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1

Increased tyrosine phosphorylation of the insulin receptor, the insulin receptor substrate-1 and a 73 kDa protein associated with insulin-induced mitogenesis in SV40-transformed 3T3T cells  

Microsoft Academic Search

Insulin selectively induces mitogenesis in quiescent SV40 large T antigen-transformed murine 3T3T (CSV3-1) cells but not in quiescent nontransformed 3T3T cells. This mitogenic effect induced by insulin in CSV3-1 cells requires an induction of AP-1 activity associated with c-Jun and JunB. To further investigate the mechanisms that are involved in insulin-induced mitogenesis in CSV3-1 cells, the current experiments were performed.

Hanlin Wang

1999-01-01

2

Depletion of the p43 Mitochondrial T3 Receptor Increases Sertoli Cell Proliferation in Mice  

PubMed Central

Among T3 receptors, TR?1 is ubiquitous and its deletion or a specific expression of a dominant-negative TR?1 isoform in Sertoli cell leads to an increase in testis weight and sperm production. The identification of a 43-kDa truncated form of the nuclear receptor TR?1 (p43) in the mitochondrial matrix led us to test the hypothesis that this mitochondrial transcription factor could regulate Sertoli cell proliferation. Here we report that p43 depletion in mice increases testis weight and sperm reserve. In addition, we found that p43 deletion increases Sertoli cell proliferation in postnatal testis at 3 days of development. Electron microscopy studies evidence an alteration of mitochondrial morphology observed specifically in Sertoli cells of p43?/? mice. Moreover, gene expression studies indicate that the lack of p43 in testis induced an alteration of the mitochondrial-nuclear cross-talk. In particular, the up-regulation of Cdk4 and c-myc pathway in p43?/? probably explain the extended proliferation recorded in Sertoli cells of these mice. Our finding suggests that T3 limits post-natal Sertoli cell proliferation mainly through its mitochondrial T3 receptor p43. PMID:24040148

Fumel, Betty; Roy, Stephanie; Fouchecourt, Sophie; Livera, Gabriel; Parent, Anne-Simone; Casas, Francois; Guillou, Florian

2013-01-01

3

The 230 kDa mature form of KDR\\/Flk-1 (VEGF receptor-2) activates the PLC-? pathway and partially induces mitotic signals in NIH3T3 fibroblasts  

Microsoft Academic Search

KDR\\/Flk-1 tyrosine kinase, one of the two receptors for Vascular Endothelial Growth Factor (VEGF) has been shown to generate the major part of mitotic signals in endothelial cells, although the mechanisms are poorly understood. Here we examined the processing and signal transduction of KDR\\/Flk-1. Both in endothelial cells and in NIH3T3 cells expressing KDR\\/Flk-1, an immature form of KDR\\/Flk-1 with

Tomoko Takahashi; Masabumi Shibuya

1997-01-01

4

6-gingerol inhibits rosiglitazone-induced adipogenesis in 3T3-L1 adipocytes.  

PubMed

We investigated the effects of 6-gingerol ((S)-5-hydroxy-1-(4-hydroxy-3-methoxyphenyl)-3-decanone) on the inhibition of rosiglitazone (RGZ)-induced adipogenesis in 3T3-L1 cells. The morphological changes were photographed based on staining lipid accumulation by Oil-Red O in RGZ (1 µmol/l)-treated 3T3-L1 cells without or with various concentrations of 6-gingerol on differentiation day 8. Quantitation of triglycerides content was performed in cells on day 8 after differentiation induction. Differentiated cells were lysed to detect mRNA and protein levels of adipocyte-specific transcription factors by real-time reverse transcription-polymerase chain reaction and Western blot analysis, respectively. 6-gingerol (50 µmol/l) effectively suppressed oil droplet accumulation and reduced the sizes of the droplets in RGZ-induced adipocyte differentiation in 3T3-L1 cells. The triglyceride accumulation induced by RGZ in differentiated 3T3-L1 cells was also reduced by 6-gingerol (50 µmol/l). Treatment of differentiated 3T3-L1 cells with 6-gingerol (50 µmol/l) antagonized RGZ-induced gene expression of peroxisome proliferator-activated receptor (PPAR)? and CCAAT/enhancer-binding protein ?. Additionally, the increased levels of mRNA and protein in adipocyte-specific fatty acid binding protein 4 and fatty acid synthase induced by RGZ in 3T3-L1 cells were decreased upon treatment with 6-gingerol. Our data suggests that 6-gingerol may be beneficial in obesity, by reducing adipogenesis partly through the down-regulating PPAR? activity. PMID:23519881

Tzeng, Thing-Fong; Chang, Chia Ju; Liu, I-Min

2014-02-01

5

Physiological regulation of hypothalamic TRH transcription in vivo is T 3 receptor isoform specific  

E-print Network

T3) exerts transcriptional effects on target genes in responsive cells. These effects are determined by DNA/protein interactions governed by the type of T3 receptors (TRs) in the cell. As TRs show tissue and developmental variations, regulation is best addressed in an integrated in vivo model. We examined TR subtype effects on thyrotropin-releasing hormone (TRH) transcription and on the pituitary/thyroid axis end point: thyroid hormone secretion. Polyethylenimine served to transfect a TRH-luciferase construct containing 554 bp of the rat TRH promoter into the hypothalami of newborn mice. Transcription from the TRH promoter was regulated in a physiologically faithful manner, being significantly increased in hypothyroidism and decreased in T3treated animals. Moreover, when various ligand binding forms of mouse or chicken TRb and TRa were expressed with TRH-luciferase, all forms of TRb gave T3-dependent regulation of TRH transcription, whereas transcription was T3 insensitive with each TRa tested. Moreover, chicken TRa increased TRH transcription sixfold, whereas mouse TRa decreased transcription. These transcriptional effects had correlated physiological consequences: expression of the chicken TRa in the hypothalamus of newborn mice raised circulating T4 levels by fourfold, whereas mouse TRa had opposite effects. Thus, TR subtypes have distinct, physiologically relevant effects on TRH transcription.—Guissouma, H., Ghorbel, M. T., Seugnet, I., Ouatas, T., Demeneix, B. A. Physiological regulation of hypothalamic TRH transcription in vivo is T3 receptor isoform specific. FASEB J. 12,

Hajer Guissouma; Mohamed T. Ghorbel; Isabelle Seugnet; Taoufik Ouatas; Barbara; A. Demeneix

6

Interaction of human beta 1 thyroid hormone receptor and its mutants with DNA and retinoid X receptor beta. T3 response element-dependent dominant negative potency.  

PubMed Central

Mutations in the human beta thyroid hormone receptor (h-TR beta) gene are associated with the syndrome of generalized resistance to thyroid hormone. We investigated the interaction of three h-TR beta 1 mutants representing different types of functional impairment (kindreds ED, OK, and PV) with different response elements for 3,3',5-triiodothyronine (T3) and with retinoid X receptor beta (RXR beta). The mutant receptors showed an increased tendency to form homodimers on a palindromic T3-response element (TREpal), a direct repeat (DR + 4), and an inverted palindrome (TRElap). On TRElap, wild type TR binding was decreased by T3, while the mutant receptors showed a variably decreased degree of dissociation from TRElap in response to T3. The extent of dissociation was proportional to their T3 binding affinities. RXR beta induced the formation of h-TR beta 1:RXR beta heterodimers equally well for mutants and the wild type h-TR beta 1 on these T3 response elements. However, the T3-dependent increase in heterodimerization with RXR beta was absent or reduced for the mutant TRs. Transient transfection studies indicated that the dominant negative potency was several-fold more pronounced on the TRElap as compared to TREpal or DR + 4. In CV-1 and HeLa cells, transfection of RXR beta could not reverse the dominant negative action. These results demonstrate that the binding of mutant h-TRs to DNA, as well as their dominant negative potency, are TRE dependent. In addition, competition for DNA binding, rather than for limiting amounts of RXR beta, is likely to mediate the dominant negative action. Images PMID:8408652

Meier, C A; Parkison, C; Chen, A; Ashizawa, K; Meier-Heusler, S C; Muchmore, P; Cheng, S Y; Weintraub, B D

1993-01-01

7

Interaction of human beta 1 thyroid hormone receptor and its mutants with DNA and retinoid X receptor beta. T3 response element-dependent dominant negative potency.  

PubMed

Mutations in the human beta thyroid hormone receptor (h-TR beta) gene are associated with the syndrome of generalized resistance to thyroid hormone. We investigated the interaction of three h-TR beta 1 mutants representing different types of functional impairment (kindreds ED, OK, and PV) with different response elements for 3,3',5-triiodothyronine (T3) and with retinoid X receptor beta (RXR beta). The mutant receptors showed an increased tendency to form homodimers on a palindromic T3-response element (TREpal), a direct repeat (DR + 4), and an inverted palindrome (TRElap). On TRElap, wild type TR binding was decreased by T3, while the mutant receptors showed a variably decreased degree of dissociation from TRElap in response to T3. The extent of dissociation was proportional to their T3 binding affinities. RXR beta induced the formation of h-TR beta 1:RXR beta heterodimers equally well for mutants and the wild type h-TR beta 1 on these T3 response elements. However, the T3-dependent increase in heterodimerization with RXR beta was absent or reduced for the mutant TRs. Transient transfection studies indicated that the dominant negative potency was several-fold more pronounced on the TRElap as compared to TREpal or DR + 4. In CV-1 and HeLa cells, transfection of RXR beta could not reverse the dominant negative action. These results demonstrate that the binding of mutant h-TRs to DNA, as well as their dominant negative potency, are TRE dependent. In addition, competition for DNA binding, rather than for limiting amounts of RXR beta, is likely to mediate the dominant negative action. PMID:8408652

Meier, C A; Parkison, C; Chen, A; Ashizawa, K; Meier-Heusler, S C; Muchmore, P; Cheng, S Y; Weintraub, B D

1993-10-01

8

Triac regulation of transcription is T(3) receptor isoform- and response element-specific.  

PubMed

3,5,3'-triiodothyroacetic acid (Triac) is a naturally occurring triiodothyronine (T(3)) analog, which has been used on an empirical basis to treat the syndrome of resistance to thyroid hormone (RTH). The aim of our studies was to compare the effects of Triac and T(3) on negative and positive thyroid hormone response elements (TREs). We used transient transfections with luciferase reporter genes to show that on palindromic, inverted palindrome and human TRH reporters, Triac is more potent than T(3) for transcriptional regulation by TRbeta1 and TRbeta2 isoforms, while regulation by TRalpha1 is equivalent for both ligands. Other TREs (direct repeat, hTSHalpha and hTSHbeta) are not regulated differently by Triac and T(3). Dose-response curves show that the difference between Triac and T(3) is maximal in the 1-10 nM range. Receptor-binding studies reveal a greater affinity of Triac than T(3) for TRbeta1 and TRbeta2 isoforms, which could explain its isoform-specific effects. These data suggest that the TRE- and TR isoform-specific effects of Triac favor its use in RTH. PMID:10940484

Messier, N; Langlois, M F

2000-07-25

9

An angiotensin II AT 1 receptor antagonist, telmisartan augments glucose uptake and GLUT4 protein expression in 3T3-L1 adipocytes  

Microsoft Academic Search

Evidence has accumulated that some of the angiotensin II AT1 receptor antagonists have insulin-sensitizing property. We thus examined the effect of telmisartan on insulin action using 3T3-L1 adipocytes. With standard differentiation inducers, a higher dose of telmisartan effectively facilitated differentiation of 3T3-L1 preadipocytes. Treatment of both differentiating adipocytes and fully differentiated adipocytes with telmisartan caused a dose-dependent increase in mRNA

Muneya Fujimoto; Hiroaki Masuzaki; Tomohiro Tanaka; Shintaro Yasue; Tsutomu Tomita; Kayoko Okazawa; Junji Fujikura; Hideki Chusho; Ken Ebihara; Tatsuya Hayashi; Kiminori Hosoda; Kazuwa Nakao

2004-01-01

10

Withaferin A induces apoptosis and inhibits adipogenesis in 3T3-L1 adipocytes.  

PubMed

Withaferin A (WA), a highly oxygenated steroidal lactone that is found in the medicinal plant Withania somnifera (also called ashwagandha) has been reported to have anti-tumor, anti-angiogenesis, and pro-apoptotic activity. We investigated the effects of WA on viability, apoptosis and adipogenesis in 3T3-L1 adipocytes. Pre- and post-confluent preadipocytes and mature adipocytes were treated with WA (1-25 microM) up to 24 hrs. Viability and apoptosis were measured by CellTiter-Blue Cell Viability Assay and single strand DNA ELISA Assay, respectively. WA decreased viability and induced apoptosis in all stages of cells. Induction of apoptosis by WA in mature adipocytes was mediated by increased ERK1/2 phosphorylation and altered Bax and Bcl2 protein expression. The effect of WA on adipogenesis was examined by AdipoRed Assay after treating with WA (0.1-1 microM) during the differentiation period. WA decreased lipid accumulation in a dose-dependent manner and decreased the expression of peroxisome proliferator-activated receptor gamma, CCAAT/enhancer binding protein alpha and adipocyte fatty acid binding protein. The effects on apoptosis and lipid accumulation were also confirmed with Hoechst staining and Oil Red O staining, respectively. These results show that WA acts on adipocytes to reduce cell viability and adipogenesis and also induce apoptosis. PMID:19346589

Park, Hea Jin; Rayalam, Srujana; Della-Fera, Mary Anne; Ambati, Suresh; Yang, Jeong-Yeh; Baile, Clifton A

2008-01-01

11

Capsaicin Induces "Brite" Phenotype in Differentiating 3T3-L1 Preadipocytes  

PubMed Central

Objective Targeting the energy storing white adipose tissue (WAT) by pharmacological and dietary means in order to promote its conversion to energy expending “brite” cell type holds promise as an anti-obesity approach. Present study was designed to investigate/revisit the effect of capsaicin on adipogenic differentiation with special reference to induction of “brite” phenotype during differentiation of 3T3-L1 preadipocytes. Methods Multiple techniques such as Ca2+ influx assay, Oil Red-O staining, nutrigenomic analysis in preadipocytes and matured adipocytes have been employed to understand the effect of capsaicin at different doses. In addition to in-vitro experiments, in-vivo studies were carried out in high-fat diet (HFD) fed rats treated with resiniferatoxin (RTX) (a TRPV1 agonist) and in mice administered capsaicin. Results TRPV1 channels are expressed in preadipocytes but not in adipocytes. In preadipocytes, both capsaicin and RTX stimulate Ca2+ influx in dose-dependent manner. This stimulation may be prevented by capsazepine, a TRPV1 antagonist. At lower doses, capsaicin inhibits lipid accumulation and stimulates TRPV1 gene expression, while at higher doses it enhances accumulation of lipids and suppresses expression of its receptor. In doses of 0.1–100 µM, capsaicin promotes expression of major pro-adipogenic factor PPAR? and some of its downstream targets. In concentrations of 1 µM, capsaicin up-regulates anti-adipogenic genes. Low-dose capsaicin treatment of 3T3-L1 preadipocytes differentiating into adipocytes results in increased expression of brown fat cell marker genes. In white adipose of mice, capsaicin administration leads to increase in browning-specific genes. Global TRPV1 ablation (i.p. by RTX administration) leads to increase in locomotor activity with no change in body weight. Conclusion Our findings suggest the dual modulatory role of capsaicin in adipogenesis. Capsaicin inhibits adipogenesis in 3T3-L1 via TRPV1 activation and induces brown-like phenotype whereas higher doses. PMID:25072597

Baboota, Ritesh K.; Singh, Dhirendra P.; Sarma, Siddhartha M.; Kaur, Jaspreet; Sandhir, Rajat; Boparai, Ravneet K.; Kondepudi, Kanthi K.; Bishnoi, Mahendra

2014-01-01

12

Folate receptor {alpha} regulates cell proliferation in mouse gonadotroph {alpha}T3-1 cells  

SciTech Connect

We have previously found that the mRNA and protein levels of the folate receptor alpha (FR{alpha}) are uniquely over-expressed in clinically human nonfunctional (NF) pituitary adenomas, but the mechanistic role of FR{alpha} has not fully been determined. We investigated the effect of FR{alpha} over-expression in the mouse gonadotroph {alpha}T3-1 cell line as a model for NF pituitary adenomas. We found that the expression and function of FR{alpha} were strongly up-regulated, by Western blotting and folic acid binding assay. Furthermore, we found a higher cell growth rate, an enhanced percentage of cells in S-phase by BrdU assay, and a higher PCNA staining. These observations indicate that over-expression of FR{alpha} promotes cell proliferation. These effects were abrogated in the same {alpha}T3-1 cells when transfected with a mutant FR{alpha} cDNA that confers a dominant-negative phenotype by inhibiting folic acid binding. Finally, by real-time quantitative PCR, we found that mRNA expression of NOTCH3 was up-regulated in FR{alpha} over-expressing cells. In summary, our data suggests that FR{alpha} regulates pituitary tumor cell proliferation and mechanistically may involve the NOTCH pathway. Potentially, this finding could be exploited to develop new, innovative molecular targeted treatment for human NF pituitary adenomas.

Yao, Congjun; Evans, Chheng-Orn [Department of Neurosurgery and Laboratory of Molecular Neurosurgery and Biotechnology, Emory University, School of Medicine, Atlanta, Georgia (United States)] [Department of Neurosurgery and Laboratory of Molecular Neurosurgery and Biotechnology, Emory University, School of Medicine, Atlanta, Georgia (United States); Stevens, Victoria L. [Epidemiology and Surveillance Research, American Cancer Society, Atlanta, Georgia (United States)] [Epidemiology and Surveillance Research, American Cancer Society, Atlanta, Georgia (United States); Owens, Timothy R. [Emory University, School of Medicine, Atlanta, Georgia (United States)] [Emory University, School of Medicine, Atlanta, Georgia (United States); Oyesiku, Nelson M., E-mail: noyesik@emory.edu [Department of Neurosurgery and Laboratory of Molecular Neurosurgery and Biotechnology, Emory University, School of Medicine, Atlanta, Georgia (United States)

2009-11-01

13

Berberine reverses free-fatty-acid-induced insulin resistance in 3T3-L1 adipocytes through targeting IKK?  

PubMed Central

AIM: To investigate the effects and molecular mechanisms of berberine on improving insulin resistance induced by free fatty acids (FFAs) in 3T3-L1 adipocytes. METHODS: The model of insulin resistance in 3T3-L1 adipocytes was established by adding palmic acid (0.5 mmol/L) to the culture medium. Berberine treatment was performed at the same time. Glucose uptake rate was determined by the 2-deoxy-[3H]-D-glucose method. The levels of IkB kinase beta (IKK?) Ser181 phosphorylation, insulin receptor substrate-1(IRS-1) Ser307 phosphorylation, expression of IKK?, IRS-1, nuclear transcription factor kappaB p65 (NF-?B p65), phosphatidylinositol-3-kinase p85 (PI-3K p85) and glucose transporter 4 (GLUT4) proteins were detected by Western blotting. The distribution of NF-?B p65 proteins inside the adipocytes was observed through confocal laser scanning microscopy (CLSM). RESULTS: After the intervention of palmic acid for 24 h, the insulin-stimulated glucose transport in 3T3-L1 adipocytes was inhibited by 67%. Meanwhile, the expression of IRS-1 and PI-3K p85 protein was reduced, while the levels of IKK? Ser181 and IRS-1 Ser307 phosphorylation, and nuclear translocation of NF-?B p65 protein were increased. However, the above indexes, which indicated the existence of insulin resistance, were reversed by berberine although the expression of GLUT4, IKK? and total NF-?B p65 protein were not changed during this study. CONCLUSION: Insulin resistance induced by FFAs in 3T3-L1 adipocytes can be improved by berberine. Berberine reversed free-fatty-acid-induced insulin resistance in 3T3-L1 adipocytes through targeting IKK?. PMID:18240344

Yi, Ping; Lu, Fu-Er; Xu, Li-Jun; Chen, Guang; Dong, Hui; Wang, Kai-Fu

2008-01-01

14

Mice Lacking the p43 Mitochondrial T3 Receptor Become Glucose Intolerant and Insulin Resistant during Aging  

PubMed Central

Thyroid hormones (TH) play an important regulatory role in energy expenditure regulation and are key regulators of mitochondrial activity. We have previously identified a mitochondrial triiodothyronine (T3) receptor (p43) which acts as a mitochondrial transcription factor of the organelle genome, which leads in vitro and in vivo, to a stimulation of mitochondrial biogenesis. Recently, we generated mice carrying a specific p43 invalidation. At 2 months of age, we reported that p43 depletion in mice induced a major defect in insulin secretion both in vivo and in isolated pancreatic islets, and a loss of glucose-stimulated insulin secretion. The present study was designed to determine whether p43 invalidation influences life expectancy and modulates blood glucose and insulin levels as well as glucose tolerance or insulin sensitivity during aging. We report that from 4 months old onwards, mice lacking p43 are leaner than wild-type mice. p43?/? mice also have a moderate reduction of life expectancy compared to wild type. We found no difference in blood glucose levels, excepted at 24 months old where p43?/? mice showed a strong hyperglycemia in fasting conditions compared to controls animals. However, the loss of glucose-stimulated insulin secretion was maintained whatever the age of mice lacking p43. If up to 12 months old, glucose tolerance remained unchanged, beyond this age p43?/? mice became increasingly glucose intolerant. In addition, if up to 12 months old p43 deficient animals were more sensitive to insulin, after this age we observed a loss of this capacity, culminating in 24 months old mice with a decreased sensitivity to the hormone. In conclusion, we demonstrated that during aging the depletion of the mitochondrial T3 receptor p43 in mice progressively induced an increased glycemia in the fasted state, glucose intolerance and an insulin-resistance several features of type-2 diabetes. PMID:24098680

Bertrand, Christelle; Blanchet, Emilie; Pessemesse, Laurence; Annicotte, Jean Sebastien; Feillet-Coudray, Christine; Chabi, Beatrice; Levin, Jonathan; Fajas, Lluis; Cabello, Gerard; Wrutniak-Cabello, Chantal; Casas, Francois

2013-01-01

15

Targeted inactivation of the insulin receptor gene in mouse 3T3-L1 fibroblasts via homologous recombination.  

PubMed Central

To study the role of the insulin receptor in determining adipocyte differentiation of the mouse cell line 3T3-L1, we have introduced a mutation that inactivates the insulin receptor gene by homologous recombination. In two independent clones, inactivation of one allele of the insulin receptor gene was associated with a 50-70% reduction in the number of insulin receptors. In addition, both clones were markedly impaired in their ability to differentiate into adipocytes. The defect in adipocyte-specific differentiation was corrected by expression of transfected human insulin receptor cDNA. These data suggest that the insulin receptor may play an important role in promoting differentiation of 3T3-L1 cells into adipocytes in vitro. Images PMID:2052553

Accili, D; Taylor, S I

1991-01-01

16

Pear pomace water extract inhibits adipogenesis and induces apoptosis in 3T3-L1 adipocytes  

PubMed Central

Obesity occurs when a person's calorie intake exceeds the amount of energy burns, which may lead to pathologic growth of adipocytes and the accumulation of fat in the tissues. In this study, the effect and mechanism of pear pomace extracts on 3T3-L1 adipocyte differentiation and apoptosis of mature adipocytes were investigated. The effects of pear pomace extract on cell viability and the anti-adipogenic and proapoptotic effects were investigated via MTT assay, Oil red O staining, western blot analysis and apoptosis assay. 3T3-L1 preadipocytes were stimulated with DMEM containing 10% FBS, 0.5 mM 3-isobutyl-1-methylxanthine (IBMX), 5 µg/ml insulin and 1 µM dexamethasone for differentiation to adipocytes. 3T3-L1 cells were cultured with PBS or water extract of pear pomace. Water extract of pear pomace effectively inhibited lipid accumulations and expressions of PPAR-? and C/EBP? in 3T3-L1 cells. It also increased expression of p-AMPK and decreased the expression of SREBP-1c and FAS in 3T3-L1 cells. The induction of apoptosis was observed in 3T3-L1 cells treated with pear pomace. These results indicate that pear pomace water extract inhibits adipogenesis and induces apoptosis of adipocytes and thus can be used as a potential therapeutic substance as part of prevention or treatment strategy for obesity. PMID:24611103

Rhyu, Jin; Kim, Min Sook; You, Mi-Kyoung; Bang, Mi-Ae

2014-01-01

17

Expression of T3 in association with a molecule distinct from the T-cell antigen receptor heterodimer.  

PubMed Central

The T-cell antigen receptor consists of a disulfide-linked heterodimer (Ti) that is associated with another set of three nonpolymorphic, noncovalently linked peptides termed "T3." The cell surface expression of T3 has been thought to depend upon association with Ti. In this study, we demonstrate that T3 can be expressed in the absence of an associated Ti molecule on a T-cell leukemic line, PEER. Instead, on this cell line, T3 appears to be expressed in association with a 55- to 60-kDa glycoprotein that has a peptide backbone of 29 kDa. PEER fails to express Ti alpha-chain transcripts but does express Ti beta- and gamma-chain transcripts. Using a monoclonal antibody that reacts with nonpolymorphic epitopes expressed on Ti, WT31, we demonstrate that PEER fails to react with this antibody but does react with three independently derived anti-T3 antibodies. Moreover, a small subpopulation of T3-positive peripheral blood lymphocytes, like PEER, fails to express the antigenic determinants recognized by WT31. These results suggest that, on these normal lymphocytes, T3 may likewise be associated with a non-Ti molecule. The possibility that the 55- to 60-kDa molecule expressed on PEER, termed "Tp55-60," represents the protein product of the previously identified Ti gamma-chain gene is discussed. Images PMID:3092224

Weiss, A; Newton, M; Crommie, D

1986-01-01

18

Human papillomavirus type 16 DNA-induced malignant transformation of NIH 3T3 cells  

SciTech Connect

A biological function for human papillomavirus 16 (HPV 16) DNA was demonstrated by transformation of NIH 3T3 cells. HPV 16 DNA has been found frequently in genital cancer and has been classified as a papillomavirus on the basis of DNA homology. A recombinant HPV 16 DNA (pSHPV16d), which contains a head-to-tail dimer of the full-length HPV 16 genome, induced morphologic transformation; the transformed cells were tumorigenic in nude mice. Expression of transforming activity was unique because of the long latency period (more than 4 weeks) required for induction of morphologic transformation and because the transfected DNA existed primarily in a multimeric form with some rearrangement. Furthermore, virus-specific RNAs were expressed in the transformants. The transformation of NIH 3T3 cells provides a model for analyzing the functions of HPV 16, which is associated with cervical carcinomas.

Yasumoto, S.; Burkhardt, A.L.; Doniger, J.; DiPaolo, J.A.

1986-02-01

19

Trichostatin A Modulates Thiazolidinedione-Mediated Suppression of Tumor Necrosis Factor ?-Induced Lipolysis in 3T3-L1 Adipocytes  

PubMed Central

In obesity, high levels of tumor necrosis factor ? (TNF?) stimulate lipolysis in adipocytes, leading to hyperlipidemia and insulin resistance. Thiazolidinediones (TZDs), the insulin-sensitizing drugs, antagonize TNF?-induced lipolysis in adipocytes, thereby increasing insulin sensitivity in diabetes patients. The cellular target of TZDs is peroxisome proliferator-activated receptor ? (PPAR?), a nuclear receptor that controls many adipocyte functions. As a transcription factor, PPAR? is closely modulated by coregulators, which include coactivators and corepressors. Previous studies have revealed that in macrophages, the insulin-sensitizing effect of PPAR? may involve suppression of proinflammatory gene expression by recruiting the corepressor complex that contains corepressors and histone deacetylases (HDACs). Therefore, we investigated whether the corepressor complex is involved in TZD-mediated suppression of TNF?-induced lipolysis in 3T3-L1 adipocytes. Trichostatin A (TSA), a pan HDAC inhibitor (HDACI) that inhibits class I and II HDACs, was used to examine the involvement of HDACs in the actions of TZDs. TSA alone increased basal lipolysis and attenuated TZD-mediated suppression of TNF?-induced lipolysis. Increased basal lipolysis may in part result from class I HDAC inhibition because selective class I HDACI treatment had similar results. However, attenuation of TZD-mediated TNF? antagonism may be specific to TSA and related hydroxamate-based HDACI rather than to HDAC inhibition. Consistently, corepressor depletion did not affect TZD-mediated suppression. Interestingly, TSA treatment greatly reduced PPAR? levels in differentiated adipocytes. Finally, extracellular signal-related kinase 1/2 (ERK1/2) mediated TNF?-induced lipolysis, and TZDs suppressed TNF?-induced ERK phosphorylation. We determined that TSA increased basal ERK phosphorylation, and attenuated TZD-mediated suppression of TNF?-induced ERK phosphorylation, consistent with TSA’s effects on lipolysis. These studies suggest that TSA, through down-regulating PPAR?, attenuates TZD-mediated suppression of TNF?-induced ERK phosphorylation and lipolysis in adipocytes. PMID:23951179

Lu, Juu-Chin; Chang, Yu-Tzu; Wang, Chih-Tien; Lin, Yu-Chun; Lin, Chun-Ken; Wu, Zhong-Sheng

2013-01-01

20

Prednisolone induces the Wnt signalling pathway in 3T3-L1 adipocytes  

PubMed Central

Synthetic glucocorticoids are potent anti-inflammatory drugs but show dose-dependent metabolic side effects such as the development of insulin resistance and obesity. The precise mechanisms involved in these glucocorticoid-induced side effects, and especially the participation of adipose tissue in this are not completely understood. We used a combination of transcriptomics, antibody arrays and bioinformatics approaches to characterize prednisolone-induced alterations in gene expression and adipokine secretion, which could underlie metabolic dysfunction in 3T3-L1 adipocytes. Several pathways, including cytokine signalling, Akt signalling, and Wnt signalling were found to be regulated at multiple levels, showing that these processes are targeted by prednisolone. These results suggest that mechanisms by which prednisolone induce insulin resistance include dysregulation of wnt signalling and immune response processes. These pathways may provide interesting targets for the development of improved glucocorticoids. PMID:23506355

Fleuren, Wilco W. M.; Linssen, Margot M. L.; Toonen, Erik J. M.; van der Zon, Gerard C. M.; Guigas, Bruno; de Vlieg, Jacob; Dokter, Wim H. A.; Ouwens, D. Margriet

2013-01-01

21

Localization of transferrin receptors and insulin-like growth factor II receptors in vesicles from 3T3-L1 adipocytes that contain intracellular glucose transporters  

PubMed Central

Transferrin receptors in detergent extracts of subcellular membrane fractions prepared from 3T3-L1 adipocytes were measured by a binding assay. There was a small but significant increase (1.2-fold) in the amount of receptor in a crude plasma membrane fraction and a 40% decrease in the number of transferrin receptors in microsomal membranes prepared from insulin-treated cells, when compared with corresponding fractions from control cells. Intracellular vesicles containing insulin- responsive glucose transporters (GT) have been isolated by immunoadsorption from the microsomal fraction (Biber, J. W., and G. E. Lienhard. 1986. J. Biol. Chem. 261:16180-16184). All of the transferrin receptors in this fraction were localized in these vesicles; however, because the GT vesicles contain approximately 30-fold fewer transferrin receptors than GT, on the average only one vesicle in three contains a transferrin receptor. The binding of 125I-pentamannose 6-phosphate BSA to 3T3-L1 adipocytes at 4 degrees C was used to monitor surface insulin- like growth factor II (IGF-II)/mannose 6-phosphate receptors. Exposure of cells to insulin at 37 degrees C for 5 min resulted in a 2.5-4.5- fold increase in surface receptors. There was a corresponding 20% decrease in the amount of IGF-II receptors in the microsomal membranes prepared from insulin-treated cells, as assayed by immunoblotting. Moreover, the IGF-II receptors and GT were located in the same intracellular vesicles, since antibodies to the carboxyterminal peptide of either protein immunoadsorbed vesicles containing 70-95% of both proteins initially present in the microsomal fraction. In conjunction with other studies, these results indicate that in 3T3-L1 adipocytes, three membrane proteins (the GT, the transferrin receptor, and the IGF- II receptor) respond similarly to insulin, by redistributing to the surface from intracellular compartment(s) in which they are colocalized. PMID:2538483

1989-01-01

22

EGF receptor is involved in WNT3a-mediated proliferation and motility of NIH3T3 cells via ERK pathway activation.  

PubMed

WNT3a stimulates proliferation of NIH3T3 cells via activation of the extracellular signal-regulated kinase (ERK) pathway. The RAF-1-->MEK-->ERK cascade was immediately increased by WNT3a treatment, however, the upstream event triggering ERK pathway activation by WNT3a is not clear. WNT3a activated RAS and WNT3a-induced ERK activation was blocked by dominant-negative RAS, indicating that WNT3a might act upstream of RAS. WNT3a-induced ERK pathway activations were blocked by AG1478, the epidermal growth factor receptor (EGFR) inhibitor, and EGFR siRNA. The WNT3a-induced ERK pathway activation was not observed in fibroblasts retaining defective EGFR, but the WNT3a effect was restored by EGFR reconstitution. These results indicate involvement of EGFR in the WNT3a-induced ERK pathway activation. WNT3a-induced motility and cytoskeletal rearrangement as well as proliferation of NIH3T3 cells were blocked by AG1478 and EGFR siRNA or abolished in EGFR knock-out fibroblasts, indicating involvement of EGFR in those cellular processes. WNT3a-induced ERK pathway activation was not affected by Dickkoff-1 (DKK-1), although WNT3a-induced activations of the WNT/beta-catenin pathway and proliferation were reduced by DKK-1. EGFR is involved in WNT3a-induced proliferation via both routes dependent on and independent of the WNT/beta-catenin pathway. These results indicate that WNT3a stimulates proliferation and motility of NIH3T3 fibroblasts via EGFR-mediated ERK pathway activation. PMID:17374561

Kim, Sung-Eun; Choi, Kang-Yell

2007-07-01

23

Characterization and cloning of a receptor for BMP-2 and BMP-4 from NIH 3T3 cells.  

PubMed Central

The bone morphogenetic proteins (BMPs) are a group of transforming growth factor beta (TGF-beta)-related factors whose only receptor identified to date is the product of the daf-4 gene from Caenorhabditis elegans. Mouse embryonic NIH 3T3 fibroblasts display high-affinity 125I-BMP-4 binding sites. Binding assays are not possible with the isoform 125I-BMP-2 unless the positively charged N-terminal sequence is removed to create a modified BMP-2, 125I-DR-BMP-2. Cross-competition experiments reveal that BMP-2 and BMP-4 interact with the same binding sites. Affinity cross-linking assays show that both BMPs interact with cell surface proteins corresponding in size to the type I (57- to 62-kDa) and type II (75- to 82-kDa) receptor components for TGF-beta and activin. Using a PCR approach, we have cloned a cDNA from NIH 3T3 cells which encodes a novel member of the transmembrane serine/threonine kinase family most closely resembling the cloned type I receptors for TGF-beta and activin. Transient expression of this receptor in COS-7 cells leads to an increase in specific 125I-BMP-4 binding and the appearance of a major affinity-labeled product of approximately 64 kDa that can be labeled by either tracer. This receptor has been named BRK-1 in recognition of its ability to bind BMP-2 and BMP-4 and its receptor kinase structure. Although BRK-1 does not require cotransfection of a type II receptor in order to bind ligand in COS cells, complex formation between BRK-1 and the BMP type II receptor DAF-4 can be demonstrated when the two receptors are coexpressed, affinity labeled, and immunoprecipitated with antibodies to either receptor subunit. We conclude that BRK-1 is a putative BMP type I receptor capable of interacting with a known type II receptor for BMPs. Images PMID:8065329

Koenig, B B; Cook, J S; Wolsing, D H; Ting, J; Tiesman, J P; Correa, P E; Olson, C A; Pecquet, A L; Ventura, F; Grant, R A

1994-01-01

24

The T3R alpha gene encoding a thyroid hormone receptor is essential for post-natal development and thyroid hormone production.  

PubMed Central

The diverse functions of thyroid hormones are thought to be mediated by two nuclear receptors, T3R alpha1 and T3R beta, encoded by the genes T3R alpha and T3R beta respectively. The T3R alpha gene also produces a non-ligand-binding protein T3R alpha2. The in vivo functions of these receptors are still unclear. We describe here the homozygous inactivation of the T3R alpha gene which abrogates the production of both T3R alpha1 and T3R alpha2 isoforms and that leads to death in mice within 5 weeks after birth. After 2 weeks of life, the homozygous mice become progressively hypothyroidic and exhibit a growth arrest. Small intestine and bones showed a strongly delayed maturation. In contrast to the negative regulatory function of the T3R beta gene on thyroid hormone production, our data show that the T3R alpha gene products are involved in up-regulation of thyroid hormone production at weaning time. Thus, thyroid hormone production might be balanced through a positive T3R alpha and a negative T3R beta pathway. The abnormal phenotypes observed on the homozygous mutant mice strongly suggest that the T3R alpha gene is essential for the transformation of a mother-dependent pup to an 'adult' mouse. These data define crucial in vivo functions for thyroid hormones through a T3R alpha pathway during post-natal development. PMID:9250685

Fraichard, A; Chassande, O; Plateroti, M; Roux, J P; Trouillas, J; Dehay, C; Legrand, C; Gauthier, K; Kedinger, M; Malaval, L; Rousset, B; Samarut, J

1997-01-01

25

Lunasin-aspirin combination against NIH/3T3 cells transformation induced by chemical carcinogens.  

PubMed

Carcinogenesis is a multistage process involving a number of molecular pathways sensitive to intervention. Chemoprevention is defined as the use of natural and/or synthetic substances to block, reverse, or retard the process of carcinogenesis. To achieve greater inhibitory effects on cancer cells, combination of two or more chemopreventive agents is commonly considered as a better preventive and/or therapeutic strategy. Lunasin is a promising cancer preventive peptide identified in soybean and other seeds. Its efficacy has been demonstrated by both in vitro and in vivo models. This peptide has been found to inhibit human breast cancer MDA-MB-231 cells proliferation, suppressing cell cycle progress and inducing cell apoptosis. Moreover, lunasin potentiates the effects on these cells of different synthetic and natural compounds, such as aspirin and anacardic acid. This study explored the role of lunasin, alone and in combination with aspirin and anacardic acid on cell proliferation and foci formation of transformed NIH/3T3 cells induced by chemical carcinogens 7,12-dimethylbenz[a]anthracene or 3-methylcholanthrene. The results revealed that lunasin, acting as a single agent, inhibits cell proliferation and foci formation. When combined with aspirin, these effects were significantly increased, indicating that this combination might be a promising strategy to prevent/treat cancer induced by chemical carcinogens. PMID:21562729

Hsieh, Chia-Chien; Hernández-Ledesma, Blanca; de Lumen, Ben O

2011-06-01

26

Malignant Transformation Induced by Incorporated Radionuclides in BALB/3T3 Mouse Embryo Fibroblasts  

NASA Astrophysics Data System (ADS)

The induction of lethality and malignant transformation by 5-[125I]iododeoxyuridine and [3H]thymidine incorporated into cellular DNA and by x-irradiation was studied in vitro in BALB/3T3 cells. Under these conditions, 125I radiation is highly localized to small regions of the DNA at the site of each decay and produces DNA double-strand breaks with high efficiency. Incorporated 125I was found to be 12-16 times as lethal per decay as incorporated 3H. For the induction of malignant transformation, however, 125I was approximately 25 times as effective per decay as 3H. When the frequencies of transformation induced at various levels of survival by 125I, 3H, and x-rays were compared, lethality was found to correlate closely with transformation at doses that yielded significant cell killing. An exception occurred at low doses, where 125I appeared much more efficient than x-irradiation in inducing transformation; transformation frequencies equal to those induced by 3-5 Gy of x-rays resulted from 125I exposures that yielded little or no cell killing.

Lemotte, Peter K.; Adelstein, S. James; Little, John B.

1982-12-01

27

Diacylglycerol treatment rapidly decreases the affinity of the epidermal growth factor receptors of Swiss 3T3 cells.  

PubMed

The synthetic diacylglycerol 1-oleoyl-2-acetyl glycerol (OAG) and phorbol esters activate protein kinase C in intact cells. We report here that OAG inhibits the binding of 125I-labelled epidermal growth factor (125I-EGF) to Swiss 3T3 cells. The inhibition was detected as early as 1 min after treatment at 37 degrees C and persisted for at least 120 min. The effect of OAG was reversed upon removal of this diacylglycerol. Detailed Scatchard analysis of 125I-EGF binding to Swiss 3T3 cells at 4 degrees C after a 1 h incubation with a saturating dose of OAG at 37 degrees C, demonstrates that this OAG pretreatment does not change the apparent number of EGF receptors but causes a marked decrease in their apparent affinity for the ligand. Prolonged treatment (40 h) of the cells with phorbol dibutyrate (PBt2) which causes a marked decrease in the number of phorbol ester binding sites and in the activity of protein kinase C, prevented the inhibition of 125I-EGF binding by both PBt2 and OAG. The results support the possibility that protein kinase C plays a role in the transmodulation of the EGF receptor in intact cells. PMID:2995413

Sinnett-Smith, J W; Rozengurt, E

1985-07-01

28

Lipid Rafts\\/Caveolae Are Essential for Insulin-like Growth Factor1 Receptor Signaling during 3T3-L1 Preadipocyte Differentiation Induction  

Microsoft Academic Search

Lipid rafts\\/caveolae are found to be essential for insu- lin-like growth factor (IGF)-1 receptor signaling during 3T3-L1 preadipocyte differentiation induction. In 3T3-L1 cells, IGF-1 receptor is located in lipid rafts\\/ caveolae of the plasma membrane and can directly in- teract with caveolin-1, the major protein component in caveolae. Disruption of lipid rafts\\/caveolae by depleting cellular cholesterol with cholesterol-binding reagent, -methylcyclodextrin

Hairong Huo; Xuemin Guo; Shangyu Hong; Manrong Jiang; Xinyuan Liu; Kan Liao

2003-01-01

29

Berberine reverses free-fatty-acid-induced insulin resistance in 3T3-L1 adipocytes through targeting IKK?  

Microsoft Academic Search

AIM: To investigate the effects and molecular mechanisms of berberine on improving insulin resistance induced by free fatty acids (FFAs) in 3T3-L1 adipocytes. METHODS: The model of insulin resistance in 3T3-L1 adipocytes was established by adding palmic acid (0.5 mmol\\/L) to the culture medium. Berberine treatment was performed at the same time. Glucose uptake rate was determined by the 2-deoxy-(

Ping Yi; Fu-Er Lu; Li-Jun Xu; Guang Chen; Hui Dong; Kai-Fu Wang

2008-01-01

30

Mouse osteoblastic cell line (MC3T3-E1) expresses extracellular calcium (Ca2+o)-sensing receptor and its agonists stimulate chemotaxis and proliferation of MC3T3-E1 cells  

NASA Technical Reports Server (NTRS)

The calcium-sensing receptor (CaR) is a G protein-coupled receptor that plays key roles in extracellular calcium ion (Ca2+o) homeostasis in parathyroid gland and kidney. Osteoblasts appear at sites of osteoclastic bone resorption during bone remodeling in the "reversal" phase following osteoclastic resorption and preceding bone formation. Bone resorption produces substantial local increases in Ca2+o that could provide a signal for osteoblasts in the vicinity, leading us to determine whether such osteoblasts express the CaR. In this study, we used the mouse osteoblastic, clonal cell line MC3T3-E1. Both immunocytochemistry and Western blot analysis, using an antiserum specific for the CaR, detected CaR protein in MC3T3-E1 cells. We also identified CaR transcripts in MC3T3-E1 cells by Northern analysis using a CaR-specific riboprobe and by reverse transcription-polymerase chain reaction with CaR-specific primers, followed by nucleotide sequencing of the amplified products. Exposure of MC3T3-E1 cells to high Ca2+o (up to 4.8 mM) or the polycationic CaR agonists, neomycin and gadolinium (Gd3+), stimulated both chemotaxis and DNA synthesis in MC3T3-E1 cells. Therefore, taken together, our data strongly suggest that the osteoblastic cell line MC3T3-E1 possesses both CaR protein and mRNA very similar, if not identical, to those in parathyroid and kidney. Furthermore, the CaR in these osteoblasts could play a key role in regulating bone turnover by stimulating the proliferation and migration of such cells to sites of bone resorption as a result of local release of Ca2+o.

Yamaguchi, T.; Chattopadhyay, N.; Kifor, O.; Butters, R. R. Jr; Sugimoto, T.; Brown, E. M.; O'Malley, B. W. (Principal Investigator)

1998-01-01

31

A shift in the ligand responsiveness of thyroid hormone receptor alpha induced by heterodimerization with retinoid X receptor alpha.  

PubMed Central

Thyroid hormone (T3) receptors (T3Rs) are ligand-modulated transcription factors that bind to thyroid hormone response elements (T3REs) and mediate either positive or negative transcriptional regulation of target genes. In addition, in response to ligand binding, T3Rs can interfere with AP-1 activity and thereby inhibit transcription of AP-1-responsive genes. T3Rs were recently shown to form heterodimers with retinoid X receptors (RXRs), leading to increased binding to T3REs in vitro and potentiation of transcriptional responses in vivo. Here we demonstrate that T3R alpha forms stable heterodimers with RXR alpha in living cells. Most important, we describe a new role for RXR alpha in modulating ligand-dependent T3R alpha activity: heterodimerization with RXR alpha greatly increases transcriptional interference with AP-1 activity, augments T3-dependent transcriptional activation, and potentiates the reversal of ligand-independent activation by T3R alpha. In all three cases, the responses occur at substantially lower T3 concentrations when elicited by T3R alpha plus RXR alpha than by T3R alpha alone. In vitro, the binding of T3 decreases the DNA-binding activity of T3R alpha homodimers but does not affect DNA binding by T3R alpha:RXR alpha heterodimers. We provide evidence that increased activities of T3R alpha at lower T3 concentrations are not due to changes in its T3 binding properties. Instead, the altered response could be mediated by either RXR alpha-induced conformational changes, increased stability of heterodimers over homodimers, especially following T3 binding, or both. PMID:8524299

Claret, F X; Antakly, T; Karin, M; Saatcioglu, F

1996-01-01

32

Inducible production of c-fos antisense RNA inhibits 3T3 cell proliferation.  

PubMed Central

Antisense RNA complementary to c-fos mRNA was produced in mouse 3T3 cells by gene transfer techniques. Transcriptional units were constructed consisting of a steroid-inducible mouse mammary tumor virus (MMTV) promoter, mouse or human 5' c-fos gene fragments in either the sense (5' to 3') or antisense (3' to 5') orientation, and splice and poly(A) signals from the human beta-globin gene. A gene that confers neomycin resistance was included in the vectors to allow isolation of stable transformants. Dexamethasone caused a marked induction of hybrid MMTV-fos-globin RNA. Induction of the hybrid transcript containing antisense c-fos RNA decreased colony formation following DNA transfer and inhibited the proliferation of cells into which the antisense transcriptional unit had been integrated. In contrast, colony formation and cell proliferation were not inhibited by induction of hybrid RNA containing c-fos RNA sequences in the sense orientation. These results indicate that the strategy of generating antisense RNA to inhibit gene expression may be useful in delineating the function of protooncogenes. The c-fos gene product appears to have a required role in normal cell division. Images PMID:3523478

Holt, J T; Gopal, T V; Moulton, A D; Nienhuis, A W

1986-01-01

33

Microconstituent-Induced Pitting Corrosion in Aluminum Alloy 2024-T3  

Microsoft Academic Search

Free corrosion immersion experiments were conducted on a commercial airframe material, Al 2024-T3 (UNS A92024), in 0.5 M sodium chloride (NaCl) solution to investigate the role of microconstituents in pitting corrosion. The alloy was found to contain numerous constituent particles (> 300,000 per cm [> 2 million per in.]), and pitting corrosion essentially was attributable to these particles. Two types

G. S. Chen; M. S. Gao; R. P. Wei

1996-01-01

34

Conjugated linoleic acid suppresses triglyceride accumulation and induces apoptosis in 3T3-L1 preadipocytes  

Microsoft Academic Search

Four sets of experiments were conducted to examine the influence of conjugated linoleic acid (CLA) isomers during proliferation\\u000a and differentiation of cultures of 3T3-L1 preadipocytes using physiological culturing conditions. Cultures treated with either\\u000a albumin [bovine serum albumin (BSA) vehicle] or linoleic acid (LA) served as controls. For the proliferation study (Expt.\\u000a 1), cells were cultured in media containing a crude

M. Evans; C. Geigerman; J. Cook; L. Curtis; B. Kuebler; M. McIntosh

2000-01-01

35

Molecular Mechanisms of Apoptosis Induced by Ajoene in 3T3-L1 Adipocytes  

Microsoft Academic Search

Objective: Determine the biochemical pathways involved in induction of apoptosis by ajoene, an organosulfur compound from garlic.Research Methods and Procedures: Mature 3T3-L1 adipocytes were incubated with ajoene at concentrations up to 200 ?M. Viability and apoptosis were quantified using an MTS-based cell viability assay and an enzyme-linked immunosorbent assay for single-stranded DNA (ssDNA), respectively. Intracellular reactive oxygen species (ROS) production

Jeong-Yeh Yang; Mary Anne Della-Fera; Cass Nelson-Dooley; Clifton A. Baile

2006-01-01

36

FGF-2 signaling induces downregulation of TAZ protein in osteoblastic MC3T3-E1 cells  

SciTech Connect

Transcriptional coactivator with PDZ-binding motif (TAZ) protein is a coactivator of Runx2 and corepressor of PPAR{gamma}. It also induces differentiation of mesenchymal cells into osteoblasts. In this study, we found that FGF-2, which inhibits bone mineralization and stimulates cell proliferation, reduced the TAZ protein expression level in osteoblast-like cells, MC3T3-E1. This reduction was recovered by removing FGF-2 from the culture medium, which also restored the osteoblastic features of MC3T3-E1 cells. Furthermore, FGF-2-induced reduction of TAZ is blocked by a SAPK/JNK-specific inhibitor. These findings suggest that the expression of TAZ protein is involved in osteoblast proliferation and differentiation. This may help elucidate the discrepancies in the effect of FGF-2 and contribute to the understanding of FGF/FGFR-associated craniosynostosis syndrome etiology and treatment.

Eda, Homare [Department of Biochemistry, Jikei University School of Medicine, 3-25-8, Nishi-shinbashi, Minato-ku, Tokyo 105-8461 (Japan); Department of Orthopaedic Surgery, Jikei University School of Medicine, 3-25-8, Nishi-shinbashi, Minato-ku, Tokyo 105-8461 (Japan); Aoki, Katsuhiko [Department of Biochemistry, Jikei University School of Medicine, 3-25-8, Nishi-shinbashi, Minato-ku, Tokyo 105-8461 (Japan); Marumo, Keishi; Fujii, Katsuyuki [Department of Orthopaedic Surgery, Jikei University School of Medicine, 3-25-8, Nishi-shinbashi, Minato-ku, Tokyo 105-8461 (Japan); Ohkawa, Kiyoshi [Department of Biochemistry, Jikei University School of Medicine, 3-25-8, Nishi-shinbashi, Minato-ku, Tokyo 105-8461 (Japan)], E-mail: pko@jikei.ac.jp

2008-02-08

37

Functional proteomic analysis of long-term growth factor stimulation and receptor tyrosine kinase coactivation in Swiss 3T3 fibroblasts.  

PubMed

In Swiss 3T3 fibroblasts, long-term stimulation with PDGF, but not insulin-like growth factor 1 (IGF-1) or EGF, results in the establishment of an elongated migratory phenotype, characterized by the formation of retractile dendritic protrusions and absence of actin stress fibers and focal adhesion complexes. To identify receptor tyrosine kinase-specific reorganization of the Swiss 3T3 proteome during phenotypic differentiation, we compared changes in the pattern of protein synthesis and phosphorylation during long-term exposure to PDGF, IGF-1, EGF, and their combinations using 2DE-based proteomics after (35)S- and (33)P-metabolic labeling. One hundred and five differentially regulated proteins were identified by mass spectrometry and some of these extensively validated. PDGF stimulation produced the highest overall rate of protein synthesis at any given time and induced the most sustained phospho-signaling. Simultaneous activation with two or three of the growth factors revealed both synergistic and antagonistic effects on protein synthesis and expression levels with PDGF showing dominance over both IGF-1 and EGF in generating distinct proteome compositions. Using signaling pathway inhibitors, PI3K was identified as an early site for signal diversification, with sustained activity of the PI3K/AKT pathway critical for regulating late protein synthesis and phosphorylation of target proteins and required for maintaining the PDGF-dependent motile phenotype. Several proteins were identified with novel PI3K/Akt-dependent synthesis and phosphorylations including eEF2, PRS7, RACK-1, acidic calponin, NAP1L1, Hsp73, and fascin. The data also reveal induction/suppression of key F-actin and actomyosin regulators and chaperonins that enable PDGFR to direct the assembly of a motile cytoskeleton, despite simultaneous antagonistic signaling activities. Together, the study demonstrates that long-term exposure to different growth factors results in receptor tyrosine kinase-specific regulation of relatively small subproteomes, and implies that the strength and longevity of receptor tyrosine kinase-specific signals are critical in defining the composition and functional activity of the resulting proteome. PMID:22956732

Nagano, Kohji; Akpan, Akunna; Warnasuriya, Gayathri; Corless, Steven; Totty, Nick; Yang, Alice; Stein, Robert; Zvelebil, Marketa; Stensballe, Allan; Burlingame, Al; Waterfield, Michael; Cramer, Rainer; Timms, John F; Naaby-Hansen, Sřren

2012-12-01

38

Protective effect of apocynin on antimycin A-induced cell damage in osteoblastic MC3T3-E1 cells.  

PubMed

Apocynin is a naturally occurring methoxy-substituted catechol, experimentally used as an inhibitor of NADPH-oxidase. In the present study, we investigated the protective effects of apocynin on antimycin A (AMA)-induced toxicicy in osteoblastic MC3T3-E1 cells. Exposure of MC3T3-E1 cells to AMA caused significant cell viability loss, as well as mitochondrial membrane potential (MMP) dissipation, complex IV inactivation, ATP loss, intracellular calcium ([Ca2+]i) elevation and oxidative stress. Pretreatment with apocynin prior to AMA exposure significantly reduced AMA-induced cell damage by preventing MMP dissipation, complex IV inactivation, ATP loss, [Ca2+]i elevation and oxidative stress. These results suggest that apocynin has a protective effect against AMA-induced cell damage by its antioxidant effects and the attenuation of mitochondrial dysfunction. Apocynin also induced the activation of PI3K (phosphoinositide 3-kinase), Akt (protein kinase B) and CREB (cAMP-response element-binding protein) inhibited by AMA. All these data indicate that apocynin may reduce or prevent osteoblasts degeneration in osteoporosis or other degenerative disorders. PMID:21538410

Choi, Eun Mi; Lee, Young Soon

2012-09-01

39

A Nanodot Array Modulates Cell Adhesion and Induces an Apoptosis-Like Abnormality in NIH-3T3 Cells  

PubMed Central

Micro-structures that mimic the extracellular substratum promote cell growth and differentiation, while the cellular reaction to a nanostructure is poorly defined. To evaluate the cellular response to a nanoscaled surface, NIH 3T3 cells were grown on nanodot arrays with dot diameters ranging from 10 to 200 nm. The nanodot arrays were fabricated by AAO processing on TaN-coated wafers. A thin layer of platinum, 5 nm in thickness, was sputtered onto the structure to improve biocompatibility. The cells grew normally on the 10-nm array and on flat surfaces. However, 50-nm, 100-nm, and 200-nm nanodot arrays induced apoptosis-like events. Abnormality was triggered after as few as 24 h of incubation on a 200-nm dot array. For cells grown on the 50-nm array, the abnormality started after 72 h of incubation. The number of filopodia extended from the cell bodies was lower for the abnormal cells. Immunostaining using antibodies against vinculin and actin filament was performed. Both the number of focal adhesions and the amount of cytoskeleton were decreased in cells grown on the 100-nm and 200-nm arrays. Pre-coatings of fibronectin (FN) or type I collagen promoted cellular anchorage and prevented the nanotopography-induced programed cell death. In summary, nanotopography, in the form of nanodot arrays, induced an apoptosis-like abnormality for cultured NIH 3T3 cells. The occurrence of the abnormality was mediated by the formation of focal adhesions. PMID:20596320

2009-01-01

40

A Nanodot Array Modulates Cell Adhesion and Induces an Apoptosis-Like Abnormality in NIH-3T3 Cells  

NASA Astrophysics Data System (ADS)

Micro-structures that mimic the extracellular substratum promote cell growth and differentiation, while the cellular reaction to a nanostructure is poorly defined. To evaluate the cellular response to a nanoscaled surface, NIH 3T3 cells were grown on nanodot arrays with dot diameters ranging from 10 to 200 nm. The nanodot arrays were fabricated by AAO processing on TaN-coated wafers. A thin layer of platinum, 5 nm in thickness, was sputtered onto the structure to improve biocompatibility. The cells grew normally on the 10-nm array and on flat surfaces. However, 50-nm, 100-nm, and 200-nm nanodot arrays induced apoptosis-like events. Abnormality was triggered after as few as 24 h of incubation on a 200-nm dot array. For cells grown on the 50-nm array, the abnormality started after 72 h of incubation. The number of filopodia extended from the cell bodies was lower for the abnormal cells. Immunostaining using antibodies against vinculin and actin filament was performed. Both the number of focal adhesions and the amount of cytoskeleton were decreased in cells grown on the 100-nm and 200-nm arrays. Pre-coatings of fibronectin (FN) or type I collagen promoted cellular anchorage and prevented the nanotopography-induced programed cell death. In summary, nanotopography, in the form of nanodot arrays, induced an apoptosis-like abnormality for cultured NIH 3T3 cells. The occurrence of the abnormality was mediated by the formation of focal adhesions.

Pan, Hsu-An; Hung, Yao-Ching; Su, Chia-Wei; Tai, Shih-Ming; Chen, Chiun-Hsun; Ko, Fu-Hsiang; Steve Huang, G.

2009-08-01

41

Killing two birds with one stone: trans-kingdom suppression of PAMP/MAMP-induced immunity by T3E from enteropathogenic bacteria.  

PubMed

Within the past decade, remarkable similarities between the molecular organization of animal and plant systems for non-self discrimination were revealed. Obvious parallels exist between the molecular structures of the receptors mediating the recognition of pathogen- or microbe-associated molecular patterns (PAMPs/MAMPs) with plant pattern recognition receptors strikingly resembling mammalian Toll-like receptors. Mitogen-activated protein kinase cascades, leading to the transcriptional activation of immunity-associated genes, illustrate the conservation of whole molecular building blocks of PAMP/MAMP-induced signaling. Enteropathogenic Salmonella and Escherichia coli use a type three secretion system (T3SS) to inject effector proteins into the mammalian host cell to subvert defense mechanisms and promote gut infection. Lately, disease occurrence was increasingly associated with bacteria-contaminated fruits and vegetables and common themes have emerged with regard to whether and how effectors target innate immune responses in a trans-kingdom manner. We propose that numerous Salmonella or E. coli effectors may be active in planta and tend to target central components (hubs) of immune signaling pathways. PMID:25101059

Fraiture, Malou; Brunner, Frédéric

2014-01-01

42

Killing two birds with one stone: trans-kingdom suppression of PAMP/MAMP-induced immunity by T3E from enteropathogenic bacteria  

PubMed Central

Within the past decade, remarkable similarities between the molecular organization of animal and plant systems for non-self discrimination were revealed. Obvious parallels exist between the molecular structures of the receptors mediating the recognition of pathogen- or microbe-associated molecular patterns (PAMPs/MAMPs) with plant pattern recognition receptors strikingly resembling mammalian Toll-like receptors. Mitogen-activated protein kinase cascades, leading to the transcriptional activation of immunity-associated genes, illustrate the conservation of whole molecular building blocks of PAMP/MAMP-induced signaling. Enteropathogenic Salmonella and Escherichia coli use a type three secretion system (T3SS) to inject effector proteins into the mammalian host cell to subvert defense mechanisms and promote gut infection. Lately, disease occurrence was increasingly associated with bacteria-contaminated fruits and vegetables and common themes have emerged with regard to whether and how effectors target innate immune responses in a trans-kingdom manner. We propose that numerous Salmonella or E. coli effectors may be active in planta and tend to target central components (hubs) of immune signaling pathways. PMID:25101059

Fraiture, Malou; Brunner, Frederic

2014-01-01

43

Negative trans-regulation of T-cell antigen receptor/T3 complex mRNA expression in murine T-lymphoma somatic cell hybrids.  

PubMed Central

The antigen-specific T-cell receptor (TCR) is composed of variable antigen-recognition chains TCR-alpha and TCR-beta in noncovalent association with the invariant T3 multimer. The TCR-alpha and TCR-beta chains are encoded by gene segments that must be juxtaposed by rearrangement in order to be expressed. To examine whether mechanisms other than gene rearrangement might regulate TCR/T3 gene expression, somatic cell hybrids were formed among closely related murine SL12 T-lymphoma clones that differ in TCR/T3 mRNA levels. In hybrid cells formed between cell clones in which one parent is TCR-beta+ and the other is TCR-beta-, the resultant hybrid cells lack detectable TCR-beta transcripts. Since the protein synthesis inhibitor cycloheximide partially reverses TCR-beta repression in the hybrid cells, we postulate that a labile repressor protein is involved. The amount of mRNA encoding one of the T3 polypeptide chains, T3-delta, is also strongly negatively transregulated in the same hybrid cells in which TCR-beta mRNA expression is repressed. The negative trans-regulation of TCR-beta and T3-delta mRNA expression is relatively specific, since the levels of TCR-alpha mRNA and several thymocyte surface antigens are not repressed in somatic cell hybrids. Our results indicate that rearrangement of the TCR genes alone is not sufficient for TCR-beta expression and that trans-acting factors regulate the amounts of both TCR-beta and T3-delta mRNA in this system. Images PMID:3092223

MacLeod, C L; Minning, L; Gold, D P; Terhorst, C; Wilkinson, M

1986-01-01

44

Negative trans-regulation of T-cell antigen receptor/T3 complex mRNA expression in murine T-lymphoma somatic cell hybrids.  

PubMed

The antigen-specific T-cell receptor (TCR) is composed of variable antigen-recognition chains TCR-alpha and TCR-beta in noncovalent association with the invariant T3 multimer. The TCR-alpha and TCR-beta chains are encoded by gene segments that must be juxtaposed by rearrangement in order to be expressed. To examine whether mechanisms other than gene rearrangement might regulate TCR/T3 gene expression, somatic cell hybrids were formed among closely related murine SL12 T-lymphoma clones that differ in TCR/T3 mRNA levels. In hybrid cells formed between cell clones in which one parent is TCR-beta+ and the other is TCR-beta-, the resultant hybrid cells lack detectable TCR-beta transcripts. Since the protein synthesis inhibitor cycloheximide partially reverses TCR-beta repression in the hybrid cells, we postulate that a labile repressor protein is involved. The amount of mRNA encoding one of the T3 polypeptide chains, T3-delta, is also strongly negatively transregulated in the same hybrid cells in which TCR-beta mRNA expression is repressed. The negative trans-regulation of TCR-beta and T3-delta mRNA expression is relatively specific, since the levels of TCR-alpha mRNA and several thymocyte surface antigens are not repressed in somatic cell hybrids. Our results indicate that rearrangement of the TCR genes alone is not sufficient for TCR-beta expression and that trans-acting factors regulate the amounts of both TCR-beta and T3-delta mRNA in this system. PMID:3092223

MacLeod, C L; Minning, L; Gold, D P; Terhorst, C; Wilkinson, M

1986-09-01

45

Regulation of apelin and its receptor expression in adipose tissues of obesity rats with hypertension and cultured 3T3-L1 adipocytes.  

PubMed

The apelin/APJ system has been implicated in obesity-related hypertension. We investigated the mechanism responsible for the pathogenesis of obesity-related hypertension with a special focus on the crosstalk between AngII/its type 1 receptor (AT1R) signaling and apelin/APJ expression. Sprague-Dawley rats fed a high-fat (obesity-related hypertension, OH) or normal-fat diet (NF) for 15 weeks were randomly assigned to one of two groups and administered vehicle or perindopril for 4 weeks. Compared to the NF rats, the OH rats showed lower levels of plasma apelin and apelin/APJ mRNAs of perirenal adipose tissues, and these changes were restored by perindopril. Administration of the AT1R antagonist olmesartan resulted in the restoration of the reduction of apelin and APJ expressions induced by AngII for 48 h in 3T3-L1 adipocytes. Among several inhibitors for extracellular signal-regulated kinases 1/2 (ERK1/2) PD98059, p38 mitogen-activated protein kinase (p38MAPK) SB203580 and phosphatidylinositol 3-kinase (PI3K) LY294002, the latter showed an additive effect on AngII-mediated inhibitory effects. In addition, the levels of p-Akt, p-ERK and p38MAPK proteins were decreased by long-term treatment with AngII (120 min), and these changes were restored by Olmesartan. Apelin/APJ appears to be impaired in obesity-related hypertension. The AngII inhibition-mediated beneficial effects are likely attributable, at least in part, to restoration of p38/ERK-dependent apelin/APJ expression in diet-induced obesity-related hypertension. PMID:24770651

Wu, Hongxian; Cheng, Xian Wu; Hao, Changning; Zhang, Zhi; Yao, Huali; Murohara, Toyoaki; Dai, Qiuyan

2014-01-01

46

Changes in chromatin structure in NIH 3T3 cells induced by valproic acid and trichostatin A.  

PubMed

Valproic acid (VPA) and trichostatin A (TSA) are known histone deacetylase inhibitors (HDACIs) with epigenetic activity that affect chromatin supra-organization, nuclear architecture, and cellular proliferation, particularly in tumor cells. In this study, chromatin remodeling with effects extending to heterochromatic areas was investigated by image analysis in non-transformed NIH 3T3 cells treated for different periods with different doses of VPA and TSA under conditions that indicated no loss of cell viability. Image analysis revealed chromatin decondensation that affected not only euchromatin but also heterochromatin, concomitant with a decreased activity of histone deacetylases and a general increase in histone H3 acetylation. Heterochromatin protein 1-? (HP1-?), identified immunocytochemically, was depleted from the pericentromeric heterochromatin following exposure to both HDACIs. Drastic changes affecting cell proliferation and micronucleation but not alteration in CCND2 expression and in ratios of Bcl-2/Bax expression and cell death occurred following a 48-h exposure of the NIH 3T3 cells particularly in response to higher doses of VPA. Our results demonstrated that even low doses of VPA (0.05?mM) and TSA (10?ng/ml) treatments for 1?h can affect chromatin structure, including that of the heterochromatin areas, in non-transformed cells. HP1-? depletion, probably related to histone demethylation at H3K9me3, in addition to the effect of VPA and TSA on histone H3 acetylation, is induced on NIH 3T3 cells. Despite these facts, alterations in cell proliferation and micronucleation, possibly depending on mitotic spindle defects, require a longer exposure to higher doses of VPA and TSA. PMID:24913611

Felisbino, Marina Barreto; Gatti, Maria Silvia Viccari; Mello, Maria Luiza S

2014-11-01

47

Alliin, a Garlic (Allium sativum) Compound, Prevents LPS-Induced Inflammation in 3T3-L1 Adipocytes  

PubMed Central

Garlic (Allium sativum L.) has been used to alleviate a variety of health problems due to its high content of organosulfur compounds and antioxidant activity. The main active component is alliin (S-allyl cysteine sulfoxide), a potent antioxidant with cardioprotective and neuroprotective actions. In addition, it helps to decrease serum levels of glucose, insulin, triglycerides, and uric acid, as well as insulin resistance, and reduces cytokine levels. However its potential anti-inflammatory effect is unknown. We examined the effects of alliin in lipopolysaccharide- (LPS-) stimulated 3T3-L1 adipocytes by RT-PCR, Western blot, and microarrays analysis of 22,000 genes. Incubation of cells for 24?h with 100??mol/L alliin prevented the increase in the expression of proinflammatory genes, IL-6, MCP-1, and Egr-1 in 3T3-L1 adipocytes exposed to 100?ng/mL LPS for 1?h. Interestingly, the phosphorylation of ERK1/2, which is involved in LPS-induced inflammation in adipocytes, was decreased following alliin treatment. Furthermore, the gene expression profile by microarrays evidentiate an upregulation of genes involved in immune response and downregulation of genes related with cancer. The present results have shown that alliin is able to suppress the LPS inflammatory signals by generating an anti-inflammatory gene expression profile and by modifying adipocyte metabolic profile. PMID:24453416

Quintero-Fabian, Saray; Ortuno-Sahagun, Daniel; Vazquez-Carrera, Manuel; Lopez-Roa, Rocio Ivette

2013-01-01

48

PPAR? agonist fenofibrate attenuates TNF-?-induced CD40 expression in 3T3-L1 adipocytes via the SIRT1-dependent signaling pathway  

SciTech Connect

The ligand-activated transcription factor peroxisome proliferator-activated receptor-? (PPAR?) participates in the regulation of cellular inflammation. More recent studies indicated that sirtuin1 (SIRT1), a NAD{sup +}-dependent deacetylase, regulates the inflammatory response in adipocytes. However, whether the role of PPAR? in inflammation is mediated by SIRT1 remains unclear. In this study, we aimed to determine the effect of PPAR? agonist fenofibrate on the expressions of SIRT1 and pro-inflammatory cytokine CD40 and underlying mechanisms in 3T3-L1 adipocytes. We found that fenofibrate inhibited CD40 expression and up-regulated SIRT1 expression in tumor necrosis factor-? (TNF-?)-stimulated adipocytes, and these effects of fenofibrate were reversed by PPAR? antagonist GW6471. Moreover, SIRT1 inhibitors sirtinol/nicotinamide (NAM) or knockdown of SIRT1 could attenuate the effect of fenofibrate on TNF-?-induced CD40 expression in adipocytes. Importantly, NF-?B inhibitor pyrrolidine dithiocarbamate (PDTC) augmented the effect of fenofibrate on CD40 expression in adipocytes. Further study found that fenofibrate decreased the expression of acetylated-NF-?B p65 (Ac-NF-?B p65) in TNF-?-stimulated adipocytes, and the effect of fenofibrate was abolished by SIRT1 inhibition. In addition, fenofibrate up-regulated SIRT1 expression through AMPK in TNF-?-stimulated adipocytes. Taken together, these findings indicate that PPAR? agonist fenofibrate inhibits TNF-?-induced CD40 expression in 3T3-L1 adipocytes via the SIRT1-dependent signaling pathway. -- Highlights: • Fenofibrate up-regulates SIRT1 expression in TNF-?-stimulated adipocytes. • Fenofibrate inhibits CD40 expression through SIRT1 in adipocytes. • The effects of fenofibrate on CD40 and SIRT1 expressions are dependent on PPAR?. • Fenofibrate inhibits CD40 expression via SIRT1-dependent deacetylation of NF-?B. • Fenofibrate increases SIRT1 expression through PPAR? and AMPK in adipocytes.

Wang, Weirong [Department of Pharmacology, Cardiovascular Research Center, School of Medicine, Xi'an Jiaotong University, Xi'an, Shaanxi 710061 (China); Lin, Qinqin [Physical Education College, Yanshan University, Qinhuangdao, Hebei 066004 (China); Lin, Rong, E-mail: linrong63@yahoo.com.cn [Department of Pharmacology, Cardiovascular Research Center, School of Medicine, Xi'an Jiaotong University, Xi'an, Shaanxi 710061 (China); Zhang, Jiye [Faculty of Pharmacy, School of Medicine, Xi'an Jiaotong University, Xi'an, Shaanxi 710061 (China); Ren, Feng; Zhang, Jianfeng; Ji, Meixi; Li, Yanxiang [Department of Pharmacology, Cardiovascular Research Center, School of Medicine, Xi'an Jiaotong University, Xi'an, Shaanxi 710061 (China)

2013-06-10

49

Fluid shear-induced mechanical signaling in MC3T3-E1 osteoblasts requires cytoskeleton-integrin interactions  

NASA Technical Reports Server (NTRS)

Mechanical stimulation of bone induces new bone formation in vivo and increases the metabolic activity and gene expression of osteoblasts in culture. We investigated the role of the actin cytoskeleton and actin-membrane interactions in the transmission of mechanical signals leading to altered gene expression in cultured MC3T3-E1 osteoblasts. Application of fluid shear to osteoblasts caused reorganization of actin filaments into contractile stress fibers and involved recruitment of beta1-integrins and alpha-actinin to focal adhesions. Fluid shear also increased expression of two proteins linked to mechanotransduction in vivo, cyclooxygenase-2 (COX-2) and the early response gene product c-fos. Inhibition of actin stress fiber development by treatment of cells with cytochalasin D, by expression of a dominant negative form of the small GTPase Rho, or by microinjection into cells of a proteolytic fragment of alpha-actinin that inhibits alpha-actinin-mediated anchoring of actin filaments to integrins at the plasma membrane each blocked fluid-shear-induced gene expression in osteoblasts. We conclude that fluid shear-induced mechanical signaling in osteoblasts leads to increased expression of COX-2 and c-Fos through a mechanism that involves reorganization of the actin cytoskeleton. Thus Rho-mediated stress fiber formation and the alpha-actinin-dependent anchorage of stress fibers to integrins in focal adhesions may promote fluid shear-induced metabolic changes in bone cells.

Pavalko, F. M.; Chen, N. X.; Turner, C. H.; Burr, D. B.; Atkinson, S.; Hsieh, Y. F.; Qiu, J.; Duncan, R. L.

1998-01-01

50

Mechanically induced c-fos expression is mediated by cAMP in MC3T3-E1 osteoblasts  

NASA Technical Reports Server (NTRS)

In serum-deprived MC3T3-E1 osteoblasts, mechanical stimulation caused by mild (287 x g) centrifugation induced a 10-fold increase in mRNA levels of the proto-oncogene, c-fos. Induction of c-fos was abolished by the cAMP-dependent protein kinase inhibitor H-89, suggesting that the transient c-fos mRNA increase is mediated by cAMP. Down-regulation of protein kinase C (PKC) activity by chronic TPA treatment failed to significantly reduce c-fos induction, suggesting that TPA-sensitive isoforms of PKC are not responsible for c-fos up-regulation. In addition, 287 x g centrifugation increased intracellular prostaglandin E2 (PGE2) levels 2.8-fold (P<0. 005). Since we have previously shown that prostaglandin E2 (PGE2) can induce c-fos expression via a cAMP-mediated mechanism, we asked whether the increase in c-fos mRNA was due to centrifugation-induced PGE2 release. Pretreatment with the cyclooxygenase inhibitors indomethacin and flurbiprofen did not hinder the early induction of c-fos by mechanical stimulation. We conclude that c-fos expression induced by mild mechanical loading is dependent primarily on cAMP, not PKC, and initial induction of c-fos is not necessarily dependent on the action of newly synthesized PGE2.

Fitzgerald, J.; Hughes-Fulford, M.

1999-01-01

51

Chromosomal locations of the gene coding for the CD3 (T3) gamma subunit of the human and mouse CD3/T-cell antigen receptor complexes.  

PubMed

The gene coding for the Mr 26000 gamma chain of the human CD3 (T3) antigen/T-cell antigen receptor complex was mapped to chromosome band 11q23 by using a cDNA clone (pJ6T3 gamma-2), by in situ hybridization to metaphase chromosomes and by Southern blot analysis of a panel of human-rodent somatic cell hybrids. The mouse homolog, here termed Cdg-3, was mapped to chromosome 9 using the mouse gamma cDNA clone pB10.AT3 gamma-1 and a panel of mouse-hamster somatic cell hybrids. Similar locations for the CD3 delta genes have been described previously. Thus, the corporate results indicate that the CD3 gamma and delta genes have remained together since they duplicated about 200 million years ago. PMID:2820874

Krissansen, G W; Gorman, P A; Kozak, C A; Spurr, N K; Sheer, D; Goodfellow, P N; Crumpton, M J

1987-01-01

52

Curcumin improves hypoxia induced dysfunctions in 3T3-L1 adipocytes by protecting mitochondria and down regulating inflammation.  

PubMed

Obesity induced metabolic syndrome is increasing worldwide at an alarming rate. It is characterized by excessive expansion of white adipose tissue which leads to hypoxia and impairs normal metabolism. Recent studies reveal that hypoxia could be one of the factors for inflammation, insulin resistance and other obesity related complications. There is a high demand for anti-obese phytoceuticals to control and manage the complications resulting from obesity. In this study, we investigated how hypoxia affect the physiological functions of 3T3-L1 adipocytes emphasizing on oxidative stress, inflammation, and mitochondrial functions. We also evaluated the protective role of various doses of curcumin, a well-known dietary antioxidant, on hypoxia induced alterations. The results revealed that hypoxia significantly altered the vital parameters of adipocyte biology like HIF 1? expression (103.47% ?), lactate, and glycerol release (184.34% and 69.1% ?, respectively), reactive oxygen species production (432.53% ?), lipid and protein oxidation (376.6% and 566.6% ?, respectively), reduction in antioxidant enzymes (superoxide dismutase and catalase) status, secretion of inflammatory markers (TNF ?, IL 6, IL 1?, and IFN ?), and mitochondrial functions (mitochondrial mass, membrane potential, permeability transition pore integrity, and superoxide generation). Curcumin substantially protected adipocytes from toxic effects of hypoxia in a dose dependent manner by protecting mitochondria and down regulating inflammation. Acriflavine is used as a positive control. A detailed investigation is required for the development of curcumin as an effective nutraceutical against obesity. © 2014 BioFactors, 40(5):513-523, 2014. PMID:25110893

Priyanka, Ariyapalli; Anusree, Sasidharan Suseela; Nisha, Vijayakumar Marykutty; Raghu, Kozhiparambil Gopalan

2014-09-10

53

Insulin Induces an Increase in Cytosolic Glucose Levels in 3T3-L1 Cells with Inhibited Glycogen Synthase Activation  

PubMed Central

Glucose is an important source of energy for mammalian cells and enters the cytosol via glucose transporters. It has been thought for a long time that glucose entering the cytosol is swiftly phosphorylated in most cell types; hence the levels of free glucose are very low, beyond the detection level. However, the introduction of new fluorescence resonance energy transfer-based glucose nanosensors has made it possible to measure intracellular glucose more accurately. Here, we used the fluorescent indicator protein (FLIPglu-600µ) to monitor cytosolic glucose dynamics in mouse 3T3-L1 cells in which glucose utilization for glycogen synthesis was inhibited. The results show that cells exhibit a low resting cytosolic glucose concentration. However, in cells with inhibited glycogen synthase activation, insulin induced a robust increase in cytosolic free glucose. The insulin-induced increase in cytosolic glucose in these cells is due to an imbalance between the glucose transported into the cytosol and the use of glucose in the cytosol. In untreated cells with sensitive glycogen synthase activation, insulin stimulation did not result in a change in the cytosolic glucose level. This is the first report of dynamic measurements of cytosolic glucose levels in cells devoid of the glycogen synthesis pathway. PMID:25279585

Chowdhury, Helena H.; Kreft, Marko; Jensen, J?rgen; Zorec, Robert

2014-01-01

54

Insulin-like growth factor-1 receptor signaling in 3T3-L1 adipocyte differentiation requires lipid rafts but  

E-print Network

- sidered as a subtype of lipid rafts and only formed in cells expressing caveolin-1. If the cells become.2.04 Edited by Dr G Melino Abstract Previously, we have found that lipid rafts/caveolae were essential not affect the caveolinless lipid rafts or the localization of IGF-1 receptor in lipid rafts on plasma

Tian, Weidong

55

Lipoprotein Lipase Suppression in 3T3-L1 Cells by an Endotoxin-Induced Mediator from Exudate Cells  

Microsoft Academic Search

Conditioned medium from cultures of mouse peritoneal exudate cells incubated with endotoxin contains a mediator that markedly suppresses (>90%) lipoprotein lipase (triacylglycero-protein acylhydrolase, EC 3.1.1.34) activity in differentiating 3T3-L1 mouse preadipocytes. The effect is dependent upon the amount of mediator and is evident as early as 30 min after the addition of the mediator-containing medium to 3T3-L1 cell cultures. Neither

Masanobu Kawakami; Phillip H. Pekala; Anthony Cerami

1982-01-01

56

Regulation of the beta-adrenergic receptor-adenylate cyclase complex of 3T3-L1 fibroblasts by sodium butyrate  

SciTech Connect

Mouse 3T3-L1 fibroblasts contain beta-adrenergic receptors (BAR), predominantly of the B/sub 1/ subtype. Incubation of these cells with 2-10 mM sodium butyrate (SB) for 24-48 hr results in a switch in the BAR subtype from B/sub 1/ to B/sub 2/ and promotes a 1.5 to 2.5 fold increase in total BAR number. Other short chain acids were not as effective as SB in promoting changes in BAR. BAR were assayed in membranes prepared from the 3T3-L1 cells using the radiolabeled antagonist (/sup 125/I)-cyanopindolol and the B/sub 2/ selective antagonist ICI 118.551. BAR subtype switch was confirmed functionally by measuring cellular cAMP accumulation in response to agonists. The structure and amount of the alpha subunits of the guanine nucleotide regulatory proteins N/sub s/ and N/sub i/ were determined by ADP-ribosylation using /sup 32/P-NAD and either cholera toxin or pertussis toxin for labeling of the respective subunits. Preincubation of cells with 5 mM SB for 48 hr resulted in a 2-3 fold increase in the labeling of the alpha subunits of both N/sub s/ and N/sub i/. A protein of M/sub r/ = 44,000 showed enhanced labeling by cholera toxin following SB treatment of the cells. These data indicate SB concomitantly regulates expression of BAR subtype and components of the adenylate cyclase in 3T3-L1 cells.

Stadel, J.M.; Poksay, K.S.; Nakada, M.T.; Crooke, S.T.

1986-05-01

57

Phosphorylation of the human transferrin receptor by protein kinase C is not required for endocytosis and recycling in mouse 3T3 cells.  

PubMed Central

We have investigated the role of phosphorylation in the endocytosis of the human transferrin receptor (TR) by replacing its phosphorylation site, Ser24, with Ala through site-directed mutagenesis of the TR cDNA. The TR Ala24 mutant expressed in mouse 3T3 cells was not phosphorylated, even following stimulation of protein kinase C by phorbol ester. However, in spite of this defect the mutant was efficiently endocytosed and recycled back to the plasma membrane with kinetics similar to those of TR and a control mutant TR Ala63. Thus, these results confirm earlier results by Davis et al. (1986, J. Biol. Chem., 261-9034-9041) that Ser24 of human TR is the phosphorylation site for protein kinase C but do not support a role of this modification as a signal for TR endocytosis and recycling. Images Fig. 1. Fig. 2. Fig. 3. PMID:3479328

Zerial, M; Suomalainen, M; Zanetti-Schneider, M; Schneider, C; Garoff, H

1987-01-01

58

Proteomics of Oxidative Stress Using Inducible CYP2E1 Expressing HepG2 Cells and 3T3-L1 Adipocytes as Model Systems  

E-print Network

The overall goal of this research was to investigate oxidative stress related changes to the proteomes of 3T3-L1 adipocytes and an inducible CYP2E1 expressing HepG2 cells. Enhanced oxidative stress in hypertrophic adipocytes is associated...

Newton, Billy Walker

2012-07-16

59

Basic fibroblast growth factor binds its receptors, is internalized, and stimulates DNA synthesis in Balb/c3T3 cells in the absence of heparan sulfate.  

PubMed

We have investigated the interaction of basic fibroblast growth factor (bFGF) with its receptors and heparan sulfate proteoglycans (HSPG). It has been suggested that in the absence of HSPG, cells are not able to bind bFGF or respond to treatment with bFGF. In our studies, Balb/c3T3 fibroblasts were treated with 50 mM sodium chlorate to completely inhibit (99%) sulfation of proteoglycans. We found that bFGF was able to bind, be internalized, and stimulate DNA synthesis in the absence of HSPG in a dose-dependent manner. bFGF bound to its receptors on chlorate-treated cells with a lower apparent affinity and no change in receptor number. To determine if this decreased affinity bFGF-receptor interaction is functional, we quantitatively analyzed bFGF internalization and stimulation of DNA synthesis in control and chlorate-treated cells. Endocytotic rate constants (ke) for chlorate-treated and control cells were ke = 0. 078 +/- 0.022 min-1 and ke = 0.043 +/- 0.012 min-1, respectively, suggesting that the process of bFGF internalization is not dramatically altered by HSPG. bFGF stimulated DNA synthesis to the same maximal level under both conditions, but chlorate-treated cells were significantly less responsive at low bFGF doses (approximately 10-fold increase in ED50). The differences observed for control and chlorate-treated cells in the dose-response curves for stimulation of DNA synthesis and receptor binding correlated directly, suggesting that receptors are equally capable of eliciting a mitogenic signal under both conditions. It is unlikely that these results are due to residual HSPG since heparinase (I and III) digestion of chlorate-treated cells had little effect. Although the presence of HSPG on the cell surface increases the affinity of bFGF for its receptors, our observations suggest that HSPG are not "absolutely" required for binding, internalization, or stimulation of mitogenic activity. PMID:8663512

Fannon, M; Nugent, M A

1996-07-26

60

Receptor-mediated inhibition of adenylate cyclase and stimulation of arachidonic acid release in 3T3 fibroblasts. Selective susceptibility to islet-activating protein, pertussis toxin  

SciTech Connect

Thrombin exhibited diverse effects on mouse 3T3 fibroblasts. It (a) decreased cAMP in the cell suspension, (b) inhibited adenylate cyclase in the Lubrol-permeabilized cell suspension in a GTP-dependent manner, increased releases of (c) arachidonic acid and (d) inositol from the cell monolayer prelabeled with these labeled compounds, (e) increased /sup 45/Ca/sup 2 +/ uptake into the cell monolayer, and (f) increased /sup 86/Rb/sup +/ uptake into the cell monolayer in a ouabain-sensitive manner. Most of the effects were reproduced by bradykinin, platelet-activating factor, and angiotensin II. The receptors for these agonists are thus likely to be linked to three separate effector systems: the adenylate cyclase inhibition, the phosphoinositide breakdown leading to Ca/sup 2 +/ mobilization and phospholipase A2 activation, and the Na,K-ATPase activation. Among the effects of these agonists, (a), (b), (c), and (e) were abolished, but (d) and (f) were not, by prior treatment of the cells with islet-activating protein (IAP), pertussis toxin, which ADP-ribosylates the Mr = 41,000 protein, the alpha-subunit of the inhibitory guanine nucleotide regulatory protein (Ni), thereby abolishing receptor-mediated inhibition of adenylate cyclase. The effects (a), (c), (d), and (e) of thrombin, but not (b), were mimicked by A23187, a calcium ionophore. The effects of A23187, in contrast to those of receptor agonists, were not affected by the treatment of cells with IAP. Thus, the IAP substrate, the alpha-subunit of Ni, or the protein alike, may play an additional role in signal transduction arising from the Ca/sup 2 +/-mobilizing receptors, probably mediating process(es) distal to phosphoinositide breakdown and proximal to Ca/sup 2 +/ gating.

Murayama, T.; Ui, M.

1985-06-25

61

(-)-Epicatechin prevents TNF?-induced activation of signaling cascades involved in inflammation and insulin sensitivity in 3T3-L1 adipocytes  

PubMed Central

Obesity is major public health concern worldwide and obese individuals exhibit a higher risk of chronic diseases such as type 2 diabetes. Inflammation plays a significant role in metabolic regulation and mounting evidence highlight the contribution of adipose tissue to systemic inflammatory state. Food extracts with a high content of (-)-epicatechin have been found to exert systemic anti-inflammatory actions, however the anti-inflammatory actions of (-)-epicatechin on adipose tissue remain to be determined. The aim of this study was to investigate the capacity of (-)-epicatechin to prevent tumor necrosis alpha (TNF?)-induced activation of cell signals involved in inflammation and insulin resistance (NF-?B, mitogen-activated protein kinases (MAPKs), AP-1, and peroxisome proliferator activated receptor ? (PPAR?)) in differentiated white adipocytes (3T3-L1). TNF? triggered the activation of transcription factors NF-?B and AP-1, and MAPKs ERK1/2, JNK, and p38. (-)-Epicatechin caused a dose (0.5-10 ?M)-dependent decrease in TNF?-mediated JNK, ERK1/2, and p-38 phosphorylation, and nuclear AP-1-DNA binding. (-)-Epicatechin also inhibited TNF?-triggered activation of the NF-?B signaling cascade, preventing TNF?-mediated p65 nuclear transport and nuclear NF-?B-DNA binding. (-)-Epicatechin also attenuated the TNF?-mediated downregulation of PPAR? expression and decreased nuclear DNA binding. Accordingly, (-)-epicatechin inhibited TNF?-mediated altered transcription of genes (MCP-1, interleukin-6, TNF?, resistin, and protein-tyrosine phosphatase 1B) involved in inflammation and insulin signaling. In conclusion, (-)-epicatechin can attenuate TNF?-mediated triggering of signaling cascades involved in inflammation and insulin resistance. These findings could be of relevance in the dietary management of obesity and metabolic syndrome. PMID:22425757

Vazquez-Prieto, Marcela A.; Bettaieb, A.; Haj, Fawaz G.; Fraga, Cesar G.; Oteiza, Patricia I.

2012-01-01

62

Cyanidin 3-glucoside protects 3T3-L1 adipocytes against H2O2- or TNF-alpha-induced insulin resistance by inhibiting c-Jun NH2-terminal kinase activation.  

PubMed

Anthocyanins are naturally occurring plant pigments and exhibit an array of pharmacological properties. Our previous study showed that black rice pigment extract rich in anthocyanin prevents and ameliorates high-fructose-induced insulin resistance in rats. In present study, cyanidin 3-glucoside (Cy-3-G), a typical anthocyanin most abundant in black rice was used to examine its protective effect on insulin sensitivity in 3T3-L1 adipocytes exposed to H(2)O(2) (generated by adding glucose oxidase to the medium) or tumor necrosis factor alpha (TNF-alpha). Twelve-hour exposure of 3T3-L1 adipocytes to H(2)O(2) or TNF-alpha resulted in the increase of c-Jun NH(2)-terminal kinase (JNK) activation and insulin receptor substrate 1 (IRS1) serine 307 phosphorylation, concomitantly with the decrease in insulin-stimulated IRS1 tyrosine phosphorylation and cellular glucose uptake. Blocking JNK expression using RNA interference efficiently prevented the H(2)O(2)- or TNF-alpha-induced defects in insulin action. Pretreatment of cells with Cy-3-G reduced the intracellular production of reactive oxygen species, the activation of JNK, and attenuated H(2)O(2)- or TNF-alpha-induced insulin resistance in a dose-dependent manner. In parallel, N-acetyl-cysteine, an antioxidant compound, did not exhibit an attenuation of TNF-alpha-induced insulin resistance. Taken together, these results indicated that Cy-3-G exerts a protective role against H(2)O(2)- or TNF-alpha-induced insulin resistance in 3T3-L1 adipocytes by inhibiting the JNK signal pathway. PMID:18179781

Guo, Honghui; Ling, Wenhua; Wang, Qing; Liu, Chi; Hu, Yan; Xia, Min

2008-03-15

63

Quercetin reversed lipopolysaccharide-induced inhibition of osteoblast differentiation through the mitogen?activated protein kinase pathway in MC3T3-E1 cells.  

PubMed

Quercetin, a flavonoid found in onions and other vegetables, has potential inhibitory effects on bone resorption in vivo and in vitro. In our previous study it was identified that quercetin triggered the apoptosis of lipopolysaccharide (LPS)?induced osteoclasts and inhibited bone resorption. Currently, little information is available detailing the effect of quercetin on osteoblast differentiation and bone formation in bacteria?induced inflammatory diseases. The present study aimed to investigate the effect of quercetin on osteoblast differentiation in MC3T3?E1 osteoblasts stimulated with LPS. LPS significantly downregulated the mRNA expression of osteoblast?related genes in the MC3T3?E1 cells. By contrast, quercetin significantly restored the LPS?suppressed mRNA expression of osteoblast?related genes in a dose?dependent manner. Quercetin also restored the protein expression of Osterix in MC3T3?E1 cells suppressed by LPS. Furthermore, quercetin selectively triggered the activation of the mitogen?activated protein kinase (MAPK) pathway by enhancing the expression of extracellular signal-regulated kinase and reducing the expression of c?Jun N?terminal kinase. These data suggest that quercetin reversed the inhibition of osteoblast differentiation induced by LPS through MAPK signaling. These findings suggest that quercetin may be of potential use as a therapeutic agent to restore osteoblast function in bacteria?induced bone diseases. PMID:25323558

Wang, Xin-Chun; Zhao, Nzhi-Jun; Guo, Chun; Chen, Jing-Tao; Song, Jin-Ling; Gao, Li

2014-12-01

64

Hydrogen sulfide protects MC3T3-E1 osteoblastic cells against H 2O 2-induced oxidative damage—implications for the treatment of osteoporosis  

Microsoft Academic Search

Osteoporosis is a bone disease that leads to an increased risk of fracture. Oxidative damage is an important contributor to the morphological and functional changes in the development of osteoporosis. We found in this study that hydrogen sulfide (H2S), a novel endogenous gaseous mediator, protected MC3T3-E1 osteoblastic cells against hydrogen peroxide (H2O2)-induced oxidative injury. NaHS, an H2S donor, increased cell

Zhong-Shi Xu; Xin-Yu Wang; De-Ming Xiao; Li-Fang Hu; Ming Lu; Zhi-Yuan Wu; Jin-Song Bian

2011-01-01

65

T3RU test  

MedlinePLUS

Resin T3 uptake; T3 resin uptake; Thyroid hormone-binding ratio ... This test is done to check your thyroid function. Thyroid function is complex and depends on the action of many different hormones, including thyroid-stimulating hormone (TSH), T3, and T4. This ...

66

Ethnic differences in the lymphocyte proliferative response induced by a murine IgG1 antibody, Leu-4, to the T3 molecule  

PubMed Central

The mitogenic effects of isotypically diverse antibodies to the T3 molecule were examined in genetically diverse population groups. Whereas the OKT3 antibody (IgG2a) was mitogenic for blood mononuclear cells from all individuals tested, the 38.1 antibody (IgM) was consistently nonmitogenic. In contrast, studies of the mitogenic effects of the Leu-4 antibody (IgG1) revealed striking ethnic differences. More than 80% of Caucasians and Negroes were good Leu-4 responders, whereas most individuals of Asian origin, including Indian, Japanese, and Chinese, were either Leu-4 nonresponders or Leu-4 low responders. However, the majority of American Indians, as well as a significant minority of Chinese, were good responders. Cell separation studies confirmed that monocytes govern the different mitogenic effects of the anti-T3 antibodies. The results reveal interesting ethnic differences in monocyte accessory function probably mediated via the Fc- gamma receptor, in the stimulation of T lymphocytes by an IgG1 antibody against the T3 molecule. PMID:6429266

1984-01-01

67

Mammalian Target of Rapamycin Complex 1 (mTORC1) Plays a Role in Pasteurella multocida Toxin (PMT)-induced Protein Synthesis and Proliferation in Swiss 3T3 Cells*  

PubMed Central

Pasteurella multocida toxin (PMT) is a potent mitogen known to activate several signaling pathways via deamidation of a conserved glutamine residue in the ? subunit of heterotrimeric G-proteins. However, the detailed mechanism behind mitogenic properties of PMT is unknown. Herein, we show that PMT induces protein synthesis, cell migration, and proliferation in serum-starved Swiss 3T3 cells. Concomitantly PMT induces phosphorylation of ribosomal S6 kinase (S6K1) and its substrate, ribosomal S6 protein (rpS6), in quiescent 3T3 cells. The extent of the phosphorylation is time and PMT concentration dependent, and is inhibited by rapamycin and Torin1, the two specific inhibitors of the mammalian target of rapamycin complex 1 (mTORC1). Interestingly, PMT-mediated mTOR signaling activation was observed in MEF WT but not in G?q/11 knock-out cells. These observations are consistent with the data indicating that PMT-induced mTORC1 activation proceeds via the deamidation of G?q/11, which leads to the activation of PLC? to generate diacylglycerol and inositol trisphosphate, two known activators of the PKC pathway. Exogenously added diacylglycerol or phorbol 12-myristate 13-acetate, known activators of PKC, leads to rpS6 phosphorylation in a rapamycin-dependent manner. Furthermore, PMT-induced rpS6 phosphorylation is inhibited by PKC inhibitor, Gö6976. Although PMT induces epidermal growth factor receptor activation, it exerts no effect on PMT-induced rpS6 phosphorylation. Together, our findings reveal for the first time that PMT activates mTORC1 through the G?q/11/PLC?/PKC pathway. The fact that PMT-induced protein synthesis and cell migration is partially inhibited by rapamycin indicates that these processes are in part mediated by the mTORC1 pathway. PMID:23223576

Oubrahim, Hammou; Wong, Allison; Wilson, Brenda A.; Chock, P. Boon

2013-01-01

68

Chicoric acid induces apoptosis in 3T3-L1 preadipocytes through ROS-mediated PI3K/Akt and MAPK signaling pathways.  

PubMed

Chicoric acid has been reported to possess various bioactivities. However, the antiobesity effects of chicoric acid remain poorly understood. In this study, we investigated the effects of chicoric acid on 3T3-L1 preadipocytes and its molecular mechanisms of apoptosis. Chicoric acid inhibited cell viability and induced apoptosis in 3T3-L1 preadipocytes which was characterized by chromatin condensation and poly ADP-ribose-polymerase (PARP) cleavage. Mitochondrial membrane potential (MMP) loss, Bax/Bcl-2 dysregulation, cytochrome c release, and caspase-3 activation were observed, indicating mitochondria-dependent apoptosis induced by chicoric acid. Furthermore, PI3K/Akt and MAPK (p38 MAPK, JNK, and ERK1/2) signaling pathways were involved in chicoric acid-induced apoptosis. The employment of protein kinase inhibitors LY294002, SB203580, SP600125, and U0126 revealed that PI3K/Akt signaling pathway interplayed with MAPK signaling pathways. Moreover, chicoric acid induced reactive oxygen species (ROS) generation. Pretreatment with the antioxidant N-acetylcysteine (NAC) significantly blocked cell death and changes of Akt and MAPK signalings induced by chicoric acid. In addition, chicoric acid down regulated HO-1 and COX-2 via the PI3K/Akt pathway. PMID:23363008

Xiao, Haifang; Wang, Jing; Yuan, Li; Xiao, Chunxia; Wang, Yutang; Liu, Xuebo

2013-02-20

69

Novel ATP-binding heat-inducible protein of Mr = 37,000 that is sensitive to transformation in BALB/3T3 cells  

SciTech Connect

Using affinity chromatography on ATP-agarose, we have identified a major ATP-binding protein in Nonidet P-40 extracts of avian and mammalian cells labeled with (35S)methionine. After washing ATP-agarose beads with high-ionic-strength buffer (0.4 M NaCl), the 37-kD protein was shown to be one of the major ATP-binding proteins while p72 and grp78, which are members of the hsp70 family, also bound to ATP-agarose. This protein consisted of several spots on two-dimensional gel electrophoresis. The isoelectric point of the most basic spot was approximately 9.2 in chick embryo fibroblasts, whereas it was about 8.8 in mouse 3T3 cells. The identities of these proteins in mouse and chick cells were confirmed by peptide mapping. After heat-shock treatment of BALB/3T3 cells, the major heat-shock protein, hsp70, was shown to be induced very rapidly after heat shock and was recovered in the ATP-binding fraction. Besides hsp70, a 37-kD protein was also found to be induced by heat shock. This protein was drastically induced by treating the cells with alpha,alpha'-dipyridyl, an iron chelating reagent, but not with sodium arsenite, calcium ionophore, or tunicamycin. The synthesis and the total amount of this ATP-binding protein increased in mouse 3T3 cells transformed by simian virus 40, methylcholanthrene, or activated c-Ha-ras oncogene compared to their normal counterparts. The incorporation of (32P)orthophosphate was not detected in either normal or transformed cells. These studies established that a major ATP-binding protein of Mr = 37,000 is a heat-inducible protein and that the synthesis of this protein is regulated by malignant transformation.

Nakai, A.; Hirayama, C.; Ohtsuka, K.; Hirayoshi, K.; Nagata, K. (Kyoto Univ. (Japan))

1990-06-01

70

Dynamic pattern of gene expression of ZnT-1, ZnT-3 and PRG-1 in rat brain following flurothyl-induced recurrent neonatal seizures.  

PubMed

Zinc transporters (ZnTs) and plasticity-related genes (PRGs) both play the key roles in the formation of hippocampal mossy fiber sprouting, which is associated with cognitive deficits following developmental seizures. Here, for the first time, we report the timing of expression pattern of ZnT-1, ZnT-3 and PRG-1 in hippocampus and cerebral cortex following developmental seizures. A seizure was induced by inhalant flurothyl daily in neonatal Sprague-Dawley rats from postnatal day 6 (P6). Rats were assigned into the recurrent-seizure group (RS, seizures induced in 6 consecutive days) and the control group. At 1.5 h, 3 h, 6 h, 12 h, 24 h, 48 h, 7 d and 14 d after the last seizures, the mRNA level was detected using RT-PCR method; PRG-1 protein level was examined by Western blotting analysis. At an early period of 12 h and 48 h after the last seizures, both ZnT-1 and ZnT-3 showed significantly down-regulated mRNA level in the cerebral cortex of RS group than those at the corresponding time point in control group. In the long-term time point of 14 d after the last seizure, ZnT-3 mRNA and PRG-1 protein level in hippocampus were up-regulated while the mRNA level of ZnT-1 down-regulated; in addition, there were up-regulated level of both the mRNA and protein level of PRG-1 and down-regulated mRNA level of ZnT-3 in the cerebral cortex of RS group when compared to the control. Taken together, these dates are consistent with an important role for ZnT-1, ZnT-3 and PRG-1 in the pathophysiology of the long-term adverse effects of recurrent neonatal seizure-induced hippocampal mossy fiber sprouting and cognitive deficit. PMID:20167268

Ni, Hong; Jiang, Yu-wu; Xiao, Zhuo-jun; Tao, Lu-yang; Jin, Mei-fang; Wu, Xi-ru

2010-05-01

71

Inhibition of O-GlcNAcase Using a Potent and Cell-Permeable Inhibitor Does Not Induce Insulin Resistance in 3T3-L1 Adipocytes  

PubMed Central

Summary To probe increased O-GlcNAc levels as an independent mechanism governing insulin resistance in 3T3-L1 adipocytes, a new class of O-GlcNAcase (OGA) inhibitor was studied. 6-Acetamido-6-deoxy-castanospermine (6-Ac-Cas) is a potent inhibitor of OGA. The structure of 6-Ac-Cas bound in the active site of an OGA homolog reveals structural features contributing to its potency. Treatment of 3T3-L1 adipocytes with 6-Ac-Cas increases O-GlcNAc levels in a dose-dependent manner. These increases in O-GlcNAc levels do not induce insulin resistance functionally, measured using a 2-deoxyglucose (2-DOG) uptake assay, or at the molecular level, determined by evaluating levels of phosphorylated IRS-1 and Akt. These results, and others described, provide a structural blueprint for improved inhibitors and collectively suggest that increased O-GlcNAc levels, brought about by inhibition of OGA, does not by itself cause insulin resistance in 3T3-L1 adipocytes. PMID:20851343

Macauley, Matthew S.; He, Yuan; Gloster, Tracey M.; Stubbs, Keith A.; Davies, Gideon J.; Vocadlo, David J.

2010-01-01

72

Inhibition of O-GlcNAcase using a potent and cell-permeable inhibitor does not induce insulin resistance in 3T3-L1 adipocytes.  

PubMed

To probe increased O-GlcNAc levels as an independent mechanism governing insulin resistance in 3T3-L1 adipocytes, a new class of O-GlcNAcase (OGA) inhibitor was studied. 6-Acetamido-6-deoxy-castanospermine (6-Ac-Cas) is a potent inhibitor of OGA. The structure of 6-Ac-Cas bound in the active site of an OGA homolog reveals structural features contributing to its potency. Treatment of 3T3-L1 adipocytes with 6-Ac-Cas increases O-GlcNAc levels in a dose-dependent manner. These increases in O-GlcNAc levels do not induce insulin resistance functionally, measured using a 2-deoxyglucose (2-DOG) uptake assay, or at the molecular level, determined by evaluating levels of phosphorylated IRS-1 and Akt. These results, and others described, provide a structural blueprint for improved inhibitors and collectively suggest that increased O-GlcNAc levels, brought about by inhibition of OGA, does not by itself cause insulin resistance in 3T3-L1 adipocytes. PMID:20851343

Macauley, Matthew S; He, Yuan; Gloster, Tracey M; Stubbs, Keith A; Davies, Gideon J; Vocadlo, David J

2010-09-24

73

The protective effects of Achyranthes bidentata root extract on the antimycin A induced damage of osteoblastic MC3T3-E1 cells.  

PubMed

Achyranthes bidentata (A. bidentata) Blume is a medicinal herb with the property of strengthening bones and muscles and ensuring proper downward flow of blood in terms of the therapeutic theory of traditional medicine. In the present study, the effect of A. bidentata root extract (AE) on osteoblast function was investigated in osteoblastic MC3T3-E1 cells. AE caused a significant elevation of alkaline phosphatase activity, collagen synthesis, osteocalcin production, and mineralization in the cells (P < 0.05). AE also decreased the production of TNF-?, IL-6, and RANKL induced by antimycin A, mitochondrial electron transport inhibitor. Exposure of MC3T3-E1 cells to antimycin A caused significant reduction of cell viability and mineralization. However, pretreatment with AE prior to antimycin A exposure significantly reduced antimycin A-induced cell damage by preventing mitochondrial membrane potential dissipation, ATP loss, ROS release, and nitrotyrosine increase, suggesting that AE may be useful for protecting mitochondria against a burst of oxidative stress. Moreover, AE increased the phosphorylation of cAMP-response element-binding protein inhibited by antimycin A. Our study demonstrates that A. bidentata could significantly prevent osteoblast damage in aged patients. PMID:24113920

Suh, Kwang Sik; Lee, Young Soon; Choi, Eun Mi

2014-12-01

74

Ameliorating effects of fermented rice bran extract on oxidative stress induced by high glucose and hydrogen peroxide in 3T3-L1 adipocytes.  

PubMed

In this study, we investigated whether fermented rice bran (FRB) can ameliorate the oxidative stress induced by high glucose and hydrogen peroxide (H(2)O(2)) in 3T3-L1 adipocytes by analyzing reactive oxygen species (ROS), oil red O staining, as well as the expression of mRNAs related to glucose homeostasis and adipogenesis. It was first confirmed that rice bran fermented by Issatchenkia orientalis MFST1 extract increased free phenolic content compared to non-fermented rice bran. The FRB extract strongly inhibited ROS generation and upregulated the expression of PPAR-? and adiponectin. Moreover, FRB upregulated GLUT4 related to glucose transportation and insulin sensitivity. Taken together, FRB extract ameliorated oxidative stress-induced insulin resistance by neutralizing free radicals and upregulating adiponectin in adipocytes. Our results provide information toward understanding the beneficial effects of FRB on oxidative stress. PMID:21748436

Kim, Dongyeop; Han, Gi Dong

2011-09-01

75

T3 (Triiodothyronine) Test  

MedlinePLUS

... then the person may have symptoms associated with hypothyroidism and a slowed metabolism , such as weight gain, ... T4 T3 Interpretation High Normal Normal Mild (subclinical) hypothyroidism High Low Low or normal Hypothyroidism Low Normal ...

76

Eucommia ulmoides Oliv. antagonizes H2O2-induced rat osteoblastic MC3T3-E1 apoptosis by inhibiting expressions of caspases 3, 6, 7, and 9.  

PubMed

Eucommia ulmoides Oliv. (EuO), also known as Duzhong, native to China, has been reported to have antioxidative function, but its cellular mechanism is not fully examined yet. We investigated inhibitory effects of EuO leaf ethanol extracts on H(2)O(2)-induced apoptosis in rat osteoblastic MC3T3-E1 cells and underlying mechanisms. Locally-grown Duzhong leaves were extracted with ethanol. MC3T3-E1 cells were treated with EuO (6.25, 12.5, 25, 50, and 100 µg/ml) for 24 h, and then H(2)O(2) (800 µmol/L) for an additional 24 h. Cell survival rate, percentage of apoptosis, and expressions of caspases 3, 6, 7, and 9 were examined using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, microscopic analysis, Western blotting, and reverse transcription polymerase chain reaction (RT-PCR). The final EuO leaf ethanol extract powder was detected to contain caffeotannic acid at 58 mg/g and geniposide at 3.45 mg/g by high performance liquid chromatography (HPLC). EuO remarkably restrained cell oxidative damage and increased cell survival rate in a dose-dependent manner: 0 µg/ml, 0.21; 6.25 µg/ml, 0. 28; 12.5 µg/ml, 0.31; 25 µg/ml, 0.48; 50 µg/ml, 0.54; and 100 µg/ml, 0.66 (P<0.05), with the half-effective concentration being around 25 µg/ml. MTT results were confirmed by microscopic analysis. Western blotting and RT-PCR analyses showed that the expressions of caspases 3, 6, 7, and 9 were significantly decreased in the EuO-treated cells compared with the control (EuO- and H(2)O(2)-free) (P<0.05), with the half-effective concentration of EuO ranging from 12.5 to 25 µg/ml. We conclude that the ethanol-extracted EuO leaf extracts promoted the growth of MC3T3-E1 cells, and suppressed the H(2)O(2)-induced apoptosis in a rat MC3T3-E1 osteogenic cell model, likely due to the inhibition of caspases' activities. The results indicate that EuO is a potent antioxidant, which may contribute to its many cellular protective functions, including the promotion of bone growth. PMID:21194186

Lin, Jun; Fan, Yi-jing; Mehl, Christian; Zhu, Jia-jun; Chen, Hong; Jin, Ling-yan; Xu, Jing-hong; Wang, Hui-ming

2011-01-01

77

Apigenin and Quercetin Ameliorate Mitochondrial Alterations by Tunicamycin-Induced ER Stress in 3T3-L1 Adipocytes.  

PubMed

Endoplasmic reticulum (ER) is an important organelle with functions like protein synthesis, folding, and calcium homeostasis. ER stress, a condition that dramatically affects protein folding homeostasis in cells, has been associated with a number of metabolic disorders. Emerging clinical and preclinical evidence support the notion that pharmacological modulators of ER stress have therapeutic potential as a novel target for treating metabolic diseases. ER is in physical contact with mitochondria, and there is a strong cross talk between these organelles at functional level. The present investigation was aimed to check the mitochondrial alterations in adipocytes with tunicamycin-induced ER stress and modulation by apigenin and quercetin. For this, differentiated adipocytes were incubated with tunicamycin (2 ?g/ml) for 18 h, and changes in mitochondrial membrane potential, biogenesis, reactive oxygen species production, and adiponectin secretion were seen. Tunicamycin-induced ER stress altered reactive oxygen species (ROS) (6.34-fold?), membrane potential (4.1-fold?), mitochondrial biogenesis (2.4-fold?), and adiponectin secretion (3.5-fold?). Apigenin and quercetin ameliorated alterations in mitochondria. From results, we conclude that ER stress significantly alters mitochondrial functions and both the bioactives significantly protected mitochondrial alterations during ER stressand reestablished adiponectin secretion. PMID:25106896

Nisha, V M; Anusree, S S; Priyanka, A; Raghu, K G

2014-10-01

78

Expression of a splice variant of the receptor for GHRH in 3T3 fibroblasts activates cell proliferation responses to GHRH analogs  

Microsoft Academic Search

The stimulatory effects of growth hormone-releasing hormone (GHRH) and the antiproliferative action of GHRH antagonists have been demonstrated in various cancers, but the receptors that mediate these responses are not clearly identified. Recently, we reported that human cancer cell lines express splice variants (SVs) of the receptors for GHRH. SV1 exhibits the greatest similarity to the pituitary GHRH receptor and

Hippokratis Kiaris; Andrew V. Schally; Rebeca Busto; Gabor Halmos; Spyros Artavanis-Tsakonas; Jozsef L. Varga

2002-01-01

79

Cinnamon Extract Enhances Glucose Uptake in 3T3-L1 Adipocytes and C2C12 Myocytes by Inducing LKB1-AMP-Activated Protein Kinase Signaling  

PubMed Central

We previously demonstrated that cinnamon extract (CE) ameliorates type 1 diabetes induced by streptozotocin in rats through the up-regulation of glucose transporter 4 (GLUT4) translocation in both muscle and adipose tissues. This present study was aimed at clarifying the detailed mechanism(s) with which CE increases the glucose uptake in vivo and in cell culture systems using 3T3-L1 adipocytes and C2C12 myotubes in vitro. Specific inhibitors of key enzymes in insulin signaling and AMP-activated protein kinase (AMPK) signaling pathways, as well as small interference RNA, were used to examine the role of these kinases in the CE-induced glucose uptake. The results showed that CE stimulated the phosphorylation of AMPK and acetyl-CoA carboxylase. An AMPK inhibitor and LKB1 siRNA blocked the CE-induced glucose uptake. We also found for the first time that insulin suppressed AMPK activation in the adipocyte. To investigate the effect of CE on type 2 diabetes in vivo, we further performed oral glucose tolerance tests and insulin tolerance tests in type 2 diabetes model rats administered with CE. The CE improved glucose tolerance in oral glucose tolerance tests, but not insulin sensitivity in insulin tolerance test. In summary, these results indicate that CE ameliorates type 2 diabetes by inducing GLUT4 translocation via the AMPK signaling pathway. We also found insulin antagonistically regulates the activation of AMPK. PMID:24551069

Shen, Yan; Honma, Natsumi; Kobayashi, Katsuya; Jia, Liu Nan; Hosono, Takashi; Shindo, Kazutoshi; Ariga, Toyohiko; Seki, Taiichiro

2014-01-01

80

Farnesoid X Receptor Induces GLUT4 Expression Through FXR Response Element in the GLUT4 Promoter  

Microsoft Academic Search

GLUT4, the main insulin-responsive glucose transporter, plays a critical role in maintaining systemic glucose homeostasis and is subject to complicated metabolic regulation. GLUT4 expression disorder might cause insulin resistance, and over-expression of GLUT4 has been confirmed to ameliorate diabetes. Here, we reported that farnesoid X receptor (FXR) and its agonist chenodeoxycholic acid (CDCA) could induce GLUT4 transcription in 3T3-L1 and

Hong Shen; Yu Zhang; Hong Ding; Xu Wang; Lili Chen; Hualiang Jiang; Xu Shen

2008-01-01

81

SPARC is over-expressed in adipose tissues of diet-induced obese rats and causes insulin resistance in 3T3-L1 adipocytes.  

PubMed

Secreted protein acidic and rich in cysteine (SPARC) is a secretory multifunctional matricellular glycoprotein. High circulating levels of SPARC have been reported to be associated with obesity and insulin resistance. The aim of the present study was to investigate whether SPARC induces insulin resistance and mitochondrial dysfunction in adipocytes. Our results showed that feeding high fat diet to rats for 12 weeks significantly increased SPARC expression in adipose tissues at both mRNA and protein levels. Moreover, SPARC overexpression in stably transfected 3T3-L1 cells induced insulin resistance and mitochondrial dysfunction, as evidenced by inhibition of insulin-stimulated glucose transport, lower ATP synthesis and mitochondrial membrane potential, reduced expression of glucose transporter 4 (GLUT4), and increased levels of reactive oxygen species (ROS) in mature adipocytes. Finally, overexpression of SPARC also modulated the expression levels of several inflammatory cytokines, which play important roles in insulin resistance, glucose and lipid metabolism during adipogenesis. In conclusion, our data suggest that SPARC is involved in obesity-induced adipose insulin resistance and may serve as a potential target in the treatment of obesity and obesity-related insulin resistance. PMID:23910024

Shen, Yang; Zhao, Yuyan; Yuan, Lizhi; Yi, Wei; Zhao, Rui; Yi, Qianru; Yong, Tongwu

2014-01-01

82

Suppression of lipoprotein lipase in 3T3-L1 cells by a mediator produced by SEKI melanoma, a cachexia-inducing human melanoma cell line.  

PubMed

Production of a cachexia-inducing factor(s) by the SEKI melanoma cell line, established from a human melanoma, has been well documented. Conditioned medium from cultures of this melanoma cell line contains a factor(s) that inhibits the activity of lipoprotein lipase (LPL) in fully differentiated 3T3-L1 adipocytes. The mode of inhibition of this enzyme by the factor, i.e. its dose-dependency and time course, is very similar to that of LPL-inhibition by a macrophage-derived cachexia-inducing factor, cachectin/tumor necrosis factor (cachectin/TNF). However, the conditioned medium of SEKI melanoma cells does not contain any immuno-reactive substances reactive in enzyme-linked immunosorbent assay (ELISA) with anti-cachectin/TNF antibody, or with anti-interleukin 1 alpha or beta antibodies. This LPL-suppression factor present in the conditioned medium seems to be a peptide because of its heat-lability and apparent molecular weight of more than 25,000. The conditioned media from cultures of four other different cell lines were found to show no significant suppression of LPL activity. These results imply that SEKI melanoma cells produce a cachexia-inducing factor(s) similar to cachectin/TNF but that the molecule involved is different. PMID:2016276

Kawakami, M; Kondo, Y; Imai, Y; Hashiguchi, M; Ogawa, H; Hiragun, A; Aotsuka, S; Shibata, S; Oda, T; Murase, T

1991-01-01

83

Luteolin protects osteoblastic MC3T3-E1 cells from antimycin A-induced cytotoxicity through the improved mitochondrial function and activation of PI3K\\/Akt\\/CREB  

Microsoft Academic Search

Luteolin is a flavonoid found in many herbal extracts including celery, green pepper, parsley, perilla leaf and seeds, and chamomile. Antimycin A (AMA) is an inhibitor of the mitochondrial electron transport chain. In the present study, the protective effect of luteolin on AMA-induced cell damage was investigated in osteoblastic MC3T3-E1 cells. Luteolin significantly increased the viability of MC3T3-E1 cells in

Eun Mi Choi

84

A short pulse of mechanical force induces gene expression and growth in MC3T3-E1 osteoblasts via an ERK 1/2 pathway  

NASA Technical Reports Server (NTRS)

Physiological mechanical loading is crucial for maintenance of bone integrity and architecture. We have calculated the strain caused by gravity stress on osteoblasts and found that 4-30g corresponds to physiological levels of 40-300 microstrain. Short-term gravity loading (15 minutes) induced a 15-fold increase in expression of growth-related immediate early gene c-fos, a 5-fold increase in egr-1, and a 3-fold increase in autocrine bFGF. The non-growth-related genes EP-1, TGF-beta, and 18s were unaffected by gravity loading. Short-term physiological loading induced extracellular signal-regulated kinase (ERK 1/2) phosphorylation in a dose-dependent manner with maximum phosphorylation saturating at mechanical loading levels of 12g (p < 0.001) with no effect on total ERK. The phosphorylation of focal adhesion kinase (FAK) was unaffected by mechanical force. g-Loading did not activate P38 MAPK or c-jun N-terminal kinase (JNK). Additionally, a gravity pulse resulted in the localization of phosphorylated ERK 1/2 to the nucleus; this did not occur in unloaded cells. The induction of c-fos was inhibited 74% by the MEK1/2 inhibitor U0126 (p < 0.001) but was not affected by MEK1 or p38 MAPK-specific inhibitors. The long-term consequence of a single 15-minute gravity pulse was a 64% increase in cell growth (p < 0.001). U0126 significantly inhibited gravity-induced growth by 50% (p < 0.001). These studies suggest that short periods of physiological mechanical stress induce immediate early gene expression and growth in MC3T3-E1 osteoblasts primarily through an ERK 1/2-mediated pathway.

Hatton, Jason P.; Pooran, Milad; Li, Chai-Fei; Luzzio, Chris; Hughes-Fulford, Millie

2003-01-01

85

Simvastatin inhibits ox-LDL-induced inflammatory adipokines secretion via amelioration of ER stress in 3T3-L1 adipocyte.  

PubMed

Adipocytes behave as a rich source of pro-inflammatory cytokines including tumor necrosis factor-? (TNF-?) and monocyte chemoattractant protein 1 (MCP-1). Endoplasmic reticulum (ER) stress in adipocytes can alter adipokines secretion and induce inflammation. The aim of this study is to evaluate the effect of simvastatin on the ox-LDL-induced ER stress and expression and secretion of TNF-? and MCP-1 in 3T3-L1 adipocytes. Differentiated adipocytes were treated with various concentrations of ox-LDL (0-100 ?g/ml) for 24h with or without simvastatin pre-treatment. The protein expressions of ER stress markers, glucose-regulated protein 78 (GRP78) and C/EBP homology protein (CHOP), were determined by Western blot analysis. The mRNA expressions of TNF-? and MCP-1 were measured by real-time PCR. The protein release of TNF-? and MCP-1 in culture medium were evaluated by ELISA. Ox-LDL treatment led to significant up-regulation of GRP78 and CHOP in dose-dependent manner. The expressions of TNF-? and MCP-1 were dose-dependently increased at mRNA and protein levels after ox-LDL intervention. The effects of ox-LDL on adipocytes were abolished by pre-treatment with 4-phenylbutyrate (4-PBA), a chemical chaperone known to ameliorate ER stress. Simvastatin could inhibit ox-LDL-induced ER stress and reduce the expression of TNF-? and MCP-1 at mRNA and protien level in dose dependent manner. In conclusion, ox-LDL can stimulate the expression and secretion of TNF-? and MCP-1 through its activation of ER stress in adipocytes. Simvastatin might exert direct anti-inflammatory effects in adipocytes through amelioration of ER stress. PMID:23376721

Wu, Zhi-hong; Chen, Ya-qin; Zhao, Shui-ping

2013-03-01

86

3T3 fibroblasts induce cloned interleukin 3-dependent mouse mast cells to resemble connective tissue mast cells in granular constituency  

SciTech Connect

As assessed by ultrastructure, histochemical staining, and T-cell dependency, in vitro-differentiated interleukin 3-dependent mouse mast cells are comparable to the mast cells that reside in the gastrointestinal mucosa but not in the skin or the serosal cavity of the mouse. The authors now demonstrate that when cloned interleukin 3-dependent mast cells are cocultured with mouse skin-derived 3T3 fibroblasts in the presence of WEHI-3 conditioned medium for 28 days, the mast cells acquire the ability to stain with safranin, increase their histamine content approx. 50-fold and their carboxypeptidase. A content approx. 100-fold, and augment approx. their biosynthesis of proteoglycans bearing /sup 35/S-labeled haparin relative to /sup 35/S-labeled chondroitin sulfate glycosaminoglycans. Thus, fibroblasts induce interleukin 3-dependent mouse mast cells to change phenotype from mucosal-like to connective tissue-like, indicating that the biochemical and functional characteristics of this mast cell type are strongly influenced by the connective tissue microenvironment.

Dayton, E.T.; Pharr, P.; Ogawa, M.; Serafin, W.E.; Austen, K.F.; Levi-Schaffer, F.; Stevens, R.L.

1988-01-01

87

Bilobalide attenuates hypoxia induced oxidative stress, inflammation, and mitochondrial dysfunctions in 3T3-L1 adipocytes via its antioxidant potential.  

PubMed

Excessive expansion of white adipose tissue leads to hypoxia which is considered as a key factor responsible for adipose tissue dysfunction in obesity. Hypoxia induces inflammation, insulin resistance, and other obesity related complications. So the hypoxia-signalling pathway is expected to provide a new target for the treatment of obesity-associated complications. Inhibition or downregulation of the HIF-1 pathway could be an effective target for the treatment of obesity related hypoxia. In the present study, we evaluated the effect of hypoxia on functions of 3T3-L1 adipocytes emphasising on oxidative stress, antioxidant status, inflammation and mitochondrial functions. We have also evaluated the protective role of bilobalide, a bioactive from Gingko biloba, on hypoxia induced alterations. The results revealed that hypoxia significantly altered all the vital parameters of adipocyte biology like HIF-1? expression (103.47% ?), lactate and glycerol release (184.34% and 69.1% ?, respectively), reactive oxygen species (ROS) production (432.53% ?), lipid and protein oxidation (376.6% and 566.6% ?, respectively), reduction in antioxidant enzymes (superoxide dismutase and catalase) status, secretion of inflammatory markers (TNF-?, IL-6, IL-1? and IFN-?) and mitochondrial functions (mitochondrial mass, membrane potential, permeability transition pore integrity, superoxide generation). Bilobalide significantly protected adipocytes from adverse effects of hypoxia in a dose-dependent manner by attenuating oxidative stress, inflammation and protecting mitochondria. Acriflavine (HIF-1 inhibitor) was used as positive control. On the basis of this study, a detailed investigation is needed to delineate the mechanism of action of bilobalide to develop it as therapeutic target for obesity. PMID:25039303

Priyanka, A; Nisha, V M; Anusree, S S; Raghu, K G

2014-10-01

88

Imiquimod induces a Toll-like receptor 7-independent increase in intracellular calcium via IP(3) receptor activation.  

PubMed

Imiquimod is an itch-promoting, small, synthetic compound that is generally used to treat genital warts and basal cell carcinoma. The pruritogenic effect of imiquimod is considered to be due to TLR7 activation; however that idea has been challenged by our studies showing intact pruritogenic effects of imiquimod in TLR7 KO mice. Thus, the signaling pathways of imiquimod have not been completely elucidated. Here we investigated the novel effects of imiquimod on intracellular calcium ([Ca(2+)]i) signaling. We found that imiquimod induces [Ca(2+)]i increases in PC12 and F11 cells, and even in NIH-3T3 and HEK293T cells, which do not express TLR7. This [Ca(2+)]i increase was due to Ca(2+) release from the internal store without extracellular Ca(2+) influx. Neither FCCP, a mitochondrial Ca(2+) reuptake inhibitor, nor dantrolene, a ryanodine receptor inhibitor, affected the imiquimod-induced [Ca(2+)]i increase. However, 2APB, an IP3 receptor blocker, inhibited the imiquimod-induced [Ca(2+)]i increase. U73122, a PLC? inhibitor, failed to block the imiquimod-induced [Ca(2+)]i increase. These data indicate that imiquimod triggers IP3 receptor-dependent Ca(2+) signaling independently of TLR7. PMID:24971541

Hwang, Heehong; Min, Hyunjung; Kim, Donghoon; Yu, Seong-Woon; Jung, Sung Jun; Choi, Se-Young; Lee, Sung Joong

2014-07-18

89

Ultraviolet C Irradiation Induces Different Expression of Cyclooxygenase 2 in NIH 3T3 Cells and A431 Cells: The Roles of COX-2 Are Different in Various Cell Lines  

E-print Network

caused cell growth inhibition and induced cell death after exposure for 24–36 h. The growth of NIH 3T3 cells was significantly suppressed at 24 h after UVC irradiation whereas the proliferation of A431 cells was inhibited until 36 h after UVC irradiation. UVC irradiation increased COX-2 expression and such up-regulation reached a maximum during 3–6 h in NIH 3T3 cells. In contrast, UVC-induced COX-2 reached a maximum after 24–36 h in A431 cells. Measuring prostaglandin E2 (PGE2) level showed a biphasic profile that PGE2 release was rapidly elevated in 1–12 h after UVC irradiation and increased again at 24 h in both cell lines. Treatment with the selective COX-2 inhibitor, SC-791, during maximum expression of COX-2 induction, attenuated the UVC induced-growth inhibition in NIH 3T3 cells. In contrast, SC-791 treatment after UVC irradiation enhanced death of A431 cells. These data showed that the patterns of UVC-induced PGE2 secretion from NIH 3T3 cells and A431 cells were similar despite the differential profile in UVC-induced COX-2 up-regulation.

Ming-hong Tai; Chien-hui Weng; Dir-pu Mon; Chun-yi Hu; Ming-hsiu Wu

2012-01-01

90

Thyroid hormone (T3)-induced up-regulation of voltage-activated sodium current in cultured postnatal hippocampal neurons requires secretion of soluble factors from glial cells.  

PubMed

We have previously shown that treatment with the thyroid hormone T(3) increases the voltage-gated Na(+)current density (Nav-D) in hippocampal neurons from postnatal rats, leading to accelerated action potential upstrokes and increased firing frequencies. Here we show that the Na(+) current regulation depends on the presence of glial cells, which secrete a heat-instable soluble factor upon stimulation with T(3). The effect of conditioned medium from T(3)-treated glial cells was mimicked by basic fibroblast growth factor (bFGF), known to be released from cerebellar glial cells after T(3) treatment. Neutralization assays of astrocyte-conditioned media with anti-bFGF antibody inhibited the regulation of the Nav-D by T(3). This suggests that the up-regulation of the neuronal sodium current density by T(3) is not a direct effect but involves bFGF release and satellite cells. Thus glial cells can modulate neuronal excitability via secretion of paracrinely acting factors. PMID:19460859

Niederkinkhaus, Vanessa; Marx, Romy; Hoffmann, Gerd; Dietzel, Irmgard D

2009-09-01

91

Extracellular calcium-sensing-receptor (CaR)-mediated opening of an outward K(+) channel in murine MC3T3-E1 osteoblastic cells: evidence for expression of a functional CaR  

NASA Technical Reports Server (NTRS)

The existence in osteoblasts of the G-protein-coupled extracellular calcium (Ca(o)(2+))-sensing receptor (CaR) that was originally cloned from parathyroid and kidney remains controversial. In our recent studies, we utilized multiple detection methods to demonstrate the expression of CaR transcripts and protein in several osteoblastic cell lines, including murine MC3T3-E1 cells. Although we and others have shown that high Ca(o)(2+) and other polycationic CaR agonists modulate the function of MC3T3-E1 cells, none of these actions has been unequivocally shown to be mediated by the CaR. Previous investigations using neurons and lens epithelial cells have shown that activation of the CaR stimulates Ca(2+)-activated K(+) channels. Because osteoblastic cells express a similar type of channel, we have examined the effects of specific "calcimimetic" CaR activators on the activity of a Ca(2+)-activated K(+) channel in MC3T3-E1 cells as a way of showing that the CaR is not only expressed in those cells but is functionally active. Patch-clamp analysis in the cell-attached mode showed that raising Ca(o)(2+) from 0.75 to 2.75 mmol/L elicited about a fourfold increase in the open state probability (P(o)) of an outward K(+) channel with a conductance of approximately 92 pS. The selective calcimimetic CaR activator, NPS R-467 (0.5 micromol/L), evoked a similar activation of the channel, while its less active stereoisomer, NPSS-467 (0.5 micromol/L), did not. Thus, the CaR is not only expressed in MC3T3-E1 cells, but is also functionally coupled to the activity of a Ca(2+)-activated K(+) channel. This receptor, therefore, could transduce local or systemic changes in Ca(o)(2+) into changes in the activity of this ion channel and related physiological processes in these and perhaps other osteoblastic cells.

Ye, C. P.; Yamaguchi, T.; Chattopadhyay, N.; Sanders, J. L.; Vassilev, P. M.; Brown, E. M.; O'Malley, B. W. (Principal Investigator)

2000-01-01

92

ZnT-1, ZnT-3, CaMK II, PRG-1 expressions in hippocampus following neonatal seizure-induced cognitive deficit in rats.  

PubMed

Epilepsy in children is associated with a broad spectrum of cognitive deficits, which is associated with hippocampal mossy fiber sprouting. The underlying molecular mechanisms involved in mossy fiber sprouting in hippocampus following developmental seizures are not completely known. We studied the timing of cognitive dysfunction following neonatal seizures and the relation of this cognitive impairment to zinc transporter 1 (ZnT-1), 3 (ZnT-3), calcium/calmodulin-dependent protein kinase II (CaMK II), plasticity-related gene 1 (PRG-1) expression in hippocampus. A seizure was induced by inhalant flurothyl daily in neonatal Sprague-Dawley rats from postnatal day 6 (P6). Rats were assigned into the single-seizure group (SS), the recurrent-seizure group (RS, seizures induced in six consecutive days), and the control group. During P41-P46 and P85-P90, the rats were tested for spatial learning and memory abilities with automatic Morris water maze task. At P90, mossy fiber sprouting and gene expression in hippocampus were determined subsequently by Timm staining and RT-PCR methods. The escape latencies from the water maze were significantly longer in rats of RS group than those of the control and SS groups at d4 of the first maze test and at d3, d4 of the second maze test. As far as Spatial Probe Test was concerned, the frequency of passing through the platform quadrant was significantly decreased in RS group than that in control and SS groups in the entire two probe tests. In rats with recurrent seizures (RS group), there was an increased distribution of Timm granules in both the supragranular region of the dentate gyrus and the stratum pyramidale of CA3 subfield in RS group, while remaining barely visible in control and SS groups; the Timm scores in CA3 and dentate gyrus in the RS animals were significantly higher than that in the control and SS groups. RT-PCR densitometry analysis showed that the ratios of hippocampal ZnT-1 to beta-actin of SS and RS group were decreased significantly compared with that of control group. Meanwhile, CaMK II to beta-actin of RS group was markedly lower compared with those of SS and control groups. Our results suggest that the long-term adverse effects of recurrent neonatal seizures on cognition and mossy fiber sprouting may be associated with the down-regulated expression of ZnT-1 and CaMK II in hippocampus. PMID:19059322

Ni, Hong; Jiang, Yu-Wu; Tao, Lu-Yang; Jin, Mei-Fang; Wu, Xi-Ru

2009-02-10

93

Inhibition of Calcium-Independent Phospholipases A2beta or A2gamma Inhibit Hormone-Induced Differentiation of 3T3-L1 Preadipocytes.  

National Technical Information Service (NTIS)

A method for identifying an agonist exhibiting molecular or pharmacologic inhibition which is effective against the activity of at least one of iPLA(sub 2)beta and iPLA(sub 2)gamma which comprises culturing 3T3-L1 cells and transfecting them with negative...

R. W. Gross

2004-01-01

94

Estradiol-induced estrogen receptor-? trafficking  

PubMed Central

Estradiol has rapid actions in the central nervous system, which are mediated by membrane estrogen receptors (ERs) and activate cell signaling pathways through interaction with metabotropic glutamate receptors (mGluRs). Membrane-initiated estradiol signaling increases the free cytoplasmic calcium concentration ([Ca2+]i) that stimulates the synthesis of neuroprogesterone in astrocytes. We used surface biotinylation to demonstrate that ER? has an extracellular portion. In addition to the full length ER? (apparent M.W. 66 kDa), surface biotinylation labeled an ER?-immunoreactive protein (M.W. ~ 52 kDa) identified by both COOH- and NH2-directed antibodies. Estradiol treatment regulated membrane levels of both proteins in parallel: within 5 min, estradiol significantly increased membrane levels of the 66 kDa and 52 kDa ER?. Internalization, a measure of membrane receptor activation, was also increased by estradiol with a similar time course. Continuous treatment with estradiol for 24–48 hr reduced ER? levels, suggesting receptor down-regulation. Estradiol also increased mGluR1a trafficking and internalization, consistent with the proposed ER?-mGluR1a interaction. Blocking ER with ICI 182,780 or mGluR1a with LY 367385 prevented ER? trafficking to and from the membrane. Estradiol-induced [Ca2+]i flux was also significantly increased at the time of peak ER? activation/internalization. These results demonstrate that ER? is present in the membrane and has an extracellular portion. Furthermore, membrane levels and internalization of ER? are regulated by estradiol and mGluR1a ligands. The pattern of trafficking into and out of the membrane suggests that the changing concentration of estradiol during the estrous cycle regulates ER? to augment and then terminate membrane-initiated signaling. PMID:19955385

Bondar, Galyna; Kuo, John; Hamid, Naheed; Micevych, Paul

2010-01-01

95

3T3-L1 adipocytes induce dysfunction of MIN6 insulin-secreting cells via multiple pathways mediated by secretory factors in a co-culture system.  

PubMed

Pancreatic beta-cell dysfunction is an important pathological change in type 2 diabetes, which is tightly related to obesity. However, the direct role of adipose tissue in beta-cell dysfunction has not been well understood. In this study, we examined the effects of 3T3-L1 adipocytes on MIN6 insulin-secreting cells in a co-culture system. MIN6 cells used here kept most of beta-cell functions but less sensitive to glucose stimulation. Tolbutamide, the KATP channel blocker, was therefore used to stimulate insulin secretion in this report. MIN6 cells co-cultured with 3T3-L1 adipocytes had significantly reduced intracellular calcium concentration ([Ca2+]i) and lost the ability to secrete insulin in response to tolbutamide, compared to the control cells. 3T3-L1 adipocytes significantly decreased the expression of insulin, glucokinase and Kir6.2 genes but increased the expression of uncoupling protein-2 (UCP-2) in MIN6 cells after one week of co-culture, as measured by semi-quantitative RT-PCR. 3T3-L1 adipocyte-conditioned medium also significantly decreased insulin secretion and the expression of insulin, glucokinase and Kir6.2 genes in MIN6 cells. The conditioned medium also reduced tyrosine kinase activity in MIN6 cells. The inhibitor of protein tyrosine kinase, genistein, decreased the expression of glucokinase and Kir6.2 in MIN6 cells, while two free fatty acids, oleic acid and linoleic acids, were found to increase UCP-2 expression. The present study demonstrates that 3T3-L1 adipocytes directly impair insulin secretion and the expression of important genes in MIN6 cells. The effects of T3-L1 adipocytes on MIN6 cells are ascribed to secreted bioactive factors and may be mediated via multiple pathways, which include the upregulation of UCP-2 expression via free fatty acids, and downregulation of glucokinase and Kir6.2 expression via decreasing protein tyrosine kinase activity. PMID:17709898

Zhao, Yu-Feng; Feng, Dan-Dan; Hernandez, Maria; Chen, Chen

2007-02-01

96

Insulin-Mimetic Action of Rhoifolin and Cosmosiin Isolated from Citrus grandis (L.) Osbeck Leaves: Enhanced Adiponectin Secretion and Insulin Receptor Phosphorylation in 3T3-L1 Cells  

PubMed Central

Citrus grandis (L.) Osbeck (red wendun) leaves have been used in traditional Chinese medicine to treat several illnesses including diabetes. However, there is no scientific evidence supporting these actions and its active compounds. Two flavone glycosides, rhoifolin and cosmosiin were isolated for the first time from red wendun leaves and, identified these leaves are rich source for rhoifolin (1.1%, w/w). In differentiated 3T3-L1 adipocytes, rhoifolin and cosmosiin showed dose-dependent response in concentration range of o.oo1–5??M and 1–20??M, respectively, in biological studies beneficial to diabetes. Particularly, rhoifolin and cosmosiin at 0.5 and 20??M, respectively showed nearly similar response to that 10?nM of insulin, on adiponectin secretion level. Furthermore, 5??M of rhoifolin and 20??M of cosmosiin showed equal potential with 10?nM of insulin to increase the phosphorylation of insulin receptor-?, in addition to their positive effect on GLUT4 translocation. These findings indicate that rhoifolin and cosmosiin from red wendun leaves may be beneficial for diabetic complications through their enhanced adiponectin secretion, tyrosine phosphorylation of insulin receptor-? and GLUT4 translocation. PMID:20008903

Rao, Yerra Koteswara; Lee, Meng-Jen; Chen, Keru; Lee, Yi-Ching; Wu, Wen-Shi; Tzeng, Yew-Min

2011-01-01

97

PPAR-Activating Angiotensin Type1 Receptor Blockers Induce Adiponectin  

Microsoft Academic Search

The adipose-specific protein adiponectin has been recently discovered to improve insulin sensitivity. Angiotensin type-1 receptor (AT1R) blockers (ARBs) reduce the incidence of type 2 diabetes mellitus by mostly unknown molecular mechanisms. To identify new antidiabetic mechanisms of ARBs, we studied the regulation of adiponectin by angiotensin II (Ang II) and different ARBs in murine 3T3-L1 adipocytes and obese Zucker rats.

Ronald Clasen; Michael Schupp; Anna Foryst-Ludwig; Christiane Sprang; Markus Clemenz; Maxim Krikov; Christa Thone-Reineke; Thomas Unger; Ulrich Kintscher

2005-01-01

98

Multiple opioid receptors mediate the hypotensive response induced by central 5HT 3 receptor stimulation  

Microsoft Academic Search

The aim of the present work was to investigate the role of brain ?, ? and ? opioid receptors in the central serotonergic mechanisms regulating blood pressure in rats. The data obtained show that: (1) pharmacological activation of central 5-HT3 receptors yields a significant decrease in blood pressure; (2) the blockade of those receptors by a selective antagonist induces an

J. B. Fregoneze; E. F. Oliveira; V. F. Ribeiro; H. S. Ferreira; E. De Castro e Silva

2011-01-01

99

Effect of quinupristin/dalfopristin on 3T3 and Eahy926 cells in vitro in comparison to other antimicrobial agents with the potential to induce infusion phlebitis.  

PubMed

Infusion phlebitis is a common clinical problem that is observed with some antimicrobial agents, when being administered intravenously. In this study, cultured murine fibroblasts and immortalised human endothelial cells were exposed to three antibiotics at clinically relevant concentrations to assess their toxic potential in two established cytotoxicity assays. BALB/c 3T3 fibroblasts and Eahy926 endothelial cells were exposed to quinupristin/dalfopristin (QD), erythromycin and levofloxacin at increasing concentrations. For assessment of cytotoxicity the cells were incubated with neutral red (NR) or stained with crystal violet (CV). Measurements were done by photometry. At the concentration range tested QD and erythromycin showed a concentration-dependent cytotoxic effect in both cell cultures. In 3T3 cells the half-maximal effect concentration (EC50) was 20 mg/l for QD and 340 mg/l for erythromycin in the NR uptake test and 12 and 200 mg/l, respectively, in the CV assay. In Eahy926 cells the EC50 was 50 mg/l for QD and 880 mg/l for erythromycin in the NR uptake test and 40 and 750 mg/l, respectively, in the CV assay. No EC50 could be established in both cell types for levofloxacin. Eahy926 cells were less sensitive to cytotoxic stimuli than 3T3 fibroblasts. Cytotoxic effects in both cell cultures occurred in the following order: QD > erythromycin > levofloxacin. This ranking correlates well with the frequency of local adverse effects observed with the infusion of these antibiotics in patients. Thus, these in vitro assays may serve as an estimate for the prediction of local tolerability of antibiotics when administered parenterally. PMID:17119926

Kruse, Matthias; Kilic, Bülent; Flick, Burkhard; Stahlmann, Ralf

2007-06-01

100

Phorbol esters and diacylglycerol inhibit vasopressin-induced increases in cytoplasmic-free Ca2+ and 45Ca2+ efflux in Swiss 3T3 cells.  

PubMed

Vasopressin increased intracellular free calcium concentration [Ca2+]i in quin-2-loaded quiescent Swiss 3T3 cells. This effect of vasopressin was rapidly inhibited by biologically active tumour promoters including phorbol dibutyrate (PBt2) and by the synthetic diacylglycerol 1-oleoyl-2-acetyl-glycerol (OAG). Prolonged pretreatment of Swiss 3T3 cells with PBt2 causes a loss of protein kinase C activity (Rodriguez-Pena & Rozengurt, Biochem biophys res commun 120 (1984) 1053) [28]. This pretreatment abolished the inhibition by PBt2 or OAG of vasopressin-mediated increases in [Ca2+]i. Vasopressin also stimulated 45Ca2+ efflux from cells pre-loaded with the isotope. This effect of the hormone was also inhibited by PBt2. Prolonged pretreatment with PBt2 prevented the inhibition of vasopressin-stimulated 45Ca2+ release by PBt2. Thus, protein kinase C stimulation inhibits vasopressin-mediated increases in [Ca2+]i and 45Ca2+ efflux apparently by blocking the increased release of Ca2+ from an intracellular store caused by the hormone. These findings suggest that activation of protein kinase C may act as a feedback inhibitor to modulate ligand-mediated increases in [Ca2+]i. PMID:3458589

Mendoza, S A; Lopez-Rivas, A; Sinnett-Smith, J W; Rozengurt, E

1986-06-01

101

Multiple opioid receptors mediate the hypotensive response induced by central 5-HT(3) receptor stimulation.  

PubMed

The aim of the present work was to investigate the role of brain ?, ? and ? opioid receptors in the central serotonergic mechanisms regulating blood pressure in rats. The data obtained show that: (1) pharmacological activation of central 5-HT(3) receptors yields a significant decrease in blood pressure; (2) the blockade of those receptors by a selective antagonist induces an acute hypertensive response; (3) the pharmacological blockade of central opioid receptors by three different opioid antagonists exhibiting variable degrees of selectivity to ?, ? and ? opioid receptors always suppressed the hypotensive response induced by central 5-HT(3) receptor stimulation; (4) the blockade of opioid receptors by the same opioid antagonists that impaired the hypotensive effect of central 5-HT(3) receptor stimulation failed to modify blood pressure in animals not submitted to pharmacological manipulations of central 5-HT(3) receptor function. It is shown that a 5-HT(3) receptor-dependent mechanism seems to be part of the brain serotonergic system that contributes to cardiovascular regulation since the hypertensive response observed after ondansetron administration indicates that central 5-HT(3) receptors exert a tonic inhibitory drive on blood pressure. Furthermore, the data obtained here clearly indicate that the hypotensive response observed after pharmacological stimulation of central 5-HT(3) receptors depends on the functional integrity of brain ?, ? and ? opioid receptors, suggesting that a functional interaction between serotonergic and opiatergic pathways in the brain is part of the complex, multifactorial system that regulates blood pressure in the central nervous system. PMID:21514668

Fregoneze, J B; Oliveira, E F; Ribeiro, V F; Ferreira, H S; De Castro E Silva, E

2011-06-01

102

DNA microarray analyses of genes expressed differentially in 3T3-L1 adipocytes co-cultured with murine macrophage cell line RAW264.7 in the presence of the toll-like receptor 4 ligand bacterial endotoxin.  

PubMed

Recent studies have suggested that macrophages were integrated into adipose tissues to interact with adipocytes, thereby exacerbating inflammatory responses. Furthermore, both adipocytes and macrophages appear to express toll-like receptor-4 (TLR-4), and free fatty acids may stimulate cells through TLR-4. Herein, we analyzed genes differentially expressed in adipocytes when co-cultured with macrophages in the presence of a ligand for TLR-4, bacterial lipopolysaccharide (LPS). RAW264.7, a murine macrophage cell line and differentiated 3T3-L1 adipocytes were co-cultured using a transwell system. Genes differentially expressed in adipocytes were analyzed by the DNA microarray method following 4, 8, 12 and 24 h stimulation with 1 ng ml(-1) of Escherichia coli LPS. Randomly selected genes with high expressions were confirmed by quantitative methods at both the gene and the protein level. Co-culture of macrophages and adipocytes with a low LPS concentration (1 ng ml(-1)) markedly upregulated gene expressions associated with inflammation and/or angiogenesis, such as those of interleukin-6 (IL-6), MCP-1, RANTES and CXCL1/KC, in adipocytes. Furthermore, several genes associated with insulin resistance were differentially expressed. Upregulations of genes encoding MCP-1, RANTES and CXC/KC were confirmed by quantitative methods. These results suggest that ligands for TLR-4 stimulate both adipocytes and macrophages to upregulate the expressions of many genes associated with inflammation and/or angiogenesis. PMID:18779827

Yamashita, A; Soga, Y; Iwamoto, Y; Asano, T; Li, Y; Abiko, Y; Nishimura, F

2008-11-01

103

Trans-cinnamic acid increases adiponectin and the phosphorylation of AMP-activated protein kinase through G-protein-coupled receptor signaling in 3T3-L1 adipocytes.  

PubMed

Adiponectin and intracellular 5'adenosine monophosphate-activated protein kinase (AMPK) are important modulators of glucose and fat metabolism. Cinnamon exerts beneficial effects by improving insulin sensitivity and blood lipids, e.g., through increasing adiponectin concentrations and AMPK activation. The underlying mechanism is unknown. The Gi/Go-protein-coupled receptor (GPR) 109A stimulates adiponectin secretion after binding its ligand niacin. Trans-cinnamic acid (tCA), a compound of cinnamon is another ligand. We hypothesize whether AMPK activation and adiponectin secretion by tCA is transmitted by GPR signaling. Differentiated 3T3-L1 cells were incubated with pertussis toxin (PTX), an inhibitor of G(i)/G(o)-protein-coupling, and treated with different tCA concentrations. Treatment with tCA increased adiponectin and the pAMPK/AMPK ratio (p ? 0.001). PTX incubation abolished the increased pAMPK/AMPK ratio and adiponectin secretion. The latter remained increased compared to controls (p ? 0.002). tCA treatment stimulated adiponectin secretion and AMPK activation; the inhibitory effect of PTX suggests GPR is involved in tCA stimulated signaling. PMID:24557583

Kopp, Christina; Singh, Shiva P; Regenhard, Petra; Müller, Ute; Sauerwein, Helga; Mielenz, Manfred

2014-01-01

104

Morphological transformation induced by multiwall carbon nanotubes on Balb/3T3 cell model as an in vitro end point of carcinogenic potential.  

PubMed

In this work we investigated the toxicological effects of nude and chemically functionalised (-NH(2), -OH and -COOH groups) multiwall carbon nanotubes (mwCNTs) using immortalised mouse fibroblasts cell line (Balb/3T3) as in vitro model, alternative to the use of animals, to assess basal cytotoxicity, carcinogenic potential, genotoxicity and cell interaction of nanomaterials (NM). Combining in vitro tests such as cell transformation assay and micronucleus with physicochemical and topological analysis, we obtained results showing no cytotoxicity and genotoxicity. Carcinogenic potential and mwCNTs interaction with cells were instead evident. We stressed the importance that different toxicological end points have to be considered when studying NM, therefore, assays able to detect long-term effects, such as carcinogenicity, must be taken into account together with a panel of tests able to detect more immediate effects like basal cytotoxicity or genotoxicity. PMID:22279961

Ponti, Jessica; Broggi, Francesca; Mariani, Valentina; De Marzi, Laura; Colognato, Renato; Marmorato, Patrick; Gioria, Sabrina; Gilliland, Douglas; Pascual Garcěa, César; Meschini, Stefania; Stringaro, Annarita; Molinari, Agnese; Rauscher, Hubert; Rossi, François

2013-03-01

105

Conformational changes of human beta 1 thyroid hormone receptor induced by binding of 3,3',5-triiodo-L-thyronine.  

PubMed

To understand the structural basis in the hormone-dependent transcriptional regulation of human beta 1 thyroid hormone receptor (h-TR beta 1), we studied the conformational changes of h-TR beta 1 induced by binding of 3,3',5-triiodo-L-thyronine (T3). h-TR beta 1 was treated with trypsin alone or in the presence of T3, thyroid hormone response element (TRE) or T3 together with TREs. Without T3, h-TR beta 1 was completely digested by trypsin. Binding of TREs had no effect on the tryptic digestion pattern. However, T3-bound h-TR beta 1 became resistant to tryptic digestion and yielded trypsin-resistant peptide fragments with molecular weight of 28,000 and 24,000. Chymotryptic digestion also yielded a T3-protected 24 Kd peptide fragment. Using anti-h-TR beta 1 antibodies and amino acid sequencing, the 28 Kd fragment was identified to be Ser202-Asp456. The 24 Kd tryptic fragments were found to be Lys239-Asp456 and Phe240-Asp456. The 24 Kd chymotryptic fragment was identified to be Lys235-Asp456. The structural changes as a result of T3 binding could serve as a transducing signal to modulate the gene regulating activity of h-TR beta 1. PMID:8363616

Bhat, M K; Parkison, C; McPhie, P; Liang, C M; Cheng, S Y

1993-08-31

106

Molecular mechanism of 9-cis-retinoic acid inhibition of adipogenesis in 3T3-L1 cells  

SciTech Connect

Highlights: ? We examined the effects of 9-cis-RA on adipogenesis in mouse preadipocyte 3T3-L1. ? 9-cis-RA inhibited lipid accumulation in adipogenetically-induced 3T3-L1 cells. ? A RXR pan-antagonist suppressed the inhibitory effects of 9-cis-RA on adipogenesis. ? This antagonist had no effects on RXR? and PPAR? levels in 9-cis-RA-treated cells. ? 9-cis-RA-induced decrease in both RXR? and PPAR? was independent of RXR activation. -- Abstract: Retinoic acid (RA) signaling is mediated by specific nuclear hormone receptors. Here we examined the effects of 9-cis-RA on adipogenesis in mouse preadipocyte 3T3-L1 cells. 9-cis-RA inhibits the lipid accumulation of adipogenetically induced 3T3-L1 cells. The complex of retinoid X receptor ? (RXR?) with peroxisome proliferator-activated receptor ? (PPAR?) is a major transcription factor in the process of adipogenesis, and the levels of these molecules were decreased by 9-cis-RA treatment. A RXR pan-antagonist suppressed 9-cis-RA’s inhibitory effects on adipogenesis, but not on the intracellular levels of both RXR? and PPAR?. These results suggest that 9-cis-RA could inhibit adipogenesis by activating RXR, and decrease both RXR and PPAR?s levels in a RXR activation-independent manner.

Sagara, Chiaki; Takahashi, Katsuhiko [Laboratory of Physiological Chemistry, Institute of Medicinal Chemistry, Hoshi University, Shinagawa, Tokyo 142-8501 (Japan)] [Laboratory of Physiological Chemistry, Institute of Medicinal Chemistry, Hoshi University, Shinagawa, Tokyo 142-8501 (Japan); Kagechika, Hiroyuki [School of Biomedical Science, Institute of Biomaterials and Bioengineering, Tokyo Medical and Dental University, Chiyoda, Tokyo 101-0062 (Japan)] [School of Biomedical Science, Institute of Biomaterials and Bioengineering, Tokyo Medical and Dental University, Chiyoda, Tokyo 101-0062 (Japan); Takahashi, Noriko, E-mail: t-noriko@hoshi.ac.jp [Laboratory of Physiological Chemistry, Institute of Medicinal Chemistry, Hoshi University, Shinagawa, Tokyo 142-8501 (Japan)] [Laboratory of Physiological Chemistry, Institute of Medicinal Chemistry, Hoshi University, Shinagawa, Tokyo 142-8501 (Japan)

2013-03-29

107

Endoplasmic reticulum stress suppresses lipin-1 expression in 3T3-L1 adipocytes  

SciTech Connect

Highlights: ? Lipin-1 involves lipid metabolism, adipocyte differentiation, and inflammation. ? Adipose lipin-1 expression is reduced in obesity. ? ER stress suppresses lipin-1 expression in 3T3-L1 adipocytes. ? Activation of PPAR-? recovers ER stress-induced lipin-1 reduction. -- Abstract: Lipin-1 plays crucial roles in the regulation of lipid metabolism and cell differentiation in adipocytes. In obesity, adipose lipin-1 mRNA expression is decreased and positively correlated with systemic insulin sensitivity. Amelioration of the lipin-1 depletion might be improved dysmetabolism. Although some cytokines such as TNF-? and interleukin-1? reduces adipose lipin-1 expression, the mechanism of decreased adipose lipin-1 expression in obesity remains unclear. Recently, endoplasmic reticulum (ER) stress is implicated in the pathogenesis of obesity. Here we investigated the role of ER stress on the lipin-1 expression in 3T3-L1 adipocytes. We demonstrated that lipin-1 expression was suppressed by the treatment with ER stress inducers (tunicamycin and thapsigargin) at transcriptional level. We also showed that constitutive lipin-1 expression could be maintained by peroxisome proliferator-activated receptor-? in 3T3-L1 adipocytes. Activation of peroxisome proliferator-activated receptor-? recovered the ER stress-induced lipin-1 suppression. These results suggested that ER stress might be involved in the pathogenesis of obesity through lipin-1 depletion.

Takahashi, Nobuhiko, E-mail: ntkhs@hoku-iryo-u.ac.jp [Department of Internal Medicine, School of Dentistry, Health Sciences University of Hokkaido, 1757, Kanazawa, Ishikari-Toubetsu, Hokkaido 061-0023 (Japan) [Department of Internal Medicine, School of Dentistry, Health Sciences University of Hokkaido, 1757, Kanazawa, Ishikari-Toubetsu, Hokkaido 061-0023 (Japan); Division of Gastroenterology and Hematology/Oncology, Department of Medicine, Asahikawa Medical University, 2-1-1-1, Midorigaoka-Higashi, Asahikawa, Hokkaido 078-8510 (Japan); Yoshizaki, Takayuki [Innovation Center, Kagoshima University, 1-21-40, Korimoto, Kagoshima 890-0065 (Japan)] [Innovation Center, Kagoshima University, 1-21-40, Korimoto, Kagoshima 890-0065 (Japan); Hiranaka, Natsumi; Suzuki, Takeshi [Department of Internal Medicine, School of Dentistry, Health Sciences University of Hokkaido, 1757, Kanazawa, Ishikari-Toubetsu, Hokkaido 061-0023 (Japan)] [Department of Internal Medicine, School of Dentistry, Health Sciences University of Hokkaido, 1757, Kanazawa, Ishikari-Toubetsu, Hokkaido 061-0023 (Japan); Yui, Tomoo; Akanuma, Masayoshi [Department of Fixed Prosthodontics and Oral Implantology, School of Dentistry, Health Sciences University of Hokkaido, 1757, Kanazawa, Ishikari-Toubetsu, Hokkaido 061-0023 (Japan)] [Department of Fixed Prosthodontics and Oral Implantology, School of Dentistry, Health Sciences University of Hokkaido, 1757, Kanazawa, Ishikari-Toubetsu, Hokkaido 061-0023 (Japan); Kanazawa, Kaoru [Department of Dental Anesthesiology, School of Dentistry, Health Sciences University of Hokkaido, 1757, Kanazawa, Ishikari-Toubetsu, Hokkaido 061-0023 (Japan)] [Department of Dental Anesthesiology, School of Dentistry, Health Sciences University of Hokkaido, 1757, Kanazawa, Ishikari-Toubetsu, Hokkaido 061-0023 (Japan); Yoshida, Mika; Naito, Sumiyoshi [Department of Clinical Laboratory, Health Sciences University of Hokkaido, 1757, Kanazawa, Ishikari-Toubetsu, Hokkaido 061-0023 (Japan)] [Department of Clinical Laboratory, Health Sciences University of Hokkaido, 1757, Kanazawa, Ishikari-Toubetsu, Hokkaido 061-0023 (Japan); Fujiya, Mikihiro; Kohgo, Yutaka [Division of Gastroenterology and Hematology/Oncology, Department of Medicine, Asahikawa Medical University, 2-1-1-1, Midorigaoka-Higashi, Asahikawa, Hokkaido 078-8510 (Japan)] [Division of Gastroenterology and Hematology/Oncology, Department of Medicine, Asahikawa Medical University, 2-1-1-1, Midorigaoka-Higashi, Asahikawa, Hokkaido 078-8510 (Japan); Ieko, Masahiro [Department of Internal Medicine, School of Dentistry, Health Sciences University of Hokkaido, 1757, Kanazawa, Ishikari-Toubetsu, Hokkaido 061-0023 (Japan)] [Department of Internal Medicine, School of Dentistry, Health Sciences University of Hokkaido, 1757, Kanazawa, Ishikari-Toubetsu, Hokkaido 061-0023 (Japan)

2013-02-01

108

Diperoxovanadate can substitute for H 2O 2 at much lower concentration in inducing features of premature cellular senescence in mouse fibroblasts (NIH3T3)  

Microsoft Academic Search

Stress induced premature senescence (SIPS) in mammalian cells is an accelerated ageing response and experimentally obtained on treatment of cells with high concentrations of H2O2, albeit at sub-lethal doses, because H2O2 gets depleted by abundant cellular catalase. In the present study diperoxovanadate (DPV) was used as it is known to be stable at physiological pH, to be catalase-resistant and to

Nirupama Chatterjee; Shashi Kiran; Babul Moni Ram; Nashreen Islam; Tangirala Ramasarma; Gayatri Ramakrishna

2011-01-01

109

PACAP up-regulates the expression of apolipoprotein D in 3T3-L1 adipocytes. DRG/3T3-L1 co-cultures study.  

PubMed

The existence of a cross-talk between nerves and fatty tissue is increasingly recognized. Using co-cultures of dorsal root ganglion (DRG)-derived cells and 3T3-L1 adipocytes, we have previously shown that the presence of fat cells enhances neurite outgrowth and number of synapses. Vice versa, neural cells induced expression of neurotrophic adipokines apolipoprotein D and E (ApoD, ApoE) and angiopoietin-1 (Ang-1) by adipocytes. Here, we tested whether pituitary adenylate cyclase-activating peptide (PACAP), which is released by sensory fibres and causes Ca(2+) influx into fat cells, is involved in ApoD induction. Using 3T3-L1 cell cultures, we found that PACAP at a dose of 1 nM up-regulated the expression of ApoD protein and mRNA approx. 2.5 fold. This effect was driven by ERK1/2 acting upon PAC1/VPAC2 receptors. In turn, PACAP-treated 3T3-L1 adipocytes in co-cultures with DRG cells enhanced neurite ramification of neurofilament 200 (NF200)-positive neurons (measured using fluorescence microscopy) and neurofilament 68 protein levels (measured using Western blot analysis). This effect could be blocked using the PAC1/VPAC2 antagonist PACAP(6-38). Scanning cytometry revealed PACAP/ApoD induced low density lipoprotein receptors (LDLR) and ApoE receptor 2 (apoER2) in NF200-positive cells. Thus, a bidirectional loop seems to exist regulating the innervation of fatty tissues: PACAP released from sensory fibres might stimulate fat cells to synthesize neurotrophic adipokines, which, in turn, support peripheral innervation. PMID:20920539

Kosacka, Joanna; Schröder, Thomas; Bechmann, Ingo; Klöting, Nora; Nowicki, Marcin; Mittag, Anja; Gericke, Martin; Spanel-Borowski, Katharina; Blüher, Matthias

2011-01-01

110

Type III secretion needle proteins induce cell signaling and cytokine secretion via Toll-like receptors.  

PubMed

Pathogens are recognized by hosts by use of various receptors, including the Toll-like receptor (TLR) and Nod-like receptor (NLR) families. Ligands for these varied receptors, including bacterial products, are identified by the immune system, resulting in development of innate immune responses. Only a couple of components from type III secretion (T3S) systems are known to be recognized by TLR or NLR family members. Known T3S components that are detected by pattern recognition receptors (PRRs) are (i) flagellin, detected by TLR5 and NLRC4 (Ipaf); and (ii) T3S rod proteins (PrgJ and homologs) and needle proteins (PrgI and homologs), detected by NAIP and the NLRC4 inflammasome. In this report, we characterize the induction of proinflammatory responses through TLRs by the Yersinia pestis T3S needle protein, YscF, the Salmonella enterica needle proteins PrgI and SsaG, and the Shigella needle protein, MxiH. More specifically, we determine that the proinflammatory responses occur through TLR2 and -4. These data support the hypothesis that T3S needles have an unrecognized role in bacterial pathogenesis by modulating immune responses. PMID:24643544

Jessen, Danielle L; Osei-Owusu, Patrick; Toosky, Melody; Roughead, William; Bradley, David S; Nilles, Matthew L

2014-06-01

111

SirT3 Regulates the Mitochondrial Unfolded Protein Response  

PubMed Central

The mitochondria of cancer cells are characterized by elevated oxidative stress caused by reactive oxygen species (ROS). Such an elevation in ROS levels contributes to mitochondrial reprogramming and malignant transformation. However, high levels of ROS can cause irreversible damage to proteins, leading to their misfolding, mitochondrial stress, and ultimately cell death. Therefore, mechanisms to overcome mitochondrial stress are needed. The unfolded protein response (UPR) triggered by accumulation of misfolded proteins in the mitochondria (UPRmt) has been reported recently. So far, the UPRmt has been reported to involve the activation of CHOP and estrogen receptor alpha (ER?). The current study describes a novel role of the mitochondrial deacetylase SirT3 in the UPRmt. Our data reveal that SirT3 acts to orchestrate two pathways, the antioxidant machinery and mitophagy. Inhibition of SirT3 in cells undergoing proteotoxic stress severely impairs the mitochondrial network and results in cellular death. These observations suggest that SirT3 acts to sort moderately stressed from irreversibly damaged organelles. Since SirT3 is reported to act as a tumor suppressor during transformation, our findings reveal a dual role of SirT3. This novel role of SirT3 in established tumors represents an essential mechanism of adaptation of cancer cells to proteotoxic and mitochondrial stress. PMID:24324009

Papa, Luena

2014-01-01

112

Antiobesity Effects of an Edible Halophyte Nitraria retusa Forssk in 3T3-L1 Preadipocyte Differentiation and in C57B6J/L Mice Fed a High Fat Diet-Induced Obesity  

PubMed Central

Nitraria retusa is an edible halophyte, used in Tunisia for several traditional medicine purposes. The present study investigated the antiobesity effects of Nitraria retusa ethanol extract (NRE) in 3T3-L1 cells using different doses and in high-fat diet-induced obesity in mice. Male C57B6J/L mice were separately fed a normal diet (ND) or a high-fat diet (HFD) and daily administrated with NRE (50, 100?mg/kg) or one for 2 days with Naringenin (10?mg/kg). NRE administration significantly decreased body weight gain, fat pad weight, serum glucose, and lipid levels in HFD-induced obese mice. To elucidate the mechanism of action of NRE, the expression of genes involved in lipid and carbohydrate metabolism were measured in liver. Results showed that mice treated with NRE demonstrated a significant decrease in cumulative body weight and fat pad weight, a significant lowering in glucose and triglycerides serum levels, and an increase in the HDL-cholesterol serum level. Moreover mRNA expression results showed an enhancement of the expression of genes related to liver metabolism. Our findings suggest that NRE treatment had a protective or controlling effect against a high fat diet-induced obesity in C57B6J/L mice through the regulation of expression of genes involved in lipolysis and lipogenesis and thus the enhancement of the lipid metabolism in liver. PMID:24367387

Zar Kalai, Feten; Han, Junkyu; Ksouri, Riadh; El Omri, Abdelfatteh; Abdelly, Chedly; Isoda, Hiroko

2013-01-01

113

Lipolytic and antiadipogenic effects of (3,3-dimethylallyl) halfordinol on 3T3-L1 adipocytes and high fat and fructose diet induced obese C57/BL6J mice.  

PubMed

Aegle marmelos Correa., (Rutaceae) is a medium sized tree distributed in South East Asia and used traditionally for the management of obestiy and diabetes. In this study the lipolytic and antiadipogenic effects of (3,3-dimethylallyl) halfordinol (Hfn) isolated from leaves of A. marmelos have been investigated. Intracellular lipid accumulation was measured by oil red O staining and glycerol secretion. The expression of genes related to adipocyte differentiation was analyzed by reverse transcriptase-polymerase chain reaction (RT-PCR). Hfn decreased intracellular triglyceride accumulation and increased glycerol release in a dose dependent manner (5-20 ?g/ml) in differentiated 3T3-L1 adipocytes. In high fat diet fed C57/BL 6J mice, treatment with Hfn for four weeks reduced plasma glucose, insulin and triglyceride levels and showed a significant reduction in total adipose tissue mass by 37.85% and visceral adipose tissue mass by 62.99% at 50mg/kg b.w. concentration. RT-PCR analyses indicated that Hfn decreased the expression of peroxisome proliferator-activated receptor ? (PPAR?) and CCAAT enhancer binding protein ? (CEBP?) and increased the expression of sterol regulatory enzyme binding protein (SREBP-1c), peroxisome proliferator-activated receptor ? (PPAR?), Adiponectin and Glucose transporter protein 4 (GLUT4) compared to the high fat diet group. These results suggested that Hfn decreased adipocyte differentiation and stimulated lipolysis of adipocytes. This study justifies the folklore medicinal uses and claims about the therapeutic values of this plant for the management of insulin resistance and obesity. PMID:24952133

Saravanan, Munisankar; Pandikumar, Perumal; Saravanan, Subramaniam; Toppo, Erenius; Pazhanivel, Natesan; Ignacimuthu, Savarimuthu

2014-10-01

114

Suppression of cadmium-induced JNK/p38 activation and HSP70 family gene expression by LL-Z1640-2 in NIH3T3 cells.  

PubMed

When NIH3T3 cells were exposed to CdCl(2), the three major mitogen-activated protein kinases (MAPKs), extracellular signal-regulated protein kinase (ERK), c-Jun NH(2)-terminal kinase (JNK), and p38, were phosphorylated in a time (1-9 h)- and dose (1-20 microM)-dependent manner. Treatment with a macrocyclic nonaketide compound, LL-Z1640-2 (10-100 ng/ml), suppressed the phosphorylation of MAPKs without affecting the total protein level in cells exposed to 10 microM CdCl(2) for 6 h. CdCl(2)-induced phosphorylation of c-Jun on Ser63 and that on Ser73, and resultant accumulation of total c-Jun protein were also suppressed by LL-Z1640-2 treatment. The in vitro kinase assays also showed significant inhibitory effects of LL-Z1640-2 (at 10 or 25 ng/ml) on JNK and p38 but less markedly. In contrast to JNK and p38, ERK activity was inhibited moderately only at 50 or 100 ng/ml LL-Z1640-2. On the other hand, other JNK inhibitors, SP600125 and L-JNKI1, failed to suppress CdCl(2)-induced activation of the JNK pathway. Among the mouse stress response genes upregulated in response to CdCl(2) exposure, the expressions of hsp68 (encoding for heat shock 70 kDa protein 1; Hsp70-1) and grp78 (encoding for 78 kDa glucose-regulated protein; Grp78) genes were suppressed by treatment with 25 ng/ml LL-Z1640-2. Thus, LL-Z1640-2 could suppress CdCl(2)-induced activation of JNK/p38 pathways and expression of HSP70 family genes in NIH3T3 cells. LL-Z1640-2 seems to be useful to analyze functions of toxic metal-induced JNK/p38 activation. PMID:15081267

Sugisawa, Nobusuke; Matsuoka, Masato; Okuno, Takeo; Igisu, Hideki

2004-04-15

115

Subthalamotomy-induced changes in dopamine receptors in parkinsonian monkeys.  

PubMed

Subthalamotomy allows a reduction of doses of l-DOPA in dyskinetic patients while its antiparkinsonian benefits are preserved. However, the mechanisms of the potentiation of this response to medication remain to be elucidated. Hence, dopamine D1 and D2 receptors as well as the dopamine transporter were investigated using receptor binding autoradiography. D1 and D2 receptors as well as preproenkephalin and preprodynorphin mRNA levels were measured by in situ hybridization. Four dyskinetic 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) parkinsonian monkeys that underwent unilateral subthalamotomy were compared to four controls, four saline-treated and four l-DOPA-treated MPTP monkeys. Dopamine, its metabolites and its transporter were extensively and similarly decreased in all parkinsonian monkeys. D1 receptor specific binding was decreased in the striatum of all MPTP monkeys. The l-DOPA-induced decrease in D1 receptor specific binding was reversed in the striatum ipsilateral to subthalamotomy. D1 receptor mRNA levels followed a similar pattern. D2 receptor specific binding and mRNA levels remained unchanged in all groups. Striatal preproenkephalin mRNA levels were overall increased in MPTP monkeys; the STN-lesioned parkinsonian group had significantly lower values than the saline-treated and l-DOPA-treated parkinsonian monkeys in the dorsolateral putamen. Striatal preprodynorphin mRNA levels remained unchanged in MPTP monkeys compared to controls whereas it increased in all monkeys treated with l-DOPA compared to controls; subthalamotomy induced a decrease in the dorsolateral putamen ipsilateral to surgery. The improved motor response to l-DOPA after subthalamotomy in the parkinsonian monkeys investigated may be associated with an increased synthesis and expression of D1 receptors ipsilateral to STN lesion of the direct pathway. PMID:25172808

Jourdain, Vincent A; Morin, Nicolas; Morissette, Marc; Grégoire, Laurent; Di Paolo, Thérčse

2014-11-01

116

Ethanol-induced free radical injury to the hepatocyte glucagon receptor  

Microsoft Academic Search

Plasma membrane receptors are essential in cellular homeostasis. Free radical generation and catalytic iron have been implicated in alcohol-induced liver injury; damage to plasma membrane receptors may be one important mechanisms of injury. The effect of ethanol-induced free radicals on hepatocyte receptor dysfunction was investigated in rodent models of free radical injury due to chronic alcohol administration. Receptors for glucagon

Spencer Shaw; John Eng; Elizabeth Jayatilleke

1995-01-01

117

Prostaglandin E2-induced up-regulation of c-fos messenger ribonucleic acid is primarily mediated by 3',5'-cyclic adenosine monophosphate in MC3T3-E1 osteoblasts  

NASA Technical Reports Server (NTRS)

The mechanism by which the proto-oncogene, c-fos, is up-regulated in response to PGE2 in the mouse osteoblastic (MC3T3-E1) cell line was investigated using RT-PCR. c-fos messenger RNA up-regulation by dmPGE2 is rapid, starting 10 min post stimulation, and transient. The specific protein kinase A (PKA) inhibitor, H89, inhibited c-fos induction. Moreover, down-regulation of protein kinase C (PKC) activity by chronic TPA treatment had no effect on the induction of c-fos by dmPGE2. We conclude that up-regulation of c-fos by dmPGE2 is primarily dependent on PKA in MC3T3-E1 osteoblasts. In S49 lymphoma wild-type but not S49 cyc- cells, which are deficient in cAMP signaling, dmPGE2 up-regulates c-fos and increases cell growth compared with unstimulated cells. Thus in S49 lymphoma cells, c-fos induction by PGE2 is also dependent on cAMP signaling. The minimal c-fos promoter region required for dmPGE2-induced expression was identified by transfecting c-fos promoter deletion constructs coupled to the chloramphenicol acetyltransferase (CAT) reporter gene into Vero cells. Transfection of a plasmid containing 99 bp c-fos proximal promoter was sufficient to direct c-fos/CAT expression following stimulation with dmPGE2. Because induction of c-fos is mediated by cAMP, these data are consistent with activation of c-fos via the CRE/ATF cis element.

Fitzgerald, J.; Dietz, T. J.; Hughes-Fulford, M.

2000-01-01

118

Valsartan, independently of AT1 receptor or PPAR?, suppresses LPS-induced macrophage activation and improves insulin resistance in cocultured adipocytes.  

PubMed

Macrophages are integrated into adipose tissues and interact with adipocytes in obese subjects, thereby exacerbating adipose insulin resistance. This study aimed to elucidate the molecular mechanism underlying the insulin-sensitizing effect of the angiotensin II receptor blocker (ARB) valsartan, as demonstrated in clinical studies. Insulin signaling, i.e., insulin receptor substrate-1 and Akt phosphorylations, in 3T3-L1 adipocytes was impaired markedly by treatment with tumor necrosis factor-? (TNF?) or in the culture medium of lipopolysaccharide (LPS)-stimulated RAW 264.7 murine macrophages, and valsartan had no effects on these impairments. However, in contrast, when cocultured with RAW 264.7 cells using a transwell system, the LPS-induced insulin signaling impairment in 3T3-L1 adipocytes showed almost complete normalization with coaddition of valsartan. Furthermore, valsartan strongly suppressed LPS-induced productions of cytokines such as interleukin (IL)-1?, IL-6, and TNF? with nuclear factor-?B activation and c-Jun NH(2)-terminal kinase phosphorylation in RAW 264.7 and primary murine macrophages. Very interestingly, this effect of valsartan was also observed in THP-1 cells treated with angiotensin II type 1 (AT1) siRNA or a peroxisome proliferator-activated receptor-? (PPAR?) antagonist as well as macrophages from AT1a receptor-knockout mice. We conclude that valsartan suppresses the inflammatory response of macrophages, albeit not via PPAR? or the AT1a receptor. This suppression appears to secondarily improve adipose insulin resistance. PMID:22045314

Iwashita, Misaki; Sakoda, Hideyuki; Kushiyama, Akifumi; Fujishiro, Midori; Ohno, Haruya; Nakatsu, Yusuke; Fukushima, Toshiaki; Kumamoto, Sonoko; Tsuchiya, Yoshihiro; Kikuchi, Takako; Kurihara, Hiroki; Akazawa, Hiroshi; Komuro, Issei; Kamata, Hideaki; Nishimura, Fusanori; Asano, Tomoichiro

2012-02-01

119

Suppressive effects of chlorophyllin on mutagen-induced umu C gene expression in Salmonella typhimurium (TA 1535/pSK 1002) and tumor promoter-dependent ornithine decarboxylase induction in BALB/c 3T3 fibroblast cells.  

PubMed

The potentially protective role of chlorophyllin, the sodium and copper salt of chlorophyll a against the initiation and promotion stages in carcinogenesis was studied by in vitro short-term assays. Chlorophyllin showed a dose-dependent suppressive effect on 3-amino-1,4-dimethyl-5H-pyrido[4,3-b]indol (Trp-P-1)-induced umu C gene expression of Salmonella typhimurium (TA 1535/pSK 1002) in the presence of metabolizing enzyme mixture. The similar inhibitory effect of chlorophyllin was detected in mitomycin C (MMC)-dependent umu C gene expression in the absence of metabolizing enzyme mixture. Furthermore chlorophyllin also exhibited a dose-dependent inhibition on 12-O-tetradecanoyl-phorbol-13-acetate (TPA)-induced ornithine decarboxylase (ODC) activity of 3T3 fibroblast cells at the same concentrations. However, when chlorophyll a isolated from Japanese tea leaves was applied on the same assay systems as a comparative experiment, chlorophyll a showed much weaker activity compared with that of chlorophyllin. The significance of this finding is discussed from the viewpoint of the protective role of chlorophyllin against carcinogenesis. PMID:8830802

Okai, Y; Higashi-Okai, K; Yano, Y; Otani, S

1996-08-01

120

TRPA1 receptors mediate environmental irritant-induced meningeal vasodilatation.  

PubMed

The TRPA1 receptor is a member of the transient receptor potential (TRP) family of ion channels expressed in nociceptive neurons. TRPA1 receptors are targeted by pungent compounds from mustard and garlic and environmental irritants such as formaldehyde and acrolein. Ingestion or inhalation of these chemical agents causes irritation and burning in the nasal and oral mucosa and respiratory lining. Headaches have been widely reported to be induced by inhalation of environmental irritants, but it is unclear how these agents produce headache. Stimulation of trigeminal neurons releases CGRP and substance P and induces neurogenic inflammation associated with the pain of migraine. Here we test the hypothesis that activation of TRPA1 receptors is the mechanistic link between environmental irritants and peptide-mediated neurogenic inflammation. Known TRPA1 agonists and environmental irritants stimulate CGRP release from dissociated rat trigeminal ganglia neurons and this release is blocked by a selective TRPA1 antagonist, HC-030031. Further, TRPA1 agonists and environmental irritants increase meningeal blood flow following intranasal administration. Prior dural application of the CGRP antagonist, CGRP(8-37), or intranasal or dural administration of HC-030031, blocks the increases in blood flow elicited by environmental irritants. Together these results demonstrate that TRPA1 receptor activation by environmental irritants stimulates CGRP release and increases cerebral blood flow. We suggest that these events contribute to headache associated with environmental irritants. PMID:21075522

Kunkler, Phillip Edward; Ballard, Carrie Jo; Oxford, Gerry Stephen; Hurley, Joyce Harts

2011-01-01

121

Stress induces pain transition by potentiation of AMPA receptor phosphorylation.  

PubMed

Chronic postsurgical pain is a serious issue in clinical practice. After surgery, patients experience ongoing pain or become sensitive to incident, normally nonpainful stimulation. The intensity and duration of postsurgical pain vary. However, it is unclear how the transition from acute to chronic pain occurs. Here we showed that social defeat stress enhanced plantar incision-induced AMPA receptor GluA1 phosphorylation at the Ser831 site in the spinal cord and greatly prolonged plantar incision-induced pain. Interestingly, targeted mutation of the GluA1 phosphorylation site Ser831 significantly inhibited stress-induced prolongation of incisional pain. In addition, stress hormones enhanced GluA1 phosphorylation and AMPA receptor-mediated electrical activity in the spinal cord. Subthreshold stimulation induced spinal long-term potentiation in GluA1 phosphomimetic mutant mice, but not in wild-type mice. Therefore, spinal AMPA receptor phosphorylation contributes to the mechanisms underlying stress-induced pain transition. PMID:25297100

Li, Changsheng; Yang, Ya; Liu, Sufang; Fang, Huaqiang; Zhang, Yong; Furmanski, Orion; Skinner, John; Xing, Ying; Johns, Roger A; Huganir, Richard L; Tao, Feng

2014-10-01

122

Extract of Chaga mushroom (Inonotus obliquus) stimulates 3T3-L1 adipocyte differentiation.  

PubMed

Chaga mushroom (Inonotus obliquus) has long been used as a folk medicine due to its numerous biological functions such as antibacterial, antiallergic, antiinflammatory and antioxidative activities. In the present study, it was found that the I. obliquus hot water extract (IOWE) activated adipogenesis of 3T3-L1 preadipocytes. Even in the absence of adipogenic stimuli by insulin, the IOWE strongly induced adipogenesis of 3T3-L1 preadipocytes. The major constituent of IOWE was glucose-rich polysaccharides with a molecular mass of 149? kDa. IOWE enhanced the differentiation of 3T3-L1 preadipocytes, increasing TG (triacylglycerol) accumulation that is critical for acquisition of the adipocyte phenotype, in a dose-dependent manner. IOWE stimulated gene expression of C/EBP? (CCAAT/enhancer-binding protein ?) and PPAR? (peroxisome proliferator-activated receptors ?) during adipocyte differentiation, and induced the expression of PPAR? target genes such as aP2 (adipocyte protein 2), LPL (lipoprotein lipase) and CD36 (fatty acid translocase). Immunoblot analysis revealed that IOWE increased the expression of adipogenic makers such as PPAR? and GLUT4 (glucose transporter 4). The luciferase reporter assay demonstrated that IOWE did not exhibit PPAR? ligand activity. Although these results require further investigation, the ability of natural mushroom product to increase PPAR? transcriptional activities may be expected to be therapeutic targets for dyslipidemia and type 2 diabetes. PMID:21031614

Joo, Jeong In; Kim, Dong Hyun; Yun, Jong Won

2010-11-01

123

Deletion of the thyroid hormone receptor 1 prevents the structural alterations of the cerebellum induced by hypothyroidism  

Microsoft Academic Search

Thyroid hormone (T3) controls critical aspects of cerebellar development, such as migration of postmitotic granule cells and terminal differentiation of Purkinje cells. T3 acts through nuclear receptors (TR) of two types, TR1 and TR, that either repress or activate gene expression. We have analyzed the cerebellar structure of developing mice lacking the TR1 isoform, which normally accounts for about 80%

Beatriz Morte; Jimena Manzano; Thomas Scanlan; Björn Vennström; Juan Bernal

2002-01-01

124

Dark chocolate receptors: epicatechin-induced cardiac protection is dependent on ?-opioid receptor stimulation  

PubMed Central

Epicatechin, a flavonoid, is a well-known antioxidant linked to a variety of protective effects in both humans and animals. In particular, its role in protection against cardiovascular disease has been demonstrated by epidemiologic studies. Low-dose epicatechin, which does not have significant antioxidant activity, is also protective; however, the mechanism by which low-dose epicatechin induces this effect is unknown. Our laboratory tested the hypothesis that low-dose epicatechin mediates cardiac protection via opioid receptor activation. C57BL/6 mice were randomly assigned to 1 of 10 groups: control, epicatechin, naloxone (nonselective opioid receptor antagonist), epicatechin + naloxone, naltrindole (?-specific opioid receptor antagonist), epicatechin + naltrindole, norbinaltorphimine (nor-BNI, ?-specific opioid receptor antagonist), epicatechin + nor-BNI, 5-hydroxydecanoic acid [5-HD, ATP-sensitive potassium channel antagonist], and epicatechin + 5-HD. Epicatechin (1 mg/kg) or other inhibitors (5 mg/kg) were administered by oral gavage or intraperitoneal injection, respectively, daily for 10 days. Mice were subjected to 30 min coronary artery occlusion followed by 2 h of reperfusion, and infarct size was determined via planimetry. Whole heart homogenates were assayed for downstream opioid receptor signaling targets. Infarct size was significantly reduced in epicatechin- and epicatechin + nor-BNI-treated mice compared with control mice. This protection was blocked by naloxone, naltrindole, and 5-HD. Epicatechin and epicatechin + nor-BNI increased the phosphorylation of Src, Akt, and I?B?, while simultaneously decreasing the expression of c-Jun NH2-terminal kinase and caspase-activated DNase. All signaling effects are consistent with opioid receptor stimulation and subsequent cardiac protection. Naloxone, naltrindole, and 5-HD attenuated these effects. In conclusion, epicatechin acts via opioid receptors and more specifically through the ?-opioid receptor to produce cardiac protection from ischemia-reperfusion injury. PMID:20833967

Panneerselvam, Mathivadhani; Tsutsumi, Yasuo M.; Bonds, Jacqueline A.; Horikawa, Yousuke T.; Saldana, Michelle; Dalton, Nancy D.; Head, Brian P.; Patel, Piyush M.; Roth, David M.

2010-01-01

125

Different effects of NMDA\\/group I metabotropic glutamate receptor agents in ?- and ?-opioid receptor agonist-induced supraspinal antinociception  

Microsoft Academic Search

The N-methyl-d-aspartate (NMDA) and metabotropic glutamate (mGlu) receptors are involved in nociceptive transmission in the central nervous system. The present study was designed to study the effects of NMDA and group I mGlu receptor agents on ?- and ?-opioid receptor agonist-induced antinociception in the mouse brain. Intracerebroventricular (i.c.v.) treatment with the non-competitive NMDA receptor antagonist dizocilpine and the group I

Tsutomu Suzuki; Takeshi Aoki; Orie Ohnishi; Hiroshi Nagase; Minoru Narita

2000-01-01

126

Antigenic targeting of the human mannose receptor induces tumor immunity.  

PubMed

Pattern recognition receptors are preferentially expressed on APCs allowing selective uptake of pathogens for the initiation of antimicrobial immunity. In particular, C-type lectin receptors, including the mannose receptor (MR), facilitate APC-mediated adsorptive endocytosis of microbial glyconjugates. We have investigated the potential of antigenic targeting to the MR as a means to induce Ag-specific humoral and cellular immunity. hMR transgenic (hMR Tg) mice were generated to allow specific targeting with the anti-hMR Ab, B11. We show that hMR targeting induced both humoral and cellular antigenic specific immunity. Immunization of hMR Tg mice with B11 mAbs induced potent humoral responses independent of adjuvant. Injection of hMR Tg mice with mouse anti-hMR Ab clone 19.2 elicited anti-Id-specific humoral immunity while non-Tg mice were unresponsive. B11-OVA fusion proteins (B11-OVA) were efficiently presented to OVA-specific CD4 and CD8 T cells in MR Tg, but not in non-Tg, mice. Effector differentiation of responding T cells in MR Tg mice was significantly enhanced with concomitant immunization with the TLR agonist, CpG. Administration of both CpG and B11-OVA to hMR Tg mice induced OVA-specific tumor immunity while WT mice remained unprotected. These studies support the clinical development of immunotherapeutic approaches in cancer using pattern recognition receptor targeting systems for the selective delivery of tumor Ags to APCs. PMID:17475854

He, Li-Zhen; Crocker, Andrea; Lee, Janine; Mendoza-Ramirez, Jose; Wang, Xi-Tao; Vitale, Laura A; O'Neill, Thomas; Petromilli, Chris; Zhang, Hui-Fen; Lopez, Joe; Rohrer, Dan; Keler, Tibor; Clynes, Raphael

2007-05-15

127

Adenosine A3 receptor stimulation induces protection of skeletal muscle from eccentric exercise-mediated injury  

E-print Network

Adenosine A3 receptor stimulation induces protection of skeletal muscle from eccentric exercise, Zambraski EJ, Rader EP, Campbell KP, Liang BT. Adenosine A3 receptor stimulation induces protection of this study was to determine whether adenosine receptor stimulation can mediate protection from eccentric

Campbell, Kevin P.

128

FEBS J . Author manuscript Visfatin is induced by peroxisome proliferator-activated receptor gamma in  

E-print Network

FEBS J . Author manuscript Page /1 11 Visfatin is induced by peroxisome proliferator/PBEF/NAMPT. The nuclear receptor Peroxisome Proliferator-Activated Receptor (PPAR) exerts anti-inflammatory effects

Boyer, Edmond

129

2-Adrenergic receptor supports prolonged theta tetanus-induced LTP Lucas Matt,2  

E-print Network

2-Adrenergic receptor supports prolonged theta tetanus-induced LTP Hai Qian,1 Lucas Matt,2 Mingxu, Lee HK, Hell JW. 2-Adrenergic receptor supports prolonged theta tetanus-induced LTP. J Neurophysiol-term potentiation (LTP) induced by a train of 900 stimuli at 5 Hz (prolonged theta-tetanus-LTP, or PTT

Lee, Hey-Kyoung

130

Bone marrow-derived cultured mast cells and peritoneal mast cells as targets of a growth activity secreted by BALB/3T3 fibroblasts  

SciTech Connect

When fibroblast cell lines were cultured in contact with bone marrow-derived cultured mast cells (CMC), both NIH/3T3 and BALB/3T3 cell lines supported the proliferation of CMC. In contrast, when contact between fibroblasts and CMC was prohibited by Biopore membranes or soft agar, only BALB/3T3 fibroblasts supported CMC proliferation, suggesting that BALB/3T3 but not NIH/3T3 cells secreted a significant amount of a mast cell growth activity. Moreover, the BALB/3T3-derived growth activity induced the incorporation of (3H)thymidine by CMC and the clonal growth of peritoneal mast cells in methylcellulose. The mast cell growth activity appeared to be different from interleukin 3 (IL-3) and interleukin 4 (IL-4), because mRNAs for these interleukins were not detectable in BALB/3T3 fibroblasts. Although mast cells are genetically deficient in tissues of W/Wv mice, CMC did develop when bone marrow cells of W/Wv mice were cultured with pokeweed mitogen-stimulated spleen cell-conditioned medium. Because BALB/3T3 fibroblast-conditioned medium (BALB-FCM) did not induce the incorporation of (3H)thymidine by W/Wv CMC, the growth activity in BALB-FCM appeared to be a ligand for the receptor encoded by the W (c-kit) locus. Because CMC and peritoneal mast cells are obtained as homogeneous suspensions rather easily, these cells may be potentially useful as targets for the fibroblast-derived mast cell growth activity.

Jozaki, K.; Kuriu, A.; Hirota, S.; Onoue, H.; Ebi, Y.; Adachi, S.; Ma, J.Y.; Tarui, S.; Kitamura, Y. (Osaka Univ. Medical School (Japan))

1991-03-01

131

207 Gsa signalling suppresses PPARg2 generation and inhibits 3T3L1 adipogenesis  

E-print Network

Since TSH receptor (TSHR) expression increases during adipogenesis and signals via cAMP/phospho-cAMP-response element binding protein (CREB), reported to be necessary and sufficient for adipogenesis, we hypothesised that TSHR activation would induce preadipocyte differentiation. Retroviral vectors introduced constitutively active TSHR (TSHR*) into 3T3L1 preadipocytes; despite increased cAMP (RIA) and phospho-CREB (western blot) there was no spontaneous adipogenesis (assessed morphologically, using oil red O and QPCR measurement of adipogenesis markers). We speculated that Gbg signalling may be inhibitory but failed to induce adipogenesis using activated Gsa (gsp*). Inhibition of phosphodiesterases did not promote adipogenesis in TSHR * or gsp * populations. Furthermore, differentiation induced by adipogenic medium with pioglitazone was reduced in TSHR * and abolished in gsp * expressing 3T3L1 cells. TSHR * and gsp * did not inactivate PPARg (PPARG as listed in the HUGO database) by phosphorylation but expression of PPARg1 was reduced and PPARg2 undetectable in gsp*. FOXO1 phosphorylation (required to inactivate this repressor of adipogenesis) was lowest in gsp * despite the activation of AKT by phosphorylation. PROF is a mediator that facilitates FOXO1 phosphorylation by phospho-Akt. Its transcript levels remained constantly low in the gsp* population. In most measurements, the TSHR * cells were between the gsp * and control 3T3L1 preadipocytes. The enhanced down-regulation of PREF1 (adipogenesis inhibitor) permits retention of some adipogenic potential in the TSHR * population. We conclude that Gsa signalling impedes FOXO1 phosphorylation and thus inhibits PPARg transcription and the alternative promoter usage required to generate PPARg2, the fat-specific transcription factor necessary for adipogenesis.

Lei Zhang; Carol Paddon; Mark D Lewis; Fiona Grennan-jones; Marian Ludgate

132

Estradiol-induced estrogen receptor-alpha trafficking.  

PubMed

Estradiol has rapid actions in the CNS that are mediated by membrane estrogen receptors (ERs) and activate cell signaling pathways through interaction with metabotropic glutamate receptors (mGluRs). Membrane-initiated estradiol signaling increases the free cytoplasmic calcium concentration ([Ca(2+)](i)) that stimulates the synthesis of neuroprogesterone in astrocytes. We used surface biotinylation to demonstrate that ERalpha has an extracellular portion. In addition to the full-length ERalpha [apparent molecular weight (MW), 66 kDa], surface biotinylation labeled an ERalpha-immunoreactive protein (MW, approximately 52 kDa) identified by both COOH- and NH(2)-directed antibodies. Estradiol treatment regulated membrane levels of both proteins in parallel: within 5 min, estradiol significantly increased membrane levels of the 66 and 52 kDa ERalpha. Internalization, a measure of membrane receptor activation, was also increased by estradiol with a similar time course. Continuous treatment with estradiol for 24-48 h reduced ERalpha levels, suggesting receptor downregulation. Estradiol also increased mGluR1a trafficking and internalization, consistent with the proposed ERalpha-mGluR1a interaction. Blocking ER with ICI 182,780 or mGluR1a with LY 367385 prevented ERalpha trafficking to and from the membrane. Estradiol-induced [Ca(2+)](i) flux was also significantly increased at the time of peak ERalpha activation/internalization. These results demonstrate that ERalpha is present in the membrane and has an extracellular portion. Furthermore, membrane levels and internalization of ERalpha are regulated by estradiol and mGluR1a ligands. The pattern of trafficking into and out of the membrane suggests that the changing concentration of estradiol during the estrous cycle regulates ERalpha to augment and then terminate membrane-initiated signaling. PMID:19955385

Bondar, Galyna; Kuo, John; Hamid, Naheed; Micevych, Paul

2009-12-01

133

Carnosic acid inhibits TLR4-MyD88 signaling pathway in LPS-stimulated 3T3-L1 adipocytes  

PubMed Central

BACKGROUND/OBJECTIVES Carnosic acid (CA), found in rosemary (Rosemarinus officinalis) leaves, is known to exhibit anti-obesity and anti-inflammatory activities. However, whether its anti-inflammatory potency can contribute to the amelioration of obesity has not been elucidated. The aim of the current study was to investigate the effect of CA on Toll-like receptor 4 (TLR4) pathways in the presence of lipopolysaccharide (LPS) in 3T3-L1 adipocytes. MATERIALS/METHODS 3T3-L1 adipocytes were treated with CA (0-20 µM) for 1 h, followed by treatment with LPS for 30 min; mRNA expression of adipokines and protein expression of TLR4-related molecules were then measured. RESULTS LPS-stimulated 3T3-L1 adipocytes showed elevated mRNA expression of tumor necrosis factor (TNF)-?, interleukin-6, and monocyte chemoattractant protein-1, and CA significantly inhibited the expression of these adipokine genes. LPS-induced up regulation of TLR4, myeloid differentiation factor 88, TNF receptor-associated factor 6, and nuclear factor-?B, as well as phosphorylated extracellular receptor-activated kinase were also suppressed by pre-treatment of 3T3-L1 adipocytes with CA. CONCLUSIONS Results of this study suggest that CA directly inhibits TLR4-MyD88-dependent signaling pathways and decreases the inflammatory response in adipocytes.

Park, Mi-Young

2014-01-01

134

GABAA receptors modulate ethanol-induced conditioned place preference and taste aversion in mice  

Microsoft Academic Search

Rationale: GABAA receptor antagonists have been shown to reduce ethanol self-administration and ethanol-induced conditioned taste aversion\\u000a (CTA) in rats, suggesting a role for the GABAA receptor in modulating ethanol’s motivational effects. Objectives: The present experiments examined the effects of the GABAA receptor antagonists, bicuculline and picrotoxin, on the acquisition of ethanol-induced conditioned place preference (CPP)\\u000a and CTA in male DBA\\/2J

Julia A. Chester; Christopher L. Cunningham

1999-01-01

135

Proteinase-activated receptor 2 sensitizes transient receptor potential vanilloid 1, transient receptor potential vanilloid 4, and transient receptor potential ankyrin 1 in paclitaxel-induced neuropathic pain.  

PubMed

Paclitaxel chemotherapy is limited by a long-lasting painful neuropathy that lacks an effective therapy. In this study, we tested the hypothesis that paclitaxel may release mast cell tryptase, which activates protease-activated receptor 2 (PAR2) and, subsequently, protein kinases A and C, resulting in mechanical and thermal (both heat and cold) hypersensitivity. Correlating with the development of neuropathy after repeated administration of paclitaxel, mast cell tryptase activity was found to be increased in the spinal cord, dorsal root ganglia, and peripheral tissues in mice. FSLLRY-amide, a selective PAR2 antagonist, blocked paclitaxel-induced neuropathic pain behaviors in a dose- and time-dependent manner. In addition, blocking downstream signaling pathways of PAR2, including phospholipase C (PLC), protein kinase A (PKA), and protein kinase C? (PKC), effectively attenuated paclitaxel-induced mechanical, heat, or cold hypersensitivity. Furthermore, sensitized pain response was selectively inhibited by antagonists of transient receptor potential (TRP) V1, TRPV4, or TRPA1. These results revealed specific cellular signaling pathways leading to paclitaxel-induced neuropathy, including the activation of PAR2 and downstream enzymes PLC, PKC?, and PKA and resultant sensitization of TRPV1, TRPV4, and TRPA1. Targeting one or more of these signaling molecules may present new opportunities for the treatment of paclitaxel-induced neuropathy. PMID:21763756

Chen, Y; Yang, C; Wang, Z J

2011-10-13

136

Altered GABAB receptor immunoreactivity in the gerbil hippocampus induced by baclofen and phaclofen, not seizure activity.  

PubMed

The present study was performed to determine whether the effects induced by GABA(B) receptor-acting drugs would be related with the alteration in GABA(B) receptor expression in the hippocampus using Mongolian gerbil, a genetic epilepsy model. The distribution patterns of both GABA(B) receptor 1A/B and GABA(B)receptor 2 immunoreactivities were similarly detected in the hippocampi of normal and seizure-prone gerbils. Following baclofen (GABA(B) receptor agonist) or phaclofen (GABA(B) receptor antagonist) treatment, GABA(B) receptor immunoreactivities were decreased or increased by dose-dependent manners, respectively. Vigabatrin (GABA transaminase inhibitor) or 3-mercaptopropionic acid (GAD inhibitor) treatment did not affect GABA(B) receptor expressions. These findings suggest that GABA(B) receptor expression in the gerbil hippocampus may be altered by baclofen or phaclofen treatment. PMID:15236866

Park, Seung-Kook; An, Sung-Jin; Hwang, In Koo; Kim, Dae Won; Jung, Ju-Young; Won, Moo Ho; Choi, Soo-Young; Kwon, Oh-Shin; Jeong, Young-Gil; Kang, Tae-Cheon

2004-08-01

137

Kainate receptor activation induces glycine receptor endocytosis through PKC deSUMOylation.  

PubMed

Surface expression and regulated endocytosis of glycine receptors (GlyRs) play a critical function in balancing neuronal excitability. SUMOylation (SUMO modification) is of critical importance for maintaining neuronal function in the central nervous system. Here we show that activation of kainate receptors (KARs) causes GlyR endocytosis in a calcium- and protein kinase C (PKC)-dependent manner, leading to reduced GlyR-mediated synaptic activity in cultured spinal cord neurons and the superficial dorsal horn of rat spinal cord slices. This effect requires SUMO1/sentrin-specific peptidase 1 (SENP1)-mediated deSUMOylation of PKC, indicating that the crosstalk between KARs and GlyRs relies on the SUMOylation status of PKC. SENP1-mediated deSUMOylation of PKC is involved in the kainate-induced GlyR endocytosis and thus plays an important role in the anti-homeostatic regulation between excitatory and inhibitory ligand-gated ion channels. Altogether, we have identified a SUMOylation-dependent regulatory pathway for GlyR endocytosis, which may have important physiological implications for proper neuronal excitability. PMID:25236484

Sun, Hao; Lu, Li; Zuo, Yong; Wang, Yan; Jiao, Yingfu; Zeng, Wei-Zheng; Huang, Chao; Zhu, Michael X; Zamponi, Gerald W; Zhou, Tong; Xu, Tian-Le; Cheng, Jinke; Li, Yong

2014-01-01

138

Kainate receptor activation induces glycine receptor endocytosis through PKC deSUMOylation  

PubMed Central

Surface expression and regulated endocytosis of glycine receptors (GlyRs) play a critical function in balancing neuronal excitability. SUMOylation (SUMO modification) is of critical importance for maintaining neuronal function in the central nervous system. Here we show that activation of kainate receptors (KARs) causes GlyR endocytosis in a calcium- and protein kinase C (PKC)-dependent manner, leading to reduced GlyR-mediated synaptic activity in cultured spinal cord neurons and the superficial dorsal horn of rat spinal cord slices. This effect requires SUMO1/sentrin-specific peptidase 1 (SENP1)-mediated deSUMOylation of PKC, indicating that the crosstalk between KARs and GlyRs relies on the SUMOylation status of PKC. SENP1-mediated deSUMOylation of PKC is involved in the kainate-induced GlyR endocytosis and thus plays an important role in the anti-homeostatic regulation between excitatory and inhibitory ligand-gated ion channels. Altogether, we have identified a SUMOylation-dependent regulatory pathway for GlyR endocytosis, which may have important physiological implications for proper neuronal excitability. PMID:25236484

Sun, Hao; Lu, Li; Zuo, Yong; Wang, Yan; Jiao, Yingfu; Zeng, Wei-Zheng; Huang, Chao; Zhu, Michael X.; Zamponi, Gerald W.; Zhou, Tong; Xu, Tian-Le; Cheng, Jinke; Li, Yong

2014-01-01

139

Central antinociception induced by ketamine is mediated by endogenous opioids and ?- and ?-opioid receptors.  

PubMed

It is generally believed that NMDA receptor antagonism accounts for most of the anesthetic and analgesic effects of ketamine, however, it interacts at multiple sites in the central nervous system, including NMDA and non-NMDA glutamate receptors, nicotinic and muscarinic cholinergic receptors, and adrenergic and opioid receptors. Interestingly, it was shown that at supraspinal sites, ketamine interacts with the ?-opioid system and causes supraspinal antinociception. In this study, we investigated the involvement of endogenous opioids in ketamine-induced central antinociception. The nociceptive threshold for thermal stimulation was measured in Swiss mice using the tail-flick test. The drugs were administered via the intracerebroventricular route. Our results demonstrated that the opioid receptor antagonist naloxone, the ?-opioid receptor antagonist clocinnamox and the ?-opioid receptor antagonist naltrindole, but not the ?-opioid receptor antagonist nor-binaltorphimine, antagonized ketamine-induced central antinociception in a dose-dependent manner. Additionally, the administration of the aminopeptidase inhibitor bestatin significantly enhanced low-dose ketamine-induced central antinociception. These data provide evidence for the involvement of endogenous opioids and ?- and ?-opioid receptors in ketamine-induced central antinociception. In contrast, ?-opioid receptors not appear to be involved in this effect. PMID:24675031

Pacheco, Daniela da Fonseca; Romero, Thiago Roberto Lima; Duarte, Igor Dimitri Gama

2014-05-01

140

Tannic acid stimulates glucose transport and inhibits adipocyte differentiation in 3T3-L1 cells.  

PubMed

Obesity is a major risk factor for Syndrome X and type II diabetes (T2D). However, most antidiabetic drugs that are hypoglycemic also promote weight gain, thus alleviating one symptom of T2D while aggravating a major risk factor that leads to T2D. Adipogenesis, the differentiation and proliferation of adipocytes, is a major mechanism leading to weight gain and obesity. It is highly desirable to develop pharmaceuticals and treatments for T2D that reduce blood glucose levels without inducing adipogenesis in patients. Previously, we reported that an extract from Lagerstroemia speciosa L. (banaba) possessed activities that both stimulated glucose transport and inhibited adipocyte differentiation in 3T3-L1 cells. Using glucose uptake assays and Western/Northern blot analyses as major tools and 3T3-L1 cells as a model, we showed that the banaba extract (BE) with tannin removed was devoid of the 2 activities, and tannic acid (TA), a major component of tannins, had the same 2 activities as BE. Inhibitors known to abolish insulin-induced glucose transport also blocked TA-induced glucose transport. We further detected that TA induced phosphorylation of the insulin receptor (IR) and Akt, as well as translocation of glucose transporter 4 (GLUT 4), the protein factors involved in the signaling pathway of insulin-mediated glucose transport. We also demonstrated that TA inhibited the expression of key genes for adipogenesis. Differences between samples with or without TA in all of the quantitative assays were significant (P < 0.05). These results suggest that TA may be useful for the prevention and treatment of T2D and its associated obesity. TA may have the potential to become the lead compound in the development of new types of antidiabetic pharmaceuticals that are able to reduce blood glucose levels without increasing adiposity. PMID:15671208

Liu, Xueqing; Kim, Jae-kyung; Li, Yunsheng; Li, Jing; Liu, Fang; Chen, Xiaozhuo

2005-02-01

141

Effect of Ganoderma applanatum Mycelium Extract on the Inhibition of Adipogenesis in 3T3-L1 Adipocytes.  

PubMed

Abstract Ganoderma applanatum (GA) and related fungal species have been used for over 2000 years in China to prevent and treat various human diseases. However, there is no critical research evaluating the functionality of GA grown using submerged culture technology. This study aimed to evaluate the effects of submerged culture GA mycelium (GAM) and its active components (protocatechualdehyde [PCA]) on preadipocyte differentiation of 3T3-L1 cells. Mouse-derived preadipocyte 3T3-L1 cells were treated with differentiation inducers in the presence or absence of GAM extracts. We determined triglyceride accumulations, glycerol-3-phosphate dehydrogenase (GPDH) activities, and differentiation makers. PCA, the active component of GAM extract, was also used to treat 3T3-L1 cells. The MTT assay showed that the GAM extract (0.01-1?mg/mL) was not toxic to 3T3-L1 preadipocyte. Treatment of cells with GAM extracts and its active components significantly decreased the GPDH activity and lipid accumulation, a marker of adipogenesis, in a dose-dependent manner. Western blot analysis results showed that the protein expression levels of peroxisome proliferator-activated receptor ? (PPAR?), CCAAT/enhancer-binding protein ? (C/EBP?), and sterol regulatory element-binding protein 1 (SREBP1) were inhibited by the GAM extract. In addition, adipogenic-specific genes such as perilipin, fatty acid synthase (FAS), fatty acid transport protein 1 (FATP1), and fatty acid-binding protein 4 (FABP4) decreased in a dose-dependent manner. Quantitative high-performance liquid chromatography analysis showed that the GAM extract contained 1.14?mg/g PCA. GAM extracts suppressed differentiation of 3T3-L1 preadipocytes, in part, through altered regulation of PPAR?, C/EBP?, and SREBP1. These results suggest that GAM extracts and PCA may suppress adipogenesis by inhibiting differentiation of preadipocytes. PMID:25140758

Kim, Ji-Eun; Park, Sung-Jin; Yu, Mi-Hee; Lee, Sam-Pin

2014-10-01

142

Umbelliferone increases the expression of adipocyte-specific genes in 3?t3-l1 adipocyte.  

PubMed

Umbelliferone (UMB), a natural product of coumarin family, has been shown to reduce blood glucose and to improve lipid profiles in streptozotocin (STZ)-induced diabetic rats. Our objective was to examine the effect of UMB on adipogenesis by investigating its stimulatory effect on lipid accumulation and mRNA expression of adipogenic transcription factors and adipocyte-specific genes in 3?T3-L1 preadipocyte culture. An Oil Red O staining was used to monitor lipid accumulation, and we found that UMB treatment at concentration range of 10-100??M significantly increased lipid accumulation of differentiating 3?T3-L1 cells. At the molecular level of adipogenesis, we examined the mRNA expression of adipogenic transcription factors, peroxisome proliferator-activated receptor ?, CCAAT/enhancer-binding protein ?, and sterol regulatory element-binding protein 1c. Those transcription factors were increased by UMB at 10-100??M. Interestingly, UMB also stimulated the mRNA expression of adipocyte-specific genes, adipocyte fatty acid-binding protein, lipoprotein lipase, fatty acid synthase, fatty acid translocase, and adiponectin. Our findings indicate that the stimulatory effect of UMB on adipocyte differentiation likely occurs through up-regulation of adipogenic transcription factors and downstream adipocyte-specific gene expression. Copyright © 2014 John Wiley & Sons, Ltd. PMID:24853372

Naowaboot, Jarinyaporn; Chung, Choon Hee; Choi, Ran; Pannangpetch, Patchareewan

2014-11-01

143

?2-Adrenergic receptor supports prolonged theta tetanus-induced LTP  

PubMed Central

The widespread noradrenergic innervation in the brain promotes arousal and learning by molecular mechanisms that remain largely undefined. Recent work shows that the ?2-adrenergic receptor (?2AR) is linked to the AMPA-type glutamate receptor subunit GluA1 via stargazin and PSD-95 (Joiner ML, Lise MF, Yuen EY, Kam AY, Zhang M, Hall DD, Malik ZA, Qian H, Chen Y, Ulrich JD, Burette AC, Weinberg RJ, Law PY, El-Husseini A, Yan Z, Hell JW. EMBO J 29: 482–495, 2010). We now demonstrate that the ?2AR plays a prominent role in long-term potentiation (LTP) induced by a train of 900 stimuli at 5 Hz (prolonged theta-tetanus-LTP, or PTT-LTP) in the hippocampal CA1 region in mice, which requires simultaneous ?-adrenergic stimulation. Although PTT-LTP was impaired in hippocampal slices from ?1AR and ?2AR knockout (KO) mice, only ?2AR-selective stimulation with salbutamol supported this PTT-LTP in wild-type (WT) slices, whereas ?1AR-selective stimulation with dobutamine (+ prazosin) did not. Furthermore, only the ?2AR-selective antagonist ICI-118551 and not the ?1AR-selective antagonist CGP-20712 inhibited PTT-LTP and phosphorylation of GluA1 on its PKA site S845 in WT slices. Our analysis of S845A knockin (KI) mice indicates that this phosphorylation is relevant for PTT-LTP. These results identify the ?2AR-S845 signaling pathway as a prominent regulator of synaptic plasticity. PMID:22338020

Qian, Hai; Matt, Lucas; Zhang, Mingxu; Nguyen, Minh; Patriarchi, Tommaso; Koval, Olha M.; Anderson, Mark E.; He, Kaiwen; Lee, Hey-Kyoung

2012-01-01

144

?2-Adrenergic receptor supports prolonged theta tetanus-induced LTP.  

PubMed

The widespread noradrenergic innervation in the brain promotes arousal and learning by molecular mechanisms that remain largely undefined. Recent work shows that the ?(2)-adrenergic receptor (?(2)AR) is linked to the AMPA-type glutamate receptor subunit GluA1 via stargazin and PSD-95 (Joiner ML, Lise MF, Yuen EY, Kam AY, Zhang M, Hall DD, Malik ZA, Qian H, Chen Y, Ulrich JD, Burette AC, Weinberg RJ, Law PY, El-Husseini A, Yan Z, Hell JW. EMBO J 29: 482-495, 2010). We now demonstrate that the ?(2)AR plays a prominent role in long-term potentiation (LTP) induced by a train of 900 stimuli at 5 Hz (prolonged theta-tetanus-LTP, or PTT-LTP) in the hippocampal CA1 region in mice, which requires simultaneous ?-adrenergic stimulation. Although PTT-LTP was impaired in hippocampal slices from ?(1)AR and ?(2)AR knockout (KO) mice, only ?(2)AR-selective stimulation with salbutamol supported this PTT-LTP in wild-type (WT) slices, whereas ?(1)AR-selective stimulation with dobutamine (+ prazosin) did not. Furthermore, only the ?(2)AR-selective antagonist ICI-118551 and not the ?(1)AR-selective antagonist CGP-20712 inhibited PTT-LTP and phosphorylation of GluA1 on its PKA site S845 in WT slices. Our analysis of S845A knockin (KI) mice indicates that this phosphorylation is relevant for PTT-LTP. These results identify the ?(2)AR-S845 signaling pathway as a prominent regulator of synaptic plasticity. PMID:22338020

Qian, Hai; Matt, Lucas; Zhang, Mingxu; Nguyen, Minh; Patriarchi, Tommaso; Koval, Olha M; Anderson, Mark E; He, Kaiwen; Lee, Hey-Kyoung; Hell, Johannes W

2012-05-01

145

Variation in EGF-induced EGF receptor downregulation in human hepatoma-derived cell lines expressing different amounts of EGF receptor.  

PubMed

The effect of epidermal growth factor (EGF) receptor overexpression on ligand-induced EGF receptor downregulation was examined using a hepatoma-derived cell line, PLC/PRF/5, which expresses normal amounts of the EGF receptor, and a subline, NPLC/PRF/5, which expresses 10-fold more receptors at its cell surface. PLC/PRF/5 cells efficiently downregulated surface receptor levels upon exposure to saturating and subsaturating concentrations of EGF; the rate of receptor downregulation corresponded to that of ligand-receptor internalization. Upon internalization, EGF receptors were degraded and receptor biosynthesis remained at basal levels. EGF surface receptor remained downregulated for as long as cells were exposed to EGF. By contrast, surface EGF receptor abundance in NPLC/PRF/5 cells decreased by only 5-15% after 1-4 h incubation with subsaturating doses of EGF and actually increased by 67% within 20 h. Exposure of these cells to saturating concentrations of EGF induced modest decreases in surface receptor abundance during the initial 12 h incubation, followed by a progressive decline to 30% of initial values by 24 h. Relative ligand-receptor internalization rates in NPLC/PRF/5 cells were lower than those in PLC/PRF/5, although their surface receptor population was even higher than that predicted by the decreased internalization rates. EGF receptor degradation in NPLC/PRF/5 cells was also inhibited; exposure to saturating levels of EGF for more than 16 h was necessary before significant degradation occurred. Receptor protein and mRNA biosynthesis in NPLC/PRF/5 were stimulated by 8 h exposure to EGF but when saturating concentrations of EGF were present for 16 h, receptor biosynthesis was inhibited. EGF receptor overexpression circumvents the downregulatory effect of EGF by decreasing the rate of receptor internalization, inhibiting degradation of the internalized receptor pool, and stimulating EGF receptor biosynthesis. Conversely, receptor downregulation becomes pronounced at late times when receptor degradation is high and biosynthesis is inhibited. PMID:1315281

Gilligan, A; Bushmeyer, S; Knowles, B B

1992-06-01

146

Dexamethasone counteracts the immunostimulatory effects of triiodothyronine (T3) on dendritic cells  

Microsoft Academic Search

Glucocorticoids (GCs) are widely used as anti-inflammatory and immunosuppressive agents. Several studies have indicated the important role of dendritic cells (DCs), highly specialized antigen-presenting and immunomodulatory cells, in GC-mediated suppression of adaptive immune responses. Recently, we demonstrated that triiodothyronine (T3) has potent immunostimulatory effects on bone marrow-derived mouse DCs through a mechanism involving T3 binding to cytosolic thyroid hormone receptor

María M. Montesinos; Vanina A. Alamino; Iván D. Mascanfroni; Sebastián Susperreguy; Nicolás Gigena; Ana M. Masini-Repiso; Gabriel A. Rabinovich; Claudia G. Pellizas

147

Influence of nicotinic receptor modulators on CB2 cannabinoid receptor agonist (JWH133)-induced antinociception in mice.  

PubMed

Delta9-tetrahydrocannabinol is the active component in cannabis and has long been associated with pain relief. This effect is believed to be mediated through central and peripheral CB1 and peripheral CB2 receptors. We have explored the possible antinociceptive effect of a CB2 receptor agonist, JWH133, using the formalin test in mice. The drug was administered by the intracerebroventricular and intraperitoneal routes. Although no antinociceptive effect was observed after intracerebroventricular administration of JWH133, when the drug was administered by the intraperitoneal route, it produced an analgesic effect. The influence of nicotinic cholinergic receptor modulators, nicotine and mecamylamine, on antinociceptive effect of JWH133 was also studied. Nicotine increased and mecamylamine decreased the antinociceptive effect of JWH133. It is concluded that JWH133-induced analgesia is influenced by nicotinic cholinergic receptor activity. PMID:17912054

Jafari, Mohammad R; Golmohammadi, Somaye; Ghiasvand, Fereshteh; Zarrindast, Mohammad R; Djahanguiri, Bijan

2007-11-01

148

AMPA receptors mediate passive avoidance deficits induced by sleep deprivation.  

PubMed

The present study addressed the effects of sleep deprivation (SD) on AMPA receptor (AMPAR) binding in brain regions associated with learning and memory, and investigated whether treatment with drugs acting on AMPAR could prevent passive avoidance deficits in sleep deprived animals. [(3)H]AMPA binding and GluR1 in situ hybridization signals were quantified in different brain regions of male Wistar rats either immediately after 96 h of sleep deprivation or after 24h of sleep recovery following 96 h of sleep deprivation. Another group of animals were sleep deprived and then treated with either the AMPAR potentiator, aniracetam (25, 50 and 100mg/kg, acute administration) or the AMPAR antagonist GYKI-52466 (5 and 10mg/kg, acute and chronic administration) before passive avoidance training. Task performance was evaluated 2h and 24h after training. A significant reduction in [(3)H]AMPA binding was found in the hippocampal formation of SD animals, while no alterations were observed in GluR1 mRNA levels. The highest dose of aniracetam (100mg/kg) reverted SD-induced impairment of passive avoidance performance in both retention tests, whereas GYKI-52466 treatment had no effect. Pharmacological enhancement of AMPAR function may revert hippocampal-dependent learning impairments produced after SD. We argue that such effects might be associated with reduced AMPAR binding in the hippocampus of sleep deprived animals. PMID:24079994

Dubiela, Francisco Paulino; Queiroz, Claudio Marcos; Moreira, Karin Di Monteiro; Nobrega, Jose N; Sita, Luciane Valéria; Tufik, Sergio; Hipolide, Debora Cristina

2013-11-15

149

? 1Adrenergic receptor up-regulation induced by nadolol is mediated via signal transduction pathway coupled to ? 1-adrenergic receptors  

Microsoft Academic Search

Although up-regulation of ?-adrenergic receptors (?-ARs) occurs after long-term use of their antagonists in various tissues, the available data are little on mechanisms of ?-AR up-regulation induced by their continuous blockade. The present study attempted to clarify mechanisms of ?-AR up-regulation using mouse cerebral cortical neurons continuously exposed to nadolol (10nM), a non-selective ?-AR antagonist, for 24h. Nadolol dose-dependently induced

Koji Mizuno; Kazuhiro Kurokawa; Masahiro Shibasaki; Seitaro Ohkuma

2011-01-01

150

Effect of GR32191, a potent thromboxane receptor antagonist, on exercise induced bronchoconstriction in asthma  

Microsoft Academic Search

Previous work suggests a role for mast cell derived mediators in exercise induced asthma. The contribution of newly generated contractile prostaglandins to exercise induced asthma was assessed by using a potent and orally active thromboxane (TP1) receptor antagonist, GR32191. The effect of 120 mg GR32191 on exercise induced asthma was observed in 12 asthmatic subjects. For the exercise challenge the

J P Finnerty; O P Twentyman; A Harris; J B Palmer; S T Holgate

1991-01-01

151

Vasopressin rapidly stimulates protein kinase C in digitonin-permeabilized Swiss 3T3 cells: involvement of a pertussis toxin-insensitive guanine nucleotide binding protein.  

PubMed

Guanine nucleotides and pertussis toxin were used to test for the involvement of a guanine nucleotide binding protein in the vasopressin V1 receptor-mediated stimulation of protein kinase C activity in Swiss 3T3 cells. Addition of vasopressin in the presence of [gamma-32P]ATP and digitonin caused a marked and rapid increase (8 +/- 1-fold after 1 min) in the phosphorylation of an Mr = 80,000 cellular protein (80K), a specific marker for protein kinase C activation. This phosphorylation was selectively blocked by the V1 receptor antagonist Pmp1-0-Me-Tyr2 [Arg8] vasopressin, indicating that the effect was mediated through the vasopressin V1 receptor. Down regulation of protein kinase C by prior prolonged pretreatment of intact cells with phorbol 12,13-dibutyrate (PBt2) blocked the ability of vasopressin to stimulate the phosphorylation of 80K in digitonin-permeabilized cells. Addition of a submaximal concentration of vasopressin together with the GTP analogue GTP-gamma-S caused a synergistic stimulation of 80K phosphorylation. The GDP analogue GDP-beta-S caused a 50% inhibition of the phosphorylation of 80K induced by a saturating concentration of vasopressin and shifted the vasopressin dose-response curve to the right. GDP-beta-S had no effect on the dose-response for the stimulation of 80K phosphorylation induced by PBt2. Prior incubation of intact quiescent cultures of Swiss 3T3 cells with pertussis toxin did not impair either vasopressin-induced increase in cytosolic [Ca2+] or activation of protein kinase C. These findings provide functional evidence for the involvement of a pertussis toxin-insesitive G protein in the vasopressin V1 receptor-mediated stimulation of protein kinase C in Swiss 3T3 cells. PMID:2530240

Erusalimsky, J D; Rozengurt, E

1989-11-01

152

Local Anesthetics Affect Transmembrane Cytoskeletal Control of Mobility and Distribution of Cell Surface Receptors  

Microsoft Academic Search

Tertiary amine local anesthetics facilitated concanavalin A-induced redistribution of lectin receptors on murine BALB\\/3T3 cells and enhanced the susceptibility of these cells to agglutination by concanavalin A. In contrast, these drugs at similar concentrations inhibited ligand-induced capping of immunoglobulin receptors on mouse lymphocytes. We propose that these differing effects of local anesthetics on membrane receptor mobility in fibroblasts and lymphocytes

George Poste; Dimitri Papahadjopoulos; Garth L. Nicolson

1975-01-01

153

Thyroid Hormone Is an Inhibitor of Estrogen-Induced Degradation of Estrogen Receptor-Protein: Estrogen-  

E-print Network

Thyroid Hormone Is an Inhibitor of Estrogen-Induced Degradation of Estrogen Receptor- Protein in the control of receptor transcriptional activation function. Herein, we report that thyroid hormone can of the pituitary. The stabilization of ER pro- tein by thyroid hormone represents a selective blockade against

Alarid, Elaine T.

154

Activity-induced and developmental downregulation of the Nogo receptor  

Microsoft Academic Search

The three axon growth inhibitory proteins, myelin associated glycoprotein, oligodendrocyte-myelin glycoprotein and Nogo-A, can all bind to the Nogo-66 receptor (NgR). This receptor is expressed by neurons with high amounts in regions of high plasticity where Nogo expression is also high. We hypothesized that simultaneous presence of high levels of Nogo and its receptor in neurons confers a locked state

Anna Josephson; Alexandra Trifunovski; Camilla Schéele; Johan Widenfalk; Claes Wahlestedt; Stefan Brené; Lars Olson; Christian Spenger

2003-01-01

155

Rosiglitazone-Induced Mitochondrial Biogenesis in White Adipose Tissue Is Independent of Peroxisome Proliferator-Activated Receptor ? Coactivator-1?  

PubMed Central

Background Thiazolidinediones, a family of insulin-sensitizing drugs commonly used to treat type 2 diabetes, are thought to exert their effects in part by promoting mitochondrial biogenesis in white adipose tissue through the transcriptional coactivator PGC-1? (Peroxisome Proliferator-Activated Receptor ? Coactivator-1?). Methodology/Principal Findings To assess the role of PGC-1? in the control of rosiglitazone-induced mitochondrial biogenesis, we have generated a mouse model that lacks expression of PGC-1? specifically in adipose tissues (PGC-1?-FAT-KO mice). We found that expression of genes encoding for mitochondrial proteins involved in oxidative phosphorylation, tricarboxylic acid cycle or fatty acid oxidation, was similar in white adipose tissue of wild type and PGC-1?-FAT-KO mice. Furthermore, the absence of PGC-1? did not prevent the positive effect of rosiglitazone on mitochondrial gene expression or biogenesis, but it precluded the induction by rosiglitazone of UCP1 and other brown fat-specific genes in white adipose tissue. Consistent with the in vivo findings, basal and rosiglitazone-induced mitochondrial gene expression in 3T3-L1 adipocytes was unaffected by the knockdown of PGC-1? but it was impaired when PGC-1? expression was knockdown by the use of specific siRNA. Conclusions/Significance These results indicate that in white adipose tissue PGC-1? is dispensable for basal and rosiglitazone-induced mitochondrial biogenesis but required for the rosiglitazone-induced expression of UCP1 and other brown adipocyte-specific markers. Our study suggests that PGC-1? is important for the appearance of brown adipocytes in white adipose tissue. Our findings also provide evidence that PGC-1? and not PGC-1? regulates basal and rosiglitazone-induced mitochondrial gene expression in white adipocytes. PMID:22087241

Pardo, Rosario; Enguix, Natŕlia; Lasheras, Jaime; Feliu, Juan E.; Kralli, Anastasia; Villena, Josep A.

2011-01-01

156

Toward a Consensus on the Operation of Receptor-Induced Calcium Entry Signals  

NSDL National Science Digital Library

Receptor-induced Ca2+ signals involve both Ca2+ release from intracellular stores and extracellular Ca2+ entry across the plasma membrane. The channels mediating Ca2+ entry and the mechanisms controlling their function remain largely a mystery. Here we critically assess current views on the Ca2+ entry process and consider certain modifications to the widely held hypothesis that Ca2+ store emptying is the fundamental trigger for receptor-induced Ca2+ entry channels. Under physiological conditions, receptor-induced store depletion may be quite limited. A number of distinct channel activities appear to mediate receptor-induced Ca2+ entry, and their activation is observed to occur through quite diverse coupling processes.

Donald L. Gill (University of Maryland School of Medicine;Department of Biochemistry and Molecular Biology REV); Randen L. Patterson (Pennsylvania State University;Mueller Laboratory REV)

2004-07-27

157

Increased sensitivity to triiodothyronine (T3) of broiler lines with a high susceptibility for ascites.  

PubMed

1. In the studies reported here, broiler lines divergently selected for susceptibility to ascites under low temperature conditions were tested for their sensitivity to 3,3',5-triiodothyronine (T3) with respect to growth rate, rate of mortality, plasma concentrations of T3, right ventricular hypertrophy (RVH) and incidence of ascites. 2. Mean body weight of the ascites-susceptible line (BC-line) was higher than that of the ascites-resistant line (A-line). Adding 0.5 mg T3/kg of the diet depressed growth rate to the same extent in both lines. The effect of T3 on growth was more pronounced for males than for females. 3. T3-supplementation increased the relative weight of the heart and the incidence of RVH to the same extent in both lines. More of the T3-treated BC-line chickens had fluid accumulation in the abdominal cavity than the T3-treated A-line chickens. 4. Dietary T3-treatment depressed the plasma concentration of growth hormone (GH) profoundly and insulin-like growth factor (IGF-I) slightly but to the same extent in both lines. The coefficient of variation of GH concentrations indicate that T3 treatment mainly decreased GH-pulsatility in young growing broilers. 5. Higher doses of dietary T3 (1 and 2 mg/kg) increased mortality in a dose-dependent manner. With 2 mg T3/kg, mortality in the BC-line was almost double that in the A-line. 6. These studies indicate that the development of ascites could be linked with thyroid function. Moreover, dietary T3 supplementation could be used to help identify ascites-inducing factors or genetic lines with differential sensitivity for ascites. PMID:8062112

Decuypere, E; Vega, C; Bartha, T; Buyse, J; Zoons, J; Albers, G A

1994-05-01

158

Mineralocorticoid Receptor Agonists Induce Mouse Aortic Aneurysm Formation and Rupture in the Presence of High Salt  

PubMed Central

Objective Elevated plasma aldosterone concentrations in patients have been linked to a spectrum of cardiovascular diseases. Mineralocorticoid receptor antagonists provide additional benefits in heart failure patients. However, whether aldosterone and the mineralocorticoid receptor are involved in aortic aneurysm is unknown. Approach and Results We report that administration of deoxycorticosterone acetate (DOCA) and salt or aldosterone and salt, but not DOCA or salt alone, to C57BL/6 male mice induced abdominal and thoracic aortic aneurysm formation and rupture in an age-dependent manner. DOCA and salt or aldosterone and salt induced aortic aneurysm mimicked human aortic aneurysm with respect to elastin degradation, inflammatory cell infiltration, smooth muscle cell degeneration and apoptosis, and oxidative stress. Aortic aneurysm formation did not correlate with the increase in blood pressure induced by DOCA and salt. Systemic administration of the angiotensin converting enzyme inhibitor, enalapril, or angiotensin type 1 receptor antagonist, losartan, did not affect DOCA and salt induced aortic aneurysm. In contrast, the mineralocorticoid receptor antagonists, spironolactone or eplerenone, significantly attenuated DOCA and salt or aldosterone and salt induced aortic aneurysm. Conclusions The current study describes a novel aortic aneurysm animal model induced by mineralocorticoid receptor agonist and high salt, and reveals a previously unrecognized but potentially significant role of aldosterone in the pathogenesis of aortic aneurysm. These findings imply that mineralocorticoid receptor antagonists may be effective in the treatment of some aortic aneurysms. PMID:23661677

Liu, Shu; Xie, Zhongwen; Daugherty, Alan; Cassis, Lisa A.; Pearson, Kevin J.; Gong, Ming C.; Guo, Zhenheng

2013-01-01

159

Enhancement of D2 receptor agonist-induced inhibition by D1 receptor agonist in the ventral tegmental area.  

PubMed Central

1. A microiontophoretic study was performed on chloral hydrate-anaesthetized rats to examine the role of D1 receptors in the ventral tegmental area (VTA) neurones, which are inhibited by autoreceptor and D2 receptor agonists. 2. Inhibition by microiontophoretic application of quinpirole (a D2 agonist) of antidromic spikes elicited by stimulation of the nucleus accumbens in dopaminergic neurones of the VTA, was significantly enhanced by simultaneous application of SKF 38393 (D1 agonist), although SKF 38393 alone had little effect on the neurones. 3. In addition, quinpirole-induced inhibition was antagonized by iontophoretic application of domperidone (D2 antagonist), but was not affected by SCH 23390 (D1 antagonist). 4. Furthermore, SKF 38393-induced enhancement of inhibition by quinpirole was antagonized by simultaneous application of SCH 23390. 5. These results suggest that activation of D1 receptors located on the VTA dopaminergic neurones or on non-dopaminergic nerve terminals is not essential for inducing inhibition of the dopaminergic neurones, but enhances D2 receptor-mediated inhibition directly or indirectly via inhibitory neurones. Images Figure 1 PMID:7902179

Momiyama, T.; Sasa, M.; Takaori, S.

1993-01-01

160

Roles of parathyroid hormone (PTH) receptor and reactive oxygen species in hyperlipidemia-induced PTH resistance in preosteoblasts.  

PubMed

Bioactive lipids initiate inflammatory reactions leading to pathogenesis of atherosclerosis. Evidence shows that they also contribute to bone loss by inhibiting parathyroid hormone receptor (PTH1R) expression and differentiation of osteoblasts. We previously demonstrated that bone anabolic effects of PTH(1-34) are blunted in hyperlipidemic mice and that these PTH effects are restored by antioxidants. However, it is not clear which osteoblastic cell developmental stage is targeted by bioactive lipids. To investigate the effects of hyperlipidemia at the cellular level, hyperlipidemic Ldlr(-/-) mice were bred with Col3.6GFPtpz mice, in which preosteoblasts/osteoblasts carry a topaz fluorescent label, and with Col2.3GFPcyan mice, in which more mature osteoblasts/osteocytes carry a cyan fluorescent label. Histological analyses of trabecular bone surfaces in femoral as well as calvarial bones showed that intermittent PTH(1-34) increased fluorescence intensity in WT-Tpz mice, but not in Tpz-Ldlr(-/-) mice. In contrast, PTH(1-34) did not alter fluorescence intensity in femoral cortical envelopes of either WT-Cyan or Ldlr(-/-)-Cyan mice. To test the mechanism of PTH1R downregulation, preosteoblastic MC3T3-E1 cells were treated with bioactive lipids and the antioxidant Trolox. Results showed that inhibitory effects of PTH1R levels by bioactive lipids were rescued by pretreatment with Trolox. The inhibitory effects on expression of PTH1R as well as on PTH-induced osteoblastic genes were mimicked by xanthine/xanthine oxidase, a known generator of reactive oxygen species. These findings suggest an important role of the preosteoblastic development stage as the target and downregulation of PTH receptor expression mediated by intracellular oxidant stress as a mechanism in hyperlipidemia-induced PTH resistance. PMID:24038594

Li, Xin; Garcia, Jamie; Lu, Jinxiu; Iriana, Sidney; Kalajzic, Ivo; Rowe, David; Demer, Linda L; Tintut, Yin

2014-01-01

161

An extract of Lagerstroemia speciosa L. has insulin-like glucose uptake-stimulatory and adipocyte differentiation-inhibitory activities in 3T3-L1 cells.  

PubMed

The effects of extracts isolated from Lagerstroemia speciosa L. (banaba) on glucose transport and adipocyte differentiation in 3T3-L1 cells were studied. Glucose uptake-inducing activity of banaba extract (BE) was investigated in differentiated adipocytes using a radioactive assay, and the ability of BE to induce differentiation in preadipocytes was examined by Northern and Western blot analyses. The hot water BE and the banaba methanol eluent (BME) stimulated glucose uptake in 3T3-L1 adipocytes with an induction time and a dose-dependent response similar to those of insulin. Furthermore, there were no additive or synergistic effects found between BE and insulin on glucose uptake, and the glucose uptake activity of insulin could be reduced to basal levels by adding increasing amounts of BE. Unlike insulin, BE did not induce adipocyte differentiation in the presence of 3-isobutyl-1-methylxanthine (IBMX) and dexamethasone (DEX). BE inhibited the adipocyte differentiation induced by insulin plus IBMX and DEX (IS-IBMX-DEX) of 3T3-L1 preadipocytes in a dose-dependent manner. The differences in the glucose uptake and differentiation inhibitory activities between untreated cells and those treated with BE were significant (P < 0.01). The inhibitory activity was further demonstrated by drastic reductions of peroxisome proliferator-activated receptor gamma2 (PPARgamma2) mRNA and glucose transporter-4 (GLUT4) protein in cells induced from preadipocytes with IS-IBMX-DEX in the presence of BE. The unique combination of a glucose uptake stimulatory activity, the absence of adipocyte differentiation activity and effective inhibition of adipocyte differentiation induced by IS-IBMX-DEX in 3T3-L1 cells suggest that BE may be useful for prevention and treatment of hyperglycemia and obesity in type II diabetics. PMID:11533261

Liu, F; Kim, J; Li, Y; Liu, X; Li, J; Chen, X

2001-09-01

162

Auxiliary GABAB receptor subunits uncouple G protein ?? subunits from effector channels to induce desensitization.  

PubMed

Activation of K(+) channels by the G protein ?? subunits is an important signaling mechanism of G-protein-coupled receptors. Typically, receptor-activated K(+) currents desensitize in the sustained presence of agonists to avoid excessive effects on cellular activity. The auxiliary GABAB receptor subunit KCTD12 induces fast and pronounced desensitization of the K(+) current response. Using proteomic and electrophysiological approaches, we now show that KCTD12-induced desensitization results from a dual interaction with the G protein: constitutive binding stabilizes the heterotrimeric G protein at the receptor, whereas dynamic binding to the receptor-activated G?? subunits induces desensitization by uncoupling G?? from the effector K(+) channel. While receptor-free KCTD12 desensitizes K(+) currents activated by other GPCRs in vitro, native KCTD12 is exclusively associated with GABAB receptors. Accordingly, genetic ablation of KCTD12 specifically alters GABAB responses in the brain. Our results show that GABAB receptors are endowed with fast and reversible desensitization by harnessing KCTD12 that intercepts G?? signaling. PMID:24836506

Turecek, Rostislav; Schwenk, Jochen; Fritzius, Thorsten; Ivankova, Klara; Zolles, Gerd; Adelfinger, Lisa; Jacquier, Valerie; Besseyrias, Valerie; Gassmann, Martin; Schulte, Uwe; Fakler, Bernd; Bettler, Bernhard

2014-06-01

163

Differentiation-inducing agents decrease cryptic prolactin receptors in cultured rat mammary tumor cells.  

PubMed

Normal proliferating and neoplastic mammary cells in culture have cryptic prolactin receptors. These cryptic sites represent 80-95% of the total receptors and can be unmasked by energy depletion. Since lactating mammary tissue and other prolactin targets do not contain cryptic receptors, we have suggested that these sites may be important in the growth response to prolactin. In this study, therefore, we determined the effects of dimethylsulfoxide (DMSO) and sodium butyrate, two inducers of differentiation in other cell systems, on primary cultures of 7,12-dimethylbenzanthracene-induced rat mammary tumors. These substances decreased cryptic receptor levels and inhibited growth. Sodium butyrate (5 mM) decreased receptor levels within 3 h; by 24 h, receptor levels averaged 11 +/- 3% of the controls (n = 13). Similarly, DMSO (1-5%) caused a dose-dependent decrease in receptor levels. With 4% DMSO, there was a progressive decrease in prolactin binding to a nadir of 22 +/- 6% of the controls (n = 8) at 12-24 h. Receptor levels returned to pretreatment values by 24 h after the removal of sodium butyrate or DMSO. In addition, sodium butyrate and DMSO increased the formation of the multicellular structures called 'domes' and the accumulation of lipid droplets. Since sodium butyrate and DMSO decreased cryptic sites, inhibited cell growth and evoked the expression of some morphologic features of differentiation, we conclude that the loss of cryptic prolactin receptors may be involved in the acquisition of a differentiated phenotype in mammary cells. PMID:6092117

Costlow, M E

1984-11-01

164

Conformational toggle switches implicated in basal constitutive and agonist-induced activated states of 5-hydroxytryptamine-4 receptors.  

PubMed

The extended classic ternary complex model predicts that a G protein-coupled receptor (GPCR) exists in only two interconvertible states: an inactive R, and an active R(*). However, different structural active R(*) complexes may exist in addition to a silent inactive R ground state (Rg). Here we demonstrate, in a cellular context, that several R(*) states of 5-hydroxytryptamine-4 (5-HT(4)) receptors involve different side-chain conformational toggle switches. Using site-directed mutagenesis and molecular modeling approaches, we show that the basal constitutive receptor (R(*)basal) results from stabilization of an obligatory double toggle switch (Thr3.36 from inactive g- to active g+ and Trp6.48 from inactive g+ to active t). Mutation of either threonine or tryptophan to alanine resulted in a lowering of the activity of the R(*)basal similar to the Rg. The T3.36A mutation shows that the Thr3.36 toggle switch plays a minor role in the stabilization of R(*) induced by 5-HT (R(*)-5-HT) and BIMU8 (R(*)-BIMU8) and is fully required in the stabilization of R(*) induced by (S)-zacopride, cisapride, and 1-(4-amino-5-chloro-2-methoxyphenyl)-3-(1-butyl-4-piperidinyl)-1-propanone (RS 67333) (R(*)-benzamides). Thus, benzamides stabilize R(*)-benzamides by forming a specific hydrogen bond with Thr3.36 in the active g+ conformation. Conversely, R(*)-BIMU8 was probably the result of a direct conformational transition of Trp6.48 from inactive g+ to active t by hydrogen bonding of this residue to a carboxyl group of BIMU8. We were surprised that the Trp6.48 toggle switch was not necessary for receptor activation by the natural agonist 5-HT. R(*)-5-HT is probably attained through other routes of activation. Thus, different conformational arrangements occur during stabilization of R(*)basal, R(*)-5-HT, R(*)-benzamides, and R(*)-BIMU8. PMID:19168624

Pellissier, Lucie P; Sallander, Jessica; Campillo, Mercedes; Gaven, Florence; Queffeulou, Emilie; Pillot, Marion; Dumuis, Aline; Claeysen, Sylvie; Bockaert, Joël; Pardo, Leonardo

2009-04-01

165

The triple neurokinin-receptor antagonist CS003 inhibits neurokinin A-induced bronchoconstriction in patients with asthma  

Microsoft Academic Search

Neurokinin A (NKA) causes bronchoconstriction in asthmatic patients. In vitro both NK1 and NK2 receptors can mediate airway contraction. Moreover in guinea pigs, NK3 receptors facilitate cholinergic neurotransmission. Dual tachykinin NK1\\/NK2 receptor antagonism results in prevention of NKA-induced bronchoconstriction. We have now examined the effect of a single dose of the triple tachykinin receptor antagonist CS-003 on NKA-induced bronchoconstriction in

V. Schelfhout; R. Louis; W. Lenz; R. Heyrman; R. Pauwels; G. Joos

2006-01-01

166

Peripheral P2X7 receptor-induced mechanical hyperalgesia is mediated by bradykinin.  

PubMed

P2X7 receptors play an important role in inflammatory hyperalgesia, but the mechanisms involved in their hyperalgesic role are not completely understood. In this study, we hypothesized that P2X7 receptor activation induces mechanical hyperalgesia via the inflammatory mediators bradykinin, sympathomimetic amines, prostaglandin E2 (PGE2), and pro-inflammatory cytokines and via neutrophil migration in rats. We found that 2'(3')-O-(4-benzoylbenzoyl)adenosine 5'-triphosphate triethylammonium salt (BzATP), the most potent P2X7 receptor agonist available, induced a dose-dependent mechanical hyperalgesia that was blocked by the P2X7 receptor-selective antagonist A-438079 but unaffected by the P2X1,3,2/3 receptor antagonist TNP-ATP. These findings confirm that, although BzATP also acts at both P2X1 and P2X3 receptors, BzATP-induced hyperalgesia was mediated only by P2X7 receptor activation. Co-administration of selective antagonists of bradykinin B1 (Des-Arg(8)-Leu(9)-BK (DALBK)) or B2 receptors (bradyzide), ?1 (atenolol) or ?2 adrenoceptors (ICI 118,551), or local pre-treatment with the cyclooxygenase inhibitor indomethacin or the nonspecific selectin inhibitor fucoidan each significantly reduced BzATP-induced mechanical hyperalgesia in the rat hind paw. BzATP also induced the release of the pro-inflammatory cytokines tumor necrosis factor ? (TNF-?), interleukin (IL)-1?, IL-6 and cytokine-induced neutrophil chemoattractant-1 (CINC-1), an effect that was significantly reduced by A-438079. Co-administration of DALBK or bradyzide with BzATP significantly reduced BzATP-induced IL-1? and CINC-1 release. These results indicate that peripheral P2X7 receptor activation induces mechanical hyperalgesia via inflammatory mediators, especially bradykinin, which may contribute to pro-inflammatory cytokine release. These pro-inflammatory cytokines in turn may mediate the contributions of PGE2, sympathomimetic amines and neutrophil migration to the mechanical hyperalgesia induced by local P2X7 receptor activation. PMID:24997266

Teixeira, J M; de Oliveira-Fusaro, M C G; Parada, C A; Tambeli, C H

2014-09-26

167

Functional Relevance of the Switch of VEGF Receptors/Co-Receptors during Peritoneal Dialysis-Induced Mesothelial to Mesenchymal Transition  

PubMed Central

Vascular endothelial growth factor (VEGF) is up-regulated during mesothelial to mesenchymal transition (MMT) and has been associated with peritoneal membrane dysfunction in peritoneal dialysis (PD) patients. It has been shown that normal and malignant mesothelial cells (MCs) express VEGF receptors (VEGFRs) and co-receptors and that VEGF is an autocrine growth factor for mesothelioma. Hence, we evaluated the expression patterns and the functional relevance of the VEGF/VEGFRs/co-receptors axis during the mesenchymal conversion of MCs induced by peritoneal dialysis. Omentum-derived MCs treated with TGF-?1 plus IL-1? (in vitro MMT) and PD effluent-derived MCs with non-epithelioid phenotype (ex vivo MMT) showed down-regulated expression of the two main receptors Flt-1/VEGFR-1 and KDR/VEGFR-2, whereas the co-receptor neuropilin-1 (Nrp-1) was up-regulated. The expression of the Nrp-1 ligand semaphorin-3A (Sema-3A), a functional VEGF competitor, was repressed throughout the MMT process. These expression pattern changes were accompanied by a reduction of the proliferation capacity and by a parallel induction of the invasive capacity of MCs that had undergone an in vitro or ex vivo MMT. Treatment with neutralizing anti-VEGF or anti-Nrp-1 antibodies showed that these molecules played a relevant role in cellular proliferation only in naďve omentum-derived MCs. Conversely, treatment with these blocking antibodies, as well as with recombinant Sema-3A, indicated that the switched VEGF/VEGFRs/co-receptors axis drove the enhanced invasion capacity of MCs undergoing MMT. In conclusion, the expression patterns of VEGFRs and co-receptors change in MCs during MMT, which in turn would determine their behaviour in terms of proliferation and invasion in response to VEGF. PMID:23585849

Perez-Lozano, Maria Luisa; Sandoval, Pilar; Rynne-Vidal, Angela; Aguilera, Abelardo; Jimenez-Heffernan, Jose Antonio; Albar-Vizcaino, Patricia; Majano, Pedro L.; Sanchez-Tomero, Jose Antonio; Selgas, Rafael; Lopez-Cabrera, Manuel

2013-01-01

168

NADPH oxidase is the primary source of superoxide induced by NMDA receptor activation  

Microsoft Academic Search

Neuronal NMDA receptor (NMDAR) activation leads to the formation of superoxide, which normally acts in cell signaling. With extensive NMDAR activation, the resulting superoxide production leads to neuronal death. It is widely held that NMDA-induced superoxide production originates from the mitochondria, but definitive evidence for this is lacking. We evaluated the role of the cytoplasmic enzyme NADPH oxidase in NMDA-induced

Angela M Brennan; Sang Won Suh; Seok Joon Won; Purnima Narasimhan; Tiina M Kauppinen; Hokyou Lee; Ylva Edling; Pak H Chan; Raymond A Swanson

2009-01-01

169

Nck? Adapter Regulates Actin Polymerization in NIH 3T3 Fibroblasts in Response to Platelet-Derived Growth Factor bb  

PubMed Central

The SH3-SH3-SH3-SH2 adapter Nck represents a two-gene family that includes Nck? (Nck) and Nck? (Grb4/Nck2), and it links receptor tyrosine kinases to intracellular signaling networks. The function of these mammalian Nck genes has not been established. We report here a specific role for Nck? in platelet-derived growth factor (PDGF)-induced actin polymerization in NIH 3T3 cells. Overexpression of Nck? but not Nck? blocks PDGF-stimulated membrane ruffling and formation of lamellipoda. Mutation in either the SH2 or the middle SH3 domain of Nck? abolishes its interfering effect. Nck? binds at Tyr-1009 in human PDGF receptor ? (PDGFR-?) which is different from Nck?'s binding site, Tyr-751, and does not compete with phosphatidylinositol-3 kinase for binding to PDGFR. Microinjection of an anti-Nck? but not an anti-Nck? antibody inhibits PDGF-stimulated actin polymerization. Constitutively membrane-bound Nck? but not Nck? blocks Rac1-L62-induced membrane ruffling and formation of lamellipodia, suggesting that Nck? acts in parallel to or downstream of Rac1. This is the first report of Nck?'s role in receptor tyrosine kinase signaling to the actin cytoskeleton. PMID:11027258

Chen, Min; She, Hongyun; Kim, Airie; Woodley, David T.; Li, Wei

2000-01-01

170

Angiotensin Type 1 Receptor Blockers Induce Peroxisome Proliferator-Activated Receptor Activity  

Microsoft Academic Search

Background—Angiotensin type 1 receptor (AT1R) blockers (ARB) have been shown to reduce the incidence of type 2 diabetes mellitus by an unknown molecular mechanism. The peroxisome proliferator-activated receptor- (PPAR )i s the central regulator of insulin and glucose metabolism improving insulin sensitivity. We investigated the regulation of PPAR function by ARBs. Methods and Results—The ARBs irbesartan and telmisartan (10 mol\\/L)

Michael Schupp; Jürgen Janke; Ronald Clasen; Thomas Unger; Ulrich Kintscher

171

Cigarette smoke-induced CXCR3 receptor up-regulation mediates endothelial apoptosis.  

PubMed

Endothelial monocyte-activating polypeptide II (EMAP II) and interferon-inducible protein (IP)-10 are proinflammatory mediators, which in addition to their chemokine activities, selectively induce apoptosis in endothelial cells and are up-regulated in the lungs of cigarette smoke-exposed humans. Previously, we showed that EMAP II is an essential mediator of cigarette smoke-induced lung emphysema in mice linking endothelial cell apoptosis with inflammation. Here we addressed the role of the CXCR3 receptor in EMAP II-induced and IP-10-induced apoptosis in endothelial cells and its regulation by cigarette smoke. We found that both neutralizing antibodies and small inhibitory RNA to CXCR3 abrogated EMAP II-induced and IP-10-induced endothelial caspase-3 activation and DNA fragmentation. CXCR3 receptor surface expression in human lung microvascular endothelial cells and in lung tissue endothelium was up-regulated by exposure to cigarette smoke. In tissue culture conditions, EMAP II-induced and IP-10-induced apoptosis was enhanced by preincubation with cigarette smoke extract. Interestingly, serum starvation also induced CXCR3 up-regulation and enhanced EMAP II-induced endothelial apoptosis. Signal transduction via p38 mitogen-activated protein kinase activation was essential for CXCR3-induced cell death, but not for CXCR3 receptor up-regulation by cigarette smoke. In turn, protein nitration was required for CXCR3 receptor up-regulation by cigarette smoke and consequently for subsequent CXCR3-induced cell death. In conclusion, the concerted up-regulation of proinflammatory EMAP II, IP-10, and CXCR3 by cigarette smoke could sustain a cascade of cell death that may promote the alveolar tissue loss noted in human emphysema. PMID:22936405

Green, Linden A; Petrusca, Daniela; Rajashekhar, Gangaraju; Gianaris, Tom; Schweitzer, Kelly S; Wang, Liang; Justice, Matthew J; Petrache, Irina; Clauss, Matthias

2012-12-01

172

Endothelin-stimulated Ca2+ mobilization by 3T3-L1 adipocytes is suppressed by tumor necrosis factor-alpha.  

PubMed

The cytokine tumor necrosis factor-alpha (TNFalpha) contributes to metabolic changes in disease states such as insulin resistance. However, the mechanism by which TNFalpha alters cellular function in these conditions is poorly understood. Because changes in intracellular calcium concentration plays a critical role in hormone action we investigated the effect of TNFalpha on calcium homeostasis in 3T3-L1 adipocytes. In these studies we show that TNFalpha causes a concentration- and time-dependent decrease in Na+/myo-inositol cotransporter (SMIT) mRNA levels and myo-inositol accumulation as well as a decrease in myo-inositol incorporation into phosphoinositides. These changes coincided with a decrease in endothelin-1-induced phosphatidylinositol (PI) cycle activity in 3T3-L1 adipocytes chronically exposed to TNFalpha. Endothelin-1-induced mobilization of calcium from intracellular stores was also diminished by TNFalpha. The effect of TNFalpha on endothelin-1-induced PI cycle activity and calcium mobilization was not due to a decrease in endothelin receptors. However, TNFalpha did cause a moderate decrease in phosphatidylinositol 4,5-bisphosphate (PIP2)-specific phospholipase C (PLC) activity in 3T3-L1 adipocytes. Combined, a decrease in phosphoinositide production and PIP2-specific PLC activity could be responsible for altering PI cycle activity and the generation of the second messenger myo-inositol 1,4,5-trisphosphate, thereby reducing calcium mobilization. Such changes in intracellular signaling may contribute to the pathophysiology of insulin resistance associated with TNFalpha. PMID:9882452

Yorek, M; Jaipaul, N; Dunlap, J; Bielefeldt, K

1999-01-15

173

Involvement of NMDA receptor in low-frequency magnetic field-induced anxiety in mice.  

PubMed

Abstract It had been reported that exposure to extremely low-frequency magnetic field (ELFMF) induces anxiety in human and rodents. Anxiety mediates via the activation of N-methyl-d-aspartate (NMDA) receptor, whereas activation of ?-aminobutyric acid (GABA) receptor attenuates the same. Hence, the present study was carried out to understand the contribution of NMDA and/or GABA receptors modulation in ELFMF-induced anxiety for which Swiss albino mice were exposed to ELFMF (50?Hz, 10?G) by subjecting them to Helmholtz coils. The exposure was for 8?h/day for 7, 30, 60, 90 and 120 days. Anxiety level was assessed in elevated plus maze, open field test and social interaction test, on 7th, 30th, 60th, 90th and 120th exposure day, respectively. Moreover, the role of GABA and glutamate in ELFMF-induced anxiety was assessed by treating mice with muscimol [0.25?mg/kg intraperitoneally (i.p.)], bicuculline (1.0?mg/kg i.p.), NMDA (15?mg/kg i.p.) and MK-801 (0.03?mg/kg i.p.), as a GABAA and NMDA receptor agonist and antagonist, respectively. Glutamate receptor agonist exacerbated while inhibitor attenuated the ELFMF-induced anxiety. In addition, levels of GABA and glutamate were determined in regions of the brain viz, cortex, striatum, hippocampus and hypothalamus. Experiments demonstrated significant elevation of GABA and glutamate levels in the hippocampus and hypothalamus. However, GABA receptor modulators did not produce significant effect on ELFMF-induced anxiety and elevated levels of GABA at tested dose. Together, these findings suggest that ELFMF significantly induced anxiety behavior, and indicated the involvement of NMDA receptor in its effect. PMID:24131395

Salunke, Balwant P; Umathe, Sudhir N; Chavan, Jagatpalsingh G

2014-12-01

174

Modest hypoxia significantly reduces triglyceride content and lipid droplet size in 3T3-L1 adipocytes  

SciTech Connect

Highlights: •Long-term hypoxia decreased the size of LDs and lipid storage in 3T3-L1 adipocytes. •Long-term hypoxia increased basal lipolysis in 3T3-L1 adipocytes. •Hypoxia decreased lipid-associated proteins in 3T3-L1 adipocytes. •Hypoxia decreased basal glucose uptake and lipogenic proteins in 3T3-L1 adipocytes. •Hypoxia-mediated lipogenesis may be an attractive therapeutic target against obesity. -- Abstract: Background: A previous study has demonstrated that endurance training under hypoxia results in a greater reduction in body fat mass compared to exercise under normoxia. However, the cellular and molecular mechanisms that underlie this hypoxia-mediated reduction in fat mass remain uncertain. Here, we examine the effects of modest hypoxia on adipocyte function. Methods: Differentiated 3T3-L1 adipocytes were incubated at 5% O{sub 2} for 1 week (long-term hypoxia, HL) or one day (short-term hypoxia, HS) and compared with a normoxia control (NC). Results: HL, but not HS, resulted in a significant reduction in lipid droplet size and triglyceride content (by 50%) compared to NC (p < 0.01). As estimated by glycerol release, isoproterenol-induced lipolysis was significantly lowered by hypoxia, whereas the release of free fatty acids under the basal condition was prominently enhanced with HL compared to NC or HS (p < 0.01). Lipolysis-associated proteins, such as perilipin 1 and hormone-sensitive lipase, were unchanged, whereas adipose triglyceride lipase and its activator protein CGI-58 were decreased with HL in comparison to NC. Interestingly, such lipogenic proteins as fatty acid synthase, lipin-1, and peroxisome proliferator-activated receptor gamma were decreased. Furthermore, the uptake of glucose, the major precursor of 3-glycerol phosphate for triglyceride synthesis, was significantly reduced in HL compared to NC or HS (p < 0.01). Conclusion: We conclude that hypoxia has a direct impact on reducing the triglyceride content and lipid droplet size via decreased glucose uptake and lipogenic protein expression and increased basal lipolysis. Such an hypoxia-induced decrease in lipogenesis may be an attractive therapeutic target against lipid-associated metabolic diseases.

Hashimoto, Takeshi, E-mail: thashimo@fc.ritsumei.ac.jp [Faculty of Sport and Health Science, Ritsumeikan University, 1-1-1 Nojihigashi, Kusatsu, Shiga 525-8577 (Japan)] [Faculty of Sport and Health Science, Ritsumeikan University, 1-1-1 Nojihigashi, Kusatsu, Shiga 525-8577 (Japan); Yokokawa, Takumi; Endo, Yuriko [Faculty of Sport and Health Science, Ritsumeikan University, 1-1-1 Nojihigashi, Kusatsu, Shiga 525-8577 (Japan)] [Faculty of Sport and Health Science, Ritsumeikan University, 1-1-1 Nojihigashi, Kusatsu, Shiga 525-8577 (Japan); Iwanaka, Nobumasa [Ritsumeikan Global Innovation Research Organization, Ritsumeikan University, 1-1-1 Nojihigashi, Kusatsu, Shiga 525-8577 (Japan)] [Ritsumeikan Global Innovation Research Organization, Ritsumeikan University, 1-1-1 Nojihigashi, Kusatsu, Shiga 525-8577 (Japan); Higashida, Kazuhiko [Faculty of Sport and Health Science, Ritsumeikan University, 1-1-1 Nojihigashi, Kusatsu, Shiga 525-8577 (Japan) [Faculty of Sport and Health Science, Ritsumeikan University, 1-1-1 Nojihigashi, Kusatsu, Shiga 525-8577 (Japan); Faculty of Sport Science, Waseda University, 2-579-15 Mikajima, Tokorozawa, Saitama 359-1192 (Japan); Taguchi, Sadayoshi [Faculty of Sport and Health Science, Ritsumeikan University, 1-1-1 Nojihigashi, Kusatsu, Shiga 525-8577 (Japan)] [Faculty of Sport and Health Science, Ritsumeikan University, 1-1-1 Nojihigashi, Kusatsu, Shiga 525-8577 (Japan)

2013-10-11

175

Fractalkine and Its Receptor, CX3CR1, Upregulation in Streptozotocin-Induced Diabetic Kidneys  

Microsoft Academic Search

Background: Fractalkine is induced on activated endothelial cells and promotes strong adhesion of T cells and monocytes via its receptor CX3CR1. In kidney, fractalkine expression might be induced by high shear stress and play an important role in prolonged glomerular diseases. We examined whether fractalkine and CX3CR1 upregulation are found in streptozotocin-induced diabetic kidneys. Methods: Diabetic rats were randomized to

Yuichi Kikuchi; Ryota Ikee; Noriaki Hemmi; Naomi Hyodo; Takamitsu Saigusa; Tamehachi Namikoshi; Muneharu Yamada; Shigenobu Suzuki; Soichiro Miura

2004-01-01

176

Expression of Fractalkine (CX3CL1) and Its Receptor in Endotoxin-Induced Uveitis  

Microsoft Academic Search

Background\\/Aims: Chemokines play a critical role in inflammation and neurodegenerative disease in the central nervous system. In this study, endotoxin-induced uveitis (EIU) was induced to test the expression of fractalkine, a special neuronal chemokine, and its receptor CX3CR1 in acute inflammation of the retina. Methods:EIU was induced by footpad injections of lipopolysaccharide (LPS). Eight rats were sacrificed at each time

Liqun Chu; Xiaoxin Li; Wenzen Yu; Tong Qian; Huijun Qi; Luzhen Huang; Yongsheng Xu

2009-01-01

177

Suppression of Niacin-induced Vasodilation with an Antagonist to Prostaglandin D2 Receptor Subtype 1  

Microsoft Academic Search

Niacin (nicotinic acid) reduces cardiovascular events in patients with dyslipidemia. However, symptoms associated with niacin-induced vasodilation (e.g., flushing) have limited its use. Laropiprant is a selective antagonist of the prostaglandin D2 receptor subtype 1 (DP1), which may mediate niacin-induced vasodilation. The aim of this proof-of-concept study was to evaluate the effects of laropiprant (vs placebo) on niacin-induced cutaneous vasodilation. Coadministration

E Lai; I De Lepeleire; T M Crumley; F Liu; L A Wenning; N Michiels; E Vets; G O'Neill; J A Wagner; K Gottesdiener

2007-01-01

178

Paronychia induced by the epidermal growth factor receptor inhibitor cetuximab.  

PubMed

While the development of epidermal growth factor receptor inhibitors has been hailed as a remarkable triumph in the field of oncology, it has inherited with it a host of cutaneous side-effects that have been increasingly observed in a substantial number of patients in the recent years. One cutaneous manifestation that may inflict significant pain and affect activities of daily living among some of the patients receiving epidermal growth factor receptor inhibitors is paronychia. A case of paronychia associated with the use of cetuximab in the management of KRAS wild-type midrectal adenocarcinoma along with its management has been described. PMID:23161875

Lee, Soo Lin; Tan, Boon Seang; Chan, Lee Chin

2013-09-01

179

The platelet fibrinogen receptor: an immunogold-surface replica study of agonist-induced ligand binding and receptor clustering  

PubMed Central

Platelet aggregation requires the binding of fibrinogen to its receptor, a heterodimer consisting of the plasma-membrane glycoproteins (GP) IIb and IIIa. Although the GPIIb-IIIa complex is present on the surface of unstimulated platelets, it binds fibrinogen only after platelet activation. We have used an immunogold-surface replica technique to study the distribution of GPIIb-IIIa and bound fibrinogen over broad areas of surface membranes in unstimulated, as well as thrombin-activated and ADP-activated human platelets. We found that the immunogold-labeled GPIIb-IIIa was monodispersed over the surface of unstimulated platelets, although the cell surface lacked immunoreactive fibrinogen. On thrombin-stimulated platelets, approximately 65% of the GPIIb-IIIa molecules were in clusters within the plane of the membrane. Fibrinogen, which had been released from the alpha-granules of these cells, bound to GPIIb-IIIa on the cell surface and was similarly clustered. To determine whether the receptors clustered before ligand binding, or as a consequence thereof, we studied the surface distribution of GPIIb-IIIa after stimulation with ADP, which causes activation of the fibrinogen receptor function of GPIIb-IIIa without inducing the release of fibrinogen. In the absence of added fibrinogen, the unoccupied, yet binding-competent receptors on ADP-stimulated platelets were monodispersed. The addition of fibrinogen caused the GPIIb-IIIa molecules to cluster on the cell surface. Clustering was also induced by the addition of the GPIIb-IIIa-binding domains of fibrinogen, namely the tetrapeptide Arg-Gly-Asp-Ser on the alpha-chain or the gamma-chain decapeptide gamma 402-411. These results show that receptor occupancy causes clustering of GPIIb-IIIa in activated platelets. PMID:3584243

1987-01-01

180

Triiodothyronine (T3) stimulates food intake via enhanced hypothalamic AMP-activated kinase activity  

Microsoft Academic Search

Thyroid hormone regulates food intake. We previously reported that rats with triiodothyronine (T3)-induced thyrotoxicosis display hyperphagia associated with suppressed circulating leptin levels, increased hypothalamic neuropeptide Y (NPY) mRNA and decreased hypothalamic pro-opiomelanocortin (POMC) mRNA. AMP-activated kinase (AMPK) is a serine\\/threonine protein kinase that is activated when cellular energy is depleted. We hypothesized that T3 causes an increase in hypothalamic AMPK

Shinya Ishii; Jun Kamegai; Hideki Tamura; Takako Shimizu; Hitoshi Sugihara; Shinichi Oikawa

2008-01-01

181

Bombesin Stimulation of DNA Synthesis and Cell Division in Cultures of Swiss 3T3 Cells  

Microsoft Academic Search

Bombesin is shown to be a potent mitogen for Swiss 3T3 cells. At nanomolar concentrations the peptide markedly enhances the ability of fresh serum to stimulate DNA synthesis in confluent and quiescent cultures of these cells. In the presence of a low concentration (3.5%) of serum, bombesin stimulates 3T3 cell proliferation. In serum-free medium, bombesin induces DNA synthesis in the

Enrique Rozengurt; James Sinnett-Smith

1983-01-01

182

Dual Roles for Endothelin-B Receptors in Modulating Adjuvant-Induced Inflammatory Hyperalgesia in Rats.  

PubMed

Injection of endothelin-1 (ET-1) into the plantar rat hindpaw causes acute pain at high concentrations and tactile sensitization at low concentrations. The pro-nociceptive actions are driven through ET(A) receptors for both levels of [ET-1], but the ET(B) receptors are only pro-nociceptive for allodynia from low [ET-1] and anti-nociceptive for pain from high [ET-1]. The goal of the present work was to discriminate the roles of the ET receptors in the acute hyperalgesia from inflammation by complete Freund's adjuvant (CFA, 20 mg/paw) into the rat hindpaw. Selective antagonists were injected l0 min before and then together with CFA. An ET(A) receptor antagonist, BQ-123, reduced CFA-induced thermal hyperalgesia (by up to 50%), as did an ET(B) receptor antagonist, BQ-788 (by up to 66%). BQ-123 and BQ-788 also delayed the onset (by 1.5 - 2 h) but insignificantly reduced the maximum degree of CFA-induced allodynia (~10%). Surprisingly, an ET(B) receptor agonist, IRL-1620, also reduced maximum thermal hyperalgesia induced by CFA, suppressed peak allodynia and delayed its occurrence by ~ 3 h. The latter actions of IRL-1620 were reversed by co-administration of BQ-788, naloxone hydrochloride and the peripherally restricted opiate receptor antagonist naloxone methiodide, and by antiserum against ?-endorphin. These findings demonstrate an important role for endogenous ET-1 in acute inflammatory pain and a dual action of ET(B) receptors, including a pro-algesic action along with the important activation of a local analgesic pathway, implying that at least two different ET(B) receptors contribute to modulation of inflammatory pain. PMID:20559459

Khodorova, Alla; Zou, Shiping; Ren, Ke; Dubner, Ronald; Davar, Gudarz; Strichartz, Gary

2009-01-01

183

Dual Roles for Endothelin-B Receptors in Modulating Adjuvant-Induced Inflammatory Hyperalgesia in Rats  

PubMed Central

Injection of endothelin-1 (ET-1) into the plantar rat hindpaw causes acute pain at high concentrations and tactile sensitization at low concentrations. The pro-nociceptive actions are driven through ETA receptors for both levels of [ET-1], but the ETB receptors are only pro-nociceptive for allodynia from low [ET-1] and anti-nociceptive for pain from high [ET-1]. The goal of the present work was to discriminate the roles of the ET receptors in the acute hyperalgesia from inflammation by complete Freund's adjuvant (CFA, 20 mg/paw) into the rat hindpaw. Selective antagonists were injected l0 min before and then together with CFA. An ETA receptor antagonist, BQ-123, reduced CFA-induced thermal hyperalgesia (by up to 50%), as did an ETB receptor antagonist, BQ-788 (by up to 66%). BQ-123 and BQ-788 also delayed the onset (by 1.5 – 2 h) but insignificantly reduced the maximum degree of CFA-induced allodynia (~10%). Surprisingly, an ETB receptor agonist, IRL-1620, also reduced maximum thermal hyperalgesia induced by CFA, suppressed peak allodynia and delayed its occurrence by ~ 3 h. The latter actions of IRL-1620 were reversed by co-administration of BQ-788, naloxone hydrochloride and the peripherally restricted opiate receptor antagonist naloxone methiodide, and by antiserum against ?-endorphin. These findings demonstrate an important role for endogenous ET-1 in acute inflammatory pain and a dual action of ETB receptors, including a pro-algesic action along with the important activation of a local analgesic pathway, implying that at least two different ETB receptors contribute to modulation of inflammatory pain. PMID:20559459

Khodorova, Alla; Zou, Shiping; Ren, Ke; Dubner, Ronald; Davar, Gudarz; Strichartz, Gary

2010-01-01

184

Curcumin prevents corticosterone-induced neurotoxicity and abnormalities of neuroplasticity via 5-HT receptor pathway.  

PubMed

Curcumin, a major active component of Curcuma longa, possesses antioxidant and neuroprotective activities. The present study explores the mechanisms underlying the neuroprotective effect of curcumin against corticosterone and its relation to 5-hydroxy tryptamine (5-HT) receptors. Exposure of cortical neurons to corticosterone results in decreased mRNA levels for three 5-HT receptor subtypes, 5-HT(1A), 5-HT(2A) and 5-HT(4), but 5-HT(1B,) 5-HT(2B), 5-HT(2C), 5-HT(6) and 5-HT(7) receptors remain unchanged. Pre-treatment with curcumin reversed this effect on mRNA for the 5-HT(1A) and 5-HT(4) receptors, but not for the 5-HT(2A) receptor. Moreover, curcumin exerted a neuroprotective effect against corticosterone-induced neuronal death. This observed effect of curcumin was partially blocked by either 5-HT(1A) receptor antagonist p-MPPI or 5-HT(4) receptor antagonist RS 39604 alone; whereas, the simultaneous application of both antagonists completely reversed the effect. Curcumin was also found to regulate corticosterone-induced morphological changes such as increases in soma size, dendritic branching and dendritic spine density, as well as elevate synaptophysin expression in cortical neurons. p-MPPI and RS 39604 reversed the effect of curcumin-induced change in neuronal morphology and synaptophysin expression of corticosterone-treated neurons. In addition, an increase in cyclic adenosine monophosphate (cAMP) level was observed after curcumin treatment, which was further prevented by RS 39604, but not by p-MPPI. However, curcumin-induced elevation in protein kinase A activity and phosphorylation of cAMP response element-binding protein levels were inhibited by both p-MPPI and RS 39604. These findings suggest that the neuroprotection and modulation of neuroplasticity exhibited by curcumin might be mediated, at least in part, via the 5-HT receptor-cAMP-PKA-CREB signal pathway. PMID:21689105

Xu, Ying; Li, Shan; Vernon, Matthew M; Pan, Jianchun; Chen, Ling; Barish, Philip A; Zhang, Yuan; Acharya, Abhinav P; Yu, Jie; Govindarajan, Subramaniam S; Boykin, Erin; Pan, Xiaoyu; O'Donnell, James M; Ogle, William O

2011-09-01

185

The Lymphotoxin-? Receptor Induces Different Patterns of Gene Expression via Two NF-?B Pathways  

Microsoft Academic Search

The lymphotoxin-? receptor (LT?R) plays critical roles in inflammation and lymphoid organogenesis through activation of NF-?B. In addition to activation of the classical NF-?B, ligation of this receptor induces the processing of the cytosolic NF-?B2\\/p100 precursor to yield the mature p52 subunit, followed by translocation of p52 to the nucleus. This activation of NF-?B2 requires NIK and IKK?, while NEMO\\/IKK?

Emmanuel Dejardin; Nathalie M. Droin; Mireille Delhase; Elvira Haas; Yixue Cao; Constantin Makris; Zhi-Wei Li; Michael Karin; Carl F. Ware; Douglas R. Green

2002-01-01

186

Ionotropic and Metabotropic Glutamate Receptor Antagonism Attenuates Cue-Induced Cocaine Seeking  

Microsoft Academic Search

Neuroanatomical and pharmacological evidence implicates glutamate transmission in drug-environment conditioning that partly controls drug seeking and relapse. Glutamate receptors could be targets for pharmacological attenuation of the motivational properties of drug-paired cues and for relapse prevention. The purpose of the present study was therefore to investigate the involvement of ionotropic and metabotropic glutamate receptor subtypes in cue-induced reinstatement of cocaine-seeking

Pia Bäckström; Petri Hyytiä

2006-01-01

187

Homotypic FADD interactions through a conserved RXDLL motif are required for death receptor-induced apoptosis  

Microsoft Academic Search

Death receptors in the TNF receptor superfamily signal for apoptosis via the ordered recruitment of FADD and caspase-8 to a death-inducing signaling complex (DISC). However, the nature of the protein–protein interactions in the signaling complex is not well defined. Here we show that FADD self-associates through a conserved RXDLL motif in the death effector domain (DED). Despite exhibiting similar binding

J R Muppidi; A A Lobito; M Ramaswamy; J K Yang; L Wang; H Wu; R M Siegel

2006-01-01

188

Activation of dopamine D3 receptors inhibits reward-related learning induced by cocaine  

Microsoft Academic Search

Memories of learned associations between the rewarding properties of drugs and environmental cues contribute to craving and relapse in humans. The mesocorticolimbic dopamine (DA) system is involved in reward-related learning induced by drugs of abuse. DA D3 receptors are preferentially expressed in mesocorticolimbic DA projection areas. Genetic and pharmacological studies have shown that DA D3 receptors suppress locomotor-stimulant effects of

H. Kong; W. Kuang; S. Li; M. Xu

2011-01-01

189

Wen-pi-tang-Hab-Wu-ling-san, a Polyherbal Medicine, Attenuates ER Stress in 3T3-L1 Preadipocytes by Promoting the Insulin Signaling Pathway  

PubMed Central

The endoplasmic reticulum (ER) is an organelle that functions to synthesize, fold, and transport proteins. ER stress is a key link between type 2 diabetes (T2D), obesity, and insulin resistance. In this study, we investigated the effect of WHW on the ER stress response and the insulin signaling pathway in 3T3-L1 preadipocytes. 3T3-L1 preadipocytes were differentiated into adipocytes, and ER stress was then induced by treatment with tunicamycin. ER stress-induced adipocytes were treated with different concentrations of WHW for 24?h. The expression of ER stress-related molecules such as X-box-binding protein-1 (XBP-1), glucose-regulated protein 78 (GRP78), C/EBP-homologous protein 10 (CHOP10), and eukaryotic initiation factor 2? (eIF2?) and signaling molecules such as phosphatidylinositol 3-kinase (PI3K), insulin receptor substrates-1 (IRS-1), and c-Jun N-terminal protein kinase (JNK) were investigated. WHW significantly inhibited the expression of XBP-1, GRP78, CHOP10, and eIF2? in ER stress-induced 3T3-L1 adipocytes. WHW also increased the PI3K expression and the IRS-1 phosphorylation but decreased the phosphorylation of JNK in ER stress-induced 3T3-L1 adipocytes. Our results indicate that WHW inhibits ER stress in adipocytes by suppressing the expression of ER stress-mediated molecules and the insulin signaling pathway, suggesting that WHW may be an attractive therapeutic agent for managing T2D. PMID:24454515

Han, Yunkyung; Jung, Hyo Won; Bae, Hyo Sang; Park, Yong-Ki

2013-01-01

190

Wen-pi-tang-Hab-Wu-ling-san, a Polyherbal Medicine, Attenuates ER Stress in 3T3-L1 Preadipocytes by Promoting the Insulin Signaling Pathway.  

PubMed

The endoplasmic reticulum (ER) is an organelle that functions to synthesize, fold, and transport proteins. ER stress is a key link between type 2 diabetes (T2D), obesity, and insulin resistance. In this study, we investigated the effect of WHW on the ER stress response and the insulin signaling pathway in 3T3-L1 preadipocytes. 3T3-L1 preadipocytes were differentiated into adipocytes, and ER stress was then induced by treatment with tunicamycin. ER stress-induced adipocytes were treated with different concentrations of WHW for 24?h. The expression of ER stress-related molecules such as X-box-binding protein-1 (XBP-1), glucose-regulated protein 78 (GRP78), C/EBP-homologous protein 10 (CHOP10), and eukaryotic initiation factor 2 ? (eIF2 ? ) and signaling molecules such as phosphatidylinositol 3-kinase (PI3K), insulin receptor substrates-1 (IRS-1), and c-Jun N-terminal protein kinase (JNK) were investigated. WHW significantly inhibited the expression of XBP-1, GRP78, CHOP10, and eIF2 ? in ER stress-induced 3T3-L1 adipocytes. WHW also increased the PI3K expression and the IRS-1 phosphorylation but decreased the phosphorylation of JNK in ER stress-induced 3T3-L1 adipocytes. Our results indicate that WHW inhibits ER stress in adipocytes by suppressing the expression of ER stress-mediated molecules and the insulin signaling pathway, suggesting that WHW may be an attractive therapeutic agent for managing T2D. PMID:24454515

Han, Yunkyung; Jung, Hyo Won; Bae, Hyo Sang; Park, Yong-Ki

2013-01-01

191

Therapeutics Based On The Induced Internalization Of Surface Receptors  

Cancer.gov

The National Cancer Institute, Laboratory of Cellular Oncology is seeking statements of capability or interest from parties interested in collaborative research to further develop, evaluate, or commercialize therapeutics for diseases or conditions associated with target receptors, such as cancer, angiogenesis, or HIV infections.

192

Epac, not PKA catalytic subunit, is required for 3T3-L1 preadipocyte differentiation  

PubMed Central

Cyclic AMP plays a critical role in adipocyte differentiation and maturation. However, it is not clear which of the two intracellular cAMP receptors, exchange protein directly activated by cAMP/cAMP-regulated guanine nucleotide exchange factor or protein kinase A/cAMP-dependent protein kinase, is essential for cAMP-mediated adipocyte differentiation. In this study, we utilized a well-defined adipose differentiation model system, the murine preadipocyte line 3T3-L1, to address this issue. We showed that knocking down Epac expression in 3T3-L1 cells using lentiviral based small hairpin RNAs down-regulated peroxisome proliferator-activated receptor gamma expression and dramatically inhibited adipogenic conversion of 3T3-L1 cells while inhibiting PKA catalytic subunit activity by two mechanistically distinct inhibitors, heat stable protein kinase inhibitor and H89, had no effect on 3T3-L1 adipocyte differentiation. Moreover, cAMP analog selectively activating Epac was not able to stimulate adipogenic conversion. Our study demonstrated that while PKA catalytic activity is dispensable, activation of Epac is necessary but not sufficient for adipogenic conversion of 3T3-L1 cells. PMID:20036887

Ji, Zhenyu; Mei, Fang C.; Cheng, Xiaodong

2009-01-01

193

Peripheral adenosine A2A receptors are involved in carrageenan-induced mechanical hyperalgesia in mice.  

PubMed

Here we studied the role of peripheral adenosine A(2A) receptors in mechanical hyperalgesia during inflammation using mice lacking the A(2A) receptors. Unilateral s.c. administration of the local inflammatory agent ?-carrageenan induced profound mechanical hyperalgesia 24 h after administration in the ipsilateral hind paw in wild-type mice. In homozygous mice lacking the A(2A) receptors, carrageenan-induced hyperalgesia was significantly reduced compared to wild type controls. The reduction in inflammatory hyperalgesia seen in A(2A) receptor knock-out mice was not associated with changes in paw edema. CGS 21680, a selective A(2A) receptor agonist, produced significantly more mechanical hyperalgesia in wild type females than in wild type males upon direct s.c. injection into the hindpaw whereas it had no effect upon systemic administration. The hyperalgesic effect of CGS 21680 was markedly reduced in the A(2A) knock-out mice of both sexes. Subcutaneous ZM-241,385, a selective A(2A) receptor antagonist, injected into the hindpaw reduced the mechanical hyperalgesia following carrageenan in female mice, but not in males. The results indicate that activation of peripheral adenosine A(2A) receptors during inflammation is associated with mechanical hyperalgesia, and that this effect is more prominent in females than in males. PMID:20678550

Li, L; Hao, J X; Fredholm, B B; Schulte, G; Wiesenfeld-Hallin, Z; Xu, X J

2010-10-27

194

Muscarinic M? receptors contribute to allergen-induced airway remodeling in mice.  

PubMed

Asthma is a chronic obstructive airway disease, characterized by inflammation and remodeling. Acetylcholine contributes to symptoms by inducing bronchoconstriction via the muscarinic M3 receptor. Recent evidence suggests that bronchoconstriction can regulate airway remodeling, and therefore implies a role for the muscarinic M3 receptor. The objective of this work was to study the contribution of the muscarinic M3 receptor to allergen-induced remodeling using muscarinic M3 receptor subtype-deficient (M3R(-/-)) mice. Wild-type (WT), M1R(-/-), and M2R(-/-) mice were used as controls. C57Bl/6 mice were sensitized and challenged with ovalbumin (twice weekly for 4 wk). Control animals were challenged with saline. Allergen exposure induced goblet cell metaplasia, airway smooth muscle thickening (1.7-fold), pulmonary vascular smooth muscle remodeling (1.5-fold), and deposition of collagen I (1.7-fold) and fibronectin (1.6-fold) in the airway wall of WT mice. These effects were absent or markedly lower in M3R(-/-) mice (30-100%), whereas M1R(-/-) and M2R(-/-) mice responded similarly to WT mice. In addition, airway smooth muscle and pulmonary vascular smooth muscle mass were 35-40% lower in saline-challenged M3R(-/-) mice compared with WT mice. Interestingly, allergen-induced airway inflammation, assessed as infiltrated eosinophils and T helper type 2 cytokine expression, was similar or even enhanced in M3R(-/-) mice. Our data indicate that acetylcholine contributes to allergen-induced remodeling and smooth muscle mass via the muscarinic M3 receptor, and not via M1 or M2 receptors. No stimulatory role for muscarinic M3 receptors in allergic inflammation was observed, suggesting that the role of acetylcholine in remodeling is independent of the allergic inflammatory response, and may involve bronchoconstriction. PMID:24156289

Kistemaker, Loes E M; Bos, Sophie T; Mudde, Willemieke M; Hylkema, Machteld N; Hiemstra, Pieter S; Wess, Jürgen; Meurs, Herman; Kerstjens, Huib A M; Gosens, Reinoud

2014-04-01

195

The Role of Purinergic Receptors in Cancer-Induced Bone Pain  

PubMed Central

Cancer-induced bone pain severely compromises the quality of life of many patients suffering from bone metastasis, as current therapies leave some patients with inadequate pain relief. The recent development of specific animal models has increased the understanding of the molecular and cellular mechanisms underlying cancer-induced bone pain including the involvement of ATP and the purinergic receptors in the progression of the pain state. In nociception, ATP acts as an extracellular messenger to transmit sensory information both at the peripheral site of tissue damage and in the spinal cord. Several of the purinergic receptors have been shown to be important for the development and maintenance of neuropathic and inflammatory pain, and studies have demonstrated the importance of both peripheral and central mechanisms. We here provide an overview of the current literature on the role of purinergic receptors in cancer-induced bone pain with emphasis on some of the difficulties related to studying this complex pain state. PMID:23091774

Falk, Sarah; Uldall, Maria; Heegaard, Anne-Marie

2012-01-01

196

Inhibitory signaling blocks activating receptor clustering and induces cytoskeletal retraction in natural killer cells  

PubMed Central

Natural killer (NK) lymphocytes use a variety of activating receptors to recognize and kill infected or tumorigenic cells during an innate immune response. To prevent targeting healthy tissue, NK cells also express numerous inhibitory receptors that signal through immunotyrosine-based inhibitory motifs (ITIMs). Precisely how signals from competing activating and inhibitory receptors are integrated and resolved is not understood. To investigate how ITIM receptor signaling impinges on activating pathways, we developed a photochemical approach for stimulating the inhibitory receptor KIR2DL2 during ongoing NK cell–activating responses in high-resolution imaging experiments. Photostimulation of KIR2DL2 induces the rapid formation of inhibitory receptor microclusters in the plasma membrane and the simultaneous suppression of microclusters containing activating receptors. This is followed by the collapse of the peripheral actin cytoskeleton and retraction of the NK cell from the source of inhibitory stimulation. These results suggest a cell biological basis for ITIM receptor signaling and establish an experimental framework for analyzing it. PMID:21339333

Abeyweera, Thushara P.; Merino, Ernesto

2011-01-01

197

Stress-induced alterations in 5-HT1A receptor transcriptional modulators NUDR and Freud-1.  

PubMed

The effect of stress on the mRNA and protein level of the 5-HT1A receptor and two of its key transcriptional modulators, NUDR and Freud-1, was examined in the prefrontal cortex (PFC) and hippocampus (Hp) using rodent models: olfactory bulbectomy (OB) and prenatal stress (PS) in male and female rats; chronic mild stress in male rats (CMS) and pregnancy stress. In PFC, CMS induced the most widespread changes, with significant reduction in both mRNA and protein levels of NUDR, 5-HT1A receptor and in Freud-1 mRNA; while in Hp 5-HT1A receptor and Freud-1 protein levels were also decreased. In male, but not female OB rats PFC Freud-1 and 5-HT1A receptor protein levels were reduced, while in Hp 5-HT1A receptor, Freud-1 and NUDR mRNA's but not protein were reduced. In PS rats PFC 5-HT1A receptor protein was reduced more in females than males; while in Hp Freud-1 protein was increased in females. In pregnancy stress, PFC NUDR, Freud-1 and 5-HT1A protein receptor levels were reduced, and in HP 5-HT1A receptor protein levels were also reduced; in HP only NUDR and Freud-1 mRNA levels were reduced. Overall, CMS and stress during pregnancy produced the most salient changes in 5-HT1A receptor and transcription factor expression, suggesting a primary role for altered transcription factor expression in chronic regulation of 5-HT1A receptor expression. By contrast, OB (in males) and PS (in females) produced gender-specific reductions in PFC 5-HT1A receptor protein levels, suggesting a role for post-transcriptional regulation. These and previous data suggest that chronic stress might be a key regulator of NUDR/Freud-1 gene expression. PMID:24946016

Szewczyk, Bernadeta; Kotarska, Katarzyna; Daigle, Mireille; Misztak, Paulina; Sowa-Kucma, Magdalena; Rafalo, Anna; Curzytek, Katarzyna; Kubera, Marta; Basta-Kaim, Agnieszka; Nowak, Gabriel; Albert, Paul R

2014-11-01

198

Ligand-Induced Alterations in the Phosphorylation State of Ethylene Receptors in Tomato Fruit1[W][OA  

E-print Network

Ligand-Induced Alterations in the Phosphorylation State of Ethylene Receptors in Tomato Fruit1[W fully determined. Here we demonstrate that LeETR4, a critical receptor for tomato (Solanum lycopersicum in tomato fruits. We provide insights into the nature of receptor on and off states. The gaseous plant

Klee, Harry J.

199

Transgenic analysis reveals that thyroid hormone receptor is sufficient to mediate the thyroid hormone signal in frog metamorphosis.  

PubMed

Thyroid hormone (T3) has long been known to be important for vertebrate development and adult organ function. Whereas thyroid hormone receptor (TR) knockout and transgenic studies of mice have implicated TR involvement in mammalian development, the underlying molecular bases for the resulting phenotypes remain to be determined in vivo, especially considering that T3 is known to have both genomic, i.e., through TRs, and nongenomic effects on cells. Amphibian metamorphosis is an excellent model for studying the role of TR in vertebrate development because of its total dependence on T3. Here we investigated the role of TR in metamorphosis by developing a dominant positive mutant thyroid hormone receptor (dpTR). In the frog oocyte transcription system, dpTR bound a T3-responsive promoter and activated the promoter independently of T3. Transgenic expression of dpTR under the control of a heat shock-inducible promoter in premetamorphic tadpoles led to precocious metamorphic transformations. Molecular analyses showed that dpTR induced metamorphosis by specifically binding to known T3 target genes, leading to increased local histone acetylation and gene activation, similar to T3-bound TR during natural metamorphosis. Our experiments indicated that the metamorphic role of T3 is through genomic action of the hormone, at least on the developmental parameters tested. They further provide the first example where TR is shown to mediate directly and sufficiently these developmental effects of T3 in individual organs by regulating target gene expression in these organs. PMID:15456876

Buchholz, Daniel R; Tomita, Akihiro; Fu, Liezhen; Paul, Bindu D; Shi, Yun-Bo

2004-10-01

200

Fluoroquinolones reduce carrageenan-induced edema in rats and the involvement of the glucocorticoid receptor system.  

PubMed

We studied the effect of fluoroquinolones (FQs) on carrageenan-induced edema in the rat footpad. Ciprofloxacin, gatifloxacin, sparfloxacin, norfloxacin, and enoxacin (s.c., 100 mg/kg), which have piperazinyl and/or cyclopropyl groups, inhibited carrageenan-induced edema, whereas levofloxacin, tosufloxacin, and pazufloxacin did not. The reduction of edema by ciprofloxacin, sparfloxacin, and enoxacin was abolished by pretreatment with mifepristone, an antagonist of the glucocorticoid receptor. These results suggest that FQs with piperazinyl and/or cyclopropyl groups can modify biological responses through enhancing the glucocorticoid-glucocorticoid receptor system. PMID:19396522

Ogino, Hiromi; Yamada, Kaori; Yuhara, Mizuki; Tsuchida, Saori; Maezawa, Kayoko; Kizu, Junko; Hori, Seiji

2009-04-01

201

Metabotropic Glutamate Receptors Modulate the NMDA and AMPA-Induced Gene Expression in Neocortical  

Microsoft Academic Search

Group I metabotropic glutamate receptors (mGluRIs) can be colocal- izedwithionotropicglutamatereceptorsinpostsynapticmembranes. We have investigated whether mGluRIs alter the gene transcription induced by N-methyl-D-aspartate (NMDA) and (S)-a-amino-3- hydroxy-5-methyl-4-isoxazolpropionic acid (AMPA) receptors in rat neocortical g-aminobutyric acid (GABA) interneurons. In cultures of dissociated interneurons, the mGluRI antagonists LY367385 and MPEP reduced the increase in phosphorylation of the transcription factor CREB induced by NMDA

Kerstin Lindemeyer; Jost Leemhuis; Steffen Loffler; Nina Grass; Wolfgang Norenberg; Dieter K. Meyer

202

Endothelial Cell-specific Deficiency of AngII Type 1a Receptors Attenuates AngII-induced Ascending Aortic Aneurysms in LDL Receptor ?/? Mice  

PubMed Central

Rationale Human studies and mouse models have provided evidence for angiotensin II (AngII)-based mechanisms as an underlying cause of aneurysms localized to the ascending aorta. In agreement with this associative evidence, we have published recently that AngII infusion induces aneurysmal pathology in the ascending aorta. Objective The aim of this study was to define the role of angiotensin II type 1a (AT1a) receptors and their cellular location in AngII-induced ascending aortic aneurysms (AAs). Methods and Results Male LDL receptor ?/? mice were fed a saturated fat-enriched diet for 1 week prior to osmotic mini-pump implantation and infused with either saline or AngII (1,000 ng/kg/min) for 28 days. Intimal surface areas of ascending aortas were measured to quantify ascending AAs. Whole body AT1a receptor deficiency ablated AngII-induced ascending AAs (P<0.001). To determine the role of AT1a receptors on leukocytes, LDL receptor ?/? x AT1a receptor +/+ or ?/? mice were irradiated and repopulated with bone marrow-derived cells isolated from either AT1a receptor +/+ or ?/? mice. Deficiency of AT1a receptors in bone marrow-derived cells had no effect on AngII-induced ascending AAs. To determine the role of AT1a receptors on vascular wall cells, we developed AT1a receptor floxed mice with depletion on either smooth muscle (SMC) or endothelial cells using Cre driven by either SM22 or Tek, respectively. AT1a receptor deletion in SMCs had no effect on ascending AAs. In contrast, endothelial-specific depletion attenuated this pathology. Conclusions AngII infusion promotes aneurysms in the ascending aorta via stimulation of AT1a receptors that are expressed on endothelial cells. PMID:21252156

Rateri, Debra L.; Moorleghen, Jessica J.; Balakrishnan, Anju; Owens, A. Phillip; Howatt, Deborah A.; Subramanian, Venkateswaran; Poduri, Aruna; Charnigo, Richard; Cassis, Lisa A.; Daugherty, Alan

2011-01-01

203

GLP-1 receptor agonist-induced polyarthritis: a case report.  

PubMed

Occasional cases of bilateral, symmetrical, seronegative polyarthritis have been reported in patients treated with dipeptidyl peptidase-4 inhibitors (Crickx et al. in Rheumatol Int, 2013). We report here a similar case observed during treatment with a GLP-1 receptor agonist. A 42-year-old man with type 2 diabetes treated with metformin 1,500 mg/day and liraglutide 1.8 mg/day. After 6 months from the beginning of treatment, the patient complained of bilateral arthralgia (hands, feet, ankles, knees, and hips). Erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), and leukocytes were increased. Rheumatoid factor, anticyclic citrullinated protein antibody, antinuclear antibodies, anti-Borrelia, and burgdorferi antibodies were all negative, and myoglobin and calcitonin were normal. Liraglutide was withdrawn, and the symptoms completely disappeared within 1 week, with normalization of ESR, CRP, fibrinogen, and leukocytes. Previously described cases of polyarthritis associated with DPP4 inhibitors had been attributed to a direct effect of the drugs on inflammatory cells expressing the enzyme. The present case, occurred during treatment with a GLP-1 receptor agonists, suggests a possibly different mechanism, mediated by GLP-1 receptor stimulation, which deserved further investigation. PMID:24158775

Ambrosio, Maria Luisa; Monami, Matteo; Sati, Lavinia; Marchionni, Niccolň; Di Bari, Mauro; Mannucci, Edoardo

2014-08-01

204

SCFAs Induce Mouse Neutrophil Chemotaxis through the GPR43 Receptor  

PubMed Central

Short chain fatty acids (SCFAs) have recently attracted attention as potential mediators of the effects of gut microbiota on intestinal inflammation. Some of these effects have been suggested to occur through the direct actions of SCFAs on the GPR43 receptor in neutrophils, though the precise role of this receptor in neutrophil activation is still unclear. We show that mouse bone marrow derived neutrophils (BMNs) can chemotax effectively through polycarbonate filters towards a source of acetate, propionate or butyrate. Moreover, we show that BMNs move with good speed and directionality towards a source of propionate in an EZ-Taxiscan chamber coated with fibrinogen. These effects of SCFAs were mimicked by low concentrations of the synthetic GPR43 agonist phenylacetamide-1 and were abolished in GPR43?/? BMNs. SCFAs and phenylacetamide-1 also elicited GPR43-dependent activation of PKB, p38 and ERK and these responses were sensitive to pertussis toxin, indicating a role for Gi proteins. Phenylacetamide-1 also elicited rapid and transient activation of Rac1/2 GTPases and phosphorylation of ribosomal protein S6. Genetic and pharmacological intervention identified important roles for PI3K?, Rac2, p38 and ERK, but not mTOR, in GPR43-dependent chemotaxis. These results identify GPR43 as a bona fide chemotactic receptor for neutrophils in vitro and start to define important elements in its signal transduction pathways. PMID:21698257

Vinolo, Marco A. R.; Ferguson, G. John; Kulkarni, Suhasini; Damoulakis, George; Anderson, Karen; Bohlooly-Y, Mohammad

2011-01-01

205

Significance of the progesterone receptor and epidermal growth factor receptor, but not the estrogen receptor, in chemically induced lung carcinogenesis in female A/J mice  

PubMed Central

In the present study, the expression levels of female hormone receptors, estrogen receptor (ER) and progesterone receptor (PR) and the epidermal growth factor receptor, (EGFR), as well as proliferating cell nuclear antigen (PCNA) were examined in lung tumors that were induced by 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) in female A/J mice. Each seven-week-old mouse was administered with 2 mg NNK via intraperitoneal injection and the mice were subsequently euthanized at week 52. Lung tumors, including adenomas, carcinomas in adenomas and adenocarcinomas, were obtained and analyzed by immunohistochemistry for the expression levels of the receptors, ER, PR and EGFR, and PCNA. The results were as follows: i) In mouse lung adenomas, a significant correlation was identified between the size of the tumor and PCNA expression, although not with the expression of the receptors (ER, PR and EGFR); ii) in the carcinoma components of the carcinomas in adenomas, the size of the tumor and PCNA expression were correlated, while EGFR expression demonstrated a significant correlation with PR expression; iii) in adenocarcinomas, the tumor size significantly correlated with PCNA, EGFR and PR expression; and iv) EGFR and PR expression was identified to be significantly correlated in adenocarcinomas, and to a certain extent in the carcinoma components of the carcinomas in adenomas, although not in the adenomas. Notably, ER expression was not associated with tumor growth or the other factors, particularly EGFR expression, and no significant differences were identified between the three types of lesion. These results indicate that PR, like EGFR, may be significant in lung carcinogenesis. PMID:25364399

KISHI, SOSUKE; YOKOHIRA, MASANAO; YAMAKAWA, KEIKO; SAOO, KOUSUKE; IMAIDA, KATSUMI

2014-01-01

206

St. John's wort promotes adipocyte differentiation and modulates NF-?B activation in 3T3-L1 cells.  

PubMed

St. John's wort (SJW), or Hypericum perforatum, is a perennial herb that has been used in the treatment of depression in several countries. Though its therapeutic effect on depression has been extensively studied, its influence on metabolic syndrome is yet to be fully characterized. Therefore, we investigated the effect of SJW extract on adipocyte differentiation and its anti-inflammatory effects by using 3T3-L1 preadipocytes. Oil Red O staining indicated that SJW promotes adipocyte differentiation, while immunoblots indicated that SJW increases the expression of peroxisome proliferator activated receptor ? (PPAR?), a nuclear receptor regulating adipocyte differentiation, and adiponectin, an anti-inflammatory adipokine. Furthermore, the anti-inflammatory activity of SJW was demonstrated by its inhibition of the activation of nuclear factor-?B (NF-?B), an inflammatory transcription factor. Stimulation of mature 3T3-L1 adipocytes by tumor necrosis factor-? (TNF-?) decreased the expression of the NF-?B inhibitor I?B?, and increased its phosphorylation. Treatment with SJW further decreased the TNF-?-induced perturbation in I?B? expression and phosphorylation, which indicated that SJW mediated the inhibition of NF-?B activation. In addition, SJW decreased the TNF-?-induced increase in the mRNA levels of pro-inflammatory adipokines, interleukin-6 (IL-6), and monocyte chemoattractant protein-1 (MCP-1). Collectively, our results indicate that SJW treatment could promote adipocyte differentiation probably through its anti-inflammatory activity, which in turn suggests that SJW has the potential to minimize the risk factors of metabolic syndrome. PMID:24989005

Hatano, Tomoko; Sameshima, Yuka; Kawabata, Mami; Yamada, Shizuo; Shinozuka, Kazumasa; Nakabayashi, Toshikatsu; Mizuno, Hideya

2014-01-01

207

T3 and Triac inhibit leptin secretion and expression in brown and white rat adipocytes.  

PubMed

Leptin regulates appetite, inhibits food intake, and seems to increase energy expenditure. We investigated the effect of triiodothyroacetic acid (Triac), a metabolite of T3, which seems to be more thermogenic than T3, on leptin secretion and mRNA expression. Rat primary cultures of white and brown adipocytes were treated with increasing concentrations of Triac and T3. The effect of different types of serum and insulin concentrations was also tested. Serum inhibited leptin secretion and mRNA expression. Leptin secretion was also clearly inhibited by Triac and T3 in a dose-dependent manner and with similar potency. In the presence of norepinephrine (NE), Triac and T3 had a similar inhibitory effect, but the inhibition was almost complete in white adipocytes. Parallel results were found at the mRNA level, where Triac and T3 had similar inhibitory potency, both alone and with NE. We also show that insulin induced dose- and time-dependent increases in leptin secretion, reaching maximum levels at 0.5 and 3 nM insulin for white and brown adipocytes, respectively. Leptin secretion was higher in white than in brown adipocytes. The increases in leptin secretion were preceded by increases in leptin mRNA. In conclusion, these data demonstrate for the first time that Triac, like T3 and serum, inhibits leptin secretion and expression in white and brown adipocytes, whereas insulin has the opposite effect. PMID:15158754

Medina-Gomez, Gema; Calvo, Rosa-Maria; Obregón, Maria-Jesus

2004-06-01

208

Involvement of Opioid Receptors in Inhibition of Bladder Overactivity Induced by Foot Stimulation in Cats  

PubMed Central

Purpose We examined the role of opioid receptors in the inhibition of bladder overactivity induced by electrical stimulation of the foot. Materials and Methods Experiments were done in 6 cats under ?-chloralose anesthesia when the bladder was infused with saline or 0.25% acetic acid. Naloxone (1 mg/kg intravenously) was administered to block opioid receptors. To modulate reflex bladder activity electrical stimulation (5 Hz, 0.2 millisecond pulse width) was applied to the foot via skin surface electrodes at intensities of multiple times the threshold needed to induce observable toe movement. Results Acetic acid irritated the bladder, induced bladder overactivity and significantly decreased bladder capacity to a mean ± SE 25.3% ± 5.9% that of saline control capacity (p = 0.0001). Foot stimulation at 4T suppressed acetic acid induced bladder overactivity and significantly increased bladder capacity to 47.1% ± 5.9% of control (p = 0.0007). Naloxone did not significantly change bladder capacity during acetic acid irritation but it completely eliminated the inhibition of bladder overactivity induced by foot stimulation. Conclusions Results indicate that opioid receptors have an important role in foot afferent inhibition of bladder overactivity. This raises the possibility that opioid receptors might be used as a pharmacological target to enhance the efficacy of foot stimulation for inhibiting bladder overactivity. PMID:22819119

Tai, Changfeng; Ogagan, P. Dafe; Chen, Guoqing; Larson, Jeffrey A.; Shen, Bing; Wang, Jicheng; Roppolo, James R.; de Groat, William C.

2013-01-01

209

Hesperetin glucuronides induce adipocyte differentiation via activation and expression of peroxisome proliferator-activated receptor-?.  

PubMed

In previous reports, hesperidin, a flavonoid glucoside from citrus fruit, is hydrolyzed to hesperetin, an aglycone of hesperidin, and converted to the hesperetin glucuronides (H7-OG and H3'-OG) in vivo and depresses blood glucose levels. But there are no reports on the activity of hesperetin glucuronides. To determine the activity of hesperetin glucuronides, H7-OG and H3'-OG were synthesized and peroxisome proliferator-activated receptor-? (PPAR?) agonist activity was observed at 250 ?M. These glucuronides accelerated the differentiation of 3T3-L1 cells into adipocytes at 10 ?M. Furthermore, H7-OG showed additive effects in reporter gene assays and caused noncompetitive reactions in time-resolved fluorescence resonance energy transfer assays with a thiazolidinedione derivative. Our results indicated that hesperetin glucuronides activated PPAR?, accelerated adipocyte differentiation. PMID:25036134

Gamo, Kanae; Miyachi, Hiroyuki; Nakamura, Kayoko; Matsuura, Nobuyasu

2014-01-01

210

Human embryonic and induced pluripotent stem cells express TRAIL receptors and can be sensitized to TRAIL-induced apoptosis.  

PubMed

Death ligands and their tumor necrosis factor receptor (TNFR) family receptors are the best-characterized and most efficient inducers of apoptotic signaling in somatic cells. In this study, we analyzed whether these prototypic activators of apoptosis are also expressed and able to be activated in human pluripotent stem cells. We examined human embryonic stem cells (hESC) and human-induced pluripotent stem cells (hiPSC) and found that both cell types express primarily TNF-related apoptosis-inducing ligand (TRAIL) receptors and TNFR1, but very low levels of Fas/CD95. We also found that although hESC and hiPSC contain all the proteins required for efficient induction and progression of extrinsic apoptotic signaling, they are resistant to TRAIL-induced apoptosis. However, both hESC and hiPSC can be sensitized to TRAIL-induced apoptosis by co-treatment with protein synthesis inhibitors such as the anti-leukemia drug homoharringtonine (HHT). HHT treatment led to suppression of cellular FLICE inhibitory protein (cFLIP) and Mcl-1 expression and, in combination with TRAIL, enhanced processing of caspase-8 and full activation of caspase-3. cFLIP likely represents an important regulatory node, as its shRNA-mediated down-regulation significantly sensitized hESC to TRAIL-induced apoptosis. Thus, we provide the first evidence that, irrespective of their origin, human pluripotent stem cells express canonical components of the extrinsic apoptotic system and on stress can activate death receptor-mediated apoptosis. PMID:23806100

Vinarsky, Vladimir; Krivanek, Jan; Rankel, Liina; Nahacka, Zuzana; Barta, Tomas; Jaros, Josef; Andera, Ladislav; Hampl, Ales

2013-11-15

211

Activation of the D1 receptors inhibits the long-term potentiation in vivo induced by acute morphine administration through a D1-GluN2A interaction in the nucleus accumbens.  

PubMed

Dopamine D1-like receptors can modulate glutamate-mediated excitatory synaptic neurotransmission, but the underlying molecular mechanism remains elusive. Here, we report that acute in-vivo morphine administration induces the long-term potentiation (Mor-LTP) of field excitatory postsynaptic potentials at the prefrontal cortex-to-nucleus accumbens shell synapses, and this process requires the activation of GluN2A-containing N-methyl-D-aspartate receptors. This Mor-LTP is completely inhibited by the D1-like receptor agonist SKF81297, but not by the D2-like receptor agonist quinpirole. SKF81297-inhibited Mor-LTP is restored by pretreatment with the TAT-conjugated interfering peptide TAT-D1-t3, which is a synthetic blocker of the direct D1-GluN2A receptor interaction. These results indicate that the activation of D1 receptors modulates Mor-LTP by the direct D1-GluN2A interaction at the prefrontal cortex-to-nucleus accumbens shell synapses and might play a role in addiction-related plastic alterations. PMID:25121622

Zheng, Qiaohua; Liu, Zhiqiang; Wei, Chunling; Han, Jing; Liu, Yihui; Zhang, Xia; Ren, Wei

2014-10-22

212

Involvement of central TRPV1 receptors in pentylenetetrazole and amygdala-induced kindling in male rats.  

PubMed

Transient receptor potential vanilloid 1 (TRPV1) is a non-selective cation channel that is involved in modulation of diverse physiological processes. The role of this receptor in epilepsy has not been studied well. Therefore, we investigated the role of central TRPV1 receptors on the development of pentylenetetrazole (PTZ) and amygdala-induced kindling in rats. Male Wistar rats received subconvulsive dose of PTZ intraperitoneally, every other day. TRPV1 receptor agonist, OLDA and its antagonist, AMG-9810 were injected intracerebroventricularly 30 min prior to PTZ administration. In electrical kindling, stimulating and recording electrodes were implanted in the right amygdala of male rats. After kindling, the effect of TRPV1 receptor agonist or antagonist on afterdischarge duration (ADD), latency to the onset of bilateral forelimb clonuses (S4L) and duration of loss of equilibrium (stage 5 seizures, S5D) were measured. The results demonstrated that, OLDA at the doses of 0.01, 0.1 and 1 ?g/rat, significantly accelerated the incidence of all seizure stages, increased S5D and decreased S4L in the PTZ model of kindling. Also, in amygdala kindling, S5D and ADD were significantly reduced following the administration of AMG-9810. In contrast, OLDA significantly aggravated the indices of seizure in both models of epileptic seizure. This study demonstrated that central TRPV1 receptors may be involved in the development of electrical and PTZ-induced kindling. PMID:24577898

Shirazi, Mohsen; Izadi, Mahin; Amin, Masoud; Rezvani, Mohammad Ebrahim; Roohbakhsh, Ali; Shamsizadeh, Ali

2014-08-01

213

Dopamine receptors and the persistent neurovascular dysregulation induced by methamphetamine self-administration in rats.  

PubMed

Recently abstinent methamphetamine (Meth) abusers showed neurovascular dysregulation within the striatum. The factors that contribute to this dysregulation and the persistence of these effects are unclear. The current study addressed these knowledge gaps. First, we evaluated the brains of rats with a history of Meth self-administration following various periods of forced abstinence. Micro-computed tomography revealed a marked reduction in vessel diameter and vascular volume uniquely within the striatum between 1 and 28 days after Meth self-administration. Microvessels showed a greater impairment than larger vessels. Subsequently, we determined that dopamine (DA) D2 receptors regulated Meth-induced striatal vasoconstriction via acute noncontingent administration of Meth. These receptors likely regulated the response to striatal hypoxia, as hypoxia inducible factor 1? was elevated. Acute Meth exposure also increased striatal levels of endothelin receptor A and decreased neuronal nitric oxide synthase. Collectively, the data provide novel evidence that Meth-induced striatal neurovascular dysregulation involves DA receptor signaling that results in vasoconstriction via endothelin receptor A and nitric oxide signaling. As these effects can lead to hypoxia and trigger neuronal damage, these findings provide a mechanistic explanation for the selective striatal toxicity observed in the brains of Meth-abusing humans. PMID:25185214

Kousik, Sharanya M; Napier, T Celeste; Ross, Ryan D; Sumner, D Rick; Carvey, Paul M

2014-11-01

214

Opiate-induced constipation related to activation of small intestine opioid ?2-receptors  

PubMed Central

AIM: To investigate the role of opioid ?-receptor subtype in opiate-induced constipation (OIC). METHODS: The effect of loperamide on intestinal transit was investigated in mice. Ileum strips were isolated from 12-wk-old male BALB/c mice for identification of isometric tension. The ileum strips were precontracted with 1 ?mol/L acetylcholine (ACh). Then, decrease in muscle tone (relaxation) was characterized after cumulative administration of 0.1-10 ?mol/L loperamide into the organ bath, for a concentration-dependent study. Specific blockers or antagonists were used for pretreatment to compare the changes in loperamide-induced relaxation. RESULTS: In addition to the delay in intestinal transit, loperamide produced a marked relaxation in isolated ileum precontracted with ACh, in a dose-dependent manner. This relaxation was abolished by cyprodime, a selective opioid ?-receptor antagonist, but not modified by naloxonazine at a dose sufficient to block opioid ?-1 receptors. Also, treatment with opioid ?-1 receptor agonist failed to modify the muscle tone. Moreover, the relaxation by loperamide was attenuated by glibenclamide at a dose sufficient to block ATP-sensitive K+ (KATP) channels, and by protein kinase A (PKA) inhibitor, but was enhanced by an inhibitor of phosphodiesterase for cyclic adenosine monophosphate (cAMP). CONCLUSION: Loperamide induces intestinal relaxation by activation of opioid ?-2 receptors via the cAMP-PKA pathway to open KATP channels, relates to OIC. PMID:22493554

Chen, Wency; Chung, Hsien-Hui; Cheng, Juei-Tang

2012-01-01

215

Potentiation of G-Protein-Coupled Receptor-Induced MAP Kinase Activation by Exogenous EGF Receptors in SK-N-MC Neuroepithelioma Cells  

Microsoft Academic Search

Lysophosphatidic acid (LPA) and endothelin-1 (ET-1), two ligands for G-protein coupled receptors (GPCRs), induce activation of mitogen activated protein kinase (MAPK). Surprisingly, LPA and ET-1 did not induce MAPK activation in SK-N-MC neuroepithelioma cells, even though these GPCR ligands evoked a rapid, transient rise in intracellular free Ca2+concentration in these cells, indicating that SK-N-MC cells express functional LPA- and ET-1-receptors.

Arjan Buist; Leon G. J. Tertoolen; Jeroen den Hertog

1998-01-01

216

Caffeine and adenosine A 2a receptor antagonists prevent ?-amyloid (25–35)-induced cognitive deficits in mice  

Microsoft Academic Search

Consumption of caffeine, an adenosine receptor antagonist, was found to be inversely associated with the incidence of Alzheimer's disease. Moreover, caffeine protects cultured neurons against ?-amyloid-induced toxicity, an effect mimicked by adenosine A2A but not A1 receptor antagonists. We now tested if caffeine administration would prevent ?-amyloid-induced cognitive impairment in mice and if this was mimicked by A2A receptor blockade.

Oscar P. Dall'Igna; Paulo Fett; Marcio W. Gomes; Diogo O. Souza; Rodrigo A. Cunha; Diogo R. Lara

2007-01-01

217

A constitutively active dioxin/aryl hydrocarbon receptor induces stomach tumors  

NASA Astrophysics Data System (ADS)

The dioxin/aryl hydrocarbon receptor (AhR) functions as a ligand-activated transcription factor regulating transcription of a battery of genes encoding xenobiotic metabolizing enzymes. Known receptor ligands are environmental pollutants including polycyclic aromatic hydrocarbons and polychlorinated dioxins. Loss-of-function (gene-disruption) studies in mice have demonstrated that the AhR is involved in toxic effects of dioxins but have not yielded unequivocal results concerning the physiological function of the receptor. Gain-of-function studies therefore were performed to unravel the biological functions of the AhR. A constitutively active AhR expressed in transgenic mice reduced the life span of the mice and induced tumors in the glandular part of the stomach, demonstrating the oncogenic potential of the AhR and implicating the receptor in regulation of cell proliferation.

Andersson, Patrik; McGuire, Jacqueline; Rubio, Carlos; Gradin, Katarina; Whitelaw, Murray L.; Pettersson, Sven; Hanberg, Annika; Poellinger, Lorenz

2002-07-01

218

Hydrogen sulphide induces ? opioid receptor-dependent analgesia in a rodent model of visceral pain  

PubMed Central

Background Hydrogen sulphide (H2S) is a gaseous neuro-mediator that exerts analgesic effects in rodent models of visceral pain by activating KATP channels. A body of evidence support the notion that KATP channels interact with endogenous opioids. Whether H2S-induced analgesia involves opioid receptors is unknown. Methods The perception of painful sensation induced by colorectal distension (CRD) in conscious rats was measured by assessing the abdominal withdrawal reflex. The contribution of opioid receptors to H2S-induced analgesia was investigated by administering rats with selective ?, ? and ? opioid receptor antagonists and antisenses. To investigate whether H2S causes ? opioid receptor (MOR) transactivation, the neuronal like cells SKNMCs were challenged with H2S in the presence of MOR agonist (DAMGO) or antagonist (CTAP). MOR activation and phosphorylation, its association to ? arrestin and internalization were measured. Results H2S exerted a potent analgesic effects on CRD-induced pain. H2S-induced analgesia required the activation of the opioid system. By pharmacological and molecular analyses, a robust inhibition of H2S-induced analgesia was observed in response to central administration of CTAP and MOR antisense, while ? and ? receptors were less involved. H2S caused MOR transactivation and internalization in SKNMCs by a mechanism that required AKT phosphorylation. MOR transactivation was inhibited by LY294002, a PI3K inhibitor, and glibenclamide, a KATP channels blocker. Conclusions This study provides pharmacological and molecular evidence that antinociception exerted by H2S in a rodent model of visceral pain is modulated by the transactivation of MOR. This observation provides support for development of new pharmacological approaches to visceral pain. PMID:20540729

2010-01-01

219

Serotonin type-1A receptors modulate adolescent, cocaine-induced offensive aggression in hamsters  

Microsoft Academic Search

Hamsters repeatedly exposed to cocaine throughout adolescence display highly escalated offensive aggression compared to saline-treated littermates. Recently, we have shown that serotonin neural signaling and development play an important role in adolescent cocaine-induced offensive aggression. This study examined whether the adolescent cocaine-induced aggressive response was modulated by serotonin type 1A (5HT1A) receptors. To test this, adolescent male Syrian hamsters were

Irina Knyshevski; Lesley A. Ricci; Thomas E. McCann; Richard H. Melloni

2005-01-01

220

Rosiglitazone, peroxisome proliferator receptor-gamma agonist, ameliorates gentamicin-induced nephrotoxicity in rats  

Microsoft Academic Search

Nephrotoxicity is a major complication of gentamicin (GEN), which is widely used in the treatment of severe gram-negative\\u000a infections. Reactive oxygen spaces (ROS) are important mediators of gentamicin-induced nephrotoxicity. Peroxisome proliferator-activated\\u000a receptors (PPARs) have different activities including antioxidant properties. This study was performed to investigate the\\u000a protective role of PPAR-? agonist against GEN-induced nephrotoxicity. Male Wistar Albino rats were randomly

Emin Ozbek; Yusuf Ozlem Ilbey; Abdulmuttalip Simsek; Mustafa Cekmen; Fatih Mete; Adnan Somay

2010-01-01

221

5Hydroxytryptamine 3-receptor antagonist modulates gallbladder emptying and motilin release induced by erythromycin  

Microsoft Academic Search

In the present study we evaluated the effect of ondansetron (formerly indicated as GR38032F), a potent and selective type-3 5-hydroxytryptamine receptor antagonist, on erythromycin-induced gallbladder emptying and motilin release, as well as gallbladder emptying induced by a regular meal in healthy volunteers. Gallbladder emptying was evaluated by sonography. Ondansetron, at the dose of 0.05 mg\\/kg, significantly reduced (PP<0.001, by ANOVA).

Stefano Fiorucci; Luca Santucci; Antonio Morelli

1993-01-01

222

Signal transduction through the fibronectin receptor induces collagenase and stromelysin gene expression  

Microsoft Academic Search

We have investigated the effects of ligation of the fibronectin receptor (FnR) on gene expression in rabbit synovial fibroblasts. Monoclonal antibodies to the FnR that block initial adhesion of fibroblasts to fibronectin induced the expression of genes encoding the secreted extracellular matrix-degrading metallo- proteinases collagenase and stromelysin. That induc- tion was a direct consequence of interaction with the FnR was

Zena Werb; Patrice M. Tremble; Ole Behrendtsen; Eileen Crowley; Caroline H. Damskytll

1989-01-01

223

Guanine nucleotide regulation of dopamine receptor agonist affinity states in rat estradiol-induced pituitary tumors  

SciTech Connect

The authors have investigated dopamine (DA) receptor agonist high- and low-affinity states in female rate estradiol-induced prolactin (PRL)-secreting pituitary tumors and intact pituitary tissue. Estradiol treatment increased the anterior pituitary weight 9-fold and plasma prolactin levels 74-fold and these measures are correlated (R = 0.745, n = 73, p < 0.001). Competition for (/sup 3/H)-spiperone binding to the DA receptor by apomorphine was compared in normal and adenomatous pituitary tissue. The inhibition constants (Ki) and the proportions of the two apomorphine sites are unchanged in tumors compared to intact pituitary tissue. Guanosine 5'-(..beta..-..gamma..-imino)triphosphate (Gpp(NH)p) causes complete conversion of the high into low affinity dopaminergic agonist site in normal pituitary and in tumors. These results suggest that rats with primary estradiol-induced pituitary tumors have normal and functional DA receptors. 9 references, 2 tables.

Di Paolo, T.; Falardeau, P.

1987-08-31

224

Liver X receptor ? activation induces pyroptosis of human and murine colon cancer cells.  

PubMed

Liver X receptors (LXRs) have been proposed to have some anticancer properties, through molecular mechanisms that remain elusive. Here we report for the first time that LXR ligands induce caspase-1-dependent cell death of colon cancer cells. Caspase-1 activation requires Nod-like-receptor pyrin domain containing 3 (NLRP3) inflammasome and ATP-mediated P2 × 7 receptor activation. Surprisingly, LXR? is mainly located in the cytoplasm and has a non-genomic role by interacting with pannexin 1 leading to ATP secretion. Finally, LXR ligands have an antitumoral effect in a mouse colon cancer model, dependent on the presence of LXR?, pannexin 1, NLRP3 and caspase-1 within the tumor cells. Our results demonstrate that LXR?, through pannexin 1 interaction, can specifically induce caspase-1-dependent colon cancer cell death by pyroptosis. PMID:25124554

Derangčre, V; Chevriaux, A; Courtaut, F; Bruchard, M; Berger, H; Chalmin, F; Causse, S Z; Limagne, E; Végran, F; Ladoire, S; Simon, B; Boireau, W; Hichami, A; Apetoh, L; Mignot, G; Ghiringhelli, F; Rébé, C

2014-12-01

225

Lipoprotein lipase binds to low density lipoprotein receptors and induces receptor-mediated catabolism of very low density lipoproteins in vitro.  

PubMed

Lipoprotein lipase (LPL), the major enzyme responsible for the hydrolysis of plasma triglycerides, promotes binding and catabolism of triglyceride-rich lipoproteins by various cultured cells. Recent studies demonstrate that LPL binds to three members of the low density lipoprotein (LDL) receptor family, including the LDL receptor-related protein (LRP), GP330/LRP-2, and very low density lipoprotein (VLDL) receptors and induces receptor-mediated lipoprotein catabolism. We show here that LDL receptors also bind LPL and mediate LPL-dependent catabolism of large VLDL with Sf 100-400. Up-regulation of LDL receptors by lovastatin treatment of normal human foreskin fibroblasts (FSF cells) resulted in an increase in LPL-induced VLDL binding and catabolism to a level that was 10-15-fold greater than in LDL receptor-negative fibroblasts, despite similar LRP activity in both cell lines. This indicates that the contribution of LRP to LPL-dependent degradation of VLDL is small when LDL receptors are maximally up-regulated. Furthermore studies in LRP-deficient murine embryonic fibroblasts showed that the level of LPL-dependent degradation of VLDL was similar to that in normal murine embryonic fibroblasts. LPL also promoted the internalization of protein-free triglyceride emulsions; lovastatin-treatment resulted in 2-fold higher uptake in FSF cells, indicating that LPL itself could bind to LDL receptors. However, the lower induction of emulsion catabolism as compared with native VLDL suggests that LPL-induced catabolism via LDL receptors is only partially dependent on receptor binding by LPL and instead is primarily due to activation of apolipoproteins such as apoE. A fusion protein between glutathione S-transferase and the catalytically inactive carboxyl-terminal domain of LPL (GST-LPLC) also induced binding and catabolism of VLDL. However GST-LPLC was not as active as native LPL, indicating that lipolysis is required for a maximal LPL effect. Mutations of critical tryptophan residues in GST-LPLC that abolished binding to VLDL converted the protein to an inhibitor of lipoprotein binding to LDL receptors. In solid-phase assays using immobilized receptors, LDL receptors bound to LPL in a dose-dependent manner. Both LPL and GST-LPLC promoted binding of VLDL to LDL receptor-coated wells. These results indicate that LPL binds to LDL receptors and suggest that the carboxyl-terminal domain of LPL contributes to this interaction. PMID:8663292

Medh, J D; Bowen, S L; Fry, G L; Ruben, S; Andracki, M; Inoue, I; Lalouel, J M; Strickland, D K; Chappell, D A

1996-07-19

226

Basis for defective responses of rheumatoid arthritis synovial fluid lymphocytes to anti-CD3 (T3) antibodies.  

PubMed Central

Synovial fluid mononuclear cells (SFMC) from patients with active rheumatoid arthritis characteristically respond poorly to mitogens. In this study, mitogenic antibodies reactive with the CD3(T3) antigen on human T lymphocytes were used to analyze the basis for the deficiency. OKT3-induced proliferation and release of interleukin 1 (IL-1) and interleukin 2 (IL-2) from SFMC were depressed in all patients. Purified IL-1 or recombinant IL-2 restored proliferative responses in SFMC and increased IL-2 receptor density. Exogenous IL-1 also enhanced IL-2 release. Fractionation of SFMC supernatants on phosphocellulose columns revealed the presence of IL-1 and a potent IL-1 inhibitor. The monocyte-derived IL-1 inhibitor blocked IL-1-dependent responses of normal peripheral blood lymphocytes to OKT3, but had no effect on IL-2-dependent events. These results suggest that IL-1 inhibitor(s) in SFMC impair(s) OKT3-induced mitogenesis by interfering with the effects of IL-1 on T lymphocytes. The net result is deficient IL-2 secretion, IL-2 receptor expression, and impaired cellular proliferation. This novel inhibitory circuit provides a rational explanation for the diminished function of synovial fluid T lymphocytes in rheumatoid arthritis patients. PMID:3091636

Lotz, M; Tsoukas, C D; Robinson, C A; Dinarello, C A; Carson, D A; Vaughan, J H

1986-01-01

227

Glucocorticoid Receptor Isoforms and in in Vitro Cytokine-induced Glucocorticoid Insensitivity  

Microsoft Academic Search

We stimulated peripheral blood mononuclear cells from 14 healthy subjects, 14 patients with stable asthma, and 13 patients with unsta- ble asthma with interleukin (IL)-2 and IL-4 to induce glucocorticoid insensitivity and we examined the relationship between insensitiv- ity and the expression of glucocorticoid receptor (GR) isoforms. Results are expressed as IC50 (nanomolar) values (means SD) in proliferation assays and

Alfons Torrego; Laura Pujols; Jordi Roca-Ferrer; Joaquim Mullol; Antoni Xaubet; Cesar Picado

228

Hypoglycemia induced changes in cholinergic receptor expression in the cerebellum of diabetic rats  

Microsoft Academic Search

Glucose homeostasis in humans is an important factor for the functioning of nervous system. Hypoglycemia and hyperglycemia is found to be associated with central and peripheral nerve system dysfunction. Changes in acetylcholine receptors have been implicated in the pathophysiology of many major diseases of the central nervous system (CNS). In the present study we showed the effects of insulin induced

Sherin Antony; Peeyush Kumar T; Jobin Mathew; TR Anju; CS Paulose

2010-01-01

229

Characteristics of the peroxisome proliferator activated receptor ? (PPAR?) ligand induced apoptosis in colon cancer cells  

Microsoft Academic Search

Background: Involvement of peroxisome proliferator activated receptor ? (PPAR?) in the growth response of colon cancer cells has been suggested.Aims: To investigate the characteristics of PPAR? induced apoptosis in colon cancer cells.Methods: The effects of ligands for each of the PPAR subtypes (?, ?, and ?) on DNA synthesis and cell viability were examined in HT-29 colon cancer cells. Modulation

T Shimada; K Kojima; K Yoshiura; H Hiraishi; A Terano

2002-01-01

230

RESEARCH Open Access Targeting early B-cell receptor signaling induces  

E-print Network

RESEARCH Open Access Targeting early B-cell receptor signaling induces apoptosis in leukemic mantle) signaling pathways are important for in vitro survival of mantle cell lymphoma (MCL) cells. To further identify early BCR-activated signaling pathways involved in MCL cell survival, we focused our study on BCR

Paris-Sud XI, Université de

231

Could hormone-induced loss of gonadotrophin receptors reduce the efficiency of superovulations stimulated by PMSG ?  

E-print Network

Could hormone-induced loss of gonadotrophin receptors reduce the efficiency of superovulations, 1976 ; Seidel et al., 1978). Pituitary follicle stimulating hormone (FSH) is unlikely to be ever, as well as FSH activity, it also acts as a luteinizing or interstitial cell stimulating hormone (Papkoff

Boyer, Edmond

232

Heparin-Binding Epidermal Growth Factor Cleavage Mediates Zinc-Induced Epidermal Growth Factor Receptor Phosphorylation  

Microsoft Academic Search

We have previously shown that exposure to zinc ions can acti- vate epidermal growth factor (EGF) receptor (EGFR) signaling in murine fibroblasts and A431 cells through a mechanism in- volving Src kinase. While studying the effects of zinc ions in normal human bronchial epithelial cell, we uncovered evidence for an additional mechanism of Zn 2 -induced EGFR activation. Exposure to

Weidong Wu; James M. Samet; Robert Silbajoris; Lisa A. Dailey; Dean Sheppard; Philip A. Bromberg; Lee M. Graves

2004-01-01

233

Peroxisome Proliferator-Activated Receptor-/ Protects Against Chemically Induced Liver Toxicity in Mice  

E-print Network

Peroxisome Proliferator-Activated Receptor- / Protects Against Chemically Induced Liver Toxicity M. Ward,5 Frank J. Gonzalez,4 and Jeffrey M. Peters1-3 Potential functional roles for the peroxisome bind- ing to peroxisome proliferator response elements, leading to increased expression of PPAR target

Omiecinski, Curtis

234

Peroxisome Proliferator-Activated Receptor Protects Against Alcohol-Induced Liver Damage  

E-print Network

Peroxisome Proliferator-Activated Receptor Protects Against Alcohol-Induced Liver Damage Tamie alcoholic liver disease are not completely understood, but lipid accumulation seems to be central. To investi- gate the roles of PPAR in alcoholic liver injury, wild-type and PPAR -null mice were continuously

Omiecinski, Curtis

235

Mdm2 and stress-inducing agents regulate1 estrogen receptor turn-over and transactivation.  

E-print Network

stress, acting both on gene transcription and protein stability by targeting the Mdm2 protein. 2Mdm2 and stress-inducing agents regulate1 2 3 4 5 6 7 8 9 10 11 12 13 14 estrogen receptor turn approaches, we showed that the Mdm2 oncogenic ubiquitin-ligase directly interacted with ER and is involved

Paris-Sud XI, Université de

236

Cholesterol Regulates ?-Opioid Receptor-Induced ?-Arrestin 2 Translocation to Membrane Lipid RaftsS?  

PubMed Central

?-Opioid receptor (OPRM1) is mainly localized in lipid raft microdomains but internalizes through clathrin-dependent pathways. Our previous studies demonstrated that disruption of lipid rafts by cholesterol-depletion reagent blocked the agonist-induced internalization of OPRM1 and G protein-dependent signaling. The present study demonstrated that reduction of cholesterol level decreased and culturing cells in excess cholesterol increased the agonist-induced internalization and desensitization of OPRM1, respectively. Further analyses indicated that modulation of cellular cholesterol level did not affect agonist-induced receptor phosphorylation but did affect membrane translocation of ?-arrestins. The translocation of ?-arrestins was blocked by cholesterol reduction, and the effect could be reversed by incubating with cholesterol. OptiPrep gradient separation of lipid rafts revealed that excess cholesterol retained more receptors in lipid raft domains and facilitated the recruitment of ?-arrestins to these microdomains upon agonist activation. Moreover, excess cholesterol could evoke receptor internalization and protein kinase C-independent extracellular signal-regulated kinases activation upon morphine treatment. Therefore, these results suggest that cholesterol not only can influence OPRM1 localization in lipid rafts but also can effectively enhance the recruitment of ?-arrestins and thereby affect the agonist-induced trafficking and agonist-dependent signaling of OPRM1. PMID:21518774

Qiu, Yu; Wang, Yan; Chen, Hong-Zhuan; Loh, Horace H.

2011-01-01

237

Lipopolysaccharide-induced modulation in the expression of progesterone receptor and estradiol receptor leads to early pregnancy loss in mouse.  

PubMed

The objective of the present study was to investigate the effect of Gram-negative bacteria infection on ovarian steroid receptors, i.e. progesterone receptor (PR) and estradiol receptor (ER) during preimplantation days of pregnancy. A well established mouse model of Gram-negative bacteria infection was used to test this objective. Mice were treated with normal saline or lipopolysaccharide (LPS) on day 0.5 of pregnancy and used to collect embryos and uterine horns on day 1.5 to day 4.42 preimplantation day of pregnancy. Total RNA was extracted and reverse-transcription polymerase chain reaction (PCR) was performed to check the expression of PR and ER genes. The mRNA expression of PR and ER was altered in embryos and uterus of LPS-treated animals during preimplantation days of pregnancy studied. These results suggest that PR and ER play an important role in Gram-negative bacteria infection and induced implantation failure in mouse. PMID:22809764

Agrawal, Varkha; Jaiswal, Mukesh Kumar; Jaiswal, Yogesh Kumar

2013-11-01

238

Serotonergic modulation in neuropathy induced by oxaliplatin: effect on the 5HT2C receptor.  

PubMed

Fluoxetine has been shown to be effective in clinical and experimental studies of neuropathic pain. Besides to increase serotonin levels in the synaptic cleft, fluoxetine is able to block the serotonergic 5-HT2C receptor subtype, which in turn has been involved in the modulation of neuropathic pain. This study investigated the effect of repeated treatments with fluoxetine on the neuropathic nociceptive response induced by oxaliplatin and the effects of both treatments on 5-HT2C receptor mRNA expression and protein levels in the rat spinal cord (SC), rostral ventral medulla (RVM), midbrain periaqueductal gray (PAG) and amygdala (Amy). Nociception was assessed by paw-pressure, cold plate and Von Frey tests. Fluoxetine prevented mechanical hypersensitivity and pain threshold alterations induced by oxaliplatin but did not prevent the impairment in weight gain induced by this anticancer drug. Ex vivo analysis revealed that oxaliplatin increased the 5-HT2C receptor mRNA expression and protein levels in the SC and PAG. Similar effects were observed in fluoxetine-treated animals but only within the PAG. While oxaliplatin decreased the 5-HT2C mRNA expression levels in the Amy, fluoxetine increased their protein levels in this area. Fluoxetine impaired the oxaliplatin effects on the 5-HT2C receptor mRNA expression in the SC and Amy and protein levels in the SC. All treatments increased of 5-HT2C receptor mRNA expression and protein levels in the PAG. These results suggest that the effects of fluoxetine on neuropathic pain induced by oxaliplatin are associated with quantitative changes in the 5-HT2C receptors located within important areas of the nociceptive system. PMID:24786153

Baptista-de-Souza, Daniela; Di Cesare Mannelli, Lorenzo; Zanardelli, Matteo; Micheli, Laura; Nunes-de-Souza, Ricardo Luiz; Canto-de-Souza, Azair; Ghelardini, Carla

2014-07-15

239

Peroxisome proliferator-activated receptor {alpha} agonist-induced down-regulation of hepatic glucocorticoid receptor expression in SD rats  

SciTech Connect

It was reported that glucocorticoid production was inhibited by fenofibrate through suppression of type-1 11{beta}-hydroxysteroid dehydrogenase gene expression in liver. The inhibition might be a negative-feedback regulation of glucocorticoid receptor (GR) activity by peroxisome proliferator-activated receptor alpha (PPAR{alpha}), which is quickly induced by glucocorticoid in the liver. However, it is not clear if GR expression is changed by fenofibrate-induced PPAR{alpha} activation. In this study, we tested this possibility in the liver of Sprague-Dawley rats. GR expression was reduced by fenofibrate in a time- and does-dependent manner. The inhibition was observed in liver, but not in fat and muscle. The corticosterone level in the blood was increased significantly by fenofibrate. These effects of fenofibrate were abolished by PPAR{alpha} inhibitor MK886, suggesting that fenofibrate activated through PPAR{alpha}. In conclusion, inhibition of GR expression may represent a new molecular mechanism for the negative feedback regulation of GR activity by PPAR{alpha}.

Chen Xiang; Li Ming; Sun Weiping; Bi Yan; Cai Mengyin; Liang Hua; Yu Qiuqiong; He Xiaoying [Department of Endocrinology, Third Affiliated Hospital of Sun Yat-Sen University, 600 Tianhe Road, Guangzhou, Guang Dong 510630 (China); Weng Jianping [Department of Endocrinology, Third Affiliated Hospital of Sun Yat-Sen University, 600 Tianhe Road, Guangzhou, Guang Dong 510630 (China)], E-mail: wjianp@mail.sysu.edu.cn

2008-04-18

240

Estradiol-induced desensitization of 5-HT1A receptor signaling in the paraventricular nucleus of the hypothalamus is independent of estrogen receptor-beta  

PubMed Central

Summary Estradiol regulates serotonin 1A(5-HT1A) receptor signaling. Since desensitization of 5-HT1A receptors may be an underlying mechanism by which selective serotonin reuptake inhibitors (SSRIs) mediate their therapeutic effects and combining estradiol with SSRIs enhances the efficacy of the SSRIs, it is important to determine which estrogen receptors are capable of desensitizating 5-HT1A receptor function. We previously demonstrated that selective activation of the estrogen receptor, GPR30, desensitizes 5-HT1A receptor signaling in rat hypothalamic paraventricular nucleus(PVN). However, since estrogen receptor beta(ER?), is highly expressed in the PVN, we investigated the role of ER? in estradiol-induced desensitization of 5-HT1A receptor signaling. We first showed that a selective ER? agonist, diarylpropionitrile(DPN) has a 100-fold lower binding affinity than estradiol for GPR30. Administration of DPN did not desensitize 5-HT1A receptor signaling in rat PVN as demonstrated by agonist-stimulated hormone release. Second, we used a recombinant adenovirus containing ER? siRNAs to decrease ER? expression in the PVN. Reductions in ER? did not alter the estradiol-induced desensitization of 5-HT1A receptor signaling in oxytocin cells. In contrast, in animals with reduced ER?, estradiol administration, instead of producing desensitization, augmented the ACTH response to a 5-HT1A agonist. Combined with the results from the DPN treatment experiments, desensitization of 5-HT1A receptor signaling does not appear to be mediated by ER? in oxytocin cells, but that ER?, together with GPR30, may play a complex role in central regulation of 5-HT1A-mediated ACTH release. Determining the mechanisms by which estrogens induce desensitization may aid in the development of better treatments for mood disorders. PMID:20138435

Rossi, Dania V.; Dai, Ying; Thomas, Peter; Carrasco, Gonzalo A.; DonCarlos, Lydia L.; Muma, Nancy A.; Li, Qian

2010-01-01

241

Histamine 4 receptor plays an important role in auto-antibody-induced arthritis.  

PubMed

Rheumatoid arthritis is a widespread autoimmune disease. In the murine K/B×N arthritis model, anti-GPI (anti-glucose 6-phosphate isomerase) antibodies lead to the formation of immune complexes. In the course of pathogenesis, these complexes activate the immune system and induce degranulation of mast cells, which are essential in this model of rheumatoid arthritis. A major mediator in mast cell granules is histamine, which is proven to be indispensable for joint inflammation in K/B×N mice. Histamine is known to bind to four different receptors (HR1-4), which have different expression profiles and exert a variety of different functions, including activation of the immune system. To analyze the contribution of the different histamine receptors, we employed histamine receptor antagonists (cetirizine, ranitidine, thioperamide and clozapine) blocking the receptors in C57BL/6 mice. Arthritis was induced via K/B×N serum injection. The results demonstrated that mice treated with all four histamine receptor antagonists simultaneously showed no arthritic symptoms, while positive control mice injected with K/B×N serum and vehicle suffered from severe symptoms. When antagonists specific for HR1-4 were applied individually, only the HR4 antagonist clozapine could protect mice from arthritis, reflecting its expression and functionality in the immune system. PMID:23545338

Nent, Elisa; Frommholz, David; Gajda, Mieczyslaw; Bräuer, Rolf; Illges, Harald

2013-07-01

242

Role of direct estrogen receptor signaling in wear particle-induced osteolysis  

PubMed Central

Estrogen withdrawal following surgical ovariectomy was recently shown to mitigate particle-induced osteolysis in the murine calvarial model. Currently, we hypothesize that estrogen receptors (ERs) were involved in this paradoxical phenomenon. To test this hypothesis, we first evaluated polyethylene (PE) particle-induced osteolysis in the murine calvarial model, using wild type (WT) C57BL6J female mice, ER? deficient (ER?KO) mice, and WT mice either treated with 17?-estradiol (E2) or with the ER pan-antagonist ICI 182,780. According to micro-CT and histomorphometry, we showed that bone resorption was consistently altered in both ER?KO and ICI 182,780 treated mice as compared to WT and E2 groups. Then, we demonstrated that ER disruption consistently decreased both PE and polymethylmethacrylate (PMMA) particle-induced production of TNF-? by murine macrophages in vitro. Similar results were obtained following ER blockade using ICI 182,780 in RAW 264.7 and WT macrophages. ER disruption and pre treatment with ICI 182,780 resulted in a consistent down-regulation of particle-induced TNF-? mRNA expression relative to WT macrophages or untreated RAW cells. These results indicate that the response to wear particles involves estrogen receptors in female mice, as part of macrophage activation. Estrogen receptors may be considered as a future therapeutic target for particle-induced osteolysis. PMID:23113918

Nich, Christophe; Rao, Allison J.; Valladares, Roberto D.; Li, Chenguang; Christman, Jane E.; Antonios, Joseph K.; Yao, Zhenyu; Zwingenberger, Stefan; Petite, Hervé; Hamadouche, Moussa; Goodman, Stuart B.

2014-01-01

243

Sensitization of cutaneous neuronal purinergic receptors contributes to endothelin-1-induced mechanical hypersensitivity.  

PubMed

Endothelin (ET-1), an endogenous peptide with a prominent role in cutaneous pain, causes mechanical hypersensitivity in the rat hind paw, partly through mechanisms involving local release of algogenic molecules in the skin. The present study investigated involvement of cutaneous ATP, which contributes to pain in numerous animal models. Pre-exposure of ND7/104 immortalized sensory neurons to ET-1 (30nM) for 10min increased the proportion of cells responding to ATP (2?M) with an increase in intracellular calcium, an effect prevented by the ETA receptor-selective antagonist BQ-123. ET-1 (3nM) pre-exposure also increased the proportion of isolated mouse dorsal root ganglion neurons responding to ATP (0.2-0.4?M). Blocking ET-1-evoked increases in intracellular calcium with the IP3 receptor antagonist 2-APB did not inhibit sensitization to ATP, indicating a mechanism independent of ET-1-mediated intracellular calcium increases. ET-1-sensitized ATP calcium responses were largely abolished in the absence of extracellular calcium, implicating ionotropic P2X receptors. Experiments using quantitative polymerase chain reaction and receptor-selective ligands in ND7/104 showed that ET-1-induced sensitization most likely involves the P2X4 receptor subtype. ET-1-sensitized calcium responses to ATP were strongly inhibited by broad-spectrum (TNP-ATP) and P2X4-selective (5-BDBD) antagonists, but not antagonists for other P2X subtypes. TNP-ATP and 5-BDBD also significantly inhibited ET-1-induced mechanical sensitization in the rat hind paw, supporting a role for purinergic receptor sensitization in vivo. These data provide evidence that mechanical hypersensitivity caused by cutaneous ET-1 involves an increase in the neuronal sensitivity to ATP in the skin, possibly due to sensitization of P2X4 receptors. PMID:24569146

Barr, Travis P; Hrnjic, Alen; Khodorova, Alla; Sprague, Jared M; Strichartz, Gary R

2014-06-01

244

Interleukin-1? mediates virus-induced m2 muscarinic receptor dysfunction and airway hyperreactivity.  

PubMed

Respiratory viral infections are associated with the majority of asthma attacks. Inhibitory M2 receptors on parasympathetic nerves, which normally limit acetylcholine (ACh) release, are dysfunctional after respiratory viral infection. Because IL-1? is up-regulated during respiratory viral infections, we investigated whether IL-1? mediates M2 receptor dysfunction during parainfluenza virus infection. Virus-infected guinea pigs were pretreated with the IL-1? antagonist anakinra. In the absence of anakinra, viral infection increased bronchoconstriction in response to vagal stimulation but not to intravenous ACh, and neuronal M2 muscarinic receptors were dysfunctional. Pretreatment with anakinra prevented virus-induced increased bronchoconstriction and M2 receptor dysfunction. Anakinra did not change smooth muscle M3 muscarinic receptor response to ACh, lung viral loads, or blood and bronchoalveolar lavage leukocyte populations. Respiratory virus infection decreased M2 receptor mRNA expression in parasympathetic ganglia extracted from infected animals, and this was prevented by blocking IL-1? or TNF-?. Treatment of SK-N-SH neuroblastoma cells or primary cultures of guinea pig parasympathetic neurons with IL-1? directly decreased M2 receptor mRNA, and this was not synergistic with TNF-? treatment. Treating guinea pig trachea segment with TNF-? or IL-1? in vitro increased tracheal contractions in response to activation of airway nerves by electrical field stimulation. Blocking IL-1? during TNF-? treatment prevented this hyperresponsiveness. These data show that virus-induced hyperreactivity and M2 dysfunction involves IL-1? and TNF-?, likely in sequence with TNF-? causing production of IL-1?. PMID:24735073

Rynko, Abby E; Fryer, Allison D; Jacoby, David B

2014-10-01

245

Attenuation of obesity-induced adipose tissue inflammation in C3H/HeJ mice carrying a Toll-like receptor 4 mutation.  

PubMed

Obese adipose tissue is characterized by increased infiltration of macrophages, suggesting that they might represent an important source of inflammation. We have provided in vitro evidence that saturated fatty acids, which are released from hypertrophied adipocytes via the macrophage-induced adipocyte lipolysis, serve as a naturally occurring ligand for Toll-like receptor 4 (TLR4) to induce the inflammatory changes in macrophages. Here we show the attenuation of adipose tissue inflammation in C3H/HeJ mice carrying a functional mutation in the TLR4 gene relative to control C3H/HeN mice during a 16-week high-fat diet. We also find that adiponectin mRNA expression is significantly reduced by co-culture of hypertrophied 3T3-L1 adipocytes and C3H/HeN peritoneal macrophages, which is reversed, when co-cultured with C3H/HeJ peritoneal macrophages. This study provides in vivo evidence that TLR4 plays a role in obesity-related adipose tissue inflammation and thus helps to identify the therapeutic targets that may reduce obesity-induced inflammation and the metabolic syndrome. PMID:17210129

Suganami, Takayoshi; Mieda, Tae; Itoh, Michiko; Shimoda, Yuri; Kamei, Yasutomi; Ogawa, Yoshihiro

2007-03-01

246

ABCD2 Alters Peroxisome Proliferator-Activated Receptor ? Signaling In Vitro, but Does Not Impair Responses to Fenofibrate Therapy in a Mouse Model of Diet-Induced Obesity.  

PubMed

Fenofibrate is a peroxisome proliferator-activated receptor (PPAR) ? ligand that has been widely used as a lipid-lowering agent in the treatment of hypertriglyceridemia. ABCD2 (D2) is a peroxisomal long-chain acyl-CoA transporter that is highly induced by fenofibrate in the livers of mice. To determine whether D2 is a modifier of fibrate responses, wild-type and D2-deficient mice were treated with fenofibrate for 14 days. The absence of D2 altered expression of gene clusters associated with lipid metabolism, including PPAR? signaling. Using 3T3-L1 adipocytes, which express high levels of D2, we confirmed that knockdown of D2 modified genomic responses to fibrate treatment. We next evaluated the impact of D2 on effects of fibrates in a mouse model of diet-induced obesity. Fenofibrate treatment opposed the development of obesity, hypertriglyceridemia, and insulin resistance. However, these effects were unaffected by D2 genotype. We concluded that D2 can modulate genomic responses to fibrates, but that these effects are not sufficiently robust to alter the effects of fibrates on diet-induced obesity phenotypes. PMID:25123288

Liu, Xiaoxi; Liu, Jingjing; Liang, Shuang; Schlüter, Agatha; Fourcade, Stephane; Aslibekyan, Stella; Pujol, Aurora; Graf, Gregory A

2014-11-01

247

Mitigative Effect of Erythromycin on PMMA Challenged Preosteoblastic MC3T3-E1 Cells  

PubMed Central

Background. Aseptic loosening (AL) is a major complication of total joint replacement. Recent approaches to limiting AL have focused on inhibiting periprosthetic inflammation and osteoclastogenesis. Questions/Purposes. The purpose of this study was to determine the effects of erythromycin (EM) on polymethylmethacrylate (PMMA) particle-challenged MC3T3 osteoblast precursor cells. Methods. MC3T3 cells were pretreated with EM (0–10??g/mL) and then stimulated with PMMA (1?mg/mL). Cell viability was evaluated by both a lactate dehydrogenase (LDH) release assay and cell counts. Cell differentiation was determined by activity of alkaline phosphatase (ALP). Gene expression was measured via real-time quantitative RT-PCR. Results. We found that exposure to PMMA particles reduced cellular viability and osteogenetic potential in MC3T3 cell line. EM treatment mitigated the effects of PMMA particles on the proliferation, viability and differentiation of MC3T3 cells. PMMA decreased the gene expression of Runx2, osterix and osteocalcin, which can be partially restored by EM treatment. Furthermore, EM suppressed PMMA- induced increase of NF-?B gene expression. Conclusions. These data demonstrate that EM mitigates the effects of PMMA on MC3T3 cell viability and differentiation, in part through downregulation of NF-?B pathway. EM appeared to represent an anabolic agent on MC3T3 cells challenged with PMMA particles. PMID:25110723

Shen, Yi; Wang, Weili; Li, Xiaomiao; Markel, David C.; Ren, Weiping

2014-01-01

248

Structural insights into ligand-induced activation of the insulin receptor  

SciTech Connect

The current model for insulin binding to the insulin receptor proposes that there are two binding sites, referred to as sites 1 and 2, on each monomer in the receptor homodimer and two binding surfaces on insulin, one involving residues predominantly from the dimerization face of insulin (the classical binding surface) and the other residues from the hexamerization face. High-affinity binding involves one insulin molecule using its two surfaces to make bridging contacts with site 1 from one receptor monomer and site 2 from the other. Whilst the receptor dimer has two identical site 1-site 2 pairs, insulin molecules cannot bridge both pairs simultaneously. Our structures of the insulin receptor (IR) ectodomain dimer and the L1-CR-L2 fragments of IR and insulin-like growth factor receptor (IGF-1R) explain many of the features of ligand-receptor binding and allow the two binding sites on the receptor to be described. The IR dimer has an unexpected folded-over conformation which places the C-terminal surface of the first fibronectin-III domain in close juxtaposition to the known L1 domain ligand-binding surface suggesting that the C-terminal surface of FnIII-1 is the second binding site involved in high-affinity binding. This is very different from previous models based on three-dimensional reconstruction from scanning transmission electron micrographs. Our single-molecule images indicate that IGF-1R has a morphology similar to that of IR. In addition, the structures of the first three domains (L1-CR-L2) of the IR and IGF-1R show that there are major differences in the two regions governing ligand specificity. The implications of these findings for ligand-induced receptor activation will be discussed. This review summarizes the key findings regarding the discovery and characterization of the insulin receptor, the identification and arrangement of its structural domains in the sequence and the key features associated with ligand binding. The remainder of the review deals with a description of the receptor structure and how it explains much of the large body of biochemical data in the literature on insulin binding and receptor activation.

Ward, C.; Lawrence, M.; Streltsov, V.; Garrett, T.; McKern, N.; Lou, M.-Z.; Lovrecz, G.; Adams, T. (CSIRO); (WEHIMR)

2008-04-29

249

Role of periaqueductal grey prostaglandin receptors in formalin-induced hyperalgesia.  

PubMed

In this study we have investigated the role of periaqueductal grey prostaglandin receptors in formalin-induced hyperalgesia in mice. Glutamate and GABA release changes have been monitored by in vivo microdialysis. Intra-periaqueductal grey microinjections of misoprostol, a non-selective prostaglandin receptor agonist, increased nociceptive responses in the formalin test only during the late phase. Prostanoid EP(1) (L-335677), EP(2) (AH 6809), EP(3) (L-826266) and EP(4) (L-161982) receptor antagonists prevented the nociceptive response induced by misoprostol in formalin-injected mice. Prostanoid EP(1), EP(2), EP(3) and EP(4) antagonists reduced, per se, the late hyperalgesic phase. Intra-periaqueductal grey perfusion with misoprostol increased periaqueductal grey glutamate, whereas it produced an increase followed by a decrease in GABA. Likewise, formalin increased glutamate and produced a biphasic response on GABA. When misoprostol was perfused in combination with the peripheral injection of formalin, we observed an increase of glutamate and an increase followed by a stronger decrease in GABA release. These data show that periaqueductal grey prostaglandin receptor stimulation increased formalin-induced nociceptive response in the late phase by increasing glutamate release and by producing a biphasic change in GABA release. PMID:16360148

Oliva, Patrizia; Berrino, Liberato; de Novellis, Vito; Palazzo, Enza; Marabese, Ida; Siniscalco, Dario; Scafuro, Mariantonietta; Mariani, Loredana; Rossi, Francesco; Maione, Sabatino

2006-01-13

250

Activation of Protease-Activated Receptor 2 Induces VEGF Independently of HIF-1  

PubMed Central

Background Human adipose stem cells (hASCs) can promote angiogenesis through secretion of proangiogenic factors such as vascular endothelial growth factor (VEGF). In other cell types, it has been shown that induction of VEGF is mediated by both protease activated receptor 2 (PAR2) and hypoxia inducible factor 1(HIF-1). The present study hypothesized that PAR2 stimulation through activation of kinase signaling cascades lead to induction of HIF-1 and secretion of VEGF. Methodology/Principal Findings Immunohistochemistry revealed the expression of PAR2 receptors on the surface of hASCs. Blocking the PAR2 receptors with a specific antibody prior to trypsin treatment showed these receptors are involved in trypsin-evoked increase in VEGF secretion from hASCs. Blocking with specific kinase inhibitors suggested that that activation of MEK/ERK and PI3-kinase/Akt pathways are involved in trypsin-eveoked induction of VEGF. The effect of the trypsin treatment on the transcription of VEGF peaked at 6 hours after the treatment and was comparable to the activation observed after keeping hASCs for 24 hours at 1% oxygen. In contrast to hypoxia, trypsin alone failed to induce HIF-1 measured with ELISA, while the combination of trypsin and hypoxia had an additive effect on both VEGF transcription and secretion, results which were confirmed by Western blot. Conclusion In hASCs trypsin and hypoxia induce VEGF expression through separate pathways. PMID:23049945

Rasmussen, Jeppe Gr?ndahl; Riis, Simone Elkjaer; Fr?bert, Ole; Yang, Sufang; Kastrup, Jens; Zachar, Vladimir; Simonsen, Ulf; Fink, Trine

2012-01-01

251

Role of spinal GABAA receptor reduction induced by stress in rat thermal hyperalgesia.  

PubMed

The mechanisms underlying stress-induced hyperalgesia (SIH) remain poorly understood. Recent findings have provided strong evidence indicating that SIH could be related, at least in part, to alterations in spinal cord GABA activity. In the present study, we first investigated how acute restraint stress impacted pain responses as assessed using the tail flick immersion test. These results showed that rats developed hyperalgesia at 6 h after being subjected to 1-h acute restraint stress. Second, we measured the activation of spinal neurons and alterations in expression of GABAA receptor ?2 and ?3 subunits as related to stress-induced hyperalgesia. Results from Western blot and immunofluorescence assays showed that c-fos protein increased in the dorsal horn of the lumbar spinal cord and GABAA receptor ?2 and ?3 subunit proteins decreased significantly at 6 h after exposure to 1 h of acute restraint stress. Finally, the effects of spinal GABAA receptor alteration on SIH were evaluated. These results showed that intrathecal administration of muscimol inhibited hyperalgesia induced by stress while bicuculline enhanced hyperalgesia in the control groups. Taken together, the present data reveal that GABAA receptor ?2 and ?3 decrease following 1 h of acute restraint stress and may play a critical role in SIH. PMID:24992900

Ma, Xuelian; Bao, Weiying; Wang, Xiujun; Wang, Zhilong; Liu, Qiaoran; Yao, Zhenyu; Zhang, Di; Jiang, Hong; Cui, Shuang

2014-11-01

252

Effect of dopamine and serotonin receptor antagonists on fencamfamine-induced abolition of latent inhibition.  

PubMed

The purpose of this investigation was to verify the role of dopamine and serotonin receptors in the effect of fencamfamine (FCF) on latent inhibition. FCF is a psychomotor stimulant with an indirect dopaminergic action. Latent inhibition is a model of attention. Latent inhibition is blocked by dopaminergic agents and facilitated by dopamine receptor agonists. FCF has been shown to abolish latent inhibition. The serotonergic system may also participate in the neurochemical mediation of latent inhibition. The selective dopamine D(1) receptor antagonist SCH 23390 (7-chloro-3-methyl-1-phenyl-1,2,4,5-tetrahydro-3-benzazepin-8-ol), D(2) receptor antagonists pimozide (PIM) and methoclopramide (METH), and serotonin 5-HT(2A/C) receptor antagonist ritanserin (RIT) were used in the present study. Latent inhibition was evaluated using a conditioned emotional response procedure. Male Wistar rats that were water-restricted were subjected to a three-phase procedure: preexposure to a tone, tone-shock conditioning, and a test of the effect of the tone on licking frequency. All of the drugs were administered before the preexposure and conditioning phases. The results showed that FCF abolished latent inhibition, and this effect was clearly antagonized by PIM and METH and moderately attenuated by SCH 23390. At the doses used in the present study, RIT pretreatment did not affect latent inhibition and did not eliminate the effect of FCF, suggesting that the FCF-induced abolition of latent inhibition is not mediated by serotonin 5-HT(2A/C) receptors. These results suggest that the effect of FCF on latent inhibition is predominantly related to dopamine D(2) receptors and that dopamine D(2) receptors participate in attention processes. PMID:23123352

de Aguiar, Cilene Rejane Ramos Alves; de Aguiar, Marlison José Lima; DeLucia, Roberto; Silva, Maria Teresa Araujo

2013-01-01

253

Neurosteroid Agonist at GABAA receptor induces persistent neuroplasticity in VTA dopamine neurons.  

PubMed

The main fast-acting inhibitory receptors in the mammalian brain are ?-aminobutyric acid type-A (GABAA) receptors for which neurosteroids, a subclass of steroids synthesized de novo in the brain, constitute a group of endogenous ligands with the most potent positive modulatory actions known. Neurosteroids can act on all subtypes of GABAA receptors, with a preference for ?-subunit-containing receptors that mediate extrasynaptic tonic inhibition. Pathological conditions characterized by emotional and motivational disturbances are often associated with perturbation in the levels of endogenous neurosteroids. We studied the effects of ganaxolone (GAN)-a synthetic analog of endogenous allopregnanolone that lacks activity on nuclear steroid receptors-on the mesolimbic dopamine (DA) system involved in emotions and motivation. A single dose of GAN in young mice induced a dose-dependent, long-lasting neuroplasticity of glutamate synapses of DA neurons ex vivo in the ventral tegmental area (VTA). Increased ?-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA)/N-methyl-D-aspartate ratio and rectification of AMPA receptor responses even at 6 days after GAN administration suggested persistent synaptic targeting of GluA2-lacking AMPA receptors. This glutamate neuroplasticity was not observed in GABAA receptor ?-subunit-knockout (?-KO) mice. GAN (500?nM) applied locally to VTA selectively increased tonic inhibition of GABA interneurons and triggered potentiation of DA neurons within 4?h in vitro. Place-conditioning experiments in adult wild-type C57BL/6J and ?-KO mice revealed aversive properties of repeated GAN administration that were dependent on the ?-subunits. Prolonged neuroadaptation to neurosteroids in the VTA might contribute to both the physiology and pathophysiology underlying processes and changes in motivation, mood, cognition, and drug addiction. PMID:24077066

Vashchinkina, Elena; Manner, Aino K; Vekovischeva, Olga; den Hollander, Bjřrnar; Uusi-Oukari, Mikko; Aitta-Aho, Teemu; Korpi, Esa R

2014-02-01

254

Cannabinoid CB1 receptor mediates glucocorticoid effects on hormone secretion induced by volume and osmotic changes.  

PubMed

The present study provides the first in vivo evidence that the cannabinoid CB(1) receptor mediates the effects of dexamethasone on hormone release induced by changes in circulating volume and osmolality. Male adult rats were administered with the CB(1) receptor antagonist rimonabant (10 mg/Kg, p.o.), followed or not in 1 hour by dexamethasone (1 mg/Kg, i.p.). Extracellular volume expansion (EVE, 2 mL/100 g of body weight, i.v.) was performed 2 hours after dexamethasone or vehicle treatment using either isotonic (I-EVE, 0.15 mol/L) or hypertonic (H-EVE, 0.30 mol/L) NaCl solution. Five minutes after EVE, animals were decapitated and trunk blood was collected for all plasma measurements. Rimonabant potentiated oxytocin (OT) secretion induced by H-EVE and completely reversed the inhibitory effects of dexamethasone in response to the same stimulus. These data suggest that glucocorticoid modulation of OT release is mediated by the CB(1) receptor. Although dexamethasone did not affect vasopressin (AVP) secretion induced by H-EVE, the administration of rimonabant potentiated AVP release in response to the same stimulus, supporting the hypothesis that the CB(1) receptor regulates AVP secretion independently of glucocorticoid-mediated signalling. Dexamethasone alone did not affect atrial natriuretic peptide (ANP) release stimulated by I-EVE or H-EVE. However, pretreatment with rimonabant potentiated ANP secretion induced by H-EVE, suggesting a possible role for the CB(1) receptor in the control of peripheral factors that modulate cardiovascular function. Rimonabant also reversed the inhibitory effects of dexamethasone on H-EVE-induced corticosterone secretion, reinforcing the hypothesis that the CB(1) receptor may be involved in the negative feedback exerted by glucocorticoids on the activity of the hypothalamic-pituitary-adrenal axis. Collectively, the results of the present study indicate that the CB(1) receptor modulates neurohypophyseal hormone secretion and systemic factors, such as corticosterone and ANP, thus participating in homeostatic responses to altered extracellular volume and plasma tonicity. PMID:22211674

Ruginsk, S G; Uchoa, E T; Elias, L L K; Antunes-Rodrigues, J

2012-02-01

255

Isolation of a cDNA clone encoding a biologically active thyroid hormone receptor.  

PubMed Central

We have isolated a c-erbA cDNA clone from a GH3 cell library. The clone, denoted erb62, is 4.5 kilobases long and encodes a 461-amino acid beta-type c-erbA protein. This c-erbA protein binds 3,5,3'-triiodothyronine (T3) and T3 analogs with affinities similar to those of the authentic T3 receptor. By RNA gel blot analysis, erb62 hybridizes to a 6-kilobase RNA found in organs that express T3 receptors--e.g., heart, kidney, and brain. A COS-cell transient cotransfection system was used to show that erb62 encodes a biologically active T3 receptor. An oligonucleotide, corresponding to a portion of the rat growth hormone gene 5'-flanking region that contains a T3 response element, was inserted on the 5' side of the herpes simplex virus thymidine kinase promoter in a chloramphenicol acetyltransferase-expressing plasmid. Reporter gene expression directed by this hybrid promoter was T3 inducible only if this plasmid was cotransfected with an erb62-expressing plasmid. Images PMID:2899322

Koenig, R J; Warne, R L; Brent, G A; Harney, J W; Larsen, P R; Moore, D D

1988-01-01

256

The aryl hydrocarbon receptor mediates raloxifene-induced apoptosis in estrogen receptor-negative hepatoma and breast cancer cells  

PubMed Central

Identification of new molecular targets for the treatment of breast cancer is an important clinical goal, especially for triple-negative breast cancer, which is refractory to existing targeted treatments. The aryl hydrocarbon receptor (AhR) is a ligand-activated transcription factor known primarily as the mediator of dioxin toxicity. However, the AhR can also inhibit cellular proliferation in a ligand-dependent manner and act as a tumor suppressor in mice, and thus may be a potential anticancer target. To investigate the AhR as an anticancer target, we conducted a small molecule screen to discover novel AhR ligands with anticancer properties. We identified raloxifene, a selective estrogen receptor (ER) modulator currently used in the clinic for prevention of ER-positive breast cancer and osteoporosis in post-menopausal women, as an AhR activator. Raloxifene directly bound the AhR and induced apoptosis in ER-negative mouse and human hepatoma cells in an AhR-dependent manner, indicating that the AhR is a molecular target of raloxifene and mediates raloxifene-induced apoptosis in the absence of ER. Raloxifene selectively induced apoptosis of triple-negative MDA-MB-231 breast cancer cells compared with non-transformed mammary epithelial cells via the AhR. Combined with recent data showing that raloxifene inhibits triple-negative breast cancer xenografts in vivo (Int J Oncol. 43(3):785-92, 2013), our results support the possibility of repurposing of raloxifene as an AhR-targeted therapeutic for triple-negative breast cancer patients. To this end, we also evaluated the role of AhR expression on survival of patients diagnosed with breast cancer. We found that higher expression of the AhR is significantly associated with increased overall survival and distant metastasis-free survival in both hormone-dependent (ER-positive) and hormone-independent (ER and progesterone receptor (PR)-negative) breast cancers. Together, our data strongly support the possibility of using the AhR as a molecular target for the treatment of hormone-independent breast cancers. PMID:24481452

O'Donnell, E F; Koch, D C; Bisson, W H; Jang, H S; Kolluri, S K

2014-01-01

257

Purinergic P2X7 Receptors Mediate ATP-induced Saliva Secretion by the Mouse Submandibular Gland*  

PubMed Central

Salivary glands express multiple isoforms of P2X and P2Y nucleotide receptors, but their in vivo physiological roles are unclear. P2 receptor agonists induced salivation in an ex vivo submandibular gland preparation. The nucleotide selectivity sequence of the secretion response was BzATP ? ATP > ADP ? UTP, and removal of external Ca2+ dramatically suppressed the initial ATP-induced fluid secretion (?85%). Together, these results suggested that P2X receptors are the major purinergic receptor subfamily involved in the fluid secretion process. Mice with targeted disruption of the P2X7 gene were used to evaluate the role of the P2X7 receptor in nucleotide-evoked fluid secretion. P2X7 receptor protein and BzATP-activated inward cation currents were absent, and importantly, purinergic receptor agonist-stimulated salivation was suppressed by more than 70% in submandibular glands from P2X7-null mice. Consistent with these observations, the ATP-induced increases in [Ca2+]i were nearly abolished in P2X7–/– submandibular acinar and duct cells. ATP appeared to also act through the P2X7 receptor to inhibit muscarinic-induced fluid secretion. These results demonstrate that the ATP-sensitive P2X7 receptor regulates fluid secretion in the mouse submandibular gland. PMID:19097994

Nakamoto, Tetsuji; Brown, David A.; Catalan, Marcelo A.; Gonzalez-Begne, Mireya; Romanenko, Victor G.; Melvin, James E.

2009-01-01

258

Painful Pathways Induced by Toll-like Receptor Stimulation of Dorsal Root Ganglion Neurons  

PubMed Central

We hypothesize that innate immune signals from infectious organisms and/or injured tissues may activate peripheral neuronal pain signals. In this study, we demonstrated that toll-like receptors 3/7/9 (TLRs) are expressed by human dorsal root ganglion neurons (DRGNs) and in cultures of primary mouse DRGNs. Stimulation of murine DRGNs with TLR ligands induced expression and production of proinflammatory chemokines and cytokines CCL5 (RANTES), CXCL10 (IP10), interleukin-1alpha, interleukin-1beta, and prostaglandin E2 (PGE2), which have previously been shown to augment pain. Further, TLR ligands up-regulated the expression of a nociceptive receptor transient receptor potential vanilloid type 1 (TRPV1), and enhanced calcium flux by TRPV1 expressing DRGNs. Using a tumor-induced temperature sensitivity model, we showed that in vivo administration of a TLR9 antagonist, known as a suppressive ODN, blocked tumor-induced temperature sensitivity. Taken together, these data indicate that stimulation of peripheral neurons by TLR ligands can induce nerve pain. PMID:21515789

Qi, Jia; Buzas, Krisztina; Fan, Huiting; Cohen, Jeffrey I.; Wang, Kening; Mont, Erik; Klinman, Dennis; Oppenheim, Joost J.; Howard, O.M. Zack

2011-01-01

259

Blockade of N-methyl-D-aspartate receptor activation suppresses learning-induced synaptic elimination.  

PubMed

Auditory filial imprinting in the domestic chicken is accompanied by a dramatic loss of spine synapses in two higher associative forebrain areas, the mediorostral neostriatum/hyperstriatum ventrale (MNH) and the dorsocaudal neostriatum (Ndc). The cellular mechanisms that underlie this learning-induced synaptic reorganization are unclear. We found that local pharmacological blockade of N-methyl-D-aspartate (NMDA) receptors in the MNH, a manipulation that has been shown previously to impair auditory imprinting, suppresses the learning-induced spine reduction in this region. Chicks treated with the NMDA receptor antagonist 2-amino-5-phosphonovaleric acid (APV) during the behavioral training for imprinting (postnatal day 0-2) displayed similar spine frequencies at postnatal day 7 as naive control animals, which, in both groups, were significantly higher than in imprinted animals. Because the average dendritic length did not differ between the experimental groups, the reduced spine frequency can be interpreted as a reduction of the total number of spine synapses per neuron. In the Ndc, which is reciprocally connected with the MNH and not directly influenced by the injected drug, learning-induced spine elimination was partly suppressed. Spine frequencies of the APV-treated, behaviorally trained but nonimprinted animals were higher than in the imprinted animals but lower than in the naive animals. These results provide evidence that NMDA receptor activation is required for the learning-induced selective reduction of spine synapses, which may serve as a mechanism of information storage specific for juvenile emotional learning events. PMID:10051669

Bock, J; Braun, K

1999-03-01

260

Carbachol inhibits TNF-?-induced endothelial barrier dysfunction through alpha 7 nicotinic receptors  

PubMed Central

Aim: To test whether carbachol can influence endothelial barrier dysfunction induced by tumor necrosis factor (TNF)-? and whether the alpha 7 nicotinic receptor can mediate this process. Methods: Rat cardiac microvascular endothelial cells were exposed to carbachol followed by TNF-? treatment in the presence or the absence of ?-bungarotoxin (an antagonist of the alpha 7 nicotinic receptor). Permeability of endothelial cells cultured on Transwell ?lters was assayed using FITC-albumin. F-actin was stained with FITC- phalloidin. Expression of vascular endothelial cadherin, intercellular adhesion molecule 1 (ICAM-1), phosphor-ERK1/2 and phosphor-JNK was detected using Western blot. Results: Carbachol (2 ?mol/L-2 mmol/L) prevented increase in endothelial cell permeability induced by TNF-? (500 ng/mL) in a dose-dependent manner. Further, it attenuated the down-regulation of vascular endothelial cadherin and the up-regulation of ICAM-1 induced by TNF-?. In addition, treatment of endothelial cells with carbachol decreased phosphor-ERK1/2 and phosphor-JNK. These effects of carbachol were blocked by ?-bungarotoxin 3 ?g/mL. Conclusion: These data suggest that the inhibitory effect of carbachol on TNF-?-induced endothelial barrier dysfunction mediated by the alpha 7 nicotinic receptor. PMID:20871620

Li, Yu-zhen; Liu, Xiu-hua; Rong, Fei; Hu, Sen; Sheng, Zhi-yong

2010-01-01

261

Nuclear receptor ERR? and coactivator PGC-1? are effectors of IFN-?-induced host defense  

PubMed Central

Macrophage activation by the proinflammatory cytokine interferon-? (IFN-?) is a critical component of the host innate response to bacterial pathogenesis. However, the precise nature of the IFN-?-induced activation pathway is not known. Here we show using genome-wide expression and chromatin-binding profiling that IFN-? induces the expression of many nuclear genes encoding mitochondrial respiratory chain machinery via activation of the nuclear receptor ERR? (estrogen-related receptor ?, NR3B1). Studies with macrophages lacking ERR? demonstrate that it is required for induction of mitochondrial reactive oxygen species (ROS) production and efficient clearance of Listeria monocytogenes (LM) in response to IFN-?. As a result, mice lacking ERR? are susceptible to LM infection, a phenotype that is localized to bone marrow-derived cells. Furthermore, we found that IFN-?-induced activation of ERR? depends on coactivator PGC-1? (peroxisome proliferator-activated receptor ? coactivator-1?), which appears to be a direct target for the IFN-?/STAT-1 signaling cascade. Thus, ERR? and PGC-1? act together as a key effector of IFN-?-induced mitochondrial ROS production and host defense. PMID:17671090

Sonoda, Junichiro; Laganiere, Josee; Mehl, Isaac R.; Barish, Grant D.; Chong, Ling-Wa; Li, Xiangli; Scheffler, Immo E.; Mock, Dennis C.; Bataille, Alain R.; Robert, Francois; Lee, Chih-Hao; Giguere, Vincent; Evans, Ronald M.

2007-01-01

262

Thyroid hormones and their nuclear receptors: new players in intestinal epithelium stem cell biology?  

PubMed

Thyroid hormones participate in the development and homeostasis of several organs and tissues. It is well documented that they act via nuclear receptors, the TRs, which are transcription factors whose function is modulated by the hormone T3. Importantly, T3-induced physiological response within a cell depends on the specific TR expression and on the T3 bioavailability. However, in addition to this T3-dependent control of TR functionality, increasing data show that the action of TRs is coordinated and integrated with other signaling pathways, specifically at the level of stem/progenitor cell populations. By focusing on the intestinal epithelium of both amphibians and mammals we summarize here new data in support of a role for thyroid hormones and the TR nuclear receptors in stem cell biology. This new concept may be extended to other organs and have biological relevance in therapeutic approaches aimed to target stem cells such as tissue engineering and cancer. PMID:24604390

Sirakov, Maria; Kress, Elsa; Nadjar, Julien; Plateroti, Michelina

2014-08-01

263

Effects of growth hormone antagonists on 3T3-F442A preadipocyte differentiation  

E-print Network

and undergo terminal differentiation into mature adipose cells. Many differentiation-related changes-term GH-inducible events were studied during adipose differ- entiation, including late marker gene. 1982, Nixon & Green 1984, Zezulak & Green 1986). When 3T3-F442A cells achieve quiescence, serum factors

Gu, Tingyue

264

Functional monoclonal antibody acts as a biased agonist by inducing internalization of metabotropic glutamate receptor 7  

PubMed Central

BACKGROUND AND PURPOSE The mGlu7 receptors are strategically located at the site of vesicle fusion where they modulate the release of the main excitatory and inhibitory neurotransmitters. Consequently, they are implicated in the underlying pathophysiology of CNS diseases such as epilepsy and stress-related psychiatric disorders. Here, we characterized a selective, potent and functional anti-mGlu7 monoclonal antibody, MAB1/28, that triggers receptor internalization. EXPERIMENTAL APPROACH MAB1/28's activity was investigated using Western blot and direct immunofluorescence on live cells, in vitro pharmacology by functional cAMP and [35S]-GTP? binding assays, the kinetics of IgG-induced internalization by image analysis, and the activation of the ERK1/2 by elisa. KEY RESULTS mGlu7/mGlu6 chimeric studies located the MAB1/28 binding site at the extracellular amino-terminus of mGlu7. MAB1/28 potently antagonized both orthosteric and allosteric agonist-induced inhibition of cAMP accumulation. The potency of the antagonistic actions was similar to the potency in triggering receptor internalization. The internalization mechanism occurred via a pertussis toxin-insensitive pathway and did not require G?i protein activation. MAB1/28 activated ERK1/2 with potency similar to that for receptor internalization. The requirement of a bivalent receptor binding mode for receptor internalizations suggests that MAB1/28 modulates mGlu7 dimers. CONCLUSIONS AND IMPLICATIONS We obtained evidence for an allosteric-biased agonist activity triggered by MAB1/28, which activates a novel IgG-mediated GPCR internalization pathway that is not utilized by small molecule, orthosteric or allosteric agonists. Thus, MAB1/28 provides an invaluable biological tool for probing mGlu7 function and selective activation of its intracellular trafficking. PMID:22747985

Ullmer, C; Zoffmann, S; Bohrmann, B; Matile, H; Lindemann, L; Flor, PJ; Malherbe, P

2012-01-01

265

Expression of netrin-1 receptors in retina of oxygen-induced retinopathy in mice  

PubMed Central

Background Netrin-1 has been reported to promote retinal neovascularization in oxygen-induced retinopathy (OIR). However, netrin-1 receptors, which may mediate netrin-1 action during retinal neovascularization, have not been characterized. In this study, we investigated netrin-1 receptor subtype expression and associated changes in the retinas of mice with OIR. Methods C57BL/6J mice were exposed to 75±2% oxygen for 5 days and then returned to normal air to induce retinal neovascularization. Reverse transcriptase polymerase chain reaction (RT-PCR) and Western blot were used to examine the expression of netrin-1 receptor subtypes in the mouse retinas. Double staining of netrin-1 receptor subtypes and isolectin B4 was used to determine the location of the netrin-1 receptor subtypes in the retinas. Inhibition of retinal neovascularization was achieved by UNC5B shRNA plasmid intravitreal injection. Retinal neovascularization was examined by fluorescein angiography and quantification of preretinal neovascular nuclei in retinal sections. Results RT-PCR results showed that, except for UNC5A, netrin-1 receptor subtypes UNC5B, UNC5C, UNC5D, DCC, neogenin, and A2b were all expressed in the retinas of OIR mice 17 days after birth. Western blots showed that only UNC5B expression was significantly increased on that day, and immunofluorescence results showed that only UNC5B and neogenin were expressed in retinal vessels. Treatment of OIR mice with the UNC5B shRNA plasmid dramatically reduced neovascular tufts and neovascular outgrowth into the inner limiting membrane. Conclusions UNC5B may promote retinal neovascularization in OIR mice. PMID:25149138

2014-01-01

266

Prostatic relaxation induced by loperamide is mediated through activation of opioid ?-2 receptors in vitro  

PubMed Central

The merit of opioid ?-receptor activation in the improvement of benign prostatic hyperplasia (BPH) remains obscure. In the present study, we used loperamide to identify the subtype of opioid ?-receptors involved in prostatic relaxation and investigate the possible mechanism of this relaxation. Prostate strips were isolated from 12-week-old male Wistar rats for identification of isometric tension. The prostate strips were precontracted with either 1 ?mol/l phenylephrine or 50 mmol/l KCl. The decrease in muscle tone (relaxation) was then characterized after cumulative administration of loperamide (0.1 to 10 ?mol/l) into the organ bath for the concentration-dependent study. Pretreatment with specific blockers or antagonists was carried out to compare the changes in loperamide-induced relaxation. Loperamide produced a marked relaxation in the isolated prostates precontracted with phenylephrine or KCl in a dose-dependent manner. This relaxation was abolished by cyprodime, a selective opioid ?-receptor antagonist, but was not modified by naloxonazine at a dose sufficient to block the opioid ?-1 receptors. Treatment with an agonist for opioid ?-1 receptors also failed to modify the muscle tone. Moreover, the relaxation by loperamide was attenuated by glibenclamide at a dose sufficient to block ATP-sensitive K+ channels. In addition, this action of loperamide was abolished by protein kinase A (PKA) inhibitor and enhanced by the inhibitor of phosphodiesterase for cyclic AMP (cAMP). Our results suggest that loperamide induces prostatic relaxation through activation of opioid ?-2 receptors via the cAMP-PKA pathway to open ATP-sensitive K+ channels. PMID:22977498

LU, CHIH-CHENG; CHUNG, HSIEN-HUI; CHENG, JUEI-TANG

2011-01-01

267

Differential reelin-induced enhancement of NMDA and AMPA receptor activity in the adult hippocampus.  

PubMed

The developmental lamination of the hippocampus and other cortical structures requires a signaling cascade initiated by reelin and its receptors, apoER2 (apolipoprotein E receptor 2) and VLDLR (very-low-density lipoprotein receptor). However, the functional significance of continued reelin expression in the postnatal brain remains poorly understood. Here, we show that reelin application to adult mice hippocampal slices leads to enhanced glutamatergic transmission mediated by NMDA receptors (NMDARs) and AMPA receptors (AMPARs) through distinct mechanisms. Application of recombinant reelin enhanced NMDAR-mediated currents through postsynaptic mechanisms, as revealed by the variance-mean analysis of synaptic NMDAR currents, assessment of spontaneous miniature events, and the levels of NMDAR subunits at synaptic surface. In comparison, nonstationary fluctuation analysis of miniature AMPAR currents and quantification of synaptic surface proteins revealed that reelin-induced enhancement of AMPAR responses was mediated by increased AMPAR numbers. Reelin enhancement of synaptic NMDAR currents was abolished when receptor-associated protein (RAP) or the Src inhibitor 4-amino-5-(4-methylphenyl)-7-(t-butyl)pyrazolo[3,4-d]-pyrimidine (PP1) was bath applied and was abrogated by including PP1 in the recording electrodes. In comparison, including RAP or an inactive PP1 analog PP3 in the recording electrode was without effect. Interestingly, the increased AMPAR response after reelin application was not blocked by PP1 but was blocked by the phosphoinositide-3' kinase (PI3K) inhibitors wortmannin and LY294002 [2-(4-morpholinyl)-8-phenyl-1(4H)-benzopyran-4-one hydrochloride]. Furthermore, reelin-induced, PI3K-dependent AMPAR surface insertion was also observed in cultured hippocampal neurons. Together, these results reveal a differential functional coupling of reelin signaling with NMDAR and AMPAR function and define a novel mechanism for controlling synaptic strength and plasticity in the adult hippocampus. PMID:17167084

Qiu, Shenfeng; Zhao, Lisa F; Korwek, Kimberly M; Weeber, Edwin J

2006-12-13

268

Activation of Peroxisome Proliferator-Activated Receptor ?/? Induces Lung Cancer Growth via Peroxisome Proliferator-Activated Receptor Coactivator ?-1?  

PubMed Central

We previously demonstrated that a selective agonist of peroxisome proliferator–activated receptor ?/? (PPAR?/?), GW501516, stimulated human non–small cell lung carcinoma (NSCLC) growth, partly through inhibition of phosphatase and tensin homolog deleted on chromosome 10 expression. Here, we show that GW501516 also decreases the phosphorylation of AMP-activated protein kinase ? (AMPK?), a major regulator of energy metabolism. This was mediated through specific activation of PPAR?/?, as a PPAR?/? small interfering RNA inhibited the effect. However, AMPK? did not mediate the growth-promoting effects of GW501516, as silencing of AMPK? did not inhibit GW501516-induced cell proliferation. Instead, we found that GW501516 stimulated peroxisome proliferator–activated receptor coactivator ? (PGC)-1?, which activated the phosphatidylinositol 3 kinase (PI3-K)/Akt mitogenic pathway. An inhibitor of PI3-K, LY294002, had no effect on PGC-1?, consistent with PGC-1? being upstream of PI3-K/Akt. Of note, an activator of AMPK?, 5-amino-4-imidazole carboxamide riboside, inhibited the growth-promoting effects of GW501516, suggesting that although AMPK? is not responsible for the mitogenic effects of GW501516, its activation can oppose these events. This study unveils a novel mechanism by which GW501516 and activation of PPAR?/? stimulate human lung carcinoma cell proliferation, and suggests that activation of AMPK? may oppose this effect. PMID:18776129

Han, ShouWei; Ritzenthaler, Jeffrey D.; Sun, XiaoJuan; Zheng, Ying; Roman, Jesse

2009-01-01

269

Peroxisome proliferator-activated receptor ? confers resistance to peroxisome proliferator-activated receptor ?-induced apoptosis in colorectal cancer cells  

PubMed Central

Peroxisome proliferator-activated receptor ? (PPAR?) may serve as a useful target for drug development in non-diabetic diseases. However, some colorectal cancer cells are resistant to PPAR? agonists by mechanisms that are poorly understood. Here we provide the first evidence that elevated PPAR? expression and/or activation of PPAR? antagonize the ability of PPAR? to induce colorectal carcinoma cell death. More importantly, the opposing effects of PPAR? and PPAR? in regulating programmed cell death are mediated by survivin and caspase-3. We found that activation of PPAR? results in decreased survivin expression and increased caspase-3 activity, whereas activation of PPAR? counteracts these effects. Our findings suggest that PPAR? and PPAR? coordinately regulate cancer cell fate by controlling the balance between the cell death and survival and demonstrate that inhibition of PPAR? can reprogram PPAR? ligand-resistant cells to respond to PPAR? agonists. PMID:21765467

Wang, Dingzhi; Ning, Wei; Xie, Dianren; Guo, Lixia; DuBois, Raymond N.

2014-01-01

270

Peroxisome proliferator-activated receptor ? confers resistance to peroxisome proliferator-activated receptor ?-induced apoptosis in colorectal cancer cells.  

PubMed

Peroxisome proliferator-activated receptor ? (PPAR?) may serve as a useful target for drug development in non-diabetic diseases. However, some colorectal cancer cells are resistant to PPAR? agonists by mechanisms that are poorly understood. Here, we provide the first evidence that elevated PPAR? expression and/or activation of PPAR? antagonize the ability of PPAR? to induce colorectal carcinoma cell death. More importantly, the opposing effects of PPAR? and PPAR? in regulating programmed cell death are mediated by survivin and caspase-3. We found that activation of PPAR? results in decreased survivin expression and increased caspase-3 activity, whereas activation of PPAR? counteracts these effects. Our findings suggest that PPAR? and PPAR? coordinately regulate cancer cell fate by controlling the balance between the cell death and survival and demonstrate that inhibition of PPAR? can reprogram PPAR? ligand-resistant cells to respond to PPAR? agonists. PMID:21765467

Wang, D; Ning, W; Xie, D; Guo, L; DuBois, R N

2012-02-23

271

PICK1 Mediates Synaptic Recruitment of AMPA Receptors at Neurexin-Induced Postsynaptic Sites.  

PubMed

In the CNS, synapse formation and maturation play crucial roles in the construction and consolidation of neuronal circuits. Neurexin and neuroligin localize on the opposite sides of synaptic membrane and interact with each other to promote the assembly and specialization of synapses. However, the excitatory synapses induced by the neurexin-neuroligin complex are initially immature synapses that lack AMPA receptors. Previously, PICK1 (protein interacting with C kinase 1) was shown to cluster and regulate the synaptic localization of AMPA receptors. Here, we report that during synaptogenesis induced by neurexin in cultured neurons from rat hippocampus, PICK1 recruited AMPA receptors to immature postsynaptic sites. This synaptic recruitment of AMPA receptors depended on the interaction between GluA2 and PICK1, and on the lipid-binding ability of PICK1, but not the interaction between PICK1 and neuroligin. Last, our results demonstrated that the recruitment of GluA2 to synapses could be prevented by ICA69 (islet cell autoantigen 69 kDa), a key binding partner of PICK1. Our study showed that PICK1, being negatively regulated by ICA69, could facilitate synapse maturation. PMID:25392508

Xu, Junyu; Kam, Chuen; Luo, Jian-Hong; Xia, Jun

2014-11-12

272

Autoimmune-induced glutamatergic receptor dysfunctions: conceptual and psychiatric practice implications.  

PubMed

Glutamatergic neurotransmission is mediated via complex receptorial systems including N-methyl-d-aspartate (NMDA), alpha-amino-3-hydroxy-5-methyl-4-isoxazolpropionic acid (AMPA) and metabotropic receptor subtypes and plays a critical role in the modulation of synaptic plasticity, mood, cognitive processes and motor behavior. Glutamatergic function deficits are hypothesized to contribute to the pathogenesis of neuropsychiatric disorders, including schizophrenia, mood and movement disorders. Accumulating data are rapidly leading to the characterization of specific types of autoimmune encephalitis in which the receptors and proteins critically involved in glutamatergic neurotransmission, e.g., NMDA, AMPA receptors, are antigen targets. Characteristic of these syndromes, antibodies alter the structure and/or function of the corresponding neuronal antigen resulting in clinical pictures that resemble pharmacological disease models. Presently the best characterized autoimmune glutamatergic disorder is anti-NMDA receptor encephalitis. This disorder manifests with intertwined psychiatric and neurological features, defines a new syndrome, reclassifies poorly defined clinical states and extends previous hypotheses, such as hypo-NMDA receptor function in schizophrenia. The characterization of autoimmune-induced glutamatergic receptor dysfunctions (AGRD) is likely to have a substantial conceptual impact upon our understanding of neuropsychiatric disorders including schizophrenia, affective and movement dysfunctions. Further definition of AGRD will provide additional guidelines for psychiatric diagnoses, identification of homogeneous patient subtypes within broad phenomenological classifications and will contribute to the development of personalized treatments. The body of knowledge already accumulated on anti-NMDA receptor encephalitis highlights the need for wide dissemination of these concepts among psychiatrists, and in suspected cases, for early recognition, prompt clinical and laboratory investigation and efficient interface between mental health and medical teams. PMID:23791073

Rosenthal-Simons, Ayelet; Durrant, Andrea R; Heresco-Levy, Uriel

2013-12-01

273

Tamoxifen counteracts estradiol induced effects on striatal and hypophyseal dopamine receptors  

SciTech Connect

We investigated the ability of Tamoxifen (TAM), an antiestrogen drug, to counteract the modification induced by estrogens on dopamine (DA) receptors on striatum and on adenohypophysis of ovex female rats. Subacute treatment with 17..beta..-estradiol (E/sub 2/) at both low (0.1 ..mu..g/kg) and high (20 ..mu..g/kg) doses confirmed its ability to increase the number of striatal /sup 3/H-Spiperone (/sup 3/H-SPI) binding sites in a dose dependent manner. By contrast in the pituitary, only high doses of estrogen were effective in reducing the number of DA receptors. We treated ovex female rats for 15 days with TAM alone or associated with E/sub 2/, to see if these estrogenic effects could be suppressed by an antiestrogenic drug. TAM did not affect the number of striatal DA receptors, but significantly increased the adenohypophy-seal DA binding sites, without varying their affinity. No changes were observed in pituitary and striatal DA receptor density, even when TAM was injected in association with estradiol. In conclusions: TAM is able to counteract the effects estrogens have on DA receptors. However there is some evidence that it could influence the pituitary DA systems independently of it antiestrogenic activity.

Ferretti, C.; Blengio, M.; Ghi, P.; Racca, S.; Genazzani, E.; Portaleone, P.

1988-01-01

274

Central Resistin Overexposure Induces Insulin Resistance Through Toll-Like Receptor 4  

PubMed Central

Resistin promotes both inflammation and insulin resistance associated with energy homeostasis impairment. However, the resistin receptor and the molecular mechanisms mediating its effects in the hypothalamus, crucial for energy homeostasis control, and key insulin-sensitive tissues are still unknown. In the current study, we report that chronic resistin infusion in the lateral cerebral ventricle of normal rats markedly affects both hypothalamic and peripheral insulin responsiveness. Central resistin treatment inhibited insulin-dependent phosphorylation of insulin receptor (IR), AKT, and extracellular signal–related kinase 1/2 associated with reduced IR expression and with upregulation of suppressor of cytokine signaling-3 and phosphotyrosine phosphatase 1B, two negative regulators of insulin signaling. Additionally, central resistin promotes the activation of the serine kinases Jun NH2-terminal kinase and p38 mitogen-activated protein kinase, enhances the serine phosphorylation of insulin receptor substrate-1, and increases the expression of the proinflammatory cytokine interleukin-6 in the hypothalamus and key peripheral insulin-sensitive tissues. Interestingly, we also report for the first time, to our knowledge, the direct binding of resistin to Toll-like receptor (TLR) 4 receptors in the hypothalamus, leading to the activation of the associated proinflammatory pathways. Taken together, our findings clearly identify TLR4 as the binding site for resistin in the hypothalamus and bring new insight into the molecular mechanisms involved in resistin-induced inflammation and insulin resistance in the whole animal. PMID:22961082

Benomar, Yacir; Gertler, Arieh; De Lacy, Pamela; Crepin, Delphine; Ould Hamouda, Hassina; Riffault, Laure; Taouis, Mohammed

2013-01-01

275

Inhibition by Chondroitin Sulfate E Can Specify Functional Wnt/?-Catenin Signaling Thresholds in NIH3T3 Fibroblasts*  

PubMed Central

Aberrant activation of the Wnt/?-catenin signaling pathway is frequently associated with human disease, including cancer, and thus represents a key therapeutic target. However, Wnt/?-catenin signaling also plays critical roles in many aspects of normal adult tissue homeostasis. The identification of mechanisms and strategies to selectively inhibit the disease-related functions of Wnt signaling, while preserving normal physiological functions, is in its infancy. Here, we report the identification of exogenous chondroitin sulfate-E (CS-E) as an inhibitor of specific molecular and biological outcomes of Wnt3a signaling in NIH3T3 fibroblasts. We demonstrate that CS-E can decrease Wnt3a signaling through the negative regulation of LRP6 receptor activation. However, this inhibitory effect of CS-E only affected Wnt3a-mediated induction, but not repression, of target gene expression. We went on to identify a critical Wnt3a signaling threshold that differentially affects target gene induction versus repression. This signaling threshold also controlled the effects of Wnt3a on proliferation and serum starvation-induced apoptosis. Limiting Wnt3a signaling to this critical threshold, either by CS-E treatment or by ligand dilution, interfered with Wnt3a-mediated stimulation of proliferation but did not impair Wnt3a-mediated reduction of serum starvation-induced apoptosis. Treatment with pharmacological inhibitors demonstrated that both induction and repression of Wnt3a target genes in NIH3T3 cells require the canonical Wnt/?-catenin signaling cascade. Our data establish the feasibility of selective inhibition of Wnt/?-catenin transcriptional programs and biological outcomes through the exploitation of intrinsic signaling thresholds. PMID:22915582

Willis, Catherine M.; Kluppel, Michael

2012-01-01

276

Regulation of cell differentiation by hNUDC via a Mpl-dependent mechanism in NIH 3T3 cells  

SciTech Connect

Thrombopoietin receptor (Mpl) belongs to the cytokine receptor surperfamily with a large extracellular N-terminal portion responsible for cytokine recognition and binding. Thrombopoietin (TPO) has so far been the only widely studied cytokine for Mpl. However we have recently identified human NUDC (hNUDC), previously described as a human homolog of a fungal nuclear migration protein, as another putative binding partner of Mpl. The purpose of this study is to test the extent of the functioning of hNUDC by identifying protein-protein interactions with Mpl in mammalian cells. The full-length cDNAs encoding Mpl and hNUDC were cloned into pEGFP-N1 and pDsRed2-N1 respectively which were subsequently expressed as Mpl-EGFP (green) and hNUDC-DsRed (red) fusion proteins. Using ELISA and immunofluorescence studies, we have demonstrated the direct binding of hNUDC to cell surface-captured Mpl. We also observed that hNUDC induced significant changes in cellular morphology in NIH 3T3 cells stably transfected with pMpl-EGFP. Interestingly, these morphological changes were characteristic of cells undergoing megakaryocyte differentiation. Extracellular-signal-regulated protein kinases 1 and 2 (ERK1/2) have been shown to mediate such megakaryocyte-like differentiation. In addition, co-expression of Mpl-EGFP and hNUDC-DsRed led to the release of hNUDC-DsRed into the culture medium.

Zhang Yuping; Tang Yongsong; Chen Xushen [State Key Laboratory of Biocontrol and Key Laboratory of Gene Engineering of Education Ministry, Zhongshan University, Guangzhou 510275 (China); Xu Peilin [State Key Laboratory of Biocontrol and Key Laboratory of Gene Engineering of Education Ministry, Zhongshan University, Guangzhou 510275 (China)], E-mail: xupeilin@hotmail.com

2007-09-10

277

Cannabinoid-Induced Mesenteric Vasodilation through an Endothelial Site Distinct from CB1 or CB2 Receptors  

Microsoft Academic Search

Cannabinoids, including the endogenous ligand arachidonyl ethanolamide (anandamide), elicit not only neurobehavioral but also cardiovascular effects. Two cannabinoid receptors, CB1 and CB2, have been cloned, and studies with the selective CB1 receptor antagonist SR141716A have implicated peripherally located CB1 receptors in the hypotensive action of cannabinoids. In rat mesenteric arteries, anandamide-induced vasodilation is inhibited by SR141716A, but other potent CB1

Zoltan Jarai; Jens A. Wagner; Karoly Varga; Kristy D. Lake; David R. Compton; Billy R. Martin; Anne M. Zimmer; Tom I. Bonner; Nancy E. Buckley; Eva Mezey; Raj K. Razdan; Andreas Zimmer; George Kunos

1999-01-01

278

Activation of spinal ?2 adrenergic receptors induces hyperglycemia in mouse though activating sympathetic outflow.  

PubMed

The roles of ?2-adrenergic receptors located in the spinal cord in the regulation of blood glucose levels were studied in imprinting control region (ICR) mice. Mice were treated intrathecally (i.t.) with clonidine or yohimbine, and the blood glucose levels were measured at 0, 30, 60 and 120min after i.t. administration. The i.t. injection with clonidine caused a pronounced elevation of the blood glucose levels in a dose-dependent manner. Clonidine-induced hyperglycemic effect was dose-dependently attenuated by i.t. pretreatment with yohimbine. Furthermore, plasma insulin level was attenuated by clonidine, and yohimbine pretreatment reversed partially, but significantly, clonidine-induced down-regulation of the plasma insulin level. I.t. pretreatment with pertussis toxin (PTX) almost abolished the hyperglycemic effect induced by clonidine. PTX pretreatment reversed the induced down-regulation of the insulin level. In addition, i.t. pretreatment with N-(2-chloroethyl)-N-ethyl-2-bromobenzylamine (DSP-4) or intraperitoneal (i.p.) pretreatment with mifepristone, hexamethonium and 6-hydroxydopamine (6-OHDA) attenuated the hyperglycemic effect induced by clonidine. I.t. injected clonidine significantly increased plasma corticosterone level. The elevated blood glucose level induced by clonidine was significantly decreased in adrenalectomized (ADX) mice. Our results suggest that the ?2-adrenergic receptors located in the spinal cord play important roles for the elevation of the blood glucose level. The hyperglycemic effect induced by clonidine appears to be mediated by a reduction of the plasma insulin level. In addition, glucocortioid system appears to be involved in clonidine-induced hyperglycemic effect. Furthermore, the clonidine-induced hyperglycemia appears to be mediated via activating the spinal nerves or peripheral sympathetic nervous system. PMID:25179570

Sim, Yun-Beom; Park, Soo-Hyun; Kim, Sung-Su; Lim, Su-Min; Jung, Jun-Sub; Suh, Hong-Won

2014-10-15

279

Original article Triiodothyronine (T3), insulin and characteristics  

E-print Network

in mare's colostrum and milk during the first 21 days of lactation were measured. Post partum, T3 in colostrum and milk of the mare. © Inra/Elsevier, Paris triiodothyronine in milk / insulin in milk / 5'Ă©volution, pendant les 21 jours post-partum des concen- trations d'insuline et de T3 dans le colostrum, et de l

Paris-Sud XI, Université de

280

Soluble Forms of the Notch Ligands Delta1 and Jagged1 Promote in Vivo Tumorigenicity in NIH3T3 Fibroblasts with Distinct Phenotypes  

PubMed Central

We previously found that soluble forms of the Notch ligands Jagged1 and Delta1 induced fibroblast growth factor receptor-dependent cell transformation in NIH3T3 fibroblasts. However, the phenotypes of these lines differed, indicating distinct functional differences among these Notch ligands. In the present study, we used allografts to test the hypothesis that NIH3T3 fibroblasts that express soluble forms of Delta1 and Jagged1 accelerate tumorigenicity in vivo. With the exception of the full-length Jagged1 transfectant, all other cell lines, including the control, generated tumors when injected subcutaneously in athymic mice. Suppression of Notch signaling by the soluble ligands significantly increased tumor onset and growth, whereas full-length Jagged1 completely suppressed tumor development. In addition, there were striking differences in tumor pathology with respect to growth kinetics, vascularization, collagen content, size and number of necrotic foci, and invasiveness into the underlying tissue. Further, the production of angiogenic factors, including vascular endothelial growth factor, also differed among the tumor types. Lastly, both Jagged1- and Delta1-derived tumors contained phenotypically distinct populations of lipid-filled cells that corresponded with increased expression of adipocyte markers. The divergence of tumor phenotype may be attributed to ligand-specific alterations in Notch receptor responses in exogenous and endogenous cell populations within the allographs. Our findings demonstrate distinct functional properties for these Notch ligands in the promotion of tumorigenicity in vivo. PMID:18688026

Urs, Sumithra; Roudabush, Alice; O'Neill, Christine F.; Pinz, Ilka; Prudovsky, Igor; Kacer, Doreen; Tang, Yuefang; Liaw, Lucy; Small, Deena

2008-01-01

281

Estradiol inhibits glucocorticoid receptor expression and induces glucocorticoid resistance in MCF7 human breast cancer cells  

Microsoft Academic Search

Our study has shown that treatment of MCF-7 human breast cancer cells with 17-? estradiol (E2) produced significant decreases in glucocorticoid receptor (GR) concentrations and GR mRNA levels. E2 pre-treatment of MCF-7 cells stably transfected with the GR responsive pMTV-CAT reporter (MCF-7–MTV cells), caused significant attenuation of dexamethasone (DEX)-induced chloramphenicol acetyl transferase (CAT). In MCF-7 cells transiently transfected with [(GRE)3-Luc

Aruna V Krishnan; Srilatha Swami; David Feldman

2001-01-01

282

Angiotensin II Receptor Blocker, Losartan, Ameliorates Gentamicin-Induced Oxidative Stress and Nephrotoxicity in Rats  

Microsoft Academic Search

Background\\/Aims: This study investigates the ameliorative effect of concurrent and pretreatment with angiotensin II receptor blocker, losartan (LOS), against gentamicin (GEN)-induced renal damage. Methods: Rats were divided into five groups: control, LOS group (10 mg\\/kg\\/day for 7 days), GEN group (100 mg\\/kg\\/day for 7 days), GEN + LOS pretreated group (treated with LOS for 7 days followed by 7 days

Gehan H. Heeba

2011-01-01

283

Guanylin and uroguanylin induce natriuresis in mice lacking guanylyl cyclase-C receptor  

Microsoft Academic Search

Guanylin and uroguanylin induce natriuresis in mice lacking guanylyl cyclase-C receptor.BackgroundGuanylin (GN) and uroguanylin (UGN) are intestinally derived peptide hormones that are similar in structure and activity to the diarrhea-causing Escherichia coli heat-stable enterotoxins (STa). These secretagogues have been shown to affect fluid, Na+, K+, and Cl? transport in both the intestine and kidney, presumably by intracellular cyclic guanosine monophosphate

Stephen L. Carrithers; Cobern E. Ott; Michael J. Hill; Brett R. Johnson; WEIYAN CAI; Jason J. Chang; Rajesh G. Shah; CONGMEI SUN; Elizabeth A. Mann; Manasses C. Fonteles; Leonard R. Forte; Brian A. Jackson; Ralph A. Giannella; Richard N. Greenberg

2004-01-01

284

Agrin-induced acetylcholine receptor clustering in mammalian muscle requires tyrosine phosphorylation  

Microsoft Academic Search

Agrin is thought to be the nerve-derived fac- tor that initiates acetylcholine receptor (AChR) clus- tering at the developing neuromuscular junction. We have investigated the signaling pathway in mouse C2 myotubes and report that agrin induces a rapid but transient tyrosine phosphorylation of the AChR 13 sub- unit. As the 13-subunit tyrosine phosphorylation occurs before the formation of AChR clusters,

Michael Ferns; Michael Deiner; Zach Hall

1996-01-01

285

Molecular mechanism of 17-allylamino-17-demethoxygeldanamycin (17-AAG)-induced AXL receptor tyrosine kinase degradation.  

PubMed

The receptor tyrosine kinase AXL is overexpressed in many cancer types including thyroid carcinomas and has well established roles in tumor formation and progression. Proper folding, maturation, and activity of several oncogenic receptor tyrosine kinases require HSP90 chaperoning. HSP90 inhibition by the antibiotic geldanamycin or its derivative 17-allylamino-17-demethoxygeldanamycin (17-AAG) causes destabilization of its client proteins. Here we show that AXL is a novel client protein of HSP90. 17-AAG induced a time- and dose-dependent down-regulation of endogenous or ectopically expressed AXL protein, thereby inhibiting AXL-mediated signaling and biological activity. 17-AAG-induced AXL down-regulation specifically affected fully glycosylated mature receptor present on cell membrane. By using biotin and [(35)S]methionine labeling, we showed that 17-AAG caused depletion of membrane-localized AXL by mediating its degradation in the intracellular compartment, thus restricting its exposure on the cell surface. 17-AAG induced AXL polyubiquitination and subsequent proteasomal degradation; under basal conditions, AXL co-immunoprecipitated with HSP90. Upon 17-AAG treatment, AXL associated with the co-chaperone HSP70 and the ubiquitin E3 ligase carboxyl terminus of HSC70-interacting protein (CHIP). Overexpression of CHIP, but not of the inactive mutant CHIP K30A, induced accumulation of AXL polyubiquitinated species upon 17-AAG treatment. The sensitivity of AXL to 17-AAG required its intracellular domain because an AXL intracellular domain-deleted mutant was insensitive to the compound. Active AXL and kinase-dead AXL were similarly sensitive to 17-AAG, implying that 17-AAG sensitivity does not require receptor phosphorylation. Overall our data elucidate the molecular basis of AXL down-regulation by HSP90 inhibitors and suggest that HSP90 inhibition in anticancer therapy can exert its effect through inhibition of multiple kinases including AXL. PMID:23629654

Krishnamoorthy, Gnana Prakasam; Guida, Teresa; Alfano, Luigi; Avilla, Elvira; Santoro, Massimo; Carlomagno, Francesca; Melillo, Rosa Marina

2013-06-14

286

Dopamine D4 Receptor Counteracts Morphine-Induced Changes in ? Opioid Receptor Signaling in the Striosomes of the Rat Caudate Putamen  

PubMed Central

The mu opioid receptor (MOR) is critical in mediating morphine analgesia. However, prolonged exposure to morphine induces adaptive changes in this receptor leading to the development of tolerance and addiction. In the present work we have studied whether the continuous administration of morphine induces changes in MOR protein levels, its pharmacological profile, and MOR-mediated G-protein activation in the striosomal compartment of the rat CPu, by using immunohistochemistry and receptor and DAMGO-stimulated [35S]GTP?S autoradiography. MOR immunoreactivity, agonist binding density and its coupling to G proteins are up-regulated in the striosomes by continuous morphine treatment in the absence of changes in enkephalin and dynorphin mRNA levels. In addition, co-treatment of morphine with the dopamine D4 receptor (D4R) agonist PD168,077 fully counteracts these adaptive changes in MOR, in spite of the fact that continuous PD168,077 treatment increases the [3H]DAMGO Bmax values to the same degree as seen after continuous morphine treatment. Thus, in spite of the fact that both receptors can be coupled to Gi/0 protein, the present results give support for the existence of antagonistic functional D4R-MOR receptor-receptor interactions in the adaptive changes occurring in MOR of striosomes on continuous administration of morphine. PMID:24451133

Suarez-Boomgaard, Diana; Gago, Belen; Valderrama-Carvajal, Alejandra; Roales-Bujan, Ruth; Van Craenenbroeck, Kathleen; Duchou, Jolien; Borroto-Escuela, Dasiel O.; Medina-Luque, Jose; de la Calle, Adelaida; Fuxe, Kjell; Rivera, Alicia

2014-01-01

287

"Hijacking" the thyrotropin receptor: A chimeric receptor-lysosome associated membrane protein enhances deoxyribonucleic acid vaccination and induces Graves' hyperthyroidism.  

PubMed

Naked DNA vaccination with the TSH receptor (TSHR) does not, in most studies, induce TSHR antibodies and never induces hyperthyroidism in BALB/c mice. Proteins expressed endogenously by vaccination are preferentially presented by major histocompatibility complex class I, but optimal T cell help for antibody production requires lysosomal processing and major histocompatibility complex class II presentation. To divert protein expression to lysosomes, we constructed a plasmid with the TSHR ectodomain spliced between the signal peptide and transmembrane-intracellular region of lysosome-associated membrane protein (LAMP)-1, a lysosome-associated membrane protein. BALB/c mice pretreated with cardiotoxin were primed intramuscularly using this LAMP-TSHR chimera and boosted twice with DNA encoding wild-type TSHR, TSHR A-subunit, or LAMP-TSHR. With each protocol, spleen cells responded to TSHR antigen by secreting interferon-gamma, and 60% or more mice had TSHR antibodies detectable by ELISA. TSH binding inhibitory activity was present in seven, four, and two of 10 mice boosted with TSHR A-subunit, LAMP-TSHR, or wild-type TSHR, respectively. Importantly, six of 30 mice had elevated T4 levels and goiter (5 of 6 with detectable thyroid-stimulating antibodies). Injecting LAMP-TSHR intradermally without cardiotoxin pretreatment induced TSHR antibodies detectable by ELISA but not by TSH binding inhibitory activity, and none became hyperthyroid. These findings are consistent with a role for cardiotoxin-recruited macrophages in which (unlike in fibroblasts) LAMP-TSHR can be expressed intracellularly and on the cell surface. In conclusion, hijacking the TSHR to lysosomes enhances T cell responses and TSHR antibody generation and induces Graves'-like hyperthyroidism in BALB/c mice by intramuscular naked DNA vaccination. PMID:15331574

Pichurin, Pavel N; Chazenbalk, Gregorio D; Aliesky, Holly; Pichurina, Oxana; Rapoport, Basil; McLachlan, Sandra M

2004-12-01

288

Possible involvement of 5-HT4 receptors, in addition to 5-HT3 receptors, in the emesis induced by high-dose cisplatin in Suncus murinus.  

PubMed

To clarify the mechanism for the severe emesis concomitant with intensive chemotherapy, we investigated the effects of 5-HT3- and 5-HT4-receptor antagonists on the emesis induced by the high-dose of cisplatin in Suncus murinus. The emesis induced by 50 mg/kg of cisplatin was reduced by the oral pretreatment with tropisetron, which is known as a 5-HT3- and 5-HT4-receptor dual antagonist in vitro, with the ID50 value of 0.52 mg/kg. On the contrary, granisetron, a selective 5-HT3-receptor antagonist, did not markedly inhibit the emesis at up to 30 mg/kg. Moreover, GR125487, a selective 5-HT4-receptor antagonist, did not inhibit the emesis. However, co-administration of GR125487 and granisetron significantly reduced the number of emetic episodes. The study of the co-administration of GR125487 with tropisetron showed that GR125487 did not further enhance the inhibitory effect of tropisetron alone, suggesting that the anti-emetic effect of tropisetron is mediated via the blockade of both 5-HT3 and 5-HT4 receptors. These results suggest that both the 5-HT3 and 5-HT4 receptors are involved in the emesis induced by the high-dose of cisplatin in Suncus murinus. PMID:11243577

Horikoshi, K; Yokoyama, T; Kishibayashi, N; Ohmori, K; Ishii, A; Karasawa, A

2001-01-01

289

Elevated Expression of Liver X Receptor Alpha (LXR?) in Myocardium of Streptozotocin-Induced Diabetic Rats  

Microsoft Academic Search

The present study was designed to investigate the myocardial expression of liver X receptor alpha (LXR?) in a streptozotocin\\u000a (STZ)-induced diabetic rat model. Immunohistochemical staining, quantitative real-time RT-PCR, and Western blot analysis were\\u000a used to determine the expression of LXR? in the myocardium of STZ-induced diabetic rats. The myocardial expression of LXR?\\u000a target genes, long-chain acyl-CoA synthetase 3 (ACSL3), fatty

Yongxia Cheng; Guibo Liu; Qian Pan; Sufen Guo; Xianghong Yang

290

The Trifunctional Protein Mediates Thyroid Hormone Receptor-Dependent Stimulation of Mitochondria Metabolism  

PubMed Central

We previously demonstrated that the thyroid hormone, T3, acutely stimulates mitochondrial metabolism in a thyroid hormone receptor (TR)-dependent manner. T3 has also recently been shown to stimulate mitochondrial fatty acid oxidation (FAO). Here we report that TR-dependent stimulation of metabolism is mediated by the mitochondrial trifunctional protein (MTP), the enzyme responsible for long-chain FAO. Stimulation of FAO was significant in cells that expressed a nonnuclear amino terminus shortened TR isoform (sTR43) but not in adult fibroblasts cultured from mice deficient in both TR? and TR? isoforms (TR??/???/?). Mouse embryonic fibroblasts deficient in MTP (MTP?/?) did not support T3-stimulated FAO. Inhibition of fatty-acid trafficking into mitochondria using the AMP-activated protein kinase inhibitor 6-[4-(2-piperidin-1-yl-ethoxy)-phenyl)]-3-pyridin-4-yl-pyrrazolo[1,5-a]-pyrimidine (compound C) or the carnitine palmitoyltransferase 1 inhibitor etomoxir prevented T3-stimulated FAO. However, T3 treatment could increase FAO when AMP-activated protein kinase was maximally activated, indicating an alternate mechanism of T3-stimulated FAO exists, even when trafficking is presumably high. MTP? protein levels and higher molecular weight complexes of MTP subunits were increased by T3 treatment. We suggest that T3-induced increases in mitochondrial metabolism are at least in part mediated by a T3-shortened TR isoform-dependent stabilization of the MTP complex, which appears to lower MTP subunit turnover. PMID:22570332

Chocron, E. Sandra; Sayre, Naomi L.; Holstein, Deborah; Saelim, Nuttawut; Ibdah, Jamal A.; Dong, Lily Q.; Zhu, Xuguang; Cheng, Sheue-Yann

2012-01-01

291

Chronic Administration of 5-HT1A Receptor Agonist Relieves Depression and Depression-Induced Hypoalgesia  

PubMed Central

Previous studies have shown that depressed patients as well as animal models of depression exhibit decreased sensitivity to evoked pain stimuli, and serotonin is indicated to be involved in depression-induced hypoalgesia. The purpose of this study was to investigate the potential role of 5-HT1A receptor in the depression-induced hypoalgesia. Acute or chronic administration of 5-HT1A receptor agonist, 8-OH-DPAT, was performed in olfactory bulbectomy (OB) and sham-operated rats. The depression-like behavior and pain thresholds were measured using open-field test and radiant heat thermal pain test, respectively. We found that acute administration of 8-OH-DPAT increased locomotor activity and pain thresholds in the sham rats but had no effect on the OB rats. In contrast, chronic administration of 8-OH-DPAT reduced locomotor activity and pain thresholds and restored them to normal level. Increased pain thresholds were also observed in the sham rats after the chronic administration. These results demonstrated that chronic administration of 8-OH-DPAT reversed the depression-induced decrease in pain sensitivity in rats, suggesting that 5-HT1A receptor may play a role in the depression-associated hypoalgesia. PMID:24592167

Qi, Wei-Jing

2014-01-01

292

Dystroglycan matrix receptor function in cardiac myocytes is important for limiting activity-induced myocardial damage  

PubMed Central

Rationale Genetic mutations in a number of putative glycosyltransferases lead to the loss of glycosylation of dystroglycan and loss of its laminin binding activity in genetic forms of human muscular dystrophy. Human patients and glycosylation defective myd mice develop cardiomyopathy with loss of dystroglycan matrix receptor function in both striated and smooth muscle. Objective To determine the functional role of dystroglycan in cardiac muscle and smooth muscle in the development of cardiomyopathy in muscular dystrophies. Methods and results Using Cre/lox mediated gene targeting, we show here that loss of dystroglycan function in ventricular cardiac myocytes is sufficient to induce a progressive cardiomyopathy in mice characterized by focal cardiac fibrosis, increase in cardiac mass, and dilatation ultimately leading to heart failure. In contrast, disruption of dystroglycan in smooth muscle is not sufficient to induce cardiomyopathy. The specific loss of dystroglycan function in cardiac myocytes causes the accumulation of large, clustered patches of myocytes with membrane damage, which increase in number in response to exercise induced cardiac stress, while exercised mice with normal dystroglycan expression accumulate membrane damage limited to individual myocytes. Conclusions Our findings suggest dystroglycan function as an extracellular matrix receptor in cardiac myocytes plays a primary role in limiting myocardial damage from spreading to neighboring cardiac myocytes, and loss of dystroglycan matrix receptor function in cardiac muscle cells is likely important in the development of cardiomyopathy in glycosylation-deficient muscular dystrophies. PMID:19797173

Michele, Daniel E.; Kabaeva, Zhyldyz; Davis, Sarah L.; Weiss, Robert M.; Campbell, Kevin P.

2009-01-01

293

LPS-induced dental pulp inflammation increases expression of ionotropic purinergic receptors in rat trigeminal ganglion.  

PubMed

Severe toothache can be caused by dental pulp inflammation. The ionotropic purinergic receptor family (P2X) is reported to mediate nociception in primary afferent neurons. This study aims to investigate the involvement of P2X receptors in the sensitization of the trigeminal ganglion (TG) caused by dental pulp inflammation. Lipopolysaccharides were unilaterally applied to the pulp of the upper molar of the rat to induce dental pulp inflammation. Increased expression of c-fos, a marker of neuronal activity, was induced in V1-V2 division, indicating the activation of TG neurons. The expressions of P2X2, P2X3, and P2X5 were also increased in the V1-V2 division of TG, primarily in small-sized and medium-sized neurons. Markers of glutamatergic afferents, VGluT1, and GABAergic afferents, GAD67, were induced by lipopolysaccharides and coexpressed with P2X in small-sized TG neurons. The present findings suggest that the P2X2, P2X3, and P2X5 receptors are upregulated as part of the sensitization produced by dental pulp inflammation. PMID:25055139

Chen, Yangxi; Zhang, Li; Yang, Jingwen; Zhang, Lu; Chen, Zhi

2014-09-10

294

Implication of mGlu5 receptor in the enhancement of morphine-induced hyperlocomotion under chronic treatment with zolpidem.  

PubMed

Long-term exposure to zolpidem induces drug dependence, and it is well known that the balance between the GABAergic and glutamatergic systems plays a critical role in maintaining the neuronal network. In the present study, we investigated the interaction between GABAA receptor ?1 subunit and mGlu5 receptor in the limbic forebrain including the N.Acc. after treatment with zolpidem for 7 days. mGlu5 receptor protein levels were significantly increased after treatment with zolpidem for 7 days, and this change was accompanied by the up-regulation of phospholipase C?1 and calcium/calmodulin-dependent protein kinase II?, which are downstream of mGlu5 receptor in the limbic forebrain. To confirm that mGlu5 receptor is directly involved in dopamine-related behavior in mice following chronic treatment with zolpidem, we measured morphine-induced hyperlocomotion after chronic treatment with zolpidem in the presence or absence of an mGlu5 receptor antagonist. Although chronic treatment with zolpidem significantly enhanced morphine-induced hyperlocomotion, this enhancement of morphine-induced hyperlocomotion was suppressed by treating it with the mGlu5 receptor antagonist MPEP. These results suggest that chronic treatment with zolpidem caused neural plasticity in response to activation of the mesolimbic dopaminergic system accompanied by an increase in mGlu5 receptor. PMID:24930812

Shibasaki, Masahiro; Ishii, Kazunori; Masukawa, Daiki; Ando, Koji; Ikekubo, Yuiko; Ishikawa, Yutori; Shibasaki, Yumiko; Mori, Tomohisa; Suzuki, Tsutomu

2014-09-01

295

Ischemia- and agonist-induced changes in. alpha. - and. beta. -adrenergic receptor traffic in guinea pig hearts  

SciTech Connect

The authors have used radioligand binding techniques and subcellular fraction to assess whether changes in expression of myocardial {alpha}{sub 1}- and {beta}-adrenergic receptors are mediated by a redistribution of receptors between various membrane fractions. Three fractions were prepared from the left ventricles of guinea pigs that underwent either 1 h of ischemia or injection of epinephrine a crude membrane, a purified sarcolemma, and a light vesicle fraction. In control animals {alpha}{sub 1}-adrenergic receptors (({sup 3}H)prazosin binding) in light vesicles was only 25% of the total {alpha}{sub 1}-receptor density found in sarcolemmal and light vesicle fractions as compared with 50% for {beta}-adrenergic receptors (({sup 125}I)iodocyanopindolol binding sites). Although ischemia was associated with a 53% decrease in the number of light vesicle {beta}-adrenergic receptors and a 42% increase in the number of sarcolemma {beta}-receptors there was no change in the number of light vesicle {alpha}{sub 1}-receptors, even though the number of sarcolemmal {alpha}{sub 1}-receptors increased 34%. Epinephrine treatment promoted internalization of {beta}-adrenergic receptors. These results indicate that {alpha}{sub 1} and {beta}{sub 1}-adrenergic receptors may undergo a different cellular itinerary in guinea pig myocardium. Agonist and ischemia-induced changes in surface {beta}-receptors, but not {alpha}{sub 1}-receptors, appear to result from entry and exit of receptors from an intracellular pool that can be isolated in a light vesicle fraction. Changes in expression of {alpha}{sub 1}-adrenergic receptors may represent changes in the properties of receptors found in the sarcolemma or in a membrane fraction other than the light vesicle fraction that they have isolated.

Maisel, A.S.; Motulsky, H.J.; Ziegler, M.G.; Insel, P.A. (Univ. of California, La Jolla (USA))

1987-11-01

296

UV-induced signal transduction in epidermal cells: from surface receptors to protein kinase C: a mathematical model  

NASA Astrophysics Data System (ADS)

In the paper the mathematical model of UV-induced PKC activation is presented. Phosphorylation of membrane receptors, activation of phospholipases and phospholipids turnover, diacylglycerol, inositol trisphosphate and arachidonic acid production, calcium releasing are taken into account.

Stolnitz, Mikhail M.; Peshkova, Anna Y.

2002-05-01

297

Orphan nuclear receptor Nur77 mediates fasting-induced hepatic fibroblast growth factor 21 expression.  

PubMed

The fasting-induced hepatic hormone, fibroblast growth factor 21 (FGF21), is a potential candidate for the treatment of metabolic syndromes. Although peroxisome proliferator-activated receptor (PPAR)? is known to play a major role in the induction of hepatic FGF21 expression, other fasting-induced transcription factors that induce FGF21 expression have not yet been fully studied. In the present study, we investigated whether the fasting-induced activation of the orphan nuclear receptor Nur77 increases hepatic FGF21 expression. We found that fasting induced hepatic Nur77 and FGF21 expression. Glucagon and forskolin increased Nur77 and FGF21 expression in vivo and in vitro, respectively, and adenovirus-mediated overexpression of Nur77 (Ad-Nur77) increased FGF21 expression in vitro and in vivo. Moreover, knockdown of endogenous Nur77 expression by siRNA-Nur77 abolished the effect of forskolin on FGF21 expression. The results of ChIP assays, EMSA, and mutagenesis analysis showed that Nur77 bound to the putative NBRE of the FGF21 promoter in cultured hepatocytes and fasting induced Nur77 binding to the FGF21 promoter in vivo. Knockdown of PPAR? partially inhibited forskolin-induced FGF21 expression, suggesting PPAR? involvement in glucagon-stimulated FGF21 expression. In addition, double knockdown of PPAR? and Nur77 further diminished FGF21 expression in cultured hepatocytes. In conclusion, this study shows that Nur77 mediates fasting-induced hepatic FGF21 expression, and suggests an alternative mechanism via which hepatic FGF21 transcription is mediated under fasting conditions. PMID:24885573

Min, Ae-Kyung; Bae, Kwi-Hyun; Jung, Yun-A; Choi, Yeon-Kyung; Kim, Mi-Jin; Kim, Ji-Hyun; Jeon, Jae-Han; Kim, Jung-Guk; Lee, In-Kyu; Park, Keun-Gyu

2014-08-01

298

Dehydroepiandrosterone-induces miR-21 transcription in HepG2 cells through estrogen receptor ? and androgen receptor.  

PubMed

Although oncomiR miR-21 is highly expressed in liver and overexpressed in hepatocellular carcinoma (HCC), its regulation is uncharacterized. We examined the effect of physiologically relevant nanomolar concentrations of dehydroepiandrosterone (DHEA) and DHEA sulfate (DHEA-S) on miR-21 expression in HepG2 human hepatoma cells. 10nM DHEA and DHEA-S increase pri-miR-21 transcription in HepG2 cells. Dietary DHEA increased miR-21 in vivo in mouse liver. siRNA and inhibitor studies suggest that DHEA-S requires desulfation for activity and that DHEA-induced pri-miR-21 transcription involves metabolism to androgen and estrogen receptor (AR and ER) ligands. Activation of ER? and AR by DHEA metabolites androst-5-ene-3,17-dione (ADIONE), androst-5-ene-3?,17?-diol (ADIOL), dihydrotestosterone (DHT), and 5?-androstane-3?,17?-diol (3?-Adiol) increased miR-21 transcription. DHEA-induced miR-21 increased cell proliferation and decreased Pdcd4 protein, a bona fide miR-21. Estradiol (E2) inhibited miR-21 expression via ER?. DHEA increased ER? and AR recruitment to the miR-21 promoter within the VMP1/TMEM49 gene, with possible significance in hepatocellular carcinoma. PMID:24845419

Teng, Yun; Litchfield, Lacey M; Ivanova, Margarita M; Prough, Russell A; Clark, Barbara J; Klinge, Carolyn M

2014-07-01

299

Cranberries (Oxycoccus quadripetalus) inhibit adipogenesis and lipogenesis in 3T3-L1 cells.  

PubMed

Cranberries (Oxycoccus quadripetalus) are a valuable source of bioactive substances with high antioxidant potential and well documented beneficial health properties. In the present study, the activity of cranberries, in terms of the inhibiting effects of adipogenesis, was investigated using the 3T3-L1 cell line. The obtained results showed that cranberries reduced proliferation and viability of 3T3-L1 preadipocytes in a dose-dependent manner. Treatment with cranberries decreased the number of adipocytes and reduced lipid accumulation in maturing 3T3-L1 preadipocytes, demonstrating an inhibitory effect on lipogenesis. Moreover, it was found that cranberries directly induced lipolysis in adipocytes and down-regulated the expression of major transcription factors of the adipogenesis pathway, such as PPAR?, C/EBP? and SREBP1. These findings indicate that cranberries are capable of suppressing adipogenesis and therefore they seem to be natural bioactive factors effective in adipose tissue mass modulation. PMID:24262553

Kowalska, Katarzyna; Olejnik, Anna; Rychlik, Joanna; Grajek, W?odzimierz

2014-04-01

300

Tramadol reduces the 5-HTP-induced head–twitch response in mice via the activation of ? and ? opioid receptors  

Microsoft Academic Search

Tramadol, an atypical opioid analgesic, stimulates both opiatergic and serotonergic systems. Here we have investigated the effect of tramadol in mice on 5-hydroxyptrytophan (5-HTP)-induced head twitch response (HTR), which is an animal model for the activation of the CNS 5-HT2A receptors in mice. Tramadol attenuated 5-HTP-induced HTR in a dose-dependent manner as morphine. Furthermore, the nonselective opioid receptor antagonists, naloxone

Hong-Lei Sun; Ji-Wang Zheng; Keng Wang; Rui-Ke Liu; Jian-Hui Liang

2003-01-01

301

Thyroid hormone regulation of gene expression in primary cerebrocortical cells: role of thyroid hormone receptor subtypes and interactions with retinoic acid and glucocorticoids.  

PubMed

The effects of thyroid hormone on brain development and function are largely mediated by the binding of 3,5,3'-triiodo-L-thyronine (T3) to its nuclear receptors (TR) to regulate positively or negatively gene expression. We have analyzed by quantitative polymerase chain reaction the effect of T3 on primary cultured cells from the embryonic mouse cerebral cortex, on the expression of Hr, Klf9, Shh, Dio3, Aldh1a1, and Aldh1a3. In particular we focused on T3 receptor specificity, and on the crosstalk between T3, retinoic acid and dexamethasone. To check for receptor subtype specificity we used cerebrocortical cells derived from wild type mice and from mice deficient in thyroid hormone receptor subtypes. Receptor subtype specificity was found for Dio3 and Aldh1a1, which were induced by T3 only in cells expressing the T3 receptor alpha 1 subtype. Interactions of T3 with retinoic acid signaling through the control of retinoic acid metabolism are likely to be important during development. T3 had opposing influences on retinoic acid synthesizing enzymes, increasing the expression of Aldh1a1, and decreasing Aldh1a3, while increasing the retinoic acid degrading enzyme Cyp26b1. Dexamethasone increased Klf9 and Aldh1a1 expression. The effects of T3 and dexamethasone on Aldh1a1 were highly synergistic, with mRNA increments of up to 20 fold. The results provide new data on thyroid hormone regulation of gene expression and underscore the importance of thyroid hormone interactions with retinoic acid and glucocorticoids during neural development. PMID:24618783

Gil-Ibáńez, Pilar; Bernal, Juan; Morte, Beatriz

2014-01-01

302

Thyroid Hormone Regulation of Gene Expression in Primary Cerebrocortical Cells: Role of Thyroid Hormone Receptor Subtypes and Interactions with Retinoic Acid and Glucocorticoids  

PubMed Central

The effects of thyroid hormone on brain development and function are largely mediated by the binding of 3,5,3?-triiodo-L-thyronine (T3) to its nuclear receptors (TR) to regulate positively or negatively gene expression. We have analyzed by quantitative polymerase chain reaction the effect of T3 on primary cultured cells from the embryonic mouse cerebral cortex, on the expression of Hr, Klf9, Shh, Dio3, Aldh1a1, and Aldh1a3. In particular we focused on T3 receptor specificity, and on the crosstalk between T3, retinoic acid and dexamethasone. To check for receptor subtype specificity we used cerebrocortical cells derived from wild type mice and from mice deficient in thyroid hormone receptor subtypes. Receptor subtype specificity was found for Dio3 and Aldh1a1, which were induced by T3 only in cells expressing the T3 receptor alpha 1 subtype. Interactions of T3 with retinoic acid signaling through the control of retinoic acid metabolism are likely to be important during development. T3 had opposing influences on retinoic acid synthesizing enzymes, increasing the expression of Aldh1a1, and decreasing Aldh1a3, while increasing the retinoic acid degrading enzyme Cyp26b1. Dexamethasone increased Klf9 and Aldh1a1 expression. The effects of T3 and dexamethasone on Aldh1a1 were highly synergistic, with mRNA increments of up to 20 fold. The results provide new data on thyroid hormone regulation of gene expression and underscore the importance of thyroid hormone interactions with retinoic acid and glucocorticoids during neural development. PMID:24618783

Gil-Ibanez, Pilar; Bernal, Juan; Morte, Beatriz

2014-01-01

303

Mechanism of synapse redox stress in Okadaic acid (ICV) induced memory impairment: Role of NMDA receptor.  

PubMed

The N-methyl-D-aspartate (NMDA) receptor is a subtype of ionotropic glutamate receptor that is involved in synaptic mechanisms of learning and memory, and mediates excitotoxic neuronal injury. In this study, we tested the hypothesis that NMDA receptor subunit gene expression is altered in cortex and hippocampus of OKA induced memory impairment. Therefore in the present study, we checked the effect of OKA (ICV) on NMDA receptor regulation and synapse function. The memory function anomalies and synaptosomal calcium ion (Ca(2+)) level were increased in OKA treated rats brain; which was further protected by MK801 (0.05mg/kg. i.p) treatment daily for 13days. To elucidate the involvement of NMDA receptor, we estimated NR1, NR2A and NR2B (subunits) expression in rat brain. Results showed that expression of NR1 and NR2B were significantly increased, but expression of NR2A had no significant change in OKA treated rat brain. We also observed decrease in synapsin-1 mRNA and protein expression which indicates synapse dysfunction. In addition, we detected an increase in MDA and nitrite levels and a decrease in GSH level in synapse preparation which indicates synapse altered redox stress. Moreover, neuronal loss was also confirmed by nissl staining in periventricular cortex and hippocampus. Altered level of oxidative stress markers along with neuronal loss confirmed neurotoxicity. Further, MK801 treatment restored the level of NR1, NR2B and synapsin-1 expression, and protected from neuronal loss and synapse redox stress. In conclusion, Okadaic acid (OKA) induced expression of NR1 and NR2B deteriorates synapse function in rat brain which was confirmed by the neuroprotective effect of MK801. PMID:24984170

Kamat, Pradip K; Rai, Shivika; Swarnkar, Supriya; Shukla, Rakesh; Nath, Chandishwar

2014-10-01

304

5-Hydroxytryptamine Type 3 Receptor Modulates Opioid-induced Hyperalgesia and Tolerance in Mice  

PubMed Central

Background Opioid-induced hyperalgesia (OIH) and tolerance are challenging maladaptations associated with opioids in managing pain. Recent genetic studies and the existing literature suggest the 5-hydroxy tryptamine type 3 (5-HT3) receptor participates in these phenomena. The location of the relevant receptor populations and the interactions between the 5-HT3 system and other systems controlling OIH and tolerance have not been explored, however. We hypothesized that 5-HT3 receptors modulate OIH and tolerance, and that this modulation involves the control of expression of multiple neurotransmitter and receptor systems. Methods C57BL/6 mice were exposed to a standardized 4-day morphine administration protocol. The 5-HT3 antagonist ondansetron was administered either during or after the conclusion of morphine administration. Mechanical testing was used to quantify OIH, and thermal tail flick responses were used to measure morphine tolerance. In other experiments spinal cord and dorsal root ganglion tissues were harvested for analysis of messenger RNA levels by real-time polymerase chain reaction or immunochemistry analysis. Results The results showed 1) Systemic or intrathecal injection of ondansetron significantly prevented and reversed OIH, but not local intraplantar injection. 2) Systemic or intrathecal injection of ondansetron prevented and reversed tolerance, and 3) Ondansetron blocked morphine induced increases of multiple genes -relevant to OIH and tolerance in dorsal root ganglion and spinal cord. Conclusions Morphine acts via a 5-HT3 dependent mechanism to support multiple maladaptations to the chronic administration of morphine. Furthermore, the use of 5-HT3 receptor antagonists may provide a new avenue to prevent or reverse OIH and tolerance associated with chronic opioid use. PMID:21368652

Liang, De-Yong; Li, XiangQi; Clark, J. David

2011-01-01

305

?-Adrenergic receptor antagonism prevents anxiety-like behavior and microglial reactivity induced by repeated social defeat.  

PubMed

Psychosocial stress is associated with altered immune function and development of psychological disorders including anxiety and depression. Here we show that repeated social defeat in mice increased c-Fos staining in brain regions associated with fear and threat appraisal and promoted anxiety-like behavior in a ?-adrenergic receptor-dependent manner. Repeated social defeat also significantly increased the number of CD11b(+)/CD45(high)/Ly6C(high) macrophages that trafficked to the brain. In addition, several inflammatory markers were increased on the surface of microglia (CD14, CD86, and TLR4) and macrophages (CD14 and CD86) after social defeat. Repeated social defeat also increased the presence of deramified microglia in the medial amygdala, prefrontal cortex, and hippocampus. Moreover, mRNA analysis of microglia indicated that repeated social defeat increased levels of interleukin (IL)-1? and reduced levels of glucocorticoid responsive genes [glucocorticoid-induced leucine zipper (GILZ) and FK506 binding protein-51 (FKBP51)]. The stress-dependent changes in microglia and macrophages were prevented by propranolol, a ?-adrenergic receptor antagonist. Microglia isolated from socially defeated mice and cultured ex vivo produced markedly higher levels of IL-6, tumor necrosis factor-?, and monocyte chemoattractant protein-1 after stimulation with lipopolysaccharide compared with microglia from control mice. Last, repeated social defeat increased c-Fos activation in IL-1 receptor type-1-deficient mice, but did not promote anxiety-like behavior or microglia activation in the absence of functional IL-1 receptor type-1. These findings indicate that repeated social defeat-induced anxiety-like behavior and enhanced reactivity of microglia was dependent on activation of ?-adrenergic and IL-1 receptors. PMID:21525267

Wohleb, Eric S; Hanke, Mark L; Corona, Angela W; Powell, Nicole D; Stiner, La'Tonia M; Bailey, Michael T; Nelson, Randy J; Godbout, Jonathan P; Sheridan, John F

2011-04-27

306

Cytokines and neutrophils as important mediators of platelet-activating factor-induced kinin B1 receptor expression  

PubMed Central

PAF injection into the rat paw is accompanied by the concomitant activation of NF-?B and neutrophil influx, which appears to be relevant to the up-regulation of kinin B1 receptors. Herein, we analyse the role of TNF-? and IL-1? production for PAF-induced B1 receptor upregulation in the rat paw. Additionally, we evaluate how cytokine production and neutrophil migration fit into the temporal sequence of events leading to PAF-induced B1 receptor upregulation. In our experiments, treatment with PAF resulted in a marked increase of B1 receptor-mediated paw oedema and in situ production of TNF-? at 1?h and IL-1? at 3 and 6?h later. B1 receptor-mediated paw oedema was significantly inhibited by anti-TNF-? antibody and by interleukin-1 receptor antagonist (IRA). TNF-? was necessary for the local PAF-induced IL-1? production. NF-?B blocker PDTC prevented the production of both TNF-? and IL-1?, indicating that cytokine production is NF-?B dependent. Depletion of neutrophils with an anti-PMN antibody prevented IL-1?, but not TNF-?, production. Although both TNF-? and IL-1? are relevant to functional B1 receptor upregulation, PAF-induced increase in B1 receptor mRNA was markedly suppressed by anti-TNF-? and, to a lesser extent, by IRA. B1 receptor mRNA expression was also prevented by the anti-PMN antibody. In conclusion, the activation of the TNF-?/neutrophil axis by PAF seems to be sufficient for B1 receptor mRNA production. However, the TNF-?/neutrophil axis is also necessary for IL-1? production. These two processes might lead to the appearance of functional kinin B1 upregulation receptors in vivo after PAF treatment. PMID:16025141

Fernandes, Elizabeth S; Passos, Giselle F; Campos, Maria M; de Souza, Gloria E P; Fittipaldi, Juliana F; Pesquero, Jorge L; Teixeira, Mauro M; Calixto, Joao B

2005-01-01

307

Amygdala opioid receptors mediate the electroacupuncture-induced deterioration of sleep disruptions in epilepsy rats  

PubMed Central

Background Clinical and experimental evidence demonstrates that sleep and epilepsy reciprocally affect each other. Previous studies indicated that epilepsy alters sleep homeostasis; in contrast, sleep disturbance deteriorates epilepsy. If a therapy possesses both epilepsy suppression and sleep improvement, it would be the priority choice for seizure control. Effects of acupuncture of Feng-Chi (GB20) acupoints on epilepsy suppression and insomnia treatment have been documented in the ancient Chinese literature, Lingshu Jing (Classic of the Miraculous Pivot). Therefore, this study was designed to investigate the effect of electroacupuncture (EA) stimulation of bilateral Feng-Chi acupoints on sleep disruptions in rats with focal epilepsy. Results Our result indicates that administration of pilocarpine into the left central nucleus of amygdala (CeA) induced focal epilepsy and decreased both rapid eye movement (REM) sleep and non-REM (NREM) sleep. High-frequency (100 Hz) EA stimulation of bilateral Feng-Chi acupoints, in which a 30-min EA stimulation was performed before the dark period of the light:dark cycle in three consecutive days, further deteriorated pilocarpine-induced sleep disruptions. The EA-induced exacerbation of sleep disruption was blocked by microinjection of naloxone, ?- (naloxonazine), ?- (nor-binaltorphimine) or ?-receptor antagonists (natrindole) into the CeA, suggesting the involvement of amygdaloid opioid receptors. Conclusion The present study suggests that high-frequency (100 Hz) EA stimulation of bilateral Feng-Chi acupoints exhibits no benefit in improving pilocarpine-induced sleep disruptions; in contrast, EA further deteriorated sleep disturbances. Opioid receptors in the CeA mediated EA-induced exacerbation of sleep disruptions in epileptic rats. PMID:24215575

2013-01-01

308

Insulin receptor substrates 1 and 2 but not Shc can activate the insulin receptor independent of insulin and induce proliferation in CHO-IR cells  

SciTech Connect

Ligand-activated insulin receptor (IR) attracts and phosphorylates various substrates such as insulin receptor substrates 1-4 (IRS) and Shc. To investigate how binding affinity for substrate affects signalling we generated chimeric receptors with the {beta}-chain of the insulin receptor containing NPXY motives with different affinities for receptor substrates. We found that the extent of receptor tyrosine phosphorylation positively correlates with binding affinity towards IRS1/2 but not towards Shc. Moreover, overexpression of IRS1 or IRS2 but not of Shc increased IR tyrosine phosphorylation in a dose-dependent manner, also independent of insulin. Molecular truncations of IRS1 revealed that neither the isolated PH and PTB domains nor the C-terminus with the tyrosine phosphorylation sites alone are sufficient for substrate-dependent receptor activation. Overexpression of IRS1 and IRS2 impaired insulin-induced internalization of the IR in a dose-dependent manner suggesting that IRS proteins prevent endosome-associated receptor dephosphorylation/inactivation. IRS1 and IRS2 could therefore target the activated IR to different cellular compartments. Overexpression of IRS1 and IRS2 inhibited insulin-stimulated activation of the MAP kinases Erk1/2 while it increased/induced activation of Akt/PKB. Finally, overexpression of IRS1 and IRS2 but not of Shc induced DNA synthesis in starved CHO-IR cells independent of exogenous growth factors. Our results demonstrate that variations in cellular IRS1 and IRS2 concentration affect insulin signalling both upstream and downstream and that IRS proteins could play instructive rather than just permissive roles in signal transmission.

Niessen, Markus [Department of Endocrinology and Diabetes, University Hospital Zurich, Ramistrasse 100, 8091 Zurich (Switzerland) and Competence Center for Systems Physiology and Metabolic Diseases, ETH Honggerberg, Schafmattstr. 18, 8093 Zurich (Switzerland)]. E-mail: markus.niessen@usz.ch; Jaschinski, Frank [Department of Endocrinology and Diabetes, University Hospital Zurich, Ramistrasse 100, 8091 Zurich (Switzerland); Item, Flurin [Department of Endocrinology and Diabetes, University Hospital Zurich, Ramistrasse 100, 8091 Zurich (Switzerland); Institute of Human Movement Sciences and Sport, ETH Zurich, Winterthurerstrasse 190, 8057 Zurich (Switzerland); McNamara, Morgan P. [Department of Endocrinology and Diabetes, University Hospital Zurich, Ramistrasse 100, 8091 Zurich (Switzerland); Spinas, Giatgen A. [Department of Endocrinology and Diabetes, University Hospital Zurich, Ramistrasse 100, 8091 Zurich (Switzerland); Competence Center for Systems Physiology and Metabolic Diseases, ETH Honggerberg, Schafmattstr. 18, 8093 Zurich (Switzerland); Trueb, Thomas [Zentrale Dienste der Universitaet, Ausruestung und Logistik, Y10 G 22, Winterthurerstrasse 190, 8057 Zurich (Switzerland)

2007-02-15

309

Vasopressin rapidly stimulates protein kinase C in quiescent Swiss 3T3 cells.  

PubMed

Addition of vasopressin to quiescent cultures of Swiss 3T3 cells caused a rapid increase in the phosphorylation of an acidic molecular weight 80,000 cellular protein (termed 80K). The effect was concentration- and time-dependent; enhancement in 80K phosphorylation could be detected as early as 30 sec after the addition of the hormone. Recently, a rapid increase in the phosphorylation of an 80K cellular protein following treatment with phorbol esters or diacylglycerol has been shown to reflect the activation of protein kinase C in intact Swiss 3T3 cells. Here we show that the 80K phosphoproteins generated in response to vasopressin and phorbol 12,13-dibutyrate (PBt2) were identical as judged by one- and two-dimensional polyacrylamide gel electrophoresis (PAGE) and peptide mapping following partial proteolysis with Staphylococcus aureus V8 protease. In addition, prolonged pretreatment of 3T3 cells with PBt2 which leads to the disappearance of protein kinase C activity blocked the ability of vasopressin to stimulate the phosphorylation of 80K. The effect of vasopressin on 80K phosphorylation and mitogenesis was selectively blocked by the vasopressin antagonist (Pmp1-O-Me-Tyr2-Arg8) vasopressin suggesting that these responses are mediated by its specific receptor in these cells. The removal of vasopressin leads to dephosphorylation (within minutes) of the 80K phosphoprotein. We conclude that vasopressin rapidly stimulates protein kinase C activity in intact 3T3 cells. PMID:2944907

Rodriguez-Pena, A; Rozengurt, E

1986-10-01

310

Spinal 5-HT7 receptors and protein kinase A constrain intermittent hypoxia-induced phrenic long-term facilitation.  

PubMed

Phrenic long-term facilitation (pLTF) is a form of serotonin-dependent respiratory plasticity induced by acute intermittent hypoxia (AIH). pLTF requires spinal Gq protein-coupled serotonin-2 receptor (5-HT2) activation, new synthesis of brain-derived neurotrophic factor (BDNF) and activation of its high-affinity receptor, TrkB. Intrathecal injections of selective agonists for Gs protein-coupled receptors (adenosine 2A and serotonin-7; 5-HT7) also induce long-lasting phrenic motor facilitation via TrkB "trans-activation." Since serotonin released near phrenic motor neurons may activate multiple serotonin receptor subtypes, we tested the hypothesis that 5-HT7 receptor activation contributes to AIH-induced pLTF. A selective 5-HT7 receptor antagonist (SB-269970, 5mM, 12 ?l) was administered intrathecally at C4 to anesthetized, vagotomized and ventilated rats prior to AIH (3, 5-min episodes, 11% O2). Contrary to predictions, pLTF was greater in SB-269970 treated versus control rats (80 ± 11% versus 45 ± 6% 60 min post-AIH; p<0.05). Hypoglossal LTF was unaffected by spinal 5-HT7 receptor inhibition, suggesting that drug effects were localized to the spinal cord. Since 5-HT7 receptors are coupled to protein kinase A (PKA), we tested the hypothesis that PKA inhibits AIH-induced pLTF. Similar to 5-HT7 receptor inhibition, spinal PKA inhibition (KT-5720, 100 ?M, 15 ?l) enhanced pLTF (99 ± 15% 60 min post-AIH; p<0.05). Conversely, PKA activation (8-br-cAMP, 100 ?M, 15 ?l) blunted pLTF versus control rats (16 ± 5% versus 45 ± 6% 60 min post-AIH; p<0.05). These findings suggest a novel mechanism whereby spinal Gs protein-coupled 5-HT7 receptors constrain AIH-induced pLTF via PKA activity. PMID:23850591

Hoffman, M S; Mitchell, G S

2013-10-10

311

Effect of Coptidis Rhizoma extracts in a water-based solution on insulin resistance in 3T3-L1 adipocytes.  

PubMed

The present study was designed to investigate effects and molecular mechanisms of Coptidis Rhizoma extracts (CRE) on the improvement of insulin resistance induced by tumor necrosis factor-? (TNF-?) in adipocytes. We examined whether CRE administration could directly influence the insulin resistance in 3T3-L1 adipocytes. Potential roles of CRE in glucose consumption, mRNA expression of peroxisome proliferators activated receptor (PPAR-?), expression of insulin receptor substrate-1 (IRS-1) protein, and phosphorylation of IRS-1 Ser307 were also investigated in the present study. Our data demonstrated that TNF-? significantly reduced levels of glucose consumption and IRS-1 protein expression, while TNF-? increased the phosphorylation of IRS-1 Ser307 in adipocytes 24 h after the challenge, suggesting that TNF-? induced a condition with the occurrence of insulin resistance. Those alterations induced by TNF-? were prevented and the mRNA expression of PPAR-? was up-regulated by the administration of CRE. Thus, our results indicate that CRE can be used to prevent from the TNF-?-induced insulin resistance through PPAR-? pathways. PMID:25355439

Yuan, Yi; Wang, Xuhui; Lu, Xiaojiong; Marunaka, Yoshinori; Wang, Xiangdong

2014-01-01

312

An Unliganded Thyroid Hormone ? Receptor Activates the Cyclin D1/Cyclin-Dependent Kinase/Retinoblastoma/E2F Pathway and Induces Pituitary Tumorigenesis  

PubMed Central

Thyroid-stimulating hormone (TSH)-secreting tumors (TSH-omas) are pituitary tumors that constitutively secrete TSH. The molecular genetics underlying this abnormality are not known. We discovered that a knockin mouse harboring a mutated thyroid hormone receptor (TR) ? (PV; TR?PV/PV mouse) spontaneously developed TSH-omas. TR?PV/PV mice lost the negative feedback regulation with highly elevated TSH levels associated with increased thyroid hormone levels (3,3?,5-triiodo-l-thyronine [T3]). Remarkably, we found that mice deficient in all TRs (TR?1?/? TR??/?) had similarly increased T3 and TSH levels, but no discernible TSH-omas, indicating that the dysregulation of the pituitary-thyroid axis alone is not sufficient to induce TSH-omas. Comparison of gene expression profiles by cDNA microarrays identified overexpression of cyclin D1 mRNA in TR?PV/PV but not in TR?1?/? TR??/? mice. Overexpression of cyclin D1 protein led to activation of the cyclin D1/cyclin-dependent kinase/retinoblastoma protein/E2F pathway only in TR?PV/PV mice. The liganded TR? repressed cyclin D1 expression via tethering to the cyclin D1 promoter through binding to the cyclic AMP response element-binding protein. That repression effect was lost in mutant PV, thereby resulting in constitutive activation of cyclin D1 in TR?PV/PV mice. The present study revealed a novel molecular mechanism by which an unliganded TR? mutant acts to contribute to pituitary tumorigenesis in vivo and provided mechanistic insights into the understanding of pathogenesis of TSH-omas in patients. PMID:15601836

Furumoto, Hiroko; Ying, Hao; Chandramouli, G. V. R.; Zhao, Li; Walker, Robert L.; Meltzer, Paul S.; Willingham, Mark C.; Cheng, Sheue-Yann

2005-01-01

313

Proteomic analysis of rosiglitazone and guggulsterone treated 3T3-L1 preadipocytes.  

PubMed

Adipogenesis is the differentiation of preadipocytes to adipocytes which is marked by the accumulation of lipid droplets. Adipogenic differentiation of 3T3-L1 cells is achieved by exposing the cells to Insulin, Dexamethasone and IBMX for 5-7 days. Thiazolidinedione drugs, like rosiglitazone are potent insulin sensitizing agents and have been shown to enhance lipid droplet formation in 3T3-L1 cells, a model cell line for preadipocyte differentiation. Guggulsterone is a natural drug extracted from the gum resin of tree Commiphora mukul. Guggulsterone has been shown to inhibit adipogenesis and induce apoptosis in 3T3-L1 cells. In this study we treated the 3T3-L1 preadipocytes with rosiglitazone and guggulsterone and assessed the protein expression profile using 2D gel electrophoresis-based proteomics to find out differential target proteins of these drugs. The proteins that were identified upon rosiglitazone treatment generally regulate cell proliferation and/or exhibit anti-inflammatory effect which strengthens its differentiation-inducing property. Guggulsterone treatment resulted in the identification of the apoptosis-inducing proteins to be up regulated which rightly is in agreement with the apoptosis-inducing property of guggulsterone in 3T3-L1 cells. Some of the proteins identified in our proteomic screen such as Galectin1, AnnexinA2 & TCTP were further confirmed by Real Time qPCR. Thus, the present study provides a better outlook of proteins being differentially regulated/expressed upon treatment with rosiglitazone and guggulsterone. The detailed study of the differentially expressed proteins identified in this proteomic screen may further provide the better molecular insight into the mode of action of these anti-diabetic drugs rosiglitazone and guggulsterone. PMID:23275126

Pal, Pooja; Kanaujiya, Jitendra K; Lochab, Savita; Tripathi, Shashi B; Sanyal, Sabyasachi; Behre, Gerhard; Trivedi, Arun K

2013-04-01

314

Role of neurokinin-1 and dopamine receptors on the striatal methamphetamine-induced proliferation of new cells in mice.  

PubMed

A neurotoxic dose of methamphetamine (METH) induces the loss of some striatal neurons. Interestingly, the METH-induced apoptosis in the striatum is immediately followed by the generation of new cells (cytogenesis). In the present study, we investigated the role of the neurokinin-1, dopamine D1 and D2 receptors on the METH-induced cytogenesis. To that end, male mice were given a single injection (30 mg/kg, ip) or a binge of METH (10mg/kg, 4× at two-hour intervals, ip). BrdU (100mg/kg, ip) was given 36 h after the last injection of METH. Newly generated cells were detected by immunohistochemistry and cell counts were performed using unbiased computerized stereology. Either single or binge exposure to METH resulted in the generation of new cells. The single optimized dose was used for subsequent mechanistic studies. Pretreatment with the dopamine D1 receptor antagonist SCH23390 (0.1mg/kg, ip) 30 min prior to METH abrogated the METH-induced striatal cytogenesis. Pretreatment with the dopamine D2 receptor antagonist raclopride (1mg/kg, ip) failed to affect this phenomenon. Finally, pretreatment with the neurokinin-1 receptor antagonist WIN 51,708 (5mg/kg, ip) 30 min prior to METH abrogated the METH-induced cytogenesis. In conclusion, neurokinin-1 and dopamine D1 receptors are required for the METH-induced striatal cytogenesis while the D2 receptor is without effect. PMID:21652034

Tulloch, Ingrid; Ghazaryan, Nane; Mexhitaj, Ina; Ordonez, Dalila; Angulo, Jesus A

2011-07-01

315

Distinct role of estrogen receptor-alpha and beta on postmenopausal diabetes-induced vascular dysfunction.  

PubMed

Estrogen is known to influence vascular functions and insulin sensitivity, but the relative contribution of estrogen receptor (ER) isoforms in postmenopausal diabetes-induced vascular dysfunction is unclear. The aim of the present study was to delineate the distinct role of estrogen receptor-? and beta ? on the vascular function in ovariectomized diabetic rats. Age matched 60 female sprague dawley rats (200-250g) were divided in nine groups. Bilateral ovariectomy was performed and streptozotocin was used to induce experimental diabetes. Rats were administered with 10?g/kg; s.c. of a nonselective estrogen receptor agonist, 17-? estradiol (E2), selective ER-? agonist (4,4',4?-(4-propyl-[1H] pyrazole-1,3,5-triyl) tris phenol (PPT) and selective ER-? agonist, 2,3-bis(4-hydroxyphenyl)-propionitrile (DPN) for 4weeks after STZ injection. Treatment with selective ER-? agonist and E2 improved the impaired glycemic and lipid profile in ovariectomized diabetic rats, however selective ER-? agonist did not show any effect. Vascular endothelial dysfunction was assessed by acetylcholine and sodium nitroprusside-induced endothelium dependent and independent relaxation in isolated rat aortic ring preparation as well as by electron microscopy of thoracic aorta. Further, serum thiobarbituric acid reactive substances, tumour necrotic factor-alpha and interleukin-1 beta and C-reactive protein were estimated to assess oxidative stress and vascular inflammation. Treatment with ER-? agonist markedly and E2 partially improved vascular function and endothelial integrity along with reduction in serum TBARS and inflammatory cytokines. However, ER-? agonist did not show any improvement in vascular functions, oxidative stress or inflammation. These findings suggest that selective targeting of ER-? receptors results in vasculoprotection in the state of hypoestrogenicity and diabetes. PMID:24967951

Bansal, Seema; Chopra, Kanwaljit

2014-09-15

316

Angiotensin II Induces Vascular Endocannabinoid Release, Which Attenuates Its Vasoconstrictor Effect via CB1 Cannabinoid Receptors*  

PubMed Central

In the vascular system angiotensin II (Ang II) causes vasoconstriction via the activation of type 1 angiotensin receptors. Earlier reports have shown that in cellular expression systems diacylglycerol produced during type 1 angiotensin receptor signaling can be converted to 2-arachidonoylglycerol, an important endocannabinoid. Because activation of CB1 cannabinoid receptors (CB1R) induces vasodilation and reduces blood pressure, we have tested the hypothesis that Ang II-induced 2-arachidonoylglycerol release can modulate its vasoconstrictor action in vascular tissue. Rat and mouse skeletal muscle arterioles and mouse saphenous arteries were isolated, pressurized, and subjected to microangiometry. Vascular expression of CB1R was demonstrated using Western blot and RT-PCR. In accordance with the functional relevance of these receptors WIN55212, a CB1R agonist, caused vasodilation, which was absent in CB1R knock-out mice. Inhibition of CB1Rs using O2050, a neutral antagonist, enhanced the vasoconstrictor effect of Ang II in wild type but not in CB1R knock-out mice. Inverse agonists of CB1R (SR141716 and AM251) and inhibition of diacylglycerol lipase using tetrahydrolipstatin also augmented the Ang II-induced vasoconstriction, suggesting that endocannabinoid release modulates this process via CB1R activation. This effect was independent of nitric-oxide synthase activity and endothelial function. These data demonstrate that Ang II stimulates vascular endocannabinoid formation, which attenuates its vasoconstrictor effect, suggesting that endocannabinoid release from the vascular wall and CB1R activation reduces the vasoconstrictor and hypertensive effects of Ang II. PMID:22787147

Szekeres, Maria; Nadasy, Gyorgy L.; Turu, Gabor; Soltesz-Katona, Eszter; Toth, Zsuzsanna E.; Balla, Andras; Catt, Kevin J.; Hunyady, Laszlo

2012-01-01

317

Angiotensin II induces vascular endocannabinoid release, which attenuates its vasoconstrictor effect via CB1 cannabinoid receptors.  

PubMed

In the vascular system angiotensin II (Ang II) causes vasoconstriction via the activation of type 1 angiotensin receptors. Earlier reports have shown that in cellular expression systems diacylglycerol produced during type 1 angiotensin receptor signaling can be converted to 2-arachidonoylglycerol, an important endocannabinoid. Because activation of CB(1) cannabinoid receptors (CB(1)R) induces vasodilation and reduces blood pressure, we have tested the hypothesis that Ang II-induced 2-arachidonoylglycerol release can modulate its vasoconstrictor action in vascular tissue. Rat and mouse skeletal muscle arterioles and mouse saphenous arteries were isolated, pressurized, and subjected to microangiometry. Vascular expression of CB(1)R was demonstrated using Western blot and RT-PCR. In accordance with the functional relevance of these receptors WIN55212, a CB(1)R agonist, caused vasodilation, which was absent in CB(1)R knock-out mice. Inhibition of CB(1)Rs using O2050, a neutral antagonist, enhanced the vasoconstrictor effect of Ang II in wild type but not in CB(1)R knock-out mice. Inverse agonists of CB(1)R (SR141716 and AM251) and inhibition of diacylglycerol lipase using tetrahydrolipstatin also augmented the Ang II-induced vasoconstriction, suggesting that endocannabinoid release modulates this process via CB(1)R activation. This effect was independent of nitric-oxide synthase activity and endothelial function. These data demonstrate that Ang II stimulates vascular endocannabinoid formation, which attenuates its vasoconstrictor effect, suggesting that endocannabinoid release from the vascular wall and CB(1)R activation reduces the vasoconstrictor and hypertensive effects of Ang II. PMID:22787147

Szekeres, Mária; Nádasy, György L; Turu, Gábor; Soltész-Katona, Eszter; Tóth, Zsuzsanna E; Balla, András; Catt, Kevin J; Hunyady, László

2012-09-01

318

Substance P reduces TNF-?-induced apoptosis in human tenocytes through NK-1 receptor stimulation  

PubMed Central

Background It has been hypothesised that an upregulation of the neuropeptide substance P (SP) and its preferred receptor, the neurokinin-1 receptor (NK-1 R), is a causative factor in inducing tenocyte hypercellularity, a characteristic of tendinosis, through both proliferative and antiapoptotic stimuli. We have demonstrated earlier that SP stimulates proliferation of human tenocytes in culture. Aim The aim of this study was to investigate whether SP can mediate an antiapoptotic effect in tumour necrosis factor-? (TNF-?)-induced apoptosis of human tenocytes in vitro. Results A majority (approximately 75%) of tenocytes in culture were immunopositive for TNF Receptor-1 and TNF Receptor-2. Exposure of the cells to TNF-? significantly decreased cell viability, as shown with crystal violet staining. TNF-? furthermore significantly increased the amount of caspase-10 and caspase-3 mRNA, as well as both BID and cleaved-poly ADP ribosome polymerase (c-PARP) protein. Incubation of SP together with TNF-? resulted in a decreased amount of BID and c-PARP, and in a reduced lactate dehydrogenase release, as compared to incubation with TNF-? alone. The SP effect was blocked with a NK-1 R inhibitor. Discussion This study shows that SP, through stimulation of the NK-1 R, has the ability to reduce TNF-?-induced apoptosis of human tenocytes. Considering that SP has previously been shown to stimulate tenocyte proliferation, the study confirms SP as a potent regulator of cell-turnover in tendon tissue, capable of stimulating hypercellularity through different mechanisms. This gives further support for the theory that the upregulated amount of SP seen in tendinosis could contribute to hypercellularity. PMID:23996004

Backman, Ludvig J; Eriksson, Daniella E; Danielson, Patrik

2014-01-01

319

Oncostatin M (OSM) primes IL-13- and IL-4-induced eotaxin responses in fibroblasts: regulation of the type-II IL-4 receptor chains IL-4Ralpha and IL-13Ralpha1.  

PubMed

Oncostatin M (OSM), a pleiotropic cytokine and a member of the gp130/IL-6 cytokine family, has been implicated in regulation of various chronic inflammatory processes. Previous work has shown that OSM induces eosinophil accumulation in mouse lungs in vivo and stimulates the eosinophil-selective chemokine eotaxin-1 synergistically with IL-4 in vitro. To examine the role of receptor regulation by OSM in synergistic eotaxin-1 responses, we here examine the modulation of the type-II IL-4 receptor (IL-4Ralpha and IL-13Ralpha1) by OSM and other gp130/IL-6 cytokine family members using NIH3T3 fibroblasts and primary mouse lung fibroblasts. We first show that OSM with either IL-13 or IL-4 synergistically induces eotaxin-1 expression in a dose-dependent fashion. Analysis of IL-4Ralpha expression at the protein (Western blot and FACS) and RNA (TAQMAN) levels showed that OSM markedly elevates expression by 3 h. OSM enhanced IL-13Ralpha1 mRNA and induced a smaller but detectable increase in total IL-13Ralpha1 protein. Priming fibroblasts with OSM for 6 h markedly enhanced subsequent IL-13 and IL-4-induced eotaxin-1 responses and STAT6 tyrosine-641 phosphorylation. Regulation of IL-4Ralpha by OSM was sensitive to inhibition of the PI3'K pathway by LY294002. These studies provide novel mechanistic insights in OSM role in regulation of synergistic eotaxin-1 responses and IL-4Ralpha expression in fibroblasts. PMID:19799897

Fritz, Dominik K; Kerr, Christine; Botelho, Fernando; Stampfli, Martin; Richards, Carl D

2009-12-10

320

Agonist-induced polarized trafficking and surface expression of the adenosine 2b receptor in intestinal epithelial cells: role of SNARE proteins  

E-print Network

Agonist-induced polarized trafficking and surface expression of the adenosine 2b receptor-induced polarized trafficking and surface expres- sion of the adenosine 2b receptor in intestinal epithelial cells July 15, 2004; doi:10.1152/ ajpgi.00164.2004.--Adenosine, acting through the A2b receptor, in- duces

Hall, Randy A

321

G protein-coupled receptor 56 regulates mechanical overload-induced muscle hypertrophy.  

PubMed

Peroxisome proliferator-activated receptor gamma coactivator 1-alpha 4 (PGC-1?4) is a protein isoform derived by alternative splicing of the PGC1? mRNA and has been shown to promote muscle hypertrophy. We show here that G protein-coupled receptor 56 (GPR56) is a transcriptional target of PGC-1?4 and is induced in humans by resistance exercise. Furthermore, the anabolic effects of PGC-1?4 in cultured murine muscle cells are dependent on GPR56 signaling, because knockdown of GPR56 attenuates PGC-1?4-induced muscle hypertrophy in vitro. Forced expression of GPR56 results in myotube hypertrophy through the expression of insulin-like growth factor 1, which is dependent on G?12/13 signaling. A murine model of overload-induced muscle hypertrophy is associated with increased expression of both GPR56 and its ligand collagen type III, whereas genetic ablation of GPR56 expression attenuates overload-induced muscle hypertrophy and associated anabolic signaling. These data illustrate a signaling pathway through GPR56 which regulates muscle hypertrophy associated with resistance/loading-type exercise. PMID:25336758

White, James P; Wrann, Christiane D; Rao, Rajesh R; Nair, Sreekumaran K; Jedrychowski, Mark P; You, Jae-Sung; Martínez-Redondo, Vicente; Gygi, Steven P; Ruas, Jorge L; Hornberger, Troy A; Wu, Zhidan; Glass, David J; Piao, Xianhua; Spiegelman, Bruce M

2014-11-01

322

The Aldosterone-Mineralocorticoid Receptor Pathway Exerts Anti-Inflammatory Effects in Endotoxin-Induced Uveitis  

PubMed Central

We have previously shown that the eye is a mineralocorticoid-sensitive organ and we now question the role of mineralocorticoid receptor (MR) in ocular inflammation. The endotoxin-induced uveitis (EIU), a rat model of human intraocular inflammation, was induced by systemic administration of lipopolysaccharide (LPS). Evaluations were made 6 and 24 hours after intraocular injection of aldosterone (simultaneous to LPS injection). Three hours after onset of EIU, the MR and the glucocorticoid metabolizing enzyme 11-beta hydroxysteroid dehydrogenase type 2 (11?-HSD2) expression were down-regulated in iris/ciliary body and the corticosterone concentration was increased in aqueous humor, altering the normal MR/glucocorticoid receptor (GR) balance. At 24 hours, the GR expression was also decreased. In EIU, aldosterone reduced the intensity of clinical inflammation in a dose-dependent manner. The clinical benefit of aldosterone was abrogated in the presence of the MR antagonist (RU26752) and only partially with the GR antagonist (RU38486). Aldosterone reduced the release of inflammatory mediators (6 and 24 hours: TNF-?, IFN-?, MIP-1?) in aqueous humor and the number of activated microglia/macrophages. Aldosterone partly prevented the uveitis-induced MR down-regulation. These results suggest that MR expression and activation in iris/ciliary body could protect the ocular structures against damages induced by EIU. PMID:23152847

Ly, Andre; Leroux les Jardins, Guillaume; Goldenberg, Brigitte; Naud, Marie-Christine; Jonet, Laurent; Besson-Lescure, Bernadette; Jaisser, Frederic; Farman, Nicolette; De Kozak, Yvonne; Behar-Cohen, Francine

2012-01-01

323

The effects of thromboxane receptor antagonists on oestrogen-induced uterotrophic responses in the spontaneously hypertensive rat.  

PubMed Central

1. The possible role of thromboxane in the uterotrophic response to oestrogen, in the spontaneously hypertensive rat was investigated by use of the thromboxane receptor antagonists EP092, AH23848 and BM 13.505. 2. The parameters studied were uterine blood flow (measured by the microsphere technique), uterine wet and dry weights and the concentrations of cytosolic and nuclear oestrogen receptors. 3. The antagonists attenuated oestradiol-induced uterine blood flow and significantly reduced both wet and dry uterine weight. These changes were accompanied by decreases in nuclear oestrogen receptor levels. 4. The results suggest a supportive role for thromboxane in oestradiol-induced uterine growth. PMID:1832065

Kerr, M. B.; Marshall, K.; Senior, J.

1991-01-01

324

CD95/Fas induces cleavage of the GrpL/Gads adaptor and desensitization of antigen receptor signaling  

PubMed Central

The balance between cell survival and cell death is critical for normal lymphoid development. This balance is maintained by signals through lymphocyte antigen receptors and death receptors such as CD95/Fas. In some cells, ligating the B cell antigen receptor can protect the cell from apoptosis induced by CD95. Here we report that ligation of CD95 inhibits antigen receptor-mediated signaling. Pretreating CD40-stimulated tonsillar B cells with anti-CD95 abolished B cell antigen receptor-mediated calcium mobilization. Furthermore, CD95 ligation led to the caspase-dependent inhibition of antigen receptor-induced calcium mobilization and to the activation of mitogen-activated protein kinase pathways in B and T cell lines. A target of CD95-mediated caspase 3-like activity early in the apoptotic process is the adaptor protein GrpL/Gads. GrpL constitutively interacts with SLP-76 via its C-terminal SH3 domain to regulate transcription factors such as NF-AT. Cleavage of GrpL removes the C-terminal SH3 domain so that it is no longer capable of recruiting SLP-76 to the membrane. Transfection of a truncated form of GrpL into Jurkat T cells blocked T cell antigen receptor-induced activation of NF-AT. These results suggest that CD95 signaling can desensitize antigen receptors, in part via cleavage of the GrpL adaptor. PMID:11391000

Yankee, Thomas M.; Draves, Kevin E.; Ewings, Maria K.; Clark, Edward A.; Graves, Jonathan D.

2001-01-01

325

Role of leptin receptor-induced STAT3 signaling in modulation of intestinal and hepatic inflammation in mice  

Microsoft Academic Search

Leptin-deficient ob\\/ob mice are resis- tant to dextran sulfate sodium (DSS)-induced coli- tis and Con A-induced hepatitis. However, the sig- nal transduction pathways involved have not been identified. The present study investigated the effect of leptin-induced STAT3 signaling in the DSS and Con A models. Mice carrying a leptin receptor (LEPR) gene mutant for Y1138 (s\\/s mice), with abrogated leptin-induced

Melissa E. Gove; Davina H. Rhodes; Maria Pini; Jantine W. van Baal; Joseph A. Sennello; Raja Fayad; Robert J. Cabay; Martin G. Myers Jr.; Giamila Fantuzzi

2008-01-01

326

Sucrose-induced Receptor Kinase SIRK1 Regulates a Plasma Membrane Aquaporin in Arabidopsis*  

PubMed Central

The transmembrane receptor kinase family is the largest protein kinase family in Arabidopsis, and it contains the highest fraction of proteins with yet uncharacterized functions. Here, we present functions of SIRK1, a receptor kinase that was previously identified with rapid transient phosphorylation after sucrose resupply to sucrose-starved seedlings. SIRK1 was found to be an active kinase with increasing activity in the presence of an external sucrose supply. In sirk1 T-DNA insertional mutants, the sucrose-induced phosphorylation patterns of several membrane proteins were strongly reduced; in particular, pore-gating phosphorylation sites in aquaporins were affected. SIRK1-GFP fusions were found to directly interact with aquaporins in affinity pull-down experiments on microsomal membrane vesicles. Furthermore, protoplast swelling assays of sirk1 mutants and SIRK1-GFP expressing lines confirmed a direct functional interaction of receptor kinase SIRK1 and aquaporins as substrates for phosphorylation. A lack of SIRK1 expression resulted in the failure of mutant protoplasts to control water channel activity upon changes in external sucrose concentrations. We propose that SIRK1 is involved in the regulation of sucrose-specific osmotic responses through direct interaction with and activation of an aquaporin via phosphorylation and that the duration of this response is controlled by phosphorylation-dependent receptor internalization. PMID:23820729

Wu, Xu Na; Sanchez Rodriguez, Clara; Pertl-Obermeyer, Heidi; Obermeyer, Gerhard; Schulze, Waltraud X.

2013-01-01

327

Paradoxical downregulation of CXC chemokine receptor 4 induced by polyphemusin II-derived antagonists.  

PubMed

CXC chemokine receptor 4 (CXCR4) is a G protein-coupled receptor implicated in cell entry of T-cell line-tropic HIV-1 strains. CXCR4 and its ligand stromal cell derived factor-1 (SDF-1)/CXCL12 play pivotal parts in many physiological processes and pathogenetic conditions (e.g., immune cell-homing and cancer metastasis). We previously developed the potent CXCR4 antagonist T140 from structure-activity relationship studies of the antimicrobial peptide polyphemusin II. T140 and its derivatives have been exploited in biological and biomedical studies for the SDF-1/CXCR4 axis. We investigated receptor localization upon ligand stimulation using fluorescent SDF-1 and T140 derivatives as well as a specific labeling technique for cellular-membrane CXCR4. Fluorescent T140 derivatives induced translocation of CXCR4 into the perinuclear region as observed by treatment with fluorescent SDF-1. T140 derivative-mediated internalization of CXCR4 was also monitored by the coiled-coil tag-probe system. These findings demonstrated that the CXCR4 antagonistic activity and anti-HIV activity of T140 derivatives were derived (at least in part) from antagonist-mediated receptor internalization. PMID:22486464

Masuda, Ryo; Oishi, Shinya; Tanahara, Noriko; Ohno, Hiroaki; Hirasawa, Akira; Tsujimoto, Gozoh; Yano, Yoshiaki; Matsuzaki, Katsumi; Navenot, Jean-Marc; Peiper, Stephen C; Fujii, Nobutaka

2012-06-20

328

Opiate Receptor Knockout Mice Define mu Receptor Roles in Endogenous Nociceptive Responses and Morphine-Induced Analgesia  

Microsoft Academic Search

Morphine produces analgesia at opiate receptors expressed in nociceptive circuits. mu , delta , and kappa opiate receptor subtypes are expressed in circuits that can modulate nociception and receive inputs from endogenous opioid neuropeptide ligands. The roles played by each receptor subtype in nociceptive processing in drug-free and morphine-treated states have not been clear, however. We produced homologous, recombinant mu

Ichiro Sora; Nobuyuki Takahashi; Masahiko Funada; Hiroshi Ujike; Randal S. Revay; David M. Donovan; Lucinda L. Miner; George R. Uhl

1997-01-01

329

Involvement of histamine H1 and H2 receptors in hypothermia induced by ionizing radiation in guinea pigs  

SciTech Connect

Radiation-induced hypothermia was examined in guinea pigs. Exposure to the head alone or whole-body irradiation-induced hypothermia, whereas exposure of the body alone produced a small insignificant response. Systemic injection of disodium cromoglycate (a mast cell stabilizer) and cimetidine (H2-receptor antagonist) had no effect on radiation-induced hypothermia, whereas systemic and central administration of mepyramine (H1-receptor antagonist) or central administration disodium cromoglycate or cimetidine attenuated it, indicating the involvement of central histamine through both H1 and H2 receptors in this response. Serotonin is not involved, since the serotonin antagonist methysergide had no effect on radiation-induced hypothermia. These results indicate that central histaminergic systems may be involved in radiation-induced hypothermia.

Kandasamy, S.B.; Hunt, W.A.

1988-01-01

330

TNF-? reduces g0s2 expression and stimulates lipolysis through PPAR-? inhibition in 3T3-L1 adipocytes.  

PubMed

Tumor necrosis factor-? (TNF-?) is a multifunctional cytokine that acts as a mediator of obesity-linked insulin resistance (IR). It is commonly accepted that macrophage-derived TNF-? acts in a paracrine manner on adjacent adipocytes, induces lipolysis, which contributes to obesity-linked hyperglycemia. Several studies suggested that G0/G1 switch gene 2 (g0s2) was up-regulated during adipogenesis, and its protein could be degraded in response to TNF-? stimulation. The aim of the present work was to investigate the transcriptional regulation of g0s2 by TNF-? stimulation. In this study, 3T3-L1 pre-adipocytes were differentiated, and treated with TNF-? for 24h. The effects of TNF-? on lipolysis and lipase expression were then examined. Our results revealed that TNF-? exerted dose- and time-dependent lipolytic effects, which could be partially reversed by overexpression of g0s2 and peroxisome proliferator-activated receptor-? (ppar-?). In addition, TNF-? treatment significantly reduced the expression of adiponectin, ppar-?, hormone-sensitive Lipase (hsl), adipose triglyceride lipase (atgl) as well as ATGL co-factors. Interestingly, TNF-? significantly decreased adiponectin and PPAR-? protein levels, while treatment with the proteasomal inhibitor MG-132 maintained PPAR-? levels. Degradation of PPAR-? almost completely abolished the binding of PPAR-? to the g0s2 promoter in adipocytes treated with TNF-?. We propose that proteasomal degradation of PPAR-? and the reduction of g0s2 content are permissive for prolonged TNF-? induced lipolysis. PMID:24993166

Jin, Dan; Sun, Jun; Huang, Jing; He, Yiduo; Yu, An; Yu, Xiaoling; Yang, Zaiqing

2014-10-01

331

Irinotecan induces steroid and xenobiotic receptor (SXR) signaling to detoxification pathway in colon cancer cells  

PubMed Central

Background Resistance to chemotherapy remains one of the principle obstacles to the treatment of colon cancer. In order to identify the molecular mechanism of this resistance, we investigated the role of the steroid and xenobiotic receptor (SXR) in the induction of drug resistance. Indeed, this nuclear receptor plays an important role in response to xenobiotics through the upregulation of detoxification genes. Following drug treatments, SXR is activated and interacts with the retinoid X receptor (RXR) to induce expression of some genes involved in drug metabolism such as phase I enzyme (like CYP), phase II enzymes (like UGT) and transporters (e.g. MDR1). Results In this study, we have shown that endogenous SXR is activated in response to SN-38, the active metabolite of the anticancer drug irinotecan, in human colon cancer cell lines. We have found that endogenous SXR translocates into the nucleus and associates with RXR upon SN-38 treatment. Using ChIP, we have demonstrated that endogenous SXR, following its activation, binds to the native promoter of the CYP3A4 gene to induce its expression. RNA interference experiments confirmed SXR involvement in CYP3A4 overexpression and permitted us to identify CYP3A5 and MRP2 transporter as SXR target genes. As a consequence, cells overexpressing SXR were found to be less sensitive to irinotecan treatment. Conclusions Altogether, these results suggest that the SXR pathway is involved in colon cancer irinotecan resistance in colon cancer cell line via the upregulation of select detoxification genes. PMID:21733184

2011-01-01

332

Ligand-induced homotypic and heterotypic clustering of apolipoprotein E receptor 2.  

PubMed

ApoE Receptor 2 (ApoER2) and the very low density lipoprotein receptor (VLDLR) are type I transmembrane proteins belonging to the LDLR family of receptors. They are neuronal proteins found in synaptic compartments that play an important role in neuronal migration during development. ApoER2 and VLDLR bind to extracellular glycoproteins, such as Reelin and F-spondin, which leads to phosphorylation of adaptor proteins and subsequent activation of downstream signaling pathways. It is thought that ApoER2 and VLDLR undergo clustering upon binding to their ligands, but no direct evidence of clustering has been shown. Here we show strong clustering of ApoER2 induced by the dimeric ligands Fc-RAP, F-spondin, and Reelin but relatively weak clustering with the ligand apoE in the absence of lipoproteins. This clustering involves numerous proteins besides ApoER2, including amyloid precursor protein and the synaptic adaptor protein PSD-95. Interestingly, we did not observe strong clustering of ApoER2 with VLDLR. Clustering was modulated by both extracellular and intracellular domains of ApoER2. Together, our data demonstrate that several multivalent ligands for ApoER2 induce clustering in transfected cells and primary neurons and that these complexes included other synaptic molecules, such as APP and PSD-95. PMID:24755222

Divekar, Shailaja D; Burrell, Teal C; Lee, Jennifer E; Weeber, Edwin J; Rebeck, G William

2014-06-01

333

Dopamine D3 Receptor Inactivation Attenuates Cocaine-Induced Conditioned Place Preference in Mice  

PubMed Central

The dopamine (DA) D3 receptor (D3R) has received much attention in medication development for treatment of addiction. However, the functional role of the D3R in drug reward and addiction has been a matter of debate. We recently reported that D3 receptor-knockout (D3?/?) mice display increased vulnerability to cocaine self-administration, which we interpret as a compensatory response to attenuated cocaine reward after D3R deletion. Here we report that D3?/? mice displayed attenuated cocaine-induced conditioned place response (CPP) compared to wild-type mice. Similarly, blockade of brain D3Rs by YQA-14, a novel DA D3 receptor antagonist, significantly and dose-dependently inhibits acquisition and expression of cocaine-induced CPP in WT mice, but not in D3?/? mice. These findings suggest that: 1) D3Rs play an important role in mediating cocaine’s rewarding effects; and 2) YQA-14 is a highly potent and selective D3R antagonist in vivo, which deserves further study as a candidate for treatment of cocaine addiction. PMID:23643749

Song, Rui; Zhang, Hai-Ying; Peng, Xiao-Qing; Su, Rui-Bin; Yang, Ri-Fang; Li, Jin; Xi, Zheng-Xiong; Gardner, Eliot L.

2013-01-01

334

The Lysophosphatidic Acid Type 2 Receptor Is Required for Protection Against Radiation-Induced Intestinal Injury  

PubMed Central

Background & Aims We recently identified lysophosphatidic acid (LPA) as a potent antiapoptotic agent for the intestinal epithelium. The objective of the present study was to evaluate the effect of octadecenyl thiophosphate (OTP), a novel rationally designed, metabolically stabilized LPA mimic, on radiation-induced apoptosis of intestinal epithelial cells in vitro and in vivo Methods The receptors and signaling pathways activated by OTP were examined in IEC-6 and RH7777 cell lines and wild-type and LPA1 and LPA2 knockout mice exposed to different apoptotic stimuli Results OTP was more efficacious than LPA in reducing gamma irradiation–, camptothecin-, or tumor necrosis factor ?/cycloheximide–induced apoptosis and caspase-3-8, and caspase-9 activity in the IEC-6 cell line. In RH7777 cells lacking LPA receptors, OTP selectively protected LPA2 but not LPA1 and LPA3 transfectants. In C57BL/6 and LPA1 knockout mice exposed to 15 Gy gamma irradiation, orally applied OTP reduced the number of apoptotic bodies and activated caspase-3–positive cells but was ineffective in LPA2 knockout mice. OTP, with higher efficacy than LPA, enhanced intestinal crypt survival in C57BL/6 mice but was without any effect in LPA2 knockout mice. Intraperitoneally administered OTP reduced death caused by lethal dose (LD)100/30 radiation by 50%. Conclusions Our data indicate that OTP is a highly effective antiapoptotic agent that engages similar prosurvival pathways to LPA through the LPA2 receptor subtype. PMID:17484878

Deng, Wenlin; Shuyu, E; Tsukahara, Ryoko; Valentine, William J.; Durgam, Gangadhar; Gududuru, Veeresa; Balazs, Louisa; Manickam, Venkatraman; Arsura, Marcello; Vanmiddlesworth, Lester; Johnson, Leonard R.; Parrill, Abby L.; Miller, Duane D.; Tigyi, Gabor

2010-01-01

335

Dopamine-Induced Apoptosis of Lactotropes Is Mediated by the Short Isoform of D2 Receptor  

PubMed Central

Dopamine, through D2 receptor (D2R), is the major regulator of lactotrope function in the anterior pituitary gland. Both D2R isoforms, long (D2L) and short (D2S), are expressed in lactotropes. Although both isoforms can transduce dopamine signal, they differ in the mechanism that leads to cell response. The administration of D2R agonists, such as cabergoline, is the main pharmacological treatment for prolactinomas, but resistance to these drugs exists, which has been associated with alterations in D2R expression. We previously reported that dopamine and cabergoline induce apoptosis of lactotropes in primary culture in an estrogen-dependent manner. In this study we used an in vivo model to confirm the permissive action of estradiol in the apoptosis of anterior pituitary cells induced by D2R agonists. Administration of cabergoline to female rats induced apoptosis, measured by Annexin-V staining, in anterior pituitary gland from estradiol-treated rats but not from ovariectomized rats. To evaluate the participation of D2R isoforms in the apoptosis induced by dopamine we used lactotrope-derived PR1 cells stably transfected with expression vectors encoding D2L or D2S receptors. In the presence of estradiol, dopamine induced apoptosis, determined by ELISA and TUNEL assay, only in PR1-D2S cells. To study the role of p38 MAPK in apoptosis induced by D2R activation, anterior pituitary cells from primary culture or PR1-D2S were incubated with an inhibitor of the p38 MAPK pathway (SB203850). SB203580 blocked the apoptotic effect of D2R activation in lactotropes from primary cultures and PR1-D2S cells. Dopamine also induced p38 MAPK phosphorylation, determined by western blot, in PR1-D2S cells and estradiol enhanced this effect. These data suggest that, in the presence of estradiol, D2R agonists induce apoptosis of lactotropes by their interaction with D2S receptors and that p38 MAPK is involved in this process. PMID:21464994

Radl, Daniela Betiana; Ferraris, Jimena; Boti, Valeria; Seilicovich, Adriana; Sarkar, Dipak Kumar; Pisera, Daniel

2011-01-01

336

ACE inhibitor or angiotensin II receptor antagonist attenuates diabetic neuropathy in streptozotocin-induced diabetic rats.  

PubMed

ACE inhibition and/or blocking of the angiotensin II receptor are recognized as first-line treatment for nephropathy and cardiovascular disease in diabetic patients. However, little information is available about the potential benefits of these drugs on diabetic neuropathy. We examined vascular and neural activity in streptozotocin-induced diabetic rats that were treated for 12 weeks with enalapril, an ACE inhibitor, or L-158809, an angiotensin II receptor blocker. A prevention protocol (group 1) as well as three intervention protocols (treatment was initiated after 4, 8, or 12 weeks of diabetes [groups 2, 3, and 4, respectively]) were used. Endoneurial blood flow and motor nerve conduction velocity (MNCV) were impaired in all groups of untreated diabetic rats. In group 1, treatment of diabetic rats with enalapril or L-158809 partially prevented the diabetes-induced decrease in endoneurial blood flow and MNCV. In groups 2-4, intervention with enalapril was more effective in reversing the diabetes-induced impairment in endoneurial blood flow and MNCV than L-158809. The superoxide level in the aorta and epineurial arterioles of diabetic rats was increased. Treatment of diabetic rats with enalapril or L-158809 reduced the superoxide level in the aorta in all groups but was less effective in epineurial arterioles. Acetylcholine and calcitonin gene-related peptide (CGRP) cause vasodilation in epineurial arterioles of the sciatic nerve, which was impaired by diabetes. Treatment of diabetic rats (all groups) with enalapril or L-158809 completely prevented/reversed the diabetes-induced impairment in CGRP-mediated vascular relaxation. Treatment with enalapril or L-158809 was also effective in improving impaired acetylcholine-mediated vasodilation, but the efficacy was diminished from groups 1 to 4. These studies suggest that ACE inhibitors and/or angiotensin II receptor blockers may be effective treatments for diabetes and vascular and neural dysfunction. However, the efficacy of these treatments may be dependent on when the treatment is initiated. PMID:16443766

Coppey, Lawrence J; Davidson, Eric P; Rinehart, Thomas W; Gellett, Jill S; Oltman, Christine L; Lund, Donald D; Yorek, Mark A

2006-02-01

337

Activation of the Farnesoid X Receptor Induces Hepatic Expression and Secretion of Fibroblast Growth Factor 21*  

PubMed Central

Previous studies have shown that starvation or consumption of a high fat, low carbohydrate (HF-LC) ketogenic diet induces hepatic fibroblast growth factor 21 (FGF21) gene expression in part by activating the peroxisome proliferator-activated receptor-? (PPAR?). Using primary hepatocyte cultures to screen for endogenous signals that mediate the nutritional regulation of FGF21 expression, we identified two sources of PPAR? activators (i.e. nonesterified unsaturated fatty acids and chylomicron remnants) that induced FGF21 gene expression. In addition, we discovered that natural (i.e. bile acids) and synthetic (i.e. GW4064) activators of the farnesoid X receptor (FXR) increased FGF21 gene expression and secretion. The effects of bile acids were additive with the effects of nonesterified unsaturated fatty acids in regulating FGF21 expression. FXR activation of FGF21 gene transcription was mediated by an FXR/retinoid X receptor binding site in the 5?-flanking region of the FGF21 gene. FGF19, a gut hormone whose expression and secretion is induced by intestinal bile acids, also increased hepatic FGF21 secretion. Deletion of FXR in mice suppressed the ability of an HF-LC ketogenic diet to induce hepatic FGF21 gene expression. The results of this study identify FXR as a new signaling pathway activating FGF21 expression and provide evidence that FXR activators work in combination with PPAR? activators to mediate the stimulatory effect of an HF-LC ketogenic diet on FGF21 expression. We propose that the enhanced enterohepatic flux of bile acids during HF-LC consumption leads to activation of hepatic FXR and FGF19 signaling activity and an increase in FGF21 gene expression and secretion. PMID:22661717

Cyphert, Holly A.; Ge, Xuemei; Kohan, Alison B.; Salati, Lisa M.; Zhang, Yanqiao; Hillgartner, F. Bradley

2012-01-01

338

Face-washing behavior induced by the group I metabotropic glutamate receptor agonist (S)-3,5-DHPG in mice is mediated by mGlu1 receptor.  

PubMed

It is known for the non-selective group I metabotropic glutamate (mGlu) receptors agonist (S)-3,5-dihydroxyphenylglycine (S-3,5-DHPG) to cause convulsions, which are mediated by mGlu1 receptor. However, the behavioral changes other than convulsions caused by (S)-3,5-DHPG have not been well studied. The purpose of the present study was to explore the behavioral changes elicited by activation of group I mGlu receptors with (S)-3,5-DHPG and to clarify which, mGlu1 receptor or mGlu5 receptor, is responsible for such behavior. (S)-3,5-DHPG at doses of 3-30 nmol caused characteristic face-washing behavior. This behavioral change was inhibited by both the competitive mGlu1 receptor antagonists (RS)-1-aminoindan-1,5-dicarboxylic acid (AIDA) and (S)-4-carboxyphenylglycine (S-4CPG) and the non-competitive mGlu1 receptor antagonist, 4-[1-(2-fluoropyridin-3-yl)-5-methyl-1H-1,2,3-triazol-4-yl]-N-isopropyl-N-methyl-3,6-dihydropyridine-1(2H)-carboxamide (FTIDC), but not by the mGlu5 receptor antagonist 2-Methyl-6-(phenylethynyl)pyridine hydrochloride (MPEP), the mGlu2/3 receptor agonist (-)-2-oxa-4-aminobicyclo[3.1.0]hexane-4,6-dicarboxylate (LY379268), the mGlu2/3 receptor antagonist (2S)-2-amino-2-[(1S,2S)-2-carboxycycloprop-1-yl]-3-(xanth-9-yl) propanoic acid (LY341495), the N-methyl-d-asparate (NMDA) receptor antagonist 5R,10S-(+)-5-methyl-10,11-dihydro-5H-dibenzo[a,d]cyclohepten-5,10-imine hydrogen maleate (MK-801), or the competitive non-NMDA receptor antagonist 2,3-dioxo-6-nitro-1,2,3,4-tetrahydrobenzo[f]quinoxaline-7-sulfonamide (NBQX). These findings indicate that face-washing behavior is due to selective activation of mGlu1 receptor by (S)-3,5-DHPG, and that the face-washing behavior induced by (S)-3,5-DHPG in mice can be used for in vivo testing of the antagonistic potency of both competitive and non-competitive mGlu1 receptor antagonists. PMID:18378225

Hikichi, Hirohiko; Iwahori, Yuki; Murai, Takeshi; Maehara, Shunsuke; Satow, Akio; Ohta, Hisashi

2008-05-31

339

NADPH oxidase is the primary source of superoxide induced by NMDA receptor activation  

PubMed Central

Neuronal NMDA receptor (NMDAR) activation leads to the formation of superoxide, which normally acts in cell signaling. With extensive NMDAR activation, the resulting superoxide production leads to neuronal death. It is widely held that NMDA-induced superoxide production originates from the mitochondria, but definitive evidence for this is lacking. We evaluated the role of the cytoplasmic enzyme NADPH oxidase in NMDA-induced superoxide production. Neurons in culture and in mouse hippocampus responded to NMDA with a rapid increase in superoxide production, followed by neuronal death. These events were blocked by the NADPH oxidase inhibitor apocynin and in neurons lacking the p47phox subunit, which is required for NADPH oxidase assembly. Superoxide production was also blocked by inhibiting the hexose monophosphate shunt, which regenerates the NADPH substrate, and by inhibiting protein kinase C zeta, which activates the NADPH oxidase complex. These findings identify NADPH oxidase as the primary source of NMDA-induced superoxide production. PMID:19503084

Brennan, Angela M; Suh, Sang Won; Won, Seok Joon; Narasimhan, Purnima; Kauppinen, Tiina M; Lee, Hokyou; Edling, Ylva; Chan, Pak H; Swanson, Raymond A

2009-01-01

340

Toll-like receptor 4 implicated in acute lung injury induced by paraquat poisoning in mice  

PubMed Central

Objective: To investigate the possible relationship and mechanism of Toll-like receptor 4 (TLR4) and acute lung injury induced by paraquat (PQ) poisoning. Methods: Male wild type mice and male TLR4-knockout mice were used in this study. After paraquat treatment for 24 hours, mice were euthanized and pathology, TLR4 expression and pro-inflammatory cytokines were evaluated. Results: Wild type mice showed deteriorated lung injury, pathological damages and increased TLR4 expression and pulmonary TNF-?, IL-1? and NF-?B p65 levels after PQ treatment. TLR4-deficient mice were significantly resistant to paraquat-induced lung injury. Conclusion: TLR4 may be required as a mediator and may play an important role in acute lung injury induced by paraquat.

Liu, Wei; Shan, Li-Ping; Dong, Xue-Song; Liu, Zhi

2014-01-01

341

Role of B61, the Ligand for the Eck Receptor Tyrosine Kinase, in TNF- ?-Induced Angiogenesis  

NASA Astrophysics Data System (ADS)

B61, a cytokine-inducible endothelial gene product, is the ligand for the Eck receptor protein tyrosine kinase (RPTK). Expression of a B61-immunoglobulin chimera showed that B61 could act as an angiogenic factor in vivo and a chemoattractant for endothelial cells in vitro. The Eck RPTK was activated by tumor necrosis factor-? (TNF-?) through induction of B61, and an antibody to B61 attenuated angiogenesis induced by TNF-? but not by basic fibroblast growth factor. This finding suggests the existence of an autocrine or paracrine loop involving activation of the Eck RPTK by its inducible ligand B61 after an inflammatory stimulus, the net effect of which would be to promote angiogenesis, a hallmark of chronic inflammation.

Pandey, Akhilesh; Shao, Haining; Marks, Rory M.; Polverini, Peter J.; Dixit, Vishva M.

1995-04-01

342

Ursolic Acid, a Pentacyclin Triterpene, Potentiates TRAIL-induced Apoptosis through p53-independent Up-regulation of Death Receptors  

PubMed Central

Discovery of the molecular targets of traditional medicine and its chemical footprints can validate the use of such medicine. In the present report, we investigated the effect of ursolic acid (UA), a pentacyclic triterpenoid found in rosemary and holy basil, on apoptosis induced by TRAIL. We found that UA potentiated TRAIL-induced apoptosis in cancer cells. In addition, UA also sensitized TRAIL-resistant cancer cells to the cytokine. When we investigated the mechanism, we found that UA down-regulated cell survival proteins and induced the cell surface expression of both TRAIL receptors, death receptors 4 and 5 (DR4 and -5). Induction of receptors by UA occurred independently of cell type. Gene silencing of either receptor by small interfering RNA reduced the apoptosis induced by UA and the effect of TRAIL. In addition, UA also decreased the expression of decoy receptor 2 (DcR2) but not DcR1. Induction of DRs was independent of p53 because UA induced DR4 and DR5 in HCT116 p53?/? cells. Induction of DRs, however, was dependent on JNK because UA induced JNK, and its pharmacologic inhibition abolished the induction of the receptors. The down-regulation of survival proteins and up-regulation of the DRs required reactive oxygen species (ROS) because UA induced ROS, and its quenching abolished the effect of the terpene. Also, potentiation of TRAIL-induced apoptosis by UA was significantly reduced by both ROS quenchers and JNK inhibitor. In addition, UA was also found to induce the expression of DRs, down-regulate cell survival proteins, and activate JNK in orthotopically implanted human colorectal cancer in a nude mouse model. Overall, our results showed that UA potentiates TRAIL-induced apoptosis through activation of ROS and JNK-mediated up-regulation of DRs and down-regulation of DcR2 and cell survival proteins. PMID:21156789

Prasad, Sahdeo; Yadav, Vivek R.; Kannappan, Ramaswamy; Aggarwal, Bharat B.

2011-01-01

343

The Islet Estrogen Receptor-? Is Induced by Hyperglycemia and Protects Against Oxidative Stress-Induced Insulin-Deficient Diabetes  

PubMed Central

The female steroid, 17?-estradiol (E2), is important for pancreatic ?-cell function and acts via at least three estrogen receptors (ER), ER?, ER?, and the G-protein coupled ER (GPER). Using a pancreas-specific ER? knockout mouse generated using the Cre-lox-P system and a Pdx1-Cre transgenic line (PER?KO?/?), we previously reported that islet ER? suppresses islet glucolipotoxicity and prevents ?-cell dysfunction induced by high fat feeding. We also showed that E2 acts via ER? to prevent ?-cell apoptosis in vivo. However, the contribution of the islet ER? to ?-cell survival in vivo, without the contribution of ER? in other tissues is still unclear. Using the PER?KO?/? mouse, we show that ER? mRNA expression is only decreased by 20% in the arcuate nucleus of the hypothalamus, without a parallel decrease in the VMH, making it a reliable model of pancreas-specific ER? elimination. Following exposure to alloxan-induced oxidative stress in vivo, female and male PER?KO?/? mice exhibited a predisposition to ?-cell destruction and insulin deficient diabetes. In male PER?KO?/? mice, exposure to E2 partially prevented alloxan-induced ?-cell destruction and diabetes. ER? mRNA expression was induced by hyperglycemia in vivo in islets from young mice as well as in cultured rat islets. The induction of ER? mRNA by hyperglycemia was retained in insulin receptor-deficient ?-cells, demonstrating independence from direct insulin regulation. These findings suggest that induction of ER? expression acts to naturally protect ?-cells against oxidative injury. PMID:24498408

Kilic, Gamze; Alvarez-Mercado, Ana I.; Zarrouki, Bader; Opland, Darren; Liew, Chong Wee; Alonso, Laura C.; Myers, Martin G.; Jonas, Jean-Christophe; Poitout, Vincent; Kulkarni, Rohit N.; Mauvais-Jarvis, Franck

2014-01-01

344

VGluT3+ Primary Afferents Play Distinct Roles in Mechanical and Cold Hypersensitivity Depending on Pain Etiology.  

PubMed

Sensory nerve fibers differ not only with respect to their sensory modalities and conduction velocities, but also in their relative roles for pain hypersensitivity. It is presently largely unknown which types of sensory afferents contribute to various forms of neuropathic and inflammatory pain hypersensitivity. Vesicular glutamate transporter 3-positive (VGluT3(+)) primary afferents, for example, have been implicated in mechanical hypersensitivity after inflammation, but their role in neuropathic pain remains under debate. Here, we investigated a possible etiology-dependent contribution of VGluT3(+) fibers to mechanical and cold hypersensitivity in different models of inflammatory and neuropathic pain. In addition to VGluT3(-/-) mice, we used VGluT3-channelrhodopsin 2 mice to selectively stimulate VGluT3(+) sensory afferents by blue light, and to assess light-evoked behavior in freely moving mice. We show that VGluT3(-/-) mice develop reduced mechanical hypersensitivity upon carrageenan injection. Both mechanical and cold hypersensitivity were reduced in VGluT3(-/-) mice in neuropathic pain evoked by the chemotherapeutic oxaliplatin, but not in the chronic constriction injury (CCI) model of the sciatic nerve. Further, we provide direct evidence that, despite not mediating painful stimuli in naive mice, activation of VGluT3(+) sensory fibers by light elicits pain behavior in the oxaliplatin but not the CCI model. Immunohistochemical and electrophysiological data support a role of transient receptor potential melastatin 8-mediated facilitation of synaptic strength at the level of the dorsal horn as an underlying mechanism. Together, we demonstrate that VGluT3(+) fibers contribute in an etiology-dependent manner to the development of mechano-cold hypersensitivity. PMID:25186747

Draxler, Peter; Honsek, Silke Doris; Forsthuber, Liesbeth; Hadschieff, Viktoria; Sandkühler, Jürgen

2014-09-01

345

Parathyroid hormone induces the Nrna family of nuclear orphan receptors in vivo  

SciTech Connect

Parathyroid hormone (PTH) has both anabolic and catabolic effects on bone metabolism, although the molecular mechanisms mediating these effects are largely unknown. Among the transcription factors induced by Pth in osteoblasts are the nerve growth factor-inducible factor B (NR4A; NGFI-B) family of orphan nuclear receptors: Nurr1, Nur77, and NOR-1. PTH induces NR4A members through the cAMP-protein kinase A (PKA) pathway in vitro. We report here that PTH rapidly and transiently induced expression of all three NR4A genes in PTH-target tissues in vivo. In calvaria, long bones, and kidneys, NR4A induction was maximal 0.5-1 h after a single intraperitoneal (i.p.) injection of 80 {mu}g/kg PTH. Nur77 demonstrated the highest expression, followed, in order, by Nurr1 and NOR-1. In calvaria and long bone, PTH-induced expression of each NR4A gene was detectable at 10 {mu}g/kg i.p. with maximum induction at 40-80 {mu}g/kg. PTH (3-34) did not induce NR4A mRNA levels in calvaria, long bone, and kidney in vivo, confirming our in vitro results that NR4A genes are induced primarily through the cAMP-PKA pathway. The magnitude of PTH-induced NR4A expression was comparable in vivo and in vitro. However, NR4A mRNA levels peaked and returned to baseline faster in vivo. Both in vivo and in vitro, PTH induced NR4A pre-mRNA levels suggesting that induction of these genes is, at least in part, through activation of mRNA synthesis. The in vivo induction of the NR4A family members by PTH suggests their involvement in, at least some, PTH-induced changes in bone metabolism.

Pirih, Flavia Q. [Division of Diagnostic and Surgical Sciences, UCLA School of Dentistry, Los Angeles, CA 90095 (United States)]. E-mail: fqpirih@ucla.edu; Aghaloo, Tara L. [Division of Diagnostic and Surgical Sciences, UCLA School of Dentistry, Los Angeles, CA 90095 (United States)]. E-mail: taghaloo@ucla.edu; Bezouglaia, Olga [Division of Diagnostic and Surgical Sciences, UCLA School of Dentistry, Los Angeles, CA 90095 (United States)]. E-mail: obezougl@ucla.edu; Nervina, Jeanne M. [Section of Orthodontics, UCLA School of Dentistry, Los Angeles, CA 90095 (United States)]. E-mail: jnervina@ucla.edu; Tetradis, Sotirios [Division of Diagnostic and Surgical Sciences, UCLA School of Dentistry, Los Angeles, CA 90095 (United States); UCLA Molecular Biology Institute, Los Angeles, CA 90095 (United States); E-mail: sotirist@dent.ucla.edu

2005-07-01

346

Pathogen recognition receptors in channel catfish: II. Identification, phylogeny and expression of retinoic acid-inducible gene I (RIG-I)-like receptors (RLRs).  

PubMed

Vertebrates including teleost fish have evolved an array of pathogen recognition receptors (PRRs) for detecting and responding to various pathogen-associated molecular patterns (PAMPs), including Toll-like receptors (TLRs), nucleotide-binding domain, leucine-rich repeat containing receptors (NLRs), and the retinoic acid inducible gene I (RIG-I) like receptors (RLRs). As a part of the series of studies targeted to characterize catfish PRRs, we described 22 NLR receptors in the sister contribution. Here in this study, we focused on cytosolic PRRs recognizing nucleotide pathogen-associated molecular patterns (PAMPs) of invading viruses, the retinoic acid-inducible gene I (RIG-I)-like receptors (RLR receptors). Three RLRs with DExD/H domain containing RNA helicases, retinoic acid inducible gene-I (RIG-I), melanoma differentiation-associated gene 5 (MDA5) and laboratory of genetics and physiology 2 (LGP2), were identified from channel catfish, Ictalurus punctatus. The catfish RIG-I encodes 937 amino acids that contains two CARDs, a DExDc, a HELICc and a RD domains. MDA5 encodes 1005 amino acids with all the domains identified for RIG-I. LGP2 encodes 677 amino acids that contain other domains but not the CARD domain at the N-terminus. Phylogenetic analyses of the three genes of catfish showed close clustering with their counterparts from other teleost fish. All the genes were found to be constitutively expressed in various tissues of catfish with minor variations. Channel catfish ovarian cells when infected with channel catfish virus showed significant increase in the transcript abundance of all the three genes. Further, RLR genes showed significant increases in expression in the liver tissue collected at different time-points after bacterial infection as well. The results indicate that the catfish RLRs may play important roles in antiviral and anti-bacterial immune responses. PMID:22387588

Rajendran, K V; Zhang, Jiaren; Liu, Shikai; Peatman, Eric; Kucuktas, Huseyin; Wang, Xiuli; Liu, Hong; Wood, Theresa; Terhune, Jeffery; Liu, Zhanjiang

2012-07-01

347

Activated Mast Cells Are Fibrogenic for 3T3 Fibroblasts  

Microsoft Academic Search

The extent of mast cell direct involvement in fibrosis is not defined as yet. In the present study we assessed whether long-term co-culture (up to 7 d) of functionally active rat peritoneal mast cells with 3T3 mouse fibroblasts and mast cell activation can affect fibroblast proliferation and collagen production. Co-culture of subconfluent 3T3 fibroblasts with resting mast cells or with

Francesca Levi-Schaffer; Evelina Rubinchik

1995-01-01

348

Diminished baroreflex-induced vasoconstriction following alpha-2 adrenergic receptor blockade in humans.  

PubMed

The relative contribution of alpha adrenergic receptor subtypes in the transduction of sympathetic nerve activity (SNA) during carotid baroreflex (CBR) engagement is not well understood. Therefore, we compared the hemodynamic consequence of CBR-mediated sympatho-excitation via neck pressure (NP) before and after alpha-2 adrenergic blockade with intra-arterial yohimbine. Leg blood flow was measured using 2D and Doppler ultrasound, and arterial blood pressure was determined directly. NP caused the expected vasoconstriction, and this response was significantly reduced (by 50-60%) when NP was repeated after yohimbine. These data indicate that alpha-2 adrenergic receptors contribute significantly to CBR-induced vasoconstriction in the human leg under resting conditions. PMID:18054844

Wray, D Walter; Raven, Peter B; Sander, Mikael

2008-02-29

349

Prostaglandin E2 EP1 receptor enhances TGF??1-induced mesangial cell injury.  

PubMed

Increasing evidence indicates that transforming growth factor-?1 (TGF-?1) is a pivotal mediator in the pathogenesis of renal fibrosis. Mesangial cells (MCs) are important for glomerular function under both physiological and pathological conditions. Studies have found that the expression level of prostaglandin E2 (PGE2) in MCs increases under high glucose conditions, that PGE2 affects the proliferation and hypertrophy of MCs mainly through the EP1 pathway, and that the proliferation of MCs and the accumulation of extracellular matrix are the main events leading to glomerular fibrosis. In this study, we investigated the effects and mechanisms of action of the EP1 receptor, which is induced by transforming growth factor (TGF)-?1, on the proliferation of mouse MCs, the accumulation of extracellular matrix and the expression of PGE2 synthase. Primary mouse glomerular MCs were isolated from EP1 receptor-deficient mice (EP1-/- mice, in which the EP1 receptor was knocked down) and wild-type (WT) mice (WT MCs). In our preliminary experiments, we found that cell proliferation, as well as the mRNA and protein expression of cyclin D1, proliferating cell nuclear antigen (PCNA), fibronectin (FN), collagen ? (Col?), membrane-associated PGE2 synthase-1 (mPGES-1) and cyclooxygenase-2 (COX-2) in the WT MCs were significantly increased following treatment with 10 ng/ml TGF-?1 for 24 h. Compared with the WT MCs, following the knockdown of the EP1 gene, the TGF-?1-induced MC injury was markedly suppressed. The aforementioned changes were notably enhanced following treatment with the EP1 agonist, 17-phenyl trinor PGE2 ethyl amide. Additionally, TGF-?1 induced extracellular signal-regulated kinase (ERK) phosphorylation. We found that the TGF-?1-induced ERK phosphorylation was alleviated by EP1 knockdown and promoted by EP1 expresion. These results suggest that the EP1 receptor plays a role in the proliferation of mouse MCs, in the accumulation of extracellular matrix and in the expression of mPGES-1 induced by TGF-?1. Its mechanisms of action are possibly related to the reinforcement of ERK phosphorylation. PMID:25352206

Chen, Xu; Jiang, Daishan; Wang, Jing; Chen, Xiaolan; Xu, Xiaolin; Xi, Peipei; Fan, Yaping; Zhang, Xiaoyan; Guan, Youfei

2015-01-01

350

Binding of beta-amyloid to the p75 neurotrophin receptor induces apoptosis. A possible mechanism for Alzheimer's disease.  

PubMed Central

Alzheimer's disease is a neurodegenerative disorder characterized by the extracellular deposition in the brain of aggregated beta-amyloid peptide, presumed to play a pathogenic role, and by preferential loss of neurons that express the 75-kD neurotrophin receptor (p75NTR). Using rat cortical neurons and NIH-3T3 cell line engineered to stably express p75NTR, we find that the beta-amyloid peptide specifically binds the p75NTR. Furthermore, 3T3 cells expressing p75NTR, but not wild-type control cells lacking the receptor, undergo apoptosis in the presence of aggregated beta-amyloid. Normal neural crest-derived melanocytes that express physiologic levels of p75NTR undergo apoptosis in the presence of aggregated beta-amyloid, but not in the presence of control peptide synthesized in reverse. These data imply that neuronal death in Alzheimer's disease is mediated, at least in part, by the interaction of beta-amyloid with p75NTR, and suggest new targets for therapeutic intervention. PMID:9410912

Yaar, M; Zhai, S; Pilch, P F; Doyle, S M; Eisenhauer, P B; Fine, R E; Gilchrest, B A

1997-01-01

351

Repeated potentiation of the metabotropic glutamate receptor 5 and the alpha 7 nicotinic acetylcholine receptor modulates behavioural and GABAergic deficits induced by early postnatal phencyclidine (PCP) treatment.  

PubMed

The underlying mechanism of the GABAergic deficits observed in schizophrenia has been proposed to involve NMDA receptor hypofunction. An emerging treatment strategy therefore aims at enhancing GABAergic signalling by increasing the excitatory transmission onto interneurons. We wanted to determine whether behavioural and GABAergic functional deficits induced by the NMDA receptor channel blocker, phencyclidine (PCP), could be reversed by repeated administration of two drugs known to enhance GABAergic transmission: the positive allosteric modulator (PAM) of the metabotropic glutamate receptor 5 (mGluR5), ADX47273, and the partial agonist of the ?7 nicotinic acetylcholine receptor (?7 nAChR), SSR180711. Adolescent rats (4-5 weeks) subjected to PCP treatment during the second postnatal week displayed a consistent deficit in prepulse inhibition (PPI), which was reversed by a one-week treatment with ADX47273 or SSR180711. We examined GABAergic transmission by whole cell patch-clamp recordings of miniature inhibitory postsynaptic currents (mIPSC) in pyramidal neurons in layer II/III of prefrontal cortex (PFC) and by activation of extrasynaptic ?-containing GABAA receptors by THIP. Following PCP treatment, pyramidal neurons displayed a reduced mIPSC frequency and up-regulation of extrasynaptic THIP-induced current. ADX47273 treatment restored this up-regulation of THIP-induced current. Reduced receptor function seems to be the underlying cause of the reported changes, since repeated treatment with ADX47273 and SSR180711 decreased the induction of spontaneous inhibitory current caused by acute and direct agonism of mGluR5s and ?7 nAChRs in slices. These results show that repeated administration of ADX47273 or SSR180711 reverses certain behavioural and functional deficits induced by PCP, likely through down-regulation or desensitisation of mGluR5s and ?7 nAChRs, respectively. PMID:23643744

Kjaerby, Celia; Bundgaard, Christoffer; Fejgin, Kim; Kristiansen, Uffe; Dalby, Nils Ole

2013-09-01

352

Defending plasma T3 is a biological priority.  

PubMed

Triiodothyronine (T3), the active form of thyroid hormone is produced predominantly outside the thyroid parenchyma secondary to peripheral tissue deiodination of thyroxine (T4), with <20% being secreted directly from the thyroid. In healthy individuals, plasma T3 is regulated by the negative feedback loop of the hypothalamus-pituitary-thyroid axis and by homoeostatic changes in deiodinase expression. Therefore, with the exception of a minimal circadian rhythmicity, serum T3 levels are stable over long periods of time. Studies in rodents indicate that different levels of genetic disruption of the feedback mechanism and deiodinase system are met with increase in serum T4 and thyroid-stimulating hormone (TSH) levels, while serum T3 levels remain stable. These findings have focused attention on serum T3 levels in patients with thyroid disease, with important clinical implications affecting therapeutic goals and choice of therapy for patients with hypothyroidism. Although monotherapy with levothyroxine is the standard of care for hypothyroidism, not all patients normalize serum T3 levels with many advocating for combination therapy with levothyroxine and liothyronine. The latter could be relevant for a significant number of patients that remain symptomatic on monotherapy with levothyroxine, despite normalization of serum TSH levels. PMID:25040645

Abdalla, Sherine M; Bianco, Antonio C

2014-11-01

353

Activation of Cannabinoid Type 2 Receptors Inhibits HIV-1 Envelope Glycoprotein gp120-Induced Synapse Loss  

PubMed Central

HIV-1 infection of the central nervous system is associated with dendritic and synaptic damage that correlates with cognitive decline in patients with HIV-1-associated dementia (HAD). HAD is due in part to the release of viral proteins from infected cells. Because cannabinoids modulate neurotoxic and inflammatory processes, we investigated their effects on changes in synaptic connections induced by the HIV-1 envelope glycoprotein gp120. Morphology and synapses between cultured hippocampal neurons were visualized by confocal imaging of neurons expressing DsRed2 and postsynaptic density protein 95 fused to green fluorescent protein (PSD95-GFP). Twenty-four-hour treatment with gp120 IIIB decreased the number of PSD95-GFP puncta by 37 ± 4%. The decrease was concentration-dependent (EC50 = 153 ± 50 pM). Synapse loss preceded cell death as defined by retention of DsRed2 fluorescence gp120 activated CXCR4 on microglia to evoke interleukin-1? (IL-1?) release. Pharmacological studies determined that sequential activation of CXCR4, the IL-1? receptor, and the N-methyl-d-aspartate receptor was required. Expression of alternative reading frame polypeptide, which inhibits the ubiquitin ligase murine double minute 2, protected synapses, implicating the ubiquitin-proteasome pathway. Cannabimimetic drugs are of particular relevance to HAD because of their clinical and illicit use in patients with AIDS. The cannabinoid receptor full agonist [(R)-(+)-[2,3-dihydro-5-methyl-3[(4-morpholinyl)methyl]pyrrolo[1,2,3-de]-1,4-benzoxazinyl]-(1-naphthalenyl) methanone mesylate salt] (Win55,212-2) inhibited gp120-induced IL-1? production and synapse in a manner reversed by a cannabinoid type 2 receptor antagonist. In contrast, Win55,212-2 did not inhibit synapse loss elicited by exposure to the HIV-1 protein Tat. These results indicate that cannabinoids prevent the impairment of network function produced by gp120 and, thus, might have therapeutic potential in HAD. PMID:21670103

Kim, Hee Jung; Shin, Angela H.

2011-01-01

354

P2X4 Receptor Regulates Alcohol-Induced Responses in Microglia.  

PubMed

Mounting evidence indicates that alcohol-induced neuropathology may result from multicellular responses in which microglia cells play a prominent role. Purinergic receptor signaling plays a key role in regulating microglial function and, more importantly, mediates alcohol-induced effects. Our findings demonstrate that alcohol increases expression of P2X4 receptor (P2X4R), which alters the function of microglia, including calcium mobilization, migration and phagocytosis. Our results show a significant up-regulation of P2X4 gene expression as analyzed by real-time qPCR (***p?receptor-dependent using the antagonist 5-BDBD, which reversed the effects as compared to alcohol alone (***p?receptor may play a role in modulating microglial function in the context of alcohol abuse. PMID:25135400

Gofman, Larisa; Cenna, Jonathan M; Potula, Raghava

2014-12-01

355

P2X7 Receptor Modulates Inflammatory and Functional Pulmonary Changes Induced by Silica.  

PubMed

Silicosis is an occupational lung disease, characterized by irreversible and progressive fibrosis. Silica exposure leads to intense lung inflammation, reactive oxygen production, and extracellular ATP (eATP) release by macrophages. The P2X7 purinergic receptor is thought to be an important immunomodulator that responds to eATP in sites of inflammation and tissue damage. The present study investigates the role of P2X7 receptor in a murine model of silicosis. To that end wild-type (C57BL/6) and P2X7 receptor knockout mice received intratracheal injection of saline or silica particles. After 14 days, changes in lung mechanics were determined by the end-inflation occlusion method. Bronchoalveolar lavage and flow cytometry analyzes were performed. Lungs were harvested for histological and immunochemistry analysis of fibers content, inflammatory infiltration, apoptosis, as well as cytokine and oxidative stress expression. Silica particle effects on lung alveolar macrophages and fibroblasts were also evaluated in cell line cultures. Phagocytosis assay was performed in peritoneal macrophages. Silica exposure increased lung mechanical parameters in wild-type but not in P2X7 knockout mice. Inflammatory cell infiltration and collagen deposition in lung parenchyma, apoptosis, TGF-? and NF-?B activation, as well as nitric oxide, reactive oxygen species (ROS) and IL-1? secretion were higher in wild-type than knockout silica-exposed mice. In vitro studies suggested that P2X7 receptor participates in silica particle phagocytosis, IL-1? secretion, as well as reactive oxygen species and nitric oxide production. In conclusion, our data showed a significant role for P2X7 receptor in silica-induced lung changes, modulating lung inflammatory, fibrotic, and functional changes. PMID:25310682

Monçăo-Ribeiro, Leonardo C; Faffe, Débora S; Santana, Patrícia T; Vieira, Flávia S; da Graça, Carolyne Lalucha A L; Marques-da-Silva, Camila; Machado, Mariana N; Caruso-Neves, Celso; Zin, Walter A; Borojevic, Radovan; Takiya, Christina M; Coutinho-Silva, Robson

2014-01-01

356

Histamine 3 receptor activation mediates inhibition of acid secretion during Helicobacter-induced gastritis  

PubMed Central

AIM: To test the hypothesis that histamine 3 receptor (H3R) activation during Helicobacter infection inhibits gastric acid secretion in vivo and in vitro. METHODS: Helicobacter felis (H. felis) infected and uninfected C57Bl/6 mice were infused with either PBS or the H3 receptor antagonist thioperamide (THIO) for 12 wk. After treatment, mice were analyzed for morphological changes and gastric acid content. Total RNA was prepared from the stomachs of each group and analyzed for changes in somatostatin and gastrin mRNA abundance by real time-polymerase chain reaction (RT-PCR). Location of H3 receptors in the stomach was analyzed by co-localization using antibodies specific for the H3 receptor and parietal cell marker H+, K+-ATPase ? subunit. RESULTS: Inflammation and parietal cell atrophy was observed after 12 wk of H. felis infection. Interestingly, treatment with the H3R antagonist thioperamide (THIO) prior to and during infection prevented H. felis-induced inflammation and atrophy. Compared to the uninfected controls, infected mice also had significantly decreased gastric acid. After eradication of H. felis with THIO treatment, gastric acidity was restored. Compared to the control mice, somatostatin mRNA abundance was decreased while gastrin gene expression was elevated during infection. Despite elevated gastric acid levels, after eradication of H. felis with THIO, somatostatin mRNA was elevated whereas gastrin mRNA was suppressed. Immunofluorescence revealed the presence of H3 receptors on the parietal cells, somatostatin-secreting D-cells as well as the inflammatory cells. CONCLUSION: This study shows that during H. felis infection, gastric acidity is suppressed as a consequence of an inhibitory effect on the parietal cell by H3R activation. The stimulation of gastric mucosal H3Rs increases gastrin expression and release by inhibiting release of somatostatin. PMID:21607157

Zavros, Yana; Mesiwala, Nisreen; Waghray, Meghna; Todisco, Andrea; Shulkes, Arthur; Merchant, Juanita L

2010-01-01

357

Novel Receptor-Based Countermeasures to Microgravity-Induced Bone Loss  

NASA Technical Reports Server (NTRS)

The biological actions mediated by the estrogen receptor (ER), vitamin D receptor (VDR) and Ca(sup 2+) (sub o) -sensing receptor (CaR) play key roles in the normal control of bone growth and skeletal turnover that is necessary for skeletal health. These receptors act by controlling the differentiation and/or function of osteoblasts and osteoclasts, and other cell types within the bone and bone marrow microenvironment. The appropriate use of selective ER modulators (SERMS) which target bone, vitamin D analogs that favor bone formation relative to resorption, and CaR agonists may both stimulate osteoblastogenesis and inhibit osteoclastogenesis and the function of mature osteoclasts, should make it possible to prevent the reduction in bone formation and increase in bone resorption that normally contribute to the bone loss induced by weightlessness. Indeed, there may be synergistic interactions among these receptors that enhance the actions of any one used alone. Therefore, we proposed to: 1) assess the in vitro ability of novel ER, VDR and CaR agonists, alone or in combination, to modulate osteoblastogenesis and mature osteoblast function under conditions of 1g and simulated microgravity; 2) assess the in vitro ability of novel ER, VDR and CaR agonists, alone or in combination, to modulate osteoclastogenesis and bone resorption under conditions of lg and simulated microgravity; and 3) carry out baseline studies on the skeletal localization of the CaR in normal rat bone as well as the in vivo actions of our novel ER- and VDR-based therapeutics in the rat in preparation for their use, alone or in combination, in well-established ground-based models of microgravity and eventually in space flight.

OMalley, Bert W.

1999-01-01

358

P2X7 Receptor Modulates Inflammatory and Functional Pulmonary Changes Induced by Silica  

PubMed Central

Silicosis is an occupational lung disease, characterized by irreversible and progressive fibrosis. Silica exposure leads to intense lung inflammation, reactive oxygen production, and extracellular ATP (eATP) release by macrophages. The P2X7 purinergic receptor is thought to be an important immunomodulator that responds to eATP in sites of inflammation and tissue damage. The present study investigates the role of P2X7 receptor in a murine model of silicosis. To that end wild-type (C57BL/6) and P2X7 receptor knockout mice received intratracheal injection of saline or silica particles. After 14 days, changes in lung mechanics were determined by the end-inflation occlusion method. Bronchoalveolar lavage and flow cytometry analyzes were performed. Lungs were harvested for histological and immunochemistry analysis of fibers content, inflammatory infiltration, apoptosis, as well as cytokine and oxidative stress expression. Silica particle effects on lung alveolar macrophages and fibroblasts were also evaluated in cell line cultures. Phagocytosis assay was performed in peritoneal macrophages. Silica exposure increased lung mechanical parameters in wild-type but not in P2X7 knockout mice. Inflammatory cell infiltration and collagen deposition in lung parenchyma, apoptosis, TGF-? and NF-?B activation, as well as nitric oxide, reactive oxygen species (ROS) and IL-1? secretion were higher in wild-type than knockout silica-exposed mice. In vitro studies suggested that P2X7 receptor participates in silica particle phagocytosis, IL-1? secretion, as well as reactive oxygen species and nitric oxide production. In conclusion, our data showed a significant role for P2X7 receptor in silica-induced lung changes, modulating lung inflammatory, fibrotic, and functional changes. PMID:25310682

Santana, Patricia T.; Vieira, Flavia S.; da Graca, Carolyne Lalucha A. L.; M