An Extensive Survey of Tyrosine Phosphorylation Revealing New Sites in Human Mammary Epithelial Cells

PubMed Central

Heibeck, Tyler H.; Ding, Shi-Jian; Opresko, Lee K.; Zhao, Rui; Schepmoes, Athena A.; Yang, Feng; Tolmachev, Aleksey V.; Monroe, Matthew E.; Camp, David G.; Smith, Richard D.; Wiley, H. Steven; Qian, Wei-Jun

2010-01-01

Protein tyrosine phosphorylation represents a central regulatory mechanism in cell signaling. Here we present an extensive survey of tyrosine phosphorylation sites in a normal-derived human mammary epithelial cell line by applying anti-phosphotyrosine peptide immunoaffinity purification coupled with high sensitivity capillary liquid chromatography tandem mass spectrometry. A total of 481 tyrosine phosphorylation sites (covered by 716 unique peptides) from 285 proteins were confidently identified in HMEC following the analysis of both the basal condition and acute stimulation with epidermal growth factor (EGF). The estimated false discovery rate was 1.0% as determined by searching against a scrambled database. Comparison of these data with existing literature showed significant agreement for previously reported sites. However, we observed 281 sites that were not previously reported for HMEC cultures and 29 of which have not been reported for any human cell or tissue system. The analysis showed that the majority of highly phosphorylated proteins were relatively low-abundance. Large differences in phosphorylation stoichiometry for sites within the same protein were also observed, raising the possibility of more important functional roles for such highly phosphorylated pTyr sites. By mapping to major signaling networks, such as the EGF receptor and insulin growth factor-1 receptor signaling pathways, many known proteins involved in these pathways were revealed to be tyrosine phosphorylated, which provides interesting targets for future hypothesis-driven and targeted quantitative studies involving tyrosine phosphorylation in HMEC or other human systems. PMID:19534553

Phosphorylation of Krüppel-like factor 3 (KLF3/BKLF) and C-terminal binding protein 2 (CtBP2) by homeodomain-interacting protein kinase 2 (HIPK2) modulates KLF3 DNA binding and activity.

PubMed

Dewi, Vitri; Kwok, Alister; Lee, Stella; Lee, Ming Min; Tan, Yee Mun; Nicholas, Hannah R; Isono, Kyo-ichi; Wienert, Beeke; Mak, Ka Sin; Knights, Alexander J; Quinlan, Kate G R; Cordwell, Stuart J; Funnell, Alister P W; Pearson, Richard C M; Crossley, Merlin

2015-03-27

Krüppel-like factor 3 (KLF3/BKLF), a member of the Krüppel-like factor (KLF) family of transcription factors, is a widely expressed transcriptional repressor with diverse biological roles. Although there is considerable understanding of the molecular mechanisms that allow KLF3 to silence the activity of its target genes, less is known about the signal transduction pathways and post-translational modifications that modulate KLF3 activity in response to physiological stimuli. We observed that KLF3 is modified in a range of different tissues and found that the serine/threonine kinase homeodomain-interacting protein kinase 2 (HIPK2) can both bind and phosphorylate KLF3. Mass spectrometry identified serine 249 as the primary phosphorylation site. Mutation of this site reduces the ability of KLF3 to bind DNA and repress transcription. Furthermore, we also determined that HIPK2 can phosphorylate the KLF3 co-repressor C-terminal binding protein 2 (CtBP2) at serine 428. Finally, we found that phosphorylation of KLF3 and CtBP2 by HIPK2 strengthens the interaction between these two factors and increases transcriptional repression by KLF3. Taken together, our results indicate that HIPK2 potentiates the activity of KLF3. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

p21-Activated kinase (Pak) regulates airway smooth muscle contraction by regulating paxillin complexes that mediate actin polymerization.

PubMed

Zhang, Wenwu; Huang, Youliang; Gunst, Susan J

2016-09-01

In airway smooth muscle, tension development caused by a contractile stimulus requires phosphorylation of the 20 kDa myosin light chain (MLC), which activates crossbridge cycling and the polymerization of a pool of submembraneous actin. The p21-activated kinases (Paks) can regulate the contractility of smooth muscle and non-muscle cells, and there is evidence that this occurs through the regulation of MLC phosphorylation. We show that Pak has no effect on MLC phosphorylation during the contraction of airway smooth muscle, and that it regulates contraction by mediating actin polymerization. We find that Pak phosphorylates the adhesion junction protein, paxillin, on Ser273, which promotes the formation of a signalling complex that activates the small GTPase, cdc42, and the actin polymerization catalyst, neuronal Wiskott-Aldrich syndrome protein (N-WASP). These studies demonstrate a novel role for Pak in regulating the contractility of smooth muscle by regulating actin polymerization. The p21-activated kinases (Pak) can regulate contractility in smooth muscle and other cell and tissue types, but the mechanisms by which Paks regulate cell contractility are unclear. In airway smooth muscle, stimulus-induced contraction requires phosphorylation of the 20 kDa light chain of myosin, which activates crossbridge cycling, as well as the polymerization of a small pool of actin. The role of Pak in airway smooth muscle contraction was evaluated by inhibiting acetylcholine (ACh)-induced Pak activation through the expression of a kinase inactive mutant, Pak1 K299R, or by treating tissues with the Pak inhibitor, IPA3. Pak inhibition suppressed actin polymerization and contraction in response to ACh, but it did not affect myosin light chain phosphorylation. Pak activation induced paxillin phosphorylation on Ser273; the paxillin mutant, paxillin S273A, inhibited paxillin Ser273 phosphorylation and inhibited actin polymerization and contraction. Immunoprecipitation analysis of tissue extracts and proximity ligation assays in dissociated cells showed that Pak activation and paxillin Ser273 phosphorylation triggered the formation of an adhesion junction signalling complex with paxillin that included G-protein-coupled receptor kinase-interacting protein (GIT1) and the cdc42 guanine exchange factor, βPIX (Pak interactive exchange factor). Assembly of the Pak-GIT1-βPIX-paxillin complex was necessary for cdc42 and neuronal Wiskott-Aldrich syndrome protein (N-WASP) activation, actin polymerization and contraction in response to ACh. RhoA activation was also required for the recruitment of Pak to adhesion junctions, Pak activation, paxillin Ser273 phosphorylation and paxillin complex assembly. These studies demonstrate a novel role for Pak in the regulation of N-WASP activation, actin dynamics and cell contractility. © 2016 The Authors. The Journal of Physiology © 2016 The Physiological Society.

p21‐Activated kinase (Pak) regulates airway smooth muscle contraction by regulating paxillin complexes that mediate actin polymerization

PubMed Central

Zhang, Wenwu; Huang, Youliang

2016-01-01

Key points In airway smooth muscle, tension development caused by a contractile stimulus requires phosphorylation of the 20 kDa myosin light chain (MLC), which activates crossbridge cycling and the polymerization of a pool of submembraneous actin.The p21‐activated kinases (Paks) can regulate the contractility of smooth muscle and non‐muscle cells, and there is evidence that this occurs through the regulation of MLC phosphorylation.We show that Pak has no effect on MLC phosphorylation during the contraction of airway smooth muscle, and that it regulates contraction by mediating actin polymerization.We find that Pak phosphorylates the adhesion junction protein, paxillin, on Ser273, which promotes the formation of a signalling complex that activates the small GTPase, cdc42, and the actin polymerization catalyst, neuronal Wiskott–Aldrich syndrome protein (N‐WASP).These studies demonstrate a novel role for Pak in regulating the contractility of smooth muscle by regulating actin polymerization. Abstract The p21‐activated kinases (Pak) can regulate contractility in smooth muscle and other cell and tissue types, but the mechanisms by which Paks regulate cell contractility are unclear. In airway smooth muscle, stimulus‐induced contraction requires phosphorylation of the 20 kDa light chain of myosin, which activates crossbridge cycling, as well as the polymerization of a small pool of actin. The role of Pak in airway smooth muscle contraction was evaluated by inhibiting acetylcholine (ACh)‐induced Pak activation through the expression of a kinase inactive mutant, Pak1 K299R, or by treating tissues with the Pak inhibitor, IPA3. Pak inhibition suppressed actin polymerization and contraction in response to ACh, but it did not affect myosin light chain phosphorylation. Pak activation induced paxillin phosphorylation on Ser273; the paxillin mutant, paxillin S273A, inhibited paxillin Ser273 phosphorylation and inhibited actin polymerization and contraction. Immunoprecipitation analysis of tissue extracts and proximity ligation assays in dissociated cells showed that Pak activation and paxillin Ser273 phosphorylation triggered the formation of an adhesion junction signalling complex with paxillin that included G‐protein‐coupled receptor kinase‐interacting protein (GIT1) and the cdc42 guanine exchange factor, βPIX (Pak interactive exchange factor). Assembly of the Pak–GIT1–βPIX–paxillin complex was necessary for cdc42 and neuronal Wiskott–Aldrich syndrome protein (N‐WASP) activation, actin polymerization and contraction in response to ACh. RhoA activation was also required for the recruitment of Pak to adhesion junctions, Pak activation, paxillin Ser273 phosphorylation and paxillin complex assembly. These studies demonstrate a novel role for Pak in the regulation of N‐WASP activation, actin dynamics and cell contractility. PMID:27038336

Lentiviral infection of proliferating brain macrophages in HIV and simian immunodeficiency virus encephalitis despite sterile alpha motif and histidine-aspartate domain-containing protein 1 expression

PubMed Central

Lindgren, Allison A.; Filipowicz, Adam R.; Hattler, Julian B.; Kim, Soon Ok; Chung, Hye Kyung; Kuroda, Marcelo J.; Johnson, Edward M.; Kim, Woong-Ki

2018-01-01

Objective: HIV-1 infection of the brain and related cognitive impairment remain prevalent in HIV-1-infected individuals despite combination antiretroviral therapy. Sterile alpha motif and histidine-aspartate domain-containing protein 1 (SAMHD1) is a newly identified host restriction factor that blocks the replication of HIV-1 and other retroviruses in myeloid cells. Cell cycle-regulated phosphorylation at residue Thr592 and viral protein X (Vpx)-mediated degradation of SAMHD1 have been shown to bypass SAMHD1 restriction in vitro. Herein, we investigated expression and phosphorylation of SAMHD1 in vivo in relation to macrophage infection and proliferation during the neuropathogenesis of HIV-1 and simian immunodeficiency virus (SIV) encephalitis. Methods: Using brain and other tissues from uninfected and SIV-infected macaques with or without encephalitis, we performed immunohistochemistry, multilabel fluorescence microscopy and western blot to examine the expression, localization and phosphorylation of SAMHD1. Results: The number of SAMHD1+ nuclei increased in encephalitic brains despite the presence of Vpx. Many of these cells were perivascular macrophages, although subsets of SAMHD1+ microglia and endothelial cells were also observed. The SAMHD1+ macrophages were shown to be both infected and proliferating. Moreover, the presence of cycling SAMHD1+ brain macrophages was confirmed in the tissue of HIV-1-infected patients with encephalitis. Finally, western blot analysis of brain-protein extracts from SIV-infected macaques showed that SAMHD1 protein exists in the brain mainly as an inactive Thr592-phosphorylated form. Conclusion: The ability of SAMHD1 to act as a restriction factor for SIV/HIV in the brain is likely bypassed in proliferating brain macrophages through the phosphorylation-mediated inactivation, not Vpx-mediated degradation of SAMHD1. PMID:29698322

Increased Eps15 homology domain 1 and RAB11FIP3 expression regulate breast cancer progression via promoting epithelial growth factor receptor recycling.

PubMed

Tong, Dandan; Liang, Ya-Nan; Stepanova, A A; Liu, Yu; Li, Xiaobo; Wang, Letian; Zhang, Fengmin; Vasilyeva, N V

2017-02-01

Recent research indicates that the C-terminal Eps15 homology domain 1 is associated with epithelial growth factor receptor-mediated endocytosis recycling in non-small-cell lung cancer. The aim of this study was to determine the clinical significance of Eps15 homology domain 1 gene expression in relation to phosphorylation of epithelial growth factor receptor expression in patients with breast cancer. Primary breast cancer samples from 306 patients were analyzed for Eps15 homology domain 1, RAB11FIP3, and phosphorylation of epithelial growth factor receptor expression via immunohistochemistry. The clinical significance was assessed via a multivariate Cox regression analysis, Kaplan-Meier curves, and the log-rank test. Eps15 homology domain 1 and phosphorylation of epithelial growth factor receptor were upregulated in 60.46% (185/306) and 53.92% (165/306) of tumor tissues, respectively, as assessed by immunohistochemistry. The statistical correlation analysis indicated that Eps15 homology domain 1 overexpression was positively correlated with the increases in phosphorylation of epithelial growth factor receptor ( r = 0.242, p < 0.001) and RAB11FIP3 ( r = 0.165, p = 0.005) expression. The multivariate Cox proportional hazard model analysis demonstrated that the expression of Eps15 homology domain 1 alone is a significant prognostic marker of breast cancer for the overall survival in the total, chemotherapy, and human epidermal growth factor receptor 2 (-) groups. However, the use of combined expression of Eps15 homology domain 1 and phosphorylation of epithelial growth factor receptor markers is more effective for the disease-free survival in the overall population, chemotherapy, and human epidermal growth factor receptor 2 (-) groups. Moreover, the combined markers are also significant prognostic markers of breast cancer in the human epidermal growth factor receptor 2 (+), estrogen receptor (+), and estrogen receptor (-) groups. Eps15 homology domain 1 has a tumor suppressor function, and the combined marker of Eps15 homology domain 1/phosphorylation of epithelial growth factor receptor expression was identified as a better prognostic marker in breast cancer diagnosis. Furthermore, RAB11FIP3 combines with Eps15 homology domain 1 to promote the endocytosis recycling of phosphorylation of epithelial growth factor receptor.

Opposite Effects of Dihydrosphingosine 1-Phosphate and Sphingosine 1-Phosphate on Transforming Growth Factor-β/Smad Signaling Are Mediated through the PTEN/PPM1A-dependent Pathway*S⃞

PubMed Central

Bu, Shizhong; Kapanadze, Bagrat; Hsu, Tien; Trojanowska, Maria

2008-01-01

Transforming growth factor-β (TGF-β) is an important regulator of physiological connective tissue biosynthesis and plays a central role in pathological tissue fibrosis. Previous studies have established that a biologically active lipid mediator, sphingosine 1-phosphate (S1P), mimics some of the profibrotic functions of TGF-β through cross-activation of Smad signaling. Here we report that another product of sphingosine kinase, dihydrosphingosine 1-phosphate (dhS1P), has an opposite role in the regulation of TGF-β signaling. In contrast to S1P, dhS1P inhibits TGF-β-induced Smad2/3 phosphorylation and up-regulation of collagen synthesis. The effects of dhS1P require a lipid phosphatase, PTEN, a key modulator of cell growth and survival. dhS1P stimulates phosphorylation of the C-terminal domain of PTEN and its subsequent translocation into the nucleus. We demonstrate a novel function of nuclear PTEN as a co-factor of the Smad2/3 phosphatase, PPM1A. Complex formation of PTEN with PPM1A does not require the lipid phosphatase activity but depends on phosphorylation of the serine/threonine residues located in the C-terminal domain of PTEN. Upon complex formation with PTEN, PPM1A is protected from degradation induced by the TGF-β signaling. Consequently, overexpression of PTEN abrogates TGF-β-induced Smad2/3 phosphorylation. This study establishes a novel role for nuclear PTEN in the stabilization of PPM1A. PTEN-mediated cross-talk between the sphingolipid and TGF-β signaling pathways may play an important role in physiological and pathological TGF-β signaling. PMID:18482992

Opposite effects of dihydrosphingosine 1-phosphate and sphingosine 1-phosphate on transforming growth factor-beta/Smad signaling are mediated through the PTEN/PPM1A-dependent pathway.

PubMed

Bu, Shizhong; Kapanadze, Bagrat; Hsu, Tien; Trojanowska, Maria

2008-07-11

Transforming growth factor-beta (TGF-beta) is an important regulator of physiological connective tissue biosynthesis and plays a central role in pathological tissue fibrosis. Previous studies have established that a biologically active lipid mediator, sphingosine 1-phosphate (S1P), mimics some of the profibrotic functions of TGF-beta through cross-activation of Smad signaling. Here we report that another product of sphingosine kinase, dihydrosphingosine 1-phosphate (dhS1P), has an opposite role in the regulation of TGF-beta signaling. In contrast to S1P, dhS1P inhibits TGF-beta-induced Smad2/3 phosphorylation and up-regulation of collagen synthesis. The effects of dhS1P require a lipid phosphatase, PTEN, a key modulator of cell growth and survival. dhS1P stimulates phosphorylation of the C-terminal domain of PTEN and its subsequent translocation into the nucleus. We demonstrate a novel function of nuclear PTEN as a co-factor of the Smad2/3 phosphatase, PPM1A. Complex formation of PTEN with PPM1A does not require the lipid phosphatase activity but depends on phosphorylation of the serine/threonine residues located in the C-terminal domain of PTEN. Upon complex formation with PTEN, PPM1A is protected from degradation induced by the TGF-beta signaling. Consequently, overexpression of PTEN abrogates TGF-beta-induced Smad2/3 phosphorylation. This study establishes a novel role for nuclear PTEN in the stabilization of PPM1A. PTEN-mediated cross-talk between the sphingolipid and TGF-beta signaling pathways may play an important role in physiological and pathological TGF-beta signaling.

Decoding the phosphorylation code in Hedgehog signal transduction

PubMed Central

Chen, Yongbin; Jiang, Jin

2013-01-01

Hedgehog (Hh) signaling plays pivotal roles in embryonic development and adult tissue homeostasis, and its deregulation leads to numerous human disorders including cancer. Binding of Hh to Patched (Ptc), a twelve-transmembrane protein, alleviates its inhibition of Smoothened (Smo), a seven-transmembrane protein related to G-protein-coupled receptors (GPCRs), leading to Smo phosphorylation and activation. Smo acts through intracellular signaling complexes to convert the latent transcription factor Cubitus interruptus (Ci)/Gli from a truncated repressor to a full-length activator, leading to derepression/activation of Hh target genes. Increasing evidence suggests that phosphorylation participates in almost every step in the signal relay from Smo to Ci/Gli, and that differential phosphorylation of several key pathway components may be crucial for translating the Hh morphogen gradient into graded pathway activities. In this review, we focus on the multifaceted roles that phosphorylation plays in Hh signal transduction, and discuss the conservation and difference between Drosophila and mammalian Hh signaling mechanisms. PMID:23337587

Distinct Akt phosphorylation states are required for insulin regulated Glut4 and Glut1-mediated glucose uptake.

PubMed

Beg, Muheeb; Abdullah, Nazish; Thowfeik, Fathima Shazna; Altorki, Nasser K; McGraw, Timothy E

2017-06-07

Insulin, downstream of Akt activation, promotes glucose uptake into fat and muscle cells to lower postprandial blood glucose, an enforced change in cellular metabolism to maintain glucose homeostasis. This effect is mediated by the Glut4 glucose transporter. Growth factors also enhance glucose uptake to fuel an anabolic metabolism required for tissue growth and repair. This activity is predominantly mediated by the Glut1. Akt is activated by phosphorylation of its kinase and hydrophobic motif (HM) domains. We show that insulin-stimulated Glut4-mediated glucose uptake requires PDPK1 phosphorylation of the kinase domain but not mTORC2 phosphorylation of the HM domain. Nonetheless, an intact HM domain is required for Glut4-mediated glucose uptake. Whereas, Glut1-mediated glucose uptake also requires mTORC2 phosphorylation of the HM domain, demonstrating both phosphorylation-dependent and independent roles of the HM domain in regulating glucose uptake. Thus, mTORC2 links Akt to the distinct physiologic programs related to Glut4 and Glut1-mediated glucose uptake.

Non-muscle (NM) myosin heavy chain phosphorylation regulates the formation of NM myosin filaments, adhesome assembly and smooth muscle contraction.

PubMed

Zhang, Wenwu; Gunst, Susan J

2017-07-01

Non-muscle (NM) and smooth muscle (SM) myosin II are both expressed in smooth muscle tissues, however the role of NM myosin in SM contraction is unknown. Contractile stimulation of tracheal smooth muscle tissues stimulates phosphorylation of the NM myosin heavy chain on Ser1943 and causes NM myosin filament assembly at the SM cell cortex. Expression of a non-phosphorylatable NM myosin mutant, NM myosin S1943A, in SM tissues inhibits ACh-induced NM myosin filament assembly and SM contraction, and also inhibits the assembly of membrane adhesome complexes during contractile stimulation. NM myosin regulatory light chain (RLC) phosphorylation but not SM myosin RLC phosphorylation is regulated by RhoA GTPase during ACh stimulation, and NM RLC phosphorylation is required for NM myosin filament assembly and SM contraction. NM myosin II plays a critical role in airway SM contraction that is independent and distinct from the function of SM myosin. The molecular function of non-muscle (NM) isoforms of myosin II in smooth muscle (SM) tissues and their possible role in contraction are largely unknown. We evaluated the function of NM myosin during contractile stimulation of canine tracheal SM tissues. Stimulation with ACh caused NM myosin filament assembly, as assessed by a Triton solubility assay and a proximity ligation assay aiming to measure interactions between NM myosin monomers. ACh stimulated the phosphorylation of NM myosin heavy chain on Ser1943 in tracheal SM tissues, which can regulate NM myosin IIA filament assembly in vitro. Expression of the non-phosphorylatable mutant NM myosin S1943A in SM tissues inhibited ACh-induced endogenous NM myosin Ser1943 phosphorylation, NM myosin filament formation, the assembly of membrane adhesome complexes and tension development. The NM myosin cross-bridge cycling inhibitor blebbistatin suppressed adhesome complex assembly and SM contraction without inhibiting NM myosin Ser1943 phosphorylation or NM myosin filament assembly. RhoA inactivation selectively inhibited phosphorylation of the NM myosin regulatory light chain (RLC), NM myosin filament assembly and contraction, although it did not inhibit SM RLC phosphorylation. We conclude that the assembly and activation of NM myosin II is regulated during contractile stimulation of airway SM tissues by RhoA-mediated NM myosin RLC phosphorylation and by NM myosin heavy chain Ser1943 phosphorylation. NM myosin II actomyosin cross-bridge cycling regulates the assembly of membrane adhesome complexes that mediate the cytoskeletal processes required for tension generation. NM myosin II plays a critical role in airway SM contraction that is independent and distinct from the function of SM myosin. © 2017 The Authors. The Journal of Physiology © 2017 The Physiological Society.

Germline Ablation of VGF Increases Lipolysis in White Adipose Tissue

PubMed Central

Fargali, Samira; Scherer, Thomas; Shin, Andrew C.; Sadahiro, Masato; Buettner, Christoph; Salton, Stephen R.

2012-01-01

Targeted deletion of VGF, a neuronal and endocrine secreted protein and neuropeptide precursor, produces a lean, hypermetabolic mouse that is resistant to diet-, lesion-, and genetically-induced obesity and diabetes. We hypothesized that increased sympathetic nervous system activity in Vgf−/Vgf− knockout mice is responsible for increased energy expenditure and decreased fat storage, and that increased beta-adrenergic receptor stimulation induces lipolysis in white adipose tissue (WAT) of Vgf−/Vgf− mice. We found that fat mass was markedly reduced in Vgf−/Vgf− mice. Within knockout WAT, phosphorylation of protein kinase A (PKA) substrate increased in males and females, phosphorylation of hormone sensitive lipase (HSL) (Ser563) increased in females, and levels of adipose triglyceride lipase (ATGL), comparative gene identification-58 (CGI-58), and phospho-perilipin, were higher in male Vgf−/Vgf− WAT compared to wild type, consistent with increased lipolysis. The phosphorylation of AMP-activated protein kinase (AMPK) (Thr172) and levels of the AMPK kinase, transforming growth factor β-activated kinase 1 (TAK-1), were decreased. This was associated with a decrease in HSL Ser565 phosphorylation, the site phosphorylated by AMPK, in both male and female Vgf−/Vgf− WAT. No significant differences in phosphorylation of cAMP response element binding protein (CREB) or the p42/44 mitogen-activated protein kinase (MAPK) were noted. Despite this evidence supporting increased cAMP signaling and lipolysis, lipogenesis as assessed by fatty acid synthase (FAS) protein expression and phosphorylated acetyl-CoA carboxylase (pACC) was not decreased. Our data suggest that the VGF precursor or selected VGF-derived peptides dampen sympathetic outflow pathway activity to WAT to regulate fat storage and lipolysis. PMID:22942234

[Expressions of the key proteins of the protein kinase B/mammalian target of rapamycin signaling pathway in skin tissue and wound tissue of diabetic rats].

PubMed

Huang, H; Qiu, W; Zhu, M; Zhang, Y; Cui, W H; Xing, W; Li, X Y; An, T C; Chen, M J; Guo, W; Xu, X

2016-10-20

Objective: To explore the changes in the expressions of key proteins of the protein kinase B/mammalian target of rapamycin (Akt/mTOR) signaling pathway in skin tissue and wound tissue of diabetic rats, and to elucidate the associated mechanisms. Methods: Seventy-eight SD rats aged from 7 to 8 weeks were divided into diabetes group and non-diabetes group according to the random number table, with 39 rats in each group. Rats in diabetes group were intraperitoneally injected with 20 mg/mL streptozotocin fluid in the dose of 65 mg/kg (dissolved in citrate buffer solution) for once to establish the model of diabetes mellitus. Rats in non-diabetes group were injected with the equivalent volume of citrate buffer solution in the same way. Three rats of each group were respectively selected in each week from post injection week (PIW) 1 to 8 for collection of full-thickness skin samples on the back with area approximately of 1.0 cm×1.0 cm to determine epidermal thickness with HE staining. Fifteen rats of each group were inflicted with full-thickness skin defect by resection of skin as above in PIW 1. Three rats of each group were respectively sacrificed immediately after injury and on post injury day (PID) 1, 3, 5 and 7. One piece of skin tissue around the wound edge in each rat was cut off immediately after injury, and wound tissue in each rat was cut off from PID 1 to 7. One part of the tissue was used for determination of protein expression levels of Akt, phosphorylated Akt, mTOR, and phosphorylated mTOR in skin tissue and wound tissue with Western blotting. Surplus tissue was used for observation of expressions of phosphorylated Akt and vimentin in skin tissue and wound tissue with immunofluorescent staining. Data were processed with analysis of variance of factorial design and multiple t test. Results: (1) The epidermal thicknesses in rats between the two groups were similar in PIW 1 and 2 (with t values respectively 0.25 and 1.33, P values above 0.05). From PIW 3 on, the epidermal thicknesses were significantly thinned in rats of diabetes group as compared with those of non-diabetes group (with t values from 4.44 to 9.71, P <0.05 or P <0.01). (2) Compared with those in skin tissue immediately after injury, the protein expression levels of Akt, phosphorylated Akt, mTOR, and phosphorylated mTOR in wound tissue of rats in non-diabetes group were increased remarkably from PID 1 to 7 (except for mTOR on PID 3, with t values from 3.75 to 21.44, P <0.05 or P <0.01). Compared with those in skin tissue immediately after injury, the protein expression levels of Akt and mTOR in wound tissue of rats in diabetes group were not significantly changed from PID 1 to 7 (except for mTOR on PID 1, with t values from 0.03 to 2.32, P values above 0.05), but the protein expression levels of phosphorylated Akt and phosphorylated mTOR in wound tissue were increased remarkably from PID 1 to 7 (except for phosphorylated Akt on PID 1, with t values from 3.79 to 8.11, P <0.05 or P <0.01). The protein expression levels of Akt in skin tissue of rats between the two groups were similar immediately after injury ( t =0.66, P >0.05). However, the protein expression level of phosphorylated Akt in skin tissue of rats in diabetes group immediately after injury (0.310±0.035) was significantly decreased as compared with that in non-diabetes group (0.790±0.032, t =6.20, P < 0.05). Compared with those in non-diabetes group, the protein expression levels of mTOR and phosphorylated mTOR in skin tissue of rats in diabetes group immediately after injury and the protein expression levels of Akt, phosphorylated Akt, mTOR, and phosphorylated mTOR in wound tissue from PID 1 to 7 were all significantly decreased (with t values from 3.52 to 13.44, P <0.05 or P <0.01). (3) Compared with those in skin tissue immediately after injury, the expressions of phosphorylated Akt and vimentin in wound tissue of rats in the two groups from PID 1 to 7 presented a gradually increased tendency, however, the expressions of these indexes in skin tissue and wound tissue of rats in diabetes group were significantly weaker than those in non-diabetes group. Conclusions: Trauma can stimulate activation of Akt/mTOR signaling pathway, and upregulate the expression of key proteins. The attenuation of this signaling pathway in skin tissue and wound tissue of diabetes mellitus may be the key mechanism for causing impaired healing of wound.

Recent findings and technological advances in phosphoproteomics for cells and tissues.

PubMed

von Stechow, Louise; Francavilla, Chiara; Olsen, Jesper V

2015-01-01

Site-specific phosphorylation is a fast and reversible covalent post-translational modification that is tightly regulated in cells. The cellular machinery of enzymes that write, erase and read these modifications (kinases, phosphatases and phospho-binding proteins) is frequently deregulated in different diseases, including cancer. Large-scale studies of phosphoproteins - termed phosphoproteomics - strongly rely on the use of high-performance mass spectrometric instrumentation. This powerful technology has been applied to study a great number of phosphorylation-based phenotypes. Nevertheless, many technical and biological challenges have to be overcome to identify biologically relevant phosphorylation sites in cells and tissues. This review describes different technological strategies to identify and quantify phosphorylation sites with high accuracy, without significant loss of analysis speed and reproducibility in tissues and cells. Moreover, computational tools for analysis, integration and biological interpretation of phosphorylation events are discussed.

Eukaryotic elongation factor 2 is a prognostic marker and its kinase a potential therapeutic target in HCC

PubMed Central

Pott, Leona L; Hagemann, Sascha; Reis, Henning; Lorenz, Kristina; Bracht, Thilo; Herold, Thomas; Skryabin, Boris V; Megger, Dominik A; Kälsch, Julia; Weber, Frank; Sitek, Barbara; Baba, Hideo A

2017-01-01

Hepatocellular carcinoma is a cancer with increasing incidence and largely refractory to current anticancer drugs. Since Sorafenib, a multikinase inhibitor has shown modest efficacy in advanced hepatocellular carcinoma additional treatments are highly needed. Protein phosphorylation via kinases is an important post-translational modification to regulate cell homeostasis including proliferation and apoptosis. Therefore kinases are valuable targets in cancer therapy. To this end we performed 2D differential gel electrophoresis and mass spectrometry analysis of phosphoprotein-enriched lysates of tumor and corresponding non-tumorous liver samples to detect differentially abundant phosphoproteins to screen for novel kinases as potential drug targets. We identified 34 differentially abundant proteins in phosphoprotein enriched lysates. Expression and distribution of the candidate protein eEF2 and its phosphorylated isoform was validated immunohistochemically on 78 hepatocellular carcinoma and non-tumorous tissue samples. Validation showed that total eEF2 and phosphorylated eEF2 at threonine 56 are prognostic markers for overall survival of HCC-patients. The activity of the regulating eEF2 kinase, compared between tumor and non-tumorous tissue lysates by in vitro kinase assays, is more than four times higher in tumor tissues. Functional analyzes regarding eEF2 kinase were performed in JHH5 cells with CRISPR/Cas9 mediated eEF2 kinase knock out. Proliferation and growth is decreased in eEF2 kinase knock out cells. Conclusion eEF2 and phosphorylated eEF2 are prognostic markers for survival of hepatocellular carcinoma patients and the regulating eEF2 kinase is a potential drug target for tumor therapy. PMID:28060762

TGF-β mediates early angiogenesis and latent fibrosis in an Emilin1-deficient mouse model of aortic valve disease

PubMed Central

Munjal, Charu; Opoka, Amy M.; Osinska, Hanna; James, Jeanne F.; Bressan, Giorgio M.; Hinton, Robert B.

2014-01-01

Aortic valve disease (AVD) is characterized by elastic fiber fragmentation (EFF), fibrosis and aberrant angiogenesis. Emilin1 is an elastin-binding glycoprotein that regulates elastogenesis and inhibits TGF-β signaling, but the role of Emilin1 in valve tissue is unknown. We tested the hypothesis that Emilin1 deficiency results in AVD, mediated by non-canonical (MAPK/phosphorylated Erk1 and Erk2) TGF-β dysregulation. Using histology, immunohistochemistry, electron microscopy, quantitative gene expression analysis, immunoblotting and echocardiography, we examined the effects of Emilin1 deficiency (Emilin1−/−) in mouse aortic valve tissue. Emilin1 deficiency results in early postnatal cell-matrix defects in aortic valve tissue, including EFF, that progress to latent AVD and premature death. The Emilin1−/− aortic valve displays early aberrant provisional angiogenesis and late neovascularization. In addition, Emilin1−/− aortic valves are characterized by early valve interstitial cell activation and proliferation and late myofibroblast-like cell activation and fibrosis. Interestingly, canonical TGF-β signaling (phosphorylated Smad2 and Smad3) is upregulated constitutively from birth to senescence, whereas non-canonical TGF-β signaling (phosphorylated Erk1 and Erk2) progressively increases over time. Emilin1 deficiency recapitulates human fibrotic AVD, and advanced disease is mediated by non-canonical (MAPK/phosphorylated Erk1 and Erk2) TGF-β activation. The early manifestation of EFF and aberrant angiogenesis suggests that these processes are crucial intermediate factors involved in disease progression and therefore might provide new therapeutic targets for human AVD. PMID:25056700

Eukaryotic elongation factor 2 is a prognostic marker and its kinase a potential therapeutic target in HCC.

PubMed

Pott, Leona L; Hagemann, Sascha; Reis, Henning; Lorenz, Kristina; Bracht, Thilo; Herold, Thomas; Skryabin, Boris V; Megger, Dominik A; Kälsch, Julia; Weber, Frank; Sitek, Barbara; Baba, Hideo A

2017-02-14

Hepatocellular carcinoma is a cancer with increasing incidence and largely refractory to current anticancer drugs. Since Sorafenib, a multikinase inhibitor has shown modest efficacy in advanced hepatocellular carcinoma additional treatments are highly needed. Protein phosphorylation via kinases is an important post-translational modification to regulate cell homeostasis including proliferation and apoptosis. Therefore kinases are valuable targets in cancer therapy. To this end we performed 2D differential gel electrophoresis and mass spectrometry analysis of phosphoprotein-enriched lysates of tumor and corresponding non-tumorous liver samples to detect differentially abundant phosphoproteins to screen for novel kinases as potential drug targets. We identified 34 differentially abundant proteins in phosphoprotein enriched lysates. Expression and distribution of the candidate protein eEF2 and its phosphorylated isoform was validated immunohistochemically on 78 hepatocellular carcinoma and non-tumorous tissue samples. Validation showed that total eEF2 and phosphorylated eEF2 at threonine 56 are prognostic markers for overall survival of HCC-patients. The activity of the regulating eEF2 kinase, compared between tumor and non-tumorous tissue lysates by in vitro kinase assays, is more than four times higher in tumor tissues. Functional analyzes regarding eEF2 kinase were performed in JHH5 cells with CRISPR/Cas9 mediated eEF2 kinase knock out. Proliferation and growth is decreased in eEF2 kinase knock out cells. eEF2 and phosphorylated eEF2 are prognostic markers for survival of hepatocellular carcinoma patients and the regulating eEF2 kinase is a potential drug target for tumor therapy.

The nuclear-factor kappaB pathway is activated in pterygium.

PubMed

Siak, Jay Jyh Kuen; Ng, See Liang; Seet, Li-Fong; Beuerman, Roger W; Tong, Louis

2011-01-05

Pterygium is a prevalent ocular surface disease with unknown pathogenesis. The authors investigated the role of nuclear factor kappa B (NF-κB) transcription factors in pterygium. Surgically excised primary pterygia were studied compared with uninvolved conjunctiva tissues. NF-κB activation was evaluated using Western blot analysis, ELISA, and DNA-binding assays. Primary pterygium fibroblasts were treated with TNF-α (20 ng/mL), and NF-κB activation was evaluated using immunocytochemistry, Western blot analysis, phospho-IκBα ELISA, and DNA-binding assays. TNF-α stimulation of NF-κB target genes RelB, NFKB2, RANTES, MCP-1, ENA-78, MMP-1, MMP-2, and MMP-3 in pterygium fibroblasts was compared with that in primary tenon fibroblasts by real-time PCR. Phosphorylation of IκBα (Ser32) was increased in pterygia tissues compared with uninvolved conjunctiva tissues, as determined by Western blot analysis and ELISA. IκBα expression was decreased, whereas nuclear RelA and p50 DNA-binding capacities were increased. Within 30 minutes of treatment with TNF-α, pterygium fibroblasts showed increased IκBα phosphorylation and nuclear translocation of RelA and p50. Treatment with TNF-α beyond 12 hours resulted in increased nuclear expression of RelB, p100, and p52. Furthermore, the upregulation of RANTES, MCP-1, ENA-78, MMP-1, MMP-2, and MMP-3 expression was more pronounced in TNF-α-treated pterygium fibroblasts than in tenon fibroblasts. The NF-κB pathway is shown for the first time to be activated in pterygia tissues compared with normal conjunctiva tissues. Stimulation by the inflammatory cytokine TNF-α can activate both canonical and noncanonical NF-κB pathways in pterygium fibroblasts with concomitant upregulation of NF-κB target genes.

Insight into mechanism of oxidative DNA damage in angiomyolipomas from TSC patients

PubMed Central

Habib, Samy L

2009-01-01

Background The tuberous sclerosis complex (TSC) is caused by defects in one of two tumor suppressor genes, TSC-1 or TSC-2. TSC-2 gene encodes tuberin, a protein involved in the pathogenesis of kidney tumors, both angiomyolipomas and renal cell carcinomas. Loss of heterozygosity at the 8-oxoG-DNA glycosylase (OGG1) allele is found in human kidney clear cell carcinoma identifying loss of OGG1 function as a possible contributor to tumorigenesis in the kidney. Tuberin regulates OGG1 through the transcription factor NF-YA in cultured cells. The purpose of this study is to determine the effect of tuberin-deficiency on OGG1 protein and mRNA levels as well as on 8-oxodG levels in kidney tumors from patients with TSC. In addition we evaluated the phophorylation level of downstream targets of mTOR, phospho-S70K, in kidney tumor tissue from TSC patients. Results Kidney angiomyolipoma tissue from TSC patients expresses significant levels of phopho-tuberin and low levels of tuberin compared to control kidney tissue. The increase in tuberin phosphorylation and the decrease tuberin expression are associated with decrease in OGG1 protein and mRNA levels in tumor samples compared to normal kidney samples. The decrease OGG1 expression is also associated with significant decrease in the transcription factor, NF-YA, expression in tumor samples compared to normal tissues. In addition, the levels of 8-oxodG are 4-fold higher in tumors compared to control samples. The significant increase of phospho-tuberin expression is associated with increase phosphorylation of S6K in tumor samples compared to controls. Cyclin D1 expression is also 3-fold higher in increase in the tumor tissues compared to normal kidney tissues. Conclusion These data indicate that tuberin deficiency in angiomyolipoma enhances mTOR activation by phosphorylation of S6K and downregulation of protein and mRNA expression of OGG1 resulted in accumulation of oxidized DNA in patients with TSC. These data suggest that tuberin and OGG1 are important proteins in the pathogenesis of angiomyolipoma in TSC patients. PMID:19265534

One-Step Preservation of Phosphoproteins and Tissue Morphology at Room Temperature for Diagnostic and Research Specimens

PubMed Central

Mueller, Claudius; Edmiston, Kirsten H.; Carpenter, Calvin; Gaffney, Eoin; Ryan, Ciara; Ward, Ronan; White, Susan; Memeo, Lorenzo; Colarossi, Cristina; Petricoin, Emanuel F.; Liotta, Lance A.; Espina, Virginia

2011-01-01

Background There is an urgent need to measure phosphorylated cell signaling proteins in cancer tissue for the individualization of molecular targeted kinase inhibitor therapy. However, phosphoproteins fluctuate rapidly following tissue procurement. Snap-freezing preserves phosphoproteins, but is unavailable in most clinics and compromises diagnostic morphology. Formalin fixation preserves tissue histomorphology, but penetrates tissue slowly, and is unsuitable for stabilizing phosphoproteins. We originated and evaluated a novel one-step biomarker and histology preservative (BHP) chemistry that stabilizes signaling protein phosphorylation and retains formalin-like tissue histomorphology with equivalent immunohistochemistry in a single paraffin block. Results Total protein yield extracted from BHP-fixed, routine paraffin-embedded mouse liver was 100% compared to snap-frozen tissue. The abundance of 14 phosphorylated proteins was found to be stable over extended fixation times in BHP fixed paraffin embedded human colon mucosa. Compared to matched snap-frozen tissue, 8 phosphoproteins were equally preserved in mouse liver, while AMPKβ1 Ser108 was slightly elevated after BHP fixation. More than 25 tissues from mouse, cat and human specimens were evaluated for preservation of histomorphology. Selected tissues were evaluated in a multi-site, independent pathology review. Tissue fixed with BHP showed equivalent preservation of cytoplasmic and membrane cytomorphology, with significantly better nuclear chromatin preservation by BHP compared to formalin. Immunohistochemical staining of 13 non-phosphorylated proteins, including estrogen receptor alpha, progesterone receptor, Ki-67 and Her2, was equal to or stronger in BHP compared to formalin. BHP demonstrated significantly improved immunohistochemical detection of phosphorylated proteins ERK Thr202/Tyr204, GSK3-α/β Ser21/Ser9, p38-MAPK Thr180/Tyr182, eIF4G Ser1108 and Acetyl-CoA Carboxylase Ser79. Conclusion In a single paraffin block BHP preserved the phosphorylation state of several signaling proteins at a level comparable to snap-freezing, while maintaining the full diagnostic immunohistochemical and histomorphologic detail of formalin fixation. This new tissue fixative has the potential to greatly facilitate personalized medicine, biobanking, and phospho-proteomic research. PMID:21858221

PI3K/Akt is involved in brown adipogenesis mediated by growth differentiation factor-5 in association with activation of the Smad pathway

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hinoi, Eiichi; Iezaki, Takashi; Fujita, Hiroyuki

2014-07-18

Highlights: • Akt is preferentially phosphorylated in BAT and sWAT of aP2-GDF5 mice. • PI3K/Akt signaling is involved in GDF5-induced brown adipogenesis. • PI3K/Akt signaling regulates GDF5-induced Smad5 phosphorylation. - Abstract: We have previously demonstrated promotion by growth differentiation factor-5 (GDF5) of brown adipogenesis for systemic energy expenditure through a mechanism relevant to activating the bone morphological protein (BMP) receptor/mothers against decapentaplegic homolog (Smad)/peroxisome proliferator-activated receptor gamma co-activator 1α (PGC-1α) pathway. Here, we show the involvement of the phosphatidylinositol 3-kinase (PI3K)/Akt pathway in brown adipogenesis mediated by GDF5. Overexpression of GDF5 in cells expressing adipocyte protein-2 markedly accelerated the phosphorylationmore » of Smad1/5/8 and Akt in white and brown adipose tissues. In brown adipose tissue from heterozygous GDF5{sup Rgsc451} mutant mice expressing a dominant-negative (DN) GDF5 under obesogenic conditions, the basal phosphorylation of Smad1/5/8 and Akt was significantly attenuated. Exposure to GDF5 not only promoted the phosphorylation of both Smad1/5/8 and Akt in cultured brown pre-adipocytes, but also up-regulated Pgc1a and uncoupling protein-1 expression in a manner sensitive to the PI3K/Akt inhibitor Ly294002 as well as retroviral infection with DN-Akt. GDF5 drastically promoted BMP-responsive luciferase reporter activity in a Ly294002-sensitive fashion. Both Ly294002 and DN-Akt markedly inhibited phosphorylation of Smad5 in the nuclei of brown pre-adipocytes. These results suggest that PI3K/Akt signals play a role in the GDF5-mediated brown adipogenesis through a mechanism related to activation of the Smad pathway.« less

Organic conjugated small molecule materials based optical probe for rapid, colorimetric and UV-vis spectral detection of phosphorylated protein in placental tissue

NASA Astrophysics Data System (ADS)

Wang, Yanfang; Yang, Na; Liu, Yi

2018-04-01

A novel organic small molecule with D-Pi-A structure was prepared, which was found to be a promising colorimetric and ratiometric UV-vis spetral probe for detection of phosphorylated proteins with the help of tetravalent zirconium ion. Such optical probe based on chromophore WYF-1 shows a rapid response (within 10 s) and high selectivity and sensitivity for phosphorylated proteins, giving distinct colorimetric and ratiometric UV-vis changes at 720 and 560 nm. The detection limit for phosphorylated proteins was estimated to be 100 nM. In addition, detection of phosphorylated proteins in placental tissue samples with this probe was successfully applied, which indicates that this probe holds great potential for phosphorylated proteins detection.

Short-Term Treatment with Bisphenol-A Leads to Metabolic Abnormalities in Adult Male Mice

PubMed Central

Batista, Thiago M.; Alonso-Magdalena, Paloma; Vieira, Elaine; Amaral, Maria Esmeria C.; Cederroth, Christopher R.; Nef, Serge; Quesada, Ivan; Carneiro, Everardo M.; Nadal, Angel

2012-01-01

Bisphenol-A (BPA) is one of the most widespread endocrine disrupting chemicals (EDC) used as the base compound in the manufacture of polycarbonate plastics. Although evidence points to consider exposure to BPA as a risk factor for insulin resistance, its actions on whole body metabolism and on insulin-sensitive tissues are still unclear. The aim of the present work was to study the effects of low doses of BPA in insulin-sensitive peripheral tissues and whole body metabolism in adult mice. Adult mice were treated with subcutaneous injection of 100 µg/kg BPA or vehicle for 8 days. Whole body energy homeostasis was assessed with in vivo indirect calorimetry. Insulin signaling assays were conducted by western blot analysis. Mice treated with BPA were insulin resistant and had increased glucose-stimulated insulin release. BPA-treated mice had decreased food intake, lower body temperature and locomotor activity compared to control. In skeletal muscle, insulin-stimulated tyrosine phosphorylation of the insulin receptor β subunit was impaired in BPA-treated mice. This impairment was associated with a reduced insulin-stimulated Akt phosphorylation in the Thr308 residue. Both skeletal muscle and liver displayed an upregulation of IRS-1 protein by BPA. The mitogen-activated protein kinase (MAPK) signaling pathway was also impaired in the skeletal muscle from BPA-treated mice. In the liver, BPA effects were of lesser intensity with decreased insulin-stimulated tyrosine phosphorylation of the insulin receptor β subunit. In conclusion, short-term treatment with low doses of BPA slows down whole body energy metabolism and disrupts insulin signaling in peripheral tissues. Thus, our findings support the notion that BPA can be considered a risk factor for the development of type 2 diabetes. PMID:22470480

No Effect of a Whey Growth Factor Extract during Resistance Training on Strength, Body Composition, or Hypertrophic Gene Expression in Resistance-Trained Young Men.

PubMed

Dale, Michael J; Coates, Alison M; Howe, Peter R C; Tomkinson, Grant R; Haren, Matthew T; Brown, Andrew; Caldow, Marissa; Cameron-Smith, David; Buckley, Jonathan D

2017-06-01

Growth factors can be isolated from bovine milk to form a whey growth factor extract (WGFE). This study examined whether WGFE promoted activation of the AKT/mTOR pathway enabling increased lean tissue mass and strength in resistance trained men. Forty six men with >6 months of resistance training (RT) experience performed 12 weeks of RT. Participants consumed 20 g/day of whey protein and were randomised to receive either 1.6 g WGFE/day (WGFE; n = 22) or 1.6 g cellulose/day (control, CONT; n = 24). The primary outcome was leg press one-repetition maximum (LP1-RM) which was assessed at baseline, 6 and 12 weeks. At baseline and 12 weeks body composition was assessed by dual energy x-ray absorptiometry, and muscle protein synthesis and gene expression were assessed (vastus lateralis biopsy) in a sub-sample (WGFE n = 10, CONT n = 10) pre- and 3 hr post-training. RT increased LP1-RM (+34.9%) and lean tissue mass (+2.3%; p < 0.05) with no difference between treatments (p > 0.48, treatment x time). Post-exercise P70 s6k phosphorylation increased acutely, FOXO3a phosphorylation was unaltered. There were no differences in kinase signalling or gene expression between treatments. Compared with CONT, WGFE did not result in greater increases in lean tissue mass or strength in experienced resistance trained men.

Organic conjugated small molecule materials based optical probe for rapid, colorimetric and UV-vis spectral detection of phosphorylated protein in placental tissue.

PubMed

Wang, Yanfang; Yang, Na; Liu, Yi

2018-04-05

A novel organic small molecule with D-Pi-A structure was prepared, which was found to be a promising colorimetric and ratiometric UV-vis spetral probe for detection of phosphorylated proteins with the help of tetravalent zirconium ion. Such optical probe based on chromophore WYF-1 shows a rapid response (within 10s) and high selectivity and sensitivity for phosphorylated proteins, giving distinct colorimetric and ratiometric UV-vis changes at 720 and 560nm. The detection limit for phosphorylated proteins was estimated to be 100nM. In addition, detection of phosphorylated proteins in placental tissue samples with this probe was successfully applied, which indicates that this probe holds great potential for phosphorylated proteins detection. Copyright © 2018 Elsevier B.V. All rights reserved.

Selenium Pretreatment for Mitigation of Ischemia/Reperfusion Injury in Cardiovascular Surgery: Influence on Acute Organ Damage and Inflammatory Response.

PubMed

Steinbrenner, Holger; Bilgic, Esra; Pinto, Antonio; Engels, Melanie; Wollschläger, Lena; Döhrn, Laura; Kellermann, Kristine; Boeken, Udo; Akhyari, Payam; Lichtenberg, Artur

2016-08-01

Ischemia/reperfusion injury (IRI) contributes to morbidity and mortality after cardiovascular surgery requiring cardiopulmonary bypass (CPB) and deep hypothermic circulatory arrest (DHCA). Multi-organ damage is associated with substantial decreases of blood selenium (Se) levels in patients undergoing cardiac surgery with CPB. We compared the influence of a dietary surplus of Se and pretreatment with ebselen, a mimic of the selenoenzyme glutathione peroxidase, on IRI-induced tissue damage and inflammation. Male Wistar rats were fed either a Se-adequate diet containing 0.3 ppm Se or supplemented with 1 ppm Se (as sodium selenite) for 5 weeks. Two other groups of Se-adequate rats received intraperitoneal injection of ebselen (30 mg/kg) or DMSO (solvent control) before surgery. The animals were connected to a heart-lung-machine and underwent 45 min of global ischemia during circulatory arrest at 16 °C, followed by re-warming and reperfusion. Selenite and ebselen suppressed IRI-induced leukocytosis and the increase in plasma levels of tissue damage markers (AST, ALT, LDH, troponin) during surgery but did not prevent the induction of proinflammatory cytokines (IL-6, TNF-α). Both Se compounds affected phosphorylation and expression of proteins related to stress response and inflammation: Ebselen increased phosphorylation of STAT3 transcription factor in the heart and decreased phosphorylation of ERK1/2 MAP kinases in the lungs. Selenite decreased ERK1/2 phosphorylation and HSP-70 expression in the heart. Pretreatment with selenite or ebselen protected against acute IRI-induced tissue damage during CPB and DHCA. Potential implications of their different actions with regard to molecular stress markers on the recovery after surgery represent promising targets for further investigation.

Regulation of Catalytic and Non-catalytic Functions of the Drosophila Ste20 Kinase Slik by Activation Segment Phosphorylation.

PubMed

Panneton, Vincent; Nath, Apurba; Sader, Fadi; Delaunay, Nathalie; Pelletier, Ariane; Maier, Dominic; Oh, Karen; Hipfner, David R

2015-08-21

Protein kinases carry out important functions in cells both by phosphorylating substrates and by means of regulated non-catalytic activities. Such non-catalytic functions have been ascribed to many kinases, including some members of the Ste20 family. The Drosophila Ste20 kinase Slik phosphorylates and activates Moesin in developing epithelial tissues to promote epithelial tissue integrity. It also functions non-catalytically to promote epithelial cell proliferation and tissue growth. We carried out a structure-function analysis to determine how these two distinct activities of Slik are controlled. We find that the conserved C-terminal coiled-coil domain of Slik, which is necessary and sufficient for apical localization of the kinase in epithelial cells, is not required for Moesin phosphorylation but is critical for the growth-promoting function of Slik. Slik is auto- and trans-phosphorylated in vivo. Phosphorylation of at least two of three conserved sites in the activation segment is required for both efficient catalytic activity and non-catalytic signaling. Slik function is thus dependent upon proper localization of the kinase via the C-terminal coiled-coil domain and activation via activation segment phosphorylation, which enhances both phosphorylation of substrates like Moesin and engagement of effectors of its non-catalytic growth-promoting activity. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

Enhanced mitogenesis in stromal vascular cells derived from subcutaneous adipose tissue of Wagyu compared with those of Angus cattle.

PubMed

Wei, S; Fu, X; Liang, X; Zhu, M J; Jiang, Z; Parish, S M; Dodson, M V; Zan, L; Du, M

2015-03-01

Japanese Wagyu cattle are well known for their extremely high marbling and lower subcutaneous adipose tissue compared with Angus cattle. However, mechanisms for differences in adipose deposition are unknown. The objective of this paper was to evaluate breed differences in the structure of subcutaneous adipose tissue, adipogenesis, and mitogenesis of stromal vascular (SV) cells between Wagyu and Angus cattle. Subcutaneous biopsy samples were obtained from 5 Wagyu (BW = 302 ± 9 kg) and 5 Angus (BW = 398 ± 12 kg) heifers at 12 mo of age, and samples were divided into 3 pieces for histological examination, biochemical analysis, and harvest of SV cells. Adipogenesis of SV cells was assessed by the expression of adipogenic markers and Oil Red-O staining, while mitogenesis was evaluated by an MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium dromide) test, phosphorylation of extracellular signal-regulated kinase (ERK) and protein kinase B (PKB; AKT). Based on histological analysis, Wagyu had larger adipocytes compared with Angus. At the tissue level, protein expression of peroxisome proliferator-activated receptor γ (PPARG) in Wagyu was much lower compared with that of Angus. Similarly, a lower mRNA expression of PPARG was found in Wagyu SV cells. No significant difference was observed for the zinc finger protein 423 (ZNF423) expression between Wagyu and Angus. As assessed by Oil Red-O staining, Wagyu SV cells possessed a notable trend of lower adipogenic capability. Interestingly, higher mitogenic ability was discovered in Wagyu SV cells, which was associated with an elevated phosphorylation of ERK1/2. There was no difference in AKT phosphorylation of SV cells between Wagyu and Angus. Moreover, exogenous fibroblast growth factor 2 (FGF2) enhanced mitogenesis and ERK1/2 phosphorylation of SV cells to a greater degree in Angus compared with that in Wagyu. Expression of transforming growth factor β 3 (TGFB3) and bone morphogenetic protein 2 (BMP2) in Wagyu SV cells was lower than that of Angus, providing potential clues for breed differences on proliferation of SV cells in these two cattle breeds. The results of this study suggest that subcutaneous adipose-derived SV cells of Wagyu possess a lower trend of adipogenesis but higher mitogenesis compared with those of Angus.

Long-term high-fat consumption leads to downregulation of Akt phosphorylation of eNOS at Ser1177 and upregulation of Sirtuin-1 expression in rat cavernous tissue.

PubMed

Tomada, I; Negrão, R; Almeida, H; Neves, D

2014-04-01

Long-term consumption of high-fat diets negatively interferes with metabolic status and promotes endothelial dysfunction and inflammation. In the cavernous tissue, these outcomes become conspicuous in the elderly and strongly affect penile erection, a vascular process highly dependent on local nitric oxide bioavailability. Although epidemiological data links erectile dysfunction to nutritional patterns, the underlying molecular mechanisms remain unclear. Therefore, we investigated the effects of long-term high-fat diet on endothelial nitric oxide synthase (eNOS)-Sirtuin-1 axis and Akt/eNOS phosphorylation in the cavernous tissue of Sprague-Dawley rats, and compared with energy-restricted animals. We demonstrated that high-fat diet intake led to a noteworthy decrease in eNOS phosphorylation at Ser1177 residue through the Akt pathway, which seems to be compensated by upregulation of phosphorylation at Ser615, but without an increment in nitric oxide production. These results are accompanied by an increase of systemic inflammatory markers and upregulation of the inducible NOS and of the deacetylase Sirtuin-1 in the cavernous tissue to levels apparently detrimental to cells and to metabolic homeostasis. Conversely, in long-term energy-restricted animals, the rate of phosphorylation of eNOS at Ser1177 diminished, but the activation of the enzyme increased through phosphorylation of eNOS at Ser615, resulting in an enhancement in nitric oxide bioavailability. Taken together, our results demonstrate that long-term nutritional conditions override the influence of age on the eNOS expression and activation in rat cavernous tissue.

Smooth muscle myosin light chain kinase efficiently phosphorylates serine 15 of cardiac myosin regulatory light chain

DOE Office of Scientific and Technical Information (OSTI.GOV)

Josephson, Matthew P.; Sikkink, Laura A.; Penheiter, Alan R.

2011-12-16

Highlights: Black-Right-Pointing-Pointer Cardiac myosin regulatory light chain (MYL2) is phosphorylated at S15. Black-Right-Pointing-Pointer Smooth muscle myosin light chain kinase (smMLCK) is a ubiquitous kinase. Black-Right-Pointing-Pointer It is a widely believed that MYL2 is a poor substrate for smMLCK. Black-Right-Pointing-Pointer In fact, smMLCK efficiently and rapidly phosphorylates S15 in MYL2. Black-Right-Pointing-Pointer Phosphorylation kinetics measured by novel fluorescence method without radioactivity. -- Abstract: Specific phosphorylation of the human ventricular cardiac myosin regulatory light chain (MYL2) modifies the protein at S15. This modification affects MYL2 secondary structure and modulates the Ca{sup 2+} sensitivity of contraction in cardiac tissue. Smooth muscle myosin light chainmore » kinase (smMLCK) is a ubiquitous kinase prevalent in uterus and present in other contracting tissues including cardiac muscle. The recombinant 130 kDa (short) smMLCK phosphorylated S15 in MYL2 in vitro. Specific modification of S15 was verified using the direct detection of the phospho group on S15 with mass spectrometry. SmMLCK also specifically phosphorylated myosin regulatory light chain S15 in porcine ventricular myosin and chicken gizzard smooth muscle myosin (S20 in smooth muscle) but failed to phosphorylate the myosin regulatory light chain in rabbit skeletal myosin. Phosphorylation kinetics, measured using a novel fluorescence method eliminating the use of radioactive isotopes, indicates similar Michaelis-Menten V{sub max} and K{sub M} for regulatory light chain S15 phosphorylation rates in MYL2, porcine ventricular myosin, and chicken gizzard myosin. These data demonstrate that smMLCK is a specific and efficient kinase for the in vitro phosphorylation of MYL2, cardiac, and smooth muscle myosin. Whether smMLCK plays a role in cardiac muscle regulation or response to a disease causing stimulus is unclear but it should be considered a potentially significant kinase in cardiac tissue on the basis of its specificity, kinetics, and tissue expression.« less

Interactome Mapping Guided by Tissue-Specific Phosphorylation in Age-Related Macular Degeneration

PubMed Central

Sripathi, Srinivas R.; He, Weilue; Prigge, Cameron L.; Sylvester, O’Donnell; Um, Ji-Yeon; Powell, Folami L.; Neksumi, Musa; Bernstein, Paul S.; Choo, Dong-Won; Bartoli, Manuela; Gutsaeva, Diana R.; Jahng, Wan Jin

2017-01-01

The current study aims to determine the molecular mechanisms of age-related macular degeneration (AMD) using the phosphorylation network. Specifically, we examined novel biomarkers for oxidative stress by protein interaction mapping using in vitro and in vivo models that mimic the complex and progressive characteristics of AMD. We hypothesized that the early apoptotic reactions could be initiated by protein phosphorylation in region-dependent (peripheral retina vs. macular) and tissue-dependent (retinal pigment epithelium vs. retina) manner under chronic oxidative stress. The analysis of protein interactome and oxidative biomarkers showed the presence of tissue- and region-specific post-translational mechanisms that contribute to AMD progression and suggested new therapeutic targets that include ubiquitin, erythropoietin, vitronectin, MMP2, crystalline, nitric oxide, and prohibitin. Phosphorylation of specific target proteins in RPE cells is a central regulatory mechanism as a survival tool under chronic oxidative imbalance. The current interactome map demonstrates a positive correlation between oxidative stress-mediated phosphorylation and AMD progression and provides a basis for understanding oxidative stress-induced cytoskeletal changes and the mechanism of aggregate formation induced by protein phosphorylation. This information could provide an effective therapeutic approach to treat age-related neurodegeneration. PMID:28580316

Interactome Mapping Guided by Tissue-Specific Phosphorylation in Age-Related Macular Degeneration.

PubMed

Sripathi, Srinivas R; He, Weilue; Prigge, Cameron L; Sylvester, O'Donnell; Um, Ji-Yeon; Powell, Folami L; Neksumi, Musa; Bernstein, Paul S; Choo, Dong-Won; Bartoli, Manuela; Gutsaeva, Diana R; Jahng, Wan Jin

2017-02-01

The current study aims to determine the molecular mechanisms of age-related macular degeneration (AMD) using the phosphorylation network. Specifically, we examined novel biomarkers for oxidative stress by protein interaction mapping using in vitro and in vivo models that mimic the complex and progressive characteristics of AMD. We hypothesized that the early apoptotic reactions could be initiated by protein phosphorylation in region-dependent (peripheral retina vs. macular) and tissue-dependent (retinal pigment epithelium vs. retina) manner under chronic oxidative stress. The analysis of protein interactome and oxidative biomarkers showed the presence of tissue- and region-specific post-translational mechanisms that contribute to AMD progression and suggested new therapeutic targets that include ubiquitin, erythropoietin, vitronectin, MMP2, crystalline, nitric oxide, and prohibitin. Phosphorylation of specific target proteins in RPE cells is a central regulatory mechanism as a survival tool under chronic oxidative imbalance. The current interactome map demonstrates a positive correlation between oxidative stress-mediated phosphorylation and AMD progression and provides a basis for understanding oxidative stress-induced cytoskeletal changes and the mechanism of aggregate formation induced by protein phosphorylation. This information could provide an effective therapeutic approach to treat age-related neurodegeneration.

Protein Phosphorylation Profiling Using an In Situ Proximity Ligation Assay: Phosphorylation of AURKA-Elicited EGFR-Thr654 and EGFR-Ser1046 in Lung Cancer Cells

PubMed Central

Chen, Tzu-Chi; Liu, Yu-Wen; Huang, Yei-Hsuan; Yeh, Yi-Chen; Chou, Teh-Ying; Wu, Yu-Chung; Wu, Chun-Chi; Chen, Yi-Rong; Cheng, Hui-Chuan; Lu, Pei-Jung; Lai, Jin-Mei; Huang, Chi-Ying F.

2013-01-01

The epidermal growth factor receptor (EGFR), which is up-regulated in lung cancer, involves the activation of mitogenic signals and triggers multiple signaling cascades. To dissect these EGFR cascades, we used 14 different phospho-EGFR antibodies to quantify protein phosphorylation using an in situ proximity ligation assay (in situ PLA). Phosphorylation at EGFR-Thr654 and -Ser1046 was EGF-dependent in the wild-type (WT) receptor but EGF-independent in a cell line carrying the EGFR-L858R mutation. Using a ProtoAarray™ containing ∼5000 recombinant proteins on the protein chip, we found that AURKA interacted with the EGFR-L861Q mutant. Moreover, overexpression of EGFR could form a complex with AURKA, and the inhibitors of AURKA and EGFR decreased EGFR-Thr654 and -Ser1046 phosphorylation. Immunohistochemical staining of stage I lung adenocarcinoma tissues demonstrated a positive correlation between AURKA expression and phosphorylation of EGFR at Thr654 and Ser1046 in EGFR-mutant specimens, but not in EGFR-WT specimens. The interplay between EGFR and AURKA provides an explanation for the difference in EGF dependency between EGFR-WT and EGFR-mutant cells and may provide a new therapeutic strategy for lung cancer patients carrying EGFR mutations. PMID:23520446

Phenytoin enhances the phosphorylation of epidermal growth factor receptor and fibroblast growth factor receptor in the subventricular zone and promotes the proliferation of neural precursor cells and oligodendrocyte differentiation.

PubMed

Galvez-Contreras, Alma Y; Gonzalez-Castaneda, Rocio E; Campos-Ordonez, Tania; Luquin, Sonia; Gonzalez-Perez, Oscar

2016-01-01

Phenytoin is a widely used antiepileptic drug that induces cell proliferation in several tissues, such as heart, bone, skin, oral mucosa and neural precursors. Some of these effects are mediated via fibroblast growth factor receptor (FGFR) and epidermal growth factor receptor (EGFR). These receptors are strongly expressed in the adult ventricular-subventricular zone (V-SVZ), the main neurogenic niche in the adult brain. The aim of this study was to determine the cell lineage and cell fate of V-SVZ neural progenitors expanded by phenytoin, as well as the effects of this drug on EGFR/FGFR phosphorylation. Male BALB/C mice received 10 mg/kg phenytoin by oral cannula for 30 days. We analysed the proliferation of V-SVZ neural progenitors by immunohistochemistry and western blot. Our findings indicate that phenytoin enhanced twofold the phosphorylation of EGFR and FGFR in the V-SVZ, increased the number of bromodeoxyuridine (BrdU)+/Sox2+ and BrdU+/doublecortin+ cells in the V-SVZ, and expanded the population of Olig2-expressing cells around the lateral ventricles. After phenytoin removal, a large number of BrdU+/Receptor interacting protein (RIP)+ cells were observed in the olfactory bulb. In conclusion, phenytoin enhanced the phosphorylation of FGFR and EGFR, and promoted the expression of neural precursor markers in the V-SVZ. In parallel, the number of oligodendrocytes increased significantly after phenytoin removal. © 2015 Federation of European Neuroscience Societies and John Wiley & Sons Ltd.

ATF3 activates Stat3 phosphorylation through inhibition of p53 expression in skin cancer cells.

PubMed

Hao, Zhen-Feng; Ao, Jun-Hong; Zhang, Jie; Su, You-Ming; Yang, Rong-Ya

2013-01-01

ATF3, a member of the ATF/CREB family of transcription factors, has been found to be selectively induced by calcineurin/NFAT inhibition and to enhance keratinocyte tumor formation, although the precise role of ATF3 in human skin cancer and possible mechanisms remain unknown. In this study, clinical analysis of 30 skin cancer patients and 30 normal donors revealed that ATF3 was accumulated in skin cancer tissues. Functional assays demonstrated that ATF3 significantly promoted skin cancer cell proliferation. Mechanically, ATF3 activated Stat3 phosphorylation in skin cancer cell through regulation of p53 expression. Moreover, the promotion effect of ATF3 on skin cancer cell proliferation was dependent on the p53-Stat3 signaling cascade. Together, the results indicate that ATF3 might promote skin cancer cell proliferation and enhance skin keratinocyte tumor development through inhibiting p53 expression and then activating Stat3 phosphorylation.

Sulfur mustard analog induces oxidative stress and activates signaling cascades in the skin of SKH-1 hairless mice.

PubMed

Pal, Arttatrana; Tewari-Singh, Neera; Gu, Mallikarjuna; Agarwal, Chapla; Huang, Jie; Day, Brian J; White, Carl W; Agarwal, Rajesh

2009-12-01

A monofunctional analog of the chemical warfare agent sulfur mustard (HD), 2-chloroethyl ethyl sulfide (CEES), induces tissue damage similar to HD. Herein we studied the molecular mechanisms associated with CEES-induced skin inflammation and toxicity in SKH-1 hairless mice. Topical CEES exposure caused an increase in oxidative stress as observed by enhanced 4-hydroxynonenal and 5,5-dimethyl-2-(8-octanoic acid)-1-pyrroline N-oxide protein adduct formation and an increase in protein oxidation. The CEES-induced increase in the formation of 8-oxo-2-deoxyguanosine indicated DNA oxidation. CEES exposure instigated an increase in the phosphorylation of mitogen-activated protein kinases (MAPKs; ERK1/2, JNK, and p38). After CEES exposure, a significant increase in the phosphorylation of Akt at Ser473 and Thr308 was observed as well as upregulation of its upstream effector, PDK1, in mouse skin tissue. Subsequently, CEES exposure caused activation of AP-1 family proteins and the NF-kappaB pathway, including phosphorylation and degradation of IkappaBalpha in addition to phosphorylation of the NF-kappaB essential modulator. Collectively, our results indicate that CEES induces oxidative stress and the activation of the transcription factors AP-1 and NF-kappaB via upstream signaling pathways including MAPKs and Akt in SKH-1 hairless mouse skin. These novel molecular targets could be supportive in the development of prophylactic and therapeutic interventions against HD-related skin injury.

Neurofilament protein levels: quantitative analysis in essential tremor cerebellar cortex.

PubMed

Louis, Elan D; Ma, Karen; Babij, Rachel; Cortés, Etty; Liem, Ronald K; Vonsattel, Jean-Paul G; Faust, Phyllis L

2012-06-14

Essential tremor (ET) is among the most prevalent neurological diseases. A substantial increase in the number of Purkinje cell axonal swellings (torpedoes) has been identified in ET brains. We recently demonstrated that torpedoes in ET contain an over-accumulation of disorganized neurofilament (NF) proteins. This now raises the question whether NF protein composition and/or phosphorylation state in cerebellar tissue might differ between ET cases and controls. We used a Western blot analysis to compare the levels and phosphorylation state of NF proteins and α-internexin in cerebellar tissue from 47 ET cases versus 26 controls (2:1 ratio). Cases and controls did not differ with respect to the cerebellar levels of NF-light (NF-L), NF-medium (NF-M), NF-heavy (NF-H), or α-internexin. However, SMI-31 levels (i.e., phosphorylated NF-H) and SMI-32 levels (i.e., non-phosphorylated NF-H) were significantly higher in ET cases than controls (1.28±0.47 vs. 1.06±0.32, p=0.02; and 1.38±0.75 vs. 1.00±0.42, p=0.006). Whether the abnormal phosphorylation state that we observed is a cause of defective axonal transport and/or function of NFs in ET is not known. NF abnormalities have been demonstrated in several neurodegenerative diseases. Regardless of whether these protein aggregates are the cause or consequence of these diseases, NF abnormalities have been shown to be an important factor in the cellular disruption observed in several neurodegenerative diseases. Therefore, further analyses of these NF abnormalities and their mechanisms are important to enhance our understanding of disease pathogenesis in ET. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

Characterization and expression of the calpastatin gene in Cyprinus carpio.

PubMed

Chen, W X; Ma, Y

2015-07-03

Calpastatin, an important protein used to regulate meat quality traits in animals, is encoded by the CAST gene. The aim of the present study was to clone the cDNA sequence of the CAST gene and detect the expression of CAST in the tissues of Cyprinus carpio. The cDNA of the C. carpio CAST gene, amplified using rapid amplification of cDNA ends PCR, is 2834 bp in length (accession No. JX275386), contains a 2634-bp open reading frame, and encodes a protein with 877 amino acid residues. The amino acid sequence of the C. carpio CAST gene was 88, 80, and 59% identical to the sequences observed in grass carp, zebrafish, and other fish, respectively. The C. carpio CAST was observed to contain four conserved domains with 54 serine phosphorylation loci, 28 threonine phosphorylation loci, 1 tyrosine phosphorylation loci, and 6 specific protein kinase C phosphorylation loci. The CAST gene showed widespread expression in different tissues of C. carpio. Surprisingly, the relative expression of the CAST transcript in the muscle and heart tissues of C. carpio was significantly higher than in other tissues (P < 0.01).

Dietary Leucine - An Environmental Modifier of Insulin Resistance Acting on Multiple Levels of Metabolism

PubMed Central

Macotela, Yazmin; Emanuelli, Brice; Bång, Anneli M.; Espinoza, Daniel O.; Boucher, Jeremie; Beebe, Kirk; Gall, Walter; Kahn, C. Ronald

2011-01-01

Environmental factors, such as the macronutrient composition of the diet, can have a profound impact on risk of diabetes and metabolic syndrome. In the present study we demonstrate how a single, simple dietary factor—leucine—can modify insulin resistance by acting on multiple tissues and at multiple levels of metabolism. Mice were placed on a normal or high fat diet (HFD). Dietary leucine was doubled by addition to the drinking water. mRNA, protein and complete metabolomic profiles were assessed in the major insulin sensitive tissues and serum, and correlated with changes in glucose homeostasis and insulin signaling. After 8 weeks on HFD, mice developed obesity, fatty liver, inflammatory changes in adipose tissue and insulin resistance at the level of IRS-1 phosphorylation, as well as alterations in metabolomic profile of amino acid metabolites, TCA cycle intermediates, glucose and cholesterol metabolites, and fatty acids in liver, muscle, fat and serum. Doubling dietary leucine reversed many of the metabolite abnormalities and caused a marked improvement in glucose tolerance and insulin signaling without altering food intake or weight gain. Increased dietary leucine was also associated with a decrease in hepatic steatosis and a decrease in inflammation in adipose tissue. These changes occurred despite an increase in insulin-stimulated phosphorylation of p70S6 kinase indicating enhanced activation of mTOR, a phenomenon normally associated with insulin resistance. These data indicate that modest changes in a single environmental/nutrient factor can modify multiple metabolic and signaling pathways and modify HFD induced metabolic syndrome by acting at a systemic level on multiple tissues. These data also suggest that increasing dietary leucine may provide an adjunct in the management of obesity-related insulin resistance. PMID:21731668

GDF‑15 prevents LPS and D‑galactosamine‑induced inflammation and acute liver injury in mice.

PubMed

Li, Min; Song, Kui; Huang, Xiaowen; Fu, Simao; Zeng, Qiyi

2018-06-27

Growth differentiation factor‑15 (GDF‑15) is a transforming growth factor (TGF)‑β superfamily member with a poorly characterized biological activity, speculated to be implicated in several diseases. The present study aimed to determine whether GDF‑15 participates in sepsis‑induced acute liver injury in mice. Lipopolysaccharide (LPS) and D‑galactosamine (D‑GalN) were administered to mice to induce acute liver injury. Survival of mice, histological changes in liver tissue, and levels of inflammatory biomarkers in serum and liver tissue were evaluated following treatment with GDF‑15. The underlying mechanism was investigated by western blotting, ELISA, flow cytometry, and reverse transcription‑quantitative polymerase chain reaction using Kupffer cells. The results demonstrated that GDF‑15 prevented LPS/D‑GalN‑induced death, increase in inflammatory cell infiltration and serum alanine aminotransferase and aspartate aminotransferase activities. In addition, GDF‑15 treatment reduced the production of hepatic malondialdehyde and myeloperoxidase, and attenuated the increase of interleukin (IL)‑6, tumor necrosis factor (TNF)‑α, and IL‑1β expression in serum and liver tissue, accompanied by inducible nitric oxide synthase (iNOS) inactivation in the liver. Similar changes in the expression of inflammatory cytokines, IL‑6, TNF‑α and IL‑1β, and iNOS activation were observed in the Kupffer cells. Further mechanistic experiments revealed that GDF‑15 effectively protected against LPS‑induced nuclear factor (NF)‑κB pathway activation by regulating TGFβ‑activated kinase 1 (TAK1) phosphorylation in Kupffer cells. In conclusion, GDF‑15 reduced the activation of pro‑inflammatory factors, and prevented LPS‑induced liver injury, most likely by disrupting TAK1 phosphorylation, and consequently inhibiting the activation of the NF‑κB pathway in the liver.

Phosphorylated Heat Shock Protein 20 (HSPB6) Regulates Transforming Growth Factor-α-Induced Migration and Invasion of Hepatocellular Carcinoma Cells.

PubMed

Matsushima-Nishiwaki, Rie; Toyoda, Hidenori; Nagasawa, Tomoaki; Yasuda, Eisuke; Chiba, Naokazu; Okuda, Seiji; Maeda, Atsuyuki; Kaneoka, Yuji; Kumada, Takashi; Kozawa, Osamu

2016-01-01

Human hepatocellular carcinoma (HCC) is one of the major malignancies in the world. Small heat shock proteins (HSPs) are reported to play an important role in the regulation of a variety of cancer cell functions, and the functions of small HSPs are regulated by post-translational modifications such as phosphorylation. We previously reported that protein levels of a small HSP, HSP20 (HSPB6), decrease in vascular invasion positive HCC compared with those in the negative vascular invasion. Therefore, in the present study, we investigated whether HSP20 is implicated in HCC cell migration and the invasion using human HCC-derived HuH7 cells. The transforming growth factor (TGF)-α-induced migration and invasion were suppressed in the wild-type-HSP20 overexpressed cells in which phosphorylated HSP20 was detected. Phospho-mimic-HSP20 overexpression reduced the migration and invasion compared with unphosphorylated HSP20 overexpression. Dibutyryl cAMP, which enhanced the phosphorylation of wild-type-HSP20, significantly reduced the TGF-α-induced cell migration of wild-type HSP20 overexpressed cells. The TGF-α-induced cell migration was inhibited by SP600125, a c-Jun N-terminal kinases (JNK) inhibitor. In phospho-mimic-HSP20 overexpressed HuH7 cells, TGF-α-stimulated JNK phosphorylation was suppressed compared with the unphosphorylated HSP20 overexpressed cells. Moreover, the level of phospho-HSP20 protein in human HCC tissues was significantly correlated with tumor invasion. Taken together, our findings strongly suggest that phosphorylated HSP20 inhibits TGF-α-induced HCC cell migration and invasion via suppression of the JNK signaling pathway.

SunRiSE - measuring translation elongation at single-cell resolution by means of flow cytometry.

PubMed

Argüello, Rafael J; Reverendo, Marisa; Mendes, Andreia; Camosseto, Voahirana; Torres, Adrian G; Ribas de Pouplana, Lluis; van de Pavert, Serge A; Gatti, Evelina; Pierre, Philippe

2018-05-31

The rate at which ribosomes translate mRNAs regulates protein expression by controlling co-translational protein folding and mRNA stability. Many factors regulate translation elongation, including tRNA levels, codon usage and phosphorylation of eukaryotic elongation factor 2 (eEF2). Current methods to measure translation elongation lack single-cell resolution, require expression of multiple transgenes and have never been successfully applied ex vivo Here, we show, by using a combination of puromycilation detection and flow cytometry (a method we call 'SunRiSE'), that translation elongation can be measured accurately in primary cells in pure or heterogenous populations isolated from blood or tissues. This method allows for the simultaneous monitoring of multiple parameters, such as mTOR or S6K1/2 signaling activity, the cell cycle stage and phosphorylation of translation factors in single cells, without elaborated, costly and lengthy purification procedures. We took advantage of SunRiSE to demonstrate that, in mouse embryonic fibroblasts, eEF2 phosphorylation by eEF2 kinase (eEF2K) mostly affects translation engagement, but has a surprisingly small effect on elongation, except after proteotoxic stress induction.This article has an associated First Person interview with the first author of the paper. © 2018. Published by The Company of Biologists Ltd.

Estrogen receptor alpha phosphorylation and its functional impact in human breast cancer.

PubMed

Anbalagan, Muralidharan; Rowan, Brian G

2015-12-15

Estrogen receptor α (ERα) is a member of the nuclear receptor superfamily of transcription factors that regulates cell proliferation, differentiation and homeostasis in various tissues. Sustained exposure to estrogen/estradiol (E2) increases the risk of breast, endometrial and ovarian cancers. ERα function is also regulated by phosphorylation through various kinase signaling pathways that will impact various ERα functions including chromatin interaction, coregulator recruitment and gene expression, as well impact breast tumor growth/morphology and breast cancer patient response to endocrine therapy. However, many of the previously characterized ERα phosphorylation sites do not fully explain the impact of receptor phosphorylation on ERα function. This review discusses work from our laboratory toward understanding a role of ERα site-specific phosphorylation in ERα function and breast cancer. The key findings discussed in this review are: (1) the effect of site specific ERα phosphorylation on temporal recruitment of ERα and unique coactivator complexes to specific genes; (2) the impact of stable disruption of ERα S118 and S167 phosphorylation in breast cancer cells on eliciting unique gene expression profiles that culminate in significant effects on breast cancer growth/morphology/migration/invasion; (3) the Src kinase signaling pathway that impacts ERα phosphorylation to alter ERα function; and (4) circadian disruption by light exposure at night leading to elevated ERK1/2 and Src kinase and phosphorylation of ERα, concomitant with tamoxifen resistance in breast tumor models. Results from these studies demonstrate that even changes to single ERα phosphorylation sites can have a profound impact on ERα function in breast cancer. Future work will extend beyond single site phosphorylation analysis toward identification of specific patterns/profiles of ERα phosphorylation under different physiological/pharmacological conditions to understand how common phosphorylation profiles in breast cancer program specific physiological endpoints such as growth, apoptosis, migration/invasion, and endocrine therapy response. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

High intensity aerobic exercise training improves chronic intermittent hypoxia-induced insulin resistance without basal autophagy modulation.

PubMed

Pauly, Marion; Assense, Allan; Rondon, Aurélie; Thomas, Amandine; Dubouchaud, Hervé; Freyssenet, Damien; Benoit, Henri; Castells, Josiane; Flore, Patrice

2017-03-03

Chronic intermittent hypoxia (IH) associated with obstructive sleep apnea (OSA) is a major risk factor for cardiovascular and metabolic diseases (insulin resistance: IR). Autophagy is involved in the pathophysiology of IR and high intensity training (HIT) has recently emerged as a potential therapy. We aimed to confirm IH-induced IR in a tissue-dependent way and to explore the preventive effect of HIT on IR-induced by IH. Thirty Swiss 129 male mice were randomly assigned to Normoxia (N), Intermittent Hypoxia (IH: 21-5% FiO 2 , 30 s cycle, 8 h/day) or IH associated with high intensity training (IH HIT). After 8 days of HIT (2*24 min, 50 to 90% of Maximal Aerobic Speed or MAS on a treadmill) mice underwent 14 days IH or N. We found that IH induced IR, characterized by a greater glycemia, an impaired insulin sensitivity and lower AKT phosphorylation in adipose tissue and liver. Nevertheless, MAS and AKT phosphorylation were greater in muscle after IH. IH associated with HIT induced better systemic insulin sensitivity and AKT phosphorylation in liver. Autophagy markers were not altered in both conditions. These findings suggest that HIT could represent a preventive strategy to limit IH-induced IR without change of basal autophagy.

High intensity aerobic exercise training improves chronic intermittent hypoxia-induced insulin resistance without basal autophagy modulation

PubMed Central

Pauly, Marion; Assense, Allan; Rondon, Aurélie; Thomas, Amandine; Dubouchaud, Hervé; Freyssenet, Damien; Benoit, Henri; Castells, Josiane; Flore, Patrice

2017-01-01

Chronic intermittent hypoxia (IH) associated with obstructive sleep apnea (OSA) is a major risk factor for cardiovascular and metabolic diseases (insulin resistance: IR). Autophagy is involved in the pathophysiology of IR and high intensity training (HIT) has recently emerged as a potential therapy. We aimed to confirm IH-induced IR in a tissue-dependent way and to explore the preventive effect of HIT on IR-induced by IH. Thirty Swiss 129 male mice were randomly assigned to Normoxia (N), Intermittent Hypoxia (IH: 21–5% FiO2, 30 s cycle, 8 h/day) or IH associated with high intensity training (IH HIT). After 8 days of HIT (2*24 min, 50 to 90% of Maximal Aerobic Speed or MAS on a treadmill) mice underwent 14 days IH or N. We found that IH induced IR, characterized by a greater glycemia, an impaired insulin sensitivity and lower AKT phosphorylation in adipose tissue and liver. Nevertheless, MAS and AKT phosphorylation were greater in muscle after IH. IH associated with HIT induced better systemic insulin sensitivity and AKT phosphorylation in liver. Autophagy markers were not altered in both conditions. These findings suggest that HIT could represent a preventive strategy to limit IH-induced IR without change of basal autophagy. PMID:28255159

Oral administration of Lentinus edodes β-glucans ameliorates DSS-induced ulcerative colitis in mice via MAPK-Elk-1 and MAPK-PPARγ pathways.

PubMed

Shi, Limin; Lin, Qinlu; Yang, Tao; Nie, Ying; Li, Xinhua; Liu, Bo; Shen, Junjun; Liang, Ying; Tang, Yiping; Luo, Feijun

2016-11-09

To evaluate the anti-inflammatory effect of β-glucans from Lentinus edodes, and its molecular mechanism, the dextran sulfate sodium salt (DSS) induced colitis model of mice and the LPS-stimulated RAW264.7 cell inflammation model were used in this study. 40 ICR male mice were randomly divided into 4 groups: Control, DSS (DSS treated only), DSS + low-βGs (500 mg kg -1 d -1 ) and DSS + high-βGs (1000 mg kg -1 d -1 ). The body weight of the mice with Lentinus edodes β-glucan supplementation increased significantly compared to the DSS group and the disease activity index (DAI) was improved in both βG-treated groups. Compared with the DSS group, histopathological analysis showed that the infiltration of inflammatory cells of both βG-treated groups decreased significantly in colonic tissues. Furthermore, oral administration of β-glucans decreases the concentration of malondialdehyde (MDA) and myeloperoxidase (MPO) and inhibits the expression of iNOS and several inflammatory factors: TNF-α, IL-1β and IL-6 as well as nitric oxide (NO) of the colonic tissues. The mitogen-activated protein kinase (MAPK) pathway is closely related to the expression of pro-inflammatory factors. In the DSS-induced colitis model and the LPS-stimulated RAW264.7 cell model, βGs inhibited the expression of pro-inflammatory factors and blocked the phosphorylation of JNK/ERK1/2 and p38; βGs also suppress the phosphorylation of Elk-1 at Ser84 and the phosphorylation of PPARγ at Ser112. Altogether, these results suggest that Lentinus edodes βGs could inhibit the DSS-induced ulcerative colitis and decrease inflammatory factor expressions. The molecular mechanism may be involved in suppressing MAPK signaling and inactivation of Elk-1 and activation of PPARγ.

Copy number variations of E2F1: a new genetic risk factor for testicular cancer.

PubMed

Rocca, Maria Santa; Di Nisio, Andrea; Marchiori, Arianna; Ghezzi, Marco; Opocher, Giuseppe; Foresta, Carlo; Ferlin, Alberto

2017-03-01

Testicular germ cell tumor (TGCT) is one of the most heritable forms of cancer. In last years, many evidence suggested that constitutional genetic factors, mainly single nucleotide polymorphisms, can increase its risk. However, the possible contribution of copy number variations (CNVs) in TGCT susceptibility has not been substantially addressed. Indeed, an increasing number of studies have focused on the effect of CNVs on gene expression and on the role of these structural genetic variations as risk factors for different forms of cancer. E2F1 is a transcription factor that plays an important role in regulating cell growth, differentiation, apoptosis and response to DNA damage. Therefore, deficiency or overexpression of this protein might significantly influence fundamental biological processes involved in cancer development and progression, including TGCT. We analyzed E2F1 CNVs in 261 cases with TGCT and 165 controls. We found no CNVs in controls, but 17/261 (6.5%) cases showed duplications in E2F1 Blot analysis demonstrated higher E2F1 expression in testicular samples of TGCT cases with three copies of the gene. Furthermore, we observed higher phosphorylation of Akt and mTOR in samples with E2F1 duplication. Interestingly, normal, non-tumoral testicular tissue in patient with E2F1 duplication showed lower expression of E2F1 and lower AKT/mTOR phosphorylation with respect to adjacent tumor tissue. Furthermore, increased expression of E2F1 obtained in vitro in NTERA-2 testicular cell line induced increased AKT/mTOR phosphorylation. This study suggests for the first time an involvement of E2F1 CNVs in TGCT susceptibility and supports previous preliminary data on the importance of AKT/mTOR signaling pathway in this cancer. © 2017 Society for Endocrinology.

Baicalin ameliorates renal fibrosis via inhibition of transforming growth factor β1 production and downstream signal transduction

PubMed Central

Zheng, Long; Zhang, Chao; Li, Long; Hu, Chao; Hu, Mushuang; Sidikejiang, Niyazi; Wang, Xuanchuan; Lin, Miao; Rong, Ruiming

2017-01-01

Previous studies have demonstrated the potential antifibrotic effects of baicalin in vitro, via examination of 21 compounds isolated from plants. However, its biological activity and underlying mechanisms of action in vivo remain to be elucidated. The present study aimed to evaluate the effect of baicalin on renal fibrosis in vivo, and the potential signaling pathways involved. A unilateral ureteral obstruction (UUO)-induced renal fibrosis model was established using Sprague-Dawley rats. Baicalin was administrated intraperitoneally every 2 days for 10 days. The degree of renal damage and fibrosis was investigated by histological assessment, and detection of fibronectin and collagen I mRNA expression levels. Epithelial-mesenchymal transition (EMT) markers, transforming growth factor-β1 (TGF-β1) levels and downstream phosphorylation of mothers against decapentaplegic 2/3 (Smad2/3) were examined in vivo and in an NRK-52E rat renal tubular cell line in vitro. Baicalin was demonstrated to markedly ameliorate renal fibrosis and suppress EMT, as evidenced by reduced interstitial collagen accumulation, decreased fibronectin and collagen I mRNA expression levels, upregulation of N- and E-cadherin expression levels, and downregulation of α-smooth muscle actin and vimentin expression. Furthermore, baicalin decreased TGF-β1 expression levels in serum and kidney tissue following UUO, and suppressed Smad2/3 phosphorylation in rat kidney tissue. In vitro studies identified that baicalin may inhibit the phosphorylation of Smad2/3 under the same TGF-β1 concentration. In conclusion, baicalin may protect against renal fibrosis, potentially via inhibition of TGF-β1 production and its downstream signal transduction. PMID:28260014

Rebamipide induces the gastric mucosal protective factor, cyclooxygenase-2, via activation of 5'-AMP-activated protein kinase.

PubMed

Lee, Sunyoung; Jeong, Seongkeun; Kim, Wooseong; Kim, Dohoon; Yang, Yejin; Yoon, Jeong-Hyun; Kim, Byung Joo; Min, Do Sik; Jung, Yunjin

2017-01-29

Rebamipide, an amino acid derivative of 2(1H)-quinolinone, has been used for mucosal protection, healing of gastroduodenal ulcers, and treatment of gastritis. Induction of cyclooxygenase (COX)-2, a gastric mucosal protective factor, by rebamipide has been suggested as the major mechanism of the drug action. However, how rebamipide induces COX-2 at the molecular level needs further investigation. In this study, the molecular mechanism underlying the induction of COX-2 by rebamipide was investigated. In gastric carcinoma cells and macrophage cells, rebamipide induced phosphorylation of AMP-activated protein kinase (AMPK), leading to phosphorylation of acetyl-CoA carboxylase (ACC), a substrate of AMPK. The induction of COX-2 by rebamipide was dependent on AMPK activation because compound C, an AMPK inhibitor, abolished COX-2 induction by rebamipide. In a mouse ulcer model, rebamipide protected against hydrochloric acid/ethanol-induced gastric ulcer, and these protective effects were deterred by co-administration of compound C. In parallel, in the gastric tissues, rebamipide increased the phosphorylation AMPK, whereas compound C reduced the levels of COX-2 and phosphorylated ACC, which were increased by rebamipide. Taken together, the activation of AMPK by rebamipide may be a molecular mechanism that contributes to induction of COX-2, probably resulting in protection against gastric ulcers. Copyright © 2016 Elsevier Inc. All rights reserved.

Regulation of the insulin-Akt signaling pathway and glycolysis during dehydration stress in the African clawed frog Xenopus laevis.

PubMed

Wu, Cheng-Wei; Tessier, Shannon N; Storey, Kenneth B

2017-12-01

Estivation is an adaptive stress response utilized by some amphibians during periods of drought in the summer season. In this study, we examine the regulation of the insulin signaling cascade and glycolysis pathway in the African clawed frog Xenopus laevis during the dehydration stress induced state of estivation. We show that in the brain and heart of X. laevis, dehydration reduces the phosphorylation of the insulin growth factor-1 receptor (IGF-1R), and this is followed by similar reductions in the phosphorylation of the Akt and mechanistic target of rapamycin (mTOR) kinase. Interestingly, phosphorylation levels of IGF-1R and mTOR were not affected in the kidney, and phosphorylation levels of P70S6K and the ribosomal S6 protein were elevated during dehydration stress. Animals under estivation are also susceptible to periods of hypoxia, suggesting that glycolysis may also be affected. We observed that protein levels of many glycolytic enzymes remained unchanged during dehydration; however, the hypoxia response factor-1 alpha (HIF-1α) protein was elevated by greater than twofold in the heart during dehydration. Overall, we provide evidence that shows that the insulin signaling pathway in X. laevis is regulated in a tissue-specific manner during dehydration stress and suggests an important role for this signaling cascade in mediating the estivation response.

Cbl downregulation increases RBP4 expression in adipocytes of female mice

PubMed Central

Ameen, Gulizar Issa

2018-01-01

Obesity leads to adipose tissue dysfunction, insulin resistance and diabetes. Adipose tissue produces adipokines that contribute to regulate insulin sensitivity. In turn, insulin stimulates the production and release of some adipokines. Casitas-b-lymphoma proteins (c-Cbl, Cbl-b and Cbl3) are intracellular adaptor signalling proteins that are rapidly phosphorylated by activation of tyrosine kinase receptors. c-Cbl is rapidly phosphorylated by insulin in adipocytes. Here, we tested the hypothesis that Cbl signalling regulates adipokine expression in adipose tissue. We determined the adipokine profile of WAT of Cbl−/− and Cbl+/+ mice in the C57BL6 background. Female Cbl−/− mice exhibited altered expression of adiponectin, leptin and RBP4 in visceral adipose tissue, while no significant changes were seen in male mice. TNFα and IL6 levels were unaffected by Cbl depletion. RBP4 expression was unchanged in liver. Adipose tissue of Cbl−/− animals showed increased basal activation of extracellular regulated kinases (ERK1/2) compared to Cbl+/+. c-Cbl knockdown in 3T3L1 adipocytes also increased basal ERK phosphorylation and RBP4 expression. Inhibition of ERK1/2 phosphorylation in Cbl-depleted 3T3L1 adipocytes or in adipose tissue explants of Cbl−/− mice reduced RBP4 mRNA. 17β-Estradiol increased RBP4 mRNA in adipocytes. Cbl depletion did not change ER expression but increased phosphorylation of ERα at S118, a target site for ERK1/2. ERK1/2 inhibition reduced phosphoER and RBP4 levels. These findings suggest that Cbl contributes to regulate RBP4 expression in adipose of female mice through ERK1/2-mediated activation of ERα. Since Cbl signalling is compromised in diabetes, these data highlight a novel mechanism that upregulates RBP4 locally. PMID:29114012

Heme oxygenase-1/carbon monoxide axis suppresses transforming growth factor-β1-induced growth inhibition by increasing ERK1/2-mediated phosphorylation of Smad3 at Thr-179 in human hepatocellular carcinoma cell lines.

PubMed

Park, Seong Ji; Lee, Seung Koo; Lim, Chae Rin; Park, Hye Won; Liu, Fang; Kim, Seong-Jin; Kim, Byung-Chul

2018-04-06

Heme oxygenase-1 (HO-1) has been implicated in tumor progression, but the underlying molecular mechanisms remain largely unknown. Transforming growth factor-β1 (TGF-β1) exhibits cytostatic and apoptotic effects in hepatocytes and several types of hepatocellular carcinoma (HCC) cell lines, and deregulation of its signaling pathway is linked to hepatic tumorigenesis. In the present study, we observed that HO-1 is expressed at higher levels in HCC tissues than in paired normal tissues. Moreover, TGF-β1-induced cell cycle arrest and up-regulation of cyclin-dependent kinase inhibitors in HCC cell lines were significantly attenuated by overexpression of HO-1 or treatment with tricarbonyldichlororuthenium(II) dimer ([Ru(CO) 3 Cl 2 ] 2 , suggesting an inhibitory role of the HO-1/CO axis in TGF-β signaling to growth inhibition in HCC cell lines. Interestingly, we observed that [Ru(CO) 3 Cl 2 ] 2 inhibits TGF-β1-induced Smad3-dependent reporter activity without affecting its C-terminus phosphorylation, complex formation with Smad4, and nuclear translocation. Additional experiments revealed that HO-1/CO axis selectively induces phosphorylation of Smad3 at Thr-179 residue in the linker region through activation of extracellular signal-activated kinase (ERK) 1/2. Transfection with a phospho-deficient Smad3 (T179A) mutant or treatment with FR180204, a specific inhibitor for ERK1/2, significantly reversed the inhibitory effects of HO-1 and [Ru(CO) 3 Cl 2 ] 2 on cell cycle arrest induced by TGF-β1. These findings for the first time demonstrate that HO-1/CO axis confer resistance of HCC cells to TGF-β growth inhibitory signal by increasing Smad3 phosphorylation at Thr-179 via ERK1/2 pathway. Copyright © 2018 Elsevier Inc. All rights reserved.

Ischemic time impacts biological integrity of phospho-proteins in PI3K/Akt, Erk/MAPK, and p38 MAPK signaling networks.

PubMed

Holzer, Timothy R; Fulford, Angie D; Arkins, Austin M; Grondin, Janet M; Mundy, Christopher W; Nasir, Aejaz; Schade, Andrew E

2011-06-01

Post-translational modifications of proteins, such as phosphorylation, are labile events dynamically regulated by opposing kinase and phosphatase activities. Preanalytical factors, such as ischemic time before fixation, affect these activities and can have a significant impact on the ability to elucidate signaling pathways in tissue. Immunohistochemical analysis of phosphorylated proteins involved in PI3K/Akt, Erk/MAPK, and p38 MAPK signaling networks was performed in human cell line xenografts from lung, brain, ovary, and prostate tumors. In order to replicate real-world practices, the tissues were subjected to ischemic times of 0 (baseline), 1, 4, and 24 hours before fixation in formalin. Two key concepts emerge from this analysis: (1) the stability of different phospho-epitopes within a given tumor type is variable (e.g. phospho-PRAS40 is more labile than phospho-S6 ribosomal protein) and (2) the stability of a given phospho-epitope (e.g. phospho-MAPKAPK2) varies significantly across different tumor types. These results highlight the importance of proper tissue acquisition and rapid fixation to preserve the biological integrity of signal transduction pathways that may guide therapeutic decision making.

STAT3 activation in monocytes accelerates liver cancer progression.

PubMed

Wu, Wen-Yong; Li, Jun; Wu, Zheng-Sheng; Zhang, Chang-Le; Meng, Xiang-Ling

2011-12-05

Signal transducer and activator of transcription 3 (STAT3) is an important transcription factor ubiquitously expressed in different cell types. STAT3 plays an essential role in cell survival, proliferation, and differentiation. Aberrantly hyper-activated STAT3 signaling in cancer cells and in the tumor microenvironment has been detected in a wide variety of human cancers and is considered an important factor for cancer initiation, development, and progression. However, the role of STAT3 activation in monocytes in the development of HCC has not been well understood. Immunohistochemical analysis of phosphorylated STAT3 was performed on tissue microarray from HCC patients. Using a co-culture system in vivo, HCC cell growth was determined by the MTT assay. In vivo experiments were conducted with mice given diethylinitrosamine (DEN), which induces HCC was used to investigate the role of STAT3 expression in monocytes on tumor growth. Real-time PCR was used to determine the expression of cell proliferation and cell arrest associated genes in the tumor and nontumor tissue from liver. Phosphorylated STAT3 was found in human hepatocellular carcinoma tissue samples and was expressed in tumor cells and also in monocytes. Phosphorylated STAT3 expression in monocyte was significantly correlated to advanced clinical stage of HCC and a poor prognosis. Using a co-culture system in vivo, monocytes promoted HCC cell growth via the IL-6/STAT3 signaling pathway. The STAT3 inhibitor, NSC 74859, significantly suppressed tumor growth in vivo in mice with diethylinitrosamine (DEN)-induced HCC. In this animal model, blockade of STAT3 with NSC 74859 induced tumor cell apoptosis, while inhibiting both tumor cells and monocytes proliferation. Furthermore, NSC 74859 treatment suppressed cancer associated inflammation in DEN-induce HCC. Our data suggest constitutively activated STAT3 monocytes promote liver tumorigenesis in clinical patients and animal experiments. Thus, STAT3 in tumor infiltrating inflammatory cells may an attractive target for liver cancer therapy.

Renin-angiotensin system inhibition ameliorates CCl4-induced liver fibrosis in mice through the inactivation of nuclear transcription factor kappa B.

PubMed

Saber, Sameh; Mahmoud, Amr A A; Helal, Noha S; El-Ahwany, Eman; Abdelghany, Rasha H

2018-06-01

Therapeutic interventions for liver fibrosis are still limited due to the complicated molecular pathogenesis. Renin-angiotensin system (RAS) seems to contribute to the development of hepatic fibrosis. Therefore, we aimed to examine the effect of RAS inhibition on CCl 4 -induced liver fibrosis. Mice were treated with silymarin (30 mg·kg -1 ), perindopril (1 mg·kg -1 ), fosinopril (2 mg·kg -1 ), or losartan (10 mg·kg -1 ). The administration of RAS inhibitors improved liver histology and decreased protein expression of alpha smooth muscle actin (α-SMA) and hepatic content of hydroxyproline. These effects found to be mediated via inactivation of nuclear transcription factor kappa B (NFκB) pathway by the inhibition of NFκB p65 phosphorylation at the Ser536 residue and phosphorylation-induced degradation of nuclear factor kappa-B inhibitor alpha (NFκBia) subsequently inhibited NFκB-induced TNF-α and TGF-β1, leading to lower levels of tissue inhibitor of metalloproteinase-1 (TIMP-1) and vascular endothelial growth factor (VEGF). We concluded that the tissue affinity of the angiotensin converting enzyme inhibitors (ACEIs) has no impact on its antifibrotic activity and that interfering the RAS either through the inhibition of ACE or the blockade of AT1R has the same therapeutic benefit. These results suggest RAS inhibitors as promising candidates for further clinical trials in the management of hepatic fibrosis.

Expression pattern and phosphorylation status of Smad2/3 in different subtypes of human first trimester trophoblast.

PubMed

Haider, S; Kunihs, V; Fiala, C; Pollheimer, J; Knöfler, M

2017-09-01

TGF-β superfamily members are thought to play a pivotal role in placental development and differentiation. However, their downstream effectors, the Smad transcription factors, have been poorly investigated in human trophoblasts. Expression and localisation of the canonical TGF-β targets Smad2/3 and their regulators (Smad4 and Smad7) were investigated in first trimester placenta and purified cytotrophoblast (CTB) subtypes using immunofluorescence, western blotting and qPCR. Canonical and non-canonical activation was analysed in nuclear/cytoplasmic extracts of trophoblast subtypes as well as in tissue sections using antibodies against Smad2/3, phosphorylated either at the C-terminus (pSmad2C/3C) or in their linker regions (pSmad2L/3L). Smad phosphorylation was also examined in differentiating extravillous trophoblasts (EVTs) in the absence or presence of decidual stromal cell (DSC)-conditioned medium. Smad2, Smad4 and Smad7 protein were uniformly expressed between 6th and 12th week placentae and the different isolated CTB subtypes. Activated pSmad2L was mainly detected in nuclei and cytoplasm of villous CTBs, whereas pSmad2C was absent from these cells. In contrast, pSmad2C could be detected in the cytoplasm of cell column trophoblasts and in the cytoplasm/nuclei of EVTs. Smad3 and its phosphorylated forms pSmad3C and pSmad3L specifically localised to EVT nuclei. During EVT differentiation autocrine activation of pSmad2C/3C and pSmad3L was observed. DSC-conditioned medium further increased Smad2/3 phosphorylation in EVTs. The lack of pSmad2C in villous CTBs suggests that other mitogens than TGF-β could promote Smad2 linker phosphorylation under homeostatic conditions. Whereas autocrine signalling activates Smad2/3 in differentiating EVTs, paracrine factors contribute to Smad phosphorylation in these cells. Copyright © 2017 Elsevier Ltd. All rights reserved.

Insulin signaling in various equine tissues under basal conditions and acute stimulation by intravenously injected insulin.

PubMed

Warnken, Tobias; Brehm, Ralph; Feige, Karsten; Huber, Korinna

2017-10-01

The aim of the study was to analyze key proteins of the equine insulin signaling cascade and their extent of phosphorylation in biopsies from muscle tissue (MT), liver tissue (LT), and nuchal AT, subcutaneous AT, and retroperitoneal adipose tissues. This was investigated under unstimulated (B1) and intravenously insulin stimulated (B2) conditions, which were achieved by injection of insulin (0.1 IU/kg bodyweight) and glucose (150 mg/kg bodyweight). Twelve warmblood horses aged 15 ± 6.8 yr (yr), weighing 559 ± 79 kg, and with a mean body condition score of 4.7 ± 1.5 were included in the study. Key proteins of the insulin signaling cascade were semiquantitatively determined using Western blotting. Furthermore, modulation of the cascade was assessed. The basal expression of the proteins was only slightly influenced during the experimental period. Insulin induced a high extent of phosphorylation of insulin receptor in LT (P < 0.01) but not in MT. Protein kinase B and mechanistic target of rapamycin expressed a higher extent of phosphorylation in all tissues in B2 biopsies. Adenosine monophosphate protein kinase, as a component related to insulin signaling, expressed enhanced phosphorylation in MT (P < 0.05) and adipose tissues (nuchal AT P < 0.05; SCAT P < 0.01; retroperitoneal adipose tissue P < 0.05), but not in LT at B2. Tissue-specific variations in the acute response of insulin signaling to intravenously injected insulin were observed. In conclusion, insulin sensitivity in healthy horses is based on a complex concerted action of different tissues by their variations in the molecular response to insulin. Copyright © 2017 Elsevier Inc. All rights reserved.

Phosphorylation of nuclear factor erythroid 2-like 2 (NFE2L2) in mammary tissue of Holstein cows during the periparturient period is associated with mRNA abundance of antioxidant gene networks.

PubMed

Han, L Q; Zhou, Z; Ma, Y; Batistel, F; Osorio, J S; Loor, J J

2018-04-18

Changes in the production of reactive oxygen species in the mammary gland of dairy cows during the periparturient period could lead to oxidative stress and potentially impair mammary function. Phosphorylation of the transcription factor nuclear factor erythroid 2-like 2 (NFE2L2), also known as nuclear factor-E2-related factor 2, controls mRNA abundance of genes encoding antioxidant proteins and enzymes. The hypothesis was that NFE2L2 phosphorylation status and target gene mRNA abundance in the mammary gland of dairy cows is altered around parturition. Total NFE2L2 protein, phosphorylated protein (p-NFE2L2), and ratio of p-NFE2L2 to NFE2L2 along with mRNA abundance of 24 genes related to the NFE2L2 signaling pathway, apoptosis, and cell proliferation were measured in mammary tissue samples from Holstein cows at -30, 1, 15, and 30 d relative to parturition. Although total NFE2L2 protein abundance did not differ, p-NFE2L2 and p-NFE2L2-to-NFE2L2 ratio were greater after parturition. The upregulation of DNA damage inducible transcript 3 (DDIT3) postpartum indicated a localized oxidative stress state. Among genes evaluated, thioredoxin (TXN), glutathione peroxidase 1 (GPX1), and glutathione S-transferase mu 1 (GSTM1) had the highest (37.1, 15.1, and 4.8% of total mRNA measured, respectively) abundance. The mRNA abundance of various target genes with detoxifying enzymatic functions and free radical scavenging activities [glutamate-cysteine ligase catalytic subunit (GCLC); glutathione reductase (GSR); ferrochelatase (FECH); TXN; thioredoxin reductase 1 (TXNRD1); and NAD(P)H quinone dehydrogenase 1 (NQO1)] were consistently upregulated (linear effect of time) as parturition approached and lactation began. Among the transcription regulators, NFE2L2 had the highest mRNA abundance (7.3% of total mRNA measured). Abundance of NFE2L2 and other transcription factors [nuclear factor kappa B subunit 1 (NFKB1), retinoid X receptor α (RXRA), and mitogen-activated protein kinase 14 (MAPK14)] were upregulated (linear effect of time) from -30 d to 30 d relative to parturition. Overall, NFE2L2 phosphorylation and downstream signaling leading to postpartal upregulation of genes associated with oxidative stress and inflammation in the mammary gland seem to be key components of normal cellular function to maintain proper redox homeostasis. However, if the longitudinal increases in mRNA and protein abundance of these antioxidant mechanisms are a reflection of cellular oxidative stress, then the likelihood of protein and DNA damage would be greater and might be one factor compromising cell viability and potentially lactation persistency. The actual cues coordinating these molecular responses remain to be determined. Copyright © 2018 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Stromal cell-derived factor 1 protects human periodontal ligament stem cells against hydrogen peroxide-induced apoptosis.

PubMed

Feng, Yimiao; Fu, Xiaohui; Lou, Xintian; Fu, Baiping

2017-10-01

Periodontal ligament stem cells (PDLSCs) are considered a promising cell source for dental tissue regeneration. Stromal cell-derived factor 1 [SDF‑1, also known as chemokine (C‑X‑C motif) ligand 12] is regarded as a critical cytokine involved in stem/progenitor cell chemotaxis and homing during tissue regeneration. The present study described a previously unsuspected role for SDF‑1 in the protection of PDLSCs against oxidative stress‑induced apoptosis. In the present study, apoptosis was induced by exposure of PDLSCs to various concentrations of H2O2 for 12 h, following which cell viability was assessed, and cleaved caspase‑3 and ‑9 expression levels were evaluated. To investigate the potential mechanism underlying this protection, the protein expression levels of total and phosphorylated extracellular signal‑regulated kinase (ERK), a key protein of the mitogen‑activated protein kinase (MAPK) signaling pathway, were examined. The results of the present study revealed that SDF‑1 pretreatment increased cell viability following H2O2 administration, and downregulated protein expression levels of activated caspase‑3 and ‑9. Furthermore, treatment with SDF‑1 increased the phosphorylation of ERK. The protective effect of SDF‑1 was partially inhibited by treatment with PD98059, a MAPK/ERK inhibitor, which decreased cell viability. The results of the present study suggested that SDF‑1 treatment is a potential strategy to improve the survival of PDLSCs, which may be beneficial for dental tissue regeneration.

Bud detachment in hydra requires activation of fibroblast growth factor receptor and a Rho–ROCK–myosin II signaling pathway to ensure formation of a basal constriction

PubMed Central

Holz, Oliver; Apel, David; Steinmetz, Patrick; Lange, Ellen; Hopfenmüller, Simon; Ohler, Kerstin; Sudhop, Stefanie

2017-01-01

Background: Hydra propagates asexually by exporting tissue into a bud, which detaches 4 days later as a fully differentiated young polyp. Prerequisite for detachment is activation of fibroblast growth factor receptor (FGFR) signaling. The mechanism which enables constriction and tissue separation within the monolayered ecto‐ and endodermal epithelia is unknown. Results: Histological sections and staining of F‐actin by phalloidin revealed conspicuous cell shape changes at the bud detachment site indicating a localized generation of mechanical forces and the potential enhancement of secretory functions in ectodermal cells. By gene expression analysis and pharmacological inhibition, we identified a candidate signaling pathway through Rho, ROCK, and myosin II, which controls bud base constriction and rearrangement of the actin cytoskeleton. Specific regional myosin phosphorylation suggests a crucial role of ectodermal cells at the detachment site. Inhibition of FGFR, Rho, ROCK, or myosin II kinase activity is permissive for budding, but represses myosin phosphorylation, rearrangement of F‐actin and constriction. The young polyp remains permanently connected to the parent by a broad tissue bridge. Conclusions: Our data suggest an essential role of FGFR and a Rho‐ROCK‐myosin II pathway in the control of cell shape changes required for bud detachment. Developmental Dynamics 246:502–516, 2017. © 2017 The Authors Developmental Dynamics published by Wiley Periodicals, Inc. on behalf of American Association of Anatomists PMID:28411398

Bud detachment in hydra requires activation of fibroblast growth factor receptor and a Rho-ROCK-myosin II signaling pathway to ensure formation of a basal constriction.

PubMed

Holz, Oliver; Apel, David; Steinmetz, Patrick; Lange, Ellen; Hopfenmüller, Simon; Ohler, Kerstin; Sudhop, Stefanie; Hassel, Monika

2017-07-01

Hydra propagates asexually by exporting tissue into a bud, which detaches 4 days later as a fully differentiated young polyp. Prerequisite for detachment is activation of fibroblast growth factor receptor (FGFR) signaling. The mechanism which enables constriction and tissue separation within the monolayered ecto- and endodermal epithelia is unknown. Histological sections and staining of F-actin by phalloidin revealed conspicuous cell shape changes at the bud detachment site indicating a localized generation of mechanical forces and the potential enhancement of secretory functions in ectodermal cells. By gene expression analysis and pharmacological inhibition, we identified a candidate signaling pathway through Rho, ROCK, and myosin II, which controls bud base constriction and rearrangement of the actin cytoskeleton. Specific regional myosin phosphorylation suggests a crucial role of ectodermal cells at the detachment site. Inhibition of FGFR, Rho, ROCK, or myosin II kinase activity is permissive for budding, but represses myosin phosphorylation, rearrangement of F-actin and constriction. The young polyp remains permanently connected to the parent by a broad tissue bridge. Our data suggest an essential role of FGFR and a Rho-ROCK-myosin II pathway in the control of cell shape changes required for bud detachment. Developmental Dynamics 246:502-516, 2017. © 2017 The Authors Developmental Dynamics published by Wiley Periodicals, Inc. on behalf of American Association of Anatomists. © 2017 The Authors Developmental Dynamics published by Wiley Periodicals, Inc. on behalf of American Association of Anatomists.

Quercetin suppresses immune cell accumulation and improves mitochondrial gene expression in adipose tissue of diet‐induced obese mice

PubMed Central

Takahashi, Yumiko; Sakurai, Mutsumi; Akimoto, Yukari; Tsushida, Tojiro; Oike, Hideaki; Ippoushi, Katsunari

2015-01-01

Scope To examine the effect of dietary quercetin on the function of epididymal adipose tissue (EAT) in Western diet‐induced obese mice. Methods and results C57BL/6J mice were fed a control diet; a Western diet high in fat, cholesterol, and sucrose; or the same Western diet containing 0.05% quercetin for 18 weeks. Supplementation with quercetin suppressed the increase in the number of macrophages, the decrease in the ratio of CD4+ to CD8+ T cells in EAT, and the elevation of plasma leptin and tumor necrosis factor α levels in mice fed the Western diet. Comprehensive gene expression analysis revealed that quercetin suppressed gene expression associated with the accumulation and activation of immune cells, including macrophages and lymphocytes in EAT. It also improved the expression of the oxidative stress‐sensitive transcription factor NFκB, NADPH oxidases, and antioxidant enzymes. Quercetin markedly increased gene expression associated with mitochondrial oxidative phosphorylation and mitochondrial DNA content. Conclusion Quercetin most likely universally suppresses the accumulation and activation of immune cells, including antiinflammatory cells, whereas it specifically increased gene expression associated with mitochondrial oxidative phosphorylation. Suppression of oxidative stress and NFκB activity likely contributed to the prevention of the accumulation and activation of immune cells and resulting chronic inflammation. PMID:26499876

Insulin response in individual tissues of control and gold thioglucose-obese mice in vivo with (1-/sup 14/C)2-deoxyglucose

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cooney, G.J.; Astbury, L.D.; Williams, P.F.

The dose-response characteristics of several glucose-utilizing tissues (brain, heart, white adipose tissue, brown adipose tissue, and quadriceps muscle) to a single injection of insulin have been compared in control mice and mice made obese with a single injection of gold thioglucose (GTG). Tissue content of (1-/sup 14/C)2-deoxyglucose 6-phosphate and blood disappearance rate of (1-/sup 14/C)2-deoxyglucose (2-DG) were measured at nine different insulin doses and used to calculate rates of 2-DG uptake and phosphorylation in tissues from control and obese mice. The insulin sensitivity of tissues reflected in the ED50 of insulin response varied widely, and brown adipose tissue was themore » most insulin-sensitive tissue studied. In GTG-obese mice, heart, quadriceps, and brown adipose tissue were insulin resistant (demonstrated by increased ED50), whereas in white adipose tissue, 2-DG phosphorylation was more sensitive to insulin. Brain 2-DG phosphorylation was insulin independent in control and obese animals. The largest decrease in insulin sensitivity in GTG-obese mice was observed in brown adipose tissue. The loss of diet-induced thermogenesis in brown adipose tissue as a result of the hypothalamic lesion in GTG-obese mice could be a major cause of insulin resistance in brown adipose tissue. Because brown adipose tissue can make a major contribution to whole-body glucose utilization, insulin resistance in this tissue may have a significant effect on whole-animal glucose homeostasis in GTG-obese mice.« less

Fimasartan Ameliorates Nonalcoholic Fatty Liver Disease through PPARδ Regulation in Hyperlipidemic and Hypertensive Conditions

PubMed Central

Jang, Yoo-Na; Han, Yoon-Mi; Kim, Hyun-Min; Jeong, Jong-Min

2017-01-01

To investigate the effects of fimasartan on nonalcoholic fatty liver disease in hyperlipidemic and hypertensive conditions, the levels of biomarkers related to fatty acid metabolism were determined in HepG2 and differentiated 3T3-L1 cells treated by high fatty acid and liver and visceral fat tissue samples of spontaneously hypertensive rats (SHRs) given high-fat diet. In HepG2 cells and liver tissues, fimasartan was shown to increase the protein levels of peroxisome proliferator-activated receptor delta (PPARδ), phosphorylated 5′ adenosine monophosphate-activated protein kinase (p-AMPK), phosphorylated acetyl-CoA carboxylase (p-ACC), malonyl-CoA decarboxylase (MCD), medium chain acyl-CoA dehydrogenase (MCAD), and peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1α), and it led to a decrease in the protein levels of 11 beta-hydroxysteroid dehydrogenase 1 (11β-HSDH1), fatty acid synthase (FAS), and tumor necrosis factor-alpha (TNF-α). Fimasartan decreased lipid contents in HepG2 and differentiated 3T3-L1 cells and liver tissues. In addition, fimasartan increased the adiponectin level in visceral fat tissues. The antiadipogenic effects of fimasartan were offset by PPARδ antagonist (GSK0660). Consequently, fimasartan ameliorates nonalcoholic fatty liver disease mainly through the activation of oxidative metabolism represented by PPARδ-AMPK-PGC-1α pathway. PMID:28386270

Delayed Administration of Pyroglutamate Helix B Surface Peptide (pHBSP), a Novel Nonerythropoietic Analog of Erythropoietin, Attenuates Acute Kidney Injury

PubMed Central

Patel, Nimesh S A; Kerr-Peterson, Hannah L; Brines, Michael; Collino, Massimo; Rogazzo, Mara; Fantozzi, Roberto; Wood, Elizabeth G; Johnson, Florence L; Yaqoob, Muhammad M; Cerami, Anthony; Thiemermann, Christoph

2012-01-01

In preclinical studies, erythropoietin (EPO) reduces ischemia-reperfusion–associated tissue injury (for example, stroke, myocardial infarction, acute kidney injury, hemorrhagic shock and liver ischemia). It has been proposed that the erythropoietic effects of EPO are mediated by the classic EPO receptor homodimer, whereas the tissue-protective effects are mediated by a hetero-complex between the EPO receptor monomer and the β-common receptor (termed “tissue-protective receptor”). Here, we investigate the effects of a novel, selective-ligand of the tissue-protective receptor (pyroglutamate helix B surface peptide [pHBSP]) in a rodent model of acute kidney injury/dysfunction. Administration of pHBSP (10 μg/kg intraperitoneally [i.p.] 6 h into reperfusion) or EPO (1,000 IU/kg i.p. 4 h into reperfusion) to rats subjected to 30 min ischemia and 48 h reperfusion resulted in significant attenuation of renal and tubular dysfunction. Both pHBSP and EPO enhanced the phosphorylation of Akt (activation) and glycogen synthase kinase 3β (inhibition) in the rat kidney after ischemia-reperfusion, resulting in prevention of the activation of nuclear factor-κB (reduction in nuclear translocation of p65). Interestingly, the phosphorylation of endothelial nitric oxide synthase was enhanced by EPO and, to a much lesser extent, by pHBSP, suggesting that the signaling pathways activated by EPO and pHBSP may not be identical. PMID:22415011

PINK1-Mediated Phosphorylation of Parkin Boosts Parkin Activity in Drosophila

PubMed Central

Shiba-Fukushima, Kahori; Inoshita, Tsuyoshi; Hattori, Nobutaka; Imai, Yuzuru

2014-01-01

Two genes linked to early onset Parkinson's disease, PINK1 and Parkin, encode a protein kinase and a ubiquitin-ligase, respectively. Both enzymes have been suggested to support mitochondrial quality control. We have reported that Parkin is phosphorylated at Ser65 within the ubiquitin-like domain by PINK1 in mammalian cultured cells. However, it remains unclear whether Parkin phosphorylation is involved in mitochondrial maintenance and activity of dopaminergic neurons in vivo. Here, we examined the effects of Parkin phosphorylation in Drosophila, in which the phosphorylation residue is conserved at Ser94. Morphological changes of mitochondria caused by the ectopic expression of wild-type Parkin in muscle tissue and brain dopaminergic neurons disappeared in the absence of PINK1. In contrast, phosphomimetic Parkin accelerated mitochondrial fragmentation or aggregation and the degradation of mitochondrial proteins regardless of PINK1 activity, suggesting that the phosphorylation of Parkin boosts its ubiquitin-ligase activity. A non-phosphorylated form of Parkin fully rescued the muscular mitochondrial degeneration due to the loss of PINK1 activity, whereas the introduction of the non-phosphorylated Parkin mutant in Parkin-null flies led to the emergence of abnormally fused mitochondria in the muscle tissue. Manipulating the Parkin phosphorylation status affected spontaneous dopamine release in the nerve terminals of dopaminergic neurons, the survivability of dopaminergic neurons and flight activity. Our data reveal that Parkin phosphorylation regulates not only mitochondrial function but also the neuronal activity of dopaminergic neurons in vivo, suggesting that the appropriate regulation of Parkin phosphorylation is important for muscular and dopaminergic functions. PMID:24901221

Expression and activity of the 5'-adenosine monophosphate-activated protein kinase pathway in selected tissues during chicken embryonic development.

PubMed

Proszkowiec-Weglarz, M; Richards, M P

2009-01-01

The 5'-adenosine monophosphate-activated protein kinase (AMPK) is a highly conserved serine-threonine protein kinase and a key part of a kinase-signaling cascade that senses cellular energy status (adenosine monophosphate:adenosine triphosphate ratio) and acts to maintain energy homeostasis by coordinately regulating energy-consuming and energy-generating metabolic pathways. The objective of this study was to investigate aspects of the AMPK pathway in the liver, brain, breast muscle, and heart from d 12 of incubation through hatch in chickens. We first determined mRNA and protein expression profiles for a major upstream AMPK kinase, LKB1, which is known to activate (phosphorylate) AMPK in response to increases in the adenosine monophosphate:adenosine triphosphate ratio. Expression of LKB1 protein was greatest in the brain, which demonstrated tissue-specific patterns for phosphorylation. Next, AMPK subunit mRNA and protein expression profiles were determined. Significant changes in AMPK subunit mRNA expression occurred in all tissues from d 12 of incubation to hatch. Differences in the levels of active (phosphorylated) AMPK as well as alpha and beta subunit proteins were observed in all 4 tissues during embryonic development. Finally, we determined the protein level and phosphorylation status of an important downstream target for AMPK, acetyl-coenzyme A carboxylase. The expression of acetyl-co-enzyme A carboxylase and phosphorylated acetyl-coenzyme A was greater in the brain than the liver, but was undetectable by Western blotting in the breast muscle and heart throughout the period of study. Together, our results are the first to demonstrate the expression and activity of the AMPK pathway in key tissues during the transition from embryonic to posthatch development in chickens.

14-3-3 proteins regulate desmosomal adhesion via plakophilins.

PubMed

Rietscher, Katrin; Keil, René; Jordan, Annemarie; Hatzfeld, Mechthild

2018-05-22

Desmosomes are essential for strong intercellular adhesion and are abundant in tissues exposed to mechanical strain. At the same time, desmosomes need to be dynamic to allow for remodeling of epithelia during differentiation or wound healing. Phosphorylation of desmosomal plaque proteins appears to be essential for desmosome dynamics. However, the mechanisms of how context-dependent post-translational modifications regulate desmosome formation, dynamics or stability are incompletely understood. Here, we show that growth factor signaling regulates the phosphorylation-dependent association of plakophilins 1 and 3 (PKP1 and PKP3) with 14-3-3 protein isoforms, and uncover unique and partially antagonistic functions of members of the 14-3-3 family in the regulation of desmosomes. 14-3-3γ associated primarily with cytoplasmic PKP1 phosphorylated at S155 and destabilized intercellular cohesion of keratinocytes by reducing its incorporation into desmosomes. In contrast, 14-3-3σ (also known as stratifin, encoded by SFN ) interacted preferentially with S285-phosphorylated PKP3 to promote its accumulation at tricellular contact sites, leading to stable desmosomes. Taken together, our study identifies a new layer of regulation of intercellular adhesion by 14-3-3 proteins. © 2018. Published by The Company of Biologists Ltd.

Liver tumor formation by a mutant retinoblastoma protein in the transgenic mice is caused by an upregulation of c-Myc target genes.

PubMed

Wang, Bo; Hikosaka, Keisuke; Sultana, Nishat; Sharkar, Mohammad Tofael Kabir; Noritake, Hidenao; Kimura, Wataru; Wu, Yi-Xin; Kobayashi, Yoshimasa; Uezato, Tadayoshi; Miura, Naoyuki

2012-01-06

The retinoblastoma (Rb) tumor suppressor encodes a nuclear phosphoprotein that regulates cellular proliferation, apoptosis and differentiation. In order to adapt itself to these biological functions, Rb is subjected to modification cycle, phosphorylation and dephosphorylation. To directly determine the effect of phosphorylation-resistant Rb on liver development and function, we generated transgenic mice expressing phosphorylation-resistant human mutant Rb (mt-Rb) under the control of the rat hepatocyte nuclear factor-1 gene promoter/enhancer. Expression of mt-Rb in the liver resulted in macroscopic neoplastic nodules (adenomas) with ∼50% incidence within 15 months old. Interestingly, quantitative reverse transcriptase-PCR analysis showed that c-Myc was up-regulated in the liver of mt-Rb transgenic mice irrespective of having tumor tissues or no tumor. In tumor tissues, several c-Myc target genes, Foxm1, c-Jun, c-Fos, Bmi1 and Skp2, were also up-regulated dramatically. We determined whether mt-Rb activated the Myc promoter in the HTP9 cells and demonstrated that mt-Rb acted as an inhibitor of wild-type Rb-induced repression on the Myc promoter. Our results suggest that continued upregulation of c-Myc target genes promotes the liver tumor formation after about 1 year of age. Copyright © 2011 Elsevier Inc. All rights reserved.

Isoliquiritigenin Attenuates Adipose Tissue Inflammation in vitro and Adipose Tissue Fibrosis through Inhibition of Innate Immune Responses in Mice.

PubMed

Watanabe, Yasuharu; Nagai, Yoshinori; Honda, Hiroe; Okamoto, Naoki; Yamamoto, Seiji; Hamashima, Takeru; Ishii, Yoko; Tanaka, Miyako; Suganami, Takayoshi; Sasahara, Masakiyo; Miyake, Kensuke; Takatsu, Kiyoshi

2016-03-15

Isoliquiritigenin (ILG) is a flavonoid derived from Glycyrrhiza uralensis and potently suppresses NLRP3 inflammasome activation resulting in the improvement of diet-induced adipose tissue inflammation. However, whether ILG affects other pathways besides the inflammasome in adipose tissue inflammation is unknown. We here show that ILG suppresses adipose tissue inflammation by affecting the paracrine loop containing saturated fatty acids and TNF-α by using a co-culture composed of adipocytes and macrophages. ILG suppressed inflammatory changes induced by the co-culture through inhibition of NF-κB activation. This effect was independent of either inhibition of inflammasome activation or activation of peroxisome proliferator-activated receptor-γ. Moreover, ILG suppressed TNF-α-induced activation of adipocytes, coincident with inhibition of IκBα phosphorylation. Additionally, TNF-α-mediated inhibition of Akt phosphorylation under insulin signaling was alleviated by ILG in adipocytes. ILG suppressed palmitic acid-induced activation of macrophages, with decreasing the level of phosphorylated Jnk expression. Intriguingly, ILG improved high fat diet-induced fibrosis in adipose tissue in vivo. Finally, ILG inhibited TLR4- or Mincle-stimulated expression of fibrosis-related genes in stromal vascular fraction from obese adipose tissue and macrophages in vitro. Thus, ILG can suppress adipose tissue inflammation by both inflammasome-dependent and -independent manners and attenuate adipose tissue fibrosis by targeting innate immune sensors.

Bone marrow stromal cells promote neuroplasticity of cerebral ischemic rats via a phosphorylated CRMP2-mediated mechanism.

PubMed

He, Xiang; Jiang, Ling; Dan, Qi-Qin; Lv, Qiang; Hu, Yue; Liu, Jia; Wang, Shu-Fen; Wang, Ting-Hua

2017-03-01

Collapsin response mediator protein 2 (CRMP2), an important protein involved in axonal growth and the maintenance of neuronal membrane integrity, has proved to be altered in nervous system diseases. This study was aimed to investigate the role of CRMP2 in bone marrow stromal cells (BMSCs) treating rats with cerebral ischemia. BMSCs were isolated from shaft of the femurs, tibiae, and humeri and were intra-carotid administrated immediately after middle cerebral artery occlusion (MCAO). Modified Neurological Severity Scores (mNSS) was conducted at 3, 7, 14dpo and the electrophysiologic evaluation was evaluated at 14dpo. Then all rats were sacrificed and brain tissues were harvested for RT-PCR, Western blot and Immunohistochemistry analysis. We found BMSCs treatment significantly improved the neurobehavioral performance impaired by ischemic brain injury, accompanied with the notably increasing levels of Synaptophysin (SYP) and Growth associated protein 43 (GAP43). We also found the protein level of phosphorylated CRMP2 (p-CRMP2) and phosphorylation-mediated protein including Glycogen synthase kinase 3 Beta (GSK3β), Cyclin-dependent kinase 5 (CDK5) were dramatically downregulated in ischemic rats following BMSCs transplant. Furthermore, the GSK3β-mediated factors including neurotrophic and signaling factors were all significantly upregulated in BMSCs-treated group. On the basis of these findings, we suggest that the neuroplasticity effect of BMSCs on cerebral ischemia may be associated with the phosphorylated modulation of CRMP2. Copyright © 2016 Elsevier B.V. All rights reserved.

Human neutrophil elastase and collagenase sequestration with phosphorylated cotton wound dressings.

PubMed

Edwards, J Vincent; Howley, Phyllis S

2007-11-01

The design and preparation of wound dressings that redress the protease imbalance in chronic wounds is an important goal of wound healing and medical materials science. Chronic wounds contain high levels of tissue and cytokine-destroying proteases including matrix metalloprotease and neutrophil elastase. Thus, the lowering of excessive protease levels in the wound environment by wound dressing sequestration prevents the breakdown of extracellular matrix proteins and growth factors necessary for wound healing. Phosphorylated cotton wound dressings were prepared to target sequestration of proteases from chronic wound exudate through a cationic uptake binding mechanism involving salt bridge formation of the positively charged amino acid side chains of proteases with the phosphate counterions of the wound dressing fiber. Dressings were prepared by applying sodium hexametaphosphate and diammonium phosphate in separate formulations to cotton gauze by pad/dry/cure methods. Phosphorylated cotton dressings were assessed for their ability to lower elastase and collagenase activity. The phosphorylated cotton dressings lowered elastase and collagenase activity 40-80% more effectively than the untreated cotton wound dressings under conditions that mimic chronic wound exudate. Efficacy of the phosphorylated cotton was found to be related to the level of phosphorylation and a lower pH due to protonated phosphate at the surface of the dressing. The capacity of the modified gauze to sequester continued elastase secretions similar to that found in a chronic wound over a 24-h period was retained within a 80% retention of elastase sequestration and was dose-dependent. Copyright (c) 2007 Wiley Periodicals, Inc.

[Mechanism of action for oligomeric proanthocyaniclins in pava qnat-induced acute lung injury].

PubMed

Liu, P; Zhou, Y S; Qin, Y L; Li, L; Liu, Y; Xu, B; Huang, K; Ji, C C; Lin, F; Wang, Y G; Li, K; Chen, S H; Shao, L F; Mu, J S

2017-11-20

Objective: The present study was designed to evaluate the protective effects of oligomeric proanthocyanidins (OPC) in mice exposed to paraquat (PQ) , and to explore the molecular mechanism. Methods: Four experimental groups were designed. 10 BALB/c mice were intraperitoneally injected with normal saline) . PQ group: 10 BALB/c mice were intraperitoneally injected with PQ (100 mg/kg) . PQ+OPC group: 10 BALB/c mice were administered with OPC (100 mg/kg) for 1 h before PQ (100 mg/kg) expo-sure. OPC group: 10 BALB/c mice were intraperitoneally injected with OPC (100 mg/kg) . The peripheral blood samples or lung tissue samples were collected at the designed time points for measuring the levels of oxi-dative stress indicators, the related protein levels of nuclear factor-kappa B (NF-κB) pathway and nuclear fac-tor erythroid related factor-2 (Nrf2) pathway. Results: Compared with the control group, the level of reactive oxygen species (ROS) , the content of malondialdehyde (MDA) in the PQ group were significantly induced, and the activity of superoxide dismutase (SOD) in the PQ group was decreased in the peripheral blood. As com-pared with the PQ group, the level of ROS and the content of MDA in the PQ+OPC group were significantly re-duced, the activity SOD in the PQ+OPC group was increased in the peripheral blood; the level of ROS and the content of MDA were also reduced in lung tissues in the PQ+OPC group. Moreover, compared with the con-trol group, the phosphorylation of IκBα and the expression of NF-κB p65 were increased in lung tissues in the PQ group. The phosphorylation of IκBα and the expression of NF-κB p65 were decreased in lung tissues in the PQ+OPC group as compared with the PQ group. In addition, compared with the control group, the expressions of HO-1 and Nrf2 were increased in lung tissues in OPC group, and these were decreased in lung tissues in PQ groups. Furthermore, the expressions of HO-1 and Nrf2 were also increased in lung tissues in PQ+OPC as com-pared with the PQ group. Conclusion: OPC could alleviate PQ-induced systemic toxicity in mice by regulating oxidative stress via NF-κB and Nrf2 pathway.

Syndecan-2 Is a Novel Target of Insulin-Like Growth Factor Binding Protein-3 and Is Over-Expressed in Fibrosis

PubMed Central

Ruiz, Ximena D.; Mlakar, Logan R.; Yamaguchi, Yukie; Su, Yunyun; Larregina, Adriana T.; Pilewski, Joseph M.; Feghali-Bostwick, Carol A.

2012-01-01

Extracellular matrix deposition and tissue scarring characterize the process of fibrosis. Transforming growth factor beta (TGFβ) and Insulin-like growth factor binding protein-3 (IGFBP-3) have been implicated in the pathogenesis of fibrosis in various tissues by inducing mesenchymal cell proliferation and extracellular matrix deposition. We identified Syndecan-2 (SDC2) as a gene induced by TGFβ in an IGFBP-3-dependent manner. TGFβ induction of SDC2 mRNA and protein required IGFBP-3. IGFBP-3 independently induced production of SDC2 in primary fibroblasts. Using an ex-vivo model of human skin in organ culture expressing IGFBP-3, we demonstrate that IGFBP-3 induces SDC2 ex vivo in human tissue. We also identified Mitogen-activated protein kinase-interacting kinase (Mknk2) as a gene induced by IGFBP-3. IGFBP-3 triggered Mknk2 phosphorylation resulting in its activation. Mknk2 independently induced SDC2 in human skin. Since IGFBP-3 is over-expressed in fibrotic tissues, we examined SDC2 levels in skin and lung tissues of patients with systemic sclerosis (SSc) and lung tissues of patients with idiopathic pulmonary fibrosis (IPF). SDC2 levels were increased in fibrotic dermal and lung tissues of patients with SSc and in lung tissues of patients with IPF. This is the first report describing elevated levels of SDC2 in fibrosis. Increased SDC2 expression is due, at least in part, to the activity of two pro-fibrotic factors, TGFβ and IGFBP-3. PMID:22900087

Syndecan-2 is a novel target of insulin-like growth factor binding protein-3 and is over-expressed in fibrosis.

PubMed

Ruiz, Ximena D; Mlakar, Logan R; Yamaguchi, Yukie; Su, Yunyun; Larregina, Adriana T; Pilewski, Joseph M; Feghali-Bostwick, Carol A

2012-01-01

Extracellular matrix deposition and tissue scarring characterize the process of fibrosis. Transforming growth factor beta (TGFβ) and Insulin-like growth factor binding protein-3 (IGFBP-3) have been implicated in the pathogenesis of fibrosis in various tissues by inducing mesenchymal cell proliferation and extracellular matrix deposition. We identified Syndecan-2 (SDC2) as a gene induced by TGFβ in an IGFBP-3-dependent manner. TGFβ induction of SDC2 mRNA and protein required IGFBP-3. IGFBP-3 independently induced production of SDC2 in primary fibroblasts. Using an ex-vivo model of human skin in organ culture expressing IGFBP-3, we demonstrate that IGFBP-3 induces SDC2 ex vivo in human tissue. We also identified Mitogen-activated protein kinase-interacting kinase (Mknk2) as a gene induced by IGFBP-3. IGFBP-3 triggered Mknk2 phosphorylation resulting in its activation. Mknk2 independently induced SDC2 in human skin. Since IGFBP-3 is over-expressed in fibrotic tissues, we examined SDC2 levels in skin and lung tissues of patients with systemic sclerosis (SSc) and lung tissues of patients with idiopathic pulmonary fibrosis (IPF). SDC2 levels were increased in fibrotic dermal and lung tissues of patients with SSc and in lung tissues of patients with IPF. This is the first report describing elevated levels of SDC2 in fibrosis. Increased SDC2 expression is due, at least in part, to the activity of two pro-fibrotic factors, TGFβ and IGFBP-3.

Salicin from Willow Bark can Modulate Neurite Outgrowth in Human Neuroblastoma SH-SY5Y Cells.

PubMed

Wölfle, Ute; Haarhaus, Birgit; Kersten, Astrid; Fiebich, Bernd; Hug, Martin J; Schempp, Christoph M

2015-10-01

Salicin from willow bark has been used throughout centuries in China and Europe for the treatment of pain, headache, and inflammatory conditions. Recently, it could be demonstrated that salicin binds and activates the bitter taste receptor TAS2R16. Studies on rodent tissues showed the general expression of bitter taste receptors (TAS2Rs) in rodent brain. Here, we demonstrate the expression of hTAS2R16 in human neuronal tissues and the neuroblastoma cell line SH-SY5Y. The functionality was analyzed in the neuroblastoma cell line SH-SY5Y after stimulation with salicin, a known TAS2R16 agonist. In this setting salicin induced in SH-SY5Y cells phosphorylation of ERK and CREB, the key transcription factor of neuronal differentiation. PD98059, an inhibitor of the ERK pathway, as well as probenecid, a TAS2R16 antagonist, inhibited receptor phosphorylation as well as neurite outgrowth. These data show that salicin might modulate neurite outgrowth by bitter taste receptor activation. Copyright © 2015 John Wiley & Sons, Ltd.

The SIRT1 inhibitor EX-527 suppresses mTOR activation and alleviates acute lung injury in mice with endotoxiemia.

PubMed

Huang, Jing; Tian, Rui; Yang, Yongqiang; Jiang, Rong; Dai, Jie; Tang, Li; Zhang, Li

2017-11-01

It is generally regarded that Sirtuin 1 (SIRT1), a longevity factor in mammals, acts as a negative regulator of inflammation. However, recent studies also found that SIRT1 might be a detrimental factor under certain inflammatory circumstance. In this study, the potential pathophysiological roles and the underlying mechanisms of SIRT1 in a mouse model with endotoxemia-associated acute lung injury were investigated. The results indicated that treatment with the selective SIRT1 inhibitor EX-527 suppressed LPS-induced elevation of TNF-α and IL-6 in plasma. Treatment with EX-527 attenuated LPS-induced histological abnormalities in lung tissue, which was accompanied with decreased myeloperoxidase level and suppressed induction of tissue factor and plasminogen activator inhibitor-1. Treatment with EX-527 also suppressed LPS-induced phosphorylation of eukaryotic translation initiation factor-binding protein 1 (4E-BP1). Co-administration of a mammalian target of rapamycin (mTOR) activator 3-benzyl-5-[(2-nitrophenoxy) methyl]-dihydrofuran-2 (3H)-one (3BDO) abolished the inhibitory effects of EX-527 on 4E-BP1 phosphorylation. Meanwhile, the inhibitory effects of EX-527 on IL-6 induction and the beneficial effects of EX-527 on lung injury were partially reversed by 3BDO. This study suggests that selective inhibition of SIRT1 by EX-527 might alleviate endotoxemia-associated acute lung injury partially via suppression of mTOR, which implies that SIRT1 selective inhibitors might have potential value for the pharmacological intervention of inflammatory lung injury.

Prostaglandin E2 mediates phosphorylation and down-regulation of the tuberous sclerosis-2 tumor suppressor (tuberin) in human endometrial adenocarcinoma cells via the Akt signaling pathway.

PubMed

Sales, Kurt J; Battersby, Sharon; Williams, Alistair R W; Anderson, Richard A; Jabbour, Henry N

2004-12-01

Prostaglandin (PG) E2 promotes tumor growth via interaction with its G protein-coupled receptors and activation of intracellular signaling. Tuberous sclerosis 2 (tuberin) is a tumor suppressor, which negatively regulates cell growth. Its phosphorylation results in its inactivation and targeted down- regulation, thus lifting the growth inhibition effects. This study investigated the expression and localization of tuberin in neoplastic and normal endometrium and the effect of PGE2 on phosphorylation of tuberin via the Akt pathway. Quantitative RT-PCR and Western blot analysis demonstrated reduced expression of tuberin in neoplastic tissue, compared with normal endometrial tissue. Tuberin expression was localized by immunohistochemistry to the glandular epithelial compartment in neoplastic and normal endometrium. We investigated the effect of PGE2 on phosphorylation of tuberin via the Akt pathway. Treatment of neoplastic and normal endometrium with 100 nm PGE2 enhanced phosphorylated tuberin immunoreactivity in the glandular epithelium. PGE2 also phosphorylated Akt and tuberin in Ishikawa endometrial adenocarcinoma cells, leading to a reduction in expression of total tuberin protein. Cotreatment of cells with wortmannin or LY294002 inhibited the PGE2-induced phosphorylation of Akt and tuberin. These data suggest that PGE2 signaling may promote endometrial tumorigenesis by inactivation of tuberin after its phosphorylation via the Akt signaling pathway.

Crop milk protein is synthesised following activation of the IRS1/Akt/TOR signalling pathway in the domestic pigeon (Columba livia).

PubMed

Hu, X-C; Gao, C-Q; Wang, X-H; Yan, H-C; Chen, Z-S; Wang, X-Q

2016-12-01

The experiment was conducted to study whether insulin receptor substance 1 (IRS1) / Protein kinase B (Akt)/target of the rapamycin (TOR) signalling pathway activation stimulates crop milk protein synthesis in the domestic pigeon (Columba livia). Crop milk was collected from ten 1-d-old squabs and analysed for nutrient content. During the non-breeding period and the first day of lactation, blood samples were collected from 5 pairs of breeding pigeons and the levels of prolactin and insulin were determined. Crop samples were collected from 5 pairs of breeders at d 14 and 16 of the incubation period and d 1, 3 and 7 of the lactation period. Crop samples were evaluated for changes in crop weight and thickness and changes in the expression patterns of IRS1/Akt/TOR signalling pathway-related proteins. The results demonstrated that prolactin induces a gradual increase in the relative weight and thickness of the crop, with crops reaching a maximum size at the third day of lactation. Pigeon crop milk contains 64.1% crude protein and 29.7% crude fat based on dry weight. Serum prolactin and insulin levels in the lactation period were significantly higher than those in the non-breeding period. Compared with non-breeding pigeons, the expression of the phosphorylated IRS1 phosphorylated Akt, phosphorylated TOR, phosphorylated ribosomal protein S6 kinase, phosphorylated S6, phosphorylated eukaryotic initiation factor 4E binding protein 1 and eukaryotic initiation factor 4E were significantly up-regulated in the crop of pigeons in the lactation period. In conclusion, prolactin might induce changes in crop tissue and form the physiological structure for crop milk synthesis. Furthermore, the synthesis of crop milk protein is regulated by activation of the IRS1/Akt/TOR signalling pathway.

Influence of Gestational Overfeeding on Cardiac Morphometry and Hypertrophic Protein Markers in Fetal Sheep

PubMed Central

Fan, Xiujuan; Turdi, Subat; Ford, Stephen P.; Hua, Yinan; Nijland, Mark J.; Zhu, Meijun; Nathanielsz, Peter W.; Ren, Jun

2010-01-01

Intrauterine overnutrition is associated with development of cardiovascular disease in adulthood although the underlying mechanism has not been precisely elucidated. This study evaluated the effects of maternal overnutrition on fetal cardiac morphometry and hypertrophy-related mRNA/protein expression. Multiparous ewes were fed either 150% of NRC nutrient requirements (overfed group) or 100% of NRC requirements (control group) from 60 days before mating to day 75 (D75) of gestation, when ewes were euthanized. Cardiac morphometry, histology and expression of Akt, forkhead-3a (Foxo3a), glycogen synthase kinase-3β (GSK3β), mammalian target of rapamycin (mTOR), NFATc3 and GATA4, atrial natriuretic factor (ANF), calcineurin A and caspase-8 were examined. Crown rump length, left and right ventricular free wall weights and left ventricular wall thickness were increased in D75 overnourished fetuses. H&E staining revealed irregular myofiber orientation and increased interstitial space in heart tissues from overfed group. Masson’s trichrome staining displayed myofiber hypertrophy and fascicular disarray in heart tissues from overfed group. Overfeeding significantly enhanced Foxo3a phosphorylation in both ventricles while protein expression of Akt, Foxo3a, GSK3β and caspase-8 as well as phosphorylated Akt and GSK3β in either ventricle was unaffected. Overfeeding increased left ventricular mTOR, NFATc3 (both total and phosphorylated) and calcineurin A. GATA4, pGATA4 and ANF expression were unchanged in both ventricles. Collectively, our data suggested that overfeeding during early to mid gestation (D75) leads to morphometric changes without overt pathology which may be related to elevated expression of mTOR, NFATc3, calcineurin A and phosphorylation of Foxo3a, mTOR and NFATc3. PMID:20188535

Molecular mechanisms of ulcer healing.

PubMed

Tarnawski, A

2000-04-01

An ulcer in the gastrointestinal tract is a deep necrotic lesion penetrating the entire mucosal thickness and muscularis mucosae. Ulcer healing is an active process of filling the mucosal defect with proliferating and migrating epithelial and connective tissue cells. At the ulcer margin, epithelial cells proliferate and migrate onto the granulation tissue to cover (reepithelialize) the ulcer and also invade granulation tissue to reconstruct glandular structures within the ulcer scar. The reepithelialization and reconstruction of glandular structures is controlled by growth factors: trefoil peptides, EGF, HGF, bFGF and PDGF; and locally produced cytokines by regenerating cells in an orderly fashion and integrated manner to ensure the quality of mucosal restoration. These growth factors, most notably EGF, trigger cell proliferation via signal transduction pathways involving EGF-R, adapter proteins (Grb2, Shc and Sos), Ras, Raf1 and MAP (Erk1/Erk2) kinases, which, after translocation to nuclei, activate transcription factors and cell proliferation. Cell migration requires cytoskeletal rearrangements and is controlled by growth factors via Rho/Rac and signaling pathways involving PLC-gamma, PI-3 K and phosphorylation of focal adhesion proteins. Granulation tissue develops at the ulcer base. It consists of connective tissue cells: fibroblasts, macrophages and proliferating endothelial cells forming microvessels under the control of angiogenic growth factors: bFGF, VEGF and angiopoietins, which all promote angiogenesiscapillary vessel formation, essential for the restoration of microvascular network in the mucosa and thus crucial for oxygen and nutrient supply. The major mechanism of activation of angiogenic growth factors and their receptor expression appears to be hypoxia, which activates hypoxia-inducible factor, which binds to VEGF promoter.

A new mouse model of metabolic syndrome and associated complications

PubMed Central

Wang, Yun; Zheng, Yue; Nishina, Patsy M; Naggert, Jürgen K.

2010-01-01

Metabolic Syndrome (MS) encompasses a clustering of risk factors for cardiovascular disease, including obesity, insulin resistance, and dyslipidemia. We characterized a new mouse model carrying a dominant mutation, C57BL/6J-Nmf15/+ (B6-Nmf15/+), which develops additional complications of MS such as adipose tissue inflammation and cardiomyopathy. A backcross was used to genetically map the Nmf15 locus. Mice were examined in the CLAMS™ animal monitoring system, and dual energy X-ray absorptiometry and blood chemistry analyses were performed. Hypothalamic LepR, SOCS1 and STAT3 phosphorylation were examined. Cardiac function was assessed by Echo- and Electro Cardiography. Adipose tissue inflammation was characterized by in situ hybridization and measurement of Jun kinase activity. The Nmf15 locus mapped to distal mouse chromosome 5 with a LOD score of 13.8. Nmf15 mice developed obesity by 12 weeks of age. Plasma leptin levels were significantly elevated in pre-obese Nmf15 mice at 8 weeks of age and an attenuated STAT3 phosphorylation in the hypothalamus suggests a primary leptin resistance. Adipose tissue from Nmf15 mice showed a remarkable degree of inflammation and macrophage infiltration as indicated by expression of the F4/80 marker and increased phosphorylation of JNK1/2. Lipidosis was observed in tubular epithelial cells and glomeruli of the kidney. Nmf15 mice demonstrate both histological and pathophysiological evidence of cardiomyopathy. The Nmf15 mouse model provides a new entry point into pathways mediating leptin resistance and obesity. It is one of few models that combine many aspects of metabolic syndrome and can be useful for testing new therapeutic approaches for combating obesity complications, particularly cardiomyopathy. PMID:19398498

Mitochondrial NAD(P)H In vivo: Identifying Natural Indicators of Oxidative Phosphorylation in the (31)P Magnetic Resonance Spectrum.

PubMed

Conley, Kevin E; Ali, Amir S; Flores, Brandon; Jubrias, Sharon A; Shankland, Eric G

2016-01-01

Natural indicators provide intrinsic probes of metabolism, biogenesis and oxidative protection. Nicotinamide adenine dinucleotide metabolites (NAD(P)) are one class of indicators that have roles as co-factors in oxidative phosphorylation, glycolysis, and anti-oxidant protection, as well as signaling in the mitochondrial biogenesis pathway. These many roles are made possible by the distinct redox states (NAD(P)(+) and NAD(P)H), which are compartmentalized between cytosol and mitochondria. Here we provide evidence for detection of NAD(P)(+) and NAD(P)H in separate mitochondrial and cytosol pools in vivo in human tissue by phosphorus magnetic resonance spectroscopy ((31)P MRS). These NAD(P) pools are identified by chemical standards (NAD(+), NADP(+), and NADH) and by physiological tests. A unique resonance reflecting mitochondrial NAD(P)H is revealed by the changes elicited by elevation of mitochondrial oxidation. The decline of NAD(P)H with oxidation is matched by a stoichiometric rise in the NAD(P)(+) peak. This unique resonance also provides a measure of the improvement in mitochondrial oxidation that parallels the greater phosphorylation found after exercise training in these elderly subjects. The implication is that the dynamics of the mitochondrial NAD(P)H peak provides an intrinsic probe of the reversal of mitochondrial dysfunction in elderly muscle. Thus, non-invasive detection of NAD(P)(+) and NAD(P)H in cytosol vs. mitochondria yields natural indicators of redox compartmentalization and sensitive intrinsic probes of the improvement of mitochondrial function with an intervention in human tissues in vivo. These natural indicators hold the promise of providing mechanistic insight into metabolism and mitochondrial function in vivo in a range of tissues in health, disease and with treatment.

Effect of metabolic alterations on the accumulation of technetium-99m-labeled d, l-HMPAO in slices of rat cerebral cortex

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ahn, C.S.; Tow, D.E.; Yu, C.C.

1994-03-01

It is widely recognized that the distribution of technetium-99m-labeled d,l-hexamethylpropylene amine oxime ({sup 99m}Tc-HMPAO) in the brain is determined by the regional blood flow. However, other factors may affect this process including the metabolism of the brain tissue. To examine this possibility we studied the effects of metabolic alterations on {sup 99m}Tc-HMPAO uptake in rat brain cortex slices, with concurrent measurement of oxygen consumption (QO{sub 2}). {sup 99m}Tc-HMPAO uptake was determined by incubating slices of rat cerebral cortex at 37{degrees}C in Krebs-Ringer phosphate glucose medium containing {sup 99m}Tc-HMPAO with and without test substances. Differential gradients for {sup 99m}Tc activity betweenmore » the tissue and the suspending medium (T/M ratio) were derived from the equation T/M[{sup 99m}Tc] = counts per gram of tissue/counts per milliliter of medium. The QO{sub 2} of the brain slices was measured using a biological oxygen monitor equipped with a polarographic oxygen probe. Inhibitors affecting oxidative phosphorylation caused parallel suppression of the T/M ratio and QO{sub 2}. Agents that uncouple oxidation from phosphorylation increased the QO{sub 2} and decreased the T/M ratio. Incubation of slices at 22{degrees}C depressed the T/M ratio and QO{sub 2}. The presence of inhibitors of oxidative phosphorylation in the incubation medium increased the release of {sup 99m}Tc activity from slices that had been prelabeled with {sup 99m}Tc-HMPAO. These findings suggest that the altered metabolic status of the brain tissue modulates the kinetics and net accumulation of {sup 99m}Tc-HMPAO at the cellular level by either depressing uptake, increasing back-diffusion, or both. 33 refs., 4 figs., 3 tabs.« less

MiR-214 regulates oral cancer KB cell apoptosis through targeting RASSF5.

PubMed

Li, T K; Yin, K; Chen, Z; Bao, Y; Zhang, S X

2017-03-08

Ras association domain family member 5 (RASSF5), a member of the Ras association domain family, induces cell apoptosis by phosphorylating FOXO3a, which triggers target gene BIM (pro-apoptotic factor) activation. MiR-214 is overexpressed in oral cancer tissue, indicating its possible involvement in oral cancer pathogenesis. Bioinformatics analysis has revealed a complimentary sequence between miR-214 and the 3'-UTR of RASSF5 mRNA. However, whether miR-124 regulates RASSF5 in oral cancer remains poorly understood. We aimed to investigate the role of miR-214 in RASSF5 expression regulation in oral cancer. Tumor and paracarcinoma tissues were obtained from 48 oral cancer patients to examine miR-214 and RASSF5 expression. The relationship between miR-214 and RASSF5 was investigated by dual luciferase reporter gene assay. Oral cancer KB cells were cultured in vitro and divided into inhibitor NC, miR-214 inhibitor, Scramble-pMD18, RASSF5-pMD18, and miR-214 inhibitor + RASSF5-pMD18 groups. Caspase 3 activity, cell apoptosis, and total protein expression were measured by spectrophotometry, flow cytometry, and western blot, respectively. MiR-214 expression was significantly increased, while that of RASSF5 decreased in oral cancer tumor tissues compared to paracarcinoma tissues. Luciferase assay showed that miR-214 suppressed RASSF5 expression by targeting its 3'-UTR. Down-regulation of miR-214 and/or enhancement of RASSF5 expression markedly increased FOXO3a phosphorylation, BIM expression, caspase 3 activity, and apoptosis. In conclusion, miR-214 expression was elevated and RASSF5 was down-regulated in oral cancer. Moreover, miR-214 regulated KB cell apoptosis through targeted inhibition of RASSF5 expression, FOXO3a phosphorylation, and BIM expression, suggesting its possible application as a novel therapeutic oral cancer target.

β-Amyloid Oligomers Induce Phosphorylation of Tau and Inactivation of Insulin Receptor Substrate via c-Jun N-Terminal Kinase Signaling: Suppression by Omega-3 Fatty Acids and Curcumin

PubMed Central

Ma, Qiu-Lan; Yang, Fusheng; Rosario, Emily R.; Ubeda, Oliver J.; Beech, Walter; Gant, Dana J.; Chen, Ping Ping; Hudspeth, Beverly; Chen, Cory; Zhao, Yongle; Vinters, Harry V.; Frautschy, Sally A.

2009-01-01

Both insulin resistance (type II diabetes) and β-amyloid (Aβ) oligomers are implicated in Alzheimer's disease (AD). Here, we investigate the role of Aβ oligomer-induced c-Jun N-terminal kinase (JNK) activation leading to phosphorylation and degradation of the adaptor protein insulin receptor substrate-1 (IRS-1). IRS-1 couples insulin and other trophic factor receptors to downstream kinases and neuroprotective signaling. Increased phospho-IRS-1 is found in AD brain and insulin-resistant tissues from diabetics. Here, we report Aβ oligomers significantly increased active JNK and phosphorylation of IRS-1 (Ser616) and tau (Ser422) in cultured hippocampal neurons, whereas JNK inhibition blocked these responses. The omega-3 fatty acid docosahexaenoic acid (DHA) similarly inhibited JNK and the phosphorylation of IRS-1 and tau in cultured hippocampal neurons. Feeding 3xTg-AD transgenic mice a diet high in saturated and omega-6 fat increased active JNK and phosphorylated IRS-1 and tau. Treatment of the 3xTg-AD mice on high-fat diet with fish oil or curcumin or a combination of both for 4 months reduced phosphorylated JNK, IRS-1, and tau and prevented the degradation of total IRS-1. This was accompanied by improvement in Y-maze performance. Mice fed with fish oil and curcumin for 1 month had more significant effects on Y-maze, and the combination showed more significant inhibition of JNK, IRS-1, and tau phosphorylation. These data indicate JNK mediates Aβ oligomer inactivation of IRS-1 and phospho-tau pathology and that dietary treatment with fish oil/DHA, curcumin, or a combination of both has the potential to improve insulin/trophic signaling and cognitive deficits in AD. PMID:19605645

Inhibition of EGFR/MAPK signaling reduces microglial inflammatory response and the associated secondary damage in rats after spinal cord injury.

PubMed

Qu, Wen-Sheng; Tian, Dai-Shi; Guo, Zhi-Bao; Fang, Jun; Zhang, Qiang; Yu, Zhi-Yuan; Xie, Min-Jie; Zhang, Hua-Qiu; Lü, Jia-Gao; Wang, Wei

2012-07-23

Emerging evidence indicates that reactive microglia-initiated inflammatory responses are responsible for secondary damage after primary traumatic spinal cord injury (SCI); epidermal growth factor receptor (EGFR) signaling may be involved in cell activation. In this report, we investigate the influence of EGFR signaling inhibition on microglia activation, proinflammatory cytokine production, and the neuronal microenvironment after SCI. Lipopolysaccharide-treated primary microglia/BV2 line cells and SCI rats were used as model systems. Both C225 and AG1478 were used to inhibit EGFR signaling activation. Cell activation and EGFR phosphorylation were observed after fluorescent staining and western blot. Production of interleukin-1 beta (IL-1 β) and tumor necrosis factor alpha (TNF α) was tested by reverse transcription PCR and ELISA. Western blot was performed to semi-quantify the expression of EGFR/phospho-EGFR, and phosphorylation of Erk, JNK and p38 mitogen-activated protein kinases (MAPK). Wet-dry weight was compared to show tissue edema. Finally, axonal tracing and functional scoring were performed to show recovery of rats. EGFR phosphorylation was found to parallel microglia activation, while EGFR blockade inhibited activation-associated cell morphological changes and production of IL-1 β and TNF α. EGFR blockade significantly downregulated the elevated MAPK activation after cell activation; selective MAPK inhibitors depressed production of cytokines to a certain degree, suggesting that MAPK mediates the depression of microglia activation brought about by EGFR inhibitors. Subsequently, seven-day continual infusion of C225 or AG1478 in rats: reduced the expression of phospho-EGFR, phosphorylation of Erk and p38 MAPK, and production of IL-1 β and TNF α; lessened neuroinflammation-associated secondary damage, like microglia/astrocyte activation, tissue edema and glial scar/cavity formation; and enhanced axonal outgrowth and functional recovery. These findings indicate that inhibition of EGFR/MAPK suppresses microglia activation and associated cytokine production; reduces neuroinflammation-associated secondary damage, thus provides neuroprotection to SCI rats, suggesting that EGFR may be a therapeutic target, and C225 and AG1478 have potential for use in SCI treatment.

Streptococcus pyogenes CAMP factor promotes bacterial adhesion and invasion in pharyngeal epithelial cells without serum via PI3K/Akt signaling pathway.

PubMed

Kurosawa, Mie; Oda, Masataka; Domon, Hisanori; Isono, Toshihito; Nakamura, Yuki; Saitoh, Issei; Hayasaki, Haruaki; Yamaguchi, Masaya; Kawabata, Shigetada; Terao, Yutaka

2018-01-01

Streptococcus pyogenes is a bacterium that causes systemic diseases, such as pharyngitis and toxic shock syndrome, via oral- or nasal-cavity infection. S. pyogenes produces various molecules known to function with serum components that lead to bacterial adhesion and invasion in human tissues. In this study, we identified a novel S. pyogenes adhesin/invasin. Our results revealed that CAMP factor promoted streptococcal adhesion and invasion in pharyngeal epithelial Detroit562 cells without serum. Recombinant CAMP factor initially localized on the membranes of cells and then became internalized in the cytosol following S. pyogenes infection. Additionally, CAMP factor phosphorylated phosphoinositide 3-kinase and serine-threonine kinase in the cells. ELISA results demonstrate that CAMP factor affected the amount of phosphorylated phosphoinositide 3-kinase and serine-threonine kinase in Detroit562 cells. Furthermore, CAMP factor did not reverse the effect of phosphoinositide 3-kinase knockdown by small interfering RNA in reducing the level of adhesion and invasion of S. pyogenes isogenic cfa-deficient mutant. These results suggested that S. pyogenes CAMP factor activated the phosphoinositide 3-kinase/serine-threonine kinase signaling pathway, promoting S. pyogenes invasion of Detroit562 cells without serum. Our findings suggested that CAMP factor played an important role on adhesion and invasion in pharyngeal epithelial cells. Copyright © 2017 Institut Pasteur. Published by Elsevier Masson SAS. All rights reserved.

Expression and localization of epithelial stem cell and differentiation markers in equine skin, eye and hoof.

PubMed

Linardi, Renata L; Megee, Susan O; Mainardi, Sarah R; Senoo, Makoto; Galantino-Homer, Hannah L

2015-08-01

The limited characterization of equine skin, eye and hoof epithelial stem cell (ESC) and differentiation markers impedes the investigation of the physiology and pathophysiology of these tissues. To characterize ESC and differentiation marker expression in epithelial tissues of the equine eye, haired skin and hoof capsule. Indirect immunofluorescence microscopy and immunoblotting were used to detect expression and tissue localization of keratin (K) isoforms K3, K10, K14 and K124, the transcription factor p63 (a marker of ESCs) and phosphorylated p63 [pp63; a marker of ESC transition to transit-amplifying (TA) cell] in epithelial tissues of the foot (haired skin, hoof coronet and hoof lamellae) and the eye (limbus and cornea). Expression of K14 was restricted to the basal layer of epidermal lamellae and to basal and adjacent suprabasal layers of the haired skin, coronet and corneal limbus. Coronary and lamellar epidermis was negative for both K3 and K10, which were expressed in the cornea/limbus epithelium and haired skin epidermis, respectively. Variable expression of p63 with relatively low to high levels of phosphorylation was detected in individual basal and suprabasal cells of all epithelial tissues examined. To the best of the author's knowledge, this is the first report of the characterization of tissue-specific keratin marker expression and the localization of putative epithelial progenitor cell populations, including ESCs (high p63 expression with low pp63 levels) and TA cells (high expression of both p63 and pp63), in the horse. These results will aid further investigation of epidermal and corneal epithelial biology and regenerative therapies in horses. © 2015 ESVD and ACVD.

The utility of vitamin K3 (menadione) against pancreatic cancer.

PubMed

Osada, Shinji; Tomita, Hiroyuki; Tanaka, Yoshihiro; Tokuyama, Yasuharu; Tanaka, Hidenori; Sakashita, Fumio; Takahashi, Takao

2008-01-01

To evaluate the efficacy of vitamin K3 (VK3) against pancreatic cancer, the molecular mechanism of VK3 or gemcitabine (GEM)-induced inhibition of proliferation was characterized. The cell viability was determined using the 3-[4,5-dimethylthiazol]-2,5-diphenyl tetrazolium bromide (MTT) test method. The expressions of cellular proteins were evaluated by Western blot analysis. For morphological studies of the in vivo transplanted cancer cells, the tissues were stained with hematoxylin and eosin. The IC50 of VK3 for pancreatic cancer cells was calculated for 42.1 +/- 3.5 microM. Western blot analysis showed that VK3 induced rapid phosphorylation of extracellular signal-regulated kinase (ERK) and c-Jun NH2-terminal kinase (JNK) 30 minutes after application. ERK but not JNK phosphorylation was maintained for at least 12 hours. Activation of apoptosis by VK3, as shown by molecular weight shifts of the pro-activated 32-kDa form of caspase-3 and poly(ADP-ribose)polymerase (PARP) cleavage of the 112-kDa form, was found. Treatment with the thiol antioxidant, L-cysteine (>0.2 mM), completely abrogated the VK3-induced phosphorylation of ERK, but not the JNK, and inhibition of proliferation. A caspase-3 inhibitor antagonized caspase-3 activation, but had no inhibitory effect on the proliferative activity of VK3. GEM at concentrations >0.1 microg/ml was found to inhibit cell proliferation after 24 hours. GEM also induced phosphorylation of JNK, activation of caspase-3 and accumulation of cyclin B1. Local application of VK3 was found to induce extensive tumor tissue necrosis, but slight hematemesis without necrosis was observed 48 hours after GEM injection. In Western blot, ERK but not JNK phosphorylation, was clearly detected in response to VK3 injection into the tumor tissue. The action of VK3 may lead to a favorable outcome against pancreatic cancer, and the detection of ERK phosphorylation in the tissue is important for predicting this effect.

Periparturient dairy cows do not exhibit hepatic insulin resistance, yet adipose-specific insulin resistance occurs in cows prone to high weight loss.

PubMed

Zachut, M; Honig, H; Striem, S; Zick, Y; Boura-Halfon, S; Moallem, U

2013-09-01

The periparturient period in dairy cows is associated with alterations in insulin action in peripheral tissues; however, the molecular mechanism underlying this process is not completely understood. The objective was to examine the response to a glucose tolerance test (GTT) and to analyze insulin signaling in liver and adipose tissues in pre- and postpartum dairy cows. Liver and adipose tissue biopsies were taken before and after GTT, at 17d prepartum and again at 3 to 5d postpartum from 8 high-yielding Israeli Holstein dairy cows. Glucose clearance rate after GTT was similar pre- and postpartum. Basal insulin concentrations and the insulin response to GTT were approximately 4-fold higher prepartum than postpartum. In accordance, phosphorylation of the hepatic insulin receptor after GTT was higher prepartum than postpartum. Across periods, a positive correlation was observed between the basal and peak plasma insulin and phosphorylated insulin receptor after GTT in the liver. Hepatic phosphorylation of protein kinase B after GTT was elevated pre- and postpartum. Conversely, in adipose tissue, phosphorylation of protein kinase B after GTT pre- and postpartum was increased only in 4 out of 8 cows that lost less body weight postpartum. Our results demonstrate that hepatic insulin signaling is regulated by plasma insulin concentrations as part of the homeorhetic adjustments toward calving, and do not support a model of hepatic insulin resistance in periparturient cows. Nevertheless, we suggest that specific insulin resistance in adipose tissue occurs pre- and postpartum only in cows prone to high weight loss. The different responses among these cows imply that genetic background may affect insulin responsiveness in adipose tissue pre- and postpartum. Copyright © 2013 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Fructose-enriched diet induces inflammation and reduces antioxidative defense in visceral adipose tissue of young female rats.

PubMed

Kovačević, Sanja; Nestorov, Jelena; Matić, Gordana; Elaković, Ivana

2017-02-01

The consumption of refined, fructose-enriched food continuously increases and has been linked to development of obesity, especially in young population. Low-grade inflammation and increased oxidative stress have been implicated in the pathogenesis of obesity-related disorders including type 2 diabetes. In this study, we examined alterations in inflammation and antioxidative defense system in the visceral adipose tissue (VAT) of fructose-fed young female rats, and related them to changes in adiposity and insulin sensitivity. We examined the effects of 9-week fructose-enriched diet applied immediately after weaning on nuclear factor κB (NF-κB) intracellular distribution, and on the expression of pro-inflammatory cytokines (IL-1β and TNFα) and key antioxidative enzymes in the VAT of female rats. Insulin signaling in the VAT was evaluated at the level of insulin receptor substrate-1 (IRS-1) protein and its inhibitory phosphorylation on Ser 307 . Fructose-fed rats had increased VAT mass along with increased NF-κB nuclear accumulation and elevated IL-1β, but not TNFα expression. The protein levels of antioxidative defense enzymes, mitochondrial manganese superoxide dismutase 2, and glutathione peroxidase, were reduced, while the protein content of IRS-1 and its inhibitory phosphorylation were not altered by fructose diet. The results suggest that fructose overconsumption-related alterations in pro-inflammatory markers and antioxidative capacity in the VAT of young female rats can be implicated in the development of adiposity, but do not affect inhibitory phosphorylation of IRS-1.

Rhythmic expression of DEC2 protein in vitro and in vivo.

PubMed

Sato, Fuyuki; Muragaki, Yasuteru; Kawamoto, Takeshi; Fujimoto, Katsumi; Kato, Yukio; Zhang, Yanping

2016-06-01

Basic helix-loop-helix (bHLH) transcription factor DEC2 (bHLHE41/Sharp1) is one of the clock genes that show a circadian rhythm in various tissues. DEC2 regulates differentiation, sleep length, tumor cell invasion and apoptosis. Although studies have been conducted on the rhythmic expression of DEC2 mRNA in various tissues, the precise molecular mechanism of DEC2 expression is poorly understood. In the present study, we examined whether DEC2 protein had a rhythmic expression. Western blot analysis for DEC2 protein revealed a rhythmic expression in mouse liver, lung and muscle and in MCF-7 and U2OS cells. In addition, AMP-activated protein kinase (AMPK) activity (phosphorylation of AMPK) in mouse embryonic fibroblasts (MEFs) exhibited a rhythmic expression under the condition of medium change or glucose-depleted medium. However, the rhythmic expression of DEC2 in MEF gradually decreased in time under these conditions. The medium change affected the levels of DEC2 protein and phosphorylation of AMPK. In addition, the levels of DEC2 protein showed a rhythmic expression in vivo and in MCF-7 and U2OS cells. The results showed that the phosphorylation of AMPK immunoreactivity was strongly detected in the liver and lung of DEC2 knockout mice compared with that of wild-type mice. These results may provide new insights into rhythmic expression and the regulation between DEC2 protein and AMPK activity.

Pim-2 activates API-5 to inhibit the apoptosis of hepatocellular carcinoma cells through NF-kappaB pathway.

PubMed

Ren, Ke; Zhang, Wei; Shi, Yujun; Gong, Jianping

2010-06-01

Pim-2 is proved to be relevant to the tumorigenesis of hepatocellular carcinoma (HCC), but the mechanism is unclear. We studied the relationship among Pim-2, NF-kappaB and API-5. In our experiment, expression level of the three factors and phosphorylation level of API-5, as well as NF-kappaB activity, were detected in HCC tissues and the nontumorous controls. Then Pim-2 gene was transfected into nontumorous liver cells L02, and Pim-2 SiRNA was transfected into hepatoblastoma cell line HepG2. Parthenolide was added as NF-kappaB inhibitor. The same detections as above were repeated in the cells, along with the apoptosis analysis. We found the levels of Pim-2, NF-kappaB and API-5, as well as NF-kappaB activity, were significantly higher in HCC tissues. Pim-2 level was increased in L02 cells after the transfection of Pim-2 gene, but decreased in HepG2 cells after the transfection of Pim-2 SiRNA. The levels of NF-kappaB and API-5, as well as NF-kappaB activity and API-5 phosphorylation level, were in accordance with Pim-2 level, but could be reversed by Parthenolide. Cell apoptosis rates were negatively correlated with API-5 phosphorylation level. Therefore, we infer that Pim-2 could activate API-5 to inhibit the apoptosis of liver cells, and NF-kappaB is the key regulator.

[Effects of hyperbaric oxygenation on oxidative phosphorylation in post-nephrotomy tissues sutured with different surgical threads (an experimental study)].

PubMed

Kostenko, V A

1998-01-01

The activity of mitochondrial respiration and oxidative phosphorylation (OP) was studied in white rats subjected to nephrotomy. The suture was made with absorbable surgical threads such as catgut plain, biofil (from dura mater spinalis of the cattle), dexon II (polyglycolic acid). The use of catgut plain inhibits biosynthetic processes 7 and 14 days after operation. Hyperbaric oxygenation enhances oxidative phosphorylation in postoperative renal tissue sutured with different biological and synthetic absorbable surgical threads (catgut, biofil, dexon II) and prevents sharp depression of the above processes in the course of catgut biodegradation. This fact is of great importance for reduction of normal functional and metabolic activity of the operated kidney.

Phosphorylation of a splice variant of collapsin response mediator protein 2 in the nucleus of tumour cells links cyclin dependent kinase-5 to oncogenesis.

PubMed

Grant, Nicola J; Coates, Philip J; Woods, Yvonne L; Bray, Susan E; Morrice, Nicholas A; Hastie, C James; Lamont, Douglas J; Carey, Francis A; Sutherland, Calum

2015-11-10

Cyclin-dependent protein kinase-5 (CDK5) is an unusual member of the CDK family as it is not cell cycle regulated. However many of its substrates have roles in cell growth and oncogenesis, raising the possibility that CDK5 modulation could have therapeutic benefit. In order to establish whether changes in CDK5 activity are associated with oncogenesis one could quantify phosphorylation of CDK5 targets in disease tissue in comparison to appropriate controls. However the identity of physiological and pathophysiological CDK5 substrates remains the subject of debate, making the choice of CDK5 activity biomarkers difficult. Here we use in vitro and in cell phosphorylation assays to identify novel features of CDK5 target sequence determinants that confer enhanced CDK5 selectivity, providing means to select substrate biomarkers of CDK5 activity with more confidence. We then characterize tools for the best CDK5 substrate we identified to monitor its phosphorylation in human tissue and use these to interrogate human tumour arrays. The close proximity of Arg/Lys amino acids and a proline two residues N-terminal to the phosphorylated residue both improve recognition of the substrate by CDK5. In contrast the presence of a proline two residues C-terminal to the target residue dramatically reduces phosphorylation rate. Serine-522 of Collapsin Response Mediator-2 (CRMP2) is a validated CDK5 substrate with many of these structural criteria. We generate and characterise phosphospecific antibodies to Ser522 and show that phosphorylation appears in human tumours (lung, breast, and lymphoma) in stark contrast to surrounding non-neoplastic tissue. In lung cancer the anti-phospho-Ser522 signal is positive in squamous cell carcinoma more frequently than adenocarcinoma. Finally we demonstrate that it is a specific and unusual splice variant of CRMP2 (CRMP2A) that is phosphorylated in tumour cells. For the first time this data associates altered CDK5 substrate phosphorylation with oncogenesis in some but not all tumour types, implicating altered CDK5 activity in aspects of pathogenesis. These data identify a novel oncogenic mechanism where CDK5 activation induces CRMP2A phosphorylation in the nuclei of tumour cells.

An integrative analysis of tissue-specific transcriptomic and metabolomic responses to short-term dietary methionine restriction in mice

PubMed Central

Ghosh, Sujoy; Forney, Laura A.; Wanders, Desiree; Stone, Kirsten P.

2017-01-01

Dietary methionine restriction (MR) produces a coordinated series of transcriptional responses in peripheral tissues that limit fat accretion, remodel lipid metabolism in liver and adipose tissue, and improve overall insulin sensitivity. Hepatic sensing of reduced methionine leads to induction and release of fibroblast growth factor 21 (FGF21), which acts centrally to increase sympathetic tone and activate thermogenesis in adipose tissue. FGF21 also has direct effects in adipose to enhance glucose uptake and oxidation. However, an understanding of how the liver senses and translates reduced dietary methionine into these transcriptional programs remains elusive. A comprehensive systems biology approach integrating transcriptomic and metabolomic readouts in MR-treated mice confirmed that three interconnected mechanisms (fatty acid transport and oxidation, tricarboxylic acid cycle, and oxidative phosphorylation) were activated in MR-treated inguinal adipose tissue. In contrast, the effects of MR in liver involved up-regulation of anti-oxidant responses driven by the nuclear factor, erythroid 2 like 2 transcription factor, NFE2L2. Metabolomic analysis provided evidence for redox imbalance, stemming from large reductions in the master anti-oxidant molecule glutathione coupled with disproportionate increases in ophthalmate and its precursors, glutamate and 2-aminobutyrate. Thus, cysteine and its downstream product, glutathione, emerge as key early hepatic signaling molecules linking dietary MR to its metabolic phenotype. PMID:28520765

DNA Repair Alterations in Children With Pediatric Malignancies: Novel Opportunities to Identify Patients at Risk for High-Grade Toxicities

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ruebe, Claudia E., E-mail: claudia.ruebe@uks.e; Fricke, Andreas; Schneider, Ruth

Purpose: To evaluate, in a pilot study, the phosphorylated H2AX ({gamma}H2AX) foci approach for identifying patients with double-strand break (DSB) repair deficiencies, who may overreact to DNA-damaging cancer therapy. Methods and Materials: The DSB repair capacity of children with solid cancers was analyzed compared with that of age-matched control children and correlated with treatment-related normal-tissue responses (n = 47). Double-strand break repair was investigated by counting {gamma}H2AX foci in blood lymphocytes at defined time points after irradiation of blood samples. Results: Whereas all healthy control children exhibited proficient DSB repair, 3 children with tumors revealed clearly impaired DSB repair capacities,more » and 2 of these repair-deficient children developed life-threatening or even lethal normal-tissue toxicities. The underlying mutations affecting regulatory factors involved in DNA repair pathways were identified. Moreover, significant differences in mean DSB repair capacity were observed between children with tumors and control children, suggesting that childhood cancer is based on genetic alterations affecting DSB repair function. Conclusions: Double-strand break repair alteration in children may predispose to cancer formation and may affect children's susceptibility to normal-tissue toxicities. Phosphorylated H2AX analysis of blood samples allows one to detect DSB repair deficiencies and thus enables identification of children at risk for high-grade toxicities.« less

Downregulation of MicroRNA-126 Contributes to the Failing Right Ventricle in Pulmonary Arterial Hypertension.

PubMed

Potus, François; Ruffenach, Grégoire; Dahou, Abdellaziz; Thebault, Christophe; Breuils-Bonnet, Sandra; Tremblay, Ève; Nadeau, Valérie; Paradis, Renée; Graydon, Colin; Wong, Ryan; Johnson, Ian; Paulin, Roxane; Lajoie, Annie C; Perron, Jean; Charbonneau, Eric; Joubert, Philippe; Pibarot, Philippe; Michelakis, Evangelos D; Provencher, Steeve; Bonnet, Sébastien

2015-09-08

Right ventricular (RV) failure is the most important factor of both morbidity and mortality in pulmonary arterial hypertension (PAH). However, the underlying mechanisms resulting in the failed RV in PAH remain unknown. There is growing evidence that angiogenesis and microRNAs are involved in PAH-associated RV failure. We hypothesized that microRNA-126 (miR-126) downregulation decreases microvessel density and promotes the transition from a compensated to a decompensated RV in PAH. We studied RV free wall tissues from humans with normal RV (n=17), those with compensated RV hypertrophy (n=8), and patients with PAH with decompensated RV failure (n=14). Compared with RV tissues from patients with compensated RV hypertrophy, patients with decompensated RV failure had decreased miR-126 expression (quantitative reverse transcription-polymerase chain reaction; P<0.01) and capillary density (CD31(+) immunofluorescence; P<0.001), whereas left ventricular tissues were not affected. miR-126 downregulation was associated with increased Sprouty-related EVH1 domain-containing protein 1 (SPRED-1), leading to decreased activation of RAF (phosphorylated RAF/RAF) and mitogen-activated protein kinase (MAPK); (phosphorylated MAPK/MAPK), thus inhibiting the vascular endothelial growth factor pathway. In vitro, Matrigel assay showed that miR-126 upregulation increased angiogenesis of primary cultured endothelial cells from patients with decompensated RV failure. Furthermore, in vivo miR-126 upregulation (mimic intravenous injection) improved cardiac vascular density and function of monocrotaline-induced PAH animals. RV failure in PAH is associated with a specific molecular signature within the RV, contributing to a decrease in RV vascular density and promoting the progression to RV failure. More importantly, miR-126 upregulation in the RV improves microvessel density and RV function in experimental PAH. © 2015 American Heart Association, Inc.

Complex engagement of DNA damage response pathways in human cancer and in lung tumor progression.

PubMed

Nuciforo, Paolo Giovanni; Luise, Chiara; Capra, Maria; Pelosi, Giuseppe; d'Adda di Fagagna, Fabrizio

2007-10-01

Tumor initiation and progression provide a multitude of occasions for the generation of DNA damage and the consequent activation of the DNA damage response (DDR) pathway. DDR signaling involves the engagement of key factors such as ATM, CHK2, 53BP1 and the phosphorylation of histone H2AX (gamma-H2AX). The systematic study of DDR in human tumors and normal tissues by high-throughput tissue microarrays revealed that ATM and gamma-H2AX were engaged in cancer but the extent of their activation was strongly affected by the organ and cell type involved, whereas 53BP1 loss was the most consistent feature among the tumor studied. Unexpectedly, we also observed activated DDR markers in morphologically normal tissues, also in association with inflammation. Analysis of the dynamic engagement of DDR along the different stages of lung tumorigenesis showed that 53BP1 loss occurs early at the transition from normal to dysplastic change whereas the activated forms of ATM and CHK2, but not gamma-H2AX, initially accumulate in pre-invasive lesions and are then lost during tumor progression. In individual lung tumors, the activation of ATM, CHK2 and the presence of 53BP1 were consistently correlated, whereas gamma-H2AX did not correlate with activated ATM. Finally, the study of associations between critical clinicopathological parameters and activated DDR factors highlighted a statistically meaningful correlation between reduced local tumor extension and the phosphorylation of ATM, CHK2 and the presence of 53BP1, whereas no significant correlations with parameters such as survival or relapse of early-stage lung carcinomas were found.

High intensity interval training improves liver and adipose tissue insulin sensitivity.

PubMed

Marcinko, Katarina; Sikkema, Sarah R; Samaan, M Constantine; Kemp, Bruce E; Fullerton, Morgan D; Steinberg, Gregory R

2015-12-01

Endurance exercise training reduces insulin resistance, adipose tissue inflammation and non-alcoholic fatty liver disease (NAFLD), an effect often associated with modest weight loss. Recent studies have indicated that high-intensity interval training (HIIT) lowers blood glucose in individuals with type 2 diabetes independently of weight loss; however, the organs affected and mechanisms mediating the glucose lowering effects are not known. Intense exercise increases phosphorylation and inhibition of acetyl-CoA carboxylase (ACC) by AMP-activated protein kinase (AMPK) in muscle, adipose tissue and liver. AMPK and ACC are key enzymes regulating fatty acid metabolism, liver fat content, adipose tissue inflammation and insulin sensitivity but the importance of this pathway in regulating insulin sensitivity with HIIT is unknown. In the current study, the effects of 6 weeks of HIIT were examined using obese mice with serine-alanine knock-in mutations on the AMPK phosphorylation sites of ACC1 and ACC2 (AccDKI) or wild-type (WT) controls. HIIT lowered blood glucose and increased exercise capacity, food intake, basal activity levels, carbohydrate oxidation and liver and adipose tissue insulin sensitivity in HFD-fed WT and AccDKI mice. These changes occurred independently of weight loss or reductions in adiposity, inflammation and liver lipid content. These data indicate that HIIT lowers blood glucose levels by improving adipose and liver insulin sensitivity independently of changes in adiposity, adipose tissue inflammation, liver lipid content or AMPK phosphorylation of ACC.

Grape powder consumption affects the expression of neurodegeneration-related brain proteins in rats chronically fed a high-fructose-high-fat diet.

PubMed

Liao, Hsiang; Chou, Liang-Mao; Chien, Yi-Wen; Wu, Chi-Hao; Chang, Jung-Su; Lin, Ching-I; Lin, Shyh-Hsiang

2017-05-01

Abnormal glucose metabolism in the brain is recognized to be associated with cognitive decline. Because grapes are rich in polyphenols that produce antioxidative and blood sugar-lowering effects, we investigated how grape consumption affects the expression and/or phosphorylation of neurodegeneration-related brain proteins in aged rats fed a high-fructose-high-fat (HFHF) diet. Wistar rats were maintained on the HFHF diet from the age of 8 weeks to 66 weeks, and then on an HFHF diet containing either 3% or 6% grape powder as an intervention for 12 weeks. Western blotting was performed to measure the expression/phosphorylation levels of several cortical and hippocampal proteins, including amyloid precursor protein (APP), tau, phosphatidylinositol-3-kinase (PI3K), extracellular signal-regulated kinase (ERK), receptor for advanced glycation end products (RAGEs), erythroid 2-related factor 2 (Nrf2) and brain-derived neurotrophic factor (BDNF). Inclusion of up to 6% grape powder in the diet markedly reduced RAGE expression and tau hyperphosphorylation, but upregulated the expression of Nrf2 and BDNF, as well as the phosphorylation of PI3K and ERK, in the brain tissues of aged rats fed the HFHF diet. Thus, grape powder consumption produced beneficial effects in HFHF-diet-fed rats, exhibiting the potential to ameliorate changes in neurodegeneration-related proteins in the brain. Copyright © 2017 Elsevier Inc. All rights reserved.

Unremitting Cell Proliferation in the Secretory Phase of Eutopic Endometriosis

PubMed Central

Franco-Murillo, Yanira; Miranda-Rodríguez, José Antonio; Rendón-Huerta, Erika; Montaño, Luis F.; Cornejo, Gerardo Velázquez; Gómez, Lucila Poblano; Valdez-Morales, Francisco Javier; Gonzalez-Sanchez, Ignacio

2014-01-01

Objective: Endometriosis is linked to altered cell proliferation and stem cell markers c-kit/stem cell factor (SCF) in ectopic endometrium. Our aim was to investigate whether c-kit/SCF also plays a role in eutopic endometrium. Design: Eutopic endometrium obtained from 35 women with endometriosis and 25 fertile eumenorrheic women was analyzed for in situ expression of SCF/c-kit, Ki67, RAC-alpha serine/threonine-protein kinase (Akt), phosphorylated RAC-alpha serine/threonin-protein kinase (pAkt), Glycogen synthase kinase 3 beta (GSK3β), and phosphorylated glycogen synthase kinase 3 beta (pGSK3β), throughout the menstrual cycle. Results: Expression of Ki67 and SCF was higher in endometriosis than in control tissue (P < .05) and greater in secretory rather than proliferative (P < .01) endometrium in endometriosis. Expression of c-kit was also higher in endometriosis although similar in both phases. Expression of Akt and GSK3β was identical in all samples and cycle phases, whereas pAkt and pGSK3β, opposed to control tissue, remained overexpressed in the secretory phase in endometriosis. Conclusion: Unceasing cell proliferation in the secretory phase of eutopic endometriosis is linked to deregulation of c-kit/SCF-associated signaling pathways. PMID:25194152

Glucose-derived AGEs enhance human gastric cancer metastasis through RAGE/ERK/Sp1/MMP2 cascade.

PubMed

Deng, Ruyuan; Mo, Fengbo; Chang, Bowen; Zhang, Qi; Ran, Hui; Yang, Shuhua; Zhu, Zhiqiang; Hu, Lei; Su, Qing

2017-11-28

Advanced glycation end products (AGEs) have been reported to take part in many cancer processes. Whether AGEs contribute to gastric cancer (GC) course and the underlying mechanism are still unclear. Here, glucose-derived AGEs are detected to be accumulated in tumor tissues and blood of patients with GC. As the receptor for AGEs, RAGE is highly expressed in cancer tissues, and closely associated with the depth of cancer invasion, lymph node metastasis and TNM stage. Both in vivo and in vitro treatment of AGEs accelerate the tumor invasion and metastasis, with upregualtion of RAGE, Specificity Protein 1 (Sp1), and MMP2 protein expression, as well as enhancement of MMP2 activity. Either RAGE-blocking antibody or Sp1-knockdown can partially block the AGEs-induced effects. Moreover, AGEs increased the phosphorylation of ERK, and reducing the phosphorylation level of ERK by MEK1/2 inhibitor decreased the expression of Sp1. These results indicate that accumulation of glucose-derived AGEs may act as one of potential risk factors for GC progression and promote the invasion and metastasis of gastric cancer partially through the activation of RAGE/ERK/Sp1/MMP2 pathway.

Glucose-derived AGEs enhance human gastric cancer metastasis through RAGE/ERK/Sp1/MMP2 cascade

PubMed Central

Deng, Ruyuan; Mo, Fengbo; Chang, Bowen; Zhang, Qi; Ran, Hui; Yang, Shuhua; Zhu, Zhiqiang; Hu, Lei; Su, Qing

2017-01-01

Advanced glycation end products (AGEs) have been reported to take part in many cancer processes. Whether AGEs contribute to gastric cancer (GC) course and the underlying mechanism are still unclear. Here, glucose-derived AGEs are detected to be accumulated in tumor tissues and blood of patients with GC. As the receptor for AGEs, RAGE is highly expressed in cancer tissues, and closely associated with the depth of cancer invasion, lymph node metastasis and TNM stage. Both in vivo and in vitro treatment of AGEs accelerate the tumor invasion and metastasis, with upregualtion of RAGE, Specificity Protein 1 (Sp1), and MMP2 protein expression, as well as enhancement of MMP2 activity. Either RAGE-blocking antibody or Sp1-knockdown can partially block the AGEs-induced effects. Moreover, AGEs increased the phosphorylation of ERK, and reducing the phosphorylation level of ERK by MEK1/2 inhibitor decreased the expression of Sp1. These results indicate that accumulation of glucose-derived AGEs may act as one of potential risk factors for GC progression and promote the invasion and metastasis of gastric cancer partially through the activation of RAGE/ERK/Sp1/MMP2 pathway. PMID:29262634

Transforming growth factor-beta1 mediates cellular response to DNA damage in situ

NASA Technical Reports Server (NTRS)

Ewan, Kenneth B.; Henshall-Powell, Rhonda L.; Ravani, Shraddha A.; Pajares, Maria Jose; Arteaga, Carlos; Warters, Ray; Akhurst, Rosemary J.; Barcellos-Hoff, Mary Helen

2002-01-01

Transforming growth factor (TGF)-beta1 is rapidly activated after ionizing radiation, but its specific role in cellular responses to DNA damage is not known. Here we use Tgfbeta1 knockout mice to show that radiation-induced apoptotic response is TGF-beta1 dependent in the mammary epithelium, and that both apoptosis and inhibition of proliferation in response to DNA damage decrease as a function of TGF-beta1 gene dose in embryonic epithelial tissues. Because apoptosis in these tissues has been shown previously to be p53 dependent, we then examined p53 protein activation. TGF-beta1 depletion, by either gene knockout or by using TGF-beta neutralizing antibodies, resulted in decreased p53 Ser-18 phosphorylation in irradiated mammary gland. These data indicate that TGF-beta1 is essential for rapid p53-mediated cellular responses that mediate cell fate decisions in situ.

Organic acid component from Taraxacum mongolicum Hand.-Mazz alleviates inflammatory injury in lipopolysaccharide-induced acute tracheobronchitis of ICR mice through TLR4/NF-κB signaling pathway.

PubMed

Yang, Nan; Li, Chao; Tian, Gang; Zhu, Maomao; Bu, Weiquan; Chen, Juan; Hou, Xuefeng; Di, Liuqing; Jia, Xiaobin; Dong, Zibo; Feng, Liang

2016-05-01

Inflammation plays an important role in the pathogenesis of acute tracheobronchitis. Taraxacum mongolicum Hand.-Mazz (TMHM) is a dietic herb for heat-clearing and detoxifying functions as well as swell-reducing and mass-resolving effect in Traditional Chinese Medicine. Studies have shown that its major ingredient organic acid component (OAC) possesses favorable anti-inflammatory activity. However, the protective effect of OAC from TMHM (TMHM-OAC) on inflammatory injury of acute tracheobronchitis and its possible mechanism remains poorly understood. In this study, HPLC-DAD was used to analyze the components of TMHM-OAC. Lipopolysaccharide of 1mg/ml was used to induce respiratory inflammation in ICR mice at the dose of 5mg/kg by intratracheally aerosol administration. Enzyme-linked immunosorbent assay (ELISA) was employed to detect the levels of inflammation factors such as interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), and nitric oxide in serum and supernatant of trachea tissue. Western blotting (WB) and Immunohistochemistry analysis (IHC) were conducted in parallel to determine TNF-α, IL-6, inducible nitric oxide synthase (iNOS), Toll-like receptors 4(TLR4) protein expressions and nuclear factor-kappa B p65 (NF-κB p65) phosphorylation. Hematoxylin-Eosin staining (HE) was applied to evaluate pathological lesions of trachea tissue. Experimental results showed that TMHM-OAC significantly reduced the levels of the TNF-α, IL-6 and NO in serum and supernatant of tracheal of LPS-induced ICR mice. The protein expression levels of TNF-α, IL-6 and iNOS in tracheal tissue were also down-regulated significantly by the treatment of TMHM-OAC. Moreover, TMHM-OAC downregulated phosphorylation of NF-κB p65 and protein expression of TLR4. Our results indicated that TMHM-OAC could improve LPS-induced histopathological damage of tracheal tissues through the regulation of TLR4/NF-κB signaling pathway and could be beneficial for the treatment of acute tracheobronchitis. Copyright © 2016 Elsevier B.V. All rights reserved.

Compound Astragalus and Salvia miltiorrhiza extracts suppress hepatocarcinogenesis by modulating transforming growth factor-β/Smad signaling.

PubMed

Hu, Xiangpeng; Rui, Wenjuan; Wu, Chao; He, Shufang; Jiang, Jiemei; Zhang, Xiaoxiang; Yang, Yan

2014-06-01

Previous studies showed Compound Astragalus and Salvia miltiorrhiza extract (CASE), extract from Astragalus membranaceus and Salvia miltiorhiza, significantly suppresses hepatocellular carcinoma (HCC) in rats induced by diethylinitrosamine (DEN), and in vitro experiments further demonstrated that CASE's anti-HepG2 cell invasion is associated with transforming growth factor-β (TGF-β). We hypothesized that CASE's suppression of HCC is modulated by TGF-β/Smad signaling, and we conducted this in vivo study to test this hypothesis. Rats were divided into the normal control, the DEN group, and three CASE (60, 120, and 240 mg/kg) treatment groups. The expression of phosphorylation(p) Smad both at C-terminal and linker region, plasminogen activator inhibitor 1, and Smad4 and Smad7 of liver tissues were measured and compared across the five groups. The positive staining of pSmad2L and pSmad3L increased both in hepatoma nodule areas and adjacent relatively normal liver tissues in rats treated with DEN, while the positive staining of pSmad2C and pSmad3C increased only in relatively normal liver tissues adjacent to hepatoma tissues. The elevated expression of pSmad2C, pSmad2L, pSmad3L, Smad4, and plasminogen activator inhibitor 1 proteins were suppressed by CASE in a dose-dependent manner. CASE treatment also significantly reduced the intranuclear amounts of pSmad2L and pSmad3L, and upregulated the elevation of pSmad3C positive cells and protein expression in a dose-dependent manner. The results suggest that CASE significantly suppresses HCC progression by mediating TGF-β/Smad signaling, especially by modulating Smad3 phosphorylation both at the C-terminal and linker region. © 2013 Journal of Gastroenterology and Hepatology Foundation and Wiley Publishing Asia Pty Ltd.

Coprinus comatus Cap Inhibits Adipocyte Differentiation via Regulation of PPARγ and Akt Signaling Pathway

PubMed Central

Jang, Sun-Hee; Kang, Suk Nam; Jeon, Beong-Sam; Ko, Yeoung-Gyu; Kim, Hong-Duck; Won, Chung-Kil; Kim, Gon-Sup; Cho, Jae-Hyeon

2014-01-01

This study assessed the effects of Coprinus comatus cap (CCC) on adipogenesis in 3T3-L1 adipocytes and the effects of CCC on the development of diet-induced obesity in rats. Here, we showed that the CCC has an inhibitory effect on the adipocyte differentiation of 3T3-L1 cells, resulting in a significant decrease in lipid accumulation through the downregulation of several adipocyte specific-transcription factors, including CCAAT/enhancer binding protein β, C/EBPδ, and peroxisome proliferator-activated receptor gamma (PPARγ). Moreover, treatment with CCC during adipocyte differentiation induced a significant down-regulation of PPARγ and adipogenic target genes, including adipocyte protein 2, lipoprotein lipase, and adiponectin. Interestingly, the CCC treatment of the 3T3-L1 adipocytes suppressed the insulin-stimulated Akt and GSK3β phosphorylation, and these effects were stronger in the presence of an inhibitor of Akt phosphorylation, LY294002, suggesting that CCC inhibited adipocyte differentiation through the down-regulation of Akt signaling. In the animal study, CCC administration significantly reduced the body weight and adipose tissue weight of rats fed a high fat diet (HFD) and attenuated lipid accumulation in the adipose tissues of the HFD-induced obese rats. The size of the adipocyte in the epididymal fat of the CCC fed rats was significantly smaller than in the HFD rats. CCC treatment significantly reduced the total cholesterol and triglyceride levels in the serum of HFD rats. These results strongly indicated that the CCC-mediated decrease in body weight was due to a reduction in adipose tissue mass. The expression level of PPARγ and phospho-Akt was significantly lower in the CCC-treated HFD rats than that in the HFD obesity rats. These results suggested that CCC inhibited adipocyte differentiation by the down-regulation of major transcription factor involved in the adipogenesis pathway including PPARγ through the regulation of the Akt pathway in 3T3-L1 cells and HFD adipose tissue. PMID:25181477

A systems biology approach to the pathogenesis of obesity-related nonalcoholic fatty liver disease using reverse phase protein microarrays for multiplexed cell signaling analysis.

PubMed

Calvert, Valerie S; Collantes, Rochelle; Elariny, Hazem; Afendy, Arian; Baranova, Ancha; Mendoza, Michael; Goodman, Zachary; Liotta, Lance A; Petricoin, Emanuel F; Younossi, Zobair M

2007-07-01

Nonalcoholic fatty liver disease (NAFLD) is a common cause of chronic liver disease. Omental adipose tissue, a biologically active organ secreting adipokines and cytokines, may play a role in the development of NAFLD. We tested this hypothesis with reverse-phase protein microarrays (RPA) for multiplexed cell signaling analysis of adipose tissue from patients with NAFLD. Omental adipose tissue was obtained from 99 obese patients. Liver biopsies obtained at the time of surgery were all read by the same hepatopathologist. Adipose tissue was exposed to rapid pressure cycles to extract protein lysates. RPA was used to investigate intracellular signaling. Analysis of 54 different kinase substrates and cell signaling endpoints showed that an insulin signaling pathway is deranged in different locations in NAFLD patients. Furthermore, components of insulin receptor-mediated signaling differentiate most of the conditions on the NAFLD spectrum. For example, PKA (protein kinase A) and AKT/mTOR (protein kinase B/mammalian target of rapamycin) pathway derangement accurately discriminates patients with NASH from those with the non-progressive forms of NAFLD. PKC (protein kinase C) delta, AKT, and SHC phosphorylation changes occur in patients with simple steatosis. Amounts of the FKHR (forkhead factor Foxo1)phosphorylated at S256 residue were significantly correlated with AST/ALT ratio in all morbidly obese patients. Furthermore, amounts of cleaved caspase 9 and pp90RSK S380 were positively correlated in patients with NASH. Specific insulin pathway signaling events are altered in the adipose tissue of patients with NASH compared with patients with nonprogressive forms of NAFLD. These findings provide evidence for the role of omental fat in the pathogenesis, and potentially, the progression of NAFLD.

Anti-fibrotic effects of pirfenidone by interference with the hedgehog signalling pathway in patients with systemic sclerosis-associated interstitial lung disease.

PubMed

Xiao, Hua; Zhang, Guang-Feng; Liao, Xiang-Ping; Li, Xiao-Jie; Zhang, Jian; Lin, Haobo; Chen, Zhe; Zhang, Xiao

2018-02-01

To determine whether pirfenidone attenuates lung fibrosis by interfering with the hedgehog (Hh) signalling pathway in patients with systemic sclerosis-associated interstitial lung disease (SSc-ILD). Twenty-five SSc-ILD patients (20 first visit, five who underwent pirfenidone treatment for 6 months) and 10 healthy controls were recruited. Lung tissues were obtained by open-chest surgery, and primary lung fibroblasts were isolated, cultured and stimulated with pirfenidone. The levels of the proteins glioma-associated oncogene 1 (GLI1), suppressor of fused (Sufu), α-smooth muscle actin, and fibronectin in lung tissues or fibroblasts were determined by Western blotting. The messenger RNA levels of GLI1, glioma-associated oncogene 2, protein patched homolog 1, and Sufu in lung tissues or fibroblasts were determined by quantitative reverse-transcription polymerase chain reaction. Meanwhile, the levels of phosphorylation glycogen synthase kinasep-3β (pGSK-3β), phosphorylation SMAD2 (pSMAD2), and phosphorylation c-Jun N-terminal kinase (pJNK) in fibroblasts were determined by Western blotting. Hh pathway activation was increased in the lung tissue of SSc-ILD patients and was decreased by pirfenidone, Sufu was upregulated in lung fibroblasts isolated from SSc-ILD patients after pirfenidone challenge, and pirfenidone inhibited the phosphorylation of GSK-3β signalling. Pirfenidone has anti-fibrotic effects in SSc-ILD patients by interfering with both the Hh signalling pathway and the GSK-3β signalling pathway via the regulation of Sufu expression. These results might promote its use in other Hh driven lung diseases such as idiopathic pulmonary fibrosis and especially the interstitial lung disease associated with connective tissue diseases. © 2018 Asia Pacific League of Associations for Rheumatology and John Wiley & Sons Australia, Ltd.

ERK1/2/MAPK pathway-dependent regulation of the telomeric factor TRF2

PubMed Central

Picco, Vincent; Coste, Isabelle; Giraud-Panis, Marie-Josèphe; Renno, Toufic; Gilson, Eric; Pagès, Gilles

2016-01-01

Telomere stability is a hallmark of immortalized cells, including cancer cells. While the telomere length is maintained in most cases by the telomerase, the activity of a protein complex called Shelterin is required to protect telomeres against unsuitable activation of the DNA damage response pathway. Within this complex, telomeric repeat binding factor 2 (TRF2) plays an essential role by blocking the ataxia telangiectasia-mutated protein (ATM) signaling pathway at telomeres and preventing chromosome end fusion. We showed that TRF2 was phosphorylated in vitro and in vivo on serine 323 by extracellular signal-regulated kinase (ERK1/2) in both normal and cancer cells. Moreover, TRF2 and activated ERK1/2 unexpectedly interacted in the cytoplasm of tumor cells and human tumor tissues. The expression of non-phosphorylatable forms of TRF2 in melanoma cells induced the DNA damage response, leading to growth arrest and tumor reversion. These findings revealed that the telomere stability is under direct control of one of the major pro-oncogenic signaling pathways (RAS/RAF/MEK/ERK) via TRF2 phosphorylation. PMID:27366950

Brain derived neurotrophic factor is involved in the regulation of glycogen synthase kinase 3β (GSK3β) signalling

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gupta, Vivek, E-mail: vivek.gupta@mq.edu.au; Chitranshi, Nitin; You, Yuyi

2014-11-21

Highlights: • BDNF knockdown leads to activation of GSK3β in the neuronal cells. • BDNF knockdown can induce GSK3β activation beyond TrkB mediated effects. • BDNF impairment in vivo leads to age dependent activation of GSK3β in the retina. • Systemic treatment with TrkB agonist induces inhibition of retinal GSK3β. - Abstract: Glycogen synthase kinase 3β (GSK3β) is involved in several biochemical processes in neurons regulating cellular survival, gene expression, cell fate determination, metabolism and proliferation. GSK3β activity is inhibited through the phosphorylation of its Ser-9 residue. In this study we sought to investigate the role of BDNF/TrkB signalling inmore » the modulation of GSK3β activity. BDNF/TrkB signalling regulates the GSK3β activity both in vivo in the retinal tissue as well as in the neuronal cells under culture conditions. We report here for the first time that BDNF can also regulate GSK3β activity independent of its effects through the TrkB receptor signalling. Knockdown of BDNF lead to a decline in GSK3β phosphorylation without having a detectable effect on the TrkB activity or its downstream effectors Akt and Erk1/2. Treatment with TrkB receptor agonist had a stimulating effect on the GSK3β phosphorylation, but the effect was significantly less pronounced in the cells in which BDNF was knocked down. The use of TrkB receptor antagonist similarly, manifested itself in the form of downregulation of GSK3β phosphorylation, but a combined TrkB inhibition and BDNF knockdown exhibited a much stronger negative effect. In vivo, we observed reduced levels of GSK3β phosphorylation in the retinal tissues of the BDNF{sup +/−} animals implicating critical role of BDNF in the regulation of the GSK3β activity. Concluding, BDNF/TrkB axis strongly regulates the GSK3β activity and BDNF also exhibits GSK3β regulatory effect independent of its actions through the TrkB receptor signalling.« less

TRAF1 knockdown alleviates palmitate-induced insulin resistance in HepG2 cells through NF-κB pathway

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, Wanlu; Jiangsu Province Key Laboratory for Inflammation and Molecular Drug Target, Nantong University, 19 Qixiu Road, Nantong 226001, Jiangsu Province; Tang, Zhuqi

High-fat diet (HFD) and inflammation are key contributors to insulin resistance (IR) and Type 2 diabetes mellitus (T2DM). With HFD, plasma free fatty acids (FFAs) can activate the nuclear factor-κB (NF-κB) in target tissues, then initiate negative crosstalk between FFAs and insulin signaling. However, the molecular link between IR and inflammation remains to be identified. We here reported that tumor necrosis factor receptor-associated factor 1 (TRAF1), an adapter in signal transduction, was involved in the onset of IR in hepatocytes. TRAF1 was significantly up-regulated in insulin-resistant liver tissues and palmitate (PA)-treated HepG2 cells. In addition, we showed that depletion ofmore » TRAF1 led to inhibition of the activity of NF-κB. Given the fact that the activation of NF-κB played a facilitating role in IR, the phosphorylation of Akt and GSK3β was also analyzed. We found that depletion of TRAF1 markedly reversed PA-induced attenuation of the phosphorylation of Akt and GSK3β in the cells. The accumulation of lipid droplets in hepatocyte and expression of two key gluconeogenic enzymes, PEPCK and G6Pase, were also determined and found to display a similar tendency with the phosphorylation of Akt and GSK3β. Glucose uptake assay indicated that knocking down TRAF1 blocked the effect of PA on the suppression of glucose uptake. These data implicated that TRAF1 knockdown might alleviate PA-induced IR in HepG2 cells through NF-κB pathway. - Highlights: • TRAF1 accelerated PA-induced IR in HepG2 cells mediated through NF-κB signaling. • Knockdown of TRAF1 alleviated PA-induced IR in HepG2 cells. • Knockdown of TRAF1 alleviated PA-induced lipid accumulation in HepG2 cells. • Knockdown of TRAF1 reversed PA-induced suppression of glucose uptake in HepG2 cells. • Knockdown of TRAF1 reversed PA-induced gluconeogenesis in HepG2 cells.« less

p130Cas-associated Protein (p140Cap) as a New Tyrosine-phosphorylated Protein Involved in Cell Spreading

PubMed Central

Di Stefano, Paola; Cabodi, Sara; Erba, Elisabetta Boeri; Margaria, Valentina; Bergatto, Elena; Giuffrida, Maria Gabriella; Silengo, Lorenzo; Tarone, Guido; Turco, Emilia; Defilippi, Paola

2004-01-01

Integrin-mediated cell adhesion stimulates a cascade of signaling pathways that control cell proliferation, migration, and survival, mostly through tyrosine phosphorylation of signaling molecules. p130Cas, originally identified as a major substrate of v-Src, is a scaffold molecule that interacts with several proteins and mediates multiple cellular events after cell adhesion and mitogen treatment. Here, we describe a novel p130Cas-associated protein named p140Cap (Cas-associated protein) as a new tyrosine phosphorylated molecule involved in integrin- and epidermal growth factor (EGF)-dependent signaling. By affinity chromatography of human ECV304 cell extracts on a MBP-p130Cas column followed by mass spectrometry matrix-assisted laser desorption ionization/time of flight analysis, we identified p140Cap as a protein migrating at 140 kDa. We detected its expression in human, mouse, and rat cells and in different mouse tissues. Endogenous and transfected p140Cap proteins coimmunoprecipitate with p130Cas in ECV304 and in human embryonic kidney 293 cells and associate with p130Cas through their carboxy-terminal region. By immunofluorescence analysis, we demonstrated that in ECV304 cells plated on fibronectin, the endogenous p140Cap colocalizes with p130Cas in the perinuclear region as well as in lamellipodia. In addition p140Cap codistributes with cortical actin and actin stress fibers but not with focal adhesions. We also show that p140Cap is tyrosine phosphorylated within 15 min of cell adhesion to integrin ligands. p140Cap tyrosine phosphorylation is also induced in response to EGF through an EGF receptor dependent-mechanism. Interestingly expression of p140Cap in NIH3T3 and in ECV304 cells delays the onset of cell spreading in the early phases of cell adhesion to fibronectin. Therefore, p140Cap is a novel protein associated with p130Cas and actin cytoskeletal structures. Its tyrosine phosphorylation by integrin-mediated adhesion and EGF stimulation and its involvement in cell spreading on matrix proteins suggest that p140Cap plays a role in controlling actin cytoskeleton organization in response to adhesive and growth factor signaling. PMID:14657239

Redox regulation of antioxidant enzymes: post-translational modulation of catalase and glutathione peroxidase activity by resveratrol in diabetic rat liver.

PubMed

Sadi, Gökhan; Bozan, Davut; Yildiz, Huseyin Bekir

2014-08-01

Resveratrol is a strong antioxidant that exhibits blood glucose-lowering effects, which might contribute to its usefulness in preventing complications associated with diabetes. The present study aimed to investigate resveratrol effects on catalase (CAT) and glutathione peroxidase (GPx) gene and protein expression, their phosphorylation states and activities in rat liver of STZ-induced diabetes. Diabetes increased the levels of total protein phosphorylation and p-CAT, while mRNA expression, protein levels, and activity were reduced. Although diabetes induced transcriptional repression over GPx, it did not affect the protein levels and activity. When resveratrol was administered to diabetic rats, an increase in activity was associated with an increase in p-GPx levels. Decrease in Sirtuin1 (SIRT1) and nuclear factor erythroid 2-related factor (Nrf2) and increase in nuclear factor kappa B (NFκB) gene expression in diabetes were associated with a decrease in CAT and GPx mRNA expression. A possible compensatory mechanism for reduced gene expression of antioxidant enzymes is proved to be nuclear translocation of redox-sensitive Nrf2 and NFκB in diabetes which is confirmed by the increase in nuclear and decrease in cytoplasmic protein levels of Nrf2 and NFκB. Taken together, these findings revealed that an increase in the oxidized state in diabetes intricately modified the cellular phosphorylation status and regulation of antioxidant enzymes. Gene regulation of antioxidant enzymes was accompanied by nuclear translocation of Nrf2 and NFκB. Resveratrol administration also activated a coordinated cytoprotective response against diabetes-induced changes in liver tissues.

BCL-2 family protein, BAD is down-regulated in breast cancer and inhibits cell invasion

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cekanova, Maria, E-mail: mcekanov@utk.edu; Fernando, Romaine I.; Siriwardhana, Nalin

We have previously demonstrated that the anti-apoptotic protein BAD is expressed in normal human breast tissue and shown that BAD inhibits expression of cyclin D1 to delay cell-cycle progression in breast cancer cells. Herein, expression of proteins in breast tissues was studied by immunohistochemistry and results were analyzed statistically to obtain semi-quantitative data. Biochemical and functional changes in BAD-overexpressing MCF7 breast cancer cells were evaluated using PCR, reporter assays, western blotting, ELISA and extracellular matrix invasion assays. Compared to normal tissues, Grade II breast cancers expressed low total/phosphorylated forms of BAD in both cytoplasmic and nuclear compartments. BAD overexpression decreasedmore » the expression of β-catenin, Sp1, and phosphorylation of STATs. BAD inhibited Ras/MEK/ERK and JNK signaling pathways, without affecting the p38 signaling pathway. Expression of the metastasis-related proteins, MMP10, VEGF, SNAIL, CXCR4, E-cadherin and TlMP2 was regulated by BAD with concomitant inhibition of extracellular matrix invasion. Inhibition of BAD by siRNA increased invasion and Akt/p-Akt levels. Clinical data and the results herein suggest that in addition to the effect on apoptosis, BAD conveys anti-metastatic effects and is a valuable prognostic marker in breast cancer. - Highlights: • BAD and p-BAD expressions are decreased in breast cancer compared with normal breast tissue. • BAD impedes breast cancer invasion and migration. • BAD inhibits the EMT and transcription factors that promote cancer cell migration. • Invasion and migration functions of BAD are distinct from the BAD's role in apoptosis.« less

Analysis of TNF-related apoptosis-inducing ligand and receptors and implications in thymus biology and myasthenia gravis.

PubMed

Kanatli, Irem; Akkaya, Bahar; Uysal, Hilmi; Kahraman, Sevim; Sanlioglu, Ahter Dilsad

2017-02-01

Myasthenia Gravis is an autoantibody-mediated, neuromuscular junction disease, and is usually associated with thymic abnormalities presented as thymic tumors (~10%) or hyperplastic thymus (~65%). The exact role of thymus in Myasthenia Gravis development is not clear, yet many patients benefit from thymectomy. The apoptotic ligand TNF-Related Apoptosis-Inducing Ligand is thought to be involved in the regulation of thymocyte counts, although conflicting results are reported. We investigated differential expression profiles of TNF-Related Apoptosis-Inducing Ligand and its transmembrane receptors, Nuclear Factor-kB activation status, and apoptotic cell counts in healthy thymic tissue and pathological thymus from Myasthenia Gravis patients. All tissues expressed TNF-Related Apoptosis-Inducing Ligand and its receptors, with hyperplastic tissue having the highest expression levels of death receptors DR4 and DR5. No detectable Nuclear Factor-kB activation, at least via the canonical Protein Kinase A-mediated p65 Ser276 phosphorylation, was evident in any of the tissues studied. Apoptotic cell counts were higher in MG-associated tissue compared to the normal thymus. Possible use of the TNF-Related Apoptosis-Inducing Ligand within the concept of an apoptotic ligand-mediated medical thymectomy in thymoma- or thymic hyperplasia-associated Myasthenia Gravis is also discussed. Copyright © 2016 Elsevier B.V. All rights reserved.

Oxidative stress accumulates in adipose tissue during aging and inhibits adipogenesis.

PubMed

Findeisen, Hannes M; Pearson, Kevin J; Gizard, Florence; Zhao, Yue; Qing, Hua; Jones, Karrie L; Cohn, Dianne; Heywood, Elizabeth B; de Cabo, Rafael; Bruemmer, Dennis

2011-04-14

Aging constitutes a major independent risk factor for the development of type 2 diabetes and is accompanied by insulin resistance and adipose tissue dysfunction. One of the most important factors implicitly linked to aging and age-related chronic diseases is the accumulation of oxidative stress. However, the effect of increased oxidative stress on adipose tissue biology remains elusive. In this study, we demonstrate that aging in mice results in a loss of fat mass and the accumulation of oxidative stress in adipose tissue. In vitro, increased oxidative stress through glutathione depletion inhibits preadipocyte differentiation. This inhibition of adipogenesis is at least in part the result of reduced cell proliferation and an inhibition of G(1)→S-phase transition during the initial mitotic clonal expansion of the adipocyte differentiation process. While phosphorylation of the retinoblastoma protein (Rb) by cyclin/cdk complexes remains unaffected, oxidative stress decreases the expression of S-phase genes downstream of Rb. This silencing of S phase gene expression by increased oxidative stress is mediated through a transcriptional mechanism involving the inhibition of E2F recruitment and transactivation of its target promoters. Collectively, these data demonstrate a previously unrecognized role of oxidative stress in the regulation of adipogenesis which may contribute to age-associated adipose tissue dysfunction.

Oxidative Stress Accumulates in Adipose Tissue during Aging and Inhibits Adipogenesis

PubMed Central

Findeisen, Hannes M.; Pearson, Kevin J.; Gizard, Florence; Zhao, Yue; Qing, Hua; Jones, Karrie L.; Cohn, Dianne; Heywood, Elizabeth B.; de Cabo, Rafael; Bruemmer, Dennis

2011-01-01

Aging constitutes a major independent risk factor for the development of type 2 diabetes and is accompanied by insulin resistance and adipose tissue dysfunction. One of the most important factors implicitly linked to aging and age-related chronic diseases is the accumulation of oxidative stress. However, the effect of increased oxidative stress on adipose tissue biology remains elusive. In this study, we demonstrate that aging in mice results in a loss of fat mass and the accumulation of oxidative stress in adipose tissue. In vitro, increased oxidative stress through glutathione depletion inhibits preadipocyte differentiation. This inhibition of adipogenesis is at least in part the result of reduced cell proliferation and an inhibition of G1→S-phase transition during the initial mitotic clonal expansion of the adipocyte differentiation process. While phosphorylation of the retinoblastoma protein (Rb) by cyclin/cdk complexes remains unaffected, oxidative stress decreases the expression of S-phase genes downstream of Rb. This silencing of S phase gene expression by increased oxidative stress is mediated through a transcriptional mechanism involving the inhibition of E2F recruitment and transactivation of its target promoters. Collectively, these data demonstrate a previously unrecognized role of oxidative stress in the regulation of adipogenesis which may contribute to age-associated adipose tissue dysfunction. PMID:21533223

Bioactive nanofibers for fibroblastic differentiation of mesenchymal precursor cells for ligament/tendon tissue engineering applications.

PubMed

Sahoo, Sambit; Ang, Lay-Teng; Cho-Hong Goh, James; Toh, Siew-Lok

2010-02-01

Mesenchymal stem cells and precursor cells are ideal candidates for tendon and ligament tissue engineering; however, for the stem cell-based approach to succeed, these cells would be required to proliferate and differentiate into tendon/ligament fibroblasts on the tissue engineering scaffold. Among the various fiber-based scaffolds that have been used in tendon/ligament tissue engineering, hybrid fibrous scaffolds comprising both microfibers and nanofibers have been recently shown to be particularly promising. With the nanofibrous coating presenting a biomimetic surface, the scaffolds can also potentially mimic the natural extracellular matrix in function by acting as a depot for sustained release of growth factors. In this study, we demonstrate that basic fibroblast growth factor (bFGF) could be successfully incorporated, randomly dispersed within blend-electrospun nanofibers and released in a bioactive form over 1 week. The released bioactive bFGF activated tyrosine phosphorylation signaling within seeded BMSCs. The bFGF-releasing nanofibrous scaffolds facilitated BMSC proliferation, upregulated gene expression of tendon/ligament-specific ECM proteins, increased production and deposition of collagen and tenascin-C, reduced multipotency of the BMSCs and induced tendon/ligament-like fibroblastic differentiation, indicating their potential in tendon/ligament tissue engineering applications. 2009 International Society of Differentiation. Published by Elsevier B.V. All rights reserved.

Interferon-γ alters downstream signaling originating from epidermal growth factor receptor in intestinal epithelial cells: functional consequences for ion transport.

PubMed

Paul, Gisela; Marchelletta, Ronald R; McCole, Declan F; Barrett, Kim E

2012-01-13

The epidermal growth factor receptor (EGFr) regulates many cellular functions, such as proliferation, apoptosis, and ion transport. Our aim was to investigate whether long term treatment with interferon-γ (IFN-γ) modulates EGF activation of downstream signaling pathways in intestinal epithelial cells and if this contributes to dysregulation of epithelial ion transport in inflammation. Polarized monolayers of T(84) and HT29/cl.19A colonocytes were preincubated with IFN-γ prior to stimulation with EGF. Basolateral potassium transport was studied in Ussing chambers. We also studied inflamed colonic mucosae from C57BL/6 mice treated with dextran sulfate sodium or mdr1a knock-out mice and controls. IFN-γ increased intestinal epithelial EGFr expression without increasing its phosphorylation. Conversely, IFN-γ caused a significant decrease in EGF-stimulated phosphorylation of specific EGFr tyrosine residues and activation of ERK but not Akt-1. In IFNγ-pretreated cells, the inhibitory effect of EGF on carbachol-stimulated K(+) channel activity was lost. In inflamed colonic tissues, EGFr expression was significantly increased, whereas ERK phosphorylation was reduced. Thus, although it up-regulates EGFr expression, IFN-γ causes defective EGFr activation in colonic epithelial cells via reduced phosphorylation of specific EGFr tyrosine residues. This probably accounts for altered downstream signaling consequences. These observations were corroborated in the setting of colitis. IFN-γ also abrogates the ability of EGF to inhibit carbachol-stimulated basolateral K(+) currents. Our data suggest that, in the setting of inflammation, the biological effect of EGF, including the inhibitory effect of EGF on Ca(2+)-dependent ion transport, is altered, perhaps contributing to diarrheal and other symptoms in vivo.

Inhibition of M1 macrophage activation in adipose tissue by berberine improves insulin resistance.

PubMed

Ye, Lifang; Liang, Shu; Guo, Chao; Yu, Xizhong; Zhao, Juan; Zhang, Hao; Shang, Wenbin

2016-12-01

Insulin resistance is associated with a chronic inflammation in adipose tissue which is propagated by a phenotypic switch in adipose tissue macrophage (ATM) polarization. This study aimed to investigate whether berberine, the major alkaloid of rhizoma coptidis, can improve insulin resistance through inhibiting ATM activation and inflammatory response in adipose tissue. High-fat-diet induced obese mice were administered oral with berberine (50mg/kg/day) for 14days. ATMs were analysed using FACS and insulin resistance was evaluated. Expressions of pro-inflammatory cytokines and activation of inflammatory pathways were detected. The chemotaxis of macrophages was measured. Glucose consumption and insulin signalling of adipocytes were examined. Berberine significantly decreased F4/80 + /CD11c + /CD206 - cells in the stromal vascular fraction from adipose tissue and improved glucose tolerance in obsess mice. In addition, berberine reduced the elevated levels of serum TNF-α, IL-6 and MCP-1 and the expressions of TNF-α, IL-6 and MCP-1 and attenuated the phosphorylation of JNK and IKKβ and the expression of NF-κB p65 in the obese adipose tissue, Raw264.7 macrophages and 3T3-L1 adipocytes, respectively. The phosphorylation of IRS-1 (Ser307) was inhibited by berberine in adipose tissue and cultured adipocytes. The phosphorylation of AKT (Ser473) was increased in berberine-treated adipose tissue. Conditioned medium from adipocytes treated with berberine reduced the number of infiltrated macrophages. Berberine partly restored the impaired glucose consumption and the activation of IRS-1 (Ser307) in adipocytes induced by the activation of macrophages. Our findings imply that berberine improves insulin resistance by inhibiting M1 macrophage activation in adipose tissue. Copyright © 2016 Elsevier Inc. All rights reserved.

Nuclear alternate estrogen receptor GPR30 mediates 17beta-estradiol-induced gene expression and migration in breast cancer-associated fibroblasts.

PubMed

Madeo, Antonio; Maggiolini, Marcello

2010-07-15

Fibroblasts are the principal cellular component of connective tissue and are associated with cancer cells at all stages of tumor progression. Structural and functional contributions of fibroblasts to the growth, survival, and invasive capacity of cancer cells are beginning to emerge. In breast carcinoma, approximately 80% of stromal fibroblasts termed cancer-associated fibroblasts (CAF) are thought to manifest an activated phenotype that promotes cancer cell proliferation tumor growth at metastatic sites similar to the primary tumor. In this report, we show that CAFs respond to physiologic concentrations of 17beta-estradiol (E2) by rapidly inducing extracellular signal-regulated kinase phosphorylation and immediate early gene expression, including c-fos and connective tissue growth factor, and cyclin D1. Notably, the E2 response is mediated by the alternate estrogen receptor GPR30, which interfaces with the epidermal growth factor receptor (EGFR) signaling pathway. In particular, E2 stimulates a physical interaction between GPR30 and phosphorylated EGFR, recruiting them to the cyclin D1 gene promoter. Nuclear localization induced by E2 was confirmed by cellular immunofluorescence methods. GPR30 was required for CAF proliferation and migration induced by E2. Our results provide important new mechanistic insights into how CAFs are stimulated by estrogen through a GPR30-mediated nuclear signaling pathway. More generally, they define estrogenic GPR30 signaling as a functionally important component of the tumor microenvironment. (c)2010 AACR.

The Fibroblast Growth Factor signaling pathway

PubMed Central

Ornitz, David M; Itoh, Nobuyuki

2015-01-01

The signaling component of the mammalian Fibroblast Growth Factor (FGF) family is comprised of eighteen secreted proteins that interact with four signaling tyrosine kinase FGF receptors (FGFRs). Interaction of FGF ligands with their signaling receptors is regulated by protein or proteoglycan cofactors and by extracellular binding proteins. Activated FGFRs phosphorylate specific tyrosine residues that mediate interaction with cytosolic adaptor proteins and the RAS-MAPK, PI3K-AKT, PLCγ, and STAT intracellular signaling pathways. Four structurally related intracellular non-signaling FGFs interact with and regulate the family of voltage gated sodium channels. Members of the FGF family function in the earliest stages of embryonic development and during organogenesis to maintain progenitor cells and mediate their growth, differentiation, survival, and patterning. FGFs also have roles in adult tissues where they mediate metabolic functions, tissue repair, and regeneration, often by reactivating developmental signaling pathways. Consistent with the presence of FGFs in almost all tissues and organs, aberrant activity of the pathway is associated with developmental defects that disrupt organogenesis, impair the response to injury, and result in metabolic disorders, and cancer. © 2015 Wiley Periodicals, Inc. PMID:25772309

Toll-like receptor signaling in cell proliferation and survival

PubMed Central

Li, Xinyan; Jiang, Song; Tapping, Richard I.

2009-01-01

Toll-like receptors (TLRs) are important sensors of foreign microbial components as well as products of damaged or inflamed self tissues. Upon sensing these molecules, TLRs initiate a series of downstream signaling events that drive cellular responses including the production of cytokines, chemokines and other inflammatory mediators. This outcome results from the intracellular assembly of protein complexes that drive phosphorylation and other signaling cascades ultimately leading to chromatin remodeling and transcription factor activation. In addition to driving inflammatory responses, TLRs also regulate cell proliferation and survival which serves to expand useful immune cells and integrate inflammatory responses and tissue repair processes. In this context, central TLR signaling molecules, such as the mitogen-activated protein kinases (MAPK) and phosphoinositide 3-kinase (PI3K), play key roles. In addition, four major groups of transcription factors which are targets of TLR activation also control cell fate. This review focuses on the role of TLR signaling as it relates to cell proliferation and survival. This topic not only has important implications for understanding host defense and tissue repair, but also cancer which is often associated with conditions of chronic inflammation. PMID:19775907

Curcumin inhibits TGF-β1-induced connective tissue growth factor expression through the interruption of Smad2 signaling in human gingival fibroblasts.

PubMed

Chen, Jung-Tsu; Wang, Chen-Ying; Chen, Min-Huey

2018-01-13

Many fibrotic processes are associated with an increased level of transforming growth factor-β1 (TGF-β1). TGF-β1 can increase synthesis of matrix proteins and enhance secretion of protease inhibitors, resulting in matrix accumulation. Connective tissue growth factor (CTGF) is a downstream profibrotic effector of TGF-β1 and is associated with the fibrosis in several human organs. Curcumin has been applied to reduce matrix accumulation in fibrotic diseases. This study was aimed to evaluate whether curcumin could suppress TGF-β1-induced CTGF expression and its related signaling pathway involving in this inhibitory action in primary human gingival fibroblasts. The differences in CTGF expression among three types of gingival overgrowth and normal gingival tissues were assessed by immunohistochemistry. Gingival fibroblast viability in cultured media with different concentrations of curcumin was studied by MTT assay. The effect of curcumin on TGF-β1-induced CTGF expression in primary human gingival fibroblasts was examined by immunoblotting. Moreover, the proteins involved in TGF-β1 signaling pathways including TGF-β1 receptors and Smad2 were also analyzed by immunoblotting. CTGF was highly expressed in fibroblasts, epithelial cells and some of endothelial cells, smooth muscle cells, and inflammatory cells in phenytoin-induced gingival overgrowth tissues rather than in those of hereditary and inflammatory gingival overgrowth tissues. Moreover, CTGF expression in the epithelial and connective tissue layers was higher in phenytoin-induced gingival overgrowth tissues than in normal gingival tissues. Curcumin was nontoxic and could reduce TGF-β1-induced CTGF expression by attenuating the phosphorylation and nuclear translocation of Smad2. Curcumin can suppress TGF-β1-induced CTGF expression through the interruption of Smad2 signaling. Copyright © 2018. Published by Elsevier B.V.

Deregulated E2F5/p38/SMAD3 Circuitry Reinforces the Pro-Tumorigenic Switch of TGFβ Signaling in Prostate Cancer.

PubMed

Majumder, Subhadipa; Bhowal, Ankur; Basu, Sanmitra; Mukherjee, Pritha; Chatterji, Urmi; Sengupta, Sanghamitra

2016-11-01

Transforming growth factor-β signaling exerts divergent effects on normal and cancer cells, although mechanism underlying this differential behavior remains unclear. In this study, expression of 94 genes pertaining to the TGF-β signaling pathway was compared between tumor and benign tissue samples from the human prostate gland to identify major discriminators driving prostate carcinogenesis. E2F5 was identified as one of the most deregulated genes in prostate cancer tissues, predominantly in samples with Gleason-score 6. Expression of other deregulated components of TGF-β signaling was examined by qRT-PCR, Western blot, and immune-staining. Function of E2F5 and p38 in prostate cancer was investigated using siRNA-treatment of PC3 cell-line followed by analyses of associated components and cell cycle. Observations revealed that E2F5 overexpression was accompanied by significantly higher phosphorylation of SMAD3 at Ser-208 in the linker region (pSMAD3L) and p38 in tumor tissue. A striking difference in SMAD3 phosphorylation, marked by preponderance of pSMAD3L and pSMAD3C (Ser-423 and 425) in tumor and benign tissues, respectively was noted. Co-localization of E2F5 with pSMAD3L in the nuclei of tumor and PC3 cells indicated a functional interface between the proteins. Downregulation of E2F5 and p38 in PC3 cells resulted in marked reduction of phosphorylation of SMAD3 and perturbation of cell cycle with an arrest of cells in G1 . Our findings unearthed that E2F5/p38 axis played a cardinal role in uncontrolled cellular proliferation in prostate cancer through pSMAD3L activation. It also underscores a strong potential for E2F5 to be incorporated as a tool in early detection of prostate cancer. J. Cell. Physiol. 231: 2482-2492, 2016. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Top-Down Quantitative Proteomics Identified Phosphorylation of Cardiac Troponin I as a Candidate Biomarker for Chronic Heart Failure

PubMed Central

Zhang, Jiang; Guy, Moltu J.; Norman, Holly S.; Chen, Yi-Chen; Xu, Qingge; Dong, Xintong; Guner, Huseyin; Wang, Sijian; Kohmoto, Takushi; Young, Ken H.; Moss, Richard L.; Ge, Ying

2011-01-01

The rapid increase in the prevalence of chronic heart failure (CHF) worldwide underscores an urgent need to identify biomarkers for the early detection of CHF. Post-translational modifications (PTMs) are associated with many critical signaling events during disease progression and thus offer a plethora of candidate biomarkers. We have employed top-down quantitative proteomics methodology for comprehensive assessment of PTMs in whole proteins extracted from normal and diseased tissues. We have systematically analyzed thirty-six clinical human heart tissue samples and identified phosphorylation of cardiac troponin I (cTnI) as a candidate biomarker for CHF. The relative percentages of the total phosphorylated cTnI forms over the entire cTnI populations (%Ptotal) were 56.4±3.5%, 36.9±1.6%, 6.1±2.4%, and 1.0±0.6% for postmortem hearts with normal cardiac function (n=7), early-stage of mild hypertrophy (n=5), severe hypertrophy/dilation (n=4), and end-stage CHF (n=6), respectively. In fresh transplant samples, the %Ptotal of cTnI from non-failing donor (n=4), and end-stage failing hearts (n=10) were 49.5±5.9% and 18.8±2.9%, respectively. Top-down MS with electron capture dissociation unequivocally localized the altered phosphorylation sites to Ser22/23 and determined the order of phosphorylation/dephosphorylation. This study represents the first clinical application of top-down MS-based quantitative proteomics for biomarker discovery from tissues, highlighting the potential of PTM as disease biomarkers. PMID:21751783

Two widely expressed plasma membrane H(+)-ATPase isoforms of Nicotiana tabacum are differentially regulated by phosphorylation of their penultimate threonine.

PubMed

Bobik, Krzysztof; Duby, Geoffrey; Nizet, Yannick; Vandermeeren, Caroline; Stiernet, Patrick; Kanczewska, Justyna; Boutry, Marc

2010-04-01

The plasma membrane H(+)-ATPases PMA2 and PMA4 are the most widely expressed in Nicotiana plumbaginifolia, and belong to two different subfamilies. Both are activated by phosphorylation of a Thr at the penultimate position and the subsequent binding of 14-3-3 proteins. Their expression in Saccharomyces cerevisiae revealed functional and regulatory differences. To determine whether different regulatory properties between PMA2 and PMA4 exist in plants, we generated two monoclonal antibodies able to detect phosphorylation of the penultimate Thr of either PMA2 or PMA4 in a total protein extract. We also raised Nicotiana tabacum transgenic plants expressing 6-His-tagged PMA2 or PMA4, enabling their individual purification. Using these tools we showed that phosphorylation of the penultimate Thr of both PMAs was high during the early exponential growth phase of an N. tabacum cell culture, and then progressively declined. This decline correlated with decreased 14-3-3 binding and decreased plasma membrane ATPase activity. However, the rate and extent of the decrease differed between the two isoforms. Cold stress of culture cells or leaf tissues reduced the Thr phosphorylation of PMA2, whereas no significant changes in Thr phosphorylation of PMA4 were seen. These results strongly suggest that PMA2 and PMA4 are differentially regulated by phosphorylation. Analysis of the H(+)-ATPase phosphorylation status in leaf tissues indicated that no more than 44% (PMA2) or 32% (PMA4) was in the activated state under normal growth conditions. Purification of either isoform showed that, when activated, the two isoforms did not form hetero-oligomers, which is further support for these two H(+)-ATPase subfamilies having different properties.

High intensity interval training improves liver and adipose tissue insulin sensitivity

PubMed Central

Marcinko, Katarina; Sikkema, Sarah R.; Samaan, M. Constantine; Kemp, Bruce E.; Fullerton, Morgan D.; Steinberg, Gregory R.

2015-01-01

Objective Endurance exercise training reduces insulin resistance, adipose tissue inflammation and non-alcoholic fatty liver disease (NAFLD), an effect often associated with modest weight loss. Recent studies have indicated that high-intensity interval training (HIIT) lowers blood glucose in individuals with type 2 diabetes independently of weight loss; however, the organs affected and mechanisms mediating the glucose lowering effects are not known. Intense exercise increases phosphorylation and inhibition of acetyl-CoA carboxylase (ACC) by AMP-activated protein kinase (AMPK) in muscle, adipose tissue and liver. AMPK and ACC are key enzymes regulating fatty acid metabolism, liver fat content, adipose tissue inflammation and insulin sensitivity but the importance of this pathway in regulating insulin sensitivity with HIIT is unknown. Methods In the current study, the effects of 6 weeks of HIIT were examined using obese mice with serine–alanine knock-in mutations on the AMPK phosphorylation sites of ACC1 and ACC2 (AccDKI) or wild-type (WT) controls. Results HIIT lowered blood glucose and increased exercise capacity, food intake, basal activity levels, carbohydrate oxidation and liver and adipose tissue insulin sensitivity in HFD-fed WT and AccDKI mice. These changes occurred independently of weight loss or reductions in adiposity, inflammation and liver lipid content. Conclusions These data indicate that HIIT lowers blood glucose levels by improving adipose and liver insulin sensitivity independently of changes in adiposity, adipose tissue inflammation, liver lipid content or AMPK phosphorylation of ACC. PMID:26909307

Sulforaphane counteracts aggressiveness of pancreatic cancer driven by dysregulated Cx43-mediated gap junctional intercellular communication

PubMed Central

Zhang, Yiyao; Isayev, Orkhan; Heilmann, Katharina; Schoensiegel, Frank; Liu, Li; Nessling, Michelle; Richter, Karsten; Labsch, Sabrina; Nwaeburu, Clifford C.; Mattern, Juergen; Gladkich, Jury; Giese, Nathalia; Werner, Jens; Schemmer, Peter; Gross, Wolfgang; Gebhard, Martha M.; Gerhauser, Clarissa; Schaefer, Michael; Herr, Ingrid

2014-01-01

The extreme aggressiveness of pancreatic ductal adenocarcinoma (PDA) has been associated with blocked gap junctional intercellular communication (GJIC) and the presence of cancer stem cells (CSCs). We examined whether disturbed GJIC is responsible for a CSC phenotype in established and primary cancer cells and patient tissue of PDA using interdisciplinary methods based in physiology, cell and molecular biology, histology and epigenetics. Flux of fluorescent dyes and gemcitabine through gap junctions (GJs) was intact in less aggressive cells but not in highly malignant cells with morphological dysfunctional GJs. Among several connexins, only Cx43 was expressed on the cell surface of less aggressive and GJIC-competent cells, whereas Cx43 surface expression was absent in highly malignant, E-cadherin-negative and GJIC-incompetent cells. The levels of total Cx43 protein and Cx43 phosphorylated at Ser368 and Ser279/282 were high in normal tissue but low to absent in malignant tissue. si-RNA-mediated inhibition of Cx43 expression in GJIC-competent cells prevented GJIC and induced colony formation and the expression of stem cell-related factors. The bioactive substance sulforaphane enhanced Cx43 and E-cadherin levels, inhibited the CSC markers c-Met and CD133, improved the functional morphology of GJs and enhanced GJIC. Sulforaphane altered the phosphorylation of several kinases and their substrates and inhibition of GSK3, JNK and PKC prevented sulforaphane-induced CX43 expression. The sulforaphane-mediated expression of Cx43 was not correlated with enhanced Cx43 RNA expression, acetylated histone binding and Cx43 promoter de-methylation, suggesting that posttranslational phosphorylation is the dominant regulatory mechanism. Together, the absence of Cx43 prevents GJIC and enhances aggressiveness, whereas sulforaphane counteracts this process, and our findings highlight dietary co-treatment as a viable treatment option for PDA. PMID:24742583

Fisetin, a dietary flavonoid, ameliorates experimental colitis in mice: Relevance of NF-κB signaling.

PubMed

Sahu, Bidya Dhar; Kumar, Jerald Mahesh; Sistla, Ramakrishna

2016-02-01

Fisetin, a dietary flavonoid, is commonly found in many fruits and vegetables. Although studies indicate that fisetin has an anti-inflammatory property, little is known about its effects on intestinal inflammation. The present study investigated the effects of the fisetin on dextran sulphate sodium (DSS)-induced murine colitis, an animal model that resembles human inflammatory bowel disease. Fisetin treatment to DSS-exposed mice significantly reduced the severity of colitis and alleviated the macroscopic and microscopic signs of the disease. Moreover, fisetin reduced the levels of myeloperoxidase activity, the production of proinflammatory cytokines, tumor necrosis factor-alpha (TNF-α), interleukin-1 beta (IL-1β) and interleukin-6 (IL-6) and the expressions of COX-2 and iNOS in the colon tissues. Further studies revealed that fisetin suppressed the activation of NF-κB (p65) by inhibiting IκBα phosphorylation and NF-κB (p65)-DNA binding activity and attenuated the phosphorylation of Akt and the p38, but not ERK and JNK MAPKs in the colon tissues of DSS-exposed mice. In addition, DSS-induced decline in reduced glutathione (GSH) and the increase in malondialdehyde (MDA) levels were significantly restored by oral fisetin. Furthermore, the results from in vitro studies showed that fisetin significantly reduced the pro-inflammatory cytokine and mediator release and suppressed the degradation and phosphorylation of IκBα with subsequent nuclear translocation of NF-κB (p65) in lipopolysaccharide (LPS)-stimulated mouse primary peritoneal macrophages. These results suggest that fisetin exerts anti-inflammatory activity via inhibition of Akt, p38 MAPK and NF-κB signaling in the colon tissues of DSS-exposed mice. Thus, fisetin may be a promising candidate as pharmaceuticals or nutraceuticals in the treatment of inflammatory bowel disease. Copyright © 2015 Elsevier Inc. All rights reserved.

Sulforaphane counteracts aggressiveness of pancreatic cancer driven by dysregulated Cx43-mediated gap junctional intercellular communication.

PubMed

Forster, Tobias; Rausch, Vanessa; Zhang, Yiyao; Isayev, Orkhan; Heilmann, Katharina; Schoensiegel, Frank; Liu, Li; Nessling, Michelle; Richter, Karsten; Labsch, Sabrina; Nwaeburu, Clifford C; Mattern, Juergen; Gladkich, Jury; Giese, Nathalia; Werner, Jens; Schemmer, Peter; Gross, Wolfgang; Gebhard, Martha M; Gerhauser, Clarissa; Schaefer, Michael; Herr, Ingrid

2014-03-30

The extreme aggressiveness of pancreatic ductal adenocarcinoma (PDA) has been associated with blocked gap junctional intercellular communication (GJIC) and the presence of cancer stem cells (CSCs). We examined whether disturbed GJIC is responsible for a CSC phenotype in established and primary cancer cells and patient tissue of PDA using interdisciplinary methods based in physiology, cell and molecular biology, histology and epigenetics. Flux of fluorescent dyes and gemcitabine through gap junctions (GJs) was intact in less aggressive cells but not in highly malignant cells with morphological dysfunctional GJs. Among several connexins, only Cx43 was expressed on the cell surface of less aggressive and GJIC-competent cells, whereas Cx43 surface expression was absent in highly malignant, E-cadherin-negative and GJIC-incompetent cells. The levels of total Cx43 protein and Cx43 phosphorylated at Ser368 and Ser279/282 were high in normal tissue but low to absent in malignant tissue. si-RNA-mediated inhibition of Cx43 expression in GJIC-competent cells prevented GJIC and induced colony formation and the expression of stem cell-related factors. The bioactive substance sulforaphane enhanced Cx43 and E-cadherin levels, inhibited the CSC markers c-Met and CD133, improved the functional morphology of GJs and enhanced GJIC. Sulforaphane altered the phosphorylation of several kinases and their substrates and inhibition of GSK3, JNK and PKC prevented sulforaphane-induced CX43 expression. The sulforaphane-mediated expression of Cx43 was not correlated with enhanced Cx43 RNA expression, acetylated histone binding and Cx43 promoter de-methylation, suggesting that posttranslational phosphorylation is the dominant regulatory mechanism. Together, the absence of Cx43 prevents GJIC and enhances aggressiveness, whereas sulforaphane counteracts this process, and our findings highlight dietary co-treatment as a viable treatment option for PDA.

Insulin/IGF and sex hormone axes in human endometrium and associations with endometrial cancer risk factors.

PubMed

Merritt, Melissa A; Strickler, Howard D; Einstein, Mark H; Yang, Hannah P; Sherman, Mark E; Wentzensen, Nicolas; Brouwer-Visser, Jurriaan; Cossio, Maria Jose; Whitney, Kathleen D; Yu, Herbert; Gunter, Marc J; Huang, Gloria S

2016-06-01

Experimental and observational data link insulin, insulin-like growth factor (IGF), and estrogens to endometrial tumorigenesis. However, there are limited data regarding insulin/IGF and sex hormone axes protein and gene expression in normal endometrial tissues, and very few studies have examined the impact of endometrial cancer risk factors on endometrial tissue biology. We evaluated endometrial tissues from 77 premenopausal and 30 postmenopausal women who underwent hysterectomy for benign indications and had provided epidemiological data. Endometrial tissue mRNA and protein levels were measured using quantitative real-time PCR and immunohistochemistry, respectively. In postmenopausal women, we observed higher levels of phosphorylated IGF-I/insulin receptor (pIGF1R/pIR) in diabetic versus non-diabetic women (p value =0.02), while women who reported regular nonsteroidal anti-inflammatory drug use versus no use had higher levels of insulin and progesterone receptors (both p values ≤0.03). We also noted differences in pIGF1R/pIR staining with OC use (postmenopausal women only), and the proportion of estrogen receptor-positive tissues varied by the number of live births and PTEN status (premenopausal only) (p values ≤0.04). Compared to premenopausal proliferative phase women, postmenopausal women exhibited lower mRNA levels of IGF1, but higher IGFBP1 and IGFBP3 expression (all p values ≤0.004), and higher protein levels of the receptors for estrogen, insulin, and IGF-I (all p values ≤0.02). Conversely, pIGF1R/pIR levels were higher in premenopausal proliferative phase versus postmenopausal endometrium (p value =0.01). These results highlight links between endometrial cancer risk factors and mechanistic factors that may contribute to early events in the multistage process of endometrial carcinogenesis.

Smad2 and Smad3 phosphorylated at both linker and COOH-terminal regions transmit malignant TGF-beta signal in later stages of human colorectal cancer.

PubMed

Matsuzaki, Koichi; Kitano, Chiaki; Murata, Miki; Sekimoto, Go; Yoshida, Katsunori; Uemura, Yoshiko; Seki, Toshihito; Taketani, Shigeru; Fujisawa, Jun-ichi; Okazaki, Kazuichi

2009-07-01

Transforming growth factor (TGF)-beta initially inhibits growth of mature epithelial cells. Later, however, autocrine TGF-beta signaling acts in concert with the Ras pathway to induce a proliferative and invasive phenotype. TGF-beta activates not only TGF-beta type I receptor (TbetaRI) but also Ras-associated kinases, which differentially phosphorylate the mediators Smad2 and Smad3 to create distinct phosphorylated forms: COOH-terminally phosphorylated Smad2/3 (pSmad2C and pSmad3C) and both linker and COOH-terminally phosphorylated Smad2/3 (pSmad2L/C and pSmad3L/C). In this study, we investigated actions of pSmad2L/C and pSmad3L/C in cancer progression. TGF-beta inhibited cell growth by down-regulating c-Myc oncoprotein through the pSmad2C and pSmad3C pathway; TGF-beta signaling, in turn, enhanced cell growth by up-regulating c-Myc through the cyclin-dependent kinase (CDK) 4-dependent pSmad2L/C and pSmad3L/C pathways in cell nuclei. Alternatively, TbetaRI and c-Jun NH2-terminal kinase (JNK) together created cytoplasmic pSmad2L/C, which entered the nucleus and stimulated cell invasion, partly by up-regulating matrix metalloproteinase-9. In 20 clinical samples, pSmad2L/C and pSmad3L/C showed nuclear localization at invasion fronts of all TGF-beta-producing human metastatic colorectal cancers. In vitro kinase assay confirmed that nuclear CDK4 and cytoplasmic JNK obtained from the tumor tissue could phosphorylate Smad2 or Smad3 at their linker regions. We suggest that CDK4, together with JNK, alters tumor-suppressive TGF-beta signaling to malignant characteristics in later stages of human colorectal cancer. The linker phosphorylation of Smad2 and Smad3 may represent a target for intervention in human metastatic cancer.

Differential regulation of the transcriptional activity of the glucocorticoid receptor through site-specific phosphorylation.

PubMed

Kumar, Raj; Calhoun, William J

2008-12-01

Post-translational modifications such as phosphorylation are known to play an important role in the gene regulation by the transcription factors including the nuclear hormone receptor superfamily of which the glucocorticoid receptor (GR) is a member. Protein phosphorylation often switches cellular activity from one state to another. Like many other transcription factors, the GR is a phosphoprotein, and phosphorylation plays an important role in the regulation of GR activity. Cell signaling pathways that regulate phosphorylation of the GR and its associated proteins are important determinants of GR function under various physiological conditions. While the role of many phosphorylation sites in the GR is still not fully understood, the role of others is clearer. Several aspects of transcription factor function, including DNA binding affinity, interaction of transactivation domains with the transcription initiation complex, and shuttling between the cytoplasmic compartments, have all been linked to site-specific phosphorylation. All major phosphorylation sites in the human GR are located in the N-terminal domain including the major transactivation domain, AF1. Available literature clearly indicates that many of these potential phosphorylation sites are substrates for multiple kinases, suggesting the potential for a very complex regulatory network. Phosphorylated GR interacts favorably with critical coregulatory proteins and subsequently enhances transcriptional activity. In addition, the activities and specificities of coregulators may be subject to similar regulation by phosphorylation. Regulation of the GR activity due to phosphorylation appears to be site-specific and dependent upon specific cell signaling cascade. Taken together, site-specific phosphorylation and related kinase pathways play an important role in the action of the GR, and more precise mechanistic information will lead to fuller understanding of the complex nature of gene regulation by the GR- and related transcription factors. This review provides currently available information regarding the role of GR phosphorylation in its action, and highlights the possible underlying mechanisms of action.

Signal transduction through the IL-4 and insulin receptor families.

PubMed

Wang, L M; Keegan, A; Frankel, M; Paul, W E; Pierce, J H

1995-07-01

Activation of tyrosine kinase-containing receptors and intracellular tyrosine kinases by ligand stimulation is known to be crucial for mediating initial and subsequent events involved in mitogenic signal transduction. Receptors for insulin and insulin-like growth factor 1 (IGF-1) contain cytoplasmic tyrosine kinase domains that undergo autophosphorylation upon ligand stimulation. Activation of these receptors also leads to pronounced and rapid tyrosine phosphorylation of insulin receptor substrate 1 (IRS-1) in cells of connective tissue origin. A related substrate, designated 4PS, is similarly phosphorylated by insulin and IGF-1 stimulation in many hematopoietic cell types. IRS-1 and 4PS possess a number of tyrosine phosphorylation sites that are within motifs that bind specific SH2-containing molecules known to be involved in mitogenic signaling such as PI-3 kinase, SHPTP-2 (Syp) and Grb-2. Thus, they appear to act as docking substrates for a variety of signaling molecules. The majority of hematopoietic cytokines bind to receptors that do not possess intrinsic kinase activity, and these receptors have been collectively termed as members of the hematopoietin receptor superfamily. Despite their lack of tyrosine kinase domains, stimulation of these receptors has been demonstrated to activate intracellular kinases leading to tyrosine phosphorylation of multiple substrates. Recent evidence has demonstrated that activation of different members of the Janus family of tyrosine kinases is involved in mediating tyrosine phosphorylation events by specific cytokines. Stimulation of the interleukin 4 (IL-4) receptor, a member of the hematopoietin receptor superfamily, is thought to result in activation of Jak1, Jak3, and/or Fes tyrosine kinases.(ABSTRACT TRUNCATED AT 250 WORDS)

[Molecular markers of Alzheimer disease early diagnostic: investigation perspectives of peripheral tissues.

PubMed

Paltsev, M A; Zuev, V A; Kozhevnikova, E O; Linkova, N S; Kvetnaia, T V; Polyakova, V O; Kvetnoy, I M

2017-01-01

Alzheimer's disease (AD) is a progressive neurodegenerative disorder of elderly and old age people. For intravital diagnosis of the expression of signaling molecules - AD markers, cerebrospinal fluid (CSF) and peripheral tissues are used: lymphocytes and blood platelets, buccal and olfactory epithelium, skin fibroblasts. There are several changes in the production of hyper phosphorylated form of τ-protein, BACE1 and peptide Аβ42 in CSF in case of AD, but CSF taking may have a number of side effects. Less traumatic taking of sampling tissues for the diagnosis of AD is in use of epithelium biopsy and blood portion. An increase in the expression of the hyper phosphorylated form of τ-protein is shown in blood lymphocytes of AD patients. An increase in the content of high molecular weight forms of phosphorylated t-protein and amyloid precursor protein-APP was also revealed in blood platelets of AD patients. Changes in the amount of 2 miRNA families - miR-132 family and miR-134 family were revealed in blood cells 1-5 years before the manifestation of clinical signs of AD. An increase in the concentration of bound calcium, synthesis of peptides Aβ40 and Aβ42, τ protein was observed in AD skin fibroblasts. In the olfactory and buccal epithelium an increase in the expression of hyper phosphorylated form of τ-protein and Aβ peptide was detected in patients with AD. Verification of AD markers in peripheral tissues for biopsy have the important significant for life diagnostics, prevention and and target AD treatment.

The Impact of Small RNA Interference Against Homer1 on Rats with Type 2 Diabetes and ERK Phosphorylation.

PubMed

Lu, Jun; Gan, Jihong; Fu, Guoqiang; Ding, Lu; Zheng, Qiangsun

2015-12-01

The objective of the study is to evaluate Homer1 expression in rats with Type 2 diabetes mellitus (T2DM) and investigate the mechanism by which Homer1 influences the pathogenesis of diabetes through study on rat model with decreased Homer1 expression. Rat model of T2DM was constructed and blood insulin concentration was measured. Homer1 mRNA and protein expressions in rat pancreatic tissue were determined using RT-PCR as well as Western blotting. Homer1 expression in human monocytic THP-1 cells was interfered using short hairpin RNA, and its effect on phosphorylation of extracellular signal-regulated kinase (ERK) was assessed. Fasting glucose concentration in rat model of T2DM was significantly higher than that of normal rats (13.1 ± 2.4 vs 5.1 ± 1.1 mmol/L), and fasting blood insulin concentration of diabetic group was significantly lower than that of normal group (13.6 ± 1.9 18.3 ± 2.2 mIU/L) (P < 0.05). Homer1 mRNA and protein expressions in pancreatic tissue of rats with T2DM were significantly higher than those of normal rats (P < 0.05). Level of ERK phosphorylation in pancreatic tissue of rats with T2DM was significantly higher than that of normal rats. Homer1 mRNA level in rat pancreatic tissue of T2DM was positively correlated with the area of pancreatic islets (r = 0.526, P = 0.014). Homer1 mRNA level was significantly inhibited in high-glucose and high-fat stimulated human monotypic THP-1 cells with interfered Homer1. Compared with controls, P-ERK phosphorylation was significantly decreased in THP-1 cells with interfered Homer1 (P < 0.05). Homer1 can promote the progression of T2DM, which may be achieved through affecting ERK phosphorylation.

A Missense Mutation in PPP1R15B Causes a Syndrome Including Diabetes, Short Stature, and Microcephaly

PubMed Central

Abdulkarim, Baroj; Igoillo-Esteve, Mariana; Daures, Mathilde; Romero, Sophie; Philippi, Anne; Senée, Valérie; Lopes, Miguel; Cunha, Daniel A.; Harding, Heather P.; Derbois, Céline; Bendelac, Nathalie; Hattersley, Andrew T.; Eizirik, Décio L.; Ron, David

2015-01-01

Dysregulated endoplasmic reticulum stress and phosphorylation of eukaryotic translation initiation factor 2α (eIF2α) are associated with pancreatic β-cell failure and diabetes. Here, we report the first homozygous mutation in the PPP1R15B gene (also known as constitutive repressor of eIF2α phosphorylation [CReP]) encoding the regulatory subunit of an eIF2α-specific phosphatase in two siblings affected by a novel syndrome of diabetes of youth with short stature, intellectual disability, and microcephaly. The R658C mutation in PPP1R15B affects a conserved amino acid within the domain important for protein phosphatase 1 (PP1) binding. The R658C mutation decreases PP1 binding and eIF2α dephosphorylation and results in β-cell apoptosis. Our findings support the concept that dysregulated eIF2α phosphorylation, whether decreased by mutation of the kinase (EIF2AK3) in Wolcott-Rallison syndrome or increased by mutation of the phosphatase (PPP1R15B), is deleterious to β-cells and other secretory tissues, resulting in diabetes associated with multisystem abnormalities. PMID:26159176

Human Umbilical Cord Mesenchymal Stem Cells Reduce Fibrosis of Bleomycin-Induced Lung Injury

PubMed Central

Moodley, Yuben; Atienza, Daniel; Manuelpillai, Ursula; Samuel, Chrishan S.; Tchongue, Jorge; Ilancheran, Sivakami; Boyd, Richard; Trounson, Alan

2009-01-01

Acute respiratory distress syndrome is characterized by loss of lung tissue as a result of inflammation and fibrosis. Augmenting tissue repair by the use of mesenchymal stem cells may be an important advance in treating this condition. We evaluated the role of term human umbilical cord cells derived from Wharton’s jelly with a phenotype consistent with mesenchymal stem cells (uMSCs) in the treatment of a bleomycin-induced mouse model of lung injury. uMSCs were administered systemically, and lungs were harvested at 7, 14, and 28 days post-bleomycin. Injected uMSCs were located in the lung 2 weeks later only in areas of inflammation and fibrosis but not in healthy lung tissue. The administration of uMSCs reduced inflammation and inhibited the expression of transforming growth factor-β, interferon-γ, and the proinflammatory cytokines macrophage migratory inhibitory factor and tumor necrosis factor-α. Collagen concentration in the lung was significantly reduced by uMSC treatment, which may have been a consequence of the simultaneous reduction in Smad2 phosphorylation (transforming growth factor-β activity). uMSCs also increased matrix metalloproteinase-2 levels and reduced their endogenous inhibitors, tissue inhibitors of matrix metalloproteinases, favoring a pro-degradative milieu following collagen deposition. Notably, injected human lung fibroblasts did not influence either collagen or matrix metalloproteinase levels in the lung. The results of this study suggest that uMSCs have antifibrotic properties and may augment lung repair if used to treat acute respiratory distress syndrome. PMID:19497992

Key role of integrin α(IIb)β (3) signaling to Syk kinase in tissue factor-induced thrombin generation.

PubMed

van der Meijden, Paola E J; Feijge, Marion A H; Swieringa, Frauke; Gilio, Karen; Nergiz-Unal, Reyhan; Hamulyák, Karly; Heemskerk, Johan W M

2012-10-01

The fibrin(ogen) receptor, integrin α(IIb)β(3), has a well-established role in platelet spreading, aggregation and clot retraction. How α(IIb)β(3) contributes to platelet-dependent coagulation is less well resolved. Here, we demonstrate that the potent suppressing effect of clinically used α(IIb)β(3) blockers on tissue factor-induced thrombin generation is linked to diminished platelet Ca(2+) responses and phosphatidylserine (PS) exposure. The same blockers suppress these responses in platelets stimulated with collagen and thrombin receptor agonists, whereas added fibrinogen potentiates these responses. In platelets spreading on fibrinogen, outside-in α(IIb)β(3) signaling similarly enhances thrombin-induced Ca(2+) rises and PS exposure. These responses are reduced in α(IIb)β(3)-deficient platelets from patients with Glanzmann's thrombasthenia. Furthermore, the contribution of α(IIb)β(3) to tissue factor-induced platelet Ca(2+) rises, PS exposure and thrombin generation in plasma are fully dependent on Syk kinase activity. Tyrosine phosphorylation analysis confirms a key role of Syk activation, which is largely but not exclusively dependent on α(IIb)β(3) activation. It is concluded that the majority of tissue factor-induced procoagulant activity of platelets relies on Syk activation and ensuing Ca(2+) signal generation, and furthermore that a considerable part of Syk activation relies on α(IIb)β(3) signaling. These results hence point to a novel role of Syk in integrin-dependent thrombin generation.

Roles of cell-cell adhesion-dependent tyrosine phosphorylation of Gab-1.

PubMed

Shinohara, M; Kodama, A; Matozaki, T; Fukuhara, A; Tachibana, K; Nakanishi, H; Takai, Y

2001-06-01

Gab-1 is a multiple docking protein that is tyrosine phosphorylated by receptor tyrosine kinases such as c-Met, hepatocyte growth factor/scatter factor receptor, and epidermal growth factor receptor. We have now demonstrated that cell-cell adhesion also induces marked tyrosine phosphorylation of Gab-1 and that disruption of cell-cell adhesion results in its dephosphorylation. An anti-E-cadherin antibody decreased cell-cell adhesion-dependent tyrosine phosphorylation of Gab-1, whereas the expression of E-cadherin specifically induced tyrosine phosphorylation of Gab-1. A relatively selective inhibitor of Src family kinases reduced cell-cell adhesion-dependent tyrosine phosphorylation of Gab-1, whereas expression of a dominant-negative mutant of Csk increased it. Disruption of cell-cell adhesion, which reduced tyrosine phosphorylation of Gab-1, also reduced the activation of mitogen-activated protein kinase and Akt in response to cell-cell adhesion. These results indicate that E-cadherin-mediated cell-cell adhesion induces tyrosine phosphorylation by a Src family kinase of Gab-1, thereby regulating the activation of Ras/MAP kinase and phosphatidylinositol 3-kinase/Akt cascades.

Posttranslationally modified progesterone receptors direct ligand-specific expression of breast cancer stem cell-associated gene programs.

PubMed

Knutson, Todd P; Truong, Thu H; Ma, Shihong; Brady, Nicholas J; Sullivan, Megan E; Raj, Ganesh; Schwertfeger, Kathryn L; Lange, Carol A

2017-04-17

Estrogen and progesterone are potent breast mitogens. In addition to steroid hormones, multiple signaling pathways input to estrogen receptor (ER) and progesterone receptor (PR) actions via posttranslational events. Protein kinases commonly activated in breast cancers phosphorylate steroid hormone receptors (SRs) and profoundly impact their activities. To better understand the role of modified PRs in breast cancer, we measured total and phospho-Ser294 PRs in 209 human breast tumors represented on 2754 individual tissue spots within a tissue microarray and assayed the regulation of this site in human tumor explants cultured ex vivo. To complement this analysis, we assayed PR target gene regulation in T47D luminal breast cancer models following treatment with progestin (promegestone; R5020) and antiprogestins (mifepristone, onapristone, or aglepristone) in conditions under which the receptor is regulated by Lys388 SUMOylation (K388 intact) or is SUMO-deficient (via K388R mutation to mimic persistent Ser294 phosphorylation). Selected phospho-PR-driven target genes were validated by qRT-PCR and following RUNX2 shRNA knockdown in breast cancer cell lines. Primary and secondary mammosphere assays were performed to implicate phospho-Ser294 PRs, epidermal growth factor signaling, and RUNX2 in breast cancer stem cell biology. Phospho-Ser294 PR species were abundant in a majority (54%) of luminal breast tumors, and PR promoter selectivity was exquisitely sensitive to posttranslational modifications. Phospho-PR expression and target gene programs were significantly associated with invasive lobular carcinoma (ILC). Consistent with our finding that activated phospho-PRs undergo rapid ligand-dependent turnover, unique phospho-PR gene signatures were most prevalent in breast tumors clinically designated as PR-low to PR-null (luminal B) and included gene sets associated with cancer stem cell biology (HER2, PAX2, AHR, AR, RUNX). Validation studies demonstrated a requirement for RUNX2 in the regulation of selected phospho-PR target genes (SLC37A2). In vitro mammosphere formation assays support a role for phospho-Ser294-PRs via growth factor (EGF) signaling as well as RUNX2 as potent drivers of breast cancer stem cell fate. We conclude that PR Ser294 phosphorylation is a common event in breast cancer progression that is required to maintain breast cancer stem cell fate, in part via cooperation with growth factor-initiated signaling pathways and key phospho-PR target genes including SLC37A2 and RUNX2. Clinical measurement of phosphorylated PRs should be considered a useful marker of breast tumor stem cell potential. Alternatively, unique phospho-PR target gene sets may provide useful tools with which to identify patients likely to respond to selective PR modulators that block PR Ser294 phosphorylation as part of rational combination (i.e., with antiestrogens) endocrine therapies designed to durably block breast cancer recurrence.

Nrf2 reduces levels of phosphorylated tau protein by inducing autophagy adaptor protein NDP52

NASA Astrophysics Data System (ADS)

Jo, Chulman; Gundemir, Soner; Pritchard, Susanne; Jin, Youngnam N.; Rahman, Irfan; Johnson, Gail V. W.

2014-03-01

Nuclear factor erythroid 2-related factor 2 (Nrf2) is a pivotal transcription factor in the defence against oxidative stress. Here we provide evidence that activation of the Nrf2 pathway reduces the levels of phosphorylated tau by induction of an autophagy adaptor protein NDP52 (also known as CALCOCO2) in neurons. The expression of NDP52, which we show has three antioxidant response elements (AREs) in its promoter region, is strongly induced by Nrf2, and its overexpression facilitates clearance of phosphorylated tau in the presence of an autophagy stimulator. In Nrf2-knockout mice, phosphorylated and sarkosyl-insoluble tau accumulates in the brains concurrent with decreased levels of NDP52. Moreover, NDP52 associates with phosphorylated tau from brain cortical samples of Alzheimer disease cases, and the amount of phosphorylated tau in sarkosyl-insoluble fractions is inversely proportional to that of NDP52. These results suggest that NDP52 plays a key role in autophagy-mediated degradation of phosphorylated tau in vivo.

soc-2 encodes a leucine-rich repeat protein implicated in fibroblast growth factor receptor signaling

PubMed Central

Selfors, Laura M.; Schutzman, Jennifer L.; Borland, Christina Z.; Stern, Michael J.

1998-01-01

Activation of fibroblast growth factor (FGF) receptors elicits diverse cellular responses including growth, mitogenesis, migration, and differentiation. The intracellular signaling pathways that mediate these important processes are not well understood. In Caenorhabditis elegans, suppressors of clr-1 identify genes, termed soc genes, that potentially mediate or activate signaling through the EGL-15 FGF receptor. We demonstrate that three soc genes, soc-1, soc-2, and sem-5, suppress the activity of an activated form of the EGL-15 FGF receptor, consistent with the soc genes functioning downstream of EGL-15. We show that soc-2 encodes a protein composed almost entirely of leucine-rich repeats, a domain implicated in protein–protein interactions. We identified a putative human homolog, SHOC-2, which is 54% identical to SOC-2. We find that shoc-2 maps to 10q25, shoc-2 mRNA is expressed in all tissues assayed, and SHOC-2 protein is cytoplasmically localized. Within the leucine-rich repeats of both SOC-2 and SHOC-2 are two YXNX motifs that are potential tyrosine-phosphorylated docking sites for the SEM-5/GRB2 Src homology 2 domain. However, phosphorylation of these residues is not required for SOC-2 function in vivo, and SHOC-2 is not observed to be tyrosine phosphorylated in response to FGF stimulation. We conclude that this genetic system has allowed for the identification of a conserved gene implicated in mediating FGF receptor signaling in C. elegans. PMID:9618511

Phosphorylation at tyrosine 114 of Proliferating Cell Nuclear Antigen (PCNA) is required for adipogenesis in response to high fat diet

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lo, Yuan-Hung; Ho, Po-Chun; Chen, Min-Shan

Highlights: Black-Right-Pointing-Pointer Proliferating Cell Nuclear Antigen (PCNA) is phosphorylated at Y114. Black-Right-Pointing-Pointer Phospho-Y114 of PCNA is not required for cell proliferation for normal growth. Black-Right-Pointing-Pointer MCE during adipogenesis is abolished in the lack of the phosphorylation. Black-Right-Pointing-Pointer Homozygous Y114F mice are resistant to high fat diet induced obesity. Black-Right-Pointing-Pointer Our results shed light on the interface between proliferation and differentiation. -- Abstract: Clonal proliferation is an obligatory component of adipogenesis. Although several cell cycle regulators are known to participate in the transition between pre-adipocyte proliferation and terminal adipocyte differentiation, how the core DNA synthesis machinery is coordinately regulated in adipogenesismore » remains elusive. PCNA (Proliferating Cell Nuclear Antigen) is an indispensable component for DNA synthesis during proliferation. Here we show that PCNA is subject to phosphorylation at the highly conserved tyrosine residue 114 (Y114). Replacing the Y114 residue with phenylalanine (Y114F), which is structurally similar to tyrosine but cannot be phosphorylated, does not affect normal animal development. However, when challenged with high fat diet, mice carrying homozygous Y114F alleles (PCNA{sup F/F}) are resistant to adipose tissue enlargement in comparison to wild-type (WT) mice. Mouse embryonic fibroblasts (MEFs) harboring WT or Y114F mutant PCNA proliferate at similar rates. However, when subjected to adipogenesis induction in culture, PCNA{sup F/F} MEFs are not able to re-enter the cell cycle and fail to form mature adipocytes, while WT MEFs undergo mitotic clonal expansion in response to the adipogenic stimulation, accompanied by enhanced Y114 phosphorylation of PCNA, and differentiate to mature adipocytes. Consistent with the function of Y114 phosphorylation in clonal proliferation in adipogenesis, fat tissues isolated from WT mice contain significantly more adipocytes than those isolated from PCNA{sup F/F} mice. This study identifies a critical role for PCNA in adipose tissue development, and for the first time identifies a role of the core DNA replication machinery at the interface between proliferation and differentiation.« less

[Coactivators in energy metabolism: peroxisome proliferator-activated receptor-gamma coactivator 1 family].

PubMed

Wang, Rui; Chang, Yong-sheng; Fang, Fu-de

2009-12-01

Peroxisome proliferator-activated receptor gamma coactivator 1 (PGC1) family is highly expressed in tissues with high energy metabolism. They coactivate transcription factors in regulating genes engaged in processes such as gluconeogenesis, adipose beta-oxydation, lipoprotein synthesis and secretion, mitochondrial biogenesis, and oxidative metabolism. Protein conformation studies demonstrated that they lack DNA binding domains and act as coactivators through physical interaction with transcription factors. PGC1 activity is regulated at transcription level or by multiple covalent chemical modifications such as phosphorylation, methylation and acetylation/deacetylation. Abnormal expression of PGC1 coactivators usually is closely correlated with diseases such as diabetes, obesity, hyperglycemia, hyperlipemia, and arterial and brain neuron necrosis diseases.

In vivo phosphorylation of WRKY transcription factor by MAPK.

PubMed

Ishihama, Nobuaki; Adachi, Hiroaki; Yoshioka, Miki; Yoshioka, Hirofumi

2014-01-01

Plants activate signaling networks in response to diverse pathogen-derived signals, facilitating transcriptional reprogramming through mitogen-activated protein kinase (MAPK) cascades. Identification of phosphorylation targets of MAPK and in vivo detection of the phosphorylated substrates are important processes to elucidate the signaling pathway in plant immune responses. We have identified a WRKY transcription factor, which is phosphorylated by defense-related MAPKs, SIPK and WIPK. Recent evidence demonstrated that some group I WRKY transcription factors, which contain a conserved motif in the N-terminal region, are activated by MAPK-dependent phosphorylation. In this chapter, we describe protocols for preparation of anti-phosphopeptide antibodies, detection of activated MAPKs using anti-phospho-MAPK antibody, and activated WRKY using anti-phospho-WRKY antibody, respectively.

DIRECT MODULATION OF THE PROTEIN KINASE A CATALYTIC SUBUNIT α BY GROWTH FACTOR RECEPTOR TYROSINE KINASES

PubMed Central

Caldwell, George B.; Howe, Alan K.; Nickl, Christian K.; Dostmann, Wolfgang R.; Ballif, Bryan A.; Deming, Paula B.

2011-01-01

The cyclic-AMP-dependent protein kinase A (PKA) regulates processes such as cell proliferation and migration following activation of growth factor receptor tyrosine kinases (RTKs), yet the signaling mechanisms that link PKA with growth factor receptors remain largely undefined. Here we report that RTKs can directly modulate the function of the catalytic subunit of PKA (PKA-C) through post-translational modification. In vitro kinase assays revealed that both the epidermal growth factor and platelet derived growth factor receptors (EGFR and PDGFR, respectively) tyrosine phosphorylate PKA-C. Mass spectrometry identified tyrosine 330 (Y330) as a receptor-mediated phosphorylation site and mutation of Y330 to phenylalanine (Y330F) all but abolished the RTK-mediated phosphorylation of PKA-C in vitro. Y330 resides within a conserved region at the C-terminal tail of PKA-C that allosterically regulates enzymatic activity. Therefore, the effect of phosphorylation at Y330 on the activity of PKA-C was investigated. The Km for a peptide substrate was markedly decreased when PKA-C subunits were tyrosine phosphorylated by the receptors as compared to un-phosphorylated controls. Importantly, tyrosine-phosphorylated PKA-C subunits were detected in cells stimulated with EGF, PDGF and FGF2 and in fibroblasts undergoing PDGF-mediated chemotaxis. These results demonstrate a direct, functional interaction between RTKs and PKA-C and identify tyrosine phosphorylation as a novel mechansim for regulating PKA activity. PMID:21866565

Identification of a Kinase in Wheat Germ that Phosphorylates the Large Subunit of Initiation Factor 4F 1

PubMed Central

Humphreys, Jean; Browning, Karen S.; Ravel, Joanne M.

1988-01-01

A kinase has been isolated from wheat (Triticum aestivum) germ that phosphorylates the 220 kilodaltons (kD) subunit of wheat germ initiation factor (eIF) 4F, the 80 kD subunit of eIF-4B (an isozyme form of eIF-4F) and eIF-4G (the functional equivalent to mammalian eIF-4B). The kinase elutes from Sephacryl S-200 slightly in front of ovalbumin. The kinase phosphorylates casein and histone IIA to a small extent, but does not phosphorylate phosvitin. Of the wheat germ initiation factors, elongation factors, and small and large ribosomal subunits, only eIF-4F, eIF-4B, and eIF-4G are phosphorylated to a significant extent. The kinase phosphorylates eIF-4F to the extent of two phosphates per mole of the 220 kD subunit and phosphorylates eIF-4B to the extent of one phosphate per mole of the 80 kD subunit. The 26 kD subunit of eIF-4F and the 28 kD subunit of eIF-4B are not phosphorylated by the kinase. The kinase phosphorylates the 59 kD component of eIF-4G to the extent of 0.25 phosphate per mole of eIF-4G. Phosphorylation of eIF-4F and eIF-4B does not affect their ability to support the binding of mRNA to small ribosomal subunits in vitro. Images Fig. 2 Fig. 3 PMID:16666331

A portrait of tissue phosphoprotein stability in the clinical tissue procurement process.

PubMed

Espina, Virginia; Edmiston, Kirsten H; Heiby, Michael; Pierobon, Mariaelena; Sciro, Manuela; Merritt, Barbara; Banks, Stacey; Deng, Jianghong; VanMeter, Amy J; Geho, David H; Pastore, Lucia; Sennesh, Joel; Petricoin, Emanuel F; Liotta, Lance A

2008-10-01

Little is known about the preanalytical fluctuations of phosphoproteins during tissue procurement for molecular profiling. This information is crucial to establish guidelines for the reliable measurement of these analytes. To develop phosphoprotein profiles of tissue subjected to the trauma of excision, we measured the fidelity of 53 signal pathway phosphoproteins over time in tissue specimens procured in a community clinical practice. This information provides strategies for potential surrogate markers of stability and the design of phosphoprotein preservative/fixation solutions. Eleven different specimen collection time course experiments revealed augmentation (+/-20% from the time 0 sample) of signal pathway phosphoprotein levels as well as decreases over time independent of tissue type, post-translational modification, and protein subcellular location (tissues included breast, colon, lung, ovary, and uterus (endometrium/myometrium) and metastatic melanoma). Comparison across tissue specimens showed an >20% decrease of protein kinase B (AKT) Ser-473 (p < 0.002) and myristoylated alanine-rich C-kinase substrate protein Ser-152/156 (p < 0.0001) within the first 90-min postexcision. Proteins in apoptotic (cleaved caspase-3 Asp-175 (p < 0.001)), proliferation/survival/hypoxia (IRS-1 Ser-612 (p < 0.0003), AMP-activated protein kinase beta Ser-108 (p < 0.005), ERK Thr-202/Tyr-204 (p < 0.003), and GSK3alphabeta Ser-21/9 (p < 0.01)), and transcription factor pathways (STAT1 Tyr-701 (p < 0.005) and cAMP response element-binding protein Ser-133 (p < 0.01)) showed >20% increases within 90-min postprocurement. Endothelial nitric-oxide synthase Ser-1177 did not change over the time period evaluated with breast or leiomyoma tissue. Treatment with phosphatase or kinase inhibitors alone revealed that tissue kinase pathways are active ex vivo. Combinations of kinase and phosphatase inhibitors appeared to stabilize proteins that exhibited increases in the presence of phosphatase inhibitors alone (ATF-2 Thr-71, SAPK/JNK Thr-183/Tyr-185, STAT1 Tyr-701, JAK1 Tyr-1022/1023, and PAK1/PAK2 Ser-199/204/192/197). This time course study 1) establishes the dynamic nature of specific phosphoproteins in excised tissue, 2) demonstrates augmented phosphorylation in the presence of phosphatase inhibitors, 3) shows that kinase inhibitors block the upsurge in phosphorylation of phosphoproteins, 4) provides a rational strategy for room temperature preservation of proteins, and 5) constitutes a foundation for developing evidence-based tissue procurement guidelines.

Salidroside attenuates inflammatory responses by suppressing nuclear factor-κB and mitogen activated protein kinases activation in lipopolysaccharide-induced mastitis in mice.

PubMed

Li, Depeng; Fu, Yunhe; Zhang, Wen; Su, Gaoli; Liu, Bo; Guo, Mengyao; Li, Fengyang; Liang, Dejie; Liu, Zhicheng; Zhang, Xichen; Cao, Yongguo; Zhang, Naisheng; Yang, Zhengtao

2013-01-01

Mastitis is defined as inflammation of the mammary gland in domestic dairy animals and humans. Salidroside, a major component isolated from Rhodiola rosea L., has potent anti-inflammatory properties, but whether it can be used in mastitis treatment has not yet been investigated. The aim of this study was to assess the protective effects of salidroside against lipopolysaccharide (LPS)-induced mastitis in mice and the mechanism of action. We used a mouse mastitis model in which mammary gland inflammation was induced by LPS challenge. Salidroside administered 1 h before LPS infusion significantly attenuated inflammatory cell infiltration, reduced the activity of myeloperoxidase in mammary tissue, and decreased the concentration of tumor necrosis factor-α, interleukin (IL)-1β, and IL-6 in a dose-dependent manner. Further studies revealed that salidroside down-regulated phosphorylation of LPS-induced nuclear transcription factor-kappaB (NF-κB) p65 and inhibitor of NF-κB α (IκBα) in the NF-κB signal pathway, and suppressed phosphorylation of p38, extracellular signal-regulated kinase (ERK) and c-jun NH(2)-terminal kinase (JNK) in MAPKs signal pathways. This study demonstrates that salidroside is an effective suppressor of inflammation and may be a candidate for the prophylaxis of mastitis.

In Vivo Overexpression of Tissue-Nonspecific Alkaline Phosphatase Increases Skeletal Mineralization and Affects the Phosphorylation Status of Osteopontin

PubMed Central

Narisawa, Sonoko; Yadav, Manisha C.; Millán, José Luis

2013-01-01

Functional ablation of tissue-nonspecific alkaline phosphatase (TNAP) (Alpl−/− mice) leads to hypophosphatasia, characterized by rickets/osteomalacia attributable to elevated levels of extracellular inorganic pyrophosphate, a potent mineralization inhibitor. Osteopontin (OPN) is also elevated in the plasma and skeleton of Alpl−/− mice. Phosphorylated OPN is known to inhibit mineralization, however, the phosphorylation status of the increased OPN found in Alpl−/− mice is unknown. Here, we generated a transgenic mouse line expressing human TNAP under control of an osteoblast-specific Col1a1 promoter (Col1a1-Tnap). The transgene is expressed in osteoblasts, periosteum, and cortical bones, and plasma levels of TNAP in mice expressing Col1a1-Tnap are 10-20 times higher than those of wild-type mice. The Col1a1-Tnap animals are healthy and exhibit increased bone mineralization by microCT analysis. Crossbreeding of Col1a1-Tnap transgenic mice to Alpl−/− mice rescues the lethal hypophosphatasia phenotype characteristic of this disease model. Osteoblasts from [Col1a1-Tnap] mice mineralize better than non-transgenic controls and osteoblasts from [Col1a1-Tnap+/−; Alpl−/−] mice are able to mineralize to the level of Alpl+/− heterozygous osteoblasts, while Alpl−/− osteoblasts show no mineralization. We found that the increased levels of OPN in bone tissue of Alpl−/− mice are comprised of phosphorylated forms of OPN while WT and [Col1a1-Tnap+/−; Alpl−/−] mice had both phosphorylated and dephosphorylated forms of OPN. OPN from [Col1a1-Tnap] osteoblasts were more phosphorylated than non-transgenic control cells. Titanium dioxide-liquid chromatography and tandem mass spectrometry analysis revealed that OPN peptides derived from Alpl−/− bone and osteoblasts yielded a higher proportion of phosphorylated peptides than samples from WT mice, and at least two phosphopeptides, p(S174FQVS178DEQY182PDAT186DEDLT191)SHMK and FRIp(S299HELES304S305S306S307)EVN, with one non-localized site each, appear to be preferred sites of TNAP action on OPN. Our data suggest that the pro-mineralization role of TNAP may be related not only to its accepted pyrophosphatase activity but also to its ability to modify the phosphorylation status of OPN. PMID:23427088

Progerin phosphorylation in interphase is lower and less mechanosensitive than lamin-A,C in iPS-derived mesenchymal stem cells

PubMed Central

Cho, Sangkyun; Abbas, Amal; Ivanovska, Irena L.; Xia, Yuntao; Tewari, Manu; Discher, Dennis E.

2018-01-01

ABSTRACT Interphase phosphorylation of lamin-A,C depends dynamically on a cell's microenvironment, including the stiffness of extracellular matrix. However, phosphorylation dynamics is poorly understood for diseased forms such as progerin, a permanently farnesylated mutant of LMNA that accelerates aging of stiff and mechanically stressed tissues. Here, fine-excision alignment mass spectrometry (FEA-MS) is developed to quantify progerin and its phosphorylation levels in patient iPS cells differentiated to mesenchymal stem cells (MSCs). The stoichiometry of total A-type lamins (including progerin) versus B-type lamins measured for Progeria iPS-MSCs prove similar to that of normal MSCs, with total A-type lamins more abundant than B-type lamins. However, progerin behaves more like farnesylated B-type lamins in mechanically-induced segregation from nuclear blebs. Phosphorylation of progerin at multiple sites in iPS-MSCs cultured on rigid plastic is also lower than that of normal lamin-A and C. Reduction of nuclear tension upon i) cell rounding/detachment from plastic, ii) culture on soft gels, and iii) inhibition of actomyosin stress increases phosphorylation and degradation of lamin-C > lamin-A > progerin. Such mechano-sensitivity diminishes, however, with passage as progerin and DNA damage accumulate. Lastly, transcription-regulating retinoids exert equal effects on both diseased and normal A-type lamins, suggesting a differential mechano-responsiveness might best explain the stiff tissue defects in Progeria. PMID:29619860

PI3K Phosphorylation Is Linked to Improved Electrical Excitability in an In Vitro Engineered Heart Tissue Disease Model System.

PubMed

Kana, Kujaany; Song, Hannah; Laschinger, Carol; Zandstra, Peter W; Radisic, Milica

2015-09-01

Myocardial infarction, a prevalent cardiovascular disease, is associated with cardiomyocyte cell death, and eventually heart failure. Cardiac tissue engineering has provided hopes for alternative treatment options, and high-fidelity tissue models for drug discovery. The signal transduction mechanisms relayed in response to mechanoelectrical (physical) stimulation or biochemical stimulation (hormones, cytokines, or drugs) in engineered heart tissues (EHTs) are poorly understood. In this study, an EHT model was used to elucidate the signaling mechanisms involved when insulin was applied in the presence of electrical stimulation, a stimulus that mimics functional heart tissue environment in vitro. EHTs were insulin treated, electrically stimulated, or applied in combination (insulin and electrical stimulation). Electrical excitability parameters (excitation threshold and maximum capture rate) were measured. Protein kinase B (AKT) and phosphatidylinositol-3-kinase (PI3K) phosphorylation revealed that insulin and electrical stimulation relayed electrical excitability through two separate signaling cascades, while there was a negative crosstalk between sustained activation of AKT and PI3K.

A Secreted Effector Protein of Ustilago maydis Guides Maize Leaf Cells to Form Tumors

PubMed Central

Redkar, Amey; Hoser, Rafal; Schilling, Lena; Zechmann, Bernd; Krzymowska, Magdalena; Walbot, Virginia; Doehlemann, Gunther

2015-01-01

The biotrophic smut fungus Ustilago maydis infects all aerial organs of maize (Zea mays) and induces tumors in the plant tissues. U. maydis deploys many effector proteins to manipulate its host. Previously, deletion analysis demonstrated that several effectors have important functions in inducing tumor expansion specifically in maize leaves. Here, we present the functional characterization of the effector See1 (Seedling efficient effector1). See1 is required for the reactivation of plant DNA synthesis, which is crucial for tumor progression in leaf cells. By contrast, See1 does not affect tumor formation in immature tassel floral tissues, where maize cell proliferation occurs independent of fungal infection. See1 interacts with a maize homolog of SGT1 (Suppressor of G2 allele of skp1), a factor acting in cell cycle progression in yeast (Saccharomyces cerevisiae) and an important component of plant and human innate immunity. See1 interferes with the MAPK-triggered phosphorylation of maize SGT1 at a monocot-specific phosphorylation site. We propose that See1 interferes with SGT1 activity, resulting in both modulation of immune responses and reactivation of DNA synthesis in leaf cells. This identifies See1 as a fungal effector that directly and specifically contributes to the formation of leaf tumors in maize. PMID:25888589

The evidence basis for coenzyme Q therapy in oxidative phosphorylation disease.

PubMed

Haas, Richard H

2007-06-01

The evidence supporting a treatment benefit for coenzyme Q10 (CoQ10) in primary mitochondrial disease (mitochondrial disease) whilst positive is limited. Mitochondrial disease in this context is defined as genetic disease causing an impairment in mitochondrial oxidative phosphorylation (OXPHOS). There are no treatment trials achieving the highest Level I evidence designation. Reasons for this include the relative rarity of mitochondrial disease, the heterogeneity of mitochondrial disease, the natural cofactor status and easy 'over the counter availability' of CoQ10 all of which make funding for the necessary large blinded clinical trials unlikely. At this time the best evidence for efficacy comes from controlled trials in common cardiovascular and neurodegenerative diseases with mitochondrial and OXPHOS dysfunction the etiology of which is most likely multifactorial with environmental factors playing on a background of genetic predisposition. There remain questions about dosing, bioavailability, tissue penetration and intracellular distribution of orally administered CoQ10, a compound which is endogenously produced within the mitochondria of all cells. In some mitochondrial diseases and other commoner disorders such as cardiac disease and Parkinson's disease low mitochondrial or tissue levels of CoQ10 have been demonstrated providing an obvious rationale for supplementation. This paper discusses the current state of the evidence supporting the use of CoQ10 in mitochondrial disease.

Physiological stress and ethanol accumulation in tree stems and woody tissues at sublethal temperatures from fire

Treesearch

Rick G. Kelsey; Douglas J. Westlind

2017-01-01

The lethal temperature limit is 60 degrees Celsius (°C) for plant tissues, including trees, with lower temperatures causing heat stress. As fire injury increases on tree stems, there is an accompanying rise in tissue ethanol concentrations, physiologically linked to impaired mitochondrial oxidative phosphorylation energy production. We theorize that sublethal tissue...

Regulatory role of tumor necrosis factor receptor-associated factor 6 in breast cancer by activating the protein kinase B/glycogen synthase kinase 3β signaling pathway.

PubMed

Shen, Hongyu; Li, Liangpeng; Yang, Sujin; Wang, Dandan; Zhou, Siying; Chen, Xiu; Tang, Jinhai

2017-08-01

Tumor necrosis factor receptor-associated factor 6 (TRAF6) is an endogenous adaptor of innate and adaptive immune responses, and serves a crucial role in tumor necrosis factor receptor and toll‑like/interleukin‑1 receptor signaling. Although studies have demonstrated that TRAF6 has oncogenic activity, its potential contributions to breast cancer in human remains largely uninvestigated. The present study examined the expression levels and function of TRAF6 in breast carcinoma (n=32) and adjacent healthy (n=25) tissue samples. Compared with adjacent healthy tissues, TRAF6 protein expression levels were significantly upregulated in breast cancer tissues. Reverse transcription‑quantitative polymerase chain reaction analysis revealed a significant upregulation of the cellular proliferative marker Ki‑67 and proliferation cell nuclear antigen expression levels in breast carcinoma specimens. Furthermore, protein expression levels of the accessory molecule, transforming growth factor β‑activated kinase 1 (TAK1), were significantly increased in breast cancer patients, as detected by western blot analysis. As determined by MTT assay, TRAF6 exerted profoundly proliferative effects in the MCF‑7 breast cancer cell line; however, these detrimental effects were ameliorated by TAK1 inhibition. Notably, protein kinase B (AKT)/glycogen synthase kinase (GSK)3β phosphorylation levels were markedly upregulated in breast cancer samples, compared with adjacent healthy tissues. In conclusion, an altered TRAF6‑TAK1 axis and its corresponding downstream AKT/GSK3β signaling molecules may contribute to breast cancer progression. Therefore, TRAF6 may represent a potential therapeutic target for the treatment of breast cancer.

TGF-β signaling is often attenuated during hepatotumorigenesis, but is retained for the malignancy of hepatocellular carcinoma cells.

PubMed

Mu, Xiaoxin; Lin, Shu; Yang, Junhua; Chen, Chen; Chen, Yun; Herzig, Maryanne C; Washburn, Kenneth; Halff, Glenn A; Walter, Christi A; Sun, Beicheng; Sun, Lu-Zhe

2013-01-01

The role of transforming growth factor-beta (TGF-β) signaling in hepatocarcinogenesis remains controversial. We aimed to reveal TGF-β signaling status in human and murine tissues of hepatocellular carcinoma (HCC) and the mechanisms that mediate TGF-β's role in regulating HCC malignancy. Here, TGF-β pathway component expression and activation in human and murine HCC tissues were measured with quantitative RT-PCR and Western blotting assays. The role of TGF-β receptor and Smad signaling in the growth and survival of several HCC cell lines was determined with several in vitro and in vivo approaches. We found that TGF-β receptor II (TβRII) expression was downregulated in two different HCC patient cohorts. Consistently, Smad3 phosphorylation was also downregulated in HCC tissues in comparison to that in adjacent normal tissues. Interestingly, many HCC cell lines were sensitive to TGF-β and growth-inhibited by exogenous TGF-β. However, stable knockdown of TβRII inhibited cell growth on plastic and in soft agar, and induced apoptosis resulting in suppressed subcutaneous tumor growth and metastatic potential in vivo. Furthermore, knockdown of Smad4 also led to a significant inhibition of growth on plastic and in soft agar with concomitant increase of apoptosis, PTEN expression, and reduced nuclear accumulation of linker region-phosphorylated Smad3. Taken together, TGF-β signaling pathway plays a dichotomous role in hepatocellular carcinogenesis. It appears to suppress HCC development, but is retained for HCC cell survival and malignancy. Furthermore, Smad4 can mediate both growth inhibitory activity induced by exogenous TGF-β and the survival activity induced by autocrine TGF-β revealing a delicate selection of the two opposing activities of TGF-β during HCC evolution.

Salicylate Treatment Improves Age-Associated Vascular Endothelial Dysfunction: Potential Role of Nuclear Factor κB and Forkhead Box O Phosphorylation

PubMed Central

Durrant, Jessica R.; Connell, Melanie L.; Folian, Brian J.; Donato, Anthony J.; Seals, Douglas R.

2011-01-01

We hypothesized that I kappa B kinase (IKK)-mediated nuclear factor kappa B and forkhead BoxO3a phosphorylation will be associated with age-related endothelial dysfunction. Endothelium-dependent dilation and aortic protein expression/phosphorylation were determined in young and old male B6D2F1 mice and old mice treated with the IKK inhibitor, salicylate. IKK activation was greater in old mice and was associated with greater nitrotyrosine and cytokines. Endothelium-dependent dilation, nitric oxide (NO), and endothelial NO synthase phosphorylation were lower in old mice. Endothelium-dependent dilation and NO bioavailability were restored by a superoxide dismutase mimetic. Nuclear factor kappa B and forkhead BoxO3a phosphorylation were greater in old and were associated with increased expression/activity of nicotinamide adenine dinucleotide phosphate oxidase and lower manganese superoxide dismutase expression. Salicylate lowered IKK phosphorylation and reversed age-associated changes in nitrotyrosine, endothelium-dependent dilation, NO bioavailability, endothelial NO synthase, nuclear factor kappa B and forkhead BoxO3a phosphorylation, nicotinamide adenine dinucleotide phosphate oxidase, and manganese superoxide dismutase. Increased activation of IKK with advancing age stimulates nuclear factor kappa B and inactivates forkhead BoxO3a. This altered transcription factor activation contributes to a pro-inflammatory/pro-oxidative arterial phenotype that is characterized by increased cytokines and nicotinamide adenine dinucleotide phosphate oxidase and decreased manganese superoxide dismutase leading to oxidative stress-mediated endothelial dysfunction. PMID:21303813

Coarse-Grained Molecular Simulation of Epidermal Growth Factor Receptor Protein Tyrosine Kinase Multi-Site Self-Phosphorylation

PubMed Central

Koland, John G.

2014-01-01

Upon the ligand-dependent dimerization of the epidermal growth factor receptor (EGFR), the intrinsic protein tyrosine kinase (PTK) activity of one receptor monomer is activated, and the dimeric receptor undergoes self-phosphorylation at any of eight candidate phosphorylation sites (P-sites) in either of the two C-terminal (CT) domains. While the structures of the extracellular ligand binding and intracellular PTK domains are known, that of the ∼225-amino acid CT domain is not, presumably because it is disordered. Receptor phosphorylation on CT domain P-sites is critical in signaling because of the binding of specific signaling effector molecules to individual phosphorylated P-sites. To investigate how the combination of conventional substrate recognition and the unique topological factors involved in the CT domain self-phosphorylation reaction lead to selectivity in P-site phosphorylation, we performed coarse-grained molecular simulations of the P-site/catalytic site binding reactions that precede EGFR self-phosphorylation events. Our results indicate that self-phosphorylation of the dimeric EGFR, although generally believed to occur in trans, may well occur with a similar efficiency in cis, with the P-sites of both receptor monomers being phosphorylated to a similar extent. An exception was the case of the most kinase-proximal P-site-992, the catalytic site binding of which occurred exclusively in cis via an intramolecular reaction. We discovered that the in cis interaction of P-site-992 with the catalytic site was facilitated by a cleft between the N-terminal and C-terminal lobes of the PTK domain that allows the short CT domain sequence tethering P-site-992 to the PTK core to reach the catalytic site. Our work provides several new mechanistic insights into the EGFR self-phosphorylation reaction, and demonstrates the potential of coarse-grained molecular simulation approaches for investigating the complexities of self-phosphorylation in molecules such as EGFR (HER/ErbB) family receptors and growth factor receptor PTKs in general. PMID:24453959

IL-17 Promotes Angiogenic Factors IL-6, IL-8, and Vegf Production via Stat1 in Lung Adenocarcinoma.

PubMed

Huang, Qi; Duan, Limin; Qian, Xin; Fan, Jinshuo; Lv, Zhilei; Zhang, Xiuxiu; Han, Jieli; Wu, Feng; Guo, Mengfei; Hu, Guorong; Du, Jiao; Chen, Caiyun; Jin, Yang

2016-11-07

Inflammation and angiogenesis are two hallmarks of carcinoma. The proinflammatory cytokine interleukin-17 (IL-17) facilitates angiogenesis in lung cancer; however, the underlying mechanism is not fully understood. In this study, tumour microvessel density (MVD) was positively associated with IL-17, interleukin-6 (IL-6), interleukin-8 (IL-8), and vascular endothelial cell growth factor (VEGF) expression in human lung adenocarcinoma tissues, and it was increased in tumour tissues of A549-IL-17 cell-bearing nude mice. Importantly, positive correlations were also detected between IL-17 expression and IL-6, IL-8 and VEGF expression in human lung adenocarcinoma tissues. Furthermore, IL-6, IL-8 and VEGF production, as well as STAT1 phosphorylation, were increased in tumour tissues of A549-IL-17 cell-bearing nude mice in vivo and in A549 and H292 cells following IL-17 stimulation in vitro. In addition, STAT1 knockdown using an inhibitor and siRNA attenuated the IL-17-mediated increases in IL-6, IL-8 and VEGF expression in A549 and H292 cells. In conclusion, IL-17 may promote the production of the angiogenic inducers IL-6, IL-8 and VEGF via STAT1 signalling in lung adenocarcinoma.

Understanding the influence of phosphorylation and polysialylation of gelatin on mineralization and osteogenic differentiation.

PubMed

Arora, Aditya; Katti, Dhirendra S

2016-08-01

Post-translational modifications such as phosphorylation and sialylation impart crucial functions such as mineral deposition and osteogenic differentiation to non-collagenous bone matrix proteins. In this work, the influence of phosphorylation and polysialylation of gelatin on mineralization in simulated body fluid (SBF) and on osteogenic differentiation of mesenchymal stem cells (MSC) was studied. It was observed that increase in phosphorylation could be directly correlated with the mineralization ability of phosphorylated gelatin in SBF. The total calcium and phosphate deposited increased with increase in degree of phosphorylation and was >3 fold higher on the highest degree of phosphorylation. Whereas, polysialylation did not have any significant influence on mineral deposition in SBF. On the other hand, when MSCs were cultured on polysialylated surfaces they showed relatively higher cell elongation with 1.5 fold higher cell aspect ratio, higher alkaline phosphatase activity and 3 fold higher mineral deposition when compared to control and phosphorylated gelatin surfaces. In conclusion, phosphorylation and polysialylation of gelatin show a significant influence on mineralization and osteogenic differentiation respectively which can be advantageously used for bone tissue engineering. Copyright © 2016 Elsevier B.V. All rights reserved.

Liver tumor formation by a mutant retinoblastoma protein in the transgenic mice is caused by an upregulation of c-Myc target genes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Bo; Hikosaka, Keisuke; Sultana, Nishat

2012-01-06

Highlights: Black-Right-Pointing-Pointer Fifty percent of the mutant Rb transgenic mice produced liver tumors. Black-Right-Pointing-Pointer In the tumor, Foxm1, Skp2, Bmi1 and AP-1 mRNAs were up-regulated. Black-Right-Pointing-Pointer No increase in expression of the Myc-target genes was observed in the non-tumorous liver. Black-Right-Pointing-Pointer Tumor formation depends on up-regulation of the Myc-target genes. -- Abstract: The retinoblastoma (Rb) tumor suppressor encodes a nuclear phosphoprotein that regulates cellular proliferation, apoptosis and differentiation. In order to adapt itself to these biological functions, Rb is subjected to modification cycle, phosphorylation and dephosphorylation. To directly determine the effect of phosphorylation-resistant Rb on liver development and function, wemore » generated transgenic mice expressing phosphorylation-resistant human mutant Rb (mt-Rb) under the control of the rat hepatocyte nuclear factor-1 gene promoter/enhancer. Expression of mt-Rb in the liver resulted in macroscopic neoplastic nodules (adenomas) with {approx}50% incidence within 15 months old. Interestingly, quantitative reverse transcriptase-PCR analysis showed that c-Myc was up-regulated in the liver of mt-Rb transgenic mice irrespective of having tumor tissues or no tumor. In tumor tissues, several c-Myc target genes, Foxm1, c-Jun, c-Fos, Bmi1 and Skp2, were also up-regulated dramatically. We determined whether mt-Rb activated the Myc promoter in the HTP9 cells and demonstrated that mt-Rb acted as an inhibitor of wild-type Rb-induced repression on the Myc promoter. Our results suggest that continued upregulation of c-Myc target genes promotes the liver tumor formation after about 1 year of age.« less

Glucose stimulates protein synthesis in skeletal muscle of neonatal pigs through an AMPK- and mTOR-independent process.

PubMed

Jeyapalan, Asumthia S; Orellana, Renan A; Suryawan, Agus; O'Connor, Pamela M J; Nguyen, Hanh V; Escobar, Jeffery; Frank, Jason W; Davis, Teresa A

2007-08-01

Skeletal muscle protein synthesis is elevated in neonates in part due to an enhanced response to the rise in insulin and amino acids after eating. In vitro studies suggest that glucose plays a role in protein synthesis regulation. To determine whether glucose, independently of insulin and amino acids, is involved in the postprandial rise in skeletal muscle protein synthesis, pancreatic-substrate clamps were performed in neonatal pigs. Insulin secretion was inhibited with somatostatin and insulin was infused to reproduce fasting or fed levels, while glucose and amino acids were clamped at fasting or fed levels. Fractional protein synthesis rates and translational control mechanisms were examined. Raising glucose alone increased protein synthesis in fast-twitch glycolytic muscles but not in other tissues. The response in muscle was associated with increased phosphorylation of protein kinase B (PKB) and enhanced formation of the active eIF4E.eIF4G complex but no change in phosphorylation of AMP-activated protein kinase (AMPK), tuberous sclerosis complex 2 (TSC2), mammalian target of rapamycin (mTOR), 4E-binding protein-1 (4E-BP1), ribosomal protein S6 kinase (S6K1), or eukaryotic elongation factor 2 (eEF2). Raising glucose, insulin, and amino acids increased protein synthesis in most tissues. The response in muscle was associated with phosphorylation of PKB, mTOR, S6K1, and 4E-BP1 and enhanced eIF4E.eIF4G formation. The results suggest that the postprandial rise in glucose, independently of insulin and amino acids, stimulates protein synthesis in neonates, and this response is specific to fast-twitch glycolytic muscle and occurs by AMPK- and mTOR-independent pathways.

Smad signaling pathway is a pivotal component of tissue inhibitor of metalloproteinases-3 regulation by transforming growth factor beta in human chondrocytes.

PubMed

Qureshi, Hamid Yaqoob; Ricci, Gemma; Zafarullah, Muhammad

2008-09-01

Transforming growth factor beta (TGF-beta1) promotes cartilage matrix synthesis and induces tissue inhibitor of metalloproteinases-3 (TIMP-3), which inhibits matrix metalloproteinases, aggrecanases and TNF-alpha-converting enzyme implicated in articular cartilage degradation and joint inflammation. TGF-beta1 activates Akt, ERK and Smad2 pathways in chondrocytes. Here we investigated previously unexplored roles of specific Smads in TGF-beta1 induction of TIMP-3 gene by pharmacological and genetic knockdown approaches. TGF-beta1-induced Smad2 phosphorylation and TIMP-3 protein expression could be inhibited by the Smad2/3 phosphorylation inhibitors, PD169316 and SB203580 and by Smad2-specific siRNA. Specific inhibitor of Smad3 (SIS3) and Smad3 siRNA abolished TGF-beta induction of TIMP-3. Smad2/3 siRNAs also down regulated TIMP-3 promoter-driven luciferase activities, suggesting transcriptional regulation. SiRNA-driven co-Smad4 knockdown abrogated TIMP-3 augmentation by TGF-beta. TIMP-3 promoter deletion analysis revealed that -828 deletion retains the original promoter activity while -333 and -167 deletions display somewhat reduced activity suggesting that most of the TGF-beta-responsive, cis-acting elements are found in the -333 fragment. Chromatin Immunoprecipitation (ChIP) analysis confirmed binding of Smad2 and Smad4 with the -940 and -333 promoter sequences. These results suggest that receptor-activated Smad2 and Smad3 and co-Smad4 critically mediate TGF-beta-stimulated TIMP-3 expression in human chondrocytes and TIMP-3 gene is a target of Smad signaling pathway.

Molecular dynamics study of the phosphorylation effect on the conformational states of the C-terminal domain of RNA polymerase II.

PubMed

Yonezawa, Yasushige

2014-05-01

The carboxyl-terminal domain (CTD) of RNA polymerase II in eukaryotes regulates mRNA processing processes by recruiting various regulation factors. A main function of the CTD relies on the heptad consensus sequence (YSPTSPS). The CTD dynamically changes its conformational state to recognize and bind different regulation factors. The dynamical conformation changes are caused by modifications, mainly phosphorylation and dephosphorylation, to the serine residues. In this study, we investigate the conformational states of the unit consensus CTD peptide with various phosphorylation patterns of the serine residues by extended ensemble simulations. The results show that the CTD without phosphorylation has a flexible disordered structure distributed between twisted and extended states, but phosphorylation tends to reduce the conformational space. It was found that phosphorylation induces a β-turn around the phosphorylated serine residue and the cis conformation of the proline residue significantly inhibits the β-turn formation. The β-turn should contribute to specific CTD binding of the different regulation factors by changing the conformation propensity combined with induced fit.

Thyroid hormone increases fibroblast growth factor receptor expression and disrupts cell mechanics in the developing organ of corti

PubMed Central

2013-01-01

Background Thyroid hormones regulate growth and development. However, the molecular mechanisms by which thyroid hormone regulates cell structural development are not fully understood. The mammalian cochlea is an intriguing system to examine these mechanisms, as cellular structure plays a key role in tissue development, and thyroid hormone is required for the maturation of the cochlea in the first postnatal week. Results In hypothyroid conditions, we found disruptions in sensory outer hair cell morphology and fewer microtubules in non-sensory supporting pillar cells. To test the functional consequences of these cytoskeletal defects on cell mechanics, we combined atomic force microscopy with live cell imaging. Hypothyroidism stiffened outer hair cells and supporting pillar cells, but pillar cells ultimately showed reduced cell stiffness, in part from a lack of microtubules. Analyses of changes in transcription and protein phosphorylation suggest that hypothyroidism prolonged expression of fibroblast growth factor receptors, and decreased phosphorylated Cofilin. Conclusions These findings demonstrate that thyroid hormones may be involved in coordinating the processes that regulate cytoskeletal dynamics and suggest that manipulating thyroid hormone sensitivity might provide insight into the relationship between cytoskeletal formation and developing cell mechanical properties. PMID:23394545

Linking γ-aminobutyric acid A receptor to epidermal growth factor receptor pathways activation in human prostate cancer.

PubMed

Wu, Weijuan; Yang, Qing; Fung, Kar-Ming; Humphreys, Mitchell R; Brame, Lacy S; Cao, Amy; Fang, Yu-Ting; Shih, Pin-Tsen; Kropp, Bradley P; Lin, Hsueh-Kung

2014-03-05

Neuroendocrine (NE) differentiation has been attributed to the progression of castration-resistant prostate cancer (CRPC). Growth factor pathways including the epidermal growth factor receptor (EGFR) signaling have been implicated in the development of NE features and progression to a castration-resistant phenotype. However, upstream molecules that regulate the growth factor pathway remain largely unknown. Using androgen-insensitive bone metastasis PC-3 cells and androgen-sensitive lymph node metastasis LNCaP cells derived from human prostate cancer (PCa) patients, we demonstrated that γ-aminobutyric acid A receptor (GABA(A)R) ligand (GABA) and agonist (isoguvacine) stimulate cell proliferation, enhance EGF family members expression, and activate EGFR and a downstream signaling molecule, Src, in both PC-3 and LNCaP cells. Inclusion of a GABA(A)R antagonist, picrotoxin, or an EGFR tyrosine kinase inhibitor, Gefitinib (ZD1839 or Iressa), blocked isoguvacine and GABA-stimulated cell growth, trans-phospohorylation of EGFR, and tyrosyl phosphorylation of Src in both PCa cell lines. Spatial distributions of GABAAR α₁ and phosphorylated Src (Tyr416) were studied in human prostate tissues by immunohistochemistry. In contrast to extremely low or absence of GABA(A)R α₁-positive immunoreactivity in normal prostate epithelium, elevated GABA(A)R α₁ immunoreactivity was detected in prostate carcinomatous glands. Similarly, immunoreactivity of phospho-Src (Tyr416) was specifically localized and limited to the nucleoli of all invasive prostate carcinoma cells, but negative in normal tissues. Strong GABAAR α₁ immunoreactivity was spatially adjacent to the neoplastic glands where strong phospho-Src (Tyr416)-positive immunoreactivity was demonstrated, but not in adjacent to normal glands. These results suggest that the GABA signaling is linked to the EGFR pathway and may work through autocrine or paracine mechanism to promote CRPC progression. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

In vivo differential effects of fasting, re-feeding, insulin and insulin stimulation time course on insulin signaling pathway components in peripheral tissues.

PubMed

Agouni, Abdelali; Owen, Carl; Czopek, Alicja; Mody, Nimesh; Delibegovic, Mirela

2010-10-08

Components of the insulin receptor signaling pathway are probably some of the best studied ones. Even though methods for studying these components are well established, the in vivo effects of different fasting regimens, and the time course of insulin receptor phosphorylation and that of its downstream components in insulin-sensitive peripheral tissues have not been analyzed in detail. When assessing insulin signaling, it may be beneficial to drive insulin levels as low as possible by performing an overnight fast before injecting a supra-physiological dose of insulin. Recent studies have shown however that 5 or 6 h fast in mice is sufficient to assess physiological responses to insulin and/or glucose in glucose tolerance tests, insulin tolerance tests and euglycemic hyperinsulinemic clamp studies. Moreover, mice are nocturnal feeders, with ∼70% of their daily caloric intake occurring during the dark cycle, and their metabolic rate is much higher than humans. Therefore, an overnight fast in mice is closer to starvation than just food withdrawal. Thus our aim was to assess insulin signaling components from the insulin receptor to downstream targets IRS1, Akt/PKB, GSK3, Erk1/2 and ribosomal protein S6 in muscle, liver and adipose tissue in 5 h versus 16 h (overnight) fasted mice, and the time course (0-30 min) of these phosphorylation events. We also assessed whether re-feeding under 5 h and 16 h fasting conditions was a more robust stimulus than insulin alone. Our study determines that a short food withdrawal from mice, for a period of 5 h, results in a similar insulin-stimulated response in phosphorylation events as the long overnight fast, presenting a more physiological experimental set up. We also demonstrate that in vivo, insulin-stimulated phosphorylation of its signaling components is different between different peripheral tissues, and depending on the tissue(s) and protein(s) of interest, an appropriate time course should be chosen. Copyright © 2010 Elsevier Inc. All rights reserved.

Inhibition of Expression of the S100A8 Gene Encoding the S100 Calcium-Binding Protein A8 Promotes Apoptosis by Suppressing the Phosphorylation of Protein Kinase B (Akt) in Endometrial Carcinoma and HEC-1A Cells.

PubMed

Liu, Chang; Xing, Guangyang; Wu, Cailiang; Zhu, Jun; Wei, Min; Liu, Dajiang; Ge, Yan; Chen, Yao; Lei, Ting; Yang, Yongxiu

2018-03-29

BACKGROUND The aim of this study was to investigate the expression and silencing of the S100A8 gene, which encodes the S100 calcium-binding protein A8 (S100A8), and apoptosis and phosphorylation of protein kinase B (Akt) in tissue samples of endometrial carcinoma and HEC-1A endometrial adenocarcinoma cells in vitro. MATERIAL AND METHODS Immunohistochemistry (IHC) was used to detect expression of the S100A8 protein in 74 tissue samples of endometrial cancer and 22 normal endometrial tissue samples. A stable S100A8 gene knockdown cell line was constructed using lentiviral packing short hairpin RNA (shRNA) transfected into HEC-1A cells. S100A8 mRNA and S100A8 protein levels were detected by quantitative reverse transcription-polymerase chain reaction (qRT-PCR) and Western blotting. The effects of expression of the S100A8 gene by endometrial cancer cells was investigated by the MTT assay, cell cycle and apoptotic assays, qRT-PCR, and Western blotting. RESULTS IHC showed high levels of expression of S100A8 protein in endometrial carcinoma tissues, and HEC-1A adenocarcinoma cells (in G1 and G2). Increased expression of S100A8 protein was found endometrial cancer tissues compared with normal endometrial tissues (79.7% vs. 4.5%). S100A8 gene knockdown reduced cell proliferation in the HEC-1A cells compared with control cells, induced cell apoptosis, inhibited the phosphorylation of protein kinase B (Akt), and induced the expression of pro-apoptotic genes, including the cytochrome C gene, CYCS, BAD, BAX, FOXO1, FOXO3, CASP9, and CASP3. CONCLUSIONS In endometrial carcinoma cells, down-regulation of the S100A8 gene induced cell apoptosis via inhibition of the phosphorylated or active form of protein kinase B (Akt).

Inhibition of Expression of the S100A8 Gene Encoding the S100 Calcium-Binding Protein A8 Promotes Apoptosis by Suppressing the Phosphorylation of Protein Kinase B (Akt) in Endometrial Carcinoma and HEC-1A Cells

PubMed Central

Liu, Chang; Xing, Guangyang; Wu, Cailiang; Zhu, Jun; Wei, Min; Liu, Dajiang; Ge, Yan; Chen, Yao; Lei, Ting

2018-01-01

Background The aim of this study was to investigate the expression and silencing of the S100A8 gene, which encodes the S100 calcium-binding protein A8 (S100A8), and apoptosis and phosphorylation of protein kinase B (Akt) in tissue samples of endometrial carcinoma and HEC-1A endometrial adenocarcinoma cells in vitro. Material/Methods Immunohistochemistry (IHC) was used to detect expression of the S100A8 protein in 74 tissue samples of endometrial cancer and 22 normal endometrial tissue samples. A stable S100A8 gene knockdown cell line was constructed using lentiviral packing short hairpin RNA (shRNA) transfected into HEC-1A cells. S100A8 mRNA and S100A8 protein levels were detected by quantitative reverse transcription-polymerase chain reaction (qRT-PCR) and Western blotting. The effects of expression of the S100A8 gene by endometrial cancer cells was investigated by the MTT assay, cell cycle and apoptotic assays, qRT-PCR, and Western blotting. Results IHC showed high levels of expression of S100A8 protein in endometrial carcinoma tissues, and HEC-1A adenocarcinoma cells (in G1 and G2). Increased expression of S100A8 protein was found endometrial cancer tissues compared with normal endometrial tissues (79.7% vs. 4.5%). S100A8 gene knockdown reduced cell proliferation in the HEC-1A cells compared with control cells, induced cell apoptosis, inhibited the phosphorylation of protein kinase B (Akt), and induced the expression of pro-apoptotic genes, including the cytochrome C gene, CYCS, BAD, BAX, FOXO1, FOXO3, CASP9, and CASP3. Conclusions In endometrial carcinoma cells, down-regulation of the S100A8 gene induced cell apoptosis via inhibition of the phosphorylated or active form of protein kinase B (Akt). PMID:29595187

PKD Phosphorylation as Novel Pathway of KV11.1 Regulation.

PubMed

Steffensen, Annette Buur; Bomholtz, Sofia Hammami; Andersen, Martin Nybo; Olsen, Jesper Velgaard; Mutsaers, Nancy; Lundegaard, Pia Rengtved; Lundby, Alicia; Schmitt, Nicole

2018-06-27

The voltage-gated potassium channel KV11.1 has been originally cloned from the brain and is expressed in a variety of tissues. The role of phosphorylation for channel function is a matter of debate. In this study, we aimed to elucidate the extent and role of protein kinase D mediated phosphorylation. We employed mass spectrometry, whole-cell patch clamp electrophysiology, confocal microscopy, site-directed mutagenesis, and western blotting. Using brain tissue from rat and mouse, we mapped several phosphorylated KV11.1 residues by LC-MS mass spectrometry and identified protein kinase D (PKD1) as possible regulatory kinase. Co-expression of KV11.1 with PKD1 reduced current amplitudes without altering protein levels or surface expression of the channel. Based on LC-MS results from in vivo and HEK293 cell experiments we chose four KV11.1 mutant candidates for further functional analysis. Ablation of the putative PKD phosphorylation site in the mutant S284A increased the maximal current indicating S284 as a main PKD target in KV11.1. Our data might help mitigating a long-standing controversy in the field regarding PKC regulation of KV11.1. We propose that PKD1 mediates the PKC effects on KV11.1 and we found that PKD targets S284 in the N-terminus of the channel. © 2018 The Author(s). Published by S. Karger AG, Basel.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, Yi; Li, Dechun; Zhao, Xin

Resistance to Fas Ligand (FasL) mediated apoptosis plays an important role in tumorigenesis. Decoy receptor 3 (DcR3) is reported to interact with FasL and is overexpressed in some malignant tumors. We sought to investigate the role of DcR3 in resistance to FasL in pancreatic cancer. We compared expression of apoptosis related genes between FasL-resistant SW1990 and FasL-sensitive Patu8988 pancreatic cell lines by microarray analysis. We explored the impact of siRNA knockdown of, or exogenous supplementation with, DcR3 on FasL-induced cell growth inhibition in pancreatic cancer cell lines and expression of proteins involved in apoptotic signaling. We assessed the level ofmore » DcR3 protein and ERK1/2 phosphorylation in tumor and non-tumor tissue samples of 66 patients with pancreatic carcinoma. RNAi knockdown of DcR3 expression in SW1990 cells reduced resistance to FasL-induced apoptosis, and supplementation of Patu8988 with rDcR3 had the opposite effect. RNAi knockdown of DcR3 in SW1990 cells elevated expression of caspase 3, 8 and 9, and reduced ERK1/2 phosphorylation (P < 0.05), but did not alter phosphorylated-Akt expression. 47 tumor tissue specimens, but only 15 matched non-tumor specimens stained for DcR3 (χ{sup 2} = 31.1447, P < 0.001). The proliferation index of DcR3 positive specimens (14.26  ±  2.67%) was significantly higher than that of DcR3 negative specimens (43.58  ±  7.88%, P < 0.01). DcR3 expression positively correlated with p-ERK1/2 expression in pancreatic cancer tissues (r = 0.607, P < 0.001). DcR3 enhances ERK1/2 phosphorylation and opposes FasL signaling in pancreatic cancer cells. - Highlights: • We investigated the role of DcR3 in FasL resistance in pancreatic cancer. • Knockdown of DcR3 in SW1990 cells reduced resistance to FasL-induced apoptosis. • DcR3 knockdown also elevated caspase expression, and reduced ERK1/2 phosphorylation. • Tumor and non-tumor tissues were collected from 66 pancreatic carcinoma patients. • 47 tumor tissue specimens, but only 15 matched non-tumor specimens contained DcR3.« less

Serine 302 Phosphorylation of Mouse Insulin Receptor Substrate 1 (IRS1) Is Dispensable for Normal Insulin Signaling and Feedback Regulation by Hepatic S6 Kinase*

PubMed Central

Copps, Kyle D.; Hançer, Nancy J.; Qiu, Wei; White, Morris F.

2016-01-01

Constitutive activation of the mammalian target of rapamycin complex 1 and S6 kinase (mTORC1→ S6K) attenuates insulin-stimulated Akt activity in certain tumors in part through “feedback” phosphorylation of the upstream insulin receptor substrate 1 (IRS1). However, the significance of this mechanism for regulating insulin sensitivity in normal tissue remains unclear. We investigated the function of Ser-302 in mouse IRS1, the major site of its phosphorylation by S6K in vitro, through genetic knock-in of a serine-to-alanine mutation (A302). Although insulin rapidly stimulated feedback phosphorylation of Ser-302 in mouse liver and muscle, homozygous A302 mice (A/A) and their knock-in controls (S/S) exhibited similar glucose homeostasis and muscle insulin signaling. Furthermore, both A302 and control primary hepatocytes from which Irs2 was deleted showed marked inhibition of insulin-stimulated IRS1 tyrosine phosphorylation and PI3K binding after emetine treatment to raise intracellular amino acids and activate mTORC1 → S6K signaling. To specifically activate mTORC1 in mouse tissue, we deleted hepatic Tsc1 using Cre adenovirus. Although it moderately decreased IRS1/PI3K association and Akt phosphorylation in liver, Tsc1 deletion failed to cause glucose intolerance or promote hyperinsulinemia in mixed background A/A or S/S mice. Moreover, Tsc1 deletion failed to stimulate phospho-Ser-302 or other putative S6K sites within IRS1, whereas ribosomal S6 protein was constitutively phosphorylated. Following acute Tsc1 deletion from hepatocytes, Akt phosphorylation, but not IRS1/PI3K association, was rapidly restored by treatment with the mTORC1 inhibitor rapamycin. Thus, within the hepatic compartment, mTORC1 → S6K signaling regulates Akt largely through IRS-independent means with little effect upon physiologic insulin sensitivity. PMID:26846849

The Fibroblast Growth Factor signaling pathway.

PubMed

Ornitz, David M; Itoh, Nobuyuki

2015-01-01

The signaling component of the mammalian Fibroblast Growth Factor (FGF) family is comprised of eighteen secreted proteins that interact with four signaling tyrosine kinase FGF receptors (FGFRs). Interaction of FGF ligands with their signaling receptors is regulated by protein or proteoglycan cofactors and by extracellular binding proteins. Activated FGFRs phosphorylate specific tyrosine residues that mediate interaction with cytosolic adaptor proteins and the RAS-MAPK, PI3K-AKT, PLCγ, and STAT intracellular signaling pathways. Four structurally related intracellular non-signaling FGFs interact with and regulate the family of voltage gated sodium channels. Members of the FGF family function in the earliest stages of embryonic development and during organogenesis to maintain progenitor cells and mediate their growth, differentiation, survival, and patterning. FGFs also have roles in adult tissues where they mediate metabolic functions, tissue repair, and regeneration, often by reactivating developmental signaling pathways. Consistent with the presence of FGFs in almost all tissues and organs, aberrant activity of the pathway is associated with developmental defects that disrupt organogenesis, impair the response to injury, and result in metabolic disorders, and cancer. For further resources related to this article, please visit the WIREs website. © 2015 The Authors. WIREs Developmental Biology published by Wiley Periodicals, Inc.

An Online Guided E-Journal Exercise in Pre-Clerkship Years: Oxidative Phosphorylation in Brown Adipose Tissue

ERIC Educational Resources Information Center

Abali, Emine Ercikan; Phadtare, Sangita; Galt, Jim; Brodsky, Barbara

2014-01-01

The rationale for this mandatory, guided online e-journal exercise is to foster the ability of students to independently read medical and scientific literature in a critical manner and to integrate journal reading with their basic science knowledge. After a lecture on oxidative phosphorylation, students were assigned to read an article on brown…

Nuclear NF-kappaB p65 phosphorylation at serine 276 by protein kinase A contributes to the malignant phenotype of head and neck cancer.

PubMed

Arun, Pattatheyil; Brown, Matthew S; Ehsanian, Reza; Chen, Zhong; Van Waes, Carter

2009-10-01

Aberrant nuclear activation and phosphorylation of the canonical NF-kappaB subunit RELA/p65 at Serine-536 by inhibitor kappaB kinase is prevalent in head and neck squamous cell carcinoma (HNSCC), but the role of other kinases in NF-kappaB activation has not been well defined. Here, we investigated the prevalence and function of p65-Ser276 phosphorylation by protein kinase A (PKA) in the malignant phenotype and gene transactivation, and studied p65-Ser276 as a potential target for therapy. Phospho and total p65 protein expression and localization were determined in HNSCC tissue array and in cell lines. The effects of the PKA inhibitor H-89 on NF-kappaB activation, downstream gene expression, cell proliferation and cell cycle were examined. Knockdown of PKA by specific siRNA confirmed the specificity. NF-kappaB p65 phosphorylated at Ser276 was prevalent in HNSCC and adjacent dysplastic mucosa, but localized to the cytoplasm in normal mucosa. In HNSCC lines, tumor necrosis factor-alpha (TNF-alpha) significantly increased, whereas H-89 inhibited constitutive and TNF-alpha-induced nuclear p65 (Ser276) phosphorylation, and significantly suppressed NF-kappaB and target gene IL-8 reporter activity. Knockdown of PKA by small interfering RNA inhibited NF-kappaB, IL-8, and BCL-XL reporter gene activities. H-89 suppressed cell proliferation, induced cell death, and blocked the cell cycle in G(1)-S phase. Consistent with its biological effects, H-89 down-modulated expression of NF-kappaB-related genes Cyclin D1, BCL2, BCL-XL, COX2, IL-8, and VEGF, as well as induced cell cycle inhibitor p21(CIP1/WAF1), while suppressing proliferative marker Ki67. NF-kappaB p65 (Ser276) phosphorylation by PKA promotes the malignant phenotype and holds potential as a therapeutic target in HNSCC.

Saw palmetto extract suppresses insulin-like growth factor-I signaling and induces stress-activated protein kinase/c-Jun N-terminal kinase phosphorylation in human prostate epithelial cells.

PubMed

Wadsworth, Teri L; Carroll, Julie M; Mallinson, Rebecca A; Roberts, Charles T; Roselli, Charles E

2004-07-01

A common alternative therapy for benign prostatic hyperplasia (BPH) is the extract from the fruit of saw palmetto (SPE). BPH is caused by nonmalignant growth of epithelial and stromal elements of the prostate. IGF action is important for prostate growth and development, and changes in the IGF system have been documented in BPH tissues. The main signaling pathways activated by the binding of IGF-I to the IGF-I receptor (IGF-IR) are the ERK arm of the MAPK cascade and the phosphoinositol-3-kinase (PI3K)/protein kinase B (PKB/Akt) cascade. We tested the hypothesis that SPE suppresses growth and induces apoptosis in the P69 prostate epithelial cell line by inhibiting IGF-I signaling. Treatment with 150 microg/ml SPE for 24 h decreased IGF-I-induced proliferation of P69 cells and induced cleavage of the enzyme poly(ADP-ribose)polymerase (PARP), an index of apoptosis. Treatment of serum-starved P69 cells with 150 microg/ml SPE for 6 h reduced IGF-I-induced phosphorylation of Akt (assessed by Western blot) and Akt activity (assessed by an Akt kinase assay). Western blot analysis showed that SPE reduced IGF-I-induced phosphorylation of the adapter protein insulin receptor substrate-1 and decreased downstream effects of Akt activation, including increased cyclin D1 levels and phosphorylation of glycogen synthase kinase-3 and p70(s6k). There was no effect on IGF-I-induced phosphorylation of MAPK, IGF-IR, or Shc. Treatment of starved cells with SPE alone induced phosphorylation the proapoptotic protein JNK. SPE treatment may relieve symptoms of BPH, in part, by inhibiting specific components of the IGF-I signaling pathway and inducing JNK activation, thus mediating antiproliferative and proapoptotic effects on prostate epithelia.

Contribution of mammalian target of rapamycin in the pathophysiology of cirrhotic cardiomyopathy.

PubMed

Saeedi Saravi, Seyed Soheil; Ghazi-Khansari, Mahmoud; Ejtemaei Mehr, Shahram; Nobakht, Maliheh; Mousavi, Seyyedeh Elaheh; Dehpour, Ahmad Reza

2016-05-21

To explore the role of mammalian target of rapamycin (mTOR) in the pathogenesis of cirrhotic cardiomyopathy and the potential of rapamycin to improve this pathologic condition. Male albino Wistar rats weighing 100-120 g were treated with tetrachloride carbon (CCl4) for 8 wk to induce cirrhosis. Subsequently, animals were administered rapamycin (2 mg/kg per day). The QTc intervals were calculated in a 5-min electrocardiogram. Then, the left ventricular papillary muscles were isolated to examine inotropic responsiveness to β-adrenergic stimulation using a standard organ bath equipped by Powerlab system. Phosphorylated-mTOR localization in left ventricles was immunohistochemically assessed, and ventricular tumor necrosis factor (TNF)-α was measured. Western blot was used to measure levels of ventricular phosphorylated-mTOR protein. Cirrhosis was confirmed by hematoxylin and eosin staining of liver tissues, visual observation of lethargy, weight loss, jaundice, brown urine, ascites, liver stiffness, and a significant increase of spleen weight (P < 0.001). A significant prolongation in QTc intervals occurred in cirrhotic rats exposed to CCl4 (P < 0.001), while this prolongation was decreased with rapamycin treatment (P < 0.01). CCl4-induced cirrhosis caused a significant decrease of contractile responsiveness to isoproterenol stimulation and a significant increase in cardiac TNF-α. These findings were correlated with data from western blot and immunohistochemical studies on phosphorylated-mTOR expression in left ventricles. Phosphorylated-mTOR was significantly enhanced in cirrhotic rats, especially in the endothelium, compared to controls. Rapamycin treatment significantly increased contractile force and myocardial localization of phosphorylated-mTOR and decreased cardiac TNF-α concentration compared to cirrhotic rats with no treatment. In this study, we demonstrated a potential role for cardiac mTOR in the pathophysiology of cirrhotic cardiomyopathy. Rapamycin normalized the inotropic effect and altered phosphorylated-mTOR expression and myocardial localization in cirrhotic rats.

Sulphation of secreted phosphoprotein I (SPPI, osteopontin) is associated with mineralized tissue formation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nagata, T.; Todescan, R.; Goldberg, H.A.

Secreted phosphoprotein I (SPPI) is a prominent structural protein in mineralized connective tissues. Rat bone cells in culture produce several forms of SPPI that differ in post-translational modifications such as phosphorylation and sulphation. To determine the significance of protein sulphation in bone formation, the synthesis of SPPI was studied in vitro using rat bone marrow cells (RBMC) which form bone-like tissue when grown in the presence of dexamethasone (Dex) and beta-glycerophosphate (beta-GP). In the presence of 10(-7) M Dex SPPI expression was stimulated 4-5-fold. Radiolabelling multilayered RBMCs for 48 h with (35S)-methionine, Na2(35SO4), or Na3(32PO4) revealed that two major phosphorylatedmore » forms of SPPI were secreted into the culture medium: a highly phosphorylated form migrating at 44 kDa on 15% SDS-PAGE and a less phosphorylated 55 kDa form. In the mineralized tissue formed in the presence of Dex and beta-GP, both forms of SPPI, in addition to proteoglycans and a 67 kDa protein, incorporated significant amounts of (35SO4). Sulphation of SPPI was not observed in the absence of mineral formation, indicating that the sulphation of SPPI is closely associated with mineralization and that it can be used as a sensitive and specific marker for the osteoblastic phenotype.« less

Vasodilator-stimulated Phosphoprotein (VASP) Regulates Actin Polymerization and Contraction in Airway Smooth Muscle by a Vinculin-dependent Mechanism*

PubMed Central

Wu, Yidi; Gunst, Susan J.

2015-01-01

Vasodilator-stimulated phosphoprotein (VASP) can catalyze actin polymerization by elongating actin filaments. The elongation mechanism involves VASP oligomerization and its binding to profilin, a G-actin chaperone. Actin polymerization is required for tension generation during the contraction of airway smooth muscle (ASM); however, the role of VASP in regulating actin dynamics in ASM is not known. We stimulated ASM cells and tissues with the contractile agonist acetylcholine (ACh) or the adenylyl cyclase activator, forskolin (FSK), a dilatory agent. ACh and FSK stimulated VASP Ser157 phosphorylation by different kinases. Inhibition of VASP Ser157 phosphorylation by expression of the mutant VASP S157A in ASM tissues suppressed VASP phosphorylation and membrane localization in response to ACh, and also inhibited contraction and actin polymerization. ACh but not FSK triggered the formation of VASP-VASP complexes as well as VASP-vinculin and VASP-profilin complexes at membrane sites. VASP-VASP complex formation and the interaction of VASP with vinculin and profilin were inhibited by expression of the inactive vinculin mutant, vinculin Y1065F, but VASP phosphorylation and membrane localization were unaffected. We conclude that VASP phosphorylation at Ser157 mediates its localization at the membrane, but that VASP Ser157 phosphorylation and membrane localization are not sufficient to activate its actin catalytic activity. The interaction of VASP with activated vinculin at membrane adhesion sites is a necessary prerequisite for VASP-mediated molecular processes necessary for actin polymerization. Our results show that VASP is a critical regulator of actin dynamics and tension generation during the contractile activation of ASM. PMID:25759389

Characterization of a Rapid, Blue Light-Mediated Change in Detectable Phosphorylation of a Plasma Membrane Protein from Etiolated Pea (Pisum sativum L.) Seedlings.

PubMed

Short, T W; Briggs, W R

1990-01-01

When crude microsomal membranes from apical stem segments of etiolated Pisum sativum L. cv Alaska are mixed in vitro with gamma-[(32)P]ATP, a phosphorylated band of apparent molecular mass 120 kilodaltons can be detected on autoradiographs of sodium dodecyl sulfate electrophoresis gels. If the stem sections are exposed to blue light immediately prior to membrane isolation, this band is not evident. The response is observed most strongly in membranes from the growing region of the stem, but no 120 kilodalton radiolabeled band is detected in membranes from the developing buds. Fluence-response curves for the reaction show that the system responds to blue light above about 0.3 micromole per square meter, and the visible phosphorylation completely disappears above 200 micromoles per square meter. Reciprocity is valid for the system, because varying illumination time or fluence rate give similar results. If the stem segments are left in the dark following a saturating blue irradiation, the radio-labeled band begins to return after about 10 minutes and is as intense as that from the dark controls within 45 to 60 minutes. A protein that comigrates with the phosphorylated protein on polyacrylamide gels is also undetectable after saturating blue light irradiations. The fluence range in which the protein band disappears is the same as that for the disappearance of the phosphorylation band. Its dark recovery kinetics and tissue distribution also parallel those for the phosphorylation. In vitro irradiation of the isolated membranes also results in a phosphorylation change at that molecular mass, but in the opposite direction. Comparisons of the kinetics, tissue distribution, and dark recovery of the phosphorylation response with those published for blue light-mediated phototropism or rapid growth inhibition indicate that the phosphorylation could be linked to one or both of those reactions. However, the fluence-response relationships for the change in detectable phosphorylation match quite closely those reported for phototropism but not those for growth inhibition. Blue light has also been found to regulate the capacity for in vitro phosphorylation of a second protein. It has an apparent molecular mass of 84 kilodaltons and is localized primarily in basal stem sections.

Rho Kinase (ROCK) collaborates with Pak to Regulate Actin Polymerization and Contraction in Airway Smooth Muscle.

PubMed

Zhang, Wenwu; Bhetwal, Bhupal P; Gunst, Susan J

2018-05-10

The mechanisms by which Rho kinase (ROCK) regulates airway smooth muscle contraction were determined in tracheal smooth muscle tissues. ROCK may mediate smooth muscle contraction by inhibiting myosin regulatory light chain (RLC) phosphatase. ROCK can also regulate F-actin dynamics during cell migration, and actin polymerization is critical for airway smooth muscle contraction. Our results show that ROCK does not regulate airway smooth muscle contraction by inhibiting myosin RLC phosphatase or by stimulating myosin RLC phosphorylation. We find that ROCK regulates airway smooth muscle contraction by activating the serine-threonine kinase Pak, which mediates the activation of Cdc42 and Neuronal-Wiskott-Aldrich Syndrome protein (N-WASp). N-WASP transmits signals from cdc42 to the Arp2/3 complex for the nucleation of actin filaments. These results demonstrate a novel molecular function for ROCK in the regulation of Pak and cdc42 activation that is critical for the processes of actin polymerization and contractility in airway smooth muscle. Rho kinase (ROCK), a RhoA GTPase effector, can regulate the contraction of airway and other smooth muscle tissues. In some tissues, ROCK can inhibit myosin regulatory light chain (RLC) phosphatase, which increases the phosphorylation of myosin RLC and promotes smooth muscle contraction. ROCK can also regulate cell motility and migration by affecting F-actin dynamics. Actin polymerization is stimulated by contractile agonists in airway smooth muscle tissues and is required for contractile tension development in addition to myosin RLC phosphorylation. We investigated the mechanisms by which ROCK regulates the contractility of tracheal smooth muscle tissues by expressing a kinase inactive mutant of ROCK, ROCK-K121G, in the tissues or by treating them with the ROCK inhibitor, H-1152P. Our results show no role for ROCK in the regulation of non-muscle or smooth muscle myosin RLC phosphorylation during contractile stimulation in this tissue. We find that ROCK regulates airway smooth muscle contraction by mediating activation of the serine-threonine kinase, Pak, to promote actin polymerization. Pak catalyzes paxillin phosphorylation on Ser273 and coupling of the GIT1-βPIX-Pak signaling module to paxillin, which activates the GEF activity βPIX towards cdc42. Cdc42 is required for the activation of Neuronal Wiskott-Aldrich Syndrome protein (N-WASp), which transmits signals from cdc42 to the Arp2/3 complex for the nucleation of actin filaments. Our results demonstrate a novel molecular function for ROCK in the regulation of Pak and cdc42 activation that is critical for the processes of actin polymerization and contractility in airway smooth muscle. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

Tyrosine phosphorylation and proteolytic cleavage of Notch are required for non-canonical Notch/Abl signaling in Drosophila axon guidance.

PubMed

Kannan, Ramakrishnan; Cox, Eric; Wang, Lei; Kuzina, Irina; Gu, Qun; Giniger, Edward

2018-01-17

Notch signaling is required for the development and physiology of nearly every tissue in metazoans. Much of Notch signaling is mediated by transcriptional regulation of downstream target genes, but Notch controls axon patterning in Drosophila by local modulation of Abl tyrosine kinase signaling, via direct interactions with the Abl co-factors Disabled and Trio. Here, we show that Notch-Abl axonal signaling requires both of the proteolytic cleavage events that initiate canonical Notch signaling. We further show that some Notch protein is tyrosine phosphorylated in Drosophila , that this form of the protein is selectively associated with Disabled and Trio, and that relevant tyrosines are essential for Notch-dependent axon patterning but not for canonical Notch-dependent regulation of cell fate. Based on these data, we propose a model for the molecular mechanism by which Notch controls Abl signaling in Drosophila axons. © 2018. Published by The Company of Biologists Ltd.

Quantitative phosphoproteomics analysis reveals a key role of insulin growth factor 1 receptor (IGF1R) tyrosine kinase in human sperm capacitation.

PubMed

Wang, Jing; Qi, Lin; Huang, Shaoping; Zhou, Tao; Guo, Yueshuai; Wang, Gaigai; Guo, Xuejiang; Zhou, Zuomin; Sha, Jiahao

2015-04-01

One of the most important changes during sperm capacitation is the enhancement of tyrosine phosphorylation. However, the mechanisms of protein tyrosine phosphorylation during sperm capacitation are not well studied. We used label-free quantitative phosphoproteomics to investigate the overall phosphorylation events during sperm capacitation in humans and identified 231 sites with increased phosphorylation levels. Motif analysis using the NetworKIN algorithm revealed that the activity of tyrosine phosphorylation kinases insulin growth factor 1 receptor (IGF1R)/insulin receptor is significantly enriched among the up-regulated phosphorylation substrates during capacitation. Western blotting further confirmed inhibition of IGF1R with inhibitors GSK1904529A and NVP-AEW541, which inhibited the increase in tyrosine phosphorylation levels during sperm capacitation. Additionally, sperm hyperactivated motility was also inhibited by GSK1904529A and NVP-AEW541 but could be up-regulated by insulin growth factor 1, the ligand of IGF1R. Thus, the IGF1R-mediated tyrosine phosphorylation pathway may play important roles in the regulation of sperm capacitation in humans and could be a target for improvement in sperm functions in infertile men. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

Exercise training protects against atherosclerotic risk factors through vascular NADPH oxidase, extracellular signal-regulated kinase 1/2 and stress-activated protein kinase/c-Jun N-terminal kinase downregulation in obese rats.

PubMed

Touati, Sabeur; Montezano, Augusto C I; Meziri, Fayçal; Riva, Catherine; Touyz, Rhian M; Laurant, Pascal

2015-02-01

Exercise training reverses atherosclerotic risk factors associated with metabolic syndrome and obesity. The aim of the present study was to determine the molecular anti-inflammatory, anti-oxidative and anti-atherogenic effects in aorta from rats with high-fat diet-induced obesity. Male Sprague-Dawley rats were placed on a high-fat (HFD) or control (CD) diet for 12 weeks. The HFD rats were then divided into four groups: (i) sedentary HFD-fed rats (HFD-S); (ii) exercise trained (motor treadmill 5 days/week, 60 min/day, 12 weeks) HFD-fed rats (HFD-Ex); (iii) modified diet (HFD to CD) sedentary rats (HF/CD-S); and (iv) an exercise-trained modified diet group (HF/CD-Ex). Tissue levels of NADPH oxidase (activity and expression), NADPH oxidase (Nox) 1, Nox2, Nox4, p47(phox) , superoxide dismutase (SOD)-1, angiotensin AT1 and AT2 receptors, phosphorylated mitogen-activated protein kinase (MAPK; extracellular signal-regulated kinase (ERK) 1/2, stress-activated protein kinase (SAPK)/c-Jun N-terminal kinase (JNK)) and vascular cell adhesion molecule-1 (VCAM-1) were determined in the aorta. Plasma cytokines (tumour necrosis factor (TNF)-α and interleukin (IL)-6) levels were also measured. Obesity was accompanied by increases in NADPH oxidase activity, p47(phox) translocation, Nox4 and VCAM-1 protein expression, MAPK (ERK1/2, SAPK/JNK) phosphorylation and plasma TNF-α and IL-6 levels. Exercise training and switching from the HFD to CD reversed almost all these molecular changes. In addition, training increased aortic SOD-1 protein expression and decreased ERK1/2 phosphorylation. These findings suggest that protective effects of exercise training on atherosclerotic risk factors induced by obesity are associated with downregulation of NADPH oxidase, ERK1/2 and SAPK/JNK activity and increased SOD-1 expression. © 2014 Wiley Publishing Asia Pty Ltd.

Deanol affects choline metabolism in peripheral tissues of mice.

PubMed

Haubrich, D R; Gerber, N H; Pflueger, A B

1981-08-01

Administration of 2-dimethylaminoethanol (deanol) to mice induced an increase in both the concentration and the rate of turnover of free choline in blood. Treatment with deanol also caused an increase in the concentration of choline in kidneys, and markedly inhibited the rates of oxidation and phosphorylation of intravenously administered [3H-methyl]choline. In the liver, deanol inhibited the rate of phosphorylation of [3H-methyl]choline, but did not inhibit its rate of oxidation or cause an increase in the level of free choline. These findings suggest that deanol increases the choline concentration in blood by inhibition of its metabolism in tissues. Deanol may ultimately produce its central cholinergic effects by inhibition of choline metabolism in peripheral tissues, causing free choline choline to accumulate in blood, enter the brain, and stimulate cholinergic receptors.

Low-Intensity Extracorporeal Shock Wave Therapy Enhances Brain-Derived Neurotrophic Factor Expression through PERK/ATF4 Signaling Pathway.

PubMed

Wang, Bohan; Ning, Hongxiu; Reed-Maldonado, Amanda B; Zhou, Jun; Ruan, Yajun; Zhou, Tie; Wang, Hsun Shuan; Oh, Byung Seok; Banie, Lia; Lin, Guiting; Lue, Tom F

2017-02-16

Low-intensity extracorporeal shock wave therapy (Li-ESWT) is used in the treatment of erectile dysfunction, but its mechanisms are not well understood. Previously, we found that Li-ESWT increased the expression of brain-derived neurotrophic factor (BDNF). Here we assessed the underlying signaling pathways in Schwann cells in vitro and in penis tissue in vivo after nerve injury. The result indicated that BDNF were significantly increased by the Li-ESWT after nerve injury, as well as the expression of BDNF in Schwann cells (SCs, RT4-D6P2T) in vitro. Li-ESWT activated the protein kinase RNA-like endoplasmic reticulum (ER) kinase (PERK) pathway by increasing the phosphorylation levels of PERK and eukaryotic initiation factor 2a (eIF2α), and enhanced activating transcription factor 4 (ATF4) in an energy-dependent manner. In addition, GSK2656157-an inhibitor of PERK-effectively inhibited the effect of Li-ESWT on the phosphorylation of PERK, eIF2α, and the expression of ATF4. Furthermore, silencing ATF4 dramatically attenuated the effect of Li-ESWT on the expression of BDNF, but had no effect on hypoxia-inducible factor (HIF)1α or glial cell-derived neurotrophic factor (GDNF) in Schwann cells. In conclusion, our findings shed new light on the underlying mechanisms by which Li-ESWT may stimulate the expression of BDNF through activation of PERK/ATF4 signaling pathway. This information may help to refine the use of Li-ESWT to further improve its clinical efficacy.

Low-Intensity Extracorporeal Shock Wave Therapy Enhances Brain-Derived Neurotrophic Factor Expression through PERK/ATF4 Signaling Pathway

PubMed Central

Wang, Bohan; Ning, Hongxiu; Reed-Maldonado, Amanda B.; Zhou, Jun; Ruan, Yajun; Zhou, Tie; Wang, Hsun Shuan; Oh, Byung Seok; Banie, Lia; Lin, Guiting; Lue, Tom F.

2017-01-01

Low-intensity extracorporeal shock wave therapy (Li-ESWT) is used in the treatment of erectile dysfunction, but its mechanisms are not well understood. Previously, we found that Li-ESWT increased the expression of brain-derived neurotrophic factor (BDNF). Here we assessed the underlying signaling pathways in Schwann cells in vitro and in penis tissue in vivo after nerve injury. The result indicated that BDNF were significantly increased by the Li-ESWT after nerve injury, as well as the expression of BDNF in Schwann cells (SCs, RT4-D6P2T) in vitro. Li-ESWT activated the protein kinase RNA-like endoplasmic reticulum (ER) kinase (PERK) pathway by increasing the phosphorylation levels of PERK and eukaryotic initiation factor 2a (eIF2α), and enhanced activating transcription factor 4 (ATF4) in an energy-dependent manner. In addition, GSK2656157—an inhibitor of PERK—effectively inhibited the effect of Li-ESWT on the phosphorylation of PERK, eIF2α, and the expression of ATF4. Furthermore, silencing ATF4 dramatically attenuated the effect of Li-ESWT on the expression of BDNF, but had no effect on hypoxia-inducible factor (HIF)1α or glial cell-derived neurotrophic factor (GDNF) in Schwann cells. In conclusion, our findings shed new light on the underlying mechanisms by which Li-ESWT may stimulate the expression of BDNF through activation of PERK/ATF4 signaling pathway. This information may help to refine the use of Li-ESWT to further improve its clinical efficacy. PMID:28212323

Contractile and mechanical properties of epithelia with perturbed actomyosin dynamics.

PubMed

Fischer, Sabine C; Blanchard, Guy B; Duque, Julia; Adams, Richard J; Arias, Alfonso Martinez; Guest, Simon D; Gorfinkiel, Nicole

2014-01-01

Mechanics has an important role during morphogenesis, both in the generation of forces driving cell shape changes and in determining the effective material properties of cells and tissues. Drosophila dorsal closure has emerged as a reference model system for investigating the interplay between tissue mechanics and cellular activity. During dorsal closure, the amnioserosa generates one of the major forces that drive closure through the apical contraction of its constituent cells. We combined quantitation of live data, genetic and mechanical perturbation and cell biology, to investigate how mechanical properties and contraction rate emerge from cytoskeletal activity. We found that a decrease in Myosin phosphorylation induces a fluidization of amnioserosa cells which become more compliant. Conversely, an increase in Myosin phosphorylation and an increase in actin linear polymerization induce a solidification of cells. Contrary to expectation, these two perturbations have an opposite effect on the strain rate of cells during DC. While an increase in actin polymerization increases the contraction rate of amnioserosa cells, an increase in Myosin phosphorylation gives rise to cells that contract very slowly. The quantification of how the perturbation induced by laser ablation decays throughout the tissue revealed that the tissue in these two mutant backgrounds reacts very differently. We suggest that the differences in the strain rate of cells in situations where Myosin activity or actin polymerization is increased arise from changes in how the contractile forces are transmitted and coordinated across the tissue through ECadherin-mediated adhesion. Altogether, our results show that there is an optimal level of Myosin activity to generate efficient contraction and suggest that the architecture of the actin cytoskeleton and the dynamics of adhesion complexes are important parameters for the emergence of coordinated activity throughout the tissue.

Contractile and Mechanical Properties of Epithelia with Perturbed Actomyosin Dynamics

PubMed Central

Fischer, Sabine C.; Blanchard, Guy B.; Duque, Julia; Adams, Richard J.; Arias, Alfonso Martinez; Guest, Simon D.; Gorfinkiel, Nicole

2014-01-01

Mechanics has an important role during morphogenesis, both in the generation of forces driving cell shape changes and in determining the effective material properties of cells and tissues. Drosophila dorsal closure has emerged as a reference model system for investigating the interplay between tissue mechanics and cellular activity. During dorsal closure, the amnioserosa generates one of the major forces that drive closure through the apical contraction of its constituent cells. We combined quantitation of live data, genetic and mechanical perturbation and cell biology, to investigate how mechanical properties and contraction rate emerge from cytoskeletal activity. We found that a decrease in Myosin phosphorylation induces a fluidization of amnioserosa cells which become more compliant. Conversely, an increase in Myosin phosphorylation and an increase in actin linear polymerization induce a solidification of cells. Contrary to expectation, these two perturbations have an opposite effect on the strain rate of cells during DC. While an increase in actin polymerization increases the contraction rate of amnioserosa cells, an increase in Myosin phosphorylation gives rise to cells that contract very slowly. The quantification of how the perturbation induced by laser ablation decays throughout the tissue revealed that the tissue in these two mutant backgrounds reacts very differently. We suggest that the differences in the strain rate of cells in situations where Myosin activity or actin polymerization is increased arise from changes in how the contractile forces are transmitted and coordinated across the tissue through ECadherin-mediated adhesion. Altogether, our results show that there is an optimal level of Myosin activity to generate efficient contraction and suggest that the architecture of the actin cytoskeleton and the dynamics of adhesion complexes are important parameters for the emergence of coordinated activity throughout the tissue. PMID:24759936

Growth arrest-specific protein 6 is hepatoprotective against murine ischemia/reperfusion injury.

PubMed

Llacuna, Laura; Bárcena, Cristina; Bellido-Martín, Lola; Fernández, Laura; Stefanovic, Milica; Marí, Montserrat; García-Ruiz, Carmen; Fernández-Checa, José C; García de Frutos, Pablo; Morales, Albert

2010-10-01

Growth arrest-specific gene 6 (GAS6) promotes growth and cell survival during tissue repair and development in different organs, including the liver. However, the specific role of GAS6 in liver ischemia/reperfusion (I/R) injury has not been previously addressed. Here we report an early increase in serum GAS6 levels after I/R exposure. Moreover, unlike wild-type (WT) mice, Gas6(-/-) mice were highly sensitive to partial hepatic I/R, with 90% of the mice dying within 12 hours of reperfusion because of massive hepatocellular injury. I/R induced early hepatic protein kinase B (AKT) phosphorylation in WT mice but not in Gas6(-/-) mice without significant changes in c-Jun N-terminal kinase phosphorylation or nuclear factor kappa B translocation, whereas hepatic interleukin-1β (IL-1β) and tumor necrosis factor (TNF) messenger RNA levels were higher in Gas6(-/-) mice versus WT mice. In line with the in vivo data, in vitro studies indicated that GAS6 induced AKT phosphorylation in primary mouse hepatocytes and thus protected them from hypoxia-induced cell death, whereas GAS6 diminished lipopolysaccharide-induced cytokine expression (IL-1β and TNF) in murine macrophages. Finally, recombinant GAS6 treatment in vivo not only rescued GAS6 knockout mice from severe I/R-induced liver damage but also attenuated hepatic damage in WT mice after I/R. Our data have revealed GAS6 to be a new player in liver I/R injury that is emerging as a potential therapeutic target for reducing postischemic hepatic damage.

Interleukin-6-driven progranulin expression increases cholangiocarcinoma growth by an Akt-dependent mechanism.

PubMed

Frampton, Gabriel; Invernizzi, Pietro; Bernuzzi, Francesca; Pae, Hae Yong; Quinn, Matthew; Horvat, Darijana; Galindo, Cheryl; Huang, Li; McMillin, Matthew; Cooper, Brandon; Rimassa, Lorenza; DeMorrow, Sharon

2012-02-01

Cholangiocarcinoma is a devastating cancer of biliary origin with limited treatment options. The growth factor, progranulin, is overexpressed in a number of tumours. The study aims were to assess the expression of progranulin in cholangiocarcinoma and to determine its effects on tumour growth. The expression and secretion of progranulin were evaluated in multiple cholangiocarcinoma cell lines and in clinical samples from patients with cholangiocarcinoma. The role of interleukin 6 (IL-6)-mediated signalling in the expression of progranulin was assessed using a combination of specific inhibitors and shRNA knockdown techniques. The effect of progranulin on proliferation and Akt activation and subsequent effects of FOXO1 phosphorylation were assessed in vitro. Progranulin knockdown cell lines were established, and the effects on cholangiocarcinoma growth were determined. Progranulin expression and secretion were upregulated in cholangiocarcinoma cell lines and tissue, which were in part via IL-6-mediated activation of the ERK1/2/RSK1/C/EBPβ pathway. Blocking any of these signalling molecules, by either pharmacological inhibitors or shRNA, prevented the IL-6-dependent activation of progranulin expression. Treatment of cholangiocarcinoma cells with recombinant progranulin increased cell proliferation in vitro by a mechanism involving Akt phosphorylation leading to phosphorylation and nuclear extrusion of FOXO1. Knockdown of progranulin expression in cholangiocarcinoma cells decreased the expression of proliferating cellular nuclear antigen, a marker of proliferative capacity, and slowed tumour growth in vivo. Evidence is presented for a role for progranulin as a novel growth factor regulating cholangiocarcinoma growth. Specific targeting of progranulin may represent an alternative for the development of therapeutic strategies.

Supplementation of chitosan alleviates high-fat diet-enhanced lipogenesis in rats via adenosine monophosphate (AMP)-activated protein kinase activation and inhibition of lipogenesis-associated genes.

PubMed

Chiu, Chen-Yuan; Chan, Im-Lam; Yang, Tsung-Han; Liu, Shing-Hwa; Chiang, Meng-Tsan

2015-03-25

This study investigated the role of chitosan in lipogenesis in high-fat diet-induced obese rats. The lipogenesis-associated genes and their upstream regulatory proteins were explored. Diet supplementation of chitosan efficiently decreased the increased weights in body, livers, and adipose tissues in high-fat diet-fed rats. Chitosan supplementation significantly raised the lipolysis rate; attenuated the adipocyte hypertrophy, triglyceride accumulation, and lipoprotein lipase activity in epididymal adipose tissues; and decreased hepatic enzyme activities of lipid biosynthesis. Chitosan supplementation significantly activated adenosine monophosphate (AMP)-activated protein kinase (AMPK) phosphorylation and attenuated high-fat diet-induced protein expressions of lipogenic transcription factors (PPAR-γ and SREBP1c) in livers and adipose tissues. Moreover, chitosan supplementation significantly inhibited the expressions of downstream lipogenic genes (FAS, HMGCR, FATP1, and FABP4) in livers and adipose tissues of high-fat diet-fed rats. These results demonstrate for the first time that chitosan supplementation alleviates high-fat diet-enhanced lipogenesis in rats via AMPK activation and lipogenesis-associated gene inhibition.

Phosphorylation decelerates conformational dynamics in bacterial translation elongation factors

PubMed Central

Talavera, Ariel; Hendrix, Jelle; Versées, Wim; Jurėnas, Dukas; Van Nerom, Katleen; Vandenberk, Niels; Singh, Ranjan Kumar; Konijnenberg, Albert; De Gieter, Steven; Castro-Roa, Daniel; Barth, Anders; De Greve, Henri; Sobott, Frank; Hofkens, Johan; Zenkin, Nikolay; Loris, Remy; Garcia-Pino, Abel

2018-01-01

Bacterial protein synthesis is intricately connected to metabolic rate. One of the ways in which bacteria respond to environmental stress is through posttranslational modifications of translation factors. Translation elongation factor Tu (EF-Tu) is methylated and phosphorylated in response to nutrient starvation upon entering stationary phase, and its phosphorylation is a crucial step in the pathway toward sporulation. We analyze how phosphorylation leads to inactivation of Escherichia coli EF-Tu. We provide structural and biophysical evidence that phosphorylation of EF-Tu at T382 acts as an efficient switch that turns off protein synthesis by decoupling nucleotide binding from the EF-Tu conformational cycle. Direct modifications of the EF-Tu switch I region or modifications in other regions stabilizing the β-hairpin state of switch I result in an effective allosteric trap that restricts the normal dynamics of EF-Tu and enables the evasion of the control exerted by nucleotides on G proteins. These results highlight stabilization of a phosphorylation-induced conformational trap as an essential mechanism for phosphoregulation of bacterial translation and metabolism. We propose that this mechanism may lead to the multisite phosphorylation state observed during dormancy and stationary phase. PMID:29546243

Preservation of Specific Protein Signaling States Using Heat Based Stabilizor System.

PubMed

Borén, Mats

2017-01-01

The ability to adequately measure the phosphorylation state of a protein has major biological as well as clinical relevance. Due to its variable nature, reversible protein phosphorylations are sensitive to changes in the tissue environment. Stabilizor TM T1 is a system for rapid inactivation of enzymatic activity in biological samples. Enzyme inactivation is accomplished using thermal denaturation in a rapid, homogeneous, and reproducible fashion without the need of added chemical inhibitors. Using pCREB(Ser133) as a model system, the applicability of the Stabilizor system to preserve a rapidly lost phosphorylation is shown.

ACTIVATION OF EXTRACELLULAR REGULATED KINASE AND MECHANISTIC TARGET OF RAPAMYCIN PATHWAY IN FOCAL CORTICAL DYSPLASIA

PubMed Central

Patil, Vinit V.; Guzman, Miguel; Carter, Angela N.; Rathore, Geetanjali; Yoshor, Daniel; Curry, Daniel; Wilfong, Angus; Agadi, Satish; Swann, John W.; Adesina, Adekunle M.; Bhattacharjee, Meenakshi B.; Anderson, Anne E.

2016-01-01

Neuropathology of resected brain tissue has revealed an association of focal cortical dysplasia (FCD) with drug resistant epilepsy (DRE). Recent studies have shown that the mechanistic target of rapamycin (mTOR) pathway is hyperactivated in FCD as evidenced by increased phosphorylation of the ribosomal protein S6 (S6) at serine 240/244 (S240/244), a downstream target of mTOR. Moreover, extracellular regulated kinase (ERK) has been shown to phosphorylate S6 at serine 235/236 (S235/236) and tuberous sclerosis complex 2 (TSC2) at serine 664 (S664) leading to hyperactive mTOR signaling. We evaluated ERK phosphorylation of S6 and TSC2 in two types of FCD (FCD I and FCDII) as a candidate mechanism contributing to mTOR pathway dysregulation in this disorder. Tissue samples from patients with tuberous sclerosis (TS) served as a positive control. Immunostaining for phospho-S6 (pS6240/244 and pS6235/236), phospho-ERK (pERK), and phospho-TSC2 (pTSC2) was performed on resected brain tissue with FCD and TS. We found increased pS6240/244 and pS6235/236 staining in FCD I, FCD II, and TS compared to normal appearing tissue, while pERK and pTSC2 staining was increased only in FCD IIb and TS tissue. Our results suggest that both the ERK and mTOR pathways are dysregulated in FCD and TS; however, the signaling alterations are different for FCD I as compared to FCD II and TS. PMID:26381727

Transforming growth factor-{beta}-inducible phosphorylation of Smad3.

PubMed

Wang, Guannan; Matsuura, Isao; He, Dongming; Liu, Fang

2009-04-10

Smad proteins transduce the transforming growth factor-beta (TGF-beta) signal at the cell surface into gene regulation in the nucleus. Upon TGF-beta treatment, the highly homologous Smad2 and Smad3 are phosphorylated by the TGF-beta receptor at the SSXS motif in the C-terminal tail. Here we show that in addition to the C-tail, three (S/T)-P sites in the Smad3 linker region, Ser(208), Ser(204), and Thr(179) are phosphorylated in response to TGF-beta. The linker phosphorylation peaks at 1 h after TGF-beta treatment, behind the peak of the C-tail phosphorylation. We provide evidence suggesting that the C-tail phosphorylation by the TGF-beta receptor is necessary for the TGF-beta-induced linker phosphorylation. Although the TGF-beta receptor is necessary for the linker phosphorylation, the receptor itself does not phosphorylate these sites. We further show that ERK is not responsible for TGF-beta-dependent phosphorylation of these three sites. We show that GSK3 accounts for TGF-beta-inducible Ser(204) phosphorylation. Flavopiridol, a pan-CDK inhibitor, abolishes TGF-beta-induced phosphorylation of Thr(179) and Ser(208), suggesting that the CDK family is responsible for phosphorylation of Thr(179) and Ser(208) in response to TGF-beta. Mutation of the linker phosphorylation sites to nonphosphorylatable residues increases the ability of Smad3 to activate a TGF-beta/Smad-target gene as well as the growth-inhibitory function of Smad3. Thus, these observations suggest that TGF-beta-induced phosphorylation of Smad3 linker sites inhibits its antiproliferative activity.

Anti-Inflammatory and Antioxidant Mechanism of Tangeretin in Activated Microglia.

PubMed

Lee, Yu Young; Lee, Eun-Jung; Park, Jin-Sun; Jang, Se-Eun; Kim, Dong-Hyun; Kim, Hee-Sun

2016-06-01

Tangeretin, a flavonoid from citrus fruit peels, has been proven to play an important role in anti-inflammatory responses and neuroprotective effects in several disease models, but further study is necessary for elucidating the detailed mechanisms of these effects. In this study, we examined the anti-inflammatory effect of tangeretin in lipopolysaccharide (LPS)-stimulated microglia. We first observed that tangeretin inhibited LPS-induced production of nitric oxide, tumor necrosis factor alpha, interleukin (IL)-6, and IL-1β, as well as LPS-induced mRNA expression of inducible nitric oxide synthases and cytokines. Additionally, we found that the activities, mRNA levels, and protein levels of matrix metalloproteinase (MMP)-3 and MMP-8 were inhibited, while the expression of tissue inhibitor of metalloproteinase-2 was enhanced by tangeretin in LPS-stimulated microglia. Further mechanistic study showed that tangeretin suppressed LPS-induced phosphorylation of mitogen-activated protein kinases and Akt. Also, tangeretin inhibited nuclear factor-κB by upregulating sirtuin 1 and 5'-adenosine monophosphate-activated protein kinase. We further demonstrated the antioxidant effect of tangeretin by showing that tangeretin inhibited reactive oxygen species production and p47(phox) phosphorylation, while enhancing the expression of heme oxygenase-1 and the DNA binding activity of nuclear factor-erythroid 2-related factor 2 to the antioxidant response element in LPS-stimulated microglia. Taken together, the results of the present study demonstrate that tangeretin possesses a potent anti-inflammatory and antioxidant effect in microglia.

Phosphorylation of serine 779 in fibroblast growth factor receptor 1 and 2 by protein kinase C(epsilon) regulates Ras/mitogen-activated protein kinase signaling and neuronal differentiation.

PubMed

Lonic, Ana; Powell, Jason A; Kong, Yang; Thomas, Daniel; Holien, Jessica K; Truong, Nhan; Parker, Michael W; Guthridge, Mark A

2013-05-24

The FGF receptors (FGFRs) control a multitude of cellular processes both during development and in the adult through the initiation of signaling cascades that regulate proliferation, survival, and differentiation. Although FGFR tyrosine phosphorylation and the recruitment of Src homology 2 domain proteins have been widely described, we have previously shown that FGFR is also phosphorylated on Ser(779) in response to ligand and binds the 14-3-3 family of phosphoserine/threonine-binding adaptor/scaffold proteins. However, whether this receptor phosphoserine mode of signaling is able to regulate specific signaling pathways and biological responses is unclear. Using PC12 pheochromocytoma cells and primary mouse bone marrow stromal cells as models for growth factor-regulated neuronal differentiation, we show that Ser(779) in the cytoplasmic domains of FGFR1 and FGFR2 is required for the sustained activation of Ras and ERK but not for other FGFR phosphotyrosine pathways. The regulation of Ras and ERK signaling by Ser(779) was critical not only for neuronal differentiation but also for cell survival under limiting growth factor concentrations. PKCε can phosphorylate Ser(779) in vitro, whereas overexpression of PKCε results in constitutive Ser(779) phosphorylation and enhanced PC12 cell differentiation. Furthermore, siRNA knockdown of PKCε reduces both growth factor-induced Ser(779) phosphorylation and neuronal differentiation. Our findings show that in addition to FGFR tyrosine phosphorylation, the phosphorylation of a conserved serine residue, Ser(779), can quantitatively control Ras/MAPK signaling to promote specific cellular responses.

Hydrogen sulfide oxidation is coupled to oxidative phosphorylation in mitochondria of Solemya reidi

DOE Office of Scientific and Technical Information (OSTI.GOV)

Powell, M.A.; Somero, G.N.

1986-08-01

Solemya reidi, a gutless clam found in sulfide-rich habitats, contains within its gills bacterial symbionts thought to oxidize sulfur compounds and provide a reduced carbon food source to the clam. However, the initial step or steps in sulfide oxidation occur in the animal tissue, and mitochondria isolated from both gill and symbiont-free foot tissue of the clam coupled the oxidation of sulfide to oxidative phosphorylation (adenosine triphosphate (ATP) synthesis). The ability of Solemya reidi to exploit directly the energy in sulfide for ATP synthesis is unprecedented, and suggests that sulfide-habitat animals that lack bacterial symbionts may also use sulfide asmore » an inorganic energy source.« less

Quantitative Assessment of Heterogeneity in Tumor Metabolism Using FDG-PET

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vriens, Dennis, E-mail: d.vriens@nucmed.umcn.nl; Disselhorst, Jonathan A.; Oyen, Wim J.G.

2012-04-01

Purpose: [{sup 18}F]-fluorodeoxyglucose-positron emission tomography (FDG-PET) images are usually quantitatively analyzed in 'whole-tumor' volumes of interest. Also parameters determined with dynamic PET acquisitions, such as the Patlak glucose metabolic rate (MR{sub glc}) and pharmacokinetic rate constants of two-tissue compartment modeling, are most often derived per lesion. We propose segmentation of tumors to determine tumor heterogeneity, potentially useful for dose-painting in radiotherapy and elucidating mechanisms of FDG uptake. Methods and Materials: In 41 patients with 104 lesions, dynamic FDG-PET was performed. On MR{sub glc} images, tumors were segmented in quartiles of background subtracted maximum MR{sub glc} (0%-25%, 25%-50%, 50%-75%, and 75%-100%).more » Pharmacokinetic analysis was performed using an irreversible two-tissue compartment model in the three segments with highest MR{sub glc} to determine the rate constants of FDG metabolism. Results: From the highest to the lowest quartile, significant decreases of uptake (K{sub 1}), washout (k{sub 2}), and phosphorylation (k{sub 3}) rate constants were seen with significant increases in tissue blood volume fraction (V{sub b}). Conclusions: Tumor regions with highest MR{sub glc} are characterized by high cellular uptake and phosphorylation rate constants with relatively low blood volume fractions. In regions with less metabolic activity, the blood volume fraction increases and cellular uptake, washout, and phosphorylation rate constants decrease. These results support the hypothesis that regional tumor glucose phosphorylation rate is not dependent on the transport of nutrients (i.e., FDG) to the tumor.« less

Optimum temperature in juvenile salmonids: connecting subcellular indicators to tissue function and whole-organism thermal optimum.

PubMed

Anttila, Katja; Casselman, Matthew T; Schulte, Patricia M; Farrell, Anthony P

2013-01-01

Temperature affects processes at all levels of biological organization, but it is unclear whether processes at different levels have similar thermal optima (T(opt)). Here, we compare the T(opt) for aerobic scope, a whole-organism measure of performance, with both the Arrhenius breakpoint temperature for maximum heart rate (HR-ABT), a measure of tissue level performance, and the temperature at which AMP-activated protein kinase (AMPK) is phosphorylated in the heart, an indicator of an increase in dependence on anaerobic energy metabolism at the cellular level in juvenile rainbow trout Oncorhynchus mykiss. The T(opt) for aerobic scope was 19°C, with aerobic scope being maintained at ≥90% of maximum (termed a "T(opt) window") from 16.5° to 20.5°C. HR-ABT occurred at [Formula: see text], while the profile of AMPK phosphorylation started to change from baseline at 19°C, suggesting that these processes have similar thermal sensitivities as a fish is warmed to T(opt). The effects of temperature on AMPK phosphorylation were also measured in coho salmon Oncorhynchus kisutch hearts and compared with previously published values for HR-ABT and aerobic scope T(opt). AMPK phosphorylation in coho hearts began to change at temperatures above 17°C, which again is comparable with the published T(opt) for aerobic scope (17°C) and HR-ABT ([Formula: see text]) in these individuals. Thus, the thermal sensitivity of these subcellular, tissue, and whole-organism functions are highly correlated in both rainbow trout and coho salmon and may depend on each other.

Phospho-mimicking Atf1 mutants bypass the transcription activating function of the MAP kinase Sty1 of fission yeast.

PubMed

Sánchez-Mir, Laura; Salat-Canela, Clàudia; Paulo, Esther; Carmona, Mercè; Ayté, José; Oliva, Baldo; Hidalgo, Elena

2018-02-01

Stress-dependent activation of signaling cascades is often mediated by phosphorylation events, but the exact nature and role of these phosphorelays are frequently poorly understood. Here, we review which are the consequences of the stress-dependent phosphorylation of a transcription factor on gene activation. In fission yeast, the MAP kinase Sty1 is activated upon several environmental hazards and promotes cell adaptation and survival, greatly through activation of a gene program mediated by the transcription factor Atf1. Although described decades ago, the role of the phosphorylation of Atf1 by Sty1 is still a matter of debate. We present here a brief review of recent data, obtained through the characterization of several phosphorylation mutant derivatives of Atf1, demonstrating that Atf1 phosphorylation does not stabilize the factor nor stimulates its binding to DNA. Rather, it provides a structural platform of interaction with the transcriptional machinery. Based on these findings, future work will establish how this phosphorylated trans-activation domain promotes the massive gene expression shift allowing cellular adaptation to stress.

Pan-FGFR inhibition leads to blockade of FGF23 signaling, soft tissue mineralization, and cardiovascular dysfunction.

PubMed

Yanochko, Gina M; Vitsky, Allison; Heyen, Jonathan R; Hirakawa, Brad; Lam, Justine L; May, Jeff; Nichols, Tim; Sace, Frederick; Trajkovic, Dusko; Blasi, Eileen

2013-10-01

The fibroblast growth factor receptors (FGFR) play a major role in angiogenesis and are desirable targets for the development of therapeutics. Groups of Wistar Han rats were dosed orally once daily for 4 days with a small molecule pan-FGFR inhibitor (5mg/kg) or once daily for 6 days with a small molecule MEK inhibitor (3mg/kg). Serum phosphorous and FGF23 levels increased in all rats during the course of the study. Histologically, rats dosed with either drug exhibited multifocal, multiorgan soft tissue mineralization. Expression levels of the sodium phosphate transporter Npt2a and the vitamin D-metabolizing enzymes Cyp24a1 and Cyp27b1 were modulated in kidneys of animals dosed with the pan-FGFR inhibitor. Both inhibitors decreased ERK phosphorylation in the kidneys and inhibited FGF23-induced ERK phosphorylation in vitro in a dose-dependent manner. A separate cardiovascular outcome study was performed to monitor hemodynamics and cardiac structure and function of telemetered rats dosed with either the pan-FGFR inhibitor or MEK inhibitor for 3 days. Both compounds increased blood pressure (~+ 17 mmHg), decreased heart rate (~-75 bpm), and modulated echocardiography parameters. Our data suggest that inhibition of FGFR signaling following administration of either pan-FGFR inhibitor or MEK inhibitor interferes with the FGF23 pathway, predisposing animals to hyperphosphatemia and a tumoral calcinosis-like syndrome in rodents.

Increased leaf angle1, a Raf-like MAPKKK that interacts with a nuclear protein family, regulates mechanical tissue formation in the Lamina joint of rice.

PubMed

Ning, Jing; Zhang, Baocai; Wang, Nili; Zhou, Yihua; Xiong, Lizhong

2011-12-01

Mitogen-activated protein kinase kinase kinases (MAPKKKs), which function at the top level of mitogen-activated protein kinase cascades, are clustered into three groups. However, no Group C Raf-like MAPKKKs have yet been functionally identified. We report here the characterization of a rice (Oryza sativa) mutant, increased leaf angle1 (ila1), resulting from a T-DNA insertion in a Group C MAPKKK gene. The increased leaf angle in ila1 is caused by abnormal vascular bundle formation and cell wall composition in the leaf lamina joint, as distinct from the mechanism observed in brassinosteroid-related mutants. Phosphorylation assays revealed that ILA1 is a functional kinase with Ser/Thr kinase activity. ILA1 is predominantly resident in the nucleus and expressed in the vascular bundles of leaf lamina joints. Yeast two-hybrid screening identified six closely related ILA1 interacting proteins (IIPs) of unknown function. Using representative IIPs, the interaction of ILA1 and IIPs was confirmed in vivo. IIPs were localized in the nucleus and showed transactivation activity. Furthermore, ILA1 could phosphorylate IIP4, indicating that IIPs may be the downstream substrates of ILA1. Microarray analyses of leaf lamina joints provided additional evidence for alterations in mechanical strength in ila1. ILA1 is thus a key factor regulating mechanical tissue formation at the leaf lamina joint.

Mechanical stretching stimulates collagen synthesis via down-regulating SO2/AAT1 pathway

PubMed Central

Liu, Jia; Yu, Wen; Liu, Yan; Chen, Selena; Huang, Yaqian; Li, Xiaohui; Liu, Cuiping; Zhang, Yanqiu; Li, Zhenzhen; Du, Jie; Tang, Chaoshu; Du, Junbao; Jin, Hongfang

2016-01-01

The aim of the study was to investigate the role of endogenous sulfur dioxide (SO2)/ aspartate aminotransferase 1 (AAT1) pathway in stretch-induced excessive collagen expression and its mechanism. The mechanical stretch downregulated SO2/AAT1 pathway and increased collagen I and III protein expression. Importantly, AAT1 overexpression blocked the increase in collagen I and III expression, transforming growth factor-β1 (TGF- β1) expression and phosphorylation of Smad2/3 induced by stretch, but AAT1 knockdown mimicked the increase in collagen I and III expression, TGF- β1 expression and phosphorylation of Smad2/3 induced by stretch. Mechanistically, SB431542, a TGF-β1/Smad2/3 inhibitor, eliminated excessive collagen I and III accumulation induced by AAT1 knockdown, stretch or stretch plus AAT1 knockdown. In a rat model of high pulmonary blood flow-induced pulmonary vascular collagen accumulation, AAT1 expression and SO2 content in lung tissues of rat were reduced in shunt rats with high pulmonary blood flow. Supplement of SO2 derivatives inhibited activation of TGF- β1/Smad2/3 pathway and alleviated the excessive collagen accumulation in lung tissues of shunt rats. The results suggested that deficiency of endogenous SO2/AAT1 pathway mediated mechanical stretch-stimulated abnormal collagen accumulation via TGF-β1/Smad2/3 pathway. PMID:26880260

[Several indicators of tissue oxygen during modeling of extravehicular activity of man].

PubMed

Lan'shina, O E; Loginov, V A; Akinfiev, A V; Kovalenko, E A

1995-01-01

Investigations of tissue oxygen indices during simulation of extravehicular activity (EVA) of cosmonauts demonstrated that breathing pure oxygen at approximately 280 mmHg elevates oxygen tension in capillary blood, and capillary-tissue gradient during physical work. Physical work alone stimulates tissue oxygenation due to, apparently, intensification of the processes of oxidative phosphorylation. The observed shifts in oxygen status reverse significantly within the first 5 min after completion of the experiment.

Phosphorylation acts positively and negatively to regulate MRTF-A subcellular localisation and activity

PubMed Central

Panayiotou, Richard; Miralles, Francesc; Pawlowski, Rafal; Diring, Jessica; Flynn, Helen R; Skehel, Mark; Treisman, Richard

2016-01-01

The myocardin-related transcription factors (MRTF-A and MRTF-B) regulate cytoskeletal genes through their partner transcription factor SRF. The MRTFs bind G-actin, and signal-regulated changes in cellular G-actin concentration control their nuclear accumulation. The MRTFs also undergo Rho- and ERK-dependent phosphorylation, but the function of MRTF phosphorylation, and the elements and signals involved in MRTF-A nuclear export are largely unexplored. We show that Rho-dependent MRTF-A phosphorylation reflects relief from an inhibitory function of nuclear actin. We map multiple sites of serum-induced phosphorylation, most of which are S/T-P motifs and show that S/T-P phosphorylation is required for transcriptional activation. ERK-mediated S98 phosphorylation inhibits assembly of G-actin complexes on the MRTF-A regulatory RPEL domain, promoting nuclear import. In contrast, S33 phosphorylation potentiates the activity of an autonomous Crm1-dependent N-terminal NES, which cooperates with five other NES elements to exclude MRTF-A from the nucleus. Phosphorylation thus plays positive and negative roles in the regulation of MRTF-A. DOI: http://dx.doi.org/10.7554/eLife.15460.001 PMID:27304076

Phosphorylation of Wheat Germ Initiation Factors and Ribosomal Proteins 1

PubMed Central

Browning, Karen S.; Yan, Tyan Fuh J.; Lauer, Stephen J.; Aquino, Lu Ann; Tao, Mariano; Ravel, Joanne M.

1985-01-01

The ability of the wheat germ initiation factors and ribosomes to serve as substrates for a wheat germ protein kinase (Yan and Tao 1982 J Biol Chem 257: 7037-7043) has been investigated. The wheat germ kinase catalyzes the phosphorylation of the 42,000 dalton subunit of eukaryotic initiation factor (eIF)-2 and the 107,000 dalton subunit of eIF-3. Other initiation factors, eIF-4B and eIF-4A, and elongation factors, EF-1 and EF-2, are not phosphorylated by the kinase. Quantitative analysis indicates that the kinase catalyzes the incorporation of about 0.5 to 0.6 mole of phosphate per mole of the 42,000 dalton subunit of eIF-2 and about 6 moles of phosphate per mole of the 107,000 dalton subunit of eIF-3. Three proteins (Mr = 38,000, 14,800, and 12,600) of the 60S ribosomal subunit are phosphorylated by the kinase, but none of the 40S ribosomal proteins are substrates of the kinase. No effects of phosphorylation on the activities of eIF-2, eIF-3, or 60S ribosomal subunits could be demonstrated in vitro. Images Fig. 1 Fig. 3 Fig. 4 PMID:16664060

Phosphorylation of eukaryotic elongation factor 2 (eEF2) by cyclin A-cyclin-dependent kinase 2 regulates its inhibition by eEF2 kinase.

PubMed

Hizli, Asli A; Chi, Yong; Swanger, Jherek; Carter, John H; Liao, Yi; Welcker, Markus; Ryazanov, Alexey G; Clurman, Bruce E

2013-02-01

Protein synthesis is highly regulated via both initiation and elongation. One mechanism that inhibits elongation is phosphorylation of eukaryotic elongation factor 2 (eEF2) on threonine 56 (T56) by eEF2 kinase (eEF2K). T56 phosphorylation inactivates eEF2 and is the only known normal eEF2 functional modification. In contrast, eEF2K undergoes extensive regulatory phosphorylations that allow diverse pathways to impact elongation. We describe a new mode of eEF2 regulation and show that its phosphorylation by cyclin A-cyclin-dependent kinase 2 (CDK2) on a novel site, serine 595 (S595), directly regulates T56 phosphorylation by eEF2K. S595 phosphorylation varies during the cell cycle and is required for efficient T56 phosphorylation in vivo. Importantly, S595 phosphorylation by cyclin A-CDK2 directly stimulates eEF2 T56 phosphorylation by eEF2K in vitro, and we suggest that S595 phosphorylation facilitates T56 phosphorylation by recruiting eEF2K to eEF2. S595 phosphorylation is thus the first known eEF2 modification that regulates its inhibition by eEF2K and provides a novel mechanism linking the cell cycle machinery to translational control. Because all known eEF2 regulation is exerted via eEF2K, S595 phosphorylation may globally couple the cell cycle machinery to regulatory pathways that impact eEF2K activity.

Phosphorylation of Eukaryotic Elongation Factor 2 (eEF2) by Cyclin A–Cyclin-Dependent Kinase 2 Regulates Its Inhibition by eEF2 Kinase

PubMed Central

Hizli, Asli A.; Chi, Yong; Swanger, Jherek; Carter, John H.; Liao, Yi; Welcker, Markus; Ryazanov, Alexey G.

2013-01-01

Protein synthesis is highly regulated via both initiation and elongation. One mechanism that inhibits elongation is phosphorylation of eukaryotic elongation factor 2 (eEF2) on threonine 56 (T56) by eEF2 kinase (eEF2K). T56 phosphorylation inactivates eEF2 and is the only known normal eEF2 functional modification. In contrast, eEF2K undergoes extensive regulatory phosphorylations that allow diverse pathways to impact elongation. We describe a new mode of eEF2 regulation and show that its phosphorylation by cyclin A–cyclin-dependent kinase 2 (CDK2) on a novel site, serine 595 (S595), directly regulates T56 phosphorylation by eEF2K. S595 phosphorylation varies during the cell cycle and is required for efficient T56 phosphorylation in vivo. Importantly, S595 phosphorylation by cyclin A-CDK2 directly stimulates eEF2 T56 phosphorylation by eEF2K in vitro, and we suggest that S595 phosphorylation facilitates T56 phosphorylation by recruiting eEF2K to eEF2. S595 phosphorylation is thus the first known eEF2 modification that regulates its inhibition by eEF2K and provides a novel mechanism linking the cell cycle machinery to translational control. Because all known eEF2 regulation is exerted via eEF2K, S595 phosphorylation may globally couple the cell cycle machinery to regulatory pathways that impact eEF2K activity. PMID:23184662

Increased amount of phosphorylated proinflammatory osteopontin in rheumatoid arthritis synovia is associated to decreased tartrate-resistant acid phosphatase 5B/5A ratio.

PubMed

Luukkonen, Jani; Pascual, Laia Mira; Patlaka, Christina; Lång, Pernilla; Turunen, Sanna; Halleen, Jussi; Nousiainen, Tomi; Valkealahti, Maarit; Tuukkanen, Juha; Andersson, Göran; Lehenkari, Petri

2017-01-01

Osteopontin (OPN) is an immunoregulatory protein which production increases in both rheumatoid arthritis (RA) and osteoarthritis (OA). Phosphorylated osteopontin (Phospho-OPN) is known to increase macrophage and osteoclast activation, this process is controlled by extracellular tartrate-resistant acid phosphatase (TRAcP), also a biomarker for RA. Here, we evaluated the phosphorylation status of OPN in RA and OA synovia, as well as its correlation with TRAcP isoforms. Synovial tissue and fluid were obtained from 24 RA (14 seropositive and 10 seronegative) and 24 OA patients. Western blotting was used to analyze the extent of OPN phosphorylation. TRAcP isoforms were measured in synovial fluid using ELISA; immunohistochemistry assessed the distribution of OPN and TRAcP expressing cells in the synovial tissue, especially distinguishing between the TRAcP isoforms. Full-length OPN was more phosphorylated in RA than in OA (p<0.05). The thrombin cleaved C-terminal end of OPN was also more phosphorylated in RA (p<0.05). RA patients had a lower concentration of TRAcP 5B and higher concentration of less active 5A in their synovial fluid compared to OA patients. The TRAcP 5B/5A ratio was decreased in RA and correlated negatively with the amount of phospho-OPN (p<0.05). TRAcP positive cells for both isoforms were found all along the synovial lining; OPN antibody staining was localized in the extracellular matrix. Our data suggests that in RA the synovial fluid contains insufficient amounts of TRAcP 5B which increase levels of the proinflammatory phospho-OPN. This may lead to increased macrophage and osteoclast activation, resulting in the increased local inflammation and bone resorption present in RA joints.

Antibodies and radioimmunoassays for phosphoserine, phosphothreonine and phosphotyrosine. Serologic specificities and levels of the phosphoamino acids in cytoplasmic fractions of rat tissues.

PubMed

Levine, L; Gjika, H B; Van Vunakis, H

1989-11-30

For antibody production, the O-phosphorylated derivative of tyrosine, threonine, or serine was covalently linked to succinylated bovine albumin via the carbodiimide reaction. Each conjugate was then complexed with methylated bovine albumin for immunization of rabbits. To determine binding, the corresponding O-phosphorylated [3H]amino acids were chemically synthesized. In addition, these 3H-phosphorylated derivatives were acylated (with succinic or acetic anhydride) to obtain ligands whose structures resemble those present in the immunogen. The acylated ligands bound to their respective antibodies more effectively: in some cases binding was about three orders of magnitude greater than their non-acylated counterparts. Radioimmunoassays were therefore developed using the N-succinyl-[3H]phosphoamino acids. When the unlabeled N-succinyl-phosphorylated amino acids were used as inhibitors in the homologous immune systems, 50% displacement of the labeled ligand was found with 0.06, 0.27 or 0.8 pmol of the tyrosine, threonine, or serine derivative, respectively. The antibodies were highly specific for the homologous hapten; the requirement for the phosphate group on the acylated amino acid was essentially absolute. Antibody content (expressed as mg/ml serum) and apparent binding constants for the N-succinyl derivatives in individual bleedings of immune sera were 1.9 and 1 X 10(10) M-1 for phosphotyrosine, 0.825 and 6 X 10(8) M-1 for phosphothreonine, and 0.150 and 2 X 10(8) M-1 for phosphoserine. The radioimmunoassays were used to quantitate the phosphoamino acids in cytoplasmic fractions of rat tissue extracts. The production of antibodies to phosphorylated O-tyrosine has been reported previously, but to our knowledge, this represents the first report of antibodies specific for O-phosphorylated serine and threonine residues.

Effects of a ketogenic diet on adipose tissue, liver, and serum biomarkers in sedentary rats and rats that exercised via resisted voluntary wheel running.

PubMed

Holland, Angelia Maleah; Kephart, Wesley C; Mumford, Petey W; Mobley, Christopher Brooks; Lowery, Ryan P; Shake, Joshua J; Patel, Romil K; Healy, James C; McCullough, Danielle J; Kluess, Heidi A; Huggins, Kevin W; Kavazis, Andreas N; Wilson, Jacob M; Roberts, Michael D

2016-08-01

We investigated the effects of different diets on adipose tissue, liver, serum morphology, and biomarkers in rats that voluntarily exercised. Male Sprague-Dawley rats (∼9-10 wk of age) exercised with resistance-loaded voluntary running wheels (EX; wheels loaded with 20-60% body mass) or remained sedentary (SED) over 6 wk. EX and SED rats were provided isocaloric amounts of either a ketogenic diet (KD; 20.2%-10.3%-69.5% protein-carbohydrate-fat), a Western diet (WD; 15.2%-42.7-42.0%), or standard chow (SC; 24.0%-58.0%-18.0%); n = 8-10 in each diet for SED and EX rats. Following the intervention, body mass and feed efficiency were lowest in KD rats, independent of exercise (P < 0.05). Absolute and relative (body mass-adjusted) omental adipose tissue (OMAT) masses were greatest in WD rats (P < 0.05), and OMAT adipocyte diameters were lowest in KD-fed rats (P < 0.05). None of the assayed OMAT or subcutaneous (SQ) protein markers were affected by the diets [total acetyl coA carboxylase (ACC), CD36, and CEBPα or phosphorylated NF-κB/p65, AMPKα, and hormone-sensitive lipase (HSL)], although EX unexpectedly altered some OMAT markers (i.e., higher ACC and phosphorylated NF-κB/p65, and lower phosphorylated AMPKα and phosphorylated HSL). Liver triglycerides were greatest in WD rats (P < 0.05), and liver phosphorylated NF-κB/p65 was lowest in KD rats (P < 0.05). Serum insulin, glucose, triglycerides, and total cholesterol were greater in WD and/or SC rats compared with KD rats (P < 0.05), and serum β-hydroxybutyrate was greater in KD vs. SC rats (P < 0.05). In conclusion, KD rats presented a healthier metabolic profile, albeit the employed exercise protocol minimally impacts any potentiating effects that KD has on fat loss. Copyright © 2016 the American Physiological Society.

[Systemic and local mechanisms leading to cachexia in cancer].

PubMed

Grabiec, Kamil; Burchert, Marta; Milewska, Marta; Błaszczyk, Maciej; Grzelkowska-Kowalczyk, Katarzyna

2013-12-31

Cachexia is a multifactorial syndrome of atrophy of skeletal muscle and adipose tissue, resulting in progressive loss of body weight associated with low quality of life and poor prognosis in cancer. Studies on experimental animal models and observations on patients have shown that the soluble factors secreted by tumor cells and tissues of the patient can participate in regulation of the wasting process. Cachexia is often accompanied by anorexia, which is caused by predominance of signals inhibiting appetite in the hypothalamus, such as release of proopiomelanocortin and anorexigenic action of proinflammatory cytokines (IL-1α, IL-1β, IL-6, TNF-α). Cachexia is also accompanied by extensive metabolic changes consisting of increase of resting energy expenditure and disturbance of carbohydrate, protein and lipid metabolism. Increased expression of protein uncoupling phosphorylation leads to increased thermogenesis in skeletal muscle. Tumor tissue hypoxia caused by its growth beyond blood vessels activates the transcription factor HIF-1, which results in increase in glycolysis, and leads to lactic acid accumulation and activation of the energy inefficient Cori cycle. Loss of fat tissue is caused by increase of lipolysis induced by lipid-mobilizing factor (LMF) and proinflammatory cytokines. Skeletal muscle wasting in cachexia is caused by a reduction of protein synthesis at the stage of initiation and elongation of translation and the simultaneous increase of protein degradation via ubiquitin-dependent and lysosomal pathways. The main mediators of skeletal muscle wasting in cancer are proteolysis-inducing factor (PIF), proinflammatory cytokines, and angiotensin II acting through increased levels of reactive oxygen species (ROS) and nuclear factor NF-κB activation, as well as glucocorticoid activated FOXO transcription factors and myostatin. Understanding of the complexity of the interaction of factors produced by the tumor and the patient's body may form the basis for the development of effective treatments for cachexia in cancer and other pathological conditions.

Evaluation of several two-dimensional gel electrophoresis techniques in cardiac proteomics.

PubMed

Li, Zhao Bo; Flint, Paul W; Boluyt, Marvin O

2005-09-01

Two-dimensional gel electrophoresis (2-DE) is currently the best method for separating complex mixtures of proteins, and its use is gradually becoming more common in cardiac proteome analysis. A number of variations in basic 2-DE have emerged, but their usefulness in analyzing cardiac tissue has not been evaluated. The purpose of the present study was to systematically evaluate the capabilities and limitations of several 2-DE techniques for separating proteins from rat heart tissue. Immobilized pH gradient strips of various pH ranges, parameters of protein loading and staining, subcellular fractionation, and detection of phosphorylated proteins were studied. The results provide guidance for proteome analysis of cardiac and other tissues in terms of selection of the isoelectric point separating window for cardiac proteins, accurate quantitation of cardiac protein abundance, stabilization of technical variation, reduction of sample complexity, enrichment of low-abundant proteins, and detection of phosphorylated proteins.

Integration of actomyosin contractility with cell-cell adhesion during dorsal closure.

PubMed

Duque, Julia; Gorfinkiel, Nicole

2016-12-15

In this work, we combine genetic perturbation, time-lapse imaging and quantitative image analysis to investigate how pulsatile actomyosin contractility drives cell oscillations, apical cell contraction and tissue closure during morphogenesis of the amnioserosa, the main force-generating tissue during the dorsal closure in Drosophila We show that Myosin activity determines the oscillatory and contractile behaviour of amnioserosa cells. Reducing Myosin activity prevents cell shape oscillations and reduces cell contractility. By contrast, increasing Myosin activity increases the amplitude of cell shape oscillations and the time cells spend in the contracted phase relative to the expanded phase during an oscillatory cycle, promoting cell contractility and tissue closure. Furthermore, we show that in AS cells, Rok controls Myosin foci formation and Mbs regulates not only Myosin phosphorylation but also adhesion dynamics through control of Moesin phosphorylation, showing that Mbs coordinates actomyosin contractility with cell-cell adhesion during amnioserosa morphogenesis. © 2016. Published by The Company of Biologists Ltd.

Recombinant human GLP-1(rhGLP-1) alleviating renal tubulointestitial injury in diabetic STZ-induced rats.

PubMed

Yin, Weiqin; Xu, Shiqing; Wang, Zai; Liu, Honglin; Peng, Liang; Fang, Qing; Deng, Tingting; Zhang, Wenjian; Lou, Jinning

2018-01-01

GLP-1-based treatment improves glycemia through stimulation of insulin secretion and inhibition of glucagon secretion. Recently, more and more findings showed that GLP-1 could also protect kidney from diabetic nephropathy. Most of these studies focused on glomeruli, but the effect of GLP-1 on tubulointerstitial and tubule is not clear yet. In this study, we examined the renoprotective effect of recombinant human GLP-1 (rhGLP-1), and investigated the influence of GLP-1 on inflammation and tubulointerstitial injury using diabetic nephropathy rats model of STZ-induced. The results showed that rhGLP-1 reduced urinary albumin without influencing the body weight and food intake. rhGLP-1 could increased the serum C-peptide slightly but not lower fasting blood glucose significantly. In diabetic nephropathy rats, beside glomerular sclerosis, tubulointerstitial fibrosis was very serious. These lesions could be alleviated by rhGLP-1. rhGLP-1 decreased the expression of profibrotic factors collagen I, α-SMA, fibronectin, and inflammation factors MCP-1 and TNFα in tubular tissue and human proximal tubular cells (HK-2 cells). Furthermore, rhGLP-1 significantly inhibited the phosphorylation of NF-κB, MAPK in both diabetic tubular tissue and HK-2 cells. The inhibition of the expression of TNFα, MCP-1, collagen I and α-SMA in HK-2 cells by GLP-1 could be mimicked by blocking NF-κB or MAPK. These results indicate that rhGLP-1 exhibit renoprotective effect by alleviation of tubulointerstitial injury via inhibiting phosphorylation of MAPK and NF-κB. Therefore, rhGLP-1 may be a potential drug for treatment of diabetic nephropathy. Copyright © 2017 Elsevier Inc. All rights reserved.

Leukemia inhibitory factor promotes human first trimester extravillous trophoblast adhesion to extracellular matrix and secretion of tissue inhibitor of metalloproteinases-1 and -2

PubMed Central

Tapia, Alejandro; Salamonsen, Lois A.; Manuelpillai, Ursula; Dimitriadis, Evdokia

2008-01-01

BACKGROUND Leukemia inhibitory factor (LIF) is a pleiotropic cytokine that is essential for blastocyst implantation in mice. It has been suggested that LIF may play a role in human first trimester extravillous trophoblast (EVT) invasion. The aim of the present study was to establish whether LIF induces changes in EVT function related to invasiveness. METHODS Primary first trimester human EVT cell cultures were treated with/without LIF and the effects on cell adhesion to fibronectin (FN), vitronectin (VN) and laminin (LN) were assessed. Transcript levels of integrin subunits that mediate cell adhesion to these extracellular matrix (ECM) elements were determined by real-time RT–PCR. Matrix metalloproteinase (MMP)2 and MMP9 secretion was assessed by gelatine zymography and tissue inhibitors matrix metalloproteinase (TIMP) -1 and TIMP-2 secretion by enzyme-linked immunosorbent assay. RESULTS EVT cells showed increased adhesion to FN, VN and LN ECM elements in response to LIF (20, 20 and 29%, respectively, P < 0.05 FN and VN compared to control; and P < 0.001 LN compared to control). Integrin β4 mRNA levels decreased by 50% following LIF treatment (P < 0.001 versus control). MMP2 and MMP9 secretion was not affected by LIF but LIF did increase secretion of TIMP-1 and -2 (P < 0.001 versus control). LIF stimulated the phosphorylation of signal transducer and activator of transcription (STAT) 3 protein while it did not affect STAT3 protein abundance. The addition of a LIF inhibitor attenuated the LIF-induced STAT3 phosphorylation in EVT. CONCLUSION The results suggest that LIF can regulate EVT invasion, suggesting an important role in early placental development. PMID:18492704

Obesity, Oxidative Stress, Adipose Tissue Dysfunction, and the Associated Health Risks: Causes and Therapeutic Strategies.

PubMed

Manna, Prasenjit; Jain, Sushil K

2015-12-01

Obesity is gaining acceptance as a serious primary health burden that impairs the quality of life because of its associated complications, including diabetes, cardiovascular diseases, cancer, asthma, sleep disorders, hepatic dysfunction, renal dysfunction, and infertility. It is a complex metabolic disorder with a multifactorial origin. Growing evidence suggests that oxidative stress plays a role as the critical factor linking obesity with its associated complications. Obesity per se can induce systemic oxidative stress through various biochemical mechanisms, such as superoxide generation from NADPH oxidases, oxidative phosphorylation, glyceraldehyde auto-oxidation, protein kinase C activation, and polyol and hexosamine pathways. Other factors that also contribute to oxidative stress in obesity include hyperleptinemia, low antioxidant defense, chronic inflammation, and postprandial reactive oxygen species generation. In addition, recent studies suggest that adipose tissue plays a critical role in regulating the pathophysiological mechanisms of obesity and its related co-morbidities. To establish an adequate platform for the prevention of obesity and its associated health risks, understanding the factors that contribute to the cause of obesity is necessary. The most current list of obesity determinants includes genetic factors, dietary intake, physical activity, environmental and socioeconomic factors, eating disorders, and societal influences. On the basis of the currently identified predominant determinants of obesity, a broad range of strategies have been recommended to reduce the prevalence of obesity, such as regular physical activity, ad libitum food intake limiting to certain micronutrients, increased dietary intake of fruits and vegetables, and meal replacements. This review aims to highlight recent findings regarding the role of oxidative stress in the pathogenesis of obesity and its associated risk factors, the role of dysfunctional adipose tissue in development of these risk factors, and potential strategies to regulate body weight loss/gain for better health benefits.

Obesity, Oxidative Stress, Adipose Tissue Dysfunction, and the Associated Health Risks: Causes and Therapeutic Strategies

PubMed Central

Manna, Prasenjit

2015-01-01

Abstract Obesity is gaining acceptance as a serious primary health burden that impairs the quality of life because of its associated complications, including diabetes, cardiovascular diseases, cancer, asthma, sleep disorders, hepatic dysfunction, renal dysfunction, and infertility. It is a complex metabolic disorder with a multifactorial origin. Growing evidence suggests that oxidative stress plays a role as the critical factor linking obesity with its associated complications. Obesity per se can induce systemic oxidative stress through various biochemical mechanisms, such as superoxide generation from NADPH oxidases, oxidative phosphorylation, glyceraldehyde auto-oxidation, protein kinase C activation, and polyol and hexosamine pathways. Other factors that also contribute to oxidative stress in obesity include hyperleptinemia, low antioxidant defense, chronic inflammation, and postprandial reactive oxygen species generation. In addition, recent studies suggest that adipose tissue plays a critical role in regulating the pathophysiological mechanisms of obesity and its related co-morbidities. To establish an adequate platform for the prevention of obesity and its associated health risks, understanding the factors that contribute to the cause of obesity is necessary. The most current list of obesity determinants includes genetic factors, dietary intake, physical activity, environmental and socioeconomic factors, eating disorders, and societal influences. On the basis of the currently identified predominant determinants of obesity, a broad range of strategies have been recommended to reduce the prevalence of obesity, such as regular physical activity, ad libitum food intake limiting to certain micronutrients, increased dietary intake of fruits and vegetables, and meal replacements. This review aims to highlight recent findings regarding the role of oxidative stress in the pathogenesis of obesity and its associated risk factors, the role of dysfunctional adipose tissue in development of these risk factors, and potential strategies to regulate body weight loss/gain for better health benefits. PMID:26569333

PhosphoregDB: The tissue and sub-cellular distribution of mammalian protein kinases and phosphatases

PubMed Central

Forrest, Alistair RR; Taylor, Darrin F; Fink, J Lynn; Gongora, M Milena; Flegg, Cameron; Teasdale, Rohan D; Suzuki, Harukazu; Kanamori, Mutsumi; Kai, Chikatoshi; Hayashizaki, Yoshihide; Grimmond, Sean M

2006-01-01

Background Protein kinases and protein phosphatases are the fundamental components of phosphorylation dependent protein regulatory systems. We have created a database for the protein kinase-like and phosphatase-like loci of mouse that integrates protein sequence, interaction, classification and pathway information with the results of a systematic screen of their sub-cellular localization and tissue specific expression data mined from the GNF tissue atlas of mouse. Results The database lets users query where a specific kinase or phosphatase is expressed at both the tissue and sub-cellular levels. Similarly the interface allows the user to query by tissue, pathway or sub-cellular localization, to reveal which components are co-expressed or co-localized. A review of their expression reveals 30% of these components are detected in all tissues tested while 70% show some level of tissue restriction. Hierarchical clustering of the expression data reveals that expression of these genes can be used to separate the samples into tissues of related lineage, including 3 larger clusters of nervous tissue, developing embryo and cells of the immune system. By overlaying the expression, sub-cellular localization and classification data we examine correlations between class, specificity and tissue restriction and show that tyrosine kinases are more generally expressed in fewer tissues than serine/threonine kinases. Conclusion Together these data demonstrate that cell type specific systems exist to regulate protein phosphorylation and that for accurate modelling and for determination of enzyme substrate relationships the co-location of components needs to be considered. PMID:16504016

Effect of Peroral Administration of Chromium on Insulin Signaling Pathway in Skeletal Muscle Tissue of Holstein Calves.

PubMed

Jovanović, Ljubomir; Pantelić, Marija; Prodanović, Radiša; Vujanac, Ivan; Đurić, Miloje; Tepavčević, Snežana; Vranješ-Đurić, Sanja; Korićanac, Goran; Kirovski, Danijela

2017-12-01

The objective of this study was to investigate the effects of peroral administration of chromium-enriched yeast on glucose tolerance in Holstein calves, assessed by insulin signaling pathway molecule determination and intravenous glucose tolerance test (IVGTT). Twenty-four Holstein calves, aged 1 month, were chosen for the study and divided into two groups: the PoCr group (n = 12) that perorally received 0.04 mg of Cr/kg of body mass daily, for 70 days, and the NCr group (n = 12) that received no chromium supplementation. Skeletal tissue samples from each calf were obtained on day 0 and day 70 of the experiment. Chromium supplementation increased protein content of the insulin β-subunit receptor, phosphorylation of insulin receptor substrate 1 at Tyrosine 632, phosphorylation of Akt at Serine 473, glucose transporter-4, and AMP-activated protein kinase in skeletal muscle tissue, while phosphorylation of insulin receptor substrate 1 at Serine 307 was not affected by chromium treatment. Results obtained during IVGTT, which was conducted on days 0, 30, 50, and 70, suggested an increased insulin sensitivity and, consequently, a better utilization of glucose in the PoCr group. Lower basal concentrations of glucose and insulin in the PoCr group on days 30 and 70 were also obtained. Our results indicate that chromium supplementation improves glucose utilization in calves by enhancing insulin intracellular signaling in the skeletal muscle tissue.

EF24 Suppresses Invasion and Migration of Hepatocellular Carcinoma Cells In Vitro via Inhibiting the Phosphorylation of Src

PubMed Central

Tin, Lamtin; Wu, Yiqi; Jin, Yinji; Jin, Xiaoming; Zhang, Fengmin

2016-01-01

Diphenyl difluoroketone (EF24), a curcumin analog, is a promising anticancer compound that exerts its effects by inhibiting cell proliferation and inducing apoptosis. However, the efficacy of EF24 against cancer metastasis, particularly in hepatocellular carcinoma (HCC), remains elusive. In this study, the effect of EF24 on HCCLM-3 and HepG2 cell migration and invasion was detected by wound healing and transwell assay, respectively. The results revealed that EF24 suppressed the migration and invasion of both HCCLM-3 and HepG2 cells. Furthermore, EF24 treatment decreased the formation of filopodia on the cell surface and inhibited the phosphorylation of Src in both cell lines, which may help contribute towards understanding the mechanism underlying the suppressive effect of EF24 on HCC migration and invasion. Additionally, the expression of total- and phosphorylated-Src in primary HCC tissues and their paired lymph node metastatic tissues was detected, and phosphorylated-Src was found to be associated with HCC lymph node metastasis. The results of this study suggest that Src is a novel and promising therapeutic target in HCC and provide evidence to support the hypothesis that EF24 may be a useful therapeutic agent for the treatment of HCC. PMID:27999817

EF24 Suppresses Invasion and Migration of Hepatocellular Carcinoma Cells In Vitro via Inhibiting the Phosphorylation of Src.

PubMed

Zhao, Ran; Tin, Lamtin; Zhang, Yuhua; Wu, Yiqi; Jin, Yinji; Jin, Xiaoming; Zhang, Fengmin; Li, Xiaobo

2016-01-01

Diphenyl difluoroketone (EF24), a curcumin analog, is a promising anticancer compound that exerts its effects by inhibiting cell proliferation and inducing apoptosis. However, the efficacy of EF24 against cancer metastasis, particularly in hepatocellular carcinoma (HCC), remains elusive. In this study, the effect of EF24 on HCCLM-3 and HepG2 cell migration and invasion was detected by wound healing and transwell assay, respectively. The results revealed that EF24 suppressed the migration and invasion of both HCCLM-3 and HepG2 cells. Furthermore, EF24 treatment decreased the formation of filopodia on the cell surface and inhibited the phosphorylation of Src in both cell lines, which may help contribute towards understanding the mechanism underlying the suppressive effect of EF24 on HCC migration and invasion. Additionally, the expression of total- and phosphorylated-Src in primary HCC tissues and their paired lymph node metastatic tissues was detected, and phosphorylated-Src was found to be associated with HCC lymph node metastasis. The results of this study suggest that Src is a novel and promising therapeutic target in HCC and provide evidence to support the hypothesis that EF24 may be a useful therapeutic agent for the treatment of HCC.

PDSM, a motif for phosphorylation-dependent SUMO modification

PubMed Central

Hietakangas, Ville; Anckar, Julius; Blomster, Henri A.; Fujimoto, Mitsuaki; Palvimo, Jorma J.; Nakai, Akira; Sistonen, Lea

2006-01-01

SUMO (small ubiquitin-like modifier) modification regulates many cellular processes, including transcription. Although sumoylation often occurs on specific lysines within the consensus tetrapeptide ΨKxE, other modifications, such as phosphorylation, may regulate the sumoylation of a substrate. We have discovered PDSM (phosphorylation-dependent sumoylation motif), composed of a SUMO consensus site and an adjacent proline-directed phosphorylation site (ΨKxExxSP). The highly conserved motif regulates phosphorylation-dependent sumoylation of multiple substrates, such as heat-shock factors (HSFs), GATA-1, and myocyte enhancer factor 2. In fact, the majority of the PDSM-containing proteins are transcriptional regulators. Within the HSF family, PDSM is conserved between two functionally distinct members, HSF1 and HSF4b, whose transactivation capacities are repressed through the phosphorylation-dependent sumoylation. As the first recurrent sumoylation determinant beyond the consensus tetrapeptide, the PDSM provides a valuable tool in predicting new SUMO substrates. PMID:16371476

Expression of caveolin in trabecular meshwork cells and its possible implication in pathogenesis of primary open angle glaucoma

PubMed Central

Surgucheva, Irina

2011-01-01

Purpose Primary open-angle glaucoma (POAG), which is the most common form of glaucoma, has been associated with a heterogeneous genetic component. A genome-wide association study has identified a common sequence variant at 7q31 (rs4236601 [A]) near the caveolin genes in patients with POAG. Caveolins are a family of integral membrane proteins which participate in many cellular processes, including vesicular transport, cholesterol homeostasis, signal transduction, cell adhesion and migration. The goal of this study was to investigate the expression and regulation of caveolin 1 (CAV-1) and caveolin 2 (CAV-2) in normal and glaucoma trabecular meshwork (TM) cells. Methods CAV-1 and CAV-2 protein expression was quantified by immunoblot analysis using lysates isolated from primary and immortalized TM cells or TM tissue dissected from normal and POAG eyes. The localization of caveolins in TM cells was assessed by immunofluorescent microscopy. CAV-1 and CAV-2 protein expression was also investigated in TM cells at various time points after subjecting the cells to known glaucomatous insults like dexamethasone (DEX) and tumor growth factor beta2 (TGF-β2) treatment. Phosphorylation of CAV-1 at tyrosine 14 in normal and glaucoma TM cell lines was evaluated using a specific monoclonal antibody (Ab). The 5′ upstream region of the CAV-1 gene was amplified and the sequence variant rs4236601 (A/G polymorphic site) and several putative transcription factor-binding sites were modified by in vitro mutagenesis. The effect of nucleotide sequence modifications in the CAV-1 upstream region on gene expression was assayed in a luciferase-based system in TM and non-TM cells. Results CAV-1 and CAV-2 are expressed in TM cells, with localization to the cytoplasm and perinuclear region. DEX increased CAV-1 expression in immortalized glaucoma TM cells by 2.8±0.1 (n=3) fold at 24 h and 2.5±0.1 (n=3) fold at 48 h, compared to 1.3±0.06 (n=3) fold at 24 and 48 h in immortalized normal TM cells. Phosphorylation of CAV-1 at Tyr14 was reduced by 3.2±0.15 (n=3) fold in glaucomatous TM cells when compared to normal TM cells. In POAG and normal TM tissue, CAV-1 expression was found to be uniform. CAV-2, on the other hand, was variable in independent normal and glaucoma TM tissue. Substitution of a G for an A at base pair −2,388 upstream of the start codon of CAV-1, corresponding to the minor allele rs4236601 [A], increased transcriptional activity in TM and non-TM cells when compared to the native sequence. Deletion analysis of putative transcription factor binding sites in the CAV-1 promoter region caused cell-specific effects on gene expression. Conclusions CAV-1 and CAV-2 are expressed in normal and glaucoma tissue and TM cell lines. Phosphorylation of Tyr14 in CAV-1 and transcriptional regulation of CAV-1 expression may have a role in glaucomatous alterations in TM cells. PMID:22128235

Unprecedented Abundance of Protein Tyrosine Phosphorylation Modulates Shigella flexneri Virulence.

PubMed

Standish, Alistair James; Teh, Min Yan; Tran, Elizabeth Ngoc Hoa; Doyle, Matthew Thomas; Baker, Paul J; Morona, Renato

2016-10-09

Evidence is accumulating that protein tyrosine phosphorylation plays a crucial role in the ability of important human bacterial pathogens to cause disease. While most works have concentrated on its role in the regulation of a major bacterial virulence factor, the polysaccharide capsule, recent studies have suggested a much broader role for this post-translational modification. This prompted us to investigate protein tyrosine phosphorylation in the human pathogen Shigella flexneri. We first completed a tyrosine phosphoproteome, identifying 905 unique tyrosine phosphorylation sites on at least 573 proteins (approximately 15% of all proteins). This is the most tyrosine-phosphorylated sites and proteins in a single bacterium identified to date, substantially more than the level seen in eukaryotic cells. Most had not previously been identified and included proteins encoded by the virulence plasmid, which is essential for S. flexneri to invade cells and cause disease. In order to investigate the function of these phosphorylation sites in important virulence factors, phosphomimetic and ablative mutations were constructed in the type 3 secretion system ATPase Spa47 and the master virulence regulator VirB. This revealed that tyrosine residues phosphorylated in our study are critical for Spa47 and VirB activity, and tyrosine phosphorylation likely regulates their functional activity and subsequently the virulence of this major human pathogen. This study suggests that tyrosine phosphorylation plays a critical role in regulating a wide variety of virulence factors in the human pathogen S. flexneri and serves as a base for future studies defining its complete role. Copyright © 2016 Elsevier Ltd. All rights reserved.

Factor Xa Inhibitor Suppresses the Release of Phosphorylated HSP27 from Collagen-Stimulated Human Platelets: Inhibition of HSP27 Phosphorylation via p44/p42 MAP Kinase

PubMed Central

Tsujimoto, Masanori; Kuroyanagi, Gen; Matsushima-Nishiwaki, Rie; Kito, Yuko; Enomoto, Yukiko; Iida, Hiroki; Ogura, Shinji; Otsuka, Takanobu; Tokuda, Haruhiko; Kozawa, Osamu; Iwama, Toru

2016-01-01

Selective inhibitors of factor Xa (FXa) are widely recognized as useful therapeutic tools for stroke prevention in non-valvular atrial fibrillation or venous thrombosis. Thrombin, which is rapidly generated from pro-thrombin through the activation of factor X to FXa, acts as a potent activator of human platelets. Thus, the reduction of thrombin generation by FXa inhibitor eventually causes a suppressive effect on platelet aggregation. However, little is known whether FXa inhibitors directly affect the function of human platelets. We have previously reported that collagen induces the phosphorylation of heat shock protein 27 (HSP27), a low-molecular weight heat shock protein via Rac-dependent activation of p44/p42 mitogen-activated protein (MAP) kinase in human platelets, eventually resulting in the release of HSP27. In the present study, we investigated the direct effect of FXa inhibitor on the collagen-induced human platelet activation. Rivaroxaban as well as edoxaban significantly reduced the collagen-induced phosphorylation of both HSP27 and p44/p42 MAP kinase without affecting the platelet aggregation. Rivaroxaban significantly inhibited the release of phosphorylated HSP27 from collagen-stimulated platelets but not the secretion of platelet derived growth factor-AB. In patients administrated with rivaroxaban, the collagen-induced levels of phosphorylated HSP27 were markedly diminished after 2 days of administration, which failed to affect the platelet aggregation. These results strongly suggest that FXa inhibitor reduces the collagen-stimulated release of phosphorylated HSP27 from human platelets due to the inhibition of HSP27 phosphorylation via p44/p42 MAP kinase. PMID:26867010

Factor Xa Inhibitor Suppresses the Release of Phosphorylated HSP27 from Collagen-Stimulated Human Platelets: Inhibition of HSP27 Phosphorylation via p44/p42 MAP Kinase.

PubMed

Tsujimoto, Masanori; Kuroyanagi, Gen; Matsushima-Nishiwaki, Rie; Kito, Yuko; Enomoto, Yukiko; Iida, Hiroki; Ogura, Shinji; Otsuka, Takanobu; Tokuda, Haruhiko; Kozawa, Osamu; Iwama, Toru

2016-01-01

Selective inhibitors of factor Xa (FXa) are widely recognized as useful therapeutic tools for stroke prevention in non-valvular atrial fibrillation or venous thrombosis. Thrombin, which is rapidly generated from pro-thrombin through the activation of factor X to FXa, acts as a potent activator of human platelets. Thus, the reduction of thrombin generation by FXa inhibitor eventually causes a suppressive effect on platelet aggregation. However, little is known whether FXa inhibitors directly affect the function of human platelets. We have previously reported that collagen induces the phosphorylation of heat shock protein 27 (HSP27), a low-molecular weight heat shock protein via Rac-dependent activation of p44/p42 mitogen-activated protein (MAP) kinase in human platelets, eventually resulting in the release of HSP27. In the present study, we investigated the direct effect of FXa inhibitor on the collagen-induced human platelet activation. Rivaroxaban as well as edoxaban significantly reduced the collagen-induced phosphorylation of both HSP27 and p44/p42 MAP kinase without affecting the platelet aggregation. Rivaroxaban significantly inhibited the release of phosphorylated HSP27 from collagen-stimulated platelets but not the secretion of platelet derived growth factor-AB. In patients administrated with rivaroxaban, the collagen-induced levels of phosphorylated HSP27 were markedly diminished after 2 days of administration, which failed to affect the platelet aggregation. These results strongly suggest that FXa inhibitor reduces the collagen-stimulated release of phosphorylated HSP27 from human platelets due to the inhibition of HSP27 phosphorylation via p44/p42 MAP kinase.

Pirfenidone inhibits p38-mediated generation of procoagulant microparticles by human alveolar epithelial cells.

PubMed

Neri, Tommaso; Lombardi, Stefania; Faìta, Francesca; Petrini, Silvia; Balìa, Cristina; Scalise, Valentina; Pedrinelli, Roberto; Paggiaro, Pierluigi; Celi, Alessandro

2016-08-01

Pirfenidone is a drug recently approved for idiopathic pulmonary fibrosis but its mechanisms of action are partially unknown. We have previously demonstrated that the airways of patients with idiopathic pulmonary fibrosis contain procoagulant microparticles that activate coagulation factor X to its active form, Xa, a proteinase that signals fibroblast growth and differentiation, thus potentially contributing to the pathogenesis of the disease. We also reported that in vitro exposure of human alveolar cells to H2O2 causes microparticle generation. Since p38 activation is involved in microparticle generation in some cell models and p38 inhibition is one of the mechanisms of action of pirfenidone, we investigated the hypothesis that H2O2-induced generation of microparticles by alveolar cells is dependent on p38 phosphorylation and is inhibited by pirfenidone. H2O2 stimulation of alveolar cells caused p38 phosphorylation that was inhibited by pirfenidone. The drug also inhibited H2O2 induced microparticle generation as assessed by two independent methods (solid phase thrombin generation and flow cytometry). The shedding of microparticle-bound tissue factor activity was also inhibited by pirfenidone. Inhibition of p38-mediated generation of procoagulant microparticle is a previously unrecognized mechanism of action of the antifibrotic drug, pirfenidone. Copyright © 2016 Elsevier Ltd. All rights reserved.

Gravity loading induces adenosine triphosphate release and phosphorylation of extracellular signal-regulated kinases in human periodontal ligament cells.

PubMed

Ito, Mai; Arakawa, Toshiya; Okayama, Miki; Shitara, Akiko; Mizoguchi, Itaru; Takuma, Taishin

2014-11-01

The periodontal ligament (PDL) receives mechanical stress (MS) from dental occlusion or orthodontic tooth movement. Mechanical stress is thought to be a trigger for remodeling of the PDL and alveolar bone, although its signaling mechanism is still unclear. So we investigated the effect of MS on adenosine triphosphate (ATP) release and extracellular signal-regulated kinases (ERK) phosphorylation in PDL cells. Mechanical stress was applied to human PDL cells as centrifugation-mediated gravity loading. Apyrase, Ca(2+)-free medium and purinergic receptor agonists and antagonists were utilized to analyze the contribution of purinergic receptors to ERK phosphorylation. Gravity loading and ATP increased ERK phosphorylation by 5 and 2.5 times, respectively. Gravity loading induced ATP release from PDL cells by tenfold. Apyrase and suramin diminished ERK phosphorylation induced by both gravity loading and ATP. Under Ca(2+)-free conditions the phosphorylation by gravity loading was partially decreased, whereas ATP-induced phosphorylation was unaffected. Receptors P2Y4 and P2Y6 were prominently expressed in the PDL cells. Gravity loading induced ATP release and ERK phosphorylation in PDL fibroblasts, and ATP signaling via P2Y receptors was partially involved in this phosphorylation, which in turn would enhance gene expression for the remodeling of PDL tissue during orthodontic tooth movement. © 2013 Wiley Publishing Asia Pty Ltd.

Phosphorylation of insulin receptor substrate-1 serine 307 correlates with JNK activity in atrophic skeletal muscle

NASA Technical Reports Server (NTRS)

Hilder, Thomas L.; Tou, Janet C L.; Grindeland, Richard E.; Wade, Charles E.; Graves, Lee M.

2003-01-01

c-Jun NH(2)-terminal kinase (JNK) has been shown to negatively regulate insulin signaling through serine phosphorylation of residue 307 within the insulin receptor substrate-1 (IRS-1) in adipose and liver tissue. Using a rat hindlimb suspension model for muscle disuse atrophy, we found that JNK activity was significantly elevated in atrophic soleus muscle and that IRS-1 was phosphorylated on Ser(307) prior to the degradation of the IRS-1 protein. Moreover, we observed a corresponding reduction in Akt activity, providing biochemical evidence for the development of insulin resistance in atrophic skeletal muscle.

Phospho-mimicry mutant of atToc33 affects early development of Arabidopsis thaliana.

PubMed

Oreb, Mislav; Zoryan, Mikael; Vojta, Aleksandar; Maier, Uwe G; Eichacker, Lutz A; Schleiff, Enrico

2007-12-22

The precursor protein receptor at the chloroplast outer membrane atToc33 is a GTPase, which can be inactivated by phosphorylation in vitro, being arrested in the GDP loaded state. To assess the physiological function of phosphorylation, attoc33 knock out mutants were complemented with a mutated construct mimicking the constitutively phosphorylated state. Our data suggest that the reduced functionality of the mutant protein can be compensated by its upregulation. Chloroplast biogenesis and photosynthetic activity are impaired in the mutants during the early developmental stage, which is consistent with the requirement of atToc33 in young photosynthetic tissues.

Phosphorylation of translation factors in response to anoxia in turtles, Trachemys scripta elegans: role of the AMP-activated protein kinase and target of rapamycin signalling pathways.

PubMed

Rider, Mark H; Hussain, Nusrat; Dilworth, Stephen M; Storey, Kenneth B

2009-12-01

Long-term survival of oxygen deprivation by animals with well-developed anoxia tolerance depends on multiple biochemical adaptations including strong metabolic rate depression. We investigated whether the AMP-activated protein kinase (AMPK) could play a regulatory role in the suppression of protein synthesis that occurs when turtles experience anoxic conditions. AMPK activity and the phosphorylation state of ribosomal translation factors were measured in liver, heart, red muscle and white muscle of red-eared slider turtles (Trachemys scripta elegans) subjected to 20 h of anoxic submergence. AMPK activity increased twofold in white muscle of anoxic turtles compared with aerobic controls but remained unchanged in liver and red muscle, whereas in heart AMPK activity decreased by 40%. Immunoblotting with phospho-specific antibodies revealed that eukaryotic elongation factor-2 phosphorylation at the inactivating Thr56 site increased six- and eightfold in red and white muscles from anoxic animals, respectively, but was unchanged in liver and heart. The phosphorylation state of the activating Thr389 site of p70 ribosomal protein S6 kinase was reduced under anoxia in red muscle and heart but was unaffected in liver and white muscle. Exposure to anoxia decreased 40S ribosomal protein S6 phosphorylation in heart and promoted eukaryotic initiation factor 4E-binding protein-1 (4E-BP1) dephosphorylation in red muscle, but surprisingly increased 4E-BP1 phosphorylation in white muscle. The changes in phosphorylation state of translation factors suggest that organ-specific patterns of signalling and response are involved in achieving the anoxia-induced suppression of protein synthesis in turtles.

Phosphorylation of glutaminase by PKCε is essential for its enzymatic activity and critically contributes to tumorigenesis.

PubMed

Han, Tianyu; Zhan, Weihua; Gan, Mingxi; Liu, Fanrong; Yu, Bentong; Chin, Y Eugene; Wang, Jian-Bin

2018-06-01

Glutamine metabolism plays an important role in cancer development and progression. Glutaminase C (GAC), the first enzyme in glutaminolysis, has emerged as an important target for cancer therapy and many studies have focused on the mechanism of enhanced GAC expression in cancer cells. However, little is known about the post-translational modification of GAC. Here, we report that phosphorylation is a crucial post-translational modification of GAC, which is responsible for the higher glutaminase activity in lung tumor tissues and cancer cells. We identify the key Ser314 phosphorylation site on GAC that is regulated by the NF-κB-PKCε axis. Blocking Ser314 phosphorylation by the S314A mutation in lung cancer cells inhibits the glutaminase activity, triggers genetic reprogramming, and alleviates tumor malignancy. Furthermore, we find that a high level of GAC phosphorylation correlates with poor survival rate of lung cancer patients. These findings highlight a previously unappreciated mechanism for activation of GAC by phosphorylation and demonstrate that targeting glutaminase activity can inhibit oncogenic transformation.

An MRM-based workflow for quantifying cardiac mitochondrial protein phosphorylation in murine and human tissue.

PubMed

Lam, Maggie P Y; Scruggs, Sarah B; Kim, Tae-Young; Zong, Chenggong; Lau, Edward; Wang, Ding; Ryan, Christopher M; Faull, Kym F; Ping, Peipei

2012-08-03

The regulation of mitochondrial function is essential for cardiomyocyte adaptation to cellular stress. While it has long been understood that phosphorylation regulates flux through metabolic pathways, novel phosphorylation sites are continually being discovered in all functionally distinct areas of the mitochondrial proteome. Extracting biologically meaningful information from these phosphorylation sites requires an adaptable, sensitive, specific and robust method for their quantification. Here we report a multiple reaction monitoring-based mass spectrometric workflow for quantifying site-specific phosphorylation of mitochondrial proteins. Specifically, chromatographic and mass spectrometric conditions for 68 transitions derived from 23 murine and human phosphopeptides, and their corresponding unmodified peptides, were optimized. These methods enabled the quantification of endogenous phosphopeptides from the outer mitochondrial membrane protein VDAC, and the inner membrane proteins ANT and ETC complexes I, III and V. The development of this quantitative workflow is a pivotal step for advancing our knowledge and understanding of the regulatory effects of mitochondrial protein phosphorylation in cardiac physiology and pathophysiology. This article is part of a Special Issue entitled: Translational Proteomics. Copyright © 2012 Elsevier B.V. All rights reserved.

Characterization of a rapid, blue light-mediated change in detectable phosphorylation of a plasma membrane protein from etiolated pea (Pisum sativum L. ) seedlings

DOE Office of Scientific and Technical Information (OSTI.GOV)

Short, T.W.; Briggs, W.R.

1990-01-01

When crude microsomal membranes from apical stem segments of etiolated Pisum sativum L. cv Alaska are mixed in vitro with {gamma}-({sup 32}P)ATP, a phosphorylated band of apparent molecular mass 120 kilodaltons can be detected on autoradiographs of sodium dodecyl sulfate electrophoresis gels. If the stem sections are exposed to blue light immediately prior to membrane isolation, this band is not evident. Comparisons of the kinetics, tissue distribution, and dark recovery of the phosphorylation response with those published for blue light mediated phototropism or rapid growth inhibition indicate that the phosphorylation could be linked to one or both of the reactionsmore » described. However, the fluence-response relationships for the change in detectable phosphorylation match quite closely those reported for phototropism but not those for growth inhibition. Blue light has also been found to regulate the capacity for in vitro phosphorylation of a second protein. It has an apparent molecular mass of 84 kilodaltons and is localized primarily in basal stem sections.« less

Implication of low level inflammation in the insulin resistance of adipose tissue at late pregnancy.

PubMed

de Castro, J; Sevillano, J; Marciniak, J; Rodriguez, R; González-Martín, C; Viana, M; Eun-suk, O H; de Mouzon, S Hauguel; Herrera, E; Ramos, M P

2011-11-01

Insulin resistance is a characteristic of late pregnancy, and adipose tissue is one of the tissues that most actively contributes to the reduced maternal insulin sensitivity. There is evidence that pregnancy is a condition of moderate inflammation, although the physiological role of this low-grade inflammation remains unclear. The present study was designed to validate whether low-grade inflammation plays a role in the development of insulin resistance in adipose tissue during late pregnancy. To this end, we analyzed proinflammatory adipokines and kinases in lumbar adipose tissue of nonpregnant and late pregnant rats at d 18 and 20 of gestation. We found that circulating and tissue levels of adipokines, such as IL-1β, plasminogen activator inhibitor-1, and TNF-α, were increased at late pregnancy, which correlated with insulin resistance. The observed increase in adipokines coincided with an enhanced activation of p38 MAPK in adipose tissue. Treatment of pregnant rats with the p38 MAPK inhibitor SB 202190 increased insulin-stimulated tyrosine phosphorylation of the insulin receptor (IR) and IR substrate-1 in adipose tissue, which was paralleled by a reduction of IR substrate-1 serine phosphorylation and an enhancement of the metabolic actions of insulin. These results indicate that activation of p38 MAPK in adipose tissue contributes to adipose tissue insulin resistance at late pregnancy. Furthermore, the results of the present study support the hypothesis that physiological low-grade inflammation in the maternal organism is relevant to the development of pregnancy-associated insulin resistance.

Phosphorylation of Dopamine Transporter Serine 7 Modulates Cocaine Analog Binding*

PubMed Central

Moritz, Amy E.; Foster, James D.; Gorentla, Balachandra K.; Mazei-Robison, Michelle S.; Yang, Jae-Won; Sitte, Harald H.; Blakely, Randy D.; Vaughan, Roxanne A.

2013-01-01

As an approach to elucidating dopamine transporter (DAT) phosphorylation characteristics, we examined in vitro phosphorylation of a recombinant rat DAT N-terminal peptide (NDAT) using purified protein kinases. We found that NDAT becomes phosphorylated at single distinct sites by protein kinase A (Ser-7) and calcium-calmodulin-dependent protein kinase II (Ser-13) and at multiple sites (Ser-4, Ser-7, and Ser-13) by protein kinase C (PKC), implicating these residues as potential sites of DAT phosphorylation by these kinases. Mapping of rat striatal DAT phosphopeptides by two-dimensional thin layer chromatography revealed basal and PKC-stimulated phosphorylation of the same peptide fragments and comigration of PKC-stimulated phosphopeptide fragments with NDAT Ser-7 phosphopeptide markers. We further confirmed by site-directed mutagenesis and mass spectrometry that Ser-7 is a site for PKC-stimulated phosphorylation in heterologously expressed rat and human DATs. Mutation of Ser-7 and nearby residues strongly reduced the affinity of rat DAT for the cocaine analog (−)-2β-carbomethoxy-3β-(4-fluorophenyl) tropane (CFT), whereas in rat striatal tissue, conditions that promote DAT phosphorylation caused increased CFT affinity. Ser-7 mutation also affected zinc modulation of CFT binding, with Ala and Asp substitutions inducing opposing effects. These results identify Ser-7 as a major site for basal and PKC-stimulated phosphorylation of native and expressed DAT and suggest that Ser-7 phosphorylation modulates transporter conformational equilibria, shifting the transporter between high and low affinity cocaine binding states. PMID:23161550

Analysis of selected sugars and sugar phosphates in mouse heart tissue by reductive amination and liquid chromatography-electrospray ionization mass spectrometry.

PubMed

Han, Jun; Tschernutter, Vera; Yang, Juncong; Eckle, Tobias; Borchers, Christoph H

2013-06-18

Sensitive and reliable analysis of sugars and sugar phosphates in tissues and cells is essential for many biological and cell engineering studies. However, the successful analysis of these endogenous compounds in biological samples by liquid chromatography/electrospray ionization mass spectrometry (LC/ESI-MS) is often difficult because of their poor chromatographic retention properties in reversed-phase LC, the complex biological matrices, and the ionization suppression in ESI. This situation is further complicated by the existence of their multiple structural isomers in vivo. This work describes the combination of reductive amination using 3-amino-9-ethylcarbazole, with a new LC approach using a pentafluorophenyl core-shell ultrahigh performance (UP) LC column and methylphosphonic acid as an efficient tail-sweeping reagent for improved chromatographic separation. This new method was used for selected detection and accurate quantitation of the major free and phosphorylated reducing sugars in mouse heart tissue. Among the detected compounds, accurate quantitation of glyceraldehyde, ribose, glucose, glycerylaldehyde-3-phosphate, ribose-5-phosphate, glucose-6-phosphate, and mannose-6-phosphate was achieved by UPLC/multiple-reaction monitoring (MRM)-MS, with analytical accuracies ranging from 87.4% to 109.4% and CVs of ≤8.5% (n = 6). To demonstrate isotope-resolved metabolic profiling, we used UPLC/quadrupole time-of-flight (QTOF)-MS to analyze the isotope distribution patterns of C3 to C6 free and phosphorylated reducing sugars in heart tissues from (13)C-labeled wild type and knockout mice. In conclusion, the preanalytical derivatization-LC/ESI-MS method has resulted in selective determination of free and phosphorylated reducing sugars without the interferences from their nonreducing structural isomers in mouse heart tissue, with analytical sensitivities in the femtomole to low picomole range.

Plasma Rich in Growth Factors Induces Cell Proliferation, Migration, Differentiation, and Cell Survival of Adipose-Derived Stem Cells.

PubMed

Mellado-López, Maravillas; Griffeth, Richard J; Meseguer-Ripolles, Jose; Cugat, Ramón; García, Montserrat; Moreno-Manzano, Victoria

2017-01-01

Adipose-derived stem cells (ASCs) are a promising therapeutic alternative for tissue repair in various clinical applications. However, restrictive cell survival, differential tissue integration, and undirected cell differentiation after transplantation in a hostile microenvironment are complications that require refinement. Plasma rich in growth factors (PRGF) from platelet-rich plasma favors human and canine ASC survival, proliferation, and delaying human ASC senescence and autophagocytosis in comparison with serum-containing cultures. In addition, canine and human-derived ASCs efficiently differentiate into osteocytes, adipocytes, or chondrocytes in the presence of PRGF. PRGF treatment induces phosphorylation of AKT preventing ASC death induced by lethal concentrations of hydrogen peroxide. Indeed, AKT inhibition abolished the PRGF apoptosis prevention in ASC exposed to 100  μ M of hydrogen peroxide. Here, we show that canine ASCs respond to PRGF stimulus similarly to the human cells regarding cell survival and differentiation postulating the use of dogs as a suitable translational model. Overall, PRGF would be employed as a serum substitute for mesenchymal stem cell amplification to improve cell differentiation and as a preconditioning agent to prevent oxidative cell death.

Role of Helicobacter pylori virulence factor cytotoxin-associated gene A in gastric mucosa-associated lymphoid tissue lymphoma

PubMed Central

Wang, Hong-Ping; Zhu, Yong-Liang; Shao, Wei

2013-01-01

Helicobacter pylori (H. pylori) infection might initiate and contribute to the progression of lymphoma from gastric mucosa-associated lymphoid tissue (MALT). Increasing evidence shows that eradication of H. pylori with antibiotic therapy can lead to regression of gastric MALT lymphoma and can result in a 10-year sustained remission. The eradication of H. pylori is the standard care for patients with gastric MALT lymphoma. Cytotoxin-associated gene A (CagA) protein, one of the most extensively studied H. pylori virulence factors, is strongly associated with the gastric MALT lymphoma. CagA possesses polymorphisms according to its C-terminal structure and displays different functions among areas and races. After being translocated into B lymphocytes via type IV secretion system, CagA deregulates intracellular signaling pathways in both tyrosine phosphorylation-dependent and -independent manners and/or some other pathways, and thereby promotes lymphomagenesis. A variety of proteins including p53 and protein tyrosine phosphatases-2 are involved in the malignant transformation induced by CagA. Mucosal inflammation is the foundational mechanism underlying the occurrence and development of gastric MALT lymphoma. PMID:24363512

Study of phosphorylation of translation elongation factor 2 (EF-2) from wheat germ.

PubMed

Smailov, S K; Lee, A V; Iskakov, B K

1993-04-26

Phosphorylation of elongation factor 2 (EF-2) by specific Ca2+/calmodulin-dependent kinase is considered as a possible mechanism of regulation of protein biosynthesis in animal cells at the level of polypeptide chain elongation. In this report we show that wheat germ EF-2 can be intensively phosphorylated by the rabbit reticulocyte EF-2 kinase. Phosphorylation results in inhibition of the activity of plant EF-2 in poly(U)-dependent cell-free translation system. Thus, the activity of EF-2 in plant cells can be potentially regulated by phosphorylation. However, we could not detect endogenous EF-2 kinase activity in wheat germ either in vitro or in vivo. Furthermore, EF-2 kinase activity is not displayed in different organs of wheat and other higher plants.

Expression of a transmembrane phosphotyrosine phosphatase inhibits cellular response to platelet-derived growth factor and insulin-like growth factor-1.

PubMed

Mooney, R A; Freund, G G; Way, B A; Bordwell, K L

1992-11-25

Tyrosine phosphorylation is a mechanism of signal transduction shared by many growth factor receptors and oncogene products. Phosphotyrosine phosphatases (PTPases) potentially modulate or counter-regulate these signaling pathways. To test this hypothesis, the transmembrane PTPase CD45 (leukocyte common antigen) was expressed in the murine cell line C127. Hormone-dependent autophosphorylation of the platelet-derived growth factor (PDGF) and insulin-like growth factor-1 (IGF-1) receptors was markedly reduced in cells expressing the transmembrane PTPase. Tyrosine phosphorylation of other PDGF-dependent phosphoproteins (160, 140, and 55 kDa) and IGF-1-dependent phosphoproteins (145 kDa) was similarly decreased. Interestingly, the pattern of growth factor-independent tyrosine phosphorylations was comparable in cells expressing the PTPase and control cells. This suggests a selectivity or accessibility of the PTPase limited to a subset of cellular phosphotyrosyl proteins. The maximum mitogenic response to PDGF and IGF-1 in cells expressing the PTPase was decreased by 67 and 71%, respectively. These results demonstrate that a transmembrane PTPase can both affect the tyrosine phosphorylation state of growth factor receptors and modulate proximal and distal cellular responses to the growth factors.

The flavonoid fisetin attenuates postischemic immune cell infiltration, activation and infarct size after transient cerebral middle artery occlusion in mice

PubMed Central

Gelderblom, Mathias; Leypoldt, Frank; Lewerenz, Jan; Birkenmayer, Gabriel; Orozco, Denise; Ludewig, Peter; Thundyil, John; Arumugam, Thiruma V; Gerloff, Christian; Tolosa, Eva; Maher, Pamela; Magnus, Tim

2012-01-01

The development of the brain tissue damage in ischemic stroke is composed of an immediate component followed by an inflammatory response with secondary tissue damage after reperfusion. Fisetin, a flavonoid, has multiple biological effects, including neuroprotective and antiinflammatory properties. We analyzed the effects of fisetin on infarct size and the inflammatory response in a mouse model of stroke, temporary middle cerebral artery occlusion, and on the activation of immune cells, murine primary and N9 microglial and Raw264.7 macrophage cells and human macrophages, in an in vitro model of inflammatory immune cell activation by lipopolysaccharide (LPS). Fisetin not only protected brain tissue against ischemic reperfusion injury when given before ischemia but also when applied 3 hours after ischemia. Fisetin also prominently inhibited the infiltration of macrophages and dendritic cells into the ischemic hemisphere and suppressed the intracerebral immune cell activation as measured by intracellular tumor necrosis factor α (TNFα) production. Fisetin also inhibited LPS-induced TNFα production and neurotoxicity of macrophages and microglia in vitro by suppressing nuclear factor κB activation and JNK/Jun phosphorylation. Our findings strongly suggest that the fisetin-mediated inhibition of the inflammatory response after stroke is part of the mechanism through which fisetin is neuroprotective in cerebral ischemia. PMID:22234339

alpha1B-Adrenergic receptor phosphorylation and desensitization induced by transforming growth factor-beta.

PubMed Central

Romero-Avila, M Teresa; Flores-Jasso, C Fabián; García-Sáinz, J Adolfo

2002-01-01

Transforming growth factor-beta (TGF-beta) induced alpha(1B)-adrenergic receptor phosphorylation in Rat-1 fibroblasts stably expressing these adrenoceptors. This effect of TGF-beta was rapid, reaching a maximum within 30 min and decreasing thereafter, and concentration-dependent (EC(50) 0.3 pM). The phosphoinositide 3-kinase inhibitors wortmannin and LY294002, and the protein kinase C inhibitors staurosporine, Ro 318220 and bisindolylmaleimide, blocked the effect of this growth factor. alpha(1B)-Adrenergic receptor phosphorylation was associated with desensitization, as indicated by a reduction in the adrenergic-mediated production of [(3)H]inositol phosphates. Phosphorylation of alpha(1B)-adrenergic receptors by TGF-beta was also observed in Cos-1 cells transfected with the receptor. Co-transfection of the dominant-negative mutant of the regulatory subunit of phosphoinositide 3-kinase (Deltap85) inhibited the phosphorylation of alpha(1B)-adrenergic receptors induced by TGF-beta. Our results indicate that activation of TGF-beta receptors induces alpha(1B)-adrenergic receptor phosphorylation and desensitization. The data suggest that phosphoinositide 3-kinase and protein kinase C play key roles in this effect of TGF-beta. PMID:12234252

alpha1B-Adrenergic receptor phosphorylation and desensitization induced by transforming growth factor-beta.

PubMed

Romero-Avila, M Teresa; Flores-Jasso, C Fabián; García-Sáinz, J Adolfo

2002-12-01

Transforming growth factor-beta (TGF-beta) induced alpha(1B)-adrenergic receptor phosphorylation in Rat-1 fibroblasts stably expressing these adrenoceptors. This effect of TGF-beta was rapid, reaching a maximum within 30 min and decreasing thereafter, and concentration-dependent (EC(50) 0.3 pM). The phosphoinositide 3-kinase inhibitors wortmannin and LY294002, and the protein kinase C inhibitors staurosporine, Ro 318220 and bisindolylmaleimide, blocked the effect of this growth factor. alpha(1B)-Adrenergic receptor phosphorylation was associated with desensitization, as indicated by a reduction in the adrenergic-mediated production of [(3)H]inositol phosphates. Phosphorylation of alpha(1B)-adrenergic receptors by TGF-beta was also observed in Cos-1 cells transfected with the receptor. Co-transfection of the dominant-negative mutant of the regulatory subunit of phosphoinositide 3-kinase (Deltap85) inhibited the phosphorylation of alpha(1B)-adrenergic receptors induced by TGF-beta. Our results indicate that activation of TGF-beta receptors induces alpha(1B)-adrenergic receptor phosphorylation and desensitization. The data suggest that phosphoinositide 3-kinase and protein kinase C play key roles in this effect of TGF-beta.

Ablation of XP-V gene causes adipose tissue senescence and metabolic abnormalities

PubMed Central

Chen, Yih-Wen; Harris, Robert A.; Hatahet, Zafer; Chou, Kai-ming

2015-01-01

Obesity and the metabolic syndrome have evolved to be major health issues throughout the world. Whether loss of genome integrity contributes to this epidemic is an open question. DNA polymerase η (pol η), encoded by the xeroderma pigmentosum (XP-V) gene, plays an essential role in preventing cutaneous cancer caused by UV radiation-induced DNA damage. Herein, we demonstrate that pol η deficiency in mice (pol η−/−) causes obesity with visceral fat accumulation, hepatic steatosis, hyperleptinemia, hyperinsulinemia, and glucose intolerance. In comparison to WT mice, adipose tissue from pol η−/− mice exhibits increased DNA damage and a greater DNA damage response, indicated by up-regulation and/or phosphorylation of ataxia telangiectasia mutated (ATM), phosphorylated H2AX (γH2AX), and poly[ADP-ribose] polymerase 1 (PARP-1). Concomitantly, increased cellular senescence in the adipose tissue from pol η−/− mice was observed and measured by up-regulation of senescence markers, including p53, p16Ink4a, p21, senescence-associated (SA) β-gal activity, and SA secretion of proinflammatory cytokines interleukin 6 (IL-6) and tumor necrosis factor α (TNF-α) as early as 4 wk of age. Treatment of pol η−/− mice with a p53 inhibitor, pifithrin-α, reduced adipocyte senescence and attenuated the metabolic abnormalities. Furthermore, elevation of adipocyte DNA damage with a high-fat diet or sodium arsenite exacerbated adipocyte senescence and metabolic abnormalities in pol η−/− mice. In contrast, reduction of adipose DNA damage with N-acetylcysteine or metformin ameliorated cellular senescence and metabolic abnormalities. These studies indicate that elevated DNA damage is a root cause of adipocyte senescence, which plays a determining role in the development of obesity and insulin resistance. PMID:26240351

The growth hormone-releasing hormone (GHRH) antagonist JV-1-36 inhibits proliferation and survival of human ectopic endometriotic stromal cells (ESCs) and the T HESC cell line.

PubMed

Annunziata, Marta; Grande, Cristina; Scarlatti, Francesca; Deltetto, Francesco; Delpiano, Elena; Camanni, Marco; Ghigo, Ezio; Granata, Riccarda

2010-08-01

To determine the effect of the GHRH antagonist JV-1-36 on proliferation and survival of primary ectopic human endometriotic stromal cells (ESCs) and the T HESC cell line. Prospective laboratory study. University hospital. 22 women with endometriosis (aged 34.8+/-5.7 years) undergoing therapeutic laparoscopy. Eutopic (n=10) and ectopic (n=22) endometrial tissues were collected from women who underwent therapeutic laparoscopic surgery for endometriosis (stage III/IV). Expression of GHRH, GHRH receptor (GHRH-R) and GHRH-R splice variant (SV) 1 mRNA was determined by reverse-transcription polymerase chain reaction (RT-PCR). The ESC proliferation was assessed by 5-bromo-2-deoxyuridine incorporation, cell survival by 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl tetrazolium bromide (MTT) and Trypan blue assay. The T HESC survival was evaluated by MTT, cyclic adenosine monophosphate (cAMP) levels by ELISA, extracellular signal-regulated kinases 1 and 2 (ERK1/2) phosphorylation by Western blot, and insulin-like growth factor (IGF)-2 mRNA by real-time PCR. The ESCs and T HESCs, but not normal endometrial tissues, expressed GHRH-R mRNA; SV1 mRNA was determined in normal endometrial tissues, ESCs, and T HESCs; GHRH mRNAwas found in T HESCs; JV-1-36 inhibited ESC proliferation and ESC and T HESC survival. In T HESCs, JV-1-36 reduced cAMP production and ERK1/2 phosphorylation but had no effect on IGF-2 mRNA expression. The GHRH antagonist JV-1-36 inhibits endometriotic cell proliferation and survival, suggesting that GHRH antagonist may represent promising tools for treatment of endometriosis. Copyright (c) 2010 American Society for Reproductive Medicine. Published by Elsevier Inc. All rights reserved.

Quantification of pancreatic cancer proteome and phosphorylome: indicates molecular events likely contributing to cancer and activity of drug targets.

PubMed

Britton, David; Zen, Yoh; Quaglia, Alberto; Selzer, Stefan; Mitra, Vikram; Löβner, Christopher; Jung, Stephan; Böhm, Gitte; Schmid, Peter; Prefot, Petra; Hoehle, Claudia; Koncarevic, Sasa; Gee, Julia; Nicholson, Robert; Ward, Malcolm; Castellano, Leandro; Stebbing, Justin; Zucht, Hans Dieter; Sarker, Debashis; Heaton, Nigel; Pike, Ian

2014-01-01

LC-MS/MS phospho-proteomics is an essential technology to help unravel the complex molecular events that lead to and propagate cancer. We have developed a global phospho-proteomic workflow to determine activity of signaling pathways and drug targets in pancreatic cancer tissue for clinical application. Peptides resulting from tryptic digestion of proteins extracted from frozen tissue of pancreatic ductal adenocarcinoma and background pancreas (n = 12), were labelled with tandem mass tags (TMT 8-plex), separated by strong cation exchange chromatography, then were analysed by LC-MS/MS directly or first enriched for phosphopeptides using IMAC and TiO2, prior to analysis. In-house, commercial and freeware bioinformatic platforms were used to identify relevant biological events from the complex dataset. Of 2,101 proteins identified, 152 demonstrated significant difference in abundance between tumor and non-tumor tissue. They included proteins that are known to be up-regulated in pancreatic cancer (e.g. Mucin-1), but the majority were new candidate markers such as HIPK1 & MLCK. Of the 6,543 unique phosphopeptides identified (6,284 unique phosphorylation sites), 635 showed significant regulation, particularly those from proteins involved in cell migration (Rho guanine nucleotide exchange factors & MRCKα) and formation of focal adhesions. Activator phosphorylation sites on FYN, AKT1, ERK2, HDAC1 and other drug targets were found to be highly modulated (≥2 fold) in different cases highlighting their predictive power. Here we provided critical information enabling us to identify the common and unique molecular events likely contributing to cancer in each case. Such information may be used to help predict more bespoke therapy suitable for an individual case.

IL-10 gene transfer upregulates arcuate POMC and ameliorates hyperphagia, obesity and diabetes by substituting for leptin.

PubMed

Nakata, M; Yamamoto, S; Okada, T; Gantulga, D; Okano, H; Ozawa, K; Yada, T

2016-03-01

Obesity and metabolic syndrome are the major risk factors for cardiovascular disease. Obesity is caused by increased food intake and/or decreased energy expenditure. Leptin potently inhibits food intake and promotes energy expenditure. These effects of leptin involve the activation of proopiomelanocortin (POMC) neurons in the hypothalamus arcuate nucleus (ARC). Disruption of leptin signaling in POMC neuron is considered one of the major causes for obesity. The present study aimed to examine whether overexpression of interleukin-10 (IL-10) could substitute for the leptin action and ameliorate obesity in leptin-deficient Lep(ob/ob) mice. Adeno-associated virus (AAV) expressing murine IL-10 (AAV-mIL-10) was injected into the skeletal muscle to overexpress IL-10 in mice. These mice were subsequently subjected to analysis of body weight, food intake, glucose metabolism and underlying mechanisms. In Lep(ob/ob) mice, AAV-IL-10 ameliorated hyperphagia, obesity, glucose intolerance and insulin resistance, as well as attenuated tumor necrosis factor-α expression. The IL-10 treatment also improved glucose-induced insulin release. Furthermore, IL-10 treatment increased POMC mRNA expression in ARC and phosphorylation of signal transducer and activator of transcription-3 (STAT3) in ARC and white adipose tissue (WAT). In neuron-specific STAT3-null mice that exhibited obesity and hyperphagia, AAV-mIL-10 administration failed to affect food intake, body weight and phosphorylation of STAT3 in WAT. These results demonstrate that peripheral overexpression of IL-10 induces STAT3 phosphorylation in ARC POMC neurons, and thereby ameliorates hyperphagia and obesity caused by leptin deficiency. IL-10 gene transfer may provide an effective approach for preventing progression of metabolic syndrome due to leptin resistance.

Differential role of Sloan–Kettering Institute (Ski) protein in Nodal and transforming growth factor-beta (TGF-β)-induced Smad signaling in prostate cancer cells

PubMed Central

Khan, Shafiq A.

2012-01-01

Transforming growth factor-beta (TGF-β) signaling pathways contain both tumor suppressor and tumor promoting activities. We have demonstrated that Nodal, another member of the TGF-β superfamily, and its receptors are expressed in prostate cancer cells. Nodal and TGF-β exerted similar biological effects on prostate cells; both inhibited proliferation in WPE, RWPE1 and DU145 cells, whereas neither had any effect on the proliferation of LNCaP or PC3 cells. Interestingly, Nodal and TGF-β induced migration in PC3 cells, but not in DU145 cells. TGF-β induced predominantly phosphorylation of Smad3, whereas Nodal induced phosphorylation of only Smad2. We also determined the expression and differential role of Ski, a corepressor of Smad2/3, in Nodal and TGF-β signaling in prostate cancer cells. Similar levels of Ski mRNA were found in several established prostate cell lines; however, high levels of Ski protein were only detected in prostate cancer cells and prostate cancer tissue samples. Exogenous Nodal and TGF-β had no effects on Ski mRNA levels. On the other hand, TGF-β induced a rapid degradation of Ski protein mediated by the proteasomal pathway, whereas Nodal had no effect on Ski protein. Reduced Ski levels correlated with increased basal and TGF-β-induced Smad2/3 phosphorylation. Knockdown of endogenous Ski reduced proliferation in DU145 cells and enhanced migration of PC3 cells. We conclude that high levels of Ski expression in prostate cancer cells may be responsible for repression of TGF-β and Smad3 signaling, but Ski protein levels do not influence Nodal and Smad2 signaling. PMID:22843506

Interleukin-6-driven progranulin expression increases cholangiocarcinoma growth by an Akt-dependent mechanism

PubMed Central

Frampton, Gabriel; Invernizzi, Pietro; Bernuzzi, Francesca; Pae, Hae Yong; Quinn, Matthew; Horvat, Darijana; Galindo, Cheryl; Huang, Li; McMillin, Matthew; Cooper, Brandon; Rimassa, Lorenza; DeMorrow, Sharon

2015-01-01

Background and objectives Cholangiocarcinoma is a devastating cancer of biliary origin with limited treatment options. The growth factor, progranulin, is overexpressed in a number of tumours. The study aims were to assess the expression of progranulin in cholangiocarcinoma and to determine its effects on tumour growth. Methods The expression and secretion of progranulin were evaluated in multiple cholangiocarcinoma cell lines and in clinical samples from patients with cholangiocarcinoma. The role of interleukin 6 (IL-6)-mediated signalling in the expression of progranulin was assessed using a combination of specific inhibitors and shRNA knockdown techniques. The effect of progranulin on proliferation and Akt activation and subsequent effects of FOXO1 phosphorylation were assessed in vitro. Progranulin knockdown cell lines were established, and the effects on cholangiocarcinoma growth were determined. Results Progranulin expression and secretion were upregulated in cholangiocarcinoma cell lines and tissue, which were in part via IL-6-mediated activation of the ERK1/2/RSK1/C/EBPβ pathway. Blocking any of these signalling molecules, by either pharmacological inhibitors or shRNA, prevented the IL-6-dependent activation of progranulin expression. Treatment of cholangiocarcinoma cells with recombinant progranulin increased cell proliferation in vitro by a mechanism involving Akt phosphorylation leading to phosphorylation and nuclear extrusion of FOXO1. Knockdown of progranulin expression in cholangiocarcinoma cells decreased the expression of proliferating cellular nuclear antigen, a marker of proliferative capacity, and slowed tumour growth in vivo. Conclusions Evidence is presented for a role for progranulin as a novel growth factor regulating cholangiocarcinoma growth. Specific targeting of progranulin may represent an alternative for the development of therapeutic strategies. PMID:22068162

Wheat germ agglutinin-conjugated liposomes incorporated with cardiolipin to improve neuronal survival in Alzheimer’s disease treatment

PubMed Central

Kuo, Yung-Chih; Lin, Che-Yu; Li, Jay-Shake; Lou, Yung-I

2017-01-01

Curcumin (CRM) and nerve growth factor (NGF) were entrapped in liposomes (LIP) with surface wheat germ agglutinin (WGA) to downregulate the phosphorylation of kinases in Alzheimer’s disease (AD) therapy. Cardiolipin (CL)-conjugated LIP carrying CRM (CRM-CL/LIP) and also carrying NGF (NGF-CL/LIP) were used with AD models of SK-N-MC cells and Wistar rats after an insult with β-amyloid peptide (Aβ). We found that CRM-CL/LIP inhibited the expression of phosphorylated p38 (p-p38), phosphorylated c-Jun N-terminal kinase (p-JNK), and p-tau protein at serine 202 and prevented neurodegeneration of SK-N-MC cells. In addition, NGF-CL/LIP could enhance the quantities of p-neurotrophic tyrosine kinase receptor type 1 and p-extracellular signal-regulated kinase 5 for neuronal rescue. Moreover, WGA-grafted CRM-CL/LIP and WGA-grafted NGF-CL/LIP significantly improved the permeation of CRM and NGF across the blood–brain barrier, reduced Aβ plaque deposition and the malondialdehyde level, and increased the percentage of normal neurons and cholinergic activity in the hippocampus of AD rats. Based on the marker expressions and in vivo evidence, current LIP carriers can be promising drug delivery systems to protect nervous tissue against Aβ-induced apoptosis in the brain during the clinical management of AD. PMID:28280340

Dehydration-responsive nuclear proteome landscape of chickpea (Cicer arietinum L.) reveals phosphorylation-mediated regulation of stress response.

PubMed

Barua, Pragya; Lande, Nilesh Vikram; Subba, Pratigya; Gayen, Dipak; Pinto, Sneha; Prasad, T S Keshav; Chakraborty, Subhra; Chakraborty, Niranjan

2018-05-10

Non-availability of water or dehydration remains recurring climatic disorder affecting yield of major food crops, legumes in particular. Nuclear proteins (NP) and phosphoproteins (NPPs) execute crucial cellular functions that form the regulatory hub for coordinated stress response. Phosphoproteins hold enormous influence over cellular signalling. Four-week-old seedlings of a grain legume, chickpea, were subjected to gradual dehydration and nuclear proteins were extracted from unstressed control as well as from 72 and 144 h stressed tissues. We identified 4832 NPs and 478 phosphosites, corresponding to 299 unique NPPs involved in multivariate cellular processes including protein modification and gene expression regulation, among others. The identified proteins included several novel kinases, phosphatases and transcription factors, besides 660 uncharacterised proteins. Spliceosome complex and splicing related proteins were dominant among differentially regulated NPPs, indicating their dehydration modulated regulation. Phospho-motif analysis revealed stress-induced enrichment of proline-directed serine phosphorylation. Association mapping of NPPs revealed predominance of differential phosphorylation of spliceosome and splicing associated proteins. Also, regulatory proteins of key processes viz., protein degradation, regulation of flowering time and circadian clock were observed to undergo dehydration-induced dephosphorylation. The characterization of novel regulatory proteins would provide new insights into stress adaptation and enable directed genetic manipulations for developing climate-resilient crops. This article is protected by copyright. All rights reserved.

Old age potentiates cold-induced tau phosphorylation: linking thermoregulatory deficit with Alzheimer's disease.

PubMed

Tournissac, Marine; Vandal, Milène; François, Arnaud; Planel, Emmanuel; Calon, Frédéric

2017-02-01

Thermoregulatory deficits coincide with a rise in the incidence of Alzheimer's disease (AD) in old age. Lower body temperature increases tau phosphorylation, a neuropathological hallmark of AD. To determine whether old age potentiates cold-induced tau phosphorylation, we compared the effects of cold exposure (4 °C, 24 hours) in 6- and 18-month-old mice. Cold-induced changes in body temperature, brown adipose tissue activity, and phosphorylation of tau at Ser202 were not different between 6- and 18-month-old mice. However, following cold exposure, only old mice displayed a significant rise in soluble tau pThr181 and pThr231, which was correlated with body temperature. Inactivation of glycogen synthase kinase 3β was more prominent in young mice, suggesting a protective mechanism against cold-induced tau phosphorylation. These results suggest that old age confers higher susceptibility to tau hyperphosphorylation following a change in body temperature, thereby contributing to an enhanced risk of developing AD. Copyright © 2016 Elsevier Inc. All rights reserved.

Xenobiotics that affect oxidative phosphorylation alter differentiation of human adipose-derived stem cells at concentrations that are found in human blood

PubMed Central

Llobet, Laura; Toivonen, Janne M.; Montoya, Julio; Ruiz-Pesini, Eduardo; López-Gallardo, Ester

2015-01-01

ABSTRACT Adipogenesis is accompanied by differentiation of adipose tissue-derived stem cells to adipocytes. As part of this differentiation, biogenesis of the oxidative phosphorylation system occurs. Many chemical compounds used in medicine, agriculture or other human activities affect oxidative phosphorylation function. Therefore, these xenobiotics could alter adipogenesis. We have analyzed the effects on adipocyte differentiation of some xenobiotics that act on the oxidative phosphorylation system. The tested concentrations have been previously reported in human blood. Our results show that pharmaceutical drugs that decrease mitochondrial DNA replication, such as nucleoside reverse transcriptase inhibitors, or inhibitors of mitochondrial protein synthesis, such as ribosomal antibiotics, diminish adipocyte differentiation and leptin secretion. By contrast, the environmental chemical pollutant tributyltin chloride, which inhibits the ATP synthase of the oxidative phosphorylation system, can promote adipocyte differentiation and leptin secretion, leading to obesity and metabolic syndrome as postulated by the obesogen hypothesis. PMID:26398948

Thyroid states regulate subcellular glucose phosphorylation activity in male mice

PubMed Central

Martins Peçanha, Flavia Letícia; dos Santos, Reinaldo Sousa

2017-01-01

The thyroid hormones (THs), triiodothyronine (T3) and thyroxine (T4), are very important in organism metabolism and regulate glucose utilization. Hexokinase (HK) is responsible for the first step of glycolysis, catalyzing the conversion of glucose to glucose 6-phosphate. HK has been found in different cellular compartments, and new functions have been attributed to this enzyme. The effects of hyperthyroidism on subcellular glucose phosphorylation in mouse tissues were examined. Tissues were removed, subcellular fractions were isolated from eu- and hyperthyroid (T3, 0.25 µg/g, i.p. during 21 days) mice and HK activity was assayed. Glucose phosphorylation was increased in the particulate fraction in soleus (312.4% ± 67.1, n = 10), gastrocnemius (369.2% ± 112.4, n = 10) and heart (142.2% ± 13.6, n = 10) muscle in the hyperthyroid group compared to the control group. Hexokinase activity was not affected in brain or liver. No relevant changes were observed in HK activity in the soluble fraction for all tissues investigated. Acute T3 administration (single dose of T3, 1.25 µg/g, i.p.) did not modulate HK activity. Interestingly, HK mRNA levels remained unchanged and HK bound to mitochondria was increased by T3 treatment, suggesting a posttranscriptional mechanism. Analysis of the AKT pathway showed a 2.5-fold increase in AKT and GSK3B phosphorylation in the gastrocnemius muscle in the hyperthyroid group compared to the euthyroid group. Taken together, we show for the first time that THs modulate HK activity specifically in particulate fractions and that this action seems to be under the control of the AKT and GSK3B pathways. PMID:28483784

Niemann-Pick Type C2 Protein Regulates Free Cholesterol Accumulation and Influences Hepatic Stellate Cell Proliferation and Mitochondrial Respiration Function.

PubMed

Wang, Yuan-Hsi; Twu, Yuh-Ching; Wang, Chung-Kwe; Lin, Fu-Zhen; Lee, Chun-Ya; Liao, Yi-Jen

2018-06-05

Liver fibrosis is the first step toward the progression to cirrhosis, portal hypertension, and hepatocellular carcinoma. A high-cholesterol diet is associated with liver fibrosis via the accumulation of free cholesterol in hepatic stellate cells (HSCs). Niemann-Pick type C2 (NPC2) plays an important role in the regulation of intracellular free cholesterol homeostasis via direct binding with free cholesterol. Previously, we reported that NPC2 was downregulated in liver cirrhosis tissues. Loss of NPC2 enhanced the accumulation of free cholesterol in HSCs and made them more susceptible to transforming growth factor (TGF)-β1. In this study, we showed that knockdown of NPC2 resulted in marked increases in platelet-derived growth factor BB (PDGF-BB)-induced HSC proliferation through enhanced extracellular signal-regulated kinases (ERK), p38, c-Jun N-terminal kinases (JNK), and protein kinase B (AKT) phosphorylation. In contrast, NPC2 overexpression decreased PDGF-BB-induced cell proliferation by inhibiting p38, JNK, and AKT phosphorylation. Although NPC2 expression did not affect caspase-related apoptosis, the autophagy marker light chain 3β (LC3B) was decreased in NPC2 knockdown, and free cholesterol accumulated in the HSCs. The mitochondrial respiration functions (such as oxygen consumption rate, ATP production, and maximal respiratory capacity) were decreased in NPC2 knockdown, and free cholesterol accumulated in the HSCs, while NPC2-overexpressed cells remained normal. In addition, NPC2 expression did not affect the susceptibility of HSCs to lipopolysaccharides (LPS), and U18666A treatment induced free cholesterol accumulation, which enhanced LPS-induced Toll-like receptor 4 (TLR4), nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) p65 phosphorylation, interleukin (IL)-1 and IL-6 expression. Our study demonstrated that NPC2-mediated free cholesterol homeostasis controls HSC proliferation and mitochondrial function.

Membrane Type 1–Matrix Metalloproteinase/Akt Signaling Axis Modulates TNF-α-Induced Procoagulant Activity and Apoptosis in Endothelial Cells

PubMed Central

Ohkawara, Hiroshi; Ishibashi, Toshiyuki; Sugimoto, Koichi; Ikeda, Kazuhiko; Ogawa, Kazuei; Takeishi, Yasuchika

2014-01-01

Membrane type 1–matrix metalloproteinase (MT1-MMP) functions as a signaling molecule in addition to a proteolytic enzyme. Our hypothesis was that MT1-MMP cooperates with protein kinase B (Akt) in tumor necrosis factor (TNF)-α-induced signaling pathways of vascular responses, including tissue factor (TF) procoagulant activity and endothelial apoptosis, in cultured human aortic endothelial cells (ECs). TNF-α (10 ng/mL) induced a decrease in Akt phosphorylation within 60 minutes in ECs. A chemical inhibitor of MMP, TIMP-2 and selective small interfering RNA (siRNA)-mediated suppression of MT1-MMP reversed TNF-α-triggered transient decrease of Akt phosphorylation within 60 minutes, suggesting that MT1-MMP may be a key regulator of Akt phosphorylation in TNF-α-stimulated ECs. In the downstream events, TNF-α increased TF antigen and activity, and suppressed the expression of thrombomodulin (TM) antigen. Inhibition of Akt markedly enhanced TNF-α-induced expression of TF antigen and activity, and further reduced the expression of TM antigen. Silencing of MT1-MMP by siRNA also reversed the changed expression of TF and TM induced by TNF-α. Moreover, TNF-α induced apoptosis of ECs through Akt- and forkhead box protein O1 (FoxO1)-dependent signaling pathway and nuclear factor-kB (NF-kB) activation. Knockdown of MT1-MMP by siRNA reversed apoptosis of ECs by inhibiting TNF-α-induced Akt-dependent regulation of FoxO1 in TNF-α-stimulated ECs. Immunoprecipitation demonstrated that TNF-α induced the changes in the associations between the cytoplasmic fraction of MT1-MMP and Akt in ECs. In conclusion, we show new evidence that MT1-MMP/Akt signaling axis is a key modifier for TNF-α-induced signaling pathways for modulation of procoagulant activity and apoptosis of ECs. PMID:25162582

Rhodopsin Kinase Activity in the Mammalian Pineal Gland and Other Tissues

NASA Astrophysics Data System (ADS)

Somers, Robert L.; Klein, David C.

1984-10-01

Rhodopsin kinase, an enzyme involved in photochemical transduction in the retina, has been found in the mammalian pineal gland in amounts equal to those in the retina; other tissues had 7 percent of this amount, or less. This finding suggests that, in mammals, rhodopsin kinase functions in the pineal gland and other tissues to phosphorylate rhodopsin-like integral membrane receptors and is thereby involved in signal transduction.

Impaired growth and neurological abnormalities in branched-chain α-keto acid dehydrogenase kinase-deficient mice

PubMed Central

Joshi, Mandar A.; Jeoung, Nam Ho; Obayashi, Mariko; Hattab, Eyas M.; Brocken, Eric G.; Liechty, Edward A.; Kubek, Michael J.; Vattem, Krishna M.; Wek, Ronald C.; Harris, Robert A.

2006-01-01

The BCKDH (branched-chain α-keto acid dehydrogenase complex) catalyses the rate-limiting step in the oxidation of BCAAs (branched-chain amino acids). Activity of the complex is regulated by a specific kinase, BDK (BCKDH kinase), which causes inactivation, and a phosphatase, BDP (BCKDH phosphatase), which causes activation. In the present study, the effect of the disruption of the BDK gene on growth and development of mice was investigated. BCKDH activity was much greater in most tissues of BDK−/− mice. This occurred in part because the E1 component of the complex cannot be phosphorylated due to the absence of BDK and also because greater than normal amounts of the E1 component were present in tissues of BDK−/− mice. Lack of control of BCKDH activity resulted in markedly lower blood and tissue levels of the BCAAs in BDK−/− mice. At 12 weeks of age, BDK−/− mice were 15% smaller than wild-type mice and their fur lacked normal lustre. Brain, muscle and adipose tissue weights were reduced, whereas weights of the liver and kidney were greater. Neurological abnormalities were apparent by hind limb flexion throughout life and epileptic seizures after 6–7 months of age. Inhibition of protein synthesis in the brain due to hyperphosphorylation of eIF2α (eukaryotic translation initiation factor 2α) might contribute to the neurological abnormalities seen in BDK−/− mice. BDK−/− mice show significant improvement in growth and appearance when fed a high protein diet, suggesting that higher amounts of dietary BCAA can partially compensate for increased oxidation in BDK−/− mice. Disruption of the BDK gene establishes that regulation of BCKDH by phosphorylation is critically important for the regulation of oxidative disposal of BCAAs. The phenotype of the BDK−/− mice demonstrates the importance of tight regulation of oxidative disposal of BCAAs for normal growth and neurological function. PMID:16875466

Intense THz pulses cause H2AX phosphorylation and activate DNA damage response in human skin tissue

PubMed Central

Titova, Lyubov V.; Ayesheshim, Ayesheshim K.; Golubov, Andrey; Fogen, Dawson; Rodriguez-Juarez, Rocio; Hegmann, Frank A.; Kovalchuk, Olga

2013-01-01

Recent emergence and growing use of terahertz (THz) radiation for medical imaging and public security screening raise questions on reasonable levels of exposure and health consequences of this form of electromagnetic radiation. In particular, picosecond-duration THz pulses have shown promise for novel diagnostic imaging techniques. However, the effects of THz pulses on human cells and tissues thus far remain largely unknown. We report on the investigation of the biological effects of pulsed THz radiation on artificial human skin tissues. We observe that exposure to intense THz pulses for ten minutes leads to a significant induction of H2AX phosphorylation, indicating that THz pulse irradiation may cause DNA damage in exposed skin tissue. At the same time, we find a THz-pulse-induced increase in the levels of several proteins responsible for cell-cycle regulation and tumor suppression, suggesting that DNA damage repair mechanisms are quickly activated. Furthermore, we find that the cellular response to pulsed THz radiation is significantly different from that induced by exposure to UVA (400 nm). PMID:23577291

Intense THz pulses cause H2AX phosphorylation and activate DNA damage response in human skin tissue.

PubMed

Titova, Lyubov V; Ayesheshim, Ayesheshim K; Golubov, Andrey; Fogen, Dawson; Rodriguez-Juarez, Rocio; Hegmann, Frank A; Kovalchuk, Olga

2013-04-01

Recent emergence and growing use of terahertz (THz) radiation for medical imaging and public security screening raise questions on reasonable levels of exposure and health consequences of this form of electromagnetic radiation. In particular, picosecond-duration THz pulses have shown promise for novel diagnostic imaging techniques. However, the effects of THz pulses on human cells and tissues thus far remain largely unknown. We report on the investigation of the biological effects of pulsed THz radiation on artificial human skin tissues. We observe that exposure to intense THz pulses for ten minutes leads to a significant induction of H2AX phosphorylation, indicating that THz pulse irradiation may cause DNA damage in exposed skin tissue. At the same time, we find a THz-pulse-induced increase in the levels of several proteins responsible for cell-cycle regulation and tumor suppression, suggesting that DNA damage repair mechanisms are quickly activated. Furthermore, we find that the cellular response to pulsed THz radiation is significantly different from that induced by exposure to UVA (400 nm).

Activation of phosphatidylinositol-3 kinase by nerve growth factor involves indirect coupling of the trk proto-oncogene with src homology 2 domains.

PubMed

Ohmichi, M; Decker, S J; Saltiel, A R

1992-10-01

Growth factor receptor tyrosine kinases can form stable associations with intracellular proteins that contain src homology (SH) 2 domains, including the p85 regulatory subunit of phosphatidylinositol (PI)-3 kinase. The activation of this enzyme by growth factors is evaluated in PC12 pheochromocytoma cells and NIH 3T3 fibroblasts expressing the pp140c-trk nerve growth factor (NGF) receptor (3T3-c-trk). NGF causes the rapid stimulation of PI-3 kinase activity detected in anti-phosphotyrosine, but not in anti-trk, immunoprecipitates. This effect coincides with the tyrosine phosphorylation of two proteins, with molecular masses of of 100 kd and 110 kd, that coimmunoprecipitate with p85. Similar phosphorylation patterns are induced when an immobilized fusion protein containing the amino-terminal SH2 domain of p85 is used to precipitate tyrosine-phosphorylated proteins. Thus, although NGF produces the rapid activation of PI-3 kinase through a mechanism that involves tyrosine phosphorylation, there is no evidence for tyrosine phosphorylation of p85, or for its ligand-dependent association with the NGF receptor. Perhaps another phosphoprotein may link the NGF receptor to this enzyme.

Asiaticoside hinders the invasive growth of keloid fibroblasts through inhibition of the GDF-9/MAPK/Smad pathway.

PubMed

Wu, Xin; Bian, Difei; Dou, Yannong; Gong, Zhunan; Tan, Qian; Xia, Yufeng; Dai, Yue

2017-08-01

Higher expression of growth differentiation factor-9 (GDF-9) in keloids compared with hypertrophic scars and normal skin tissues has been reported recently. The present study was performed to investigate the role of GDF-9 in keloid pathogenesis, and to elucidate its implication for asiaticoside in the keloid management. The data showed that GDF-9 could enhance the proliferation, migration, and invasion of keloid fibroblasts (KFs), while it only slightly elevated collagen expression, indicating that the effect of GDF-9 was opposite to that of TGF-β1. The bioactivity difference between GDF-9 and TGF-β1 could be explained by the different phosphorylated sites on the downstream Smad2/3. Moreover, asiaticoside could inhibit GDF-9-induced activation of MAPKs and Smad pathway in KFs. In conclusion, GDF-9 enhanced the invasive growth of KFs, which was achieved by phosphorylation of Smad 2/3 at the linker region through activation of MAPKs pathway. Asiaticoside hindered the invasive growth of KFs by inhibiting the GDF-9/MAPK/Smad pathway. © 2017 Wiley Periodicals, Inc.

The invasion mode of GH(3) cells is conditioned by collagen subtype, and its efficiency depends on cell-cell adhesion.

PubMed

Azorín, Erika; Solano-Agama, Carmen; Mendoza-Garrido, M Eugenia

2012-12-15

The adaptation of GH(3) cells to different microenvironments is a consequence of a partial compromise with the tumor phenotype. A collagen type IV enriched microenvironment favors an invasive phenotype and increases the substrate adhesion capacity, whereas it decreases the phosphorylation of the regulatory myosin light chain and the aggregation capacity. In contrast, the higher internal tension and increased aggregation capacity induced by collagen type I/III are factors that reduce the invasion rate. Our results show, for the first time, the importance of collagen subtypes in determining the migratory strategy: collagen I/III favors mesenchymal-like motility, whereas collagen type IV induces an ameboid-type displacement. The reciprocal modulation of the myosin light chain kinase and the Rho-kinase determines the invasive capacity through changes in tissue cohesion, extracellular matrix affinity, regulatory myosin light chain phosphorylation and spatial distribution. The collagen subtype determines which of the mechano-transduction signaling pathways will regulate the tensional homeostasis and affect the invasion ability as well as the preferred migration strategy of the cells. Copyright © 2012 Elsevier Inc. All rights reserved.

Human gingival fibroblasts express functional chemokine receptor CXCR6.

PubMed

Hosokawa, Y; Hosokawa, I; Ozaki, K; Nakae, H; Matsuo, T

2009-06-01

We have reported that CXCL16, a recently discovered transmembrane chemokine, is expressed in human gingival fibroblasts (HGF). However, it is not known whether HGF express CXCR6, the receptor for CXCL16, or CXCL16 affects HGF biology. We have shown that HGF expressed CXCR6 by reverse transcription-polymerase chain reaction and flow cytometric analysis. Moreover, we elucidated that tumour necrosis factor (TNF)-alpha and cytosine-guanine dinucleotide (CpG) DNA (Toll-like receptor-9 ligand) treatment enhanced CXCR6 expression by HGF. Interleukin (IL)-4, IL-13 and CpG DNA up-regulated CXCR6 expression by TNF-alpha-stimulated HGF. On the other hand, IL-1beta and interferon-gamma inhibited CXCR6 expression on TNF-alpha-treated HGF. CXCL16 treatment induced HGF proliferation and phosphorylation of extracellular regulated kinase (ERK) and protein kinase B (AKT) in HGF. In conclusion, HGF expressed CXCR6 functionally, because CXCL16 induced HGF proliferation and ERK and AKT phosphorylation in HGF. These results indicate that CXCL16 may play an important role in the pathogenesis and remodelling in periodontally diseased tissues.

The TRPM7 chanzyme is cleaved to release a chromatin modifying kinase

PubMed Central

Krapivinsky, Grigory; Krapivinsky, Luba; Manasian, Yunona; Clapham, David E.

2014-01-01

SUMMARY TRPM7 is a ubiquitous ion channel and kinase, a unique ‘chanzyme’, required for proper early embryonic development. It conducts Zn2+, Mg2+, Ca2+ as well as monovalent cations, and contains a functional serine/threonine kinase at its carboxyl terminus. Here, we show that in normal tissues and cell lines, the kinase is proteolytically cleaved from the channel domain in a cell type-specific manner. These TRPM7 Cleaved Kinase fragments (M7CKs) translocate to the nucleus and bind multiple components of chromatin remodeling complexes, including Polycomb group proteins. In the nucleus, the kinase phosphorylates specific serines/threonines of histones. M7CK-dependent phosphorylation of H3Ser10 at promoters of TRPM7-dependent genes correlates with their activity. We also demonstrate that cytosolic free [Zn2+] is TRPM7-dependent and regulates M7CK binding to transcription factors containing zinc-finger domains. These findings suggest that TRPM7-mediated modulation of intracellular Zn2+ concentration couples ion channel signaling to epigenetic chromatin covalent modifications that affect gene expression patterns. PMID:24855944

Methylglyoxal Mediates Adipocyte Proliferation by Increasing Phosphorylation of Akt1

PubMed Central

Jia, Xuming; Chang, Tuanjie; Wilson, Thomas W.; Wu, Lingyun

2012-01-01

Methylglyoxal (MG) is a highly reactive metabolite physiologically presented in all biological systems. The effects of MG on diabetes and hypertension have been long recognized. In the present study, we investigated the potential role of MG in obesity, one of the most important factors to cause metabolic syndrome. An increased MG accumulation was observed in the adipose tissue of obese Zucker rats. Cell proliferation assay showed that 5–20 µM of MG stimulated the proliferation of 3T3-L1 cells. Further study suggested that accumulated-MG stimulated the phosphorylation of Akt1 and its targets including p21 and p27. The activated Akt1 then increased the activity of CDK2 and accelerated the cell cycle progression of 3T3-L1 cells. The effects of MG were efficiently reversed by advanced glycation end product (AGE) breaker alagebrium and Akt inhibitor SH-6. In summary, our study revealed a previously unrecognized effect of MG in stimulating adipogenesis by up-regulation of Akt signaling pathway and this mechanism might offer a new approach to explain the development of obesity. PMID:22606274

Protein phosphorylation in plant immunity: insights into the regulation of pattern recognition receptor-mediated signaling

PubMed Central

Park, Chang-Jin; Caddell, Daniel F.; Ronald, Pamela C.

2012-01-01

Plants are continuously challenged by pathogens including viruses, bacteria, and fungi. The plant immune system recognizes invading pathogens and responds by activating an immune response. These responses occur rapidly and often involve post-translational modifications (PTMs) within the proteome. Protein phosphorylation is a common and intensively studied form of these PTMs and regulates many plant processes including plant growth, development, and immunity. Most well-characterized pattern recognition receptors (PRRs), including Xanthomonas resistance 21, flagellin sensitive 2, and elongation factor-Tu receptor, possess intrinsic protein kinase activity and regulate downstream signaling through phosphorylation events. Here, we focus on the phosphorylation events of plant PRRs that play important roles in the immune response. We also discuss the role of phosphorylation in regulating mitogen-associated protein kinase cascades and transcription factors in plant immune signaling. PMID:22876255

Combined aspirin and apatinib treatment suppresses gastric cancer cell proliferation.

PubMed

Zhang, Wei; Tan, Yongsheng; Ma, Heping

2017-11-01

Gastric cancer (GC), one of the types of tumor most prone to malignancy, is characterized by high lethality. Numerous molecular mediators of GC have been identified, including transcription factors, signaling molecules and non-coding RNAs. Recently, inhibition of angiogenesis has emerged as a potential strategy for GC therapy. In the present study, the levels of vascular endothelial growth factor (VEGF), peroxisome proliferator-activated receptor-α (PPARα) and miR-21 in GC patients and individuals without cancer, and the correlation between VEGF and miR-21, and PPARα and miR-21 expression were analyzed. In addition, the GC MKN45 cell line was treated with apatinib (a tyrosine kinase inhibitor) and aspirin (an activator of the transcription factor, PPARα) to investigate the effects of these compounds on tumorigenesis. Furthermore, the present study attempted to elucidate the molecular mechanisms of alteration of GC tumorigenesis by aspirin and apatinib. The results of the current study demonstrated that there was a higher expression of VEGF and miR-21 in GC tissues compared with that in morphologically adjacent normal tissues whereas PPARα expression was decreased. These results were confirmed in vitro , as treatment of MKN45 cells with VEGF resulted in a significant increase in miR-21 expression and a significant reduction in PPARα protein expression. Furthermore, the inhibitory effects of VEGF on PPARα mRNA and protein expression were demonstrated to be mediated by miR-21. Suppression of PPARα protein expression attenuated the inhibitory effects of miR-21 on the level of PPARα mRNA, thereby enhancing tumorigenesis in gastric cancer. Treatment of MKN45 cells with aspirin reduced the levels of phosphorylated AKT by activating PPARα, whereas treatment with apatinib inhibited the phosphorylation of vascular endothelial growth factor receptor 2 and phosphoinositide-3 kinase in MKN45 cells. Finally, treatment of MKN45 cells with apatinib and aspirin suppressed tumorigenesis by inhibiting cell proliferation, migration, invasion and colony formation. Taken together, the results of the present study indicate that treatment with a combination of aspirin and apatinib may be a potential therapeutic strategy for GC treatment.

Expression patterns of STAT3, ERK and estrogen-receptor α are associated with development and histologic severity of hepatic steatosis: a retrospective study.

PubMed

Choi, Euno; Kim, Won; Joo, Sae Kyung; Park, Sunyoung; Park, Jeong Hwan; Kang, Yun Kyung; Jin, So-Young; Chang, Mee Soo

2018-04-03

Hepatic steatosis renders hepatocytes vulnerable to injury, resulting in the progression of preexisting liver disease. Previous animal and cell culture studies implicated mammalian target of rapamycin (mTOR), signal transducer and activator of transcription-3 (STAT3), extracellular signal-regulated kinase (ERK) and estrogen-receptor α in the pathogenesis of hepatic steatosis and disease progression. However, to date there have been few studies performed using human liver tissue to study hepatic steatosis. We examined the expression patterns of mTOR, STAT3, ERK and estrogen-receptor α in liver tissues from patients diagnosed with hepatic steatosis. We reviewed the clinical and histomorphological features of 29 patients diagnosed with hepatic steatosis: 18 with non-alcoholic fatty liver disease (NAFLD), 11 with alcoholic fatty acid disease (AFLD), and a control group (16 biliary cysts and 22 hepatolithiasis). Immunohistochemistry was performed on liver tissue using an automated immunostainer. The histologic severity of hepatic steatosis was evaluated by assessing four key histomorphologic parameters common to NAFLD and AFLD: steatosis, lobular inflammation, ballooning degeneration and fibrosis. mTOR, phosphorylated STAT3, phosphorylated pERK, estrogen-receptor α were found to be more frequently expressed in the hepatic steatosis group than in the control group. Specifically, mTOR was expressed in 78% of hepatocytes, and ERK in 100% of hepatic stellate cells, respectively, in patients with NAFLD. Interestingly, estrogen-receptor α was diffusely expressed in hepatocytes in all NALFD cases. Phosphorylated (active) STAT3 was expressed in 73% of hepatocytes and 45% of hepatic stellate cells in patients with AFLD, and phosphorylated (active) ERK was expressed in hepatic stellate cells in all AFLD cases. Estrogen-receptor α was expressed in all AFLD cases (focally in 64% of AFLD cases, and diffusely in 36%). Phosphorylated STAT3 expression in hepatocytes and hepatic stellate cells correlated with severe lobular inflammation, severe ballooning degeneration and advanced fibrosis, whereas diffusely expressed estrogen-receptor α correlated with a mild stage of fibrosis. Our data indicate ERK activation and estrogen-receptor α may be relevant in the development of hepatic steatosis. However, diffuse expression of estrogen-receptor α would appear to impede disease progression, including hepatic fibrosis. Finally, phosphorylated STAT3 may also contribute to disease progression.

Soya protein attenuates abnormalities of the renin-angiotensin system in adipose tissue from obese rats.

PubMed

Frigolet, María E; Torres, Nimbe; Tovar, Armando R

2012-01-01

Several metabolic disturbances during obesity are associated with adipose tissue-altered functions. Adipocytes contain the renin-angiotensin system (RAS), which regulates signalling pathways that control angiogenesis via Akt in an autocrine fashion. Soya protein (Soy) consumption modifies the gene expression pattern in adipose tissue, resulting in an improved adipocyte function. Therefore, the aim of the present work is to study whether dietary Soy regulates the expression of RAS and angiogenesis-related genes and its association with the phosphorylated state of Akt in the adipose tissue of obese rats. Animals were fed a 30 % Soy or casein (Cas) diet containing 5 or 25 % fat for 160 d. mRNA abundance was studied in the adipose tissue, and Akt phosphorylation and hormone release were measured in the primary adipocyte culture. The present results show that Soy treatment in comparison with Cas consumption induces lower angiotensin release and increased insulin-stimulated Akt activation in adipocytes. Furthermore, Soy consumption varies the expression of RAS and angiogenesis-related genes, which maintain cell size and vascularity in the adipose tissue of rats fed a high-fat diet. Thus, adipocyte hypertrophy and impaired angiogenesis, which are frequently observed in dysfunctional adipose tissue, were avoided by consuming dietary Soy. Taken together, these findings suggest that Soy can be used as a dietary strategy to preserve adipocyte functionality and to prevent obesity abnormalities.

IGF-1-induced MMP-11 expression promotes the proliferation and invasion of gastric cancer cells through the JAK1/STAT3 signaling pathway.

PubMed

Su, Chao; Wang, Wenchang; Wang, Cunchuan

2018-05-01

The present study aimed to investigate the association between insulin-like growth factor-1 (IGF-1) and matrix metalloproteinase-11 (MMP-11) expression in gastric cancer (GC) and the underlying mechanisms in SGC-7901 cells. Reverse transcription-quantitative polymerase chain reaction analysis revealed that the expression of IGF-1 and MMP-11 was significantly upregulated in GC tissues compared with normal gastric tissue. Furthermore, IGF-1 significantly and dose-dependently promoted MMP-11. Western blotting revealed that the addition of IGF-1 to SGC-7901 cells led to an evident enhancement in signal transducer and activator of transcription 3 (STAT3), IGF-1R and Janus kinase 1 (JAK1) phosphorylation at 20 and 40 min. A decrease in the extent of the elevated expression of MMP-11 and the enhanced phosphorylation of STAT3, JAK1 and IGF-1 receptor (IGF-1R) induced by IGF-1 in SGC-7901 cells were observed following treatment with NT157 (an IGF-1R inhibitor). Furthermore, piceatannol (a JAK1 inhibitor) or small interfering RNA against STAT3 reduced the extent of the increased expression of MMP-11 induced by IGF-1 in SGC-7901 cells. Piceatannol treatment induced the dose-dependent decline in the enhancement of STAT3 phosphorylation induced by IGF-1, indicating that the JAK1/STAT3 pathway may be implicated in the elevated expression of MMP-11 induced by IGF-1 in SGC-7901 cells. Finally, IGF-1 treatment significantly promoted the proliferation and invasion of SGC-7901 cells, which was inhibited following NT157, piceatannol or si-STAT3 treatment. The present study therefore demonstrated that IGF-1-induced MMP-11 may have facilitated the proliferation and invasion of SGC-7901 cells via the JAK1/STAT3 pathway.

Ameliorative effects of Qingfei Tongluo formula on experimental mycoplasmal pneumonia in mice.

PubMed

Jiang, Yong-hong; Yu, Jian-er; Guo, Ai-hua; Li, Xiao; Lin, Yan; Jiang, Zhi-yan; Xiao, Zhen

2016-04-01

Mycoplasma pneumoniae pneumonia (MPP) is a common disease in children. Qingfei Tongluo formula (QTF) has been used for the treatment of MPP clinically, but the chemical constituents and mechanism involved remain unclear. This study aimed to analyze the main chemical constituents and to explore the possible mechanism of action associated with QTF treatment of MPP. Liquid chromatography-mass spectrometry was employed to identify the compounds contained in the QTF extract. A BALB/c mouse model of MP infection was established. After treatment with QTF (0.85 and 1.70 g/kg) for 3 days, hematoxylin and eosin staining was performed in lung tissues for histological examination. Inflammatory cytokines were detected by ELISA. Western blot analysis was used for detecting phosphorylated proteins involved in MAPK and nuclear factor (NF)-κB signaling pathways. In the mouse model, a large amount of pulmonary interstitial infiltration of lymphocytes and plasmacytes were seen as well as bronchus and vasodilation congestion. Following QTF treatment, inflammation was alleviated significantly compared with the model group. Inflammatory cytokines [interleukin (IL)-6, transforming growth factor-β1, IL-8, IL-1β and tumor necrosis factor-α] in bronchoalveolar lavage fluid were decreased dramatically. In addition, we found that QTF inhibited activation of phosphorylation of JNK, ERK and NF-κB. In conclusion, QTF alleviates MPP inflammation possibly via inhibitory activation of MAPK/NF-κB pathways, which can act as a new agent for MPP treatment.

Epidermal growth factor receptor signaling mediates aldosterone-induced profibrotic responses in kidney

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sheng, Lili; Yang, Min; Ding, Wei

Aldosterone has been recognized as a risk factor for the development of chronic kidney disease (CKD). Studies have indicated that enhanced activation of epidermal growth factor receptor (EGFR) is associated with the development and progression of renal fibrosis. But if EGFR is involved in aldosterone-induced renal fibrosis is less investigated. In the present study, we examined the effect of erlotinib, an inhibitor of EGFR tyrosine kinase activity, on the progression of aldosterone-induced renal profibrotic responses in a murine model underwent uninephrectomy. Erlotinib-treated rats exhibited relieved structural lesion comparing with rats treated with aldosterone alone, as characterized by glomerular hypertrophy, mesangialmore » cell proliferation and expansion. Also, erlotinib inhibited the expression of TGF-β, α-SMA and mesangial matrix proteins such as collagen Ⅳ and fibronectin. In cultured mesangial cells, inhibition of EGFR also abrogated aldosterone-induced expression of extracellular matrix proteins, cell proliferation and migration. We also demonstrated that aldosterone induced the phosphorylation of EGFR through generation of ROS. And the activation of EGFR resulted in the phosphorylation of ERK1/2, leading to the activation of profibrotic pathways. Taken together, we concluded that aldosterone-mediated tissue fibrosis relies on ROS induced EGFR/ERK activation, highlighting EGFR as a potential therapeutic target for modulating renal fibrosis. - Highlights: • EGFR was involved in aldosterone-induced renal profibrotic responses. • Aldosterone-induced EGFR activation was mediated by MR-dependent ROS generation. • EGFR activated the MAPK/ERK1/2 signaling to promote renal fibrosis.« less

Growth and differentiation factor 11 (GDF11): Functions in the regulation of erythropoiesis and cardiac regeneration.

PubMed

Rochette, Luc; Zeller, Marianne; Cottin, Yves; Vergely, Catherine

2015-12-01

Members of the TGF-β superfamily transduce their signals through type I and II receptor serine/threonine kinases. The regulation of members of the TGF-β family is known to be complex, because many proteins able to bind the ligands and inhibit their activities have been identified. Growth and differentiation factor 11 (Gdf11) as activins belong to the TGF-β family. GDF11, like other members of the TGF-β superfamily, is produced from precursor proteins by proteolytic processing. The binding of activins to activin type IIA (ActRIIA) or type IIB (ActRIIB) receptors induces the recruitment and phosphorylation of an activin type I receptor which then phosphorylates the Smad2 and Smad3 intracellular signaling proteins. GDF11 signal through the ActRIIB pathway. Recent studies have reported that GDF11-ActRIIB-Smad2/3-dependent signaling is a key regulatory mechanism in proliferating erythroid precursors as it controls their late-stage maturation. The administration of GDF11 is effective in experimental cardiac hypertrophy, and the identification of GDF11 as a "rejuvenating factor" opens up perspectives for the treatment of age-related cardiac dysfunction. Recent studies of the heart indicate that exposure to young blood reverses age-related impairments. GDF11 could be one of the circulating molecules that influence the aging of different tissues. Is GDF11 an "elixir of youth"? Copyright © 2015 Elsevier Inc. All rights reserved.

The interaction of protein-tyrosine phosphatase α (PTPα) and RACK1 protein enables insulin-like growth factor 1 (IGF-1)-stimulated Abl-dependent and -independent tyrosine phosphorylation of PTPα.

PubMed

Khanna, Ranvikram S; Le, Hoa T; Wang, Jing; Fung, Thomas C H; Pallen, Catherine J

2015-04-10

Protein tyrosine phosphatase α (PTPα) promotes integrin-stimulated cell migration in part through the role of Src-phosphorylated PTPα-Tyr(P)-789 in recruiting and localizing p130Cas to focal adhesions. The growth factor IGF-1 also stimulates PTPα-Tyr-789 phosphorylation to positively regulate cell movement. This is in contrast to integrin-induced PTPα phosphorylation, that induced by IGF-1 can occur in cells lacking Src family kinases (SFKs), indicating that an unknown kinase distinct from SFKs can target PTPα. We show that this IGF-1-stimulated tyrosine kinase is Abl. We found that PTPα binds to the scaffold protein RACK1 and that RACK1 coordinates the IGF-1 receptor, PTPα, and Abl in a complex to enable IGF-1-stimulated and Abl-dependent PTPα-Tyr-789 phosphorylation. In cells expressing SFKs, IGF-1-stimulated phosphorylation of PTPα is mediated by RACK1 but is Abl-independent. Furthermore, expressing the SFKs Src and Fyn in SFK-deficient cells switches IGF-1-induced PTPα phosphorylation to occur in an Abl-independent manner, suggesting that SFK activity dominantly regulates IGF-1/IGF-1 receptor signaling to PTPα. RACK1 is a molecular scaffold that integrates growth factor and integrin signaling, and our identification of PTPα as a RACK1 binding protein suggests that RACK1 may coordinate PTPα-Tyr-789 phosphorylation in these signaling networks to promote cell migration. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

Impact of Doxorubicin Treatment on the Physiological Functions of White Adipose Tissue

PubMed Central

Cruz, Maysa Mariana; Cunha, Roberta D. C.; Alonso-Vale, Maria Isabel; Oyama, Lila Missae; Nascimento, Claudia M. Oller; Pimentel, Gustavo Duarte; dos Santos, Ronaldo V. T.; Lira, Fabio Santos

2016-01-01

White adipose tissue (WAT) plays a fundamental role in maintaining energy balance and important endocrine functions. The loss of WAT modifies adipokine secretion and disrupts homeostasis, potentially leading to severe metabolic effects and a reduced quality of life. Doxorubicin is a chemotherapeutic agent used clinically because of its good effectiveness against various types of cancer. However, doxorubicin has deleterious effects in many healthy tissues, including WAT, liver, and skeletal and cardiac muscles. Our objective was to investigate the effects of doxorubicin on white adipocytes through in vivo and in vitro experiments. Doxorubicin reduced the uptake of glucose by retroperitoneal adipocytes and 3T3-L1 cells via the inhibition of AMP-activated protein kinase Thr172 phosphorylation and glucose transporter 4 content. Doxorubicin also reduced the serum level of adiponectin and, to a greater extent, the expression of genes encoding lipogenic (Fas and Acc) and adipogenic factors (Pparg, C/ebpa, and Srebp1c) in retroperitoneal adipose tissue. In addition, doxorubicin inhibited both lipogenesis and lipolysis and reduced the hormone-sensitive lipase and adipose tissue triacylglycerol lipase protein levels. Therefore, our results demonstrate the impact of doxorubicin on WAT. These results are important to understand some side effects observed in patients receiving chemotherapy and should encourage new adjuvant treatments that aim to inhibit these side effects. PMID:27015538

Biochemical analysis of force-sensitive responses using a large-scale cell stretch device.

PubMed

Renner, Derrick J; Ewald, Makena L; Kim, Timothy; Yamada, Soichiro

2017-09-03

Physical force has emerged as a key regulator of tissue homeostasis, and plays an important role in embryogenesis, tissue regeneration, and disease progression. Currently, the details of protein interactions under elevated physical stress are largely missing, therefore, preventing the fundamental, molecular understanding of mechano-transduction. This is in part due to the difficulty isolating large quantities of cell lysates exposed to force-bearing conditions for biochemical analysis. We designed a simple, easy-to-fabricate, large-scale cell stretch device for the analysis of force-sensitive cell responses. Using proximal biotinylation (BioID) analysis or phospho-specific antibodies, we detected force-sensitive biochemical changes in cells exposed to prolonged cyclic substrate stretch. For example, using promiscuous biotin ligase BirA* tagged α-catenin, the biotinylation of myosin IIA increased with stretch, suggesting the close proximity of myosin IIA to α-catenin under a force bearing condition. Furthermore, using phospho-specific antibodies, Akt phosphorylation was reduced upon stretch while Src phosphorylation was unchanged. Interestingly, phosphorylation of GSK3β, a downstream effector of Akt pathway, was also reduced with stretch, while the phosphorylation of other Akt effectors was unchanged. These data suggest that the Akt-GSK3β pathway is force-sensitive. This simple cell stretch device enables biochemical analysis of force-sensitive responses and has potential to uncover molecules underlying mechano-transduction.

Fibroin and Sericin from Bombyx mori Silk Stimulate Cell Migration through Upregulation and Phosphorylation of c-Jun

PubMed Central

García-Vizcaíno, Eva María; Alcaraz, Antonia; Cenis, José Luis; Nicolás, Francisco José

2012-01-01

Wound healing is a biological process directed to the restoration of tissue that has suffered an injury. An important phase of wound healing is the generation of a basal epithelium able to wholly replace the epidermis of the wound. A broad range of products derived from fibroin and sericin from Bombyx mori silk are used to stimulate wound healing. However, so far the molecular mechanism underlying this phenomenon has not been elucidated. The aim of this work was to determine the molecular basis underlying wound healing properties of silk proteins using a cell model. For this purpose, we assayed fibroin and sericin in a wound healing scratch assay using MDA-MB-231 and Mv1Lu cells. Both proteins stimulated cell migration. Furthermore, treatment with sericin and fibroin involved key factors of the wound healing process such as upregulation of c-Jun and c-Jun protein phosphorylation. Moreover, fibroin and sericin stimulated the phosphorylation of ERK 1/2 and JNK 1/2 kinases. All these experiments were done in the presence of specific inhibitors for some of the cell signalling pathways referred above. The obtained results revealed that MEK, JNK and PI3K pathways are involved in fibroin and sericin stimulated cells migration. Inhibition of these three kinases prevented c-Jun upregulation and phosphorylation by fibroin or sericin. Fibroin and sericin were tested in the human keratinocyte cell line, HaCaT, with similar results. Altogether, our results showed that fibroin and sericin initiate cell migration by activating the MEK, JNK and PI3K signalling pathways ending in c-Jun activation. PMID:22860103

Mucin1 shifts Smad3 signaling from the tumor-suppressive pSmad3C/p21(WAF1) pathway to the oncogenic pSmad3L/c-Myc pathway by activating JNK in human hepatocellular carcinoma cells.

PubMed

Li, Qiongshu; Liu, Guomu; Yuan, Hongyan; Wang, Juan; Guo, Yingying; Chen, Tanxiu; Zhai, Ruiping; Shao, Dan; Ni, Weihua; Tai, Guixiang

2015-02-28

Mucin1 (MUC1) is a transmembrane glycoprotein that acts as an oncogene in human hepatic tumorigenesis. Hepatocellular carcinoma (HCC) cells often gain advantage by reducing the tumor-suppressive activity of transforming growth factor beta (TGF-β) together with stimulation of its oncogenic activity as in MUC1 expressing HCC cells; however, molecular mechanisms remain largely unknown. Type I TGF-β receptor (TβRI) and c-Jun NH2-terminal kinase (JNK) differentially phosphorylate Smad3 mediator to create 2 phosphorylated forms: COOH-terminally phosphorylated Smad3 (pSmad3C) and linker-phosphorylated Smad3 (pSmad3L). Here, we report that MUC1 overexpression in HCC cell lines suppresses TβRI-mediated pSmad3C signaling which involves growth inhibition by up-regulating p21(WAF1). Instead, MUC1 directly activates JNK to stimulate oncogenic pSmad3L signaling, which fosters cell proliferation by up-regulating c-Myc. Conversely, MUC1 gene silencing in MUC1 expressing HCC cells results in preserved tumor-suppressive function via pSmad3C, while eliminating pSmad3L-mediated oncogenic activity both in vitro and in vivo. In addition, high correlation between MUC1 and pSmad3L/c-Myc but not pSmad3C/p21(WAF1) expression was observed in HCC tissues from patients. Collectively, these results indicate that MUC1 shifts Smad3 signaling from a tumor-suppressive pSmad3C/p21(WAF1) to an oncogenic pSmad3L/c-Myc pathway by directly activating JNK in HCC cells, suggesting that MUC1 is an important target for HCC therapy.

Coniferyl Aldehyde Reduces Radiation Damage Through Increased Protein Stability of Heat Shock Transcriptional Factor 1 by Phosphorylation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kim, Seo-Young; Lee, Hae-June; Nam, Joo-Won

Purpose: We previously screened natural compounds and found that coniferyl aldehyde (CA) was identified as an inducer of HSF1. In this study, we further examined the protective effects of CA against ionizing radiation (IR) in normal cell system. Methods and Materials: Western blotting and reverse transcription-polymerase chain reaction tests were performed to evaluate expression of HSF1, HSP27, and HSP70 in response to CA. Cell death and cleavage of PARP and caspase-3 were analyzed to determine the protective effects of CA in the presence of IR or taxol. The protective effects of CA were also evaluated using animal models. Results: CAmore » increased stability of the HSF1 protein by phosphorylation at Ser326, which was accompanied by increased expression of HSP27 and HSP70. HSF1 phosphorylation at Ser326 by CA was mediated by EKR1/2 activation. Cotreatment of CA with IR or taxol in normal cells induced protective effects with phosphorylation- dependent patterns at Ser326 of HSF1. The decrease in bone marrow (BM) cellularity and increase of terminal deoxynucleotidyl transferase dUTP nick end labeling–positive BM cells by IR were also significantly inhibited by CA in mice (30.6% and 56.0%, respectively). A549 lung orthotopic lung tumor model indicated that CA did not affect the IR-mediated reduction of lung tumor nodules, whereas CA protected normal lung tissues from the therapeutic irradiation. Conclusions: These results suggest that CA may be useful for inducing HSF1 to protect against normal cell damage after IR or chemotherapeutic agents.« less

Collagen Type I Selectively Activates Ectodomain Shedding of the Discoidin Domain Receptor 1: Involvement of Src Tyrosine Kinase

PubMed Central

Slack, Barbara E.; Siniaia, Marina S.; Blusztajn, Jan K.

2008-01-01

The discoidin domain receptor 1 (DDR1) is a receptor tyrosine kinase that is highly expressed in breast carcinoma cells. Upon binding to collagen, DDR1 undergoes autophosphorylation followed by limited proteolysis to generate a tyrosine phosphorylated C-terminal fragment (CTF). Although it was postulated that this fragment is formed as a result of shedding of the N-terminal ectodomain, collagen-dependent release of the DDR1 extracellular domain has not been demonstrated. We now report that, in conjunction with CTF formation, collagen type I stimulates concentration-dependent, saturable shedding of the DDR1 ectodomain from two carcinoma cell lines, and from transfected cells. In contrast, collagen did not promote cleavage of other transmembrane proteins including the amyloid precursor protein (APP), ErbB2, and E-cadherin. Collagen-dependent tyrosine phosphorylation and proteolysis of DDR1 in carcinoma cells were reduced by a pharmacologic Src inhibitor. Moreover, expression of a dominant negative Src mutant protein in human embryonic kidney cells inhibited collagen-dependent phosphorylation and shedding of co-transfected DDR1. The hydroxamate-based metalloproteinase inhibitor TAPI-1 (tumor necrosis factor-α protease inhibitor-1), and tissue inhibitor of metalloproteinase (TIMP)-3, also blocked collagen-evoked DDR1 shedding, but did not reduce levels of the phosphorylated CTF. Neither shedding nor CTF formation were affected by the γ-secretase inhibitor, L-685,458. The results demonstrate that collagen-evoked ectodomain cleavage of DDR1 is mediated in part by Src-dependent activation or recruitment of a matrix- or disintegrin metalloproteinase, and that CTF formation can occur independently of ectodomain shedding. Delayed shedding of the DDR1 ectodomain may represent a mechanism that limits DDR1-dependent cell adhesion and migration on collagen matrices. PMID:16440311

The cyclolignan PPP induces activation loop-specific inhibition of tyrosine phosphorylation of the insulin-like growth factor-1 receptor. Link to the phosphatidyl inositol-3 kinase/Akt apoptotic pathway.

PubMed

Vasilcanu, Daiana; Girnita, Ada; Girnita, Leonard; Vasilcanu, Radu; Axelson, Magnus; Larsson, Olle

2004-10-14

The insulin-like growth factor-1 receptor (IGF-1R) is crucial for many functions in neoplastic cells, for example, antiapoptosis. Recently, we demonstrated that the cyclolignan PPP efficiently inhibited phosphorylation of IGF-1R without interfering with insulin receptor activity. PPP preferentially reduced phosphorylated Akt, as compared to phosphorylated Erk1/2, and caused apoptosis. Now, we aimed to investigate how PPP inhibits the IGF-1R tyrosine kinase (IGF-1RTK) and the PI3K/Akt apoptotic pathway. Using a baculovirus driven IGF-1RTK we found that PPP interfered with tyrosine phosphorylation in the activation loop of the kinase domain. Specifically, it blocked phosphorylation of tyrosine (Y) 1136, while sparing the two others (Y1131 and Y1135). To explore the impact of inhibition of Y1136 on Akt phosphorylation we transfected P6 cells (overexpressing IGF-1R) and malignant melanoma cells with different IGF-1R mutants, including Y1136F (tyrosine replaced by phenylalanine). Y1136F was found to strongly decrease IGF-1 stimulated phosphorylation of Akt. Conversely, Akt phosphorylation was weakly affected in the Y1131F transfectant. Taken together, our data suggest that the preferential inhibition of phosphorylated Akt, after PPP treatment, may be due to specific inhibition of Y1136. PPP was proven not to interfere directly with Akt or any of its downstream molecules in the apoptotic pathway.

Gelatin-based hydrogel for vascular endothelial growth factor release in peripheral nerve tissue engineering.

PubMed

Gnavi, S; di Blasio, L; Tonda-Turo, C; Mancardi, A; Primo, L; Ciardelli, G; Gambarotta, G; Geuna, S; Perroteau, I

2017-02-01

Hydrogels are promising materials in regenerative medicine applications, due to their hydrophilicity, biocompatibility and capacity to release drugs and growth factors in a controlled manner. In this study, biocompatible and biodegradable hydrogels based on blends of natural polymers were used in in vitro and ex vivo experiments as a tool for VEGF-controlled release to accelerate the nerve regeneration process. Among different candidates, the angiogenic factor VEGF was selected, since angiogenesis has been long recognized as an important and necessary step during tissue repair. Recent studies have pointed out that VEGF has a beneficial effect on motor neuron survival and Schwann cell vitality and proliferation. Moreover, VEGF administration can sustain and enhance the growth of regenerating peripheral nerve fibres. The hydrogel preparation process was optimized to allow functional incorporation of VEGF, while preventing its degradation and denaturation. VEGF release was quantified through ELISA assay, whereas released VEGF bioactivity was validated in human umbilical vein endothelial cells (HUVECs) and in a Schwann cell line (RT4-D6P2T) by assessing VEGFR-2 and downstream effectors Akt and Erk1/2 phosphorylation. Moreover, dorsal root ganglia explants cultured on VEGF-releasing hydrogels displayed increased neurite outgrowth, providing confirmation that released VEGF maintained its effect, as also confirmed in a tubulogenesis assay. In conclusion, a gelatin-based hydrogel system for bioactive VEGF delivery was developed and characterized for its applicability in neural tissue engineering. Copyright © 2014 John Wiley & Sons, Ltd. Copyright © 2014 John Wiley & Sons, Ltd.

Pr-specific phytochrome phosphorylation in vitro by a protein kinase present in anti-phytochrome maize immunoprecipitates

NASA Technical Reports Server (NTRS)

Biermann, B. J.; Pao, L. I.; Feldman, L. J.

1994-01-01

Protein kinase activity has repeatedly been found to co-purify with the plant photoreceptor phytochrome, suggesting that light signals received by phytochrome may be transduced or modulated through protein phosphorylation. In this study immunoprecipitation techniques were used to characterize protein kinase activity associated with phytochrome from maize (Zea mays L.). A protein kinase that specifically phosphorylated phytochrome was present in washed anti-phytochrome immunoprecipitates of etiolated coleoptile proteins. No other substrate tested was phosphorylated by this kinase. Adding salts or detergents to disrupt low-affinity protein interactions reduced background phosphorylation in immunoprecipitates without affecting phytochrome phosphorylation, indicating that the protein kinase catalytic activity is either intrinsic to the phytochrome molecule or associated with it by high-affinity interactions. Red irradiation (of coleoptiles or extracts) sufficient to approach photoconversion saturation reduced phosphorylation of immunoprecipitated phytochrome. Subsequent far-red irradiation reversed the red-light effect. Phytochrome phosphorylation was stimulated about 10-fold by a co-immunoprecipitated factor. The stimulatory factor was highest in immunoprecipitates when Mg2+ was present in immunoprecipitation reactions but remained in the supernatant in the absence of Mg2+. These observations provide strong support for the hypothesis that phytochrome-associated protein kinase modulates light responses in vivo. Since only phytochrome was found to be phosphorylated, the co-immunoprecipitated protein kinase may function to regulate receptor activity.

Implication of Low Level Inflammation in the Insulin Resistance of Adipose Tissue at Late Pregnancy

PubMed Central

de Castro, J.; Sevillano, J.; Marciniak, J.; Rodriguez, R.; González-Martín, C.; Viana, M.; Eun-suk, O. H.; de Mouzon, S. Hauguel; Herrera, E.

2011-01-01

Insulin resistance is a characteristic of late pregnancy, and adipose tissue is one of the tissues that most actively contributes to the reduced maternal insulin sensitivity. There is evidence that pregnancy is a condition of moderate inflammation, although the physiological role of this low-grade inflammation remains unclear. The present study was designed to validate whether low-grade inflammation plays a role in the development of insulin resistance in adipose tissue during late pregnancy. To this end, we analyzed proinflammatory adipokines and kinases in lumbar adipose tissue of nonpregnant and late pregnant rats at d 18 and 20 of gestation. We found that circulating and tissue levels of adipokines, such as IL-1β, plasminogen activator inhibitor-1, and TNF-α, were increased at late pregnancy, which correlated with insulin resistance. The observed increase in adipokines coincided with an enhanced activation of p38 MAPK in adipose tissue. Treatment of pregnant rats with the p38 MAPK inhibitor SB 202190 increased insulin-stimulated tyrosine phosphorylation of the insulin receptor (IR) and IR substrate-1 in adipose tissue, which was paralleled by a reduction of IR substrate-1 serine phosphorylation and an enhancement of the metabolic actions of insulin. These results indicate that activation of p38 MAPK in adipose tissue contributes to adipose tissue insulin resistance at late pregnancy. Furthermore, the results of the present study support the hypothesis that physiological low-grade inflammation in the maternal organism is relevant to the development of pregnancy-associated insulin resistance. PMID:21914778

Inhibition of ribosome recruitment induces stress granule formation independently of eukaryotic initiation factor 2alpha phosphorylation.

PubMed

Mazroui, Rachid; Sukarieh, Rami; Bordeleau, Marie-Eve; Kaufman, Randal J; Northcote, Peter; Tanaka, Junichi; Gallouzi, Imed; Pelletier, Jerry

2006-10-01

Cytoplasmic aggregates known as stress granules (SGs) arise as a consequence of cellular stress and contain stalled translation preinitiation complexes. These foci are thought to serve as sites of mRNA storage or triage during the cell stress response. SG formation has been shown to require induction of eukaryotic initiation factor (eIF)2alpha phosphorylation. Herein, we investigate the potential role of other initiation factors in this process and demonstrate that interfering with eIF4A activity, an RNA helicase required for the ribosome recruitment phase of translation initiation, induces SG formation and that this event is not dependent on eIF2alpha phosphorylation. We also show that inhibition of eIF4A activity does not impair the ability of eIF2alpha to be phosphorylated under stress conditions. Furthermore, we observed SG assembly upon inhibition of cap-dependent translation after poliovirus infection. We propose that SG modeling can occur via both eIF2alpha phosphorylation-dependent and -independent pathways that target translation initiation.

Inhibition of Ribosome Recruitment Induces Stress Granule Formation Independently of Eukaryotic Initiation Factor 2α Phosphorylation

PubMed Central

Mazroui, Rachid; Sukarieh, Rami; Bordeleau, Marie-Eve; Kaufman, Randal J.; Northcote, Peter; Tanaka, Junichi; Gallouzi, Imed

2006-01-01

Cytoplasmic aggregates known as stress granules (SGs) arise as a consequence of cellular stress and contain stalled translation preinitiation complexes. These foci are thought to serve as sites of mRNA storage or triage during the cell stress response. SG formation has been shown to require induction of eukaryotic initiation factor (eIF)2α phosphorylation. Herein, we investigate the potential role of other initiation factors in this process and demonstrate that interfering with eIF4A activity, an RNA helicase required for the ribosome recruitment phase of translation initiation, induces SG formation and that this event is not dependent on eIF2α phosphorylation. We also show that inhibition of eIF4A activity does not impair the ability of eIF2α to be phosphorylated under stress conditions. Furthermore, we observed SG assembly upon inhibition of cap-dependent translation after poliovirus infection. We propose that SG modeling can occur via both eIF2α phosphorylation-dependent and -independent pathways that target translation initiation. PMID:16870703

Skeletal muscle PLIN3 and PLIN5 are serine phosphorylated at rest and following lipolysis during adrenergic or contractile stimulation

PubMed Central

MacPherson, Rebecca E K; Vandenboom, Rene; Roy, Brian D; Peters, Sandra J

2013-01-01

In adipose tissue, access of adipose triglyceride and hormone-sensitive lipases (ATGL and HSL) to the lipid droplet depends on PLIN1 phosphorylation, however, PLIN1 is not expressed in skeletal muscle and the phosphorylation of the expressed PLINs has yet to be investigated. Further, direct interactions between skeletal muscle PLINs and HSL are unknown. We investigated the isolated and combined effects of epinephrine and contraction on PLIN-to-lipase interactions as well as phosphorylation. Isolated rat solei were assigned to one of four 30 min in vitro conditions (25°C): (1) rest; (2) intermittent tetanic stimulation (60 Hz for 150 msec; train rate 20/min); (3) 5 nmol/L epinephrine; (4) intermittent tetanic stimulation and 5 nmol/L epinephrine. Immunoprecipitation of serine phosphorylated proteins followed by Western blotting for PLIN2, PLIN3, PLIN5, revealed that only PLIN2 is not phosphorylated under any of the experimental conditions. This is the first study to show that in whole rat skeletal muscle PLIN3 and PLIN5 are serine phosphorylated. The degree of serine phosphorylation remained unchanged following adrenergic and/or contractile stimulation. Oil red O staining of muscle sections for lipid content shows a significant decrease following each condition, confirming lipolysis occurred (P < 0.05). PLIN2, 3, and 5 all interact with HSL and ATGL, but these interactions were unchanged following treatments. Our results show that in skeletal muscle, PLIN2 is not serine phosphorylated at rest or with lipolytic stimulation and that while PLIN3, PLIN5 are serine phosphorylated at rest, the degree of phosphorylation does not change with lipolytic stimulation. PMID:24303154

Blocking of the EGFR-STAT3 signaling pathway through afatinib treatment inhibited the intrahepatic cholangiocarcinoma

PubMed Central

Zhang, Changhe; Xu, Hong; Zhou, Zhenping; Tian, Ye; Cao, Xiaofei; Cheng, Guochang; Liu, Qinghong

2018-01-01

Epidermal growth factor receptor (EGFR) and downstream signal transducer and activator of transcription 3 (STAT3) signaling have been extensively implicated in various human neoplasms. Recently, a novel EGFR inhibitor, known as afatinib, has exhibited broad antitumor activities in a variety of tumors. Therefore, the present study attempted to investigate the impact of this agent on intrahepatic cholangiocarcinoma (ICC). Initially, immunohistochemical assays were performed on 15 human ICC specimens and their adjacent tissues in order to assess the protein levels of phosphorylated EGFR (pEGFR) and pSTAT3. Subsequently, the human ICC cell lines JCK and OZ were exposed to different doses of afatinib, and then cell viability and apoptosis were determined by MTT assay and flow cytometry, respectively. Furthermore, immunoblotting was applied to detect any variations in the phosphorylated protein levels of EGFR and STAT3 in afatinib-treated ICC cells. The results of the current study demonstrated that ICC specimens had evidently increased pEGFR and pSTAT3 protein levels as compared with the adjacent noncancerous tissues. Further in vitro experiments indicated that afatinib evidently blocked ICC cell growth and induced cell apoptosis. At the protein level, pEGFR and pSTAT3 were evidently attenuated by afatinib-administration. In conclusion, the present study clearly determined that afatinib exerts an antitumor effect on ICC cells by silencing the EGFR-STAT3 signaling pathway. This novel agent deserves further investigation as a potential therapeutic strategy for ICC. PMID:29805522

Overexpression of protein kinase FA/GSK-3 alpha (a proline-directed protein kinase) correlates with human hepatoma dedifferentiation/progression.

PubMed

Yang, S D; Yu, J S; Yang, C C; Lee, S C; Lee, T T; Ni, M H; Kuan, C Y; Chen, H C

1996-05-01

Computer analysis of protein phosphorylation sites sequence revealed that transcriptional factors and viral oncoproteins are prime targets for regulation of proline-directed protein phosphorylation, suggesting an association of the proline-directed protein kinase (PDPK) family with neoplastic transformation and tumorigenesis. In this report, an immunoprecipitate activity assay of protein kinase FA/glycogen synthase kinase-3 alpha (kinase F(A)/GSK-3 alpha) (a member of PDPK family) has been optimized for human hepatoma and used to demonstrate for the first time significantly increased (P < 0.01) activity in poorly differentiated SK-Hep-1 hepatoma (24.2 +/- 2.8 units/mg) and moderately differentiated Mahlavu hepatoma (14.5 +/- 2.2 units/mg) when compared to well differentiated Hep 3B hepatoma (8.0 +/- 2.4 units/mg). Immunoblotting analysis revealed that increased activity of kinase FA/GSK-3 alpha is due to overexpression of the protein. Elevated kinase FA/GSK-3 alpha expression in human hepatoma biopsies relative to normal liver tissue was found to be even more profound. This kinase appeared to be fivefold overexpressed in well differentiated hepatoma and 13-fold overexpressed in poorly differentiated hepatoma when compared to normal liver tissue. Taken together, the results provide initial evidence that overexpression of kinase FA/GSK-3 alpha is involved in human hepatoma dedifferentiation/progression. Since kinase FA/GSK-3 alpha is a PDPK, the results further support a potential role of this kinase in human liver tumorigenesis, especially in its dedifferentiation/progression.

Leucine-rich Repeat Neuronal Protein 1 Regulates Differentiation of Embryonic Stem Cells by Posttranslational Modifications of Pluripotency Factors.

PubMed

Liao, Chien Huang; Wang, Ya-Hui; Chang, Wei-Wei; Yang, Bei-Chia; Wu, Tsai-Jung; Liu, Wei-Li; Yu, Alice L; Yu, John

2018-06-11

Stem cell surface markers may facilitate a better understanding of stem cell biology through molecular function studies or serve as tools to monitor the differentiation status and behavior of stem cells in culture or tissue. Thus, it is important to identify additional, novel stem cell markers. We used glycoproteomics to discover surface glycoproteins on human embryonic stem cells (hESCs) that may be useful stem cell markers. We found that a surface glycoprotein, leucine-rich repeat neuronal protein 1 (LRRN1), is expressed abundantly on the surface of hESCs prior to differentiation into embryoid bodies (EBs). Silencing of LRRN1 with short hairpin RNA (shLRRN1) in hESCs resulted in decreased capacity of self-renewal, and skewed differentiation toward endoderm/mesoderm lineages in vitro and in vivo. Meanwhile, the protein expression levels of the pluripotency factors OCT4, NANOG and SOX2 were reduced. Interestingly, the mRNA levels of these pluripotency factors were not affected in LRRN1 silenced cells, but protein half-lives were substantially shortened. Furthermore, we found LRRN1 silencing led to nuclear export and proteasomal degradation of all three pluripotency factors. In addition, the effects on nuclear export were mediated by AKT phosphorylation. These results suggest that LRRN1 plays an important role in maintaining the protein stability of pluripotency factors through AKT phosphorylation, thus maintaining hESC self-renewal capacity and pluripotency. Overall, we found that LRRN1 contributes to pluripotency of hESC by preventing translocation of OCT4, NANOG and SOX2 from nucleus to cytoplasm, thereby lessening their post-translational modification and degradation. This article is protected by copyright. All rights reserved. © 2018 AlphaMed Press.

A mechanism by which dietary trans fats cause atherosclerosis.

PubMed

Chen, Chun-Lin; Tetri, Laura H; Neuschwander-Tetri, Brent A; Huang, Shuan Shian; Huang, Jung San

2011-07-01

Dietary trans fats (TFs) have been causally linked to atherosclerosis, but the mechanism by which they cause the disease remains elusive. Suppressed transforming growth factor (TGF)-β responsiveness in aortic endothelium has been shown to play an important role in the pathogenesis of atherosclerosis in animals with hypercholesterolemia. We investigated the effects of a high TF diet on TGF-β responsiveness in aortic endothelium and integration of cholesterol in tissues. Here, we show that normal mice fed a high TF diet for 24 weeks exhibit atherosclerotic lesions and suppressed TGF-β responsiveness in aortic endothelium. The suppressed TGF-β responsiveness is evidenced by markedly reduced expression of TGF-β type I and II receptors and profoundly decreased levels of phosphorylated Smad2, an important TGF-β response indicator, in aortic endothelium. These mice exhibit greatly increased integration of cholesterol into tissue plasma membranes. These results suggest that dietary TFs cause atherosclerosis, at least in part, by suppressing TGF-β responsiveness. This effect is presumably mediated by the increased deposition of cholesterol into cellular plasma membranes in vascular tissue, as in hypercholesterolemia. Copyright © 2011 Elsevier Inc. All rights reserved.

Transcriptional regulation of hepatic lipogenesis.

PubMed

Wang, Yuhui; Viscarra, Jose; Kim, Sun-Joong; Sul, Hei Sook

2015-11-01

Fatty acid and fat synthesis in the liver is a highly regulated metabolic pathway that is important for very low-density lipoprotein (VLDL) production and thus energy distribution to other tissues. Having common features at their promoter regions, lipogenic genes are coordinately regulated at the transcriptional level. Transcription factors, such as upstream stimulatory factors (USFs), sterol regulatory element-binding protein 1C (SREBP1C), liver X receptors (LXRs) and carbohydrate-responsive element-binding protein (ChREBP) have crucial roles in this process. Recently, insights have been gained into the signalling pathways that regulate these transcription factors. After feeding, high blood glucose and insulin levels activate lipogenic genes through several pathways, including the DNA-dependent protein kinase (DNA-PK), atypical protein kinase C (aPKC) and AKT-mTOR pathways. These pathways control the post-translational modifications of transcription factors and co-regulators, such as phosphorylation, acetylation or ubiquitylation, that affect their function, stability and/or localization. Dysregulation of lipogenesis can contribute to hepatosteatosis, which is associated with obesity and insulin resistance.

Elevation of transforming growth factor beta (TGFbeta) and its downstream mediators in subcutaneous foreign body capsule tissue.

PubMed

Li, Allen G; Quinn, Matthew J; Siddiqui, Yasmin; Wood, Michael D; Federiuk, Isaac F; Duman, Heather M; Ward, W Kenneth

2007-08-01

Foreign body encapsulation represents a chronic fibrotic response and has been a major obstacle that reduces the useful life of implanted biomedical devices. The precise mechanism underlying such an encapsulation is still unknown. We hypothesized that, considering its central role in many other fibrotic conditions, transforming growth factor beta (TGFbeta) may play an important role during the formation of foreign body capsule (FBC). In the present study, we implanted mock sensors in rats subcutaneously and excised FBC samples at day 7, 21, and 48-55 postimplantation. The most abundant TGFbeta isoform in all tissues was TGFbeta1, which was expressed minimally in control tissue. The expression of both TGFbeta1 RNA and protein was significantly increased in FBC tissues at all time points, with the highest level in day 7 FBC. The number of cells stained for phosphorylated Smad2, an indication of activated TGFbeta signaling, paralleled the expression of TGFbeta. A similar dynamic change was also observed in the numbers of FBC myofibroblasts, which in response to TGFbeta, differentiate from quiescent fibroblasts and synthesize collagen. Type I collagen, the most prominent downstream target of TGFbeta in fibrosis, was found in abundance in the FBC, especially during the latter time periods. We suggest that TGFbeta plays an important role in the FBC formation. Inhibition of TGFbeta signaling could be a promising strategy in the prevention of FBC formation, thereby extending the useful life of subcutaneous implants.

Induction of c-fos expression through JNK-mediated TCF/Elk-1 phosphorylation.

PubMed Central

Cavigelli, M; Dolfi, F; Claret, F X; Karin, M

1995-01-01

Growth factors induce c-fos transcription by stimulating phosphorylation of transcription factor TCF/Elk-1, which binds to the serum response element (SRE). Under such conditions Elk-1 could be phosphorylated by the mitogen-activated protein kinases (MAPKs) ERK1 and ERK2. However, c-fos transcription and SRE activity are also induced by stimuli, such as UV irradiation and activation of the protein kinase MEKK1, that cause only an insignificant increase in ERK1/2 activity. However, both of these stimuli strongly activate two other MAPKs, JNK1 and JNK2, and stimulate Elk-1 transcriptional activity and phosphorylation. We find that the JNKs are the predominant Elk-1 activation domain kinases in extracts of UV-irradiated cells and that immunopurified JNK1/2 phosphorylate Elk-1 on the same major sites recognized by ERK1/2, that potentiate its transcriptional activity. Finally, we show that UV irradiation, but not serum or phorbol esters, stimulate translocation of JNK1 to the nucleus. As Elk-1 is most likely phosphorylated while bound to the c-fos promoter, these results suggest that UV irradiation and MEKK1 activation stimulate TCF/Elk-1 activity through JNK activation, while growth factors induce c-fos through ERK activation. Images PMID:8846788

Increased expression of phosphorylated forms of RNA-dependent protein kinase and eukaryotic initiation factor 2α may signal skeletal muscle atrophy in weight-losing cancer patients

PubMed Central

Eley, H L; Skipworth, R J E; Deans, D A C; Fearon, K C H; Tisdale, M J

2007-01-01

Previous studies suggest that the activation (autophosphorylation) of dsRNA-dependent protein kinase (PKR) can stimulate protein degradation, and depress protein synthesis in skeletal muscle through phosphorylation of the translation initiation factor 2 (eIF2) on the α-subunit. To understand whether these mediators are important in muscle wasting in cancer patients, levels of the phospho forms of PKR and eIF2α have been determined in rectus abdominus muscle of weight losing patients with oesophago-gastric cancer, in comparison with healthy controls. Levels of both phospho PKR and phospho eIF2α were significantly enhanced in muscle of cancer patients with weight loss irrespective of the amount and there was a linear relationship between phosphorylation of PKR and phosphorylation of eIF2α (correlation coefficient 0.76, P=0.005). This suggests that phosphorylation of PKR led to phosphorylation of eIF2α. Myosin levels decreased as the weight loss increased, and there was a linear relationship between myosin expression and the extent of phosphorylation of eIF2α (correlation coefficient 0.77, P=0.004). These results suggest that phosphorylation of PKR may be an important initiator of muscle wasting in cancer patients. PMID:18087277

Mammalian transcription factor LSF is a target of ERK signaling

PubMed Central

Pagon, Zrinka; Volker, Janet; Cooper, Geoffrey M.; Hansen, Ulla

2012-01-01

LSF is a mammalian transcription factor that is rapidly and quantitatively phosphorylated upon growth induction of resting, peripheral human T cells, as assayed by a reduction in its electrophoretic mobility. The DNA-binding activity of LSF in primary T cells is greatly increased after this phosphorylation event [Volker et al., 1997]. We demonstrate here that LSF is also rapidly and quantitatively phosphorylated upon growth induction in NIH 3T3 cells, although its DNA-binding activity is not significantly altered. Three lines of experimentation established that ERK is responsible for phosphorylating LSF upon growth induction in both cell types. First, phosphorylation of LSF by ERK is sufficient to cause the reduced electrophoretic mobility of LSF. Second, the amount of ERK activity correlates with the extent of LSF phosphorylation in both primary human T cells and NIH 3T3 cells. Finally, specific inhibitors of the Ras/Raf/MEK/ERK pathway inhibit LSF modification in vivo. This phosphorylation by ERK is not sufficient for activation of LSF DNA-binding activity, as evidenced both in vitro and in mouse fibroblasts. Nonetheless, activation of ERK is a prerequisite for the substantial increase in LSF DNA-binding activity upon activation of resting T cells, indicating that ERK phosphorylation is necessary but not sufficient for activation of LSF in this cell type. PMID:12858339

YAP and TAZ in epithelial stem cells: A sensor for cell polarity, mechanical forces and tissue damage.

PubMed

Elbediwy, Ahmed; Vincent-Mistiaen, Zoé I; Thompson, Barry J

2016-07-01

The YAP/TAZ family of transcriptional co-activators drives cell proliferation in epithelial tissues and cancers. Yet, how YAP and TAZ are physiologically regulated remains unclear. Here we review recent reports that YAP and TAZ act primarily as sensors of epithelial cell polarity, being inhibited when cells differentiate an apical membrane domain, and being activated when cells contact the extracellular matrix via their basal membrane domain. Apical signalling occurs via the canonical Crumbs/CRB-Hippo/MST-Warts/LATS kinase cascade to phosphorylate and inhibit YAP/TAZ. Basal signalling occurs via Integrins and Src family kinases to phosphorylate and activate YAP/TAZ. Thus, YAP/TAZ is localised to the nucleus in basal stem/progenitor cells and cytoplasm in differentiated squamous cells or columnar cells. In addition, other signals such as mechanical forces, tissue damage and possibly receptor tyrosine kinases (RTKs) can influence MST-LATS or Src family kinase activity to modulate YAP/TAZ activity. © 2016 The Authors BioEssays Published by WILEY Periodicals, Inc.

Prokaryotic expression of bone sialoprotein and identification of casein kinase II phosphorylation sites.

PubMed

Saad, Fawzy A; Salih, Erdjan; Wunderlich, Livius; Flückiger, Rudolf; Glimcher, Melvin J

2005-07-29

Bone sialoprotein is an extracellular noncollagenous acidic protein that plays a role in bone mineralization and remodeling. Its expression is restricted to mineralized tissues and is subjected to variety of posttranslational modifications including phosphorylation and glycosylation. We have expressed the full-length and half domains of bovine bone sialoprotein in a prokaryotic system and identified the phosphorylation sites of casein kinase II. The N-terminal automated solid-phase sequencing defined four phosphorylated peptides: residues 28-38 (LEDS(P)EENGVFK), 51-86 (FYPELKRFAVQSSS(P)DS(P)S(P)EENGNGDS(P)S(P)EEEEEEEETS(P)), 151-165 (EDES(P)DEEEEEEEEEE), and 295-305 (GRGYDS(P)YDGQD). Nine phosphoserines were identified within the four peptides. Seven of them were in the N-terminus (S31, S64, S66, S67, S75, S76, and S86) and two were in the C-terminus (S154 and S300) of the protein.

Involvement of nuclear factor κB in platelet CD40 signaling.

PubMed

Hachem, Ahmed; Yacoub, Daniel; Zaid, Younes; Mourad, Walid; Merhi, Yahye

2012-08-17

CD40 ligand (CD40L) is a thrombo-inflammatory molecule that predicts cardiovascular events. Platelets constitute the major source of soluble CD40L (sCD40L), which has been shown to potentiate platelet activation and aggregation, in a CD40-dependent manner, via p38 mitogen activated protein kinase (MAPK) and Rac1 signaling. In many cells, the CD40L/CD40 dyad also induces activation of nuclear factor kappa B (NF-κB). Given that platelets contain NF-κB, we hypothesized that it may be involved in platelet CD40 signaling and function. In human platelets, sCD40L induces association of CD40 with its adaptor protein the tumor necrosis factor receptor associated factor 2 and triggers phosphorylation of IκBα, which are abolished by CD40L blockade. Inhibition of IκBα phosphorylation reverses sCD40L-induced IκBα phosphorylation without affecting p38 MAPK phosphorylation. On the other hand, inhibition of p38 MAPK phosphorylation has no effect on IκBα phosphorylation, indicating a divergence in the signaling pathway originating from CD40 upon its ligation. In functional studies, inhibition of IκBα phosphorylation reverses sCD40L-induced platelet activation and potentiation of platelet aggregation in response to a sub-threshold concentration of collagen. This study demonstrates that the sCD40L/CD40 axis triggers NF-κB activation in platelets. This signaling pathway plays a critical role in platelet activation and aggregation upon sCD40L stimulation and may represent an important target against thrombo-inflammatory disorders. Copyright © 2012 Elsevier Inc. All rights reserved.

Brief Report: S6 Ribosomal Protein Phosphorylation in Autistic Frontal Cortex and Cerebellum: A Tissue Array Analysis

ERIC Educational Resources Information Center

Eberhart, Charles G.; Copeland, Joshua; Abel, Ty W.

2006-01-01

Few autistic brain samples are available for study, limiting investigations into molecular and histopathological abnormalities associated with this common disease. To facilitate distribution of samples, we have constructed a tissue array containing cerebral and cerebellar cores from 5 autistic children, 1 girl with Rett syndrome, and 5 age-matched…

Quantifying Kinase-Specific Phosphorylation Stoichiometry Using Stable Isotope Labeling In a Reverse In-Gel Kinase Assay

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, Xiang; Cox, Jonathan T.; Huang, Weiliang

2016-12-06

Reversible protein phosphorylation regulates essentially all cellular activities. Aberrant protein phosphorylation is an etiological factor in a wide array of diseases, including cancer1, diabetes2, and Alzheimer’s3. Given the broad impact of protein phosphorylation on cellular biology and organismal health, understanding how protein phosphorylation is regulated and the consequences of gain and loss of phosphoryl moieties from proteins is of primary importance. Advances in instrumentation, particularly in mass spectrometry, coupled with high throughput approaches have recently yielded large datasets cataloging tens of thousands of protein phosphorylation sites in multiple organisms4-6. While these studies are seminal in term of data collection, ourmore » understanding of protein phosphorylation regulation remains largely one-dimensional.« less

Protein Tyrosine Phosphatase 1B Regulates Pyruvate Kinase M2 Tyrosine Phosphorylation*

PubMed Central

Bettaieb, Ahmed; Bakke, Jesse; Nagata, Naoto; Matsuo, Kosuke; Xi, Yannan; Liu, Siming; AbouBechara, Daniel; Melhem, Ramzi; Stanhope, Kimber; Cummings, Bethany; Graham, James; Bremer, Andrew; Zhang, Sheng; Lyssiotis, Costas A.; Zhang, Zhong-Yin; Cantley, Lewis C.; Havel, Peter J.; Haj, Fawaz G.

2013-01-01

Protein-tyrosine phosphatase 1B (PTP1B) is a physiological regulator of glucose homeostasis and adiposity and is a drug target for the treatment of obesity and diabetes. Here we identify pyruvate kinase M2 (PKM2) as a novel PTP1B substrate in adipocytes. PTP1B deficiency leads to increased PKM2 total tyrosine and Tyr105 phosphorylation in cultured adipocytes and in vivo. Substrate trapping and mutagenesis studies identify PKM2 Tyr-105 and Tyr-148 as key sites that mediate PTP1B-PKM2 interaction. In addition, in vitro analyses illustrate a direct effect of Tyr-105 phosphorylation on PKM2 activity in adipocytes. Importantly, PTP1B pharmacological inhibition increased PKM2 Tyr-105 phosphorylation and decreased PKM2 activity. Moreover, PKM2 Tyr-105 phosphorylation is regulated nutritionally, decreasing in adipose tissue depots after high-fat feeding. Further, decreased PKM2 Tyr-105 phosphorylation correlates with the development of glucose intolerance and insulin resistance in rodents, non-human primates, and humans. Together, these findings identify PKM2 as a novel substrate of PTP1B and provide new insights into the regulation of adipose PKM2 activity. PMID:23640882

TNFα-induced IKKβ complex activation influences epithelial, but not stromal cell survival in endometriosis.

PubMed

Kocbek, Vida; Grandi, Giovanni; Blank, Fabian; Wotzkow, Carlos; Bersinger, Nick A; Mueller, Michael D; Kyo, Satoru; McKinnon, Brett D

2016-11-01

Can the activity of the IκB kinase (IKKβ) complex in endometriotic cells contribute to endometriotic lesion survival? There is a constitutive activity of the IKKβ catalytic complex in peritoneal and deeply infiltrating lesions that can influence epithelial, but not stromal cell viability. Endometriotic lesions exist in an inflammatory microenvironment with higher local concentrations of cytokines, such as tumour necrosis factor α (TNFα). TNFα stimulates the activation of the IKKβ complex, an important nodal point in multiple signalling pathways that influence gene transcription, proliferation and apoptosis. However, few data on the regulation of IKKβ in endometriotic tissue are currently available. A retrospective analysis of endometriotic tissue from peritoneal, ovarian and deeply infiltrating lesions from 37 women. Basal and activated (phosphorylated) IKKβ concentrations were analysed by western blotting and immunohistochemistry. The relationship between the expression and activation of these proteins and peritoneal fluid (TNFα) concentrations, measured via ELISA, was examined. A subsequent in vitro analysis of TNFα treatment on the activation of IKKβ and the effect on epithelial and stromal cell viability by its inhibition with PS1145 was also performed. Levels of the phosphorylated IKKβ complex in endometriotic lesions had a significant positive correlation with peritoneal fluid TNFα concentrations. Phosphorylated IKKβ complex was more prevalent in peritoneal and deeply infiltrating endometriosis lesions compared with ovarian lesions. IKKβ was present in both epithelial and stromal cells in all lesions but active IKKβ was limited to epithelial cells. TNFα stimulated an increased expression of phosphorylated IKKβ and the inhibition of this kinase with PS1145 significantly influenced ectopic epithelial cells viability but not eutopic epithelial cells, or endometrial stromal cells. In vitro analysis on epithelial cells was performed with immortalized cell lines and not primary cell cultures and only low sample numbers were available for the study. The regulation of aberrant signalling pathways represents a promising yet relatively unexplored area of endometriosis progression. The IKKβ complex is activated by inflammation and is critical nodal point of numerous downstream kinase-signalling pathways, including NFκB (nuclear factor κB), mTOR (mammalian target of rapamycin) and BAD (Bcl2-antagonist of cell death). This study shows a significant relationship between peritoneal fluid TNFα and IKKβ activation in epithelial cells that will have significant consequences for the continued survival of these cells at ectopic locations through the regulation of downstream pathways. None. The study was funded by the Swiss National Science Foundation (Grant Number 320030_140774). The authors have no conflict of interest to declare. © The Author 2016. Published by Oxford University Press on behalf of the European Society of Human Reproduction and Embryology. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

N-terminal tyrosine phosphorylation of caveolin-2 negates anti-proliferative effect of transforming growth factor beta in endothelial cells

PubMed Central

Abel, Britain; Willoughby, Cara; Jang, Sungchan; Cooper, Laura; Xie, Leike; Vo-Ransdell, Chi; Sowa, Grzegorz

2012-01-01

Here we show that tyrosine phosphorylation of caveolin-2 (Cav-2) negatively regulates the anti-proliferative function of transforming growth factor beta (TGF-beta) in endothelial cells. In contrast to wild-type-Cav-2, retroviral re-expression of Y19/27F-Cav-2 in Cav-2 knockout endothelial cells did not affect anti-proliferative effect of TGF-beta compared to empty vector. Conversely, although less effective than wild-type, re-expression of S23/36A-Cav-2 reduced the effect of TGF-beta compared to empty vector. This differential effect of tyrosine and serine phosphorylation mutants of Cav-2 correlated with TGF-beta-induced Smad3 phosphorylation and transcriptional activation of plasminogen activator inhibitor-1. Thus tyrosine-phosphorylated Cav-2 counteracts anti-proliferative effect of TGF-beta in endothelial cells. PMID:22819829

Alginate Sulfates Mitigate Binding Kinetics of Proangiogenic Growth Factors with Receptors toward Revascularization.

PubMed

Schmidt, John; Lee, Min Kyung; Ko, Eunkyung; Jeong, Jae Hyun; DiPietro, Luisa A; Kong, Hyunjoon

2016-07-05

Ever since proangiogenic growth factors have been used as a vascular medicine to treat tissue ischemia, efforts have been increasingly made to develop a method to enhance efficacy of growth factors in recreating microvascular networks, especially at low dose. To this end, we hypothesized that polysaccharides substituted with sulfate groups would amplify growth factor receptor activation and stimulate phenotypic activities of endothelial cells involved in neovascularization. We examined this hypothesis by modifying alginate with a controlled number of sulfates and using it to derive a complex with vascular endothelial growth factor (VEGF), as confirmed with fluorescence resonance energy transfer (FRET) assay. Compared with the bare VEGF and with a mixture of VEGF and unmodified alginates, the VEGF complexed with alginate sulfates significantly reduced the dissociation rate with the VEGFR-2, elevated VEGFR-2 phosphorylation level, and increased the number of endothelial sprouts in vitro. Furthermore, the VEGF-alginate sulfate complex improved recovery of perfusion in an ischemic hindlimb of a mouse due to the increase of the capillary density. Overall, this study not only demonstrates an important cofactor of VEGF but also uncovers an underlying mechanism by which the cofactor mitigates the VEGF-induced signaling involved in the binding kinetics and activation of VEGFR. We therefore believe that the results of this study will be highly useful in improving the therapeutic efficacy of various growth factors and expediting their uses in clinical treatments of wounds and tissue defects.

Regulation of a transcription factor network by Cdk1 coordinates late cell cycle gene expression

PubMed Central

Landry, Benjamin D; Mapa, Claudine E; Arsenault, Heather E; Poti, Kristin E; Benanti, Jennifer A

2014-01-01

To maintain genome stability, regulators of chromosome segregation must be expressed in coordination with mitotic events. Expression of these late cell cycle genes is regulated by cyclin-dependent kinase (Cdk1), which phosphorylates a network of conserved transcription factors (TFs). However, the effects of Cdk1 phosphorylation on many key TFs are not known. We find that elimination of Cdk1-mediated phosphorylation of four S-phase TFs decreases expression of many late cell cycle genes, delays mitotic progression, and reduces fitness in budding yeast. Blocking phosphorylation impairs degradation of all four TFs. Consequently, phosphorylation-deficient mutants of the repressors Yox1 and Yhp1 exhibit increased promoter occupancy and decreased expression of their target genes. Interestingly, although phosphorylation of the transcriptional activator Hcm1 on its N-terminus promotes its degradation, phosphorylation on its C-terminus is required for its activity, indicating that Cdk1 both activates and inhibits a single TF. We conclude that Cdk1 promotes gene expression by both activating transcriptional activators and inactivating transcriptional repressors. Furthermore, our data suggest that coordinated regulation of the TF network by Cdk1 is necessary for faithful cell division. PMID:24714560

Regulation of a transcription factor network by Cdk1 coordinates late cell cycle gene expression.

PubMed

Landry, Benjamin D; Mapa, Claudine E; Arsenault, Heather E; Poti, Kristin E; Benanti, Jennifer A

2014-05-02

To maintain genome stability, regulators of chromosome segregation must be expressed in coordination with mitotic events. Expression of these late cell cycle genes is regulated by cyclin-dependent kinase (Cdk1), which phosphorylates a network of conserved transcription factors (TFs). However, the effects of Cdk1 phosphorylation on many key TFs are not known. We find that elimination of Cdk1-mediated phosphorylation of four S-phase TFs decreases expression of many late cell cycle genes, delays mitotic progression, and reduces fitness in budding yeast. Blocking phosphorylation impairs degradation of all four TFs. Consequently, phosphorylation-deficient mutants of the repressors Yox1 and Yhp1 exhibit increased promoter occupancy and decreased expression of their target genes. Interestingly, although phosphorylation of the transcriptional activator Hcm1 on its N-terminus promotes its degradation, phosphorylation on its C-terminus is required for its activity, indicating that Cdk1 both activates and inhibits a single TF. We conclude that Cdk1 promotes gene expression by both activating transcriptional activators and inactivating transcriptional repressors. Furthermore, our data suggest that coordinated regulation of the TF network by Cdk1 is necessary for faithful cell division.

Shade-induced nuclear localization of PIF7 is regulated by phosphorylation and 14-3-3 proteins in Arabidopsis.

PubMed

Huang, Xu; Zhang, Qian; Jiang, Yupei; Yang, Chuanwei; Wang, Qianyue; Li, Lin

2018-06-21

Shade avoidance syndrome enables shaded plants to grow and compete effectively against their neighbors. In Arabidopsis , the shade-induced de-phosphorylation of the transcription factor PIF7 (PHYTOCHROME-INTERACTING FACTOR 7) is the key event linking light perception to stem elongation. However, the mechanism through which phosphorylation regulates the activity of PIF7 is unclear. Here, we show that shade light induces the de-phosphorylation and nuclear accumulation of PIF7. Phosphorylation-resistant site mutations in PIF7 result in increased nuclear localization and shade-induced gene expression, and consequently augment hypocotyl elongation. PIF7 interacts with 14-3-3 proteins. Blocking the interaction between PIF7 and 14-3-3 proteins or reducing the expression of 14-3-3 proteins accelerates shade-induced nuclear localization and de-phosphorylation of PIF7, and enhances the shade phenotype. By contrast, the 14-3-3 overexpressing line displays an attenuated shade phenotype. These studies demonstrate a phosphorylation-dependent translocation of PIF7 when plants are in shade and a novel mechanism involving 14-3-3 proteins, mediated by the retention of PIF7 in the cytoplasm that suppresses the shade response. © 2018, Huang et al.

Artificial Sweeteners Stimulate Adipogenesis and Suppress Lipolysis Independently of Sweet Taste Receptors*

PubMed Central

Simon, Becky R.; Parlee, Sebastian D.; Learman, Brian S.; Mori, Hiroyuki; Scheller, Erica L.; Cawthorn, William P.; Ning, Xiaomin; Gallagher, Katherine; Tyrberg, Björn; Assadi-Porter, Fariba M.; Evans, Charles R.; MacDougald, Ormond A.

2013-01-01

G protein-coupled receptors mediate responses to a myriad of ligands, some of which regulate adipocyte differentiation and metabolism. The sweet taste receptors T1R2 and T1R3 are G protein-coupled receptors that function as carbohydrate sensors in taste buds, gut, and pancreas. Here we report that sweet taste receptors T1R2 and T1R3 are expressed throughout adipogenesis and in adipose tissues. Treatment of mouse and human precursor cells with artificial sweeteners, saccharin and acesulfame potassium, enhanced adipogenesis. Saccharin treatment of 3T3-L1 cells and primary mesenchymal stem cells rapidly stimulated phosphorylation of Akt and downstream targets with functions in adipogenesis such as cAMP-response element-binding protein and FOXO1; however, increased expression of peroxisome proliferator-activated receptor γ and CCAAT/enhancer-binding protein α was not observed until relatively late in differentiation. Saccharin-stimulated Akt phosphorylation at Thr-308 occurred within 5 min, was phosphatidylinositol 3-kinase-dependent, and occurred in the presence of high concentrations of insulin and dexamethasone; phosphorylation of Ser-473 occurred more gradually. Surprisingly, neither saccharin-stimulated adipogenesis nor Thr-308 phosphorylation was dependent on expression of T1R2 and/or T1R3, although Ser-473 phosphorylation was impaired in T1R2/T1R3 double knock-out precursors. In mature adipocytes, artificial sweetener treatment suppressed lipolysis even in the presence of forskolin, and lipolytic responses were correlated with phosphorylation of hormone-sensitive lipase. Suppression of lipolysis by saccharin in adipocytes was also independent of T1R2 and T1R3. These results suggest that some artificial sweeteners have previously uncharacterized metabolic effects on adipocyte differentiation and metabolism and that effects of artificial sweeteners on adipose tissue biology may be largely independent of the classical sweet taste receptors, T1R2 and T1R3. PMID:24068707

Artificial sweeteners stimulate adipogenesis and suppress lipolysis independently of sweet taste receptors.

PubMed

Simon, Becky R; Parlee, Sebastian D; Learman, Brian S; Mori, Hiroyuki; Scheller, Erica L; Cawthorn, William P; Ning, Xiaomin; Gallagher, Katherine; Tyrberg, Björn; Assadi-Porter, Fariba M; Evans, Charles R; MacDougald, Ormond A

2013-11-08

G protein-coupled receptors mediate responses to a myriad of ligands, some of which regulate adipocyte differentiation and metabolism. The sweet taste receptors T1R2 and T1R3 are G protein-coupled receptors that function as carbohydrate sensors in taste buds, gut, and pancreas. Here we report that sweet taste receptors T1R2 and T1R3 are expressed throughout adipogenesis and in adipose tissues. Treatment of mouse and human precursor cells with artificial sweeteners, saccharin and acesulfame potassium, enhanced adipogenesis. Saccharin treatment of 3T3-L1 cells and primary mesenchymal stem cells rapidly stimulated phosphorylation of Akt and downstream targets with functions in adipogenesis such as cAMP-response element-binding protein and FOXO1; however, increased expression of peroxisome proliferator-activated receptor γ and CCAAT/enhancer-binding protein α was not observed until relatively late in differentiation. Saccharin-stimulated Akt phosphorylation at Thr-308 occurred within 5 min, was phosphatidylinositol 3-kinase-dependent, and occurred in the presence of high concentrations of insulin and dexamethasone; phosphorylation of Ser-473 occurred more gradually. Surprisingly, neither saccharin-stimulated adipogenesis nor Thr-308 phosphorylation was dependent on expression of T1R2 and/or T1R3, although Ser-473 phosphorylation was impaired in T1R2/T1R3 double knock-out precursors. In mature adipocytes, artificial sweetener treatment suppressed lipolysis even in the presence of forskolin, and lipolytic responses were correlated with phosphorylation of hormone-sensitive lipase. Suppression of lipolysis by saccharin in adipocytes was also independent of T1R2 and T1R3. These results suggest that some artificial sweeteners have previously uncharacterized metabolic effects on adipocyte differentiation and metabolism and that effects of artificial sweeteners on adipose tissue biology may be largely independent of the classical sweet taste receptors, T1R2 and T1R3.

Involvement of nuclear factor {kappa}B in platelet CD40 signaling

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hachem, Ahmed; Yacoub, Daniel; Centre Hospitalier Universite de Montreal, 264 boul. Rene-Levesque est, Montreal, Quebec, Canada H2X 1P1

Highlights: Black-Right-Pointing-Pointer sCD40L induces TRAF2 association to CD40 and NF-{kappa}B activation in platelets. Black-Right-Pointing-Pointer I{kappa}B{alpha} phosphorylation downstream of CD40L/CD40 signaling is independent of p38 MAPK phosphorylation. Black-Right-Pointing-Pointer I{kappa}B{alpha} is required for sCD40L-induced platelet activation and potentiation of aggregation. -- Abstract: CD40 ligand (CD40L) is a thrombo-inflammatory molecule that predicts cardiovascular events. Platelets constitute the major source of soluble CD40L (sCD40L), which has been shown to potentiate platelet activation and aggregation, in a CD40-dependent manner, via p38 mitogen activated protein kinase (MAPK) and Rac1 signaling. In many cells, the CD40L/CD40 dyad also induces activation of nuclear factor kappa B (NF-{kappa}B). Givenmore » that platelets contain NF-{kappa}B, we hypothesized that it may be involved in platelet CD40 signaling and function. In human platelets, sCD40L induces association of CD40 with its adaptor protein the tumor necrosis factor receptor associated factor 2 and triggers phosphorylation of I{kappa}B{alpha}, which are abolished by CD40L blockade. Inhibition of I{kappa}B{alpha} phosphorylation reverses sCD40L-induced I{kappa}B{alpha} phosphorylation without affecting p38 MAPK phosphorylation. On the other hand, inhibition of p38 MAPK phosphorylation has no effect on I{kappa}B{alpha} phosphorylation, indicating a divergence in the signaling pathway originating from CD40 upon its ligation. In functional studies, inhibition of I{kappa}B{alpha} phosphorylation reverses sCD40L-induced platelet activation and potentiation of platelet aggregation in response to a sub-threshold concentration of collagen. This study demonstrates that the sCD40L/CD40 axis triggers NF-{kappa}B activation in platelets. This signaling pathway plays a critical role in platelet activation and aggregation upon sCD40L stimulation and may represent an important target against thrombo-inflammatory disorders.« less

[Effects of inhibiting the phosphorylation of JNK by absorbed INF-γon the remodeling of nasal mucosa in allergic rhinitis rats].

PubMed

Li, Q; Chen, Y L; Ma, Y Y; Zhang, Y D; Sun, C W; You, C P

2016-07-05

Objective: To study the role of phosphorylated JNK(c-Jun N-terminal kinase) on nasal mucosa remodeling in allergic rhinitis(AR) rats and the influence of IFN-γon IL-1β,JNK and nasal mucosa remodeling. Method: According to random number table,48 Wistar rats were divided into control group(A group),AR group(B group),IFN-γgroup(C group) and triamcinolone acetonide group(D group).The rats in group B,C and D were sensitized and provocated for inducing AR by intraperitoneal injection of ovalbumin(OVA) and Al(OH)₃.Thirty minutes before intranasally challenged,rats in three groups were administrated by instillation of PBS,IFN-γand triamcinolone acetonide into nasal cavities,while the group A rats were administrated by saline solution.Ten rats in each group were selected to enter the final experiment.The density of IL-1βin serum and nasal lavage fluid were tested by ELISA.The mean absorbance (m A ) of phosphorylated JNK and c-Jun were tested by immunohistochemistry.Western Blot detected the P-JNK level in nasal tissue homogenate. Result: The density of IL-1βin serum and nasal lavage fluid in group C and group D were significantly lower than that of group B ( P <0.01).Immunohistochemistry study showed that the protein expression level of phosphorylated JNK and c-Jun of nasal mucosa were significantly increased in group B,but significantly reduced in group C and group D .The mA of phosphorylated JNK and c-Jun in group B were significantly higher than those in the group C and group D( P <0.01).The Western blot showed that the P-JNK of nasal tissue homogenate in group B was higher than that of group C and group D ( P <0.01). Conclusion: The phosphorylation of JNK played an important role in nasal mucosa remodeling.IFN-γcould inhibit the phosphorylation of JNK and reduce the nasal mucosa remodeling.The mechanisms may be achieved through down-regulation of IL-1β. Copyright© by the Editorial Department of Journal of Clinical Otorhinolaryngology Head and Neck Surgery.

Antitumor Activity of Emodin against Pancreatic Cancer Depends on Its Dual Role: Promotion of Apoptosis and Suppression of Angiogenesis

PubMed Central

Chen, Kang-Jie; Tong, Hong-Fei; Wang, Zhao-Hong; Ni, Zhong-Lin; Liu, Hai-Bin; Guo, Hong-Chun; Liu, Dian-Lei

2012-01-01

Background Emodin has been showed to induce apoptosis of pancreatic cancer cells and inhibit tumor growth in our previous studies. This study was designed to investigate whether emodin could inhibit the angiogenesis of pancreatic cancer tissues and its mechanism. Methodology/Principal Finding In accordance with our previous study, emodin inhibited pancreatic cancer cell growth, induced apoptosis, and enhanced the anti-tumor effect of gemcitabine on pancreatic caner cells in vitro and in vivo by inhibiting the activity of NF-κB. Here, for the first time, we demonstrated that emodin inhibited tumor angiogenesis in vitro and in implanted pancreatic cancer tissues, decreased the expression of angiogenesis-associated factors (NF-κB and its regulated factors VEGF, MMP-2, MMP-9, and eNOS), and reduced eNOS phosphorylation, as evidenced by both immunohistochemistry and western blot analysis of implanted tumors. In addition, we found that emodin had no effect on VEGFR expression in vivo. Conclusions/Significance Our results suggested that emodin has potential anti-tumor effect on pancreatic cancer via its dual role in the promotion of apoptosis and suppression of angiogenesis, probably through regulating the expression of NF-κB and NF-κB-regulated angiogenesis-associated factors. PMID:22876305

Transcription factor CREB is involved in CaSR-mediated cytoskeleton gene expression.

PubMed

Huang, Shuaishuai; Ren, Yu; Wang, Ping; Li, Yanyuan; Wang, Xue; Zhuang, Haihui; Fang, Rong; Wang, Yuduo; Liu, Ningsheng; Hehir, Michael; Zhou, Jeff X

2015-03-01

Our previous studies illustrated that a steady increase of intracellular calcium concentration ([Ca2+]i) was important for maintaining microtubules (MTs) rearrangement in apoptotic cells. However, little is known about the effect of calcium sensing receptor (CaSR)-mediated increase in [Ca2+]i on cytoskeleton gene expression. We examined the impact of taxol or CaSR agonist/antagonist on the regulation of [Ca2+]i concentration, cytoskeleton arrangement, phosphorylated CREB and cytoskeleton gene expressions in HeLa cells with dominant negative plasmid of CREB (PM). This study demonstrated that Gdcl3 (a specific CaSR agonist) evoked a rapid increase of [Ca2+]i, formed a rigid bundle of MTs which surrounded the nucleus and decreased the cytoskeleton gene expressions in HeLa cells. These effects were rescued by addition of NPS2390 (a specific CaSR antagonist). Moreover, CaSR activity affected cytoskeleton gene expression through transcription factor CREB. Histoscores of pCREB immunoreactivity in tissues of cervical adenocarcinoma, renal clear cell carcinoma, and diffuse large B-cell lymphoma were markedly increased compared with non malignant tissue. These data demonstrate, for the first time, that CaSR-mediated increase in [Ca2+]i probably modulate cytoskeleton organization and gene expression via transcription factor. © 2014 Wiley Periodicals, Inc.

Cyclic AMP-dependent modification of gonad-selective TAF(II)105 in a human ovarian granulosa cell line.

PubMed

Wu, Yimin; Lu, Yunzhe; Hu, Yanfen; Li, Rong

2005-11-01

In response to gonadotropins, the elevated level of intracellular-cyclic AMP (cAMP) in ovarian granulosa cells triggers an ordered activation of multiple ovarian genes, which in turn promotes various ovarian functions including folliculogenesis and steroidogenesis. Identification and characterization of transcription factors that control ovarian gene expression are pivotal to the understanding of the molecular basis of the tissue-specific gene regulation programs. The recent discovery of the mouse TATA binding protein (TBP)-associated factor 105 (TAF(II)105) as a gonad-selective transcriptional co-activator strongly suggests that general transcription factors such as TFIID may play a key role in regulating tissue-specific gene expression. Here we show that the human TAF(II)105 protein is preferentially expressed in ovarian granulosa cells. We also identified a novel TAF(II)105 mRNA isoform that results from alternative exon inclusion and is predicted to encode a dominant negative mutant of TAF(II)105. Following stimulation by the adenylyl cyclase activator forskolin, TAF(II)105 in granulosa cells undergoes rapid and transient phosphorylation that is dependent upon protein kinase A (PKA). Thus, our work suggests that pre-mRNA processing and post-translational modification represent two important regulatory steps for the gonad-specific functions of human TAF(II)105. Copyright 2005 Wiley-Liss, Inc.

Burn after feeding. An old uncoupler of oxidative phosphorylation is redesigned for the treatment of nonalcoholic fatty liver disease.

PubMed

Fromenty, B

2014-10-01

Uncoupling of oxidative phosphorylation (OXPHOS) in brown adipose tissue can be used by hibernating animals to produce heat at the expense of their fat mass. In a recent work, Dr Shulman et al. generated a liver-targeted derivative of the prototypical OXPHOS uncoupler 2,4-dinitrophenol that alleviated steatosis, hypertriglyceridemia and insulin resistance in several models of nonalcoholic fatty liver disease and type 2 diabetes. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

Engineering of Specific Tissue Inhibitors to Block ADAM Type Metalloprotease-Mediated Mammary Neoplasia

DTIC Science & Technology

2001-07-01

stimulated by KUZ, but not KAMP. SHC or Gabi in COS7 cells was immunoprecipitated with the polyclonal 8 antibody to SHC or Gab1 . Activation of SHC or Gab1 ...was detected in immunoblots as phosphorylation of SHC or Gab1 with anti-phosphotyrosine antibody 4G10. (C) KUZ elevates GPCR-induced Ras activation...decreased the bombesin-dependent phosphorylation of all three isoforms of the adapter protein SHC (Fig. 2 A) and another adapter Gab1 (Fig. 2 B). KUZ

AMPA receptor phosphorylation and recognition memory: learning-related, time-dependent changes in the chick brain following filial imprinting.

PubMed

Solomonia, Revaz O; Meparishvili, Maia; Mikautadze, Ekaterine; Kunelauri, Nana; Apkhazava, David; McCabe, Brian J

2013-04-01

There is strong evidence that a restricted part of the chick forebrain, the intermediate medial mesopallium (IMM), stores information acquired through the learning process of visual imprinting. We have previously demonstrated that at 1 h but not 24 h after imprinting training, a learning-specific increase in the amount of membrane Thr286-autophosphorylated α-calcium/calmodulin-dependent protein kinase II (αCaMKII), and in the proportion of total αCaMKII that is phosphorylated, occurs in the IMM but not in a control brain region, the posterior pole of the nidopallium (PPN). αCaMKII directly phosphorylates Ser831 in the GluA1 subunit of the α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor. In the present study we have inquired whether the learning-related increase in αCaMKII autophosphorylation is followed by changes in the Ser831 phosphorylation of GluA1 (P-GluA1) and in the total amount of this subunit (T-GluA1). Trained chicks together with untrained control chicks were killed either 1 or 24 h after training. Tissue was removed from the IMM together with tissue from the PPN as a control. Amounts of P-GluA1 and T-GluA1 were measured. In the left IMM of the 1 h group the P-GluA1/T-GluA1 ratio increased in a learning-specific way. No learning-related changes were observed in other brain regions at 1 h or in any region 24 h after training. The results indicate that a time- and regionally-dependent, learning-specific increase in GluA1 phosphorylation occurs early in recognition memory formation.

Phosphorylation of GSK-3β and reduction of apoptosis as targets of troxerutin effect on reperfusion injury of diabetic myocardium.

PubMed

Mokhtari, Behnaz; Badalzadeh, Reza; Alihemmati, Alireza; Mohammadi, Mustafa

2015-10-15

Diabetes has various interactions with ischemic heart diseases. Troxerutin, a flavonoid, owns outstanding pharmacological potentials in cardiovascular medicine. The purpose of this study was to investigate the effects of troxerutin on phosphorylation of GSK-3β protein and apoptosis induced by myocardial ischemia-reperfusion injury in healthy and diabetic hearts. Male Wistar rats (n=36, 250-300 g) were randomly divided into four groups: healthy, diabetic, healthy-troxerutin and diabetic-troxerutin. Diabetes was induced by a single injection of streptozotocin (50 mg/kg; ip) and the diabetic period was lasted for ten weeks. Six weeks after induction of diabetes, troxerutin-treated groups received 150 mg/kg/day troxerutin by oral gavage for 4 weeks. The rats' hearts were transferred to the Langendorff apparatus and then subjected to 30 min regional ischemia followed by 45 min reperfusion. Supernatants of the left ventricle were used to measure the levels of cardiac troponin-I (cTnI) by ELISA, total and phosphorylated form of GSK-3β by western blotting and tissue apoptosis by TUNEL assay. Troxerutin administration significantly decreased the cTnI levels in healthy and diabetic groups, as compared to the corresponding controls (P<0.05). In addition, troxerutin significantly increased the level of phosphorylated form and the ratio of phosphorylated to total form of GSK-3β in diabetic and control groups (P<0.05). Tissue apoptosis level and apoptotic index also showed a significant decrease after administration of troxerutin in control and diabetic groups (P<0.05). The findings indicated that the attenuation of GSK-3β activity and subsequent reduction of apoptosis by troxerutin play significant roles in its cardioprotection on reperfusion injuries. Copyright © 2015. Published by Elsevier B.V.

Platelet-derived growth factor-dependent association of the GTPase-activating protein of Ras and Src.

PubMed Central

Schlesinger, T K; Demali, K A; Johnson, G L; Kazlauskas, A

1999-01-01

Here we report that the platelet-derived growth factor beta receptor (betaPDGFR) is not the only tyrosine kinase able to associate with the GTPase-activating protein of Ras (RasGAP). The interaction of non-betaPDGFR kinase(s) with RasGAP was dependent on stimulation with platelet-derived growth factor (PDGF) and seemed to require tyrosine phosphorylation of RasGAP. Because the tyrosine phosphorylation site of RasGAP is in a sequence context that is favoured by the Src homology 2 ('SH2') domain of Src family members, we tested the possibility that Src was the kinase that associated with RasGAP. Indeed, Src interacted with phosphorylated RasGAP fusion proteins; immunodepletion of Src markedly decreased the recovery of the RasGAP-associated kinase activity. Thus PDGF-dependent tyrosine phosphorylation of RasGAP results in the formation of a complex between RasGAP and Src. To begin to address the relevance of these observations, we focused on the consequences of the interaction of Src and RasGAP. We found that a receptor mutant that did not activate Src was unable to efficiently mediate the tyrosine phosphorylation of phospholipase Cgamma (PLCgamma). Taken together, these observations support the following hypothesis. When RasGAP is recruited to the betaPDGFR, it is phosphorylated and associates with Src. Once bound to RasGAP, Src is no longer able to promote the phosphorylation of PLCgamma. This hypothesis offers a mechanistic explanation for our previously published findings that the recruitment of RasGAP to the betaPDGFR attenuates the tyrosine phosphorylation of PLCgamma. Finally, these findings suggest a novel way in which RasGAP negatively regulates signal relay by the betaPDGFR. PMID:10567236

Slack length reduces the contractile phenotype of the Swine carotid artery.

PubMed

Rembold, Christopher M; Garvey, Sean M; Tejani, Ankit D

2013-01-01

Contraction is the primary function of adult arterial smooth muscle. However, in response to vessel injury or inflammation, arterial smooth muscle is able to phenotypically modulate from the contractile state to several 'synthetic' states characterized by proliferation, migration and/or increased cytokine secretion. We examined the effect of tissue length (L) on the phenotype of intact, isometrically held, initially contractile swine carotid artery tissues. Tissues were studied (1) without prolonged incubation at the optimal length for force generation (1.0 Lo, control), (2) with prolonged incubation for 17 h at 1.0 Lo, or (3) with prolonged incubation at slack length (0.6 Lo) for 16 h and then restoration to 1.0 Lo for 1 h. Prolonged incubation at 1.0 Lo minimally reduced the contractile force without substantially altering the mediators of contraction (crossbridge phosphorylation, shortening velocity or stimulated actin polymerization). Prolonged incubation of tissues at slack length (0.6 Lo), despite return of length to 1.0 Lo, substantially reduced contractile force, reduced crossbridge phosphorylation, nearly abolished crossbridge cycling (shortening velocity) and abolished stimulated actin polymerization. These data suggest that (1) slack length treatment significantly alters the contractile phenotype of arterial tissue, and (2) slack length treatment is a model to study acute phenotypic modulation of intact arterial smooth muscle. Copyright © 2013 S. Karger AG, Basel.

Activation of RAS/ERK alone is insufficient to inhibit RXRα function and deplete retinoic acid in hepatocytes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Ai-Guo, E-mail: wangaiguotl@hotmail.com; Song, Ya-Nan; Chen, Jun

2014-09-26

Highlights: • The activation of RAS/ERK is insufficient to inhibit RXRα function and deplete RA. • The retinoid metabolism-related genes are down-regulated by ras oncogene. • The atRA has no effect on preventing hepatic tumorigenesis or curing the developed hepatic nodules. - Abstract: Activation of RAS/ERK signaling pathway, depletion of retinoid, and phosphorylation of retinoid X receptor alpha (RXRα) are frequent events found in liver tumors and thought to play important roles in hepatic tumorigenesis. However, the relationships among them still remained to be elucidated. By exploring the transgenic mouse model of hepatic tumorigenesis induced by liver-specific expression of H-ras12Vmore » oncogene, the activation of RAS/ERK, the mRNA expression levels of retinoid metabolism-related genes, the contents of retinoid metabolites, and phosphorylation of RXRα were determined. RAS/ERK signaling pathway was gradually and significantly activated in hepatic tumor adjacent normal liver tissues (P) and hepatic tumor tissues (T) of H-ras12V transgenic mice compared with normal liver tissues (Wt) of wild type mice. On the contrary, the mRNA expression levels of retinoid metabolism-related genes were significantly reduced in P and T compared with Wt. Interestingly, the retinoid metabolites 9-cis-retinoic acid (9cRA) and all-trans-retinoic acid (atRA), the well known ligands for nuclear transcription factor RXR and retinoic acid receptor (RAR), were significantly decreased only in T compared with Wt and P, although the oxidized polar metabolite of atRA, 4-keto-all-trans-retinoic-acid (4-keto-RA) was significantly decreased in both P and T compared with Wt. To our surprise, the functions of RXRα were significantly blocked only in T compared with Wt and P. Namely, the total protein levels of RXRα were significantly reduced and the phosphorylation levels of RXRα were significantly increased only in T compared with Wt and P. Treatment of H-ras12V transgenic mice at 5-week-old or 5-month-old with atRA had no effect on the prevention of tumorigenesis or cure of developed nodules in liver. These events imply that the depletion of 9cRA and atRA and the inhibition of RXRα function in hepatic tumors involve more complex mechanisms besides the activation of RAS/ERK pathway.« less

Effects of the Combination of the Main Active Components of Astragalus and Panax notoginseng on Inflammation and Apoptosis of Nerve Cell after Cerebral Ischemia-Reperfusion.

PubMed

Huang, Xiao-Ping; Ding, Huang; Lu, Jin-Dong; Tang, Ying-Hong; Deng, Bing-Xiang; Deng, Chang-Qing

2015-01-01

Astragalus and Panax notoginseng are commonly used to treat cardio-cerebrovascular diseases in China and are often combined together to promote curative effect. We speculate that the enhancement of the combination on anticerebral ischemia injury may come from the main active components. The purpose of this work was to probe the effects and mechanisms of Astragaloside IV (the active component of Astragalus) combined with Ginsenoside Rg1, Ginsenoside Rb1, and Notoginsenoside R1 (the active components of P. notoginseng) to antagonize ischemia/reperfusion (I/R) injury via inflammation and apoptosis. C57BL/6 mice were randomly divided into sham, model, Astragaloside IV, Ginsenoside Rg1, Ginsenoside Rb1, Notoginsenoside R1, four active components combination, and Edaravone groups. After administration for 3 days, bilateral common carotid arteries (CCA) were occluded with artery clip for 20[Formula: see text]min followed by reperfusion for 24[Formula: see text]h. Our results showed that the survival rate of nerve cell in hippocampal CA1 decreased while the apoptotic rate increased, and the level of caspase-3 protein in brain tissues was elevated, the expressions of TNF-a, IL-1, and ICAM-1 mRNA as well as phosphorylated nuclear factor kappa B (NF-κB) inhibitor protein α (p-IκBa) in brain tissues were up-regulated, and the nuclear translocation rate of NF-κB was raised. Additionally, the protein expressions of phosphorylated tyrosine kinase 1 (p-JAK1), phosphorylated signal transducer and activator of transcription-1 (p-STAT1), glucose regulated protein 78 (GRP78), caspase-12, and phosphorylated c-Jun N-terminal kinases 1/2 (p-JNK1/2) in brain tissues were also significantly strengthened after I/R for 24 h. All drugs could increase neurocyte survival rate in hippocampal CA1, decrease the apoptotic rate, and inhibit caspase-3 protein expression, in contrast, the effects of four active components combination were better than those of active components alone. In addition, Astragaloside IV and Ginsenoside Rg1 could down-regulate the level of TNF-α, and ICAM-1 mRNA, respectively, Notoginsenoside R1 reduced both TNF-α and ICAM-1 mRNA, and the combination of the 4 effective components had inhibitory effects on the expressions of TNF-α, IL-1β, and ICAM-1 mRNA. Astragaloside IV, Ginsenoside Rg1, Notoginsenoside R1, and 4 effective components combination were able to restrain the phosphorylation of IκBα, and relieve the nuclear translocation rate of NF-κB. Moreover, the effects of the combination are greater than those of active components alone. All drugs could suppress the phosphorylation of JAK1 induced by I/R; meanwhile the expression of p-STAT1 exhibited a decrease in Ginsenoside Rg1 and four active components combination groups. The decreases of p-JAK1 and p-STAT1 in the four active components combination group were more obvious than those in active components alone groups. Astragaloside IV, Ginsenoside Rg1, and Notoginsenoside R1 further augmented GRP78 expression caused by I/R, Notoginsenoside R1 attenuated caspase-12 protein expression, Astragaloside IV and Ginsenoside Rg1 lessened the phosphorylation of JNK1/2, and the four active components combination was capable of up-regulating GRP78 protein while down-regulating the expressions of caspase-12 and p-JNK1/2. Similarly, the effects of the four active components combination were greater than those of effective components alone. These suggested that the combination of the main active components of Astragalus and Panax notoginseng could strengthen protective effects on cerebral ischemia injury via anti-apoptosis and anti-inflammation, and the mechanisms might be associated with restraining the activation of NF-κB and JAK1/STAT1 signal pathways and regulating endoplasmic reticulum stress (ERS) after cerebral ischemia.

Oleanolic acid supplement attenuates liquid fructose-induced adipose tissue insulin resistance through the insulin receptor substrate-1/phosphatidylinositol 3-kinase/Akt signaling pathway in rats

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, Ying; Wang, Jianwei, E-mail: wangjianwei1968@gmail.com; Gu, Tieguang

Oleanolic acid, a triterpenoid contained in more than 1620 plants including various fruits and foodstuffs, has numerous metabolic effects, such as hepatoprotection. However, its underlying mechanisms remain poorly understood. Adipose tissue insulin resistance (Adipo-IR) may contribute to the development and progress of metabolic abnormalities through release of excessive free fatty acids from adipose tissue. This study investigated the effect of oleanolic acid on Adipo-IR. The results showed that supplement with oleanolic acid (25 mg/kg, once daily, by oral gavage) over 10 weeks attenuated liquid fructose-induced increase in plasma insulin concentration and the homeostasis model assessment of insulin resistance (HOMA-IR) indexmore » in rats. Simultaneously, oleanolic acid reversed the increase in the Adipo-IR index and plasma non-esterified fatty acid concentrations during the oral glucose tolerance test assessment. In white adipose tissue, oleanolic acid enhanced mRNA expression of the genes encoding insulin receptor, insulin receptor substrate (IRS)-1 and phosphatidylinositol 3-kinase. At the protein level, oleanolic acid upregulated total IRS-1 expression, suppressed the increased phosphorylated IRS-1 at serine-307, and restored the increased phosphorylated IRS-1 to total IRS-1 ratio. In contrast, phosphorylated Akt to total Akt ratio was increased. Furthermore, oleanolic acid reversed fructose-induced decrease in phosphorylated-Akt/Akt protein to plasma insulin concentration ratio. However, oleanolic acid did not affect IRS-2 mRNA expression. Therefore, these results suggest that oleanolic acid supplement ameliorates fructose-induced Adipo-IR in rats via the IRS-1/phosphatidylinositol 3-kinase/Akt pathway. Our findings may provide new insights into the mechanisms of metabolic actions of oleanolic acid. - Highlights: • Adipose insulin resistance (Adipo-IR) contributes to metabolic abnormalities. • We investigated the effect of oleanolic acid (OA) on adipo-IR in fructose-fed rats. • OA attenuated fructose-induced increase in Adipo-IR index and NEFA concentrations. • OA modulated adipose IRS-1/phosphatidylinositol 3-kinase/Akt signaling. • OA ameliorates Adipo-IR via the IRS-1/PI3K/Akt signaling pathway in rats.« less

TGF-beta and HGF transmit the signals through JNK-dependent Smad2/3 phosphorylation at the linker regions.

PubMed

Mori, Shigeo; Matsuzaki, Koichi; Yoshida, Katsunori; Furukawa, Fukiko; Tahashi, Yoshiya; Yamagata, Hideo; Sekimoto, Go; Seki, Toshihito; Matsui, Hirofumi; Nishizawa, Mikio; Fujisawa, Jun-ichi; Okazaki, Kazuichi

2004-09-23

Although hepatocyte growth factor (HGF) can act synergistically or antagonistically with transforming growth factor-beta (TGF-beta) signaling, molecular mechanism of their crosstalk remains unknown. Using antibodies which selectively distinguished receptor-regulated Smads (R-Smads) phosphorylated at linker regions from those at C-terminal regions, we herein showed that either HGF or TGF-beta treatment of normal stomach-origin cells activated the JNK pathway, thereafter inducing endogenous R-Smads phosphorylation at linker regions. However, the phosphorylation at their C-terminal regions was not induced by HGF treatment. The activated JNK could directly phosphorylate R-Smads in vitro at the same sites that were phosphorylated in response to TGF-beta or HGF in vivo. Thus, the linker regions of R-Smads were the common phosphorylation sites for HGF and TGF-beta signaling pathways. The phosphorylation induced by simultaneous treatment with HGF and TGF-beta allowed R-Smads to associate with Smad4 and to translocate into the nucleus. JNK pathway involved HGF and TGF-beta-mediated infiltration potency since a JNK inhibitor SP600125 caused the reduction of invasive capacity induced by HGF and TGF-beta signals. Moreover, a combined treatment with HGF and TGF-beta led to a potent increase in plasminogen activator inhibitor type 1 transcriptional activity through Smad3 phosphorylation at the linker region. In contrast, HGF treatment reduced TGF-beta-dependent activation of p15INK4B promoter, in which Smad3 phosphorylation at the C-terminal region was involved. In conclusion, HGF and TGF-beta transmit the signals through JNK-mediated R-Smads phosphorylation at linker regions.

Structural basis for Mob1-dependent activation of the core Mst–Lats kinase cascade in Hippo signaling

DOE PAGES

Ni, Lisheng; Zheng, Yonggang; Hara, Mayuko; ...

2015-06-24

The Mst–Lats kinase cascade is central to the Hippo tumor-suppressive pathway that controls organ size and tissue homeostasis. The adaptor protein Mob1 promotes Lats activation by Mst, but the mechanism remains unknown. Here, we show that human Mob1 binds to autophosphorylated docking motifs in active Mst2. This binding enables Mob1 phosphorylation by Mst2. Phosphorylated Mob1 undergoes conformational activation and binds to Lats1. We determine the crystal structures of phospho-Mst2–Mob1 and phospho-Mob1–Lats1 complexes, revealing the structural basis of both phosphorylation-dependent binding events. Further biochemical and functional analyses demonstrate that Mob1 mediates Lats1 activation through dynamic scaffolding and allosteric mechanisms. Thus, Mob1more » acts as a phosphorylation-regulated coupler of kinase activation by virtue of its ability to engage multiple ligands. We propose that stepwise, phosphorylation-triggered docking interactions of nonkinase elements enhance the specificity and robustness of kinase signaling cascades.« less

Indirubin Treatment of Lipopolysaccharide-Induced Mastitis in a Mouse Model and Activity in Mouse Mammary Epithelial Cells.

PubMed

Lai, Jin-Lun; Liu, Yu-Hui; Peng, Yong-Chong; Ge, Pan; He, Chen-Fei; Liu, Chang; Chen, Ying-Yu; Guo, Ai-Zhen; Hu, Chang-Min

2017-01-01

Indirubin is a Chinese medicine extracted from indigo and known to be effective for treating chronic myelogenous leukemia, neoplasia, and inflammatory disease. This study evaluated the in vivo anti-inflammatory activity of indirubin in a lipopolysaccharide- (LPS-) induced mouse mastitis model. The indirubin mechanism and targets were evaluated in vitro in mouse mammary epithelial cells. In the mouse model, indirubin significantly attenuated the severity of inflammatory lesions, edema, inflammatory hyperemia, milk stasis and local tissue necrosis, and neutrophil infiltration. Indirubin significantly decreased myeloperoxidase activity and downregulated the production of tumor necrosis factor- α , interleukin-1 β (IL-1 β ), and IL-6 caused by LPS. In vitro, indirubin inhibited LPS-stimulated expression of proinflammatory cytokines in a dose-dependent manner. It also downregulated LPS-induced toll-like receptor 4 (TLR4) expression and inhibited phosphorylation of LPS-induced nuclear transcription factor-kappa B (NF- κ B) P65 protein and inhibitor of kappa B. In addition to its effect on the NF- κ B signaling pathway, indirubin suppressed the mitogen-activated protein kinase (MAPK) signaling by inhibiting phosphorylation of extracellular signal-regulated kinase (ERK), P38, and c-jun NH2-terminal kinase (JNK). Indirubin improved LPS-induced mouse mastitis by suppressing TLR4 and downstream NF- κ B and MAPK pathway inflammatory signals and might be a potential treatment of mastitis and other inflammatory diseases.

Survival effect of PDGF-CC rescues neurons from apoptosis in both brain and retina by regulating GSK3β phosphorylation

PubMed Central

Tang, Zhongshu; Arjunan, Pachiappan; Lee, Chunsik; Li, Yang; Kumar, Anil; Hou, Xu; Wang, Bin; Wardega, Piotr; Zhang, Fan; Dong, Lijin; Zhang, Yongqing; Zhang, Shi-Zhuang; Ding, Hao; Fariss, Robert N.; Becker, Kevin G.; Lennartsson, Johan; Nagai, Nobuo; Cao, Yihai

2010-01-01

Platelet-derived growth factor CC (PDGF-CC) is the third member of the PDGF family discovered after more than two decades of studies on the original members of the family, PDGF-AA and PDGF-BB. The biological function of PDGF-CC remains largely to be explored. We report a novel finding that PDGF-CC is a potent neuroprotective factor that acts by modulating glycogen synthase kinase 3β (GSK3β) activity. In several different animal models of neuronal injury, such as axotomy-induced neuronal death, neurotoxin-induced neuronal injury, 6-hydroxydopamine–induced Parkinson’s dopaminergic neuronal death, and ischemia-induced stroke, PDGF-CC protein or gene delivery protected different types of neurons from apoptosis in both the retina and brain. On the other hand, loss-of-function assays using PDGF-C null mice, neutralizing antibody, or short hairpin RNA showed that PDGF-CC deficiency/inhibition exacerbated neuronal death in different neuronal tissues in vivo. Mechanistically, we revealed that the neuroprotective effect of PDGF-CC was achieved by regulating GSK3β phosphorylation and expression. Our data demonstrate that PDGF-CC is critically required for neuronal survival and may potentially be used to treat neurodegenerative diseases. Inhibition of the PDGF-CC–PDGF receptor pathway for different clinical purposes should be conducted with caution to preserve normal neuronal functions. PMID:20231377

Mitogen-activated protein kinase inhibition reduces mucin 2 production and mucinous tumor growth.

PubMed

Dilly, Ashok K; Song, Xinxin; Zeh, Herbert J; Guo, Zong S; Lee, Yong J; Bartlett, David L; Choudry, Haroon A

2015-10-01

Excessive accumulation of mucin 2 (MUC2) protein (a gel-forming secreted mucin) within the peritoneal cavity is the major cause of morbidity and mortality in pseudomyxoma peritonei (PMP), a unique mucinous malignancy of the appendix. Mitogen-activated protein kinase (MAPK) signaling pathway is upregulated in PMP and has been shown to modulate MUC2 promoter activity. We hypothesized that targeted inhibition of the MAPK pathway would be a novel, effective, and safe therapeutic strategy to reduce MUC2 production and mucinous tumor growth. We tested RDEA119, a specific MEK1/2 (MAPK extracellular signal-regulated kinase [ERK] kinase) inhibitor, in MUC2-secreting LS174T cells, human PMP explant tissue, and in a unique intraperitoneal murine xenograft model of PMP. RDEA119 reduced ERK1/2 phosphorylation and inhibited MUC2 messenger RNA and protein expression in vitro. In the xenograft model, chronic oral therapy with RDEA119 inhibited mucinous tumor growth in an MAPK pathway-dependent manner and this translated into a significant improvement in survival. RDEA119 downregulated phosphorylated ERK1/2 and nuclear factor κB p65 protein signaling and reduced activating protein 1 (AP1) transcription factor binding to the MUC2 promoter in LS174T cells. This study provides a preclinical rationale for the use of MEK inhibitors to treat patients with PMP. Copyright © 2015 Elsevier Inc. All rights reserved.

Involvement of Phosphorylated "Apis Mellifera" CREB in Gating a Honeybee's Behavioral Response to an External Stimulus

ERIC Educational Resources Information Center

Gehring, Katrin B.; Heufelder, Karin; Feige, Janina; Bauer, Paul; Dyck, Yan; Ehrhardt, Lea; Kühnemund, Johannes; Bergmann, Anja; Göbel, Josefine; Isecke, Marlene; Eisenhardt, Dorothea

2016-01-01

The transcription factor cAMP-response element-binding protein (CREB) is involved in neuronal plasticity. Phosphorylation activates CREB and an increased level of phosphorylated CREB is regarded as an indicator of CREB-dependent transcriptional activation. In honeybees ("Apis mellifera") we recently demonstrated a particular high…

Carbon Monoxide and Nitric Oxide Mediate Cytoskeletal Reorganization in Microvascular Cells via Vasodilator-Stimulated Phosphoprotein Phosphorylation

PubMed Central

Li Calzi, Sergio; Purich, Daniel L.; Chang, Kyung Hee; Afzal, Aqeela; Nakagawa, Takahiko; Busik, Julia V.; Agarwal, Anupam; Segal, Mark S.; Grant, Maria B.

2008-01-01

OBJECTIVE— We examined the effect of the vasoactive agents carbon monoxide (CO) and nitric oxide (NO) on the phosphorylation and intracellular redistribution of vasodilator-stimulated phosphoprotein (VASP), a critical actin motor protein required for cell migration that also controls vasodilation and platelet aggregation. RESEARCH DESIGN AND METHODS— We examined the effect of donor-released CO and NO in endothelial progenitor cells (EPCs) and platelets from nondiabetic and diabetic subjects and in human microvascular endothelial cells (HMECs) cultured under low (5.5 mmol/l) or high (25 mmol/l) glucose conditions. VASP phosphorylation was evaluated using phosphorylation site-specific antibodies. RESULTS— In control platelets, CO selectively promotes phosphorylation at VASP Ser-157, whereas NO promotes phosphorylation primarily at Ser-157 and also at Ser-239, with maximal responses at 1 min with both agents on Ser-157 and at 15 min on Ser-239 with NO treatment. In diabetic platelets, neither agent resulted in VASP phosphorylation. In nondiabetic EPCs, NO and CO increased phosphorylation at Ser-239 and Ser-157, respectively, but this response was markedly reduced in diabetic EPCs. In endothelial cells cultured under low glucose conditions, both CO and NO induced phosphorylation at Ser-157 and Ser-239; however, this response was completely lost when cells were cultured under high glucose conditions. In control EPCs and in HMECs exposed to low glucose, VASP was redistributed to filopodia-like structures following CO or NO exposure; however, redistribution was dramatically attenuated under high glucose conditions. CONCLUSIONS— Vasoactive gases CO and NO promote cytoskeletal changes through site- and cell type–specific VASP phosphorylation, and in diabetes, blunted responses to these agents may lead to reduced vascular repair and tissue perfusion. PMID:18559661

Phosphorylation of Ser136 is critical for potent bone sialoprotein-mediated nucleation of hydroxyapatite crystals.

PubMed

Baht, Gurpreet S; O'Young, Jason; Borovina, Antonia; Chen, Hong; Tye, Coralee E; Karttunen, Mikko; Lajoie, Gilles A; Hunter, Graeme K; Goldberg, Harvey A

2010-05-27

Acidic phosphoproteins of mineralized tissues such as bone and dentin are believed to play important roles in HA (hydroxyapatite) nucleation and growth. BSP (bone sialoprotein) is the most potent known nucleator of HA, an activity that is thought to be dependent on phosphorylation of the protein. The present study identifies the role phosphate groups play in mineral formation. Recombinant BSP and peptides corresponding to residues 1-100 and 133-205 of the rat sequence were phosphorylated with CK2 (protein kinase CK2). Phosphorylation increased the nucleating activity of BSP and BSP-(133-205), but not BSP-(1-100). MS analysis revealed that the major site phosphorylated within BSP-(133-205) was Ser136, a site adjacent to the series of contiguous glutamate residues previously implicated in HA nucleation. The critical role of phosphorylated Ser136 in HA nucleation was confirmed by site-directed mutagenesis and functional analyses. Furthermore, peptides corresponding to the 133-148 sequence of rat BSP were synthesized with or without a phosphate group on Ser136. As expected, the phosphopeptide was a more potent nucleator. The mechanism of nucleation was investigated using molecular-dynamics simulations analysing BSP-(133-148) interacting with the {100} crystal face of HA. Both phosphorylated and non-phosphorylated sequences adsorbed to HA in extended conformations with alternating residues in contact with and facing away from the crystal face. However, this alternating-residue pattern was more pronounced when Ser136 was phosphorylated. These studies demonstrate a critical role for Ser136 phosphorylation in BSP-mediated HA nucleation and identify a unique mode of interaction between the nucleating site of the protein and the {100} face of HA.

Mediation of acetylcholine and substance P induced contractions by myosin light chain phosphorylation in feline colonic smooth muscle.

PubMed

Washabau, Robert J; Holt, David E; Brockman, Daniel J

2002-05-01

To determine the role of myosin light chain phosphorylation in feline colonic smooth muscle contraction. Colonic tissue was obtained from eight 12- to 24-month-old cats. Colonic longitudinal smooth muscle strips were attached to isometric force transducers for measurements of isometric stress. Myosin light chain phosphorylation was determined by isoelectric focusing and sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Stress and phosphorylation were determined following stimulation with ACh or SP, in the absence or presence of a calmodulin antagonist (W-7; 0.1 to 1.0 mM), myosin light chain kinase inhibitor (ML-9; 1 to 10 microM), or extracellular calcium free solutions. Unstimulated longitudinal colonic smooth muscle contained low amounts (6.9+/-3.2%) of phosphorylated myosin light chain. Phosphorylation of the myosin light chains was dose and time dependent with maximal values of 58.5% at 30 seconds of stimulation with 100 microM Ach and 60.2% at 45 seconds of stimulation with 100 nM SP Active isometric stress development closely paralleled phosphorylation of the myosin light chains in ACh- or SP-stimulated muscle. W-7 and ML-9 dose dependently inhibited myosin light chain phosphorylation and isometric stress development associated with ACh or SP stimulation. Removal of extracellular calcium inhibited myosin light chain phosphorylation and isometric stress development in ACh-stimulated smooth muscle. Feline longitudinal colonic smooth muscle contraction is calcium-, calmodulin-, and myosin light chain kinase-dependent. Myosin light chain phosphorylation is necessary for the initiation of contraction in feline longitudinal colonic smooth muscle. These findings may prove useful in determining the biochemical and molecular defects that accompany feline colonic motility disorders.

Redox signaling in pathophysiology of hypertension.

PubMed

Majzunova, Miroslava; Dovinova, Ima; Barancik, Miroslav; Chan, Julie Y H

2013-09-18

Reactive oxygen species (ROS) are products of normal cellular metabolism and derive from various sources in different cellular compartments. Oxidative stress resultant from imbalance between ROS generation and antioxidant defense mechanisms is important in pathogenesis of cardiovascular diseases, such as hypertension, heart failure, atherosclerosis, diabetes, and cardiac hypertrophy. In this review we focus on hypertension and address sources of cellular ROS generation, mechanisms involved in regulation of radical homeostasis, superoxide dismutase isoforms in pathophysiology of hypertension; as well as radical intracellular signaling and phosphorylation processes in proteins of the affected cardiovascular tissues. Finally, we discuss the transcriptional factors involved in redox-sensitive gene transcription and antioxidant response, as well as their roles in hypertension.

Redox signaling in pathophysiology of hypertension

PubMed Central

2013-01-01

Reactive oxygen species (ROS) are products of normal cellular metabolism and derive from various sources in different cellular compartments. Oxidative stress resultant from imbalance between ROS generation and antioxidant defense mechanisms is important in pathogenesis of cardiovascular diseases, such as hypertension, heart failure, atherosclerosis, diabetes, and cardiac hypertrophy. In this review we focus on hypertension and address sources of cellular ROS generation, mechanisms involved in regulation of radical homeostasis, superoxide dismutase isoforms in pathophysiology of hypertension; as well as radical intracellular signaling and phosphorylation processes in proteins of the affected cardiovascular tissues. Finally, we discuss the transcriptional factors involved in redox-sensitive gene transcription and antioxidant response, as well as their roles in hypertension. PMID:24047403

Caffeine inhibition of glycogen phosphorylase from Mytilus galloprovincialis mantle tissue.

PubMed

San Juan Serrano, F; Sánchez López, J L; García Martín, L O

1995-09-01

A different caffeine inhibition of both phosphorylated and unphosphorylated forms of glycogen phosphorylase from Mytilus mantle has been demonstrated. Caffeine increases the allosteric constant of phosphorylase b 30-fold, acting as an allosteric inhibitor (nH = 2) of mixed type with respect to inorganic phosphate (Pi) and AMP, and of single competitive type with respect to glycogen. The Mytilus phosphorylated form is also caffeine inhibited through competitive inhibition in relation to Pi and glycogen. In this case, the inhibitor does not modify the allosteric constant (near 2), neither does it display allosteric effects (nH = 1). The results demonstrate the notable modification of the nucleotide site promoted by the phosphorylation process and the existence of a functional inhibitory nucleoside site in Mytilus phosphorylase.

Myosin Binding Protein-C Slow Phosphorylation is Altered in Duchenne Dystrophy and Arthrogryposis Myopathy in Fast-Twitch Skeletal Muscles.

PubMed

Ackermann, Maegen A; Ward, Christopher W; Gurnett, Christina; Kontrogianni-Konstantopoulos, Aikaterini

2015-08-19

Myosin Binding Protein-C slow (sMyBP-C), encoded by MYBPC1, comprises a family of regulatory proteins of skeletal muscles that are phosphorylated by PKA and PKC. MYBPC1 missense mutations are linked to the development of Distal Arthrogryposis-1 (DA-1). Although structure-function details for this myopathy are evolving, function is undoubtedly driven by sequence variations and post-translational modifications in sMyBP-C. Herein, we examined the phosphorylation profile of sMyBP-C in mouse and human fast-twitch skeletal muscles. We used Flexor Digitorum Brevis (FDB) isolated from young (~2-months old) and old (~14-months old) wild type and mdx mice, and human Abductor Hallucis (AH) and gastrocnemious muscles carrying the DA-1 mutations. Our results indicate both constitutive and differential phosphorylation of sMyBP-C in aged and diseased muscles. We report a 7-35% reduction in the phosphorylation levels of select sites in old wild type and young or old mdx FDB mouse muscles, compared to young wild type tissue. Similarly, we observe a 30-70% decrease in the phosphorylation levels of all PKA and PKC phospho-sites in the DA-1 AH, but not gastrocnemius, muscle. Overall, our studies show that the phosphorylation pattern of sMyBP-C is differentially regulated in response to age and disease, suggesting that phosphorylation plays important roles in these processes.

Hormonal regulation of circulating insulin-like growth factor-binding protein-1 phosphorylation status.

PubMed

Westwood, M; Gibson, J M; Williams, A C; Clayton, P E; Hamberg, O; Flyvbjerg, A; White, A

1995-12-01

Insulin-like growth factor (IGF)-binding protein-1 (IGFBP-1) normally circulates as a single, highly phosphorylated species. However, IGFBP-1 phosphorylation status can be altered, such as in pregnancy where non- and lesser phosphorylated isoforms are also present. We have examined how hormonal regulators of circulating IGFBP-1 influence its phosphorylation status and, hence, its ability to modulate IGF activity. In response to insulin-induced hypoglycemia (0.2 U/kg, iv), an increase in the highly phosphorylated isoform was observed after 5 h [16 (range, 11.5-35.5) to 77 (range, 63-250) microgram/L; 4.8-fold increase; P = 0.009], but no non- or lesser phosphorylated variants could be detected. Glucagon (1 mg, sc), increased IGFBP-1 from 27 (range, 13-36.5) to 112 (range, 100.5-129) micrograms/L (4.1-fold increase; P = 0.009) after 90 min despite preceding insulin concentrations of more than 500 pmol/L, but again the IGFBP-1 remained in the highly phosphorylated form. Regulation of IGFBP-1 phosphorylation by sex steroids was studied by comparing women receiving a combined oral contraceptive with women on no medication. Although plasma IGFBP-1 levels were significantly elevated in the treatment group [120 (range, 97.5-237.5) vs. 52 (range, 38-70) micrograms/L; P < 0.004], there was no difference in the form of IGFBP-1 present. The acute effect of somatostatin (500 micrograms/h) on IGFBP-1 phosphorylation status was also studied. Somatostatin only increased the phosphoform characteristic of normal subjects; the appearance of non- or lesser phosphorylated variants was not induced. The effect of rhIGF-I (80 or 120 micrograms, sc) on plasma IGFBP-1 was studied in three subjects with Laron's syndrome. A transient increase in the highly phosphorylated isoform of IGFBP-1 was noted; there was no rise in the non- and lesser phosphorylated isoforms also found in the plasma of Laron's syndrome subjects. These data suggest that only the highly phosphorylated species of IGFBP-1 is under hormonal control; regulation of the non- and lesser phosphorylated variants remains to be determined.

The procurement, storage, and quality assurance of frozen blood and tissue biospecimens in pathology, biorepository, and biobank settings

PubMed Central

Shabihkhani, Maryam; Lucey, Gregory M.; Wei, Bowen; Mareninov, Sergey; Lou, Jerry J.; Vinters, Harry V.; Singer, Elyse J.; Cloughesy, Timothy F.; Yong, William H.

2014-01-01

Well preserved frozen biospecimens are ideal for evaluating the genome, transcriptome, and proteome. While papers reviewing individual aspects of frozen biospecimens are available, we present a current overview of experimental data regarding procurement, storage, and quality assurance that can inform the handling of frozen biospecimens. Frozen biospecimen degradation can be influenced by factors independent of the collection methodology including tissue type, premortem agonal changes, and warm ischemia time during surgery. Rapid stabilization of tissues by snap freezing immediately can mitigate artifactually altered gene expression and, less appreciated, protein phosphorylation profiles. Collection protocols may be adjusted for specific tissue types as cellular ischemia tolerance varies widely. If data is not available for a particular tissue type, a practical goal is snap freezing within 20 minutes. Tolerance for freeze-thaw events is also tissue type dependent. Tissue storage at −80°C can preserve DNA and protein for years but RNA can show degradation at 5 years. For −80°C freezers, aliquots frozen in RNAlater or similar RNA stabilizing solutions is a consideration. It remains unresolved as to whether storage at −150°C provides significant advantages relative to −80°C. Histologic quality assurance of tissue biospecimens is typically performed at the time of surgery but should also be conducted on the aliquot to be distributed because of tissue heterogeneity. Biobanking protocols for blood and its components are highly dependent on intended use and multiple collection tube types may be needed. Additional quality assurance testing should be dictated by the anticipated downstream applications. PMID:24424103

Differential phosphorylations of Spi-B and Spi-1 transcription factors.

PubMed

Mao, C; Ray-Gallet, D; Tavitian, A; Moreau-Gachelin, F

1996-02-15

Spi-1/PU-1 and Spi-B are hematopoietic transcription factors, which, in vitro, display similar affinities for DNA target sequences containing the consensus binding site 5'-GGAA-3'. While the role of Spi-1 in the transcriptional regulation of B cell and myeloid specific genes has been largely demonstrated, the biological function of Spi-B still remains to be elucidated. Since Spi-B and Spi-1 are very divergent in their transactivator domain, these domains might acquire functional specificity in vivo by interacting with different co-factors and/or by undergoing different phosphorylations. First, we observed that casein kinase II phosphorylates Spi-B as well as Spi-1, in vitro. Then, by affinity chromatographies and in vitro kinase assays with fusion proteins between glutathione-S-transferase and the transactivator domain of Spi-B, two kinases were identified on their ability to interact and phosphorylate this domain; the MAP kinase ERK1 and the stress activated protein kinase JNK1. The Threonine 56 was defined as the ERK1 phosphorylation site by using phosphoamino-acid analyses and a Spi-B mutant version with the substitution T56 to A56. Strikingly, ERK1 failed to phosphorylate Spi-1, in vitro, whereas JNK1, like CK II, phosphorylated Spi-B and Spi-1. In addition, other purified Spi-B-kinase activities, unidentified as yet, display similar specificity than ERK1 for Spi-B versus Spi-1. Furthermore, the evident interaction of pRb protein with the transactivator domain of Spi-B in an unphosphorylated state disappeared when this domain was first phosphorylated in vitro either by ERK1 or by the purified Spi-B-kinase activities. Our data revealed multiple phosphorylation sites within Spi-B whose some of them appeared specific for Spi-B versus Spi-1 and which may account for differential regulation of their activities.

GSK3β phosphorylates newly identified site in the proline-alanine-rich region of cardiac myosin-binding protein C and alters cross-bridge cycling kinetics in human: short communication.

PubMed

Kuster, Diederik W D; Sequeira, Vasco; Najafi, Aref; Boontje, Nicky M; Wijnker, Paul J M; Witjas-Paalberends, E Rosalie; Marston, Steven B; Dos Remedios, Cristobal G; Carrier, Lucie; Demmers, Jeroen A A; Redwood, Charles; Sadayappan, Sakthivel; van der Velden, Jolanda

2013-02-15

Cardiac myosin-binding protein C (cMyBP-C) regulates cross-bridge cycling kinetics and, thereby, fine-tunes the rate of cardiac muscle contraction and relaxation. Its effects on cardiac kinetics are modified by phosphorylation. Three phosphorylation sites (Ser275, Ser284, and Ser304) have been identified in vivo, all located in the cardiac-specific M-domain of cMyBP-C. However, recent work has shown that up to 4 phosphate groups are present in human cMyBP-C. To identify and characterize additional phosphorylation sites in human cMyBP-C. Cardiac MyBP-C was semipurified from human heart tissue. Tandem mass spectrometry analysis identified a novel phosphorylation site on serine 133 in the proline-alanine-rich linker sequence between the C0 and C1 domains of cMyBP-C. Unlike the known sites, Ser133 was not a target of protein kinase A. In silico kinase prediction revealed glycogen synthase kinase 3β (GSK3β) as the most likely kinase to phosphorylate Ser133. In vitro incubation of the C0C2 fragment of cMyBP-C with GSK3β showed phosphorylation on Ser133. In addition, GSK3β phosphorylated Ser304, although the degree of phosphorylation was less compared with protein kinase A-induced phosphorylation at Ser304. GSK3β treatment of single membrane-permeabilized human cardiomyocytes significantly enhanced the maximal rate of tension redevelopment. GSK3β phosphorylates cMyBP-C on a novel site, which is positioned in the proline-alanine-rich region and increases kinetics of force development, suggesting a noncanonical role for GSK3β at the sarcomere level. Phosphorylation of Ser133 in the linker domain of cMyBP-C may be a novel mechanism to regulate sarcomere kinetics.

The Clk/Sty protein kinase phosphorylates SR splicing factors and regulates their intranuclear distribution.

PubMed Central

Colwill, K; Pawson, T; Andrews, B; Prasad, J; Manley, J L; Bell, J C; Duncan, P I

1996-01-01

Mammalian Clk/Sty is the prototype for a family of dual specificity kinases (termed LAMMER kinases) that have been conserved in evolution, but whose physiological substrates are unknown. In a yeast two-hybrid screen, the Clk/Sty kinase specifically interacted with RNA binding proteins, particularly members of the serine/arginine-rich (SR) family of splicing factors. Clk/Sty itself has an serine/arginine-rich non-catalytic N-terminal region which is important for its association with SR splicing factors. In vitro, Clk/Sty efficiently phosphorylated the SR family member ASF/SF2 on serine residues located within its serine/arginine-rich region (the RS domain). Tryptic phosphopeptide mapping demonstrated that the sites on ASF/SF2 phosphorylated in vitro overlap with those phosphorylated in vivo. Immunofluorescence studies showed that a catalytically inactive form of Clk/Sty co-localized with SR proteins in nuclear speckles. Overexpression of the active Clk/Sty kinase caused a redistribution of SR proteins within the nucleus. These results suggest that Clk/Sty kinase directly regulates the activity and compartmentalization of SR splicing factors. Images PMID:8617202

Vitamin C restores healthy aging in a mouse model for Werner syndrome

PubMed Central

Massip, Laurent; Garand, Chantal; Paquet, Eric R.; Cogger, Victoria C.; O’Reilly, Jennifer N.; Tworek, Leslee; Hatherell, Avril; Taylor, Carla G.; Thorin, Eric; Zahradka, Peter; Le Couteur, David G.; Lebel, Michel

2013-01-01

Werner syndrome (WS) is a premature aging disorder caused by mutations in a RecQ-like DNA helicase. Mice lacking the helicase domain of the WRN homologue exhibit many phenotypic features of WS, including a prooxidant status and a shorter mean life span compared to wild-type animals. Here, we show that Wrn mutant mice also develop premature liver sinusoidal endothelial defenestration along with inflammation and metabolic syndrome. Vitamin C supplementation rescued the shorter mean life span of Wrn mutant mice and reversed several age-related abnormalities in adipose tissues and liver endothelial defenestration, genomic integrity, and inflammatory status. At the molecular level, phosphorylation of age-related stress markers like Akt kinase-specific substrates and the transcription factor NF-κB, as well as protein kinase Cδ and Hif-1α transcription factor levels, which are increased in the liver of Wrn mutants, were normalized by vitamin C. Vitamin C also increased the transcriptional regulator of lipid metabolism PPARα. Finally, microarray and gene set enrichment analyses on liver tissues revealed that vitamin C decreased genes normally up-regulated in human WS fibroblasts and cancers, and it increased genes involved in tissue injury response and adipocyte dedifferentiation in obese mice. Vitamin C did not have such effect on wild-type mice. These results indicate that vitamin C supplementation could be beneficial for patients with WS. PMID:19741171

MTBP inhibits the Erk1/2-Elk-1 signaling in hepatocellular carcinoma

PubMed Central

Ranjan, Atul; Iyer, Swathi V.; Ward, Christopher; Link, Tim; Diaz, Francisco J.; Dhar, Animesh; Tawfik, Ossama W.; Weinman, Steven A.; Azuma, Yoshiaki; Izumi, Tadahide; Iwakuma, Tomoo

2018-01-01

Hepatocellular carcinoma (HCC) is one of the most common cancers worldwide, and the prognosis of HCC patients, especially those with metastasis, remains extremely poor. This is partly due to unclear molecular mechanisms underlying HCC metastasis. Our previous study indicates that MDM2 Binding Protein (MTBP) suppresses migration and metastasis of HCC cells. However, signaling pathways regulated by MTBP remain unknown. To identify metastasis-associated signaling pathways governed by MTBP, we have performed unbiased luciferase reporter-based signal array analyses and found that MTBP suppresses the activity of the ETS-domain transcription factor Elk-1, a downstream target of Erk1/2 MAP kinases. MTBP also inhibits phosphorylation of Elk-1 and decreases mRNA expression of Elk-1 target genes. Reduced Elk-1 activity is caused by inhibited nuclear translocation of phosphorylated Erk1/2 (p-Erk) by MTBP and subsequent inhibition of Elk-1 phosphorylation. We also reveal that MTBP inhibits the interaction of p-Erk with importin-7/RanBP7 (IPO7), an importin family member which shuttles p-Erk into the nucleus, by binding to IPO7. Moreover, high levels of MTBP in human HCC tissues are correlated with cytoplasmic localization of p-Erk1/2. Our study suggests that MTBP suppresses metastasis, at least partially, by down-modulating the Erk1/2-Elk-1 signaling pathway, thus identifying a novel regulatory mechanism of HCC metastasis by regulating the subcellular localization of p-Erk. PMID:29765550

Phosphoregulation of the C. elegans cadherin–catenin complex

PubMed Central

Callaci, Sandhya; Morrison, Kylee; Shao, Xiangqiang; Schuh, Amber L.; Wang, Yueju; Yates, John R.; Hardin, Jeff; Audhya, Anjon

2015-01-01

Adherens junctions play key roles in mediating cell–cell contacts during tissue development. In Caenorhabditis elegans embryos, the cadherin–catenin complex (CCC), composed of the classical cadherin HMR-1 and members of three catenin families, HMP-1, HMP-2 and JAC-1, is necessary for normal blastomere adhesion, gastrulation, ventral enclosure of the epidermis and embryo elongation. Disruption of CCC assembly or function results in embryonic lethality. Previous work suggests that components of the CCC are subject to phosphorylation. However, the identity of phosphorylated residues in CCC components and their contributions to CCC stability and function in a living organism remain speculative. Using mass spectrometry, we systematically identify phosphorylated residues in the essential CCC subunits HMR-1, HMP-1 and HMP-2 in vivo. We demonstrate that HMR-1/cadherin phosphorylation occurs on three sites within its β-catenin binding domain that each contributes to CCC assembly on lipid bilayers. In contrast, phosphorylation of HMP-2/β-catenin inhibits its association with HMR-1/cadherin in vitro, suggesting a role in CCC disassembly. Although HMP-1/α-catenin is also phosphorylated in vivo, phosphomimetic mutations do not affect its ability to associate with other CCC components or interact with actin in vitro. Collectively, our findings support a model in which distinct phosphorylation events contribute to rapid CCC assembly and disassembly, both of which are essential for morphogenetic rearrangements during development. PMID:26443865

Tissue plasminogen activator mediates amyloid-induced neurotoxicity via Erk1/2 activation

PubMed Central

Medina, Manel G; Ledesma, Maria Dolores; Domínguez, Jorge E; Medina, Miguel; Zafra, Delia; Alameda, Francesc; Dotti, Carlos G; Navarro, Pilar

2005-01-01

Tissue plasminogen activator (tPA) is the main activator of plasminogen into plasmin in the brain where it may have beneficial roles but also neurotoxic effects that could be plasmin dependent or not. Little is known about the substrates and pathways that mediate plasmin-independent tPA neurotoxicity. Here we show in primary hippocampal neurons that tPA promotes a catalytic-independent activation of the extracellular regulated kinase (Erk)1/2 signal transduction pathway through the N-methyl-D-aspartate receptor, G-proteins and protein kinase C. This results in GSK3 activation in a process that requires de novo synthesis of proteins, and leads to tau aberrant phosphorylation, microtubule destabilization and apoptosis. Similar effects are produced by amyloid aggregates in a tPA-dependent manner, as demonstrated by pharmacological treatments and in wt and tPA−/− mice neurons. Consistently, in Alzheimer's disease (AD) patients' brains, high levels of tPA colocalize with amyloid-rich areas, activated Erk1/2 and phosphorylated tau. This is the first demonstration of an intracellular pathway by which tPA triggers kinase activation, tau phosphorylation and neurotoxicity, suggesting a key role for this molecule in AD pathology. PMID:15861134

Plasma Rich in Growth Factors Induces Cell Proliferation, Migration, Differentiation, and Cell Survival of Adipose-Derived Stem Cells

PubMed Central

Mellado-López, Maravillas; Griffeth, Richard J.; Meseguer-Ripolles, Jose; García, Montserrat

2017-01-01

Adipose-derived stem cells (ASCs) are a promising therapeutic alternative for tissue repair in various clinical applications. However, restrictive cell survival, differential tissue integration, and undirected cell differentiation after transplantation in a hostile microenvironment are complications that require refinement. Plasma rich in growth factors (PRGF) from platelet-rich plasma favors human and canine ASC survival, proliferation, and delaying human ASC senescence and autophagocytosis in comparison with serum-containing cultures. In addition, canine and human-derived ASCs efficiently differentiate into osteocytes, adipocytes, or chondrocytes in the presence of PRGF. PRGF treatment induces phosphorylation of AKT preventing ASC death induced by lethal concentrations of hydrogen peroxide. Indeed, AKT inhibition abolished the PRGF apoptosis prevention in ASC exposed to 100 μM of hydrogen peroxide. Here, we show that canine ASCs respond to PRGF stimulus similarly to the human cells regarding cell survival and differentiation postulating the use of dogs as a suitable translational model. Overall, PRGF would be employed as a serum substitute for mesenchymal stem cell amplification to improve cell differentiation and as a preconditioning agent to prevent oxidative cell death. PMID:29270200

Role of Helicobacter pylori virulence factor cytotoxin-associated gene A in gastric mucosa-associated lymphoid tissue lymphoma.

PubMed

Wang, Hong-Ping; Zhu, Yong-Liang; Shao, Wei

2013-12-07

Helicobacter pylori (H. pylori) infection might initiate and contribute to the progression of lymphoma from gastric mucosa-associated lymphoid tissue (MALT). Increasing evidence shows that eradication of H. pylori with antibiotic therapy can lead to regression of gastric MALT lymphoma and can result in a 10-year sustained remission. The eradication of H. pylori is the standard care for patients with gastric MALT lymphoma. Cytotoxin-associated gene A (CagA) protein, one of the most extensively studied H. pylori virulence factors, is strongly associated with the gastric MALT lymphoma. CagA possesses polymorphisms according to its C-terminal structure and displays different functions among areas and races. After being translocated into B lymphocytes via type IV secretion system, CagA deregulates intracellular signaling pathways in both tyrosine phosphorylation-dependent and -independent manners and/or some other pathways, and thereby promotes lymphomagenesis. A variety of proteins including p53 and protein tyrosine phosphatases-2 are involved in the malignant transformation induced by CagA. Mucosal inflammation is the foundational mechanism underlying the occurrence and development of gastric MALT lymphoma. © 2013 Baishideng Publishing Group Co., Limited. All rights reserved.

Tissue Strain Reorganizes Collagen With a Switchlike Response That Regulates Neuronal Extracellular Signal-Regulated Kinase Phosphorylation In Vitro: Implications for Ligamentous Injury and Mechanotransduction

PubMed Central

Zhang, Sijia; Cao, Xuan; Stablow, Alec M.; Shenoy, Vivek B.; Winkelstein, Beth A.

2016-01-01

Excessive loading of ligaments can activate the neural afferents that innervate the collagenous tissue, leading to a host of pathologies including pain. An integrated experimental and modeling approach was used to define the responses of neurons and the surrounding collagen fibers to the ligamentous matrix loading and to begin to understand how macroscopic deformation is translated to neuronal loading and signaling. A neuron-collagen construct (NCC) developed to mimic innervation of collagenous tissue underwent tension to strains simulating nonpainful (8%) or painful ligament loading (16%). Both neuronal phosphorylation of extracellular signal-regulated kinase (ERK), which is related to neuroplasticity (R2 ≥ 0.041; p ≤ 0.0171) and neuronal aspect ratio (AR) (R2 ≥ 0.250; p < 0.0001), were significantly correlated with tissue-level strains. As NCC strains increased during a slowly applied loading (1%/s), a “switchlike” fiber realignment response was detected with collagen reorganization occurring only above a transition point of 11.3% strain. A finite-element based discrete fiber network (DFN) model predicted that at bulk strains above the transition point, heterogeneous fiber strains were both tensile and compressive and increased, with strains in some fibers along the loading direction exceeding the applied bulk strain. The transition point identified for changes in collagen fiber realignment was consistent with the measured strain threshold (11.7% with a 95% confidence interval of 10.2–13.4%) for elevating ERK phosphorylation after loading. As with collagen fiber realignment, the greatest degree of neuronal reorientation toward the loading direction was observed at the NCC distraction corresponding to painful loading. Because activation of neuronal ERK occurred only at strains that produced evident collagen fiber realignment, findings suggest that tissue strain-induced changes in the micromechanical environment, especially altered local collagen fiber kinematics, may be associated with mechanotransduction signaling in neurons. PMID:26549105

Preanalytical variables and phosphoepitope expression in FFPE tissue: quantitative epitope assessment after variable cold ischemic time.

PubMed

Vassilakopoulou, Maria; Parisi, Fabio; Siddiqui, Summar; England, Allison M; Zarella, Elizabeth R; Anagnostou, Valsamo; Kluger, Yuval; Hicks, David G; Rimm, David L; Neumeister, Veronique M

2015-03-01

Individualized targeted therapies for cancer patients require accurate and reproducible assessment of biomarkers to be able to plan treatment accordingly. Recent studies have shown highly variable effects of preanalytical variables on gene expression profiling and protein levels of different tissue types. Several publications have described protein degradation of tissue samples as a direct result of delay of formalin fixation of the tissue. Phosphorylated proteins are more labile and epitope degradation can happen within 30 min of cold ischemic time. To address this issue, we evaluated the change in antigenicity of a series of phosphoproteins in paraffin-embedded samples from breast tumors as a function of time to formalin fixation. A tissue microarray consisting of 93 breast cancer specimens with documented time-to-fixation was used to evaluate changes in antigenicity of 12 phosphoepitopes frequently used in research settings as a function of cold ischemic time. Analysis was performed in a quantitative manner using the AQUA technology for quantitative immunofluorescence. For each marker, least squares univariate linear regression was performed and confidence intervals were computed using bootstrapping. The majority of the epitopes tested revealed changes in expression levels with increasing time to formalin fixation. Some phosphorylated proteins, such as phospho-HSP27 and phospho-S6 RP, involved in post-translational modification and stress response pathways increased in expression or phosphorylation levels. Others (like phospho-AKT, phosphor-ERK1/2, phospho-Tyrosine, phospho-MET, and others) are quite labile and loss of antigenicity can be reported within 1-2 h of cold ischemic time. Therefore specimen collection should be closely monitored and subjected to quality control measures to ensure accurate measurement of these epitopes. However, a few phosphoepitopes (like phospho-JAK2 and phospho-ER) are sufficiently robust for routine usage in companion diagnostic testing.

Adenosine triphosphate as a molecular mediator of the vascular response to injury.

PubMed

Guth, Christy M; Luo, Weifung; Jolayemi, Olukemi; Chadalavada, Kalyan S; Komalavilas, Padmini; Cheung-Flynn, Joyce; Brophy, Colleen M

2017-08-01

Human saphenous veins used for arterial bypass undergo stretch injury at the time of harvest and preimplant preparation. Vascular injury promotes intimal hyperplasia, the leading cause of graft failure, but the molecular events leading to this response are largely unknown. This study investigated adenosine triphosphate (ATP) as a potential molecular mediator in the vascular response to stretch injury, and the downstream effects of the purinergic receptor, P2X7R, and p38 MAPK activation. A subfailure stretch rat aorta model was used to determine the effect of stretch injury on release of ATP and vasomotor responses. Stretch-injured tissues were treated with apyrase, the P2X7R antagonist, A438079, or the p38 MAPK inhibitor, SB203580, and subsequent contractile forces were measured using a muscle bath. An exogenous ATP (eATP) injury model was developed and the experiment repeated. Change in p38 MAPK phosphorylation after stretch and eATP tissue injury was determined using Western blotting. Noninjured tissue was incubated in the p38 MAPK activator, anisomycin, and subsequent contractile function and p38 MAPK phosphorylation were analyzed. Stretch injury was associated with release of ATP. Contractile function was decreased in tissue subjected to subfailure stretch, eATP, and anisomycin. Contractile function was restored by apyrase, P2X7R antagonism, and p38-MAPK inhibition. Stretch, eATP, and anisomycin-injured tissue demonstrated increased phosphorylation of p38 MAPK. Taken together, these data suggest that the vascular response to stretch injury is associated with release of ATP and activation of the P2X7R/P38 MAPK pathway, resulting in contractile dysfunction. Modulation of this pathway in vein grafts after harvest and before implantation may reduce the vascular response to injury. Copyright © 2017 Elsevier Inc. All rights reserved.

Changes of the body functions during long-term hypokinesia

NASA Technical Reports Server (NTRS)

Kovalenko, Y. A.; Popkov, V. L.; Kondratev, Y. I.; Mailyan, E. S.; Galushko, Y. S.; Prokhonchukov, A. A.; Kazaryan, V. A.; Morozova, R. S.; Serova, L. V.; Potapov, A. N.

1980-01-01

Prolonged hypokinesis (100-170 days) studied in 2000 rats kept in cages limiting their mobility provoked considerable changes in the gaseous and energetic metabolism: an elevation of the total gaseous metabolism and of the rate of O2 requirement by the muscles (in the late periods of hypokinesis) and a change in the intensity of tissue respiration of the liver and myocardium. There also proved to be a reduction in the level of phosphorylation and separation of oxidative phosphorylation in the myocardium, liver, and partially in the skeletal muscle. Prolonged hypokinesia led to changes in tissue metabolism: a disturbance of development of the animals, a marked delay and an increase in the weight of the organism and the muscular system, and disturbances of the mineral and protein metabolism. Prolonged hypokinesis also lead to exhaustion of the hypothalamus-hypophysis-adrenal cortex system.

Constitutive hypophosphorylation of extracellular signal-regulated kinases-1/2 and down-regulation of c-Jun in human gastric adenocarcinoma

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wu, William Ka Kei; Department of Medicine and Therapeutics, Chinese University of Hong Kong, Hong Kong; Institute of Digestive Diseases, Chinese University of Hong Kong, Hong Kong

2008-08-22

Hyperphosphorylation of extracellular signal-regulated protein kinases-1/2 (ERK1/2) is known to promote cancer cell proliferation. We therefore investigated the constitutive phosphorylation levels of ERK1/2 and the expression of its downstream targets c-Fos, c-Jun, and cyclooxygenase-2 (COX-2) in biopsied human gastric cancer tissues. Results showed that ERK1/2 phosphorylation and c-Jun expression were significantly lowered in gastric cancer compared with the non-cancer adjacent tissues. The expression of c-Fos, however, was not altered while COX-2 was significantly up-regulated. To conclude, we demonstrate that hypophosphorylation of ERK1/2 may occur in gastric cancer. Such discovery may have implication in the application of pathway-directed therapy for thismore » malignant disease.« less

Complementary IMAC enrichment methods for HLA-associated phosphopeptide identification by mass spectrometry

PubMed Central

Abelin, Jennifer G; Trantham, Paisley D; Penny, Sarah A; Patterson, Andrea M; Ward, Stephen T; Hildebrand, William H; Cobbold, Mark; Bai, Dina L; Shabanowitz, Jeffrey; Hunt, Donald F

2015-01-01

Phosphorylation events within cancer cells often become dysregulated, leading to oncogenic signaling and abnormal cell growth. Phosphopeptides derived from aberrantly phosphorylated proteins that are presented on tumors and not on normal tissues by human leukocyte antigen (HLA) class I molecules are promising candidates for future cancer immunotherapies, because they are tumor specific and have been shown to elicit cytotoxic T cell responses. Robust phosphopeptide enrichments that are suitable for low input amounts must be developed to characterize HLA-associated phosphopeptides from clinical samples that are limited by material availability. We present two complementary mass spectrometry–compatible, iron(III)-immobilized metal affinity chromatography (IMAC) methods that use either nitrilotriacetic acid (NTA) or iminodiacetic acid (IDA) in-house-fabricated columns. We developed these protocols to enrich for subfemtomole-level phosphopeptides from cell line and human tissue samples containing picograms of starting material, which is an order of magnitude less material than what is commonly used. In addition, we added a peptide esterification step to increase phosphopeptide specificity from these low-input samples. To date, hundreds of phosphopeptides displayed on melanoma, ovarian cancer, leukemia and colorectal cancer have been identified using these highly selective phosphopeptide enrichment protocols in combination with a program called ‘CAD Neutral Loss Finder’ that identifies all spectra containing the characteristic neutral loss of phosphoric acid from phosphorylated serine and threonine residues. This methodology enables the identification of HLA-associated phosphopeptides presented by human tissue samples containing as little as nanograms of peptide material in 2 d. PMID:26247297

Abnormal metabolism of glycogen phosphate as a cause for Lafora disease.

PubMed

Tagliabracci, Vincent S; Girard, Jean Marie; Segvich, Dyann; Meyer, Catalina; Turnbull, Julie; Zhao, Xiaochu; Minassian, Berge A; Depaoli-Roach, Anna A; Roach, Peter J

2008-12-05

Lafora disease is a progressive myoclonus epilepsy with onset in the teenage years followed by neurodegeneration and death within 10 years. A characteristic is the widespread formation of poorly branched, insoluble glycogen-like polymers (polyglucosan) known as Lafora bodies, which accumulate in neurons, muscle, liver, and other tissues. Approximately half of the cases of Lafora disease result from mutations in the EPM2A gene, which encodes laforin, a member of the dual specificity protein phosphatase family that is able to release the small amount of covalent phosphate normally present in glycogen. In studies of Epm2a(-/-) mice that lack laforin, we observed a progressive change in the properties and structure of glycogen that paralleled the formation of Lafora bodies. At three months, glycogen metabolism remained essentially normal, even though the phosphorylation of glycogen has increased 4-fold and causes altered physical properties of the polysaccharide. By 9 months, the glycogen has overaccumulated by 3-fold, has become somewhat more phosphorylated, but, more notably, is now poorly branched, is insoluble in water, and has acquired an abnormal morphology visible by electron microscopy. These glycogen molecules have a tendency to aggregate and can be recovered in the pellet after low speed centrifugation of tissue extracts. The aggregation requires the phosphorylation of glycogen. The aggregrated glycogen sequesters glycogen synthase but not other glycogen metabolizing enzymes. We propose that laforin functions to suppress excessive glycogen phosphorylation and is an essential component of the metabolism of normally structured glycogen.

Mutations of cellulose synthase (CESA1) phosphorylation sites modulate anisotropic cell expansion and bidirectional mobility of cellulose synthase.

PubMed

Chen, Shaolin; Ehrhardt, David W; Somerville, Chris R

2010-10-05

The CESA1 component of cellulose synthase is phosphorylated at sites clustered in two hypervariable regions of the protein. Mutations of the phosphorylated residues to Ala (A) or Glu (E) alter anisotropic cell expansion and cellulose synthesis in rapidly expanding roots and hypocotyls. Expression of T166E, S686E, or S688E mutants of CESA1 fully rescued the temperature sensitive cesA1-1 allele (rsw1) at a restrictive temperature whereas mutations to A at these positions caused defects in anisotropic cell expansion. However, mutations to E at residues surrounding T166 (i.e., S162, T165, and S167) caused opposite effects. Live-cell imaging of fluorescently labeled CESA showed close correlations between tissue or cell morphology and patterns of bidirectional motility of CESA complexes in the plasma membrane. In the WT, CESA complexes moved at similar velocities in both directions along microtubule tracks. By contrast, the rate of movement of CESA particles was directionally asymmetric in mutant lines that exhibited abnormal tissue or cell expansion, and the asymmetry was removed upon depolymerizing microtubules with oryzalin. This suggests that phosphorylation of CESA differentially affects a polar interaction with microtubules that may regulate the length or quantity of a subset of cellulose microfibrils and that this, in turn, alters microfibril structure in the primary cell wall resulting in or contributing to the observed defect in anisotropic cell expansion.

Transforming properties of the Huntingtin interacting protein 1/ platelet-derived growth factor beta receptor fusion protein.

PubMed

Ross, T S; Gilliland, D G

1999-08-06

We have previously reported that the Huntingtin interacting protein 1 (HIP1) gene is fused to the platelet-derived growth factor beta receptor (PDGFbetaR) gene in a patient with chronic myelomonocytic leukemia. We now show that HIP1/PDGFbetaR oligomerizes, is constitutively tyrosine-phosphorylated, and transforms the murine hematopoietic cell line, Ba/F3, to interleukin-3-independent growth. A kinase-inactive mutant is neither tyrosine-phosphorylated nor able to transform Ba/F3 cells. Oligomerization and kinase activation required the 55-amino acid carboxyl-terminal TALIN homology region but not the leucine zipper domain. Tyrosine phosphorylation of a 130-kDa protein and STAT5 correlates with transformation in cells expressing HIP1/PDGFbetaR and related mutants. A deletion mutant fusion protein that contains only the TALIN homology region of HIP1 fused to PDGFbetaR is incapable of transforming Ba/F3 cells and does not tyrosine-phosphorylate p130 or STAT5, although it is itself constitutively tyrosine-phosphorylated. We have also analyzed cells expressing Tyr --> Phe mutants of HIP1/PDGFbetaR in the known PDGFbetaR SH2 docking sites and report that none of these sites are necessary for STAT5 activation, p130 phosphorylation, or Ba/F3 transformation. The correlation of factor-independent growth of hematopoietic cells with p130 and STAT5 phosphorylation/activation in both the HIP1/PDGFbetaR Tyr --> Phe and deletion mutational variants suggests that both STAT5 and p130 are important for transformation mediated by HIP1/PDGFbetaR.

ERK-dependent phosphorylation of the transcription initiation factor TIF-IA is required for RNA polymerase I transcription and cell growth.

PubMed

Zhao, Jian; Yuan, Xuejun; Frödin, Morten; Grummt, Ingrid

2003-02-01

Phosphorylation of transcription factors by mitogen-activated protein kinase (MAPK) cascades links cell signaling with the control of gene expression. Here we show that growth factors induce rRNA synthesis by activating MAPK-dependent signaling cascades that target the RNA polymerase I-specific transcription initiation factor TIF-IA. Activation of TIF-IA and ribosomal gene transcription is sensitive to PD98059, indicating that TIF-IA is targeted by MAPK in vivo. Phosphopeptide mapping and mutational analysis reveals two serine residues (S633 and S649) that are phosphorylated by ERK and RSK kinases. Replacement of S649 by alanine inactivates TIF-IA, inhibits pre-rRNA synthesis, and retards cell growth. The results provide a link between growth factor signaling, ribosome production, and cell growth, and may have a major impact on the mechanism of cell transformation.

Pathological α-synuclein in gastrointestinal tissues from prodromal Parkinson disease patients.

PubMed

Stokholm, Morten Gersel; Danielsen, Erik Hvid; Hamilton-Dutoit, Stephen Jacques; Borghammer, Per

2016-06-01

It has been hypothesized that Lewy pathology initiates in the enteric nervous system years prior to debut of clinical motor symptoms in Parkinson disease patients. This study investigates whether Lewy pathology is present in various gastrointestinal tract tissues from Parkinson disease patients in the prodromal phase. We used the Danish National Pathology Registry to identify archived paraffin-embedded tissue blocks from 57 Parkinson disease patients (98 blocks) and 90 control subjects (98 blocks). We employed 2 different immunohistochemistry techniques visualizing aggregated α-synuclein and phosphorylated α-synuclein. Thirty-nine Parkinson disease patients contributed tissues obtained in the prodromal disease phase, whereas 18 Parkinson disease patients contributed tissues obtained solely after Parkinson diagnosis. Prodromal tissues were obtained on average 7.0 years prior to diagnosis (range = 20 years to 4 months), and postdiagnosis tissue on average 2.8 years after diagnosis (range = 2 days to 18 years). Phosphorylated α-synuclein positivity was seen in 22 of 39 (56%) prodromal Parkinson disease subjects and 30 of 67 (45%) prodromal tissue blocks. These fractions were significantly higher compared to control subjects (p = 0.0001 and p = 0.0032, respectively). In contrast, no significant difference was seen in the positivity rate between prodromal Parkinson disease patients and controls when using the aggregated α-synuclein immunohistochemistry technique. We detected Lewy pathology in the gastrointestinal tract of patients up to 20 years prior to their Parkinson disease diagnosis. These findings are in accordance with a hypothesized prodromal disease phase spanning 10 to 20 years. Ann Neurol 2016;79:940-949. © 2016 American Neurological Association.

CYCLIC AMP-DEPENDENT PROTEIN KINASE INDUCTION BY POLYCHLORINATED BIPHENYLS (PCBS) STIMULATES CREB PHOSPHORYLATION VIA A CALCIUM-DEPENDENT, PKC-INDEPENDENT PATHWAY IN CORTICAL NEURONS.

EPA Science Inventory

We have previously demonstrated that the PCB mixture, Aroclor 1254 (A1254), increases the phosphorylated form of CREB (pCREB), the cAMP-responsive element binding protein. This transcription factor is important in nervous system development and plasticity. Phosphorylation
of C...

Quantitative Analysis of Tissue Samples by Combining iTRAQ Isobaric Labeling with Selected/Multiple Reaction Monitoring (SRM/MRM).

PubMed

Narumi, Ryohei; Tomonaga, Takeshi

2016-01-01

Mass spectrometry-based phosphoproteomics is an indispensible technique used in the discovery and quantification of phosphorylation events on proteins in biological samples. The application of this technique to tissue samples is especially useful for the discovery of biomarkers as well as biological studies. We herein describe the application of a large-scale phosphoproteome analysis and SRM/MRM-based quantitation to develop a strategy for the systematic discovery and validation of biomarkers using tissue samples.

Lysophosphatidic acid stimulates epidermal growth factor-family ectodomain shedding and paracrine signaling from human lung fibroblasts.

PubMed

Shiomi, Tetsuya; Boudreault, Francis; Padem, Nurcicek; Higashiyama, Shigeki; Drazen, Jeffrey M; Tschumperlin, Daniel J

2011-01-01

Lysophospatidic acid (LPA) is a bioactive lipid mediator implicated in tissue repair and wound healing. It mediates diverse functional effects in fibroblasts, including proliferation, migration and contraction, but less is known about its ability to evoke paracrine signaling to other cell types involved in wound healing. We hypothesized that human pulmonary fibroblasts stimulated by LPA would exhibit ectodomain shedding of epidermal growth factor receptor (EGFR) ligands that signal to lung epithelial cells. To test this hypothesis, we used alkaline phosphatase-tagged EGFR ligand plasmids transfected into lung fibroblasts, and enzyme-linked immunosorbent assays to detect shedding of native ligands. LPA induced shedding of alkaline phosphatase-tagged heparin-binding epidermal growth factor (HB-EGF), amphiregulin, and transforming growth factor-a; non-transfected fibroblasts shed amphiregulin and HBEGF under baseline conditions, and increased shedding of HB-EGF in response to LPA. Treatment of fibroblasts with LPA resulted in elevated phosphorylation of extracellular signal-regulated kinase 1/2, enhanced expression of mRNA for c-fos, HB-EGF and amphiregulin, and enhanced proliferation at 96 hours. However, none of these fibroblast responses to LPA required ectodomain shedding or EGFR activity. To test the ability of LPA to stimulate paracrine signaling from fibroblasts, we transferred conditioned medium from LPA-stimulated cells, and found enhanced EGFR and extracellular signal-regulated kinase 1/2 phosphorylation in reporter A549 cells in excess of what could be accounted for by transferred LPA alone. These data show that LPA mediates EGF-family ectodomain shedding, resulting in enhanced paracrine signaling from lung fibroblasts to epithelial cells. © 2011 by the Wound Healing Society.

Reciprocal regulation of YAP/TAZ by the Hippo pathway and the Small GTPase pathway.

PubMed

Jang, Ju-Won; Kim, Min-Kyu; Bae, Suk-Chul

2018-04-20

Yes-associated protein 1 (YAP) and transcriptional co-activator with PDZ-binding motif (TAZ) (YAP/TAZ) are transcriptional coactivators that regulate genes involved in proliferation and transformation by interacting with DNA-binding transcription factors. Remarkably, YAP/TAZ are essential for cancer initiation or growth of most solid tumors. Their activation induces cancer stem cell attributes, proliferation, and metastasis. The oncogenic activity of YAP/TAZ is inhibited by the Hippo cascade, an evolutionarily conserved pathway that is governed by two kinases, mammalian Ste20-like kinases 1/2 (MST1/2) and Large tumor suppressor kinase 1/2 (LATS1/2), corresponding to Drosophila's Hippo (Hpo) and Warts (Wts), respectively. One of the most influential aspects of YAP/TAZ biology is that these factors are transducers of cell structural features, including polarity, shape, and cytoskeletal organization. In turn, these features are intimately related to the cell's ability to attach to other cells and to the surrounding extracellular matrix (ECM), and are also influenced by the cell's microenvironment. Thus, YAP/TAZ respond to changes that occur at the level of whole tissues. Notably, small GTPases act as master organizers of the actin cytoskeleton. Recent studies provided convincing genetic evidence that small GTPase signaling pathways activate YAP/TAZ, while the Hippo pathway inhibits them. Biochemical studies showed that small GTPases facilitate the YAP-Tea domain transcription factor (TEAD) interaction by inhibiting YAP phosphorylation in response to serum stimulation, while the Hippo pathway facilitates the YAP-RUNX3 interaction by increasing YAP phosphorylation. Therefore, small GTPase pathways activate YAP/TAZ by switching its DNA-binding transcription factors. In this review, we summarize the relationship between the Hippo pathway and small GTPase pathways in the regulation of YAP/TAZ.

Inhibition of TGF-β Signaling in SHED Enhances Endothelial Differentiation.

PubMed

Xu, J G; Gong, T; Wang, Y Y; Zou, T; Heng, B C; Yang, Y Q; Zhang, C F

2018-02-01

Low efficiency of deriving endothelial cells (ECs) from adult stem cells hampers their utilization in tissue engineering studies. The purpose of this study was to investigate whether suppression of transforming growth factor beta (TGF-β) signaling could enhance the differentiation efficiency of dental pulp-derived stem cells into ECs. We initially used vascular endothelial growth factor A (VEGF-A) to stimulate 2 dental pulp-derived stem cells (dental pulp stem cells and stem cells from human exfoliated deciduous teeth [SHED]) and compared their differentiation capacity into ECs. We further evaluated whether the vascular endothelial growth factor receptor I (VEGF-RI)-specific ligand placental growth factor-1 (PlGF-1) could mediate endothelial differentiation. Finally, we investigated whether the TGF-β signaling inhibitor SB-431542 could enhance the inductive effect of VEGF-A on endothelial differentiation, as well as the underlying mechanisms involved. ECs differentiated from dental pulp-derived stem cells exhibited the typical phenotypes of primary ECs, with SHED possessing a higher endothelial differentiation potential than dental pulp stem cells. VEGFR1-specific ligand-PLGF exerted a negligible effect on SHED-ECs differentiation. Compared with VEGF-A alone, the combination of VEGF-A and SB-431542 significantly enhanced the endothelial differentiation of SHED. The presence of SB-431542 inhibited the phosphorylation of Suppressor of Mothers Against Decapentaplegic 2/3 (SMAD2/3), allowing for VEGF-A-dependent phosphorylation and upregulation of VEGFR2. Our results indicate that the combination of VEGF-A and SB-431542 could enhance the differentiation of dental pulp-derived stem cells into endothelial cells, and this process is mediated through enhancement of VEGF-A-VEGFR2 signaling and concomitant inhibition of TGF-β-SMAD2/3 signaling.

The MAP kinase pathway is involved in odontoblast stimulation via p38 phosphorylation.

PubMed

Simon, Stephane; Smith, Anthony J; Berdal, Ariane; Lumley, Philip J; Cooper, Paul R

2010-02-01

We have previously shown that the p38 gene is highly expressed in odontoblasts during active primary dentinogenesis, but is drastically down-regulated as cells become quiescent in secondary dentinogenesis. Based on these observations, we hypothesized that p38 expression might be upregulated, and the protein activated by phosphorylation, when odontoblasts are stimulated such as during tertiary reactionary dentinogenesis. We stimulated immortalized, odontoblast-like MDPC-23 cells, alone or in combination, with heat-inactivated Streptococcus mutans, EDTA-extracted dentine matrix proteins (DMPs), or growth factors, including transforming growth factor (TGF)-beta1, tumor necrosis factor-alpha (TNF-alpha), and adrenomedullin (ADM). We used ELISA to measure the resulting phosphorylation of the p38 protein, as well as its degree of nuclear translocation. Our results suggest that the p38-MAPKinase pathway is activated during odontoblast stimulation in tertiary dentinogenesis by both p38 phosphorylation and enhanced nuclear translocation. Data indicate that odontoblast behaviour therefore potentially recapitulates that during active primary dentinogenesis. Copyright 2010 American Association of Endodontists. All rights reserved.

Epithelial-mesenchymal transition in keloid tissues and TGF-β1-induced hair follicle outer root sheath keratinocytes.

PubMed

Yan, Li; Cao, Rui; Wang, Lianzhao; Liu, Yuanbo; Pan, Bo; Yin, Yanhua; Lv, Xiaoyan; Zhuang, Qiang; Sun, Xuejian; Xiao, Ran

2015-01-01

Keloid is a skin fibrotic disease with the characteristics of recurrence and invasion, its pathogenesis still remains unrevealed. The epithelial-mesenchymal transition (EMT) is critical for wound healing, fibrosis, recurrence, and invasion of cancer. We sought to investigate the EMT in keloid and the mechanism through which the EMT regulates keloid formation. In keloid tissues, the expressions of EMT-associated markers and transforming growth factor (TGF)-β1/Smad3 signaling were examined by immunohistochemistry. In the keloid epidermis and dermal tissue, the expressions of genes related to the regulation of skin homeostasis, fibroblast growth factor receptor 2 (FGFR2) and p63, were analyzed using quantitative real-time polymerase chain reaction. The results showed that accompanying the loss of the epithelial marker E-cadherin and the gain of the mesenchymal markers fibroblast-specific protein 1 (FSP1) and vimentin in epithelial cells from epidermis and skin appendages, and in endothelial cells from dermal microvessels, enhanced TGF-β1 expression and Smad3 phosphorylation were noted in keloid tissues. Moreover, alternative splicing of the FGFR2 gene switched the predominantly expressed isoform from FGFR2-IIIb to -IIIc, concomitant with the decreased expression of ΔNp63 and TAp63, which changes might partially account for abnormal epidermis and appendages in keloids. In addition, we found that TGF-β1-induced hair follicle outer root sheath keratinocytes (ORSKs) and normal skin epithelial cells underwent EMT in vitro with ORSKs exhibiting more obvious EMT changes and more similar expression profiles for EMT-associated and skin homeostasis-related genes as in keloid tissues, suggesting that ORSKs might play crucial roles in the EMT in keloids. Our study provided insights into the molecular mechanisms mediating the EMT pathogenesis of keloids. © 2015 by the Wound Healing Society.

Inflammation, Oxidative Stress, and Obesity

PubMed Central

Fernández-Sánchez, Alba; Madrigal-Santillán, Eduardo; Bautista, Mirandeli; Esquivel-Soto, Jaime; Morales-González, Ángel; Esquivel-Chirino, Cesar; Durante-Montiel, Irene; Sánchez-Rivera, Graciela; Valadez-Vega, Carmen; Morales-González, José A.

2011-01-01

Obesity is a chronic disease of multifactorial origin and can be defined as an increase in the accumulation of body fat. Adipose tissue is not only a triglyceride storage organ, but studies have shown the role of white adipose tissue as a producer of certain bioactive substances called adipokines. Among adipokines, we find some inflammatory functions, such as Interleukin-6 (IL-6); other adipokines entail the functions of regulating food intake, therefore exerting a direct effect on weight control. This is the case of leptin, which acts on the limbic system by stimulating dopamine uptake, creating a feeling of fullness. However, these adipokines induce the production of reactive oxygen species (ROS), generating a process known as oxidative stress (OS). Because adipose tissue is the organ that secretes adipokines and these in turn generate ROS, adipose tissue is considered an independent factor for the generation of systemic OS. There are several mechanisms by which obesity produces OS. The first of these is the mitochondrial and peroxisomal oxidation of fatty acids, which can produce ROS in oxidation reactions, while another mechanism is over-consumption of oxygen, which generates free radicals in the mitochondrial respiratory chain that is found coupled with oxidative phosphorylation in mitochondria. Lipid-rich diets are also capable of generating ROS because they can alter oxygen metabolism. Upon the increase of adipose tissue, the activity of antioxidant enzymes such as superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx), was found to be significantly diminished. Finally, high ROS production and the decrease in antioxidant capacity leads to various abnormalities, among which we find endothelial dysfunction, which is characterized by a reduction in the bioavailability of vasodilators, particularly nitric oxide (NO), and an increase in endothelium-derived contractile factors, favoring atherosclerotic disease. PMID:21686173

An animal model to study human muscular diseases involving mitochondrial oxidative phosphorylation.

PubMed

Lemieux, Hélène; Warren, Blair E

2012-08-01

Mitochondria are producing most of the energy needed for many cellular functions by a process named oxidative phosphorylation (OXPHOS). It is now well recognized that mitochondrial dysfunctions are involved in several pathologies or degenerative processes, including cardiovascular diseases, diabetes, and aging. Animal models are currently used to try to understand the role of mitochondria in human diseases but a major problem is that mitochondria from different species and tissues are variable in terms of regulation. Analysis of mitochondrial function in three species of planarian flatworms (Tricladia, Platyhelminthes) shows that they share a very rare characteristic with human mitochondria: a strong control of oxidative phosphorylation by the phosphorylation system. The ratio of coupled OXPHOS over maximal electron transport capacity after uncoupling (electron transport system; ETS) well below 1.0 indicates that the phosphorylation system is limiting the rate of OXPHOS. The OXPHOS/ETS ratios are 0.62 ± 0.06 in Dugesia tigrina, 0.63 ± 0.05 in D. dorotocephala and 0.62 ± 0.05 in Procotyla fluviatilis, comparable to the value measured in human muscles. To our knowledge, no other animal model displays this peculiarity. This new model offers a venue in which to test the phosphorylation system as a potential therapeutic control point within humans.

CASEIN KINASE-MEDIATED PHOSPHORYLATION OF SERINE 839 IS NECESSARY FOR BASOLATERAL LOCALIZATION OF THE Ca2+-ACTIVATED NON-SELECTIVE CATION CHANNEL TRPM4

PubMed Central

Cerda, Oscar; Cáceres, Mónica; Park, Kang-Sik; Leiva-Salcedo, Elías; Romero, Aníbal; Varela, Diego

2014-01-01

TRPM4 is a Ca2+-activated non-selective cation channel expressed in a wide range of human tissues. TRPM4 participates in a variety of physiological processes such as T cell activation, myogenic vasoconstriction and allergic reactions. TRPM4 Ca2+ sensitivity is enhanced by calmodulin (CaM) and phosphathydilinositol 4, 5-biphosphate (PI(4,5)P2) binding, as well as, under certain conditions, PKC activation. However, information as to the mechanisms of modulation of this channel remain unknown, including direct identification of phosphorylation sites on TRPM4 and their role in channel features. Here, we use mass-spectrometric-based proteomic approaches (immunoprecipitation and tandem mass spectrometry), to unambiguously identify S839 as a phosphorylation site present on human TRPM4 expressed in a human cell line. Site-directed mutagenesis employing a serine to alanine mutation to eliminate phosphorylation, and a phospho-mimetic aspartate mutation, as well as biochemical and immunocytochemical experiments, revealed a role for S839 phosphorylation in the basolateral expression of TRPM4 channels in epithelial cells. Moreover, we demonstrated that casein kinase 1 (CK1) phosphorylates S839 and is responsible for the basolateral localization of TRPM4. PMID:25231975

Casein kinase-mediated phosphorylation of serine 839 is necessary for basolateral localization of the Ca²⁺-activated non-selective cation channel TRPM4.

PubMed

Cerda, Oscar; Cáceres, Mónica; Park, Kang-Sik; Leiva-Salcedo, Elías; Romero, Aníbal; Varela, Diego; Trimmer, James S; Stutzin, Andrés

2015-08-01

Transient receptor potential melastatin-like 4 (TRPM4) is a Ca(2+)-activated non-selective cation channel expressed in a wide range of human tissues. TRPM4 participates in a variety of physiological processes such as T cell activation, myogenic vasoconstriction, and allergic reactions. TRPM4 Ca(2+) sensitivity is enhanced by calmodulin (CaM) and phosphathydilinositol 4, 5-bisphosphate (PI(4,5)P2) binding, as well as, under certain conditions, PKC activation. However, information as to the mechanisms of modulation of this channel remains unknown, including direct identification of phosphorylation sites on TRPM4 and their role in channel features. Here, we use mass-spectrometric-based proteomic approaches (immunoprecipitation and tandem mass spectrometry) to unambiguously identify S839 as a phosphorylation site present on human TRPM4 expressed in a human cell line. Site-directed mutagenesis employing a serine to alanine mutation to eliminate phosphorylation, and a phospho-mimetic aspartate mutation, as well as biochemical and immunocytochemical experiments, revealed a role for S839 phosphorylation in the basolateral expression of TRPM4 channels in epithelial cells. Moreover, we demonstrated that casein kinase 1 (CK1) phosphorylates S839 and is responsible for the basolateral localization of TRPM4.

Effects of PKA phosphorylation on the conformation of the Na,K-ATPase regulatory protein FXYD1

PubMed Central

Teriete, Peter; Thai, Khang; Choi, Jungyuen; Marassi, Francesca M.

2009-01-01

FXYD1 (phospholemman) is a member of an evolutionarily conserved family of membrane proteins that regulate the function of the Na,K-ATPase enzyme complex in specific tissues and specific physiological states. In heart and skeletal muscle sarcolemma, FXYD1 is also the principal substrate of hormone-regulated phosphorylation by c-AMP dependent protein kinase A and by protein kinase C, which phosphorylate the protein at conserved Ser residues in its cytoplasmic domain, altering its Na,K-ATPase regulatory activity. FXYD1 adopts an L-shaped α-helical structure with the transmembrane helix loosely connected to a cytoplasmic amphipathic helix that rests on the membrane surface. In this paper we describe NMR experiments showing that neither PKA phosphorylation at Ser68 nor the physiologically relevant phosphorylation mimicking mutation Ser68Asp induces major changes in the protein conformation. The results, viewed in light of a model of FXYD1 associated with the Na,K-ATPase α and β subunits, indicate that the effects of phosphorylation on the Na,K-ATPase regulatory activity of FXYD1 could be due primarily to changes in electrostatic potential near the membrane surface and near the Na+/K+ ion binding site of the Na,K-ATPase α subunit. PMID:19761758

Inhibition by curcumin of multiple sites of the transforming growth factor-beta1 signalling pathway ameliorates the progression of liver fibrosis induced by carbon tetrachloride in rats

PubMed Central

2012-01-01

Background At present there is no effective and accepted therapy for hepatic fibrosis. Transforming growth factor (TGF)-β1 signaling pathway contributes greatly to hepatic fibrosis. Reducing TGF-β synthesis or inhibiting components of its complex signaling pathway represent important therapeutic targets. The aim of the study was to investigate the effect of curcumin on liver fibrosis and whether curcumin attenuates the TGF-β1 signaling pathway. Methods Sprague–Dawley rat was induced liver fibrosis by carbon tetrachloride (CCl4) for six weeks together with or without curcumin, and hepatic histopathology and collagen content were employed to quantify liver necro-inflammation and fibrosis. Moreover, the mRNA and protein expression levels of TGF-β1, Smad2, phosphorylated Smad2, Smad3, Smad7 and connective tissue growth factor (CTGF) were determined by quantitative real time-PCR, Western blot, or immunohistochemistry. Results Rats treated with curcumin improved liver necro-inflammation, and reduced liver fibrosis in association with decreased α-smooth muscle actin expression, and decreased collagen deposition. Furthermore, curcumin significantly attenuated expressions of TGFβ1, Smad2, phosphorylated Smad2, Smad3, and CTGF and induced expression of the Smad7. Conclusions Curcumin significantly attenuated the severity of CCl4-induced liver inflammation and fibrosis through inhibition of TGF-β1/Smad signalling pathway and CTGF expression. These data suggest that curcumin might be an effective antifibrotic drug in the prevention of liver disease progression. PMID:22978413

Identification of bone morphogenetic protein 9 (BMP9) as a novel profibrotic factor in vitro.

PubMed

Muñoz-Félix, José M; Cuesta, Cristina; Perretta-Tejedor, Nuria; Subileau, Mariela; López-Hernández, Francisco J; López-Novoa, José M; Martínez-Salgado, Carlos

2016-09-01

Upregulated synthesis of extracellular matrix (ECM) proteins by myofibroblasts is a common phenomenon in the development of fibrosis. Although the role of TGF-β in fibrosis development has been extensively studied, the involvement of other members of this superfamily of cytokines, the bone morphogenetic proteins (BMPs) in organ fibrosis has given contradictory results. BMP9 is the main ligand for activin receptor-like kinase-1 (ALK1) TGF-β1 type I receptor and its effect on fibrosis development is unknown. Our purpose was to study the effect of BMP9 in ECM protein synthesis in fibroblasts, as well as the involved receptors and signaling pathways. In cultured mice fibroblasts, BMP9 induces an increase in collagen, fibronectin and connective tissue growth factor expression, associated with Smad1/5/8, Smad2/3 and Erk1/2 activation. ALK5 inhibition with SB431542 or ALK1/2/3/6 with dorsomorphin-1, inhibition of Smad3 activation with SIS3, and inhibition of the MAPK/Erk1/2 with U0126, demonstrates the involvement of these pathways in BMP9-induced ECM synthesis in MEFs. Whereas BMP9 induced Smad1/5/8 phosphorylation through ALK1, it also induces Smad2/3 phosphorylation through ALK5 but only in the presence of ALK1. Summarizing, this is the first study that accurately identifies BMP9 as a profibrotic factor in fibroblasts that promotes ECM protein expression through ALK1 and ALK5 receptors. Copyright © 2016 Elsevier Inc. All rights reserved.

Double-stranded RNA-activated protein kinase is a key modulator of insulin sensitivity in physiological conditions and in obesity in mice.

PubMed

Carvalho-Filho, M A; Carvalho, B M; Oliveira, A G; Guadagnini, D; Ueno, M; Dias, M M; Tsukumo, D M; Hirabara, S M; Reis, L F; Curi, R; Carvalheira, J B C; Saad, Mario J A

2012-11-01

The molecular integration of nutrient- and pathogen-sensing pathways has become of great interest in understanding the mechanisms of insulin resistance in obesity. The double-stranded RNA-dependent protein kinase (PKR) is one candidate molecule that may provide cross talk between inflammatory and metabolic signaling. The present study was performed to determine, first, the role of PKR in modulating insulin action and glucose metabolism in physiological situations, and second, the role of PKR in insulin resistance in obese mice. We used Pkr(-/-) and Pkr(+/+) mice to investigate the role of PKR in modulating insulin sensitivity, glucose metabolism, and insulin signaling in liver, muscle, and adipose tissue in response to a high-fat diet. Our data show that in lean Pkr(-/-) mice, there is an improvement in insulin sensitivity, and in glucose tolerance, and a reduction in fasting blood glucose, probably related to a decrease in protein phosphatase 2A activity and a parallel increase in insulin-induced thymoma viral oncogene-1 (Akt) phosphorylation. PKR is activated in tissues of obese mice and can induce insulin resistance by directly binding to and inducing insulin receptor substrate (IRS)-1 serine307 phosphorylation or indirectly through modulation of c-Jun N-terminal kinase and inhibitor of κB kinase β. Pkr(-/-) mice were protected from high-fat diet-induced insulin resistance and glucose intolerance and showed improved insulin signaling associated with a reduction in c-Jun N-terminal kinase and inhibitor of κB kinase β phosphorylation in insulin-sensitive tissues. PKR may have a role in insulin sensitivity under normal physiological conditions, probably by modulating protein phosphatase 2A activity and serine-threonine kinase phosphorylation, and certainly, this kinase may represent a central mechanism for the integration of pathogen response and innate immunity with insulin action and metabolic pathways that are critical in obesity.

Antitumor efficacy profile of PKI-402, a dual phosphatidylinositol 3-kinase/mammalian target of rapamycin inhibitor.

PubMed

Mallon, Robert; Hollander, Irwin; Feldberg, Larry; Lucas, Judy; Soloveva, Veronica; Venkatesan, Aranapakam; Dehnhardt, Christoph; Delos Santos, Efren; Chen, Zecheng; Dos Santos, Osvaldo; Ayral-Kaloustian, Semiramis; Gibbons, Jay

2010-04-01

PKI-402 is a selective, reversible, ATP-competitive, equipotent inhibitor of class I phosphatidylinositol 3-kinases (PI3K), including PI3K-alpha mutants, and mammalian target of rapamycin (mTOR; IC(50) versus PI3K-alpha = 2 nmol/L). PKI-402 inhibited growth of human tumor cell lines derived from breast, brain (glioma), pancreas, and non-small cell lung cancer tissue and suppressed phosphorylation of PI3K and mTOR effector proteins (e.g., Akt at T308) at concentrations that matched those that inhibited cell growth. In MDA-MB-361 [breast: Her2(+) and PIK3CA mutant (E545K)], 30 nmol/L PKI-402 induced cleaved poly(ADP-ribose) polymerase (PARP), a marker for apoptosis. In vivo, PKI-402 inhibited tumor growth in MDA-MB-361, glioma (U87MG), and lung (A549) xenograft models. In MDA-MB-361, PKI-402 at 100 mg/kg (daily for 5 days, one round) reduced initial tumor volume of 260 mm(3) to 129 mm(3) and prevented tumor regrowth for 70 days. In MDA-MB-361 tumors, PKI-402 (100 mg/kg, single dose) suppressed Akt phosphorylation (at T308) and induced cleaved PARP. Suppression of phosphorylated Akt (p-Akt) was complete at 8 hours and still evident at 24 hours. Cleaved PARP was evident at 8 and 24 hours. In normal tissue (heart and lung), PKI-402 (100 mg/kg) had minimal effect on p-Akt, with no detectable cleaved PARP. Preferential accumulation of PKI-402 in tumor tissue was observed. Complete, sustained suppression of Akt phosphorylation may cause tumor regression in MDA-MB-361 and other xenograft models. We are testing whether dual PI3K/mTOR inhibitors can durably suppress p-Akt, induce cleaved PARP, and cause tumor regression in a diverse set of human tumor xenograft models. Mol Cancer Ther; 9(4); 976-84. (c)2010 AACR.

Decoy receptor 3 suppresses FasL-induced apoptosis via ERK1/2 activation in pancreatic cancer cells.

PubMed

Zhang, Yi; Li, Dechun; Zhao, Xin; Song, Shiduo; Zhang, Lifeng; Zhu, Dongming; Wang, Zhenxin; Chen, Xiaochen; Zhou, Jian

2015-08-07

Resistance to Fas Ligand (FasL) mediated apoptosis plays an important role in tumorigenesis. Decoy receptor 3 (DcR3) is reported to interact with FasL and is overexpressed in some malignant tumors. We sought to investigate the role of DcR3 in resistance to FasL in pancreatic cancer. We compared expression of apoptosis related genes between FasL-resistant SW1990 and FasL-sensitive Patu8988 pancreatic cell lines by microarray analysis. We explored the impact of siRNA knockdown of, or exogenous supplementation with, DcR3 on FasL-induced cell growth inhibition in pancreatic cancer cell lines and expression of proteins involved in apoptotic signaling. We assessed the level of DcR3 protein and ERK1/2 phosphorylation in tumor and non-tumor tissue samples of 66 patients with pancreatic carcinoma. RNAi knockdown of DcR3 expression in SW1990 cells reduced resistance to FasL-induced apoptosis, and supplementation of Patu8988 with rDcR3 had the opposite effect. RNAi knockdown of DcR3 in SW1990 cells elevated expression of caspase 3, 8 and 9, and reduced ERK1/2 phosphorylation (P < 0.05), but did not alter phosphorylated-Akt expression. 47 tumor tissue specimens, but only 15 matched non-tumor specimens stained for DcR3 (χ(2) = 31.1447, P < 0.001). The proliferation index of DcR3 positive specimens (14.26  ±  2.67%) was significantly higher than that of DcR3 negative specimens (43.58  ±  7.88%, P < 0.01). DcR3 expression positively correlated with p-ERK1/2 expression in pancreatic cancer tissues (r = 0.607, P < 0.001). DcR3 enhances ERK1/2 phosphorylation and opposes FasL signaling in pancreatic cancer cells. Copyright © 2015 Elsevier Inc. All rights reserved.

[Molecular mechanism for ET-1-induced insulin resistance in skeletal muscle cells].

PubMed

Horinouchi, Takahiro; Mazaki, Yuichi; Terada, Koji; Miwa, Soichi

2018-01-01

Insulin resistance is a condition where the sensitivity to insulin of the tissues expressing insulin receptor (InsR) is decreased due to a functional disturbance of InsR-mediated intracellular signaling. Insulin promotes the entry of glucose into the tissues and skeletal muscle is the most important tissue responsible for the insulin's action of decreasing blood glucose levels. Endothelin-1 (ET-1), a potent vasoconstrictor and pro-inflammatory peptide, induces insulin resistance through a direct action on skeletal muscle. However, the signaling pathways of ET-1-induced insulin resistance in skeletal muscle remain unclear. Here we show molecular mechanism underlying the inhibitory effect of ET-1 on insulin-stimulated Akt phosphorylation and glucose uptake in myotubes of rat L6 skeletal muscle cell line. mRNA expression levels of differentiation marker genes, MyoD and myogenin, were increased during L6 myoblasts differentiation into myotubes. Some of myotubes possessed the ability to spontaneously contract. In myotubes, insulin promoted Akt phosphorylation at Thr 308 and Ser 473 , and [ 3 H]-labelled 2-deoxy-D-glucose ([ 3 H]2-DG) uptake. The insulin-facilitated Akt phosphorylation and [ 3 H]2-DG uptake were inhibited by ET-1. The inhibitory effect of ET-1 was counteracted by blockade of ET type A receptor (ET A R), inhibition of G q/11 protein, and siRNA knockdown of G protein-coupled receptor kinase 2 (GRK2). The exogenously overexpressed GRK2 directly bound to endogenous Akt and their association was facilitated by ET-1. In summary, activation of ET A R with ET-1 inhibits insulin-induced Akt phosphorylation and [ 3 H]2-DG uptake in a G q/11 protein- and GRK2-dependent manner in skeletal muscle. These findings indicate that ET A R and GRK2 are potential targets for insulin resistance.

MATRIX METALLOPROTEINS (MMP)-MEDIATED PHOSPHORYLATION OF THE EPIDERMAL GROWTH FACTOR RECEPTOR (EGFR) IN HUMAN AIRWAY EPITHELIAL CELLS (HAEC) EXPOSED TO ZINC (ZN)

EPA Science Inventory

Matrix Metalloproteinase (MMP)-Mediated Phosphorylation of The Epidermal Growth Factor Receptor (EGFR) in Human Airway Epithelial Cells (HAEC) Exposed to Zinc (Zn)
Weidong Wu, James M. Samet, Robert Silbajoris, Lisa A. Dailey, Lee M. Graves, and Philip A. Bromberg
Center fo...

Direct effects of hypoxia and nitric oxide on ecdysone secretion by insect prothoracic glands.

PubMed

DeLalio, Leon J; Dion, Sara M; Bootes, Abigail M; Smith, Wendy A

2015-05-01

Insect molting and metamorphosis are controlled by the molt stimulating hormone ecdysone. A recent study suggests that reduced tissue oxygenation correlates with the size-sensing mechanism responsible for triggering molting. When reared in hypoxia, larvae of Manduca sexta and Drosophila melanogaster initiate molting at lower weights than do larvae reared in normoxia. Furthermore, in Drosophila, the signaling gas nitric oxide (NO) appears to be required for normal developmental timing. As observed in Drosophila, NO signaling targets the nuclear hormone receptor beta fushi tarazu transcription factor 1 (βFTZ-F1) through activation of Drosophila hormone receptor 3 (DHR3), two key regulators of ecdysone production and metamorphic tissue progression. We set out to directly examine the effects of hypoxia and NO on ecdysone secretion using prothoracic glands from feeding fifth (last) larval stage M. sexta. Our results indicate that in vitro treatment of prothoracic glands with hypoxia (2% oxygen) or the NO donor DETA-NONOate significantly inhibit ecdysone secretion. Protein markers of glandular activity were also in keeping with an initial inhibition, measured a decrease in phosphorylated ERK (extracellular signal regulated kinase) and an increase in non-phosphorylated 4EBP (eukaryotic initiation factor 4E binding protein). Additionally, gene expression levels of Manduca hormone receptor 3 (mhr3), βftz-f1, nitric oxide synthase (nos), and the PTTH receptor torso, were quantified using real-time PCR. NO treatment increased mhr3 expression and decreased nos expression. Hypoxia increased mhr3 transcription after 2 hr, but decreased transcription after 12 hr, with no effect on nos expression. Both NO and hypoxia had small effects on βftz-f1 expression, yet strongly increased torso transcription. Our results demonstrate that, in isolated prothoracic glands, hypoxia and NO signaling directly inhibit ecdysteroid secretion, but at the same time alter aspects of prothoracic gland function that may enhance secretory response. Copyright © 2015 Elsevier Ltd. All rights reserved.

Temporal quantitation of mutant Kit tyrosine kinase signaling attenuated by a novel thiophene kinase inhibitor OSI-930.

PubMed

Petti, Filippo; Thelemann, April; Kahler, Jen; McCormack, Siobhan; Castaldo, Linda; Hunt, Tony; Nuwaysir, Lydia; Zeiske, Lynn; Haack, Herbert; Sullivan, Laura; Garton, Andrew; Haley, John D

2005-08-01

OSI-930, a potent thiophene inhibitor of the Kit, KDR, and platelet-derived growth factor receptor tyrosine kinases, was used to selectively inhibit tyrosine phosphorylation downstream of juxtamembrane mutant Kit in the mast cell leukemia line HMC-1. Inhibition of Kit kinase activity resulted in a rapid dephosphorylation of Kit and inhibition of the downstream signaling pathways. Attenuation of Ras-Raf-Erk (phospho-Erk, phospho-p38), phosphatidyl inositol-3' kinase (phospho-p85, phospho-Akt, phospho-S6), and signal transducers and activators of transcription signaling pathways (phospho-STAT3/5/6) were measured by affinity liquid chromatography tandem mass spectrometry, by immunoblot, and by tissue microarrays of fixed cell pellets. To more globally define additional components of Kit signaling temporally altered by kinase inhibition, a novel multiplex quantitative isobaric peptide labeling approach was used. This approach allowed clustering of proteins by temporal expression patterns. Kit kinase, which dephosphorylates rapidly upon kinase inhibition, was shown to regulate both Shp-1 and BDP-1 tyrosine phosphatases and the phosphatase-interacting protein PSTPIP2. Interactions with SH2 domain adapters [growth factor receptor binding protein 2 (Grb2), Cbl, Slp-76] and SH3 domain adapters (HS1, cortactin, CD2BP3) were attenuated by inhibition of Kit kinase activity. Functional crosstalk between Kit and the non-receptor tyrosine kinases Fes/Fps, Fer, Btk, and Syk was observed. Inhibition of Kit modulated phosphorylation-dependent interactions with pathways controlling focal adhesion (paxillin, leupaxin, p130CAS, FAK1, the Src family kinase Lyn, Wasp, Fhl-3, G25K, Ack-1, Nap1, SH3P12/ponsin) and septin-actin complexes (NEDD5, cdc11, actin). The combined use of isobaric protein quantitation and expression clustering, immunoblot, and tissue microarray strategies allowed temporal measurement signaling pathways modulated by mutant Kit inhibition in a model of mast cell leukemia.

Mechanical strain induces involution-associated events in mammary epithelial cells

PubMed Central

Quaglino, Ana; Salierno, Marcelo; Pellegrotti, Jesica; Rubinstein, Natalia; Kordon, Edith C

2009-01-01

Background Shortly after weaning, a complex multi-step process that leads to massive epithelial apoptosis is triggered by tissue local factors in the mouse mammary gland. Several reports have demonstrated the relevance of mechanical stress to induce adaptive responses in different cell types. Interestingly, these signaling pathways also participate in mammary gland involution. Then, it has been suggested that cell stretching caused by milk accumulation after weaning might be the first stimulus that initiates the complete remodeling of the mammary gland. However, no previous report has demonstrated the impact of mechanical stress on mammary cell physiology. To address this issue, we have designed a new practical device that allowed us to evaluate the effects of radial stretching on mammary epithelial cells in culture. Results We have designed and built a new device to analyze the biological consequences of applying mechanical stress to cells cultured on flexible silicone membranes. Subsequently, a geometrical model that predicted the percentage of radial strain applied to the elastic substrate was developed. By microscopic image analysis, the adjustment of these calculations to the actual strain exerted on the attached cells was verified. The studies described herein were all performed in the HC11 non-tumorigenic mammary epithelial cell line, which was originated from a pregnant BALB/c mouse. In these cells, as previously observed in other tissue types, mechanical stress induced ERK1/2 phosphorylation and c-Fos mRNA and protein expression. In addition, we found that mammary cell stretching triggered involution associated cellular events as Leukemia Inhibitory Factor (LIF) expression induction, STAT3 activation and AKT phosphorylation inhibition. Conclusion Here, we show for the first time, that mechanical strain is able to induce weaning-associated events in cultured mammary epithelial cells. These results were obtained using a new practical and affordable device specifically designed for such a purpose. We believe that our results indicate the relevance of mechanical stress among the early post-lactation events that lead to mammary gland involution. PMID:19615079

Gallic Acid Attenuates Postoperative Intra-Abdominal Adhesion by Inhibiting Inflammatory Reaction in a Rat Model

PubMed Central

Wei, Guangbing; Wu, Yunhua; Gao, Qi; Shen, Cong; Chen, Zilu; Wang, Kang; Yu, Junhui

2018-01-01

Background Intra-abdominal adhesion is one of the most common complications after abdominal surgery. The efficacy of current treatments for intra-abdominal adhesion is unsatisfactory. In this study, we investigated the effect of gallic acid on the prevention and treatment of intra-abdominal adhesions after abdominal surgery using an intra-abdominal adhesion rat model. Material/Methods The experimental rats were randomly divided into the sham operation group, the control group, the chitosan group, and 3 gallic acid groups of different concentrations. All rats except those in the sham operation group received cecal abrasion to induce adhesion. From the first postoperative day, the rats in the gallic acid groups were administered different concentrations of gallic acid in a 2-ml gavage daily. All rats were sacrificed on postoperative day 7, and the degree of intra-abdominal adhesion was evaluated by the naked eye. The amount of collagen deposited between the injured peritoneal tissues was assessed by Sirius red staining. Serum levels of interleukin-6 (IL-6), tumor necrosis factor (TNF-α), and transforming growth factor-β (TGF-β) were measured by ELISA. Western blot was used to detect the level of NF-κB phosphorylation in the injured peritoneal or adhesion tissues of the rats. Results Compared with the control group, the scores of intra-abdominal adhesions in the rats treated with larger doses of gallic acid were significantly decreased, and the degree of inflammation and fibrosis was also significantly decreased. Gallic acid significantly reduced IL-6, TNF-α, and TGF-β1 serum levels. NF-κB phosphorylation in the higher gallic acid groups was significantly reduced. Conclusions Gallic acid inhibits the formation of postoperative intra-abdominal adhesions in rats by inhibiting the inflammatory reaction and fibrogenesis. Gallic acid is a promising drug for preventing intra-abdominal adhesions. PMID:29429982

Effect of epidermal growth factor (EGF) on the phosphorylation of mitogen-activated protein kinase (MAPK) in the bovine oviduct in vitro: Alteration by heat stress.

PubMed

Wijayagunawardane, Missaka P B; Hambruch, Nina; Haeger, Jan-Dirk; Pfarrer, Christiane

2015-01-01

Epidermal growth factor (EGF) has been shown to be involved in control of the oviductal microenvironment. To elucidate the potential mechanisms responsible for the detrimental effect of heat stress and to identify the relation with the endocrine status, the effects of EGF on the level of phosphorylated mitogen-activated-protein kinase (MAPK) and proliferation of bovine oviductal epithelial cells (OECs) exposed to different cyclic ovarian steroidal environments (luteal phase (LP), follicular phase (FP) and postovulatory phase (PO)) and temperatures (mild heat stress (40 C) and severe heat stress (43 C)) were investigated. Western blot was performed to evaluate phosphorylated MAPK, while proliferation was analyzed by MTT assay. Stimulation of OECs with EGF alone or with EGF in the PO and FP environments significantly increased the amount of phosphorylated MAPK, with MAPK 44 phosphorylation being highest during exposure to PO conditions. These effects were not observed in the LP. Heat treatment completely blocked effects of EGF on phosphorylated MAPK. Additionally, severe heat stress led to a significantly lower basal level of phosphorylated MAPK. PD98059 (MAPK inhibitor) completely abolished EGF-stimulated MAPK phosphorylation and OECs proliferation. Overall the results indicate that EGF has the potential to increase the amount of phosphorylated MAPK in OECs and therefore could be involved in regulation of the bovine oviductal microenvironment. However, these regulatory mechanisms may be compromised in the presence of heat stress (high ambient temperature), leading to low fertility rates and impaired embryo survival.

Effect of epidermal growth factor (EGF) on the phosphorylation of mitogen-activated protein kinase (MAPK) in the bovine oviduct in vitro: Alteration by heat stress

PubMed Central

WIJAYAGUNAWARDANE, Missaka P. B.; HAMBRUCH, Nina; HAEGER, Jan-Dirk; PFARRER, Christiane

2015-01-01

Epidermal growth factor (EGF) has been shown to be involved in control of the oviductal microenvironment. To elucidate the potential mechanisms responsible for the detrimental effect of heat stress and to identify the relation with the endocrine status, the effects of EGF on the level of phosphorylated mitogen-activated-protein kinase (MAPK) and proliferation of bovine oviductal epithelial cells (OECs) exposed to different cyclic ovarian steroidal environments (luteal phase (LP), follicular phase (FP) and postovulatory phase (PO)) and temperatures (mild heat stress (40 C) and severe heat stress (43 C)) were investigated. Western blot was performed to evaluate phosphorylated MAPK, while proliferation was analyzed by MTT assay. Stimulation of OECs with EGF alone or with EGF in the PO and FP environments significantly increased the amount of phosphorylated MAPK, with MAPK 44 phosphorylation being highest during exposure to PO conditions. These effects were not observed in the LP. Heat treatment completely blocked effects of EGF on phosphorylated MAPK. Additionally, severe heat stress led to a significantly lower basal level of phosphorylated MAPK. PD98059 (MAPK inhibitor) completely abolished EGF-stimulated MAPK phosphorylation and OECs proliferation. Overall the results indicate that EGF has the potential to increase the amount of phosphorylated MAPK in OECs and therefore could be involved in regulation of the bovine oviductal microenvironment. However, these regulatory mechanisms may be compromised in the presence of heat stress (high ambient temperature), leading to low fertility rates and impaired embryo survival. PMID:26050642

[(Pro) renin receptor in the pathogenesis of proliferative diabetic retinopathy].

PubMed

Kanda, Atsuhiro

2014-11-01

The renin-angiotensin system (RAS), originally regarded as an important controller of systemic blood pressure (circulatory RAS), plays a pivotal role in pathological vascular conditions including inflammation and angiogenesis (tissue RAS). (Pro) renin receptor [(P) RR] is known to bind with prorenin causing the dual activation of tissue renin-angiotensin system (RAS) together with RAS-independent intracellular signaling pathways and contributes to the molecular pathogenesis of end-organ damage. In this review, we investigated localization and expression of (P)RR in fibrovascular tissues and vitreous fluids from patients with proliferative diabetic retinopathy and evaluated the molecular mechanisms in vitro in order to confirm the conclusions regarding (P) RR from animal studies. (P)RR immunoreactivity was detected in vascular endothelial cells, co-localized with prorenin, phosphorylated extracellular signal-regulated kinase and vascular endothelial growth factor (VEGF). Protein levels of soluble (P) RR in the vitreous fluids were higher in proliferative diabetic retinopathy (PDR) eyes than in non-diabetic control eyes, and were significantly correlated with vitreous VEGF levels and the vascular density of fibrovascular tissues. We herein report the first evidence that shows the close association of (P) RR with angiogenic activity in human PDR. The present data suggest the validity of (P) RR as a molecular target for the treatment of PDR.

Estrogen receptor β regulates endometriotic cell survival through SGK1 activation

PubMed Central

Monsivais, Diana; Dyson, Matthew T.; Yin, Ping; Navarro, Antonia; Coon, John S; Pavone, Mary Ellen; Bulun, Serdar E.

2016-01-01

OBJECTIVE To determine the expression and biological roles of SGK1 in tissues and cells from patients with endometriosis and from healthy controls. DESIGN Case-control. SETTING University research setting. PATIENTS Premenopausal women. INTERVENTIONS Endometriotic tissues (E-Osis) were obtained from women with ovarian endometriosis and normal endometrial tissues (NoEM) were obtained from women undergoing hysterectomy for benign conditions. MAIN OUTCOMES MEASURES Expression levels of serum and glucocorticoid regulated kinase (SGK1), the role of SGK1 in E-Osis pathology, and the regulation of SGK1 by ERβ. RESULTS Transcript and protein levels of SGK1 were significantly higher in endometriotic tissues and cells compared to normal endometrium. SGK1 mRNA and protein levels were stimulated by estradiol, by the ERβ-selective agonist, diarylpropionitrile, and by prostaglandin E2. SGK1 was transcriptionally regulated by ERβ based on siRNA knockdown and chromatin immunoprecipitation of ERβ followed by quantitative PCR (ChIP-qPCR). SGK1 knockdown led to increased cleavage of PARP, and SGK1 activation was correlated with the phosphorylation of FOXO3a, a pro-apoptotic factor. CONCLUSIONS ERβ leads to SGK1 overexpression in endometriosis, which contributes to the survival of endometriotic lesions through inhibition of apoptosis. PMID:26827666

Progranulin, a Major Secreted Protein of Mouse Adipose-Derived Stem Cells, Inhibits Light-Induced Retinal Degeneration

PubMed Central

Tsuruma, Kazuhiro; Yamauchi, Mika; Sugitani, Sou; Otsuka, Tomohiro; Ohno, Yuta; Nagahara, Yuki; Ikegame, Yuka; Shimazawa, Masamitsu; Yoshimura, Shinichi; Iwama, Toru

2014-01-01

Adipose tissue stromal vascular fraction contains mesenchymal stem cells, which show protective effects when administered to damaged tissues, mainly through secreted trophic factors. We examined the protective effects of adipose-derived stem cells (ASCs) and ASC-conditioned medium (ASC-CM) against retinal damage and identified the neuroprotective factors in ASC-CM. ASCs and mature adipocytes were isolated from mouse subcutaneous tissue. ASCs were injected intravitreally in a mouse model of light-induced retinal damage, and ASC injection recovered retinal function as measured by electroretinogram and inhibited outer nuclear layer, thinning, without engraftment of ASCs. ASC-CM and mature adipocyte-conditioned medium were collected after 72 hours of culture. In vitro, H2O2- and light-induced cell death was reduced in a photoreceptor cell line with ASC-CM but not with mature adipocyte-conditioned medium. In vivo, light-induced photoreceptor damage was evaluated by measurement of outer nuclear layer thickness at 5 days after light exposure and by electroretinogram recording. ASC-CM significantly inhibited photoreceptor degeneration and retinal dysfunction after light exposure. Progranulin was identified as a major secreted protein of ASCs that showed protective effects against retinal damage in vitro and in vivo. Furthermore, progranulin phosphorylated extracellular signal-regulated kinase, cAMP response element binding protein, and hepatocyte growth factor receptor, and protein kinase C signaling pathways were involved in the protective effects of progranulin. These findings suggest that ASC-CM and progranulin have neuroprotective effects in the light-induced retinal-damage model. Progranulin may be a potential target for the treatment of the degenerative diseases of the retina. PMID:24233842

Progranulin, a major secreted protein of mouse adipose-derived stem cells, inhibits light-induced retinal degeneration.

PubMed

Tsuruma, Kazuhiro; Yamauchi, Mika; Sugitani, Sou; Otsuka, Tomohiro; Ohno, Yuta; Nagahara, Yuki; Ikegame, Yuka; Shimazawa, Masamitsu; Yoshimura, Shinichi; Iwama, Toru; Hara, Hideaki

2014-01-01

Adipose tissue stromal vascular fraction contains mesenchymal stem cells, which show protective effects when administered to damaged tissues, mainly through secreted trophic factors. We examined the protective effects of adipose-derived stem cells (ASCs) and ASC-conditioned medium (ASC-CM) against retinal damage and identified the neuroprotective factors in ASC-CM. ASCs and mature adipocytes were isolated from mouse subcutaneous tissue. ASCs were injected intravitreally in a mouse model of light-induced retinal damage, and ASC injection recovered retinal function as measured by electroretinogram and inhibited outer nuclear layer, thinning, without engraftment of ASCs. ASC-CM and mature adipocyte-conditioned medium were collected after 72 hours of culture. In vitro, H2O2- and light-induced cell death was reduced in a photoreceptor cell line with ASC-CM but not with mature adipocyte-conditioned medium. In vivo, light-induced photoreceptor damage was evaluated by measurement of outer nuclear layer thickness at 5 days after light exposure and by electroretinogram recording. ASC-CM significantly inhibited photoreceptor degeneration and retinal dysfunction after light exposure. Progranulin was identified as a major secreted protein of ASCs that showed protective effects against retinal damage in vitro and in vivo. Furthermore, progranulin phosphorylated extracellular signal-regulated kinase, cAMP response element binding protein, and hepatocyte growth factor receptor, and protein kinase C signaling pathways were involved in the protective effects of progranulin. These findings suggest that ASC-CM and progranulin have neuroprotective effects in the light-induced retinal-damage model. Progranulin may be a potential target for the treatment of the degenerative diseases of the retina.

CCN2/CTGF binds to fibroblast growth factor receptor 2 and modulates its signaling.

PubMed

Aoyama, Eriko; Kubota, Satoshi; Takigawa, Masaharu

2012-12-14

CCN2 plays a critical role in the development of mesenchymal tissues such as cartilage and bone, and the binding of CCN2 to various cytokines and receptors regulates their signaling.By screening a protein array, we found that CCN2 could bind to fibroblast growth factor receptors (FGFRs) 2 and 3, with a higher affinity toward FGFR2.We ascertained that FGFR2 bound to CCN2 and that the binding of FGFR2 to FGF2 and FGF4 was enhanced by CCN2.CCN2 and FGF2 had a collaborative effect on the phosphorylation of ERK and the differentiation of osteoblastic cells.The present results indicate the biological significance of the binding of CCN2 to FGFR2 in bone metabolism. Copyright © 2012 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.

Phosphorylation of h1 Calponin by PKC epsilon may contribute to facilitate the contraction of uterine myometrium in mice during pregnancy and labor

PubMed Central

2012-01-01

Background The timely onset of powerful uterine contractions during parturition occurs through thick and thin filament interactions, similar to other smooth muscle tissues. Calponin is one of the thin filament proteins. Phosphorylation of calponin induced by PKC-epsilon can promote the contraction of vascular smooth muscle. While the mechanism by which calponin regulates the contraction of pregnant myometrium has rarely been explored. Here, we explore whether PKC-epsilon/h1 calponin pathway contribute to regulation of myometrial contractility and development of parturition. Methods We detected the expression of h1 calponin, phosphorylated h1 calponin, PKC-epsilon and phosphorylated PKC-epsilon in the different stages of mice during pregnancy and in labor by the method of western blot and recorded the contraction activity of myometrium strips at the 19th day during pregnancy with different treatments by the organ bath experiments. Results The level of the four proteins including h1 calponin, phosphorylated h1 calponin, PKC-epsilon and phosphorylated PKC-epsilon was significantly increased in pregnant mice myometrium as compared with that in nonpregnant mice. The ratios of phosphorylated h1 calponin/h1 calponin and phosphorylated PKC-epsilon/PKC-epsilon were reached the peak after the onset of labor in myometrium in the mice. After the treatment of more than 10(9-) mol/L Psi-RACK (PKC-epsilon activator), the contractility of myometrium strips from mice was reinforced and the level of phosphorylated h1 calponin increased at the same time which could be interrupted by the specific inhibitor of PKC-epsilon. Meanwhile, the change of the ratio of phosphorylated h1 calponin/h1 calponin was consistent with that of contraction force of mice myometrium strips. Conclusions These data suggest that in mice myometrium, phosphorylation of h1 calponin induced by the PKC-epsilon might facilitate the contraction of uterine in labor and regulate pregnant myometrial contractility. PMID:22551221

EGFR Ligands Drive Multipotential Stromal Cells to Produce Multiple Growth Factors and Cytokines via Early Growth Response-1

PubMed Central

Kerpedjieva, Svetoslava S.; Kim, Duk Soo; Barbeau, Dominique J.

2012-01-01

Cell therapy with adult bone marrow multipotential stromal cells/mesenchymal stem cells (MSCs) presents a promising approach to promote wound healing and tissue regeneration. The strong paracrine capability of various growth factors and cytokines is a key mechanism of MSC-mediated wound healing and tissue regeneration, and the goal of this study is to understand the underlying mechanism that supports the strong paracrine machineries in MSCs. Microarray database analyses revealed that early growth response-1 (EGR1) is highly expressed in MSCs. Our previous studies showed that epidermal growth factor (EGF) treatment induces growth factor production in MSCs in vitro. Since EGF strongly upregulates EGR1, we hypothesized that EGF receptor (EGFR)–EGR1 signaling plays a pivotal role in MSC paracrine activity. EGF treatment upregulated the gene expression of growth factors and cytokines, including EGFR ligands in a protein kinase C (PKC)- and/or mitogen-activated protein kinase–extracellular-signal-regulated kinase-dependent manner, and it was reversed by shRNA against EGR1. PKC activator phorbol 12-myristate 13-acetate enhanced EGFR tyrosyl phosphorylation and upregulated the gene expression of growth factors and cytokines in a heparin-binding EGF-like growth factor (HBEGF) inhibitor CRM197 sensitive manner, indicating an involvement of autocrined HBEGF in the downstream of PKC signaling. Moreover, stimulation with growth factors and cytokines induced the expression of EGFR ligands, presumably via EGR1 upregulation. These data indicate EGR1 as a convergence point of multiple signaling pathways, which in turn augments the production of multiple growth factors and cytokines by enhancing the autocrine signaling with EGFR ligands. PMID:22316125

EGFR ligands drive multipotential stromal cells to produce multiple growth factors and cytokines via early growth response-1.

PubMed

Kerpedjieva, Svetoslava S; Kim, Duk Soo; Barbeau, Dominique J; Tamama, Kenichi

2012-09-01

Cell therapy with adult bone marrow multipotential stromal cells/mesenchymal stem cells (MSCs) presents a promising approach to promote wound healing and tissue regeneration. The strong paracrine capability of various growth factors and cytokines is a key mechanism of MSC-mediated wound healing and tissue regeneration, and the goal of this study is to understand the underlying mechanism that supports the strong paracrine machineries in MSCs. Microarray database analyses revealed that early growth response-1 (EGR1) is highly expressed in MSCs. Our previous studies showed that epidermal growth factor (EGF) treatment induces growth factor production in MSCs in vitro. Since EGF strongly upregulates EGR1, we hypothesized that EGF receptor (EGFR)-EGR1 signaling plays a pivotal role in MSC paracrine activity. EGF treatment upregulated the gene expression of growth factors and cytokines, including EGFR ligands in a protein kinase C (PKC)- and/or mitogen-activated protein kinase-extracellular-signal-regulated kinase-dependent manner, and it was reversed by shRNA against EGR1. PKC activator phorbol 12-myristate 13-acetate enhanced EGFR tyrosyl phosphorylation and upregulated the gene expression of growth factors and cytokines in a heparin-binding EGF-like growth factor (HBEGF) inhibitor CRM197 sensitive manner, indicating an involvement of autocrined HBEGF in the downstream of PKC signaling. Moreover, stimulation with growth factors and cytokines induced the expression of EGFR ligands, presumably via EGR1 upregulation. These data indicate EGR1 as a convergence point of multiple signaling pathways, which in turn augments the production of multiple growth factors and cytokines by enhancing the autocrine signaling with EGFR ligands.

A new TAO kinase inhibitor reduces tau phosphorylation at sites associated with neurodegeneration in human tauopathies.

PubMed

Giacomini, Caterina; Koo, Chuay-Yeng; Yankova, Natalia; Tavares, Ignatius A; Wray, Selina; Noble, Wendy; Hanger, Diane P; Morris, Jonathan D H

2018-05-07

In Alzheimer's disease (AD) and related tauopathies, the microtubule-associated protein tau is highly phosphorylated and aggregates to form neurofibrillary tangles that are characteristic of these neurodegenerative diseases. Our previous work has demonstrated that the thousand-and-one amino acid kinases (TAOKs) 1 and 2 phosphorylate tau on more than 40 residues in vitro. Here we show that TAOKs are phosphorylated and active in AD brain sections displaying mild (Braak stage II), intermediate (Braak stage IV) and advanced (Braak stage VI) tau pathology and that active TAOKs co-localise with both pre-tangle and tangle structures. TAOK activity is also enriched in pathological tau containing sarkosyl-insoluble extracts prepared from AD brain. Two new phosphorylated tau residues (T123 and T427) were identified in AD brain, which appear to be targeted specifically by TAOKs. A new small molecule TAOK inhibitor (Compound 43) reduced tau phosphorylation on T123 and T427 and also on additional pathological sites (S262/S356 and S202/T205/S208) in vitro and in cell models. The TAOK inhibitor also decreased tau phosphorylation in differentiated primary cortical neurons without affecting markers of synapse and neuron health. Notably, TAOK activity also co-localised with tangles in post-mortem frontotemporal lobar degeneration (FTLD) brain tissue. Furthermore, the TAOK inhibitor decreased tau phosphorylation in induced pluripotent stem cell derived neurons from FTLD patients, as well as cortical neurons from a transgenic mouse model of tauopathy (Tau35 mice). Our results demonstrate that abnormal TAOK activity is present at pre-tangles and tangles in tauopathies and that TAOK inhibition effectively decreases tau phosphorylation on pathological sites. Thus, TAOKs may represent a novel target to reduce or prevent tau-associated neurodegeneration in tauopathies.

PRAK, a novel protein kinase regulated by the p38 MAP kinase.

PubMed Central

New, L; Jiang, Y; Zhao, M; Liu, K; Zhu, W; Flood, L J; Kato, Y; Parry, G C; Han, J

1998-01-01

We have identified and cloned a novel serine/ threonine kinase, p38-regulated/activated protein kinase (PRAK). PRAK is a 471 amino acid protein with 20-30% sequence identity to the known MAP kinase-regulated protein kinases RSK1/2/3, MNK1/2 and MAPKAP-K2/3. PRAK was found to be expressed in all human tissues and cell lines examined. In HeLa cells, PRAK was activated in response to cellular stress and proinflammatory cytokines. PRAK activity was regulated by p38alpha and p38beta both in vitro and in vivo and Thr182 was shown to be the regulatory phosphorylation site. Activated PRAK in turn phosphorylated small heat shock protein 27 (HSP27) at the physiologically relevant sites. An in-gel kinase assay demonstrated that PRAK is a major stress-activated kinase that can phosphorylate small heat shock protein, suggesting a potential role for PRAK in mediating stress-induced HSP27 phosphorylation in vivo. PMID:9628874

Imatinib and Dasatinib Inhibit Hemangiosarcoma and Implicate PDGFR-β and Src in Tumor Growth12

PubMed Central

Dickerson, Erin B; Marley, Kevin; Edris, Wade; Tyner, Jeffrey W; Schalk, Vidya; MacDonald, Valerie; Loriaux, Marc; Druker, Brian J; Helfand, Stuart C

2013-01-01

Hemangiosarcoma, a natural model of human angiosarcoma, is an aggressive vascular tumor diagnosed commonly in dogs. The documented expression of several receptor tyrosine kinases (RTKs) by these tumors makes them attractive targets for therapeutic intervention using tyrosine kinase inhibitors (TKIs). However, we possess limited knowledge of the effects of TKIs on hemangiosarcoma as well as other soft tissue sarcomas. We report here on the use of the TKIs imatinib and dasatinib in canine hemangiosarcoma and their effects on platelet-derived growth factor receptor β (PDGFR-β) and Src inhibition. Both TKIs reduced cell viability, but dasatinib was markedly more potent in this regard, mediating cytotoxic effects orders of magnitude greater than imatinib. Dasatinib also inhibited the phosphorylation of the shared PDGFR-β target at a concentration approximately 1000 times less than that needed by imatinib and effectively blocked Src phosphorylation. Both inhibitors augmented the response to doxorubicin, suggesting that clinical responses likely will be improved using both drugs in combination; however, dasatinib was significantly (P < .05) more effective in this context. Despite the higher concentrations needed in cell-based assays, imatinib significantly inhibited tumor growth (P < .05) in a tumor xenograft model, highlighting that disruption of PDGFR-β/PDGF signaling may be important in targeting the angiogenic nature of these tumors. Treatment of a dog with spontaneously occurring hemangiosarcoma established that clinically achievable doses of dasatinib may be realized in dogs and provides a means to investigate the effect of TKIs on soft tissue sarcomas in a large animal model. PMID:23544168

PTP1B promotes aggressiveness of breast cancer cells by regulating PTEN but not EMT.

PubMed

Liu, Xue; Chen, Qian; Hu, Xu-Gang; Zhang, Xian-Chao; Fu, Ti-Wei; Liu, Qing; Liang, Yan; Zhao, Xi-Long; Zhang, Xia; Ping, Yi-Fang; Bian, Xiu-Wu

2016-10-01

Metastasis is a complicated, multistep process and remains the major cause of cancer-related mortality. Exploring the molecular mechanisms underlying tumor metastasis is crucial for development of new strategies for cancer prevention and treatment. In this study, we found that protein tyrosine phosphatase 1B (PTP1B) promoted breast cancer metastasis by regulating phosphatase and tensin homolog (PTEN) but not epithelial-mesenchymal transition (EMT). By detecting PTP1B expression of the specimens from 128 breast cancer cases, we found that the level of PTP1B was higher in breast cancer tissues than the corresponding adjacent normal tissues. Notably, PTP1B was positively associated with lymph node metastasis (LNM) and estrogen receptor (ER) status. In vitro, disturbing PTP1B expression obviously attenuated cell migration and invasion. On the contrary, PTP1B overexpression significantly increased migration and invasion of breast cancer cells. Mechanistically, PTP1B knockdown upregulated PTEN, accompanied with an abatement of AKT phosphorylation and the expression of matrix metalloproteinase 2 (MMP2) and MMP7. Conversely, forced expression of PTP1B reduced PTEN and increased AKT phosphorylation as well as the expression of MMP2 and MMP7. Notably, neither EMT nor stemness of breast cancer cells was regulated by PTP1B. We also found that PTP1B acted as an independent prognostic factor and predicted poor prognosis in ER-positive breast cancer patients. Taken together, our findings provide advantageous evidence for the development of PTP1B as a potential therapeutic target for breast cancer, especially for ER-positive breast cancer patients.

Prognostic significance of phosphorylated RON in esophageal squamous cell carcinoma.

PubMed

Hui, Marco K C; Lai, Kenneth K Y; Chan, Kwok Wah; Luk, John M; Lee, Nikki P; Chung, Yvonne; Cheung, Leo C; Srivastava, Gopesh; Tsao, Sai Wah; Tang, Johnny C; Law, Simon

2012-09-01

Esophageal squamous cell carcinoma (ESCC) is the most common type of esophageal cancer. RON is a transmembrane receptor overexpressed in various cancers; however, the clinical significance of its phosphorylated form (pRON) is not fully deciphered. This report is the first to investigate the expression and clinical significance of pRON in human ESCC. Quantitative polymerase chain reaction revealed an up-regulation of RON mRNA in 70% (7/10) of ESCC tissues when compared to the adjacent nontumor tissues. An overexpression of pRON protein was found in most of the ESCC cell lines studied (4/5) when compared to two non-neoplastic esophageal epithelial cells using immunoblot. In 64 ESCC tissues, pRON was localized at the cell membrane, cytoplasm and nucleus in 15 (23.4%), 63 (98.4%) and 61 (95.3%) cases using immunohistochemistry. Patients having high expression of cytoplasmic pRON significantly associated with shorter median survival when compared to those with low expression (25.41 months vs. 14.43 months), suggesting cytoplasmic pRON as a potential marker for poor prognosis in ESCC patients.

Impaired Cerebral Mitochondrial Oxidative Phosphorylation Function in a Rat Model of Ventricular Fibrillation and Cardiopulmonary Resuscitation

PubMed Central

Fu, Yue; Xu, Wen; Jiang, Longyuan; Huang, Zitong

2014-01-01

Postcardiac arrest brain injury significantly contributes to mortality and morbidity in patients suffering from cardiac arrest (CA). Evidence that shows that mitochondrial dysfunction appears to be a key factor in tissue damage after ischemia/reperfusion is accumulating. However, limited data are available regarding the cerebral mitochondrial dysfunction during CA and cardiopulmonary resuscitation (CPR) and its relationship to the alterations of high-energy phosphate. Here, we sought to identify alterations of mitochondrial morphology and oxidative phosphorylation function as well as high-energy phosphates during CA and CPR in a rat model of ventricular fibrillation (VF). We found that impairment of mitochondrial respiration and partial depletion of adenosine triphosphate (ATP) and phosphocreatine (PCr) developed in the cerebral cortex and hippocampus following a prolonged cardiac arrest. Optimal CPR might ameliorate the deranged phosphorus metabolism and preserve mitochondrial function. No obvious ultrastructural abnormalities of mitochondria have been found during CA. We conclude that CA causes cerebral mitochondrial dysfunction along with decay of high-energy phosphates, which would be mitigated with CPR. This study may broaden our understanding of the pathogenic processes underlying global cerebral ischemic injury and provide a potential therapeutic strategy that aimed at preserving cerebral mitochondrial function during CA. PMID:24696844

Leishmania infection inhibits macrophage motility by altering F-actin dynamics and the expression of adhesion complex proteins

PubMed Central

de Menezes, Juliana Perrone Bezerra; Koushik, Amrita; Das, Satarupa; Guven, Can; Siegel, Ariel; Laranjeira-Silva, Maria Fernanda; Losert, Wolfgang; Andrews, Norma W.

2016-01-01

Leishmania is an intracellular protozoan parasite that causes a broad spectrum of clinical manifestations, ranging from self-healing skin lesions to fatal visceralizing disease. As the host cells of choice for all species of Leishmania, macrophages are critical for the establishment of infections. How macrophages contribute to parasite homing to specific tissues and how parasites modulate macrophage function is still poorly understood. In this study we show that L. amazonensis infection inhibits macrophage roaming motility. The reduction in macrophage speed is not dependent on particle load or on factors released by infected macrophages. L. amazonensis-infected macrophages also show reduced directional migration in response to the chemokine MCP-1. We found that infected macrophages have lower levels of total paxillin, phosphorylated paxillin and phosphorylated FAK when compared to non-infected macrophages, indicating abnormalities in the formation of signaling adhesion complexes that regulate motility. Analysis of the dynamics of actin polymerization at peripheral sites also revealed a markedly enhanced F-actin turnover frequency in L. amazonensis-infected macrophages. Thus, Leishmania infection inhibits macrophage motility by altering actin dynamics and impairing the expression of proteins that function in plasma membrane-extracellular matrix interactions. PMID:27641840

Pin1 promotes transforming growth factor-beta-induced migration and invasion.

PubMed

Matsuura, Isao; Chiang, Keng-Nan; Lai, Chen-Yu; He, Dongming; Wang, Guannan; Ramkumar, Romila; Uchida, Takafumi; Ryo, Akihide; Lu, Kunping; Liu, Fang

2010-01-15

Transforming growth factor-beta (TGF-beta) regulates a wide variety of biological activities. It induces potent growth-inhibitory responses in normal cells but promotes migration and invasion of cancer cells. Smads mediate the TGF-beta responses. TGF-beta binding to the cell surface receptors leads to the phosphorylation of Smad2/3 in their C terminus as well as in the proline-rich linker region. The serine/threonine phosphorylation sites in the linker region are followed by the proline residue. Pin1, a peptidyl-prolyl cis/trans isomerase, recognizes phosphorylated serine/threonine-proline motifs. Here we show that Smad2/3 interacts with Pin1 in a TGF-beta-dependent manner. We further show that the phosphorylated threonine 179-proline motif in the Smad3 linker region is the major binding site for Pin1. Although epidermal growth factor also induces phosphorylation of threonine 179 and other residues in the Smad3 linker region the same as TGF-beta, Pin1 is unable to bind to the epidermal growth factor-stimulated Smad3. Further analysis suggests that phosphorylation of Smad3 in the C terminus is necessary for the interaction with Pin1. Depletion of Pin1 by small hairpin RNA does not significantly affect TGF-beta-induced growth-inhibitory responses and a number of TGF-beta/Smad target genes analyzed. In contrast, knockdown of Pin1 in human PC3 prostate cancer cells strongly inhibited TGF-beta-mediated migration and invasion. Accordingly, TGF-beta induction of N-cadherin, which plays an important role in migration and invasion, is markedly reduced when Pin1 is depleted in PC3 cells. Because Pin1 is overexpressed in many cancers, our findings highlight the importance of Pin1 in TGF-beta-induced migration and invasion of cancer cells.

Common elements in interleukin 4 and insulin signaling pathways in factor-dependent hematopoietic cells.

PubMed

Wang, L M; Keegan, A D; Li, W; Lienhard, G E; Pacini, S; Gutkind, J S; Myers, M G; Sun, X J; White, M F; Aaronson, S A

1993-05-01

Interleukin 4 (IL-4), insulin, and insulin-like growth factor I (IGF-I) efficiently induced DNA synthesis in the IL-3-dependent murine myeloid cell lines FDC-P1 and FDC-P2. Although these factors could not individually sustain long-term growth of these lines, a combination of IL-4 with either insulin or IGF-I did support continuous growth. The principal tyrosine-phosphorylated substrate observed in FDC cells stimulated with IL-4, previously designated 4PS, was of the same size (170 kDa) as the major substrate phosphorylated in response to insulin or IGF-I. These substrates had phosphopeptides of the same size when analyzed by digestion with Staphylococcus aureus V8 protease, and each tightly associated with the 85-kDa component of phosphatidylinositol 3-kinase after factor stimulation. IRS-1, the principal substrate phosphorylated in response to insulin or IGF-I stimulation in nonhematopoietic cells, is similar in size to 4PS. However, anti-IRS-1 antibodies failed to efficiently precipitate 4PS, and some phosphopeptides generated by V8 protease digestion of IRS-1 were distinct in size from the phosphopeptides of 4PS. Nevertheless, IL-4, insulin, and IGF-I were capable of stimulating tyrosine phosphorylation of IRS-1 in FDC cells that expressed this substrate as a result of transfection. These findings indicate that (i) IL-4, insulin, and IGF-I use signal transduction pathways in FDC lines that have at least one major feature in common, the rapid tyrosine phosphorylation of 4PS, and (ii) insulin and IGF-I stimulation of hematopoietic cell lines leads to the phosphorylation of a substrate that may be related to but is not identical to IRS-1.

Common elements in interleukin 4 and insulin signaling pathways in factor-dependent hematopoietic cells.

PubMed Central

Wang, L M; Keegan, A D; Li, W; Lienhard, G E; Pacini, S; Gutkind, J S; Myers, M G; Sun, X J; White, M F; Aaronson, S A

1993-01-01

Interleukin 4 (IL-4), insulin, and insulin-like growth factor I (IGF-I) efficiently induced DNA synthesis in the IL-3-dependent murine myeloid cell lines FDC-P1 and FDC-P2. Although these factors could not individually sustain long-term growth of these lines, a combination of IL-4 with either insulin or IGF-I did support continuous growth. The principal tyrosine-phosphorylated substrate observed in FDC cells stimulated with IL-4, previously designated 4PS, was of the same size (170 kDa) as the major substrate phosphorylated in response to insulin or IGF-I. These substrates had phosphopeptides of the same size when analyzed by digestion with Staphylococcus aureus V8 protease, and each tightly associated with the 85-kDa component of phosphatidylinositol 3-kinase after factor stimulation. IRS-1, the principal substrate phosphorylated in response to insulin or IGF-I stimulation in nonhematopoietic cells, is similar in size to 4PS. However, anti-IRS-1 antibodies failed to efficiently precipitate 4PS, and some phosphopeptides generated by V8 protease digestion of IRS-1 were distinct in size from the phosphopeptides of 4PS. Nevertheless, IL-4, insulin, and IGF-I were capable of stimulating tyrosine phosphorylation of IRS-1 in FDC cells that expressed this substrate as a result of transfection. These findings indicate that (i) IL-4, insulin, and IGF-I use signal transduction pathways in FDC lines that have at least one major feature in common, the rapid tyrosine phosphorylation of 4PS, and (ii) insulin and IGF-I stimulation of hematopoietic cell lines leads to the phosphorylation of a substrate that may be related to but is not identical to IRS-1. Images Fig. 2 Fig. 3 Fig. 4 Fig. 5 Fig. 6 PMID:7683417

Activation of phosphatidylinositol-3-kinase by platelet-derived growth factor and insulin-like growth factor-1 is inhibited by a transmembrane phosphotyrosine phosphatase.

PubMed

Way, B A; Mooney, R A

1993-12-15

Expression of the transmembrane phosphotyrosine phosphatase (PTPase) CD45 has been shown to inhibit hormone-dependent tyrosine phosphorylation and mitogenesis (Mooney, R. A., Freund, G. G., Way, B. A., and Bordwell, K. L. (1992) J. Biol. Chem. 267, 23443-23446). Here the impact of PTPase expression on insulin-like growth factor-1 (IGF-1) and platelet-derived growth factor- (PDGF) dependent activation of PI-3-K was investigated. In PTPase+ cells, IGF-1 and PDGF-dependent PI-3-K activity in antiphosphotyrosine immunoprecipitates was decreased by 62 +/- 13 and 46 +/- 17%, respectively, compared to control cells. Similar decreases in PI-3-K activity associated with anti-PDGF receptor and anti-insulin receptor substrate-1 (IRS-1) immunoprecipitates were also observed. Association of PI-3-K with the hormone-activated PDGF receptor decreased approximately 55%, paralleling its loss of activation in PTPase+ cells. Tyrosine phosphorylation of the 85-kDa subunit of PI-3-K was also inhibited. Similarly, IGF-1 dependent tyrosine phosphorylation of IRS-1 was decreased by 45%, and its association with PI-3-K was decreased by 65% in PTPase+ cells. Finally, PDGF-dependent tyrosine phosphorylation of phospholipase C-gamma 1 and GTPase-activating protein was reduced by 60-70% in the PTPase+ cells as was tyrosine phosphorylation of the PDGF receptor associated with these proteins. In summary, expression of a transmembrane PTPase decreased hormone-dependent PI-3-K activation, tyrosine phosphorylation of receptor substrates, and their association with signaling complexes. These data support a role for transmembrane PTPases in the regulation of receptor signal transduction pathways.

[Protective effect of thalidomide on ALI induced by paraquat poisoning in rats and its mechanism].

PubMed

Liu, Tao; Xie, Yuan; Xu, Mengtong; Zheng, Fenshuang

2017-11-01

To investigate the protective effect of thalidomide on acute lung injury (ALI) induced by paraquat (PQ) poisoning in rats and its possible mechanism. Sixty SPF Wistar rats were randomly divided into six groups with 10 rats in each group. The rat model of PQ poisoning was reproduced by intraperitoneal injection of PQ solution 20 mg/kg (PQ model group), and the rats were treated by intraperitoneal injection of gradient thalidomide (50, 100, 200 mg/kg treatment groups) 30 minutes later continuously for 3 days. The normal saline (NS) control group and thalidomide control group (thalidomide 200 mg/kg) were established. After 3 days, the abdominal aorta blood was collected, and the superoxide dismutase (SOD) activity was determined by hydroxylamine method, serum malondialdehyde (MDA) content was determined by thiobarbituric acid method. The rats were sacrificed for lung tissue, the levels of tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) were determined by enzyme-linked immunosorbent assay (ELISA). The phosphorylation levels of p65 and inhibitor-α of nuclear factor-κB (NF-κB) (IκB-α), which were the NF-κB signaling pathway proteins, were determined by Western Blot. The pathological changes in lung tissue were observed under light microscope by hematoxylin-eosin (HE) staining. Under microscope, obvious congestion of pulmonary interstitial and alveolar septum, a large number of inflammatory cells infiltration and thickened alveolar wall were observed after 3 days of PQ poisoning, and the congestion of pulmonary interstitial and alveolar septum, edema and inflammatory cells infiltration in the lung tissue were significantly reduced after treatment of 50, 100, 200 mg/kg thalidomide, but compared with NS control group, there was still a small amount of edema fluid, inflammatory cells and erythrocytes in the lungs tissue. Compared with the NS control group, serum MDA content and the levels of TNF-α and IL-6, and the phosphorylation of p65 and IκB-α in lung tissue were significantly increased after PQ exposure, and the activity of serum SOD was significantly decreased. Treatment with 50, 100, 200 mg/kg thalidomide could significantly reduce the levels of MDA, TNF-α, IL-6, and phosphorylation of IκB-α and p65, and increase SOD activity, in a dose-dependent manner, and the levels were significantly different from PQ model group [MDA (mmol/L): 8.26±1.20, 6.72±1.18, 5.51±1.44 vs. 9.02±1.03, TNF-α (ng/mg): 3.00±0.14, 1.84±0.18, 1.58±0.11 vs. 3.30±0.14, IL-6 (ng/mg): 1.26±0.04, 1.06±0.04, 0.97±0.08 vs. 1.97±0.07, p-p65/p65: 6.01±0.35, 3.64±0.15, 2.89±0.18 vs. 6.34±0.23, p-IκB-α/IκB-α: 2.27±0.13, 2.14±0.22, 1.52±0.14 vs. 2.96±0.20, SOD (kU/L): 195.7±19.3, 207.1±25.6, 225.8±23.1 vs. 188.2±26.6, all P < 0.05]. There was no significant effect on lung by 200 mg/kg thalidomide alone. Thalidomide has a protective effect on ALI induced by PQ poisoning in rats in a dose-dependent manner, the mechanism may be achieved by reducing the level of oxygen free radicals, reducing the inflammatory factor and inhibiting the IκB-α/NF-κB signal pathway activation.

TRB3 gene silencing activates AMPK in adipose tissue with beneficial metabolic effects in obese and diabetic rats.

PubMed

Sun, Xiaoyan; Song, Ming; Wang, Hui; Zhou, Huimin; Wang, Feng; Li, Ya; Zhang, Yun; Zhang, Wei; Zhong, Ming; Ti, Yun

2017-06-17

Our previous study had suggested Tribbles homolog 3 (TRB3) might be involved in metabolic syndrome via adipose tissue. Given prior studies, we sought to determine whether TRB3 plays a major role in adipocytes and adipose tissue with beneficial metabolic effects in obese and diabetic rats. Fully differentiated 3T3-L1 adipocytes were incubated to induce insulin resistant adipocytes. Forty male Sprague-Dawley rats were all fed high-fat (HF) diet. Type 2 diabetic rat model was induced by high-fat diet and low-dose streptozotocin (STZ). Compared with control group, in insulin resistant adipocytes, protein levels of insulin receptor substrate-1(IRS-1), glucose transporter 4(GLUT4) and phosphorylated-AMP-activated protein kinase (p-AMPK)were reduced, TRB3 protein level and triglyceride level were significantly increased, glucose uptake was markedly decreased. TRB3 silencing alleviated adipocytes insulin resistance. With TRB3 gene silencing, protein levels of IRS-1, GLUT4 and p-AMPK were significantly increased in adipocytes. TRB3 gene silencing decreased blood glucose, ameliorated insulin sensitivity and adipose tissue remodeling in diabetic rats. TRB3 silencing decreased triglyceride, increased glycogen simultaneously in diabetic epididymal and brown adipose tissues (BAT). Consistently, p-AMPK levels were increased in diabetic epididymal adipose tissue, and BAT after TRB3-siRNA treatment. TRB3silencing increased phosphorylation of Akt in liver, and improved liver insulin resistance. Copyright © 2017. Published by Elsevier Inc.

Exploring the interactions of EGFR with phosphorylated Mig6 by molecular dynamics simulations and MM-PBSA calculations.

PubMed

Zhang, Yue; Zheng, Qing-Chuan

2018-06-14

Mig6, a negative regulator, directly binds to epidermal growth factor receptor (EGFR), including Mig6-segment1 and Mig6-segment2. Mig6 requires phosphorylation of Y394 on Mig6-segment2 in order to inhibit EGFR. Two phosphorylation pathways for Y394 have been previously reported and the first way may phosphorylate Y394 primed by Y395 phosphorylation. Besides, the binding mechanism of phosphorylated Mig6-segment2 with EGFR has not been elucidated clearly. Focused on EGFR complex with phosphorylated Mig6-segment2, molecular dynamics (MD) simulations were performed to explore the interactions of Mig6-segment2 with EGFR. Our results indicate a probable phosphorylation pathway on Y394 and some key residues of EGFR play important roles in binding to phosphorylated Mig6-segment2. In addition, a special L-shaped structure was found to be possibly associated with irreversible inhibition of EGFR by Mig6. Our work can give meaningful information to better understand the phosphorylation pathways for Y394 and the interactions of EGFR binding to phosphorylated Mig6-segment2. Copyright © 2018 Elsevier Ltd. All rights reserved.

Cell biology of Smad2/3 linker region phosphorylation in vascular smooth muscle.

PubMed

Rezaei, Hossein B; Kamato, Danielle; Ansari, Ghazaleh; Osman, Narin; Little, Peter J

2012-08-01

The transforming growth factor (TGF)-β superfamily of ligands regulates a diverse set of cellular functions. Transforming growth factor-β induces its biological effects through Type I and Type II transmembrane receptors that have serine/threonine kinase activities and weak tyrosine kinase activity. In vascular smooth muscle, TGF-β binds to the TGF-β Type II receptor (TβRII) at the cell surface, recruiting the Type I receptor (TβRI) to form a heterocomplex. Consequently, after phosphorylation and activation of TβRI, the transcription factors receptor activated (R-) Smad2 and Smad3 are recruited and activated through phosphorylation of C terminal residues. Overall, Smad2/3 and co-Smad4 have similar structures consisting of three regions an N-terminal MH1 domain, a C-terminal MH2 domain and a central linker region. Phosphorylation of the Smad linker region appears to have an important role in the regulation of Smad activity and function. The mitogen-activated protein kinase (MAPK) family, CDK2, CDK4 and calcium-calmodulin dependent kinase are the main kinases that phosphorylate sites in the linker region. The role of the linker region includes enabling the formation of Smad homo-oligomers and provision of phosphorylation sites for MAPK and other kinases. In some instances, linker region phosphorylation regulates the inhibition of the nuclear translocation of Smads. In the present review, we describe TGF-β signalling through Smad2/3 and the importance of the linker region in the regulation and expression of genes induced by TGF-β superfamily ligands in the context of vascular smooth muscle. © 2011 The Authors. Clinical and Experimental Pharmacology and Physiology © 2011 Blackwell Publishing Asia Pty Ltd.

Src kinase regulation by phosphorylation and dephosphorylation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Roskoski, Robert

2005-05-27

Src and Src-family protein-tyrosine kinases are regulatory proteins that play key roles in cell differentiation, motility, proliferation, and survival. The initially described phosphorylation sites of Src include an activating phosphotyrosine 416 that results from autophosphorylation, and an inhibiting phosphotyrosine 527 that results from phosphorylation by C-terminal Src kinase (Csk) and Csk homologous kinase. Dephosphorylation of phosphotyrosine 527 increases Src kinase activity. Candidate phosphotyrosine 527 phosphatases include cytoplasmic PTP1B, Shp1 and Shp2, and transmembrane enzymes include CD45, PTP{alpha}, PTP{epsilon}, and PTP{lambda}. Dephosphorylation of phosphotyrosine 416 decreases Src kinase activity. Thus far PTP-BL, the mouse homologue of human PTP-BAS, has been shownmore » to dephosphorylate phosphotyrosine 416 in a regulatory fashion. The platelet-derived growth factor receptor protein-tyrosine kinase mediates the phosphorylation of Src Tyr138; this phosphorylation has no direct effect on Src kinase activity. The platelet-derived growth factor receptor and the ErbB2/HER2 growth factor receptor protein-tyrosine kinases mediate the phosphorylation of Src Tyr213 and activation of Src kinase activity. Src kinase is also a substrate for protein-serine/threonine kinases including protein kinase C (Ser12), protein kinase A (Ser17), and CDK1/cdc2 (Thr34, Thr46, and Ser72). Of the three protein-serine/threonine kinases, only phosphorylation by CDK1/cdc2 has been demonstrated to increase Src kinase activity. Although considerable information on the phosphoprotein phosphatases that catalyze the hydrolysis of Src phosphotyrosine 527 is at hand, the nature of the phosphatases that mediate the hydrolysis of phosphotyrosine 138 and 213, and phosphoserine and phosphothreonine residues has not been determined.« less

BCR mediated signal transduction in immature and mature B cells.

PubMed

Koncz, Gábor; Bodor, Csaba; Kövesdi, Dorottya; Gáti, Róbert; Sármay, Gabriella

2002-06-03

Ligation of B cell receptors (BCR) on immature B cells may induce apoptosis, while in mature B cells it stimulates cell activation and growth. The signaling pathway regulating the differential functional response, death or survival of the B cell is not fully characterized. We have tested the intracellular signaling requirement of these processes using B cells isolated from the spleen of irradiated auto-reconstituted (transitional immature B cells) and untreated mice (mature B cells), respectively. We compared the BCR induced intracellular [Ca2+] transient, protein tyrosine phosphorylation and ERK phosphorylation, furthermore, the activation of Elk-1 and CREB transcription factors. The BCR induced rise of intracellular [Ca2+] did not significantly differ in the two populations, only a slight difference in the late phase of the response was observed. Immature B cells responded with a maximum tyrosine phosphorylation to a five times lower dose of anti-IgM compared to the mature population. Most importantly, we have found a significant difference in the tyrosine phosphorylation of the Gab family adaptor proteins, Gab1/2. In contrast to mature B cells, crosslinking of BCR on immature B cells did not induce tyrosine phosphorylation of Gab2, thus the Gab2-organized signal amplification complex could not be produced. Furthermore, we detected a significant difference in the kinetics of BCR induced ERK, Elk-1 and CREB phosphorylation. In immature B cells, ERK was transiently phosphorylated, ceasing after 120 min, while in mature cells, ERK phosphorylation was sustained. Elk-1 and CREB activation was also transient in immature B cells, followed the kinetics of ERK phosphorylation. The lack of sustained Erk1/2 activation suppresses the transcription factors necessary for the proliferation signal. Since ERK is regulated by the phosphorylated Gab1/2, these data demonstrate that BCR triggered phosphorylation and signal amplification of Gab1/2 is a critical step in a life or death decision of B cells.

Effects of heparin-binding epidermal growth factor-like growth factor on cell repopulation and signal transduction in periodontal ligament cells after scratch wounding in vitro.

PubMed

Lee, J S; Kim, J M; Hong, E K; Kim, S-O; Yoo, Y-J; Cha, J-H

2009-02-01

A growing amount of attention has been placed on periodontal regeneration and wound healing for periodontal therapy. This study was conducted in an effort to determine the effects of heparin-binding epidermal growth factor-like growth factor on cell repopulation and signal transduction in periodontal ligament cells after scratch wounding in vitro. Human periodontal ligament cells were acquired from explant tissue of human healthy periodontal ligament. After the wounding of periodontal ligament cells, the change in expression of heparin-binding epidermal growth factor-like growth factor and epidermal growth factor receptors 1-4 mRNA was assessed. The effects of heparin-binding epidermal growth factor-like growth factor on periodontal ligament cell proliferation and repopulation were assessed in vitro via the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and by photographing the injuries, respectively. Extracellular signal-regulated kinase (Erk)1/2, p38 and Akt phosphorylation was characterized via western blotting. Scratch wounding resulted in a significant up-regulation of heparin-binding epidermal growth factor-like growth factor mRNA expression, whereas wounding had no effect on the expression levels of epidermal growth factor receptors 1-4. Interestingly, no expression of epidermal growth factor receptors 2 and 4 was detectable prior to or after wounding. Heparin-binding epidermal growth factor-like growth factor treatment promoted the proliferation and repopulation of periodontal ligament cells. The scratch wounding also stimulated the phosphorylation of Erk1/2 and p38, but not of Akt, in periodontal ligament cells, and heparin-binding epidermal growth factor-like growth factor treatment applied after wounding amplified and extended the activations of Erk1/2 and p38, but not of Akt. Furthermore, Erk1/2 inhibition blocked the process of cell repopulation induced by heparin-binding epidermal growth factor-like growth factor, whereas the inhibition of p38 delayed the process. These results indicate that heparin-binding epidermal growth factor-like growth factor may constitute a critical factor in the wound healing of human periodontal ligament cells by a mechanism that requires the activation of Erk1/2 via specific interaction with epidermal growth factor receptor 1.

SRC-DEPENDENT PHOSPHORYLATION OF THE EPIDERMAL GROWTH FACTOR RECEPTOR ON TYROSINE 845 IS REQUIRED FOR ZINC-INDUCED RAS ACTIVATION

EPA Science Inventory

Src-dependent Phosphorylation of the Epidermal Growth Factor Receptor on Tyrosine 845 Is Required for Zinc-induced Ras Activation
Weidong Wu 1 , Lee M. Graves 2 , Gordon N. Gill 3 , Sarah J. Parsons 4 , and James M. Samet 5
1 Center for Environmental Medicine and Lung Biolo...

Type 1 receptor tyrosine kinases are differentially phosphorylated in mammary carcinoma and differentially associated with steroid receptors.

PubMed Central

Bacus, S. S.; Chin, D.; Yarden, Y.; Zelnick, C. R.; Stern, D. F.

1996-01-01

The neu/erbB-2/HER-2 proto-oncogene is amplified and/or overexpressed in up to 30% of mammary carcinomas and has been variably correlated with poor prognosis. The signaling activity of the encoded receptor tyrosine kinase is regulated by interactions with other type 1 receptors and their ligands. We have used a novel approach, phosphorylation-sensitive anti-Neu antibodies, to quantify signaling by Neu and epidermal growth factor receptor in a panel of frozen sections of mammary carcinoma specimens. We also determined the relationship of Neu, phosphorylated Neu (and epidermal growth factor receptor), and phosphotyrosine to the expression of Neu-related receptors (epidermal growth factor receptor, HER-3, and HER-4) and to prognostic factors (estrogen and progesterone receptor). We found that tyrosine phosphorylation of Neu (and hence signaling activity) is highly variable among mammary carcinomas. Neu and HER-4 were associated with divergent correlates, suggesting that they have profoundly different biological activities. These results have implications for etiology of mammary carcinoma for clinical evaluation of mammary carcinoma patients, and for development of Neu-targeted therapeutic strategies. Images Figure 1 Figure 2 PMID:8579117

The Phosphatidylinositol 3-Kinase/Akt Pathway Regulates Transforming Growth Factor-β Signaling by Destabilizing Ski and Inducing Smad7*

PubMed Central

Band, Arja M.; Björklund, Mia; Laiho, Marikki

2009-01-01

Ski is an oncoprotein that negatively regulates transforming growth factor (TGF)-β signaling. It acts as a transcriptional co-repressor by binding to TGF-β signaling molecules, Smads. Efficient TGF-β signaling is facilitated by rapid proteasome-mediated degradation of Ski by TGF-β. Here we report that Ski is phosphorylated by Akt/PKB kinase. Akt phosphorylates Ski on a highly conserved Akt motif at threonine 458 both in vitro and in vivo. The phosphorylation of Ski at threonine 458 is induced by Akt pathway activators including insulin, insulin-like growth factor-1, and hepatocyte growth factor. The phosphorylation of Ski causes its destabilization and reduces Ski-mediated inhibition of expression of another negative regulator of TGF-β, Smad7. Induction of Smad7 levels leads to inactivation of TGF-β receptors and TGF-β signaling cascade, as indicated by reduced induction of TGF-β target p15. Therefore, Akt modulates TGF-β signaling by temporarily adjusting the levels of two TGF-β pathway negative regulators, Ski and Smad7. These novel findings demonstrate that Akt pathway activation directly impacts TGF-β pathway. PMID:19875456

Glycogen synthase kinase-3: a key kinase in retinal neuron apoptosis in early diabetic retinopathy.

PubMed

Li, Zhaohui; Ma, Ling; Chen, Xiaodong; Li, Yonghao; Li, Shiyi; Zhang, Jinglin; Lu, Lin

2014-01-01

Diabetes-related pathogenic factors can cause retinal ganglion cell (RGC) apoptosis, but the specific mechanism is not very clear. The aim of this study is to investigate the correlation between glycogen synthase kinase-3 (GSK-3) activation and retinal neuron apoptosis. In an in vitro experiment, the number of apoptotic RGC-5 cells differentiated by staurosporine was evaluated via flow cytometry and nuclei staining using Hoechst 33258. GSK-3 phosphorylation and caspase-3 activation in RGC-5 cells after serum deprivation were determined using Western blotting. Mitochondrial membrane potential was detected using the dye 5, 5', 6, 6'tetrachloro-1, 1', 3, 3'-tetrethyl benzimidalyl carbocyanine iodide, and reactive oxygen species (ROS) levels were measured with dihydroethidium. In an in vivo experiment, the number of apoptotic retinal neurons was evaluated via terminal transferase dUTP nick-end labeling (TUNEL), and GSK-3 phosphorylation was determined using Western blotting, in the retinal nerve epithelial tissue of rats in which diabetes was induced by intravenous tail-vein injection of streptozotocin for 4 weeks. The levels of phosphorylated Ser21/9 in GSK-3α/β and p-T308/S473-AKT were lower and the cleaved caspase-3 levels were higher in the serum-deprived model (P < 0.05). Lithium chloride treatment was associated with a slower rate of apoptosis, increased mitochondrial membrane potential, and decreased ROS levels in differentiated RGC-5 cells (P < 0.05). The level of blood glucose and the number of TUNEL-positive cells in the whole-mounted retinas were higher (P < 0.01), and the levels of phosphorylated Ser21/9 in GSK-3α/β and body weight were lower (P < 0.05). However, the thickness of the retinal nerve epithelial layer was not significantly less in diabetic rats compared with control group. Lithium chloride intravitreal injection increased the levels of phosphorylated Ser21/9 in GSK-3α/β and decreased TUNEL-positive cells in the whole-mounted retinas. GSK-3 kinase is closely related to retinal neuron apoptosis, and the application of the GSK-3 inhibitor lithium chloride can reduce retinal neuron apoptosis in early diabetic retinopathy.

TNFα- and IKKβ-mediated TANK/I-TRAF phosphorylation: implications for interaction with NEMO/IKKγ and NF-κB activation

PubMed Central

Bonif, Marianne; Meuwis, Marie-Alice; Close, Pierre; Benoit, Valérie; Heyninck, Karen; Chapelle, Jean-Paul; Bours, Vincent; Merville, Marie-Paule; Piette, Jacques; Beyaert, Rudi; Chariot, Alain

2005-01-01

Pro-inflammatory cytokines trigger signalling cascades leading to NF-κB (nuclear factor-κB)-dependent gene expression through IKK [IκB (inhibitory κB) kinase]-dependent phosphorylation and subsequent degradation of the IκB proteins and via induced phosphorylation of p65. These signalling pathways rely on sequentially activated kinases which are assembled by essential and non-enzymatic scaffold proteins into functional complexes. Here, we show that the pro-inflammatory cytokine TNFα (tumour necrosis factor α) promotes TANK [TRAF (TNF receptor-associated factor) family member associated NF-κB activator] recruitment to the IKK complex via a newly characterized C-terminal zinc finger. Moreover, we show that TANK is phosphorylated by IKKβ upon TNFα stimulation and that this modification negatively regulates TANK binding to NEMO (NF-κB essential modulator). Interestingly, reduced TANK expression by RNA interference attenuates TNFα-mediated induction of a subset of NF-κB target genes through decreased p65 transactivation potential. Therefore the scaffold protein TANK is required for the cellular response to TNFα by connecting upstream signalling molecules to the IKKs and p65, and its subsequent IKKβ-mediated phosphorylation may be a mechanism to terminate the TANK-dependent wave of NF-κB activation. PMID:16336209

FTS is responsible for radiation-induced nuclear phosphorylation of EGFR and repair of DNA damage in cervical cancer cells.

PubMed

Muthusami, Sridhar; Prabakaran, D S; Yu, Jae-Ran; Park, Woo-Yoon

2015-02-01

Radiation-induced nuclear stabilization and phosphorylation of epidermal growth factor receptor (EGFR) confers radioresistance. Understanding of the factor(s) regulating the nuclear stabilization and phosphorylation of EGFR is important for the modulation of radioresistance. Present study was designed to delineate the regulation of EGFR nuclear stabilization and phosphorylation by fused toes homolog (FTS), an oncoprotein, which is responsible for the radioresistance in cervical cancer cells. A cervical cancer cell line, ME180 was used. Radiation-induced change in the levels of EGFR, p-EGFR and FTS were evaluated in the cytoplasm and nucleus using Western blot analyses. FTS was silenced using siRNA-based approach. Interaction between EGFR and FTS was assessed using immunofluorescence and immunoprecipitation analyses. Double-strand breaks (DSB) of DNA were assessed using γ H2AX. Radiation increased the levels of EGFR and FTS in the cytoplasm and nucleus. EGFR and FTS are in physical association with each other and are co-localized in the cells. FTS silencing largely reduced the nuclear stabilization and phosphorylation of EGFR and DNA-protein kinase along with increased initial and residual DSBs. EGFR and FTS physically associate with each other and FTS silencing radiosensitizes ME180 cells through impaired nuclear EGFR signaling.

Stk1-mediated phosphorylation stimulates the DNA-binding properties of the Staphylococcus aureus SpoVG transcriptional factor.

PubMed

Bischoff, Markus; Brelle, Solène; Minatelli, Sabrina; Molle, Virginie

2016-05-13

The stage V sporulation protein G (SpoVG) homolog of Staphylococcus aureus is a modulator of virulence factor synthesis and antibiotic resistance in this clinically important gram-positive pathogen. Here we demonstrate that SpoVG can be phosphorylated by the staphylococcal Ser/Thr protein kinase Stk1 and that phosphorylation positively affects its DNA-binding properties. Mass spectrometric analyses and site directed mutagenesis identified Thr4, Thr13, Thr24 and Ser41 as phospho-acceptors. Stk1-mediated phosphorylation markedly enhanced the DNA binding activity of SpoVG towards the promoter regions of target genes such as capA, lip, and nuc1. Similarly, trans-complementation of the S. aureus ΔyabJ-spoVG mutant SM148 with a SpoVG derivative that mimics constitutive phosphorylation, SpoVG_Asp, exhibited capA, lip, and nuc1 transcript levels that were comparable to the levels seen with the wild-type, whereas trans-complementation with a phosphoablative variant of SpoVG (SpoVG_Ala) produced transcript levels similar to the ones seen in SM148. Our data suggest that the expression/activity of this transcription factor is tightly controlled in S. aureus by transcriptional, post-transcriptional and post-translational mechanisms. Copyright © 2016 Elsevier Inc. All rights reserved.

Activation of the protein tyrosine phosphatase SHP2 via the interleukin-6 signal transducing receptor protein gp130 requires tyrosine kinase Jak1 and limits acute-phase protein expression.

PubMed

Schaper, F; Gendo, C; Eck, M; Schmitz, J; Grimm, C; Anhuf, D; Kerr, I M; Heinrich, P C

1998-11-01

Stimulation of the interleukin-6 (IL-6) signalling pathway occurs via the IL-6 receptor-glycoprotein 130 (IL-6R-gp130) receptor complex and results in the regulation of acute-phase protein genes in liver cells. Ligand binding to the receptor complex leads to tyrosine phosphorylation and activation of Janus kinases (Jak), phosphorylation of the signal transducing subunit gp130, followed by recruitment and phosphorylation of the signal transducer and activator of transcription factors STAT3 and STAT1 and the src homology domain (SH2)-containing protein tyrosine phosphatase (SHP2). The tyrosine phosphorylated STAT factors dissociate from the receptor, dimerize and translocate to the nucleus where they bind to enhancer sequences of IL-6 target genes. Phosphorylated SHP2 is able to bind growth factor receptor bound protein (grb2) and thus might link the Jak/STAT pathway to the ras/raf/mitogen-activated protein kinase pathway. Here we present data on the dose-dependence, kinetics and kinase requirements for SHP2 phosphorylation after the activation of the signal transducer, gp130, of the IL-6-type family receptor complex. When human fibrosarcoma cell lines deficient in Jak1, Jak2 or tyrosine kinase 2 (Tyk2) were stimulated with IL-6-soluble IL-6R complexes it was found that only in Jak1-, but not in Jak 2- or Tyk2-deficient cells, SHP2 activation was greatly impaired. It is concluded that Jak1 is required for the tyrosine phosphorylation of SHP2. This phosphorylation depends on Tyr-759 in the cytoplasmatic domain of gp130, since a Tyr-759-->Phe exchange abrogates SHP2 activation and in turn leads to elevated and prolonged STAT3 and STAT1 activation as well as enhanced acute-phase protein gene induction. Therefore, SHP2 plays an important role in acute-phase gene regulation.

Abscisic acid-activated SNRK2 protein kinases function in the gene-regulation pathway of ABA signal transduction by phosphorylating ABA response element-binding factors.

PubMed

Kobayashi, Yuhko; Murata, Michiharu; Minami, Hideyuki; Yamamoto, Shuhei; Kagaya, Yasuaki; Hobo, Tokunori; Yamamoto, Akiko; Hattori, Tsukaho

2005-12-01

The plant hormone abscisic acid (ABA) induces gene expression via the ABA-response element (ABRE) present in the promoters of ABA-regulated genes. A group of bZIP proteins have been identified as ABRE-binding factors (ABFs) that activate transcription through this cis element. A rice ABF, TRAB1, has been shown to be activated via ABA-dependent phosphorylation. While a large number of signalling factors have been identified that are involved in stomatal regulation by ABA, relatively less is known about the ABA-signalling pathway that leads to gene expression. We have shown recently that three members of the rice SnRK2 protein kinase family, SAPK8, SAPK9 and SAPK10, are activated by ABA signal as well as by hyperosmotic stress. Here we show that transient overexpression in cultured cell protoplasts of these ABA-activated SnRK2 protein kinases leads to the activation of an ABRE-regulated promoter, suggesting that these kinases are involved in the gene-regulation pathway of ABA signalling. We further show several lines of evidence that these ABA-activated SnRK2 protein kinases directly phosphorylate TRAB1 in response to ABA. Kinetic analysis of SAPK10 activation and TRAB1 phosphorylation indicated that the latter immediately followed the former. TRAB1 was found to be phosphorylated not only in response to ABA, but also in response to hyperosmotic stress, which was interpreted as the consequence of phosphorylation of TRAB1 by hyperosmotically activated SAPKs. Physical interaction between TRAB1 and SAPK10 in vivo was demonstrated by a co-immunoprecipitation experiment. Finally, TRAB1 was phosphorylated in vitro by the ABA-activated SnRK2 protein kinases at Ser102, which is phosphorylated in vivo in response to ABA and is critical for the activation function.

Protein kinase A can block EphA2 receptor–mediated cell repulsion by increasing EphA2 S897 phosphorylation

PubMed Central

Barquilla, Antonio; Lamberto, Ilaria; Noberini, Roberta; Heynen-Genel, Susanne; Brill, Laurence M.; Pasquale, Elena B.

2016-01-01

The EphA2 receptor tyrosine kinase plays key roles in tissue homeostasis and disease processes such as cancer, pathological angiogenesis, and inflammation through two distinct signaling mechanisms. EphA2 “canonical” signaling involves ephrin-A ligand binding, tyrosine autophosphorylation, and kinase activity; EphA2 “noncanonical” signaling involves phosphorylation of serine 897 (S897) by AKT and RSK kinases. To identify small molecules counteracting EphA2 canonical signaling, we developed a high-content screening platform measuring inhibition of ephrin-A1–induced PC3 prostate cancer cell retraction. Surprisingly, most hits from a screened collection of pharmacologically active compounds are agents that elevate intracellular cAMP by activating G protein–coupled receptors such as the β2-adrenoceptor. We found that cAMP promotes phosphorylation of S897 by protein kinase A (PKA) as well as increases the phosphorylation of several nearby serine/threonine residues, which constitute a phosphorylation hotspot. Whereas EphA2 canonical and noncanonical signaling have been viewed as mutually exclusive, we show that S897 phosphorylation by PKA can coexist with EphA2 tyrosine phosphorylation and block cell retraction induced by EphA2 kinase activity. Our findings reveal a novel paradigm in EphA2 function involving the interplay of canonical and noncanonical signaling and highlight the ability of the β2-adrenoceptor/cAMP/PKA axis to rewire EphA2 signaling in a subset of cancer cells. PMID:27385333

Ferulic acid attenuates focal cerebral ischemia-induced decreases in p70S6 kinase and S6 phosphorylation.

PubMed

Koh, Phil-Ok

2013-10-25

Ferulic acid exhibits neuroprotective effects against focal cerebral ischemia. PI3/K and Akt signaling pathways play an essential role in protecting against cerebral ischemia. Mammalian target of rapamycin (mTOR), a major downstream target of Akt, regulates p70S6 kinase and S6, both of which are involved in ribosomal biogenesis and protein synthesis. I investigated whether ferulic acid regulates mTOR, p70S6 kinase, and S6 phosphorylation during brain ischemic injury. Rats were treated immediately with vehicle or ferulic acid (100mg/kg, i.v.) after middle cerebral artery occlusion (MCAO). Brains tissues were removed at 24h after the onset of MCAO and the cerebral cortex regions were collected. Ferulic acid reduced the MCAO-induced infarct volume. I showed previously that ferulic acid prevents the MCAO injury-induced decrease of Akt phosphorylation. In this study, MCAO injury induced decreases in mTOR, p70S6 kinase, and S6 phosphorylation levels, while ferulic acid attenuated the injury-induced decreases. Immunohistochemical staining demonstrated that ferulic acid prevented the MCAO-induced reduction in the number of positive cells for phosphorylated p70S6 kinase and phosphorylated S6. These findings suggest that ferulic acid has a neuroprotective function against focal cerebral ischemia by modulating p70S6 kinase expression and S6 phosphorylation. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

Mechanisms of integrin-vascular endothelial growth factor receptor cross-activation in angiogenesis.

PubMed

Mahabeleshwar, Ganapati H; Feng, Weiyi; Reddy, Kumar; Plow, Edward F; Byzova, Tatiana V

2007-09-14

The functional responses of endothelial cells are dependent on signaling from peptide growth factors and the cellular adhesion receptors, integrins. These include cell adhesion, migration, and proliferation, which, in turn, are essential for more complex processes such as formation of the endothelial tube network during angiogenesis. This study identifies the molecular requirements for the cross-activation between beta3 integrin and tyrosine kinase receptor 2 for vascular endothelial growth factor (VEGF) receptor (VEGFR-2) on endothelium. The relationship between VEGFR-2 and beta3 integrin appears to be synergistic, because VEGFR-2 activation induces beta3 integrin tyrosine phosphorylation, which, in turn, is crucial for VEGF-induced tyrosine phosphorylation of VEGFR-2. We demonstrate here that adhesion- and growth factor-induced beta3 integrin tyrosine phosphorylation are directly mediated by c-Src. VEGF-stimulated recruitment and activation of c-Src and subsequent beta3 integrin tyrosine phosphorylation are critical for interaction between VEGFR-2 and beta3 integrin. Moreover, c-Src mediates growth factor-induced beta3 integrin activation, ligand binding, beta3 integrin-dependent cell adhesion, directional migration of endothelial cells, and initiation of angiogenic programming in endothelial cells. Thus, the present study determines the molecular mechanisms and consequences of the synergism between 2 cell surface receptor systems, growth factor receptor and integrins, and opens new avenues for the development of pro- and antiangiogenic strategies.

Matrix Metalloproteinase Responsive Delivery of Myostatin Inhibitors.

PubMed

Braun, Alexandra C; Gutmann, Marcus; Ebert, Regina; Jakob, Franz; Gieseler, Henning; Lühmann, Tessa; Meinel, Lorenz

2017-01-01

The inhibition of myostatin - a member of the transforming growth factor (TGF-β) family - drives regeneration of functional skeletal muscle tissue. We developed a bioresponsive drug delivery system (DDS) linking release of a myostatin inhibitor (MI) to inflammatory flares of myositis to provide self-regulated MI concentration gradients within tissues of need. A protease cleavable linker (PCL) - responding to MMP upregulation - is attached to the MI and site-specifically immobilized on microparticle surfaces. The PCL disintegrated in a matrix metalloproteinase (MMP) 1, 8, and particularly MMP-9 concentration dependent manner, with MMP-9 being an effective surrogate biomarker correlating with the activity of myositis. The bioactivity of particle-surface bound as well as released MI was confirmed by luciferase suppression in stably transfected HEK293 cells responding to myostatin induced SMAD phosphorylation. We developed a MMP-responsive DDS for MI delivery responding to inflammatory flare of a diseased muscle matching the kinetics of MMP-9 upregulation, with MMP-9 kinetics matching (patho-) physiological myostatin levels. ᅟ: Graphical Abstract Schematic illustration of the matrix metalloproteinase responsive delivery system responding to inflammatory flares of muscle disease. The protease cleavable linker readily disintegrates upon entry into the diseased tissue, therby releasing the mystatin inhibitor.

c-Abl phosphorylation of Yin Yang 1's conserved tyrosine 254 in the spacer region modulates its transcriptional activity.

PubMed

Daraiseh, Susan I; Kassardjian, Ari; Alexander, Karen E; Rizkallah, Raed; Hurt, Myra M

2018-05-25

Yin Yang 1 (YY1) is a multifunctional transcription factor that can activate or repress transcription depending on the promotor and/or the co-factors recruited. YY1 is phosphorylated in various signaling pathways and is critical for different biological functions including embryogenesis, apoptosis, proliferation, cell-cycle regulation and tumorigenesis. Here we report that YY1 is a substrate for c-Abl kinase phosphorylation at conserved residue Y254 in the spacer region. Pharmacological inhibition of c-Abl kinase by imatinib, nilotinib and GZD824, knock-down of c-Abl using siRNA, and the use of c-Abl kinase-dead drastically reduces tyrosine phosphorylation of YY1. Both radioactive and non-radioactive in vitro kinase assays, as well as co-immunoprecipitation in different cell lines, show that the target of c-Abl phosphorylation is tyrosine residue 254. c-Abl phosphorylation has little effect on YY1 DNA binding ability or cellular localization in asynchronous cells. However, functional studies reveal that c-Abl mediated phosphorylation of YY1 regulates YY1's transcriptional ability in vivo. In conclusion, we demonstrate the novel role of c-Abl kinase in regulation of YY1's transcriptional activity, linking YY1 regulation with c-Abl tyrosine kinase signaling pathways. Copyright © 2018. Published by Elsevier B.V.

Huntingtin-Interacting Protein 1 Phosphorylation by Receptor Tyrosine Kinases

PubMed Central

Ames, Heather M.; Wang, Anmin A.; Coughran, Alanna; Evaul, Kristen; Huang, Sha; Graves, Chiron W.; Soyombo, Abigail A.

2013-01-01

Huntingtin-interacting protein 1 (HIP1) binds inositol lipids, clathrin, actin, and receptor tyrosine kinases (RTKs). HIP1 is elevated in many tumors, and its expression is prognostic in prostate cancer. HIP1 overexpression increases levels of the RTK epidermal growth factor receptor (EGFR) and transforms fibroblasts. Here we report that HIP1 is tyrosine phosphorylated in the presence of EGFR and platelet-derived growth factor β receptor (PDGFβR) as well as the oncogenic derivatives EGFRvIII, HIP1/PDGFβR (H/P), and TEL/PDGFβR (T/P). We identified a four-tyrosine “HIP1 phosphorylation motif” (HPM) in the N-terminal region of HIP1 that is required for phosphorylation mediated by both EGFR and PDGFβR but not by the oncoproteins H/P and T/P. We also identified a tyrosine residue (Y152) within the HPM motif of HIP1 that inhibits HIP1 tyrosine phosphorylation. The HPM tyrosines are conserved in HIP1's only known mammalian relative, HIP1-related protein (HIP1r), and are also required for HIP1r phosphorylation. Tyrosine-to-phenylalanine point mutations in the HPM of HIP1 result in proapoptotic activity, indicating that an intact HPM may be necessary for HIP1's role in cellular survival. These data suggest that phosphorylation of HIP1 by RTKs in an N-terminal region contributes to the promotion of cellular survival. PMID:23836884

Huntingtin-interacting protein 1 phosphorylation by receptor tyrosine kinases.

PubMed

Ames, Heather M; Wang, Anmin A; Coughran, Alanna; Evaul, Kristen; Huang, Sha; Graves, Chiron W; Soyombo, Abigail A; Ross, Theodora S

2013-09-01

Huntingtin-interacting protein 1 (HIP1) binds inositol lipids, clathrin, actin, and receptor tyrosine kinases (RTKs). HIP1 is elevated in many tumors, and its expression is prognostic in prostate cancer. HIP1 overexpression increases levels of the RTK epidermal growth factor receptor (EGFR) and transforms fibroblasts. Here we report that HIP1 is tyrosine phosphorylated in the presence of EGFR and platelet-derived growth factor β receptor (PDGFβR) as well as the oncogenic derivatives EGFRvIII, HIP1/PDGFβR (H/P), and TEL/PDGFβR (T/P). We identified a four-tyrosine "HIP1 phosphorylation motif" (HPM) in the N-terminal region of HIP1 that is required for phosphorylation mediated by both EGFR and PDGFβR but not by the oncoproteins H/P and T/P. We also identified a tyrosine residue (Y152) within the HPM motif of HIP1 that inhibits HIP1 tyrosine phosphorylation. The HPM tyrosines are conserved in HIP1's only known mammalian relative, HIP1-related protein (HIP1r), and are also required for HIP1r phosphorylation. Tyrosine-to-phenylalanine point mutations in the HPM of HIP1 result in proapoptotic activity, indicating that an intact HPM may be necessary for HIP1's role in cellular survival. These data suggest that phosphorylation of HIP1 by RTKs in an N-terminal region contributes to the promotion of cellular survival.

Solanum tuberosum StCDPK1 is regulated by miR390 at the posttranscriptional level and phosphorylates the auxin efflux carrier StPIN4 in vitro, a potential downstream target in potato development.

PubMed

Santin, Franco; Bhogale, Sneha; Fantino, Elisa; Grandellis, Carolina; Banerjee, Anjan K; Ulloa, Rita M

2017-02-01

Among many factors that regulate potato tuberization, calcium and calcium-dependent protein kinases (CDPKs) play an important role. CDPK activity increases at the onset of tuber formation with StCDPK1 expression being strongly induced in swollen stolons. However, not much is known about the transcriptional and posttranscriptional regulation of StCDPK1 or its downstream targets in potato development. To elucidate further, we analyzed its expression in different tissues and stages of the life cycle. Histochemical analysis of StCDPK1::GUS (β-glucuronidase) plants demonstrated that StCDPK1 is strongly associated with the vascular system in stems, roots, during stolon to tuber transition, and in tuber sprouts. In agreement with the observed GUS profile, we found specific cis-acting elements in StCDPK1 promoter. In silico analysis predicted miR390 to be a putative posttranscriptional regulator of StCDPK1. Quantitative real time-polymerase chain reaction (qRT-PCR) analysis showed ubiquitous expression of StCDPK1 in different tissues which correlated well with Western blot data except in leaves. On the contrary, miR390 expression exhibited an inverse pattern in leaves and tuber eyes suggesting a possible regulation of StCDPK1 by miR390. This was further confirmed by Agrobacterium co-infiltration assays. In addition, in vitro assays showed that recombinant StCDPK1-6xHis was able to phosphorylate the hydrophilic loop of the auxin efflux carrier StPIN4. Altogether, these results indicate that StCDPK1 expression is varied in a tissue-specific manner having significant expression in vasculature and in tuber eyes; is regulated by miR390 at posttranscriptional level and suggest that StPIN4 could be one of its downstream targets revealing the overall role of this kinase in potato development. © 2016 Scandinavian Plant Physiology Society.

Insulin-like growth factor (IGF)-I controls prostate fibromuscular development: IGF-I inhibition prevents both fibromuscular and glandular development in eugonadal mice.

PubMed

Kleinberg, David L; Ruan, Weifeng; Yee, Douglas; Kovacs, Kalman T; Vidal, Sergio

2007-03-01

Although antiandrogen therapy has been shown effective in treating prostatic tumors, it is relatively ineffective in treating benign prostatic hyperplasia (BPH). In an attempt to understand better the role of androgens in the development of the normal prostate and BPH, we studied the relative effects of testosterone and IGF-I on the development of the two compartments of the prostate in castrated IGF-I((-/-)) male mice. Here we report that IGF-I stimulated the development of the fibromuscular compartment, but testosterone inhibited it (stromal epithelial ratio 2.17 vs. 0.83, respectively; P < 0.001). Testosterone also impaired IGF-I induced insulin receptor substrate-1 phosphorylation and cell division, and increased apoptosis in fibromuscular tissue. In sharp contrast IGF-I and testosterone both stimulated the development of the glandular compartment individually and together. The combined effects were either additive or synergistic on compartment size, cell division, insulin receptor substrate-1 phosphorylation, and probasin production. Together they also had a greater inhibitory effect on apoptosis in gland tissue. To determine whether IGF-I inhibition would inhibit both fibromuscular and glandular compartments, we tested the effect of IGF binding protein-1 on prostate development in two different models: castrated Ames dwarf mice and eugonadal normal male mice. IGF binding protein-1 blocked bovine GH-induced fibromuscular and glandular development in both. It also inhibited epithelial cell division and increased apoptosis in both prostate compartments in the eugonadal mice. The observed discordance between IGF-I and testosterone control of prostate compartment development might explain the relative failure of 5alpha-reductase inhibition in BPH and why testosterone inhibition might theoretically reduce gland volume but increase fibromuscular tissue. The work also provides a rationale for considering IGF-I inhibition as therapy for BPH to reduce the size of both prostate compartments.

A sustained increase in plasma NEFA upregulates the Toll-like receptor network in human muscle

PubMed Central

Hussey, Sophie E.; Lum, Helen; Alvarez, Andrea; Cipriani, Yolanda; Garduño-Garcia, José de Jesús; Anaya, Luis; Dube, John; Musi, Nicolas

2014-01-01

Aims/hypothesis Insulin-sensitive tissues (muscle, liver) of individuals with obesity and type 2 diabetes mellitus are in a state of low-grade inflammation, characterised by increased Toll-like receptor (TLR) expression and TLR-driven signalling. However, the cause of this mild inflammatory state is unclear. We tested the hypothesis that a prolonged mild increase in plasma NEFA will increase TLR expression and TLR-driven signalling (nuclear factor κB [NFκB] and mitogen-activated kinase [MAPK]) and impair insulin action in muscle of lean healthy individuals. Methods Twelve lean, normal-glucose-tolerant participants were randomised to receive a 48 h infusion (30 ml/h) of saline or Intralipid followed by a euglycaemic–hyperinsulinaemic clamp. Vastus lateralis muscle biopsies were performed before and during the clamp. Results Lipid infusion impaired insulin-stimulated IRS-1 tyrosine phosphorylation and reduced peripheral insulin sensitivity (p < 0.01). The elevation in circulating NEFA increased expression of TLR3, TLR4 and TLR5, and several MAPK (MAPK8, MAP4K4, MAP2K3) and inhibitor of κB kinase-NFκB (CHUK [IKKA], c-REL [REL] and p65 [RELA, NFKB3,p65]) signalling genes (p < 0.05). The lipid infusion also increased extracellular signal-regulated kinase (ERK) phosphorylation (p < 0.05) and tended to reduce the content of nuclear factor of light polypeptide gene enhancer in B cells inhibitor α (p = 0.09). The muscle content of most diacyglycerol, ceramide and acylcarnitine species was unaffected. In summary, insulin resistance induced by prolonged low-dose lipid infusion occurs together with increased TLR-driven inflammatory signalling and impaired insulin-stimulated IRS-1 tyrosine phosphorylation. Conclusions/interpretation A sustained, mild elevation in plasma NEFA is sufficient to increase TLR expression and TLR-driven signalling (NFκB and MAPK) in lean individuals. The activation of this pathway by NEFA may be involved in the pathogenesis of insulin resistance in humans. PMID:24337154

Platelet-Derived Growth Factor Receptor Activation Promotes the Prodestructive Invadosome-Forming Phenotype of Synoviocytes from Patients with Rheumatoid Arthritis.

PubMed

Charbonneau, Martine; Lavoie, Roxane R; Lauzier, Annie; Harper, Kelly; McDonald, Patrick P; Dubois, Claire M

2016-04-15

Fibroblast-like synoviocytes (FLS) play a major role in invasive joint destruction in rheumatoid arthritis (RA). This prodestructive phenotype has been shown to involve autocrine TGF-β that triggers formation of matrix-degrading invadosomes through molecular mechanisms that are not fully elucidated. The platelet-derived growth factor (PDGF) receptor (PDGFR) family of receptor tyrosine kinases (RTK) has been shown to cooperate with TGF-β in various pathological conditions. We therefore sought to determine whether RTK activity played a role in invadosome biogenesis. We demonstrated that, among the common RTKs, PDGFR-αβ was specifically phosphorylated in FLS from RA patients. Phosphorylation of PDGFR-αβ was also elevated in RA synovial tissues. Interference with PDGFR activation or PDGF neutralization inhibited invadosome formation in RA synoviocytes, indicating the presence of an autocrine PDGFR activation loop that involved endogenous PDGF. Among the PDGF-A-D isoforms, only PDGF-B was found both significantly elevated in FLS lines from RA patients, and related to high-invadosome forming cells. Addition of TGF-β upregulated invadosome formation, PDGF-B mRNA expression, and phosphorylation of PDGFR. All of these functions were efficiently suppressed by TGF-β neutralization or interference with the Smad/TβR1or PI3K/Akt pathway. Among the class 1 PI3K family proteins known to be expressed in RA synoviocytes, PI3Kα was selectively involved in PDGF-B expression, whereas both PI3Kα and PI3Kδ participated in invadosome formation. Our findings demonstrate that PDGFR is a critical RTK required for the prodestructive phenotype of RA synovial cells. They also provide evidence for an association between autocrine TGF-β and PDGFR-mediated invadosome formation in RA synoviocytes that involves the production of PDGF-B induced by TGF-β. Copyright © 2016 by The American Association of Immunologists, Inc.

Long-term treatment of bile duct-ligated rats with rapamycin (sirolimus) significantly attenuates liver fibrosis: analysis of the underlying mechanisms.

PubMed

Biecker, Erwin; De Gottardi, Andrea; Neef, Markus; Unternährer, Matthias; Schneider, Vreni; Ledermann, Monika; Sägesser, Hans; Shaw, Sidney; Reichen, Jürg

2005-06-01

Rapamycin is an immunosuppressant with antiproliferative properties. We investigated whether rapamycin treatment of bile duct-ligated (BDL) rats is capable of inhibiting liver fibrosis and thereby affecting hemodynamics. Following BDL, rats were treated for 28 days with rapamycin (BDL SIR). BDL animals without drug treatment (BDL CTR) and sham-operated animals served as controls. After 28 days, hemodynamics were measured, and livers were harvested for histology/immunohistochemistry. Liver mRNA levels of transforming growth factor (TGF)-beta1, connective tissue growth factor (CTGF), platelet-derived growth factor (PDGF)-beta, cyclin-dependent kinase inhibitor p27(kip) (p27), and cyclin-dependent kinase inhibitor p21(WAF1/CIP1) (p21) were quantified by real-time polymerase chain reaction. Liver protein levels of p27, p21, p70 S6 kinase (p70(s6k)), phosphorylated p70(s6k) (p-p70(s6k)), eukaryotic initiation factor 4E-binding protein (4E-BP1), p-4E-BP1 (Thr37/46), and p-4E-BP1 (Ser65/Thr70) were determined by Western blotting. Portal vein pressure was lower in BDL SIR than in BDL CTR animals. Volume fractions of connective tissue, bile duct epithelial, and desmin- and actin-positive cells were lower in BDL SIR than in BDL CTR rats. On the mRNA level, TGF-beta1, CTGF, and PDGF were decreased by rapamycin. p27 and p21 mRNA did not differ. On the protein level, rapamycin increased p27 and decreased p21 levels. Levels of nonphosphorylated p70(s6k) and 4E-BP1 did not vary between groups, but levels of p-p70(s6k) were decreased by rapamycin. Rapamycin had no effect on p-4E-BP1 (Thr37/46) and p-4E-BP1 (Ser65/Thr70) levels. In BDL rats, rapamycin inhibits liver fibrosis and ameliorates portal hypertension. This is paralleled by decreased levels of TGF-beta1, CTGF, and PDGF. Rapamycin influences the cell cycle by up-regulation of p27, down-regulation of p21, and inhibition of p70(s6k) phosphorylation.

A structural model of anti-anti-[sigma] inhibition by a two-component receiver domain: the PhyR stress response regulator

DOE Office of Scientific and Technical Information (OSTI.GOV)

Herrou, Julien; Foreman, Robert; Fiebig, Aretha

2012-05-09

PhyR is a hybrid stress regulator conserved in {alpha}-proteobacteria that contains an N-terminal {sigma}-like (SL) domain and a C-terminal receiver domain. Phosphorylation of the receiver domain is known to promote binding of the SL domain to an anti-{sigma} factor. PhyR thus functions as an anti-anti-{sigma} factor in its phosphorylated state. We present genetic evidence that Caulobacter crescentus PhyR is a phosphorylation-dependent stress regulator that functions in the same pathway as {sigma}{sup T} and its anti-{sigma} factor, NepR. Additionally, we report the X-ray crystal structure of PhyR at 1.25 {angstrom} resolution, which provides insight into the mechanism of anti-anti-{sigma} regulation. Directmore » intramolecular contact between the PhyR receiver and SL domains spans regions {sigma}{sub 2} and {sigma}{sub 4}, likely serving to stabilize the SL domain in a closed conformation. The molecular surface of the receiver domain contacting the SL domain is the structural equivalent of {alpha}4-{beta}5-{alpha}5, which is known to undergo dynamic conformational change upon phosphorylation in a diverse range of receiver proteins. We propose a structural model of PhyR regulation in which receiver phosphorylation destabilizes the intramolecular interaction between SL and receiver domains, thereby permitting regions {sigma}{sub 2} and {sigma}{sub 4} in the SL domain to open about a flexible connector loop and bind anti-{sigma} factor.« less

A structural model of anti-anti-[sigma];#963; inhibition by a two-component receiver domain: the PhyR stress response regulator

DOE Office of Scientific and Technical Information (OSTI.GOV)

Herrou, Julien; Foreman, Robert; Fiebig, Aretha

2012-03-30

PhyR is a hybrid stress regulator conserved in {alpha}-proteobacteria that contains an N-terminal {sigma}-like (SL) domain and a C-terminal receiver domain. Phosphorylation of the receiver domain is known to promote binding of the SL domain to an anti-{sigma} factor. PhyR thus functions as an anti-anti-{sigma} factor in its phosphorylated state. We present genetic evidence that Caulobacter crescentus PhyR is a phosphorylation-dependent stress regulator that functions in the same pathway as {sigma}{sup T} and its anti-{sigma} factor, NepR. Additionally, we report the X-ray crystal structure of PhyR at 1.25 {angstrom} resolution, which provides insight into the mechanism of anti-anti-{sigma} regulation. Directmore » intramolecular contact between the PhyR receiver and SL domains spans regions {sigma}{sub 2} and {sigma}{sub 4}, likely serving to stabilize the SL domain in a closed conformation. The molecular surface of the receiver domain contacting the SL domain is the structural equivalent of {alpha}4-{beta}5-{alpha}5, which is known to undergo dynamic conformational change upon phosphorylation in a diverse range of receiver proteins. We propose a structural model of PhyR regulation in which receiver phosphorylation destabilizes the intramolecular interaction between SL and receiver domains, thereby permitting regions {sigma}{sub 2} and {sigma}{sub 4} in the SL domain to open about a flexible connector loop and bind anti-{sigma} factor.« less

Global gene expression profiling of brown to white adipose tissue transformation in sheep reveals novel transcriptional components linked to adipose remodeling.

PubMed

Basse, Astrid L; Dixen, Karen; Yadav, Rachita; Tygesen, Malin P; Qvortrup, Klaus; Kristiansen, Karsten; Quistorff, Bjørn; Gupta, Ramneek; Wang, Jun; Hansen, Jacob B

2015-03-19

Large mammals are capable of thermoregulation shortly after birth due to the presence of brown adipose tissue (BAT). The majority of BAT disappears after birth and is replaced by white adipose tissue (WAT). We analyzed the postnatal transformation of adipose in sheep with a time course study of the perirenal adipose depot. We observed changes in tissue morphology, gene expression and metabolism within the first two weeks of postnatal life consistent with the expected transition from BAT to WAT. The transformation was characterized by massively decreased mitochondrial abundance and down-regulation of gene expression related to mitochondrial function and oxidative phosphorylation. Global gene expression profiling demonstrated that the time points grouped into three phases: a brown adipose phase, a transition phase and a white adipose phase. Between the brown adipose and the transition phase 170 genes were differentially expressed, and 717 genes were differentially expressed between the transition and the white adipose phase. Thirty-eight genes were shared among the two sets of differentially expressed genes. We identified a number of regulated transcription factors, including NR1H3, MYC, KLF4, ESR1, RELA and BCL6, which were linked to the overall changes in gene expression during the adipose tissue remodeling. Finally, the perirenal adipose tissue expressed both brown and brite/beige adipocyte marker genes at birth, the expression of which changed substantially over time. Using global gene expression profiling of the postnatal BAT to WAT transformation in sheep, we provide novel insight into adipose tissue plasticity in a large mammal, including identification of novel transcriptional components linked to adipose tissue remodeling. Moreover, our data set provides a useful resource for further studies in adipose tissue plasticity.

[Energy reactions in the skeletal muscles of rats after a flight on the Kosmos-1129 biosatellite].

PubMed

Mailian, E S; Buravkova, L B; Kokoreva, L V

1983-01-01

The polarographic analysis of biological oxidation in rat skeletal muscles after the 18.5-day flight revealed changes specific for the flight animals: oxidative phosphorylation uncoupling, distinct inertness of energy accumulation 10 hrs after recovery. Tissue respiration inhibition occurred in both flight and synchronous rats suggesting the effect of other than weightlessness factors. In the flight animals the parameters of energy metabolism returned to the prelaunch level within a longer (29 days) time than in the synchronous rats (6 days). Muscles of different function (predominance of fast or slow fibers) showed similar responses of energy metabolism to weightlessness, i. e. inhibition of the intensity and decrease of the energy efficiency of oxidative processes.

In-depth Qualitative and Quantitative Profiling of Tyrosine Phosphorylation Using a Combination of Phosphopeptide Immunoaffinity Purification and Stable Isotope Dimethyl Labeling*

PubMed Central

Boersema, Paul J.; Foong, Leong Yan; Ding, Vanessa M. Y.; Lemeer, Simone; van Breukelen, Bas; Philp, Robin; Boekhorst, Jos; Snel, Berend; den Hertog, Jeroen; Choo, Andre B. H.; Heck, Albert J. R.

2010-01-01

Several mass spectrometry-based assays have emerged for the quantitative profiling of cellular tyrosine phosphorylation. Ideally, these methods should reveal the exact sites of tyrosine phosphorylation, be quantitative, and not be cost-prohibitive. The latter is often an issue as typically several milligrams of (stable isotope-labeled) starting protein material are required to enable the detection of low abundance phosphotyrosine peptides. Here, we adopted and refined a peptidecentric immunoaffinity purification approach for the quantitative analysis of tyrosine phosphorylation by combining it with a cost-effective stable isotope dimethyl labeling method. We were able to identify by mass spectrometry, using just two LC-MS/MS runs, more than 1100 unique non-redundant phosphopeptides in HeLa cells from about 4 mg of starting material without requiring any further affinity enrichment as close to 80% of the identified peptides were tyrosine phosphorylated peptides. Stable isotope dimethyl labeling could be incorporated prior to the immunoaffinity purification, even for the large quantities (mg) of peptide material used, enabling the quantification of differences in tyrosine phosphorylation upon pervanadate treatment or epidermal growth factor stimulation. Analysis of the epidermal growth factor-stimulated HeLa cells, a frequently used model system for tyrosine phosphorylation, resulted in the quantification of 73 regulated unique phosphotyrosine peptides. The quantitative data were found to be exceptionally consistent with the literature, evidencing that such a targeted quantitative phosphoproteomics approach can provide reproducible results. In general, the combination of immunoaffinity purification of tyrosine phosphorylated peptides with large scale stable isotope dimethyl labeling provides a cost-effective approach that can alleviate variation in sample preparation and analysis as samples can be combined early on. Using this approach, a rather complete qualitative and quantitative picture of tyrosine phosphorylation signaling events can be generated. PMID:19770167

Fructose, but not glucose, impairs insulin signaling in the three major insulin-sensitive tissues

PubMed Central

Baena, Miguel; Sangüesa, Gemma; Dávalos, Alberto; Latasa, María-Jesús; Sala-Vila, Aleix; Sánchez, Rosa María; Roglans, Núria; Laguna, Juan Carlos; Alegret, Marta

2016-01-01

Human studies support the relationship between high intake of fructose-sweetened beverages and type 2 diabetes, but there is a debate on whether this effect is fructose-specific or it is merely associated to an excessive caloric intake. Here we investigate the effects of 2 months’ supplementation to female rats of equicaloric 10% w/v fructose or glucose solutions on insulin sensitivity in target tissues. Fructose supplementation caused hepatic deposition of triglycerides and changed the fatty acid profile of this fraction, with an increase in monounsaturated and a decrease in polyunsaturated species, but did not cause inflammation and oxidative stress. Fructose but not glucose-supplemented rats displayed an abnormal glucose tolerance test, and did not show increased phosphorylation of V-akt murine thymoma viral oncogene homolog-2 (Akt) in white adipose tissue and liver after insulin administration. In skeletal muscle, phosphorylation of Akt and of Akt substrate of 160 kDA (AS160) was not impaired but the expression of the glucose transporter type 4 (GLUT4) in the plasma membrane was reduced only in fructose-fed rats. In conclusion, fructose but not glucose supplementation causes fatty liver without inflammation and oxidative stress and impairs insulin signaling in the three major insulin-responsive tissues independently from the increase in energy intake. PMID:27194405

Tissue phosphoproteomics with PolyMAC identifies potential therapeutic targets in a transgenic mouse model of HER2 positive breast cancer

PubMed Central

Searleman, Adam C.; Iliuk, Anton B.; Collier, Timothy S.; Chodosh, Lewis A.; Tao, W. Andy; Bose, Ron

2014-01-01

Altered protein phosphorylation is a feature of many human cancers that can be targeted therapeutically. Phosphopeptide enrichment is a critical step for maximizing the depth of phosphoproteome coverage by MS, but remains challenging for tissue specimens because of their high complexity. We describe the first analysis of a tissue phosphoproteome using polymer-based metal ion affinity capture (PolyMAC), a nanopolymer that has excellent yield and specificity for phosphopeptide enrichment, on a transgenic mouse model of HER2-driven breast cancer. By combining phosphotyrosine immunoprecipitation with PolyMAC, 411 unique peptides with 139 phosphotyrosine, 45 phosphoserine, and 29 phosphothreonine sites were identified from five LC-MS/MS runs. Combining reverse phase liquid chromatography fractionation at pH 8.0 with PolyMAC identified 1571 unique peptides with 1279 phosphoserine, 213 phosphothreonine, and 21 phosphotyrosine sites from eight LC-MS/MS runs. Linear motif analysis indicated that many of the phosphosites correspond to well-known phosphorylation motifs. Analysis of the tyrosine phosphoproteome with the Drug Gene Interaction database uncovered a network of potential therapeutic targets centered on Src family kinases with inhibitors that are either FDA-approved or in clinical development. These results demonstrate that PolyMAC is well suited for phosphoproteomic analysis of tissue specimens. PMID:24723360

Oxygen, pH, and mitochondrial oxidative phosphorylation.

PubMed

Wilson, David F; Harrison, David K; Vinogradov, Sergei A

2012-12-15

The oxygen dependence of mitochondrial oxidative phosphorylation was measured in suspensions of isolated rat liver mitochondria using recently developed methods for measuring oxygen and cytochrome c reduction. Cytochrome-c oxidase (energy conservation site 3) activity of the mitochondrial respiratory chain was measured using an artificial electron donor (N,N,N',N'-tetramethyl-p-phenylenediamine) and ascorbate to directly reduce the cytochrome c, bypassing sites 1 and 2. For mitochondrial suspensions with added ATP, metabolic conditions approximating those in intact cells and decreasing oxygen pressure both increased reduction of cytochrome c and decreased respiratory rate. The kinetic parameters [K(M) and maximal rate (V(M))] for oxygen were determined from the respiratory rates calculated for 100% reduction of cytochrome c. At 22°C, the K(M) for oxygen is near 3 Torr (5 μM), 12 Torr (22 μM), and 18 Torr (32 μM) at pH 6.9, 7.4, and 7.9, respectively, and V(M) corresponds to a turnover number for cytochrome c at 100% reduction of near 80/s and is independent of pH. Uncoupling oxidative phosphorylation increased the respiratory rate at saturating oxygen pressures by twofold and decreased the K(M) for oxygen to <2 Torr at all tested pH values. Mitochondrial oxidative phosphorylation is an important oxygen sensor for regulation of metabolism, nutrient delivery to tissues, and cardiopulmonary function. The decrease in K(M) for oxygen with acidification of the cellular environment impacts many tissue functions and may give transformed cells a significant survival advantage over normal cells at low-pH, oxygen-limited environment in growing tumors.

Warts phosphorylates Mud to promote Pins-mediated mitotic spindle orientation in Drosophila independent of Yorkie

PubMed Central

Dewey, Evan B.; Sanchez, Desiree; Johnston, Christopher A.

2015-01-01

SUMMARY Multicellular animals have evolved conserved signaling pathways that translate cell polarity cues into mitotic spindle positioning to control the orientation of cell division within complex tissue structures. These oriented cell divisions are essential for the development of cell diversity and the maintenance of tissue homeostasis. Despite intense efforts, the molecular mechanisms that control spindle orientation remain incompletely defined. Here we describe a role for the Hippo (Hpo) kinase complex in promoting Partner of Inscuteable (Pins)-mediated spindle orientation. Knockdown of Hpo, Salvador (Sav), or Warts (Wts) each result in a partial loss of spindle orientation, a phenotype previously described following loss of the Pins-binding protein Mushroom body defect (Mud). Similar to orthologs spanning yeast to mammals, Wts kinase localizes to mitotic spindle poles, a prominent site of Mud localization. Wts directly phosphorylates Mud in vitro within its C-terminal coiled-coil domain. This Mud coiled-coil domain directly binds the adjacent Pins-binding domain to dampen the Pins/Mud interaction, and Wts-mediated phosphorylation uncouples this intramolecular Mud interaction. Loss of Wts prevents cortical Pins/Mud association without affecting Mud accumulation at spindle poles, suggesting phosphorylation acts as a molecular switch to specifically activate cortical Mud function. Finally, loss of Wts in Drosophila imaginal disc epithelial cells results in diminished cortical Mud and defective planar spindle orientation. Our results provide new insights into the molecular basis for dynamic regulation of the cortical Pins/Mud spindle positioning complex and highlight a novel link with an essential, evolutionarily-conserved cell proliferation pathway. PMID:26592339

Warts phosphorylates mud to promote pins-mediated mitotic spindle orientation in Drosophila, independent of Yorkie.

PubMed

Dewey, Evan B; Sanchez, Desiree; Johnston, Christopher A

2015-11-02

Multicellular animals have evolved conserved signaling pathways that translate cell polarity cues into mitotic spindle positioning to control the orientation of cell division within complex tissue structures. These oriented cell divisions are essential for the development of cell diversity and the maintenance of tissue homeostasis. Despite intense efforts, the molecular mechanisms that control spindle orientation remain incompletely defined. Here, we describe a role for the Hippo (Hpo) kinase complex in promoting Partner of Inscuteable (Pins)-mediated spindle orientation. Knockdown of Hpo, Salvador (Sav), or Warts (Wts) each result in a partial loss of spindle orientation, a phenotype previously described following loss of the Pins-binding protein Mushroom body defect (Mud). Similar to orthologs spanning yeast to mammals, Wts kinase localizes to mitotic spindle poles, a prominent site of Mud localization. Wts directly phosphorylates Mud in vitro within its C-terminal coiled-coil domain. This Mud coiled-coil domain directly binds the adjacent Pins-binding domain to dampen the Pins/Mud interaction, and Wts-mediated phosphorylation uncouples this intramolecular Mud interaction. Loss of Wts prevents cortical Pins/Mud association without affecting Mud accumulation at spindle poles, suggesting phosphorylation acts as a molecular switch to specifically activate cortical Mud function. Finally, loss of Wts in Drosophila imaginal disc epithelial cells results in diminished cortical Mud and defective planar spindle orientation. Our results provide new insights into the molecular basis for dynamic regulation of the cortical Pins/Mud spindle positioning complex and highlight a novel link with an essential, evolutionarily conserved cell proliferation pathway. Copyright © 2015 Elsevier Ltd. All rights reserved.

Up-Regulation of Bcl-xl by Hepatocyte Growth Factor in Human Mesothelioma Cells Involves ETS Transcription Factors

PubMed Central

Cao, Xiaobo; Littlejohn, James; Rodarte, Charles; Zhang, Lidong; Martino, Benjamin; Rascoe, Philip; Hamid, Kamran; Jupiter, Daniel; Smythe, W. Roy

2009-01-01

Bcl-xl and the hepatocyte growth factor (HGF) receptor c-Met are both highly expressed in mesotheliomas, where they protect cells from apoptosis and can confer resistance to conventional therapeutic agents. In our current study, we investigate a model for the transcriptional control of Bcl-xl that involves ETS transcription factors and the HGF/Met axis. In addition, the effects of activated c-Met on the phosphorylation of the ETS family transcriptional factors were examined. The transient expression of ETS-2 and PU.1 cDNAs in mesothelioma cell lines resulted in an increase in the promoter activity of Bcl-xl and consequently in its mRNA and protein expression levels, whereas the transcriptional repressor Tel suppressed Bcl-xl transcription. The activation of the HGF/Met axis led to rapid phosphorylation of ETS family transcription factors in mesothelioma cells through the mitogen-activated protein kinase pathway and via nuclear accumulation of ETS-2 and PU.1. A chromatin immunoprecipitation assay further demonstrated that the activation of c-Met enhanced the binding of ETS transcriptional factors to the Bcl-x promoter. Finally, we determined the Bcl-xl and phosphorylated c-Met expression levels in mesothelioma patient samples; these data suggest a strong correlation between Bcl-xl and phosphorylated c-Met levels. Taken together, these findings support a role for c-Met as an inhibitor of apoptosis and an activator of Bcl-xl. PMID:19834061

Phloretin attenuates LPS-induced acute lung injury in mice via modulation of the NF-κB and MAPK pathways.

PubMed

Huang, Wen-Chung; Lai, Ching-Long; Liang, Yuan-Ting; Hung, Hui-Chih; Liu, Hui-Chia; Liou, Chian-Jiun

2016-11-01

Phloretin, which can be isolated from apple trees, has demonstrable anti-inflammatory and anti-oxidant effects in macrophages. We previously reported that phloretin could inhibit the inflammatory response and reduce intercellular adhesion molecule 1 (ICAM-1) expression in interleukin (IL)-1β-activated human lung epithelial cells. In the present study we now evaluate whether phloretin exposure could ameliorate lipopolysaccharide (LPS)-induced acute lung injury in mice. Intra-peritoneal injections of phloretin were administered to mice for 7 consecutive days, prior to the induction of lung injury by intra-tracheal administration of LPS. Our subsequent analyses demonstrated that phloretin could significantly suppress LPS-induced neutrophil infiltration of lung tissue, and reduce the levels of IL-6 and tumor necrosis factor (TNF)-α in serum and bronchoalveolar lavage fluid. We also found that phloretin modulated myeloperoxidase activity and superoxide dismutase activity, with decreased gene expression levels for chemokines, proinflammatory cytokines, and ICAM-1 in inflamed lung tissue. Phloretin also significantly reduced the phosphorylation of nuclear factor kappa B (NF-κB) and mitogen-activated protein kinase (MAPK), thus limiting the inflammatory response, while promoting expression of heme oxygenase (HO)-1 and nuclear factor erythroid 2-related factor 2, both of which are cytoprotective. Our findings suggest that, mechanistically, phloretin attenuates the inflammatory and oxidative stress pathways that accompany lung injury in mice via blockade of the NF-κB and MAPK pathways. Copyright © 2016. Published by Elsevier B.V.

Activation of Akt, not connexin 43 protein ubiquitination, regulates gap junction stability.

PubMed

Dunn, Clarence A; Su, Vivian; Lau, Alan F; Lampe, Paul D

2012-01-20

The pore-forming gap junctional protein connexin 43 (Cx43) has a short (1-3 h) half-life in cells in tissue culture and in whole tissues. Although critical for cellular function in all tissues, the process of gap junction turnover is not well understood because treatment of cells with a proteasomal inhibitor results in larger gap junctions but little change in total Cx43 protein whereas lysosomal inhibitors increase total, mostly nonjunctional Cx43. To better understand turnover and identify potential sites of Cx43 ubiquitination, we prepared constructs of Cx43 with different lysines converted to arginines. However, when transfected into cells, a mutant version of Cx43 with all lysines converted to arginines behaved similarly to wild type in the presence of proteasomal and lysosomal inhibitors, indicating that ubiquitination of Cx43 did not appear to be playing a role in gap junction stability. Through the use of inhibitors and dominant negative constructs, we found that Akt (protein kinase B) activity controlled gap junction stability and was necessary to form larger stable gap junctions. Akt activation was increased upon proteasomal inhibition and resulted in phosphorylation of Cx43 at Akt phosphorylation consensus sites. Thus, we conclude that Cx43 ubiquitination is not necessary for the regulation of Cx43 turnover; rather, Akt activity, probably through direct phosphorylation of Cx43, controls gap junction stability. This linkage of a kinase involved in controlling cell survival and growth to gap junction stability may mechanistically explain how gap junctions and Akt play similar regulatory roles.

Yap4 PKA- and GSK3-dependent phosphorylation affects its stability but not its nuclear localization.

PubMed

Pereira, Jorge; Pimentel, Catarina; Amaral, Catarina; Menezes, Regina A; Rodrigues-Pousada, Claudina

2009-12-01

Yap4 is a nuclear-resident transcription factor induced in Saccharomyces cerevisiae when exposed to several stress conditions, which include mild hyperosmotic and oxidative stress, temperature shift or metal exposure. This protein is also phosphorylated. Here we report that this modification is driven by PKA and GSK3. In order to ascertain whether Yap4 is directly or indirectly phosphorylated by PKA, we searched for stress and PKA-related kinases that could phosphorylate Yap4. We show that phosphorylation is independent of the kinases Rim15, Yak1, Sch9, Slt2, Ste20 and Ptk2. In addition, we showed that Yap4 phosphorylation is also abrogated in the triple GSK3 mutant mck1 rim11 yol128c. Furthermore, our data reveal that Yap4 nuclear localization is independent of its phosphorylation state. This protein has several putative phosphorylation sites, but only the mutation of residues T192 and S196 impairs its phosphorylation under different stress conditions. The ability of the non-phosphorylated forms of Yap4 to partially rescue the hog1 severe sensitivity phenotype is not affected, suggesting that Yap4 activity is maintained in the absence of phosphorylation. However, this modification seems to be required for stability of the protein, as the non-phosphorylated form has a shorter half-life than the phosphorylated one.

P‐TEFb goes viral

PubMed Central

Zaborowska, Justyna; Isa, Nur F.

2015-01-01

Positive transcription elongation factor b (P‐TEFb), which comprises cyclin‐dependent kinase 9 (CDK9) kinase and cyclin T subunits, is an essential kinase complex in human cells. Phosphorylation of the negative elongation factors by P‐TEFb is required for productive elongation of transcription of protein‐coding genes by RNA polymerase II (pol II). In addition, P‐TEFb‐mediated phosphorylation of the carboxyl‐terminal domain (CTD) of the largest subunit of pol II mediates the recruitment of transcription and RNA processing factors during the transcription cycle. CDK9 also phosphorylates p53, a tumor suppressor that plays a central role in cellular responses to a range of stress factors. Many viral factors affect transcription by recruiting or modulating the activity of CDK9. In this review, we will focus on how the function of CDK9 is regulated by viral gene products. The central role of CDK9 in viral life cycles suggests that drugs targeting the interaction between viral products and P‐TEFb could be effective anti‐viral agents. PMID:27398404

Circulating autoantibodies to phosphorylated α-enolase are a hallmark of pancreatic cancer.

PubMed

Tomaino, Barbara; Cappello, Paola; Capello, Michela; Fredolini, Claudia; Sperduti, Isabella; Migliorini, Paola; Salacone, Paola; Novarino, Anna; Giacobino, Alice; Ciuffreda, Libero; Alessio, Massimo; Nisticò, Paola; Scarpa, Aldo; Pederzoli, Paolo; Zhou, Weidong; Petricoin Iii, Emanuel F; Liotta, Lance A; Giovarelli, Mirella; Milella, Michele; Novelli, Francesco

2011-01-07

Pancreatic ductal adenocarcinoma (PDAC) has a dismal prognosis and no diagnostic markers have, as of yet, been defined. In PDAC patients, α-enolase (ENOA) is up-regulated and elicits the production of autoantibodies. Here, we analyzed the autoantibody response to post-translational modifications of ENOA in PDAC patients. ENOA isolated from PDAC tissues and cell lines was characterized by two-dimensional electrophoresis (2-DE) Western blot (WB), revealing the expression of six different isoforms (named ENOA1,2,3,4,5,6) whereas only 4 isoforms (ENOA3,4,5,6) were detectable in normal tissues. As assessed by 2-DE WB, 62% of PDAC patients produced autoantibodies to the two more acidic isoforms (ENOA1,2) as opposed to only 4% of controls. Mass spectrometry showed that ENOA1,2 isoforms were phosphorylated on serine 419. ROC analysis demonstrated that autoantibodies to ENOA1,2 usefully complement the diagnostic performance of serum CA19.9 levels, achieving approximately 95% diagnostic accuracy in both advanced and resectable PDAC. Moreover, the presence of autoantibodies against ENOA1,2 correlated with a significantly better clinical outcome in advanced patients treated with standard chemotherapy. In conclusion, our results demonstrate that ENOA phosphorylation is associated with PDAC and induces specific autoantibody production in PDAC patients that may have diagnostic value.

Oxygen, the lead actor in the pathophysiologic drama: enactment of the trinity of normoxia, hypoxia, and hyperoxia in disease and therapy.

PubMed

Kulkarni, Aditi C; Kuppusamy, Periannan; Parinandi, Narasimham

2007-10-01

Aerobic life has evolved a dependence on molecular oxygen for its mere survival. Mitochondrial oxidative phosphorylation absolutely requires oxygen to generate the currency of energy in aerobes. The physiologic homeostasis of these organisms is strictly maintained by optimal cellular and tissue-oxygenation status through complex oxygen-sensing mechanisms, signaling cascades, and transport processes. In the event of fluctuating oxygen levels leading to either an increase (hyperoxia) or decrease (hypoxia) in cellular oxygen, the organism faces a crisis involving depletion of energy reserves, altered cell-signaling cascades, oxidative reactions/events, and cell death or tissue damage. Molecular oxygen is activated by both nonenzymatic and enzymatic mechanisms into highly reactive oxygen species (ROS). Aerobes have evolved effective antioxidant defenses to counteract the reactivity of ROS. Although the ROS are also required for many normal physiologic functions of the aerobes, overwhelming production of ROS coupled with their insufficient scavenging by endogenous antioxidants will lead to detrimental oxidative stress. Needless to say, molecular oxygen is at the center of oxygenation, oxidative phosphorylation, and oxidative stress. This review focuses on the biology and pathophysiology of oxygen, with an emphasis on transport, sensing, and activation of oxygen, oxidative phosphorylation, oxygenation, oxidative stress, and oxygen therapy.

A negative feedback control of transforming growth factor-beta signaling by glycogen synthase kinase 3-mediated Smad3 linker phosphorylation at Ser-204.

PubMed

Millet, Caroline; Yamashita, Motozo; Heller, Mary; Yu, Li-Rong; Veenstra, Timothy D; Zhang, Ying E

2009-07-24

Through the action of its membrane-bound type I receptor, transforming growth factor-beta (TGF-beta) elicits a wide range of cellular responses that regulate cell proliferation, differentiation, and apo ptosis. Many of these signaling responses are mediated by Smad proteins. As such, controlling Smad activity is crucial for proper signaling by TGF-beta and its related factors. Here, we show that TGF-beta induces phosphorylation at three sites in the Smad3 linker region in addition to the two C-terminal residues, and glycogen synthase kinase 3 is responsible for phosphorylation at one of these sites, namely Ser-204. Alanine substitution at Ser-204 and/or the neighboring Ser-208, the priming site for glycogen synthase kinase 3 in vivo activity, strengthened the affinity of Smad3 to CREB-binding protein, suggesting that linker phosphorylation may be part of a negative feedback loop that modulates Smad3 transcriptional activity. Thus, our findings reveal a novel aspect of the Smad3 signaling mechanism that controls the final amplitude of cellular responses to TGF-beta.

Decreased Phosphorylated Protein Kinase B (Akt) in Individuals with Autism Associated with High Epidermal Growth Factor Receptor (EGFR) and Low Gamma-Aminobutyric Acid (GABA).

PubMed

Russo, Anthony J

2015-01-01

Dysregulation of the PI3K/AKT/mammalian target of rapamycin (mTOR) pathway could contribute to the pathogenesis of autism spectrum disorders. In this study, phosphorylated Akt concentration was measured in 37 autistic children and 12, gender and age similar neurotypical, controls using an enzyme-linked immunosorbent assay. Akt levels were compared to biomarkers known to be associated with epidermal growth factor receptor (EGFR) and c-Met (hepatocyte growth factor (HGF) receptor) pathways and severity levels of 19 autism-related symptoms. We found phosphorylated Akt levels significantly lower in autistic children and low Akt levels correlated with high EGFR and HGF and low gamma-aminobutyric acid, but not other biomarkers. Low Akt levels also correlated significantly with increased severity of receptive language, conversational language, hypotonia, rocking and pacing, and stimming, These results suggest a relationship between decreased phosphorylated Akt and selected symptom severity in autistic children and support the suggestion that the AKT pathways may be associated with the etiology of autism.

Phosphorylation and activation of ubiquitin-specific protease-14 by Akt regulates the ubiquitin-proteasome system

PubMed Central

Xu, Daichao; Shan, Bing; Lee, Byung-Hoon; Zhu, Kezhou; Zhang, Tao; Sun, Huawang; Liu, Min; Shi, Linyu; Liang, Wei; Qian, Lihui; Xiao, Juan; Wang, Lili; Pan, Lifeng; Finley, Daniel; Yuan, Junying

2015-01-01

Regulation of ubiquitin-proteasome system (UPS), which controls the turnover of short-lived proteins in eukaryotic cells, is critical in maintaining cellular proteostasis. Here we show that USP14, a major deubiquitinating enzyme that regulates the UPS, is a substrate of Akt, a serine/threonine-specific protein kinase critical in mediating intracellular signaling transducer for growth factors. We report that Akt-mediated phosphorylation of USP14 at Ser432, which normally blocks its catalytic site in the inactive conformation, activates its deubiquitinating activity in vitro and in cells. We also demonstrate that phosphorylation of USP14 is critical for Akt to regulate proteasome activity and consequently global protein degradation. Since Akt can be activated by a wide range of growth factors and is under negative control by phosphoinosotide phosphatase PTEN, we suggest that regulation of UPS by Akt-mediated phosphorylation of USP14 may provide a common mechanism for growth factors to control global proteostasis and for promoting tumorigenesis in PTEN-negative cancer cells. DOI: http://dx.doi.org/10.7554/eLife.10510.001 PMID:26523394

Phosphorylated Protein Kinase C (Zeta/Lambda) Expression in Colorectal Adenocarcinoma and Its Correlation with Clinicopathologic Characteristics and Prognosis.

PubMed

Yeo, Min-Kyung; Kim, Ji Yeon; Seong, In-Ock; Kim, Jin-Man; Kim, Kyung-Hee

2017-01-01

Background: Protein kinase C zeta/lambda (PKCζ/λ) is a family of protein kinase enzymes that contributes to cell proliferation and regulation, which are important for cancer development. PKCζ/λ has been shown to be an important regulator of tumorigenesis in intestinal cancer. The phosphorylated form of PKCζ/λ, p-PKCζ/λ, is suggested as an active form of PKCζ/λ. However, p-PKCζ/λ expression and its clinicopathologic implication in colorectal adenocarcinoma (CRAC) are unclear. Methods: Seven whole-tissue sections of malignant polyps containing both non-neoplastic and neoplastic mucosa, 11 adenomas with low-grade dysplasia, and 173 CRACs were examined by immunohistochemistry and western blot assay for p-PKCζ/λ protein expression. The association of p-PKCζ/λ expression with clinicopathologic factors including patient survival was studied. Results: In non-neoplastic epithelia, p-PKCζ/λ showed a weak cytoplasmic immunostaining. Adenomas and CRACs demonstrated up-regulated p-PKCζ/λ detection. Cytoplasmic p-PKCζ/λ expression was higher in CRAC than in adenoma. In CRACs, p-PKCζ/λ expression was inversely correlated with pathologic TNM stage (I-II versus III-IV) and poor differentiation. Statistical correlations between low expression of p-PKCζ/λ with shortened overall survival and disease-free survival were seen (p=0.004 and p=0.034, respectively). Conclusions: P-PKCζ/λ overexpression is implicated in tumorigenesis but down-regulation was a poor prognostic factor in CRAC.

Neural stem cells promote nerve regeneration through IL12-induced Schwann cell differentiation.

PubMed

Lee, Don-Ching; Chen, Jong-Hang; Hsu, Tai-Yu; Chang, Li-Hsun; Chang, Hsu; Chi, Ya-Hui; Chiu, Ing-Ming

2017-03-01

Regeneration of injured peripheral nerves is a slow, complicated process that could be improved by implantation of neural stem cells (NSCs) or nerve conduit. Implantation of NSCs along with conduits promotes the regeneration of damaged nerve, likely because (i) conduit supports and guides axonal growth from one nerve stump to the other, while preventing fibrous tissue ingrowth and retaining neurotrophic factors; and (ii) implanted NSCs differentiate into Schwann cells and maintain a growth factor enriched microenvironment, which promotes nerve regeneration. In this study, we identified IL12p80 (homodimer of IL12p40) in the cell extracts of implanted nerve conduit combined with NSCs by using protein antibody array and Western blotting. Levels of IL12p80 in these conduits are 1.6-fold higher than those in conduits without NSCs. In the sciatic nerve injury mouse model, implantation of NSCs combined with nerve conduit and IL12p80 improves motor recovery and increases the diameter up to 4.5-fold, at the medial site of the regenerated nerve. In vitro study further revealed that IL12p80 stimulates the Schwann cell differentiation of mouse NSCs through the phosphorylation of signal transducer and activator of transcription 3 (Stat3). These results suggest that IL12p80 can trigger Schwann cell differentiation of mouse NSCs through Stat3 phosphorylation and enhance the functional recovery and the diameter of regenerated nerves in a mouse sciatic nerve injury model. Copyright © 2016 Elsevier Inc. All rights reserved.

NFκB-Induced Periostin Activates Integrin-β3 Signaling to Promote Renal Injury in GN

PubMed Central

Prakoura, Niki; Kavvadas, Panagiotis; Kormann, Raphaёl; Dussaule, Jean-Claude; Chadjichristos, Christos E.

2017-01-01

De novo expression in the kidney of periostin, a protein involved in odontogenesis and osteogenesis, has been suggested as a biomarker of renal disease. In this study, we investigated the mechanism(s) of induction and the role of periostin in renal disease. Using a combination of bioinformatics, reporter assay, and chromatin immunoprecipitation analyses, we found that NFκB and other proinflammatory transcription factors induce periostin expression in vitro and that binding of these factors on the periostin promoter is enriched in glomeruli during experimental GN. Mice lacking expression of periostin displayed preserved renal function and structure during GN. Furthermore, delayed administration of periostin antisense oligonucleotides in wild-type animals with GN reversed already established proteinuria, diminished tissue inflammation, and improved renal structure. Lack of periostin expression also blunted the de novo renal expression of integrin-β3 and phosphorylation of focal adhesion kinase and AKT, known mediators of integrin-β3 signaling that affect cell motility and survival, observed during GN in wild-type animals. In vitro, recombinant periostin increased the expression of integrin-β3 and the concomitant phosphorylation of focal adhesion kinase and AKT in podocytes. Notably, periostin and integrin-β3 were highly colocalized in biopsy specimens from patients with inflammatory GN. These results demonstrate that interplay between periostin and renal inflammation orchestrates inflammatory and fibrotic responses, driving podocyte damage through downstream activation of integrin-β3 signaling. Targeting periostin may be a novel therapeutic strategy for treating CKD. PMID:27920156

Plasminogen activator inhibitor-1 is an independent prognostic factor of ovarian cancer and IMD-4482, a novel plasminogen activator inhibitor-1 inhibitor, inhibits ovarian cancer peritoneal dissemination.

PubMed

Nakatsuka, Erika; Sawada, Kenjiro; Nakamura, Koji; Yoshimura, Akihito; Kinose, Yasuto; Kodama, Michiko; Hashimoto, Kae; Mabuchi, Seiji; Makino, Hiroshi; Morii, Eiichi; Yamaguchi, Yoichi; Yanase, Takeshi; Itai, Akiko; Morishige, Ken-Ichirou; Kimura, Tadashi

2017-10-27

In the present study, the therapeutic potential of targeting plasminogen activator inhibitor-1 (PAI-1) in ovarian cancer was tested. Tissues samples from 154 cases of ovarian carcinoma were immunostained with anti-PAI-1 antibody, and the prognostic value was analyzed. Among the samples, 67% (104/154) showed strong PAI-1 expression; this was significantly associated with poor prognosis (progression-free survival: 20 vs. 31 months, P = 0.0033). In particular, among patients with stage II-IV serous adenocarcinoma, PAI-1 expression was an independent prognostic factor. The effect of a novel PAI-1 inhibitor, IMD-4482, on ovarian cancer cell lines was assessed and its therapeutic potential was examined using a xenograft mouse model of ovarian cancer. IMD-4482 inhibited in vitro cell adhesion to vitronectin in PAI-1-positive ovarian cancer cells, followed by the inhibition of extracellular signal-regulated kinase and focal adhesion kinase phosphorylation through dissociation of the PAI-urokinase receptor complex from integrin αVβ3. IMD-4482 caused G0/G1 cell arrest and inhibited the proliferation of PAI-1-positive ovarian cancer cells. In the xenograft model, IMD-4482 significantly inhibited peritoneal dissemination with the reduction of PAI-1 expression and the inhibition of focal adhesion kinase phosphorylation. Collectively, the functional inhibition of PAI-1 significantly inhibited ovarian cancer progression, and targeting PAI-1 may be a potential therapeutic strategy in ovarian cancer.

Plasminogen activator inhibitor-1 is an independent prognostic factor of ovarian cancer and IMD-4482, a novel plasminogen activator inhibitor-1 inhibitor, inhibits ovarian cancer peritoneal dissemination

PubMed Central

Nakatsuka, Erika; Sawada, Kenjiro; Nakamura, Koji; Yoshimura, Akihito; Kinose, Yasuto; Kodama, Michiko; Hashimoto, Kae; Mabuchi, Seiji; Makino, Hiroshi; Morii, Eiichi; Yamaguchi, Yoichi; Yanase, Takeshi; Itai, Akiko; Morishige, Ken-ichirou; Kimura, Tadashi

2017-01-01

In the present study, the therapeutic potential of targeting plasminogen activator inhibitor-1 (PAI-1) in ovarian cancer was tested. Tissues samples from 154 cases of ovarian carcinoma were immunostained with anti-PAI-1 antibody, and the prognostic value was analyzed. Among the samples, 67% (104/154) showed strong PAI-1 expression; this was significantly associated with poor prognosis (progression-free survival: 20 vs. 31 months, P = 0.0033). In particular, among patients with stage II-IV serous adenocarcinoma, PAI-1 expression was an independent prognostic factor. The effect of a novel PAI-1 inhibitor, IMD-4482, on ovarian cancer cell lines was assessed and its therapeutic potential was examined using a xenograft mouse model of ovarian cancer. IMD-4482 inhibited in vitro cell adhesion to vitronectin in PAI-1-positive ovarian cancer cells, followed by the inhibition of extracellular signal-regulated kinase and focal adhesion kinase phosphorylation through dissociation of the PAI-urokinase receptor complex from integrin αVβ3. IMD-4482 caused G0/G1 cell arrest and inhibited the proliferation of PAI-1-positive ovarian cancer cells. In the xenograft model, IMD-4482 significantly inhibited peritoneal dissemination with the reduction of PAI-1 expression and the inhibition of focal adhesion kinase phosphorylation. Collectively, the functional inhibition of PAI-1 significantly inhibited ovarian cancer progression, and targeting PAI-1 may be a potential therapeutic strategy in ovarian cancer. PMID:29163796

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ren, Jinqi; Cook, Aaron A.; Bergmeier, Wolfgang

The dynamic regulation of ERK1 and -2 (ERK1/2) is required for precise signal transduction controlling cell proliferation, differentiation, and survival. However, the underlying mechanisms regulating the activation of ERK1/2 are not completely understood. In this study, we show that phosphorylation of RasGRP2, a guanine nucleotide exchange factor (GEF), inhibits its ability to activate the small GTPase Rap1 that ultimately leads to decreased activation of ERK1/2 in cells. ERK2 phosphorylates RasGRP2 at Ser394 located in the linker region implicated in its autoinhibition. These studies identify RasGRP2 as a novel substrate of ERK1/2 and define a negative-feedback loop that regulates the BRaf–MEK–ERKmore » signaling cascade. This negative-feedback loop determines the amplitude and duration of active ERK1/2. -- Highlights: •ERK2 phosphorylates the guanine nucleotide exchange factor RasGRP2 at Ser394. •Phosphorylated RasGRP2 has decreased capacity to active Rap1b in vitro and in cells. •Phosphorylation of RasGRP2 by ERK1/2 introduces a negative-feedback loop into the BRaf-MEK-ERK pathway.« less

PPKs mediate direct signal transfer from phytochrome photoreceptors to transcription factor PIF3

DOE PAGES

Ni, Weimin; Xu, Shou-Ling; González-Grandío, Eduardo; ...

2017-05-11

Upon light-induced nuclear translocation, phytochrome (phy) sensory photoreceptors interact with, and induce rapid phosphorylation and consequent ubiquitin-mediated degradation of, transcription factors, called PIFs, thereby regulating target gene expression and plant development. Nevertheless, the biochemical mechanism of phy-induced PIF phosphorylation has remained ill-defined. Here in this paper we identify a family of nuclear protein kinases, designated Photoregulatory Protein Kinases (PPK1–4; formerly called MUT9-Like Kinases (MLKs)), that interact with PIF3 and phyB in a light-induced manner in vivo. Genetic analyses demonstrate that the PPKs are collectively necessary for the normal light-induced phosphorylation and degradation of PIF3. PPK1 directly phosphorylates PIF3 in vitro,more » with a phosphosite pattern that strongly mimics the light-induced pattern in vivo. These data establish that the PPKs are directly involved in catalysing the photoactivated-phy-induced phosphorylation of PIF3 in vivo, and thereby are critical components of a transcriptionally centred signalling hub that pleiotropically regulates plant growth and development in response to multiple signalling pathways.« less

Thymidine kinase 2 enzyme kinetics elucidate the mechanism of thymidine-induced mitochondrial DNA depletion.

PubMed

Sun, Ren; Wang, Liya

2014-10-07

Mitochondrial thymidine kinase 2 (TK2) is a nuclear gene-encoded protein, synthesized in the cytosol and subsequently translocated into the mitochondrial matrix, where it catalyzes the phosphorylation of thymidine (dT) and deoxycytidine (dC). The kinetics of dT phosphorylation exhibits negative cooperativity, but dC phosphorylation follows hyperbolic Michaelis-Menten kinetics. The two substrates compete with each other in that dT is a competitive inhibitor of dC phosphorylation, while dC acts as a noncompetitive inhibitor of dT phosphorylation. In addition, TK2 is feedback inhibited by dTTP and dCTP. TK2 also phosphorylates a number of pyrimidine nucleoside analogues used in antiviral and anticancer therapy and thus plays an important role in mitochondrial toxicities caused by nucleoside analogues. Deficiency in TK2 activity due to genetic alterations causes devastating mitochondrial diseases, which are characterized by mitochondrial DNA (mtDNA) depletion or multiple deletions in the affected tissues. Severe TK2 deficiency is associated with early-onset fatal mitochondrial DNA depletion syndrome, while less severe deficiencies result in late-onset phenotypes. In this review, studies of the enzyme kinetic behavior of TK2 enzyme variants are used to explain the mechanism of mtDNA depletion caused by TK2 mutations, thymidine overload due to thymidine phosphorylase deficiency, and mitochondrial toxicity caused by antiviral thymidine analogues.

Stimulation of dihydroxyacetone and glycerol kinase activity in Streptococcus faecalis by phosphoenolpyruvate-dependent phosphorylation catalyzed by enzyme I and HPr of the phosphotransferase systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Deutscher, J.; Sauerwald, H.

1986-06-01

Recently a report was given of the phosphoenolpyruvate (PEP)-dependent phosphorylation of a 55-kilodalton protein of Streptococus faecalis catalyzed by enzyme I and histidine-containing protein (HPr) of the phosphotransferase system. The purified 55-kilodalton protein was found to exhibit dihydroxyacetone kinase activity. Glycerol was six times more slowly phosphorylated than dihydroxyacetone. The K/sub m/s were found to 0.7 mM for ATP, 0.45 mM for dihydroxyacetone, and 0.9 MM for glycerol. PEP-dependent phosphorylation of dihydroxyacetone kinase stimulated phosphorylation of both substrates about 10-fold. Fructose 1,6-diphosphate at concentrations higher than 2 mM inhibited the activity of phosphorylated and unphosphorylated dihydroxyacetone kinase in a noncompetitivemore » manner. The rate of PEP-dependent phosphorylation of dihydroxyacetone kinase was about 200-fold slower than the phosphorylation rate of III proteins (also called enzyme III or factor III), which so far have been considered the only phosphoryl acceptors of histidyl-phosphorylated HPr. P-Dihydroxyacetone kinase was found to be able to transfer its phosphoryl group in a backward reaction to HPr. Following (/sup 32/P)PEP-dependent phosphorylation and tryptic digestion of dihydroxyacetone kinase, the authors isolated a labeled peptide composed of 37 amino acids, as determined by amino acid analysis. The single histidyl residue of this peptide most likely carries the phosphoryl group in phosphorylated dihydroxyacetone kinase.« less

Inhibition of Neuroblastoma Tumor Growth by Ketogenic Diet and/or Calorie Restriction in a CD1-Nu Mouse Model.

PubMed

Morscher, Raphael Johannes; Aminzadeh-Gohari, Sepideh; Feichtinger, René Gunther; Mayr, Johannes Adalbert; Lang, Roland; Neureiter, Daniel; Sperl, Wolfgang; Kofler, Barbara

2015-01-01

Neuroblastoma is a malignant pediatric cancer derived from neural crest cells. It is characterized by a generalized reduction of mitochondrial oxidative phosphorylation. The goal of the present study was to investigate the effects of calorie restriction and ketogenic diet on neuroblastoma tumor growth and monitor potential adaptive mechanisms of the cancer's oxidative phosphorylation system. Xenografts were established in CD-1 nude mice by subcutaneous injection of two neuroblastoma cell lines having distinct genetic characteristics and therapeutic sensitivity [SH-SY5Y and SK-N-BE(2)]. Mice were randomized to four treatment groups receiving standard diet, calorie-restricted standard diet, long chain fatty acid based ketogenic diet or calorie-restricted ketogenic diet. Tumor growth, survival, metabolic parameters and weight of the mice were monitored. Cancer tissue was evaluated for diet-induced changes of proliferation indices and multiple oxidative phosphorylation system parameters (respiratory chain enzyme activities, western blot analysis, immunohistochemistry and mitochondrial DNA content). Ketogenic diet and/or calorie restriction significantly reduced tumor growth and prolonged survival in the xenograft model. Neuroblastoma growth reduction correlated with decreased blood glucose concentrations and was characterized by a significant decrease in Ki-67 and phospho-histone H3 levels in the diet groups with low tumor growth. As in human tumor tissue, neuroblastoma xenografts showed distinctly low mitochondrial complex II activity in combination with a generalized low level of mitochondrial oxidative phosphorylation, validating the tumor model. Neuroblastoma showed no ability to adapt its mitochondrial oxidative phosphorylation activity to the change in nutrient supply induced by dietary intervention. Our data suggest that targeting the metabolic characteristics of neuroblastoma could open a new front in supporting standard therapy regimens. Therefore, we propose that a ketogenic diet and/or calorie restriction should be further evaluated as a possible adjuvant therapy for patients undergoing treatment for neuroblastoma.

Methionine supply alters mammary gland antioxidant gene networks via phosphorylation of nuclear factor erythroid 2-like 2 (NFE2L2) protein in dairy cows during the periparturient period.

PubMed

Han, L; Batistel, F; Ma, Y; Alharthi, A S M; Parys, C; Loor, J J

2018-06-13

The periparturient period is the most critical period during the lactation cycle of dairy cows and is characterized by increased oxidative stress status. The objective of this experiment was to evaluate the effect of supplementing rumen-protected methionine on nuclear factor erythroid 2-like 2 (NFE2L2, formerly NRF2) protein and target gene expression in the mammary gland during the early postpartal period. Multiparous Holstein cows were used in a block design experiment with 30 cows per treatment. Treatments consisting of a basal control diet (control) or the basal diet plus rumen-protected methionine (methionine) were fed from d -28 to 60 relative to parturition. Mammary tissue biopsies were harvested on d 21 postpartum from 5 cows per treatment. Compared with control, methionine increased dry matter intake, milk yield, and milk protein content. Among plasma parameters measured, methionine led to greater methionine and lower reactive oxygen metabolites. Compared with control, methionine supply resulted in greater mRNA abundance of the NFE2L2 target genes glutamate-cysteine ligase catalytic subunit (GCLC), glutamate-cysteine ligase modifier subunit (GCLM), glutathione reductase (GSR), glutathione peroxidase 1 (GPX1), malic enzyme 1 (ME1), ferrochelatase (FECH), ferritin heavy chain 1 (FTH1), and NAD(P) H quinone dehydrogenase 1 (NQO1) in the mammary tissue. In addition, methionine upregulated the mRNA abundance of NFE2L2, NFKB1, MAPK14 and downregulated KEAP1. The ratio of phosphorylated NFE2L2 to total NFE2L2 protein, and total heme oxygenase 1 (HMOX1) protein were markedly greater in response to methionine supply. In contrast, total protein abundance of Kelch-like ECH-associated protein 1 (KEAP1), which sequesters NFE2L2 in the cytosol and reduces its activity, was lower with methionine. Besides the consistent positive effect of methionine supply on systemic inflammation and oxidative stress status, the present data indicate a positive effect also on antioxidant mechanisms within the mammary gland, which are regulated, at least in part, via phosphorylation of NFE2L2 and its target genes. The exact mechanisms for these responses merit further study. The Authors. Published by the Federation of Animal Science Societies and Elsevier Inc. on behalf of the American Dairy Science Association®. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/3.0/).

Downregulation of Calcium-Binding Protein S100A9 Inhibits Hypopharyngeal Cancer Cell Proliferation and Invasion Ability Through Inactivation of NF-κB Signaling.

PubMed

Wu, Ping; Quan, Huatao; Kang, Jing; He, Jian; Luo, Shi; Xie, Chubo; Xu, Jing; Tang, Yaoyun; Zhao, Suping

2017-11-02

Hypopharyngeal cancer (HPC) frequently presents at an advanced stage and displays early submucosal spread, resulting in a poor prognosis. It is among the worst of all cancers in the head and neck subsites. Therefore, detection of HPC at an earlier stage would be beneficial to patients. In this study, we used differential in-gel electrophoresis (DIGE) and two-dimensional polyacrylamide gel electrophoresis (2-DE) proteomics analysis to identify the potential biomarkers for HPC. Among the differential proteins identified, calcium-binding protein S100A9 was overexpressed in HPC tissues compared with normal adjacent tissues, and S100A9 expression in metastatic tissues and advanced tumor tissues was higher than in nonmetastatic tissues and early tumor tissues. S100A9 expression was further confirmed in a large additional cohort. Our data showed that a higher S100A9 level was associated with a poor prognosis for HPC patients, and this may be an independent factor for predicting their prognosis. In addition, S100A9 protein expression was upregulated in human HPC cell lines compared with normal oral cavity epithelia. Knockdown of S100A9 induced significant inhibition of cell growth and their invasive ability. Mechanically, we found that downregulation of S100A9 significantly reduced the expression of NF-κB, phosphorylation of NF-κB and Bcl-2, as well as the expression of MMP7 and MMP2. Restoration of NF-κB expression sufficiently reversed the inhibitory effects on cell proliferation and invasion induced by S100A9 downregulation in vitro and in vivo. In conclusion, for the first time, we have identified S100A9 as an independent prognostic factor for HPC. Inhibiting S100A9 expression would be a potential novel diagnostic biomarker and therapeutic target for HPC treatment.

Favorable modulation of benign breast tissue and serum risk biomarkers is associated with > 10 % weight loss in postmenopausal women.

PubMed

Fabian, Carol J; Kimler, Bruce F; Donnelly, Joseph E; Sullivan, Debra K; Klemp, Jennifer R; Petroff, Brian K; Phillips, Teresa A; Metheny, Trina; Aversman, Sonya; Yeh, Hung-Wen; Zalles, Carola M; Mills, Gordon B; Hursting, Stephen D

2013-11-01

We conducted a phase II feasibility study of a 6-month behavioral weight loss intervention in postmenopausal overweight and obese women at increased risk for breast cancer and the effects of weight loss on anthropomorphic, blood, and benign breast tissue biomarkers. 67 women were screened by random peri-areolar fine-needle aspiration, 27 were registered and 24 participated in the interventional phase. The 24 biomarker evaluable women had a median baseline BMI of 34.2 kg/m(2) and lost a median of 11 % of their initial weight. Significant tissue biomarker modulation after the 6-month intervention was noted for Ki-67 (if restricted to the 15 women with any Ki-67 at baseline, p = 0.041), adiponectin to leptin ratio (p = 0.003); and cyclin B1 (p = 0.001), phosphorylated retinoblastoma (p = 0.005), and ribosomal S6 (p = 0.004) proteins. Favorable modulation for serum markers was observed for sex hormone-binding globulin (p < 0.001), bioavailable estradiol (p < 0.001), bioavailable testosterone (p = 0.033), insulin (p = 0.018), adiponectin (p = 0.001), leptin (p < 0.001), the adiponectin to leptin ratio (p < 0.001), C-reactive protein (p = 0.002), and hepatocyte growth factor (p = 0.011). When subdivided by <10 or >10 % weight loss, change in percent total body and android (visceral) fat, physical activity, and the majority of the serum and tissue biomarkers were significantly modulated only for women with >10 % weight loss from baseline. Some factors such as serum PAI-1 and breast tissue pS2 (estrogen-inducible gene) mRNA were not significantly modulated overall but were when considering only those with >10 % weight loss. In conclusion, a median weight loss of 11 % over 6 months resulted in favorable modulation of a number of anthropomorphic, breast tissue and serum risk and mechanistic markers. Weight loss of 10 % or more should likely be the goal for breast cancer risk reduction studies in obese women.

Irisin inhibits hepatic gluconeogenesis and increases glycogen synthesis via the PI3K/Akt pathway in type 2 diabetic mice and hepatocytes.

PubMed

Liu, Tong-Yan; Shi, Chang-Xiang; Gao, Run; Sun, Hai-Jian; Xiong, Xiao-Qing; Ding, Lei; Chen, Qi; Li, Yue-Hua; Wang, Jue-Jin; Kang, Yu-Ming; Zhu, Guo-Qing

2015-11-01

Increased glucose production and reduced hepatic glycogen storage contribute to metabolic abnormalities in diabetes. Irisin, a newly identified myokine, induces the browning of white adipose tissue, but its effects on gluconeogenesis and glycogenesis are unknown. In the present study, we investigated the effects and underlying mechanisms of irisin on gluconeogenesis and glycogenesis in hepatocytes with insulin resistance, and its therapeutic role in type 2 diabetic mice. Insulin resistance was induced by glucosamine (GlcN) or palmitate in human hepatocellular carcinoma (HepG2) cells and mouse primary hepatocytes. Type 2 diabetes was induced by streptozotocin/high-fat diet (STZ/HFD) in mice. In HepG2 cells, irisin ameliorated the GlcN-induced increases in glucose production, phosphoenolpyruvate carboxykinase (PEPCK) and glucose-6-phosphatase (G6Pase) expression, and glycogen synthase (GS) phosphorylation; it prevented GlcN-induced decreases in glycogen content and the phosphoinositide 3-kinase (PI3K) p110α subunit level, and the phosphorylation of Akt/protein kinase B, forkhead box transcription factor O1 (FOXO1) and glycogen synthase kinase-3 (GSK3). These effects of irisin were abolished by the inhibition of PI3K or Akt. The effects of irisin were confirmed in mouse primary hepatocytes with GlcN-induced insulin resistance and in human HepG2 cells with palmitate-induced insulin resistance. In diabetic mice, persistent subcutaneous perfusion of irisin improved the insulin sensitivity, reduced fasting blood glucose, increased GSK3 and Akt phosphorylation, glycogen content and irisin level, and suppressed GS phosphorylation and PEPCK and G6Pase expression in the liver. Irisin improves glucose homoeostasis by reducing gluconeogenesis via PI3K/Akt/FOXO1-mediated PEPCK and G6Pase down-regulation and increasing glycogenesis via PI3K/Akt/GSK3-mediated GS activation. Irisin may be regarded as a novel therapeutic strategy for insulin resistance and type 2 diabetes. © 2015 Authors; published by Portland Press Limited.

A novel EGFR-TKI inhibitor (cAMP-H3BO3complex) combined with thermal therapy is a promising strategy to improve lung cancer treatment outcomes

PubMed Central

Tong, Yongpeng; Huang, Chunliu; Zhang, Junfang

2017-01-01

Purpose Although EGFR-TKIs (epidermal growth factor receptor tyrosine kinase inhibitors) induce favorable responses as first-line non-small cell lung cancer treatments, drug resistance remains a serious problem. Meanwhile, thermal therapy also shows promise as a cancer therapy strategy. Here we combine a novel EGFR-TKI treatment with thermal therapy to improve lung cancer treatment outcomes. Results The results suggest that the cAMP-H3BO3 complex effectively inhibits EGFR auto-phosphorylation, while inducing apoptosis and cell cycle arrest in vitro. Compared to the negative control, tumor growth was significantly suppressed in mice treated with oxidative phosphorylation uncoupler thyroxine sodium and either cAMP-H3BO3 complex or cAMP-H3BO3 complex (P < 0.05). Moreover, the body temperature increase induced by treatment with thyroxine sodium inhibited tumor growth. Immunohistochemical analyses showed that A549 cell apoptosis was significantly higher in the cAMP-H3BO3 complex plus thyroxine sodium treatment group than in the other groups. Moreover,Ca2+ content analysis showed that the Ca2+ content of tumor tissue was significantly higher in the cAMP-H3BO3 complex plus thyroxine sodium treatment group than in other groups. Materials and Methods Inhibition of EGFR auto-phosphorylation by cAMP and cAMP-H3BO3 complex was studied using autoradiography and western blot. The antitumor activity of the novel EGFR inhibitor (cAMP-H3BO3 complex) with or without an oxidative phosphorylation uncoupler (thyroxine sodium) was investigated in vitro and in a nude mouse xenograft lung cancer model incorporating human A549 cells. Conclusions cAMP-H3BO3 complex is a novel EGFR-TKI. Combination therapy using cAMP-H3BO3 with thyroxine sodium-induced thermal therapy may improve lung cancer treatment outcomes. PMID:28915593

PKA regulates calcineurin function through the phosphorylation of RCAN1: Identification of a novel phosphorylation site

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kim, Seon Sook; Lee, Eun Hye; Lee, Kooyeon

2015-04-17

Calcineurin is a calcium/calmodulin-dependent phosphatase that has been implicated in T cell activation through the induction of nuclear factors of activated T cells (NFAT). We have previously suggested that endogenous regulator of calcineurin (RCAN1, also known as DSCR1) is targeted by protein kinase A (PKA) for the control of calcineurin activity. In the present study, we characterized the PKA-mediated phosphorylation site in RCAN1 by mass spectrometric analysis and revealed that PKA directly phosphorylated RCAN1 at the Ser 93. PKA-induced phosphorylation and the increase in the half-life of the RCAN1 protein were prevented by the substitution of Ser 93 with Alamore » (S93A). Furthermore, the PKA-mediated phosphorylation of RCAN1 at Ser 93 potentiated the inhibition of calcineurin-dependent pro-inflammatory cytokine gene expression by RCAN1. Our results suggest the presence of a novel phosphorylation site in RCAN1 and that its phosphorylation influences calcineurin-dependent inflammatory target gene expression. - Highlights: • We identify novel phosphorylation sites in RCAN1 by LC-MS/MS analysis. • PKA-dependent phosphorylation of RCAN1 at Ser 93 inhibits calcineurin-mediated intracellular signaling. • We show the immunosuppressive function of RCAN1 phosphorylation at Ser 93 in suppressing cytokine expression.« less

Myosin dephosphorylation during rapid relaxation of hog carotid artery smooth muscle.

PubMed

Driska, S P; Stein, P G; Porter, R

1989-02-01

Changes in myosin light chain phosphorylation were measured during histamine-induced rhythmic contractions of hog carotid artery smooth muscle strips. Histamine made the muscle strips contract spontaneously every 1-5 min, and this allowed measurement of the time course of phosphorylation in relation to force development under conditions where diffusion of the agonist through tissue would not complicate the interpretation of the data. In the absence of histamine, phosphorylation was low [0.12 +/- 0.04 mol P/mol of the 20,000-Da light chain (LC 20)]. Phosphorylation was slightly (but not significantly) higher in the presence of 10 microM histamine in the relaxed state between contractions (0.20 +/- 0.03 mol P/mol LC 20). In muscle strips frozen during force development, when force had reached half of its peak value, phosphorylation was 0.38 +/- 0.06 mol P/mol LC 20. The highest levels of phosphorylation (0.49 +/- 0.04 mol P/mol LC 20) were found in strips frozen at the peak of the rhythmic contractions. Strips frozen when force had declined to half of the peak force showed low levels of phosphorylation (0.17 +/- 0.07 mol P/mol LC 20), indicating that the myosin light chain phosphatase activity was quite high. Mathematical modeling of the kinase and phosphatase reactions suggested that the apparent first-order phosphatase rate constant was at least 0.08 s-1 under these conditions. To obtain a better estimate of this rate constant, a second series of phosphorylation measurements were made early in the relaxation phase of the rhythmic contractions. The highest phosphatase rate constant obtained from these measurements was 0.23 s-1.(ABSTRACT TRUNCATED AT 250 WORDS)

Phosphorylation of SPT5 by CDKD;2 Is Required for VIP5 Recruitment and Normal Flowering in Arabidopsis thaliana[OPEN

PubMed Central

Lu, Chengyuan; Tian, Yongke; Wang, Shiliang; Su, Yanhua; Mao, Ting; Chen, Qingqing; Xu, Zuntao

2017-01-01

The elongation factor suppressor of Ty 5 homolog (Spt5) is a regulator of transcription and histone methylation. In humans, phosphorylation of SPT5 by P-TEFb, a protein kinase composed of Cyclin-dependent kinase 9 (CDK9) and cyclin T, interacts with the RNA polymerase II-associated factor1 (PAF1) complex. However, the mechanism of SPT5 phosphorylation is not well understood in plants. Here, we examine the function of SPT5 in Arabidopsis thaliana and find that spt5 mutant flowers early under long-day and short-day conditions. SPT5 interacts with the CDK-activating kinase 4 (CAK4; CDKD;2) and is specifically phosphorylated by CDKD;2 at threonines. The phosphorylated SPT5 binds VERNALIZATION INDEPENDENCE5 (VIP5), a subunit of the PAF1 complex. Genetic analysis showed that VIP5 acts downstream of SPT5 and CDKD;2. Loss of SPT5 or CDKD;2 function results in early flowering because of decreased amounts of FLOWERING LOCUS C (FLC) transcript. Importantly, CDKD;2 and SPT5 are required for the deposition of VIP5 and the enhancement of trimethylation of histone 3 lysine 4 in the chromatin of the FLC locus. Together, our results provide insight into the mechanism by which the Arabidopsis elongation factor SPT5 recruits the PAF1 complex via the posttranslational modification of proteins and suggest that the phosphorylation of SPT5 by CDKD;2 enables it to recruit VIP5 to regulate chromatin and transcription in Arabidopsis. PMID:28188267