Exosome uptake depends on ERK1/2-heat shock protein 27 signaling and lipid Raft-mediated endocytosis negatively regulated by caveolin-1.

PubMed

Svensson, Katrin J; Christianson, Helena C; Wittrup, Anders; Bourseau-Guilmain, Erika; Lindqvist, Eva; Svensson, Lena M; Mörgelin, Matthias; Belting, Mattias

2013-06-14

The role of exosomes in cancer can be inferred from the observation that they transfer tumor cell derived genetic material and signaling proteins, resulting in e.g. increased tumor angiogenesis and metastasis. However, the membrane transport mechanisms and the signaling events involved in the uptake of these virus-like particles remain ill-defined. We now report that internalization of exosomes derived from glioblastoma (GBM) cells involves nonclassical, lipid raft-dependent endocytosis. Importantly, we show that the lipid raft-associated protein caveolin-1 (CAV1), in analogy with its previously described role in virus uptake, negatively regulates the uptake of exosomes. We find that exosomes induce the phosphorylation of several downstream targets known to associate with lipid rafts as signaling and sorting platforms, such as extracellular signal-regulated kinase-1/2 (ERK1/2) and heat shock protein 27 (HSP27). Interestingly, exosome uptake appears dependent on unperturbed ERK1/2-HSP27 signaling, and ERK1/2 phosphorylation is under negative influence by CAV1 during internalization of exosomes. These findings significantly advance our general understanding of exosome-mediated uptake and offer potential strategies for how this pathway may be targeted through modulation of CAV1 expression and ERK1/2 signaling.

Mesothelial- and epithelial-derived FGF9 have distinct functions in the regulation of lung development

PubMed Central

Yin, Yongjun; Wang, Fen; Ornitz, David M.

2011-01-01

Fibroblast growth factor (FGF) 9 is a secreted signaling molecule that is expressed in lung mesothelium and epithelium and is required for lung development. Embryos lacking FGF9 show mesenchymal hypoplasia, decreased epithelial branching and, by the end of gestation, hypoplastic lungs that cannot support life. Mesenchymal FGF signaling interacts with β-catenin-mediated WNT signaling in a feed-forward loop that functions to sustain mesenchymal FGF responsiveness and mesenchymal WNT/β-catenin signaling. During pseudoglandular stages of lung development, Wnt2a and Wnt7b are the canonical WNT ligands that activate mesenchymal WNT/β-catenin signaling, whereas FGF9 is the only known ligand that signals to mesenchymal FGF receptors (FGFRs). Here, we demonstrate that mesothelial- and epithelial-derived FGF9, mesenchymal Wnt2a and epithelial Wnt7b have unique functions in lung development in mouse. Mesothelial FGF9 and mesenchymal WNT2A are principally responsible for maintaining mesenchymal FGF-WNT/β-catenin signaling, whereas epithelial FGF9 primarily affects epithelial branching. We show that FGF signaling is primarily responsible for regulating mesenchymal proliferation, whereas β-catenin signaling is a required permissive factor for mesenchymal FGF signaling. PMID:21750028

Dynamic and diverse sugar signaling

PubMed Central

Li, Lei; Sheen, Jen

2016-01-01

Sugars fuel life and exert numerous regulatory actions that are fundamental to all life forms. There are two principal mechanisms underlie sugar “perception and signal transduction” in biological systems. Direct sensing and signaling is triggered via sugar-binding sensors with a broad range of affinity and specificity, whereas sugar-derived bioenergetic molecules and metabolites modulate signaling proteins and indirectly relay sugar signals. This review discusses the emerging sugar signals and potential sugar sensors discovered in plant systems. The findings leading to informative understanding of physiological regulation by sugars are considered and assessed. Comparative transcriptome analyses highlight the primary and dynamic sugar responses and reveal the convergent and specific regulators of key biological processes in the sugar-signaling network. PMID:27423125

Skeletal muscle-derived progenitors capable of differentiating into cardiomyocytes proliferate through myostatin-independent TGF-{beta} family signaling

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

Nomura, Tetsuya; Department of Cardiovascular Medicine, Kyoto Prefectural University of Medicine, Kyoto 602-8566; Ueyama, Tomomi

2008-01-25

The existence of skeletal muscle-derived stem cells (MDSCs) has been suggested in mammals; however, the signaling pathways controlling MDSC proliferation remain largely unknown. Here we report the isolation of myosphere-derived progenitor cells (MDPCs) that can give rise to beating cardiomyocytes from adult skeletal muscle. We identified that follistatin, an antagonist of TGF-{beta} family members, was predominantly expressed in MDPCs, whereas myostatin was mainly expressed in myogenic cells and mature skeletal muscle. Although follistatin enhanced the replicative growth of MDPCs through Smad2/3 inactivation and cell cycle progression, disruption of myostatin did not increase the MDPC proliferation. By contrast, inhibition of activinmore » A (ActA) or growth differentiation factor 11 (GDF11) signaling dramatically increased MDPC proliferation via down-regulation of p21 and increases in the levels of cdk2/4 and cyclin D1. Thus, follistatin may be an effective progenitor-enhancing agent neutralizing ActA and GDF11 signaling to regulate the growth of MDPCs in skeletal muscle.« less

ROS/redox signaling regulates bone turnover in an age-specific manner in female mice

USDA-ARS?s Scientific Manuscript database

In bone, oxidant signaling through NADPH oxidase (NOX)-derived reactive oxygen species (ROS) superoxide and/or hydrogen peroxide appears to be an important stimulus for osteoclast differentiation and activity. ROS signaling has been suggested to increase RANKL mRNA and protein expression, thus enha...

Sex and Stress Hormone Influences on the Expression and Activity of Brain-Derived Neurotrophic Factor

PubMed Central

Carbone, David L.; Handa, Robert J.

2012-01-01

The neurotrophin, brain-derived neurotrophic factor (BDNF), is recognized as a key component in the regulation of central nervous system ontogeny, homeostasis and adult neuroplasticity. The importance of BDNF in central nervous system development and function is well documented by numerous reports from animal studies linking abnormal BDNF signaling to metabolic disturbances and anxiety or depressive-like behavior. Despite the diverse roles for BDNF in nearly all aspects of central nervous system physiology, the regulation of BDNF expression, as well as our understanding of the signaling mechanisms associated with this neurotrophin, remains incomplete. However, links between sex hormones such as estradiol and testosterone, as well as endogenous and synthetic glucocorticoids, have emerged as important mediators of BDNF expression and function. Examples of such regulation include brain region-specific induction of Bdnf mRNA in response to estradiol. Additional studies have also documented regulation of the expression of the high-affinity BDNF receptor TrkB by estradiol, thus implicating sex steroids not only in the regulation of BDNF expression, but on mechanisms of signaling associated with it. In addition to gonadal steroids, further evidence also suggests functional interaction between BDNF and glucocorticoids, such as in the regulation of corticotrophin-releasing hormone and other important neuropeptides. In this review, we provide an overview of the roles played by selected sex or stress hormones in the regulation of BDNF expression and signaling in the central nervous system PMID:23211562

Indian hedgehog signaling from endothelial cells is required for sclera and retinal pigment epithelium development in the mouse eye.

PubMed

Dakubo, Gabriel D; Mazerolle, Chantal; Furimsky, Marosh; Yu, Chuan; St-Jacques, Benoit; McMahon, Andrew P; Wallace, Valerie A

2008-08-01

The development of extraocular orbital structures, in particular the choroid and sclera, is regulated by a complex series of interactions between neuroectoderm, neural crest and mesoderm derivatives, although in many instances the signals that mediate these interactions are not known. In this study we have investigated the function of Indian hedgehog (Ihh) in the developing mammalian eye. We show that Ihh is expressed in a population of non-pigmented cells located in the developing choroid adjacent to the RPE. The analysis of Hh mutant mice demonstrates that the RPE and developing scleral mesenchyme are direct targets of Ihh signaling and that Ihh is required for the normal pigmentation pattern of the RPE and the condensation of mesenchymal cells to form the sclera. Our findings also indicate that Ihh signals indirectly to promote proliferation and photoreceptor specification in the neural retina. This study identifies Ihh as a novel choroid-derived signal that regulates RPE, sclera and neural retina development.

Riboswitches for the alarmone ppGpp expand the collection of RNA-based signaling systems

PubMed Central

Sudarsan, Narasimhan; Breaker, Ronald R.

2018-01-01

Riboswitches are noncoding portions of certain mRNAs that bind metabolite, coenzyme, signaling molecule, or inorganic ion ligands and regulate gene expression. Most known riboswitches sense derivatives of RNA monomers. This bias in ligand chemical composition is consistent with the hypothesis that widespread riboswitch classes first emerged during the RNA World, which is proposed to have existed before proteins were present. Here we report the discovery and biochemical validation of a natural riboswitch class that selectively binds guanosine tetraphosphate (ppGpp), a widespread signaling molecule and bacterial “alarmone” derived from the ribonucleotide GTP. Riboswitches for ppGpp are predicted to regulate genes involved in branched-chain amino acid biosynthesis and transport, as well as other gene classes that previously had not been implicated to be part of its signaling network. This newfound riboswitch–alarmone partnership supports the hypothesis that prominent RNA World signaling pathways have been retained by modern cells to control key biological processes. PMID:29784782

Riboswitches for the alarmone ppGpp expand the collection of RNA-based signaling systems.

PubMed

Sherlock, Madeline E; Sudarsan, Narasimhan; Breaker, Ronald R

2018-06-05

Riboswitches are noncoding portions of certain mRNAs that bind metabolite, coenzyme, signaling molecule, or inorganic ion ligands and regulate gene expression. Most known riboswitches sense derivatives of RNA monomers. This bias in ligand chemical composition is consistent with the hypothesis that widespread riboswitch classes first emerged during the RNA World, which is proposed to have existed before proteins were present. Here we report the discovery and biochemical validation of a natural riboswitch class that selectively binds guanosine tetraphosphate (ppGpp), a widespread signaling molecule and bacterial "alarmone" derived from the ribonucleotide GTP. Riboswitches for ppGpp are predicted to regulate genes involved in branched-chain amino acid biosynthesis and transport, as well as other gene classes that previously had not been implicated to be part of its signaling network. This newfound riboswitch-alarmone partnership supports the hypothesis that prominent RNA World signaling pathways have been retained by modern cells to control key biological processes. Copyright © 2018 the Author(s). Published by PNAS.

PKC signaling is involved in the regulation of progranulin (acrogranin/PC-cell-derived growth factor/granulin-epithelin precursor) protein expression in human ovarian cancer cell lines.

PubMed

Diaz-Cueto, Laura; Arechavaleta-Velasco, Fabian; Diaz-Arizaga, Adriana; Dominguez-Lopez, Pablo; Robles-Flores, Martha

2012-07-01

Overexpression of progranulin (also named acrogranin, PC-cell-derived growth factor, or granulin-epithelin precursor) is associated with ovarian cancer, specifically with cell proliferation, malignancy, chemoresistance, and shortened overall survival. The objective of the current study is to identify the signaling pathways involved in the regulation of progranulin expression in ovarian cancer cell lines. We studied the relation of protein kinase C (PKC), phosphatidylinositol 3-kinase, protein kinase A, P38, extracellular signal-regulated kinase, and Akt pathways on the modulation of progranulin expression levels in NIH-OVCAR-3 and SK-OV-3 ovarian cancer cell lines. The different pathways were examined using pharmacological inhibitors (calphostin C, LY294002, H89, SB203580, PD98059, and Akt Inhibitor), and mRNA and protein progranulin expression were analyzed by reverse transcriptase polymerase chain reaction and Western blot techniques, respectively. Inhibition of PKC signal transduction pathway by calphostin C decreased in a dose-dependent manner protein but not mRNA levels of progranulin in both ovarian cancer cell lines. LY294002 but not wortmannin, which are phosphatidylinositol 3-kinase inhibitors, also diminished the expression of progranulin in both cell lines. In addition, LY294002 treatment produced a significant reduction in cell viability. Inhibition of protein kinase A, P38, extracellular signal-regulated kinase, and Akt did not affect progranulin protein expression. These results suggest that the PKC signaling is involved in the regulation of progranulin protein expression in 2 different ovarian cancer cell lines. Inhibiting these intracellular signal transduction pathways may provide a future therapeutic target for hindering the cellular proliferation and invasion in ovarian cancer produced by progranulin.

Phospholipase D and phosphatidic acid in plant defence response: from protein-protein and lipid-protein interactions to hormone signalling.

PubMed

Zhao, Jian

2015-04-01

Phospholipase Ds (PLDs) and PLD-derived phosphatidic acids (PAs) play vital roles in plant hormonal and environmental responses and various cellular dynamics. Recent studies have further expanded the functions of PLDs and PAs into plant-microbe interaction. The molecular diversities and redundant functions make PLD-PA an important signalling complex regulating lipid metabolism, cytoskeleton dynamics, vesicle trafficking, and hormonal signalling in plant defence through protein-protein and protein-lipid interactions or hormone signalling. Different PLD-PA signalling complexes and their targets have emerged as fast-growing research topics for understanding their numerous but not yet established roles in modifying pathogen perception, signal transduction, and downstream defence responses. Meanwhile, advanced lipidomics tools have allowed researchers to reveal further the mechanisms of PLD-PA signalling complexes in regulating lipid metabolism and signalling, and their impacts on jasmonic acid/oxylipins, salicylic acid, and other hormone signalling pathways that essentially mediate plant defence responses. This review attempts to summarize the progress made in spatial and temporal PLD/PA signalling as well as PLD/PA-mediated modification of plant defence. It presents an in-depth discussion on the functions and potential mechanisms of PLD-PA complexes in regulating actin filament/microtubule cytoskeleton, vesicle trafficking, and hormonal signalling, and in influencing lipid metabolism-derived metabolites as critical signalling components in plant defence responses. The discussion puts PLD-PA in a broader context in order to guide future research. © The Author 2015. Published by Oxford University Press on behalf of the Society for Experimental Biology. All rights reserved. For permissions, please email: journals.permissions@oup.com.

Pharmacologic inhibition of MEK signaling prevents growth of canine hemangiosarcoma.

PubMed

Andersen, Nicholas J; Nickoloff, Brian J; Dykema, Karl J; Boguslawski, Elissa A; Krivochenitser, Roman I; Froman, Roe E; Dawes, Michelle J; Baker, Laurence H; Thomas, Dafydd G; Kamstock, Debra A; Kitchell, Barbara E; Furge, Kyle A; Duesbery, Nicholas S

2013-09-01

Angiosarcoma is a rare neoplasm of endothelial origin that has limited treatment options and poor five-year survival. As a model for human angiosarcoma, we studied primary cells and tumorgrafts derived from canine hemangiosarcoma (HSA), which is also an endothelial malignancy with similar presentation and histology. Primary cells isolated from HSA showed constitutive extracellular signal-regulated kinase (ERK) activation. The mitogen-activated protein/extracellular signal-regulated kinase (MEK) inhibitor CI-1040 reduced ERK activation and the viability of primary cells derived from visceral, cutaneous, and cardiac HSA in vitro. HSA-derived primary cells were also sensitive to sorafenib, an inhibitor of B-Raf and multireceptor tyrosine kinases. In vivo, CI-1040 or PD0325901 decreased the growth of cutaneous cell-derived xenografts and cardiac-derived tumorgrafts. Sorafenib decreased tumor size in both in vivo models, although cardiac tumorgrafts were more sensitive. In human angiosarcoma, we noted that 50% of tumors stained positively for phosphorylated ERK1/2 and that the expression of several MEK-responsive transcription factors was upregulated. Our data showed that MEK signaling is essential for the growth of HSA in vitro and in vivo and provided evidence that the same pathways are activated in human angiosarcoma. This indicates that MEK inhibitors may form part of an effective therapeutic strategy for the treatment of canine HSA or human angiosarcoma, and it highlights the use of spontaneous canine cancers as a model of human disease.

EMMPRIN regulates tumor growth and metastasis by recruiting bone marrow-derived cells through paracrine signaling of SDF-1 and VEGF.

PubMed

Chen, Yanke; Gou, Xingchun; Kong, Derek Kai; Wang, Xiaofei; Wang, Jianhui; Chen, Zeming; Huang, Chen; Zhou, Jiangbing

2015-10-20

EMMPRIN, a cell adhesion molecule highly expressed in a variety of tumors, is associated with poor prognosis in cancer patients. Mechanistically, EMMPRIN has been characterized to contribute to tumor development and progression by controlling the expression of MMPs and VEGF. In the present study, by using fluorescently labeled bone marrow-derived cells (BMDCs), we found that the down-regulation of EMMPRIN expression in cancer cells reduces tumor growth and metastasis, and is associated with the reduced recruitment of BMDCs. Further protein profiling studies suggest that EMMPRIN controls BMDC recruitment through regulating the secretion of soluble factors, notably, VEGF and SDF-1. We demonstrate that the expression and secretion of SDF-1 in tumor cells are regulated by EMMPRIN. This study reveals a novel mechanism by which EMMPRIN promotes tumor growth and metastasis by recruitment of BMDCs through controlling secretion and paracrine signaling of SDF-1 and VEGF.

Cannabinoid receptor signaling in progenitor/stem cell proliferation and differentiation.

PubMed

Galve-Roperh, Ismael; Chiurchiù, Valerio; Díaz-Alonso, Javier; Bari, Monica; Guzmán, Manuel; Maccarrone, Mauro

2013-10-01

Cannabinoids, the active components of cannabis (Cannabis sativa) extracts, have attracted the attention of human civilizations for centuries, much earlier than the discovery and characterization of their substrate of action, the endocannabinoid system (ECS). The latter is an ensemble of endogenous lipids, their receptors [in particular type-1 (CB1) and type-2 (CB2) cannabinoid receptors] and metabolic enzymes. Cannabinoid signaling regulates cell proliferation, differentiation and survival, with different outcomes depending on the molecular targets and cellular context involved. Cannabinoid receptors are expressed and functional from the very early developmental stages, when they regulate embryonic and trophoblast stem cell survival and differentiation, and thus may affect the formation of manifold adult specialized tissues derived from the three different germ layers (ectoderm, mesoderm and endoderm). In the ectoderm-derived nervous system, both CB1 and CB2 receptors are present in neural progenitor/stem cells and control their self-renewal, proliferation and differentiation. CB1 and CB2 show opposite patterns of expression, the former increasing and the latter decreasing along neuronal differentiation. Recently, endocannabinoid (eCB) signaling has also been shown to regulate proliferation and differentiation of mesoderm-derived hematopoietic and mesenchymal stem cells, with a key role in determining the formation of several cell types in peripheral tissues, including blood cells, adipocytes, osteoblasts/osteoclasts and epithelial cells. Here, we will review these new findings, which unveil the involvement of eCB signaling in the regulation of progenitor/stem cell fate in the nervous system and in the periphery. The developmental regulation of cannabinoid receptor expression and cellular/subcellular localization, together with their role in progenitor/stem cell biology, may have important implications in human health and disease. Copyright © 2013 Elsevier Ltd. All rights reserved.

Shoot-derived abscisic acid promotes root growth.

PubMed

McAdam, Scott A M; Brodribb, Timothy J; Ross, John J

2016-03-01

The phytohormone abscisic acid (ABA) plays a major role in regulating root growth. Most work to date has investigated the influence of root-sourced ABA on root growth during water stress. Here, we tested whether foliage-derived ABA could be transported to the roots, and whether this foliage-derived ABA had an influence on root growth under well-watered conditions. Using both application studies of deuterium-labelled ABA and reciprocal grafting between wild-type and ABA-biosynthetic mutant plants, we show that both ABA levels in the roots and root growth in representative angiosperms are controlled by ABA synthesized in the leaves rather than sourced from the roots. Foliage-derived ABA was found to promote root growth relative to shoot growth but to inhibit the development of lateral roots. Increased root auxin (IAA) levels in plants with ABA-deficient scions suggest that foliage-derived ABA inhibits root growth through the root growth-inhibitor IAA. These results highlight the physiological and morphological importance, beyond the control of stomata, of foliage-derived ABA. The use of foliar ABA as a signal for root growth has important implications for regulating root to shoot growth under normal conditions and suggests that leaf rather than root hydration is the main signal for regulating plant responses to moisture. © 2015 John Wiley & Sons Ltd.

BMP regulates regional gene expression in the dorsal otocyst through canonical and non-canonical intracellular pathways

PubMed Central

2016-01-01

The inner ear consists of two otocyst-derived, structurally and functionally distinct components: the dorsal vestibular and ventral auditory compartments. BMP signaling is required to form the vestibular compartment, but how it complements other required signaling molecules and acts intracellularly is unknown. Using spatially and temporally controlled delivery of signaling pathway regulators to developing chick otocysts, we show that BMP signaling regulates the expression of Dlx5 and Hmx3, both of which encode transcription factors essential for vestibular formation. However, although BMP regulates Dlx5 through the canonical SMAD pathway, surprisingly, it regulates Hmx3 through a non-canonical pathway involving both an increase in cAMP-dependent protein kinase A activity and the GLI3R to GLI3A ratio. Thus, both canonical and non-canonical BMP signaling establish the precise spatiotemporal expression of Dlx5 and Hmx3 during dorsal vestibular development. The identification of the non-canonical pathway suggests an intersection point between BMP and SHH signaling, which is required for ventral auditory development. PMID:27151948

Lysophosphatidic acid acts as a nutrient-derived developmental cue to regulate early hematopoiesis

PubMed Central

Li, Haisen; Yue, Rui; Wei, Bin; Gao, Ge; Du, Jiulin; Pei, Gang

2014-01-01

Primitive hematopoiesis occurs in the yolk sac blood islands during vertebrate embryogenesis, where abundant phosphatidylcholines (PC) are available as important nutrients for the developing embryo. However, whether these phospholipids also generate developmental cues to promote hematopoiesis is largely unknown. Here, we show that lysophosphatidic acid (LPA), a signaling molecule derived from PC, regulated hemangioblast formation and primitive hematopoiesis. Pharmacological and genetic blockage of LPA receptor 1 (LPAR1) or autotoxin (ATX), a secretory lysophospholipase that catalyzes LPA production, inhibited hematopoietic differentiation of mouse embryonic stem cells and impaired the formation of hemangioblasts. Mechanistic experiments revealed that the regulatory effect of ATX-LPA signaling was mediated by PI3K/Akt-Smad pathway. Furthermore, during in vivo embryogenesis in zebrafish, LPA functioned as a developmental cue for hemangioblast formation and primitive hematopoiesis. Taken together, we identified LPA as an important nutrient-derived developmental cue for primitive hematopoiesis as well as a novel mechanism of hemangioblast regulation. PMID:24829209

Lysophosphatidic acid acts as a nutrient-derived developmental cue to regulate early hematopoiesis.

PubMed

Li, Haisen; Yue, Rui; Wei, Bin; Gao, Ge; Du, Jiulin; Pei, Gang

2014-06-17

Primitive hematopoiesis occurs in the yolk sac blood islands during vertebrate embryogenesis, where abundant phosphatidylcholines (PC) are available as important nutrients for the developing embryo. However, whether these phospholipids also generate developmental cues to promote hematopoiesis is largely unknown. Here, we show that lysophosphatidic acid (LPA), a signaling molecule derived from PC, regulated hemangioblast formation and primitive hematopoiesis. Pharmacological and genetic blockage of LPA receptor 1 (LPAR1) or autotoxin (ATX), a secretory lysophospholipase that catalyzes LPA production, inhibited hematopoietic differentiation of mouse embryonic stem cells and impaired the formation of hemangioblasts. Mechanistic experiments revealed that the regulatory effect of ATX-LPA signaling was mediated by PI3K/Akt-Smad pathway. Furthermore, during in vivo embryogenesis in zebrafish, LPA functioned as a developmental cue for hemangioblast formation and primitive hematopoiesis. Taken together, we identified LPA as an important nutrient-derived developmental cue for primitive hematopoiesis as well as a novel mechanism of hemangioblast regulation. © 2014 The Authors.

CD147 induces up-regulation of vascular endothelial growth factor in U937-derived foam cells through PI3K/AKT pathway.

PubMed

Zong, JiaXin; Li, YunTian; Du, DaYong; Liu, Yang; Yin, YongJun

2016-11-01

Intraplaque angiogenesis has been recognized as an important risk factor for the rupture of advanced atherosclerotic plaques in recent years. CD147, also called Extracellular Matrix Metalloproteinase Inducer, has been found the ability to promote angiogenesis in many pathological conditions such as cancer diseases and rheumatoid arthritis via the up-regulation of vascular endothelial growth factor (VEGF), a critical mediator of angiogenesis. We investigated whether CD147 would also induce the up-regulation of VEGF in the foam cells formation process and explored the probable signaling pathway. The results showed the expression of CD147 and VEGF was significantly higher in U937-derived foam cells. After CD147 stealth siRNA transfection treatment, the production of VEGF was reduced depended on the inhibition efficiency of CD147 siRNAs.The special signaling pathway inhibitors LY294002, SP600125, SB203580 and U0126 were added to cultures respectively and the results showed LY294002 dose-dependently inhibited the expression of VEGF. The reduction of phospho-Akt was observed in both LY294002 and siRNA groups, suggested that the phosphatidylinositol 3-kinase/Akt pathway may be the probable signaling pathway underlying CD147 induced up-regulation of VEGF in U937-derived foam cells. Copyright © 2016 Elsevier Inc. All rights reserved.

Exosomes derived from human macrophages suppress endothelial cell migration by controlling integrin trafficking.

PubMed

Lee, Hee Doo; Kim, Yeon Hyang; Kim, Doo-Sik

2014-04-01

Integrin trafficking, including internalization, recycling, and lysosomal degradation, is crucial for the regulation of cellular functions. Exosomes, nano-sized extracellular vesicles, are believed to play important roles in intercellular communications. This study demonstrates that exosomes released from human macrophages negatively regulate endothelial cell migration through control of integrin trafficking. Macrophage-derived exosomes promote internalization of integrin β1 in primary HUVECs. The internalized integrin β1 persistently accumulates in the perinuclear region and is not recycled back to the plasma membrane. Experimental results indicate that macrophage-derived exosomes stimulate trafficking of internalized integrin β1 to lysosomal compartments with a corresponding decrease in the integrin destined for recycling endosomes, resulting in proteolytic degradation of the integrin. Moreover, ubiquitination of HUVEC integrin β1 is enhanced by the exosomes, and exosome-mediated integrin degradation is blocked by bafilomycin A, a lysosomal degradation inhibitor. Macrophage-derived exosomes were also shown to effectively suppress collagen-induced activation of the mitogen-activated protein kinase/extracellular signal-regulated kinase signaling pathway and HUVEC migration, which are both dependent on integrin β1. These observations provide new insight into the functional significance of exosomes in the regulation of integrin trafficking. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Canonical Wnt signaling in megakaryocytes regulates proplatelet formation

PubMed Central

Macaulay, Iain C.; Thon, Jonathan N.; Tijssen, Marloes R.; Steele, Brian M.; MacDonald, Bryan T.; Meade, Gerardene; Burns, Philippa; Rendon, Augusto; Salunkhe, Vishal; Murphy, Ronan P.; Bennett, Cavan; Watkins, Nicholas A.; He, Xi; Fitzgerald, Desmond J.; Italiano, Joseph E.

2013-01-01

Wnt signaling is involved in numerous aspects of vertebrate development and homeostasis, including the formation and function of blood cells. Here, we show that canonical and noncanonical Wnt signaling pathways are present and functional in megakaryocytes (MKs), with several Wnt effectors displaying MK-restricted expression. Using the CHRF288-11 cell line as a model for human MKs, the canonical Wnt3a signal was found to induce a time and dose-dependent increase in β-catenin expression. β-catenin accumulation was inhibited by the canonical antagonist dickkopf-1 (DKK1) and by the noncanonical agonist Wnt5a. Whole genome expression analysis demonstrated that Wnt3a and Wnt5a regulated distinct patterns of gene expression in MKs, and revealed a further interplay between canonical and noncanonical Wnt pathways. Fetal liver cells derived from low-density-lipoprotein receptor-related protein 6-deficient mice (LRP6−/−), generated dramatically reduced numbers of MKs in culture of lower ploidy (2N and 4N) than wild-type controls, implicating LRP6-dependent Wnt signaling in MK proliferation and maturation. Finally, in wild-type mature murine fetal liver-derived MKs, Wnt3a potently induced proplatelet formation, an effect that could be completely abrogated by DKK1. These data identify novel extrinsic regulators of proplatelet formation, and reveal a profound role for Wnt signaling in platelet production. PMID:23160460

Modulation of occluding junctions alters the hematopoietic niche to trigger immune activation

PubMed Central

Khadilkar, Rohan J; Vogl, Wayne; Goodwin, Katharine

2017-01-01

Stem cells are regulated by signals from their microenvironment, or niche. During Drosophila hematopoiesis, a niche regulates prohemocytes to control hemocyte production. Immune challenges activate cell-signalling to initiate the cellular and innate immune response. Specifically, certain immune challenges stimulate the niche to produce signals that induce prohemocyte differentiation. However, the mechanisms that promote prohemocyte differentiation subsequent to immune challenges are poorly understood. Here we show that bacterial infection induces the cellular immune response by modulating occluding-junctions at the hematopoietic niche. Occluding-junctions form a permeability barrier that regulates the accessibility of prohemocytes to niche derived signals. The immune response triggered by infection causes barrier breakdown, altering the prohemocyte microenvironment to induce immune cell production. Moreover, genetically induced barrier ablation provides protection against infection by activating the immune response. Our results reveal a novel role for occluding-junctions in regulating niche-hematopoietic progenitor signalling and link this mechanism to immune cell production following infection. PMID:28841136

Anxiety, Depression, and the Microbiome: A Role for Gut Peptides.

PubMed

Lach, Gilliard; Schellekens, Harriet; Dinan, Timothy G; Cryan, John F

2018-01-01

The complex bidirectional communication between the gut and the brain is finely orchestrated by different systems, including the endocrine, immune, autonomic, and enteric nervous systems. Moreover, increasing evidence supports the role of the microbiome and microbiota-derived molecules in regulating such interactions; however, the mechanisms underpinning such effects are only beginning to be resolved. Microbiota-gut peptide interactions are poised to be of great significance in the regulation of gut-brain signaling. Given the emerging role of the gut-brain axis in a variety of brain disorders, such as anxiety and depression, it is important to understand the contribution of bidirectional interactions between peptide hormones released from the gut and intestinal bacteria in the context of this axis. Indeed, the gastrointestinal tract is the largest endocrine organ in mammals, secreting dozens of different signaling molecules, including peptides. Gut peptides in the systemic circulation can bind cognate receptors on immune cells and vagus nerve terminals thereby enabling indirect gut-brain communication. Gut peptide concentrations are not only modulated by enteric microbiota signals, but also vary according to the composition of the intestinal microbiota. In this review, we will discuss the gut microbiota as a regulator of anxiety and depression, and explore the role of gut-derived peptides as signaling molecules in microbiome-gut-brain communication. Here, we summarize the potential interactions of the microbiota with gut hormones and endocrine peptides, including neuropeptide Y, peptide YY, pancreatic polypeptide, cholecystokinin, glucagon-like peptide, corticotropin-releasing factor, oxytocin, and ghrelin in microbiome-to-brain signaling. Together, gut peptides are important regulators of microbiota-gut-brain signaling in health and stress-related psychiatric illnesses.

Direct Interaction between Scaffolding Proteins RACK1 and 14-3-3ζ Regulates Brain-derived Neurotrophic Factor (BDNF) Transcription*

PubMed Central

Neasta, Jérémie; Kiely, Patrick A.; He, Dao-Yao; Adams, David R.; O'Connor, Rosemary; Ron, Dorit

2012-01-01

RACK1 is a scaffolding protein that spatially and temporally regulates numerous signaling cascades. We previously found that activation of the cAMP signaling pathway induces the translocation of RACK1 to the nucleus. We further showed that nuclear RACK1 is required to promote the transcription of the brain-derived neurotrophic factor (BDNF). Here, we set out to elucidate the mechanism underlying cAMP-dependent RACK1 nuclear translocation and BDNF transcription. We identified the scaffolding protein 14-3-3ζ as a direct binding partner of RACK1. Moreover, we found that 14-3-3ζ was necessary for the cAMP-dependent translocation of RACK1 to the nucleus. We further observed that the disruption of RACK1/14-3-3ζ interaction with a peptide derived from the RACK1/14-3-3ζ binding site or shRNA-mediated 14-3-3ζ knockdown inhibited cAMP induction of BDNF transcription. Together, these data reveal that the function of nuclear RACK1 is mediated through its interaction with 14-3-3ζ. As RACK1 and 14-3-3ζ are two multifunctional scaffolding proteins that coordinate a wide variety of signaling events, their interaction is likely to regulate other essential cellular functions. PMID:22069327

Mesenchymal stem cells induce dermal fibroblast responses to injury

PubMed Central

Smith, Andria N.; Willis, Elise; Chan, Vincent T.; Muffley, Lara A.; Isik, F. Frank; Gibran, Nicole S.; Hocking, Anne M.

2009-01-01

Although bone marrow-derived mesenchymal stem cells have been shown to promote repair when applied to cutaneous wounds, the mechanism for this response remains to be determined. The aim of this study was to determine the effects of paracrine signaling from mesenchymal stem cells on dermal fibroblast responses to injury including proliferation, migration and expression of genes important in wound repair. Dermal fibroblasts were co-cultured with bone marrow-derived mesenchymal stem cells grown in inserts, which allowed for paracrine interactions without direct cell contact. In this co-culture model, bone marrow-derived mesenchymal stem cells regulate dermal fibroblast proliferation, migration and gene expression. When co-cultured with mesenchymal stem cells, dermal fibroblasts show increased proliferation and accelerated migration in a scratch assay. A chemotaxis assay also demonstrated that dermal fibroblasts migrate towards bone marrow-derived mesenchymal stem cells. A PCR array was used to analyze the effect of mesenchymal stem cells on dermal fibroblast gene expression. In response to mesenchymal stem cells, dermal fibroblasts up-regulate integrin alpha 7 expression and down-regulate expression of ICAM1, VCAM1 and MMP11. These observations suggest that mesenchymal stem cells may provide an important early signal for dermal fibroblast responses to cutaneous injury. PMID:19666021

Role of integrin-linked kinase in regulating phosphorylation of Akt and fibroblast survival in type I collagen matrices through a beta1 integrin viability signaling pathway.

PubMed

Nho, Richard Seonghun; Xia, Hong; Kahm, Judy; Kleidon, Jill; Diebold, Deanna; Henke, Craig A

2005-07-15

A beta1 integrin phosphatidylinositol 3-kinase/Akt pathway regulates fibroblast survival in collagen matrices. When fibroblasts attach to collagen, Akt becomes phosphorylated, providing a survival signal. In contrast, in response to mechanical forces generated during collagen contraction, Akt is dephosphorylated and fibroblasts undergo apoptosis. The kinase(s) responsible for regulating Akt phosphorylation in response to matrix-derived mechanical signals are unclear. Integrin-linked kinase (ILK) is associated with the beta1 integrin in the focal adhesion complex and as such is a candidate kinase that may regulate Akt phosphorylation and fibroblast viability. Nevertheless, there is no direct evidence that matrix-derived mechanical forces regulate cell viability by modulating ILK activity. Here, we show that ILK activity decreased in response to collagen matrix contraction, which correlated with Akt dephosphorylation and induction of fibroblast apoptosis. In contrast, enforced activation of beta1 integrin by activating antibody preserved ILK and Akt activity during collagen matrix contraction, and this is associated with protection from collagen contraction-induced apoptosis. Knock-down of ILK by small, interfering RNA (siRNA) attenuated Akt phosphorylation in response to ligation of beta1 integrin by collagen or activating antibody and enhanced fibroblast apoptosis in response to collagen contraction. Kinase dead ILK attenuated Akt phosphorylation and enhanced fibroblast apoptosis, whereas hyperactive and wild type ILK augmented Akt phosphorylation and protected fibroblasts from apoptosis. Constitutively active Akt preserved Akt activity and rescued ILK siRNA-treated fibroblasts from collagen contraction-induced apoptosis. These data establish that matrix-derived mechanical forces sensed by beta1 integrin are capable of modulating ILK activity which regulates fibroblast viability via an Akt-dependent mechanism.

ACTIVATION OF THE EGF RECEPTOR SIGNALING PATHWAY IN HUMAN AIRWAY EPITHELIAL CELLS EXPOSED TO METALS

EPA Science Inventory

We have previously shown that exposure to combustion-derived metals rapidly (within 20 min) activated mitogen-activated protein kinases (MAPK), including extracellular signal-regulated kinase (ERK), in the human bronchial epithelial cell line BEAS. To study the mechanisms respons...

EMMPRIN regulates tumor growth and metastasis by recruiting bone marrow-derived cells through paracrine signaling of SDF-1 and VEGF

PubMed Central

Chen, Yanke; Gou, Xingchun; Kong, Derek Kai; Wang, Xiaofei; Wang, Jianhui; Chen, Zeming; Huang, Chen; Zhou, Jiangbing

2015-01-01

EMMPRIN, a cell adhesion molecule highly expressed in a variety of tumors, is associated with poor prognosis in cancer patients. Mechanistically, EMMPRIN has been characterized to contribute to tumor development and progression by controlling the expression of MMPs and VEGF. In the present study, by using fluorescently labeled bone marrow-derived cells (BMDCs), we found that the down-regulation of EMMPRIN expression in cancer cells reduces tumor growth and metastasis, and is associated with the reduced recruitment of BMDCs. Further protein profiling studies suggest that EMMPRIN controls BMDC recruitment through regulating the secretion of soluble factors, notably, VEGF and SDF-1. We demonstrate that the expression and secretion of SDF-1 in tumor cells are regulated by EMMPRIN. This study reveals a novel mechanism by which EMMPRIN promotes tumor growth and metastasis by recruitment of BMDCs through controlling secretion and paracrine signaling of SDF-1 and VEGF. PMID:26416452

Depolarization Alters Phenotype, Maintains Plasticity of Predifferentiated Mesenchymal Stem Cells

PubMed Central

Sundelacruz, Sarah; Levin, Michael

2013-01-01

Although adult stem cell transplantation has been implemented as a therapy for tissue repair, it is limited by the availability of functional adult stem cells. A potential approach to generate stem and progenitor cells may be to modulate the differentiated status of somatic cells. Therefore, there is a need for a better understanding of how the differentiated phenotype of mature cells is regulated. We hypothesize that bioelectric signaling plays an important role in the maintenance of the differentiated state, as it is a functional regulator of the differentiation process in various cells and tissues. In this study, we asked whether the mature phenotype of osteoblasts and adipocytes derived from human mesenchymal stem cells (hMSCs) could be altered by modulation of their membrane potential. hMSC-derived osteoblasts and adipocytes were depolarized by treatment with ouabain, a Na+/K+ ATPase inhibitor, or by treatment with high concentrations of extracellular K+. To characterize the effect of voltage modulation on the differentiated state, the depolarized cells were evaluated for (1) the loss of differentiation markers; (2) the up-regulation of stemness markers and stem properties; and (3) differences in gene expression profiles in response to voltage modulation. hMSC-derived osteoblasts and adipocytes exhibited significant down-regulation of bone and fat tissue markers in response to depolarization, despite the presence of differentiation-inducing soluble factors, suggesting that bioelectric signaling overrides biochemical signaling in the maintenance of cell state. Suppression of the osteoblast or adipocyte phenotype was not accompanied by up-regulation of genes associated with the stem state. Thus, depolarization does not activate the stem cell genetic signature and, therefore, does not induce a full reprogramming event. However, after transdifferentiating the depolarized cells to evaluate for multi-lineage potential, depolarized osteoblasts demonstrated improved ability to achieve correct adipocyte morphology compared with nondepolarized osteoblasts. The present study thus demonstrates that depolarization reduces the differentiated phenotype of hMSC-derived cells and improves their transdifferentiation capacity, but does not restore a stem-like genetic profile. Through global transcript profiling of depolarized osteoblasts, we identified pathways that may mediate the effects of voltage signaling on cell state, which will require a detailed mechanistic inquiry in future studies. PMID:23738690

Dynamic Regulation of Platelet-Derived Growth Factor Receptor α Expression in Alveolar Fibroblasts during Realveolarization

PubMed Central

Chen, Leiling; Acciani, Thomas; Le Cras, Tim; Lutzko, Carolyn

2012-01-01

Although the importance of platelet-derived growth factor receptor (PDGFR)-α signaling during normal alveogenesis is known, it is unclear whether this signaling pathway can regulate realveolarization in the adult lung. During alveolar development, PDGFR-α–expressing cells induce α smooth muscle actin (α-SMA) and differentiate to interstitial myofibroblasts. Fibroblast growth factor (FGF) signaling regulates myofibroblast differentiation during alveolarization, whereas peroxisome proliferator-activated receptor (PPAR)-γ activation antagonizes myofibroblast differentiation in lung fibrosis. Using left lung pneumonectomy, the roles of FGF and PPAR-γ signaling in differentiation of myofibroblasts from PDGFR-α–positive precursors during compensatory lung growth were assessed. FGF receptor (FGFR) signaling was inhibited by conditionally activating a soluble dominant-negative FGFR2 transgene. PPAR-γ signaling was activated by administration of rosiglitazone. Changes in α-SMA and PDGFR-α protein expression were assessed in PDGFR-α–green fluorescent protein (GFP) reporter mice using immunohistochemistry, flow cytometry, and real-time PCR. Immunohistochemistry and flow cytometry demonstrated that the cell ratio and expression levels of PDGFR-α–GFP changed dynamically during alveolar regeneration and that α-SMA expression was induced in a subset of PDGFR-α–GFP cells. Expression of a dominant-negative FGFR2 and administration of rosiglitazone inhibited induction of α-SMA in PDGFR-α–positive fibroblasts and formation of new septae. Changes in gene expression of epithelial and mesenchymal signaling molecules were assessed after left lobe pneumonectomy, and results demonstrated that inhibition of FGFR2 signaling and increase in PPAR-γ signaling altered the expression of Shh, FGF, Wnt, and Bmp4, genes that are also important for epithelial–mesenchymal crosstalk during early lung development. Our data demonstrate for the first time that a comparable epithelial–mesenchymal crosstalk regulates fibroblast phenotypes during alveolar septation. PMID:22652199

GDF15 is a heart-derived hormone that regulates body growth.

PubMed

Wang, Ting; Liu, Jian; McDonald, Caitlin; Lupino, Katherine; Zhai, Xiandun; Wilkins, Benjamin J; Hakonarson, Hakon; Pei, Liming

2017-08-01

The endocrine system is crucial for maintaining whole-body homeostasis. Little is known regarding endocrine hormones secreted by the heart other than atrial/brain natriuretic peptides discovered over 30 years ago. Here, we identify growth differentiation factor 15 (GDF15) as a heart-derived hormone that regulates body growth. We show that pediatric heart disease induces GDF15 synthesis and secretion by cardiomyocytes. Circulating GDF15 in turn acts on the liver to inhibit growth hormone (GH) signaling and body growth. We demonstrate that blocking cardiomyocyte production of GDF15 normalizes circulating GDF15 level and restores liver GH signaling, establishing GDF15 as a bona fide heart-derived hormone that regulates pediatric body growth. Importantly, plasma GDF15 is further increased in children with concomitant heart disease and failure to thrive (FTT). Together these studies reveal a new endocrine mechanism by which the heart coordinates cardiac function and body growth. Our results also provide a potential mechanism for the well-established clinical observation that children with heart diseases often develop FTT. © 2017 The Authors. Published under the terms of the CC BY 4.0 license.

Nuclear accumulation of SHIP1 mutants derived from AML patients leads to increased proliferation of leukemic cells.

PubMed

Nalaskowski, Marcus M; Ehm, Patrick; Rehbach, Christoph; Nelson, Nina; Täger, Maike; Modest, Kathrin; Jücker, Manfred

2018-05-28

The inositol 5-phosphatase SHIP1 acts as negative regulator of intracellular signaling in myeloid cells and is a tumor suppressor in myeloid leukemogenesis. After relocalization from the cytoplasm to the plasma membrane SHIP1 terminates PI3-kinase mediated signaling processes. Furthermore, SHIP1 is also found in distinct puncta in the cell nucleus and nuclear SHIP1 has a pro-proliferative function. Here we report the identification of five nuclear export signals (NESs) which regulate together with the two known nuclear localization signals (NLSs) the nucleocytoplasmic shuttling of SHIP1. Mutation of NLSs reduced the nuclear import and mutation of NESs decreased the nuclear export of SHIP1 in the acute myeloid leukemia (AML) cell line UKE-1. Interestingly, four SHIP1 mutants (K210R, N508D, V684E, Q1153L) derived from AML patients showed a nuclear accumulation after expression in UKE-1 cells. In addition, overexpression of the AML patient-derived mutation N508D caused an increased proliferation rate of UKE-1 cells in comparison to wild type SHIP1. Furthermore, we identified serine and tyrosine phosphorylation as a molecular mechanism for the regulation of nucleocytoplasmic shuttling of SHIP1 where tyrosine phosphorylation of distinct residues i.e. Y864, Y914, Y1021 reduces nuclear localization, whereas serine phosphorylation at S933 enhances nuclear localization of SHIP1. In summary, our data further implicate nuclear SHIP1 in cellular signaling and suggest that enhanced accumulation of SHIP1 mutants in the nucleus may be a contributory factor of abnormally high proliferation of AML cells. Copyright © 2018 Elsevier Inc. All rights reserved.

Endothelial cell-derived matrix promotes the metabolic functional maturation of hepatocyte via integrin-Src signalling.

PubMed

Guo, Xinyue; Li, Weihong; Ma, Minghui; Lu, Xin; Zhang, Haiyan

2017-11-01

The extracellular matrix (ECM) microenvironment is involved in the regulation of hepatocyte phenotype and function. Recently, the cell-derived extracellular matrix has been proposed to represent the bioactive and biocompatible materials of the native ECM. Here, we show that the endothelial cell-derived matrix (EC matrix) promotes the metabolic maturation of human adipose stem cell-derived hepatocyte-like cells (hASC-HLCs) through the activation of the transcription factor forkhead box protein A2 (FOXA2) and the nuclear receptors hepatocyte nuclear factor 4 alpha (HNF4α) and pregnane X receptor (PXR). Reducing the fibronectin content in the EC matrix or silencing the expression of α5 integrin in the hASC-HLCs inhibited the effect of the EC matrix on Src phosphorylation and hepatocyte maturation. The inhibition of Src phosphorylation using the inhibitor PP2 or silencing the expression of Src in hASC-HLCs also attenuated the up-regulation of the metabolic function of hASC-HLCs in a nuclear receptor-dependent manner. These data elucidate integrin-Src signalling linking the extrinsic EC matrix signals and metabolic functional maturation of hepatocyte. This study provides a model for studying the interaction between hepatocytes and non-parenchymal cell-derived matrix. © 2017 The Authors. Journal of Cellular and Molecular Medicine published by John Wiley & Sons Ltd and Foundation for Cellular and Molecular Medicine.

Involvement of WNT Signaling in the Regulation of Gestational Age-Dependent Umbilical Cord-Derived Mesenchymal Stem Cell Proliferation

PubMed Central

Shono, Akemi; Yoshida, Makiko; Yamana, Keiji; Thwin, Khin Kyae Mon; Kuroda, Jumpei; Kurokawa, Daisuke; Koda, Tsubasa; Nishida, Kosuke; Ikuta, Toshihiko; Mizobuchi, Masami; Taniguchi-Ikeda, Mariko

2017-01-01

Mesenchymal stem cells (MSCs) are a heterogeneous cell population that is isolated initially from the bone marrow (BM) and subsequently almost all tissues including umbilical cord (UC). UC-derived MSCs (UC-MSCs) have attracted an increasing attention as a source for cell therapy against various degenerative diseases due to their vigorous proliferation and differentiation. Although the cell proliferation and differentiation of BM-derived MSCs is known to decline with age, the functional difference between preterm and term UC-MSCs is poorly characterized. In the present study, we isolated UC-MSCs from 23 infants delivered at 22–40 weeks of gestation and analyzed their gene expression and cell proliferation. Microarray analysis revealed that global gene expression in preterm UC-MSCs was distinct from term UC-MSCs. WNT signaling impacts on a variety of tissue stem cell proliferation and differentiation, and its pathway genes were enriched in differentially expressed genes between preterm and term UC-MSCs. Cell proliferation of preterm UC-MSCs was significantly enhanced compared to term UC-MSCs and counteracted by WNT signaling inhibitor XAV939. Furthermore, WNT2B expression in UC-MSCs showed a significant negative correlation with gestational age (GA). These results suggest that WNT signaling is involved in the regulation of GA-dependent UC-MSC proliferation. PMID:29138639

A food-derived synergist of NGF signaling: identification of protein tyrosine phosphatase 1B as a key regulator of NGF receptor-initiated signal transduction.

PubMed

Shibata, Takahiro; Nakahara, Hiroko; Kita, Narumi; Matsubara, Yui; Han, Chunguang; Morimitsu, Yasujiro; Iwamoto, Noriko; Kumagai, Yoshito; Nishida, Motohiro; Kurose, Hitoshi; Aoki, Naohito; Ojika, Makoto; Uchida, Koji

2008-12-01

Neurotrophins, such as the nerve growth factor (NGF), play an essential role in the growth, development, survival and functional maintenance of neurons in the central and peripheral systems. They also prevent neuronal cell death under various stressful conditions, such as ischemia and neurodegenerative disorders. NGF induces cell differentiation and neurite outgrowth by binding with and activating the NGF receptor tyrosine kinase followed by activation of a variety of signaling cascades. We have investigated the NGF-dependent neuritogenesis enhancer potential of a food-derived small molecule contained in Brassica vegetables and identified the protein tyrosine phosphatase (PTP) 1B as a key regulator of the NGF receptor-initiated signal transduction. Based on an extensive screening of Brassica vegetable extracts for the neuritogenic-promoting activity in the rat pheochromocytoma cell line PC12, we found the Japanese horseradish, wasabi (Wasabia japonica, syn. Eutrema wasabi), as the richest source and identified 6-methylsulfinylhexyl isothiocyanate (6-HITC), an analogue of sulforaphane isolated from broccoli, as one of the major neuritogenic enhancers in the wasabi. 6-HITC strongly enhanced the neurite outgrowth and neurofilament expression elicited by a low-concentration of NGF that alone was insufficient to induce neuronal differentiation. 6-HITC also facilitated the sustained-phosphorylation of the extracellular signal-regulated kinase and the autophosphorylation of the NGF receptor TrkA. It was found that PTP1B act as a phosphatase capable of dephosphorylating Tyr-490 of TrkA and was inactivated by 6-HITC in a redox-dependent manner. The identification of PTP1B as a regulator of NGF signaling may provide new clues about the chemoprotective potential of food components, such as isothiocyanates.

CHIR99021 promotes self-renewal of mouse embryonic stem cells by modulation of protein-encoding gene and long intergenic non-coding RNA expression

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

Wu, Yongyan; Key Laboratory of Animal Biotechnology, Ministry of Agriculture, Northwest A and F University, Yangling 712100, Shaanxi; Ai, Zhiying

2013-10-15

Embryonic stem cells (ESCs) can proliferate indefinitely in vitro and differentiate into cells of all three germ layers. These unique properties make them exceptionally valuable for drug discovery and regenerative medicine. However, the practical application of ESCs is limited because it is difficult to derive and culture ESCs. It has been demonstrated that CHIR99021 (CHIR) promotes self-renewal and enhances the derivation efficiency of mouse (m)ESCs. However, the downstream targets of CHIR are not fully understood. In this study, we identified CHIR-regulated genes in mESCs using microarray analysis. Our microarray data demonstrated that CHIR not only influenced the Wnt/β-catenin pathway bymore » stabilizing β-catenin, but also modulated several other pluripotency-related signaling pathways such as TGF-β, Notch and MAPK signaling pathways. More detailed analysis demonstrated that CHIR inhibited Nodal signaling, while activating bone morphogenetic protein signaling in mESCs. In addition, we found that pluripotency-maintaining transcription factors were up-regulated by CHIR, while several developmental-related genes were down-regulated. Furthermore, we found that CHIR altered the expression of epigenetic regulatory genes and long intergenic non-coding RNAs. Quantitative real-time PCR results were consistent with microarray data, suggesting that CHIR alters the expression pattern of protein-encoding genes (especially transcription factors), epigenetic regulatory genes and non-coding RNAs to establish a relatively stable pluripotency-maintaining network. - Highlights: • Combined use of CHIR with LIF promotes self-renewal of J1 mESCs. • CHIR-regulated genes are involved in multiple pathways. • CHIR inhibits Nodal signaling and promotes Bmp4 expression to activate BMP signaling. • Expression of epigenetic regulatory genes and lincRNAs is altered by CHIR.« less

Existing branches correlatively inhibit further branching in Trifolium repens: possible mechanisms

PubMed Central

Thomas, R. G.; Hay, M. J. M.

2011-01-01

In Trifolium repens removal of any number of existing branches distal to a nodal root stimulates development of axillary buds further along the stem such that the complement of branches distal to a nodal root remains constant. This study aimed to assess possible mechanisms by which existing branches correlatively inhibit the outgrowth of axillary buds distal to them. Treatments were applied to basal branches to evaluate the roles of three postulated inhibitory mechanisms: (I) the transport of a phloem-mobile inhibitory feedback signal from branches into the main stem; (II) the polar flow of auxin from branches into the main stem acting to limit further branch development; or (III) the basal branches functioning as sinks for a net root-derived stimulatory signal (NRS). Results showed that transport of auxin, or of a non-auxin phloem-mobile signal, from basal branches did not influence regulation of correlative inhibition and were consistent with the possibility that the intra-plant distribution of NRS could be involved in the correlative inhibition of distal buds by basal branches. This study supports existing evidence that regulation of branching in T. repens is dominated by a root-derived stimulatory signal, initially distributed via the xylem, the characterization of which will progress the generic understanding of branching regulation. PMID:21071681

Small Molecule Signaling Agents: The Integrated Chemistry and Biochemistry of Nitrogen Oxides, Oxides of Carbon, Dioxygen, Hydrogen Sulfide, and Their Derived Species

PubMed Central

Fukuto, Jon M.; Carrington, Samantha J.; Tantillo, Dean J.; Harrison, Jason G.; Ignarro, Louis J.; Freeman, Bruce A.; Chen, Andrew; Wink, David A.

2014-01-01

Several small molecule species formally known primarily as toxic gases have, over the past 20 years, been shown to be endogenously generated signaling molecules. The biological signaling associated with the small molecules NO, CO, H2S (and the nonendogenously generated O2), and their derived species have become a topic of extreme interest. It has become increasingly clear that these small molecule signaling agents form an integrated signaling web that affects/regulates numerous physiological processes. The chemical interactions between these species and each other or biological targets is an important factor in their roles as signaling agents. Thus, a fundamental understanding of the chemistry of these molecules is essential to understanding their biological/physiological utility. This review focuses on this chemistry and attempts to establish the chemical basis for their signaling functions. PMID:22263838

Mesenchymal stem cells induce dermal fibroblast responses to injury

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

Smith, Andria N., E-mail: snosmith@u.washington.edu; Willis, Elise, E-mail: elise.willis@gmail.com; Chan, Vincent T.

2010-01-01

Although bone marrow-derived mesenchymal stem cells have been shown to promote repair when applied to cutaneous wounds, the mechanism for this response remains to be determined. The aim of this study was to determine the effects of paracrine signaling from mesenchymal stem cells on dermal fibroblast responses to injury including proliferation, migration and expression of genes important in wound repair. Dermal fibroblasts were co-cultured with bone marrow-derived mesenchymal stem cells grown in inserts, which allowed for paracrine interactions without direct cell contact. In this co-culture model, bone marrow-derived mesenchymal stem cells regulate dermal fibroblast proliferation, migration and gene expression. Whenmore » co-cultured with mesenchymal stem cells, dermal fibroblasts show increased proliferation and accelerated migration in a scratch assay. A chemotaxis assay also demonstrated that dermal fibroblasts migrate towards bone marrow-derived mesenchymal stem cells. A PCR array was used to analyze the effect of mesenchymal stem cells on dermal fibroblast gene expression. In response to mesenchymal stem cells, dermal fibroblasts up-regulate integrin alpha 7 expression and down-regulate expression of ICAM1, VCAM1 and MMP11. These observations suggest that mesenchymal stem cells may provide an important early signal for dermal fibroblast responses to cutaneous injury.« less

Low oleic acid-derived repression of jasmonic acid-inducible defense responses requires the WRKY50 and WRKY51 proteins

USDA-ARS?s Scientific Manuscript database

Signaling induced upon a reduction in oleic acid (18:1) levels simultaneously up-regulates salicylic acid (SA)-mediated responses and inhibits jasmonic acid (JA)-inducible defenses, resulting in enhanced resistance to biotrophs but increased susceptibility to necrotrophs. SA and the signaling compon...

Coordinated Proliferation and Differentiation of Human-Induced Pluripotent Stem Cell-Derived Cardiac Progenitor Cells Depend on Bone Morphogenetic Protein Signaling Regulation by GREMLIN 2

PubMed Central

Bylund, Jeffery B.; Trinh, Linh T.; Awgulewitsch, Cassandra P.; Paik, David T.; Jetter, Christopher; Jha, Rajneesh; Zhang, Jianhua; Nolan, Kristof; Xu, Chunhui; Thompson, Thomas B.; Kamp, Timothy J.

2017-01-01

Heart development depends on coordinated proliferation and differentiation of cardiac progenitor cells (CPCs), but how the two processes are synchronized is not well understood. Here, we show that the secreted Bone Morphogenetic Protein (BMP) antagonist GREMLIN 2 (GREM2) is induced in CPCs shortly after cardiac mesoderm specification during differentiation of human pluripotent stem cells. GREM2 expression follows cardiac lineage differentiation independently of the differentiation method used, or the origin of the pluripotent stem cells, suggesting that GREM2 is linked to cardiogenesis. Addition of GREM2 protein strongly increases cardiomyocyte output compared to established procardiogenic differentiation methods. Our data show that inhibition of canonical BMP signaling by GREM2 is necessary to promote proliferation of CPCs. However, canonical BMP signaling inhibition alone is not sufficient to induce cardiac differentiation, which depends on subsequent JNK pathway activation specifically by GREM2. These findings may have broader implications in the design of approaches to orchestrate growth and differentiation of pluripotent stem cell-derived lineages that depend on precise regulation of BMP signaling. PMID:28125926

Coordinated Proliferation and Differentiation of Human-Induced Pluripotent Stem Cell-Derived Cardiac Progenitor Cells Depend on Bone Morphogenetic Protein Signaling Regulation by GREMLIN 2.

PubMed

Bylund, Jeffery B; Trinh, Linh T; Awgulewitsch, Cassandra P; Paik, David T; Jetter, Christopher; Jha, Rajneesh; Zhang, Jianhua; Nolan, Kristof; Xu, Chunhui; Thompson, Thomas B; Kamp, Timothy J; Hatzopoulos, Antonis K

2017-05-01

Heart development depends on coordinated proliferation and differentiation of cardiac progenitor cells (CPCs), but how the two processes are synchronized is not well understood. Here, we show that the secreted Bone Morphogenetic Protein (BMP) antagonist GREMLIN 2 (GREM2) is induced in CPCs shortly after cardiac mesoderm specification during differentiation of human pluripotent stem cells. GREM2 expression follows cardiac lineage differentiation independently of the differentiation method used, or the origin of the pluripotent stem cells, suggesting that GREM2 is linked to cardiogenesis. Addition of GREM2 protein strongly increases cardiomyocyte output compared to established procardiogenic differentiation methods. Our data show that inhibition of canonical BMP signaling by GREM2 is necessary to promote proliferation of CPCs. However, canonical BMP signaling inhibition alone is not sufficient to induce cardiac differentiation, which depends on subsequent JNK pathway activation specifically by GREM2. These findings may have broader implications in the design of approaches to orchestrate growth and differentiation of pluripotent stem cell-derived lineages that depend on precise regulation of BMP signaling.

Uncaria rhynchophylla and rhynchophylline improved kainic acid-induced epileptic seizures via IL-1β and brain-derived neurotrophic factor.

PubMed

Ho, Tin-Yun; Tang, Nou-Ying; Hsiang, Chien-Yun; Hsieh, Ching-Liang

2014-05-15

Uncaria rhynchophylla (UR) has been used for the treatment of convulsions and epilepsy in traditional Chinese medicine. This study reported the major anti-convulsive signaling pathways and effective targets of UR and rhynchophylline (RP) using genomic and immunohistochemical studies. Epileptic seizure model was established by intraperitoneal injection of kainic acid (KA) in rats. Electroencephalogram and electromyogram recordings indicated that UR and RP improved KA-induced epileptic seizures. Toll-like receptor (TLR) and neurotrophin signaling pathways were regulated by UR in both cortex and hippocampus of KA-treated rats. KA upregulated the expression levels of interleukin-1β (IL-1β) and brain-derived neurotrophin factor (BDNF), which were involved in TLR and neurotrophin signaling pathways, respectively. However, UR and RP downregulated the KA-induced IL-1β and BDNF gene expressions. Our findings suggested that UR and RP exhibited anti-convulsive effects in KA-induced rats via the regulation of TLR and neurotrophin signaling pathways, and the subsequent inhibition of IL-1β and BDNF gene expressions. Copyright © 2014 Elsevier GmbH. All rights reserved.

Taspine derivative 12k suppressed A549 cell migration through the Wnt/β-catenin and EphrinB2 signaling pathway.

PubMed

Dai, Bingling; Ma, Yujiao; Yang, Tianfeng; Wang, Wenjie; Zhang, Yanmin

2017-03-01

12k, a taspine derivative, has been demonstrated to have the potent anti-tumor activity in lung cancer and colorectal cancer. The study aims to further explore the underlying mechanisms of 12k on A549 cell migration in vitro. Our data demonstrated that 12k negatively regulated Wnt signaling pathway by suppressing the phosphorylation of LRP5/6, and inhibiting the expression and nuclear translocation of β-catenin. 12k was shown to downregulate MMP3 and MMP7 expression which regulated by β-catenin interacts with TCF/LEF in the nucleus, and effectively impaired the related migration protein expression of MMP2 and MMP9 in A549 cells. In addition, 12k repressed the EphrinB2 and its PDZ protein, impairing the VEGFR2 and VEGFR3 expression in A549 cells, as well as inhibited the downstream of VEGFR2 included PI3K/AKT/mTOR and ERK/MAPK signaling pathways. Taken together, our findings revealed that 12k suppressed migration of A549 cells through the Wnt/β-catenin signaling pathway and EphrinB2 related signaling pathway. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

Design and synthesis of imidazopyridine analogues as inhibitors of phosphoinositide 3-kinase signaling and angiogenesis.

PubMed

Kim, Okseon; Jeong, Yujeong; Lee, Hyunseung; Hong, Sun-Sun; Hong, Sungwoo

2011-04-14

Phosphatidylinositol 3-kinase α (PI3Kα) is an important regulator of intracellular signaling pathways, controlling remarkably diverse arrays of physiological processes. Because the PI3K pathway is frequently up-regulated in human cancers, the inhibition of PI3Kα can be a promising approach to cancer therapy. In this study, we have designed and synthesized a new series of imidazo[1,2-a]pyridine derivatives as PI3Kα inhibitors through the fragment-growing strategy. By varying groups at the 3- and 6-positions of imidazo[1,2-a]pyridines, we studied the structure-activity relationships (SAR) profiles and identified a series of potent PI3Kα inhibitors. Representative derivatives showed good activity in cellular proliferation and apoptosis assays. Moreover, these inhibitors exhibited noteworthy antiangiogenic activity.

Characterization of Gonadotrope Secretoproteome Identifies Neurosecretory Protein VGF-derived Peptide Suppression of Follicle-stimulating Hormone Gene Expression.

PubMed

Choi, Soon Gang; Wang, Qian; Jia, Jingjing; Chikina, Maria; Pincas, Hanna; Dolios, Georgia; Sasaki, Kazuki; Wang, Rong; Minamino, Naoto; Salton, Stephen R J; Sealfon, Stuart C

2016-09-30

Reproductive function is controlled by the pulsatile release of hypothalamic gonadotropin-releasing hormone (GnRH), which regulates the expression of the gonadotropins luteinizing hormone and FSH in pituitary gonadotropes. Paradoxically, Fshb gene expression is maximally induced at lower frequency GnRH pulses, which provide a very low average concentration of GnRH stimulation. We studied the role of secreted factors in modulating gonadotropin gene expression. Inhibition of secretion specifically disrupted gonadotropin subunit gene regulation but left early gene induction intact. We characterized the gonadotrope secretoproteome and global mRNA expression at baseline and after Gα s knockdown, which has been found to increase Fshb gene expression (1). We identified 1077 secreted proteins or peptides, 19 of which showed mRNA regulation by GnRH or/and Gα s knockdown. Among several novel secreted factors implicated in Fshb gene regulation, we focused on the neurosecretory protein VGF. Vgf mRNA, whose gene has been implicated in fertility (2), exhibited high induction by GnRH and depended on Gα s In contrast with Fshb induction, Vgf induction occurred preferentially at high GnRH pulse frequency. We hypothesized that a VGF-derived peptide might regulate Fshb gene induction. siRNA knockdown or extracellular immunoneutralization of VGF augmented Fshb mRNA induction by GnRH. GnRH stimulated the secretion of the VGF-derived peptide NERP1. NERP1 caused a concentration-dependent decrease in Fshb gene induction. These findings implicate a VGF-derived peptide in selective regulation of the Fshb gene. Our results support the concept that signaling specificity from the cell membrane GnRH receptor to the nuclear Fshb gene involves integration of intracellular signaling and exosignaling regulatory motifs. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

Characterization of Gonadotrope Secretoproteome Identifies Neurosecretory Protein VGF-derived Peptide Suppression of Follicle-stimulating Hormone Gene Expression*

PubMed Central

Wang, Qian; Jia, Jingjing; Chikina, Maria; Pincas, Hanna; Dolios, Georgia; Sasaki, Kazuki; Wang, Rong; Minamino, Naoto; Sealfon, Stuart C.

2016-01-01

Reproductive function is controlled by the pulsatile release of hypothalamic gonadotropin-releasing hormone (GnRH), which regulates the expression of the gonadotropins luteinizing hormone and FSH in pituitary gonadotropes. Paradoxically, Fshb gene expression is maximally induced at lower frequency GnRH pulses, which provide a very low average concentration of GnRH stimulation. We studied the role of secreted factors in modulating gonadotropin gene expression. Inhibition of secretion specifically disrupted gonadotropin subunit gene regulation but left early gene induction intact. We characterized the gonadotrope secretoproteome and global mRNA expression at baseline and after Gαs knockdown, which has been found to increase Fshb gene expression (1). We identified 1077 secreted proteins or peptides, 19 of which showed mRNA regulation by GnRH or/and Gαs knockdown. Among several novel secreted factors implicated in Fshb gene regulation, we focused on the neurosecretory protein VGF. Vgf mRNA, whose gene has been implicated in fertility (2), exhibited high induction by GnRH and depended on Gαs. In contrast with Fshb induction, Vgf induction occurred preferentially at high GnRH pulse frequency. We hypothesized that a VGF-derived peptide might regulate Fshb gene induction. siRNA knockdown or extracellular immunoneutralization of VGF augmented Fshb mRNA induction by GnRH. GnRH stimulated the secretion of the VGF-derived peptide NERP1. NERP1 caused a concentration-dependent decrease in Fshb gene induction. These findings implicate a VGF-derived peptide in selective regulation of the Fshb gene. Our results support the concept that signaling specificity from the cell membrane GnRH receptor to the nuclear Fshb gene involves integration of intracellular signaling and exosignaling regulatory motifs. PMID:27466366

The skeletal cell-derived molecule sclerostin drives bone marrow adipogenesis.

PubMed

Fairfield, Heather; Falank, Carolyne; Harris, Elizabeth; Demambro, Victoria; McDonald, Michelle; Pettitt, Jessica A; Mohanty, Sindhu T; Croucher, Peter; Kramer, Ina; Kneissel, Michaela; Rosen, Clifford J; Reagan, Michaela R

2018-02-01

The bone marrow niche is a dynamic and complex microenvironment that can both regulate, and be regulated by the bone matrix. Within the bone marrow (BM), mesenchymal stromal cell (MSC) precursors reside in a multi-potent state and retain the capacity to differentiate down osteoblastic, adipogenic, or chondrogenic lineages in response to numerous biochemical cues. These signals can be altered in various pathological states including, but not limited to, osteoporotic-induced fracture, systemic adiposity, and the presence of bone-homing cancers. Herein we provide evidence that signals from the bone matrix (osteocytes) determine marrow adiposity by regulating adipogenesis in the bone marrow. Specifically, we found that physiologically relevant levels of Sclerostin (SOST), which is a Wnt-inhibitory molecule secreted from bone matrix-embedded osteocytes, can induce adipogenesis in 3T3-L1 cells, mouse ear- and BM-derived MSCs, and human BM-derived MSCs. We demonstrate that the mechanism of SOST induction of adipogenesis is through inhibition of Wnt signaling in pre-adipocytes. We also demonstrate that a decrease of sclerostin in vivo, via both genetic and pharmaceutical methods, significantly decreases bone marrow adipose tissue (BMAT) formation. Overall, this work demonstrates a direct role for SOST in regulating fate determination of BM-adipocyte progenitors. This provides a novel mechanism for which BMAT is governed by the local bone microenvironment, which may prove relevant in the pathogenesis of certain diseases involving marrow adipose. Importantly, with anti-sclerostin therapy at the forefront of osteoporosis treatment and a greater recognition of the role of BMAT in disease, these data are likely to have important clinical implications. © 2017 Wiley Periodicals, Inc.

Mitochondrial morphology transitions and functions: implications for retrograde signaling?

PubMed Central

Picard, Martin; Shirihai, Orian S.; Gentil, Benoit J.

2013-01-01

In response to cellular and environmental stresses, mitochondria undergo morphology transitions regulated by dynamic processes of membrane fusion and fission. These events of mitochondrial dynamics are central regulators of cellular activity, but the mechanisms linking mitochondrial shape to cell function remain unclear. One possibility evaluated in this review is that mitochondrial morphological transitions (from elongated to fragmented, and vice-versa) directly modify canonical aspects of the organelle's function, including susceptibility to mitochondrial permeability transition, respiratory properties of the electron transport chain, and reactive oxygen species production. Because outputs derived from mitochondrial metabolism are linked to defined cellular signaling pathways, fusion/fission morphology transitions could regulate mitochondrial function and retrograde signaling. This is hypothesized to provide a dynamic interface between the cell, its genome, and the fluctuating metabolic environment. PMID:23364527

Cartilage-specific RBPjκ-dependent and -independent Notch signals regulate cartilage and bone development

PubMed Central

Kohn, Anat; Dong, Yufeng; Mirando, Anthony J.; Jesse, Alana M.; Honjo, Tasuku; Zuscik, Michael J.; O’Keefe, Regis J.; Hilton, Matthew J.

2012-01-01

The Notch signaling pathway has emerged as an important regulator of endochondral bone formation. Although recent studies have examined the role of Notch in mesenchymal and chondro-osteo progenitor cell populations, there has yet to be a true examination of Notch signaling specifically within developing and committed chondrocytes, or a determination of whether cartilage and bone formation are regulated via RBPjκ-dependent or -independent Notch signaling mechanisms. To develop a complete understanding of Notch signaling during cartilage and bone development we generated and compared general Notch gain-of-function (Rosa-NICDf/+), RBPjκ-deficient (Rbpjκf/f), and RBPjκ-deficient Notch gain-of-function (Rosa-NICDf/+;Rbpjκf/f) conditional mutant mice, where activation or deletion of floxed alleles were specifically targeted to mesenchymal progenitors (Prx1Cre) or committed chondrocytes (inducible Col2CreERT2). These data demonstrate, for the first time, that Notch regulation of chondrocyte maturation is solely mediated via the RBPjκ-dependent pathway, and that the perichodrium or osteogenic lineage probably influences chondrocyte terminal maturation and turnover of the cartilage matrix. Our study further identifies the cartilage-specific RBPjκ-independent pathway as crucial for the proper regulation of chondrocyte proliferation, survival and columnar chondrocyte organization. Unexpectedly, the RBPjκ-independent Notch pathway was also identified as an important long-range cell non-autonomous regulator of perichondral bone formation and an important cartilage-derived signal required for coordinating chondrocyte and osteoblast differentiation during endochondral bone development. Finally, cartilage-specific RBPjκ-independent Notch signaling likely regulates Ihh responsiveness during cartilage and bone development. PMID:22354840

Apelin: an endogenous peptide essential for cardiomyogenic differentiation of mesenchymal stem cells via activating extracellular signal-regulated kinase 1/2 and 5.

PubMed

Wang, Li; Zhu, Zhi-Ming; Zhang, Ning-Kun; Fang, Zhi-Rong; Xu, Xiao-Hong; Zheng, Nan; Gao, Lian-Ru

2016-05-01

Growing evidence has shown that apelin/APJ system functions as a critical mediator of cardiac development as well as cardiovascular function. Here, we investigated the role of apelin in the cardiomyogenic differentiation of mesenchymal stem cells derived from Wharton's jelly of human umbilical cord in vitro. In this research, we used RNA interference methodology and gene transfection technique to regulate the expression of apelin in Wharton's jelly-derived mesenchymal stem cells and induced cells with a effective cardiac differentiation protocol including 5-azacytidine and bFGF. Four weeks after induction, induced cells assumed a stick-like morphology and myotube-like structures except apelin-silenced cells and the control group. The silencing expression of apelin in Wharton's jelly-derived mesenchymal stem cells decreased the expression of several critical cardiac progenitor transcription factors (Mesp1, Mef2c, NKX2.5) and cardiac phenotypes (cardiac α-actin, β-MHC, cTnT, and connexin-43). Meanwhile, endogenous compensation of apelin contributed to differentiating into cells with characteristics of cardiomyocytes in vitro. Further experiment showed that exogenous apelin peptide rescued the cardiomyogenic differentiation of apelin-silenced mesenchymal stem cells in the early stage (1-4 days) of induction. Remarkably, our experiment indicated that apelin up-regulated cardiac specific genes in Wharton's jelly-derived mesenchymal stem cells via activating extracellular signal-regulated kinase (ERK) 1/2 and 5. © 2016 International Federation for Cell Biology.

Crimpy enables discrimination of presynaptic and postsynaptic pools of a BMP at the Drosophila neuromuscular junction.

PubMed

James, Rebecca E; Hoover, Kendall M; Bulgari, Dinara; McLaughlin, Colleen N; Wilson, Christopher G; Wharton, Kristi A; Levitan, Edwin S; Broihier, Heather T

2014-12-08

Distinct pools of the bone morphogenetic protein (BMP) Glass bottom boat (Gbb) control structure and function of the Drosophila neuromuscular junction. Specifically, motoneuron-derived Gbb regulates baseline neurotransmitter release, whereas muscle-derived Gbb regulates neuromuscular junction growth. Yet how cells differentiate between these ligand pools is not known. Here we present evidence that the neuronal Gbb-binding protein Crimpy (Cmpy) permits discrimination of pre- and postsynaptic ligand by serving sequential functions in Gbb signaling. Cmpy first delivers Gbb to dense core vesicles (DCVs) for activity-dependent release from presynaptic terminals. In the absence of Cmpy, Gbb is no longer associated with DCVs and is not released by activity. Electrophysiological analyses demonstrate that Cmpy promotes Gbb's proneurotransmission function. Surprisingly, the Cmpy ectodomain is itself released upon DCV exocytosis, arguing that Cmpy serves a second function in BMP signaling. In addition to trafficking Gbb to DCVs, we propose that Gbb/Cmpy corelease from presynaptic terminals defines a neuronal protransmission signal. Copyright © 2014 Elsevier Inc. All rights reserved.

Crimpy enables discrimination of pre and postsynaptic pools of a BMP at the Drosophila NMJ

PubMed Central

James, Rebecca E.; Hoover, Kendall M.; Bulgari, Dinara; McLaughlin, Colleen N.; Wilson, Christopher G.; Wharton, Kristi A.; Levitan, Edwin S.; Broihier, Heather T.

2014-01-01

Summary Distinct pools of the BMP Glass bottom boat (Gbb) control structure and function of the Drosophila neuromuscular junction. Specifically, motoneuron-derived Gbb regulates baseline neurotransmitter release, while muscle-derived Gbb regulates NMJ growth. Yet how cells differentiate between these ligand pools is not known. Here we present evidence that the neuronal Gbb-binding protein Crimpy (Cmpy) permits discrimination of pre and postsynaptic ligand by serving sequential functions in Gbb signaling. Cmpy first delivers Gbb to dense core vesicles (DCVs) for activity-dependent release from presynaptic terminals. In the absence of Cmpy, Gbb is no longer associated with DCVs and is not released by activity. Electrophysiological analyses demonstrate that Cmpy promotes Gbb's pro-neurotransmission function. Surprisingly, the Cmpy ectodomain is itself released upon DCV exocytosis, arguing that Cmpy serves a second function in BMP signaling. In addition to trafficking Gbb to DCVs, we propose that Gbb/Cmpy co-release from presynaptic terminals defines a neuronal pro-transmission signal. PMID:25453556

FGF10/FGFR2b signaling is essential for cardiac fibroblast development and growth of the myocardium

PubMed Central

Vega-Hernández, Mónica; Kovacs, Attila; De Langhe, Stijn; Ornitz, David M.

2011-01-01

The epicardium serves as a source of growth factors that regulate myocardial proliferation and as a source of epicardial-derived cells (EPDC), which give rise to interstitial cardiac fibroblasts and perivascular cells. These progenitors populate the compact myocardium to become part of the mature coronary vasculature and fibrous skeleton of the heart. Little is known about the mechanisms that regulate EPDC migration into the myocardium or the functions carried out by these cells once they enter the myocardium. However, it has been proposed that cardiac fibroblasts are important for growth of the heart during late gestation and are a source of homeostatic factors in the adult. Here, we identify a myocardial to epicardial fibroblast growth factor (FGF) signal, mediated by FGF10 and FGFR2b, that is essential for movement of cardiac fibroblasts into the compact myocardium. Inactivation of this signaling pathway results in fewer epicardial derived cells within the compact myocardium, decreased myocardial proliferation and a resulting smaller thin-walled heart. PMID:21750042

Physiology of Cholangiocytes

PubMed Central

Tabibian, James H.; Masyuk, Anatoliy I.; Masyuk, Tetyana V.; O’Hara, Steven P.; LaRusso, Nicholas F.

2013-01-01

Cholangiocytes are epithelial cells that line the intra- and extrahepatic ducts of the biliary tree. The main physiologic function of cholangiocytes is modification of hepatocyte-derived bile, an intricate process regulated by hormones, peptides, nucleotides, neurotransmitters, and other molecules through intracellular signaling pathways and cascades. The mechanisms and regulation of bile modification are reviewed herein. PMID:23720296

Neopterin negatively regulates expression of ABCA1 and ABCG1 by the LXRα signaling pathway in THP-1 macrophage-derived foam cells.

PubMed

Yan, Jin-quan; Tan, Chun-zhi; Wu, Jin-hua; Zhang, Dong-cui; Chen, Ji-ling; Zeng, Bin-yuan; Jiang, Yu-ping; Nie, Jin; Liu, Wei; Liu, Qin; Dai, Hao

2013-07-01

To investigate the effects of neopterin on ABCA1 expression and cholesterol efflux in human THP-1 macrophage-derived foam cells, and to explore the role of the liver X receptor alpha (LXRα) involved. In the present study, THP-1 cells were pre-incubated with ox-LDL to become foam cells. The protein and mRNA expression were examined by Western blot assays and real-time quantitative PCR, respectively. Liquid scintillation counting and high performance liquid chromatography assays were used to test cellular cholesterol efflux and cholesterol content. Neopterin decreased ABCA1 expression and cholesterol efflux in a time- and concentration-dependent manner in THP-1 macrophage-derived foam cells, and the LXRα siRNA can reverse the inhibitory effects induced by neopterin. Neoterin has a negative regulation on ABCA1 expression via the LXRα signaling pathway, which suggests the aggravated effects of neopterin on atherosclerosis.

Interplant Aboveground Signaling Prompts Upregulation of Auxin Promoter and Malate Transporter as Part of Defensive Response in the Neighboring Plants.

PubMed

Sweeney, Connor; Lakshmanan, Venkatachalam; Bais, Harsh P

2017-01-01

When disrupted by stimuli such as herbivory, pathogenic infection, or mechanical wounding, plants secrete signals such as root exudates and volatile organic compounds (VOCs). The emission of VOCs induces a response in the neighboring plant communities and can improve plant fitness by alerting nearby plants of an impending threat and prompting them to alter their physiology for defensive purposes. In this study, we investigated the role of plant-derived signals, released as a result of mechanical wounding, that may play a role in intraspecific communication between Arabidopsis thaliana communities. Plant-derived signals released by the wounded plant resulted in more elaborate root development in the neighboring, unwounded plants. Such plant-derived signals also upregulated the Aluminum-activated malate transporter ( ALMT1 ) responsible for the secretion of malic acid (MA) and the DR5 promoter, an auxin responsive promoter concentrated in root apex of the neighboring plants. We speculate that plant-derived signal-induced upregulation of root-specific ALMT1 in the undamaged neighboring plants sharing the environment with stressed plants may associate more with the benign microbes belowground. We also observed increased association of beneficial bacterium Bacillus subtilis UD1022 on roots of the neighboring plants sharing environment with the damaged plants. Wounding-induced plant-derived signals therefore induce defense mechanisms in the undamaged, local plants, eliciting a two-pronged preemptive response of more rapid root growth and up-regulation of ALMT1 , resulting in increased association with beneficial microbiome.

Interplay between TGF-β signaling and receptor tyrosine kinases in tumor development.

PubMed

Shi, Qiaoni; Chen, Ye-Guang

2017-10-01

Transforming growth factor-β (TGF-β) signaling regulates cell proliferation, differentiation, migration and death, and plays a critical role in embryogenesis and tissue homeostasis. Its deregulation results in various diseases including tumor formation. Receptor tyrosine kinases (RTKs), such as epidermal growth factor receptor (EGFR), fibroblast growth factor receptor (FGFR), vascular endothelial growth factor receptor (VEGFR) and platelet-derived growth factor receptor (PDGFR), also play key roles in the development and progression of many types of tumors. It has been realized that TGF-β signaling and RTK pathways interact with each other and their interplay is important for cancer development. They are mutually regulated and cooperatively modulate cell survival and migration, epithelial-mesenchymal transition, and tumor microenvironment to accelerate tumorigenesis and tumor metastasis. RTKs can modulate Smad-dependent transcription or cooperate with TGF-β to potentiate its oncogenic activity, while TGF-β signaling can in turn control RTK signaling by regulating their activities or expression. This review summarizes current understandings of the interplay between TGF-β signaling and RTKs and its influence on tumor development.

The imidazopyridine derivative JK184 reveals dual roles for microtubules in Hedgehog signaling.

PubMed

Cupido, Tommaso; Rack, Paul G; Firestone, Ari J; Hyman, Joel M; Han, Kyuho; Sinha, Surajit; Ocasio, Cory A; Chen, James K

2009-01-01

Eradicating hedgehogs: The title molecule has been previously identified as a potent inhibitor of the Hedgehog signaling pathway, which gives embryonic cells information needed to develop properly. This molecule is shown to modulate Hedgehog target gene expression by depolymerizing microtubules, thus revealing dual roles of the cytoskeleton in pathway regulation (see figure).

Integrating Retinoic Acid Signaling with Brain Function

ERIC Educational Resources Information Center

Luo, Tuanlian; Wagner, Elisabeth; Drager, Ursula C.

2009-01-01

The vitamin A derivative retinoic acid (RA) regulates the transcription of about a 6th of the human genome. Compelling evidence indicates a role of RA in cognitive activities, but its integration with the molecular mechanisms of higher brain functions is not known. Here we describe the properties of RA signaling in the mouse, which point to…

Shunt regulation electric power system

NASA Technical Reports Server (NTRS)

Wright, W. H.; Bless, J. J. (Inventor)

1971-01-01

A regulated electric power system having load and return bus lines is described. A plurality of solar cells interconnected in a power supplying relationship and having a power shunt tap point electrically spaced from the bus lines is provided. A power dissipator is connected to the shunt tap point and provides for a controllable dissipation of excess energy supplied by the solar cells. A dissipation driver is coupled to the power dissipator and controls its conductance and dissipation and is also connected to the solar cells in a power taping relationship to derive operating power therefrom. An error signal generator is coupled to the load bus and to a reference signal generator to provide an error output signal which is representative of the difference between the electric parameters existing at the load bus and the reference signal generator. An error amplifier is coupled to the error signal generator and the dissipation driver to provide the driver with controlling signals.

mTOR-Notch3 signaling mediates pulmonary hypertension in hypoxia-exposed neonatal rats independent of changes in autophagy.

PubMed

Ivanovska, Julijana; Shah, Sparsh; Wong, Mathew J; Kantores, Crystal; Jain, Amish; Post, Martin; Yeganeh, Behzad; Jankov, Robert P

2017-11-01

Mammalian target of rapamycin (mTOR) is a pivotal regulator of cell proliferation, survival, and autophagy. Autophagy is increased in adult experimental chronic pulmonary hypertension (PHT), but its contributory role to pulmonary vascular disease remains uncertain and has yet to be explored in the neonatal animal. Notch is a major pro-proliferative pathway activated by mTOR. A direct relationship between autophagy and Notch signaling has not been previously explored. Our aim was to examine changes in mTOR-, Notch-, and autophagy-related pathways and the therapeutic effects of autophagy modulators in experimental chronic neonatal PHT secondary to chronic hypoxia. Rat pups were exposed to normoxia or hypoxia (13% O 2 ) from postnatal days 1-21, while receiving treatment with temsirolimus (mTOR inhibitor), DAPT (Notch inhibitor), or chloroquine (inhibitor of autophagic flux). Exposure to hypoxia up-regulated autophagy and Notch3 signaling markers in lung, pulmonary artery (PA), and PA-derived smooth muscle cells (SMCs). Temsirolimus prevented chronic PHT and attenuated PA and SMC signaling secondary to hypoxia. These effects were replicated by DAPT. mTOR or Notch inhibition also down-regulated smooth muscle content of platelet-derived growth factor β-receptor, a known contributor to vascular remodeling. In contrast, chloroquine had no modifying effects on markers of chronic PHT. Knockdown of Beclin-1 in SMCs had no effect on hypoxia-stimulated Notch3 signaling. mTOR-Notch3 signaling plays a critical role in experimental chronic neonatal PHT. Inhibition of autophagy did not suppress Notch signaling and had no effect on markers of chronic PHT. © 2017 Wiley Periodicals, Inc.

MYC2 Differentially Modulates Diverse Jasmonate-Dependent Functions in Arabidopsis[W

PubMed Central

Dombrecht, Bruno; Xue, Gang Ping; Sprague, Susan J.; Kirkegaard, John A.; Ross, John J.; Reid, James B.; Fitt, Gary P.; Sewelam, Nasser; Schenk, Peer M.; Manners, John M.; Kazan, Kemal

2007-01-01

The Arabidopsis thaliana basic helix-loop-helix Leu zipper transcription factor (TF) MYC2/JIN1 differentially regulates jasmonate (JA)-responsive pathogen defense (e.g., PDF1.2) and wound response (e.g., VSP) genes. In this study, genome-wide transcriptional profiling of wild type and mutant myc2/jin1 plants followed by functional analyses has revealed new roles for MYC2 in the modulation of diverse JA functions. We found that MYC2 negatively regulates Trp and Trp-derived secondary metabolism such as indole glucosinolate biosynthesis during JA signaling. Furthermore, MYC2 positively regulates JA-mediated resistance to insect pests, such as Helicoverpa armigera, and tolerance to oxidative stress, possibly via enhanced ascorbate redox cycling and flavonoid biosynthesis. Analyses of MYC2 cis binding elements and expression of MYC2-regulated genes in T-DNA insertion lines of a subset of MYC2–regulated TFs suggested that MYC2 might modulate JA responses via differential regulation of an intermediate spectrum of TFs with activating or repressing roles in JA signaling. MYC2 also negatively regulates its own expression, and this may be one of the mechanisms used in fine-tuning JA signaling. Overall, these results provide new insights into the function of MYC2 and the transcriptional coordination of the JA signaling pathway. PMID:17616737

RhoA regulates Activin B-induced stress fiber formation and migration of bone marrow-derived mesenchymal stromal cell through distinct signaling.

PubMed

Wang, Xueer; Tang, Pei; Guo, Fukun; Zhang, Min; Chen, Yinghua; Yan, Yuan; Tian, Zhihui; Xu, Pengcheng; Zhang, Lei; Zhang, Lu; Zhang, Lin

2017-01-01

In our previous study, Activin B induced actin stress fiber formation and cell migration in Bone marrow-derived mesenchymal stem cells (BMSCs) in vitro. However, the underlying molecular mechanisms are not well studied. RhoA is recognized to play a critical role in the regulation of actomyosin cytoskeletal organization and cell migration. Pull-down assay was performed to investigate the activity of RhoA. The dominant-negative mutants of RhoA (RhoA(N19)) was used to determine whether RhoA has a role in Activin B-induced cytoskeleton organization and cell migration in BMSCs. Cytoskeleton organization was examined by fluorescence Rhodamine-phalloidin staining, and cell migration by transwell and cell scratching assay. Western blot was carried out to investigate downstream signaling cascade of RhoA. Inhibitor and siRNAs were used to detect the role of downstream signaling in stress fiber formation and/or cell migration. RhoA was activated by Activin B in BMSCs. RhoA(N19) blocked Activin B-induced stress fiber formation and cell migration. ROCK inhibitor blocked Activin B-induced stress fiber formation but enhanced BMSCs migration. Activin B induced phosphorylation of LIMK2 and Cofilin, which was abolished by ROCK inhibition. Both of siRNA LIMK2 and siRNA Cofilin inhibited Activin B-induced stress fiber formation. RhoA regulates Activin B-induced stress fiber formation and migration of BMSCs. A RhoA-ROCK-LIMK2-Cofilin signaling node exists and regulates actin stress fiber formation. RhoA regulates Activin B-induced cell migration independent of ROCK. Better understanding of the molecular mechanisms of BMSCs migration will help optimize therapeutic strategy to target BMSCs at injured tissues. Copyright © 2016 Elsevier B.V. All rights reserved.

Endothelial miR-17∼92 cluster negatively regulates arteriogenesis via miRNA-19 repression of WNT signaling.

PubMed

Landskroner-Eiger, Shira; Qiu, Cong; Perrotta, Paola; Siragusa, Mauro; Lee, Monica Y; Ulrich, Victoria; Luciano, Amelia K; Zhuang, Zhen W; Corti, Federico; Simons, Michael; Montgomery, Rusty L; Wu, Dianqing; Yu, Jun; Sessa, William C

2015-10-13

The contribution of endothelial-derived miR-17∼92 to ischemia-induced arteriogenesis has not been investigated in an in vivo model. In the present study, we demonstrate a critical role for the endothelial-derived miR-17∼92 cluster in shaping physiological and ischemia-triggered arteriogenesis. Endothelial-specific deletion of miR-17∼92 results in an increase in collateral density limbs and hearts and in ischemic limbs compared with control mice, and consequently improves blood flow recovery. Individual cluster components positively or negatively regulate endothelial cell (EC) functions in vitro, and, remarkably, ECs lacking the cluster spontaneously form cords in a manner rescued by miR-17a, -18a, and -19a. Using both in vitro and in vivo analyses, we identified FZD4 and LRP6 as targets of miR-19a/b. Both of these targets were up-regulated in 17∼92 KO ECs compared with control ECs, and both were shown to be targeted by miR-19 using luciferase assays. We demonstrate that miR-19a negatively regulates FZD4, its coreceptor LRP6, and WNT signaling, and that antagonism of miR-19a/b in aged mice improves blood flow recovery after ischemia and reduces repression of these targets. Collectively, these data provide insights into miRNA regulation of arterialization and highlight the importance of vascular WNT signaling in maintaining arterial blood flow.

Food-derived sensory cues modulate longevity via distinct neuroendocrine insulin-like peptides

PubMed Central

Artan, Murat; Jeong, Dae-Eun; Lee, Dongyeop; Kim, Young-Il; Son, Heehwa G.; Husain, Zahabiya; Kim, Jinmahn; Altintas, Ozlem; Kim, Kyuhyung; Alcedo, Joy; Lee, Seung-Jae V.

2016-01-01

Environmental fluctuations influence organismal aging by affecting various regulatory systems. One such system involves sensory neurons, which affect life span in many species. However, how sensory neurons coordinate organismal aging in response to changes in environmental signals remains elusive. Here, we found that a subset of sensory neurons shortens Caenorhabditis elegans’ life span by differentially regulating the expression of a specific insulin-like peptide (ILP), INS-6. Notably, treatment with food-derived cues or optogenetic activation of sensory neurons significantly increases ins-6 expression and decreases life span. INS-6 in turn relays the longevity signals to nonneuronal tissues by decreasing the activity of the transcription factor DAF-16/FOXO. Together, our study delineates a mechanism through which environmental sensory cues regulate aging rates by modulating the activities of specific sensory neurons and ILPs. PMID:27125673

Redox regulation of electrophilic signaling by reactive persulfides in cardiac cells.

PubMed

Nishida, Motohiro; Nishimura, Akiyuki; Matsunaga, Tetsuro; Motohashi, Hozumi; Kasamatsu, Shingo; Akaike, Takaaki

2017-08-01

Maintaining a redox balance by means of precisely controlled systems that regulate production, and elimination, and metabolism of electrophilic substances (electrophiles) is essential for normal cardiovascular function. Electrophilic signaling is mainly regulated by endogenous electrophiles that are generated from reactive oxygen species, nitric oxide, and the derivative reactive species of nitric oxide during stress responses, as well as by exogenous electrophiles including compounds in foods and environmental pollutants. Among electrophiles formed endogenously, 8-nitroguanosine 3',5'-cyclic monophosphate (8-nitro-cGMP) has unique cell signaling functions, and pathways for its biosynthesis, signaling mechanism, and metabolism in cells have been clarified. Reactive persulfide species such as cysteine persulfides and polysulfides that are endogenously produced in cells are likely to be involved in 8-nitro-cGMP metabolism. These new aspects of redox biology may stimulate innovative and multidisciplinary research in cardiovascular physiology and pathophysiology. In our review, we focus on the redox-dependent regulation of electrophilic signaling via reduction and metabolism of electrophiles by reactive persulfides in cardiac cells, and we include suggestions for a new therapeutic strategy for cardiovascular disease. Copyright © 2017 Elsevier Inc. All rights reserved.

[Wnt/β-catenin pathway involved in the regulation of rat mesangial cell proliferation by adipose-derived mesenchymal stem cells].

PubMed

Li, Zhi; Zhang, Mengying; Li, Xueqin; Lu, Jinming; Xu, Liang

2016-11-01

Objective To investigate the effect of adipose-derived mesenchymal stem cells (ADSCs) on glomerular mesangial cell proliferation via Wnt/β-catenin pathway. Methods The rat glomerular mesangial cells (HBZY-1) were incubated in conditioned ADSC medium. Cell cycle was analyzed with flow cytometry; the proliferation rate of HBZY-1 and the expression levels of relative genes and proteins of Wnt signaling pathway were measured using RNA interference, quantitative real-time PCR and Western blotting, respectively. Results HBZY-1 proliferation was significantly inhibited under the action of conditioned ADSC medium, whereas dickkopf WNT signaling pathway inhibitor 1 (DKK1) mRNA level was up-regulated. Fibronectin and TGF-β1 mRNA expression as well as β-catenin and Bcl-2 protein levels of HBZY-1 were significantly down-regulated. DKK1 gene expression level in ADSCs was significantly higher than that of HBZY-1. After RNA interference, DKK1 expression level in ADSCs was markedly inhibited, yet the β-catenin protein level was notably elevated. The β-catenin and Bcl-2 protein levels of HBZY-1 were also significantly raised in HBZY-1 after cultured with conditioned medium containing ADSCs treated with RNA interference. Conclusion Wnt/β-catenin may be a potential signaling pathway involved in the regulative effect of ADSCs on glomerular mesangial cell proliferation.

The role of heparins and nano-heparins as therapeutic tool in breast cancer.

PubMed

Afratis, Nikos A; Karamanou, Konstantina; Piperigkou, Zoi; Vynios, Demitrios H; Theocharis, Achilleas D

2017-06-01

Glycosaminoglycans are integral part of the dynamic extracellular matrix (ECM) network that control crucial biochemical and biomechanical signals required for tissue morphogenesis, differentiation, homeostasis and cancer development. Breast cancer cells communicate with stromal ones to modulate ECM mainly through release of soluble effectors during cancer progression. The intracellular cross-talk between cell surface receptors and estrogen receptors is important for the regulation of breast cancer cell properties and production of ECM molecules. In turn, reorganized ECM-cell surface interface modulates signaling cascades, which regulate almost all aspects of breast cell behavior. Heparan sulfate chains present on cell surface and matrix proteoglycans are involved in regulation of breast cancer functions since they are capable of binding numerous matrix molecules, growth factors and inflammatory mediators thus modulating their signaling. In addition to its anticoagulant activity, there is accumulating evidence highlighting various anticancer activities of heparin and nano-heparin derivatives in numerous types of cancer. Importantly, heparin derivatives significantly reduce breast cancer cell proliferation and metastasis in vitro and in vivo models as well as regulates the expression profile of major ECM macromolecules, providing strong evidence for therapeutic targeting. Nano-formulations of the glycosaminoglycan heparin are possibly novel tools for targeting tumor microenvironment. In this review, the role of heparan sulfate/heparin and its nano-formulations in breast cancer biology are presented and discussed in terms of future pharmacological targeting.

Regulation of Cellular Communication by Signaling Microdomains in the Blood Vessel Wall

PubMed Central

Billaud, Marie; Lohman, Alexander W.; Johnstone, Scott R.; Biwer, Lauren A.; Mutchler, Stephanie; Isakson, Brant E.

2014-01-01

It has become increasingly clear that the accumulation of proteins in specific regions of the plasma membrane can facilitate cellular communication. These regions, termed signaling microdomains, are found throughout the blood vessel wall where cellular communication, both within and between cell types, must be tightly regulated to maintain proper vascular function. We will define a cellular signaling microdomain and apply this definition to the plethora of means by which cellular communication has been hypothesized to occur in the blood vessel wall. To that end, we make a case for three broad areas of cellular communication where signaling microdomains could play an important role: 1) paracrine release of free radicals and gaseous molecules such as nitric oxide and reactive oxygen species; 2) role of ion channels including gap junctions and potassium channels, especially those associated with the endothelium-derived hyperpolarization mediated signaling, and lastly, 3) mechanism of exocytosis that has considerable oversight by signaling microdomains, especially those associated with the release of von Willebrand factor. When summed, we believe that it is clear that the organization and regulation of signaling microdomains is an essential component to vessel wall function. PMID:24671377

Regulation of cellular communication by signaling microdomains in the blood vessel wall.

PubMed

Billaud, Marie; Lohman, Alexander W; Johnstone, Scott R; Biwer, Lauren A; Mutchler, Stephanie; Isakson, Brant E

2014-01-01

It has become increasingly clear that the accumulation of proteins in specific regions of the plasma membrane can facilitate cellular communication. These regions, termed signaling microdomains, are found throughout the blood vessel wall where cellular communication, both within and between cell types, must be tightly regulated to maintain proper vascular function. We will define a cellular signaling microdomain and apply this definition to the plethora of means by which cellular communication has been hypothesized to occur in the blood vessel wall. To that end, we make a case for three broad areas of cellular communication where signaling microdomains could play an important role: 1) paracrine release of free radicals and gaseous molecules such as nitric oxide and reactive oxygen species; 2) role of ion channels including gap junctions and potassium channels, especially those associated with the endothelium-derived hyperpolarization mediated signaling, and lastly, 3) mechanism of exocytosis that has considerable oversight by signaling microdomains, especially those associated with the release of von Willebrand factor. When summed, we believe that it is clear that the organization and regulation of signaling microdomains is an essential component to vessel wall function.

A Microbial Drugstore for Motility.

PubMed

Cryan, John F; Clarke, Gerard; Dinan, Timothy G; Schellekens, Harriet

2018-06-13

While there is growing appreciation that the microbiome regulates gut-brain signaling, the underlying mechanisms remain elusive. In this issue of Cell Host & Microbe, Bhattarai et al. (2018) identify bacteria-derived tryptamine as a ligand for the gut-epithelium-expressed GPCR 5-HT4 receptor, thereby functioning as a regulator of gastrointestinal motility. Copyright © 2018 Elsevier Inc. All rights reserved.

Bile Acid Metabolism and Signaling

PubMed Central

Chiang, John Y. L.

2015-01-01

Bile acids are important physiological agents for intestinal nutrient absorption and biliary secretion of lipids, toxic metabolites, and xenobiotics. Bile acids also are signaling molecules and metabolic regulators that activate nuclear receptors and G protein-coupled receptor (GPCR) signaling to regulate hepatic lipid, glucose, and energy homeostasis and maintain metabolic homeostasis. Conversion of cholesterol to bile acids is critical for maintaining cholesterol homeostasis and preventing accumulation of cholesterol, triglycerides, and toxic metabolites, and injury in the liver and other organs. Enterohepatic circulation of bile acids from the liver to intestine and back to the liver plays a central role in nutrient absorption and distribution, and metabolic regulation and homeostasis. This physiological process is regulated by a complex membrane transport system in the liver and intestine regulated by nuclear receptors. Toxic bile acids may cause inflammation, apoptosis, and cell death. On the other hand, bile acid-activated nuclear and GPCR signaling protects against inflammation in liver, intestine, and macrophages. Disorders in bile acid metabolism cause cholestatic liver diseases, dyslipidemia, fatty liver diseases, cardiovascular diseases, and diabetes. Bile acids, bile acid derivatives, and bile acid sequestrants are therapeutic agents for treating chronic liver diseases, obesity, and diabetes in humans. PMID:23897684

ADHD-Derived Coding Variation in the Dopamine Transporter Disrupts Microdomain Targeting and Trafficking Regulation

PubMed Central

Sakrikar, Dhananjay; Mazei-Robison, Michelle S.; Mergy, Marc A.; Richtand, Nathan W.; Han, Qiao; Hamilton, Peter J.; Bowton, Erica; Galli, Aurelio; Veenstra-VanderWeele, Jeremy; Gill, Michael; Blakely, Randy D.

2012-01-01

Attention-Deficit Hyperactivity Disorder (ADHD) is the most commonly diagnosed disorder of school-age children. Although genetic and brain imaging studies suggest a contribution of altered dopamine (DA) signaling in ADHD, evidence of signaling perturbations contributing to risk is largely circumstantial. The presynaptic, cocaine and amphetamine (AMPH)-sensitive DA transporter (DAT) constrains DA availability at pre- and post-synaptic receptors following vesicular release and is targeted by the most commonly prescribed ADHD therapeutics. Using polymorphism discovery approaches with an ADHD cohort, we identified a human DAT (hDAT) coding variant, R615C, located in the transporter’s distal C-terminus, a region previously implicated in constitutive and regulated transporter trafficking. Here we demonstrate that whereas wildtype DAT proteins traffic in a highly regulated manner, DAT 615C proteins recycle constitutively, and demonstrate insensitivity to the endocytic effects of AMPH and protein kinase C (PKC) activation. The disrupted regulation of DAT 615C parallels a redistribution of the transporter variant away from GM1 ganglioside- and flotillin1-enriched membranes, and is accompanied by altered calcium/calmodulin-dependent protein kinase II (CaMKII) and flotillin-1 interactions. Using C-terminal peptides derived from wildtype DAT and the R615C variant, we establish that the DAT 615C C-terminus can act dominantly to preclude AMPH regulation of wildtype DAT. Mutagenesis of DAT C-terminal sequences suggest that phosphorylation of T613 may be important in sorting DAT between constitutive and regulated pathways. Together, our studies support a coupling of DAT microdomain localization with transporter regulation and provide evidence of perturbed DAT activity and DA signaling as a risk determinant for ADHD. PMID:22514303

Control of energy balance by hypothalamic gene circuitry involving two nuclear receptors, neuron-derived orphan receptor 1 and glucocorticoid receptor.

PubMed

Kim, Sun-Gyun; Lee, Bora; Kim, Dae-Hwan; Kim, Juhee; Lee, Seunghee; Lee, Soo-Kyung; Lee, Jae W

2013-10-01

Nuclear receptors (NRs) regulate diverse physiological processes, including the central nervous system control of energy balance. However, the molecular mechanisms for the central actions of NRs in energy balance remain relatively poorly defined. Here we report a hypothalamic gene network involving two NRs, neuron-derived orphan receptor 1 (NOR1) and glucocorticoid receptor (GR), which directs the regulated expression of orexigenic neuropeptides agouti-related peptide (AgRP) and neuropeptide Y (NPY) in response to peripheral signals. Our results suggest that the anorexigenic signal leptin induces NOR1 expression likely via the transcription factor cyclic AMP response element-binding protein (CREB), while the orexigenic signal glucocorticoid mobilizes GR to inhibit NOR1 expression by antagonizing the action of CREB. Also, NOR1 suppresses glucocorticoid-dependent expression of AgRP and NPY. Consistently, relative to wild-type mice, NOR1-null mice showed significantly higher levels of AgRP and NPY and were less responsive to leptin in decreasing the expression of AgRP and NPY. These results identify mutual antagonism between NOR1 and GR to be a key rheostat for peripheral metabolic signals to centrally control energy balance.

Consequences of endogenous and exogenous WNT signaling for development of the preimplantation bovine embryo.

PubMed

Tribulo, Paula; Leão, Beatriz Caetano da Silva; Lehloenya, Khoboso C; Mingoti, Gisele Zoccal; Hansen, Peter J

2017-06-01

The specific role of WNT signaling during preimplantation development remains unclear. Here, we evaluated consequences of activation and inhibition of β-catenin (CTNNB1)-dependent and -independent WNT signaling in the bovine preimplantation embryo. Activation of CTNNB1-mediated WNT signaling by the agonist 2-amino-4-(3,4-(methylenedioxy)benzylamino)-6-(3-methoxyphenyl)pyrimidine (AMBMP) and a glycogen synthase kinase 3 inhibitor reduced development to the blastocyst stage. Moreover, the antagonist of WNT signaling, dickkopf-related protein 1 (DKK1), alleviated the negative effect of AMBMP on development via reduction of CTNNB1. Based on labeling for phospho c-Jun N-terminal kinase, there was no evidence that DKK1 activated the planar cell polarity (PCP) pathway. Inhibition of secretion of endogenous WNTs did not affect development but increased number of cells in the inner cell mass (ICM). In contrast, DKK1 did not affect number of ICM or trophectoderm (TE) cells, suggesting that embryo-derived WNTs regulate ICM proliferation through a mechanism independent of CTNNB1. In addition, DKK1 did not affect the number of cells positive for the transcription factor yes-associated protein 1 (YAP1) involved in TE formation. In fact, DKK1 decreased YAP1. In contrast, exposure of embryos to WNT family member 7A (WNT7A) improved blastocyst development, inhibited the PCP pathway, and did not affect amounts of CTNNB1. Results indicate that embryo-derived WNTs are dispensable for blastocyst formation but participate in regulation of ICM proliferation, likely through a mechanism independent of CTNNB1. The response to AMBMP and WNT7A leads to the hypothesis that maternally derived WNTs can play a positive or negative role in regulation of preimplantation development. © The Authors 2017. Published by Oxford University Press on behalf of Society for the Study of Reproduction.

Stromal derived factor-1 regulates bone morphogenetic protein 2-induced osteogenic differentiation of primary mesenchymal stem cells

PubMed Central

Hosogane, Naobumi; Huang, Zhiping; Rawlins, Bernard A.; Liu, Xia; Boachie-Adjei, Oheneba; Boskey, Adele L.; Zhu, Wei

2010-01-01

Stromal derived factor-1 (SDF-1) is a chemokine signaling molecule that binds to its transmembrane receptor CXC chemokine receptor-4 (CXCR4). While we previously detected that SDF-1 was co-required with bone morphogenetic protein 2 (BMP2) for differentiating mesenchymal C2C12 cells into osteoblastic cells, it is unknown whether SDF-1 is similarly involved in the osteogenic differentiation of mesenchymal stem cells (MSCs). Therefore, here we examined the role of SDF-1 signaling during BMP2-induced osteogenic differentiation of primary MSCs that were derived from human and mouse bone marrow. Our data showed that blocking of the SDF-1/CXCR4 signal axis or adding SDF-1 protein to MSCs significantly affected BMP2-induced alkaline phosphatase (ALP) activity and osteocalcin (OCN) synthesis, markers of preosteoblasts and mature osteoblasts, respectively. Moreover, disrupting the SDF-1 signaling impaired bone nodule mineralization during terminal differentiation of MSCs. Furthermore, we detected that blocking of the SDF-1 signaling inhibited the BMP2-induced early expression of Runt-related factor-2 (Runx2) and osterix (Osx), two “master” regulators of osteogenesis, and the SDF-1 effect was mediated via intracellular Smad and Erk activation. In conclusion, our results demonstrated a regulatory role of SDF-1 in BMP2-induced osteogenic differentiation of MSCs, as perturbing the SDF-1 signaling affected the differentiation of MSCs towards osteoblastic cells in response to BMP2 stimulation. These data provide novel insights into molecular mechanisms underlying MSC osteogenesis, and will contribute to the development of MSC therapies for enhancing bone formation and regeneration in broad orthopaedic situations. PMID:20362069

Wnt/Yes-Associated Protein Interactions During Neural Tissue Patterning of Human Induced Pluripotent Stem Cells.

PubMed

Bejoy, Julie; Song, Liqing; Zhou, Yi; Li, Yan

2018-04-01

Human induced pluripotent stem cells (hiPSCs) have special ability to self-assemble into neural spheroids or mini-brain-like structures. During the self-assembly process, Wnt signaling plays an important role in regional patterning and establishing positional identity of hiPSC-derived neural progenitors. Recently, the role of Wnt signaling in regulating Yes-associated protein (YAP) expression (nuclear or cytoplasmic), the pivotal regulator during organ growth and tissue generation, has attracted increasing interests. However, the interactions between Wnt and YAP expression for neural lineage commitment of hiPSCs remain poorly explored. The objective of this study is to investigate the effects of Wnt signaling and YAP expression on the cellular population in three-dimensional (3D) neural spheroids derived from hiPSCs. In this study, Wnt signaling was activated using CHIR99021 for 3D neural spheroids derived from human iPSK3 cells through embryoid body formation. Our results indicate that Wnt activation induces nuclear localization of YAP and upregulates the expression of HOXB4, the marker for hindbrain/spinal cord. By contrast, the cells exhibit more rostral forebrain neural identity (expression of TBR1) without Wnt activation. Cytochalasin D was then used to induce cytoplasmic YAP and the results showed the decreased HOXB4 expression. In addition, the incorporation of microparticles in the neural spheroids was investigated for the perturbation of neural patterning. This study may indicate the bidirectional interactions of Wnt signaling and YAP expression during neural tissue patterning, which have the significance in neurological disease modeling, drug screening, and neural tissue regeneration.

The Crossroads of Synaptic Growth Signaling, Membrane Traffic and Neurological Disease: Insights from Drosophila.

PubMed

Deshpande, Mugdha; Rodal, Avital A

2016-02-01

Neurons require target-derived autocrine and paracrine growth factors to maintain proper identity, innervation, homeostasis and survival. Neuronal growth factor signaling is highly dependent on membrane traffic, both for the packaging and release of the growth factors themselves, and for regulation of intracellular signaling by their transmembrane receptors. Here, we review recent findings from the Drosophila larval neuromuscular junction (NMJ) that illustrate how specific steps of intracellular traffic and inter-organelle interactions impinge on signaling, particularly in the bone morphogenic protein, Wingless and c-Jun-activated kinase pathways, regulating elaboration and stability of NMJ arbors, construction of synapses and synaptic transmission and homeostasis. These membrane trafficking and signaling pathways have been implicated in human motor neuron diseases including amyotrophic lateral sclerosis and hereditary spastic paraplegia, highlighting their importance for neuronal health and survival. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Mitogen-activated protein kinase phosphatase 1 (MKP-1) in macrophage biology and cardiovascular disease. A redox-regulated master controller of monocyte function and macrophage phenotype.

PubMed

Kim, Hong Seok; Asmis, Reto

2017-08-01

MAPK pathways play a critical role in the activation of monocytes and macrophages by pathogens, signaling molecules and environmental cues and in the regulation of macrophage function and plasticity. MAPK phosphatase 1 (MKP-1) has emerged as the main counter-regulator of MAPK signaling in monocytes and macrophages. Loss of MKP-1 in monocytes and macrophages in response to metabolic stress leads to dysregulation of monocyte adhesion and migration, and gives rise to dysfunctional, proatherogenic monocyte-derived macrophages. Here we review the properties of this redox-regulated dual-specificity MAPK phosphatase and the role of MKP-1 in monocyte and macrophage biology and cardiovascular diseases. Copyright © 2017 Elsevier Inc. All rights reserved.

Molecular Mechanisms of Fibroblast Growth Factor Signaling in Physiology and Pathology

PubMed Central

Belov, Artur A.; Mohammadi, Moosa

2013-01-01

Fibroblast growth factors (FGFs) signal in a paracrine or endocrine fashion to mediate a myriad of biological activities, ranging from issuing developmental cues, maintaining tissue homeostasis, and regulating metabolic processes. FGFs carry out their diverse functions by binding and dimerizing FGF receptors (FGFRs) in a heparan sulfate (HS) cofactor- or Klotho coreceptor-assisted manner. The accumulated wealth of structural and biophysical data in the past decade has transformed our understanding of the mechanism of FGF signaling in human health and development, and has provided novel concepts in receptor tyrosine kinase (RTK) signaling. Among these contributions are the elucidation of HS-assisted receptor dimerization, delineation of the molecular determinants of ligand–receptor specificity, tyrosine kinase regulation, receptor cis-autoinhibition, and tyrosine trans-autophosphorylation. These structural studies have also revealed how disease-associated mutations highjack the physiological mechanisms of FGFR regulation to contribute to human diseases. In this paper, we will discuss the structurally and biophysically derived mechanisms of FGF signaling, and how the insights gained may guide the development of therapies for treatment of a diverse array of human diseases. PMID:23732477

Molecular mechanisms of fibroblast growth factor signaling in physiology and pathology.

PubMed

Belov, Artur A; Mohammadi, Moosa

2013-06-01

Fibroblast growth factors (FGFs) signal in a paracrine or endocrine fashion to mediate a myriad of biological activities, ranging from issuing developmental cues, maintaining tissue homeostasis, and regulating metabolic processes. FGFs carry out their diverse functions by binding and dimerizing FGF receptors (FGFRs) in a heparan sulfate (HS) cofactor- or Klotho coreceptor-assisted manner. The accumulated wealth of structural and biophysical data in the past decade has transformed our understanding of the mechanism of FGF signaling in human health and development, and has provided novel concepts in receptor tyrosine kinase (RTK) signaling. Among these contributions are the elucidation of HS-assisted receptor dimerization, delineation of the molecular determinants of ligand-receptor specificity, tyrosine kinase regulation, receptor cis-autoinhibition, and tyrosine trans-autophosphorylation. These structural studies have also revealed how disease-associated mutations highjack the physiological mechanisms of FGFR regulation to contribute to human diseases. In this paper, we will discuss the structurally and biophysically derived mechanisms of FGF signaling, and how the insights gained may guide the development of therapies for treatment of a diverse array of human diseases.

Cinnamon extract regulates plasma levels of adipose-derived factors and expression of multiple genes related to carbohydrate metabolism and lipogenesis in adipose tissue of fructose-fed rats

USDA-ARS?s Scientific Manuscript database

We reported previously that a dietary cinnamon extract (CE) improves systemic insulin sensitivity and dyslipidemia by enhancing insulin signaling. In the present study, we examined the effects of CE on several biomarkers including plasma levels of adipose-derived adipokines, and the potential molec...

Associations among the cecal microbiome and bacterially-derived cecal xeno-metabolites during diabetes progression in the UC Davis-Type 2 diabetes rat model

USDA-ARS?s Scientific Manuscript database

The gut microbiome is altered in obesity and diabetes, but the molecular signals linking gut microbes and host metabolic regulation have not been established. Our aim was to identify gut microbe-derived xeno-metabolites that associate with alterations in the microbiome during the progression of a t...

Therapeutic charm of quercetin and its derivatives: a review of research and patents.

PubMed

Sharma, Ajay; Kashyap, Dharambir; Sak, Katrin; Tuli, Hardeep Singh; Sharma, Anil K

2018-01-01

Bioactive polyphenolic compounds derived from plants are being utilized for prevention of various chronic diseases including cancer and cardiovascular disorders. Quercetin, a potential poly-phenolic flavonol, found in onions, apples and berries, has been implicated against cancer proliferation, chronic inflammation and various other oxidative manifestations. Evidences suggested that quercetin negatively regulates the numerous crucial signaling pathways associated with life-threatening diseases. Major signaling pathways including NF-κB, MAPK, PI3K-AKT and mTOR are found to be regulated by quercetin. In addition, several patents have reported recently on quercetin derivatives describing wide therapeutic applications such as anticancer/antiproliferatory, antioxidative/antiaging, antiviral, anti-inflammatory, cardioprotective. Present review emphasizes the chemistry and sources of quercetin followed by description of its broad-spectrum therapeutic potential along with proposed mechanisms of action. Furthermore, this review also highlights the important modifications in the basic chemical structure of quercetin in terms of published patents. Insolubility of the bioactive compounds restricts their medicinal importance which could be overcome by modifications in the chemical structure of so-called derivatives. Most of the patents deal with the modifications in chemical structure of quercetin mainly at hydroxyl groups and C-6 and C-7 positions.

Bmp signaling regulates a dose-dependent transcriptional program to control facial skeletal development.

PubMed

Bonilla-Claudio, Margarita; Wang, Jun; Bai, Yan; Klysik, Elzbieta; Selever, Jennifer; Martin, James F

2012-02-01

We performed an in depth analysis of Bmp4, a critical regulator of development, disease, and evolution, in cranial neural crest (CNC). Conditional Bmp4 overexpression, using a tetracycline-regulated Bmp4 gain-of-function allele, resulted in facial skeletal changes that were most dramatic after an E10.5 Bmp4 induction. Expression profiling uncovered a signature of Bmp4-induced genes (BIG) composed predominantly of transcriptional regulators that control self-renewal, osteoblast differentiation and negative Bmp autoregulation. The complimentary experiment, CNC inactivation of Bmp2, Bmp4 and Bmp7, resulted in complete or partial loss of multiple CNC-derived skeletal elements, revealing a crucial requirement for Bmp signaling in membranous bone and cartilage development. Importantly, the BIG signature was reduced in Bmp loss-of-function mutants, indicating Bmp-regulated target genes are modulated by Bmp dose. Chromatin immunoprecipitation (ChIP) revealed a subset of the BIG signature, including Satb2, Smad6, Hand1, Gadd45γ and Gata3, that was bound by Smad1/5 in the developing mandible, revealing direct Smad-mediated regulation. These data support the hypothesis that Bmp signaling regulates craniofacial skeletal development by balancing self-renewal and differentiation pathways in CNC progenitors.

Chromatin organization regulated by EZH2-mediated H3K27me3 is required for OPN-induced migration of bone marrow-derived mesenchymal stem cells.

PubMed

Liu, Lingling; Luo, Qing; Sun, Jinghui; Ju, Yang; Morita, Yasuyuki; Song, Guanbin

2018-03-01

Osteopontin (OPN) is a chemokine-like extracellular matrix-associated protein involved in the migration of bone marrow-derived mesenchymal stem cells (BMSCs). An increasing number of studies have found that chromatin organization may affect cellular migration. However, whether OPN regulates chromatin organization is not understood, nor are the underlying molecular mechanisms. In this study, we investigated the link between chromatin organization and BMSC migration and demonstrated that OPN-mediated BMSC migration leads to elevated levels of heterochromatin marker histone H3 lysine 27 trimethylation (H3K27me3) through the methyltransferase EZH2. The expression of EZH2 reorganizes the chromatin structure of BMSCs. Pharmacological inhibition or depletion of EZH2 blocks BMSC migration. Moreover, using an atomic force microscope (AFM), we found that chromatin decondensation alters the mechanical properties of the nucleus. In addition, inhibition of extracellular signal-regulated kinase 1/2 (ERK1/2) signals represses OPN-promoted chromatin condensation and cell migration. Thus, our results identify a mechanism by which ERK1/2 signalling drives specific chromatin modifications in BMSCs, which alters chromatin organization and thereby enables OPN-mediated BMSC migration. Copyright © 2018 Elsevier Ltd. All rights reserved.

TEAD and YAP regulate the enhancer network of human embryonic pancreatic progenitors.

PubMed

Cebola, Inês; Rodríguez-Seguí, Santiago A; Cho, Candy H-H; Bessa, José; Rovira, Meritxell; Luengo, Mario; Chhatriwala, Mariya; Berry, Andrew; Ponsa-Cobas, Joan; Maestro, Miguel Angel; Jennings, Rachel E; Pasquali, Lorenzo; Morán, Ignasi; Castro, Natalia; Hanley, Neil A; Gomez-Skarmeta, Jose Luis; Vallier, Ludovic; Ferrer, Jorge

2015-05-01

The genomic regulatory programmes that underlie human organogenesis are poorly understood. Pancreas development, in particular, has pivotal implications for pancreatic regeneration, cancer and diabetes. We have now characterized the regulatory landscape of embryonic multipotent progenitor cells that give rise to all pancreatic epithelial lineages. Using human embryonic pancreas and embryonic-stem-cell-derived progenitors we identify stage-specific transcripts and associated enhancers, many of which are co-occupied by transcription factors that are essential for pancreas development. We further show that TEAD1, a Hippo signalling effector, is an integral component of the transcription factor combinatorial code of pancreatic progenitor enhancers. TEAD and its coactivator YAP activate key pancreatic signalling mediators and transcription factors, and regulate the expansion of pancreatic progenitors. This work therefore uncovers a central role for TEAD and YAP as signal-responsive regulators of multipotent pancreatic progenitors, and provides a resource for the study of embryonic development of the human pancreas.

Biologic consequences of Stat1-independent IFN signaling

PubMed Central

Gil, M. Pilar; Bohn, Erwin; O'Guin, Andrew K.; Ramana, Chilakamarti V.; Levine, Beth; Stark, George R.; Virgin, Herbert W.; Schreiber, Robert D.

2001-01-01

Although Stat1 is required for many IFN-dependent responses, recent work has shown that IFNγ functions independently of Stat1 to affect the growth of tumor cells or immortalized fibroblasts. We now demonstrate that both IFNγ and IFNα/β regulate proliferative responses in cells of the mononuclear phagocyte lineage derived from Stat1-null mice. Using both representational difference analysis and gene arrays, we show that IFNγ exerts its Stat1-independent actions on mononuclear phagocytes by regulating the expression of many genes. This result was confirmed by monitoring changes in expression and function of the corresponding gene products. Regulation of the expression of these genes requires the IFNγ receptor and Jak1. The physiologic relevance of IFN-dependent, Stat1-independent signaling was demonstrated by monitoring antiviral responses in Stat1-null mice. Thus, the IFN receptors engage alternative Stat1-independent signaling pathways that have important physiological consequences. PMID:11390995

Intervention of Phytohormone Pathways by Pathogen Effectors[OPEN

PubMed Central

Kazan, Kemal; Lyons, Rebecca

2014-01-01

The constant struggle between plants and microbes has driven the evolution of multiple defense strategies in the host as well as offense strategies in the pathogen. To defend themselves from pathogen attack, plants often rely on elaborate signaling networks regulated by phytohormones. In turn, pathogens have adopted innovative strategies to manipulate phytohormone-regulated defenses. Tactics frequently employed by plant pathogens involve hijacking, evading, or disrupting hormone signaling pathways and/or crosstalk. As reviewed here, this is achieved mechanistically via pathogen-derived molecules known as effectors, which target phytohormone receptors, transcriptional activators and repressors, and other components of phytohormone signaling in the host plant. Herbivores and sap-sucking insects employ obligate pathogens such as viruses, phytoplasma, or symbiotic bacteria to intervene with phytohormone-regulated defenses. Overall, an improved understanding of phytohormone intervention strategies employed by pests and pathogens during their interactions with plants will ultimately lead to the development of new crop protection strategies. PMID:24920334

Neuronal expression of glucosylceramide synthase in central nervous system regulates body weight and energy homeostasis.

PubMed

Nordström, Viola; Willershäuser, Monja; Herzer, Silke; Rozman, Jan; von Bohlen Und Halbach, Oliver; Meldner, Sascha; Rothermel, Ulrike; Kaden, Sylvia; Roth, Fabian C; Waldeck, Clemens; Gretz, Norbert; de Angelis, Martin Hrabě; Draguhn, Andreas; Klingenspor, Martin; Gröne, Hermann-Josef; Jennemann, Richard

2013-01-01

Hypothalamic neurons are main regulators of energy homeostasis. Neuronal function essentially depends on plasma membrane-located gangliosides. The present work demonstrates that hypothalamic integration of metabolic signals requires neuronal expression of glucosylceramide synthase (GCS; UDP-glucose:ceramide glucosyltransferase). As a major mechanism of central nervous system (CNS) metabolic control, we demonstrate that GCS-derived gangliosides interacting with leptin receptors (ObR) in the neuronal membrane modulate leptin-stimulated formation of signaling metabolites in hypothalamic neurons. Furthermore, ganglioside-depleted hypothalamic neurons fail to adapt their activity (c-Fos) in response to alterations in peripheral energy signals. Consequently, mice with inducible forebrain neuron-specific deletion of the UDP-glucose:ceramide glucosyltransferase gene (Ugcg) display obesity, hypothermia, and lower sympathetic activity. Recombinant adeno-associated virus (rAAV)-mediated Ugcg delivery to the arcuate nucleus (Arc) significantly ameliorated obesity, specifying gangliosides as seminal components for hypothalamic regulation of body energy homeostasis.

Mitochondrial reactive oxygen species regulate the strength of inhibitory GABA-mediated synaptic transmission

NASA Astrophysics Data System (ADS)

Accardi, Michael V.; Daniels, Bryan A.; Brown, Patricia M. G. E.; Fritschy, Jean-Marc; Tyagarajan, Shiva K.; Bowie, Derek

2014-01-01

Neuronal communication imposes a heavy metabolic burden in maintaining ionic gradients essential for action potential firing and synaptic signalling. Although cellular metabolism is known to regulate excitatory neurotransmission, it is still unclear whether the brain’s energy supply affects inhibitory signalling. Here we show that mitochondrial-derived reactive oxygen species (mROS) regulate the strength of postsynaptic GABAA receptors at inhibitory synapses of cerebellar stellate cells. Inhibition is strengthened through a mechanism that selectively recruits α3-containing GABAA receptors into synapses with no discernible effect on resident α1-containing receptors. Since mROS promotes the emergence of postsynaptic events with unique kinetic properties, we conclude that newly recruited α3-containing GABAA receptors are activated by neurotransmitter released onto discrete postsynaptic sites. Although traditionally associated with oxidative stress in neurodegenerative disease, our data identify mROS as a putative homeostatic signalling molecule coupling cellular metabolism to the strength of inhibitory transmission.

Food-derived sensory cues modulate longevity via distinct neuroendocrine insulin-like peptides.

PubMed

Artan, Murat; Jeong, Dae-Eun; Lee, Dongyeop; Kim, Young-Il; Son, Heehwa G; Husain, Zahabiya; Kim, Jinmahn; Altintas, Ozlem; Kim, Kyuhyung; Alcedo, Joy; Lee, Seung-Jae V

2016-05-01

Environmental fluctuations influence organismal aging by affecting various regulatory systems. One such system involves sensory neurons, which affect life span in many species. However, how sensory neurons coordinate organismal aging in response to changes in environmental signals remains elusive. Here, we found that a subset of sensory neurons shortens Caenorhabditis elegans' life span by differentially regulating the expression of a specific insulin-like peptide (ILP), INS-6. Notably, treatment with food-derived cues or optogenetic activation of sensory neurons significantly increases ins-6 expression and decreases life span. INS-6 in turn relays the longevity signals to nonneuronal tissues by decreasing the activity of the transcription factor DAF-16/FOXO. Together, our study delineates a mechanism through which environmental sensory cues regulate aging rates by modulating the activities of specific sensory neurons and ILPs. © 2016 Artan et al.; Published by Cold Spring Harbor Laboratory Press.

Activated platelet-derived growth factor β receptor and Ras-mitogen-activated protein kinase pathway in natural bovine urinary bladder carcinomas.

PubMed

Corteggio, Annunziata; Di Geronimo, Ornella; Roperto, Sante; Roperto, Franco; Borzacchiello, Giuseppe

2012-03-01

Bovine papillomavirus types 1 or 2 (BPV-1/2) are involved in the aetiopathogenesis of bovine urinary bladder cancer. BPV-1/2 E5 activates the platelet-derived growth factor β receptor (PDGFβR). The aim of this study was to analyse the Ras/mitogen-activated protein kinase (MAPK) pathway in relation to activation of PDGFβR in natural bovine urinary bladder carcinomas. Co-immunoprecipitation and Western blot analysis demonstrated that recruitment of growth factor receptor bound protein 2 (GRB-2) and Sos-1 to the activated PDGFβR was increased in carcinomas compared to normal tissues. Higher grade bovine urinary bladder carcinomas were associated with activation of Ras, but not with activation of downstream mitogen-activated protein kinase/extracellular signal-regulated kinase (Mek 1/2) or extracellular signal-regulated kinase (Erk 1/2). Copyright © 2011 Elsevier Ltd. All rights reserved.

A cellular, molecular, and pharmacological basis for appendage regeneration in mice

PubMed Central

Leung, Thomas H.; Snyder, Emily R.; Liu, Yinghua; Wang, Jing; Kim, Seung K.

2015-01-01

Regenerative medicine aims to restore normal tissue architecture and function. However, the basis of tissue regeneration in mammalian solid organs remains undefined. Remarkably, mice lacking p21 fully regenerate injured ears without discernable scarring. Here we show that, in wild-type mice following tissue injury, stromal-derived factor-1 (Sdf1) is up-regulated in the wound epidermis and recruits Cxcr4-expressing leukocytes to the injury site. In p21-deficient mice, Sdf1 up-regulation and the subsequent recruitment of Cxcr4-expressing leukocytes are significantly diminished, thereby permitting scarless appendage regeneration. Lineage tracing demonstrates that this regeneration derives from fate-restricted progenitor cells. Pharmacological or genetic disruption of Sdf1–Cxcr4 signaling enhances tissue repair, including full reconstitution of tissue architecture and all cell types. Our findings identify signaling and cellular mechanisms underlying appendage regeneration in mice and suggest new therapeutic approaches for regenerative medicine. PMID:26494786

Strigolactones, a novel carotenoid-derived plant hormone.

PubMed

Al-Babili, Salim; Bouwmeester, Harro J

2015-01-01

Strigolactones (SLs) are carotenoid-derived plant hormones and signaling molecules. When released into the soil, SLs indicate the presence of a host to symbiotic fungi and root parasitic plants. In planta, they regulate several developmental processes that adapt plant architecture to nutrient availability. Highly branched/tillered mutants in Arabidopsis, pea, and rice have enabled the identification of four SL biosynthetic enzymes: a cis/trans-carotene isomerase, two carotenoid cleavage dioxygenases, and a cytochrome P450 (MAX1). In vitro and in vivo enzyme assays and analysis of mutants have shown that the pathway involves a combination of new reactions leading to carlactone, which is converted by a rice MAX1 homolog into an SL parent molecule with a tricyclic lactone moiety. In this review, we focus on SL biosynthesis, describe the hormonal and environmental factors that determine this process, and discuss SL transport and downstream signaling as well as the role of SLs in regulating plant development.

ANGPTL2 increases bone metastasis of breast cancer cells through enhancing CXCR4 signaling

PubMed Central

Masuda, Tetsuro; Endo, Motoyoshi; Yamamoto, Yutaka; Odagiri, Haruki; Kadomatsu, Tsuyoshi; Nakamura, Takayuki; Tanoue, Hironori; Ito, Hitoshi; Yugami, Masaki; Miyata, Keishi; Morinaga, Jun; Horiguchi, Haruki; Motokawa, Ikuyo; Terada, Kazutoyo; Morioka, Masaki Suimye; Manabe, Ichiro; Iwase, Hirotaka; Mizuta, Hiroshi; Oike, Yuichi

2015-01-01

Bone metastasis of breast cancer cells is a major concern, as it causes increased morbidity and mortality in patients. Bone tissue-derived CXCL12 preferentially recruits breast cancer cells expressing CXCR4 to bone metastatic sites. Thus, understanding how CXCR4 expression is regulated in breast cancer cells could suggest approaches to decrease bone metastasis of breast tumor cells. Here, we show that tumor cell-derived angiopoietin-like protein 2 (ANGPTL2) increases responsiveness of breast cancer cells to CXCL12 by promoting up-regulation of CXCR4 in those cells. In addition, we used a xenograft mouse model established by intracardiac injection of tumor cells to show that ANGPTL2 knockdown in breast cancer cells attenuates tumor cell responsiveness to CXCL12 by decreasing CXCR4 expression in those cells, thereby decreasing bone metastasis. Finally, we found that ANGPTL2 and CXCR4 expression levels within primary tumor tissues from breast cancer patients are positively correlated. We conclude that tumor cell-derived ANGPTL2 may increase bone metastasis by enhancing breast tumor cell responsiveness to CXCL12 signaling through up-regulation of tumor cell CXCR4 expression. These findings may suggest novel therapeutic approaches to treat metastatic breast cancer. PMID:25773070

Fasting-induced G0/G1 switch gene 2 and FGF21 expression in the liver are under regulation of adipose tissue derived fatty acids

PubMed Central

Jaeger, Doris; Schoiswohl, Gabriele; Hofer, Peter; Schreiber, Renate; Schweiger, Martina; Eichmann, Thomas O.; Pollak, Nina M.; Poecher, Nadja; Grabner, Gernot F.; Zierler, Kathrin A.; Eder, Sandra; Kolb, Dagmar; Radner, Franz P.W.; Preiss-Landl, Karina; Lass, Achim; Zechner, Rudolf; Kershaw, Erin E.; Haemmerle, Guenter

2015-01-01

Background & Aims Adipose tissue (AT)-derived fatty acids (FAs) are utilized for hepatic triacylglycerol (TG) generation upon fasting. However, their potential impact as signaling molecules is not established. Herein we examined the role of exogenous AT-derived FAs in the regulation of hepatic gene expression by investigating mice with a defect in AT-derived FA supply to the liver. Methods Plasma FA levels, tissue TG hydrolytic activities and lipid content were determined in mice lacking the lipase co-activator comparative gene identification-58 (CGI-58) selectively in AT (CGI-58-ATko) applying standard protocols. Hepatic expression of lipases, FA oxidative genes, transcription factors, ER stress markers, hormones and cytokines were determined by qRT-PCR, Western blotting and ELISA. Results Impaired AT-derived FA supply upon fasting of CGI-58-ATko mice causes a marked defect in liver PPARα-signaling and nuclear CREBH translocation. This severely reduced the expression of respective target genes such as the ATGL inhibitor G0/G1 switch gene-2 (G0S2) and the endocrine metabolic regulator FGF21. These changes could be reversed by lipid administration and raising plasma FA levels. Impaired AT-lipolysis failed to induce hepatic G0S2 expression in fasted CGI-58-ATko mice leading to enhanced ATGL-mediated TG-breakdown strongly reducing hepatic TG deposition. On high fat diet, impaired AT-lipolysis counteracts hepatic TG accumulation and liver stress linked to improved systemic insulin sensitivity. Conclusions AT-derived FAs are a critical regulator of hepatic fasting gene expression required for the induction of G0S2-expression in the liver to control hepatic TG-breakdown. Interfering with AT-lipolysis or hepatic G0S2 expression represents an effective strategy for the treatment of hepatic steatosis. PMID:25733154

Progenitors of Secondary Crest Myofibroblasts are Developmentally Committed in Early Lung Mesoderm

PubMed Central

Li, Changgong; Li, Min; Li, Sha; Xing, Yiming; Yang, Chang-Yo; Li, Aimin; Borok, Zea; De Langhe, Stijn; Minoo, Parviz

2015-01-01

Development of the mammalian lung is predicated on cross-communications between two highly interactive tissues, the endodermally-derived epithelium and the mesodermally-derived pulmonary mesenchyme. While much attention has been paid the lung epithelium, the pulmonary mesenchyme, partly due to lack of specific tractable markers remains under-investigated. The lung mesenchyme is derived from the lateral plate mesoderm and is the principal recipient of Hedgehog (Hh) signaling, a morphogenetic network that regulates multiple aspects of embryonic development. Using the Hh-responsive Gli1-creERT2 mouse line, we identified the mesodermal targets of Hh signaling at various time points during embryonic and postnatal lung development. Cell lineage analysis showed these cells serve as progenitors to contribute to multiple lineages of mesodermally-derived differentiated cell types that include parenchymal or interstitial myofibroblasts, parabronchial and perivascular smooth muscle as well as rare populations of cells within the mesothelium. Most importantly, Gli1-creERT2 identified the progenitors of secondary crest myofibroblasts, a hitherto intractable cell type that plays a key role in alveolar formation, a vital process about which little is currently known. Transcriptome analysis of Hh-targeted progenitor cells transitioning from the pseudoglandular to the saccular phase of lung development revealed important modulations of key signaling pathways. Amongst these, there was significant down-regulation of canonical WNT signaling. Ectopic stabilization of β-Catenin via inactivation of Apc by Gli1-creERT2 expanded the Hh-targeted progenitor pools, which caused the formation of fibroblastic masses within the lung parenchyma. The Gli1-creERT2 mouse line represents a novel tool in the analysis of mesenchymal cell biology and alveolar formation during lung development. PMID:25448080

Extracellular vesicles mediate signaling between the aqueous humor producing and draining cells in the ocular system

PubMed Central

Lerner, Natalie; Avissar, Sofia

2017-01-01

Purpose Canonical Wnt signaling is associated with glaucoma pathogenesis and intraocular pressure (IOP) regulation. Our goal was to gain insight into the influence of non-pigmented ciliary epithelium (NPCE)-derived exosomes on Wnt signaling by trabecular meshwork (TM) cells. The potential impact of exosomes on Wnt signaling in the ocular drainage system remains poorly understood. Methods Exosomes isolated from media collected from cultured NPCE cells by differential ultracentrifugation were characterized by dynamic light scattering (DLS), tunable resistive pulse sensing (TRPS), and nanoparticle tracking analysis (NTA), sucrose density gradient migration and transmission electron microscopy (TEM). The cellular target specificity of the NPCE-derived exosomes was investigated by confocal microscopy-based monitoring of the uptake of DiD-labeled exosomes over time, as compared to uptake by various cell lines. Changes in Wnt protein levels in TM cells induced by NPCE exosomes were evaluated by Western blot. Results Exosomes derived from NPCE cells were purified and detected as small rounded 50–140 nm membrane vesicles, as defined by DLS, NTA, TRPS and TEM. Western blot analysis indicated that the nanovesicles were positive for classic exosome markers, including Tsg101 and Alix. Isolated nanoparticles were found in sucrose density fractions typical of exosomes (1.118–1.188 g/mL sucrose). Using confocal microscopy, we demonstrated time-dependent specific accumulation of the NPCE-derived exosomes in NTM cells. Other cell lines investigated hardly revealed any exosome uptake. We further showed that exosomes induced changes in Wnt signaling protein expression in the TM cells. Western blot analysis further revealed decreased phosphorylation of GKS3β and reduced β-catenin levels. Finally, we found that treatment of NTM cells with exosomes resulted in a greater than 2-fold decrease in the level of β-catenin in the cytosolic fraction. In contrast, no remarkable difference in the amount of β-catenin in the nuclear fraction was noted, relative to the control. Conclusions The data suggest that NPCE cells release exosome-like vesicles and that these nanoparticles affect canonical Wnt signaling in TM cells. These findings may have therapeutic relevance since canonical Wnt pathway is involved in intra-ocular pressure regulation. Further understanding of NPCE-derived exosome-responsive signaling pathways may reveal new targets for pharmacological intervention within the drainage system as a target for glaucoma therapy. PMID:28241021

Extracellular vesicles mediate signaling between the aqueous humor producing and draining cells in the ocular system.

PubMed

Lerner, Natalie; Avissar, Sofia; Beit-Yannai, Elie

2017-01-01

Canonical Wnt signaling is associated with glaucoma pathogenesis and intraocular pressure (IOP) regulation. Our goal was to gain insight into the influence of non-pigmented ciliary epithelium (NPCE)-derived exosomes on Wnt signaling by trabecular meshwork (TM) cells. The potential impact of exosomes on Wnt signaling in the ocular drainage system remains poorly understood. Exosomes isolated from media collected from cultured NPCE cells by differential ultracentrifugation were characterized by dynamic light scattering (DLS), tunable resistive pulse sensing (TRPS), and nanoparticle tracking analysis (NTA), sucrose density gradient migration and transmission electron microscopy (TEM). The cellular target specificity of the NPCE-derived exosomes was investigated by confocal microscopy-based monitoring of the uptake of DiD-labeled exosomes over time, as compared to uptake by various cell lines. Changes in Wnt protein levels in TM cells induced by NPCE exosomes were evaluated by Western blot. Exosomes derived from NPCE cells were purified and detected as small rounded 50-140 nm membrane vesicles, as defined by DLS, NTA, TRPS and TEM. Western blot analysis indicated that the nanovesicles were positive for classic exosome markers, including Tsg101 and Alix. Isolated nanoparticles were found in sucrose density fractions typical of exosomes (1.118-1.188 g/mL sucrose). Using confocal microscopy, we demonstrated time-dependent specific accumulation of the NPCE-derived exosomes in NTM cells. Other cell lines investigated hardly revealed any exosome uptake. We further showed that exosomes induced changes in Wnt signaling protein expression in the TM cells. Western blot analysis further revealed decreased phosphorylation of GKS3β and reduced β-catenin levels. Finally, we found that treatment of NTM cells with exosomes resulted in a greater than 2-fold decrease in the level of β-catenin in the cytosolic fraction. In contrast, no remarkable difference in the amount of β-catenin in the nuclear fraction was noted, relative to the control. The data suggest that NPCE cells release exosome-like vesicles and that these nanoparticles affect canonical Wnt signaling in TM cells. These findings may have therapeutic relevance since canonical Wnt pathway is involved in intra-ocular pressure regulation. Further understanding of NPCE-derived exosome-responsive signaling pathways may reveal new targets for pharmacological intervention within the drainage system as a target for glaucoma therapy.

Mycobacterium leprae Activates Toll-Like Receptor-4 Signaling and Expression on Macrophages Depending on Previous Bacillus Calmette-Guerin Vaccination.

PubMed

Polycarpou, Anastasia; Holland, Martin J; Karageorgiou, Ioannis; Eddaoudi, Ayad; Walker, Stephen L; Willcocks, Sam; Lockwood, Diana N J

2016-01-01

Toll-like receptor (TLR)-1 and TLR2 have been shown to be receptors for Mycobacterium leprae (M. leprae), yet it is unclear whether M. leprae can signal through alternative TLRs. Other mycobacterial species possess ligands for TLR4 and genetic association studies in human populations suggest that people with TLR4 polymorphisms may be protected against leprosy. Using human embryonic kidney (HEK)-293 cells co-transfected with TLR4, we demonstrate that M. leprae activates TLR4. We used human macrophages to show that M. leprae stimulation of cytokine production is diminished if pre-treated with TLR4 neutralizing antibody. TLR4 protein expression was up-regulated on macrophages derived from non-bacillus Calmette-Guerin (BCG) vaccinated healthy volunteers after incubation with M. leprae, whereas it was down-regulated in macrophages derived from BCG-vaccinated donors. Finally, pre-treatment of macrophages derived from BCG-naive donors with BCG reversed the effect of M. leprae on TLR4 expression. This may be a newly described phenomenon by which BCG vaccination stimulates "non-specific" protection to the human immune system.

Post-translational regulation of WRKY transcription factors in plant immunity.

PubMed

Ishihama, Nobuaki; Yoshioka, Hirofumi

2012-08-01

Plants have evolved immune system to protect themselves against invading pathogens. Recent research has illustrated that signaling networks, after perception of diverse pathogen-derived signals, facilitate transcriptional reprogramming through mitogen-activated protein kinase (MAPK) cascades. WRKY proteins, which comprise a large family of plant transcription factors, are key players in plant immune responses. WRKY transcription factors participate in the control of defense-related genes either as positive or as negative regulators, and essentially are regulated at the transcriptional level. Emerging evidence emphasizes that group I WRKY transcription factors, which contain a conserved motif in the N-terminal region, are also activated by MAPK-dependent phosphorylation, underlining their importance in plant immunity. Copyright © 2012 Elsevier Ltd. All rights reserved.

MicroRNA-31 negatively regulates peripherally derived regulatory T-cell generation by repressing retinoic acid-inducible protein 3

PubMed Central

Zhang, Lingyun; Ke, Fang; Liu, Zhaoyuan; Bai, Jing; Liu, Jinlin; Yan, Sha; Xu, Zhenyao; Lou, Fangzhou; Wang, Hong; Zhu, Huiyuan; Sun, Yang; Cai, Wei; Gao, Yuanyuan; Li, Qun; Yu, Xue-Zhong; Qian, Youcun; Hua, Zichun; Deng, Jiong; Li, Qi-Jing; Wang, Honglin

2015-01-01

Peripherally derived regulatory T (pTreg) cell generation requires T-cell receptor (TCR) signalling and the cytokines TGF-β1 and IL-2. Here we show that TCR signalling induces the microRNA miR-31, which negatively regulates pTreg-cell generation. miR-31 conditional deletion results in enhanced induction of pTreg cells, and decreased severity of experimental autoimmune encephalomyelitis (EAE). Unexpectedly, we identify Gprc5a as a direct target of miR-31. Gprc5a is known as retinoic acid-inducible protein 3, and its deficiency leads to impaired pTreg-cell induction and increased EAE severity. By generating miR-31 and Gprc5a double knockout mice, we show that miR-31 promotes the development of EAE through inhibiting Gprc5a. Thus, our data identify miR-31 and its target Gprc5a as critical regulators for pTreg-cell generation, suggesting a previously unrecognized epigenetic mechanism for dysfunctional Treg cells in autoimmune diseases. PMID:26165721

The Regulatory Role of Signaling Crosstalk in Hypertrophy of MSCs and Human Articular Chondrocytes.

PubMed

Zhong, Leilei; Huang, Xiaobin; Karperien, Marcel; Post, Janine N

2015-08-14

Hypertrophic differentiation of chondrocytes is a main barrier in application of mesenchymal stem cells (MSCs) for cartilage repair. In addition, hypertrophy occurs occasionally in osteoarthritis (OA). Here we provide a comprehensive review on recent literature describing signal pathways in the hypertrophy of MSCs-derived in vitro differentiated chondrocytes and chondrocytes, with an emphasis on the crosstalk between these pathways. Insight into the exact regulation of hypertrophy by the signaling network is necessary for the efficient application of MSCs for articular cartilage repair and for developing novel strategies for curing OA. We focus on articles describing the role of the main signaling pathways in regulating chondrocyte hypertrophy-like changes. Most studies report hypertrophic differentiation in chondrogenesis of MSCs, in both human OA and experimental OA. Chondrocyte hypertrophy is not under the strict control of a single pathway but appears to be regulated by an intricately regulated network of multiple signaling pathways, such as WNT, Bone morphogenetic protein (BMP)/Transforming growth factor-β (TGFβ), Parathyroid hormone-related peptide (PTHrP), Indian hedgehog (IHH), Fibroblast growth factor (FGF), Insulin like growth factor (IGF) and Hypoxia-inducible factor (HIF). This comprehensive review describes how this intricate signaling network influences tissue-engineering applications of MSCs in articular cartilage (AC) repair, and improves understanding of the disease stages and cellular responses within an OA articular joint.

The Regulatory Role of Signaling Crosstalk in Hypertrophy of MSCs and Human Articular Chondrocytes

PubMed Central

Zhong, Leilei; Huang, Xiaobin; Karperien, Marcel; Post, Janine N.

2015-01-01

Hypertrophic differentiation of chondrocytes is a main barrier in application of mesenchymal stem cells (MSCs) for cartilage repair. In addition, hypertrophy occurs occasionally in osteoarthritis (OA). Here we provide a comprehensive review on recent literature describing signal pathways in the hypertrophy of MSCs-derived in vitro differentiated chondrocytes and chondrocytes, with an emphasis on the crosstalk between these pathways. Insight into the exact regulation of hypertrophy by the signaling network is necessary for the efficient application of MSCs for articular cartilage repair and for developing novel strategies for curing OA. We focus on articles describing the role of the main signaling pathways in regulating chondrocyte hypertrophy-like changes. Most studies report hypertrophic differentiation in chondrogenesis of MSCs, in both human OA and experimental OA. Chondrocyte hypertrophy is not under the strict control of a single pathway but appears to be regulated by an intricately regulated network of multiple signaling pathways, such as WNT, Bone morphogenetic protein (BMP)/Transforming growth factor-β (TGFβ), Parathyroid hormone-related peptide (PTHrP), Indian hedgehog (IHH), Fibroblast growth factor (FGF), Insulin like growth factor (IGF) and Hypoxia-inducible factor (HIF). This comprehensive review describes how this intricate signaling network influences tissue-engineering applications of MSCs in articular cartilage (AC) repair, and improves understanding of the disease stages and cellular responses within an OA articular joint. PMID:26287176

The fibroblast-derived paracrine factor neuregulin-1 has a novel role in regulating the constitutive color and melanocyte function in human skin

PubMed Central

Choi, Wonseon; Wolber, Rainer; Gerwat, Wolfram; Mann, Tobias; Batzer, Jan; Smuda, Christoph; Liu, Hongfang; Kolbe, Ludger; Hearing, Vincent J.

2010-01-01

Interactions between melanocytes and neighboring cells in the skin are important in regulating skin color in humans. We recently demonstrated that the less pigmented and thicker skin on the palms and soles is regulated by underlying fibroblasts in those areas, specifically via a secreted factor (DKK1) that modulates Wnt signaling. In this study, we tested the hypothesis that dermal fibroblasts regulate the constitutive skin color of individuals ranging from very light to very dark. We used microarray analysis to compare gene expression patterns in fibroblasts derived from lighter skin types compared to darker skin types, with a focus on secreted proteins. We identified a number of genes that differ dramatically in expression and, among the expressed proteins, neuregulin-1, which is secreted by fibroblasts derived from dark skin, effectively increases the pigmentation of melanocytes in tissue culture and in an artificial skin model and regulates their growth, suggesting that it is one of the major factors determining human skin color. PMID:20736300

Jab1 regulates Schwann cell proliferation and axonal sorting through p27

PubMed Central

Porrello, Emanuela; Rivellini, Cristina; Dina, Giorgia; Triolo, Daniela; Del Carro, Ubaldo; Ungaro, Daniela; Panattoni, Martina; Feltri, Maria Laura; Wrabetz, Lawrence; Pardi, Ruggero; Quattrini, Angelo

2014-01-01

Axonal sorting is a crucial event in nerve formation and requires proper Schwann cell proliferation, differentiation, and contact with axons. Any defect in axonal sorting results in dysmyelinating peripheral neuropathies. Evidence from mouse models shows that axonal sorting is regulated by laminin211– and, possibly, neuregulin 1 (Nrg1)–derived signals. However, how these signals are integrated in Schwann cells is largely unknown. We now report that the nuclear Jun activation domain–binding protein 1 (Jab1) may transduce laminin211 signals to regulate Schwann cell number and differentiation during axonal sorting. Mice with inactivation of Jab1 in Schwann cells develop a dysmyelinating neuropathy with axonal sorting defects. Loss of Jab1 increases p27 levels in Schwann cells, which causes defective cell cycle progression and aberrant differentiation. Genetic down-regulation of p27 levels in Jab1-null mice restores Schwann cell number, differentiation, and axonal sorting and rescues the dysmyelinating neuropathy. Thus, Jab1 constitutes a regulatory molecule that integrates laminin211 signals in Schwann cells to govern cell cycle, cell number, and differentiation. Finally, Jab1 may constitute a key molecule in the pathogenesis of dysmyelinating neuropathies. PMID:24344238

A Signal Peptide Derived from hsp60 Binds HLA-E and Interferes with CD94/NKG2A Recognition

PubMed Central

Michaëlsson, Jakob; Teixeira de Matos, Cristina; Achour, Adnane; Lanier, Lewis L.; Kärre, Klas; Söderström, Kalle

2002-01-01

Human histocompatibility leukocyte antigen (HLA)-E is a nonclassical major histocompatibility complex (MHC) class I molecule which presents a restricted set of nonameric peptides, derived mainly from the signal sequence of other MHC class I molecules. It interacts with CD94/NKG2 receptors expressed on the surface of natural killer (NK) cells and T cell subsets. Here we demonstrate that HLA-E also presents a peptide derived from the leader sequence of human heat shock protein 60 (hsp60). This peptide gains access to HLA-E intracellularly, resulting in up-regulated HLA-E/hsp60 signal peptide cell-surface levels on stressed cells. Notably, HLA-E molecules in complex with the hsp60 signal peptide are no longer recognized by CD94/NKG2A inhibitory receptors. Thus, during cellular stress an increased proportion of HLA-E molecules may bind the nonprotective hsp60 signal peptide, leading to a reduced capacity to inhibit a major NK cell population. Such stress induced peptide interference would gradually uncouple CD94/NKG2A inhibitory recognition and provide a mechanism for NK cells to detect stressed cells in a peptide-dependent manner. PMID:12461076

Microparticles release by adipocytes act as "find-me" signals to promote macrophage migration.

PubMed

Eguchi, Akiko; Mulya, Anny; Lazic, Milos; Radhakrishnan, Deepa; Berk, Michael P; Povero, Davide; Gornicka, Agnieszka; Feldstein, Ariel E

2015-01-01

Macrophage infiltration of adipose tissue during weight gain is a central event leading to the metabolic complications of obesity. However, what are the mechanisms attracting professional phagocytes to obese adipose tissue remains poorly understood. Here, we demonstrate that adipocyte-derived microparticles (MPs) are critical "find-me" signals for recruitment of monocytes and macrophages. Supernatants from stressed adipocytes stimulated the attraction of monocyte cells and primary macrophages. The activation of caspase 3 was required for release of these signals. Adipocytes exposed to saturated fatty acids showed marked release of MPs into the supernatant while common genetic mouse models of obesity demonstrate high levels of circulating adipocyte-derived MPs. The release of MPs was highly regulated and dependent on caspase 3 and Rho-associated kinase. Further analysis identified these MPs as a central chemoattractant in vitro and in vivo. In addition, intravenously transplanting circulating MPs from the ob/ob mice lead to activation of monocytes in circulation and adipose tissue of the wild type mice. These data identify adipocyte-derived MPs as novel "find me" signals that contributes to macrophage infiltration associated with obesity.

A Tightly Regulated Genetic Selection System with Signaling-Active Alleles of Phytochrome B.

PubMed

Hu, Wei; Lagarias, J Clark

2017-01-01

Selectable markers derived from plant genes circumvent the potential risk of antibiotic/herbicide-resistance gene transfer into neighboring plant species, endophytic bacteria, and mycorrhizal fungi. Toward this goal, we have engineered and validated signaling-active alleles of phytochrome B (eYHB) as plant-derived selection marker genes in the model plant Arabidopsis (Arabidopsis thaliana). By probing the relationship of construct size and induction conditions to optimal phenotypic selection, we show that eYHB-based alleles are robust substitutes for antibiotic/herbicide-dependent marker genes as well as surprisingly sensitive reporters of off-target transgene expression. © 2017 American Society of Plant Biologists. All Rights Reserved.

A Tightly Regulated Genetic Selection System with Signaling-Active Alleles of Phytochrome B1[OPEN

PubMed Central

2017-01-01

Selectable markers derived from plant genes circumvent the potential risk of antibiotic/herbicide-resistance gene transfer into neighboring plant species, endophytic bacteria, and mycorrhizal fungi. Toward this goal, we have engineered and validated signaling-active alleles of phytochrome B (eYHB) as plant-derived selection marker genes in the model plant Arabidopsis (Arabidopsis thaliana). By probing the relationship of construct size and induction conditions to optimal phenotypic selection, we show that eYHB-based alleles are robust substitutes for antibiotic/herbicide-dependent marker genes as well as surprisingly sensitive reporters of off-target transgene expression. PMID:27881727

Caffeic acid phenethyl ester suppresses monocyte adhesion to the endothelium by inhibiting NF-κB/NOX2-derived ROS signaling

PubMed Central

Nakahara, Risa; Makino, Junya; Kamiya, Tetsuro; Hara, Hirokazu; Adachi, Tetsuo

2016-01-01

Caffeic acid phenethyl ester (CAPE), one of the major polyphenols, exhibits anti-oxidative, anti-bacterial, and anti-cancer properties. Atherosclerosis is a chronic inflammatory disease, the progression of which is closely related to the accumulated adhesion of inflammatory monocytes/macrophages to the endothelium. We herein determined whether CAPE and its derivatives suppressed THP-1 cell adhesion to human umbilical vein endothelial cells (HUVEC). Of the four polyphenols tested, CAPE significantly suppressed the 12-O-tetradecanoylphorbol 13-acetate (TPA)-elicited expression of cluster for differentiation (CD) 11b, 14, and 36, and this was accompanied by the inhibition of THP-1 cell adhesion to HUVEC. CAPE also suppressed the activation of TPA-elicited nuclear factor-κB (NF-κB) and accumulation of NADPH oxidase 2 (NOX2)-derived reactive oxygen species (ROS), but did not affect extracellular signal-regulated kinase (ERK) phosphorylation. Taken together, these results demonstrated that CAPE suppressed THP-1 cell adhesion to HUVEC through, at least in part, the NF-κB, NOX2, and ROS-derived signaling axis. PMID:27257341

Leptin signaling protects the gut from Entamoeba histolytica infection.

PubMed

Vedantam, Gayatri; Viswanathan, V K

2012-01-01

The role of the adipose-derived hormone leptin, and leptin receptors, in signaling satiety to the central nervous system and regulating energy balance is well recognized. But leptin also acts on peripheral tissues such as skeletal muscles, adipose tissues, pancreas, liver, intestine and the immune system. The existence of different splice variants of leptin receptor and the numerous intracellular signaling pathways triggered by leptin make this a truly versatile system. Two recent studies explore the link between malnutrition, leptin signaling and susceptibility to amebic infection. These studies point to important and novel aspects of leptin signaling in maintaining gut homeostasis and warding off infections.

Up-regulation of CXCR4 expression contributes to persistent abdominal pain in rats with chronic pancreatitis.

PubMed

Zhu, Hong-Yan; Liu, Xuelian; Miao, Xiuhua; Li, Di; Wang, Shusheng; Xu, Guang-Yin

2017-01-01

Background Pain in patients with chronic pancreatitis is critical hallmark that accompanied inflammation, fibrosis, and destruction of glandular pancreas. Many researchers have demonstrated that stromal cell-derived factor 1 (also named as CXCL12) and its cognate receptor C-X-C chemokine receptor type 4 (CXCR4) involved in mediating neuropathic and bone cancer pain. However, their roles in chronic pancreatic pain remain largely unclear. Methods Chronic pancreatitis was induced by intraductal injection of trinitrobenzene sulfonic acid to the pancreas. Von Frey filament tests were conducted to evaluate pancreas hypersensitivity of rat. Expression of CXCL12, CXCR4, NaV1.8, and pERK in rat dorsal root ganglion was detected by Western blot analyses. Dorsal root ganglion neuronal excitability was assessed by electrophysiological recordings. Results We showed that both CXCL12 and CXCR4 were dramatically up-regulated in the dorsal root ganglion in trinitrobenzene sulfonic acid-induced chronic pancreatitis pain model. Intrathecal application with AMD3100, a potent and selective CXCR4 inhibitor, reversed the hyperexcitability of dorsal root ganglion neurons innervating the pancreas of rats following trinitrobenzene sulfonic acid injection. Furthermore, trinitrobenzene sulfonic acid-induced extracellular signal-regulated kinase activation and Nav1.8 up-regulation in dorsal root ganglias were reversed by intrathecal application with AMD3100 as well as by blockade of extracellular signal-regulated kinase activation by intrathecal U0126. More importantly, the trinitrobenzene sulfonic acid-induced persistent pain was significantly suppressed by CXCR4 and extracellular signal-regulated kinase inhibitors. Conclusions The present results suggest that the activation of CXCL12-CXCR4 signaling might contribute to pancreatic pain and that extracellular signal-regulated kinase-dependent Nav1.8 up-regulation might lead to hyperexcitability of the primary nociceptor neurons in rats with chronic pancreatitis.

Neurotrophin signaling and visceral hypersensitivity.

PubMed

Qiao, Li-Ya

2014-06-01

Neurotrophin family are traditionally recognized for their nerve growth promoting function and are recently identified as crucial factors in regulating neuronal activity in the central and peripheral nervous systems. The family members including nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF), and neurotrophin-3 (NT-3) are reported to have distinct roles in the development and maintenance of sensory phenotypes in normal states and in the modulation of sensory activity in disease. This paper highlights receptor tyrosine kinase (Trk) -mediated signal transduction by which neurotrophins regulate neuronal activity in the visceral sensory reflex pathways with emphasis on the distinct roles of NGF and BDNF signaling in physiologic and pathophysiological processes. Viscero-visceral cross-organ sensitization exists widely in human diseases. The role of neurotrophins in mediating neural cross talk and interaction in primary afferent neurons in the dorsal root ganglia (DRG) and neurotrophin signal transduction in the context of cross-organ sensitization are also discussed.

iPSC-derived cardiomyocytes reveal abnormal TGFβ signaling in left ventricular non-compaction cardiomyopathy

PubMed Central

Kodo, Kazuki; Ong, Sang-Ging; Jahanbani, Fereshteh; Termglinchan, Vittavat; Hirono, Keiichi; InanlooRahatloo, Kolsoum; Ebert, Antje D.; Shukla, Praveen; Abilez, Oscar J.; Churko, Jared M.; Karakikes, Ioannis; Jung, Gwanghyun; Ichida, Fukiko; Wu, Sean M.; Snyder, Michael P.; Bernstein, Daniel; Wu, Joseph C.

2016-01-01

Left ventricular non-compaction (LVNC) is the third most prevalent cardiomyopathy in children and its pathogenesis has been associated with the developmental defect of the embryonic myocardium. We show that patient-specific induced pluripotent stem cell-derived cardiomyocytes (iPSC-CMs) generated from LVNC patients carrying a mutation in the cardiac transcription factor TBX20 recapitulate a key aspect of the pathological phenotype at the single-cell level and was associated with perturbed transforming growth factor beta (TGFβ) signaling. LVNC iPSC-CMs have decreased proliferative capacity due to abnormal activation of TGFβ signaling. TBX20 regulates the expression of TGFβ signaling modifiers including a known genetic cause of LVNC, PRDM16, and genome editing of PRDM16 caused proliferation defects in iPSC-CMs. Inhibition of TGFβ signaling and genome correction of the TBX20 mutation were sufficient to reverse the disease phenotype. Our study demonstrates that iPSC-CMs are a useful tool for the exploration of pathological mechanisms underlying poorly understood cardiomyopathies including LVNC. PMID:27642787

ADP-ribosyl cyclases regulate early development of the sea urchin.

PubMed

Ramakrishnan, Latha; Uhlinger, Kevin; Dale, Leslie; Hamdoun, Amro; Patel, Sandip

2016-06-01

ADP-ribosyl cyclases are multifunctional enzymes involved in the metabolism of nucleotide derivatives necessary for Ca 2+ signalling such as cADPR and NAADP. Although Ca 2+ signalling is a critical regulator of early development, little is known of the role of ADP-ribosyl cyclases during embryogenesis. Here we analyze the expression, activity and function of ADP-ribosyl cyclases in the embryo of the sea urchin - a key organism for study of both Ca 2+ signalling and embryonic development. ADP-ribosyl cyclase isoforms (SpARC1-4) showed unique changes in expression during early development. These changes were associated with an increase in the ratio of cADPR:NAADP production. Over-expression of SpARC4 (a preferential cyclase) disrupted gastrulation. Our data highlight the importance of ADP-ribosyl cyclases during embryogenesis.

Collybistin binds and inhibits mTORC1 signaling: a potential novel mechanism contributing to intellectual disability and autism.

PubMed

Machado, Camila Oliveira Freitas; Griesi-Oliveira, Karina; Rosenberg, Carla; Kok, Fernando; Martins, Stephanie; Passos-Bueno, Maria Rita; Sertie, Andrea Laurato

2016-01-01

Protein synthesis regulation via mammalian target of rapamycin complex 1 (mTORC1) signaling pathway has key roles in neural development and function, and its dysregulation is involved in neurodevelopmental disorders associated with autism and intellectual disability. mTOR regulates assembly of the translation initiation machinery by interacting with the eukaryotic initiation factor eIF3 complex and by controlling phosphorylation of key translational regulators. Collybistin (CB), a neuron-specific Rho-GEF responsible for X-linked intellectual disability with epilepsy, also interacts with eIF3, and its binding partner gephyrin associates with mTOR. Therefore, we hypothesized that CB also binds mTOR and affects mTORC1 signaling activity in neuronal cells. Here, by using induced pluripotent stem cell-derived neural progenitor cells from a male patient with a deletion of entire CB gene and from control individuals, as well as a heterologous expression system, we describe that CB physically interacts with mTOR and inhibits mTORC1 signaling pathway and protein synthesis. These findings suggest that disinhibited mTORC1 signaling may also contribute to the pathological process in patients with loss-of-function variants in CB.

Distinct requirements for TrkB and TrkC signaling in target innervation by sensory neurons

NASA Technical Reports Server (NTRS)

Postigo, Antonio; Calella, Anna Maria; Fritzsch, Bernd; Knipper, Marlies; Katz, David; Eilers, Andreas; Schimmang, Thomas; Lewin, Gary R.; Klein, Rudiger; Minichiello, Liliana

2002-01-01

Signaling by brain-derived neurotrophic factor (BDNF) via the TrkB receptor, or by neurotrophin-3 (NT3) through the TrkC receptor support distinct populations of sensory neurons. The intracellular signaling pathways activated by Trk (tyrosine kinase) receptors, which in vivo promote neuronal survival and target innervation, are not well understood. Using mice with TrkB or TrkC receptors lacking the docking site for Shc adaptors (trkB(shc/shc) and trkC(shc/shc) mice), we show that TrkB and TrkC promote survival of sensory neurons mainly through Shc site-independent pathways, suggesting that these receptors use similar pathways to prevent apoptosis. In contrast, the regulation of target innervation appears different: in trkB(shc/shc) mice neurons lose target innervation, whereas in trkC(shc/shc) mice the surviving TrkC-dependent neurons maintain target innervation and function. Biochemical analysis indicates that phosphorylation at the Shc site positively regulates autophosphorylation of TrkB, but not of TrkC. Our findings show that although TrkB and TrkC signals mediating survival are largely similar, TrkB and TrkC signals required for maintenance of target innervation in vivo are regulated by distinct mechanisms.

Collybistin binds and inhibits mTORC1 signaling: a potential novel mechanism contributing to intellectual disability and autism

PubMed Central

Machado, Camila Oliveira Freitas; Griesi-Oliveira, Karina; Rosenberg, Carla; Kok, Fernando; Martins, Stephanie; Rita Passos-Bueno, Maria; Sertie, Andrea Laurato

2016-01-01

Protein synthesis regulation via mammalian target of rapamycin complex 1 (mTORC1) signaling pathway has key roles in neural development and function, and its dysregulation is involved in neurodevelopmental disorders associated with autism and intellectual disability. mTOR regulates assembly of the translation initiation machinery by interacting with the eukaryotic initiation factor eIF3 complex and by controlling phosphorylation of key translational regulators. Collybistin (CB), a neuron-specific Rho-GEF responsible for X-linked intellectual disability with epilepsy, also interacts with eIF3, and its binding partner gephyrin associates with mTOR. Therefore, we hypothesized that CB also binds mTOR and affects mTORC1 signaling activity in neuronal cells. Here, by using induced pluripotent stem cell-derived neural progenitor cells from a male patient with a deletion of entire CB gene and from control individuals, as well as a heterologous expression system, we describe that CB physically interacts with mTOR and inhibits mTORC1 signaling pathway and protein synthesis. These findings suggest that disinhibited mTORC1 signaling may also contribute to the pathological process in patients with loss-of-function variants in CB. PMID:25898924

Regulation of T cell homeostasis by JAKs and STATs.

PubMed

Ross, Jeremy A; Nagy, Zsuzsanna S; Cheng, Hanyin; Stepkowski, Stanislaw M; Kirken, Robert A

2007-01-01

Regulation of T cell homeostasis is critical for maintaining normal immune function. An imbalance in T cell proliferation can result in disorders ranging from cancer and autoimmunity to immunodeficiencies. Full activation of T cells requires three sequential signals, where signal 3, which is delivered by multiple cytokines, regulates proliferation, differentiation, and survival/death. Signaling from cytokines through their receptors is primarily delivered by two molecular families, namely Janus tyrosine kinases (JAKs) and signal transducers and activators of transcription (STATs). Invaluable knowledge about JAKs and STATs has arisen from studies of mice made genetically deficient in these molecules, analyses of tumor models, and studies of expression patterns by proteomics/genomics, which all have begun to define the role of JAKs and STATs in survival versus apoptosis. These findings also have suggested ways in which JAKs and STATs may be manipulated for therapeutic intervention in lymphoid-derived diseases. This review seeks to focus on the role of JAK tyrosine kinases and STAT transcription factors in mediating the lymphocyte life cycle and how they might be manipulated for therapeutic applications.

Glycolaldehyde-derived advanced glycation end products (glycol-AGEs)-induced vascular smooth muscle cell dysfunction is regulated by the AGES-receptor (RAGE) axis in endothelium.

PubMed

Nam, Mi-Hyun; Son, Won-Rak; Lee, Young Sik; Lee, Kwang-Won

Advanced glycation end-products (AGEs) are involved in the development of vascular smooth muscle cell (VSMC) dysfunction and the progression of atherosclerosis. However, AGEs may indirectly affect VSMCs via AGEs-induced signal transduction between monocytes and human umbilical endothelial cells (HUVECs), rather than having a direct influence. This study was designed to elucidate the signaling pathway underlying AGEs-RAGE axis influence on VSMC dysfunction using a co-culture system with monocytes, HUVECs and VSMCs. AGEs stimulated production of reactive oxygen species and pro-inflammatory mediators such as tumor necrosis factor-α and interleukin-1β via extracellular-signal-regulated kinases phosphorylation and nuclear factor-κB activation in HUVECs. It was observed that AGEs-induced pro-inflammatory cytokines increase VSMC proliferation, inflammation and vascular remodeling in the co-culture system. This result implies that RAGE plays a role in AGEs-induced VSMC dysfunction. We suggest that the regulation of signal transduction via the AGEs-RAGE axis in the endothelium can be a therapeutic target for preventing atherosclerosis.

Commensal bacterial–derived signals regulate basophil hematopoiesis and allergic inflammation

PubMed Central

Hill, David A.; Siracusa, Mark C.; Abt, Michael C.; Kim, Brian S.; Kobuley, Dmytro; Kubo, Masato; Kambayashi, Taku; LaRosa, David F.; Renner, Ellen D.; Orange, Jordan S.; Bushman, Frederic D.; Artis, David

2012-01-01

Commensal bacteria that colonize mammalian barrier surfaces are reported to influence T helper type 2 (TH2) cytokine–dependent inflammation and susceptibility to allergic disease, although the mechanisms that underlie these observations are poorly understood. In this report, we identify that deliberate alteration of commensal bacterial populations via oral antibiotic treatment resulted in elevated serum immunoglobulin E (IgE) levels, increased steady–state circulating basophil populations, and exaggerated basophil–mediated TH2 cell responses and allergic inflammation. Elevated serum IgE levels correlated with increased circulating basophil populations in mice and subjects with hyperimmunoglobulinemia E syndrome. Furthermore, B cell–intrinsic expression of MyD88 was required to limit serum IgE levels and circulating basophil populations in mice. Commensal–derived signals were found to influence basophil development by limiting proliferation of bone marrow–resident precursor populations. Collectively, these results identify a previously unrecognized pathway through which commensal–derived signals influence basophil hematopoiesis and susceptibility to TH2 cytokine–dependent inflammation and allergic disease. PMID:22447074

Canonical TGF-β Signaling Negatively Regulates Neuronal Morphogenesis through TGIF/Smad Complex-Mediated CRMP2 Suppression.

PubMed

Nakashima, Hideyuki; Tsujimura, Keita; Irie, Koichiro; Ishizu, Masataka; Pan, Miao; Kameda, Tomonori; Nakashima, Kinichi

2018-05-16

Functional neuronal connectivity requires proper neuronal morphogenesis and its dysregulation causes neurodevelopmental diseases. Transforming growth factor-β (TGF-β) family cytokines play pivotal roles in development, but little is known about their contribution to morphological development of neurons. Here we show that the Smad-dependent canonical signaling of TGF-β family cytokines negatively regulates neuronal morphogenesis during brain development. Mechanistically, activated Smads form a complex with transcriptional repressor TG-interacting factor (TGIF), and downregulate the expression of a neuronal polarity regulator, collapsin response mediator protein 2. We also demonstrate that TGF-β family signaling inhibits neurite elongation of human induced pluripotent stem cell-derived neurons. Furthermore, the expression of TGF-β receptor 1, Smad4, or TGIF, which have mutations found in patients with neurodevelopmental disorders, disrupted neuronal morphogenesis in both mouse (male and female) and human (female) neurons. Together, these findings suggest that the regulation of neuronal morphogenesis by an evolutionarily conserved function of TGF-β signaling is involved in the pathogenesis of neurodevelopmental diseases. SIGNIFICANCE STATEMENT Canonical transforming growth factor-β (TGF-β) signaling plays a crucial role in multiple organ development, including brain, and mutations in components of the signaling pathway associated with several human developmental disorders. In this study, we found that Smads/TG-interacting factor-dependent canonical TGF-β signaling regulates neuronal morphogenesis through the suppression of collapsin response mediator protein-2 (CRMP2) expression during brain development, and that function of this signaling is evolutionarily conserved in the mammalian brain. Mutations in canonical TGF-β signaling factors identified in patients with neurodevelopmental disorders disrupt the morphological development of neurons. Thus, our results suggest that proper control of TGF-β/Smads/CRMP2 signaling pathways is critical for the precise execution of neuronal morphogenesis, whose impairment eventually results in neurodevelopmental disorders. Copyright © 2018 the authors 0270-6474/18/384791-20$15.00/0.

BIOCONCENTRATION AND METABOLISM OF ALL-TRANS RETINOIC ACID BY RANA SYLVATICA AND RANA CLAMITANS TADPOLES

EPA Science Inventory

Retinoids, which are Vitamin A derivatives, are important signaling molecules that regulate processes critical for development in all vertebrates. The objective of our study was to examine uptake and metabolism of all-trans retinoic acid...

miR-96 promotes osteogenic differentiation by suppressing HBEGF-EGFR signaling in osteoblastic cells.

PubMed

Yang, Mingfu; Pan, Yong; Zhou, Yue

2014-12-20

MicroRNAs (miRNAs) are a class of small non-coding RNAs with important roles in various biological and pathological processes, including osteoblast differentiation. Here, we identified miR-96 as a positive regulator of osteogenic differentiation in a mouse osteoblastic cell line (MC3T3-E1) and in mouse bone marrow-derived mesenchymal stem cells. Moreover, we found that miR-96 down-regulates post-transcriptional expression of heparin-binding EGF-like growth factor (HB-EGF) by specifically binding to the 3'untranslated region of HB-EGF mRNA. Furthermore, in MC3T3-E1 cells, miR-96-induced HB-EGF down-regulation suppressed the phosphorylation of epidermal growth factor receptor (EGFR) and of extracellular signal-regulated kinase 1 (ERK1) and AKT, which both lie downstream of EGFR activation. Taken together, miR-96 promotes osteogenic differentiation by inhibiting HB-EGF and by blocking the HB-EGF-EGFR signaling pathway in osteoblastic cells. Copyright © 2014 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.

The tumor marker Fascin is strongly induced by the Tax oncoprotein of HTLV-1 through NF-kappaB signals.

PubMed

Kress, Andrea K; Kalmer, Martina; Rowan, Aileen G; Grassmann, Ralph; Fleckenstein, Bernhard

2011-03-31

Oncogenic transformation of CD4(+) T cells by human T-cell lymphotropic virus type 1 (HTLV-1) is understood as the initial step to adult T-cell leukemia/lymphoma, a process that is mainly initiated by perturbation of cellular signaling by the viral Tax oncoprotein, a potent transcriptional regulator. In search of novel biomarkers with relevance to oncogenesis, we identified the tumor marker and actin-bundling protein Fascin (FSCN1) to be specifically and strongly up-regulated in both HTLV-1-transformed and adult T-cell leukemia/lymphoma patient-derived CD4(+) T cells. Fascin is important for migration and metastasis in various types of cancer. Here we report that a direct link can exist between a single viral oncoprotein and Fascin expression, as the viral oncoprotein Tax was sufficient to induce high levels of Fascin. Nuclear factor-κB signals were important for Tax-mediated transcriptional regulation of Fascin in T cells. This suggests that Fascin up-regulation by Tax contributes to the development of HTLV-1-associated pathogenesis.

Exosome Adherence and Internalization by Hepatic Stellate Cells Triggers Sphingosine 1-Phosphate-dependent Migration*

PubMed Central

Wang, Ruisi; Ding, Qian; Yaqoob, Usman; de Assuncao, Thiago M.; Verma, Vikas K.; Hirsova, Petra; Cao, Sheng; Mukhopadhyay, Debabrata; Huebert, Robert C.; Shah, Vijay H.

2015-01-01

Exosomes are cell-derived extracellular vesicles thought to promote intercellular communication by delivering specific content to target cells. The aim of this study was to determine whether endothelial cell (EC)-derived exosomes could regulate the phenotype of hepatic stellate cells (HSCs). Initial microarray studies showed that fibroblast growth factor 2 induced a 2.4-fold increase in mRNA levels of sphingosine kinase 1 (SK1). Exosomes derived from an SK1-overexpressing EC line increased HSC migration 3.2-fold. Migration was not conferred by the dominant negative SK1 exosome. Incubation of HSCs with exosomes was also associated with an 8.3-fold increase in phosphorylation of AKT and 2.5-fold increase in migration. Exosomes were found to express the matrix protein and integrin ligand fibronectin (FN) by Western blot analysis and transmission electron microscopy. Blockade of the FN-integrin interaction with a CD29 neutralizing antibody or the RGD peptide attenuated exosome-induced HSC AKT phosphorylation and migration. Inhibition of endocytosis with transfection of dynamin siRNA, the dominant negative dynamin GTPase construct Dyn2K44A, or the pharmacological inhibitor Dynasore significantly attenuated exosome-induced AKT phosphorylation. SK1 levels were increased in serum exosomes derived from mice with experimental liver fibrosis, and SK1 mRNA levels were up-regulated 2.5-fold in human liver cirrhosis patient samples. Finally, S1PR2 inhibition protected mice from CCl4-induced liver fibrosis. Therefore, EC-derived SK1-containing exosomes regulate HSC signaling and migration through FN-integrin-dependent exosome adherence and dynamin-dependent exosome internalization. These findings advance our understanding of EC/HSC cross-talk and identify exosomes as a potential target to attenuate pathobiology signals. PMID:26534962

Exosome Adherence and Internalization by Hepatic Stellate Cells Triggers Sphingosine 1-Phosphate-dependent Migration.

PubMed

Wang, Ruisi; Ding, Qian; Yaqoob, Usman; de Assuncao, Thiago M; Verma, Vikas K; Hirsova, Petra; Cao, Sheng; Mukhopadhyay, Debabrata; Huebert, Robert C; Shah, Vijay H

2015-12-25

Exosomes are cell-derived extracellular vesicles thought to promote intercellular communication by delivering specific content to target cells. The aim of this study was to determine whether endothelial cell (EC)-derived exosomes could regulate the phenotype of hepatic stellate cells (HSCs). Initial microarray studies showed that fibroblast growth factor 2 induced a 2.4-fold increase in mRNA levels of sphingosine kinase 1 (SK1). Exosomes derived from an SK1-overexpressing EC line increased HSC migration 3.2-fold. Migration was not conferred by the dominant negative SK1 exosome. Incubation of HSCs with exosomes was also associated with an 8.3-fold increase in phosphorylation of AKT and 2.5-fold increase in migration. Exosomes were found to express the matrix protein and integrin ligand fibronectin (FN) by Western blot analysis and transmission electron microscopy. Blockade of the FN-integrin interaction with a CD29 neutralizing antibody or the RGD peptide attenuated exosome-induced HSC AKT phosphorylation and migration. Inhibition of endocytosis with transfection of dynamin siRNA, the dominant negative dynamin GTPase construct Dyn2K44A, or the pharmacological inhibitor Dynasore significantly attenuated exosome-induced AKT phosphorylation. SK1 levels were increased in serum exosomes derived from mice with experimental liver fibrosis, and SK1 mRNA levels were up-regulated 2.5-fold in human liver cirrhosis patient samples. Finally, S1PR2 inhibition protected mice from CCl4-induced liver fibrosis. Therefore, EC-derived SK1-containing exosomes regulate HSC signaling and migration through FN-integrin-dependent exosome adherence and dynamin-dependent exosome internalization. These findings advance our understanding of EC/HSC cross-talk and identify exosomes as a potential target to attenuate pathobiology signals. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

Possible Signaling Pathways Mediating Neuronal Calcium Sensor-1-Dependent Spatial Learning and Memory in Mice.

PubMed

Nakamura, Tomoe Y; Nakao, Shu; Nakajo, Yukako; Takahashi, Jun C; Wakabayashi, Shigeo; Yanamoto, Hiroji

2017-01-01

Intracellular Ca2+ signaling regulates diverse functions of the nervous system. Many of these neuronal functions, including learning and memory, are regulated by neuronal calcium sensor-1 (NCS-1). However, the pathways by which NCS-1 regulates these functions remain poorly understood. Consistent with the findings of previous reports, we revealed that NCS-1 deficient (Ncs1-/-) mice exhibit impaired spatial learning and memory function in the Morris water maze test, although there was little change in their exercise activity, as determined via treadmill-analysis. Expression of brain-derived neurotrophic factor (BDNF; a key regulator of memory function) and dopamine was significantly reduced in the Ncs1-/- mouse brain, without changes in the levels of glial cell-line derived neurotrophic factor or nerve growth factor. Although there were no gross structural abnormalities in the hippocampi of Ncs1-/- mice, electron microscopy analysis revealed that the density of large dense core vesicles in CA1 presynaptic neurons, which release BDNF and dopamine, was decreased. Phosphorylation of Ca2+/calmodulin-dependent protein kinase II-α (CaMKII-α, which is known to trigger long-term potentiation and increase BDNF levels, was significantly reduced in the Ncs1-/- mouse brain. Furthermore, high voltage electric potential stimulation, which increases the levels of BDNF and promotes spatial learning, significantly increased the levels of NCS-1 concomitant with phosphorylated CaMKII-α in the hippocampus; suggesting a close relationship between NCS-1 and CaMKII-α. Our findings indicate that NCS-1 may regulate spatial learning and memory function at least in part through activation of CaMKII-α signaling, which may directly or indirectly increase BDNF production.

Could there be a fine-tuning role for brain-derived adipokines in the regulation of bodyweight and prevention of obesity?

PubMed Central

Brown, Russell E.

2008-01-01

Obesity is one of the most prevalent medical conditions, often associated with several negative stereotypes. Although it is true that weight gain occurs when food intake exceeds energy expenditure, it is important to note that even a 1% mismatch between the two can lead to a substantial weight gain after only a few years. Further, the body appears to balance energy metabolism via an endogenous lipostatic loop in which adipose stores send hormonal signals (e.g. adipokines such as leptin) to the hypothalamus in order to reduce appetite and increase energy expenditure. However, the brain is also a novel site of expression of many of these adipokine genes. This led to the hypothesis that hypothalamic-derived adipokines might also be involved in bodyweight regulation by exerting some effect on the control of appetite or hypothalamic function. When RNA interference (RNAi) was used to specifically silence adipokine gene expression in various in vitro models, this led to increases in cell death, modification of the expression of key signaling genes (i.e. suppressor of cytokine signaling-3; SOCS-3), and modulation of the activation of cellular energy sensors (i.e. adenosine monophosphate-activated protein kinase; AMPK). Subsequently, when RNAi was used to inhibit the expression of brain-derived leptin in adult rats this resulted in minor increases in weight gain in addition to modifying the expression of other adipokine genes (eg. resistin). In summary, although adipokines secreted by adipose tissue appear to the main regulator of lipostatic loop, this review shows that the fine tuning that is required to maintain a stable bodyweight by this system might be accomplished by hypothalamic-derived adipokines. Perturbations in this central adipokine system could lead to alterations in normal hypothalamic function which leads to unintended weight gain. PMID:19148319

Immunomodulatory Activities of the Benzoxathiole Derivative BOT-4-One Ameliorate Pathogenic Skin Inflammation in Mice.

PubMed

Lee, Hyun Gyu; Cho, Nam-Chul; Jeong, Ae Jin; Li, Yu-Chen; Rhie, Sung-Ja; Choi, Jung Sook; Lee, Kwang-Ho; Kim, Youngsoo; Kim, Yong-Nyun; Kim, Myoung-Hwan; Pae, Ae Nim; Ye, Sang-Kyu; Kim, Byung-Hak

2016-01-01

T-cell-mediated immune responses play an important role in body protection. However, aberrantly activated immune responses are responsible for inflammatory and autoimmune diseases. The regulation of pathologic immune responses may be a potential therapeutic strategy for the treatment of these diseases. Despite that multiple pharmacologic properties of benzoxathiole derivatives have been defined, the molecular mechanisms underlying these properties remain to be clarified. Here, we demonstrated the benzoxathiole derivative 2-cyclohexylimino-6-methyl-6,7-dihydro-5H-benzo[1,3]oxathiol-4-one (BOT-4-one) regulated immune responses and ameliorated experimentally induced inflammatory skin diseases both in vitro and in vivo. BOT-4-one inhibited the differentiation of CD4(+) T-cell subsets by regulating the expression and production of T-cell lineage-specific master transcription factors and cytokines and activating the signal transducer and activator of transcription proteins. In addition, BOT-4-one inhibited TCR-mediated Akt and NF-κB signaling. Topical application of BOT-4-one ameliorated experimentally induced inflammatory skin diseases in mice models such as 2,4,6-trinitrochlorobenzene-induced contact and atopic dermatitis and IL-23-induced psoriasis-like skin inflammation. Our study demonstrated that BOT-4-one ameliorates inflammatory skin diseases by suppressing the pathogenic CD4(+) T cell differentiation and overall immune responses. Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.

Development and Function of the Drosophila Tracheal System.

PubMed

Hayashi, Shigeo; Kondo, Takefumi

2018-06-01

The tracheal system of insects is a network of epithelial tubules that functions as a respiratory organ to supply oxygen to various target organs. Target-derived signaling inputs regulate stereotyped modes of cell specification, branching morphogenesis, and collective cell migration in the embryonic stage. In the postembryonic stages, the same set of signaling pathways controls highly plastic regulation of size increase and pattern elaboration during larval stages, and cell proliferation and reprograming during metamorphosis. Tracheal tube morphogenesis is also regulated by physicochemical interaction of the cell and apical extracellular matrix to regulate optimal geometry suitable for air flow. The trachea system senses both the external oxygen level and the metabolic activity of internal organs, and helps organismal adaptation to changes in environmental oxygen level. Cellular and molecular mechanisms underlying the high plasticity of tracheal development and physiology uncovered through research on Drosophila are discussed. Copyright © 2018 by the Genetics Society of America.

Biophysical regulation of stem cell differentiation.

PubMed

Govey, Peter M; Loiselle, Alayna E; Donahue, Henry J

2013-06-01

Bone adaptation to its mechanical environment, from embryonic through adult life, is thought to be the product of increased osteoblastic differentiation from mesenchymal stem cells. In parallel with tissue-scale loading, these heterogeneous populations of multipotent stem cells are subject to a variety of biophysical cues within their native microenvironments. Bone marrow-derived mesenchymal stem cells-the most broadly studied source of osteoblastic progenitors-undergo osteoblastic differentiation in vitro in response to biophysical signals, including hydrostatic pressure, fluid flow and accompanying shear stress, substrate strain and stiffness, substrate topography, and electromagnetic fields. Furthermore, stem cells may be subject to indirect regulation by mechano-sensing osteocytes positioned to more readily detect these same loading-induced signals within the bone matrix. Such paracrine and juxtacrine regulation of differentiation by osteocytes occurs in vitro. Further studies are needed to confirm both direct and indirect mechanisms of biophysical regulation within the in vivo stem cell niche.

The Induction of Serine/Threonine Protein Phosphorylations by a PDGFR/TrkA Chimera in Stably Transfected PC12 Cells*

PubMed Central

Biarc, Jordane; Chalkley, Robert J.; Burlingame, A. L.; Bradshaw, Ralph A.

2012-01-01

Stably transfected PC12 cells expressing a chimeric receptor composed of the extracellular domain of the platelet-derived growth factor receptor BB and the transmembrane and intracellular domains of TrkA, the nerve growth factor receptor, were stimulated for 20 min with platelet-derived growth factor and the resulting phosphoproteome was determined from affinity purified tryptic peptides identified by tandem MS (MS/MS) analyses. The changes in the levels of individual phosphorylation sites in stimulated cells versus control were ascertained by the stable isotope labeling of amino acids in cell culture technique. A total of 2035 peptides (806 proteins) were indentified and quantified in both data sets. Of these, 424 phosphopeptides on 259 proteins were found to be up-regulated and 392 sites on 206 proteins were down-regulated (1.8-fold or more). Protein kinases and phosphatases, as well as sites in many proteins involved in G-protein signaling, were prominently represented in the up-regulated group and more than half of the kinase up-regulated phosphosites could be clustered into three sequence motifs; a similar distribution was also found for the down-regulated sites. A comparison of the up-regulated motif profile observed to that calculated from a previous study of the EGFR-induced phosphoproteome in human HeLa cells at the same time point showed a considerable amount of similarity, supporting the view that RTK signal transduction pathways and downstream modifications are likely to be extensively overlapping. PMID:22027198

Z-Guggulsterone Produces Antidepressant-Like Effects in Mice through Activation of the BDNF Signaling Pathway

PubMed Central

Liu, Feng-Guo; Hu, Wen-Feng; Wang, Ji-Li; Wang, Peng; Gong, Yu; Tong, Li-Juan; Jiang, Bo; Zhang, Wei; Qin, Yi-Bin; Chen, Zhuo

2017-01-01

Abstract Background: Z-guggulsterone, an active compound extracted from the gum resin of the tree Commiphora mukul, has been shown to improve animal memory deficits via activating the brain-derived neurotrophic factor signaling pathway. Here, we investigated the antidepressant-like effect of Z-guggulsterone in a chronic unpredictable stress mouse model of depression. Methods: The effects of Z-guggulsterone were assessed in mice with the tail suspension test and forced swimming test. Z-guggulsterone was also investigated in the chronic unpredictable stress model of depression with fluoxetine as the positive control. Changes in hippocampal neurogenesis as well as the brain-derived neurotrophic factor signaling pathway after chronic unpredictable stress/Z-guggulsterone treatment were investigated. The tryptophan hydroxylase inhibitor and the tyrosine kinase B inhibitor were also used to explore the antidepressant-like mechanisms of Z-guggulsterone. Results: Z-guggulsterone (10, 30 mg/kg) administration protected the mice against the chronic unpredictable stress-induced increases in the immobile time in the tail suspension test and forced swimming test and also reversed the reduction in sucrose intake in sucrose preference experiment. Z-guggulsterone (10, 30 mg/kg) administration prevented the reductions in brain-derived neurotrophic factor protein expression levels as well as the phosphorylation levels of cAMP response element binding protein, extracellular signal-regulated kinase 1/2, and protein kinase B in the hippocampus and cortex induced by chronic unpredictable stress. Z-guggulsterone (10, 30 mg/kg) treatment also improved hippocampal neurogenesis in chronic unpredictable stress-treated mice. Blockade of the brain-derived neurotrophic factor signal, but not the monoaminergic system, attenuated the antidepressant-like effects of Z-guggulsterone. Conclusions: Z-guggulsterone exhibits antidepressant activity via activation of the brain-derived neurotrophic factor signaling pathway and upregulation of hippocampal neurogenesis. PMID:28339691

Branched Chain Amino Acids: Beyond Nutrition Metabolism.

PubMed

Nie, Cunxi; He, Ting; Zhang, Wenju; Zhang, Guolong; Ma, Xi

2018-03-23

Branched chain amino acids (BCAAs), including leucine (Leu), isoleucine (Ile), and valine (Val), play critical roles in the regulation of energy homeostasis, nutrition metabolism, gut health, immunity and disease in humans and animals. As the most abundant of essential amino acids (EAAs), BCAAs are not only the substrates for synthesis of nitrogenous compounds, they also serve as signaling molecules regulating metabolism of glucose, lipid, and protein synthesis, intestinal health, and immunity via special signaling network, especially phosphoinositide 3-kinase/protein kinase B/mammalian target of rapamycin (PI3K/AKT/mTOR) signal pathway. Current evidence supports BCAAs and their derivatives as the potential biomarkers of diseases such as insulin resistance (IR), type 2 diabetes mellitus (T2DM), cancer, and cardiovascular diseases (CVDs). These diseases are closely associated with catabolism and balance of BCAAs. Hence, optimizing dietary BCAA levels should have a positive effect on the parameters associated with health and diseases. This review focuses on recent findings of BCAAs in metabolic pathways and regulation, and underlying the relationship of BCAAs to related disease processes.

Wnt/β-catenin signaling controls development of the blood–brain barrier

PubMed Central

Liebner, Stefan; Corada, Monica; Bangsow, Thorsten; Babbage, Jane; Taddei, Andrea; Czupalla, Cathrin J.; Reis, Marco; Felici, Angelina; Wolburg, Hartwig; Fruttiger, Marcus; Taketo, Makoto M.; von Melchner, Harald; Plate, Karl Heinz; Gerhardt, Holger; Dejana, Elisabetta

2008-01-01

The blood–brain barrier (BBB) is confined to the endothelium of brain capillaries and is indispensable for fluid homeostasis and neuronal function. In this study, we show that endothelial Wnt/β-catenin (β-cat) signaling regulates induction and maintenance of BBB characteristics during embryonic and postnatal development. Endothelial specific stabilization of β-cat in vivo enhances barrier maturation, whereas inactivation of β-cat causes significant down-regulation of claudin3 (Cldn3), up-regulation of plamalemma vesicle-associated protein, and BBB breakdown. Stabilization of β-cat in primary brain endothelial cells (ECs) in vitro by N-terminal truncation or Wnt3a treatment increases Cldn3 expression, BBB-type tight junction formation, and a BBB characteristic gene signature. Loss of β-cat or inhibition of its signaling abrogates this effect. Furthermore, stabilization of β-cat also increased Cldn3 and barrier properties in nonbrain-derived ECs. These findings may open new therapeutic avenues to modulate endothelial barrier function and to limit the devastating effects of BBB breakdown. PMID:18955553

Redox Regulation of Endothelial Cell Fate

PubMed Central

Song, Ping; Zou, Ming-Hui

2014-01-01

Endothelial cells (ECs) are present throughout blood vessels and have variable roles in both physiological and pathological settings. EC fate is altered and regulated by several key factors in physiological or pathological conditions. Reactive nitrogen species and reactive oxygen species derived from NAD(P)H oxidases, mitochondria, or nitric oxide-producing enzymes are not only cytotoxic but also compose a signaling network in the redox system. The formation, actions, key molecular interactions, and physiological and pathological relevance of redox signals in ECs remain unclear. We review the identities, sources, and biological actions of oxidants and reductants produced during EC function or dysfunction. Further, we discuss how ECs shape key redox sensors and examine the biological functions, transcriptional responses, and post-translational modifications evoked by the redox system in ECs. We summarize recent findings regarding the mechanisms by which redox signals regulate the fate of ECs and address the outcome of altered EC fate in health and disease. Future studies will examine if the redox biology of ECs can be targeted in pathophysiological conditions. PMID:24633153

Mycobacterium leprae Activates Toll-Like Receptor-4 Signaling and Expression on Macrophages Depending on Previous Bacillus Calmette-Guerin Vaccination

PubMed Central

Polycarpou, Anastasia; Holland, Martin J.; Karageorgiou, Ioannis; Eddaoudi, Ayad; Walker, Stephen L.; Willcocks, Sam; Lockwood, Diana N. J.

2016-01-01

Toll-like receptor (TLR)-1 and TLR2 have been shown to be receptors for Mycobacterium leprae (M. leprae), yet it is unclear whether M. leprae can signal through alternative TLRs. Other mycobacterial species possess ligands for TLR4 and genetic association studies in human populations suggest that people with TLR4 polymorphisms may be protected against leprosy. Using human embryonic kidney (HEK)-293 cells co-transfected with TLR4, we demonstrate that M. leprae activates TLR4. We used human macrophages to show that M. leprae stimulation of cytokine production is diminished if pre-treated with TLR4 neutralizing antibody. TLR4 protein expression was up-regulated on macrophages derived from non-bacillus Calmette-Guerin (BCG) vaccinated healthy volunteers after incubation with M. leprae, whereas it was down-regulated in macrophages derived from BCG-vaccinated donors. Finally, pre-treatment of macrophages derived from BCG-naive donors with BCG reversed the effect of M. leprae on TLR4 expression. This may be a newly described phenomenon by which BCG vaccination stimulates “non-specific” protection to the human immune system. PMID:27458573

Role of stem cell derived exosomes in tumor biology.

PubMed

Sharma, Aman

2018-03-15

Exosomes are nano-scale messengers loaded with bio-molecular cargo of RNA, DNA, and Proteins. As a master regulator of cellular signaling, stem cell (both normal, and cancer stem cells) secreted exosome orchestrate various autocrine and paracrine functions which alter tumor micro-environment, growth and progression. Exosomes secreted by one of the two important stem cell phenotypes in cancers a) Mesenchymal stem cells, and b) Cancer stem cells not only promote cancerous growth but also impart therapy resistance in cancer cells. In tumors, normal or mesenchymal stem cell (MSCs) derived exosomes (MSC-exo) modulate tumor hallmarks by delivering unique miRNA species to neighboring cells and help in tumor progression. Apart from regulating tumor cell fate, MSC-exo are also capable of inducing physiological processes, for example, angiogenesis, metastasis and so forth. Similarly, cancer stem cells (CSCs) derived exosomes (CSC-exo) contain stemness-specific proteins, self-renewal promoting regulatory miRNAs, and survival factors. CSC-exo specific cargo maintains tumor heterogeneity and alters tumor progression. In this review we critically discuss the importance of stem cell specific exosomes in tumor cell signaling pathways with their role in tumor biology. © 2017 UICC.

Basic Aspects of Tumor Cell Fatty Acid-Regulated Signaling and Transcription Factors

PubMed Central

Comba, Andrea; Lin, Yi-Hui; Eynard, Aldo Renato; Valentich, Mirta Ana; Fernandez-Zapico, Martin Ernesto; Pasqualini, Marìa Eugenia

2012-01-01

This article reviews the current knowledge and experimental research about the mechanisms by which fatty acids and their derivatives control specific gene expression involved during carcinogenesis. Changes in dietary fatty acids, specifically the polyunsaturated fatty acids (PUFAs) of the ω-3 and ω-6 families and some derived eicosanoids from lipoxygenases (LOXs), cyclooxygenases (COXs), and cytochrome P-450 (CYP-450), seem to control the activity of transcription factor families involved in cancer cell proliferation or cell death. Their regulation may be carried out either through direct binding to DNA as peroxisome proliferator–activated receptors (PPARs) or via modulation in an indirect manner of signaling pathway molecules (e.g., protein kinase C [PKC]) and other transcription factors (nuclear factor kappa B [NFκB] and sterol regulatory element binding protein [SREBP]). Knowledge of the mechanisms by which fatty acids control specific gene expression may identify important risk factors for cancer, and provide insight into the development of new therapeutic strategies for a better management of whole-body lipid metabolism. PMID:22048864

Basic aspects of tumor cell fatty acid-regulated signaling and transcription factors.

PubMed

Comba, Andrea; Lin, Yi-Hui; Eynard, Aldo Renato; Valentich, Mirta Ana; Fernandez-Zapico, Martín Ernesto; Pasqualini, Marìa Eugenia

2011-12-01

This article reviews the current knowledge and experimental research about the mechanisms by which fatty acids and their derivatives control specific gene expression involved during carcinogenesis. Changes in dietary fatty acids, specifically the polyunsaturated fatty acids of the ω-3 and ω-6 families and some derived eicosanoids from lipoxygenases, cyclooxygenases, and cytochrome P-450, seem to control the activity of transcription factor families involved in cancer cell proliferation or cell death. Their regulation may be carried out either through direct binding to DNA as peroxisome proliferator-activated receptors or via modulation in an indirect manner of signaling pathway molecules (e.g., protein kinase C) and other transcription factors (nuclear factor kappa B and sterol regulatory element binding protein). Knowledge of the mechanisms by which fatty acids control specific gene expression may identify important risk factors for cancer and provide insight into the development of new therapeutic strategies for a better management of whole body lipid metabolism.

A cellular, molecular, and pharmacological basis for appendage regeneration in mice.

PubMed

Leung, Thomas H; Snyder, Emily R; Liu, Yinghua; Wang, Jing; Kim, Seung K

2015-10-15

Regenerative medicine aims to restore normal tissue architecture and function. However, the basis of tissue regeneration in mammalian solid organs remains undefined. Remarkably, mice lacking p21 fully regenerate injured ears without discernable scarring. Here we show that, in wild-type mice following tissue injury, stromal-derived factor-1 (Sdf1) is up-regulated in the wound epidermis and recruits Cxcr4-expressing leukocytes to the injury site. In p21-deficient mice, Sdf1 up-regulation and the subsequent recruitment of Cxcr4-expressing leukocytes are significantly diminished, thereby permitting scarless appendage regeneration. Lineage tracing demonstrates that this regeneration derives from fate-restricted progenitor cells. Pharmacological or genetic disruption of Sdf1-Cxcr4 signaling enhances tissue repair, including full reconstitution of tissue architecture and all cell types. Our findings identify signaling and cellular mechanisms underlying appendage regeneration in mice and suggest new therapeutic approaches for regenerative medicine. © 2015 Leung et al.; Published by Cold Spring Harbor Laboratory Press.

Aberrant neuronal activity-induced signaling and gene expression in a mouse model of RASopathy

PubMed Central

Nakhaei-Rad, Saeideh; Montenegro-Venegas, Carolina; Pina-Fernández, Eneko; Marini, Claudia; Santos, Monica; Ahmadian, Mohammad R.; Stork, Oliver; Zenker, Martin

2017-01-01

Noonan syndrome (NS) is characterized by reduced growth, craniofacial abnormalities, congenital heart defects, and variable cognitive deficits. NS belongs to the RASopathies, genetic conditions linked to mutations in components and regulators of the Ras signaling pathway. Approximately 50% of NS cases are caused by mutations in PTPN11. However, the molecular mechanisms underlying cognitive impairments in NS patients are still poorly understood. Here, we report the generation and characterization of a new conditional mouse strain that expresses the overactive Ptpn11D61Y allele only in the forebrain. Unlike mice with a global expression of this mutation, this strain is viable and without severe systemic phenotype, but shows lower exploratory activity and reduced memory specificity, which is in line with a causal role of disturbed neuronal Ptpn11 signaling in the development of NS-linked cognitive deficits. To explore the underlying mechanisms we investigated the neuronal activity-regulated Ras signaling in brains and neuronal cultures derived from this model. We observed an altered surface expression and trafficking of synaptic glutamate receptors, which are crucial for hippocampal neuronal plasticity. Furthermore, we show that the neuronal activity-induced ERK signaling, as well as the consecutive regulation of gene expression are strongly perturbed. Microarray-based hippocampal gene expression profiling revealed profound differences in the basal state and upon stimulation of neuronal activity. The neuronal activity-dependent gene regulation was strongly attenuated in Ptpn11D61Y neurons. In silico analysis of functional networks revealed changes in the cellular signaling beyond the dysregulation of Ras/MAPK signaling that is nearly exclusively discussed in the context of NS at present. Importantly, changes in PI3K/AKT/mTOR and JAK/STAT signaling were experimentally confirmed. In summary, this study uncovers aberrant neuronal activity-induced signaling and regulation of gene expression in Ptpn11D61Y mice and suggests that these deficits contribute to the pathophysiology of cognitive impairments in NS. PMID:28346493

An FGF3-BMP Signaling Axis Regulates Caudal Neural Tube Closure, Neural Crest Specification and Anterior-Posterior Axis Extension

PubMed Central

Anderson, Matthew J.; Schimmang, Thomas; Lewandoski, Mark

2016-01-01

During vertebrate axis extension, adjacent tissue layers undergo profound morphological changes: within the neuroepithelium, neural tube closure and neural crest formation are occurring, while within the paraxial mesoderm somites are segmenting from the presomitic mesoderm (PSM). Little is known about the signals between these tissues that regulate their coordinated morphogenesis. Here, we analyze the posterior axis truncation of mouse Fgf3 null homozygotes and demonstrate that the earliest role of PSM-derived FGF3 is to regulate BMP signals in the adjacent neuroepithelium. FGF3 loss causes elevated BMP signals leading to increased neuroepithelium proliferation, delay in neural tube closure and premature neural crest specification. We demonstrate that elevated BMP4 depletes PSM progenitors in vitro, phenocopying the Fgf3 mutant, suggesting that excessive BMP signals cause the Fgf3 axis defect. To test this in vivo we increased BMP signaling in Fgf3 mutants by removing one copy of Noggin, which encodes a BMP antagonist. In such mutants, all parameters of the Fgf3 phenotype were exacerbated: neural tube closure delay, premature neural crest specification, and premature axis termination. Conversely, genetically decreasing BMP signaling in Fgf3 mutants, via loss of BMP receptor activity, alleviates morphological defects. Aberrant apoptosis is observed in the Fgf3 mutant tailbud. However, we demonstrate that cell death does not cause the Fgf3 phenotype: blocking apoptosis via deletion of pro-apoptotic genes surprisingly increases all Fgf3 defects including causing spina bifida. We demonstrate that this counterintuitive consequence of blocking apoptosis is caused by the increased survival of BMP-producing cells in the neuroepithelium. Thus, we show that FGF3 in the caudal vertebrate embryo regulates BMP signaling in the neuroepithelium, which in turn regulates neural tube closure, neural crest specification and axis termination. Uncovering this FGF3-BMP signaling axis is a major advance toward understanding how these tissue layers interact during axis extension with important implications in human disease. PMID:27144312

Neogenin Regulates Skeletal Myofiber Size and Focal Adhesion Kinase and Extracellular Signal-regulated Kinase Activities In Vivo and In Vitro

PubMed Central

Bae, Gyu-Un; Yang, Youn-Joo; Jiang, Guoying; Hong, Mingi; Lee, Hye-Jin; Tessier-Lavigne, Marc

2009-01-01

A variety of signaling pathways participate in the development of skeletal muscle, but the extracellular cues that regulate such pathways in myofiber formation are not well understood. Neogenin is a receptor for ligands of the netrin and repulsive guidance molecule (RGM) families involved in axon guidance. We reported previously that neogenin promoted myotube formation by C2C12 myoblasts in vitro and that the related protein Cdo (also Cdon) was a potential neogenin coreceptor in myoblasts. We report here that mice homozygous for a gene-trap mutation in the Neo1 locus (encoding neogenin) develop myotomes normally but have small myofibers at embryonic day 18.5 and at 3 wk of age. Similarly, cultured myoblasts derived from such animals form smaller myotubes with fewer nuclei than myoblasts from control animals. These in vivo and in vitro defects are associated with low levels of the activated forms of focal adhesion kinase (FAK) and extracellular signal-regulated kinase (ERK), both known to be involved in myotube formation, and inefficient expression of certain muscle-specific proteins. Recombinant netrin-2 activates FAK and ERK in cultured myoblasts in a neogenin- and Cdo-dependent manner, whereas recombinant RGMc displays lesser ability to activate these kinases. Together, netrin-neogenin signaling is an important extracellular cue in regulation of myogenic differentiation and myofiber size. PMID:19812254

Presynaptic Regulation of Leptin in a Defined Lateral Hypothalamus-Ventral Tegmental Area Neurocircuitry Depends on Energy State.

PubMed

Liu, Jing-Jing; Bello, Nicholas T; Pang, Zhiping P

2017-12-06

Synaptic transmission controls brain activity and behaviors, including food intake. Leptin, an adipocyte-derived hormone, acts on neurons located in the lateral hypothalamic area (LHA) to maintain energy homeostasis and regulate food intake behavior. The specific synaptic mechanisms, cell types, and neural projections mediating this effect remain unclear. In male mice, using pathway-specific retrograde tracing, whole-cell patch-clamp recordings and post hoc cell type identification, we found that leptin reduces excitatory synaptic strength onto both melanin-concentrating hormone- and orexin-expressing neurons projecting from the LHA to the ventral tegmental area (VTA), which may affect dopamine signaling and motivation for feeding. A presynaptic mechanism mediated by distinct intracellular signaling mechanisms may account for this regulation by leptin. The regulatory effects of leptin depend on intact leptin receptor signaling. Interestingly, the synaptic regulatory function of leptin in the LHA-to-VTA neuronal pathway is highly sensitive to energy states: both energy deficiency (acute fasting) and excessive energy storage (high-fat diet-induced obesity) blunt the effect of leptin. These data revealed that leptin may regulate synaptic transmission in the LHA-to-VTA neurocircuitry in an inverted "U-shape" fashion dependent on plasma glucose levels and related to metabolic states. SIGNIFICANCE STATEMENT The lateral hypothalamic area (LHA) to ventral tegmental area (VTA) projection is an important neural pathway involved in balancing whole-body energy states and reward. We found that the excitatory synaptic inputs to both orexin- and melanin-concentrating hormone expressing LHA neurons projecting to the VTA were suppressed by leptin, a peptide hormone derived from adipocytes that signals peripheral energy status to the brain. Interestingly, energy states seem to affect how leptin regulates synaptic transmission since both the depletion of energy induced by acute food deprivation and excessive storage of energy by high-fat diet feeding dampen the suppressive effect of leptin on synaptic transmission. Together, these data show that leptin regulates synaptic transmission and might be important for maintaining energy homeostasis. Copyright © 2017 the authors 0270-6474/17/3711854-13$15.00/0.

Tumour-derived SPARC drives vascular permeability and extravasation through endothelial VCAM1 signalling to promote metastasis.

PubMed

Tichet, Mélanie; Prod'Homme, Virginie; Fenouille, Nina; Ambrosetti, Damien; Mallavialle, Aude; Cerezo, Michael; Ohanna, Mickaël; Audebert, Stéphane; Rocchi, Stéphane; Giacchero, Damien; Boukari, Fériel; Allegra, Maryline; Chambard, Jean-Claude; Lacour, Jean-Philippe; Michiels, Jean-François; Borg, Jean-Paul; Deckert, Marcel; Tartare-Deckert, Sophie

2015-04-30

Disruption of the endothelial barrier by tumour-derived secreted factors is a critical step in cancer cell extravasation and metastasis. Here, by comparative proteomic analysis of melanoma secretomes, we identify the matricellular protein SPARC as a novel tumour-derived vascular permeability factor. SPARC deficiency abrogates tumour-initiated permeability of lung capillaries and prevents extravasation, whereas SPARC overexpression enhances vascular leakiness, extravasation and lung metastasis. SPARC-induced paracellular permeability is dependent on the endothelial VCAM1 receptor and p38 MAPK signalling. Blocking VCAM1 impedes melanoma-induced endothelial permeability and extravasation. The clinical relevance of our findings is highlighted by high levels of SPARC detected in tumour from human pulmonary melanoma lesions. Our study establishes tumour-produced SPARC and VCAM1 as regulators of cancer extravasation, revealing a novel targetable interaction for prevention of metastasis.

Regulation of type II transmembrane serine proteinase TMPRSS6 by hypoxia-inducible factors: new link between hypoxia signaling and iron homeostasis.

PubMed

Lakhal, Samira; Schödel, Johannes; Townsend, Alain R M; Pugh, Christopher W; Ratcliffe, Peter J; Mole, David R

2011-02-11

Hepcidin is a liver-derived hormone with a key role in iron homeostasis. In addition to iron, it is regulated by inflammation and hypoxia, although mechanisms of hypoxic regulation remain unclear. In hepatocytes, hepcidin is induced by bone morphogenetic proteins (BMPs) through a receptor complex requiring hemojuvelin (HJV) as a co-receptor. Type II transmembrane serine proteinase (TMPRSS6) antagonizes hepcidin induction by BMPs by cleaving HJV from the cell membrane. Inactivating mutations in TMPRSS6 lead to elevated hepcidin levels and consequent iron deficiency anemia. Here we demonstrate that TMPRSS6 is up-regulated in hepatic cell lines by hypoxia and by other activators of hypoxia-inducible factor (HIF). We show that TMPRSS6 expression is regulated by both HIF-1α and HIF-2α. This HIF-dependent up-regulation of TMPRSS6 increases membrane HJV shedding and decreases hepcidin promoter responsiveness to BMP signaling in hepatocytes. Our results reveal a potential role for TMPRSS6 in hepcidin regulation by hypoxia and provide a new molecular link between oxygen sensing and iron homeostasis.

Gonadotropin and intra-ovarian signals regulating follicle development and atresia: the delicate balance between life and death.

PubMed

Craig, Jesse; Orisaka, Makoto; Wang, Hongmei; Orisaka, Sanae; Thompson, Winston; Zhu, Cheng; Kotsuji, Fumikazu; Tsang, Benjamin K

2007-05-01

Regulation of mammalian follicular development is tightly regulated by both cell death and survival signals, including endocrine (e.g. gonadotropin) and intra-ovarian regulators (e.g. Nodal and GDF9). The destiny of the individual follicle (growth/ovulation or atresia) is dependent on a delicate balance in the expression and action of factors promoting follicular cell proliferation, growth and differentiation, and of those promoting programmed cell death (apoptosis). Development of the follicle from the primordial to preantral stage is regulated by oocyte-derived factors including GDF9 and BMP15, and is not dependent on gonadotropin support (gonadotropin-independent stage). As the follicle transits into the early antral stage it becomes responsive to gonadotropin (gonadotropin-responsive stages) and further development renders the follicle completely dependent on the presence of gonadotropin while modulated by intra-ovarian regulators (gonadotropin-dependent). Follicle fate is also regulated by pro-apoptotic factors such as the intraovarian regulator Nodal, which is secreted by the theca and promotes apoptosis of differentiated granulosa cells through a mechanism involving Smad2 signaling and suppression of the PI3K/Akt pathway. The intracellular protein prohibitin (PHB) appears to have a dual role during folliculogenesis; acting as a cell survival factor in undifferentiated cells, and as a pro-apoptotic factor following differentiation. Further investigations of the interplay between these endocrine and ovarian regulators will lead to a better understanding into the regulation of follicular development and atresia, allowing development of new techniques for assisted reproduction.

Low-frequency transcranial magnetic stimulation is beneficial for enhancing synaptic plasticity in the aging brain.

PubMed

Zhang, Zhan-Chi; Luan, Feng; Xie, Chun-Yan; Geng, Dan-Dan; Wang, Yan-Yong; Ma, Jun

2015-06-01

In the aging brain, cognitive function gradually declines and causes a progressive reduction in the structural and functional plasticity of the hippocampus. Transcranial magnetic stimulation is an emerging and novel neurological and psychiatric tool used to investigate the neurobiology of cognitive function. Recent studies have demonstrated that low-frequency transcranial magnetic stimulation (≤1 Hz) ameliorates synaptic plasticity and spatial cognitive deficits in learning-impaired mice. However, the mechanisms by which this treatment improves these deficits during normal aging are still unknown. Therefore, the current study investigated the effects of transcranial magnetic stimulation on the brain-derived neurotrophic factor signal pathway, synaptic protein markers, and spatial memory behavior in the hippocampus of normal aged mice. The study also investigated the downstream regulator, Fyn kinase, and the downstream effectors, synaptophysin and growth-associated protein 43 (both synaptic markers), to determine the possible mechanisms by which transcranial magnetic stimulation regulates cognitive capacity. Transcranial magnetic stimulation with low intensity (110% average resting motor threshold intensity, 1 Hz) increased mRNA and protein levels of brain-derived neurotrophic factor, tropomyosin receptor kinase B, and Fyn in the hippocampus of aged mice. The treatment also upregulated the mRNA and protein expression of synaptophysin and growth-associated protein 43 in the hippocampus of these mice. In conclusion, brain-derived neurotrophic factor signaling may play an important role in sustaining and regulating structural synaptic plasticity induced by transcranial magnetic stimulation in the hippocampus of aging mice, and Fyn may be critical during this regulation. These responses may change the structural plasticity of the aging hippocampus, thereby improving cognitive function.

Comprehensive proteomic characterization of stem cell-derived extracellular matrices.

PubMed

Ragelle, Héloïse; Naba, Alexandra; Larson, Benjamin L; Zhou, Fangheng; Prijić, Miralem; Whittaker, Charles A; Del Rosario, Amanda; Langer, Robert; Hynes, Richard O; Anderson, Daniel G

2017-06-01

In the stem-cell niche, the extracellular matrix (ECM) serves as a structural support that additionally provides stem cells with signals that contribute to the regulation of stem-cell function, via reciprocal interactions between cells and components of the ECM. Recently, cell-derived ECMs have emerged as in vitro cell culture substrates to better recapitulate the native stem-cell microenvironment outside the body. Significant changes in cell number, morphology and function have been observed when mesenchymal stem cells (MSC) were cultured on ECM substrates as compared to standard tissue-culture polystyrene (TCPS). As select ECM components are known to regulate specific stem-cell functions, a robust characterization of cell-derived ECM proteomic composition is critical to better comprehend the role of the ECM in directing cellular processes. Here, we characterized and compared the protein composition of ECM produced in vitro by bone marrow-derived MSC, adipose-derived MSC and neonatal fibroblasts from different donors, employing quantitative proteomic methods. Each cell-derived ECM displayed a specific and unique matrisome signature, yet they all shared a common set of proteins. We evaluated the biological response of cells cultured on the different matrices and compared them to cells on standard TCPS. The matrices lead to differential survival and gene-expression profiles among the cell types and as compared to TCPS, indicating that the cell-derived ECMs influence each cell type in a different manner. This general approach to understanding the protein composition of different tissue-specific and cell-derived ECM will inform the rational design of defined systems and biomaterials that recapitulate critical ECM signals for stem-cell culture and tissue engineering. Copyright © 2017 Elsevier Ltd. All rights reserved.

Dragon (repulsive guidance molecule b) inhibits IL-6 expression in macrophages.

PubMed

Xia, Yin; Cortez-Retamozo, Virna; Niederkofler, Vera; Salie, Rishard; Chen, Shanzhuo; Samad, Tarek A; Hong, Charles C; Arber, Silvia; Vyas, Jatin M; Weissleder, Ralph; Pittet, Mikael J; Lin, Herbert Y

2011-02-01

Repulsive guidance molecule (RGM) family members RGMa, RGMb/Dragon, and RGMc/hemojuvelin were found recently to act as bone morphogenetic protein (BMP) coreceptors that enhance BMP signaling activity. Although our previous studies have shown that hemojuvelin regulates hepcidin expression and iron metabolism through the BMP pathway, the role of the BMP signaling mediated by Dragon remains largely unknown. We have shown previously that Dragon is expressed in neural cells, germ cells, and renal epithelial cells. In this study, we demonstrate that Dragon is highly expressed in macrophages. Studies with RAW264.7 and J774 macrophage cell lines reveal that Dragon negatively regulates IL-6 expression in a BMP ligand-dependent manner via the p38 MAPK and Erk1/2 pathways but not the Smad1/5/8 pathway. We also generated Dragon knockout mice and found that IL-6 is upregulated in macrophages and dendritic cells derived from whole lung tissue of these mice compared with that in respective cells derived from wild-type littermates. These results indicate that Dragon is an important negative regulator of IL-6 expression in immune cells and that Dragon-deficient mice may be a useful model for studying immune and inflammatory disorders.

Drosophila nemo is an essential gene involved in the regulation of programmed cell death.

PubMed

Mirkovic, Ivana; Charish, Kristi; Gorski, Sharon M; McKnight, Kristen; Verheyen, Esther M

2002-11-01

Nemo-like kinases define a novel family of serine/threonine kinases that are involved in integrating multiple signaling pathways. They are conserved regulators of Wnt/Wingless pathways, which may coordinate Wnt with TGFbeta-mediated signaling. Drosophila nemo was identified through its involvement in epithelial planar polarity, a process regulated by a non-canonical Wnt pathway. We have previously found that ectopic expression of Nemo using the Gal4-UAS system resulted in embryonic lethality associated with defects in patterning and head development. In this study we present our analyses of the phenotypes of germline clone-derived embryos. We observe lethality associated with head defects and reduction of programmed cell death and conclude that nmo is an essential gene. We also present data showing that nmo is involved in regulating apoptosis during eye development, based on both loss of function phenotypes and on genetic interactions with the pro-apoptotic gene reaper. Finally, we present genetic data from the adult wing that suggest the activity of ectopically expressed Nemo can be modulated by Jun N-terminal kinase (JNK) signaling. Such an observation supports the model that there is cross-talk between Wnt, TGFbeta and JNK signaling at multiple stages of development. Copyright 2002 Elsevier Science Ireland Ltd.

Computational Discovery of Niclosamide Ethanolamine, a Repurposed Drug Candidate That Reduces Growth of Hepatocellular Carcinoma Cells In Vitro and in Mice by Inhibiting Cell Division Cycle 37 Signaling.

PubMed

Chen, Bin; Wei, Wei; Ma, Li; Yang, Bin; Gill, Ryan M; Chua, Mei-Sze; Butte, Atul J; So, Samuel

2017-06-01

Drug repositioning offers a shorter approval process than new drug development. We therefore searched large public datasets of drug-induced gene expression signatures to identify agents that might be effective against hepatocellular carcinoma (HCC). We searched public databases of messenger RNA expression patterns reported from HCC specimens from patients, HCC cell lines, and cells exposed to various drugs. We identified drugs that might specifically increase expression of genes that are down-regulated in HCCs and reduce expression of genes up-regulated in HCCs using a nonparametric, rank-based pattern-matching strategy based on the Kolmogorov-Smirnov statistic. We evaluated the anti-tumor activity of niclosamide and its ethanolamine salt (NEN) in HCC cell lines (HepG2, Huh7, Hep3B, Hep40, and PLC/PRF/5), primary human hepatocytes, and 2 mouse models of HCC. In one model of HCC, liver tumor development was induced by hydrodynamic delivery of a sleeping beauty transposon expressing an activated form of Ras (v12) and truncated β-catenin (N90). In another mouse model, patient-derived xenografts were established by implanting HCC cells from patients into livers of immunocompromised mice. Tumor growth was monitored by bioluminescence imaging. Tumor-bearing mice were fed a regular chow diet or a chow diet containing niclosamide or NEN. In a separate experiment using patient-derived xenografts, tumor-bearing mice were given sorafenib (the standard of care for patients with advanced HCC), NEN, or niclosamide alone; a combination of sorafenib and NEN; or a combination sorafenib and niclosamide in their drinking water, or regular water (control), and tumor growth was monitored. Based on gene expression signatures, we identified 3 anthelmintics that significantly altered the expression of genes that are up- or down-regulated in HCCs. Niclosamide and NEN specifically reduced the viability of HCC cells: the agents were at least 7-fold more cytotoxic to HCCs than primary hepatocytes. Oral administration of NEN to mice significantly slowed growth of genetically induced liver tumors and patient-derived xenografts, whereas niclosamide did not, coinciding with the observed greater bioavailability of NEN compared with niclosamide. The combination of NEN and sorafenib was more effective at slowing growth of patient-derived xenografts than either agent alone. In HepG2 cells and in patient-derived xenografts, administration of niclosamide or NEN increased expression of 20 genes down-regulated in HCC and reduced expression of 29 genes up-regulated in the 274-gene HCC signature. Administration of NEN to mice with patient-derived xenografts reduced expression of proteins in the Wnt-β-catenin, signal transducer and activator of transcription 3, AKT-mechanistic target of rapamycin, epidermal growth factor receptor-Ras-Raf signaling pathways. Using immunoprecipitation assays, we found NEN to bind cell division cycle 37 protein and disrupt its interaction with heat shock protein 90. In a bioinformatics search for agents that alter the HCC-specific gene expression pattern, we identified the anthelmintic niclosamide as a potential anti-tumor agent. Its ethanolamine salt, with greater bioavailability, was more effective than niclosamide at slowing the growth of genetically induced liver tumors and patient-derived xenografts in mice. Both agents disrupted interaction between cell division cycle 37 and heat shock protein 90 in HCC cells, with concomitant inhibition of their downstream signaling pathways. NEN might be effective for treatment of patients with HCC. Copyright © 2017 AGA Institute. Published by Elsevier Inc. All rights reserved.

ACTIVITY-DEPENDENT, STRESS-RESPONSIVE BDNF SIGNALING AND THE QUEST FOR OPTIMAL BRAIN HEALTH AND RESILIENCE THROUGHOUT THE LIFESPAN

PubMed Central

Rothman, S. M.; Mattson, M. P.

2013-01-01

During development of the nervous system, the formation of connections (synapses) between neurons is dependent upon electrical activity in those neurons, and neurotrophic factors produced by target cells play a pivotal role in such activity-dependent sculpting of the neural networks. A similar interplay between neurotransmitter and neurotrophic factor signaling pathways mediates adaptive responses of neural networks to environmental demands in adult mammals, with the excitatory neurotransmitter glutamate and brain-derived neurotrophic factor (BDNF) being particularly prominent regulators of synaptic plasticity throughout the central nervous system. Optimal brain health throughout the lifespan is promoted by intermittent challenges such as exercise, cognitive stimulation and dietary energy restriction, that subject neurons to activity-related metabolic stress. At the molecular level, such challenges to neurons result in the production of proteins involved in neurogenesis, learning and memory and neuronal survival; examples include proteins that regulate mitochondrial biogenesis, protein quality control, and resistance of cells to oxidative, metabolic and proteotoxic stress. BDNF signaling mediates up-regulation of several such proteins including the protein chaperone GRP-78, antioxidant enzymes, the cell survival protein Bcl-2, and the DNA repair enzyme APE1. Insufficient exposure to such challenges, genetic factors may conspire to impair BDNF production and/or signaling resulting in the vulnerability of the brain to injury and neurodegenerative disorders including Alzheimer’s, Parkinson’s and Huntington’s diseases. Further, BDNF signaling is negatively regulated by glucocorticoids. Glucocorticoids impair synaptic plasticity in the brain by negatively regulating spine density, neurogenesis and long-term potentiation, effects that are potentially linked to glucocorticoid regulation of BDNF. Findings suggest that BDNF signaling in specific brain regions mediates some of the beneficial effects of exercise and energy restriction on peripheral energy metabolism and the cardiovascular system. Collectively, the findings described in this article suggest the possibility of developing prescriptions for optimal brain health based on activity-dependent BDNF signaling. PMID:23079624

Top hits in contemporary JAZ: New information on jasmonate signaling

PubMed Central

Chung, Hoo Sun; Niu, Yajie; Browse, John; Howe, Gregg A.

2012-01-01

The phytohormone jasmonate (JA) regulates a wide range of growth, developmental, and defense-related processes during the plant life cycle. Identification of the JAZ family of proteins that repress JA responses has facilitated rapid progress in understanding how this lipid-derived hormone controls gene expression. Recent analysis of JAZ proteins has provided new insight into the nature of the JA receptor, the chemical specificity of signal perception, and cross-talk between JA and other hormone response pathways. Functional diversification of JAZ proteins by alternative splicing, together with the ability of JAZ proteins to homo- and heterodimerize, provide mechanisms to enhance combinatorial diversity and versatility in gene regulation by JA. PMID:19800644

Target-Derived Neurotrophins Coordinate Transcription and Transport of Bclw to Prevent Axonal Degeneration

PubMed Central

Cosker, Katharina E.; Pazyra-Murphy, Maria F.; Fenstermacher, Sara J.

2013-01-01

Establishment of neuronal circuitry depends on both formation and refinement of neural connections. During this process, target-derived neurotrophins regulate both transcription and translation to enable selective axon survival or elimination. However, it is not known whether retrograde signaling pathways that control transcription are coordinated with neurotrophin-regulated actions that transpire in the axon. Here we report that target-derived neurotrophins coordinate transcription of the antiapoptotic gene bclw with transport of bclw mRNA to the axon, and thereby prevent axonal degeneration in rat and mouse sensory neurons. We show that neurotrophin stimulation of nerve terminals elicits new bclw transcripts that are immediately transported to the axons and translated into protein. Bclw interacts with Bax and suppresses the caspase6 apoptotic cascade that fosters axonal degeneration. The scope of bclw regulation at the levels of transcription, transport, and translation provides a mechanism whereby sustained neurotrophin stimulation can be integrated over time, so that axonal survival is restricted to neurons connected within a stable circuit. PMID:23516285

VGF and Its C-Terminal Peptide TLQP-62 Regulate Memory Formation in Hippocampus via a BDNF-TrkB-Dependent Mechanism.

PubMed

Lin, Wei-Jye; Jiang, Cheng; Sadahiro, Masato; Bozdagi, Ozlem; Vulchanova, Lucy; Alberini, Cristina M; Salton, Stephen R

2015-07-15

Regulated expression and secretion of BDNF, which activates TrkB receptor signaling, is known to play a critical role in cognition. Identification of additional modulators of cognitive behavior that regulate activity-dependent BDNF secretion and/or potentiate TrkB receptor signaling would therefore be of considerable interest. In this study, we show in the adult mouse hippocampus that expression of the granin family gene Vgf and secretion of its C-terminal VGF-derived peptide TLQP-62 are required for fear memory formation. We found that hippocampal VGF expression and TLQP-62 levels were transiently induced after fear memory training and that sequestering secreted TLQP-62 peptide in the hippocampus immediately after training impaired memory formation. Reduced VGF expression was found to impair learning-evoked Rac1 induction and phosphorylation of the synaptic plasticity markers cofilin and synapsin in the adult mouse hippocampus. Moreover, TLQP-62 induced acute, transient activation of the TrkB receptor and subsequent CREB phosphorylation in hippocampal slice preparations and its administration immediately after training enhanced long-term memory formation. A critical role of BDNF-TrkB signaling as a downstream effector in VGF/TLQP-62-mediated memory consolidation was further revealed by posttraining activation of BDNF-TrkB signaling, which rescued impaired fear memory resulting from hippocampal administration of anti-VGF antibodies or germline VGF ablation in mice. We propose that VGF is a critical component of a positive BDNF-TrkB regulatory loop and, upon its induced expression by memory training, the TLQP-62 peptide rapidly reinforces BDNF-TrkB signaling, regulating hippocampal memory consolidation. Identification of the cellular and molecular mechanisms that regulate long-term memory formation and storage may provide alternative treatment modalities for degenerative and neuropsychiatric memory disorders. The neurotrophin BDNF plays a prominent role in cognitive function, and rapidly and robustly induces expression of VGF, a secreted neuronal peptide precursor. VGF knock-out mice have impaired fear and spatial memory. Our study shows that VGF and VGF-derived peptide TLQP-62 are transiently induced after fear memory training, leading to increased BDNF/TrkB signaling, and that sequestration of hippocampal TLQP-62 immediately after training impairs memory formation. We propose that TLQP-62 is a critical component of a positive regulatory loop that is induced by memory training, rapidly reinforces BDNF-TrkB signaling, and is required for hippocampal memory consolidation. Copyright © 2015 the authors 0270-6474/15/3510344-14$15.00/0.

VGF and Its C-Terminal Peptide TLQP-62 Regulate Memory Formation in Hippocampus via a BDNF-TrkB-Dependent Mechanism

PubMed Central

Lin, Wei-Jye; Jiang, Cheng; Sadahiro, Masato; Bozdagi, Ozlem; Vulchanova, Lucy; Alberini, Cristina M.

2015-01-01

Regulated expression and secretion of BDNF, which activates TrkB receptor signaling, is known to play a critical role in cognition. Identification of additional modulators of cognitive behavior that regulate activity-dependent BDNF secretion and/or potentiate TrkB receptor signaling would therefore be of considerable interest. In this study, we show in the adult mouse hippocampus that expression of the granin family gene Vgf and secretion of its C-terminal VGF-derived peptide TLQP-62 are required for fear memory formation. We found that hippocampal VGF expression and TLQP-62 levels were transiently induced after fear memory training and that sequestering secreted TLQP-62 peptide in the hippocampus immediately after training impaired memory formation. Reduced VGF expression was found to impair learning-evoked Rac1 induction and phosphorylation of the synaptic plasticity markers cofilin and synapsin in the adult mouse hippocampus. Moreover, TLQP-62 induced acute, transient activation of the TrkB receptor and subsequent CREB phosphorylation in hippocampal slice preparations and its administration immediately after training enhanced long-term memory formation. A critical role of BDNF-TrkB signaling as a downstream effector in VGF/TLQP-62-mediated memory consolidation was further revealed by posttraining activation of BDNF-TrkB signaling, which rescued impaired fear memory resulting from hippocampal administration of anti-VGF antibodies or germline VGF ablation in mice. We propose that VGF is a critical component of a positive BDNF-TrkB regulatory loop and, upon its induced expression by memory training, the TLQP-62 peptide rapidly reinforces BDNF-TrkB signaling, regulating hippocampal memory consolidation. SIGNIFICANCE STATEMENT Identification of the cellular and molecular mechanisms that regulate long-term memory formation and storage may provide alternative treatment modalities for degenerative and neuropsychiatric memory disorders. The neurotrophin BDNF plays a prominent role in cognitive function, and rapidly and robustly induces expression of VGF, a secreted neuronal peptide precursor. VGF knock-out mice have impaired fear and spatial memory. Our study shows that VGF and VGF-derived peptide TLQP-62 are transiently induced after fear memory training, leading to increased BDNF/TrkB signaling, and that sequestration of hippocampal TLQP-62 immediately after training impairs memory formation. We propose that TLQP-62 is a critical component of a positive regulatory loop that is induced by memory training, rapidly reinforces BDNF-TrkB signaling, and is required for hippocampal memory consolidation. PMID:26180209

Targets of B-cell antigen receptor signaling: the phosphatidylinositol 3-kinase/Akt/glycogen synthase kinase-3 signaling pathway and the Rap1 GTPase.

PubMed

Gold, M R; Ingham, R J; McLeod, S J; Christian, S L; Scheid, M P; Duronio, V; Santos, L; Matsuuchi, L

2000-08-01

In this review, we discuss the role of phosphatidylinositol 3-kinase (PI3K) and Rap 1 in B-cell receptor (BCR) signaling. PI3K produces lipids that recruit pleckstrin homology domain-containing proteins to the plasma membrane. Akt is a kinase that the BCR activates in this manner. Akt phosphorylates several transcription factors as well as proteins that regulate apoptosis and protein synthesis. Akt also regulates glycogen synthase kinase-3, a kinase whose substrates include the nuclear factor of activated T cells (NF-AT)cl and beta-catenin transcriptional activators. In addition to Akt, PI3K-derived lipids also regulate the activity and localization of other targets of BCR signaling. Thus, a key event in BCR signaling is the recruitment of PI3K to the plasma membrane where its substrates are located. This is mediated by binding of the Src homology (SH) 2 domains in PI3K to phosphotyrosine-containing sequences on membrane-associated docking proteins. The docking proteins that the BCR uses to recruit PI3K include CD19, Cbl, Gab1, and perhaps Gab2. We have shown that Gab1 colocalizes PI3K with SH2 domain-containing inositol phosphatase (SHIP) and SHP2, two enzymes that regulate PI3K-dependent signaling. In contrast to PI3K, little is known about the Rap1 GTPase. We showed that the BCR activates Rap1 via phospholipase C-dependent production of diacylglycerol. Since Rap1 is thought to regulate cell adhesion and cell polarity, it may be involved in B-cell migration.

Use of Human Induced Pluripotent Stem Cell-Derived Cardiomyocytes (hiPSC-CMs) to Monitor Compound Effects on Cardiac Myocyte Signaling Pathways.

PubMed

Guo, Liang; Eldridge, Sandy; Furniss, Mike; Mussio, Jodie; Davis, Myrtle

2015-09-01

There is a need to develop mechanism-based assays to better inform risk of cardiotoxicity. Human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) are rapidly gaining acceptance as a biologically relevant in vitro model for use in drug discovery and cardiotoxicity screens. Utilization of hiPSC-CMs for mechanistic investigations would benefit from confirmation of the expression and activity of cellular pathways that are known to regulate cardiac myocyte viability and function. This unit describes an approach to demonstrate the presence and function of signaling pathways in hiPSC-CMs and the effects of treatments on these pathways. We present a workflow that employs protocols to demonstrate protein expression and functional integrity of signaling pathway(s) of interest and to characterize biological consequences of signaling modulation. These protocols utilize a unique combination of structural, functional, and biochemical endpoints to interrogate compound effects on cardiomyocytes. Copyright © 2015 John Wiley & Sons, Inc.

Extinction of aversive memories associated with morphine withdrawal requires ERK-mediated epigenetic regulation of brain-derived neurotrophic factor transcription in the rat ventromedial prefrontal cortex.

PubMed

Wang, Wei-Sheng; Kang, Shuo; Liu, Wen-Tao; Li, Mu; Liu, Yao; Yu, Chuan; Chen, Jie; Chi, Zhi-Qiang; He, Ling; Liu, Jing-Gen

2012-10-03

Recent evidence suggests that histone deacetylase (HDAC) inhibitors facilitate extinction of rewarding memory of drug taking. However, little is known about the role of chromatin modification in the extinction of aversive memory of drug withdrawal. In this study, we used conditioned place aversion (CPA), a highly sensitive model for measuring aversive memory of drug withdrawal, to investigate the role of epigenetic regulation of brain-derived neurotrophic factor (BDNF) gene expression in extinction of aversive memory. We found that CPA extinction training induced an increase in recruiting cAMP response element-binding protein (CREB) to and acetylation of histone H3 at the promoters of BDNF exon I transcript and increased BDNF mRNA and protein expression in the ventromedial prefrontal cortex (vmPFC) of acute morphine-dependent rats and that such epigenetic regulation of BDNF gene transcription could be facilitated or diminished by intra-vmPFC infusion of HDAC inhibitor trichostatin A or extracellular signal-regulated kinase (ERK) inhibitor U0126 (1,4-diamino-2,3-dicyano-1,4-bis(methylthio)butadiene) before extinction training. Correspondingly, disruption of the epigenetic regulation of BDNF gene transcription with U0126 or suppression of BDNF signaling with Trk receptor antagonist K252a or BDNF scavenger tyrosine kinase receptor B (TrkB)-Fc blocked extinction of CPA behavior. We also found that extinction training-induced activation of ERK and CREB and extinction of CPA behavior could be potentiated or suppressed by intra-vmPFC infusion of d-cycloserine, a NMDA receptor partial agonist or aminophosphonopentanoic acid, a NMDA receptor antagonist. We conclude that extinction of aversive memory of morphine withdrawal requires epigenetic regulation of BDNF gene transcription in the vmPFC through activation of the ERK-CREB signaling pathway perhaps in a NMDA receptor-dependent manner.

Regulation of NF-κB-Induced Inflammatory Signaling by Lipid Peroxidation-Derived Aldehydes

PubMed Central

Yadav, Umesh C. S.; Ramana, Kota V.

2013-01-01

Oxidative stress plays a critical role in the pathophysiology of a wide range of diseases including cancer. This view has broadened significantly with the recent discoveries that reactive oxygen species initiated lipid peroxidation leads to the formation of potentially toxic lipid aldehyde species such as 4-hydroxy-trans-2-nonenal (HNE), acrolein, and malondialdehyde which activate various signaling intermediates that regulate cellular activity and dysfunction via a process called redox signaling. The lipid aldehyde species formed during synchronized enzymatic pathways result in the posttranslational modification of proteins and DNA leading to cytotoxicity and genotoxicty. Among the lipid aldehyde species, HNE has been widely accepted as a most toxic and abundant lipid aldehyde generated during lipid peroxidation. HNE and its glutathione conjugates have been shown to regulate redox-sensitive transcription factors such as NF-κB and AP-1 via signaling through various protein kinase cascades. Activation of redox-sensitive transcription factors and their nuclear localization leads to transcriptional induction of several genes responsible for cell survival, differentiation, and death. In this review, we describe the mechanisms by which the lipid aldehydes transduce activation of NF-κB signaling pathways that may help to develop therapeutic strategies for the prevention of a number of inflammatory diseases. PMID:23710287

Group 3 Innate Lymphoid Cells: Communications Hubs of the Intestinal Immune System.

PubMed

Withers, David R; Hepworth, Matthew R

2017-01-01

The maintenance of mammalian health requires the generation of appropriate immune responses against a broad range of environmental and microbial challenges, which are continually encountered at barrier tissue sites including the skin, lung, and gastrointestinal tract. Dysregulated barrier immune responses result in inflammation, both locally and systemically in peripheral organs. Group 3 innate lymphoid cells (ILC3) are constitutively present at barrier sites and appear to be highly specialized in their ability to sense a range of environmental and host-derived signals. Under homeostatic conditions, ILC3 respond to local cues to maintain tissue homeostasis and restrict inflammatory responses. In contrast, perturbations in the tissue microenvironment resulting from disease, infection, or tissue damage can drive dysregulated pro-inflammatory ILC3 responses and contribute to immunopathology. The tone of the ILC3 response is dictated by a balance of "exogenous" signals, such as dietary metabolites and commensal microbes, and "endogenous" host-derived signals from stromal cells, immune cells, and the nervous system. ILC3 must therefore have the capacity to simultaneously integrate a wide array of complex and dynamic inputs in order to regulate barrier function and tissue health. In this review, we discuss the concept of ILC3 as a "communications hub" in the intestinal tract and associated lymphoid tissues and address the variety of signals, derived from multiple biological systems, which are interpreted by ILC3 to modulate the release of downstream effector molecules and regulate cell-cell crosstalk. Successful integration of environmental cues by ILC3 and downstream propagation to the broader immune system is required to maintain a tolerogenic and anti-inflammatory tone and reinforce barrier function, whereas dysregulation of ILC3 responses can contribute to the onset or progression of clinically relevant chronic inflammatory diseases.

Group 3 Innate Lymphoid Cells: Communications Hubs of the Intestinal Immune System

PubMed Central

Withers, David R.; Hepworth, Matthew R.

2017-01-01

The maintenance of mammalian health requires the generation of appropriate immune responses against a broad range of environmental and microbial challenges, which are continually encountered at barrier tissue sites including the skin, lung, and gastrointestinal tract. Dysregulated barrier immune responses result in inflammation, both locally and systemically in peripheral organs. Group 3 innate lymphoid cells (ILC3) are constitutively present at barrier sites and appear to be highly specialized in their ability to sense a range of environmental and host-derived signals. Under homeostatic conditions, ILC3 respond to local cues to maintain tissue homeostasis and restrict inflammatory responses. In contrast, perturbations in the tissue microenvironment resulting from disease, infection, or tissue damage can drive dysregulated pro-inflammatory ILC3 responses and contribute to immunopathology. The tone of the ILC3 response is dictated by a balance of “exogenous” signals, such as dietary metabolites and commensal microbes, and “endogenous” host-derived signals from stromal cells, immune cells, and the nervous system. ILC3 must therefore have the capacity to simultaneously integrate a wide array of complex and dynamic inputs in order to regulate barrier function and tissue health. In this review, we discuss the concept of ILC3 as a “communications hub” in the intestinal tract and associated lymphoid tissues and address the variety of signals, derived from multiple biological systems, which are interpreted by ILC3 to modulate the release of downstream effector molecules and regulate cell–cell crosstalk. Successful integration of environmental cues by ILC3 and downstream propagation to the broader immune system is required to maintain a tolerogenic and anti-inflammatory tone and reinforce barrier function, whereas dysregulation of ILC3 responses can contribute to the onset or progression of clinically relevant chronic inflammatory diseases. PMID:29085366

Bone Morphogenetic Protein Regulation of Enteric Neuronal Phenotypic Diversity: Relationship to Timing of Cell Cycle Exit

PubMed Central

Chalazonitis, Alcmène; Pham, Tuan.D.; Li, Zhishan; Roman, Daniel; Guha, Udayan; Gomes, William; Kan, Lixin; Kessler, John A.; Gershon, Michael D.

2008-01-01

The effects of bone morphogenetic protein (BMP) signaling on enteric neuron development were examined in transgenic mice over expressing either the BMP inhibitor, noggin, or BMP4 under control of the neuron specific enolase (NSE) promoter. Noggin antagonism of BMP signaling increased total numbers of enteric neurons and those of subpopulations derived from precursors that exit the cell cycle early in neurogenesis (serotonin, calretinin, calbindin). In contrast, noggin overexpression decreased numbers of neurons derived from precursors that exit the cell cycle late (γ-aminobutyric acid, tyrosine hydroxylase [TH], dopamine transporter, calcitonin gene related peptide, TrkC). Numbers of TH- and TrkC-expressing neurons were increased by overexpression of BMP4. These observations are consistent with the idea that phenotypic expression in the enteric nervous system (ENS) is determined, in part, by the number of proliferative divisions neuronal precursors undergo before their terminal mitosis. BMP signaling may thus regulate enteric neuronal phenotypic diversity by promoting the exit of precursors from the cell cycle. BMP2 increased the numbers of TH- and TrkC-expressing neurons developing in vitro from immunoselected enteric crest-derived precursors; BMP signaling may thus also specify or promote the development of dopaminergic TrkC/NT-3-dependent neurons. The developmental defects in the ENS of noggin overexpressing mice caused a relatively mild disturbance of motility (irregular rapid transit and increased stool frequency, weight, and water content). Although the function of the gut thus displays a remarkable tolerance for ENS defects, subtle functional abnormalities in motility or secretion may arise when ENS defects short of aganglionosis occur during development. PMID:18537141

Plant elicitor peptides are conserved signals regulating direct and indirect antiherbivore defense

PubMed Central

Huffaker, Alisa; Pearce, Gregory; Veyrat, Nathalie; Erb, Matthias; Turlings, Ted C. J.; Sartor, Ryan; Shen, Zhouxin; Briggs, Steven P.; Vaughan, Martha M.; Alborn, Hans T.; Teal, Peter E. A.; Schmelz, Eric A.

2013-01-01

Insect-induced defenses occur in nearly all plants and are regulated by conserved signaling pathways. As the first described plant peptide signal, systemin regulates antiherbivore defenses in the Solanaceae, but in other plant families, peptides with analogous activity have remained elusive. In the current study, we demonstrate that a member of the maize (Zea mays) plant elicitor peptide (Pep) family, ZmPep3, regulates responses against herbivores. Consistent with being a signal, expression of the ZmPROPEP3 precursor gene is rapidly induced by Spodoptera exigua oral secretions. At concentrations starting at 5 pmol per leaf, ZmPep3 stimulates production of jasmonic acid, ethylene, and increased expression of genes encoding proteins associated with herbivory defense. These include proteinase inhibitors and biosynthetic enzymes for production of volatile terpenes and benzoxazinoids. In accordance with gene expression data, plants treated with ZmPep3 emit volatiles similar to those from plants subjected to herbivory. ZmPep3-treated plants also exhibit induced accumulation of the benzoxazinoid phytoalexin 2-hydroxy-4,7-dimethoxy-1,4-benzoxazin-3-one glucoside. Direct and indirect defenses induced by ZmPep3 contribute to resistance against S. exigua through significant reduction of larval growth and attraction of Cotesia marginiventris parasitoids. ZmPep3 activity is specific to Poaceous species; however, peptides derived from PROPEP orthologs identified in Solanaceous and Fabaceous plants also induce herbivory-associated volatiles in their respective species. These studies demonstrate that Peps are conserved signals across diverse plant families regulating antiherbivore defenses and are likely to be the missing functional homologs of systemin outside of the Solanaceae. PMID:23509266

Transcriptional regulation of cranial sensory placode development

PubMed Central

Moody, Sally A.; LaMantia, Anthony-Samuel

2015-01-01

Cranial sensory placodes derive from discrete patches of the head ectoderm, and give rise to numerous sensory structures. During gastrulation, a specialized “neural border zone” forms around the neural plate in response to interactions between the neural and non-neural ectoderm and signals from adjacent mesodermal and/or endodermal tissues. This zone subsequently gives rise to two distinct precursor populations of the peripheral nervous system: the neural crest and the pre-placodal ectoderm (PPE). The PPE is a common field from which all cranial sensory placodes arise (adenohypophyseal, olfactory, lens, trigeminal, epibranchial, otic). Members of the Six family of transcription factors are major regulators of PPE specification, in partnership with co-factor proteins such as Eya. Six gene activity also maintains tissue boundaries between the PPE, neural crest and epidermis by repressing genes that specify the fates of those adjacent ectodermally-derived domains. As the embryo acquires anterior-posterior identity, the PPE becomes transcriptionally regionalized, and it subsequently subdivides into specific placodes with distinct developmental fates in response to signaling from adjacent tissues. Each placode is characterized by a unique transcriptional program that leads to the differentiation of highly specialized cells, such as neurosecretory cells, somatic sensory receptor cells, chemosensory neurons, peripheral glia and supporting cells. In this review, we summarize the transcriptional and signaling factors that regulate key steps of placode development, influence subsequent sensory neuron specification, and discuss what is known about mutations in some of the essential PPE genes that underlie human congenital syndromes. PMID:25662264

Long-chain bases and their phosphorylated derivatives differentially regulate cryptogein-induced production of reactive oxygen species in tobacco (Nicotiana tabacum) BY-2 cells.

PubMed

Coursol, Sylvie; Fromentin, Jérôme; Noirot, Elodie; Brière, Christian; Robert, Franck; Morel, Johanne; Liang, Yun-Kuan; Lherminier, Jeannine; Simon-Plas, Françoise

2015-02-01

The proteinaceous elicitor cryptogein triggers defence reactions in Nicotiana tabacum (tobacco) through a signalling cascade, including the early production of reactive oxygen species (ROS) by the plasma membrane (PM)-located tobacco respiratory burst oxidase homologue D (NtRbohD). Sphingolipid long-chain bases (LCBs) are emerging as potent positive regulators of plant defence-related mechanisms. This led us to question whether both LCBs and their phosphorylated derivatives (LCB-Ps) are involved in the early signalling process triggered by cryptogein in tobacco BY-2 cells. Here, we showed that cryptogein-induced ROS production was inhibited by LCB kinase (LCBK) inhibitors. Additionally, Arabidopsis thaliana sphingosine kinase 1 and exogenously supplied LCB-Ps increased cryptogein-induced ROS production, whereas exogenously supplied LCBs had a strong opposite effect, which was not driven by a reduction in cellular viability. Immunogold-electron microscopy assay also revealed that LCB-Ps are present in the PM, which fits well with the presence of a high LCBK activity associated with this fraction. Our data demonstrate that LCBs and LCB-Ps differentially regulate cryptogein-induced ROS production in tobacco BY-2 cells, and support a model in which a cooperative synergism between LCBK/LCB-Ps and NtRbohD/ROS in the cryptogein signalling pathway is likely at the PM in tobacco BY-2 cells. © 2014 INRA New Phytologist © 2014 New Phytologist Trust.

Synergistic Effect of TPD7 and Berberine against Leukemia Jurkat Cell Growth through Regulating Ephrin-B2 Signaling.

PubMed

Ma, Weina; Zhu, Man; Yang, Liu; Yang, Tianfeng; Zhang, Yanmin

2017-09-01

TPD7, a novel biphenyl urea taspine derivative, and berberine have presented inhibition on VEGFR2 that can be regulated by ephrin-B2 reverse signaling through interactions with the PDZ domain. The purpose of this study is to investigate the inhibitory effect of the combination of TPD7 and berberine (TAB) on T-cell acute lymphoblastic leukemia cell growth. TPD7 and berberine together synergistically inhibited the proliferation of Jurkat cells. Also, the combination of TAB induced G 1 -phase cell-cycle arrest by downregulating the level of cyclin D1, cyclin E, and CDC2. Furthermore, the combination of TAB significantly enhanced apoptosis in Jurkat cells, and the apoptosis most likely resulted from the modulation of the level of Bcl-2 family members. Most importantly, the concomitant treatment simultaneously regulated the ephrin-B2 and VEGFR2 signaling, as well as modulated the MEK/ERK and PTEN/PI3K/AKT/mTOR signaling. Therefore, the combination treatment of TAB may be a promising therapeutic method in treating T-cell acute lymphoblastic leukemia. Copyright © 2017 John Wiley & Sons, Ltd. Copyright © 2017 John Wiley & Sons, Ltd.

Stress, epigenetics, and alcoholism.

PubMed

Moonat, Sachin; Pandey, Subhash C

2012-01-01

Acute and chronic stressors have been associated with alterations in mood and increased anxiety that may eventually result in the development of stress-related psychiatric disorders. Stress and associated disorders, including anxiety, are key factors in the development of alcoholism because alcohol consumption can temporarily reduce the drinker's dysphoria. One molecule that may help mediate the relationship between stress and alcohol consumption is brain-derived neurotrophic factor (BDNF), a protein that regulates the structure and function of the sites where two nerve cells interact and exchange nerve signals (i.e., synapses) and which is involved in numerous physiological processes. Aberrant regulation of BDNF signaling and alterations in synapse activity (i.e., synaptic plasticity) have been associated with the pathophysiology of stress-related disorders and alcoholism. Mechanisms that contribute to the regulation of genetic information without modification of the DNA sequence (i.e., epigenetic mechanisms) may play a role in the complex control of BDNF signaling and synaptic plasticity-for example, by modifying the structure of the DNA-protein complexes (i.e., chromatin) that make up the chromosomes and thereby modulating the expression of certain genes. Studies regarding the epigenetic control of BDNF signaling and synaptic plasticity provide a promising direction to understand the mechanisms mediating the interaction between stress and alcoholism.

BMPs and FGFs target Notch signalling via jagged 2 to regulate tooth morphogenesis and cytodifferentiation

PubMed Central

Mitsiadis, Thimios A.; Graf, Daniel; Luder, Hansueli; Gridley, Thomas; Bluteau, Gilles

2010-01-01

The Notch signalling pathway is an evolutionarily conserved intercellular signalling mechanism that is essential for cell fate specification and proper embryonic development. We have analysed the expression, regulation and function of the jagged 2 (Jag2) gene, which encodes a ligand for the Notch family of receptors, in developing mouse teeth. Jag2 is expressed in epithelial cells that give rise to the enamel-producing ameloblasts from the earliest stages of tooth development. Tissue recombination experiments showed that its expression in epithelium is regulated by mesenchyme-derived signals. In dental explants cultured in vitro, the local application of fibroblast growth factors upregulated Jag2 expression, whereas bone morphogenetic proteins provoked the opposite effect. Mice homozygous for a deletion in the Notch-interaction domain of Jag2 presented a variety of severe dental abnormalities. In molars, the crown morphology was misshapen, with additional cusps being formed. This was due to alterations in the enamel knot, an epithelial signalling structure involved in molar crown morphogenesis, in which Bmp4 expression and apoptosis were altered. In incisors, cytodifferentiation and enamel matrix deposition were inhibited. The expression of Tbx1 in ameloblast progenitors, which is a hallmark for ameloblast differentiation and enamel formation, was dramatically reduced in Jag2−/− teeth. Together, these results demonstrate that Notch signalling mediated by Jag2 is indispensable for normal tooth development. PMID:20685737

Uncontrolled angiogenic precursor expansion causes coronary artery anomalies in mice lacking Pofut1.

PubMed

Wang, Yidong; Wu, Bingruo; Lu, Pengfei; Zhang, Donghong; Wu, Brian; Varshney, Shweta; Del Monte-Nieto, Gonzalo; Zhuang, Zhenwu; Charafeddine, Rabab; Kramer, Adam H; Sibinga, Nicolas E; Frangogiannis, Nikolaos G; Kitsis, Richard N; Adams, Ralf H; Alitalo, Kari; Sharp, David J; Harvey, Richard P; Stanley, Pamela; Zhou, Bin

2017-09-18

Coronary artery anomalies may cause life-threatening cardiac complications; however, developmental mechanisms underpinning coronary artery formation remain ill-defined. Here we identify an angiogenic cell population for coronary artery formation in mice. Regulated by a DLL4/NOTCH1/VEGFA/VEGFR2 signaling axis, these angiogenic cells generate mature coronary arteries. The NOTCH modulator POFUT1 critically regulates this signaling axis. POFUT1 inactivation disrupts signaling events and results in excessive angiogenic cell proliferation and plexus formation, leading to anomalous coronary arteries, myocardial infarction and heart failure. Simultaneous VEGFR2 inactivation fully rescues these defects. These findings show that dysregulated angiogenic precursors link coronary anomalies to ischemic heart disease.Though coronary arteries are crucial for heart function, the mechanisms guiding their formation are largely unknown. Here, Wang et al. identify a unique, endocardially-derived angiogenic precursor cell population for coronary artery formation in mice and show that a DLL4/NOTCH1/VEGFA/VEGFR2 signaling axis is key for coronary artery development.

Cdon acts as a Hedgehog decoy receptor during proximal-distal patterning of the optic vesicle

PubMed Central

Cardozo, Marcos Julián; Sánchez-Arrones, Luisa; Sandonis, África; Sánchez-Camacho, Cristina; Gestri, Gaia; Wilson, Stephen W.; Guerrero, Isabel; Bovolenta, Paola

2014-01-01

Patterning of the vertebrate optic vesicle into proximal/optic stalk and distal/neural retina involves midline-derived Hedgehog (Hh) signalling, which promotes stalk specification. In the absence of Hh signalling, the stalks are not specified, causing cyclopia. Recent studies showed that the cell adhesion molecule Cdon forms a heteromeric complex with the Hh receptor Patched 1 (Ptc1). This receptor complex binds Hh and enhances signalling activation, indicating that Cdon positively regulates the pathway. Here we show that in the developing zebrafish and chick optic vesicle, in which cdon and ptc1 are expressed with a complementary pattern, Cdon acts as a negative Hh signalling regulator. Cdon predominantly localizes to the basolateral side of neuroepithelial cells, promotes the enlargement of the neuroepithelial basal end-foot and traps Hh protein, thereby limiting its dispersion. This Ptc-independent function protects the retinal primordium from Hh activity, defines the stalk/retina boundary and thus the correct proximo-distal patterning of the eye. PMID:25001599

Hemogenic endothelial cell specification requires c-kit, notch signaling, and p27-mediated cell-cycle control

USDA-ARS?s Scientific Manuscript database

Delineating the mechanism or mechanisms that regulate the specification of hemogenic endothelial cells from primordial endothelium is critical for optimizing their derivation from human stem cells for clinical therapies. We previously determined that retinoic acid (RA) is required for hemogenic spec...

UPTAKE AND METABOLISM OF ALL-TRANS RETINOIC ACID BY THREE NATIVE NORTH AMERICAN RANIDS

EPA Science Inventory

Retinoids, which are Vvitamin A derivatives, are important signaling molecules that regulate processes critical for development in all vertebrates. The objective of our study was to examine uptake and metabolism of the model retinoid, all-trans retinoic acid (all-trans RA), by th...

β3-Adrenergic Regulation of EPC Features Through Manipulation of the Bone Marrow MSC Niche.

PubMed

Vafaei, Rana; Nassiri, Seyed Mahdi; Siavashi, Vahid

2017-12-01

Mesenchymal stem cells (MSCs) reside in a specific niche in the bone marrow, however, biological features of this niche are still not fully understood. Given the interactions of MSCs with endothelial cells in different tissues, bone marrow MSC niche may influence the biological features of endothelial progenitor cells (EPCs). To understand the role of the sympathetic nervous system in regulation of the MSC niche, we examined whether the manipulation of the MSC niche via β3-adrenergic signals will affect EPC features. A selective β3 agonist (BRL37344) or a β3 antagonist (SR59230A) was administered in mice for 2 weeks to determine the potential effects of these regimens on the population of CD133 + stem cells in the bone marrow. Then, bone marrow-derived MSCs and EPCs were harvested and expanded from the mice to examine the effect of changes in the MSC niche on EPC features. Improved MSC colony forming potency with increased bone marrow stromal cell-derived factor 1 (SDF-1) (also known as C-X-C motif chemokine 12 [CXCL12]) expression was shown as a result of intensification of the bone marrow adrenergic signals through BRL37344 injection. On the other hand, the blockage of these signals limited the expression level of SDF-1 and resulted in bone marrow enrichment of CD133 + cells. Manipulation of the MSC niche and decreased SDF-1 expression via SR59230A injection also prompted EPCs to form more colonies with augmented proliferation and differentiation capacity. Overall, our results indicate that the β3-adrenergic signals regulate the MSC niche, thereby resulting in modulation of EPC biological features. J. Cell. Biochem. 118: 4753-4761, 2017. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

Circadian control of p75 neurotrophin receptor leads to alternate activation of Nrf2 and c-Rel to reset energy metabolism in astrocytes via brain-derived neurotrophic factor.

PubMed

Ishii, Tetsuro; Warabi, Eiji; Mann, Giovanni E

2018-05-01

Circadian clock genes regulate energy metabolism partly through neurotrophins in the body. The low affinity neurotrophin receptor p75 NTR is a clock component directly regulated by the transcriptional factor Clock:Bmal1 complex. Brain-derived neurotrophic factor (BDNF) is expressed in the brain and plays a key role in coordinating metabolic interactions between neurons and astrocytes. BDNF transduces signals through TrkB and p75 NTR receptors. This review highlights a novel molecular mechanism by which BDNF via circadian control of p75 NTR leads to daily resetting of glucose and glycogen metabolism in brain astrocytes to accommodate their functional interaction with neurons. Astrocytes store glycogen as an energy reservoir to provide active neurons with the glycolytic metabolite lactate. Astrocytes predominantly express the truncated receptor TrkB.T1 which lacks an intracellular receptor tyrosine kinase domain. TrkB.T1 retains the capacity to regulate cell morphology through regulation of Rho GTPases. In contrast, p75 NTR mediates generation of the bioactive lipid ceramide upon stimulation with BDNF and inhibits PKA activation. As ceramide directly activates PKCζ, we discuss the importance of the TrkB.T1-p75 NTR -ceramide-PKCζ signaling axis in the stimulation of glycogen and lipid synthesis and activation of RhoA. Ceramide-PKCζ-casein kinase 2 signaling activates Nrf2 to support oxidative phosphorylation via upregulation of antioxidant enzymes. In the absence of p75 NTR , TrkB.T1 functionally interacts with adenosine A 2A R and dopamine D1R receptors to enhance cAMP-PKA signaling and activate Rac1 and NF-κB c-Rel, favoring glycogen hydrolysis, gluconeogenesis and aerobic glycolysis. Thus, diurnal changes in p75 NTR levels in astrocytes resets energy metabolism via BDNF to accommodate their metabolic interaction with neurons. Copyright © 2018 Elsevier Inc. All rights reserved.

Induction of the plasticity-associated immediate early gene Arc by stress and hallucinogens: role of brain-derived neurotrophic factor.

PubMed

Benekareddy, Madhurima; Nair, Amrita R; Dias, Brian G; Suri, Deepika; Autry, Anita E; Monteggia, Lisa M; Vaidya, Vidita A

2013-03-01

Exposure to stress and hallucinogens in adulthood evokes persistent alterations in neurocircuitry and emotional behaviour. The structural and functional changes induced by stress and hallucinogen exposure are thought to involve transcriptional alterations in specific effector immediate early genes. The immediate early gene, activity regulated cytoskeletal-associated protein (Arc), is important for both activity and experience dependent plasticity. We sought to examine whether trophic factor signalling through brain-derived neurotrophic factor (BDNF) contributes to the neocortical regulation of Arc mRNA in response to distinct stimuli such as immobilization stress and the hallucinogen 2,5-dimethoxy-4-iodoamphetamine (DOI). Acute exposure to either immobilization stress or DOI induced Arc mRNA levels within the neocortex. BDNF infusion into the neocortex led to a robust up-regulation of local Arc transcript expression. Further, baseline Arc mRNA expression in the neocortex was significantly decreased in inducible BDNF knockout mice with an adult-onset, forebrain specific BDNF loss. The induction of Arc mRNA levels in response to both acute immobilization stress or a single administration of DOI was significantly attenuated in the inducible BDNF knockout mice. Taken together, our results implicate trophic factor signalling through BDNF in the regulation of cortical Arc mRNA expression, both under baseline conditions and following stress and hallucinogen exposure. These findings suggest the possibility that the regulation of Arc expression via BDNF provides a molecular substrate for the structural and synaptic plasticity observed following stimuli such as stress and hallucinogens.

Transcriptome-Wide Identification of RNA Targets of Arabidopsis SERINE/ARGININE-RICH45 Uncovers the Unexpected Roles of This RNA Binding Protein in RNA Processing[OPEN

PubMed Central

Wang, Yajun; Hamilton, Michael; Ben-Hur, Asa; Reddy, Anireddy S.N.

2015-01-01

Plant SR45 and its metazoan ortholog RNPS1 are serine/arginine-rich (SR)-like RNA binding proteins that function in splicing/postsplicing events and regulate diverse processes in eukaryotes. Interactions of SR45 with both RNAs and proteins are crucial for regulating RNA processing. However, in vivo RNA targets of SR45 are currently unclear. Using RNA immunoprecipitation followed by high-throughput sequencing, we identified over 4000 Arabidopsis thaliana RNAs that directly or indirectly associate with SR45, designated as SR45-associated RNAs (SARs). Comprehensive analyses of these SARs revealed several roles for SR45. First, SR45 associates with and regulates the expression of 30% of abscisic acid (ABA) signaling genes at the postsplicing level. Second, although most SARs are derived from intron-containing genes, surprisingly, 340 SARs are derived from intronless genes. Expression analysis of the SARs suggests that SR45 differentially regulates intronless and intron-containing SARs. Finally, we identified four overrepresented RNA motifs in SARs that likely mediate SR45’s recognition of its targets. Therefore, SR45 plays an unexpected role in mRNA processing of intronless genes, and numerous ABA signaling genes are targeted for regulation at the posttranscriptional level. The diverse molecular functions of SR45 uncovered in this study are likely applicable to other species in view of its conservation across eukaryotes. PMID:26603559

Immunomodulatory Activities of the Benzoxathiole Derivative BOT-4-One Ameliorate Pathogenic Skin Inflammation in Mice.

PubMed

Lee, Hyun Gyu; Cho, Nam-Chul; Jeong, Ae Jin; Li, Yu-Chen; Rhie, Sung-Ja; Choi, Jung Sook; Lee, Kwang-Ho; Kim, Youngsoo; Kim, Yong-Nyun; Kim, Myoung-Hwan; Pae, Ae Nim; Ye, Sang-Kyu; Kim, Byung-Hak

2015-09-30

T cell-mediated immune responses play an important role in body protection. However, aberrantly activated immune responses are responsible for inflammatory and autoimmune diseases. The regulation of pathological immune responses may be a potential therapeutic strategy for the treatment of these diseases. Despite multiple pharmacological properties of benzoxathiole derivatives have been defined, the molecular mechanisms underlying these properties remain to be clarified. Here, we demonstrated the benzoxathiole derivative 2-cyclohexylimino-6-methyl-6,7-dihydro-5H-benzo[1,3]oxathiol-4-one (BOT-4-one) regulated immune responses and ameliorated experimentally induced inflammatory skin diseases both in vitro and in vivo. BOT-4-one inhibited the differentiation of CD4 + T-cell subsets by regulating the expression and production of T cell lineage-specific master transcription factors and cytokines and activating the signal transducer and activator of transcription (STAT) proteins. In addition, BOT-4-one inhibited T-cell receptor (TCR)-mediated Akt and nuclear factor-kappaB (NF-κB) signaling. Topical application of BOT-4-one ameliorated experimentally induced inflammatory skin diseases in mice models such as TNCB-induced contact and atopic dermatitis and IL-23-induced psoriasis-like skin inflammation. Our study demonstrated that BOT-4-one ameliorates inflammatory skin diseases by suppressing the pathogenic CD4 + T cell differentiation and the overall immune responses.Journal of Investigative Dermatology accepted article preview online, 30 September 2015. doi:10.1038/jid.2015.384.

A diffusible signal derived from hematopoietic cells supports the survival and proliferation of regenerative cells during zebrafish fin fold regeneration.

PubMed

Hasegawa, Tomoya; Nakajima, Teruhiro; Ishida, Takashi; Kudo, Akira; Kawakami, Atsushi

2015-03-01

Multicellular organisms maintain body integrity by constantly regenerating tissues throughout their lives; however, the overall mechanism for regulating regeneration remains an open question. Studies of limb and fin regeneration in teleost fish and urodeles have shown the involvement of a number of locally activated signals at the wounded site during regeneration. Here, we demonstrate that a diffusible signal from a distance also play an essential role for regeneration. Among a number of zebrafish mutants, we found that the zebrafish cloche (clo) and tal1 mutants, which lack most hematopoietic tissues, displayed a unique regeneration defect accompanying apoptosis in primed regenerative tissue. Our analyses of the mutants showed that the cells in the primed regenerative tissue are susceptible to apoptosis, but their survival is normally supported by the presence of hematopoietic tissues, mainly the myeloid cells. We further showed that a diffusible factor in the wild-type body fluid mediates this signal. Thus, our study revealed a novel mechanism that the hematopoietic tissues regulate tissue regeneration through a diffusible signal. Copyright © 2014 Elsevier Inc. All rights reserved.

Sonic hedgehog signaling in kidney fibrosis: a master communicator.

PubMed

Zhou, Dong; Tan, Roderick J; Liu, Youhua

2016-09-01

The hedgehog signaling cascade is an evolutionarily conserved pathway that regulates multiple aspects of embryonic development and plays a decisive role in tissue homeostasis. As the best studied member of three hedgehog ligands, sonic hedgehog (Shh) is known to be associated with kidney development and tissue repair after various insults. Recent studies uncover an intrinsic link between dysregulated Shh signaling and renal fibrogenesis. In various types of chronic kidney disease (CKD), Shh is upregulated specifically in renal tubular epithelium but targets interstitial fibroblasts, thereby mediating a dynamic epithelial- mesenchymal communication (EMC). Tubule-derived Shh acts as a growth factor for interstitial fibroblasts and controls a hierarchy of fibrosis-related genes, which lead to the excessive deposition of extracellular matrix in renal interstitium. In this review, we recapitulate the principle of Shh signaling, its activation and regulation in a variety of kidney diseases. We also discuss the potential mechanisms by which Shh promotes renal fibrosis and assess the efficacy of blocking this signaling in preclinical settings. Continuing these lines of investigations will provide novel opportunities for designing effective therapies to improve CKD prognosis in patients.

Sonic hedgehog signaling in kidney fibrosis: a master communicator

PubMed Central

Zhou, Dong; Tan, Roderick J.; Liu, Youhua

2017-01-01

The hedgehog signaling cascade is an evolutionarily conserved pathway that regulates multiple aspects of embryonic development and plays a decisive role in tissue homeostasis. As the best studied member of three hedgehog ligands, sonic hedgehog (Shh) is known to be associated with kidney development and tissue repair after various insults. Recent studies uncover an intrinsic link between dysregulated Shh signaling and renal fibrogenesis. In various types of chronic kidney disease (CKD), Shh is upregulated specifically in renal tubular epithelium but targets interstitial fibroblasts, thereby mediating a dynamic epithelial-mesenchymal communication (EMC). Tubule-derived Shh acts as a growth factor for interstitial fibroblasts and controls a hierarchy of fibrosis-related genes, which lead to the excessive deposition of extracellular matrix in renal interstitium. In this review, we recapitulate the principle of Shh signaling, its activation and regulation in a variety of kidney diseases. We also discuss the potential mechanisms by which Shh promotes renal fibrosis and assess the efficacy of blocking this signaling in preclinical settings. Continuing these lines of investigations will provide novel opportunities for designing effective therapies to improve CKD prognosis in patients. PMID:27333788

Androgen Receptor Roles in Insulin Resistance and Obesity in Males: The Linkage of Androgen-Deprivation Therapy to Metabolic Syndrome

PubMed Central

Yu, I-Chen; Lin, Hung-Yun; Sparks, Janet D.; Yeh, Shuyuan

2014-01-01

Prostate cancer (PCa) is one of the most frequently diagnosed malignancies in men. Androgen-deprivation therapy (ADT) is the first-line treatment and fundamental management for men with advanced PCa to suppress functions of androgen/androgen receptor (AR) signaling. ADT is effective at improving cancer symptoms and prolonging survival. However, epidemiological and clinical studies support the notion that testosterone deficiency in men leads to the development of metabolic syndrome that increases cardiovascular disease risk. The underlying mechanisms by which androgen/AR signaling regulates metabolic homeostasis in men are complex, and in this review, we discuss molecular mechanisms mediated by AR signaling that link ADT to metabolic syndrome. Results derived from various AR knockout mouse models reveal tissue-specific AR signaling that is involved in regulation of metabolism. These data suggest that steps be taken early to manage metabolic complications associated with PCa patients receiving ADT, which could be accomplished using tissue-selective modulation of AR signaling and by treatment with insulin-sensitizing agents. PMID:25249645

UAP56 is an important mediator of Angiotensin II/platelet derived growth factor induced vascular smooth muscle cell DNA synthesis and proliferation

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

Sahni, Abha; Department of Pathology, University of Texas Medical Branch, Galveston, TX 77555; Wang, Nadan

2013-02-15

Highlights: ► Knockdown of UAP56 inhibits Angiotensin II/PDGF induced vascular smooth muscle cell proliferation. ► UAP56 is a positive regulator of E2F transcriptional activation. ► UAP56 is present in the vessel wall of low flow carotid arteries. -- Abstract: Angiotensin (Ang) II and platelet-derived growth factor (PDGF) are important mediators of pathologic vascular smooth muscle cell (VSMC) proliferation. Identifying downstream mediators of Ang II and PDGF signaling may provide insights for therapies to improve vascular proliferative diseases. We have previously demonstrated that breakpoint cluster region (Bcr) is an important mediator of Ang II/PDGF signaling in VSMC. We have recently reportedmore » that the DExD/H box protein UAP56 is an interacting partner of Bcr in regulating VSMC DNA synthesis. We hypothesized that UAP56 itself is an important regulator of VSMC proliferation. In this report we demonstrate that knockdown of UAP56 inhibits Ang II/PDGF induced VSMC DNA synthesis and proliferation, and inhibits E2F transcriptional activity. In addition, we demonstrate that UAP56 is present in the vessel wall of low-flow carotid arteries. These findings suggest that UAP56 is a regulator of VSMC proliferation and identify UAP56 as a target for preventing vascular proliferative disease.« less

Transgenic studies reveal the positive role of LeEIL-1 in regulating shikonin biosynthesis in Lithospermum erythrorhizon hairy roots.

PubMed

Fang, Rongjun; Zou, Ailan; Zhao, Hua; Wu, Fengyao; Zhu, Yu; Zhao, Hu; Liao, Yonghui; Tang, Ren-Jie; Pang, Yanjun; Yang, Rongwu; Wang, Xiaoming; Qi, Jinliang; Lu, Guihua; Yang, Yonghua

2016-05-26

The phytohormone ethylene (ET) is a key signaling molecule for inducing the biosynthesis of shikonin and its derivatives, which are secondary metabolites in Lithospermum erythrorhizon. Although ETHYLENE INSENSITIVE3 (EIN3)/EIN3-like proteins (EILs) are crucial transcription factors in ET signal transduction pathway, the possible function of EIN3/EIL1 in shikonin biosynthesis remains unknown. In this study, by targeting LeEIL-1 (L. erythrorhizon EIN3-like protein gene 1) at the expression level, we revealed the positive regulatory effect of LeEIL-1 on shikonin formation. The mRNA level of LeEIL-1 was significantly up-regulated and down-regulated in the LeEIL-1-overexpressing hairy root lines and LeEIL-1-RNAi hairy root lines, respectively. Specifically, LeEIL-1 overexpression resulted in increased transcript levels of the downstream gene of ET signal transduction pathway (LeERF-1) and a subset of genes for shikonin formation, excretion and/or transportation (LePAL, LeC4H-2, Le4CL-1, HMGR, LePGT-1, LeDI-2, and LePS-2), which was consistent with the enhanced shikonin contents in the LeEIL-1-overexpressing hairy root lines. Conversely, LeEIL-1-RNAi dramatically repressed the expression of the above genes and significantly reduced shikonin production. The results revealed that LeEIL-1 is a positive regulator of the biosynthesis of shikonin and its derivatives in L. erythrorhizon hairy roots. Our findings gave new insights into the molecular regulatory mechanism of ET in shikonin biosynthesis. LeEIL-1 could be a crucial target gene for the genetic engineering of shikonin biosynthesis.

Particulate matter triggers depressive-like response associated with modulation of inflammatory cytokine homeostasis and brain-derived neurotrophic factor signaling pathway in mice.

PubMed

Liu, Xuemei; Qian, Xin; Xing, Jing; Wang, Jinhua; Sun, Yixuan; Wang, Qin'geng; Li, Huiming

2018-04-23

Particulate matter (PM) exposure may contribute to depressive-like response in mice. However, few studies have evaluated the adaptive impacts of long-term PM exposure on depressive-like response associated with systemic inflammation and brain-derived neurotrophic factor (BDNF) signaling pathway. We studied the association among depressive-like behaviors, mRNA levels of pro- and anti-inflammatory cytokines, and the expression of BDNF signaling pathway in mice by long-term PM exposure. C57BL/6 male mice were exposed to ambient air alongside control mice breathing air filtered through a high-efficiency air PM (HEPA) filter. Depressive-like behaviors were assessed together with pro-inflammatory, anti-inflammatory cytokine mRNA levels and the modulation of BDNF pathway in hippocampus and olfactory-bulb of mice exposed to PM for 4, 8, and 12 weeks. Exposure to HEPA filtered air for 4 weeks may exert antidepressant like effects in mice. Pro-inflammatory cytokines were up-regulated while the expression of BDNF, its high-affinity receptor tropomyosin-related kinase B (TrkB), and the transcription factor cAMP-response-element binding protein (CREB) were down-regulated in ambient air mice. However, after 8 weeks, there was no significant difference in the rate of depressive-like behaviors between the two groups. After 12 weeks, mice exposed to ambient air again had a higher rate of depressive-like behaviors, significant up-regulation of pro-inflammatory cytokines, down-regulation of interleukin-10 (IL-10), BDNF, TrkB, and CREB than HEPA mice. Ultrafine PM in brain tissues of mice exposed to ambient air was observed. Our results suggest continuous high-level PM exposure alters the depressive-like response in mice and induces a damage-repair-imbalance reaction.

Ubiquitin C-Terminal Hydrolase L1 (UCH-L1) Promotes Hippocampus-Dependent Memory via Its Deubiquitinating Effect on TrkB.

PubMed

Guo, Yun-Yun; Lu, Yi; Zheng, Yuan; Chen, Xiao-Rong; Dong, Jun-Lu; Yuan, Rong-Rong; Huang, Shu-Hong; Yu, Hui; Wang, Yue; Chen, Zhe-Yu; Su, Bo

2017-06-21

Multiple studies have established that brain-derived neurotrophic factor (BDNF) plays a critical role in the regulation of synaptic plasticity via its receptor, TrkB. In addition to being phosphorylated, TrkB has also been demonstrated to be ubiquitinated. However, the mechanisms of TrkB ubiquitination and its biological functions remain poorly understood. In this study, we demonstrate that ubiquitin C-terminal hydrolase L1 (UCH-L1) promotes contextual fear conditioning learning and memory via the regulation of ubiquitination of TrkB. We provide evidence that UCH-L1 can deubiquitinate TrkB directly. K460 in the juxtamembane domain of TrkB is the primary ubiquitination site and is regulated by UCH-L1. By using a peptide that competitively inhibits the association between UCH-L1 and TrkB, we show that the blockade of UCH-L1-regulated TrkB deubiquitination leads to increased BDNF-induced TrkB internalization and consequently directs the internalized TrkB to the degradation pathway, resulting in increased degradation of surface TrkB and attenuation of TrkB activation and its downstream signaling pathways. Moreover, injection of the peptide into the DG region of mice impairs hippocampus-dependent memory. Together, our results suggest that the ubiquitination of TrkB is a mechanism that controls its downstream signaling pathways via the regulation of its endocytosis and postendocytic trafficking and that UCH-L1 mediates the deubiquitination of TrkB and could be a potential target for the modulation of hippocampus-dependent memory. SIGNIFICANCE STATEMENT Ubiquitin C-terminal hydrolase L1 (UCH-L1) has been demonstrated to play important roles in the regulation of synaptic plasticity and learning and memory. TrkB, the receptor for brain-derived neurotrophic factor, has also been shown to be a potent regulator of synaptic plasticity. In this study, we demonstrate that UCH-L1 functions as a deubiquitinase for TrkB. The blockage of UCH-L1-regulated deubiquitination of TrkB eventually results in the increased degradation of surface TrkB and decreased activation of TrkB and its downstream signaling pathways. In vivo , UCH-L1-regulated TrkB deubiquitination is necessary for hippocampus-dependent memory. Overall, our study provides novel insights into the mechanisms of UCH-L1-mediated neurobiological functions and suggests that ubiquitination is an important regulatory signal for TrkB functions. Copyright © 2017 the authors 0270-6474/17/375978-18$15.00/0.

Aiding and abetting roles of NOX oxidases in cellular transformation

PubMed Central

Block, Karen; Gorin, Yves

2013-01-01

NADPH oxidases of the NADPH oxidase (NOX) family are dedicated reactive oxygen species-generating enzymes that broadly and specifically regulate redox-sensitive signalling pathways that are involved in cancer development and progression. They act at specific cellular membranes and microdomains through the activation of oncogenes and the inactivation of tumour suppressor proteins. In this Review, we discuss primary targets and redox-linked signalling systems that are influenced by NOX-derived ROS, and the biological role of NOX oxidases in the aetiology of cancer. PMID:22918415

Self-regulating proportionally controlled heating apparatus and technique

NASA Technical Reports Server (NTRS)

Strange, M. G. (Inventor)

1975-01-01

A self-regulating proportionally controlled heating apparatus and technique is provided wherein a single electrical resistance heating element having a temperature coefficient of resistance serves simultaneously as a heater and temperature sensor. The heating element is current-driven and the voltage drop across the heating element is monitored and a component extracted which is attributable to a change in actual temperature of the heating element from a desired reference temperature, so as to produce a resulting error signal. The error signal is utilized to control the level of the heater drive current and the actual heater temperature in a direction to reduce the noted temperature difference. The continuous nature of the process for deriving the error signal feedback information results in true proportional control of the heating element without the necessity for current-switching which may interfere with nearby sensitive circuits, and with no cyclical variation in the controlled temperature.

Peptides interfering with protein-protein interactions in the ethylene signaling pathway delay tomato fruit ripening

NASA Astrophysics Data System (ADS)

Bisson, Melanie M. A.; Kessenbrock, Mareike; Müller, Lena; Hofmann, Alexander; Schmitz, Florian; Cristescu, Simona M.; Groth, Georg

2016-08-01

The plant hormone ethylene is involved in the regulation of several processes with high importance for agricultural applications, e.g. ripening, aging and senescence. Previous work in our group has identified a small peptide (NOP-1) derived from the nuclear localization signal of the Arabidopsis ethylene regulator ETHYLENE INSENSITIVE-2 (EIN2) C-terminal part as efficient inhibitor of ethylene responses. Here, we show that NOP-1 is also able to efficiently disrupt EIN2-ETR1 complex formation in tomato, indicating that the NOP-1 inhibition mode is conserved across plant species. Surface application of NOP-1 on green tomato fruits delays ripening similar to known inhibitors of ethylene perception (MCP) and ethylene biosynthesis (AVG). Fruits treated with NOP-1 showed similar ethylene production as untreated controls underlining that NOP-1 blocks ethylene signaling by targeting an essential interaction in this pathway, while having no effect on ethylene biosynthesis.

Peptides interfering with protein-protein interactions in the ethylene signaling pathway delay tomato fruit ripening.

PubMed

Bisson, Melanie M A; Kessenbrock, Mareike; Müller, Lena; Hofmann, Alexander; Schmitz, Florian; Cristescu, Simona M; Groth, Georg

2016-08-01

The plant hormone ethylene is involved in the regulation of several processes with high importance for agricultural applications, e.g. ripening, aging and senescence. Previous work in our group has identified a small peptide (NOP-1) derived from the nuclear localization signal of the Arabidopsis ethylene regulator ETHYLENE INSENSITIVE-2 (EIN2) C-terminal part as efficient inhibitor of ethylene responses. Here, we show that NOP-1 is also able to efficiently disrupt EIN2-ETR1 complex formation in tomato, indicating that the NOP-1 inhibition mode is conserved across plant species. Surface application of NOP-1 on green tomato fruits delays ripening similar to known inhibitors of ethylene perception (MCP) and ethylene biosynthesis (AVG). Fruits treated with NOP-1 showed similar ethylene production as untreated controls underlining that NOP-1 blocks ethylene signaling by targeting an essential interaction in this pathway, while having no effect on ethylene biosynthesis.

The Role of Target of Rapamycin Signaling Networks in Plant Growth and Metabolism1

PubMed Central

Sheen, Jen

2014-01-01

The target of rapamycin (TOR) kinase, a master regulator that is evolutionarily conserved among yeasts (Saccharomyces cerevisiae), plants, animals, and humans, integrates nutrient and energy signaling to promote cell proliferation and growth. Recent breakthroughs made possible by integrating chemical, genetic, and genomic analyses have greatly increased our understanding of the molecular functions and dynamic regulation of the TOR kinase in photosynthetic plants. TOR signaling plays fundamental roles in embryogenesis, meristem activation, root and leaf growth, flowering, senescence, and life span determination. The molecular mechanisms underlying TOR-mediated ribosomal biogenesis, translation promotion, readjustment of metabolism, and autophagy inhibition are now being uncovered. Moreover, monitoring photosynthesis-derived Glc and bioenergetics relays has revealed that TOR orchestrates unprecedented transcriptional networks that wire central metabolism and biosynthesis for energy and biomass production. In addition, these networks integrate localized stem/progenitor cell proliferation through interorgan nutrient coordination to control developmental transitions and growth. PMID:24385567

Age-related increase in Wnt inhibitor causes a senescence-like phenotype in human cardiac stem cells

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

Nakamura, Tamami; Hosoyama, Tohru; Regenerative Medicine Institute, Yamaguchi University Graduate School of Medicine

Aging of cardiac stem/progenitor cells (CSCs) impairs heart regeneration and leads to unsatisfactory outcomes of cell-based therapies. As the precise mechanisms underlying CSC aging remain unclear, the use of therapeutic strategies for elderly patients with heart failure is severely delayed. In this study, we used human cardiosphere-derived cells (CDCs), a subtype of CSC found in the postnatal heart, to identify secreted factor(s) associated with CSC aging. Human CDCs were isolated from heart failure patients of various ages (2–83 years old). Gene expression of key soluble factors was compared between CDCs derived from young and elderly patients. Among these factors, SFRP1,more » a gene encoding a Wnt antagonist, was significantly up-regulated in CDCs from elderly patients (≥65 years old). sFRP1 levels was increased significantly also in CDCs, whose senescent phenotype was induced by anti-cancer drug treatment. These results suggest the participation of sFRP1 in CSC aging. We show that the administration of recombinant sFRP1 induced cellular senescence in CDCs derived from young patients, as indicated by increased levels of markers such as p16, and a senescence-associated secretory phenotype. In addition, co-administration of recombinant sFRP1 could abrogate the accelerated CDC proliferation induced by Wnt3A. Taken together, our results suggest that canonical Wnt signaling and its antagonist, sFRP1, regulate proliferation of human CSCs. Furthermore, excess sFRP1 in elderly patients causes CSC aging. - Highlights: • Wnt signaling regulates proliferation of human cardiac stem cells. • Expression of sFRP1, which is a Wnt antagonist, is up-regulated in elderly patients with heart failure. • Expression of sFRP1 is increased in anti-cancer drug-induced senescent human cardiac stem cells. • sFRP1 causes cellular senescence of young patients-derived cardiac stem cells.« less

Oleic Acid–Dependent Modulation of NITRIC OXIDE ASSOCIATED1 Protein Levels Regulates Nitric Oxide–Mediated Defense Signaling in Arabidopsis[C][W

PubMed Central

Mandal, Mihir Kumar; Chandra-Shekara, A.C.; Jeong, Rae-Dong; Yu, Keshun; Zhu, Shifeng; Chanda, Bidisha; Navarre, Duroy; Kachroo, Aardra; Kachroo, Pradeep

2012-01-01

The conserved cellular metabolites nitric oxide (NO) and oleic acid (18:1) are well-known regulators of disease physiologies in diverse organism. We show that NO production in plants is regulated via 18:1. Reduction in 18:1 levels, via a genetic mutation in the 18:1-synthesizing gene SUPPRESSOR OF SA INSENSITIVITY OF npr1-5 (SSI2) or exogenous application of glycerol, induced NO accumulation. Furthermore, both NO application and reduction in 18:1 induced the expression of similar sets of nuclear genes. The altered defense signaling in the ssi2 mutant was partially restored by a mutation in NITRIC OXIDE ASSOCIATED1 (NOA1) and completely restored by double mutations in NOA1 and either of the nitrate reductases. Biochemical studies showed that 18:1 physically bound NOA1, in turn leading to its degradation in a protease-dependent manner. In concurrence, overexpression of NOA1 did not promote NO-derived defense signaling in wild-type plants unless 18:1 levels were lowered. Subcellular localization showed that NOA1 and the 18:1 synthesizing SSI2 proteins were present in close proximity within the nucleoids of chloroplasts. Indeed, pathogen-induced or low-18:1-induced accumulation of NO was primarily detected in the chloroplasts and their nucleoids. Together, these data suggest that 18:1 levels regulate NO synthesis, and, thereby, NO-mediated signaling, by regulating NOA1 levels. PMID:22492810

The small molecule '1-(4-biphenylylcarbonyl)-4-(5-bromo-2-methoxybenzyl) piperazine oxalate' and its derivatives regulate global protein synthesis by inactivating eukaryotic translation initiation factor 2-alpha.

PubMed

Hong, Mi-Na; Nam, Ky-Youb; Kim, Kyung Kon; Kim, So-Young; Kim, InKi

2016-05-01

By environmental stresses, cells can initiate a signaling pathway in which eukaryotic translation initiation factor 2-alpha (eIF2-α) is involved to regulate the response. Phosphorylation of eIF2-α results in the reduction of overall protein neogenesis, which allows cells to conserve resources and to reprogram energy usage for effective stress control. To investigate the role of eIF2-α in cell stress responses, we conducted a viability-based compound screen under endoplasmic reticulum (ER) stress condition, and identified 1-(4-biphenylylcarbonyl)-4-(5-bromo-2-methoxybenzyl) piperazine oxalate (AMC-01) and its derivatives as eIF2-α-inactivating chemical. Molecular characterization of this signaling pathway revealed that AMC-01 induced inactivation of eIF2-α by phosphorylating serine residue 51 in a dose- and time-dependent manner, while the negative control compounds did not affect eIF2-α phosphorylation. In contrast with ER stress induction by thapsigargin, phosphorylation of eIF2-α persisted for the duration of incubation with AMC-01. By pathway analysis, AMC-01 clearly induced the activation of protein kinase RNA-activated (PKR) kinase and nuclear factor-κB (NF-κB), whereas it did not modulate the activity of PERK or heme-regulated inhibitor (HRI). Finally, we could detect a lower protein translation rate in cells incubated with AMC-01, establishing AMC-01 as a potent chemical probe that can regulate eIF2-α activity. We suggest from these data that AMC-01 and its derivative compounds can be used as chemical probes in future studies of the role of eIF2-α in protein synthesis-related cell physiology.

Interferon-Gamma and Fas Are Involved in Porphyromonas gingivalis-Induced Apoptosis of Human Extravillous Trophoblast-Derived HTR8/SVneo Cells via Extracellular Signal-Regulated Kinase 1/2 Pathway.

PubMed

Ren, Hongyu; Li, Yuhong; Jiang, Han; Du, Minquan

2016-11-01

A number of studies recently revealed a link between periodontal disease and preterm birth (PTB). PTB can be induced by dental infection with Porphyromonas gingivalis (Pg), a periodontopathic bacterium. This study aims to investigate responses of human extravillous trophoblast-derived HTR8/SVneo cells to Pg infection. Cell apoptosis, cell viability, protein expression, and cytokine production in HTR8 cells were measured via: 1) flow cytometry, 2) CCK-8 assay, 3) western blot, and 4) enzyme-linked immunosorbent assay methods, respectively. Pg decreased cell viability and increased cell apoptosis, active caspase-3 and Fas expression, and interferon-gamma (IFN-γ) secretion in HTR8 cells. Extracellular signal-regulated kinase (ERK) 1/2 inhibitor U0126 and FasL neutralizing antibody NOK1 that blocks FasL/Fas interaction both significantly suppressed Pg-induced apoptosis. U0126 also inhibited IFN-γ secretion and Fas expression close to control levels. Moreover, treatment with recombinant IFN-γ also significantly decreased number of viable HTR8 cells and increased Fas expression, suggesting IFN-γ may play an important role in Pg-induced apoptosis of HTR8 cells, at least partially through regulation of Fas expression. To the best of the authors' knowledge, this is the first study to demonstrate Pg induces IFN-γ secretion, Fas expression, and apoptosis in human extravillous trophoblast-derived HTR8/SVneo cells in an ERK1/2-dependent manner, and IFN-γ (explored by recombinant IFN-γ) and Fas are involved in Pg-induced apoptosis. The finding that Pg infection abnormally regulates inflammation and apoptosis of human trophoblasts may give new insights into the possible link of PTB with maternal periodontal disease and periodontal pathogens.

Measurement of Epidermal Growth Factor Receptor-Derived Signals Within Plasma Membrane Clathrin Structures.

PubMed

Lucarelli, Stefanie; Delos Santos, Ralph Christian; Antonescu, Costin N

2017-01-01

The epidermal growth factor (EGF) receptor (EGFR) is an important regulator of cell growth, proliferation, survival, migration, and metabolism. EGF binding to EGFR triggers the activation of the receptor's intrinsic kinase activity, in turn eliciting the recruitment of many secondary signaling proteins and activation of downstream signals, such as the activation of phosphatidylinositol-3-kinase (PI3K) and Akt, a process requiring the phosphorylation of Gab1. While the identity of many signals that can be activated by EGFR has been revealed, how the spatiotemporal organization of EGFR signaling within cells controls receptor outcome remains poorly understood. Upon EGF binding at the plasma membrane, EGFR is internalized by clathrin-mediated endocytosis following recruitment to clathrin-coated pits (CCPs). Further, plasma membrane CCPs, but not EGFR internalization, are required for EGF-stimulated Akt phosphorylation. Signaling intermediates such as phosphorylated Gab1, which lead to Akt phosphorylation, are enriched within CCPs upon EGF stimulation. These findings indicate that some plasma membrane CCPs also serve as signaling microdomains required for certain facets of EGFR signaling and are enriched in key EGFR signaling intermediates. Understanding how the spatiotemporal organization of EGFR signals within CCP microdomains controls receptor signaling outcome requires imaging methods that can systematically resolve and analyze the properties of CCPs, EGFR and key signaling intermediates. Here, we describe methods using total internal reflection fluorescence microscopy imaging and analysis to systematically study the enrichment of EGFR and key EGFR-derived signals within CCPs.

Maternal obesity alters brain derived neurotrophic factor (BDNF) signaling in the placenta in a sexually dimorphic manner.

PubMed

Prince, Calais S; Maloyan, Alina; Myatt, Leslie

2017-01-01

Obesity is a major clinical problem in obstetrics being associated with adverse pregnancy outcomes and fetal programming. Brain derived neurotrophic factor (BDNF), a validated miR-210 target, is necessary for placental development, fetal growth, glucose metabolism, and energy homeostasis. Plasma BDNF levels are reduced in obese individuals; however, placental BDNF has yet to be studied in the context of maternal obesity. In this study, we investigated the effect of maternal obesity and sexual dimorphism on placental BDNF signaling. BDNF signaling was measured in placentas from lean (pre-pregnancy BMI < 25) and obese (pre-pregnancy BMI>30) women at term without medical complications that delivered via cesarean section without labor. MiRNA-210, BDNF mRNA, proBDNF, and mature BDNF were measured by RT - PCR, ELISA, and Western blot. Downstream signaling via TRKB (BDNF receptor) was measured using Western blot. Maternal obesity was associated with increased miRNA-210 and decreased BDNF mRNA in placentas from female fetuses, and decreased proBDNF in placentas from male fetuses. We also identified decreased mature BDNF in placentas from male fetuses when compared to female fetuses. Mir-210 expression was negatively correlated with mature BDNF protein. TRKB phosphorylated at tyrosine 817, not tyrosine 515, was increased in placentas from obese women. Maternal obesity was associated with increased phosphorylation of MAPK p38 in placentas from male fetuses, but not phosphorylation of ERK p42/44. BDNF regulation is complex and highly regulated. Pre-pregnancy/early maternal obesity adversely affects BDNF/TRKB signaling in the placenta in a sexually dimorphic manner. These data collectively suggest that induction of placental TRKB signaling could ameliorate the placental OB phenotype, thus improving perinatal outcome. Copyright © 2016 Elsevier Ltd. All rights reserved.

EGF stimulates Mg{sup 2+} influx in mammary epithelial cells

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

Trapani, Valentina; Arduini, Daniela; Luongo, Francesca

2014-11-28

Highlights: • EGF stimulation potentiates Mg{sup 2+} influx into epithelial cells. • EGF-induced Mg{sup 2+} influx does not depend on the concomitantly induced Ca{sup 2+} signal. • EGF-induced Ca{sup 2+} signal is dependent on the presence of extracellular Mg{sup 2+}. • New players in EGF-mediated signaling might be exploited as therapeutic targets. - Abstract: Magnesium is well established as a fundamental factor that regulates cell proliferation. However, the molecular mechanisms linking mitogenic signals, extracellular magnesium availability and intracellular effectors are still largely unknown. In the present study we sought to determine whether EGF regulates magnesium homeostasis in normal HC11 mammarymore » epithelial cells. To this end, we measured Mg{sup 2+} and Ca{sup 2+} fluxes by confocal imaging in live cells loaded with specific fluorescent ion indicators (Mag-Fluo-4 and Fluo-4, respectively). EGF stimulation induces a rapid and sustained increase in intracellular Mg{sup 2+}, concomitantly with a rise in intracellular calcium. The increase in intracellular Mg{sup 2+} derives from an influx from the extracellular compartment, and does not depend on Ca{sup 2+}. On the contrary, the increase in intracellular Ca{sup 2+} derives from intracellular stores, and is impaired in the absence of extracellular magnesium. Inhibition of the EGF receptor tyrosine kinase by Tyrphostin AG1478 markedly inhibits EGF-induced Mg{sup 2+} and Ca{sup 2+} signals. These findings demonstrate that not only does Mg{sup 2+} influx represent an important step in the physiological response of epithelial cells to EGF, but unexpectedly the EGF-induced Mg{sup 2+} influx is essential for the Ca{sup 2+} signal to occur.« less

Reduced adiponectin expression after high-fat diet is associated with selective up-regulation of ALDH1A1 and further retinoic acid receptor signaling in adipose tissue

PubMed Central

Landrier, Jean-Francois; Kasiri, Elnaz; Karkeni, Esma; Mihály, Johanna; Béke, Gabriella; Weiss, Kathrin; Lucas, Renata; Aydemir, Gamze; Salles, Jérome; Walrand, Stéphane; de Lera, Angel R.; Rühl, Ralph

2017-01-01

Adiponectin is an adipocyte-derived adipokine with potent antidiabetic, anti-inflammatory, and antiatherogenic activity. Long-term, high-fat diet results in gain of body weight, adiposity, further inflammatory-based cardiovascular diseases, and reduced adiponectin secretion. Vitamin A derivatives/retinoids are involved in several of these processes, which mainly take place in white adipose tissue (WAT). In this study, we examined adiponectin expression as a function of dietary high-fat and high–vitamin A conditions in mice. A decrease of adiponectin expression in addition to an up-regulation of aldehyde dehydrogenase A1 (ALDH1A1), retinoid signaling, and retinoic acid response element signaling was selectively observed in WAT of mice fed a normal–vitamin A, high-fat diet. Reduced adiponectin expression in WAT was also observed in mice fed a high–vitamin A diet. Adipocyte cell culture revealed that endogenous and synthetic retinoic acid receptor (RAR)α- and RARγ-selective agonists, as well as a synthetic retinoid X receptor agonist, efficiently reduced adiponectin expression, whereas ALDH1A1 expression only increased with RAR agonists. We conclude that reduced adiponectin expression under high-fat dietary conditions is dependent on 1) increased ALDH1A1 expression in adipocytes, which does not increase all-trans-retinoic acid levels; 2) further RAR ligand–induced, WAT-selective, increased retinoic acid response element–mediated signaling; and 3) RAR ligand–dependent reduction of adiponectin expression.—Landrier, J.-F., Kasiri, E., Karkeni, E., Mihály, J., Béke, G., Weiss, K., Lucas, R., Aydemir, G., Salles, J., Walrand, S., de Lera, A. R., Rühl, R. Reduced adiponectin expression after high-fat diet is associated with selective up-regulation of ALDH1A1 and further retinoic acid receptor signaling in adipose tissue. PMID:27729412

Excitation-transcription coupling via calcium/calmodulin-dependent protein kinase/ERK1/2 signaling mediates the coordinate induction of VGLUT2 and Narp triggered by a prolonged increase in glutamatergic synaptic activity.

PubMed

Doyle, Sukhjeevan; Pyndiah, Slovénie; De Gois, Stéphanie; Erickson, Jeffrey D

2010-05-07

Homeostatic scaling of glutamatergic and GABAergic transmission is triggered by prolonged alterations in synaptic neuronal activity. We have previously described a presynaptic mechanism for synaptic homeostasis and plasticity that involves scaling the level of vesicular glutamate (VGLUT1) and gamma-aminobutyric acid (GABA) (VGAT) transporter biosynthesis. These molecular determinants of vesicle filling and quantal size are regulated by neuronal activity in an opposite manner and bi-directionally. Here, we report that a striking induction of VGLUT2 mRNA and synaptic protein is triggered by a prolonged increase in glutamatergic synaptic activity in mature neocortical neuronal networks in vitro together with two determinants of inhibitory synaptic strength, the neuronal activity-regulated pentraxin (Narp), and glutamate decarboxylase (GAD65). Activity-dependent induction of VGLUT2 and Narp exhibits a similar intermediate-early gene response that is blocked by actinomycin D and tetrodotoxin, by inhibitors of ionotropic glutamate receptors and L-type voltage-gated calcium channels, and is dependent on downstream signaling via calmodulin, calcium/calmodulin-dependent protein kinase (CaMK) and extracellular signal-regulated kinase 1/2 (ERK1/2). The co-induction of VGLUT2 and Narp triggered by prolonged gamma-aminobutyric acid type A receptor blockade is independent of brain-derived nerve growth factor and TrkB receptor signaling. VGLUT2 protein induction occurs on a subset of cortically derived synaptic vesicles in excitatory synapses on somata and dendritic processes of multipolar GABAergic interneurons, recognized sites for the clustering of alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionate glutamate receptors by Narp. We propose that VGLUT2 and Narp induction by excitation-transcription coupling leads to increased glutamatergic transmission at synapses on GABAergic inhibitory feedback neurons as part of a coordinated program of Ca(2+)-signal transcription involved in mechanisms of homeostatic plasticity after prolonged hyperactivity.

Nuclear BK Channels Regulate Gene Expression via the Control of Nuclear Calcium Signaling

PubMed Central

Li, Boxing; Jie, Wei; Huang, Lianyan; Wei, Peng; Li, Shuji; Luo, Zhengyi; Friedman, Allyson K.; Meredith, Andrea L.; Han, Ming-Hu; Zhu, Xin-Hong; Gao, Tian-Ming

2014-01-01

Ion channels are essential for the regulation of neuronal functions. The significance of plasma membrane, mitochondrial, endoplasmic reticulum, and lysosomal ion channels in the regulation of Ca2+ is well established. In contrast, surprisingly less is known about the function of ion channels on the nuclear envelope (NE). Here we demonstrate the presence of functional large-conductance, calcium-activated potassium channels (BK channels) on the NE of rodent hippocampal neurons. Functionally blockade of nuclear BK channels (nBK channels) induces NE-derived Ca2+ release, nucleoplasmic Ca2+ elevation, and cAMP response element binding protein (CREB)-dependent transcription. More importantly, blockade of nBK channels regulates nuclear Ca2+-sensitive gene expression and promotes dendritic arborization in a nuclear Ca2+-dependent manner. These results suggest that nBK channel functions as a molecular linker between neuronal activity and nuclear Ca2+ to convey the signals from synapse to nucleus and is a new modulator for synaptic activity-dependent neuronal functions at the NE level. PMID:24952642

Metabolic Regulation of Manganese Superoxide Dismutase Expression via Essential Amino Acid Deprivation*

PubMed Central

Aiken, Kimberly J.; Bickford, Justin S.; Kilberg, Michael S.; Nick, Harry S.

2008-01-01

Organisms respond to available nutrient levels by rapidly adjusting metabolic flux, in part through changes in gene expression. A consequence of adaptations in metabolic rate is the production of mitochondria-derived reactive oxygen species. Therefore, we hypothesized that nutrient sensing could regulate the synthesis of the primary defense of the cell against superoxide radicals, manganese superoxide dismutase. Our data establish a novel nutrient-sensing pathway for manganese superoxide dismutase expression mediated through essential amino acid depletion concurrent with an increase in cellular viability. Most relevantly, our results are divergent from current mechanisms governing amino acid-dependent gene regulation. This pathway requires the presence of glutamine, signaling via the tricarboxylic acid cycle/electron transport chain, an intact mitochondrial membrane potential, and the activity of both the MEK/ERK and mammalian target of rapamycin kinases. Our results provide evidence for convergence of metabolic cues with nutrient control of antioxidant gene regulation, revealing a potential signaling strategy that impacts free radical-mediated mutations with implications in cancer and aging. PMID:18187411

Metabolic regulation of manganese superoxide dismutase expression via essential amino acid deprivation.

PubMed

Aiken, Kimberly J; Bickford, Justin S; Kilberg, Michael S; Nick, Harry S

2008-04-18

Organisms respond to available nutrient levels by rapidly adjusting metabolic flux, in part through changes in gene expression. A consequence of adaptations in metabolic rate is the production of mitochondria-derived reactive oxygen species. Therefore, we hypothesized that nutrient sensing could regulate the synthesis of the primary defense of the cell against superoxide radicals, manganese superoxide dismutase. Our data establish a novel nutrient-sensing pathway for manganese superoxide dismutase expression mediated through essential amino acid depletion concurrent with an increase in cellular viability. Most relevantly, our results are divergent from current mechanisms governing amino acid-dependent gene regulation. This pathway requires the presence of glutamine, signaling via the tricarboxylic acid cycle/electron transport chain, an intact mitochondrial membrane potential, and the activity of both the MEK/ERK and mammalian target of rapamycin kinases. Our results provide evidence for convergence of metabolic cues with nutrient control of antioxidant gene regulation, revealing a potential signaling strategy that impacts free radical-mediated mutations with implications in cancer and aging.

Motivation in vigilance - A test of the goal-setting hypothesis of the effectiveness of knowledge of results.

NASA Technical Reports Server (NTRS)

Warm, J. S.; Riechmann, S. W.; Grasha, A. F.; Seibel, B.

1973-01-01

This study tested the prediction, derived from the goal-setting hypothesis, that the facilitating effects of knowledge of results (KR) in a simple vigilance task should be related directly to the level of the performance standard used to regulate KR. Two groups of Ss received dichotomous KR in terms of whether Ss response times (RTs) to signal detections exceeded a high or low standard of performance. The aperiodic offset of a visual signal was the critical event for detection. The vigil was divided into a training phase followed by testing, during which KR was withdrawn. Knowledge of results enhanced performance in both phases. However, the two standards used to regulate feedback contributed little to these effects.

Peracetylated hydroxytyrosol, a new hydroxytyrosol derivate, attenuates LPS-induced inflammatory response in murine peritoneal macrophages via regulation of non-canonical inflammasome, Nrf2/HO1 and JAK/STAT signaling pathways.

PubMed

Montoya, Tatiana; Aparicio-Soto, Marina; Castejón, María Luisa; Rosillo, María Ángeles; Sánchez-Hidalgo, Marina; Begines, Paloma; Fernández-Bolaños, José G; Alarcón-de-la-Lastra, Catalina

2018-03-18

The present study was designed to investigate the anti-inflammatory effects of a new derivative of hydroxytyrosol (HTy), peracetylated hydroxytyrosol (Per-HTy), compared with its parent, HTy, on lipopolysaccharide (LPS)-stimulated murine macrophages as well as potential signaling pathways involved. In particular, we attempted to characterize the role of the inflammasome underlying Per-HTy possible anti-inflammatory effects. Isolated murine peritoneal macrophages were treated with HTy or its derivative in the presence or absence of LPS (5 μg/ml) for 18 h. Cell viability was determined using sulforhodamine B (SRB) assay. Nitric oxide (NO) production was analyzed by Griess method. Production of pro-inflammatory cytokines was evaluated by enzyme-linked immunosorbent assay (ELISA) and inducible nitric oxide synthase (iNOS) and cyclooxygenase (COX)-2, janus kinase/signal transducer and activator of transcription (JAK/STAT) pathway (STAT3), haem oxigenase 1 (HO1), nuclear factor (erythroid-derived 2)-like 2 (Nrf2) expression and mitogen-activated protein kinases (MAPKs) activation was determined by Western blot. Per-HTy significantly reduced the levels of NO and pro-inflammatory cytokines as well as both COX-2 and iNOS expressions. Furthermore, Per-HTy treatment inhibited STAT3 and increased Nrf2 and HO1 protein levels in murine macrophages exposed to LPS. In addition, Per-HTy anti-inflammatory activity was related with an inhibition of non-canonical nucleotide binding domain (NOD)-like receptor (NLRP3) inflammasome pathways by decreasing pro-inflammatory interleukin (IL)-1β and IL-18 cytokine levels as consequence of regulation of cleaved caspase-11 enzyme. These results support that this new HTy derivative may offer a new promising nutraceutical therapeutic strategy in the management of inflammatory-related pathologies. Copyright © 2018. Published by Elsevier Inc.

Vanillic acid derivatives from the green algae Cladophora socialis as potent protein tyrosine phosphatase 1B inhibitors.

PubMed

Feng, Yunjiang; Carroll, Anthony R; Addepalli, Rama; Fechner, Gregory A; Avery, Vicky M; Quinn, Ronald J

2007-11-01

A novel vanillic acid derivative (1) and its sulfate adduct (2) were isolated from a green algae, Cladophora socialis. The structures of 1 and 2 were elucidated from NMR and HRESIMS experiments. Both compounds showed potent inhibitory activity against protein tyrosine phosphatase 1B (PTP1B), an enzyme involved in the regulation of insulin cell signaling. Compounds 1 and 2 had IC50 values of 3.7 and 1.7 microM, respectively.

A Symphony of Regulations Centered on p63 to Control Development of Ectoderm-Derived Structures

PubMed Central

Guerrini, Luisa; Costanzo, Antonio; Merlo, Giorgio R.

2011-01-01

The p53-related transcription factor p63 is critically important for basic cellular functions during development of the ectoderm and derived structure and tissues, including skin, limb, palate, and hair. On the one side, p63 is required to sustain the proliferation of keratinocyte progenitors, while on the other side it is required for cell stratification, commitment to differentiate, cell adhesion, and epithelial-mesenchymal signaling. Molecules that are components or regulators of the p63 pathway(s) are rapidly being identified, and it comes with no surprise that alterations in the p63 pathway lead to congenital conditions in which the skin and other ectoderm-derived structures are affected. In this paper, we summarize the current knowledge of the molecular and cellular regulations centered on p63, derived from the comprehension of p63-linked human diseases and the corresponding animal models, as well as from cellular models and high-throughput molecular approaches. We point out common themes and features, that allow to speculate on the possible role of p63 downstream events and their potential exploitation in future attempts to correct the congenital defect in preclinical studies. PMID:21716671

Regulation of metabolism and body fat mass by leptin.

PubMed

Baile, C A; Della-Fera, M A; Martin, R J

2000-01-01

The relative stability of body weight over the long term and under a variety of environmental conditions that alter short-term energy intake and expenditure provides strong evidence for the regulation of body energy content. The lipostatic theory of energy balance regulation proposed 40 years ago that circulating factors, generated in proportion to body fat stores, acted as signals to the brain, eliciting changes in energy intake and expenditure. The discovery of leptin and its receptors has now provided a molecular basis for this theory. Leptin functions as much more than an adipocyte-derived signal of lipid stores, however. Although suppression of food intake is an important centrally mediated effect of leptin, considerable evidence indicates that leptin also functions both directly and indirectly, via the brain, to orchestrate complex metabolic changes in a number of organs and tissues, altering nutrient flux to favor energy expenditure over energy storage.

Regulation of superoxide anion production by NADPH oxidase in monocytes/macrophages: contributions to atherosclerosis.

PubMed

Cathcart, Martha K

2004-01-01

Monocyte extravasation into the vessel wall has been shown to be a critical step in the development of atherosclerosis. Upon activation, monocytes produce a burst of superoxide anion due to activation of the NADPH oxidase enzyme complex. Monocyte-derived superoxide anion contributes to oxidant stress in inflammatory sites, is required for monocyte-mediated LDL oxidation, and alters basic cell functions such as adhesion and proliferation. We hypothesize that monocyte-derived superoxide anion production contributes to atherosclerotic lesion formation. In this brief review, we summarize our current understanding of the signal transduction pathways regulating NADPH oxidase activation and related superoxide anion production in activated human monocytes. Novel pathways are identified that may serve as future targets for therapeutic intervention in this pathogenic process. The contributions of superoxide anion and NADPH oxidase to atherogenesis are discussed. Future experiments are needed to clarify the exact role of NADPH oxidase-derived superoxide anion in atherogenesis, particularly that derived from monocytes.

Branched Chain Amino Acids: Beyond Nutrition Metabolism

PubMed Central

2018-01-01

Branched chain amino acids (BCAAs), including leucine (Leu), isoleucine (Ile), and valine (Val), play critical roles in the regulation of energy homeostasis, nutrition metabolism, gut health, immunity and disease in humans and animals. As the most abundant of essential amino acids (EAAs), BCAAs are not only the substrates for synthesis of nitrogenous compounds, they also serve as signaling molecules regulating metabolism of glucose, lipid, and protein synthesis, intestinal health, and immunity via special signaling network, especially phosphoinositide 3-kinase/protein kinase B/mammalian target of rapamycin (PI3K/AKT/mTOR) signal pathway. Current evidence supports BCAAs and their derivatives as the potential biomarkers of diseases such as insulin resistance (IR), type 2 diabetes mellitus (T2DM), cancer, and cardiovascular diseases (CVDs). These diseases are closely associated with catabolism and balance of BCAAs. Hence, optimizing dietary BCAA levels should have a positive effect on the parameters associated with health and diseases. This review focuses on recent findings of BCAAs in metabolic pathways and regulation, and underlying the relationship of BCAAs to related disease processes. PMID:29570613

The Nuclear Receptor AhR Controls Bone Homeostasis by Regulating Osteoclast Differentiation via the RANK/c-Fos Signaling Axis

PubMed Central

Izawa, Takashi; Arakaki, Rieko; Mori, Hiroki; Tsunematsu, Takaaki; Kudo, Yasusei; Tanaka, Eiji

2016-01-01

The aryl hydrocarbon receptor (AhR) pathway plays a key role in receptor activator of NF-κB ligand (RANKL)–mediated osteoclastogenesis. However, the mechanism underlying the regulation of AhR expression in osteoclasts and the signaling pathway through which AhR controls osteoclastogenesis remain unclear. We found that the expression of AhR in bone marrow–derived osteoclasts was upregulated by RANKL at an earlier stage than was the expression of signature osteoclast genes such as those encoding cathepsin K and NFAT, cytoplasmic, calcineurin-dependent 1. In response to RANKL, bone marrow macrophages isolated from AhR−/− mice exhibited impaired phosphorylation of Akt and MAPK as well as NF-κB, whereas their response to M-CSF remained unchanged. Osteoclast differentiation mediated by the AhR signaling pathway was also regulated in an RANKL/c-Fos–dependent manner. Furthermore, ligand activation of AhR by the smoke toxin benzo[a]pyrene accelerated osteoclast differentiation in a receptor-dependent manner, and AhR-dependent regulation of mitochondrial biogenesis in osteoclasts was observed. Moreover, AhR−/− mice exhibited impaired bone healing with delayed endochondral ossification. Taken together, the present results suggest that the RANKL/AhR/c-Fos signaling axis plays a critical role in osteoclastogenesis, thereby identifying the potential of AhR in treating pathological, inflammatory, or metabolic disorders of the bone. PMID:27849171

Post-synaptic BDNF-TrkB Signaling in Synapse Maturation, Plasticity and Disease

PubMed Central

Yoshii, Akira; Constantine-Paton, Martha

2010-01-01

Brain-derived neurotrophic factor (BDNF) is a prototypic neurotrophin that regulates diverse developmental events from the selection of neural progenitors to the terminal dendritic differentiation and connectivity of neurons. We focus here on activity-dependent synaptic regulation by BDNF and its receptor, full length TrkB. BDNF-TrkB signaling is involved in transcription, translation, and trafficking of proteins during various phases of synaptic development and has been implicated in several forms of synaptic plasticity. These functions are carried out by a combination of the three signaling cascades triggered when BDNF binds TrkB: the mitogen-activated protein kinase (MAPK), the phospholipase Cγ (PLC PLCγ), and the phosphatidylinositol 3-kinase (PI3K) pathways. MAPK and PI3K play crucial roles in both translation and/or trafficking of proteins induced by synaptic activity while PLCγ regulates intracellular Ca2+ that can drive transcription via cyclic AMP and a Protein Kinase C. Conversely, the abnormal regulation of BDNF is implicated in various developmental and neurodegenerative diseases that perturb neural development and function. We will discuss the current state of understanding BDNF signaling in the context of synaptic development and plasticity with a focus on the post-synaptic cell and close with the evidence that basic mechanisms of BDNF function still need to be understood in order to effectively treat genetic disruptions of these pathways that cause devastating neurodevelopmental diseases. PMID:20186705

miR-5591-5p regulates the effect of ADSCs in repairing diabetic wound via targeting AGEs/AGER/JNK signaling axis.

PubMed

Li, Qiang; Xia, Sizhan; Yin, Yating; Guo, Yanping; Chen, Feifei; Jin, Peisheng

2018-05-11

Advanced glycation end products/advanced glycation end products receptor (AGEs/AGER) interaction triggers reactive oxygen species (ROS) generation and activates downstream signal pathways and induces apoptosis in endothelial progenitor cells. A number of studies have revealed the involvement of microRNAs (miRNAs) in regulating intracellular ROS production and apoptosis. However, few studies explore the role of miRNAs in regulating the effect of adipose tissue-derived stem cells (ADSCs) in repairing diabetic wound and the associated cellular mechanisms remain unclear. In this study, ADSCs were exposed to AGEs, then siRNA for AGER was transfected into ADSCs. We found that AGEs/AGER axis induced ROS generation and apoptosis in ADSCs. AGEs treatment downregulated miR-5591-5p in ADSCs, which directly targeted AGER. miR-5591-5p suppressed AGEs/AGER axis-mediated ROS generation and apoptosis in ADSCs in vitro. In addition, miR-5591-5p promoted cell survival and enhanced the ability of ADSCs for repairing cutaneous wound in vivo. Furthermore, we confirmed that c-jun kinase (JNK) signal was involved in the inhibitory effect of miR-5591-5p on AGEs/AGER axis-induced ROS generation and apoptosis in ADSCs. Thus, these results indicated that miR-5591-5p targeting AGEs/AGER/JNK signaling axis possibly regulates the effect of ADSCs in repairing diabetic wound.

Controlled branched-chain amino acids auxotrophy in Listeria monocytogenes allows isoleucine to serve as a host signal and virulence effector

PubMed Central

Borovok, Ilya; Sigal, Nadejda

2018-01-01

Listeria monocytogenes (Lm) is a saprophyte and intracellular pathogen. Transition to the pathogenic state relies on sensing of host-derived metabolites, yet it remains unclear how these are recognized and how they mediate virulence gene regulation. We previously found that low availability of isoleucine signals Lm to activate the virulent state. This response is dependent on CodY, a global regulator and isoleucine sensor. Isoleucine-bound CodY represses metabolic pathways including branched-chain amino acids (BCAA) biosynthesis, however under BCAA depletion, as occurs during infection, BCAA biosynthesis is upregulated and isoleucine-unbound CodY activates virulence genes. While isoleucine was revealed as an important input signal, it was not identified how internal levels are controlled during infection. Here we show that Lm regulates BCAA biosynthesis via CodY and via a riboregulator located upstream to the BCAA biosynthesis genes, named Rli60. rli60 is transcribed when BCAA levels drop, forming a ribosome-mediated attenuator that cis-regulates the downstream genes according to BCAA supply. Notably, we found that Rli60 restricts BCAA production, essentially starving Lm, a mechanism that is directly linked to virulence, as it controls the internal isoleucine pool and thereby CodY activity. This controlled BCAA auxotrophy likely evolved to enable isoleucine to serve as a host signal and virulence effector. PMID:29529043

Controlled branched-chain amino acids auxotrophy in Listeria monocytogenes allows isoleucine to serve as a host signal and virulence effector.

PubMed

Brenner, Moran; Lobel, Lior; Borovok, Ilya; Sigal, Nadejda; Herskovits, Anat A

2018-03-01

Listeria monocytogenes (Lm) is a saprophyte and intracellular pathogen. Transition to the pathogenic state relies on sensing of host-derived metabolites, yet it remains unclear how these are recognized and how they mediate virulence gene regulation. We previously found that low availability of isoleucine signals Lm to activate the virulent state. This response is dependent on CodY, a global regulator and isoleucine sensor. Isoleucine-bound CodY represses metabolic pathways including branched-chain amino acids (BCAA) biosynthesis, however under BCAA depletion, as occurs during infection, BCAA biosynthesis is upregulated and isoleucine-unbound CodY activates virulence genes. While isoleucine was revealed as an important input signal, it was not identified how internal levels are controlled during infection. Here we show that Lm regulates BCAA biosynthesis via CodY and via a riboregulator located upstream to the BCAA biosynthesis genes, named Rli60. rli60 is transcribed when BCAA levels drop, forming a ribosome-mediated attenuator that cis-regulates the downstream genes according to BCAA supply. Notably, we found that Rli60 restricts BCAA production, essentially starving Lm, a mechanism that is directly linked to virulence, as it controls the internal isoleucine pool and thereby CodY activity. This controlled BCAA auxotrophy likely evolved to enable isoleucine to serve as a host signal and virulence effector.

Myocyte-Derived Hsp90 Modulates Collagen Upregulation via Biphasic Activation of STAT-3 in Fibroblasts during Cardiac Hypertrophy

PubMed Central

Datta, Ritwik; Bansal, Trisha; Rana, Santanu; Datta, Kaberi; Datta Chaudhuri, Ratul; Chawla-Sarkar, Mamta

2016-01-01

ABSTRACT Signal transducer and activator of transcription 3 (STAT-3)-mediated signaling in relation to upregulated collagen expression in fibroblasts during cardiac hypertrophy is well defined. Our recent findings have identified heat shock protein 90 (Hsp90) to be a critical modulator of fibrotic signaling in cardiac fibroblasts in this disease milieu. The present study was therefore intended to analyze the role of Hsp90 in the STAT-3-mediated collagen upregulation process. Our data revealed a significant difference between in vivo and in vitro results, pointing to a possible involvement of myocyte-fibroblast cross talk in this process. Cardiomyocyte-targeted knockdown of Hsp90 in rats (Rattus norvegicus) in which the renal artery was ligated showed downregulated collagen synthesis. Furthermore, the results obtained with cardiac fibroblasts conditioned with Hsp90-inhibited hypertrophied myocyte supernatant pointed toward cardiomyocytes' role in the regulation of collagen expression in fibroblasts during hypertrophy. Our study also revealed a novel signaling mechanism where myocyte-derived Hsp90 orchestrates not only p65-mediated interleukin-6 (IL-6) synthesis but also its release in exosomal vesicles. Such myocyte-derived exosomes and myocyte-secreted IL-6 are responsible in unison for the biphasic activation of STAT-3 signaling in cardiac fibroblasts that culminates in excess collagen synthesis, leading to severely compromised cardiac function during cardiac hypertrophy. PMID:28031326

Myocyte-Derived Hsp90 Modulates Collagen Upregulation via Biphasic Activation of STAT-3 in Fibroblasts during Cardiac Hypertrophy.

PubMed

Datta, Ritwik; Bansal, Trisha; Rana, Santanu; Datta, Kaberi; Datta Chaudhuri, Ratul; Chawla-Sarkar, Mamta; Sarkar, Sagartirtha

2017-03-15

Signal transducer and activator of transcription 3 (STAT-3)-mediated signaling in relation to upregulated collagen expression in fibroblasts during cardiac hypertrophy is well defined. Our recent findings have identified heat shock protein 90 (Hsp90) to be a critical modulator of fibrotic signaling in cardiac fibroblasts in this disease milieu. The present study was therefore intended to analyze the role of Hsp90 in the STAT-3-mediated collagen upregulation process. Our data revealed a significant difference between in vivo and in vitro results, pointing to a possible involvement of myocyte-fibroblast cross talk in this process. Cardiomyocyte-targeted knockdown of Hsp90 in rats ( Rattus norvegicus ) in which the renal artery was ligated showed downregulated collagen synthesis. Furthermore, the results obtained with cardiac fibroblasts conditioned with Hsp90-inhibited hypertrophied myocyte supernatant pointed toward cardiomyocytes' role in the regulation of collagen expression in fibroblasts during hypertrophy. Our study also revealed a novel signaling mechanism where myocyte-derived Hsp90 orchestrates not only p65-mediated interleukin-6 (IL-6) synthesis but also its release in exosomal vesicles. Such myocyte-derived exosomes and myocyte-secreted IL-6 are responsible in unison for the biphasic activation of STAT-3 signaling in cardiac fibroblasts that culminates in excess collagen synthesis, leading to severely compromised cardiac function during cardiac hypertrophy. Copyright © 2017 American Society for Microbiology.

Purinergic Signaling Regulates the Transforming Growth Factor-β3-Induced Chondrogenic Response of Mesenchymal Stem Cells to Hydrostatic Pressure.

PubMed

Steward, Andrew J; Kelly, Daniel J; Wagner, Diane R

2016-06-01

Although hydrostatic pressure (HP) is known to regulate chondrogenic differentiation of mesenchymal stromal/stem cells (MSCs), improved insight into the mechanotransduction of HP may form the basis for novel tissue engineering strategies. Previously, we demonstrated that matrix stiffness and calcium ion (Ca(++)) mobility regulate the mechanotransduction of HP; however, the mechanisms, by which these Ca(++) signaling pathways are initiated, are currently unknown. The purinergic pathway, in which adenosine triphosphate (ATP) is released and activates P-receptors to initiate Ca(++) signaling, plays a key role in the mechanotransduction of compression, but has yet to be investigated with regard to HP. Therefore, the objective of this study was to investigate the interplay between purinergic signaling, matrix stiffness, and the chondrogenic response of MSCs to HP. Porcine bone marrow-derived MSCs were seeded into soft or stiff agarose hydrogels and subjected to HP (10 MPa at 1 Hz for 4 h/d for 21 days) or kept in free swelling conditions. Stiff constructs were incubated with pharmacological inhibitors of extracellular ATP, P2 receptors, or hemichannels, or without any inhibitors as a control. As with other loading modalities, HP significantly increased ATP release in the control group; however, inhibition of hemichannels completely abrogated this response. The increase in sulfated glycosaminoglycan (sGAG) synthesis and vimentin reorganization observed in the control group in response to HP was suppressed in the presence of all three inhibitors, suggesting that purinergic signaling is involved in the mechanoresponse of MSCs to HP. Interestingly, ATP was released from both soft and stiff hydrogels in response to HP, but HP only enhanced chondrogenesis in the stiff hydrogels, indicating that matrix stiffness may act downstream of purinergic signaling to regulate the mechanoresponse of MSCs to HP. Addition of exogenous ATP did not replicate the effects of HP on chondrogenesis, suggesting that mechanisms other than purinergic signaling also regulate the response of MSCs to HP.

Dopamine D2 Receptor Signaling in the Nucleus Accumbens Comprises a Metabolic-Cognitive Brain Interface Regulating Metabolic Components of Glucose Reinforcement.

PubMed

Michaelides, Michael; Miller, Michael L; DiNieri, Jennifer A; Gomez, Juan L; Schwartz, Elizabeth; Egervari, Gabor; Wang, Gene Jack; Mobbs, Charles V; Volkow, Nora D; Hurd, Yasmin L

2017-11-01

Appetitive drive is influenced by coordinated interactions between brain circuits that regulate reinforcement and homeostatic signals that control metabolism. Glucose modulates striatal dopamine (DA) and regulates appetitive drive and reinforcement learning. Striatal DA D2 receptors (D2Rs) also regulate reinforcement learning and are implicated in glucose-related metabolic disorders. Nevertheless, interactions between striatal D2R and peripheral glucose have not been previously described. Here we show that manipulations involving striatal D2R signaling coincide with perseverative and impulsive-like responding for sucrose, a disaccharide consisting of fructose and glucose. Fructose conveys orosensory (ie, taste) reinforcement but does not convey metabolic (ie, nutrient-derived) reinforcement. Glucose however conveys orosensory reinforcement but unlike fructose, it is a major metabolic energy source, underlies sustained reinforcement, and activates striatal circuitry. We found that mice with deletion of dopamine- and cAMP-regulated neuronal phosphoprotein (DARPP-32) exclusively in D2R-expressing cells exhibited preferential D2R changes in the nucleus accumbens (NAc), a striatal region that critically regulates sucrose reinforcement. These changes coincided with perseverative and impulsive-like responding for sucrose pellets and sustained reinforcement learning of glucose-paired flavors. These mice were also characterized by significant glucose intolerance (ie, impaired glucose utilization). Systemic glucose administration significantly attenuated sucrose operant responding and D2R activation or blockade in the NAc bidirectionally modulated blood glucose levels and glucose tolerance. Collectively, these results implicate NAc D2R in regulating both peripheral glucose levels and glucose-dependent reinforcement learning behaviors and highlight the notion that glucose metabolic impairments arising from disrupted NAc D2R signaling are involved in compulsive and perseverative feeding behaviors.

Systems approach identifies an organic nitrogen-responsive gene network that is regulated by the master clock control gene CCA1.

PubMed

Gutiérrez, Rodrigo A; Stokes, Trevor L; Thum, Karen; Xu, Xiaodong; Obertello, Mariana; Katari, Manpreet S; Tanurdzic, Milos; Dean, Alexis; Nero, Damion C; McClung, C Robertson; Coruzzi, Gloria M

2008-03-25

Understanding how nutrients affect gene expression will help us to understand the mechanisms controlling plant growth and development as a function of nutrient availability. Nitrate has been shown to serve as a signal for the control of gene expression in Arabidopsis. There is also evidence, on a gene-by-gene basis, that downstream products of nitrogen (N) assimilation such as glutamate (Glu) or glutamine (Gln) might serve as signals of organic N status that in turn regulate gene expression. To identify genome-wide responses to such organic N signals, Arabidopsis seedlings were transiently treated with ammonium nitrate in the presence or absence of MSX, an inhibitor of glutamine synthetase, resulting in a block of Glu/Gln synthesis. Genes that responded to organic N were identified as those whose response to ammonium nitrate treatment was blocked in the presence of MSX. We showed that some genes previously identified to be regulated by nitrate are under the control of an organic N-metabolite. Using an integrated network model of molecular interactions, we uncovered a subnetwork regulated by organic N that included CCA1 and target genes involved in N-assimilation. We validated some of the predicted interactions and showed that regulation of the master clock control gene CCA1 by Glu or a Glu-derived metabolite in turn regulates the expression of key N-assimilatory genes. Phase response curve analysis shows that distinct N-metabolites can advance or delay the CCA1 phase. Regulation of CCA1 by organic N signals may represent a novel input mechanism for N-nutrients to affect plant circadian clock function.

A novel synthetic derivative of melatonin, 5-hydroxy-2’-isobutyl-streptochlorin (HIS), inhibits inflammatory responses via regulation of TRIF-dependent signaling and inflammasome activation

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

Shim, Do-Wan; Shin, Hee Jae; Han, Ji-Won

Melatonin is substantially reported to possess anti-inflammatory properties. In the present study, we synthesized a novel melatonin derivative, 5-hydroxy-2′-isobutyl-streptochlorin (HIS), which displayed superior anti-inflammatory properties to its parent compound. Further, we explored its underlying mechanisms in cellular and experimental animal models. Lipopolysaccharide was used to induce in vitro inflammatory responses in RAW 264.7 macrophages. LPS-primed macrophages were pulsed with biologically unrelated toxic molecules to evaluate the role of HIS on inflammasome activation. In vivo verifications were carried out using acute lung injury (ALI) and Escherichia coli-induced septic shock mouse models. HIS inhibited the production of proinflammatory mediators and cytokines suchmore » as nitric oxide, cyclooxygenase 2, IL-1β, IL-6 and TNF-α in LPS-stimulated RAW 264.7 macrophages. HIS suppressed the infiltration of immune cells into the lung and the production of pro-inflammatory cytokines such as IL-6 and TNF-α in broncho-alveolar lavage fluid in the ALI mouse model. Mechanistic studies revealed that the inhibitory effects of HIS were mediated through the regulation of the TIR domain-containing, adaptor-inducing, interferon-β (TRIF)-dependent signaling pathway from toll-like receptors. Further, HIS attenuated IL-1β secretion via the inhibition of NLRP3 inflammasome activation independent of mitochondrial ROS production. Furthermore, HIS suppressed IL-1β, IL-6 and interferon-β production in peritoneal lavage in the Escherichia coli-induced sepsis mouse model. In conclusion, HIS exerted potent anti-inflammatory effects via the regulation of TRIF-dependent signaling and inflammasome activation. Notably, the superior anti-inflammatory properties of this derivative compared with its parent compound could be a promising lead for treating various inflammatory-mediated diseases. - Highlights: • Νovel compound, 5-hydroxy-2′-isobutyl-streptochlorin (HIS) was synthesized. • HIS inhibited TRIF-dependent signaling induced by LPS stimulation. • HIS inhibited NLRP3 inflammasome activation. • HIS inhibited acute lung injury and Escherichia coli-induced septic shock.« less

Magnolol inhibits angiogenesis by regulating ROS-mediated apoptosis and the PI3K/AKT/mTOR signaling pathway in mES/EB-derived endothelial-like cells.

PubMed

Kim, Gi Dae; Oh, Jedo; Park, Hyen-Joo; Bae, Kihwan; Lee, Sang Kook

2013-08-01

Magnolol, a neolignan from the traditional medicinal plant Magnolia obovata, has been shown to possess neuroprotective, anti-inflammatory, anticancer and anti-angiogenic activities. However, the precise mechanism of the anti-angiogenic activity of magnolol remains to be elucidated. In the present study, the anti-angiogenic effect of magnolol was evaluated in mouse embryonic stem (mES)/embryoid body (EB)-derived endothelial-like cells. The endothelial-like cells were obtained by differentiation from mES/EB cells. Magnolol (20 µM) significantly suppressed the transcriptional and translational expression of platelet endothelial cell adhesion molecule (PECAM), an endothelial biomarker, in mES/EB-derived endothelial-like cells. To further understand the molecular mechanism of the suppression of PECAM expression, signaling pathways were analyzed in the mES/EB-derived endothelial-like cells. Magnolol induced the generation of reactive oxygen species (ROS) by mitochondria, a process that was associated with the induction of apoptosis as determined by positive Annexin V staining and the activation of cleaved caspase-3. The involvement of ROS generation by magnolol was confirmed by treatment with an antioxidant, N-acetyl-cysteine (NAC). NAC inhibited the magnolol-mediated induction of ROS generation and suppression of PECAM expression. In addition, magnolol suppressed the activation of MAPKs (ERK, JNK and p38) and the PI3K/AKT/mTOR signaling pathway in mES/EB-derived endothelial-like cells. Taken together, these findings demonstrate for the first time that the anti-angiogenic activity of magnolol may be associated with ROS-mediated apoptosis and the suppression of the PI3K/AKT/mTOR signaling pathway in mES/EB-derived endothelial-like cells.

Transcriptional control of Sost in bone [Transcriptional control of Sclerostin

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

Sebastian, Aimy; Loots, Gabriela G.

Sclerostin is an osteocyte derived negative regulator of bone formation. A highly specific expression pattern and the exclusive bone phenotype have made Sclerostin an attractive target for therapeutic intervention in treating metabolic bone diseases such as osteoporosis and in facilitating fracture repair. Understanding the molecular mechanisms that regulate Sclerostin transcription is of great interest as it may unveil new avenues for therapeutic approaches. Such studies may also elucidate how various signaling pathways intersect to modulate bone metabolism. Furthermore we review the current understanding of the upstream molecular mechanisms that regulate Sost/SOST transcription, in bone.

Transcriptional control of Sost in bone [Transcriptional control of Sclerostin

DOE PAGES

Sebastian, Aimy; Loots, Gabriela G.

2016-10-19

Sclerostin is an osteocyte derived negative regulator of bone formation. A highly specific expression pattern and the exclusive bone phenotype have made Sclerostin an attractive target for therapeutic intervention in treating metabolic bone diseases such as osteoporosis and in facilitating fracture repair. Understanding the molecular mechanisms that regulate Sclerostin transcription is of great interest as it may unveil new avenues for therapeutic approaches. Such studies may also elucidate how various signaling pathways intersect to modulate bone metabolism. Furthermore we review the current understanding of the upstream molecular mechanisms that regulate Sost/SOST transcription, in bone.

A Modular Library of Small Molecule Signals Regulates Social Behaviors in Caenorhabditis elegans

PubMed Central

Bose, Neelanjan; Zaslaver, Alon; Mahanti, Parag; Ho, Margaret C.; O'Doherty, Oran G.; Edison, Arthur S.; Sternberg, Paul W.; Schroeder, Frank C.

2012-01-01

The nematode C. elegans is an important model for the study of social behaviors. Recent investigations have shown that a family of small molecule signals, the ascarosides, controls population density sensing and mating behavior. However, despite extensive studies of C. elegans aggregation behaviors, no intraspecific signals promoting attraction or aggregation of wild-type hermaphrodites have been identified. Using comparative metabolomics, we show that the known ascarosides are accompanied by a series of derivatives featuring a tryptophan-derived indole moiety. Behavioral assays demonstrate that these indole ascarosides serve as potent intraspecific attraction and aggregation signals for hermaphrodites, in contrast to ascarosides lacking the indole group, which are repulsive. Hermaphrodite attraction to indole ascarosides depends on the ASK amphid sensory neurons. Downstream of the ASK sensory neuron, the interneuron AIA is required for mediating attraction to indole ascarosides instead of the RMG interneurons, which previous studies have shown to integrate attraction and aggregation signals from ASK and other sensory neurons. The role of the RMG interneuron in mediating aggregation and attraction is thought to depend on the neuropeptide Y-like receptor NPR-1, because solitary and social C. elegans strains are distinguished by different npr-1 variants. We show that indole ascarosides promote attraction and aggregation in both solitary and social C. elegans strains. The identification of indole ascarosides as aggregation signals reveals unexpected complexity of social signaling in C. elegans, which appears to be based on a modular library of ascarosides integrating building blocks derived from lipid β-oxidation and amino-acid metabolism. Variation of modules results in strongly altered signaling content, as addition of a tryptophan-derived indole unit to repellent ascarosides produces strongly attractive indole ascarosides. Our findings show that the library of ascarosides represents a highly developed chemical language integrating different neurophysiological pathways to mediate social communication in C. elegans. PMID:22253572

Mast Cell Interactions and Crosstalk in Regulating Allergic Inflammation.

PubMed

Velez, Tania E; Bryce, Paul J; Hulse, Kathryn E

2018-04-17

This review summarizes recent findings on mast cell biology with a focus on IgE-independent roles of mast cells in regulating allergic responses. Recent studies have described novel mast cell-derived molecules, both secreted and membrane-bound, that facilitate cross-talk with a variety of immune effector cells to mediate type 2 inflammatory responses. Mast cells are complex and dynamic cells that are persistent in allergy and are capable of providing signals that lead to the initiation and persistence of allergic mechanisms.

Age-Dependent Deficits in Fear Learning in Heterozygous BDNF Knock-Out Mice

ERIC Educational Resources Information Center

Endres, Thomas; Lessmann, Volkmar

2012-01-01

Beyond its trophic function, the neurotrophin BDNF (brain-derived neurotrophic factor) is well known to crucially mediate synaptic plasticity and memory formation. Whereas recent studies suggested that acute BDNF/TrkB signaling regulates amygdala-dependent fear learning, no impairments of cued fear learning were reported in heterozygous BDNF…

Basal Lamina Mimetic Nanofibrous Peptide Networks for Skeletal Myogenesis

NASA Astrophysics Data System (ADS)

Yasa, I. Ceren; Gunduz, Nuray; Kilinc, Murat; Guler, Mustafa O.; Tekinay, Ayse B.

2015-11-01

Extracellular matrix (ECM) is crucial for the coordination and regulation of cell adhesion, recruitment, differentiation and death. Therefore, equilibrium between cell-cell and cell-matrix interactions and matrix-associated signals are important for the normal functioning of cells, as well as for regeneration. In this work, we describe importance of adhesive signals for myoblast cells’ growth and differentiation by generating a novel ECM mimetic peptide nanofiber scaffold system. We show that not only structure but also composition of bioactive signals are important for cell adhesion, growth and differentiation by mimicking the compositional and structural properties of native skeletal muscle basal lamina. We conjugated laminin-derived integrin binding peptide sequence, “IKVAV”, and fibronectin-derived well known adhesive sequence, “RGD”, into peptide nanostructures to provide adhesive and myogenic cues on a nanofibrous morphology. The myogenic and adhesive signals exhibited a synergistic effect on model myoblasts, C2C12 cells. Our results showed that self-assembled peptide nanofibers presenting laminin derived epitopes support adhesion, growth and proliferation of the cells and significantly promote the expression of skeletal muscle-specific marker genes. The functional peptide nanofibers used in this study present a biocompatible and biodegradable microenvironment, which is capable of supporting the growth and differentiation of C2C12 myoblasts into myotubes.

Basal Lamina Mimetic Nanofibrous Peptide Networks for Skeletal Myogenesis

PubMed Central

Yasa, I. Ceren; Gunduz, Nuray; Kilinc, Murat; Guler, Mustafa O.; Tekinay, Ayse B.

2015-01-01

Extracellular matrix (ECM) is crucial for the coordination and regulation of cell adhesion, recruitment, differentiation and death. Therefore, equilibrium between cell-cell and cell-matrix interactions and matrix-associated signals are important for the normal functioning of cells, as well as for regeneration. In this work, we describe importance of adhesive signals for myoblast cells’ growth and differentiation by generating a novel ECM mimetic peptide nanofiber scaffold system. We show that not only structure but also composition of bioactive signals are important for cell adhesion, growth and differentiation by mimicking the compositional and structural properties of native skeletal muscle basal lamina. We conjugated laminin-derived integrin binding peptide sequence, “IKVAV”, and fibronectin-derived well known adhesive sequence, “RGD”, into peptide nanostructures to provide adhesive and myogenic cues on a nanofibrous morphology. The myogenic and adhesive signals exhibited a synergistic effect on model myoblasts, C2C12 cells. Our results showed that self-assembled peptide nanofibers presenting laminin derived epitopes support adhesion, growth and proliferation of the cells and significantly promote the expression of skeletal muscle-specific marker genes. The functional peptide nanofibers used in this study present a biocompatible and biodegradable microenvironment, which is capable of supporting the growth and differentiation of C2C12 myoblasts into myotubes. PMID:26555958

RhoA and RhoC are involved in stromal cell-derived factor-1-induced cell migration by regulating F-actin redistribution and assembly.

PubMed

Luo, Jixian; Li, Dingyun; Wei, Dan; Wang, Xiaoguang; Wang, Lan; Zeng, Xianlu

2017-12-01

Stromal cell-derived factor-1 (SDF-1) signaling is important to the maintenance and progression of T-cell acute lymphoblastic leukemia by inducing chemotaxis migration. To identify the mechanism of SDF-1 signaling in the migration of T-ALL, Jurkat acute lymphoblastic leukemia cells were used. Results showed that SDF-1 induces Jurkat cell migration by F-actin redistribution and assembly, which is dependent on Rho activity. SDF-1 induced RhoA and RhoC activation, as well as reactive oxygen species (ROS) production, which was inhibited by Rho inhibitor. The Rho-dependent ROS production led to subsequent cytoskeleton redistribution and assembly in the process of migration. Additionally, RhoA and RhoC were involved in SDF-1-induced Jurkat cell migration. Taken together, we found a SDF-1/CXCR4-RhoA and RhoC-ROS-cytoskeleton pathway that regulates Jurkat cell migration in response to SDF-1. This work will contribute to a clearer insight into the migration mechanism of acute lymphoblastic leukemia.

Inhibition of strigolactone receptors by N-phenylanthranilic acid derivatives: Structural and functional insights.

PubMed

Hamiaux, Cyril; Drummond, Revel S M; Luo, Zhiwei; Lee, Hui Wen; Sharma, Prachi; Janssen, Bart J; Perry, Nigel B; Denny, William A; Snowden, Kimberley C

2018-04-27

The strigolactone (SL) family of plant hormones regulates a broad range of physiological processes affecting plant growth and development and also plays essential roles in controlling interactions with parasitic weeds and symbiotic fungi. Recent progress elucidating details of SL biosynthesis, signaling, and transport offers many opportunities for discovering new plant-growth regulators via chemical interference. Here, using high-throughput screening and downstream biochemical assays, we identified N -phenylanthranilic acid derivatives as potent inhibitors of the SL receptors from petunia (DAD2), rice (OsD14), and Arabidopsis (AtD14). Crystal structures of DAD2 and OsD14 in complex with inhibitors further provided detailed insights into the inhibition mechanism, and in silico modeling of 19 other plant strigolactone receptors suggested that these compounds are active across a large range of plant species. Altogether, these results provide chemical tools for investigating SL signaling and further define a framework for structure-based approaches to design and validate optimized inhibitors of SL receptors for specific plant targets. © 2018 by The American Society for Biochemistry and Molecular Biology, Inc.

The canonical Wnt signaling activator, R-spondin2, regulates craniofacial patterning and morphogenesis within the branchial arch through ectodermal-mesenchymal interaction

PubMed Central

Jin, Yong-Ri; Turcotte, Taryn J.; Crocker, Alison L.; Han, Xiang Hua; Yoon, Jeong Kyo

2011-01-01

R-spondins are a recently characterized family of secreted proteins that activate Wnt/β-catenin signaling. Herein, we determine R-spondin2 (Rspo2) function in craniofacial development in mice. Mice lacking a functional Rspo2 gene exhibit craniofacial abnormalities such as mandibular hypoplasia, maxillary and mandibular skeletal deformation, and cleft palate. We found that loss of the mouse Rspo2 gene significantly disrupted Wnt/β-catenin signaling and gene expression within the first branchial arch (BA1). Rspo2, which is normally expressed in BA1 mesenchymal cells, regulates gene expression through a unique ectoderm-mesenchyme interaction loop. The Rspo2 protein, potentially in combination with ectoderm-derived Wnt ligands, up-regulates Msx1 and Msx2 expression within mesenchymal cells. In contrast, Rspo2 regulates expression of the Dlx5, Dlx6, and Hand2 genes in mesenchymal cells via inducing expression of their upstream activator, Endothelin1 (Edn1), within ectodermal cells. Loss of Rspo2 also causes increased cell apoptosis, especially within the aboral (or caudal) domain of the BA1, resulting in hypoplasia of the BA1. Severely reduced expression of Fgf8, a survival factor for mesenchymal cells, in the ectoderm of Rspo2−/− embryos is likely responsible for increased cell apoptosis. Additionally, we found that cleft palate in Rspo2−/− mice is not associated with defects intrinsic to the palatal shelves. A possible cause of cleft palate is a delay of proper palatal shelf elevation that may result from the small mandible and a failure of lowering the tongue. Thus, our study identifies Rspo2 as a mesenchyme-derived factor that plays critical roles in regulating BA1 patterning and morphogenesis through ectodermal-mesenchymal interaction and a novel genetic factor for cleft palate. PMID:21237142

Inhibition of RHO-ROCK signaling enhances ICM and suppresses TE characteristics through activation of Hippo signaling in the mouse blastocyst

PubMed Central

Kono, Kanako; Tamashiro, Dana Ann A.; Alarcon, Vernadeth B.

2014-01-01

Specification of the trophectoderm (TE) and inner cell mass (ICM) lineages in the mouse blastocyst correlates with cell position, as TE derives from outer cells whereas ICM from inner cells. Differences in position are reflected by cell polarization and Hippo signaling. Only in outer cells, the apical-basal cell polarity is established, and Hippo signaling is inhibited in such a manner that LATS1 and 2 (LATS1/2) kinases are prevented from phosphorylating YAP, a key transcriptional co-activator of the TE-specifying gene Cdx2. However, the molecular mechanisms that regulate these events are not fully understood. Here, we showed that inhibition of RHO-ROCK signaling enhances ICM and suppresses TE characteristics through activation of Hippo signaling and disruption of apical-basal polarity. Embryos treated with ROCK inhibitor Y-27632 exhibited elevated expression of ICM marker NANOG and reduced expression of CDX2 at the blastocyst stage. Y-27632-treated embryos failed to accumulate YAP in the nucleus, although it was rescued by concomitant inhibition of LATS1/2. Segregation between apical and basal polarity regulators, namely PARD6B, PRKCZ, SCRIB, and LLGL1, was dampened by Y-27632 treatment, whereas some of the polarization events at the late 8-cell stage such as compaction and apical localization of p-ERM and tyrosinated tubulin occurred normally. Similar abnormalities of Hippo signaling and apical-basal polarization were also observed in embryos that were treated with RHO GTPases inhibitor. These results suggest that RHO-ROCK signaling plays an essential role in regulating Hippo signaling and cell polarization to enable proper specification of the ICM and TE lineages. PMID:24997360

Wnt signaling maintains the notochord fate for progenitor cells and supports the posterior extension of the notochord.

PubMed

Ukita, Kanako; Hirahara, Shino; Oshima, Naoko; Imuta, Yu; Yoshimoto, Aki; Jang, Chuan-Wei; Oginuma, Masayuki; Saga, Yumiko; Behringer, Richard R; Kondoh, Hisato; Sasaki, Hiroshi

2009-10-01

The notochord develops from notochord progenitor cells (NPCs) and functions as a major signaling center to regulate trunk and tail development. NPCs are initially specified in the node by Wnt and Nodal signals at the gastrula stage. However, the underlying mechanism that maintains the NPCs throughout embryogenesis to contribute to the posterior extension of the notochord remains unclear. Here, we demonstrate that Wnt signaling in the NPCs is essential for posterior extension of the notochord. Genetic labeling revealed that the Noto-expressing cells in the ventral node contribute the NPCs that reside in the tail bud. Robust Wnt signaling in the NPCs was observed during posterior notochord extension. Genetic attenuation of the Wnt signal via notochord-specific beta-catenin gene ablation resulted in posterior truncation of the notochord. In the NPCs of such mutant embryos, the expression of notochord-specific genes was down-regulated, and an endodermal marker, E-cadherin, was observed. No significant alteration of cell proliferation or apoptosis of the NPCs was detected. Taken together, our data indicate that the NPCs are derived from Noto-positive node cells, and are not fully committed to a notochordal fate. Sustained Wnt signaling is required to maintain the NPCs' notochordal fate.

It’s a lipid’s world: Bioactive lipid metabolism and signaling in neural stem cell differentiation

PubMed Central

Bieberich, Erhard

2012-01-01

Lipids are often considered membrane components whose function is to embed proteins into cell membranes. In the last two decades, studies on brain lipids have unequivocally demonstrated that many lipids have critical cell signaling functions; they are called “bioactive lipids”. Pioneering work in Dr. Robert Ledeen’s laboratory has shown that two bioactive brain sphingolipids, sphingomyelin and the ganglioside GM1 are major signaling lipids in the nuclear envelope. In addition to derivatives of the sphingolipid ceramide, the bioactive lipids discussed here belong to the classes of terpenoids and steroids, eicosanoids, and lysophospholipids. These lipids act mainly through two mechanisms: 1) direct interaction between the bioactive lipid and a specific protein binding partner such as a lipid receptor, protein kinase or phosphatase, ion exchanger, or other cell signaling protein; and 2) formation of lipid microdomains or rafts that regulate the activity of a group of raft-associated cell signaling proteins. In recent years, a third mechanism has emerged, which invokes lipid second messengers as a regulator for the energy and redox balance of differentiating neural stem cells (NSCs). Interestingly, developmental niches such as the stem cell niche for adult NSC differentiation may also be metabolic compartments that respond to a distinct combination of bioactive lipids. The biological function of these lipids as regulators of NSC differentiation will be reviewed and their application in stem cell therapy discussed. PMID:22246226

Genetic reduction of embryonic leukemia-inhibitory factor production rescues placentation in SOCS3-null embryos but does not prevent inflammatory disease.

PubMed

Robb, Lorraine; Boyle, Kristy; Rakar, Steven; Hartley, Lynne; Lochland, Janelle; Roberts, Andrew W; Alexander, Warren S; Metcalf, Donald

2005-11-08

The suppressor of cytokine-signaling (SOCS) proteins act as negative-feedback inhibitors of cytokine and growth-factor-induced signal transduction. In vivo studies have implicated SOCS3 as a negative regulator of signaling downstream of gp130, the receptor subunit shared by IL-6-like cytokines. Mice lacking SOCS3 die at midgestation because of placental failure, and SOCS3 ablation in a cell-type-specific manner results in changes in the functional outcome of gp130 signaling in response to IL-6. In this study, we show that genetic reduction of leukemia-inhibitory factor (LIF) production by embryo-derived tissues is sufficient to prevent the placental defect. This establishes LIF signaling as a major physiological regulator of trophoblast differentiation in vivo. Mice deficient in both SOCS3 and LIF are born in predicted numbers and appear normal at birth but exhibit failure to thrive and high neonatal mortality. Adult SOCS3-null mice on a LIF-null background succumb to a spontaneous fatal inflammatory disease characterized by neutrophilia and inflammatory-cell tissue infiltrates. The disease spectrum mimics that seen in mice with a conditional deletion of SOCS3 in hematopoietic and endothelial cells, extending the evidence for a major role for SOCS3 in the homeostatic regulation of the inflammatory response and indicates that LIF is not required for this process.

Genetic reduction of embryonic leukemia-inhibitory factor production rescues placentation in SOCS3-null embryos but does not prevent inflammatory disease

PubMed Central

Robb, Lorraine; Boyle, Kristy; Rakar, Steven; Hartley, Lynne; Lochland, Janelle; Roberts, Andrew W.; Alexander, Warren S.; Metcalf, Donald

2005-01-01

The suppressor of cytokine-signaling (SOCS) proteins act as negative-feedback inhibitors of cytokine and growth-factor-induced signal transduction. In vivo studies have implicated SOCS3 as a negative regulator of signaling downstream of gp130, the receptor subunit shared by IL-6-like cytokines. Mice lacking SOCS3 die at midgestation because of placental failure, and SOCS3 ablation in a cell-type-specific manner results in changes in the functional outcome of gp130 signaling in response to IL-6. In this study, we show that genetic reduction of leukemia-inhibitory factor (LIF) production by embryo-derived tissues is sufficient to prevent the placental defect. This establishes LIF signaling as a major physiological regulator of trophoblast differentiation in vivo. Mice deficient in both SOCS3 and LIF are born in predicted numbers and appear normal at birth but exhibit failure to thrive and high neonatal mortality. Adult SOCS3-null mice on a LIF-null background succumb to a spontaneous fatal inflammatory disease characterized by neutrophilia and inflammatory-cell tissue infiltrates. The disease spectrum mimics that seen in mice with a conditional deletion of SOCS3 in hematopoietic and endothelial cells, extending the evidence for a major role for SOCS3 in the homeostatic regulation of the inflammatory response and indicates that LIF is not required for this process. PMID:16258063

Sprouty Is a Negative Regulator of Transforming Growth Factor β–Induced Epithelial-to-Mesenchymal Transition and Cataract

PubMed Central

Shin, Eun Hye H; Basson, M Albert; Robinson, Michael L; McAvoy, John W; Lovicu, Frank J

2012-01-01

Fibrosis affects an extensive range of organs and is increasingly acknowledged as a major component of many chronic disorders. It is now well accepted that the elevated expression of certain inflammatory cell–derived cytokines, especially transforming growth factor β (TGFβ), is involved in the epithelial-to-mesenchymal transition (EMT) leading to the pathogenesis of a diverse range of fibrotic diseases. In lens, aberrant TGFβ signaling has been shown to induce EMT leading to cataract formation. Sproutys (Sprys) are negative feedback regulators of receptor tyrosine kinase (RTK)-signaling pathways in many vertebrate systems, and in this study we showed that they are important in the murine lens for promoting the lens epithelial cell phenotype. Conditional deletion of Spry1 and Spry2 specifically from the lens leads to an aberrant increase in RTK-mediated extracellular signal-regulated kinase 1/2 phosphorylation and, surprisingly, elevated TGFβ-related signaling in lens epithelial cells, leading to an EMT and subsequent cataract formation. Conversely, increased Spry overexpression in lens cells can suppress not only TGFβ-induced signaling, but also the accompanying EMT and cataract formation. On the basis of these findings, we propose that a better understanding of the relationship between Spry and TGFβ signaling will not only elucidate the etiology of lens pathology, but will also lead to the development of treatments for other fibrotic-related diseases associated with TGFβ-induced EMT. PMID:22517312

Nuclear factor-κB modulates osteogenesis of periodontal ligament stem cells through competition with β-catenin signaling in inflammatory microenvironments

PubMed Central

Chen, X; Hu, C; Wang, G; Li, L; Kong, X; Ding, Y; Jin, Y

2013-01-01

Inflammation can influence multipotency and self-renewal of mesenchymal stem cells (MSCs), resulting in their awakened bone-regeneration ability. Human periodontal ligament tissue-derived MSCs (PDLSCs) have been isolated, and their differentiation potential was found to be defective due to β-catenin signaling indirectly regulated by inflammatory microenvironments. Nuclear factor-κB (NF-κB) is well studied in inflammation by many different groups. The role of NF-κB needs to be studied in PDLSCs, although genetic evidences have recently shown that NF-κB inhibits osteoblastic bone formation in mice. However, the mechanism as to how inflammation leads to the modulation of β-catenin and NF-κB signaling remains unclear. In this study, we investigated β-catenin and NF-κB signaling through regulation of glycogen synthase kinase 3β activity (GSK-3β, which modulates β-catenin and NF-κB signaling) using a specific inhibitor LiCl and a phosphatidylinositol 3-kinase (PI3K) inhibitor LY 294002. We identified that NF-κB signaling might be more important for the regulation of osteogenesis in PDLSCs from periodontitis compared with β-catenin. BAY 11-7082 (an inhibitor of NF-κB) could inhibit phosphorylation of p65 and partly rescue the differentiation potential of PDLSCs in inflammation. Our data indicate that NF-κB has a central role in regulating osteogenic differentiation of PDLSCs in inflammatory microenvironments. Given the molecular mechanisms of NF-κB in osteogenic differentiation governed by inflammation, it can be said that NF-κB helps in improving stem cell-mediated inflammatory bone disease therapy. PMID:23449446

The Transcription Factor ABI4 Is Required for the Ascorbic Acid–Dependent Regulation of Growth and Regulation of Jasmonate-Dependent Defense Signaling Pathways in Arabidopsis[C][W

PubMed Central

Kerchev, Pavel I.; Pellny, Till K.; Vivancos, Pedro Diaz; Kiddle, Guy; Hedden, Peter; Driscoll, Simon; Vanacker, Hélène; Verrier, Paul; Hancock, Robert D.; Foyer, Christine H.

2011-01-01

Cellular redox homeostasis is a hub for signal integration. Interactions between redox metabolism and the ABSCISIC ACID-INSENSITIVE-4 (ABI4) transcription factor were characterized in the Arabidopsis thaliana vitamin c defective1 (vtc1) and vtc2 mutants, which are defective in ascorbic acid synthesis and show a slow growth phenotype together with enhanced abscisic acid (ABA) levels relative to the wild type (Columbia-0). The 75% decrease in the leaf ascorbate pool in the vtc2 mutants was not sufficient to adversely affect GA metabolism. The transcriptome signatures of the abi4, vtc1, and vtc2 mutants showed significant overlap, with a large number of transcription factors or signaling components similarly repressed or induced. Moreover, lincomycin-dependent changes in LIGHT HARVESTING CHLOROPHYLL A/B BINDING PROTEIN 1.1 expression were comparable in these mutants, suggesting overlapping participation in chloroplast to nucleus signaling. The slow growth phenotype of vtc2 was absent in the abi4 vtc2 double mutant, as was the sugar-insensitive phenotype of the abi4 mutant. Octadecanoid derivative-responsive AP2/ERF-domain transcription factor 47 (ORA47) and AP3 (an ABI5 binding factor) transcripts were enhanced in vtc2 but repressed in abi4 vtc2, suggesting that ABI4 and ascorbate modulate growth and defense gene expression through jasmonate signaling. We conclude that low ascorbate triggers ABA- and jasmonate-dependent signaling pathways that together regulate growth through ABI4. Moreover, cellular redox homeostasis exerts a strong influence on sugar-dependent growth regulation. PMID:21926335

Fat cells reactivate quiescent neuroblasts via TOR and glial insulin relays in Drosophila.

PubMed

Sousa-Nunes, Rita; Yee, Lih Ling; Gould, Alex P

2011-03-24

Many stem, progenitor and cancer cells undergo periods of mitotic quiescence from which they can be reactivated. The signals triggering entry into and exit from this reversible dormant state are not well understood. In the developing Drosophila central nervous system, multipotent self-renewing progenitors called neuroblasts undergo quiescence in a stereotypical spatiotemporal pattern. Entry into quiescence is regulated by Hox proteins and an internal neuroblast timer. Exit from quiescence (reactivation) is subject to a nutritional checkpoint requiring dietary amino acids. Organ co-cultures also implicate an unidentified signal from an adipose/hepatic-like tissue called the fat body. Here we provide in vivo evidence that Slimfast amino-acid sensing and Target of rapamycin (TOR) signalling activate a fat-body-derived signal (FDS) required for neuroblast reactivation. Downstream of this signal, Insulin-like receptor signalling and the Phosphatidylinositol 3-kinase (PI3K)/TOR network are required in neuroblasts for exit from quiescence. We demonstrate that nutritionally regulated glial cells provide the source of Insulin-like peptides (ILPs) relevant for timely neuroblast reactivation but not for overall larval growth. Conversely, ILPs secreted into the haemolymph by median neurosecretory cells systemically control organismal size but do not reactivate neuroblasts. Drosophila thus contains two segregated ILP pools, one regulating proliferation within the central nervous system and the other controlling tissue growth systemically. Our findings support a model in which amino acids trigger the cell cycle re-entry of neural progenitors via a fat-body-glia-neuroblasts relay. This mechanism indicates that dietary nutrients and remote organs, as well as local niches, are key regulators of transitions in stem-cell behaviour.

miR-138-mediated Regulation of Kindlin-2 Expression Modulates Sensitivity to Chemotherapeutics

PubMed Central

Sossey-Alaoui, Khalid; Plow, Edward F.

2015-01-01

Prostate cancer (PCa) is the second leading cause of cancer-related death in men, second only to lung cancer, mainly due to disease reoccurrence as a result to lack of response to androgen deprivation therapies (ADT) after castration. Patients with metastatic castration-resistant prostate cancer (mCRPC) have very limited treatment options, with docetaxel as the first line standard of care, for which resistance to this chemotherapeutic ultimately develops. Therefore, finding ways to sensitize tumors to chemotherapies and to limit chemoresistance provides a viable strategy to extend the survival of mCRPC patients. The present study investigated the role of Kindlin-2 (FERMT2/K2), a member of the Kindlin family of FERM domain proteins and key regulators of the adhesive functions mediated by integrin, in the sensitization of mCRPC to chemotherapeutics. Loss of K2, which is overexpressed in PCa cells derived from mCRPC tumors, compared to those cells derived from androgen-dependent tumors, significantly enhanced apoptosis and cell death of docetaxel-treated PC3 cells. Furthermore, it was determined that K2-mediated sensitization to docetaxel treatment is the result of inhibition of β1-integrin signaling. Finally, miR-138 specifically targeted K2 and inhibited its expression, thereby regulating a miR-138/K2/β1-integrin signaling axis in mCRPC that is critical for the modulation of sensitivity to chemotherapeutics. Thus, these data identify a novel signaling axis where K2 in combination with chemotherapeutics provides a new target for the treatment of mCRPC. PMID:26474967

B and T Lymphocyte Attenuator Down-regulation by HIV-1 Depends on Type I Interferon and Contributes to T-Cell Hyperactivation

PubMed Central

Zhang, Zheng; Xu, Xiangsheng; Lu, Jiyun; Zhang, Shuye; Gu, Lanlan; Fu, Junliang; Jin, Lei; Li, Haiying; Zhao, Min; Zhang, Jiyuan; Wu, Hao; Su, Lishan; Fu, Yang-Xin

2011-01-01

Background. Nonspecific T-cell hyperactivation is the main driving force for human immunodeficiency virus (HIV)–1 disease progression, but the reasons why the excess immune response is not properly shut off are poorly defined. Methods. Eighty-five HIV-1–infected individuals were enrolled to characterize B and T lymphocyte attenuator (BTLA) expression and function. Infection and blockade assays were used to dissect the factors that influenced BTLA signaling in vitro. Results. BTLA expression on overall CD4+ and CD8+ T cells was progressively decreased in HIV-1 infection, which was directly correlated with disease progression and CD4+ T-cell differentiation and activation. BTLA+CD4+ T cells from HIV-1–infected patients also displayed an altered immune status, which was indicated by reduced expression of naive markers but increased activation and exhaustion markers. Cross-linking of BTLA can substantially decrease CD4+ T-cell activation in vitro. This responsiveness of CD4+ T cells to BTLA-mediated inhibitory signaling was further found to be impaired in HIV-1–infected patients. Furthermore, HIV-1 NL4-3 down-regulated BTLA expression on CD4+ T cells dependent on plasmacytoid dendritic cell (pDC)-derived interferon (IFN)-α. Blockade of IFN-α or depletion of pDCs prevents HIV-1-induced BTLA down-regulation. Conclusions. HIV-1 infection potentially impairs BTLA-mediated signaling dependent on pDC-derived IFN-α, which may contribute to broad T-cell hyperactivation induced by chronic HIV-1 infection. PMID:21592997

The Src-like adaptor protein regulates GM-CSFR signaling and monocytic dendritic cell maturation.

PubMed

Liontos, Larissa M; Dissanayake, Dilan; Ohashi, Pamela S; Weiss, Arthur; Dragone, Leonard L; McGlade, C Jane

2011-02-15

GM-CSF is an important cytokine involved in myeloid differentiation and inflammatory processes. Signaling through the GM-CSFR also plays a critical role in the generation of monocyte-derived dendritic cells (DC). In this article, we report that the Src-like adaptor protein (SLAP) functions as a negative regulator of the GM-CSFR. In bone marrow-derived DC (BM-DC) lacking SLAP and the closely related SLAP2, downregulation of GM-CSFRβ is impaired, leading to enhanced phosphorylation of Jak2 and prolonged activation of Akt and Erk1/2 in response to GM-CSF stimulation. Compared with wild-type bone marrow, SLAP/SLAP2(-/-) bone marrow gave rise to similar numbers of CD11c(+) and CD11b(+) DC, but SLAP/SLAP2(-/-) BM-DC failed to acquire high levels of MHC class II, CD80, and CD86, indicating an impairment in maturation. Furthermore, MHC class II expression in SLAP/SLAP2(-/-) BM-DC was rescued by decreasing GM-CSF concentration, suggesting that enhanced GM-CSF signaling mediates the block in maturation. In addition, SLAP/SLAP2(-/-) BM-DC produced less IL-12 and TNF-α in response to LPS compared with controls and failed to stimulate T cells in an MLR. Ag-specific T cell activation assays showed that SLAP/SLAP2(-/-) BM-DC were less robust at inducing IFN-γ secretion by DO11.10 T cells. These results indicated that SLAP-mediated GM-CSFR regulation is important for the generation of functionally mature monocytic DC.

Untargeted metabolomics analysis reveals dynamic changes in azelaic acid- and salicylic acid derivatives in LPS-treated Nicotiana tabacum cells.

PubMed

Mhlongo, M I; Tugizimana, F; Piater, L A; Steenkamp, P A; Madala, N E; Dubery, I A

2017-01-22

To counteract biotic stress factors, plants employ multilayered defense mechanisms responsive to pathogen-derived elicitor molecules, and regulated by different phytohormones and signaling molecules. Here, lipopolysaccharide (LPS), a microbe-associated molecular pattern (MAMP) molecule, was used to induce defense responses in Nicotiana tabacum cell suspensions. Intracellular metabolites were extracted with methanol and analyzed using a liquid chromatography-mass spectrometry (UHPLC-qTOF-MS/MS) platform. The generated data were processed and examined with multivariate and univariate statistical tools. The results show time-dependent dynamic changes and accumulation of glycosylated signaling molecules, specifically those of azelaic acid, salicylic acid and methyl-salicylate as contributors to the altered metabolomic state in LPS-treated cells. Copyright © 2016 Elsevier Inc. All rights reserved.

Trifunctional lipid probes for comprehensive studies of single lipid species in living cells

PubMed Central

Nadler, André; Haberkant, Per; Kirkpatrick, Joanna; Schifferer, Martina; Stein, Frank; Hauke, Sebastian; Porter, Forbes D.; Schultz, Carsten

2017-01-01

Lipid-mediated signaling events regulate many cellular processes. Investigations of the complex underlying mechanisms are difficult because several different methods need to be used under varying conditions. Here we introduce multifunctional lipid derivatives to study lipid metabolism, lipid−protein interactions, and intracellular lipid localization with a single tool per target lipid. The probes are equipped with two photoreactive groups to allow photoliberation (uncaging) and photo–cross-linking in a sequential manner, as well as a click-handle for subsequent functionalization. We demonstrate the versatility of the design for the signaling lipids sphingosine and diacylglycerol; uncaging of the probe for these two species triggered calcium signaling and intracellular protein translocation events, respectively. We performed proteomic screens to map the lipid-interacting proteome for both lipids. Finally, we visualized a sphingosine transport deficiency in patient-derived Niemann−Pick disease type C fibroblasts by fluorescence as well as correlative light and electron microscopy, pointing toward the diagnostic potential of such tools. We envision that this type of probe will become important for analyzing and ultimately understanding lipid signaling events in a comprehensive manner. PMID:28154130

Inhibition of extracellular matrix mediated TGF-β signalling suppresses endometrial cancer metastasis

PubMed Central

Sahoo, Subhransu S.; Quah, Min Yuan; Nielsen, Sarah; Atkins, Joshua; Au, Gough G.; Cairns, Murray J.; Nahar, Pravin; Lombard, Janine M.; Tanwar, Pradeep S.

2017-01-01

Although aggressive invasion and distant metastases are an important cause of morbidity and mortality in patients with endometrial cancer (EC), the requisite events determining this propensity are currently unknown. Using organotypic three-dimensional culture of endometrial cancer cell lines, we demonstrated anti-correlated TGF-β signalling gene expression patterns that arise among extracellular matrix (ECM)-attached cells. TGF-β pathway seemed to be active in EC cells forming non-glandular colonies in 3D-matrix but weaker in glandular colonies. Functionally we found that out of several ECM proteins, fibronectin relatively promotes Smad phosphorylation suggesting a potential role in regulating TGF-β signalling in non-glandular colonies. Importantly, alteration of TGF-β pathway induced EMT and MET in both type of colonies through slug protein. The results exemplify a crucial role of TGF-β pathway during EC metastasis in human patients and inhibition of the pathway in a murine model impaired tumour cell invasion and metastasis depicting an attractive target for therapeutic intervention of malignant tumour progression. These findings provide key insights into the role of ECM-derived TGF-β signalling to promote endometrial cancer metastasis and offer an avenue for therapeutic targeting of microenvironment derived signals along with tumour cells. PMID:29069715

A fungicide-responsive kinase as a tool for synthetic cell fate regulation.

PubMed

Furukawa, Kentaro; Hohmann, Stefan

2015-08-18

Engineered biological systems that precisely execute defined tasks have major potential for medicine and biotechnology. For instance, gene- or cell-based therapies targeting pathogenic cells may replace time- and resource-intensive drug development. Engineering signal transduction systems is a promising, yet presently underexplored approach. Here, we exploit a fungicide-responsive heterologous histidine kinase for pathway engineering and synthetic cell fate regulation in the budding yeast Saccharomyces cerevisiae. Rewiring the osmoregulatory Hog1 MAPK signalling system generates yeast cells programmed to execute three different tasks. First, a synthetic negative feedback loop implemented by employing the fungicide-responsive kinase and a fungicide-resistant derivative reshapes the Hog1 activation profile, demonstrating how signalling dynamics can be engineered. Second, combinatorial integration of different genetic parts including the histidine kinases, a pathway activator and chemically regulated promoters enables control of yeast growth and/or gene expression in a two-input Boolean logic manner. Finally, we implemented a genetic 'suicide attack' system, in which engineered cells eliminate target cells and themselves in a specific and controllable manner. Taken together, fungicide-responsive kinases can be applied in different constellations to engineer signalling behaviour. Sensitizing engineered cells to existing chemicals may be generally useful for future medical and biotechnological applications. © The Author(s) 2015. Published by Oxford University Press on behalf of Nucleic Acids Research.

Stress, Epigenetics, and Alcoholism

PubMed Central

Moonat, Sachin; Pandey, Subhash C.

2012-01-01

Acute and chronic stressors have been associated with alterations in mood and increased anxiety that may eventually result in the development of stress-related psychiatric disorders. Stress and associated disorders, including anxiety, are key factors in the development of alcoholism because alcohol consumption can temporarily reduce the drinker’s dysphoria. One molecule that may help mediate the relationship between stress and alcohol consumption is brain-derived neurotrophic factor (BDNF), a protein that regulates the structure and function of the sites where two nerve cells interact and exchange nerve signals (i.e., synapses) and which is involved in numerous physiological processes. Aberrant regulation of BDNF signaling and alterations in synapse activity (i.e., synaptic plasticity) have been associated with the pathophysiology of stress-related disorders and alcoholism. Mechanisms that contribute to the regulation of genetic information without modification of the DNA sequence (i.e., epigenetic mechanisms) may play a role in the complex control of BDNF signaling and synaptic plasticity—for example, by modifying the structure of the DNA–protein complexes (i.e., chromatin) that make up the chromosomes and thereby modulating the expression of certain genes. Studies regarding the epigenetic control of BDNF signaling and synaptic plasticity provide a promising direction to understand the mechanisms mediating the interaction between stress and alcoholism. PMID:23584115

Potential role of retinoids in ovarian physiology and pathogenesis of polycystic ovary syndrome.

PubMed

Jiang, Yanwen; Li, Chunjin; Chen, Lu; Wang, Fengge; Zhou, Xu

2017-06-01

Retinoids (retinol and its derivatives) are required for maintaining vision, immunity, barrier function, reproduction, embryogenesis, cell proliferation and differentiation. Furthermore, retinoid signaling plays a key role in initiating meiosis of germ cells of the mammalian fetal ovary. Recently, studies indicated that precise retinoid level regulation in the ovary provides a molecular control of ovarian development, steroidogenesis and oocyte maturation. Besides, abnormal retinoid signaling may be involved in the pathogenesis of polycystic ovary syndrome (PCOS), one of the most common ovarian endocrinopathies in reproductive-aged women worldwide. This review primarily summarizes recent advancements made in investigating the action of retinoid signaling in ovarian physiology as well as the abnormal retinoid signaling in PCOS. Copyright © 2017. Published by Elsevier B.V.

Neurotrophin signaling endosomes; biogenesis, regulation, and functions

PubMed Central

Yamashita, Naoya; Kuruvilla, Rejji

2016-01-01

In the nervous system, communication between neurons and their post-synaptic target cells is critical for the formation, refinement and maintenance of functional neuronal connections. Diffusible signals secreted by target tissues, exemplified by the family of neurotrophins, impinge on nerve terminals to influence diverse developmental events including neuronal survival and axonal growth. Key mechanisms of action of target-derived neurotrophins include the cell biological processes of endocytosis and retrograde trafficking of their Trk receptors from growth cones to cell bodies. In this review, we summarize the molecular mechanisms underlying this endosome-mediated signaling, focusing on the instructive role of neurotrophin signaling itself in directing its own trafficking. Recent studies have linked impaired neurotrophin trafficking to neurodevelopmental disorders, highlighting the relevance of neurotrophin endosomes in human health. PMID:27327126

BDNF–ERK–CREB signalling mediates the role of miR-132 in the regulation of the effects of oleanolic acid in male mice

PubMed Central

Yi, Li-Tao; Li, Jing; Liu, Bin-Bin; Luo, Liu; Liu, Qing; Geng, Di

2014-01-01

Background Although previous study has demonstrated that brain-derived neurotrophic factor (BDNF) is involved in the antidepressant-like effect of oleanolic acid, there is little information regarding the details of the molecular mechanism involved in this effect. Methods We used a chronic unpredictable mild stress (CUMS) model to test the antidepressant-like effect of oleanolic acid on depressant-like behaviour, miR-132 expression and synaptic protein expression in the male mouse hippocampus. Furthermore, we explored the possible signalling pathways associated with miR-132 expression that mediate the effect of oleanolic acid on neuronal proliferation. Results The results demonstrated that a 3-week treatment with oleanolic acid ameliorated CUMS-induced anhedonic and anxiogenic behaviours. Furthermore, we found that oleanolic acid led to the BDNF-related phosphorylation and activation of extracellular signal-regulated kinases (ERK) and cyclic adenosine monophosphate response element binding protein (CREB), which was associated with the upregulation of miR-132 and hippocampal neuronal proliferation. Moreover, experiments with an miR-132 antagomir revealed that targeting miR-132 led to inhibition of neuronal proliferation and the postsynaptic density protein 95, but did not affect presynaptic protein synapsin I. Limitations Several other stimuli can also induce CREB phosphorylation in the hippocampus. Thus, regulation of miR-132 may not be restricted to neurotrophic signalling. Conclusion Our results show that oleanolic acid induces the upregulation of miR-132, which serves as an important regulator of neurotrophic actions, mainly through the activation of the hippocampal BDNF–ERK–CREB signalling pathways. PMID:25079084

FGF23 regulates renal sodium handling and blood pressure

PubMed Central

Andrukhova, Olena; Slavic, Svetlana; Smorodchenko, Alina; Zeitz, Ute; Shalhoub, Victoria; Lanske, Beate; Pohl, Elena E; Erben, Reinhold G

2014-01-01

Fibroblast growth factor-23 (FGF23) is a bone-derived hormone regulating renal phosphate reabsorption and vitamin D synthesis in renal proximal tubules. Here, we show that FGF23 directly regulates the membrane abundance of the Na+:Cl− co-transporter NCC in distal renal tubules by a signaling mechanism involving the FGF receptor/αKlotho complex, extracellular signal-regulated kinase 1/2 (ERK1/2), serum/glucocorticoid-regulated kinase 1 (SGK1), and with-no lysine kinase-4 (WNK4). Renal sodium (Na+) reabsorption and distal tubular membrane expression of NCC are reduced in mouse models of Fgf23 and αKlotho deficiency. Conversely, gain of FGF23 function by injection of wild-type mice with recombinant FGF23 or by elevated circulating levels of endogenous Fgf23 in Hyp mice increases distal tubular Na+ uptake and membrane abundance of NCC, leading to volume expansion, hypertension, and heart hypertrophy in a αKlotho and dietary Na+-dependent fashion. The NCC inhibitor chlorothiazide abrogates FGF23-induced volume expansion and heart hypertrophy. Our findings suggest that FGF23 is a key regulator of renal Na+ reabsorption and plasma volume, and may explain the association of FGF23 with cardiovascular risk in chronic kidney disease patients. PMID:24797667

IFN-α regulates Blimp-1 expression via miR-23a and miR-125b in both monocytes-derived DC and pDC.

PubMed

Parlato, Stefania; Bruni, Roberto; Fragapane, Paola; Salerno, Debora; Marcantonio, Cinzia; Borghi, Paola; Tataseo, Paola; Ciccaglione, Anna Rita; Presutti, Carlo; Romagnoli, Giulia; Bozzoni, Irene; Belardelli, Filippo; Gabriele, Lucia

2013-01-01

Type I interferon (IFN-I) have emerged as crucial mediators of cellular signals controlling DC differentiation and function. Human DC differentiated from monocytes in the presence of IFN-α (IFN-α DC) show a partially mature phenotype and a special capability of stimulating CD4+ T cell and cross-priming CD8+ T cells. Likewise, plasmacytoid DC (pDC) are blood DC highly specialized in the production of IFN-α in response to viruses and other danger signals, whose functional features may be shaped by IFN-I. Here, we investigated the molecular mechanisms stimulated by IFN-α in driving human monocyte-derived DC differentiation and performed parallel studies on peripheral unstimulated and IFN-α-treated pDC. A specific miRNA signature was induced in IFN-α DC and selected miRNAs, among which miR-23a and miR-125b, proved to be negatively associated with up-modulation of Blimp-1 occurring during IFN-α-driven DC differentiation. Of note, monocyte-derived IFN-α DC and in vitro IFN-α-treated pDC shared a restricted pattern of miRNAs regulating Blimp-1 expression as well as some similar phenotypic, molecular and functional hallmarks, supporting the existence of a potential relationship between these DC populations. On the whole, these data uncover a new role of Blimp-1 in human DC differentiation driven by IFN-α and identify Blimp-1 as an IFN-α-mediated key regulator potentially accounting for shared functional features between IFN-α DC and pDC.

IFN-α Regulates Blimp-1 Expression via miR-23a and miR-125b in Both Monocytes-Derived DC and pDC

PubMed Central

Parlato, Stefania; Salerno, Debora; Marcantonio, Cinzia; Borghi, Paola; Tataseo, Paola; Ciccaglione, Anna Rita; Presutti, Carlo; Romagnoli, Giulia; Bozzoni, Irene; Belardelli, Filippo; Gabriele, Lucia

2013-01-01

Type I interferon (IFN-I) have emerged as crucial mediators of cellular signals controlling DC differentiation and function. Human DC differentiated from monocytes in the presence of IFN-α (IFN-α DC) show a partially mature phenotype and a special capability of stimulating CD4+ T cell and cross-priming CD8+ T cells. Likewise, plasmacytoid DC (pDC) are blood DC highly specialized in the production of IFN-α in response to viruses and other danger signals, whose functional features may be shaped by IFN-I. Here, we investigated the molecular mechanisms stimulated by IFN-α in driving human monocyte-derived DC differentiation and performed parallel studies on peripheral unstimulated and IFN-α-treated pDC. A specific miRNA signature was induced in IFN-α DC and selected miRNAs, among which miR-23a and miR-125b, proved to be negatively associated with up-modulation of Blimp-1 occurring during IFN-α-driven DC differentiation. Of note, monocyte-derived IFN-α DC and in vitro IFN-α-treated pDC shared a restricted pattern of miRNAs regulating Blimp-1 expression as well as some similar phenotypic, molecular and functional hallmarks, supporting the existence of a potential relationship between these DC populations. On the whole, these data uncover a new role of Blimp-1 in human DC differentiation driven by IFN-α and identify Blimp-1 as an IFN-α-mediated key regulator potentially accounting for shared functional features between IFN-α DC and pDC. PMID:23977359

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

Shi, Xue-Feng; Department of Experimental Hematology, Beijing Institute of Radiation Medicine, Beijing 100850; Department of Respiration, Qinghai Provincial People's Hospital, Xining

MicroRNA-486 (miR-486) was first identified from human fetal liver cDNA library and validated as a regulator of hematopoiesis. Its roles in regulating the biological function of bone marrow-derived mesnechymal stem cells (BM-MSCs) under hypoxia have not been explored yet. In this study, we demonstrated that exposure to hypoxia upregulates miR-486 expression in BM-MSCs. Lentivirus-mediated overexpression of miR-486 resulted in increase of hepatocyte growth factor (HGF) and vascular endothelial growth factor(VEGF) in both mRNA and protein levels. MiR-486 expression also promotes proliferation and reduces apoptosis of BM-MSCs. Whereas MiR-486 knockdown downregulated the secretion of HGF and VEGF and induced apoptosis ofmore » BM-MSCs. Furthermore, PTEN-PI3K/AKT signaling was validated to be involved in changes of BM-MSC biological functions regulated by miR-486. These results suggested that MiR-486 mediated the hypoxia-induced angiogenic activity and promoted the proliferation and survival of BM-MSCs through regulating PTEN-PI3K/AKT signaling. These findings might provide a novel understanding of effective therapeutic strategy for hypoxic-ischemic diseases. - Highlights: • miR-486 is a hypoxia-induced miRNA. • miR-486 regulates the secretion of HGF and VEGF, promotes proliferation, and inhibits apoptosis of BM-MSCs. • miR-486 enhances PI3K/AKT activity signaling by targeting PTEN molecule.« less

Anti-Inflammatory Effects of Omega-3 Fatty Acids in the Brain: Physiological Mechanisms and Relevance to Pharmacology.

PubMed

Layé, Sophie; Nadjar, Agnès; Joffre, Corinne; Bazinet, Richard P

2018-01-01

Classically, polyunsaturated fatty acids (PUFA) were largely thought to be relatively inert structural components of brain, largely important for the formation of cellular membranes. Over the past 10 years, a host of bioactive lipid mediators that are enzymatically derived from arachidonic acid, the main n-6 PUFA, and docosahexaenoic acid, the main n-3 PUFA in the brain, known to regulate peripheral immune function, have been detected in the brain and shown to regulate microglia activation. Recent advances have focused on how PUFA regulate the molecular signaling of microglia, especially in the context of neuroinflammation and behavior. Several active drugs regulate brain lipid signaling and provide proof of concept for targeting the brain. Because brain lipid metabolism relies on a complex integration of diet, peripheral metabolism, including the liver and blood, which supply the brain with PUFAs that can be altered by genetics, sex, and aging, there are many pathways that can be disrupted, leading to altered brain lipid homeostasis. Brain lipid signaling pathways are altered in neurologic disorders and may be viable targets for the development of novel therapeutics. In this study, we discuss in particular how n-3 PUFAs and their metabolites regulate microglia phenotype and function to exert their anti-inflammatory and proresolving activities in the brain. Copyright © 2017 by The American Society for Pharmacology and Experimental Therapeutics.

Transcriptional activation of human mu-opioid receptor gene by insulin-like growth factor-I in neuronal cells is modulated by the transcription factor REST.

PubMed

Bedini, Andrea; Baiula, Monica; Spampinato, Santi

2008-06-01

The human mu-opioid receptor gene (OPRM1) promoter contains a DNA sequence binding the repressor element 1 silencing transcription factor (REST) that is implicated in transcriptional repression. We investigated whether insulin-like growth factor I (IGF-I), which affects various aspects of neuronal induction and maturation, regulates OPRM1 transcription in neuronal cells in the context of the potential influence of REST. A series of OPRM1-luciferase promoter/reporter constructs were transfected into two neuronal cell models, neuroblastoma-derived SH-SY5Y cells and PC12 cells. In the former, endogenous levels of human mu-opioid receptor (hMOPr) mRNA were evaluated by real-time PCR. IGF-I up-regulated OPRM1 transcription in: PC12 cells lacking REST, in SH-SY5Y cells transfected with constructs deficient in the REST DNA binding element, or when REST was down-regulated in retinoic acid-differentiated cells. IGF-I activates the signal transducer and activator of transcription-3 signaling pathway and this transcription factor, binding to the signal transducer and activator of transcription-1/3 DNA element located in the promoter, increases OPRM1 transcription. We propose that a reduction in REST is a critical switch enabling IGF-I to up-regulate hMOPr. These findings help clarify how hMOPr expression is regulated in neuronal cells.

The chemokine receptor CCR1 is identified in mast cell-derived exosomes.

PubMed

Liang, Yuting; Qiao, Longwei; Peng, Xia; Cui, Zelin; Yin, Yue; Liao, Huanjin; Jiang, Min; Li, Li

2018-01-01

Mast cells are important effector cells of the immune system, and mast cell-derived exosomes carrying RNAs play a role in immune regulation. However, the molecular function of mast cell-derived exosomes is currently unknown, and here, we identify differentially expressed genes (DEGs) in mast cells and exosomes. We isolated mast cells derived exosomes through differential centrifugation and screened the DEGs from mast cell-derived exosomes, using the GSE25330 array dataset downloaded from the Gene Expression Omnibus database. Biochemical pathways were analyzed by Gene ontology (GO) annotation and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway on the online tool DAVID. DEGs-associated protein-protein interaction networks (PPIs) were constructed using the STRING database and Cytoscape software. The genes identified from these bioinformatics analyses were verified by qRT-PCR and Western blot in mast cells and exosomes. We identified 2121 DEGs (843 up and 1278 down-regulated genes) in HMC-1 cell-derived exosomes and HMC-1 cells. The up-regulated DEGs were classified into two significant modules. The chemokine receptor CCR1 was screened as a hub gene and enriched in cytokine-mediated signaling pathway in module one. Seven genes, including CCR1, CD9, KIT, TGFBR1, TLR9, TPSAB1 and TPSB2 were screened and validated through qRT-PCR analysis. We have achieved a comprehensive view of the pivotal genes and pathways in mast cells and exosomes and identified CCR1 as a hub gene in mast cell-derived exosomes. Our results provide novel clues with respect to the biological processes through which mast cell-derived exosomes modulate immune responses.

Site-Selective Regulation of Platelet-Derived Growth Factor β Receptor Tyrosine Phosphorylation by T-Cell Protein Tyrosine Phosphatase

PubMed Central

Persson, Camilla; Sävenhed, Catrine; Bourdeau, Annie; Tremblay, Michel L.; Markova, Boyka; Böhmer, Frank D.; Haj, Fawaz G.; Neel, Benjamin G.; Elson, Ari; Heldin, Carl-Henrik; Rönnstrand, Lars; Östman, Arne; Hellberg, Carina

2004-01-01

The platelet-derived growth factor (PDGF) β receptor mediates mitogenic and chemotactic signals. Like other tyrosine kinase receptors, the PDGF β receptor is negatively regulated by protein tyrosine phosphatases (PTPs). To explore whether T-cell PTP (TC-PTP) negatively regulates the PDGF β receptor, we compared PDGF β receptor tyrosine phosphorylation in wild-type and TC-PTP knockout (ko) mouse embryos. PDGF β receptors were hyperphosphorylated in TC-PTP ko embryos. Fivefold-higher ligand-induced receptor phosphorylation was observed in TC-PTP ko mouse embryo fibroblasts (MEFs) as well. Reexpression of TC-PTP partly abolished this difference. As determined with site-specific phosphotyrosine antibodies, the extent of hyperphosphorylation varied among different autophosphorylation sites. The phospholipase Cγ1 binding site Y1021, previously implicated in chemotaxis, displayed the largest increase in phosphorylation. The increase in Y1021 phosphorylation was accompanied by increased phospholipase Cγ1 activity and migratory hyperresponsiveness to PDGF. PDGF β receptor tyrosine phosphorylation in PTP-1B ko MEFs but not in PTPɛ ko MEFs was also higher than that in control cells. This increase occurred with a site distribution different from that seen after TC-PTP depletion. PDGF-induced migration was not increased in PTP-1B ko cells. In summary, our findings identify TC-PTP as a previously unrecognized negative regulator of PDGF β receptor signaling and support the general notion that PTPs display site selectivity in their action on tyrosine kinase receptors. PMID:14966296

The suppression of ghrelin signaling mitigates age-associated thermogenic impairment

PubMed Central

Bongmba, Odelia Y. N.; Ma, Xiaojun; Zhu, Xiongwei; Sheikh-Hamad, David; Sun, Yuxiang

2014-01-01

Aging is associated with severe thermogenic impairment, which contributes to obesity and diabetes in aging. We previously reported that ablation of the ghrelin receptor, growth hormone secretagogue receptor (GHS-R), attenuates age-associated obesity and insulin resistance. Ghrelin and obestatin are derived from the same preproghrelin gene. Here we showed that in brown adipocytes, ghrelin decreases the expression of thermogenic regulator but obestatin increases it, thus showing the opposite effects. We also found that during aging, plasma ghrelin and GHS-R expression in brown adipose tissue (BAT) are increased, but plasma obestatin is unchanged. Increased plasma ghrelin and unchanged obestatin during aging may lead to an imbalance of thermogenic regulation, which may in turn exacerbate thermogenic impairment in aging. Moreover, we found that GHS-R ablation activates thermogenic signaling, enhances insulin activation, increases mitochondrial biogenesis, and improves mitochondrial dynamics of BAT. In addition, we detected increased norepinephrine in the circulation, and observed that GHS-R knockdown in brown adipocytes directly stimulates thermogenic activity, suggesting that GHS-R regulates thermogenesis via both central and peripheral mechanisms. Collectively, our studies demonstrate that ghrelin signaling is an important thermogenic regulator in aging. Antagonists of GHS-R may serve as unique anti-obesity agents, combating obesity by activating thermogenesis. PMID:25543537

Hydrogen Sulfide and Reactive Sulfur Species Impact Proteome S-Sulfhydration and Global Virulence Regulation in Staphylococcus aureus.

PubMed

Peng, Hui; Zhang, Yixiang; Palmer, Lauren D; Kehl-Fie, Thomas E; Skaar, Eric P; Trinidad, Jonathan C; Giedroc, David P

2017-10-13

Hydrogen sulfide (H 2 S) is thought to protect bacteria from oxidative stress, but a comprehensive understanding of its function in bacteria is largely unexplored. In this study, we show that the human pathogen Staphylococcus aureus (S. aureus) harbors significant effector molecules of H 2 S signaling, reactive sulfur species (RSS), as low molecular weight persulfides of bacillithiol, coenzyme A, and cysteine, and significant inorganic polysulfide species. We find that proteome S-sulfhydration, a post-translational modification (PTM) in H 2 S signaling, is widespread in S. aureus. RSS levels modulate the expression of secreted virulence factors and the cytotoxicity of the secretome, consistent with an S-sulfhydration-dependent inhibition of DNA binding by MgrA, a global virulence regulator. Two previously uncharacterized thioredoxin-like proteins, denoted TrxP and TrxQ, are S-sulfhydrated in sulfide-stressed cells and are capable of reducing protein hydrodisulfides, suggesting that this PTM is potentially regulatory in S. aureus. In conclusion, our results reveal that S. aureus harbors a pool of proteome- and metabolite-derived RSS capable of impacting protein activities and gene regulation and that H 2 S signaling can be sensed by global regulators to affect the expression of virulence factors.

Antizyme restrains centrosome amplification by regulating the accumulation of Mps1 at centrosomes.

PubMed

Kasbek, Christopher; Yang, Ching-Hui; Fisk, Harold A

2010-11-15

Extra centrosomes are found in many tumors, and their appearance is an early event that can generate aberrant mitotic spindles and aneuploidy. Because the failure to appropriately degrade the Mps1 protein kinase correlates with centrosome overproduction in tumor-derived cells, defects in the factors that promote Mps1 degradation may contribute to extra centrosomes in tumors. However, while we have recently characterized an Mps1 degradation signal, the factors that regulate Mps1 centrosomal Mps1 are unknown. Antizyme (OAZ), a mediator of ubiquitin-independent degradation and a suspected tumor suppressor, was recently shown to localize to centrosomes and modulate centrosome overproduction, but the known OAZ substrates were not responsible for its effect on centrosomes. We have found that OAZ exerts its effect on centrosomes via Mps1. OAZ promotes the removal of Mps1 from centrosomes, and centrosome overproduction caused by reducing OAZ activity requires Mps1. OAZ binds to Mps1 via the Mps1 degradation signal and modulates the function of Mps1 in centrosome overproduction. Moreover, OAZ regulates the canonical centrosome duplication cycle, and reveals a function for Mps1 in procentriole assembly. Together, our data suggest that OAZ restrains the assembly of centrioles by controlling the levels of centrosomal Mps1 through the Cdk2-regulated Mps1 degradation signal.

Immunosuppressive Activity of Daphnetin, One of Coumarin Derivatives, Is Mediated through Suppression of NF-κB and NFAT Signaling Pathways in Mouse T Cells

PubMed Central

Liu, Yan; Xu, Sisi; Huang, Guoren; Xiong, Ying; Zhang, Shuang; Xu, Linli; Deng, Xuming; Guan, Shuang

2014-01-01

Daphnetin, a plant-derived dihydroxylated derivative of coumarin, is an effective compound extracted from a plant called Daphne Korean Nakai. Coumarin derivates were known for their antithrombotic, anti-inflammatory, and antioxidant activities. The present study was aimed to determine the immunosuppressive effects and the underlying mechanisms of daphnetin on concanavalin A (ConA) induced T lymphocytes in mice. We showed that, in vitro, daphnetin suppressed ConA-induced splenocyte proliferation, influenced production of the cytokines and inhibited cell cycle progression through the G0/G1 transition. The data also revealed that daphnetin could down-regulate activation of ConA induced NF-κB and NFAT signal transduction pathways in mouse T lymphocyte. In vivo, daphnetin treatment significantly inhibited the 2, 4- dinitrofluorobenzene (DNFB) -induced delayed type hypersensitivity (DTH) reactions in mice. Collectively, daphnetin had strong immunosuppressive activity both in vitro and in vivo, suggesting a potential role for daphnetin as an immunosuppressive agent, and established the groundwork for further research on daphnetin. PMID:24800925

Cell-derived microparticles: new targets in the therapeutic management of disease.

PubMed

Roseblade, Ariane; Luk, Frederick; Rawling, Tristan; Ung, Alison; Grau, Georges E R; Bebawy, Mary

2013-01-01

Intercellular communication is essential to maintain vital physiological activities and to regulate the organism's phenotype. There are a number of ways in which cells communicate with one another. This can occur via autocrine signaling, endocrine signaling or by the transfer of molecular mediators across gap junctions. More recently communication via microvesicular shedding has gained important recognition as a significant pathway by which cells can coordinate the spread and dominance of selective traits within a population. Through this communication apparatus, cells can now acquire and secure a survival advantage, particularly in the context of malignant disease. This review aims to highlight some of the functions and implications of microparticles in physiology of various disease states, and present a novel therapeutic strategy through the regulation of microparticle production.

Diet and cognition: interplay between cell metabolism and neuronal plasticity.

PubMed

Gomez-Pinilla, Fernando; Tyagi, Ethika

2013-11-01

To discuss studies in humans and animals revealing the ability of foods to benefit the brain: new information with regards to mechanisms of action and the treatment of neurological and psychiatric disorders. Dietary factors exert their effects on the brain by affecting molecular events related to the management of energy metabolism and synaptic plasticity. Energy metabolism influences neuronal function, neuronal signaling, and synaptic plasticity, ultimately affecting mental health. Epigenetic regulation of neuronal plasticity appears as an important mechanism by which foods can prolong their effects on long-term neuronal plasticity. The prime focus of the discussion is to emphasize the role of cell metabolism as a mediator for the action of foods on the brain. Oxidative stress promotes damage to phospholipids present in the plasma membrane such as the omega-3 fatty acid docosahexenoic acid, disrupting neuronal signaling. Thus, dietary docosahexenoic acid seems crucial for supporting plasma membrane function, interneuronal signaling, and cognition. The dual action of brain-derived neurotrophic factor in neuronal metabolism and synaptic plasticity is crucial for activating signaling cascades under the action of diet and other environmental factors, using mechanisms of epigenetic regulation.

G protein-coupled receptor 56 regulates mechanical overload-induced muscle hypertrophy.

PubMed

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

2014-11-04

Peroxisome proliferator-activated receptor gamma coactivator 1-alpha 4 (PGC-1α4) is a protein isoform derived by alternative splicing of the PGC1α 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-1α4 and is induced in humans by resistance exercise. Furthermore, the anabolic effects of PGC-1α4 in cultured murine muscle cells are dependent on GPR56 signaling, because knockdown of GPR56 attenuates PGC-1α4-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 Gα12/13 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.

Light exposure at night disrupts host/cancer circadian regulatory dynamics: impact on the Warburg effect, lipid signaling and tumor growth prevention.

PubMed

Blask, David E; Dauchy, Robert T; Dauchy, Erin M; Mao, Lulu; Hill, Steven M; Greene, Michael W; Belancio, Victoria P; Sauer, Leonard A; Davidson, Leslie

2014-01-01

The central circadian clock within the suprachiasmatic nucleus (SCN) plays an important role in temporally organizing and coordinating many of the processes governing cancer cell proliferation and tumor growth in synchrony with the daily light/dark cycle which may contribute to endogenous cancer prevention. Bioenergetic substrates and molecular intermediates required for building tumor biomass each day are derived from both aerobic glycolysis (Warburg effect) and lipid metabolism. Using tissue-isolated human breast cancer xenografts grown in nude rats, we determined that circulating systemic factors in the host and the Warburg effect, linoleic acid uptake/metabolism and growth signaling activities in the tumor are dynamically regulated, coordinated and integrated within circadian time structure over a 24-hour light/dark cycle by SCN-driven nocturnal pineal production of the anticancer hormone melatonin. Dim light at night (LAN)-induced melatonin suppression disrupts this circadian-regulated host/cancer balance among several important cancer preventative signaling mechanisms, leading to hyperglycemia and hyperinsulinemia in the host and runaway aerobic glycolysis, lipid signaling and proliferative activity in the tumor.

Notch pathway signaling in the skin antagonizes Merkel cell development.

PubMed

Logan, Gregory J; Wright, Margaret C; Kubicki, Adam C; Maricich, Stephen M

2018-02-15

Merkel cells are mechanosensitive skin cells derived from the epidermal lineage whose development requires expression of the basic helix-loop-helix transcription factor Atoh1. The genes and pathways involved in regulating Merkel cell development during embryogenesis are poorly understood. Notch pathway signaling antagonizes Atoh1 expression in many developing body regions, so we hypothesized that Notch signaling might inhibit Merkel cell development. We found that conditional, constitutive overexpression of the Notch intracellular domain (NICD) in mouse epidermis significantly decreased Merkel cell numbers in whisker follicles and touch domes of hairy skin. Conversely, conditional deletion of the obligate NICD binding partner RBPj in the epidermis significantly increased Merkel cell numbers in whisker follicles, led to the development of ectopic Merkel cells outside of touch domes in hairy skin epidermis, and altered the distribution of Merkel cells in touch domes. Deletion of the downstream Notch effector gene Hes1 also significantly increased Merkel cell numbers in whisker follicles. Together, these data demonstrate that Notch signaling regulates Merkel cell production and patterning. Copyright © 2018 Elsevier Inc. All rights reserved.

G protein-coupled receptor 56 regulates mechanical overload-induced muscle hypertrophy

PubMed Central

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.

2014-01-01

Peroxisome proliferator-activated receptor gamma coactivator 1-alpha 4 (PGC-1α4) is a protein isoform derived by alternative splicing of the PGC1α 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-1α4 and is induced in humans by resistance exercise. Furthermore, the anabolic effects of PGC-1α4 in cultured murine muscle cells are dependent on GPR56 signaling, because knockdown of GPR56 attenuates PGC-1α4–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 Gα12/13 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

LeERF-1, a novel AP2/ERF family gene within the B3 subcluster, is down-regulated by light signals in Lithospermum erythrorhizon.

PubMed

Zhang, W; Zou, A; Miao, J; Yin, Y; Tian, R; Pang, Y; Yang, R; Qi, J; Yang, Y

2011-03-01

We previously showed that ethylene might be involved in the process of shikonin biosynthesis regulated by light signals. Here, we cloned a full-length cDNA of LeERF-1, a putative ethylene response factor gene, from Lithospermum erythrorhizon using the RACE (rapid amplification of cDNA ends) method. Phylogenetic analysis revealed that LeERF-1 was classified in the B3 subfamily, together with ERF1 and ORA59 of Arabidopsis. Heterologous expression of LeERF-1 in Arabidopsis showed that LeERF-1:eGFP fusion protein was precisely localised to the nucleus, implying that it might function as a transcription factor. Detailed expression analysis with real-time PCR showed that LeERF-1 was significantly down-regulated by white, blue and red light, although the inhibitory effect of red light was relatively weak compared to other light conditions. Tissue-specific expression analysis also indicated that LeERF-1 was dominantly expressed in the roots, which grow in soil in darkness. These patterns are all consistent with the effects of different light signals on regulating formation of shikonin and its derivatives, indicating that LeERF-1 might be a crucial positive regulator, like other B3 subfamily proteins (such as ORCA3 and ORA59), in regulating biosynthesis of secondary metabolites. © 2010 German Botanical Society and The Royal Botanical Society of the Netherlands.

Abscisic acid (ABA) and key proteins in its perception and signaling pathways are ancient, but their roles have changed through time.

PubMed

Sussmilch, Frances C; Atallah, Nadia M; Brodribb, Timothy J; Banks, Jo Ann; McAdam, Scott A M

2017-09-02

Homologs of the Arabidopsis core abscisic acid (ABA) signaling component OPEN STOMATA1 (OST1) are best known for their role in closing stomata in angiosperm species. We recently characterized a fern OST1 homolog, GAMETOPHYTES ABA INSENSITIVE ON ANTHERDIOGEN 1 (GAIA1), which is not required for stomatal closure in ferns, consistent with physiologic evidence that shows the stomata of these plants respond passively to changes in leaf water status. Instead, gaia1 mutants reveal a critical role in ABA signaling for spore dormancy and sex determination, in a system regulated by antagonism between ABA and the gibberellin (GA)-derived fern hormone antheridiogen (A CE ). ABA and key proteins, including ABA receptors from the PYR/PYL/RCAR family and negative regulators of ABA-signaling from Group A of the type-2C protein phosphatases (PP2Cs), in addition to OST1 homologs, can be found in all terrestrial land plant lineages, ranging from liverworts that lack stomata, to angiosperms. As land plants have evolved and diversified over the past 450 million years, so too have the roles of this important plant hormone and the genes involved in its signaling and perception.

Hedgehog Signaling Regulates Epithelial-Mesenchymal Transition in Pancreatic Cancer Stem-Like Cells

PubMed Central

Wang, Feng; Ma, Ling; Zhang, Zhengkui; Liu, Xiaoran; Gao, Hongqiao; Zhuang, Yan; Yang, Pei; Kornmann, Marko; Tian, Xiaodong; Yang, Yinmo

2016-01-01

Hedgehog (Hh) signaling is crucially involved in tumorigenesis. This study aimed to assess the role of Hh signaling in the regulation of epithelial-mesenchymal transition (EMT), stemness properties and chemoresistance of human pancreatic Panc-1 cancer stem cells (CSCs). Panc-1 cells were transfected with recombinant lentiviral vectors to silence SMO and serum-free floating-culture system was used to isolate Panc-1 tumorspheres. The expression of CSC and EMT markers was detected by flow cytometry, real-time RT-PCR and Western blot analysis. Malignant behaviors of Panc-1 CSC were evaluated by tumorigenicity assays and nude mouse lung metastasis model. We found that tumorspheres derived from pancreatic cancer cell line Panc-1 possessed self-renewal, differentiation and stemness properties. Hh pathway and EMT were active in Panc-1 tumorspheres. Inhibition of Hh signaling by SMO knockdown inhibited self-renewal, EMT, invasion, chemoresistance, pulmonary metastasis, tumorigenesis of pancreatic CSCs. In conclusion, Hh signaling contributes to the maintenance of stem-like properties and chemoresistance of pancreatic CSC and promotes the tumorigenesis and metastasis of pancreatic cancer. Hh pathway is a potential molecular target for the development of therapeutic strategies for pancreatic CSCs. PMID:26918054

Epithelial control of gut-associated lymphoid tissue formation through p38α-dependent restraint of NF-κB signaling

PubMed Central

Caballero-Franco, Celia; Guma, Monica; Choo, Min-Kyung; Sano, Yasuyo; Enzler, Thomas; Karin, Michael; Mizoguchi, Atsushi; Park, Jin Mo

2015-01-01

The protein kinase p38α mediates cellular responses to environmental and endogenous cues that direct tissue homeostasis and immune responses. Studies of mice lacking p38α in several different cell types have demonstrated that p38α signaling is essential to maintaining the proliferation-differentiation balance in developing and steady-state tissues. The mechanisms underlying these roles involve cell-autonomous control of signaling and gene expression by p38α. Here we show that p38α regulates gut-associated lymphoid tissue (GALT) formation in a non-cell-autonomous manner. From an investigation of mice with intestinal epithelial cell-specific deletion of the p38α gene, we find that p38α serves to limit NF-κB signaling and thereby attenuate GALT-promoting chemokine expression in the intestinal epithelium. Loss of this regulation results in GALT hyperplasia and, in some animals, mucosa-associated B cell lymphoma. These anomalies occur independently of luminal microbial stimuli and are likely driven by direct epithelial-lymphoid interactions. Our study illustrates a novel p38α-dependent mechanism preventing excessive generation of epithelial-derived signals that drive lymphoid tissue overgrowth and malignancy. PMID:26792803

Control of brain development and homeostasis by local and systemic insulin signalling.

PubMed

Liu, J; Spéder, P; Brand, A H

2014-09-01

Insulin and insulin-like growth factors (IGFs) are important regulators of growth and metabolism. In both vertebrates and invertebrates, insulin/IGFs are made available to various organs, including the brain, through two routes: the circulating systemic insulin/IGFs act on distant organs via endocrine signalling, whereas insulin/IGF ligands released by local tissues act in a paracrine or autocrine fashion. Although the mechanisms governing the secretion and action of systemic insulin/IGF have been the focus of extensive investigation, the significance of locally derived insulin/IGF has only more recently come to the fore. Local insulin/IGF signalling is particularly important for the development and homeostasis of the central nervous system, which is insulated from the systemic environment by the blood-brain barrier. Local insulin/IGF signalling from glial cells, the blood-brain barrier and the cerebrospinal fluid has emerged as a potent regulator of neurogenesis. This review will address the main sources of local insulin/IGF and how they affect neurogenesis during development. In addition, we describe how local insulin/IGF signalling couples neural stem cell proliferation with systemic energy state in Drosophila and in mammals. © 2014 John Wiley & Sons Ltd.

Hedgehog Signaling Regulates Epithelial-Mesenchymal Transition in Pancreatic Cancer Stem-Like Cells.

PubMed

Wang, Feng; Ma, Ling; Zhang, Zhengkui; Liu, Xiaoran; Gao, Hongqiao; Zhuang, Yan; Yang, Pei; Kornmann, Marko; Tian, Xiaodong; Yang, Yinmo

2016-01-01

Hedgehog (Hh) signaling is crucially involved in tumorigenesis. This study aimed to assess the role of Hh signaling in the regulation of epithelial-mesenchymal transition (EMT), stemness properties and chemoresistance of human pancreatic Panc-1 cancer stem cells (CSCs). Panc-1 cells were transfected with recombinant lentiviral vectors to silence SMO and serum-free floating-culture system was used to isolate Panc-1 tumorspheres. The expression of CSC and EMT markers was detected by flow cytometry, real-time RT-PCR and Western blot analysis. Malignant behaviors of Panc-1 CSC were evaluated by tumorigenicity assays and nude mouse lung metastasis model. We found that tumorspheres derived from pancreatic cancer cell line Panc-1 possessed self-renewal, differentiation and stemness properties. Hh pathway and EMT were active in Panc-1 tumorspheres. Inhibition of Hh signaling by SMO knockdown inhibited self-renewal, EMT, invasion, chemoresistance, pulmonary metastasis, tumorigenesis of pancreatic CSCs. In conclusion, Hh signaling contributes to the maintenance of stem-like properties and chemoresistance of pancreatic CSC and promotes the tumorigenesis and metastasis of pancreatic cancer. Hh pathway is a potential molecular target for the development of therapeutic strategies for pancreatic CSCs.

Genome-wide identification of jasmonate biosynthetic genes and their characterization of their expression profiles during apple (Malus x domestica) fruit maturation

USDA-ARS?s Scientific Manuscript database

The plant hormones regulate many physiological processes including apple fruit ripening by integrating diverse developmental cues and environmental signals. In addition to the well-characterized role of ethylene, jasmonic acid (JA) and its derivatives have also been suggested to play an important ro...

Subverting sterols: rerouting an oxysterol-signaling pathway to promote tumor growth

PubMed Central

York, Autumn G.

2013-01-01

Oxysterols are oxidized derivatives of cholesterol that are generated enzymatically or through autoxidation. Initially identified as important lipid signaling molecules in the context of atherosclerosis and inflammation, accumulated evidence indicates that these lipid-signaling molecules can have pleiotropic effects on the fate and function of the immune system. These effects range from the regulation of immune cell survival and proliferation to chemotaxis and antiviral immunity. New studies now indicate that tumor-derived oxysterols can serve to subvert the immune system by recruiting protumorigenic neutrophils into the tumor microenvironment. The consequence of this recruitment is the generation of proangiogenic factors and matrix metalloproteinase proteins that provide a tumor a significant growth and survival advantage. In combination with other recent studies, these data highlight the ongoing cross talk between sterol metabolism and the immune system, and they raise the intriguing possibility that targeting oxysterol pathways could serve as a novel therapeutic approach in the war on cancer. PMID:23980123

Gut vagal sensory signaling regulates hippocampus function through multi-order pathways.

PubMed

Suarez, Andrea N; Hsu, Ted M; Liu, Clarissa M; Noble, Emily E; Cortella, Alyssa M; Nakamoto, Emily M; Hahn, Joel D; de Lartigue, Guillaume; Kanoski, Scott E

2018-06-05

The vagus nerve is the primary means of neural communication between the gastrointestinal (GI) tract and the brain. Vagally mediated GI signals activate the hippocampus (HPC), a brain region classically linked with memory function. However, the endogenous relevance of GI-derived vagal HPC communication is unknown. Here we utilize a saporin (SAP)-based lesioning procedure to reveal that selective GI vagal sensory/afferent ablation in rats impairs HPC-dependent episodic and spatial memory, effects associated with reduced HPC neurotrophic and neurogenesis markers. To determine the neural pathways connecting the gut to the HPC, we utilize monosynaptic and multisynaptic virus-based tracing methods to identify the medial septum as a relay connecting the medial nucleus tractus solitarius (where GI vagal afferents synapse) to dorsal HPC glutamatergic neurons. We conclude that endogenous GI-derived vagal sensory signaling promotes HPC-dependent memory function via a multi-order brainstem-septal pathway, thereby identifying a previously unknown role for the gut-brain axis in memory control.

Free radicals mediate systemic acquired resistance.

PubMed

Wang, Caixia; El-Shetehy, Mohamed; Shine, M B; Yu, Keshun; Navarre, Duroy; Wendehenne, David; Kachroo, Aardra; Kachroo, Pradeep

2014-04-24

Systemic acquired resistance (SAR) is a form of resistance that protects plants against a broad spectrum of secondary infections. However, exploiting SAR for the protection of agriculturally important plants warrants a thorough investigation of the mutual interrelationships among the various signals that mediate SAR. Here, we show that nitric oxide (NO) and reactive oxygen species (ROS) serve as inducers of SAR in a concentration-dependent manner. Thus, genetic mutations that either inhibit NO/ROS production or increase NO accumulation (e.g., a mutation in S-nitrosoglutathione reductase [GSNOR]) abrogate SAR. Different ROS function additively to generate the fatty-acid-derived azelaic acid (AzA), which in turn induces production of the SAR inducer glycerol-3-phosphate (G3P). Notably, this NO/ROS→AzA→G3P-induced signaling functions in parallel with salicylic acid-derived signaling. We propose that the parallel operation of NO/ROS and SA pathways facilitates coordinated regulation in order to ensure optimal induction of SAR. Copyright © 2014 The Authors. Published by Elsevier Inc. All rights reserved.

The platelet-derived growth factor receptor/STAT3 signaling pathway regulates the phenotypic transition of corpus cavernosum smooth muscle in rats.

PubMed

Yan, Jun-Feng; Huang, Wen-Jie; Zhao, Jian-Feng; Fu, Hui-Ying; Zhang, Gao-Yue; Huang, Xiao-Jun; Lv, Bo-Dong

2017-01-01

Erectile dysfunction (ED) is a common clinical disease that is difficult to treat. We previously found that hypoxia modulates the phenotype of primary corpus cavernosum smooth muscle cells (CCSMCs) in rats, but the underlying molecular mechanism is still unknown. Platelet-derived growth factor receptor (PDGFR)-related signaling pathways are correlated with cell phenotypic transition, but research has been focused more on vascular smooth muscle and tracheal smooth muscle and less on CCSMCs. Here, we investigated the role of PDGFR-related signaling pathways in penile CCSMCs, which were successfully isolated from rats and cultured in vitro. PDGF-BB at 5, 10, or 20 ng/ml altered CCSMC morphology from the original elongated, spindle shape to a broader shape and promoted the synthetic phenotype and expression of the related proteins vimentin and collagen-I, while inhibiting the contractile phenotype and expression of the related proteins smooth muscle (SM) α-actin (α-SMA) and desmin. Inhibition of PDGFR activity via siRNA or the PDGFR inhibitor crenolanib inhibited vimentin and collagen-I expression, increased α-SMA and desmin expression, and considerably inhibited serine-threonine protein kinase (AKT) and signal transducer and activator of transcription 3 (STAT3) phosphorylation. STAT3 knockdown promoted the contractile phenotype, inhibited vimentin and collagen-I expression, and increased α-SMA and desmin expression, whereas AKT knockdown did not affect phenotype-associated proteins. STAT3 overexpression in CCSMC cells weakened the suppressive effect of PDGFR inhibition on the morphology and phenotypic transformation induced by PDGF-BB. Through activation of the PDGFR/STAT3 signaling pathway, PDGF promoted the synthetic phenotype transition; thus, regulation of this pathway might contribute to ED therapy.

CHP1002, a novel andrographolide derivative, inhibits pro-inflammatory inducible nitric oxide synthase and cyclooxygenase-2 expressions in RAW264.7 macrophages via up-regulation of heme oxygenase-1 expression.

PubMed

Zhang, Bo; Yan, Lingdi; Zhou, Peilan; Dong, Zhaoqi; Feng, Siliang; Liu, Keliang; Gong, Zehui

2013-02-01

Andrographolides, a type of diterpene lactone, are widely known to have anti-inflammatory and anti-oxidative properties. CHP1002, a synthetic derivative of andrographolide, has similar anti-inflammatory action in mouse ear swelling test and rat paw edema test. In the present study, the mechanism of anti-inflammatory effects of CHP1002 was investigated in RAW264.7 macrophages. CHP1002 potently suppressed inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) expressions in lipopolysaccharide (LPS)-stimulated RAW264.7 macrophages. CHP1002 reduced the production of iNOS-derived nitric oxide (NO) and COX-2-derived prostaglandin E2 (PGE2). CHP1002 induced heme oxygenase-1 (HO-1) expression via activation of extracellular signal-regulated kinase (ERK) and NF-E2 related factor 2 transcription factor (Nrf2). Down-regulation of LPS-induced iNOS and COX-2 expressions was partially reversed by the HO-1 inhibitor zinc protoporphyrin (ZnPP). In addition, CHP1002 significantly attenuated LPS-induced TNF-α, IL-1β and IL-6 production. CHP1002 effectively induced HO-1 and was capable of inhibiting some macrophage-derived pro-inflammatory mediators, which may be closely correlated with its anti-inflammatory action. Copyright © 2012 Elsevier B.V. All rights reserved.

The Nuclear Receptor AhR Controls Bone Homeostasis by Regulating Osteoclast Differentiation via the RANK/c-Fos Signaling Axis.

PubMed

Izawa, Takashi; Arakaki, Rieko; Mori, Hiroki; Tsunematsu, Takaaki; Kudo, Yasusei; Tanaka, Eiji; Ishimaru, Naozumi

2016-12-15

The aryl hydrocarbon receptor (AhR) pathway plays a key role in receptor activator of NF-κB ligand (RANKL)-mediated osteoclastogenesis. However, the mechanism underlying the regulation of AhR expression in osteoclasts and the signaling pathway through which AhR controls osteoclastogenesis remain unclear. We found that the expression of AhR in bone marrow-derived osteoclasts was upregulated by RANKL at an earlier stage than was the expression of signature osteoclast genes such as those encoding cathepsin K and NFAT, cytoplasmic, calcineurin-dependent 1. In response to RANKL, bone marrow macrophages isolated from AhR -/- mice exhibited impaired phosphorylation of Akt and MAPK as well as NF-κB, whereas their response to M-CSF remained unchanged. Osteoclast differentiation mediated by the AhR signaling pathway was also regulated in an RANKL/c-Fos-dependent manner. Furthermore, ligand activation of AhR by the smoke toxin benzo[a]pyrene accelerated osteoclast differentiation in a receptor-dependent manner, and AhR-dependent regulation of mitochondrial biogenesis in osteoclasts was observed. Moreover, AhR -/- mice exhibited impaired bone healing with delayed endochondral ossification. Taken together, the present results suggest that the RANKL/AhR/c-Fos signaling axis plays a critical role in osteoclastogenesis, thereby identifying the potential of AhR in treating pathological, inflammatory, or metabolic disorders of the bone. Copyright © 2016 by The American Association of Immunologists, Inc.

Nitric Oxide Analyzer Quantification of Plant S-Nitrosothiols.

PubMed

Hussain, Adil; Yun, Byung-Wook; Loake, Gary J

2018-01-01

Nitric oxide (NO) is a small diatomic molecule that regulates multiple physiological processes in animals, plants, and microorganisms. In animals, it is involved in vasodilation and neurotransmission and is present in exhaled breath. In plants, it regulates both plant immune function and numerous developmental programs. The high reactivity and short half-life of NO and cross-reactivity of its various derivatives make its quantification difficult. Different methods based on calorimetric, fluorometric, and chemiluminescent detection of NO and its derivatives are available, but all of them have significant limitations. Here we describe a method for the chemiluminescence-based quantification of NO using ozone-chemiluminescence technology in plants. This approach provides a sensitive, robust, and flexible approach for determining the levels of NO and its signaling products, protein S-nitrosothiols.

Brain-derived neurotrophic factor in the nucleus tractus solitarii modulates glucose homeostasis after carotid chemoreceptor stimulation in rats.

PubMed

Montero, Sergio; Cuéllar, Ricardo; Lemus, Mónica; Avalos, Reyes; Ramírez, Gladys; de Álvarez-Buylla, Elena Roces

2012-01-01

Neuronal systems, which regulate energy intake, energy expenditure and endogenous glucose production, sense and respond to input from hormonal related signals that convey information from body energy availability. Carotid chemoreceptors (CChr) function as sensors for circulating glucose levels and contribute to glycemic counterregulatory responses. Brain-derived neurotrophic factor (BDNF) that plays an important role in the endocrine system to regulate glucose metabolism could play a role in hyperglycemic glucose reflex with brain glucose retention (BGR) evoked by anoxic CChr stimulation. Infusing BDNF into the nucleus tractus solitarii (NTS) before CChr stimulation, showed that this neurotrophin increased arterial glucose and BGR. In contrast, BDNF receptor (TrkB) antagonist (K252a) infusions in NTS resulted in a decrease in both glucose variables.

Targeting progesterone metabolism in breast cancer with l-proline derived new 14-azasteroids.

PubMed

Singh, Jyotsana; Singh, Ritesh; Gupta, Preeti; Rai, Smita; Ganesher, Asha; Badrinarayan, Preethi; Sastry, G Narahari; Konwar, Rituraj; Panda, Gautam

2017-08-15

Breast cancer cell proliferation is promoted by a variety of mitogenic signals. Classically estrogen is considered as most predominant mitogenic signal in hormone-dependent breast cancer and progesterone is primarily considered to have protective effect. However, it is suggested that some progesterone metabolite may promote breast cancer and progesterone metabolites like 5α-pregnane and 4-pregnene could serve as regulators of estrogen-responsiveness of breast cancer cells. Here, we estimated the potential of alternate targeting of breast cancer via progesterone signalling. l-Proline derived novel 14-azasteroid compounds were screened against MCF-7 and MDA-MB-231 cell lines using MTT assay. In silico studies, cell cycle, Annexin-V-FITC/PI, JC-1 mitochondrial assay, ROS analysis were performed to analyse the impact of hit compound 3b on breast cancer cells. Further, we analysed the impact of hit 3b on the progesterone, its metabolites and enzymes responsible for the conversion of progesterone and its metabolites using ELISA. Data suggests that compound 3b binds and down regulates of 5α-reductase by specifically inhibiting production of progesterone metabolites that are capable of promoting breast cancer proliferation, epithelial mesenchymal transition and migration. This study establishes the proof of concept and generation of new leads for additional targeting of breast cancer. Copyright © 2017 Elsevier Ltd. All rights reserved.

Brain-derived neurotrophic factor and its clinical implications

PubMed Central

Bathina, Siresha

2015-01-01

Brain-derived neurotrophic factor (BDNF) plays an important role in neuronal survival and growth, serves as a neurotransmitter modulator, and participates in neuronal plasticity, which is essential for learning and memory. It is widely expressed in the CNS, gut and other tissues. BDNF binds to its high affinity receptor TrkB (tyrosine kinase B) and activates signal transduction cascades (IRS1/2, PI3K, Akt), crucial for CREB and CBP production, that encode proteins involved in β cell survival. BDNF and insulin-like growth factor-1 have similar downstream signaling mechanisms incorporating both p-CAMK and MAPK that increase the expression of pro-survival genes. Brain-derived neurotrophic factor regulates glucose and energy metabolism and prevents exhaustion of β cells. Decreased levels of BDNF are associated with neurodegenerative diseases with neuronal loss, such as Parkinson's disease, Alzheimer's disease, multiple sclerosis and Huntington's disease. Thus, BDNF may be useful in the prevention and management of several diseases including diabetes mellitus. PMID:26788077

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

Zhang, Ling; Gan, Xueqi; Zhu, Zhuoli

Although many previous studies have shown that refractory period-dependent memory effect of vibration stress is anabolic for skeletal homeostasis, little is known about the rapid response of osteoblasts simply derived from vibration itself. In view of the potential role of reactive oxygen species (ROS) in mediating differentiated activity of osteoblasts, whether and how ROS regulates the rapid effect of vibration deserve to be demonstrated. Our findings indicated that MC3T3-E1 cells underwent decreased gene expression of Runx2, Col-I and ALP and impaired ALP activity accompanied by increased mitochondrial fission immediately after vibration loading. Moreover, we also revealed the involvement of ERK-Drp1more » signal transduction in ROS regulatory mechanisms responsible for the rapid effect of vibration stress. - Highlights: • ROS contributed to the rapid response of MC3T3-E1 cells for vibration stress. • Imbalance of mitochondrial dynamics were linked to the LMHFV-derived rapid response. • The role of ERK-Drp1 signal pathway in the LMHFV-derived osteoblast rapid response.« less

Sol-gel derived lithium-releasing glass for cartilage regeneration.

PubMed

Li, Siwei; Maçon, Anthony L B; Jacquemin, Manon; Stevens, Molly M; Jones, Julian R

2017-07-01

Wnt-signalling cascade is one of the crucial pathways involved in the development and homeostasis of cartilage. Influencing this pathway can potentially contribute to improved cartilage repair or regeneration. One key molecular regulator of the Wnt pathway is the glycogen synthase kinase-3 enzyme, the inhibition of which allows initiation of the signalling pathway. This study aims to utilise a binary SiO 2 -Li 2 O sol-gel derived glass for controlled delivery of lithium, a known glycogen synthase kinase-3 antagonist. The effect of the dissolution products of the glass on chondrogenic differentiation in an in vitro 3D pellet culture model is reported. Dissolution products that contained 5 mM lithium and 3.5 mM silicon were capable of inducing chondrogenic differentiation and hyaline cartilaginous matrix formation without the presence of growth factors such as TGF-β3. The results suggest that sol-gel derived glass has the potential to be used as a delivery vehicle for therapeutic lithium ions in cartilage regeneration applications.

Adaptive Responses of Neuronal Mitochondria to Bioenergetic Challenges: Roles in Neuroplasticity and Disease Resistance

PubMed Central

Raefsky, Sophia M.; Mattson, Mark P.

2016-01-01

An important concept in neurobiology is “neurons that fire together, wire together” which means that the formation and maintenance of synapses is promoted by activation of those synapses. Very similar to the effects of the stress of exercise on muscle cells, emerging findings suggest that neurons respond to activity by activating signaling pathways (e.g., Ca2+, CREB, PGC-1α, NF-κB) that stimulate mitochondrial biogenesis and cellular stress resistance. These pathways are also activated by aerobic exercise and food deprivation, two bioenergetic challenges of fundamental importance in the evolution of the brains of all mammals, including humans. The metabolic ‘switch’ in fuel source from liver glycogen store-derived glucose to adipose cell-derived fatty acids and their ketone metabolites during fasting and sustained exercise, appears to be a pivotal trigger of both brain-intrinsic and peripheral organ-derived signals that enhance learning and memory and underlying synaptic plasticity and neurogenesis. Brain-intrinsic extracellular signals include the excitatory neurotransmitter glutamate and the neurotrophic factor BDNF, and peripheral signals may include the liver-derived ketone 3-hydroxybutyrate and the muscle cell-derived protein irisin. Emerging findings suggest that fasting, exercise and an intellectually challenging lifestyle can protect neurons against the dysfunction and degeneration that they would otherwise suffer in acute brain injuries (stroke and head trauma) and neurodegenerative disorders including Alzheimer’s, Parkinson’s and Huntington’s disease. Among the prominent intracellular responses of neurons to these bioenergetic challenges are up-regulation of antioxidant defenses, autophagy/mitophagy and DNA repair. A better understanding of such fundamental hormesis-based adaptive neuronal response mechanisms is expected to result in the development and implementation of novel interventions to promote optimal brain function and healthy brain aging. PMID:27908782

The Importance of NADPH Oxidases and Redox Signaling in Angiogenesis

PubMed Central

Prieto-Bermejo, Rodrigo; Hernández-Hernández, Angel

2017-01-01

Eukaryotic cells have to cope with the constant generation of reactive oxygen species (ROS). Although the excessive production of ROS might be deleterious for cell biology, there is a plethora of evidence showing that moderate levels of ROS are important for the control of cell signaling and gene expression. The family of the nicotinamide adenine dinucleotide phosphate oxidases (NADPH oxidases or Nox) has evolved to produce ROS in response to different signals; therefore, they fulfil a central role in the control of redox signaling. The role of NADPH oxidases in vascular physiology has been a field of intense study over the last two decades. In this review we will briefly analyze how ROS can regulate signaling and gene expression. We will address the implication of NADPH oxidases and redox signaling in angiogenesis, and finally, the therapeutic possibilities derived from this knowledge will be discussed. PMID:28505091

An Fgf-Shh signaling hierarchy regulates early specification of the zebrafish skull

PubMed Central

McCarthy, Neil; Sidik, Alfire; Bertrand, Julien Y.; Eberhart, Johann K.

2016-01-01

The neurocranium generates most of the craniofacial skeleton and consists of prechordal and postchordal regions. Although development of the prechordal is well studied, little is known of the postchordal region. Here we characterize a signaling hierarchy necessary for postchordal neurocranial development involving Fibroblast growth factor (Fgf) signaling for early specification of mesodermally-derived progenitor cells. The expression of hyaluron synthetase 2 (has2) in the cephalic mesoderm requires Fgf signaling and Has2 function, in turn, is required for postchordal neurocranial development. While Hedgehog (Hh)-deficient embryos also lack a postchordal neurocranium, this appears primarily due to a later defect in chondrocyte differentiation. Inhibitor studies demonstrate that postchordal neurocranial development requires early Fgf and later Hh signaling. Collectively, our results provide a mechanistic understanding of early postchordal neurocranial development and demonstrate a hierarchy of signaling between Fgf and Hh in the development of this structure. PMID:27060628

A novel mode of regulation of the Staphylococcus aureus Vancomycin-resistance-associated response regulator VraR mediated by Stk1 protein phosphorylation.

PubMed

Canova, Marc J; Baronian, Grégory; Brelle, Solène; Cohen-Gonsaud, Martin; Bischoff, Markus; Molle, Virginie

2014-04-25

The Staphylococcus aureus Vancomycin-resistance-associated response regulator VraR is known as an important response regulator, member of the VraTSR three-component signal transduction system that modulates the expression of the cell wall stress stimulon in response to a number of different cell wall active antibiotics. Given its crucial role in regulating gene expression in response to antibiotic challenges, VraR must be tightly regulated. We report here for the first time in S. aureus convergence of two major signal transduction systems, serine/threonine protein kinase and two (three)-component systems. We demonstrate that VraR can be phosphorylated by the staphylococcal Ser/Thr protein kinase Stk1 and that phosphorylation negatively affects its DNA-binding properties. Mass spectrometric analyses and site-directed mutagenesis identified Thr106, Thr119, Thr175 and Thr178 as phosphoacceptors. A S. aureus ΔvraR mutant expressing a VraR derivative that mimics constitutive phosphorylation, VraR_Asp, still exhibited markedly decreased antibiotic resistance against different cell wall active antibiotics, when compared to the wild-type, suggesting that VraR phosphorylation may represent a novel and presumably more general mechanism of regulation of the two (three)-component systems in staphylococci. Copyright © 2014 Elsevier Inc. All rights reserved.

Biological Characteristics and Genetic Heterogeneity between Carcinoma-Associated Fibroblasts and Their Paired Normal Fibroblasts in Human Breast Cancer

PubMed Central

Hou, Yixuan; Sun, Yan; Wang, Liyang; Luo, Haojun; Peng, Huimin; Liu, Manran

2013-01-01

Background The extensional signals in cross-talk between stromal cells and tumor cells generated from extracellular matrix molecules, soluble factor, and cell-cell adhesion complexes cooperate at the extra- and intracellular level in the tumor microenvironment. CAFs are the primary type of stromal cells in the tumor microenvironment and play a pivotal role in tumorigenesis and development. Hitherto, there is hardly any systematic analysis of the intrinsic relationship between CAFs function and its abnormal signaling pathway. The extreme complexity of CAFs’ features and their role in tumor development are needed to be further investigated. Methodology/Principal Findings We primary cultured CAFs and NFs from early stages of breast cancer tissue and identified them using their biomarker by immunohistochemistry for Fibronectin, α-SMA and FAP. Microarray was applied to analyze gene expression profiles of human breast CAFs and the paired NFs. The Up-regulated genes classified by Gene Ontology, signal pathways enriched by DAVID pathway analysis. Abnormal signaling pathways in breast cancer CAFs are involved in cell cycle, cell adhesion, signal transduction and protein transport being reported in CAFs derived from other tumors. Significantly, the altered ATM signaling pathway, a set of cell cycle regulated signaling, and immune associated signaling are identified to be changed in CAFs. Conclusions/Significance CAFs have the vigorous ability of proliferation and potential of invasion and migration comparing with NFs. CAFs could promote breast cancer cell invasion under co-culture conditions through up-regulated CCL18 and CXCL12. Consistently with its biologic behavior, the gene expression profiling analyzed by microarray shows that some of key signaling pathways, such as cell cycle, cell adhesion, and secreting factors play an important role in CAFs. The altered ATM signaling pathway is abnormally active in the early stage of breast cancer. The set of immune associated signaling may be involved in tumor cell immune evasion. PMID:23577100

Insulin resistance, glycemic control and adiposity: key determinants of healthy lifespan.

PubMed

DiStefano, Peter S; Curtis, Rory; Geddes, Bradley J

2007-04-01

Identification of genes and pathways that alter lifespan has allowed for new insights into factors that control the aging process as well as disease. While strong molecular links exist between aging and metabolism, we hypothesize that targeting the mechanisms involved in aging will also give rise to therapeutics that treat other devastating age-related diseases, such as neurodegeneration, cancer, inflammation and cardiovascular disease. Insulin sensitivity, glycemic control and adiposity are not only hallmarks of the major metabolic diseases, type 2 diabetes and obesity, but they also represent significant risk factors for the development of Alzheimer's Disease and cognitive impairment. Insulin/IGF-1 signaling is an important pathway regulating aging and disease in a variety of species, including mammals. Here we describe an important role for the gut-derived peptide ghrelin in upstream signaling through the insulin/IGF-1 pathway and exemplify modulation of ghrelin signaling as an approach to mechanistic treatment of multiple age-related diseases by virtue of its ability to regulate key metabolic functions.

S-nitrosothiols regulate nitric oxide production and storage in plants through the nitrogen assimilation pathway

PubMed Central

Frungillo, Lucas; Skelly, Michael J.; Loake, Gary J.; Spoel, Steven H.; Salgado, Ione

2014-01-01

Nitrogen assimilation plays a vital role in plant metabolism. Assimilation of nitrate, the primary source of nitrogen in soil, is linked to generation of the redox signal nitric oxide (NO). An important mechanism by which NO regulates plant development and stress responses is through S-nitrosylation, i.e. covalent attachment of NO to cysteines to form S-nitrosothiols (SNO). Despite the importance of nitrogen assimilation and NO signalling, it remains largely unknown how these pathways are interconnected. Here we show that SNO signalling suppresses both nitrate uptake and reduction by transporters and reductases, respectively, to fine-tune nitrate homeostasis. Moreover, NO derived from nitrate assimilation suppresses the redox enzyme S-nitrosoglutathione Reductase 1 (GSNOR1) by S-nitrosylation, preventing scavenging of S-nitrosoglutathione, a major cellular bio-reservoir of NO. Hence, our data demonstrates that (S)NO controls its own generation and scavenging by modulating nitrate assimilation and GSNOR1 activity. PMID:25384398

Knowing your friends and foes--plant receptor-like kinases as initiators of symbiosis or defence.

PubMed

Antolín-Llovera, Meritxell; Petutsching, Elena Kristin; Ried, Martina Katharina; Lipka, Volker; Nürnberger, Thorsten; Robatzek, Silke; Parniske, Martin

2014-12-01

The decision between defence and symbiosis signalling in plants involves alternative and modular plasma membrane-localized receptor complexes. A critical step in their activation is ligand-induced homo- or hetero-oligomerization of leucine-rich repeat (LRR)- and/or lysin motif (LysM) receptor-like kinases (RLKs). In defence signalling, receptor complexes form upon binding of pathogen-associated molecular patterns (PAMPs), including the bacterial flagellin-derived peptide flg22, or chitin. Similar mechanisms are likely to operate during the perception of microbial symbiont-derived (lipo)-chitooligosaccharides. The structurally related chitin-oligomer ligands chitooctaose and chitotetraose trigger defence and symbiosis signalling, respectively, and their discrimination involves closely related, if not identical, LysM-RLKs. This illustrates the demand for and the challenges imposed on decision mechanisms that ensure appropriate signal initiation. Appropriate signalling critically depends on abundance and localization of RLKs at the cell surface. This is regulated by internalization, which also provides a mechanism for the removal of activated signalling RLKs. Abundance of the malectin-like domain (MLD)-LRR-RLK Symbiosis Receptor-like Kinase (SYMRK) is additionally controlled by cleavage of its modular ectodomain, which generates a truncated and rapidly degraded RLK fragment. This review explores LRR- and LysM-mediated signalling, the involvement of MLD-LRR-RLKs in symbiosis and defence, and the role of endocytosis in RLK function. © 2014 The Authors. New Phytologist © 2014 New Phytologist Trust.

Hypothalamic circuits regulating appetite and energy homeostasis: pathways to obesity

PubMed Central

Timper, Katharina; Brüning, Jens C.

2017-01-01

ABSTRACT The ‘obesity epidemic’ represents a major global socioeconomic burden that urgently calls for a better understanding of the underlying causes of increased weight gain and its associated metabolic comorbidities, such as type 2 diabetes mellitus and cardiovascular diseases. Improving our understanding of the cellular basis of obesity could set the stage for the development of new therapeutic strategies. The CNS plays a pivotal role in the regulation of energy and glucose homeostasis. Distinct neuronal cell populations, particularly within the arcuate nucleus of the hypothalamus, sense the nutrient status of the organism and integrate signals from peripheral hormones including pancreas-derived insulin and adipocyte-derived leptin to regulate calorie intake, glucose metabolism and energy expenditure. The arcuate neurons are tightly connected to other specialized neuronal subpopulations within the hypothalamus, but also to various extrahypothalamic brain regions, allowing a coordinated behavioral response. This At a Glance article gives an overview of the recent knowledge, mainly derived from rodent models, regarding the CNS-dependent regulation of energy and glucose homeostasis, and illustrates how dysregulation of the neuronal networks involved can lead to overnutrition and obesity. The potential impact of recent research findings in the field on therapeutic treatment strategies for human obesity is also discussed. PMID:28592656

Hypothalamic circuits regulating appetite and energy homeostasis: pathways to obesity.

PubMed

Timper, Katharina; Brüning, Jens C

2017-06-01

The 'obesity epidemic' represents a major global socioeconomic burden that urgently calls for a better understanding of the underlying causes of increased weight gain and its associated metabolic comorbidities, such as type 2 diabetes mellitus and cardiovascular diseases. Improving our understanding of the cellular basis of obesity could set the stage for the development of new therapeutic strategies. The CNS plays a pivotal role in the regulation of energy and glucose homeostasis. Distinct neuronal cell populations, particularly within the arcuate nucleus of the hypothalamus, sense the nutrient status of the organism and integrate signals from peripheral hormones including pancreas-derived insulin and adipocyte-derived leptin to regulate calorie intake, glucose metabolism and energy expenditure. The arcuate neurons are tightly connected to other specialized neuronal subpopulations within the hypothalamus, but also to various extrahypothalamic brain regions, allowing a coordinated behavioral response. This At a Glance article gives an overview of the recent knowledge, mainly derived from rodent models, regarding the CNS-dependent regulation of energy and glucose homeostasis, and illustrates how dysregulation of the neuronal networks involved can lead to overnutrition and obesity. The potential impact of recent research findings in the field on therapeutic treatment strategies for human obesity is also discussed. © 2017. Published by The Company of Biologists Ltd.

Regulation of zinc homeostasis by inducible NO synthase-derived NO: nuclear metallothionein translocation and intranuclear Zn2+ release.

PubMed

Spahl, Daniela U; Berendji-Grün, Denise; Suschek, Christoph V; Kolb-Bachofen, Victoria; Kröncke, Klaus-D

2003-11-25

Zn2+ is critical for the functional and structural integrity of cells and contributes to a number of important processes including gene expression. It has been shown that NO exogenously applied via NO donors resulting in nitrosative stress leads to cytoplasmic Zn2+ release from the zinc storing protein metallothionein (MT) and probably other proteins that complex Zn2+ via cysteine thiols. We show here that, in cytokine-activated murine aortic endothelial cells, NO derived from the inducible NO synthase (iNOS) induces a transient nuclear release of Zn2+. This nuclear Zn2+ release depends on the presence of MT as shown by the lack of this effect in activated endothelial cells from MT-deficient mice and temporally correlates with nuclear MT translocation. Data also show that NO is an essential but not sufficient signal for MT-mediated Zn2+ trafficking from the cytoplasm into the nucleus. In addition, we found that, endogenously via iNOS, synthesized NO increases the constitutive mRNA expression of both MT-1 and MT-2 genes and that nitrosative stress exogenously applied via an NO donor increases constitutive MT mRNA expression via intracellular Zn2+ release. In conclusion, we here provide evidence for a signaling mechanism based on iNOS-derived NO through the regulation of intracellular Zn2+ trafficking and homeostasis.

Regulation of zinc homeostasis by inducible NO synthase-derived NO: Nuclear metallothionein translocation and intranuclear Zn2+ release

PubMed Central

Spahl, Daniela U.; Berendji-Grün, Denise; Suschek, Christoph V.; Kolb-Bachofen, Victoria; Kröncke, Klaus-D.

2003-01-01

Zn2+ is critical for the functional and structural integrity of cells and contributes to a number of important processes including gene expression. It has been shown that NO exogenously applied via NO donors resulting in nitrosative stress leads to cytoplasmic Zn2+ release from the zinc storing protein metallothionein (MT) and probably other proteins that complex Zn2+ via cysteine thiols. We show here that, in cytokine-activated murine aortic endothelial cells, NO derived from the inducible NO synthase (iNOS) induces a transient nuclear release of Zn2+. This nuclear Zn2+ release depends on the presence of MT as shown by the lack of this effect in activated endothelial cells from MT-deficient mice and temporally correlates with nuclear MT translocation. Data also show that NO is an essential but not sufficient signal for MT-mediated Zn2+ trafficking from the cytoplasm into the nucleus. In addition, we found that, endogenously via iNOS, synthesized NO increases the constitutive mRNA expression of both MT-1 and MT-2 genes and that nitrosative stress exogenously applied via an NO donor increases constitutive MT mRNA expression via intracellular Zn2+ release. In conclusion, we here provide evidence for a signaling mechanism based on iNOS-derived NO through the regulation of intracellular Zn2+ trafficking and homeostasis. PMID:14617770

Copine1 regulates neural stem cell functions during brain development.

PubMed

Kim, Tae Hwan; Sung, Soo-Eun; Cheal Yoo, Jae; Park, Jae-Yong; Yi, Gwan-Su; Heo, Jun Young; Lee, Jae-Ran; Kim, Nam-Soon; Lee, Da Yong

2018-01-01

Copine 1 (CPNE1) is a well-known phospholipid binding protein in plasma membrane of various cell types. In brain cells, CPNE1 is closely associated with AKT signaling pathway, which is important for neural stem cell (NSC) functions during brain development. Here, we investigated the role of CPNE1 in the regulation of brain NSC functions during brain development and determined its underlying mechanism. In this study, abundant expression of CPNE1 was observed in neural lineage cells including NSCs and immature neurons in human. With mouse brain tissues in various developmental stages, we found that CPNE1 expression was higher at early embryonic stages compared to postnatal and adult stages. To model developing brain in vitro, we used primary NSCs derived from mouse embryonic hippocampus. Our in vitro study shows decreased proliferation and multi-lineage differentiation potential in CPNE1 deficient NSCs. Finally, we found that the deficiency of CPNE1 downregulated mTOR signaling in embryonic NSCs. These data demonstrate that CPNE1 plays a key role in the regulation of NSC functions through the activation of AKT-mTOR signaling pathway during brain development. Copyright © 2017 Elsevier Inc. All rights reserved.

Epidermal growth factor receptor signaling promotes metastatic prostate cancer through microRNA-96-mediated downregulation of the tumor suppressor ETV6.

PubMed

Tsai, Yuan-Chin; Chen, Wei-Yu; Siu, Man Kit; Tsai, Hong-Yuan; Yin, Juan Juan; Huang, Jiaoti; Liu, Yen-Nien

2017-01-01

It has been suggested that ETV6 serves as a tumor suppressor; however, its molecular regulation and cellular functions remain unclear. We used prostate cancer as a model system and demonstrated a molecular mechanism in which ETV6 can be regulated by epidermal growth factor receptor (EGFR) signaling through microRNA-96 (miR-96)-mediated downregulation. In addition, EGFR acts as a transcriptional coactivator that binds to the promoter of primary miR-96 and transcriptionally regulates miR-96 levels. We analyzed two sets of clinical prostate cancer samples, confirmed association patterns that were consistent with the EGFR-miR-96-ETV6 signaling model and demonstrated that the reduced ETV6 levels were associated with malignant prostate cancer. Based on results derived from multiple approaches, we identified the biological functions of ETV6 as a tumor suppressor that inhibits proliferation and metastasis in prostate cancer. We present a molecular mechanism in which EGFR activation leads to the induction of miR-96 expression and suppression of ETV6, which contributes to prostate cancer progression. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

A microRNA-mRNA expression network during oral siphon regeneration in Ciona.

PubMed

Spina, Elijah J; Guzman, Elmer; Zhou, Hongjun; Kosik, Kenneth S; Smith, William C

2017-05-15

Here we present a parallel study of mRNA and microRNA expression during oral siphon (OS) regeneration in Ciona robusta , and the derived network of their interactions. In the process of identifying 248 mRNAs and 15 microRNAs as differentially expressed, we also identified 57 novel microRNAs, several of which are among the most highly differentially expressed. Analysis of functional categories identified enriched transcripts related to stress responses and apoptosis at the wound healing stage, signaling pathways including Wnt and TGFβ during early regrowth, and negative regulation of extracellular proteases in late stage regeneration. Consistent with the expression results, we found that inhibition of TGFβ signaling blocked OS regeneration. A correlation network was subsequently inferred for all predicted microRNA-mRNA target pairs expressed during regeneration. Network-based clustering associated transcripts into 22 non-overlapping groups, the functional analysis of which showed enrichment of stress response, signaling pathway and extracellular protease categories that could be related to specific microRNAs. Predicted targets of the miR-9 cluster suggest a role in regulating differentiation and the proliferative state of neural progenitors through regulation of the cytoskeleton and cell cycle. © 2017. Published by The Company of Biologists Ltd.

Integrated mixed signal control IC for 500-kHz switching frequency buck regulator

NASA Astrophysics Data System (ADS)

Chen, Keng; Zhang, Hong

2015-12-01

The main purpose for this work is to study the challenges of designing a digital buck regulator using pipelined analog to digital converter (ADC). Although pipelined ADC can achieve high sampling speed, it will introduce additional phase lag to the buck circuit. Along with the latency brought by processing time of additional digital circuits, as well as the time delay associated with the switching frequency, the closed loop will be unstable; moreover, raw ADC outputs have low signal-to-noise ratio, which usually need back-end calibration. In order to compensate these phase lag and make control loop unconditional stable, as well as boost up signal-to-noise ratio of the ADC block with cost-efficient design, a finite impulse response filter followed by digital proportional-integral-derivative blocks were designed. All these digital function blocks were optimised with processing speed. In the system simulation, it can be found that this controller achieved output regulation within 10% of nominal 5 V output voltage under 1 A/µs load transient condition; moreover, with the soft-start method, there is no turn-on overshooting. The die size of this controller is controlled within 3 mm2 by using 180 nm CMOS technology.

Regulation of the Host Antiviral State by Intercellular Communications

PubMed Central

Assil, Sonia; Webster, Brian; Dreux, Marlène

2015-01-01

Viruses usually induce a profound remodeling of host cells, including the usurpation of host machinery to support their replication and production of virions to invade new cells. Nonetheless, recognition of viruses by the host often triggers innate immune signaling, preventing viral spread and modulating the function of immune cells. It conventionally occurs through production of antiviral factors and cytokines by infected cells. Virtually all viruses have evolved mechanisms to blunt such responses. Importantly, it is becoming increasingly recognized that infected cells also transmit signals to regulate innate immunity in uninfected neighboring cells. These alternative pathways are notably mediated by vesicular secretion of various virus- and host-derived products (miRNAs, RNAs, and proteins) and non-infectious viral particles. In this review, we focus on these newly-described modes of cell-to-cell communications and their impact on neighboring cell functions. The reception of these signals can have anti- and pro-viral impacts, as well as more complex effects in the host such as oncogenesis and inflammation. Therefore, these “broadcasting” functions, which might be tuned by an arms race involving selective evolution driven by either the host or the virus, constitute novel and original regulations of viral infection, either highly localized or systemic. PMID:26295405

A microRNA-mRNA expression network during oral siphon regeneration in Ciona

PubMed Central

Spina, Elijah J.; Guzman, Elmer; Zhou, Hongjun; Kosik, Kenneth S.

2017-01-01

Here we present a parallel study of mRNA and microRNA expression during oral siphon (OS) regeneration in Ciona robusta, and the derived network of their interactions. In the process of identifying 248 mRNAs and 15 microRNAs as differentially expressed, we also identified 57 novel microRNAs, several of which are among the most highly differentially expressed. Analysis of functional categories identified enriched transcripts related to stress responses and apoptosis at the wound healing stage, signaling pathways including Wnt and TGFβ during early regrowth, and negative regulation of extracellular proteases in late stage regeneration. Consistent with the expression results, we found that inhibition of TGFβ signaling blocked OS regeneration. A correlation network was subsequently inferred for all predicted microRNA-mRNA target pairs expressed during regeneration. Network-based clustering associated transcripts into 22 non-overlapping groups, the functional analysis of which showed enrichment of stress response, signaling pathway and extracellular protease categories that could be related to specific microRNAs. Predicted targets of the miR-9 cluster suggest a role in regulating differentiation and the proliferative state of neural progenitors through regulation of the cytoskeleton and cell cycle. PMID:28432214

Flg22 regulates the release of an ethylene response factor substrate from MAP kinase 6 in Arabidopsis thaliana via ethylene signaling

PubMed Central

Bethke, Gerit; Unthan, Tino; Uhrig, Joachim F.; Pöschl, Yvonne; Gust, Andrea A.; Scheel, Dierk; Lee, Justin

2009-01-01

Mitogen-activated protein kinase (MAPK)–mediated responses are in part regulated by the repertoire of MAPK substrates, which is still poorly elucidated in plants. Here, the in vivo enzyme–substrate interaction of the Arabidopsis thaliana MAP kinase, MPK6, with an ethylene response factor (ERF104) is shown by fluorescence resonance energy transfer. The interaction was rapidly lost in response to flagellin-derived flg22 peptide. This complex disruption requires not only MPK6 activity, which also affects ERF104 stability via phosphorylation, but also ethylene signaling. The latter points to a novel role of ethylene in substrate release, presumably allowing the liberated ERF104 to access target genes. Microarray data show enrichment of GCC motifs in the promoters of ERF104–up-regulated genes, many of which are stress related. ERF104 is a vital regulator of basal immunity, as altered expression in both erf104 and overexpressors led to more growth inhibition by flg22 and enhanced susceptibility to a non-adapted bacterial pathogen. PMID:19416906

DAN (NBL1) specifically antagonizes BMP2 and BMP4 and modulates the actions of GDF9, BMP2, and BMP4 in the rat ovary.

PubMed

Hung, Wei-Ting; Wu, Fang-Ju; Wang, Chun-Jen; Luo, Ching-Wei

2012-05-01

Although differential screening-selected gene aberrative in neuroblastoma (DAN, official symbol NBL1) is the founding member of the DAN subfamily of bone morphogenetic protein (BMP) antagonists, its antagonizing targets, gene regulation, and physiological functions remain unclear. Using diverse cell expression systems, we found that the generation of bioactive DAN is likely to be cell type specific. Unlike other phylogenetically close members, which are covalently linked homodimers, DAN forms a noncovalently linked homodimer during folding. Purified recombinant DAN specifically blocked signaling of BMP2 and BMP4 but not that of other ovarian-expressed transforming growth factor-beta members. Although widely distributed in many organs, DAN transcript level was periodically regulated by gonadotropins. Ovarian microdissection indicated that NBL1 (DAN) mRNA is mainly expressed in granulosa cells, where its transcript level is up-regulated by the gonadotropin-driven cAMP cascade. We further investigated the local regulation and ovarian functions of DAN. NBL1 (DAN) mRNA expression in granulosa cells was up-regulated by oocyte-derived growth differentiation factor 9 (GDF9), whereas treatment with DAN significantly reversed the inhibitory effect of BMP4 on follicle-stimulating hormone-induced progesterone production in cultured granulosa cells. Our findings suggest the DAN gradient in granulosa cells, established by oocyte-derived GDF9, may serve as an antagonist barrier that modulates the actions of theca-derived BMP4 and granulosa/theca-derived BMP2 during folliculogenesis both spatially and temporally.

Scientific familial lessons in ingestive behavior research: 2016 Alan N. Epstein research award.

PubMed

Hayes, Matthew R

2017-07-01

While energy balance is under the control of the central nervous system (CNS), a major source of neural regulation for the behavioral, physiological and endocrine processes governing energy balance originates in the periphery. Indeed, the organs of the gastrointestinal (GI) tract, supporting organs of the peritoneal cavity and adipose tissue are the source of numerous neurotransmitter and neuroendocrine signals released from non-neuronal peripheral tissue that signal in a paracrine and endocrine fashion to regulate the physiological and behavioral processes that affect energy balance. Given the ever increasing appreciation that chronic hyperphagia of highly-palatable/rewarding food is a major contributing factor to the obesity epidemic, it is not surprising that the field has increased research efforts focusing on understanding what role peripherally-derived neuroendocrine signals play in modulating food reward and motivated behaviors. Research throughout my career has focused on understanding gut-to-brain communication of relevance to energy balance control. Through very fortuitous opportunities and amazing collaborations, my research program has also expanded widely to include analyses of multiple GI-, pancreatic- and adipose tissue-derived anorectic signals involved in food intake and energy balance control, as well as analyses of higher-order determinants of food reward, nausea, aversion and maladaptive motivated behaviors. I am honored to be the recipient of the 2016 Alan N. Epstein Research Award from the Society for the Study of Ingestive Behavior, and express much appreciation for the amazing collaborations I have had with my mentors, colleagues and trainees. Copyright © 2017 Elsevier Inc. All rights reserved.

Proteome Dynamics in Biobanked Horse Peripheral Blood Derived Lymphocytes (PBL) with Induced Autoimmune Uveitis.

PubMed

Hauck, Stefanie M; Lepper, Marlen F; Hertl, Michael; Sekundo, Walter; Deeg, Cornelia A

2017-10-01

Equine recurrent uveitis is the only spontaneous model for recurrent autoimmune uveitis in humans, where T cells target retinal proteins. Differences between normal and autoaggressive lymphocytes were identified in this study by analyzing peripheral blood derived lymphocytes (PBL) proteomes from the same case with interphotoreceptor retinoid binding protein induced uveitis sampled before (Day 0), during (Day 15), and after uveitic attack (Day 23). Relative protein abundances of PBL were investigated in a quantitative, label-free differential proteome analysis in cells that were kept frozen for 14 years since the initial experiment. Quantitative data could be acquired for 2632 proteins at all three time points. Profound changes (≥2-fold change) in PBL protein abundance were observed when comparing Day 0 with 15, representing acute inflammation (1070 regulated proteins) and Day 0 with 23 (cessation; 1571 regulated). Significant differences applied to proteins with functions in integrin signaling during active uveitis, involving "Erk and pi-3 kinase are necessary for collagen binding in corneal epithelia," "integrins in angiogenesis," and "integrin-linked kinase signaling" pathways. In contrast, at cessation of uveitic attack, significantly changed proteins belonged to pathways of "nongenotropic androgen signaling," "classical complement pathway," and "Amb2 integrin signaling." Several members of respective pathways were earlier shown to be changed in naturally occurring uveitis, underscoring the significance of these findings here and proofing the value of the induced model in mimicking spontaneous autoimmune uveitis. All MS data have been deposited to the ProteomeXchange consortium via the PRIDE partner repository (dataset identifier PXD005580). © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Maize and Arabidopsis ARGOS Proteins Interact with Ethylene Receptor Signaling Complex, Supporting a Regulatory Role for ARGOS in Ethylene Signal Transduction[OPEN

PubMed Central

Shi, Jinrui; Wang, Hongyu; Habben, Jeffrey E.

2016-01-01

The phytohormone ethylene regulates plant growth and development as well as plant response to environmental cues. ARGOS genes reduce plant sensitivity to ethylene when overexpressed in transgenic Arabidopsis (Arabidopsis thaliana) and maize (Zea mays). A previous genetic study suggested that the endoplasmic reticulum and Golgi-localized maize ARGOS1 targets the ethylene signal transduction components at or upstream of CONSTITUTIVE TRIPLE RESPONSE1, but the mechanism of ARGOS modulating ethylene signaling is unknown. Here, we demonstrate in Arabidopsis that ZmARGOS1, as well as the Arabidopsis ARGOS homolog ORGAN SIZE RELATED1, physically interacts with Arabidopsis REVERSION-TO-ETHYLENE SENSITIVITY1 (RTE1), an ethylene receptor interacting protein that regulates the activity of ETHYLENE RESPONSE1. The protein-protein interaction was also detected with the yeast split-ubiquitin two-hybrid system. Using the same yeast assay, we found that maize RTE1 homolog REVERSION-TO-ETHYLENE SENSITIVITY1 LIKE4 (ZmRTL4) and ZmRTL2 also interact with maize and Arabidopsis ARGOS proteins. Like AtRTE1 in Arabidopsis, ZmRTL4 and ZmRTL2 reduce ethylene responses when overexpressed in maize, indicating a similar mechanism for ARGOS regulating ethylene signaling in maize. A polypeptide fragment derived from ZmARGOS8, consisting of a Pro-rich motif flanked by two transmembrane helices that are conserved among members of the ARGOS family, can interact with AtRTE1 and maize RTL proteins in Arabidopsis. The conserved domain is necessary and sufficient to reduce ethylene sensitivity in Arabidopsis and maize. Overall, these results suggest a physical association between ARGOS and the ethylene receptor signaling complex via AtRTE1 and maize RTL proteins, supporting a role for ARGOS in regulating ethylene perception and the early steps of signal transduction in Arabidopsis and maize. PMID:27268962

Maize and Arabidopsis ARGOS Proteins Interact with Ethylene Receptor Signaling Complex, Supporting a Regulatory Role for ARGOS in Ethylene Signal Transduction.

PubMed

Shi, Jinrui; Drummond, Bruce J; Wang, Hongyu; Archibald, Rayeann L; Habben, Jeffrey E

2016-08-01

The phytohormone ethylene regulates plant growth and development as well as plant response to environmental cues. ARGOS genes reduce plant sensitivity to ethylene when overexpressed in transgenic Arabidopsis (Arabidopsis thaliana) and maize (Zea mays). A previous genetic study suggested that the endoplasmic reticulum and Golgi-localized maize ARGOS1 targets the ethylene signal transduction components at or upstream of CONSTITUTIVE TRIPLE RESPONSE1, but the mechanism of ARGOS modulating ethylene signaling is unknown. Here, we demonstrate in Arabidopsis that ZmARGOS1, as well as the Arabidopsis ARGOS homolog ORGAN SIZE RELATED1, physically interacts with Arabidopsis REVERSION-TO-ETHYLENE SENSITIVITY1 (RTE1), an ethylene receptor interacting protein that regulates the activity of ETHYLENE RESPONSE1. The protein-protein interaction was also detected with the yeast split-ubiquitin two-hybrid system. Using the same yeast assay, we found that maize RTE1 homolog REVERSION-TO-ETHYLENE SENSITIVITY1 LIKE4 (ZmRTL4) and ZmRTL2 also interact with maize and Arabidopsis ARGOS proteins. Like AtRTE1 in Arabidopsis, ZmRTL4 and ZmRTL2 reduce ethylene responses when overexpressed in maize, indicating a similar mechanism for ARGOS regulating ethylene signaling in maize. A polypeptide fragment derived from ZmARGOS8, consisting of a Pro-rich motif flanked by two transmembrane helices that are conserved among members of the ARGOS family, can interact with AtRTE1 and maize RTL proteins in Arabidopsis. The conserved domain is necessary and sufficient to reduce ethylene sensitivity in Arabidopsis and maize. Overall, these results suggest a physical association between ARGOS and the ethylene receptor signaling complex via AtRTE1 and maize RTL proteins, supporting a role for ARGOS in regulating ethylene perception and the early steps of signal transduction in Arabidopsis and maize. © 2016 American Society of Plant Biologists. All Rights Reserved.

A critical role for PDGFRα signaling in medial nasal process development.

PubMed

He, Fenglei; Soriano, Philippe

2013-01-01

The primitive face is composed of neural crest cell (NCC) derived prominences. The medial nasal processes (MNP) give rise to the upper lip and vomeronasal organ, and are essential for normal craniofacial development, but the mechanism of MNP development remains largely unknown. PDGFRα signaling is known to be critical for NCC development and craniofacial morphogenesis. In this study, we show that PDGFRα is required for MNP development by maintaining the migration of progenitor neural crest cells (NCCs) and the proliferation of MNP cells. Further investigations reveal that PI3K/Akt and Rac1 signaling mediate PDGFRα function during MNP development. We thus establish PDGFRα as a novel regulator of MNP development and elucidate the roles of its downstream signaling pathways at cellular and molecular levels.

Wnt and BMP Signaling Crosstalk in Regulating Dental Stem Cells: Implications in Dental Tissue Engineering

PubMed Central

Zhang, Fugui; Song, Jinglin; Zhang, Hongmei; Huang, Enyi; Song, Dongzhe; Tollemar, Viktor; Wang, Jing; Wang, Jinhua; Mohammed, Maryam; Wei, Qiang; Fan, Jiaming; Liao, Junyi; Zou, Yulong; Liu, Feng; Hu, Xue; Qu, Xiangyang; Chen, Liqun; Yu, Xinyi; Luu, Hue H.; Lee, Michael J.; He, Tong-Chuan; Ji, Ping

2016-01-01

Tooth is a complex hard tissue organ and consists of multiple cell types that are regulated by important signaling pathways such as Wnt and BMP signaling. Serious injuries and/or loss of tooth or periodontal tissues may significantly impact aesthetic appearance, essential oral functions and the quality of life. Regenerative dentistry holds great promise in treating oral/dental disorders. The past decade has witnessed a rapid expansion of our understanding of the biological features of dental stem cells, along with the signaling mechanisms governing stem cell self-renewal and differentiation. In this review, we first summarize the biological characteristics of seven types of dental stem cells, including dental pulp stem cells, stem cells from apical papilla, stem cells from human exfoliated deciduous teeth, dental follicle precursor cells, periodontal ligament stem cells, alveolar bone-derived mesenchymal stem cells (MSCs), and MSCs from gingiva. We then focus on how these stem cells are regulated by bone morphogenetic protein (BMP) and/or Wnt signaling by examining the interplays between these pathways. Lastly, we analyze the current status of dental tissue engineering strategies that utilize oral/dental stem cells by harnessing the interplays between BMP and Wnt pathways. We also highlight the challenges that must be addressed before the dental stem cells may reach any clinical applications. Thus, we can expect to witness significant progresses to be made in regenerative dentistry in the coming decade. PMID:28491933

Gα73B is a downstream effector of JAK/STAT signalling and a regulator of Rho1 in Drosophila haematopoiesis.

PubMed

Bausek, Nina; Zeidler, Martin P

2014-01-01

JAK/STAT signalling regulates many essential developmental processes including cell proliferation and haematopoiesis, whereas its inappropriate activation is associated with the majority of myeloproliferative neoplasias and numerous cancers. Furthermore, high levels of JAK/STAT pathway signalling have also been associated with enhanced metastatic invasion by cancerous cells. Strikingly, gain-of-function mutations in the single Drosophila JAK homologue, Hopscotch, result in haemocyte neoplasia, inappropriate differentiation and the formation of melanised haemocyte-derived 'tumour' masses; phenotypes that are partly orthologous to human gain-of-function JAK2-associated pathologies. Here we show that Gα73B, a novel JAK/STAT pathway target gene, is necessary for JAK/STAT-mediated tumour formation in flies. In addition, although Gα73B does not affect haemocyte differentiation, it does regulate haemocyte morphology and motility under non-pathological conditions. We show that Gα73B is required for constitutive, but not injury-induced, activation of Rho1 and for the localisation of Rho1 into filopodia upon haemocyte activation. Consistent with these results, we also show that Rho1 interacts genetically with JAK/STAT signalling, and that wild-type levels of Rho1 are necessary for tumour formation. Our findings link JAK/STAT transcriptional outputs, Gα73B activity and Rho1-dependent cytoskeletal rearrangements and cell motility, therefore connecting a pathway associated with cancer with a marker indicative of invasiveness. As such, we suggest a mechanism by which JAK/STAT pathway signalling may promote metastasis.

PI3 K/Akt/mTOR-mediated translational control regulates proliferation and differentiation of lineage-restricted RoSH stem cell lines

PubMed Central

Que, Jianwen; Lian, Qizhou; El Oakley, Reida M; Lim, Bing; Lim, Sai-Kiang

2007-01-01

Background We have previously derived highly similar lineage-restricted stem cell lines, RoSH and E-RoSH cell lines from mouse embryos and CD9hi SSEA-1- differentiated mouse embryonic stem cells, respectively. These cell lines are not pluripotent and differentiate readily into endothelial cells in vitro and in vivo. Results We investigated the signaling pathway that maintains proliferation of these cells in an undifferentiated state, and demonstrate that PI3 K/Akt/mTOR, but not Raf/MEK/Erk, signaling in these cells was active during proliferation and was downregulated during endothelial differentiation. Inhibition of PI3 K/Akt/mTOR signaling, but not Raf/MEK/Erk, reduced proliferation and induced expression of endothelial specific proteins. During differentiation or inhibition of PI3 K/Akt/mTOR signaling, cyclinD2 transcript abundance in ribosome-enriched RNA but not in total RNA was reduced with a corresponding reduction in protein level. In contrast, transcript abundance of endothelial-specific genes e.g. Kdr, Tek and Pdgfrα in ribosome-enriched RNA fraction was not reduced and their protein levels were increased. Together these observations suggested that translational control mediated by PI3K/Akt/mTOR signaling was critical in regulating proliferation and endothelial differentiation of lineage-restricted RoSH-like stem cell lines. Conclusion This study highlights translation regulation as a critical regulatory mechanism during proliferation and differentiation in stem cells. PMID:17892597

TMEM203 Is a Novel Regulator of Intracellular Calcium Homeostasis and Is Required for Spermatogenesis

PubMed Central

Shambharkar, Prashant B.; Bittinger, Mark; Latario, Brian; Xiong, ZhaoHui; Bandyopadhyay, Somnath; Davis, Vanessa; Lin, Victor; Yang, Yi; Valdez, Reginald; Labow, Mark A.

2015-01-01

Intracellular calcium signaling is critical for initiating and sustaining diverse cellular functions including transcription, synaptic signaling, muscle contraction, apoptosis and fertilization. Trans-membrane 203 (TMEM203) was identified here in cDNA overexpression screens for proteins capable of modulating intracellular calcium levels using activation of a calcium/calcineurin regulated transcription factor as an indicator. Overexpression of TMEM203 resulted in a reduction of Endoplasmic Reticulum (ER) calcium stores and elevation in basal cytoplasmic calcium levels. TMEM203 protein was localized to the ER and found associated with a number of ER proteins which regulate ER calcium entry and efflux. Mouse Embryonic Fibroblasts (MEFs) derived from Tmem203 deficient mice had reduced ER calcium stores and altered calcium homeostasis. Tmem203 deficient mice were viable though male knockout mice were infertile and exhibited a severe block in spermiogenesis and spermiation. Expression profiling studies showed significant alternations in expression of calcium channels and pumps in testes and concurrently Tmem203 deficient spermatocytes demonstrated significantly altered calcium handling. Thus Tmem203 is an evolutionarily conserved regulator of cellular calcium homeostasis, is required for spermatogenesis and provides a causal link between intracellular calcium regulation and spermiogenesis. PMID:25996873

Intracellular biosynthesis of lipids and cholesterol by Scap and Insig in mesenchymal cells regulates long bone growth and chondrocyte homeostasis.

PubMed

Tsushima, Hidetoshi; Tang, Yuning J; Puviindran, Vijitha; Hsu, Shu-Hsuan Claire; Nadesan, Puviindran; Yu, Chunying; Zhang, Hongyuan; Mirando, Anthony J; Hilton, Matthew J; Alman, Benjamin A

2018-06-13

During enchondral ossification, mesenchymal cells express genes regulating the intracellular biosynthesis of cholesterol and lipids. Here we investigated conditional deletion of Scap or Insig1 and Insig2 (inhibits or activates intracellular biosynthesis respectively). Mesenchymal condensation and chondrogenesis was disrupted in mice lacking Scap in mesenchymal progenitors, while mice lacking the Insig genes in mesenchymal progenitors had short limbs, but normal chondrogenesis. Mice lacking Scap in chondrocytes showed severe dwarfism, with ectopic hypertrophic cells, while deletion of Insig genes in chondrocytes caused a mild dwarfism and shorting of the hypertrophic zone. In-vitro studies showed that intracellular cholesterol in chondrocytes can derive from exogenous and endogenous sources, but that exogenous sources cannot completely overcome the phenotypic effect of Scap deficiency. Genes encoding cholesterol biosynthetic proteins are regulated by Hedgehog (Hh) signaling, and Hh signaling is also regulated by intracellular cholesterol in chondrocytes, suggesting a feedback loop in chondrocyte differentiation. Precise regulation of intracellular biosynthesis is required for chondrocyte homeostasis and long bone growth, and this data supports pharmacologic modulation of cholesterol biosynthesis as a therapy for select cartilage pathologies. © 2018. Published by The Company of Biologists Ltd.

Inhibitory effect of ginsenoside Rg1 on extracellular matrix production via extracellular signal-regulated protein kinase/activator protein 1 pathway in nasal polyp-derived fibroblasts.

PubMed

Cho, Jung-Sun; Moon, You-Mi; Um, Ji-Young; Moon, Jun-Hyeok; Park, Il-Ho; Lee, Heung-Man

2012-06-01

Nasal polyps are associated with chronic inflammation of the sinonasal mucosa and are involved in myofibroblast differentiation and extracellular matrix (ECM) accumulation. Ginsenoside Rg1, a compound derived from Panax ginseng, shows antifibrotic and anticancer effects. However, the molecular effects of Rg1 on myofibroblast differentiation and ECM production remain unknown. The aims of this study were to investigate the effect of Rg1 on transforming growth factor (TGF)-β1-induced myofibroblast differentiation and ECM production and to determine the molecular mechanism of Rg1 in nasal polyp-derived fibroblasts (NPDFs). NPDFs were isolated from nasal polyps of seven patients who had chronic rhinosinusitis with nasal polyp. NPDFs were exposed to TGF-β1 with or without Rg1. Expression levels of α-smooth muscle actin (SMA), fibronectin and collagen type Iα1 were determined by reverse transcription polymerase chain reaction, Western blot and immunofluorescent staining. TGF-β1 signaling molecules, including Smad2/3, extracellular signal-regulated protein kinase (ERK), c-Jun N-terminal kinase (JNK) and p38 were analyzed by Western blotting. Transcription factors involved with TGF-β1 signaling, nuclear factor (NF)-κB and activator protein 1 (AP-1) were also assessed by Western blot. The cytotoxic effect of Rg1 was measured by an established viability assay. The mRNA and protein expression levels of α-SMA, fibronectin and collagen type Iα1 were increased in TGF-β1-induced NPDFs. Rg1 inhibited these effects. The inhibitory molecular mechanism of Rg1 was involved in the ERK pathway. Rg1 inhibited the transcription factor activation of AP-1. Rg1 itself was not cytotoxic. The ginsenoside Rg1 has inhibitory effects on myofibroblast differentiation and ECM production. The inhibitory mechanism of Rg1 is involved with the ERK and AP-1 signaling pathways. Rg1 may be useful as an inhibitor of ECM deposition, and has potential to be used as a novel treatment option for nasal polyps.

cDNA Microarray Gene Expression Profiling of Hedgehog Signaling Pathway Inhibition in Human Colon Cancer Cells

PubMed Central

Shi, Ting; Mazumdar, Tapati; DeVecchio, Jennifer; Duan, Zhong-Hui; Agyeman, Akwasi; Aziz, Mohammad; Houghton, Janet A.

2010-01-01

Background Hedgehog (HH) signaling plays a critical role in normal cellular processes, in normal mammalian gastrointestinal development and differentiation, and in oncogenesis and maintenance of the malignant phenotype in a variety of human cancers. Increasing evidence further implicates the involvement of HH signaling in oncogenesis and metastatic behavior of colon cancers. However, genomic approaches to elucidate the role of HH signaling in cancers in general are lacking, and data derived on HH signaling in colon cancer is extremely limited. Methodology/Principal Findings To identify unique downstream targets of the GLI genes, the transcriptional regulators of HH signaling, in the context of colon carcinoma, we employed a small molecule inhibitor of both GLI1 and GLI2, GANT61, in two human colon cancer cell lines, HT29 and GC3/c1. Cell cycle analysis demonstrated accumulation of GANT61-treated cells at the G1/S boundary. cDNA microarray gene expression profiling of 18,401 genes identified Differentially Expressed Genes (DEGs) both common and unique to HT29 and GC3/c1. Analyses using GenomeStudio (statistics), Matlab (heat map), Ingenuity (canonical pathway analysis), or by qRT-PCR, identified p21Cip1 (CDKN1A) and p15Ink4b (CDKN2B), which play a role in the G1/S checkpoint, as up-regulated genes at the G1/S boundary. Genes that determine further cell cycle progression at G1/S including E2F2, CYCLIN E2 (CCNE2), CDC25A and CDK2, and genes that regulate passage of cells through G2/M (CYCLIN A2 [CCNA2], CDC25C, CYCLIN B2 [CCNB2], CDC20 and CDC2 [CDK1], were down-regulated. In addition, novel genes involved in stress response, DNA damage response, DNA replication and DNA repair were identified following inhibition of HH signaling. Conclusions/Significance This study identifies genes that are involved in HH-dependent cellular proliferation in colon cancer cells, and following its inhibition, genes that regulate cell cycle progression and events downstream of the G1/S boundary. PMID:20957031

IGF-1 signaling mediated cell-specific skeletal mechano-transduction.

PubMed

Tian, Faming; Wang, Yongmei; Bikle, Daniel D

2018-02-01

Mechanical loading preserves bone mass and stimulates bone formation, whereas skeletal unloading leads to bone loss. In addition to osteocytes, which are considered the primary sensor of mechanical load, osteoblasts, and bone specific mesenchymal stem cells also are involved. The skeletal response to mechanical signals is a complex process regulated by multiple signaling pathways including that of insulin-like growth factor-1 (IGF-1). Conditional osteocyte deletion of IGF-1 ablates the osteogenic response to mechanical loading. Similarly, osteocyte IGF-1 receptor (IGF-1R) expression is necessary for reloading-induced periosteal bone formation. Transgenic overexpression of IGF-1 in osteoblasts results in enhanced responsiveness to in vivo mechanical loading in mice, a response which is eliminated by osteoblastic conditional disruption of IGF-1 in vivo. Bone marrow derived stem cells (BMSC) from unloaded bone fail to respond to IGF-1 in vitro. IGF-1R is required for the transduction of a mechanical stimulus to downstream effectors, transduction which is lost when the IGF-1R is deleted. Although the molecular mechanisms are not yet fully elucidated, the IGF signaling pathway and its interactions with potentially interlinked signaling cascades involving integrins, the estrogen receptor, and wnt/β-catenin play an important role in regulating adaptive response of cancer bone cells to mechanical stimuli. In this review, we discuss recent advances investigating how IGF-1 and other interlinked molecules and signaling pathways regulate skeletal mechano-transduction involving different bone cells, providing an overview of the IGF-1 signaling mediated cell-specific response to mechanical stimuli. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:576-583, 2018. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.

Defects in subventricular zone pigmented epithelium-derived factor niche signaling in the senescence-accelerated mouse prone-8.

PubMed

Castro-Garcia, Paola; Díaz-Moreno, María; Gil-Gas, Carmen; Fernández-Gómez, Francisco J; Honrubia-Gómez, Paloma; Álvarez-Simón, Carmen Belén; Sánchez-Sánchez, Francisco; Cano, Juan Carlos Castillo; Almeida, Francisco; Blanco, Vicente; Jordán, Joaquín; Mira, Helena; Ramírez-Castillejo, Carmen

2015-04-01

We studied potential changes in the subventricular zone (SVZ) stem cell niche of the senescence-accelerated mouse prone-8 (SAM-P8) aging model. Bromodeoxyuridine (BrdU) assays with longtime survival revealed a lower number of label-retaining stem cells in the SAM-P8 SVZ compared with the SAM-Resistant 1 (SAM-R1) control strain. We also found that in SAM-P8 niche signaling is attenuated and the stem cell pool is less responsive to the self-renewal niche factor pigmented epithelium-derived factor (PEDF). Protein analysis demonstrated stable amounts of the PEDF ligand in the SAM-P8 SVZ niche; however, SAM-P8 stem cells present a significant expression decrease of patatin-like phospholipase domain containing 2, a receptor for PEDF (PNPLA2-PEDF) receptor, but not of laminin receptor (LR), a receptor for PEDF (LR-PEDF) receptor. We observed changes in self-renewal related genes (hairy and enhancer of split 1 (Hes1), hairy and enhancer of split 1 (Hes5), Sox2] and report that although these genes are down-regulated in SAM-P8, differentiation genes (Pax6) are up-regulated and neurogenesis is increased. Finally, sheltering mammalian telomere complexes might be also involved given a down-regulation of telomeric repeat binding factor 1 (Terf1) expression was observed in SAM-P8 at young age periods. Differences between these 2 models, SAM-P8 and SAM-R1 controls, have been previously detected at more advanced ages. We now describe alterations in the PEDF signaling pathway and stem cell self-renewal at a very young age, which could be involved in the premature senescence observed in the SAM-P8 model. © FASEB.

A synthetic diosgenin primary amine derivative attenuates LPS-stimulated inflammation via inhibition of NF-κB and JNK MAPK signaling in microglial BV2 cells.

PubMed

Cai, Bangrong; Seong, Kyung-Joo; Bae, Sun-Woong; Chun, Changju; Kim, Won-Jae; Jung, Ji-Yeon

2018-06-08

Diosgenin, a precursor of steroid hormones in plants, is known to exhibit diverse pharmacological activities including anti-inflammatory properties. In this study, (3β, 25R)‑spirost‑5‑en‑3‑oxyl (2‑((2((2‑aminoethyl)amino)ethyl)amino)ethyl) carbamate (DGP), a new synthetic diosgenin derivative incorporating primary amine was used to investigate its anti-inflammatory effects and underlying mechanisms of action in lipopolysaccharide (LPS)-stimulated microglial BV2 cells. Pretreatment with DGP resulted in significant inhibition of nitric oxide (NO) synthesis, and down-regulation of nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) in LPS-stimulated microglial BV2 cells. In addition, DGP decreased the production of reactive oxygen species (ROS) and pro-inflammatory cytokines such as interleukin (IL)-6, IL-1β, and tumor necrosis factor alpha (TNF-α). The inhibitory effects of DGP on these inflammatory mediators in LPS-stimulated microglial BV2 cells were regulated by NF-κB signaling through blocking p65 nuclear translocation and NF-κB p65/DNA binding activity. DGP also blocked the phosphorylation of c-Jun amino-terminal kinase (JNK), but not p38 kinase or extracellular signal-regulated kinases (ERK). The NF-κB inhibitor JSH-23 and JNK-specific inhibitor SP600125 significantly decreased NO production and IL-6 release in LPS-stimulated BV2 cells, respectively. The overall results demonstrate that DGP has anti-inflammatory effects on LPS-stimulated BV2 cells via inhibition of NF-κB and JNK activation, suggesting that DGP is a potential prophylactic agent in various neurodegenerative disorders. Copyright © 2018. Published by Elsevier B.V.

Zn2+-dependent Activation of the Trk Signaling Pathway Induces Phosphorylation of the Brain-enriched Tyrosine Phosphatase STEP

PubMed Central

Poddar, Ranjana; Rajagopal, Sathyanarayanan; Shuttleworth, C. William; Paul, Surojit

2016-01-01

Excessive release of Zn2+ in the brain is implicated in the progression of acute brain injuries. Although several signaling cascades have been reported to be involved in Zn2+-induced neurotoxicity, a potential contribution of tyrosine phosphatases in this process has not been well explored. Here we show that exposure to high concentrations of Zn2+ led to a progressive increase in phosphorylation of the striatal-enriched phosphatase (STEP), a component of the excitotoxic-signaling pathway that plays a role in neuroprotection. Zn2+-mediated phosphorylation of STEP61 at multiple sites (hyperphosphorylation) was induced by the up-regulation of brain-derived neurotropic factor (BDNF), tropomyosin receptor kinase (Trk) signaling, and activation of cAMP-dependent PKA (protein kinase A). Mutational studies further show that differential phosphorylation of STEP61 at the PKA sites, Ser-160 and Ser-221 regulates the affinity of STEP61 toward its substrates. Consistent with these findings we also show that BDNF/Trk/PKA mediated signaling is required for Zn2+-induced phosphorylation of extracellular regulated kinase 2 (ERK2), a substrate of STEP that is involved in Zn2+-dependent neurotoxicity. The strong correlation between the temporal profile of STEP61 hyperphosphorylation and ERK2 phosphorylation indicates that loss of function of STEP61 through phosphorylation is necessary for maintaining sustained ERK2 phosphorylation. This interpretation is further supported by the findings that deletion of the STEP gene led to a rapid and sustained increase in ERK2 phosphorylation within minutes of exposure to Zn2+. The study provides further insight into the mechanisms of regulation of STEP61 and also offers a molecular basis for the Zn2+-induced sustained activation of ERK2. PMID:26574547

Regulation of HGF and SDF-1 expression by oral fibroblasts--implications for invasion of oral cancer.

PubMed

Daly, Aisling J; McIlreavey, Leanne; Irwin, Chris R

2008-07-01

Invasion and metastasis of oral squamous cell carcinoma (OSCC) is dependent on signals received from stromal fibroblasts present in the surrounding connective tissue. The aim of this study was to investigate the regulation of expression of two important signaling molecules--HGF and SDF-1--by both stromal fibroblasts and their 'activated' form, myofibroblasts, and to determine the role of these two factors in stimulating OSCC cell invasion in vitro. Fibroblasts and myofibroblasts produced similar levels of HGF and SDF-1. IL-1alpha and OSCC cell conditioned medium both stimulated HGF and SDF-1 expression, while TGF-beta(1) inhibited production of each factor. Myofibroblast-derived conditioned medium stimulated OSCC cell invasion through matrigel. Blocking antibodies to both HGF and SDF-1 reduced the level of invasion. In fibroblast-free organotypic raft cultures, addition of HGF and SDF-1 stimulated OSCC cell invasion into the underlying collagen gel, although the pattern of invasion differed from that induced by fibroblasts. Fibroblast-derived HGF and SDF-1 appear to play central roles in the reciprocal interactions between OSCC cells and underlying stromal fibroblasts leading to the local invasion of oral cancer.

Marine polysaccharides attenuate metabolic syndrome by fermentation products and altering gut microbiota: An overview.

PubMed

Wang, Xueliang; Wang, Xin; Jiang, Hao; Cai, Chao; Li, Guoyun; Hao, Jiejie; Yu, Guangli

2018-09-01

Marine polysaccharides (MPs), including plant, animal, and microbial-derived polysaccharides, can alleviate metabolic syndrome (MetS) by different regulation mechanisms. MPs and their derivatives can attenuate MetS by vary cellular signal pathways, such as peroxisome proliferator-activated receptor, 5' adenosine monophosphate-activated protein kinase, and CCAAT/enhancer binding protein-α. Also, most of MPs cannot be degraded by human innate enzymes, but they can be degraded and fermented by human gut microbiota. The final metabolic products of these polysaccharides are usually short-chain fatty acids (SCFAs), which can change the gut microbiota ecology by altering the existing percentage of special microorganisms. In addition, the SCFAs and changed gut microbiota can regulate enteroendocrine hormone secretion, blood glucose, lipid metabolism levels, and other MetS symptoms. Here, we summarize the up-to-date findings on the effects of MPs, particularly marine microbial-derived polysaccharides, and their metabolites on attenuating MetS. Copyright © 2018 Elsevier Ltd. All rights reserved.

Tryptophan derivatives regulate the transcription of Oct4 in stem-like cancer cells.

PubMed

Cheng, Jie; Li, Wenxin; Kang, Bo; Zhou, Yanwen; Song, Jiasheng; Dan, Songsong; Yang, Ying; Zhang, Xiaoqian; Li, Jingchao; Yin, Shengyong; Cao, Hongcui; Yao, Hangping; Zhu, Chenggang; Yi, Wen; Zhao, Qingwei; Xu, Xiaowei; Zheng, Min; Zheng, Shusen; Li, Lanjuan; Shen, Binghui; Wang, Ying-Jie

2015-06-10

The aryl hydrocarbon receptor (AhR), a ligand-activated transcription factor that responds to environmental toxicants, is increasingly recognized as a key player in embryogenesis and tumorigenesis. Here we show that a variety of tryptophan derivatives that act as endogenous AhR ligands can affect the transcription level of the master pluripotency factor Oct4. Among them, ITE enhances the binding of the AhR to the promoter of Oct4 and suppresses its transcription. Reduction of endogenous ITE levels in cancer cells by tryptophan deprivation or hypoxia leads to Oct4 elevation, which can be reverted by administration with synthetic ITE. Consequently, synthetic ITE induces the differentiation of stem-like cancer cells and reduces their tumorigenic potential in both subcutaneous and orthotopic xenograft tumour models. Thus, our results reveal a role of tryptophan derivatives and the AhR signalling pathway in regulating cancer cell stemness and open a new therapeutic avenue to target stem-like cancer cells.

Tryptophan derivatives regulate the transcription of Oct4 in stem-like cancer cells

PubMed Central

Cheng, Jie; Li, Wenxin; Kang, Bo; Zhou, Yanwen; Song, Jiasheng; Dan, Songsong; Yang, Ying; Zhang, Xiaoqian; Li, Jingchao; Yin, Shengyong; Cao, Hongcui; Yao, Hangping; Zhu, Chenggang; Yi, Wen; Zhao, Qingwei; Xu, Xiaowei; Zheng, Min; Zheng, Shusen; Li, Lanjuan; Shen, Binghui; Wang, Ying-Jie

2015-01-01

The aryl hydrocarbon receptor (AhR), a ligand-activated transcription factor that responds to environmental toxicants, is increasingly recognized as a key player in embryogenesis and tumorigenesis. Here we show that a variety of tryptophan derivatives that act as endogenous AhR ligands can affect the transcription level of the master pluripotency factor Oct4. Among them, ITE enhances the binding of the AhR to the promoter of Oct4 and suppresses its transcription. Reduction of endogenous ITE levels in cancer cells by tryptophan deprivation or hypoxia leads to Oct4 elevation, which can be reverted by administration with synthetic ITE. Consequently, synthetic ITE induces the differentiation of stem-like cancer cells and reduces their tumorigenic potential in both subcutaneous and orthotopic xenograft tumour models. Thus, our results reveal a role of tryptophan derivatives and the AhR signalling pathway in regulating cancer cell stemness and open a new therapeutic avenue to target stem-like cancer cells. PMID:26059097

The chemokine receptor CCR1 is identified in mast cell-derived exosomes

PubMed Central

Liang, Yuting; Qiao, Longwei; Peng, Xia; Cui, Zelin; Yin, Yue; Liao, Huanjin; Jiang, Min; Li, Li

2018-01-01

Mast cells are important effector cells of the immune system, and mast cell-derived exosomes carrying RNAs play a role in immune regulation. However, the molecular function of mast cell-derived exosomes is currently unknown, and here, we identify differentially expressed genes (DEGs) in mast cells and exosomes. We isolated mast cells derived exosomes through differential centrifugation and screened the DEGs from mast cell-derived exosomes, using the GSE25330 array dataset downloaded from the Gene Expression Omnibus database. Biochemical pathways were analyzed by Gene ontology (GO) annotation and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway on the online tool DAVID. DEGs-associated protein-protein interaction networks (PPIs) were constructed using the STRING database and Cytoscape software. The genes identified from these bioinformatics analyses were verified by qRT-PCR and Western blot in mast cells and exosomes. We identified 2121 DEGs (843 up and 1278 down-regulated genes) in HMC-1 cell-derived exosomes and HMC-1 cells. The up-regulated DEGs were classified into two significant modules. The chemokine receptor CCR1 was screened as a hub gene and enriched in cytokine-mediated signaling pathway in module one. Seven genes, including CCR1, CD9, KIT, TGFBR1, TLR9, TPSAB1 and TPSB2 were screened and validated through qRT-PCR analysis. We have achieved a comprehensive view of the pivotal genes and pathways in mast cells and exosomes and identified CCR1 as a hub gene in mast cell-derived exosomes. Our results provide novel clues with respect to the biological processes through which mast cell-derived exosomes modulate immune responses. PMID:29511430

Estrogen improves the proliferation and differentiation of hBMSCs derived from postmenopausal osteoporosis through notch signaling pathway.

PubMed

Fan, Jin-Zhu; Yang, Liu; Meng, Guo-Lin; Lin, Yan-shui; Wei, Bo-Yuan; Fan, Jing; Hu, Hui-Min; Liu, Yan-Wu; Chen, Shi; Zhang, Jin-Kang; He, Qi-Zhen; Luo, Zhuo-Jing; Liu, Jian

2014-07-01

Estrogen deficiency is the main reason of bone loss, leading to postmenopausal osteoporosis, and estrogen replacement therapy (ERT) has been demonstrated to protect bone loss efficiently. Notch signaling controls proliferation and differentiation of bone marrow-derived mesenchymal stem cells (BMSCs). Moreover, imperfect estrogen-responsive elements (EREs) were found in the 5'-untranslated region of Notch1 and Jagged1. Thus, we examined the molecular and biological links between estrogen and the Notch signaling in postmenopausal osteoporosis in vitro. hBMSCs were obtained from healthy women and patients with postmenopausal osteoporosis. Notch signaling molecules were quantified using real-time polymerase chain reaction (real-time PCR) and Western Blot. Luciferase reporter constructs with putative EREs were transfected into hBMSCs and analyzed. hBMSCs were transduced with lentiviral vectors containing human Notch1 intracellular domain (NICD1). We also used N-[N-(3, 5-diflurophenylacetate)-l-alanyl]-(S)-phenylglycine t-butyl ester, a γ-secretase inhibitor, to suppress the Notch signaling. We found that estrogen enhanced the Notch signaling in hBMSCs by promoting the expression of Jagged1. hBMSCs cultured with estrogen resulted in the up-regulation of Notch signaling and increased proliferation and differentiation. Enhanced Notch signaling could enhance the proliferation and differentiation of hBMSCs from patients with postmenopausal osteoporosis (OP-hBMSCs). Our results demonstrated that estrogen preserved bone mass partly by activating the Notch signaling. Because long-term ERT has been associated with several side effects, the Notch signaling could be a potential target for treating postmenopausal osteoporosis.

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

Himaya, S.W.A.; Dewapriya, Pradeep; Kim, Se-Kwon, E-mail: sknkim@pknu.ac.kr

Helicobacter pylori infection is one of the most critical causes of stomach cancer. The current study was conducted to explore the protective effects of an isolated active peptide H-P-6 (Pro-Gln-Pro-Lys-Val-Leu-Asp-Ser) from microbial hydrolysates of Chlamydomonas sp. against H. pylori-induced carcinogenesis. The peptide H-P-6 has effectively suppressed H. pylori-induced hyper-proliferation and migration of gastric epithelial cells (AGS). However, the peptide did not inhibit the viability of the bacteria or invasion into AGS cells. Therefore, the effect of the peptide on regulating H. pylori-induced molecular signaling was investigated. The results indicated that H. pylori activates the EGFR tyrosine kinase signaling and nuclearmore » translocation of the β-catenin. The EGFR activation has led to the up-regulation of PI3K/Akt signaling pathway. Moreover, the nuclear translocation levels of β-catenin were significantly increased as a result of Akt mediated down-regulation of GSK3/β protein levels in the cytoplasm. Both of these consequences have resulted in increased expression of cell survival and migration related genes such as c-Myc, cyclin-D, MMP-2 and matrilysin. Interestingly, the isolated peptide potently inhibited H. pylori-mediated EGFR activation and thereby down-regulated the subsequent P13K/Akt signaling leading to β-catenin nuclear translocation. The effect of the peptide was confirmed with the use of EGFR tyrosine kinase inhibitor AG1487 and molecular docking studies. Collectively this study identifies a potent peptide which regulates the H. pylori-induced hyper-proliferation and migration of AGS cells at molecular level. - Highlights: • Chlamydomonas sp. derived peptide H-P-6 inhibits H. pylori-induced pathogenesis. • H-P-6 suppresses H. pylori-induced hyper-proliferation and migration of AGS cells. • The peptide inhibits H. pylori-induced EGFR activation.« less

Involvement of potato (Solanum tuberosum L.) MKK6 in response to potato virus Y.

PubMed

Lazar, Ana; Coll, Anna; Dobnik, David; Baebler, Spela; Bedina-Zavec, Apolonija; Zel, Jana; Gruden, Kristina

2014-01-01

Mitogen-activated protein kinase (MAPK) cascades have crucial roles in the regulation of plant development and in plant responses to stress. Plant recognition of pathogen-associated molecular patterns or pathogen-derived effector proteins has been shown to trigger activation of several MAPKs. This then controls defence responses, including synthesis and/or signalling of defence hormones and activation of defence related genes. The MAPK cascade genes are highly complex and interconnected, and thus the precise signalling mechanisms in specific plant-pathogen interactions are still not known. Here we investigated the MAPK signalling network involved in immune responses of potato (Solanum tuberosum L.) to Potato virus Y, an important potato pathogen worldwide. Sequence analysis was performed to identify the complete MAPK kinase (MKK) family in potato, and to identify those regulated in the hypersensitive resistance response to Potato virus Y infection. Arabidopsis has 10 MKK family members, of which we identified five in potato and tomato (Solanum lycopersicum L.), and eight in Nicotiana benthamiana. Among these, StMKK6 is the most strongly regulated gene in response to Potato virus Y. The salicylic acid treatment revealed that StMKK6 is regulated by the hormone that is in agreement with the salicylic acid-regulated domains found in the StMKK6 promoter. The involvement of StMKK6 in potato defence response was confirmed by localisation studies, where StMKK6 accumulated strongly only in Potato-virus-Y-infected plants, and predominantly in the cell nucleus. Using a yeast two-hybrid method, we identified three StMKK6 targets downstream in the MAPK cascade: StMAPK4_2, StMAPK6 and StMAPK13. These data together provide further insight into the StMKK6 signalling module and its involvement in plant defence.

Involvement of Potato (Solanum tuberosum L.) MKK6 in Response to Potato virus Y

PubMed Central

Lazar, Ana; Coll, Anna; Dobnik, David; Baebler, Špela; Bedina-Zavec, Apolonija; Žel, Jana; Gruden, Kristina

2014-01-01

Mitogen-activated protein kinase (MAPK) cascades have crucial roles in the regulation of plant development and in plant responses to stress. Plant recognition of pathogen-associated molecular patterns or pathogen-derived effector proteins has been shown to trigger activation of several MAPKs. This then controls defence responses, including synthesis and/or signalling of defence hormones and activation of defence related genes. The MAPK cascade genes are highly complex and interconnected, and thus the precise signalling mechanisms in specific plant–pathogen interactions are still not known. Here we investigated the MAPK signalling network involved in immune responses of potato (Solanum tuberosum L.) to Potato virus Y, an important potato pathogen worldwide. Sequence analysis was performed to identify the complete MAPK kinase (MKK) family in potato, and to identify those regulated in the hypersensitive resistance response to Potato virus Y infection. Arabidopsis has 10 MKK family members, of which we identified five in potato and tomato (Solanum lycopersicum L.), and eight in Nicotiana benthamiana. Among these, StMKK6 is the most strongly regulated gene in response to Potato virus Y. The salicylic acid treatment revealed that StMKK6 is regulated by the hormone that is in agreement with the salicylic acid-regulated domains found in the StMKK6 promoter. The involvement of StMKK6 in potato defence response was confirmed by localisation studies, where StMKK6 accumulated strongly only in Potato-virus-Y-infected plants, and predominantly in the cell nucleus. Using a yeast two-hybrid method, we identified three StMKK6 targets downstream in the MAPK cascade: StMAPK4_2, StMAPK6 and StMAPK13. These data together provide further insight into the StMKK6 signalling module and its involvement in plant defence. PMID:25111695

Regulation of cytokine signaling by B cell antigen receptor and CD40-controlled expression of heparan sulfate proteoglycans.

PubMed

van der Voort, R; Keehnen, R M; Beuling, E A; Spaargaren, M; Pals, S T

2000-10-16

Recently, biochemical, cell biological, and genetic studies have converged to reveal that integral membrane heparan sulfate proteoglycans (HSPGs) are critical regulators of growth and differentiation of epithelial and connective tissues. As a large number of cytokines involved in lymphoid tissue homeostasis or inflammation contain potential HS-binding domains, HSPGs presumably also play important roles in the regulation of the immune response. In this report, we explored the expression, regulation, and function of HSPGs on B lymphocytes. We demonstrate that activation of the B cell antigen receptor (BCR) and/or CD40 induces a strong transient expression of HSPGs on human tonsillar B cells. By means of these HSPGs, the activated B cells can bind hepatocyte growth factor (HGF), a cytokine that regulates integrin-mediated B cell adhesion and migration. This interaction with HGF is highly selective since the HSPGs did not bind the chemokine stromal cell-derived factor (SDF)-1 alpha, even though the affinities of HGF and SDF-1alpha for heparin are similar. On the activated B cells, we observed induction of a specific HSPG isoform of CD44 (CD44-HS), but not of other HSPGs such as syndecans or glypican-1. Interestingly, the expression of CD44-HS on B cells strongly promotes HGF-induced signaling, resulting in an HS-dependent enhanced phosphorylation of Met, the receptor tyrosine kinase for HGF, as well as downstream signaling molecules including Grb2-associated binder 1 (Gab1) and Akt/protein kinase B (PKB). Our results demonstrate that the BCR and CD40 control the expression of HSPGs, specifically CD44-HS. These HSPGs act as functional coreceptors that selectively promote cytokine signaling in B cells, suggesting a dynamic role for HSPGs in antigen-specific B cell differentiation.

Biological responses to PDGF-BB versus PDGF-DD in human mesangial cells.

PubMed

van Roeyen, C R C; Ostendorf, T; Denecke, B; Bokemeyer, D; Behrmann, I; Strutz, F; Lichenstein, H S; LaRochelle, W J; Pena, C E; Chaudhuri, A; Floege, J

2006-04-01

Platelet-derived growth factor (PDGF)-BB and PDGF-DD mediate mesangial cell proliferation in vitro and in vivo. While PDGF-BB is a ligand for the PDGF alpha- and beta-receptor chains, PDGF-DD binds more selectively to the beta-chain, suggesting potential differences in the biological activities. Signal transduction and regulation of gene expression induced by PDGF-BB and -DD were compared in primary human mesangial cells (HMCs), which expressed PDGF alpha- and beta-receptor subunits. The growth factor concentrations used were chosen based on their equipotency in inducing HMCs proliferation and binding to the betabeta-receptor. Both growth factors, albeit at different concentrations induced phosphorylation and activation of extracellular signal-regulated kinase 1 (ERK1) and ERK2. In addition, PDGFs led to the phosphorylation and activation of signal transducers and activators of transcription 1 (STAT1) and STAT3. HMCs proliferation induced by either PDGF-BB or -DD could be blocked by signal transduction inhibitors of the mitogen-activated protein kinase-, Janus kinase (JAK)/STAT-, or phosphatidyl-inositol 3-kinase pathways. Using a gene chip array and subsequent verification by real-time reverse transcriptase (RT)-polymerase chain reaction, we found that in HMC genes for matrix metalloproteinase 13 (MMP-13) and MMP-14 and, to a low extent, cytochrome B5 and cathepsin L were exclusively regulated by PDGF-BB, whereas no exclusive gene regulation was detected by PDGF-DD. However, at the protein level, both MMP-13 and -14 were equally induced by PDGF-BB and -DD. PDGF-BB and -DD effect similar biological responses in HMCs albeit at different potencies. Rare apparently differential gene regulation did not result in different protein expression, suggesting that in HMCs both PDGFs exert their biological activity almost exclusively via the PDGF beta-receptor.

Identification of chemicals inducing cardiomyocyte proliferation in developmental stage-specific manner with pluripotent stem cells.

PubMed

Uosaki, Hideki; Magadum, Ajit; Seo, Kinya; Fukushima, Hiroyuki; Takeuchi, Ayako; Nakagawa, Yasuaki; Moyes, Kara White; Narazaki, Genta; Kuwahara, Koichiro; Laflamme, Michael; Matsuoka, Satoshi; Nakatsuji, Norio; Nakao, Kazuwa; Kwon, Chulan; Kass, David A; Engel, Felix B; Yamashita, Jun K

2013-12-01

The proliferation of cardiomyocytes is highly restricted after postnatal maturation, limiting heart regeneration. Elucidation of the regulatory machineries for the proliferation and growth arrest of cardiomyocytes is imperative. Chemical biology is efficient to dissect molecular mechanisms of various cellular events and often provides therapeutic potentials. We have been investigating cardiovascular differentiation with pluripotent stem cells. The combination of stem cell and chemical biology can provide novel approaches to investigate the molecular mechanisms and manipulation of cardiomyocyte proliferation. To identify chemicals that regulate cardiomyocyte proliferation, we performed a screening of a defined chemical library based on proliferation of mouse pluripotent stem cell-derived cardiomyocytes and identified 4 chemical compound groups: inhibitors of glycogen synthase kinase-3, p38 mitogen-activated protein kinase, and Ca(2+)/calmodulin-dependent protein kinase II, and activators of extracellular signal-regulated kinase. Several appropriate combinations of chemicals synergistically enhanced proliferation of cardiomyocytes derived from both mouse and human pluripotent stem cells, notably up to a 14-fold increase in mouse cardiomyocytes. We also examined the effects of identified chemicals on cardiomyocytes in various developmental stages and species. Whereas extracellular signal-regulated kinase activators and Ca(2+)/calmodulin-dependent protein kinase II inhibitors showed proliferative effects only on cardiomyocytes in early developmental stages, glycogen synthase kinase-3 and p38 mitogen-activated protein kinase inhibitors substantially and synergistically induced re-entry and progression of cell cycle in neonatal but also as well as adult cardiomyocytes. Our approach successfully uncovered novel molecular targets and mechanisms controlling cardiomyocyte proliferation in distinct developmental stages and offered pluripotent stem cell-derived cardiomyocytes as a potent tool to explore chemical-based cardiac regenerative strategies.

Chronic Lymphocytic Leukemia-Derived IL-10 Suppresses Antitumor Immunity.

PubMed

Alhakeem, Sara S; McKenna, Mary K; Oben, Karine Z; Noothi, Sunil K; Rivas, Jacqueline R; Hildebrandt, Gerhard C; Fleischman, Roger A; Rangnekar, Vivek M; Muthusamy, Natarajan; Bondada, Subbarao

2018-04-30

Chronic lymphocytic leukemia (CLL) patients progressively develop an immunosuppressive state. CLL patients have more plasma IL-10, an anti-inflammatory cytokine, than healthy controls. In vitro human CLL cells produce IL-10 in response to BCR cross-linking. We used the transgenic Eμ-T cell leukemia oncogene-1 ( TCL1 ) mouse CLL model to study the role of IL-10 in CLL associated immunosuppression. Eμ-TCL mice spontaneously develop CLL because of a B cell-specific expression of the oncogene, TCL1. Eμ- TCL1 mouse CLL cells constitutively produce IL-10, which is further enhanced by BCR cross-linking, CLL-derived IL-10 did not directly affect survival of murine or human CLL cells in vitro. We tested the hypothesis that the CLL-derived IL-10 has a critical role in CLL disease in part by suppressing the host immune response to the CLL cells. In IL-10R -/- mice, wherein the host immune cells are unresponsive to IL-10-mediated suppressive effects, there was a significant reduction in CLL cell growth compared with wild type mice. IL-10 reduced the generation of effector CD4 and CD8 T cells. We also found that activation of BCR signaling regulated the production of IL-10 by both murine and human CLL cells. We identified the transcription factor, Sp1, as a novel regulator of IL-10 production by CLL cells and that it is regulated by BCR signaling via the Syk/MAPK pathway. Our results suggest that incorporation of IL-10 blocking agents may enhance current therapeutic regimens for CLL by potentiating host antitumor immune response. Copyright © 2018 by The American Association of Immunologists, Inc.

Natural Compounds as Regulators of NLRP3 Inflammasome-Mediated IL-1β Production

PubMed Central

2016-01-01

IL-1β is one of the main proinflammatory cytokines that regulates a broad range of immune responses and also participates in several physiological processes. The canonical production of IL-1β requires multiprotein complexes called inflammasomes. One of the most intensively studied inflammasome complexes is the NLRP3 inflammasome. Its activation requires two signals: one signal “primes” the cells and induces the expression of NLRP3 and pro-IL-1β, while the other signal leads to the assembly and activation of the complex. Several stimuli were reported to function as the second signal including reactive oxygen species, lysosomal rupture, or cytosolic ion perturbation. Despite very intensive studies, the precise function and regulation of the NLRP3 inflammasome are still not clear. However, many chronic inflammatory diseases are related to the overproduction of IL-1β that is mediated via the NLRP3 inflammasome. In this review, we aimed to provide an overview of studies that demonstrated the effect of plant-derived natural compounds on NLRP3 inflammasome-mediated IL-1β production. Although many of these studies lack the mechanistic explanation of their action, these compounds may be considered as complementary supplements in the treatment of chronic inflammatory diseases, consumed as preventive agents, and may also be considered as molecular tools to study NLRP3 function. PMID:27672241

Phosphatidic acid binding inhibits RGS1 activity to affect specific signaling pathways in Arabidopsis.

PubMed

Roy Choudhury, Swarup; Pandey, Sona

2017-05-01

Modulation of the active versus inactive forms of the Gα protein is critical for the signaling processes mediated by the heterotrimeric G-protein complex. We have recently established that in Arabidopsis, the regulator of G-protein signaling (RGS1) protein and a lipid-hydrolyzing enzyme, phospholipase Dα1 (PLDα1), both act as GTPase-activity accelerating proteins (GAPs) for the Gα protein to attenuate its activity. RGS1 and PLDα1 interact with each other, and RGS1 inhibits the activity of PLDα1 during regulation of a subset of responses. In this study, we present evidence that this regulation is bidirectional. Phosphatidic acid (PA), a second messenger typically derived from the lipid-hydrolyzing activity of PLDα1, is a molecular target of RGS1. PA binds and inhibits the GAP activity of RGS1. A conserved lysine residue in RGS1 (Lys 259 ) is directly involved in RGS1-PA binding. Introduction of this RGS1 protein variant in the rgs1 mutant background makes plants hypersensitive to a subset of abscisic acid-mediated responses. Our data point to the existence of negative feedback loops between these two regulatory proteins that precisely modulate the level of active Gα, consequently generating a highly controlled signal-response output. © 2017 The Authors The Plant Journal © 2017 John Wiley & Sons Ltd.

Congenital amegakaryocytic thrombocytopenia iPS cells exhibit defective MPL-mediated signaling

PubMed Central

Hirata, Shinji; Takayama, Naoya; Jono-Ohnishi, Ryoko; Endo, Hiroshi; Nakamura, Sou; Dohda, Takeaki; Nishi, Masanori; Hamazaki, Yuhei; Ishii, Ei-ichi; Kaneko, Shin; Otsu, Makoto; Nakauchi, Hiromitsu; Kunishima, Shinji; Eto, Koji

2013-01-01

Congenital amegakaryocytic thrombocytopenia (CAMT) is caused by the loss of thrombopoietin receptor–mediated (MPL-mediated) signaling, which causes severe pancytopenia leading to bone marrow failure with onset of thrombocytopenia and anemia prior to leukopenia. Because Mpl–/– mice do not exhibit the human disease phenotype, we used an in vitro disease tracing system with induced pluripotent stem cells (iPSCs) derived from a CAMT patient (CAMT iPSCs) and normal iPSCs to investigate the role of MPL signaling in hematopoiesis. We found that MPL signaling is essential for maintenance of the CD34+ multipotent hematopoietic progenitor (MPP) population and development of the CD41+GPA+ megakaryocyte-erythrocyte progenitor (MEP) population, and its role in the fate decision leading differentiation toward megakaryopoiesis or erythropoiesis differs considerably between normal and CAMT cells. Surprisingly, complimentary transduction of MPL into normal or CAMT iPSCs using a retroviral vector showed that MPL overexpression promoted erythropoiesis in normal CD34+ hematopoietic progenitor cells (HPCs), but impaired erythropoiesis and increased aberrant megakaryocyte production in CAMT iPSC–derived CD34+ HPCs, reflecting a difference in the expression of the transcription factor FLI1. These results demonstrate that impaired transcriptional regulation of the MPL signaling that normally governs megakaryopoiesis and erythropoiesis underlies CAMT. PMID:23908116

Congenital amegakaryocytic thrombocytopenia iPS cells exhibit defective MPL-mediated signaling.

PubMed

Hirata, Shinji; Takayama, Naoya; Jono-Ohnishi, Ryoko; Endo, Hiroshi; Nakamura, Sou; Dohda, Takeaki; Nishi, Masanori; Hamazaki, Yuhei; Ishii, Ei-ichi; Kaneko, Shin; Otsu, Makoto; Nakauchi, Hiromitsu; Kunishima, Shinji; Eto, Koji

2013-09-01

Congenital amegakaryocytic thrombocytopenia (CAMT) is caused by the loss of thrombopoietin receptor-mediated (MPL-mediated) signaling, which causes severe pancytopenia leading to bone marrow failure with onset of thrombocytopenia and anemia prior to leukopenia. Because Mpl(-/-) mice do not exhibit the human disease phenotype, we used an in vitro disease tracing system with induced pluripotent stem cells (iPSCs) derived from a CAMT patient (CAMT iPSCs) and normal iPSCs to investigate the role of MPL signaling in hematopoiesis. We found that MPL signaling is essential for maintenance of the CD34+ multipotent hematopoietic progenitor (MPP) population and development of the CD41+GPA+ megakaryocyte-erythrocyte progenitor (MEP) population, and its role in the fate decision leading differentiation toward megakaryopoiesis or erythropoiesis differs considerably between normal and CAMT cells. Surprisingly, complimentary transduction of MPL into normal or CAMT iPSCs using a retroviral vector showed that MPL overexpression promoted erythropoiesis in normal CD34+ hematopoietic progenitor cells (HPCs), but impaired erythropoiesis and increased aberrant megakaryocyte production in CAMT iPSC-derived CD34+ HPCs, reflecting a difference in the expression of the transcription factor FLI1. These results demonstrate that impaired transcriptional regulation of the MPL signaling that normally governs megakaryopoiesis and erythropoiesis underlies CAMT.

Energy Balance Regulating Neuropeptides Are Expressed through Pregnancy and Regulated by Interleukin-6 Deficiency in Mouse Placenta.

PubMed

Pazos, Patricia; Lima, Luis; Diéguez, Carlos; García, María C

2014-01-01

The placenta produces a number of signaling molecules including metabolic and reproductive hormones as well as several inflammatory mediators. Among them, Interleukin-6 (IL-6), a well-known immune and metabolic regulator, acts peripherally modulating metabolic function and centrally increasing energy expenditure and reducing body fat. IL-6 interacts with key hypothalamic neuropeptidergic systems controlling energy homeostasis such as those producing the orexigenic/anabolic: neuropeptide Y (NPY) and agouti-related peptide (AgRP) and anorectic/catabolic neuropeptides: proopiomelanocortin (POMC) and cocaine and amphetamine regulated transcript (CART). Human and rat placenta have been identified as source of these neuropeptides, but their expression and regulation in murine placental tissues remain unknown. Therefore, placental mRNA levels of IL-6, NPY, AgRP, POMC, and CART at different pregnancy stages (gestational days 13, 15, and 18) were analyzed by real time PCR, as were the effect of IL-6 deficiency (IL-6 knockout mice) on their placental expression. Our results showed that placenta-derived neuropeptides were regulated by gestational age and IL-6 throughout the second half of mouse pregnancy. These data suggest that IL-6 may participate in the fine tune control of energy balance during pregnancy by extending its action as a metabolic signal to the main organ at the fetomaternal interface: the placenta.

How a mycoparasite employs g-protein signaling: using the example of trichoderma.

PubMed

Omann, Markus; Zeilinger, Susanne

2010-01-01

Mycoparasitic Trichoderma spp. act as potent biocontrol agents against a number of plant pathogenic fungi, whereupon the mycoparasitic attack includes host recognition followed by infection structure formation and secretion of lytic enzymes and antifungal metabolites leading to the host's death. Host-derived signals are suggested to be recognized by receptors located on the mycoparasite's cell surface eliciting an internal signal transduction cascade which results in the transcription of mycoparasitism-relevant genes. Heterotrimeric G proteins of fungi transmit signals originating from G-protein-coupled receptors mainly to the cAMP and the MAP kinase pathways resulting in regulation of downstream effectors. Components of the G-protein signaling machinery such as Gα subunits and G-protein-coupled receptors were recently shown to play crucial roles in Trichoderma mycoparasitism as they govern processes such as the production of extracellular cell wall lytic enzymes, the secretion of antifungal metabolites, and the formation of infection structures.

How a Mycoparasite Employs G-Protein Signaling: Using the Example of Trichoderma

PubMed Central

Omann, Markus; Zeilinger, Susanne

2010-01-01

Mycoparasitic Trichoderma spp. act as potent biocontrol agents against a number of plant pathogenic fungi, whereupon the mycoparasitic attack includes host recognition followed by infection structure formation and secretion of lytic enzymes and antifungal metabolites leading to the host's death. Host-derived signals are suggested to be recognized by receptors located on the mycoparasite's cell surface eliciting an internal signal transduction cascade which results in the transcription of mycoparasitism-relevant genes. Heterotrimeric G proteins of fungi transmit signals originating from G-protein-coupled receptors mainly to the cAMP and the MAP kinase pathways resulting in regulation of downstream effectors. Components of the G-protein signaling machinery such as Gα subunits and G-protein-coupled receptors were recently shown to play crucial roles in Trichoderma mycoparasitism as they govern processes such as the production of extracellular cell wall lytic enzymes, the secretion of antifungal metabolites, and the formation of infection structures. PMID:21637351

Platelet-derived growth factor-C and -D in the cardiovascular system and diseases.

PubMed

Lee, Chunsik; Li, Xuri

2018-08-01

The cardiovascular system is among the first organs formed during development and is pivotal for the formation and function of the rest of the organs and tissues. Therefore, the function and homeostasis of the cardiovascular system are finely regulated by many important molecules. Extensive studies have shown that platelet-derived growth factors (PDGFs) and their receptors are critical regulators of the cardiovascular system. Even though PDGF-C and PDGF-D are relatively new members of the PDGF family, their critical roles in the cardiovascular system as angiogenic and survival factors have been amply demonstrated. Understanding the functions of PDGF-C and PDGF-D and the signaling pathways involved may provide novel insights into both basic biomedical research and new therapeutic possibilities for the treatment of cardiovascular diseases. Copyright © 2017 Elsevier Ltd. All rights reserved.

Transcriptomic Analysis Reveals Wound Healing of Morus alba Root Extract by Up-Regulating Keratin Filament and CXCL12/CXCR4 Signaling.

PubMed

Kim, Kang-Hoon; Chung, Won-Seok; Kim, Yoomi; Kim, Ki-Suk; Lee, In-Seung; Park, Ji Young; Jeong, Hyeon-Soo; Na, Yun-Cheol; Lee, Chang-Hun; Jang, Hyeung-Jin

2015-08-01

Facilitation of the wound healing process is important because a prolonged wound site increases pain and the risk of infection. In oriental medicine, an extract of Morus alba root (MA) has usually been prescribed as traditional treatment for accelerating wound healing, and it has been proven to be safe for centuries. To study the molecular mechanism of MA-mediated skin wound healing, we performed a primary cell culture and a skin explant culture and observed significant difference between the groups with and without MA extract. In the cellular system, a real-time cell analysis and real-time quantitative PCR were performed. It was found that MA extract enhanced proliferation in a dose-dependent manner on Kera-308 cell line, and up-regulated keratin expression including wound-induced Krt6a. In skin explant culture, the mRNA level derived from cell outgrowth displayed a tendency toward more up-regulated mRNA associated keratin filaments and toward a more up-regulated mRNA level of C-X-C motif chemokine 12 (CXCL12) and a chemokine receptor 4 (CXCR4) axis signaling pathway downstream. In this process, we concluded that MA extract had a scientific possibility of wound repair by increasing intracellular and extracellular supports and by inducing a CXCL12/CXCR4 signaling pathway. Copyright © 2015 John Wiley & Sons, Ltd.

Primary Cilium-Regulated EG-VEGF Signaling Facilitates Trophoblast Invasion.

PubMed

Wang, Chia-Yih; Tsai, Hui-Ling; Syu, Jhih-Siang; Chen, Ting-Yu; Su, Mei-Tsz

2017-06-01

Trophoblast invasion is an important event in embryo implantation and placental development. During these processes, endocrine gland-derived vascular endothelial growth factor (EG-VEGF) is the key regulator mediating the crosstalk at the feto-maternal interface. The primary cilium is a cellular antenna receiving environmental signals and is crucial for proper development. However, little is known regarding the role of the primary cilium in early human pregnancy. Here, we demonstrate that EG-VEGF regulates trophoblast cell invasion via primary cilia. We found that EG-VEGF activated ERK1/2 signaling and subsequent upregulation of MMP2 and MMP9, thereby facilitating cell invasion in human trophoblast HTR-8/SVneo cells. Inhibition of ERK1/2 alleviated the expression of MMPs and trophoblast cell invasion after EG-VEGF treatment. In addition, primary cilia were observed in all the trophoblast cell lines tested and, more importantly, in human first-trimester placental tissue. The receptor of EG-VEGF, PROKR1, was detected in primary cilia. Depletion of IFT88, the intraflagellar transporter required for ciliogenesis, inhibited primary cilium growth, thereby ameliorating ERK1/2 activation, MMP upregulation, and trophoblast cell invasion promoted by EG-VEGF. These findings demonstrate a novel function of primary cilia in controlling EG-VEGF-regulated trophoblast invasion and reveal the underlying molecular mechanism. J. Cell. Physiol. 232: 1467-1477, 2017. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Genetic regulation of maize flower development and sex determination.

PubMed

Li, Qinglin; Liu, Baoshen

2017-01-01

The determining process of pistil fate are central to maize sex determination, mainly regulated by a genetic network in which the sex-determining genes SILKLESS 1 , TASSEL SEED 1 , TASSEL SEED 2 and the paramutagenic locus Required to maintain repression 6 play pivotal roles. Maize silks, which emerge from the ear shoot and derived from the pistil, are the functional stigmas of female flowers and play a pivotal role in pollination. Previous studies on sex-related mutants have revealed that sex-determining genes and phytohormones play an important role in the regulation of flower organogenesis. The processes determining pistil fate are central to flower development, where a silk identified gene SILKLESS 1 (SK1) is required to protect pistil primordia from a cell death signal produced by two commonly known genes, TASSEL SEED 1 (TS1) and TASSEL SEED 2 (TS2). In this review, maize flower developmental process is presented together with a focus on important sex-determining mutants and hormonal signaling affecting pistil development. The role of sex-determining genes, microRNAs, phytohormones, and the paramutagenic locus Required to maintain repression 6 (Rmr6), in forming a regulatory network that determines pistil fate, is discussed. Cloning SK1 and clarifying its function were crucial in understanding the regulation network of sex determination. The signaling mechanisms of phytohormones in sex determination are also an important research focus.

Absence of hyperplasia in Gasp-1 overexpressing mice is dependent on myostatin up-regulation.

PubMed

Brun, Caroline; Périé, Luce; Baraige, Fabienne; Vernus, Barbara; Bonnieu, Anne; Blanquet, Véronique

2014-01-01

Overexpression of Gasp-1, an inhibitor of myostatin, leads to a hypermuscular phenotype due to hypertrophy rather than hyperplasia in mice. However to date, the cellular and molecular mechanisms underlying this phenotype are not investigated. Skeletal muscles of overexpressing Gasp-1 mice, called Tg(Gasp-1) mice, were analyzed by histological methods. Satellite cell-derived myoblasts from these mice were used to investigate the molecular mechanisms. We demonstrated that hypertrophy in Tg(Gasp-1) mice was related to a myonuclear accretion during the first 3 postnatal weeks and an activation of the pro-hypertrophic Akt/mTORC/p70S6K signaling. In accordance with these results, we showed that overexpressing Gasp-1 primary myoblasts proliferated faster and myonuclei average per myotube was increased during differentiation. Molecular analysis revealed that Gasp-1 overexpression resulted in increased myostatin expression related to its auto-regulation. Despite its inhibition, myostatin led to Pax7 deregulation through its non-canonical Erk1/2 signaling pathway. Consistent with this, inhibition of Erk1/2 signaling pathway as well as neutralization of secreted myostatin rescue the Pax7 expression in overexpressing Gasp-1 myoblasts. Our study shows that myostatin is able to act independently of its canonical pathway to regulate the Pax7 expression. Altogether, our results indicate that myostatin could regulate muscle development despite its protein inhibition. © 2014 S. Karger AG, Basel.

Skeletal Muscle Function during Exercise—Fine-Tuning of Diverse Subsystems by Nitric Oxide

PubMed Central

Suhr, Frank; Gehlert, Sebastian; Grau, Marijke; Bloch, Wilhelm

2013-01-01

Skeletal muscle is responsible for altered acute and chronic workload as induced by exercise. Skeletal muscle adaptations range from immediate change of contractility to structural adaptation to adjust the demanded performance capacities. These processes are regulated by mechanically and metabolically induced signaling pathways, which are more or less involved in all of these regulations. Nitric oxide is one of the central signaling molecules involved in functional and structural adaption in different cell types. It is mainly produced by nitric oxide synthases (NOS) and by non-enzymatic pathways also in skeletal muscle. The relevance of a NOS-dependent NO signaling in skeletal muscle is underlined by the differential subcellular expression of NOS1, NOS2, and NOS3, and the alteration of NO production provoked by changes of workload. In skeletal muscle, a variety of highly relevant tasks to maintain skeletal muscle integrity and proper signaling mechanisms during adaptation processes towards mechanical and metabolic stimulations are taken over by NO signaling. The NO signaling can be mediated by cGMP-dependent and -independent signaling, such as S-nitrosylation-dependent modulation of effector molecules involved in contractile and metabolic adaptation to exercise. In this review, we describe the most recent findings of NO signaling in skeletal muscle with a special emphasis on exercise conditions. However, to gain a more detailed understanding of the complex role of NO signaling for functional adaptation of skeletal muscle (during exercise), additional sophisticated studies are needed to provide deeper insights into NO-mediated signaling and the role of non-enzymatic-derived NO in skeletal muscle physiology. PMID:23538841

NANOS2 acts downstream of glial cell line-derived neurotrophic factor signaling to suppress differentiation of spermatogonial stem cells.

PubMed

Sada, Aiko; Hasegawa, Kazuteru; Pin, Pui Han; Saga, Yumiko

2012-02-01

Stem cells are maintained by both stem cell-extrinsic niche signals and stem cell-intrinsic factors. During murine spermatogenesis, glial cell line-derived neurotrophic factor (GDNF) signal emanated from Sertoli cells and germ cell-intrinsic factor NANOS2 represent key regulators for the maintenance of spermatogonial stem cells. However, it remains unclear how these factors intersect in stem cells to control their cellular state. Here, we show that GDNF signaling is essential to maintain NANOS2 expression, and overexpression of Nanos2 can alleviate the stem cell loss phenotype caused by the depletion of Gfra1, a receptor for GDNF. By using an inducible Cre-loxP system, we show that NANOS2 expression is downregulated upon the conditional knockout (cKO) of Gfra1, while ectopic expression of Nanos2 in GFRA1-negative spermatogonia does not induce de novo GFRA1 expression. Furthermore, overexpression of Nanos2 in the Gfra1-cKO testes prevents precocious differentiation of the Gfra1-knockout stem cells and partially rescues the stem cell loss phenotypes of Gfra1-deficient mice, indicating that the stem cell differentiation can be suppressed by NANOS2 even in the absence of GDNF signaling. Taken together, we suggest that NANOS2 acts downstream of GDNF signaling to maintain undifferentiated state of spermatogonial stem cells. Copyright © 2011 AlphaMed Press.

BPN, a marine-derived PTP1B inhibitor, activates insulin signaling and improves insulin resistance in C2C12 myotubes.

PubMed

Xu, Qi; Luo, Jiao; Wu, Ning; Zhang, Renshuai; Shi, Dayong

2018-01-01

Insulin resistance is a key feature of type 2 diabetes mellitus (T2DM) and is characterized by defects in insulin signaling. Protein tyrosine phosphatase 1B (PTP1B) is a major negative regulator of insulin signaling cascade and has attracted intensive investigation in recent T2DM therapy study. BPN, a marine-derived bromophenol compound, was isolated from the red alga Rhodomela confervoides. This study investigated the effects of BPN on the insulin signaling pathway in insulin-resistant C2C12 myotubes by inhibiting PTP1B. Molecular docking study and analysis of small- molecule interaction with PTP1B all showed BPN inhibited PTP1B activity via binding to the catalytic site through hydrogen bonds. We then found that BPN permeated into C2C12 myotubes, on the one hand, activated insulin signaling in an insulin-independent manner in C2C12 cells; on the other hand, ameliorated palmitate-induced insulin resistance through augmenting insulin sensitivity. Moreover, our studies also showed that PTP1B inhibition by BPN increased glucose uptake in normal and insulin-resistant C2C12 myotubes through glucose transporter 4 (GLUT4) translocation. Taken together, BPN activates insulin signaling and alleviates insulin resistance and represents a potential candidate for further development as an antidiabetic agent. Copyright © 2017 Elsevier B.V. All rights reserved.

Brain-Derived Neurotrophic Factor Signaling Rewrites the Glucocorticoid Transcriptome via Glucocorticoid Receptor Phosphorylation

PubMed Central

Lambert, W. Marcus; Xu, Chong-Feng; Neubert, Thomas A.; Chao, Moses V.

2013-01-01

Abnormal glucocorticoid and neurotrophin signaling has been implicated in numerous psychiatric disorders. However, the impact of neurotrophic signaling on glucocorticoid receptor (GR)-dependent gene expression is not understood. We therefore examined the impact of brain-derived neurotrophic factor (BDNF) signaling on GR transcriptional regulatory function by gene expression profiling in primary rat cortical neurons stimulated with the selective GR agonist dexamethasone (Dex) and BDNF, alone or in combination. Simultaneous treatment with BDNF and Dex elicited a unique set of GR-responsive genes associated with neuronal growth and differentiation and also enhanced the induction of a large number of Dex-sensitive genes. BDNF via its receptor TrkB enhanced the transcriptional activity of a synthetic GR reporter, suggesting a direct effect of BDNF signaling on GR function. Indeed, BDNF treatment induces the phosphorylation of GR at serine 155 (S155) and serine 287 (S287). Expression of a nonphosphorylatable mutant (GR S155A/S287A) impaired the induction of a subset of BDNF- and Dex-regulated genes. Mechanistically, BDNF-induced GR phosphorylation increased GR occupancy and cofactor recruitment at the promoter of a BDNF-enhanced gene. GR phosphorylation in vivo is sensitive to changes in the levels of BDNF and TrkB as well as stress. Therefore, BDNF signaling specifies and amplifies the GR transcriptome through a coordinated GR phosphorylation-dependent detection mechanism. PMID:23878391

PI3K-mediated PDGFRα signaling regulates survival and proliferation in skeletal development through p53-dependent intracellular pathways

PubMed Central

Fantauzzo, Katherine A.; Soriano, Philippe

2014-01-01

Previous studies have identified phosphatidylinositol 3-kinase (PI3K) as the main downstream effector of PDGFRα signaling during murine skeletal development. Autophosphorylation mutant knock-in embryos in which PDGFRα is unable to bind PI3K (PdgfraPI3K/PI3K) exhibit skeletal defects affecting the palatal shelves, shoulder girdle, vertebrae, and sternum. To identify proteins phosphorylated by Akt downstream from PI3K-mediated PDGFRα signaling, we immunoprecipitated Akt phosphorylation substrates from PDGF-AA-treated primary mouse embryonic palatal mesenchyme (MEPM) lysates and analyzed the peptides by nanoliquid chromatography coupled to tandem mass spectrometry (nano-LC-MS/MS). Our analysis generated a list of 56 proteins, including 10 that regulate cell survival and proliferation. We demonstrate that MEPM cell survival is impaired in the presence of a PI3K inhibitor and that PdgfraPI3K/PI3K-derived MEPMs do not proliferate in response to PDGF-AA treatment. Several of the identified Akt phosphorylation targets, including Ybox1, mediate cell survival through regulation of p53. We show that Ybox1 binds both the Trp53 promoter and the p53 protein and that expression of Trp53 is significantly decreased upon PDGF-AA treatment in MEPMs. Finally, we demonstrate that introduction of a Trp53-null allele attenuates the vertebral defects found in PdgfraPI3K/PI3K neonates. Our findings identify p53 as a novel effector downstream from PI3K-engaged PDGFRα signaling that regulates survival and proliferation during skeletal development in vivo. PMID:24788519

Transcriptional Reversion of Cardiac Myocyte Fate During Mammalian Cardiac Regeneration

PubMed Central

O’Meara, Caitlin C.; Wamstad, Joseph A.; Gladstone, Rachel; Fomovsky, Gregory M.; Butty, Vincent L.; Shrikumar, Avanti; Gannon, Joseph; Boyer, Laurie A.; Lee, Richard T.

2014-01-01

Rationale Neonatal mice have the capacity to regenerate their hearts in response to injury, but this potential is lost after the first week of life. The transcriptional changes that underpin mammalian cardiac regeneration have not been fully characterized at the molecular level. Objective The objectives of our study were to determine if myocytes revert the transcriptional phenotype to a less differentiated state during regeneration and to systematically interrogate the transcriptional data to identify and validate potential regulators of this process. Methods and Results We derived a core transcriptional signature of injury-induced cardiac myocyte regeneration in mouse by comparing global transcriptional programs in a dynamic model of in vitro and in vivo cardiac myocyte differentiation, in vitro cardiac myocyte explant model, as well as a neonatal heart resection model. The regenerating mouse heart revealed a transcriptional reversion of cardiac myocyte differentiation processes including reactivation of latent developmental programs similar to those observed during de-stabilization of a mature cardiac myocyte phenotype in the explant model. We identified potential upstream regulators of the core network, including interleukin 13 (IL13), which induced cardiac myocyte cell cycle entry and STAT6/STAT3 signaling in vitro. We demonstrate that STAT3/periostin and STAT6 signaling are critical mediators of IL13 signaling in cardiac myocytes. These downstream signaling molecules are also modulated in the regenerating mouse heart. Conclusions Our work reveals new insights into the transcriptional regulation of mammalian cardiac regeneration and provides the founding circuitry for identifying potential regulators for stimulating heart regeneration. PMID:25477501

Role of Gab1 in Heart, Placenta, and Skin Development and Growth Factor- and Cytokine-Induced Extracellular Signal-Regulated Kinase Mitogen-Activated Protein Kinase Activation

PubMed Central

Itoh, Motoyuki; Yoshida, Yuichi; Nishida, Keigo; Narimatsu, Masahiro; Hibi, Masahiko; Hirano, Toshio

2000-01-01

Gab1 is a member of the Gab/DOS (Daughter of Sevenless) family of adapter molecules, which contain a pleckstrin homology (PH) domain and potential binding sites for SH2 and SH3 domains. Gab1 is tyrosine phosphorylated upon stimulation of various cytokines, growth factors, and antigen receptors in cell lines and interacts with signaling molecules, such as SHP-2 and phosphatidylinositol 3-kinase, although its biological roles have not yet been established. To reveal the functions of Gab1 in vivo, we generated mice lacking Gab1 by gene targeting. Gab1-deficient embryos died in utero and displayed developmental defects in the heart, placenta, and skin, which were similar to phenotypes observed in mice lacking signals of the hepatocyte growth factor/scatter factor, platelet-derived growth factor, and epidermal growth factor pathways. Consistent with these observations, extracellular signal-regulated kinase mitogen-activated protein (ERK MAP) kinases were activated at much lower levels in cells from Gab1-deficient embryos in response to these growth factors or to stimulation of the cytokine receptor gp130. These results indicate that Gab1 is a common player in a broad range of growth factor and cytokine signaling pathways linking ERK MAP kinase activation. PMID:10779359

Epithelial Control of Gut-Associated Lymphoid Tissue Formation through p38α-Dependent Restraint of NF-κB Signaling.

PubMed

Caballero-Franco, Celia; Guma, Monica; Choo, Min-Kyung; Sano, Yasuyo; Enzler, Thomas; Karin, Michael; Mizoguchi, Atsushi; Park, Jin Mo

2016-03-01

The protein kinase p38α mediates cellular responses to environmental and endogenous cues that direct tissue homeostasis and immune responses. Studies of mice lacking p38α in several different cell types have demonstrated that p38α signaling is essential to maintaining the proliferation-differentiation balance in developing and steady-state tissues. The mechanisms underlying these roles involve cell-autonomous control of signaling and gene expression by p38α. In this study, we show that p38α regulates gut-associated lymphoid tissue (GALT) formation in a noncell-autonomous manner. From an investigation of mice with intestinal epithelial cell-specific deletion of the p38α gene, we find that p38α serves to limit NF-κB signaling and thereby attenuate GALT-promoting chemokine expression in the intestinal epithelium. Loss of this regulation results in GALT hyperplasia and, in some animals, mucosa-associated B cell lymphoma. These anomalies occur independently of luminal microbial stimuli and are most likely driven by direct epithelial-lymphoid interactions. Our study illustrates a novel p38α-dependent mechanism preventing excessive generation of epithelial-derived signals that drive lymphoid tissue overgrowth and malignancy. Copyright © 2016 by The American Association of Immunologists, Inc.

An orthosteric inhibitor of the RAS-SOS interaction.

PubMed

Nickerson, Seth; Joy, Stephen T; Arora, Paramjit S; Bar-Sagi, Dafna

2013-01-01

Rat sarcoma (RAS) proteins are signaling nodes that transduce extracellular cues into precise alterations in cellular physiology by engaging effector pathways. RAS signaling thus regulates diverse cell processes including proliferation, migration, differentiation, and survival. Owing to this central role in governing mitogenic signals, RAS pathway components are often dysregulated in human diseases. Targeted therapy of RAS pathways has generally not been successful, largely because of the robust biochemistry of the targets and their multifaceted network of molecular regulators. The rate-limiting step of RAS activation is Son of Sevenless (SOS)-mediated nucleotide exchange involving a single evolutionarily conserved catalytic helix from SOS. Structure function data of this mechanism provided a strong platform to design an SOS-derived, helically constrained peptide mimic as an inhibitor of the RAS-SOS interaction. In this chapter, we review RAS-SOS signaling dynamics and present evidence supporting the novel paradigm of inhibiting their interaction as a therapeutic strategy. We then describe a method of generating helically constrained peptide mimics of protein surfaces, which we have employed to inhibit the RAS-SOS active site interaction. The biochemical and functional properties of this SOS mimic support the premise that inhibition of RAS-nucleotide exchange can effectively block RAS activation and downstream signaling. © 2013 Elsevier Inc. All rights reserved.

Shikonin derivatives inhibited LPS-induced NOS in RAW 264.7 cells via downregulation of MAPK/NF-kappaB signaling.

PubMed

Cheng, Yu Wen; Chang, Ching Yi; Lin, Kou Lung; Hu, Chien Ming; Lin, Cheng Hui; Kang, Jaw Jou

2008-11-20

Shikonin/alkannin (SA) derivatives, analogs of naphthoquinone pigments, are the major components of root extracts of the Chinese medicinal herb (Lithospermum erythrorhizon; LE) and widely distributed in several folk medicines. In the present study, the effect and the underline molecular mechanism of shikonin derivatives isolated from root extracts of Lithospermum euchroma on lipopolysaccharide (LPS)-induced inflammatory response were investigated. Effects of five SA derivatives, including SA, acetylshikonin, beta,beta-dimethylacrylshikonin, 5,8-dihydroxy-1.4-naphthoquinone, and 1,4-naphthoquinone on LPS-induced nitric oxide (NO) and prostaglandin E2 (PGE2) production in mouse macrophage RAW264.7 cells were examined. Data suggested that SA derivatives inhibited LPS-induced NO and PGE(2) production, and iNOS protein expression. RT-PCR analysis showed that SA derivatives diminished LPS-induced iNOS mRNA expression. Moreover, the phosphorylation of extracellular signal-regulated kinase (ERK)1/2 in LPS-stimulated RAW 264.7 cells was concentration-dependently suppressed by SA derivatives. SA inhibited NF-kappaB activation by prevention of the degradation of inhibitory factor-kappaB and p65 level in nuclear fractions induced by LPS. Taken together, these results suggest that the anti-inflammatory properties of SA derivatives might result from inhibition of iNOS protein expression through the downregulation of NF-kappaB activation via suppression of phosphorylation of ERK, in LPS-stimulated RAW 264.7 cells.

Tumor-derived exosomes regulate expression of immune function-related genes in human T cell subsets.

PubMed

Muller, Laurent; Mitsuhashi, Masato; Simms, Patricia; Gooding, William E; Whiteside, Theresa L

2016-02-04

Tumor cell-derived exosomes (TEX) suppress functions of immune cells. Here, changes in the gene profiles of primary human T lymphocytes exposed in vitro to exosomes were evaluated. CD4(+) Tconv, CD8(+) T or CD4(+) CD39(+) Treg were isolated from normal donors' peripheral blood and co-incubated with TEX or exosomes isolated from supernatants of cultured dendritic cells (DEX). Expression levels of 24-27 immune response-related genes in these T cells were quantified by qRT-PCR. In activated T cells, TEX and DEX up-regulated mRNA expression levels of multiple genes. Multifactorial data analysis of ΔCt values identified T cell activation and the immune cell type, but not exosome source, as factors regulating gene expression by exosomes. Treg were more sensitive to TEX-mediated effects than other T cell subsets. In Treg, TEX-mediated down-regulation of genes regulating the adenosine pathway translated into high expression of CD39 and increased adenosine production. TEX also induced up-regulation of inhibitory genes in CD4(+) Tconv, which translated into a loss of CD69 on their surface and a functional decline. Exosomes are not internalized by T cells, but signals they carry and deliver to cell surface receptors modulate gene expression and functions of human T lymphocytes.

Quantitative HRMAS proton total correlation spectroscopy applied to cultured melanoma cells treated by chloroethyl nitrosourea: demonstration of phospholipid metabolism alterations.

PubMed

Morvan, Daniel; Demidem, Aicha; Papon, Janine; Madelmont, Jean Claude

2003-02-01

Recent NMR spectroscopy developments, such as high-resolution magic angle spinning (HRMAS) probes and correlation-enhanced 2D sequences, now allow improved investigations of phospholipid (Plp) metabolism. Using these modalities we previously demonstrated that a mouse-bearing melanoma tumor responded to chloroethyl nitrosourea (CENU) treatment in vivo by altering its Plp metabolism. The aims of the present study were to investigate whether HRMAS proton total correlation spectroscopy (TOCSY) could be used as a quantitative technique to probe Plp metabolism, and to determine the Plp metabolism response of cultured B16 melanoma cells to CENU treatment in vitro. The exploited TOCSY signals of Plp derivatives arose from scalar coupling among the protons of neighbor methylene groups within base headgroups (choline and ethanolamine). For strongly expressed Plp derivatives, TOCSY signals were compared to saturation recovery signals and demonstrated a linear relationship. HRMAS proton TOCSY was thus used to provide concentrations of Plp derivatives during long-term follow-up of CENU-treated cell cultures. Strong Plp metabolism alteration was observed in treated cultured cells in vitro involving a down-regulation of phosphocholine, and a dramatic and irreversible increase of phosphoethanolamine. These findings are discussed in relation to previous in vivo data, and to Plp metabolism enzymatic involvement. Copyright 2003 Wiley-Liss, Inc.

Multiple myeloma-related deregulation of bone marrow-derived CD34(+) hematopoietic stem and progenitor cells.

PubMed

Bruns, Ingmar; Cadeddu, Ron-Patrick; Brueckmann, Ines; Fröbel, Julia; Geyh, Stefanie; Büst, Sebastian; Fischer, Johannes C; Roels, Frederik; Wilk, Christian Matthias; Schildberg, Frank A; Hünerlitürkoglu, Ali-Nuri; Zilkens, Christoph; Jäger, Marcus; Steidl, Ulrich; Zohren, Fabian; Fenk, Roland; Kobbe, Guido; Brors, Benedict; Czibere, Akos; Schroeder, Thomas; Trumpp, Andreas; Haas, Rainer

2012-09-27

Multiple myeloma (MM) is a clonal plasma cell disorder frequently accompanied by hematopoietic impairment. We show that hematopoietic stem and progenitor cells (HSPCs), in particular megakaryocyte-erythrocyte progenitors, are diminished in the BM of MM patients. Genomic profiling of HSPC subsets revealed deregulations of signaling cascades, most notably TGFβ signaling, and pathways involved in cytoskeletal organization, migration, adhesion, and cell-cycle regulation in the patients. Functionally, proliferation, colony formation, and long-term self-renewal were impaired as a consequence of activated TGFβ signaling. In accordance, TGFβ levels in the BM extracellular fluid were elevated and mesenchymal stromal cells (MSCs) had a reduced capacity to support long-term hematopoiesis of HSPCs that completely recovered on blockade of TGFβ signaling. Furthermore, we found defective actin assembly and down-regulation of the adhesion receptor CD44 in MM HSPCs functionally reflected by impaired migration and adhesion. Still, transplantation into myeloma-free NOG mice revealed even enhanced engraftment and normal differentiation capacities of MM HSPCs, which underlines that functional impairment of HSPCs depends on MM-related microenvironmental cues and is reversible. Taken together, these data implicate that hematopoietic suppression in MM emerges from the HSPCs as a result of MM-related microenvironmental alterations.

Diet and cognition: interplay between cell metabolism and neuronal plasticity

PubMed Central

Gomez-Pinilla, Fernando; Tyagi, Ethika

2014-01-01

Purpose of Study To discuss studies in humans and animals revealing the ability of foods to benefit the brain: new information with regards to mechanisms of action and the treatment of neurological and psychiatric disorders. Recent Findings Dietary factors exert their effects on the brain by affecting molecular events related to the management of energy metabolism and synaptic plasticity. Energy metabolism influences neuronal function, neuronal signaling, and synaptic plasticity, ultimately affecting mental health. Epigenetic regulation of neuronal plasticity appears as an important mechanism by which foods can prolong their effects on long term neuronal plasticity. Summary The prime focus of the discussion is to emphasize the role of cell metabolism as a mediator for the action of foods on the brain. Oxidative stress promotes damage to phospholipids present in the plasma membrane such as the omega-3 fatty acid DHA, disrupting neuronal signaling. Thus, dietary DHA seems crucial for supporting plasma membrane function, interneuronal signaling, and cognition. The dual action of brain-derived neurotrophic factor (BDNF) in neuronal metabolism and synaptic plasticity is crucial for activating signaling cascades under the action of diet and other environmental factors, using mechanisms of epigenetic regulation. PMID:24071781

The ER-mitochondria interface: the social network of cell death.

PubMed

Grimm, Stefan

2012-02-01

When cellular organelles communicate bad things can happen. Recent findings uncovered that the junction between the endoplasmic reticulum (ER) and the mitochondria holds a crucial role for cell death regulation. Not only does this locale connect the two best-known organelles in apoptosis, numerous regulators of cell death are concentrated at this spot, providing a terrain for intense signal transfers. Ca2+ is the most prominent signalling factor that is released from the ER and, at high concentration, mediates the transfer of an apoptosis signal to mitochondria as the executioner organelle for cell death. An elaborate array of checks and balances is fine-tuning this process including Bcl-2 family members. Moreover, MAMs, "mitochondria-associated membranes", are distinct membrane sections at the ER that are in close contact with mitochondria and have been found to exchange lipids and lipid-derived molecules such as ceramide for apoptosis induction. Recent work has also described a reverse transfer of apoptosis signals, from mitochondria to the ER, via cytochrome c release and prolonged IP3R opening or through the mitochondrial fission factor Fis1 and Bap31 at the ER, which form the ARCosome, a novel caspase-activation complex. Copyright © 2011 Elsevier B.V. All rights reserved.

Signaling hierarchy regulating human endothelial cell development.

PubMed

Kelly, Melissa A; Hirschi, Karen K

2009-05-01

Our present knowledge of the regulation of mammalian endothelial cell differentiation has been largely derived from studies of mouse embryonic development. However, unique mechanisms and hierarchy of signals that govern human endothelial cell development are unknown and, thus, explored in these studies. Using human embryonic stem cells as a model system, we were able to reproducibly and robustly generate differentiated endothelial cells via coculture on OP9 marrow stromal cells. We found that, in contrast to studies in the mouse, bFGF and VEGF had no specific effects on the initiation of human vasculogenesis. However, exogenous Ihh promoted endothelial cell differentiation, as evidenced by increased production of cells with cobblestone morphology that coexpress multiple endothelial-specific genes and proteins, form lumens, and exhibit DiI-AcLDL uptake. Inhibition of BMP signaling using Noggin or BMP4, specifically, using neutralizing antibodies suppressed endothelial cell formation; whereas, addition of rhBMP4 to cells treated with the hedgehog inhibitor cyclopamine rescued endothelial cell development. Our studies revealed that Ihh promoted human endothelial cell differentiation from pluripotent hES cells via BMP signaling, providing novel insights applicable to modulating human endothelial cell formation and vascular regeneration for human clinical therapies.

Sonic hedgehog signaling in spinal cord contributes to morphine-induced hyperalgesia and tolerance through upregulating brain-derived neurotrophic factor expression

PubMed Central

Song, Zhi-Jing; Miao, Shuai; Zhao, Ye; Wang, Xiu-Li; Liu, Yue-Peng

2018-01-01

Purpose Preventing opioid-induced hyperalgesia and tolerance continues to be a major clinical challenge, and the underlying mechanisms of hyperalgesia and tolerance remain elusive. Here, we investigated the role of sonic hedgehog (Shh) signaling in opioid-induced hyperalgesia and tolerance. Methods Shh signaling expression, behavioral changes, and neurochemical alterations induced by morphine were analyzed in male adult CD-1 mice with repeated administration of morphine. To investigate the contribution of Shh to morphine-induced hyperalgesia (MIH) and tolerance, Shh signaling inhibitor cyclopamine and Shh small interfering RNA (siRNA) were used. To explore the mechanisms of Shh signaling in MIH and tolerance, brain-derived neurotrophic factor (BDNF) inhibitor K252 and anti-BDNF antibody were used. Results Repeated administration of morphine produced obvious hyperalgesia and tolerance. The behavioral changes were correlated with the upregulation and activation of morphine treatment-induced Shh signaling. Pharmacologic and genetic inhibition of Shh signaling significantly delayed the generation of MIH and tolerance and associated neurochemical changes. Chronic morphine administration also induced upregulation of BDNF. Inhibiting BDNF effectively delayed the generation of MIH and tolerance. The upregulation of BDNF induced by morphine was significantly suppressed by inhibiting Shh signaling. In naïve mice, exogenous activation of Shh signaling caused a rapid increase of BDNF expression, as well as thermal hyperalgesia. Inhibiting BDNF significantly suppressed smoothened agonist-induced hyperalgesia. Conclusion These findings suggest that Shh signaling may be a critical mediator for MIH and tolerance by regulating BDNF expression. Inhibiting Shh signaling, especially during the early phase, may effectively delay or suppress MIH and tolerance. PMID:29662325

A maize death acid, 10-oxo-11-phytoenoic acid, is the predominant cyclopentenone signal present during multiple stress and developmental conditions

PubMed Central

Christensen, Shawn A.; Huffaker, Alisa; Hunter, Charles T.; Alborn, Hans T.; Schmelz, Eric A.

2016-01-01

abstract Recently we investigated the function of the 9-lipoxygenase (LOX) derived cyclopentenones 10-oxo-11-phytoenoic acid (10-OPEA) and 10-oxo-11,15-phytodienoic acid (10-OPDA) and identified their C-14 and C-12 derivatives. 10-OPEA accumulation is elicited by fungal and insect attack and acts as a strong inhibitor of microbial and herbivore growth. Although structurally similar, comparative analyses between 10-OPEA and its 13-LOX analog 12-oxo-phytodienoic acid (12-OPDA) demonstrate specificity in transcript accumulation linked to detoxification, secondary metabolism, jasmonate regulation, and protease inhibition. As a potent cell death signal, 10-OPEA activates cysteine protease activity leading to ion leakage and apoptotic-like DNA fragmentation. In this study we further elucidate the distribution, abundance, and functional roles of 10-OPEA, 10-OPDA, and 12-OPDA, in diverse organs under pathogen- and insect-related stress. PMID:26669723

Ghrelin-Derived Peptides: A Link between Appetite/Reward, GH Axis, and Psychiatric Disorders?

PubMed Central

Labarthe, Alexandra; Fiquet, Oriane; Hassouna, Rim; Zizzari, Philippe; Lanfumey, Laurence; Ramoz, Nicolas; Grouselle, Dominique; Epelbaum, Jacques; Tolle, Virginie

2014-01-01

Psychiatric disorders are often associated with metabolic and hormonal alterations, including obesity, diabetes, metabolic syndrome as well as modifications in several biological rhythms including appetite, stress, sleep–wake cycles, and secretion of their corresponding endocrine regulators. Among the gastrointestinal hormones that regulate appetite and adapt the metabolism in response to nutritional, hedonic, and emotional dysfunctions, at the interface between endocrine, metabolic, and psychiatric disorders, ghrelin plays a unique role as the only one increasing appetite. The secretion of ghrelin is altered in several psychiatric disorders (anorexia, schizophrenia) as well as in metabolic disorders (obesity) and in animal models in response to emotional triggers (psychological stress …) but the relationship between these modifications and the physiopathology of psychiatric disorders remains unclear. Recently, a large literature showed that this key metabolic/endocrine regulator is involved in stress and reward-oriented behaviors and regulates anxiety and mood. In addition, preproghrelin is a complex prohormone but the roles of the other ghrelin-derived peptides, thought to act as functional ghrelin antagonists, are largely unknown. Altered ghrelin secretion and/or signaling in psychiatric diseases are thought to participate in altered appetite, hedonic response and reward. Whether this can contribute to the mechanism responsible for the development of the disease or can help to minimize some symptoms associated with these psychiatric disorders is discussed in the present review. We will thus describe (1) the biological actions of ghrelin and ghrelin-derived peptides on food and drugs reward, anxiety and depression, and the physiological consequences of ghrelin invalidation on these parameters, (2) how ghrelin and ghrelin-derived peptides are regulated in animal models of psychiatric diseases and in human psychiatric disorders in relation with the GH axis. PMID:25386163

Retrograde Semaphorin-Plexin Signaling Drives Homeostatic Synaptic Plasticity

PubMed Central

Orr, Brian O.; Fetter, Richard D.; Davis, Graeme W.

2017-01-01

Homeostatic signaling systems ensure stable, yet flexible neural activity and animal behavior1–4. Defining the underlying molecular mechanisms of neuronal homeostatic signaling will be essential in order to establish clear connections to the causes and progression of neurological disease. Presynaptic homeostatic plasticity (PHP) is a conserved form of neuronal homeostatic signaling, observed in organisms ranging from Drosophila to human1,5. Here, we demonstrate that Semaphorin2b (Sema2b) is target-derived signal that acts upon presynaptic PlexinB (PlexB) receptors to mediate the retrograde, homeostatic control of presynaptic neurotransmitter release at the Drosophila neuromuscular junction. Sema2b-PlexB signaling regulates the expression of PHP via the cytoplasmic protein Mical and the oxoreductase-dependent control of presynaptic actin6,7. During neural development, Semaphorin-Plexin signaling instructs axon guidance and neuronal morphogenesis8–10. Yet, Semaphorins and Plexins are also expressed in the adult brain11–16. Here we demonstrate that Semaphorin-Plexin signaling controls presynaptic neurotransmitter release. We propose that Sema2b-PlexB signaling is an essential platform for the stabilization of synaptic transmission throughout life. PMID:28953869

Hardware Model of a Shipboard Generator

DTIC Science & Technology

2009-05-19

controller output PM motor power RM motor resistance Td derivative time constant Tf1 fuel valve time constant Tg1 governor time constant Tg2 governor...in speed, sending a response signal to the fuel valve that regulates gas turbine power. At this point, there is an inherent variation between the...basic response analysis [5]. 29 Electrical Power Rotor Inertia Amplifiers Fuel Valve Turbine Dynamics Rotational Friction and Windage

mTOR signaling plays a critical role in the defects observed in muscle-derived stem/progenitor cells isolated from a murine model of accelerated aging.

PubMed

Takayama, Koji; Kawakami, Yohei; Lavasani, Mitra; Mu, Xiaodong; Cummins, James H; Yurube, Takashi; Kuroda, Ryosuke; Kurosaka, Masahiro; Fu, Freddie H; Robbins, Paul D; Niedernhofer, Laura J; Huard, Johnny

2017-07-01

Mice expressing reduced levels of ERCC1-XPF (Ercc1 -/Δ mice) demonstrate premature onset of age-related changes due to decreased repair of DNA damage. Muscle-derived stem/progenitor cells (MDSPCs) isolated from Ercc1 -/Δ mice have an impaired capacity for cell differentiation. The mammalian target of rapamycin (mTOR) is a critical regulator of cell growth in response to nutrient, hormone, and oxygen levels. Inhibition of the mTOR pathway extends the lifespan of several species. Here, we examined the role of mTOR in regulating the MDSPC dysfunction that occurs with accelerated aging. We show that mTOR signaling pathways are activated in Ercc1 -/Δ MDSPCs compared with wild-type (WT) MDSPCs. Additionally, inhibiting mTOR with rapamycin promoted autophagy and improved the myogenic differentiation capacity of the Ercc1 -/Δ MDSPCs. The percent of apoptotic and senescent cells in Ercc1 -/Δ MDSPC cultures was decreased upon mTOR inhibition. These results establish that mTOR signaling contributes to stem cell dysfunction and cell fate decisions in response to endogenous DNA damage. Therefore, mTOR represents a potential therapeutic target for improving defective, aged stem cells. © 2016 The Authors. Journal of Orthopaedic Research Published by Wiley Periodicals, Inc. on behalf of Orthopaedic Research Society. J Orthop Res 35:1375-1382, 2017. © 2016 The Authors. Journal of Orthopaedic Research Published by Wiley Periodicals, Inc. on behalf of Orthopaedic Research Society.

Nox2-derived ROS in PPARγ signaling and cell-cycle progression of lung alveolar epithelial cells

PubMed Central

Tickner, Jennifer; Fan, Lampson M.; Du, Junjie; Meijles, Daniel; Li, Jian-Mei

2011-01-01

Reactive oxygen species (ROS) play important roles in peroxisome proliferator-activated receptor γ (PPARγ) signaling and cell-cycle regulation. However, the PPARγ redox-signaling pathways in lung alveolar epithelial cells remain unclear. In this study, we investigated the in vivo and in vitro effects of PPARγ activation on the levels of lung ROS production and cell-cycle progression using C57BL/6J wild-type and Nox2 knockout mice (n = 10) after intraperitoneal injection of a selective PPARγ agonist (GW1929, 5 mg/kg body wt, daily) for 14 days. Compared to vehicle-treated mice, GW1929 increased significantly the levels of ROS production in wild-type lungs, and this was accompanied by significant up-regulation of PPARγ, Nox2, PCNA, and cyclin D1 and phosphorylation of ERK1/2 and p38MAPK. These effects were absent in Nox2 knockout mice. In cultured alveolar epithelial cells, GW1929 (5 μM for 24 h) increased ROS production and promoted cell-cycle progression from G0/G1 into S and G2/M phases, and these effects were abolished by (1) adding a PPARγ antagonist (BADGE, 1 μM), (2) knockdown of PPARγ using siRNA, or (3) knockout of Nox2. In conclusion, PPARγ activation through Nox2-derived ROS promotes cell-cycle progression in normal mouse lungs and in cultured normal alveolar epithelial cells. PMID:21664456

Neurotrophin Signaling via Long-Distance Axonal Transport

NASA Astrophysics Data System (ADS)

Chowdary, Praveen D.; Che, Dung L.; Cui, Bianxiao

2012-05-01

Neurotrophins are a family of target-derived growth factors that support survival, development, and maintenance of innervating neurons. Owing to the unique architecture of neurons, neurotrophins that act locally on the axonal terminals must convey their signals across the entire axon for subsequent regulation of gene transcription in the cell nucleus. This long-distance retrograde signaling, a motor-driven process that can take hours or days, has been a subject of intense interest. In the last decade, live-cell imaging with high sensitivity has significantly increased our capability to track the transport of neurotrophins, their receptors, and subsequent signals in real time. This review summarizes recent research progress in understanding neurotrophin-receptor interactions at the axonal terminal and their transport dynamics along the axon. We emphasize high-resolution studies at the single-molecule level and also discuss recent technical advances in the field.

Critical role for ERK1/2 in bone marrow and fetal liver–derived primary megakaryocyte differentiation, motility, and proplatelet formation

PubMed Central

Mazharian, Alexandra; Watson, Steve P.; Séverin, Sonia

2009-01-01

Objective Megakaryopoiesis and platelet formation is a multistep process through which hematopoietic progenitor cells develop into mature megakaryocytes (MKs) and form proplatelets. The present study investigates the regulation of different steps of megakaryopoiesis (i.e., differentiation, migration, and proplatelet formation) by extracellar signal-regulated kinase (ERK)1/2 and p38 mitogen-activated protein kinase (MAPK) in two models of primary murine MKs derived from bone marrow (BM) cells and fetal liver (FL) cells. Materials and Methods A preparation of MKs was generated from BM obtained from femora and tibiae of C57BL6 mice. FL-derived MKs were obtained from the liver of mouse fetuses aged 13 to 15 days. Results For both cell populations, activation of MEK-ERK1/2 pathway by thrombopoietin was found to have a critical role in MK differentiation, regulating polyploidy and surface expression of CD34, GPIIb, and GPIb. The MEK-ERK1/2 pathway plays a major role in migration of BM-derived MKs toward a stromal-cell−derived factor 1α (SDF1α) gradient, whereas unexpectedly, FL-derived cells fail to migrate in response to the chemokine due to negligible expression of its receptor, CXCR4. The MEK-ERK1/2 pathway also plays a critical role in the generation of proplatelets. In contrast, p38MAPK pathway was not involved in any of these processes. Conclusion This report demonstrates a critical role of MEK-ERK1/2 pathway in MK differentiation, motility, and proplatelet formation. This study highlights several differences between BM- and FL-derived MKs, which are discussed. PMID:19619605

Hemidesmosomal linker proteins regulate cell motility, invasion and tumorigenicity in oral squamous cell carcinoma derived cells.

PubMed

Chaudhari, Pratik Rajeev; Charles, Silvania Emlit; D'Souza, Zinia Charlotte; Vaidya, Milind Murlidhar

2017-11-15

BPAG1e and Plectin are hemidesmosomal linker proteins which anchor intermediate filament proteins to the cell surface through β4 integrin. Recent reports indicate that these proteins play a role in various cellular processes apart from their known anchoring function. However, the available literature is inconsistent. Further, the previous study from our laboratory suggested that Keratin8/18 pair promotes cell motility and tumor progression by deregulating β4 integrin signaling in oral squamous cell carcinoma (OSCC) derived cells. Based on these findings, we hypothesized that linker proteins may have a role in neoplastic progression of OSCC. Downregulation of hemidesmosomal linker proteins in OSCC derived cells resulted in reduced cell migration accompanied by alterations in actin organization. Further, decreased MMP9 activity led to reduced cell invasion in linker proteins knockdown cells. Moreover, loss of these proteins resulted in reduced tumorigenic potential. SWATH analysis demonstrated upregulation of N-Myc downstream regulated gene 1 (NDRG1) in linker proteins downregulated cells as compared to vector control cells. Further, the defects in phenotype upon linker proteins ablation were rescued upon loss of NDRG1 in linker proteins knockdown background. These data together indicate that hemidesmosomal linker proteins regulate cell motility, invasion and tumorigenicity possibly through NDRG1 in OSCC derived cells. Copyright © 2017 Elsevier Inc. All rights reserved.

Potential of cancer cell-derived exosomes in clinical application: a review of recent research advances.

PubMed

Sun, Yu; Liu, Jing

2014-06-01

Exosomes are 30- to 100-nm, membrane-bound vesicles that are released by most types of cells, including tumor cells. Exosomes contain a great variety of bioactive molecules, including signal peptides, microRNA, lipids, and DNA. In cancer, tumor cells aberrantly secrete large quantities of exosomes to transport paracrine signals or to contribute to tumor-environment interaction at a distance. The goal of this review was to discuss the recent advances on the mechanism of cancer-derived exosomes in tumor regulation. Pertinent articles and abstracts were identified through searches of PubMed for literature published from 1983 to December 2013. Search terms included exosome, tumor, cancer, diagnosis, and therapy. All of the exposed evidence points to communication between cancer cells and their surroundings, either mediated by cancer cell-derived exosomes or by stromal cell-derived exosomes. This communication probably supports tumor proliferation, motility, invasion, angiogenesis, and premetastatic niche preparation. In addition, recent research implies that cancer cell-derived exosomes play a suppressive role in cancer-directed immune response. The biomarkers detected in bodily fluid-derived exosomes imply a potential for exosomes in cancer diagnosis. Also, exosomes could be used as a vehicle to selectively deliver therapeutic nucleic-acid drugs or conventional drugs for tumor therapy. The tolerability and feasibility of cancer exosomes in diagnosis and therapy need to be further evaluated. Copyright © 2014 Elsevier HS Journals, Inc. All rights reserved.

Requirement of Smad4 from Ocular Surface Ectoderm for Retinal Development.

PubMed

Li, Jing; Wang, Shusheng; Anderson, Chastain; Zhao, Fangkun; Qin, Yu; Wu, Di; Wu, Xinwei; Liu, Jia; He, Xuefei; Zhao, Jiangyue; Zhang, Jinsong

2016-01-01

Microphthalmia is characterized by abnormally small eyes and usually retinal dysplasia, accounting for up to 11% of the blindness in children. Right now there is no effective treatment for the disease, and the underlying mechanisms, especially how retinal dysplasia develops from microphthalmia and whether it depends on the signals from lens ectoderm are still unclear. Mutations in genes of the TGF-β superfamily have been noted in patients with microphthalmia. Using conditional knockout mice, here we address the question that whether ocular surface ectoderm-derived Smad4 modulates retinal development. We found that loss of Smad4 specifically on surface lens ectoderm leads to microphthalmia and dysplasia of retina. Retinal dysplasia in the knockout mice is caused by the delayed or failed differentiation and apoptosis of retinal cells. Microarray analyses revealed that members of Hedgehog and Wnt signaling pathways are affected in the knockout retinas, suggesting that ocular surface ectoderm-derived Smad4 can regulate Hedgehog and Wnt signaling in the retina. Our studies suggest that defective of ocular surface ectoderm may affect retinal development.

Requirement of Smad4 from Ocular Surface Ectoderm for Retinal Development

PubMed Central

Li, Jing; Wang, Shusheng; Anderson, Chastain; Zhao, Fangkun; Qin, Yu; Wu, Di; Wu, Xinwei; Liu, Jia; He, Xuefei; Zhao, Jiangyue; Zhang, Jinsong

2016-01-01

Microphthalmia is characterized by abnormally small eyes and usually retinal dysplasia, accounting for up to 11% of the blindness in children. Right now there is no effective treatment for the disease, and the underlying mechanisms, especially how retinal dysplasia develops from microphthalmia and whether it depends on the signals from lens ectoderm are still unclear. Mutations in genes of the TGF-β superfamily have been noted in patients with microphthalmia. Using conditional knockout mice, here we address the question that whether ocular surface ectoderm-derived Smad4 modulates retinal development. We found that loss of Smad4 specifically on surface lens ectoderm leads to microphthalmia and dysplasia of retina. Retinal dysplasia in the knockout mice is caused by the delayed or failed differentiation and apoptosis of retinal cells. Microarray analyses revealed that members of Hedgehog and Wnt signaling pathways are affected in the knockout retinas, suggesting that ocular surface ectoderm-derived Smad4 can regulate Hedgehog and Wnt signaling in the retina. Our studies suggest that defective of ocular surface ectoderm may affect retinal development. PMID:27494603

Genetic fine-mapping and genomic annotation defines causal mechanisms at type 2 diabetes susceptibility loci

PubMed Central

Mahajan, Anubha; Locke, Adam; Rayner, N William; Robertson, Neil; Scott, Robert A; Prokopenko, Inga; Scott, Laura J; Green, Todd; Sparso, Thomas; Thuillier, Dorothee; Yengo, Loic; Grallert, Harald; Wahl, Simone; Frånberg, Mattias; Strawbridge, Rona J; Kestler, Hans; Chheda, Himanshu; Eisele, Lewin; Gustafsson, Stefan; Steinthorsdottir, Valgerdur; Thorleifsson, Gudmar; Qi, Lu; Karssen, Lennart C; van Leeuwen, Elisabeth M; Willems, Sara M; Li, Man; Chen, Han; Fuchsberger, Christian; Kwan, Phoenix; Ma, Clement; Linderman, Michael; Lu, Yingchang; Thomsen, Soren K; Rundle, Jana K; Beer, Nicola L; van de Bunt, Martijn; Chalisey, Anil; Kang, Hyun Min; Voight, Benjamin F; Abecasis, Goncalo R; Almgren, Peter; Baldassarre, Damiano; Balkau, Beverley; Benediktsson, Rafn; Blüher, Matthias; Boeing, Heiner; Bonnycastle, Lori L; Borringer, Erwin P; Burtt, Noël P; Carey, Jason; Charpentier, Guillaume; Chines, Peter S; Cornelis, Marilyn C; Couper, David J; Crenshaw, Andrew T; van Dam, Rob M; Doney, Alex SF; Dorkhan, Mozhgan; Edkins, Sarah; Eriksson, Johan G; Esko, Tonu; Eury, Elodie; Fadista, João; Flannick, Jason; Fontanillas, Pierre; Fox, Caroline; Franks, Paul W; Gertow, Karl; Gieger, Christian; Gigante, Bruna; Gottesman, Omri; Grant, George B; Grarup, Niels; Groves, Christopher J; Hassinen, Maija; Have, Christian T; Herder, Christian; Holmen, Oddgeir L; Hreidarsson, Astradur B; Humphries, Steve E; Hunter, David J; Jackson, Anne U; Jonsson, Anna; Jørgensen, Marit E; Jørgensen, Torben; Kerrison, Nicola D; Kinnunen, Leena; Klopp, Norman; Kong, Augustine; Kovacs, Peter; Kraft, Peter; Kravic, Jasmina; Langford, Cordelia; Leander, Karin; Liang, Liming; Lichtner, Peter; Lindgren, Cecilia M; Lindholm, Eero; Linneberg, Allan; Liu, Ching-Ti; Lobbens, Stéphane; Luan, Jian’an; Lyssenko, Valeriya; Männistö, Satu; McLeod, Olga; Meyer, Julia; Mihailov, Evelin; Mirza, Ghazala; Mühleisen, Thomas W; Müller-Nurasyid, Martina; Navarro, Carmen; Nöthen, Markus M; Oskolkov, Nikolay N; Owen, Katharine R; Palli, Domenico; Pechlivanis, Sonali; Perry, John RB; Platou, Carl GP; Roden, Michael; Ruderfer, Douglas; Rybin, Denis; van der Schouw, Yvonne T; Sennblad, Bengt; Sigurðsson, Gunnar; Stančáková, Alena; Steinbach, Gerald; Storm, Petter; Strauch, Konstantin; Stringham, Heather M; Sun, Qi; Thorand, Barbara; Tikkanen, Emmi; Tonjes, Anke; Trakalo, Joseph; Tremoli, Elena; Tuomi, Tiinamaija; Wennauer, Roman; Wood, Andrew R; Zeggini, Eleftheria; Dunham, Ian; Birney, Ewan; Pasquali, Lorenzo; Ferrer, Jorge; Loos, Ruth JF; Dupuis, Josée; Florez, Jose C; Boerwinkle, Eric; Pankow, James S; van Duijn, Cornelia; Sijbrands, Eric; Meigs, James B; Hu, Frank B; Thorsteinsdottir, Unnur; Stefansson, Kari; Lakka, Timo A; Rauramaa, Rainer; Stumvoll, Michael; Pedersen, Nancy L; Lind, Lars; Keinanen-Kiukaanniemi, Sirkka M; Korpi-Hyövälti, Eeva; Saaristo, Timo E; Saltevo, Juha; Kuusisto, Johanna; Laakso, Markku; Metspalu, Andres; Erbel, Raimund; Jöckel, Karl-Heinz; Moebus, Susanne; Ripatti, Samuli; Salomaa, Veikko; Ingelsson, Erik; Boehm, Bernhard O; Bergman, Richard N; Collins, Francis S; Mohlke, Karen L; Koistinen, Heikki; Tuomilehto, Jaakko; Hveem, Kristian; Njølstad, Inger; Deloukas, Panagiotis; Donnelly, Peter J; Frayling, Timothy M; Hattersley, Andrew T; de Faire, Ulf; Hamsten, Anders; Illig, Thomas; Peters, Annette; Cauchi, Stephane; Sladek, Rob; Froguel, Philippe; Hansen, Torben; Pedersen, Oluf; Morris, Andrew D; Palmer, Collin NA; Kathiresan, Sekar; Melander, Olle; Nilsson, Peter M; Groop, Leif C; Barroso, Inês; Langenberg, Claudia; Wareham, Nicholas J; O’Callaghan, Christopher A; Gloyn, Anna L; Altshuler, David; Boehnke, Michael; Teslovich, Tanya M; McCarthy, Mark I; Morris, Andrew P

2015-01-01

We performed fine-mapping of 39 established type 2 diabetes (T2D) loci in 27,206 cases and 57,574 controls of European ancestry. We identified 49 distinct association signals at these loci, including five mapping in/near KCNQ1. “Credible sets” of variants most likely to drive each distinct signal mapped predominantly to non-coding sequence, implying that T2D association is mediated through gene regulation. Credible set variants were enriched for overlap with FOXA2 chromatin immunoprecipitation binding sites in human islet and liver cells, including at MTNR1B, where fine-mapping implicated rs10830963 as driving T2D association. We confirmed that this T2D-risk allele increases FOXA2-bound enhancer activity in islet- and liver-derived cells. We observed allele-specific differences in NEUROD1 binding in islet-derived cells, consistent with evidence that the T2D-risk allele increases islet MTNR1B expression. Our study demonstrates how integration of genetic and genomic information can define molecular mechanisms through which variants underlying association signals exert their effects on disease. PMID:26551672

Required, tissue-specific roles for Fgf8 in outflow tract formation and remodeling.

PubMed

Park, Eon Joo; Ogden, Lisa A; Talbot, Amy; Evans, Sylvia; Cai, Chen-Leng; Black, Brian L; Frank, Deborah U; Moon, Anne M

2006-06-01

Fibroblast growth factor 8 (Fgf8) is a secreted signaling protein expressed in numerous temporospatial domains that are potentially relevant to cardiovascular development. However, the pathogenesis of complex cardiac and outflow tract defects observed in Fgf8-deficient mice, and the specific source(s) of Fgf8 required for outflow tract formation and subsequent remodeling are unknown. A detailed examination of the timing and location of Fgf8 production revealed previously unappreciated expression in a subset of primary heart field cells; Fgf8 is also expressed throughout the anterior heart field (AHF) mesoderm and in pharyngeal endoderm at the crescent and early somite stages. We used conditional mutagenesis to examine the requirements for Fgf8 function in these different expression domains during heart and outflow tract morphogenesis. Formation of the primary heart tube and the addition of right ventricular and outflow tract myocardium depend on autocrine Fgf8 signaling in cardiac crescent mesoderm. Loss of Fgf8 in this domain resulted in decreased expression of the Fgf8 target gene Erm, and aberrant production of Isl1 and its target Mef2c in the anterior heart field, thus linking Fgf8 signaling with transcription factor networks that regulate survival and proliferation of the anterior heart field. We further found that mesodermal- and endodermal-derived Fgf8 perform specific functions during outflow tract remodeling: mesodermal Fgf8 is required for correct alignment of the outflow tract and ventricles, whereas activity of Fgf8 emanating from pharyngeal endoderm regulates outflow tract septation. These findings provide a novel insight into how the formation and remodeling of primary and anterior heart field-derived structures rely on Fgf8 signals from discrete temporospatial domains.

NOS1-derived nitric oxide promotes NF-κB transcriptional activity through inhibition of suppressor of cytokine signaling-1

PubMed Central

Baig, Mirza Saqib; Zaichick, Sofia V.; Mao, Mao; de Abreu, Andre L.; Bakhshi, Farnaz R.; Hart, Peter C.; Saqib, Uzma; Deng, Jing; Chatterjee, Saurabh; Block, Michelle L.; Vogel, Stephen M.; Malik, Asrar B.; Consolaro, Marcia E.L.; Christman, John W.; Minshall, Richard D.

2015-01-01

The NF-κB pathway is central to the regulation of inflammation. Here, we demonstrate that the low-output nitric oxide (NO) synthase 1 (NOS1 or nNOS) plays a critical role in the inflammatory response by promoting the activity of NF-κB. Specifically, NOS1-derived NO production in macrophages leads to proteolysis of suppressor of cytokine signaling 1 (SOCS1), alleviating its repression of NF-κB transcriptional activity. As a result, NOS1−/− mice demonstrate reduced cytokine production, lung injury, and mortality when subjected to two different models of sepsis. Isolated NOS1−/− macrophages demonstrate similar defects in proinflammatory transcription on challenge with Gram-negative bacterial LPS. Consistently, we found that activated NOS1−/− macrophages contain increased SOCS1 protein and decreased levels of p65 protein compared with wild-type cells. NOS1-dependent S-nitrosation of SOCS1 impairs its binding to p65 and targets SOCS1 for proteolysis. Treatment of NOS1−/− cells with exogenous NO rescues both SOCS1 degradation and stabilization of p65 protein. Point mutation analysis demonstrated that both Cys147 and Cys179 on SOCS1 are required for its NO-dependent degradation. These findings demonstrate a fundamental role for NOS1-derived NO in regulating TLR4-mediated inflammatory gene transcription, as well as the intensity and duration of the resulting host immune response. PMID:26324446

Postsynaptic localization of PSD-95 is regulated by all three pathways downstream of TrkB signaling.

PubMed

Yoshii, Akira; Constantine-Paton, Martha

2014-01-01

Brain-derived neurotrophic factor (BDNF) and its receptor TrkB regulate synaptic plasticity. TrkB triggers three downstream signaling pathways; Phosphatidylinositol 3-kinase (PI3K), Phospholipase Cγ (PLCγ) and Mitogen activated protein kinases/Extracellular signal-regulated kinases (MAPK/ERK). We previously showed two distinct mechanisms whereby BDNF-TrkB pathway controls trafficking of PSD-95, which is the major scaffold at excitatory synapses and is critical for synapse maturation. BDNF activates the PI3K-Akt pathway and regulates synaptic delivery of PSD-95 via vesicular transport (Yoshii and Constantine-Paton, 2007). BDNF-TrkB signaling also triggers PSD-95 palmitoylation and its transport to synapses through the phosphorylation of the palmitoylation enzyme ZDHHC8 by a protein kinase C (PKC; Yoshii etal., 2011). The second study used PKC inhibitors chelerythrine as well as a synthetic zeta inhibitory peptide (ZIP) which was originally designed to block the brain-specific PKC isoform protein kinase Mϖ (PKMϖ). However, recent studies raise concerns about specificity of ZIP. Here, we assessed the contribution of TrkB and its three downstream pathways to the synaptic distribution of endogenous PSD-95 in cultured neurons using chemical and genetic interventions. We confirmed that TrkB, PLC, and PI3K were critical for the postsynaptic distribution of PSD-95. Furthermore, suppression of MAPK/ERK also disrupted PSD-95 expression. Next, we examined the contribution of PKC. While both chelerythrine and ZIP suppressed the postsynaptic localization of PSD-95, RNA interference for PKMϖ did not have a significant effect. This result suggests that the ZIP peptide, widely used as the "specific" PKMϖ antagonist by many investigators may block a PKC variant other than PKMϖ such as PKCλ/ι. Our results indicate that TrkB regulates postsynaptic localization of PSD-95 through all three downstream pathways, but also recommend further work to identify other PKC variants that regulate palmitoylation and synaptic localization of PSD-95.

Soluble guanylate cyclase generation of cGMP regulates migration of MGE neurons.

PubMed

Mandal, Shyamali; Stanco, Amelia; Buys, Emmanuel S; Enikolopov, Grigori; Rubenstein, John L R

2013-10-23

Here we have provided evidence that nitric oxide-cyclic GMP (NO-cGMP) signaling regulates neurite length and migration of immature neurons derived from the medial ganglionic eminence (MGE). Dlx1/2(-/-) and Lhx6(-/-) mouse mutants, which exhibit MGE interneuron migration defects, have reduced expression of the gene encoding the α subunit of a soluble guanylate cyclase (Gucy1A3). Furthermore, Dlx1/2(-/-) mouse mutants have reduced expression of NO synthase 1 (NOS1). Gucy1A3(-/-) mice have a transient reduction in cortical interneuron number. Pharmacological inhibition of soluble guanylate cyclase and NOS activity rapidly induces neurite retraction of MGE cells in vitro and in slice culture and robustly inhibits cell migration from the MGE and caudal ganglionic eminence. We provide evidence that these cellular phenotypes are mediated by activation of the Rho signaling pathway and inhibition of myosin light chain phosphatase activity.

Epigenetic Regulation by Sulforaphane: Opportunities for Breast and Prostate Cancer Chemoprevention.

PubMed

Atwell, Lauren L; Beaver, Laura M; Shannon, Jackilen; Williams, David E; Dashwood, Roderick H; Ho, Emily

2015-04-01

Sulforaphane (SFN) is a phytochemical derived from cruciferous vegetables that has multiple molecular targets and anti-cancer properties. Researchers have demonstrated several chemopreventive benefits of SFN consumption, such as reductions in tumor growth, increases in cancer cell apoptosis, and disruption of signaling within tumor microenvironments both in vitro and in vivo . Emerging evidence indicates that SFN exerts several of its chemopreventive effects by altering epigenetic mechanisms. This review summarizes evidence of the impact of SFN on epigenetic events and how they relate to the chemopreventive effects of SFN observed in preclinical and clinical studies of breast and prostate cancers. Specific areas of focus include the role of SFN in the regulation of cell cycle, apoptosis, inflammation, antioxidant defense, and cancer cell signaling and their relationships to epigenetic mechanisms. Finally, remaining challenges and research needs for translating mechanistic work with SFN into human studies and clinical intervention trials are discussed.

Jasmonate action in plant growth and development.

PubMed

Huang, Huang; Liu, Bei; Liu, Liangyu; Song, Susheng

2017-03-01

Phytohormones, including jasmonates (JAs), gibberellin, ethylene, abscisic acid, and auxin, integrate endogenous developmental cues with environmental signals to regulate plant growth, development, and defense. JAs are well- recognized lipid-derived stress hormones that regulate plant adaptations to biotic stresses, including herbivore attack and pathogen infection, as well as abiotic stresses, including wounding, ozone, and ultraviolet radiation. An increasing number of studies have shown that JAs also have functions in a remarkable number of plant developmental events, including primary root growth, reproductive development, and leaf senescence. Since the 1980s, details of the JA biosynthesis pathway, signaling pathway, and crosstalk during plant growth and development have been elucidated. Here, we summarize recent advances and give an updated overview of JA action and crosstalk in plant growth and development. © The Author 2017. Published by Oxford University Press on behalf of the Society for Experimental Biology. All rights reserved. For permissions, please email: journals.permissions@oup.com.

Docking, synthesis and pharmacological activity of novel urea-derivatives designed as p38 MAPK inhibitors.

PubMed

de Oliveira Lopes, Raquel; Romeiro, Nelilma Correia; de Lima, Cleverton Kleiton F; Louback da Silva, Leandro; de Miranda, Ana Luisa Palhares; Nascimento, Paulo Gustavo B D; Cunha, Fernando Q; Barreiro, Eliezer J; Lima, Lídia Moreira

2012-08-01

p38 mitogen-activated protein kinase (p38 MAPK) is an important signal transducing enzyme involved in many cellular regulations, including signaling pathways, pain and inflammation. Several p38 MAPK inhibitors have been developed as drug candidates to treatment of autoimmune disorders, such as rheumatoid arthritis. In this paper we reported the docking, synthesis and pharmacological activity of novel urea-derivatives (4a-e) designed as p38 MAPK inhibitors. These derivatives presented good theoretical affinity to the target p38 MAPK, standing out compound 4e (LASSBio-998), which showed a better score value compared to the prototype GK-00687. This compound was able to reduce in vitro TNF-α production and was orally active in a hypernociceptive murine model sensible to p38 MAPK inhibitors. Otherwise, compound 4e presented a dose-dependent analgesic effect in a model of antigen (mBSA)-induced arthritis and anti-inflammatory profile in carrageenan induced paw edema, indicating its potential as a new antiarthritis prototype. Copyright © 2012 Elsevier Masson SAS. All rights reserved.

Jasmonates induce both defense responses and communication in monocotyledonous and dicotyledonous plants.

PubMed

Okada, Kazunori; Abe, Hiroshi; Arimura, Gen-ichiro

2015-01-01

Jasmonic acid (JA) and its derivatives (jasmonates, JAs) are phytohormones with essential roles in plant defense against pathogenesis and herbivorous arthropods. Both the up- and down-regulation of defense responses are dependent on signaling pathways mediated by JAs as well as other stress hormones (e.g. salicylic acid), generally those involving the transcriptional and post-transcriptional regulation of transcription factors via protein modification and epigenetic regulation. In addition to the typical model plant Arabidopsis (a dicotyledon), advances in genetics research have made rice a model monocot in which innovative pest control traits can be introduced and whose JA signaling pathway can be studied. In this review, we introduce the dynamic functions of JAs in plant defense strategy using defensive substances (e.g. indole alkaloids and terpenoid phytoalexins) and airborne signals (e.g. green leaf volatiles and volatile terpenes) in response to biotrophic and necrotrophic pathogens as well as above-ground and below-ground herbivores. We then discuss the important issue of how the mutualism of herbivorous arthropods with viruses or bacteria can cause cross-talk between JA and other phytohormones to counter the defense systems. © The Author 2014. Published by Oxford University Press on behalf of Japanese Society of Plant Physiologists. All rights reserved. For permissions, please email: journals.permissions@oup.com.

A Novel AMARS Technique for Baseline Wander Removal Applied to Photoplethysmogram.

PubMed

Timimi, Ammar A K; Ali, M A Mohd; Chellappan, K

2017-06-01

A new digital filter, AMARS (aligning minima of alternating random signal) has been derived using trigonometry to regulate signal pulsations inline. The pulses are randomly presented in continuous signals comprising frequency band lower than the signal's mean rate. Frequency selective filters are conventionally employed to reject frequencies undesired by specific applications. However, these conventional filters only reduce the effects of the rejected range producing a signal superimposed by some baseline wander (BW). In this work, filters of different ranges and techniques were independently configured to preprocess a photoplethysmogram, an optical biosignal of blood volume dynamics, producing wave shapes with several BWs. The AMARS application effectively removed the encountered BWs to assemble similarly aligned trends. The removal implementation was found repeatable in both ear and finger photoplethysmograms, emphasizing the importance of BW removal in biosignal processing in retaining its structural, functional and physiological properties. We also believe that AMARS may be relevant to other biological and continuous signals modulated by similar types of baseline volatility.

An Fgf-Shh signaling hierarchy regulates early specification of the zebrafish skull.

PubMed

McCarthy, Neil; Sidik, Alfire; Bertrand, Julien Y; Eberhart, Johann K

2016-07-15

The neurocranium generates most of the craniofacial skeleton and consists of prechordal and postchordal regions. Although development of the prechordal is well studied, little is known of the postchordal region. Here we characterize a signaling hierarchy necessary for postchordal neurocranial development involving Fibroblast growth factor (Fgf) signaling for early specification of mesodermally-derived progenitor cells. The expression of hyaluron synthetase 2 (has2) in the cephalic mesoderm requires Fgf signaling and Has2 function, in turn, is required for postchordal neurocranial development. While Hedgehog (Hh)-deficient embryos also lack a postchordal neurocranium, this appears primarily due to a later defect in chondrocyte differentiation. Inhibitor studies demonstrate that postchordal neurocranial development requires early Fgf and later Hh signaling. Collectively, our results provide a mechanistic understanding of early postchordal neurocranial development and demonstrate a hierarchy of signaling between Fgf and Hh in the development of this structure. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

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

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

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

2014-11-21

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

RIP140/PGC-1α axis involved in vitamin A-induced neural differentiation by increasing mitochondrial function.

PubMed

Mu, Qing; Yu, Weidong; Zheng, Shuying; Shi, Hongxia; Li, Mei; Sun, Jie; Wang, Di; Hou, Xiaoli; Liu, Ling; Wang, Xinjuan; Zhao, Zhuran; Liang, Rong; Zhang, Xue; Dong, Wei; Zeng, Chaomei; Guo, Jingzhu

2018-03-07

Vitamin A deficiency and mitochondrial dysfunction are both associated with neural differentiation-related disorders, such as Alzheimer's disease (AD) and Down syndrome (DS). The mechanism of vitamin A-induced neural differentiation and the notion that vitamin A can regulate the morphology and function of mitochondria in its induction of neural differentiation through the RIP140/PGC-1α axis are unclear. The aim of this study was to investigate the roles and underlying mechanisms of RIP140/PGC-1α axis in vitamin A-induced neural differentiation. Human neuroblastoma cells (SH-SY5Y) were used as a model of neural stem cells, which were incubated with DMSO, 9-cis-retinoic acid (9-cis-RA), 13-cis-retinoic acid (13-cis-RA) and all-trans-retinoic acid (at-RA). Neural differentiation of SH-SY5Y was evaluated by Sandquist calculation, combined with immunofluorescence and real-time polymerase chain reaction (PCR) of neural markers. Mitochondrial function was estimated by ultrastructure assay using transmission electron microscopy (TEM) combined with the expression of PGC-1α and NEMGs using real-time PCR. The participation of the RA signaling pathway was demonstrated by adding RA receptor antagonists. Vitamin A derivatives are able to regulate mitochondrial morphology and function, and furthermore to induce neural differentiation through the RA signaling pathway. The RIP140/PGC-1α axis is involved in the regulation of mitochondrial function in vitamin A derivative-induced neural differentiation.

Regulation of skeletal muscle blood flow during exercise in ageing humans

PubMed Central

Hearon, Christopher M.

2015-01-01

Abstract The regulation of skeletal muscle blood flow and oxygen delivery to contracting skeletal muscle is complex and involves the mechanical effects of muscle contraction; local metabolic, red blood cell and endothelium‐derived substances; and the sympathetic nervous system (SNS). With advancing age in humans, skeletal muscle blood flow is typically reduced during dynamic exercise and this is due to a lower vascular conductance, which could ultimately contribute to age‐associated reductions in aerobic exercise capacity, a primary predictor of mortality in both healthy and diseased ageing populations. Recent findings have highlighted the contribution of endothelium‐derived substances to blood flow control in contracting muscle of older adults. With advancing age, impaired nitric oxide availability due to scavenging by reactive oxygen species, in conjunction with elevated vasoconstrictor signalling via endothelin‐1, reduces the local vasodilatory response to muscle contraction. Additionally, ageing impairs the ability of contracting skeletal muscle to blunt sympathetic vasoconstriction (i.e. ‘functional sympatholysis’), which is critical for the proper regulation of tissue blood flow distribution and oxygen delivery, and could further reduce skeletal muscle perfusion during high intensity and/or large muscle mass exercise in older adults. We propose that initiation of endothelium‐dependent hyperpolarization is the underlying signalling event necessary to properly modulate sympathetic vasoconstriction in contracting muscle, and that age‐associated impairments in red blood cell adenosine triphosphate release and stimulation of endothelium‐dependent vasodilatation may explain impairments in both local vasodilatation and functional sympatholysis with advancing age in humans. PMID:26332887

Natural product-derived pharmacological modulators of Nrf2/ARE pathway for chronic diseases.

PubMed

Kumar, Hemant; Kim, In-Su; More, Sandeep Vasant; Kim, Byung-Wook; Choi, Dong-Kug

2014-01-01

Covering: 2000 to 2013. Oxidative stress is the central component of chronic diseases. The nuclear factor erythroid 2-related factor 2/antioxidant response element (Nrf2/ARE) pathway is vital in the up-regulation of cytoprotective genes and enzymes in response to oxidative stress and treatment with certain dietary phytochemicals. Herein, we classify bioactive compounds derived from natural products that are Nrf2/ARE pathway activators and recapitulate the molecular mechanisms for inducing Nrf2 to provide favorable effects in experimental models of chronic diseases. Moreover, pharmacological inhibition of Nrf2 signalling has emerged as promising strategy against multi-drug resistance thereby improving the treatment efficacy. We have also enlisted natural product-derived inhibitors of Nrf2/ARE pathway.

NF-κB RelB Negatively Regulates Osteoblast Differentiation and Bone Formation

PubMed Central

Yao, Zhenqiang; Li, Yanyun; Yin, Xiaoxiang; Dong, Yufeng; Xing, Lianping; Boyce, Brendan F.

2013-01-01

RelA-mediated NF-κB canonical signaling promotes mesenchymal progenitor cell (MPC) proliferation, but inhibits differentiation of mature osteoblasts (OBs) and thus negatively regulates bone formation. Previous studies suggest that NF-κB RelB may also negatively regulate bone formation through non-canonical signaling, but they involved a complex knockout mouse model and the molecular mechanisms involved were not investigated. Here, we report that RelB−/− mice develop age-related increased trabecular bone mass associated with increased bone formation. RelB−/− bone marrow stromal cells expanded faster in vitro and have enhanced OB differentiation associated with increased expression of the osteoblastogenic transcription factor, Runx2. In addition, RelB directly targeted the Runx2 promoter to inhibit its activation. Importantly, RelB−/− bone-derived MPCs formed bone more rapidly than wild-type cells after they were injected into a murine tibial bone defect model. Our findings indicate that RelB negatively regulates bone mass as mice age and limits bone formation in healing bone defects, suggesting that inhibition of RelB could reduce age-related bone loss and enhance bone repair. PMID:24115294

Central nervous system regulation of intestinal lipid and lipoprotein metabolism.

PubMed

Farr, Sarah; Taher, Jennifer; Adeli, Khosrow

2016-02-01

In response to nutrient availability, the small intestine and brain closely communicate to modulate energy homeostasis and metabolism. The gut-brain axis involves complex nutrient sensing mechanisms and an integration of neuronal and hormonal signaling. This review summarizes recent evidence implicating the gut-brain axis in regulating lipoprotein metabolism, with potential implications for the dyslipidemia of insulin resistant states. The intestine and brain possess distinct mechanisms for sensing lipid availability, which triggers subsequent regulation of feeding, glucose homeostasis, and adipose tissue metabolism. More recently, central receptors, neuropeptides, and gut hormones that communicate with the brain have been shown to modulate hepatic and intestinal lipoprotein metabolism via parasympathetic and sympathetic signaling. Gut-derived glucagon-like peptides appear to be particularly important in modulating the intestinal secretion of chylomicron particles via a novel brain-gut axis. Dysregulation of these pathways may contribute to postprandial diabetic dyslipidemia. Emerging evidence implicates the central and enteric nervous systems in controlling many aspects of lipid and lipoprotein metabolism. Bidirectional communication between the gut and brain involving neuronal pathways and gut peptides is critical for regulating feeding and metabolism, and forms a neuroendocrine circuit to modulate dietary fat absorption and intestinal production of atherogenic chylomicron particles.

Mice lacking MKP-1 and MKP-5 Reveal Hierarchical Regulation of Regenerative Myogenesis.

PubMed

Shi, Hao; Gatzke, Florian; Molle, Julia M; Lee, Han Bin; Helm, Emma T; Oldham, Jessie J; Zhang, Lei; Gerrard, David E; Bennett, Anton M

2015-11-12

The relative contribution of the MAP kinase phosphatases (MKPs) in the integration of MAP kinase-dependent signaling during regenerative myogenesis has yet to be fully investigated. MKP-1 and MKP-5 maintain skeletal muscle homeostasis by providing positive and negative effects on regenerative myogenesis, respectively. In order to define the hierarchical contributions of MKP-1 and MKP-5 in the regulation of regenerative myogenesis we genetically ablated both MKPs in mice. MKP-1/MKP 5-deficient double-knockout (MKP1/5- DKO) mice were viable, and upon skeletal muscle injury, were severely impaired in their capacity to regenerate skeletal muscle. Satellite cells were fewer in number in MKP1/5-DKO mice and displayed a reduced proliferative capacity as compared with those derived from wild-type mice. MKP1/5-DKO mice exhibited increased inflammation and the macrophage M1 to M2 transition during the resolution of inflammation was impaired following injury. These results demonstrate that the actions of MKP-1 to positively regulate myogenesis predominate over those of MKP-5, which negatively regulates myogenesis. Hence, MKP-1 and MKP-5 function to maintain skeletal muscle homeostasis through non-overlapping and opposing signaling pathways.

Mice lacking MKP-1 and MKP-5 Reveal Hierarchical Regulation of Regenerative Myogenesis

PubMed Central

Shi, Hao; Gatzke, Florian; Molle, Julia M.; Lee, Han Bin; Helm, Emma T.; Oldham, Jessie J.; Zhang, Lei; Gerrard, David E.; Bennett, Anton M.

2015-01-01

The relative contribution of the MAP kinase phosphatases (MKPs) in the integration of MAP kinase-dependent signaling during regenerative myogenesis has yet to be fully investigated. MKP-1 and MKP-5 maintain skeletal muscle homeostasis by providing positive and negative effects on regenerative myogenesis, respectively. In order to define the hierarchical contributions of MKP-1 and MKP-5 in the regulation of regenerative myogenesis we genetically ablated both MKPs in mice. MKP-1/MKP 5-deficient double-knockout (MKP1/5- DKO) mice were viable, and upon skeletal muscle injury, were severely impaired in their capacity to regenerate skeletal muscle. Satellite cells were fewer in number in MKP1/5-DKO mice and displayed a reduced proliferative capacity as compared with those derived from wild-type mice. MKP1/5-DKO mice exhibited increased inflammation and the macrophage M1 to M2 transition during the resolution of inflammation was impaired following injury. These results demonstrate that the actions of MKP-1 to positively regulate myogenesis predominate over those of MKP-5, which negatively regulates myogenesis. Hence, MKP-1 and MKP-5 function to maintain skeletal muscle homeostasis through non-overlapping and opposing signaling pathways. PMID:27064463

Hedgehog signaling is synergistically enhanced by nutritional deprivation and ligand stimulation in human fibroblasts of Gorlin syndrome.

PubMed

Mizuochi, Hiromi; Fujii, Katsunori; Shiohama, Tadashi; Uchikawa, Hideki; Shimojo, Naoki

2015-02-13

Hedgehog signaling is a pivotal developmental pathway that comprises hedgehog, PTCH1, SMO, and GLI proteins. Mutations in PTCH1 are responsible for Gorlin syndrome, which is characterized by developmental defects and tumorigenicity. Although the hedgehog pathway has been investigated extensively in Drosophila and mice, its functional roles have not yet been determined in human cells. In order to elucidate the mechanism by which transduction of the hedgehog signal is regulated in human tissues, we employed human fibroblasts derived from three Gorlin syndrome patients and normal controls. We investigated GLI1 transcription, downstream of hedgehog signaling, to assess native signal transduction, and then treated fibroblasts with a recombinant human hedgehog protein with or without serum deprivation. We also examined the transcriptional levels of hedgehog-related genes under these conditions. The expression of GLI1 mRNA was significantly higher in Gorlin syndrome-derived fibroblasts than in control cells. Hedgehog stimulation and nutritional deprivation synergistically enhanced GLI1 transcription levels, and this was blocked more efficiently by vismodegib, a SMO inhibitor, than by the natural compound, cyclopamine. Messenger RNA profiling revealed the increased expression of Wnt signaling and morphogenetic molecules in these fibroblasts. These results indicated that the hedgehog stimulation and nutritional deprivation synergistically activated the hedgehog signaling pathway in Gorlin syndrome fibroblasts, and this was associated with increments in the transcription levels of hedgehog-related genes such as those involved in Wnt signaling. These fibroblasts may become a significant tool for predicting the efficacies of hedgehog molecular-targeted therapies such as vismodegib. Copyright © 2015 Elsevier Inc. All rights reserved.

A novel insulinotropic mechanism of whole grain-derived γ-oryzanol via the suppression of local dopamine D2 receptor signalling in mouse islet.

PubMed

Kozuka, Chisayo; Sunagawa, Sumito; Ueda, Rei; Higa, Moritake; Ohshiro, Yuzuru; Tanaka, Hideaki; Shimizu-Okabe, Chigusa; Takayama, Chitoshi; Matsushita, Masayuki; Tsutsui, Masato; Ishiuchi, Shogo; Nakata, Masanori; Yada, Toshihiko; Miyazaki, Jun-Ichi; Oyadomari, Seiichi; Shimabukuro, Michio; Masuzaki, Hiroaki

2015-07-03

γ-Oryzanol, derived from unrefined rice, attenuated the preference for dietary fat in mice, by decreasing hypothalamic endoplasmic reticulum stress. However, no peripheral mechanisms, whereby γ-oryzanol could ameliorate glucose dyshomeostasis were explored. Dopamine D 2 receptor signalling locally attenuates insulin secretion in pancreatic islets, presumably via decreased levels of intracellular cAMP. We therefore hypothesized that γ-oryzanol would improve high-fat diet (HFD)-induced dysfunction of islets through the suppression of local D 2 receptor signalling. Glucose metabolism and regulation of molecules involved in D 2 receptor signalling in pancreatic islets were investigated in male C57BL/6J mice, fed HFD and treated with γ-oryzanol . In isolated murine islets and the beta cell line, MIN6 , the effects of γ-oryzanol on glucose-stimulated insulin secretion (GSIS) was analysed using siRNA for D 2 receptors and a variety of compounds which alter D 2 receptor signalling. In islets, γ-oryzanol enhanced GSIS via the activation of the cAMP/PKA pathway. Expression of molecules involved in D 2 receptor signalling was increased in islets from HFD-fed mice, which were reciprocally decreased by γ-oryzanol. Experiments with siRNA for D 2 receptors and D 2 receptor ligands in vitro suggest that γ-oryzanol suppressed D 2 receptor signalling and augmented GSIS. γ-Oryzanol exhibited unique anti-diabetic properties. The unexpected effects of γ-oryzanol on D 2 receptor signalling in islets may provide a novel; natural food-based, approach to anti-diabetic therapy. © 2015 The British Pharmacological Society.

Bicaudal-D1 regulates the intracellular sorting and signalling of neurotrophin receptors

PubMed Central

Terenzio, Marco; Golding, Matthew; Russell, Matthew R G; Wicher, Krzysztof B; Rosewell, Ian; Spencer-Dene, Bradley; Ish-Horowicz, David; Schiavo, Giampietro

2014-01-01

We have identified a new function for the dynein adaptor Bicaudal D homolog 1 (BICD1) by screening a siRNA library for genes affecting the dynamics of neurotrophin receptor-containing endosomes in motor neurons (MNs). Depleting BICD1 increased the intracellular accumulation of brain-derived neurotrophic factor (BDNF)-activated TrkB and p75 neurotrophin receptor (p75NTR) by disrupting the endosomal sorting, reducing lysosomal degradation and increasing the co-localisation of these neurotrophin receptors with retromer-associated sorting nexin 1. The resulting re-routing of active receptors increased their recycling to the plasma membrane and altered the repertoire of signalling-competent TrkB isoforms and p75NTR available for ligand binding on the neuronal surface. This resulted in attenuated, but more sustained, AKT activation in response to BDNF stimulation. These data, together with our observation that Bicd1 expression is restricted to the developing nervous system when neurotrophin receptor expression peaks, indicate that BICD1 regulates neurotrophin signalling by modulating the endosomal sorting of internalised ligand-activated receptors. PMID:24920579

Bicaudal-D1 regulates the intracellular sorting and signalling of neurotrophin receptors.

PubMed

Terenzio, Marco; Golding, Matthew; Russell, Matthew R G; Wicher, Krzysztof B; Rosewell, Ian; Spencer-Dene, Bradley; Ish-Horowicz, David; Schiavo, Giampietro

2014-07-17

We have identified a new function for the dynein adaptor Bicaudal D homolog 1 (BICD1) by screening a siRNA library for genes affecting the dynamics of neurotrophin receptor-containing endosomes in motor neurons (MNs). Depleting BICD1 increased the intracellular accumulation of brain-derived neurotrophic factor (BDNF)-activated TrkB and p75 neurotrophin receptor (p75(NTR)) by disrupting the endosomal sorting, reducing lysosomal degradation and increasing the co-localisation of these neurotrophin receptors with retromer-associated sorting nexin 1. The resulting re-routing of active receptors increased their recycling to the plasma membrane and altered the repertoire of signalling-competent TrkB isoforms and p75(NTR) available for ligand binding on the neuronal surface. This resulted in attenuated, but more sustained, AKT activation in response to BDNF stimulation. These data, together with our observation that Bicd1 expression is restricted to the developing nervous system when neurotrophin receptor expression peaks, indicate that BICD1 regulates neurotrophin signalling by modulating the endosomal sorting of internalised ligand-activated receptors. © 2014 The Authors.

Zebrafish (Danio rerio) androgen receptor: sequence homology and up-regulation by the fungicide vinclozolin.

PubMed

Smolinsky, Amanda N; Doughman, Jennifer M; Kratzke, Liên-Thành C; Lassiter, Christopher S

2010-03-01

Steroid hormones regulate gene expression in organisms by binding to receptor proteins. These hormones include the androgens, which signal through androgen receptors (ARs). Endocrine disrupters (EDCs) are chemicals in the environment that adversely affect organisms by binding to nuclear receptors, including ARs. Vinclozolin, a fungicide used on fruit and vegetable crops, is a known anti-androgen, a type of EDC that blocks signals from testosterone and its derivatives. In order to better understand the effects of EDCs, further research on androgen receptors and other hormone signaling pathways is necessary. In this study, we demonstrate the evolutionary conservation between the genomic structure of the human and zebrafish ar genes and find that ar mRNA expression increases in zebrafish embryos exposed to vinclozolin, which may be evolutionarily conserved as well. At 48 and 72 h post-fertilization, vinclozolin-treated embryos express ar mRNA 8-fold higher than the control level. These findings suggest that zebrafish embryos attempt to compensate for the presence of an anti-androgen by increasing the number of androgen receptors available.

Sigma-1 receptor chaperone at the ER-mitochondrion interface mediates the mitochondrion-ER-nucleus signaling for cellular survival.

PubMed

Mori, Tomohisa; Hayashi, Teruo; Hayashi, Eri; Su, Tsung-Ping

2013-01-01

The membrane of the endoplasmic reticulum (ER) of a cell forms contacts directly with mitochondria whereby the contact is referred to as the mitochondrion-associated ER membrane or the MAM. Here we found that the MAM regulates cellular survival via an MAM-residing ER chaperone the sigma-1 receptor (Sig-1R) in that the Sig-1R chaperones the ER stress sensor IRE1 to facilitate inter-organelle signaling for survival. IRE1 is found in this study to be enriched at the MAM in CHO cells. We found that IRE1 is stabilized at the MAM by Sig-1Rs when cells are under ER stress. Sig-1Rs stabilize IRE1 and thus allow for conformationally correct IRE1 to dimerize into the long-lasting, activated endonuclease. The IRE1 at the MAM also responds to reactive oxygen species derived from mitochondria. Therefore, the ER-mitochondrion interface serves as an important subcellular entity in the regulation of cellular survival by enhancing the stress-responding signaling between mitochondria, ER, and nucleus.

Bi-directional gap junction-mediated soma-germline communication is essential for spermatogenesis.

PubMed

Smendziuk, Christopher M; Messenberg, Anat; Vogl, A Wayne; Tanentzapf, Guy

2015-08-01

Soma-germline interactions play conserved essential roles in regulating cell proliferation, differentiation, patterning and homeostasis in the gonad. In the Drosophila testis, secreted signalling molecules of the JAK-STAT, Hedgehog, BMP and EGF pathways are used to mediate soma-germline communication. Here, we demonstrate that gap junctions may also mediate direct, bi-directional signalling between the soma and germ line. When gap junctions between the soma and germ line are disrupted, germline differentiation is blocked and germline stem cells are not maintained. In the soma, gap junctions are required to regulate proliferation and differentiation. Localization and RNAi-mediated knockdown studies reveal that gap junctions in the fly testis are heterotypic channels containing Zpg (Inx4) and Inx2 on the germ line and the soma side, respectively. Overall, our results show that bi-directional gap junction-mediated signalling is essential to coordinate the soma and germ line to ensure proper spermatogenesis in Drosophila. Moreover, we show that stem cell maintenance and differentiation in the testis are directed by gap junction-derived cues. © 2015. Published by The Company of Biologists Ltd.

Sigma-1 Receptor Chaperone at the ER-Mitochondrion Interface Mediates the Mitochondrion-ER-Nucleus Signaling for Cellular Survival

PubMed Central

Mori, Tomohisa; Hayashi, Teruo; Hayashi, Eri; Su, Tsung-Ping

2013-01-01

The membrane of the endoplasmic reticulum (ER) of a cell forms contacts directly with mitochondria whereby the contact is referred to as the mitochondrion-associated ER membrane or the MAM. Here we found that the MAM regulates cellular survival via an MAM-residing ER chaperone the sigma-1 receptor (Sig-1R) in that the Sig-1R chaperones the ER stress sensor IRE1 to facilitate inter-organelle signaling for survival. IRE1 is found in this study to be enriched at the MAM in CHO cells. We found that IRE1 is stabilized at the MAM by Sig-1Rs when cells are under ER stress. Sig-1Rs stabilize IRE1 and thus allow for conformationally correct IRE1 to dimerize into the long-lasting, activated endonuclease. The IRE1 at the MAM also responds to reactive oxygen species derived from mitochondria. Therefore, the ER-mitochondrion interface serves as an important subcellular entity in the regulation of cellular survival by enhancing the stress-responding signaling between mitochondria, ER, and nucleus. PMID:24204710

Ties that bind: the integration of plastid signalling pathways in plant cell metabolism.

PubMed

Brunkard, Jacob O; Burch-Smith, Tessa M

2018-04-13

Plastids are critical organelles in plant cells that perform diverse functions and are central to many metabolic pathways. Beyond their major roles in primary metabolism, of which their role in photosynthesis is perhaps best known, plastids contribute to the biosynthesis of phytohormones and other secondary metabolites, store critical biomolecules, and sense a range of environmental stresses. Accordingly, plastid-derived signals coordinate a host of physiological and developmental processes, often by emitting signalling molecules that regulate the expression of nuclear genes. Several excellent recent reviews have provided broad perspectives on plastid signalling pathways. In this review, we will highlight recent advances in our understanding of chloroplast signalling pathways. Our discussion focuses on new discoveries illuminating how chloroplasts determine life and death decisions in cells and on studies elucidating tetrapyrrole biosynthesis signal transduction networks. We will also examine the role of a plastid RNA helicase, ISE2, in chloroplast signalling, and scrutinize intriguing results investigating the potential role of stromules in conducting signals from the chloroplast to other cellular locations. © 2018 The Author(s). Published by Portland Press Limited on behalf of the Biochemical Society.

Structure and mechanism of the essential two-component signal-transduction system WalKR in Staphylococcus aureus

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

Ji, Quanjiang; Chen, Peter J.; Qin, Guangrong

Most low GC Gram-positive bacteria possess an essential walKR two-component system (TCS) for signal transduction involved in regulating cell wall homoeostasis. Despite the well-established intracellular regulatory mechanism, the role of this TCS in extracellular signal recognition and factors that modulate the activity of this TCS remain largely unknown. Here we identify the extracellular receptor of the kinase ‘WalK’ (erWalK) as a key hub for bridging extracellular signal input and intracellular kinase activity modulation in Staphylococcus aureus. Characterization of the crystal structure of erWalK revealed a canonical Per-Arnt-Sim (PAS) domain for signal sensing. Single amino-acid mutation of potential signal-transduction residues resultedmore » in severely impaired function of WalKR. A small molecule derived from structure-based virtual screening against erWalK is capable of selectively activating the walKR TCS. Lastly, the molecular level characterization of erWalK will not only facilitate exploration of natural signal(s) but also provide a template for rational design of erWalK inhibitors.« less

Structure and mechanism of the essential two-component signal-transduction system WalKR in Staphylococcus aureus

DOE PAGES

Ji, Quanjiang; Chen, Peter J.; Qin, Guangrong; ...

2016-03-18

Most low GC Gram-positive bacteria possess an essential walKR two-component system (TCS) for signal transduction involved in regulating cell wall homoeostasis. Despite the well-established intracellular regulatory mechanism, the role of this TCS in extracellular signal recognition and factors that modulate the activity of this TCS remain largely unknown. Here we identify the extracellular receptor of the kinase ‘WalK’ (erWalK) as a key hub for bridging extracellular signal input and intracellular kinase activity modulation in Staphylococcus aureus. Characterization of the crystal structure of erWalK revealed a canonical Per-Arnt-Sim (PAS) domain for signal sensing. Single amino-acid mutation of potential signal-transduction residues resultedmore » in severely impaired function of WalKR. A small molecule derived from structure-based virtual screening against erWalK is capable of selectively activating the walKR TCS. Lastly, the molecular level characterization of erWalK will not only facilitate exploration of natural signal(s) but also provide a template for rational design of erWalK inhibitors.« less

Live imaging and genetic analysis of mouse notochord formation reveals regional morphogenetic mechanisms.

PubMed

Yamanaka, Yojiro; Tamplin, Owen J; Beckers, Anja; Gossler, Achim; Rossant, Janet

2007-12-01

The node and notochord have been extensively studied as signaling centers in the vertebrate embryo. The morphogenesis of these tissues, particularly in mouse, is not well understood. Using time-lapse live imaging and cell lineage tracking, we show the notochord has distinct morphogenetic origins along the anterior-posterior axis. The anterior head process notochord arises independently of the node by condensation of dispersed cells. The trunk notochord is derived from the node and forms by convergent extension. The tail notochord forms by node-derived progenitors that actively migrate toward the posterior. We also reveal distinct genetic regulation within these different regions. We show that Foxa2 compensates for and genetically interacts with Noto in the trunk notochord, and that Noto has an evolutionarily conserved role in regulating axial versus paraxial cell fate. Therefore, we propose three distinct regions within the mouse notochord, each with unique morphogenetic origins.

SIRT1 and HIF1α signaling in metabolism and immune responses.

PubMed

Yu, Qing; Dong, Lin; Li, Yan; Liu, Gaungwei

2018-04-01

SIRT1 and HIF1α are regarded as two key metabolic sensors in cellular metabolism pathways and play vital roles in influencing immune responses. SIRT1 and HIF1α regulate immune responses in metabolism-dependent and -independent ways. Here, we summarized the recent knowledge of SIRT1 and HIF1α signaling in metabolism and immune responses. HIF1α is a direct target of SIRT1. Sometimes, SIRT1 and HIF1α cooperate or act separately to mediate immune responses. In innate immune responses, SIRT1 can regulate the glycolytic activity of myeloid-derived suppressor cells (MDSCs) and influence MDSC functional differentiation. SIRT1 can regulate monocyte function through NF-κB and PGC-1, accompanying an increased NAD + level. The SIRT1-HIF1α axis bridges the innate immune signal to an adaptive immune response by directing cytokine production of dendritic cells in a metabolism-independent manner, promoting the differentiation of CD4 + T cells. For adaptive immune cells, SIRT1 can mediate the differentiation of inflammatory T cell subsets in a NAD + -dependent manner. HIF1α can stimulate some glycolysis-associated genes and regulate the ATP and ROS generations. In addition, SIRT1-and HIF1α-associated metabolism inhibits the activity of mTOR, thus negatively regulating the differentiation and function of Th9 cells. As immune cells are crucial in controlling immune-associated diseases, SIRT1-and HIF1α associated-metabolism is closely linked to immune-associated diseases, including infection, tumors, allergic airway inflammation, and autoimmune diseases. Copyright © 2018 Elsevier B.V. All rights reserved.

BMP signaling in the human fetal ovary is developmentally regulated and promotes primordial germ cell apoptosis.

PubMed

Childs, Andrew J; Kinnell, Hazel L; Collins, Craig S; Hogg, Kirsten; Bayne, Rosemary A L; Green, Samira J; McNeilly, Alan S; Anderson, Richard A

2010-08-01

Primordial germ cells (PGCs) are the embryonic precursors of gametes in the adult organism, and their development, differentiation, and survival are regulated by a combination of growth factors collectively known as the germ cell niche. Although many candidate niche components have been identified through studies on mouse PGCs, the growth factor composition of the human PGC niche has not been studied extensively. Here we report a detailed analysis of the expression of components of the bone morphogenetic protein (BMP) signaling apparatus in the human fetal ovary, from postmigratory PGC proliferation to the onset of primordial follicle formation. We find developmentally regulated and reciprocal patterns of expression of BMP2 and BMP4 and identify germ cells to be the exclusive targets of ovarian BMP signaling. By establishing long-term cultures of human fetal ovaries in which PGCs are retained within their physiological niche, we find that BMP4 negatively regulates postmigratory PGC numbers in the human fetal ovary by promoting PGC apoptosis. Finally, we report expression of both muscle segment homeobox (MSX)1 and MSX2 in the human fetal ovary and reveal a selective upregulation of MSX2 expression in human fetal ovary in response to BMP4, suggesting this gene may act as a downstream effector of BMP-induced apoptosis in the ovary, as in other systems. These data reveal for the first time growth factor regulation of human PGC development in a physiologically relevant context and have significant implications for the development of cultures systems for the in vitro maturation of germ cells, and their derivation from pluripotent stem cells.

Light-Regulated Electrochemical Sensor Array for Efficiently Discriminating Hazardous Gases.

PubMed

Liang, Hongqiu; Zhang, Xin; Sun, Huihui; Jin, Han; Zhang, Xiaowei; Jin, Qinghui; Zou, Jie; Haick, Hossam; Jian, Jiawen

2017-10-27

Inadequate detection limit and unsatisfactory discrimination features remain the challenging issues for the widely applied electrochemical gas sensors. Quite recently, we confirmed that light-regulated electrochemical reaction significantly enhanced the electrocatalytic activity, and thereby can potentially extend the detection limit to the parts per billion (ppb) level. Nevertheless, impact of the light-regulated electrochemical reaction on response selectivity has been discussed less. Herein, we systematically report on the effect of illumination on discrimination features via design and fabrication of a light-regulated electrochemical sensor array. Upon illumination (light on), response signal to the examined gases (C 3 H 6 , NO, and CO) is selectively enhanced, resulting in the sensor array demonstrating disparate response patterns when compared with that of the sensor array operated at light off. Through processing all the response patterns derived from both light on and light off with a pattern recognition algorithm, a satisfactory discrimination feature is observed. In contrast, apparent mutual interference between NO and CO is found when the sensor array is solely operated without illumination. The impact mechanism of the illumination is studied and it is deduced that the effect of the illumination on the discriminating features can be mainly attributed to the competition of electrocatalytic activity and gas-phase reactivity. If the enhanced electrocatalytic activity (to specific gas) dominates the whole sensing progress, enhancements in the corresponding response signal would be observed upon illumination. Otherwise, illumination gives a negligible impact. Hence, the response signal to part of the examined gases is selectively enhanced by illumination. Conclusively, light-regulated electrochemical reaction would provide an efficient approach to designing future smart sensing devices.

LRP1 regulates architecture of the vascular wall by controlling PDGFRbeta-dependent phosphatidylinositol 3-kinase activation.

PubMed

Zhou, Li; Takayama, Yoshiharu; Boucher, Philippe; Tallquist, Michelle D; Herz, Joachim

2009-09-09

Low density lipoprotein receptor-related protein 1 (LRP1) protects against atherosclerosis by regulating the activation of platelet-derived growth factor receptor beta (PDGFRbeta) in vascular smooth muscle cells (SMCs). Activated PDGFRbeta undergoes tyrosine phosphorylation and subsequently interacts with various signaling molecules, including phosphatidylinositol 3-kinase (PI3K), which binds to the phosphorylated tyrosine 739/750 residues in mice, and thus regulates actin polymerization and cell movement. In this study, we found disorganized actin in the form of membrane ruffling and enhanced cell migration in LRP1-deficient (LRP1-/-) SMCs. Marfan syndrome-like phenotypes such as tortuous aortas, disrupted elastic layers and abnormally activated transforming growth factor beta (TGFbeta) signaling are present in smooth muscle-specific LRP1 knockout (smLRP1-/-) mice. To investigate the role of LRP1-regulated PI3K activation by PDGFRbeta in atherogenesis, we generated a strain of smLRP1-/- mice in which tyrosine 739/750 of the PDGFRbeta had been mutated to phenylalanines (PDGFRbeta F2/F2). Spontaneous atherosclerosis was significantly reduced in the absence of hypercholesterolemia in these mice compared to smLRP1-/- animals that express wild type PDGFR. Normal actin organization was restored and spontaneous SMC migration as well as PDGF-BB-induced chemotaxis was dramatically reduced, despite continued overactivation of TGFbeta signaling, as indicated by high levels of nuclear phospho-Smad2. Our data suggest that LRP1 regulates actin organization and cell migration by controlling PDGFRbeta-dependent activation of PI3K. TGFbeta activation alone is not sufficient for the expression of the Marfan-like vascular phenotype. Thus, regulation of PI3 Kinase by PDGFRbeta is essential for maintaining vascular integrity, and for the prevention of atherosclerosis as well as Marfan syndrome.

Regulation of dendritic cell function by insulin/IGF-1/PI3K/Akt signaling through klotho expression.

PubMed

Xuan, Nguyen Thi; Hoang, Nguyen Huy; Nhung, Vu Phuong; Duong, Nguyen Thuy; Ha, Nguyen Hai; Hai, Nong Van

2017-06-01

Insulin or insulin-like growth factor 1 (IGF-1) promotes the activation of phosphoinositide 3 kinase (PI3K)/Akt signaling in immune cells including dendritic cells (DCs), the most potent professional antigen-presenting cells for naive T cells. Klotho, an anti-aging protein, participates in the regulation of the PI3K/Akt signaling, thus the Ca 2+ -dependent migration is reduced in klotho-deficient DCs. The present study explored the effects of insulin/IGF-1 on DC function through klotho expression. To this end, the mouse bone marrow cells were isolated and cultured with GM-CSF to attain bone marrow-derived DCs (BMDCs). Cells were treated with insulin or IGF-1 and followed by stimulating with lipopolysaccharides (LPS). Tumor necrosis factor (TNF)-α formation was examined by enzyme-linked immunosorbent assay (ELISA). Phagocytosis was analyzed by FITC-dextran uptake assay. The expression of klotho was determined by quantitative PCR, immunoprecipitation and western blotting. As a result, treatment of the cells with insulin/IGF-1 resulted in reducing the klotho expression as well as LPS-stimulated TNF-α release and increasing the FITC-dextran uptake but unaltering reactive oxygen species (ROS) production in BMDCs. The effects were abolished by using pharmacological inhibition of PI3K/Akt with LY294002 and paralleled by transfecting DCs with klotho siRNA. In conclusion, the regulation of klotho sensitive DC function by IGF-1 or insulin is mediated through PI3K/Akt signaling pathway in BMDCs.

Plakophilin-1, a Novel Wnt Signaling Regulator, Is Critical for Tooth Development and Ameloblast Differentiation

PubMed Central

Arai, Chieko; Yamada, Aya; Saito, Kan; Ishikawa, Masaki; Xue, Han; Funada, Keita; Haruyama, Naoto; Yamada, Yoshihiko; Fukumoto, Satoshi; Takahashi, Ichiro

2016-01-01

Tooth morphogenesis is initiated by reciprocal interactions between the ectoderm and neural crest-derived mesenchyme, and the Wnt signaling pathway is involved in this process. We found that Plakophilin (PKP)1, which is associated with diseases such as ectodermal dysplasia/skin fragility syndrome, was highly expressed in teeth and skin, and was upregulated during tooth development. We hypothesized that PKP1 regulates Wnt signaling via its armadillo repeat domain in a manner similar to β-catenin. To determine its role in tooth development, we performed Pkp1 knockdown experiments using ex vivo organ cultures and cell cultures. Loss of Pkp1 reduced the size of tooth germs and inhibited dental epithelial cell proliferation, which was stimulated by Wnt3a. Furthermore, transfected PKP1-emerald green fluorescent protein was translocated from the plasma membrane to the nucleus upon stimulation with Wnt3a and LiCl, which required the PKP1 N terminus (amino acids 161 to 270). Localization of PKP1, which is known as an adhesion-related desmosome component, shifted to the plasma membrane during ameloblast differentiation. In addition, Pkp1 knockdown disrupted the localization of Zona occludens 1 in tight junctions and inhibited ameloblast differentiation; the two proteins were shown to directly interact by immunoprecipitation. These results implicate the participation of PKP1 in early tooth morphogenesis as an effector of canonical Wnt signaling that controls ameloblast differentiation via regulation of the cell adhesion complex. PMID:27015268

High fructose-mediated attenuation of insulin receptor signaling does not affect PDGF-induced proliferative signaling in vascular smooth muscle cells.

PubMed

Osman, Islam; Poulose, Ninu; Ganapathy, Vadivel; Segar, Lakshman

2016-11-15

Insulin resistance is associated with accelerated atherosclerosis. Although high fructose is known to induce insulin resistance, it remains unclear as to how fructose regulates insulin receptor signaling and proliferative phenotype in vascular smooth muscle cells (VSMCs), which play a major role in atherosclerosis. Using human aortic VSMCs, we investigated the effects of high fructose treatment on insulin receptor substrate-1 (IRS-1) serine phosphorylation, insulin versus platelet-derived growth factor (PDGF)-induced phosphorylation of Akt, S6 ribosomal protein, and extracellular signal-regulated kinase (ERK), and cell cycle proteins. In comparison with PDGF (a potent mitogen), neither fructose nor insulin enhanced VSMC proliferation and cyclin D1 expression. d-[ 14 C(U)]fructose uptake studies revealed a progressive increase in fructose uptake in a time-dependent manner. Concentration-dependent studies with high fructose (5-25mM) showed marked increases in IRS-1 serine phosphorylation, a key adapter protein in insulin receptor signaling. Accordingly, high fructose treatment led to significant diminutions in insulin-induced phosphorylation of downstream signaling components including Akt and S6. In addition, high fructose significantly diminished insulin-induced ERK phosphorylation. Nevertheless, high fructose did not affect PDGF-induced key proliferative signaling events including phosphorylation of Akt, S6, and ERK and expression of cyclin D1 protein. Together, high fructose dysregulates IRS-1 phosphorylation state and proximal insulin receptor signaling in VSMCs, but does not affect PDGF-induced proliferative signaling. These findings suggest that systemic insulin resistance rather than VSMC-specific dysregulation of insulin receptor signaling by high fructose may play a major role in enhancing atherosclerosis and neointimal hyperplasia. Copyright © 2016 Elsevier B.V. All rights reserved.

Effects of Chinese medicinal herbs on expression of brain-derived Neurotrophic factor (BDNF) and its interaction with human breast cancer MDA-MB-231 cells and endothelial HUVECs.

PubMed

Chiu, Jen-Hwey; Chen, Fang-Pey; Tsai, Yi-Fang; Lin, Man-Ting; Tseng, Ling-Ming; Shyr, Yi-Ming

2017-08-12

Our previous study demonstrated that an up-regulation of the Brain-Derived Neurotrophic Factor (BDNF) signaling pathway is involved the mechanism causing the recurrence of triple negative breast cancer. The aim of this study is to investigate the effects of commonly used Chinese medicinal herbs on MDA-MB-231 and HUVEC cells and how they interact with BDNF. Human TNBC MDA-MB-231 cells and human endothelial HUVEC cells were used to explore the effect of commonly used Chinese herbal medicines on cancer cells alone, on endothelial cells alone and on cancer cell/endothelial cell interactions; this was done via functional studies, including migration and invasion assays. Furthermore, Western blot analysis and real-time PCR investigations were also used to investigate migration signal transduction, invasion signal transduction, and angiogenic signal transduction in these systems. Finally, the effect of the Chinese medicinal herbs on cancer cell/endothelial cell interactions was assessed using co-culture and ELISA. In terms of autoregulation, BDNF up-regulated TrkB gene expression in both MDA-MB-231 and HUVEC cells. Furthermore, BDNF enhanced migration by MDA-MB-231 cells via Rac, Cdc42 and MMP, while also increasing the migration of HUVEC cells via MMP and COX-2 expression. As measured by ELISA, the Chinese herbal medicinal herbs A. membranaceus, P. lactiflora, L. chuanxiong, P. suffruticosa and L. lucidum increased BDNF secretion by MDA-MB-231 cells. Similarly, using a co-culture system with MDA-MB-231 cells, A. membranaceus and L. lucidum modulated BDNF-TrkB signaling by HUVEC cells. We conclude that BDNF plays an important role in the metastatic interaction between MDA-MB-231 and HUVEC cells. Some Chinese medicinal herbs are able to enhance the BDNF-related metastatic potential of the interaction between cancer cells and endothelial cells. These findings provide important information that should help with the development of integrated medical therapies for breast cancer patients.

Increased expression of c-Ski as a co-repressor in transforming growth factor-beta signaling correlates with progression of esophageal squamous cell carcinoma.

PubMed

Fukuchi, Minoru; Nakajima, Masanobu; Fukai, Yasuyuki; Miyazaki, Tatsuya; Masuda, Norihiro; Sohda, Makoto; Manda, Ryokuhei; Tsukada, Katsuhiko; Kato, Hiroyuki; Kuwano, Hiroyuki

2004-03-01

Transforming growth factor-beta (TGF-beta) regulates cell growth inhibition, and inactivation of the TGF-beta signaling pathway contributes to tumor development. In our previous study, altered expression of TGF-beta, TGF-beta-specific receptors and Smad4 was shown to correlate with tumor progression in esophageal squamous cell carcinoma (SCC). These components, however, were maintained normally in some patients with esophageal SCC. In our study, the mechanism by which aggressive esophageal SCC maintains these components was investigated, with particular emphasis on the participation of c-Ski and SnoN as transcriptional co-repressors in TGF-beta signaling. Immunohistochemistry for c-Ski and SnoN was carried out on surgical specimens obtained from 80 patients with esophageal SCC. The expression of c-Ski and SnoN was also studied in 6 established cell lines derived from esophageal SCC and compared to an immortalized human esophageal cell line by Western blotting. High levels of expression of c-Ski, detected immunohistologically, were found to correlate with depth of invasion (p = 0.0080) and pathologic stage (p = 0.0447). There was, however, no significant correlation between expression of SnoN and clinicopathologic characteristics. A significant correlation between c-Ski and TGF-beta expression was observed. Moreover, in patients with TGF-beta negative expression, the survival rates of patients with c-Ski positive expression were significantly lower than those of patients with c-Ski negative expression (p = 0.0486). c-Ski was expressed at a high level in 5 of 6 cell lines derived from esophageal SCC compared to immortalized esophageal keratinocytes. Furthermore, the cyclin-dependent kinase (CDK) inhibitor, p21 that was up-regulated by TGF-beta signaling was expressed at a low level in the 5 cell lines. The expression of c-Ski protein as a transcriptional co-repressor in TGF-beta signaling seems to be correlated with tumor progression of esophageal SCC. Copyright 2003 Wiley-Liss, Inc.

Epidermal Growth Factor and Interleukin-1β Utilize Divergent Signaling Pathways to Synergistically Upregulate Cyclooxygenase-2 Gene Expression in Human Amnion-Derived WISH Cells1

PubMed Central

Ackerman, William E.; Rovin, Brad H.; Kniss, Douglas A.

2006-01-01

In human parturition, uterotonic prostaglandins (PGs) arise predominantly via increased expression of cyclooxygenase-2 (COX-2 [also known as prostaglandin synthase 2]) within intra-uterine tissues. Interleukin-1 (IL-1) and epidermal growth factor (EGF), both inducers of COX-2 transcription, are among numerous factors that accumulate within amniotic fluid with advancing gestation. It was previously demonstrated that EGF could potentiate IL-1β-driven PGE2 production in amnion and amnion-derived (WISH) cells. To define the mechanism for this observation, we hypothesized that EGF and IL-1β might exhibit synergism in regulating COX-2 gene expression. In WISH cells, combined treatment with EGF and IL-1β resulted in a greater-than-additive increase in COX-2 mRNA relative to challenge with either agent independently. Augmentation of IL-1β-induced transactivation by EGF was not observed in cells harboring reporter plasmids bearing nuclear factor-kappa B (NFκB) regulatory elements alone, but was evident when a fragment (−891/+9) of the COX-2 gene 5′-promoter was present. Both agents transiently activated intermediates of multiple signaling pathways potentially involved in the regulation of COX-2 gene expression. The 26 S proteasome inhibitor, MG-132, selectively abrogated IL-1β-driven NFκB activation and COX-2 mRNA expression. Only pharmacologic blockade of the p38 mitogen-activated protein kinase eliminated COX-2 expression following EGF stimulation. We conclude that EGF and IL-1β appear to signal through different signaling cascades leading to COX-2 gene expression. IL-1β employs the NFκB pathway predominantly, while the spectrum of EGF signaling is broader and includes p38 kinase. The synergism observed between IL-1β and EGF does not rely on augmented NFκB function, but rather, occurs through differential use of independent response elements within the COX-2 promoter. PMID:15329330

Illumination-based synchronization of high-speed vision sensors.

PubMed

Hou, Lei; Kagami, Shingo; Hashimoto, Koichi

2010-01-01

To acquire images of dynamic scenes from multiple points of view simultaneously, the acquisition time of vision sensors should be synchronized. This paper describes an illumination-based synchronization method derived from the phase-locked loop (PLL) algorithm. Incident light to a vision sensor from an intensity-modulated illumination source serves as the reference signal for synchronization. Analog and digital computation within the vision sensor forms a PLL to regulate the output signal, which corresponds to the vision frame timing, to be synchronized with the reference. Simulated and experimental results show that a 1,000 Hz frame rate vision sensor was successfully synchronized with 32 μs jitters.

Lipid antigens in immunity

PubMed Central

Dowds, C. Marie; Kornell, Sabin-Christin

2014-01-01

Lipids are not only a central part of human metabolism but also play diverse and critical roles in the immune system. As such, they can act as ligands of lipid-activated nuclear receptors, control inflammatory signaling through bioactive lipids such as prostaglandins, leukotrienes, lipoxins, resolvins, and protectins, and modulate immunity as intracellular phospholipid- or sphingolipid-derived signaling mediators. In addition, lipids can serve as antigens and regulate immunity through the activation of lipid-reactive T cells, which is the topic of this review. We will provide an overview of the mechanisms of lipid antigen presentation, the biology of lipid-reactive T cells, and their contribution to immunity. PMID:23999493

Lysosomal Two-pore Channel Subtype 2 (TPC2) Regulates Skeletal Muscle Autophagic Signaling*

PubMed Central

Lin, Pei-Hui; Duann, Pu; Komazaki, Shinji; Park, Ki Ho; Li, Haichang; Sun, Mingzhai; Sermersheim, Mathew; Gumpper, Kristyn; Parrington, John; Galione, Antony; Evans, A. Mark; Zhu, Michael X.; Ma, Jianjie

2015-01-01

Postnatal skeletal muscle mass is regulated by the balance between anabolic protein synthesis and catabolic protein degradation, and muscle atrophy occurs when protein homeostasis is disrupted. Autophagy has emerged as critical in clearing dysfunctional organelles and thus in regulating protein turnover. Here we show that endolysosomal two-pore channel subtype 2 (TPC2) contributes to autophagy signaling and protein homeostasis in skeletal muscle. Muscles derived from Tpcn2−/− mice exhibit an atrophic phenotype with exacerbated autophagy under starvation. Compared with wild types, animals lacking TPC2 demonstrated an enhanced autophagy flux characterized by increased accumulation of autophagosomes upon combined stress induction by starvation and colchicine treatment. In addition, deletion of TPC2 in muscle caused aberrant lysosomal pH homeostasis and reduced lysosomal protease activity. Association between mammalian target of rapamycin and TPC2 was detected in skeletal muscle, allowing for appropriate adjustments to cellular metabolic states and subsequent execution of autophagy. TPC2 therefore impacts mammalian target of rapamycin reactivation during the process of autophagy and contributes to maintenance of muscle homeostasis. PMID:25480788

Tif1γ regulates the TGF-β1 receptor and promotes physiological aging of hematopoietic stem cells.

PubMed

Quéré, Ronan; Saint-Paul, Laetitia; Carmignac, Virginie; Martin, Romain Z; Chrétien, Marie-Lorraine; Largeot, Anne; Hammann, Arlette; Pais de Barros, Jean-Paul; Bastie, Jean-Noël; Delva, Laurent

2014-07-22

The hematopoietic system declines with age. Myeloid-biased differentiation and increased incidence of myeloid malignancies feature aging of hematopoietic stem cells (HSCs), but the mechanisms involved remain uncertain. Here, we report that 4-mo-old mice deleted for transcription intermediary factor 1γ (Tif1γ) in HSCs developed an accelerated aging phenotype. To reinforce this result, we also show that Tif1γ is down-regulated in HSCs during aging in 20-mo-old wild-type mice. We established that Tif1γ controls TGF-β1 receptor (Tgfbr1) turnover. Compared with young HSCs, Tif1γ(-/-) and old HSCs are more sensitive to TGF-β signaling. Importantly, we identified two populations of HSCs specifically discriminated by Tgfbr1 expression level and provided evidence of the capture of myeloid-biased (Tgfbr1(hi)) and myeloid-lymphoid-balanced (Tgfbr1(lo)) HSCs. In conclusion, our data provide a new paradigm for Tif1γ in regulating the balance between lymphoid- and myeloid-derived HSCs through TGF-β signaling, leading to HSC aging.

PDGF-AA promotes osteogenic differentiation and migration of mesenchymal stem cell by down-regulating PDGFRα and derepressing BMP-Smad1/5/8 signaling.

PubMed

Li, Anna; Xia, Xuechun; Yeh, James; Kua, Huiyi; Liu, Huijuan; Mishina, Yuji; Hao, Aijun; Li, Baojie

2014-01-01

Platelet-derived growth factors (PDGFs) play important roles in skeletal development and bone fracture healing, yet how PDGFs execute their functions remains incompletely understood. Here we show that PDGF-AA, but not -AB or -BB, could activate the BMP-Smad1/5/8 pathway in mesenchymal stem cells (MSCs), which requires BMPRIA as well as PDGFRα. PDGF-AA promotes MSC osteogenic differentiation through the BMP-Smad1/5/8-Runx2/Osx axis and MSC migration via the BMP-Smad1/5/8-Twist1/Atf4 axis. Mechanistic studies show that PDGF-AA activates BMP-Smad1/5/8 signaling by feedback down-regulating PDGFRα, which frees BMPRI and allows for BMPRI-BMPRII complex formation to activate smad1/5/8, using BMP molecules in the microenvironment. This study unravels a physical and functional interaction between PDGFRα and BMPRI, which plays an important role in MSC differentiation and migration, and establishes a link between PDGF-AA and BMPs pathways, two essential regulators of embryonic development and tissue homeostasis.

Effects of Pregnane Glycosides on Food Intake Depend on Stimulation of the Melanocortin Pathway and BDNF in an Animal Model

PubMed Central

Komarnytsky, Slavko; Esposito, Debora; Rathinasabapathy, Thirumurugan; Poulev, Alexander; Raskin, Ilya

2013-01-01

Pregnane glycosides appear to modulate food intake by possibly affecting the hypothalamic feeding circuits; however, the mechanisms of the appetite-regulating effect of pregnane glycosides remain obscure. Here, we show that pregnane glycoside-enriched extracts from swamp milkweed Asclepias incarnata at 25–100 mg/kg daily attenuated food intake (up to 47.1 ± 8.5% less than controls) and body weight gain in rats (10% for males and 9% for females, respectively) by activating melanocortin signaling and inhibiting gastric emptying. The major milkweed pregnane glycoside, ikemagenin, exerted its appetite-regulating effect by decreasing levels of agouti-related protein (0.6-fold) but not NPY satiety peptides. Ikemagenin treatment also increased secretion of brain-derived neurotropic factor (BDNF) downstream of melanocortin receptors in the hypothalamus (1.4-fold) and in the C6 rat glioma cell culture in vitro (up to 6-fold). These results support the multimodal effects of pregnane glycosides on feeding regulation, which depends on the activity of the melanocortin signaling pathway and BDNF. PMID:23308358

Effects of pregnane glycosides on food intake depend on stimulation of the melanocortin pathway and BDNF in an animal model.

PubMed

Komarnytsky, Slavko; Esposito, Debora; Rathinasabapathy, Thirumurugan; Poulev, Alexander; Raskin, Ilya

2013-02-27

Pregnane glycosides appear to modulate food intake by possibly affecting the hypothalamic feeding circuits; however, the mechanisms of the appetite-regulating effect of pregnane glycosides remain obscure. Here, we show that pregnane glycoside-enriched extracts from swamp milkweed Asclepias incarnata at 25-100 mg/kg daily attenuated food intake (up to 47.1 ± 8.5% less than controls) and body weight gain in rats (10% for males and 9% for females, respectively) by activating melanocortin signaling and inhibiting gastric emptying. The major milkweed pregnane glycoside, ikemagenin, exerted its appetite-regulating effect by decreasing levels of agouti-related protein (0.6-fold) but not NPY satiety peptides. Ikemagenin treatment also increased secretion of brain-derived neurotropic factor (BDNF) downstream of melanocortin receptors in the hypothalamus (1.4-fold) and in the C6 rat glioma cell culture in vitro (up to 6-fold). These results support the multimodal effects of pregnane glycosides on feeding regulation, which depends on the activity of the melanocortin signaling pathway and BDNF.

Desert hedgehog promotes ischemia-induced angiogenesis by ensuring peripheral nerve survival.

PubMed

Renault, Marie-Ange; Chapouly, Candice; Yao, Qinyu; Larrieu-Lahargue, Frédéric; Vandierdonck, Soizic; Reynaud, Annabel; Petit, Myriam; Jaspard-Vinassa, Béatrice; Belloc, Isabelle; Traiffort, Elisabeth; Ruat, Martial; Duplàa, Cécile; Couffinhal, Thierry; Desgranges, Claude; Gadeau, Alain-Pierre

2013-03-01

Blood vessel growth and patterning have been shown to be regulated by nerve-derived signals. Desert hedgehog (Dhh), one of the Hedgehog family members, is expressed by Schwann cells of peripheral nerves. The purpose of this study was to investigate the contribution of Dhh to angiogenesis in the setting of ischemia. We induced hindlimb ischemia in wild-type and Dhh(-/-) mice. First, we found that limb perfusion is significantly impaired in the absence of Dhh. This effect is associated with a significant decrease in capillary and artery density in Dhh(-/-). By using mice in which the Hedgehog signaling pathway effector Smoothened was specifically invalidated in endothelial cells, we demonstrated that Dhh does not promote angiogenesis by a direct activation of endothelial cells. On the contrary, we found that Dhh promotes peripheral nerve survival in the ischemic muscle and, by doing so, maintains the pool of nerve-derived proangiogenic factors. Consistently, we found that denervation of the leg, immediately after the onset of ischemia, severely impairs ischemia-induced angiogenesis and decreases expression of vascular endothelial growth factor A, angiopoietin 1, and neurotrophin 3 in the ischemic muscle. This study demonstrates the crucial roles of nerves and factors regulating nerve physiology in the setting of ischemia-induced angiogenesis.

Interstitial Fluid Flow Increases Hepatocellular Carcinoma Cell Invasion through CXCR4/CXCL12 and MEK/ERK Signaling

PubMed Central

2015-01-01

Hepatocellular carcinoma (HCC) is the most common form of liver cancer (~80%), and it is one of the few cancer types with rising incidence in the United States. This highly invasive cancer is very difficult to detect until its later stages, resulting in limited treatment options and low survival rates. There is a dearth of knowledge regarding the mechanisms associated with the effects of biomechanical forces such as interstitial fluid flow (IFF) on hepatocellular carcinoma invasion. We hypothesized that interstitial fluid flow enhanced hepatocellular carcinoma cell invasion through chemokine-mediated autologous chemotaxis. Utilizing a 3D in vitro invasion assay, we demonstrated that interstitial fluid flow promoted invasion of hepatocellular carcinoma derived cell lines. Furthermore, we showed that autologous chemotaxis influences this interstitial fluid flow-induced invasion of hepatocellular carcinoma derived cell lines via the C-X-C chemokine receptor type 4 (CXCR4)/C-X-C motif chemokine 12 (CXCL12) signaling axis. We also demonstrated that mitogen-activated protein kinase (MEK)/extracellular signal-regulated kinase (ERK) signaling affects interstitial fluid flow-induced invasion; however, this pathway was separate from CXCR4/CXCL12 signaling. This study demonstrates, for the first time, the potential role of interstitial fluid flow in hepatocellular carcinoma invasion. Uncovering the mechanisms that control hepatocellular carcinoma invasion will aid in enhancing current liver cancer therapies and provide better treatment options for patients. PMID:26560447

Activin B regulates adipose-derived mesenchymal stem cells to promote skin wound healing via activation of the MAPK signaling pathway.

PubMed

Zhang, Lei; Xu, Pengcheng; Wang, Xueer; Zhang, Min; Yan, Yuan; Chen, Yinghua; Zhang, Lu; Zhang, Lin

2017-06-01

Adipose-derived stem cells (ADSCs) are multipotent stromal cells that can differentiate into a variety of cell types, including skin cells, and they can provide an abundant source of cells for skin tissue engineering and skin wound healing. The purpose of this study is to explore the therapeutic effects of activin B in combination with ADSCs and the possible signaling mechanism. In this study, we found that activin B was able to promote ADSC migration by inducing actin stress fiber formation in vitro. In vivo, activin B in combination with ADSCs was capable of enhancing α-SMA expression and wound closure. This combined treatment also promoted fibroblast and keratinocyte proliferation and accelerated re-epithelialization and collagen deposition. Moreover, activin B in combination with ADSCs boosted angiogenesis in the wound area. Further study of the mechanism revealed that activation of JNK and ERK signaling, but not p38 signaling, were required for activin B-induced ADSC actin stress fiber formation and cell migration. These results showed that activin B was able to activate JNK and ERK signaling pathways to induce actin stress fiber formation and ADSC migration to promote wound healing. These results suggest that combined treatment with activin B and ADSCs is a promising therapeutic strategy for the management of serious skin wounds. Copyright © 2017. Published by Elsevier Ltd.

MicroRNA-Mediated Down-Regulation of Apoptosis Signal-Regulating Kinase 1 (ASK1) Attenuates the Apoptosis of Human Mesenchymal Stem Cells (MSCs) Transplanted into Infarcted Heart.

PubMed

Lee, Chang Youn; Shin, Sunhye; Lee, Jiyun; Seo, Hyang-Hee; Lim, Kyu Hee; Kim, Hyemin; Choi, Jung-Won; Kim, Sang Woo; Lee, Seahyung; Lim, Soyeon; Hwang, Ki-Chul

2016-10-20

Stem cell therapy using adult stem cells, such as mesenchymal stem cells (MSCs) has produced some promising results in treating the damaged heart. However, the low survival rate of MSCs after transplantation is still one of the crucial factors that limit the therapeutic effect of stem cells. In the damaged heart, oxidative stress due to reactive oxygen species (ROS) production can cause the death of transplanted MSCs. Apoptosis signal-regulating kinase 1 (ASK1) has been implicated in the development of oxidative stress-related pathologic conditions. Thus, we hypothesized that down-regulation of ASK1 in human MSCs (hMSCs) might attenuate the post-transplantation death of MSCs. To test this hypothesis, we screened microRNAs (miRNAs) based on a miRNA-target prediction database and empirical data and investigated the anti-apoptotic effect of selected miRNAs on human adipose-derived stem cells (hASCs) and on rat myocardial infarction (MI) models. Our data indicated that miRNA-301a most significantly suppressed ASK1 expression in hASCs. Apoptosis-related genes were significantly down-regulated in miRNA-301a-enriched hASCs exposed to hypoxic conditions. Taken together, these data show that miRNA-mediated down-regulation of ASK1 protects MSCs during post-transplantation, leading to an increase in the efficacy of MSC-based cell therapy.

Energy Balance Regulating Neuropeptides Are Expressed through Pregnancy and Regulated by Interleukin-6 Deficiency in Mouse Placenta

PubMed Central

Pazos, Patricia; Lima, Luis; Diéguez, Carlos; García, María C.

2014-01-01

The placenta produces a number of signaling molecules including metabolic and reproductive hormones as well as several inflammatory mediators. Among them, Interleukin-6 (IL-6), a well-known immune and metabolic regulator, acts peripherally modulating metabolic function and centrally increasing energy expenditure and reducing body fat. IL-6 interacts with key hypothalamic neuropeptidergic systems controlling energy homeostasis such as those producing the orexigenic/anabolic: neuropeptide Y (NPY) and agouti-related peptide (AgRP) and anorectic/catabolic neuropeptides: proopiomelanocortin (POMC) and cocaine and amphetamine regulated transcript (CART). Human and rat placenta have been identified as source of these neuropeptides, but their expression and regulation in murine placental tissues remain unknown. Therefore, placental mRNA levels of IL-6, NPY, AgRP, POMC, and CART at different pregnancy stages (gestational days 13, 15, and 18) were analyzed by real time PCR, as were the effect of IL-6 deficiency (IL-6 knockout mice) on their placental expression. Our results showed that placenta-derived neuropeptides were regulated by gestational age and IL-6 throughout the second half of mouse pregnancy. These data suggest that IL-6 may participate in the fine tune control of energy balance during pregnancy by extending its action as a metabolic signal to the main organ at the fetomaternal interface: the placenta. PMID:24744782

Stability analysis and compensation of a boost regulator with two-loop control

NASA Technical Reports Server (NTRS)

Wester, G. W.

1974-01-01

A useful stability measure has been demonstrated by Wester (1973) for switching regulators with a single feedback loop by applying the Nyquist criterion to the approximate loop gain determined by a time-averaging technique. This approach is extended and applied to the characterization, stability analysis, and compensation design of a switching regulator with two-loop control. The role and relative significance of each control loop is clarified on the basis of a description of circuit operation, and the major and minor loops are identified. In view of the inapplicability of linear feedback theory, describing functions of the feedback loops and power stage are derived, using small-signal analysis. Several phenomena revealed from an analysis of the major loop gain are discussed.

The p38 mitogen-activated protein kinase signaling pathway is involved in regulating low-density lipoprotein receptor-related protein 1-mediated β-amyloid protein internalization in mouse brain.

PubMed

Ma, Kai-Ge; Lv, Jia; Hu, Xiao-Dan; Shi, Li-Li; Chang, Ke-Wei; Chen, Xin-Lin; Qian, Yi-Hua; Yang, Wei-Na; Qu, Qiu-Min

2016-07-01

Alzheimer's disease (AD) is one of the most common neurodegenerative diseases. Recently, increasing evidence suggests that intracellular β-amyloid protein (Aβ) alone plays a pivotal role in the progression of AD. Therefore, understanding the signaling pathway and proteins that control Aβ internalization may provide new insight for regulating Aβ levels. In the present study, the regulation of Aβ internalization by p38 mitogen-activated protein kinases (MAPK) through low-density lipoprotein receptor-related protein 1 (LRP1) was analyzed in vivo. The data derived from this investigation revealed that Aβ1-42 were internalized by neurons and astrocytes in mouse brain, and were largely deposited in mitochondria and lysosomes, with some also being found in the endoplasmic reticulum. Aβ1-42-LRP1 complex was formed during Aβ1-42 internalization, and the p38 MAPK signaling pathway was activated by Aβ1-42 via LRP1. Aβ1-42 and LRP1 were co- localized in the cells of parietal cortex and hippocampus. Furthermore, the level of LRP1-mRNA and LRP1 protein involved in Aβ1-42 internalization in mouse brain. The results of this investigation demonstrated that Aβ1-42 induced an LRP1-dependent pathway that related to the activation of p38 MAPK resulting in internalization of Aβ1-42. These results provide evidence supporting a key role for the p38 MAPK signaling pathway which is involved in the regulation of Aβ1-42 internalization in the parietal cortex and hippocampus of mouse through LRP1 in vivo. Copyright © 2016 Elsevier Ltd. All rights reserved.

Liver X receptor regulates hepatic nuclear O-GlcNAc signaling and carbohydrate responsive element-binding protein activity[S

PubMed Central

Bindesbøll, Christian; Fan, Qiong; Nørgaard, Rikke C.; MacPherson, Laura; Ruan, Hai-Bin; Wu, Jing; Pedersen, Thomas Å.; Steffensen, Knut R.; Yang, Xiaoyong; Matthews, Jason; Mandrup, Susanne; Nebb, Hilde I.; Grønning-Wang, Line M.

2015-01-01

Liver X receptor (LXR)α and LXRβ play key roles in hepatic de novo lipogenesis through their regulation of lipogenic genes, including sterol regulatory element-binding protein (SREBP)-1c and carbohydrate responsive element-binding protein (ChREBP). LXRs activate lipogenic gene transcription in response to feeding, which is believed to be mediated by insulin. We have previously shown that LXRs are targets for glucose-hexosamine-derived O-linked β-N-acetylglucosamine (O-GlcNAc) modification enhancing their ability to regulate SREBP-1c promoter activity in vitro. To elucidate insulin-independent effects of feeding on LXR-mediated lipogenic gene expression in vivo, we subjected control and streptozotocin-treated LXRα/β+/+ and LXRα/β−/− mice to a fasting-refeeding regime. We show that under hyperglycemic and hypoinsulinemic conditions, LXRs maintain their ability to upregulate the expression of glycolytic and lipogenic enzymes, including glucokinase (GK), SREBP-1c, ChREBPα, and the newly identified shorter isoform ChREBPβ. Furthermore, glucose-dependent increases in LXR/retinoid X receptor-regulated luciferase activity driven by the ChREBPα promoter was mediated, at least in part, by O-GlcNAc transferase (OGT) signaling in Huh7 cells. Moreover, we show that LXR and OGT interact and colocalize in the nucleus and that loss of LXRs profoundly reduced nuclear O-GlcNAc signaling and ChREBPα promoter binding activity in vivo. In summary, our study provides evidence that LXRs act as nutrient and glucose metabolic sensors upstream of ChREBP by modulating GK expression, nuclear O-GlcNAc signaling, and ChREBP expression and activity. PMID:25724563

Downstream effects of ROCK signaling in cultured human corneal stromal cells: microarray analysis of gene expression.

PubMed

Harvey, Stephen A K; Anderson, Susan C; SundarRaj, Nirmala

2004-07-01

Rho-associated coiled-coil-containing protein kinase (ROCK) is a downstream target of Rho GTPase signaling and regulates the assembly of stress fibers. Previous reports indicate that Rho/ROCK signaling is involved in the regulation of several cellular processes, some of which may be cell-type specific and are probably critical to corneal stromal cell activation. The present study identified ROCK-regulated gene expression in corneal stromal cells. Corneal stromal cells derived from eyes of three different donors were cultured to yield the following designated phenotypes: baseline fibroblasts (DMEM with 10% serum), activated fibroblasts (10% serum+bFGF+heparin), and myofibroblasts (1% serum+TGF-beta 1). Cells were exposed to the ROCK inhibitor Y-27632 or vehicle for 12 hours, and transcript levels altered by ROCK inhibition were identified with oligonucleotide microarrays (GeneChips; Affymetrix, Santa Clara, CA). In these phenotypes, Y-27632 caused marked (twofold or more) increases or decreases in 14/4, 12/3, and 15/10 transcripts. In both fibroblast groups Y-27632-treatment increased expression of endothelin receptors and of parathyroid hormone-like hormone. The upregulation of alpha-smooth muscle actin in myofibroblasts was attenuated by Y-27632. Combining data from all groups identified ROCK-supported (Y-27632 inhibitable) expression of 10 transcripts, including ribonucleotide reductase M2, the cyclin B1-CDC2-CKS2 system, and four mitotic spindle-associated proteins. ROCK inhibition causes broad inhibition of DNA synthesis and mitosis and causes changes that are different between (bFGF-activated) fibroblasts and (TGF-beta 1-induced) myofibroblasts. Thus, Rho/ROCK signaling regulates both common and distinct downstream events in corneal stromal cells activated (differentiated) to fibroblast or myofibroblast phenotype.

Functional malignant cell heterogeneity in pancreatic neuroendocrine tumors revealed by targeting of PDGF-DD.

PubMed

Cortez, Eliane; Gladh, Hanna; Braun, Sebastian; Bocci, Matteo; Cordero, Eugenia; Björkström, Niklas K; Miyazaki, Hideki; Michael, Iacovos P; Eriksson, Ulf; Folestad, Erika; Pietras, Kristian

2016-02-16

Intratumoral heterogeneity is an inherent feature of most human cancers and has profound implications for cancer therapy. As a result, there is an emergent need to explore previously unmapped mechanisms regulating distinct subpopulations of tumor cells and to understand their contribution to tumor progression and treatment response. Aberrant platelet-derived growth factor receptor beta (PDGFRβ) signaling in cancer has motivated the development of several antagonists currently in clinical use, including imatinib, sunitinib, and sorafenib. The discovery of a novel ligand for PDGFRβ, platelet-derived growth factor (PDGF)-DD, opened the possibility of a previously unidentified signaling pathway involved in tumor development. However, the precise function of PDGF-DD in tumor growth and invasion remains elusive. Here, making use of a newly generated Pdgfd knockout mouse, we reveal a functionally important malignant cell heterogeneity modulated by PDGF-DD signaling in pancreatic neuroendocrine tumors (PanNET). Our analyses demonstrate that tumor growth was delayed in the absence of signaling by PDGF-DD. Surprisingly, ablation of PDGF-DD did not affect the vasculature or stroma of PanNET; instead, we found that PDGF-DD stimulated bulk tumor cell proliferation by induction of paracrine mitogenic signaling between heterogeneous malignant cell clones, some of which expressed PDGFRβ. The presence of a subclonal population of tumor cells characterized by PDGFRβ expression was further validated in a cohort of human PanNET. In conclusion, we demonstrate a previously unrecognized heterogeneity in PanNET characterized by signaling through the PDGF-DD/PDGFRβ axis.

Functional malignant cell heterogeneity in pancreatic neuroendocrine tumors revealed by targeting of PDGF-DD

PubMed Central

Cortez, Eliane; Gladh, Hanna; Braun, Sebastian; Bocci, Matteo; Cordero, Eugenia; Björkström, Niklas K.; Miyazaki, Hideki; Michael, Iacovos P.; Eriksson, Ulf; Folestad, Erika; Pietras, Kristian

2016-01-01

Intratumoral heterogeneity is an inherent feature of most human cancers and has profound implications for cancer therapy. As a result, there is an emergent need to explore previously unmapped mechanisms regulating distinct subpopulations of tumor cells and to understand their contribution to tumor progression and treatment response. Aberrant platelet-derived growth factor receptor beta (PDGFRβ) signaling in cancer has motivated the development of several antagonists currently in clinical use, including imatinib, sunitinib, and sorafenib. The discovery of a novel ligand for PDGFRβ, platelet-derived growth factor (PDGF)-DD, opened the possibility of a previously unidentified signaling pathway involved in tumor development. However, the precise function of PDGF-DD in tumor growth and invasion remains elusive. Here, making use of a newly generated Pdgfd knockout mouse, we reveal a functionally important malignant cell heterogeneity modulated by PDGF-DD signaling in pancreatic neuroendocrine tumors (PanNET). Our analyses demonstrate that tumor growth was delayed in the absence of signaling by PDGF-DD. Surprisingly, ablation of PDGF-DD did not affect the vasculature or stroma of PanNET; instead, we found that PDGF-DD stimulated bulk tumor cell proliferation by induction of paracrine mitogenic signaling between heterogeneous malignant cell clones, some of which expressed PDGFRβ. The presence of a subclonal population of tumor cells characterized by PDGFRβ expression was further validated in a cohort of human PanNET. In conclusion, we demonstrate a previously unrecognized heterogeneity in PanNET characterized by signaling through the PDGF-DD/PDGFRβ axis. PMID:26831065

Role of β-Oxidation in Jasmonate Biosynthesis and Systemic Wound Signaling in TomatoW⃞

PubMed Central

Li, Chuanyou; Schilmiller, Anthony L.; Liu, Guanghui; Lee, Gyu In; Jayanty, Sastry; Sageman, Carolyn; Vrebalov, Julia; Giovannoni, James J.; Yagi, Kaori; Kobayashi, Yuichi; Howe, Gregg A.

2005-01-01

Jasmonic acid (JA) is a lipid-derived signal that regulates plant defense responses to biotic stress. Here, we report the characterization of a JA-deficient mutant of tomato (Lycopersicon esculentum) that lacks local and systemic expression of defensive proteinase inhibitors (PIs) in response to wounding. Map-based cloning studies demonstrated that this phenotype results from loss of function of an acyl-CoA oxidase (ACX1A) that catalyzes the first step in the peroxisomal β-oxidation stage of JA biosynthesis. Recombinant ACX1A exhibited a preference for C12 and C14 straight-chain acyl-CoAs and also was active in the metabolism of C18 cyclopentanoid-CoA precursors of JA. The overall growth, development, and reproduction of acx1 plants were similar to wild-type plants. However, the mutant was compromised in its defense against tobacco hornworm (Manduca sexta) attack. Grafting experiments showed that loss of ACX1A function disrupts the production of the transmissible signal for wound-induced PI expression but does not affect the recognition of this signal in undamaged responding leaves. We conclude that ACX1A is essential for the β-oxidation stage of JA biosynthesis and that JA or its derivatives is required both for antiherbivore resistance and the production of the systemic wound signal. These findings support a role for peroxisomes in the production of lipid-based signaling molecules that promote systemic defense responses. PMID:15722469

Ethylene responsive factor ERF110 mediates ethylene-regulated transcription of a sex determination-related orthologous gene in two Cucumis species.

PubMed

Tao, Qianyi; Niu, Huanhuan; Wang, Zhongyuan; Zhang, Wenhui; Wang, Hu; Wang, Shenhao; Zhang, Xian; Li, Zheng

2018-05-25

In plants, unisexual flowers derived from developmental sex determination form separate stamens and pistils that facilitate cross pollination. In cucumber and melon, ethylene plays a key role in sex determination. Six sex determination-related genes have been identified in ethylene biosynthesis in these Cucumis species. The interactions among these genes are thought to involve ethylene signaling; however, the underlying mechanism of regulation remains unknown. In this study, hormone treatment and qPCR assays were used to confirm expression of these sex determination-related genes in cucumber and melon is ethylene sensitive. RNA-Seq analysis subsequently helped identify the ethylene responsive factor (ERF) gene, CsERF110, related to ethylene signaling and sex determination. CsERF110 and its melon ortholog, CmERF110, shared a conserved AP2/ERF domain and showed ethylene-sensitive expression. Yeast one-hybrid and ChIP-PCR assays further indicated that CsERF110 bound to at least two sites in the promoter fragment of CsACS11, while transient transformation analysis showed that CsERF110 and CmERF110 enhance CsACS11 and CmACS11 promoter activity, respectively. Taken together, these findings suggest that CsERF110 and CmERF110 respond to ethylene signaling, mediating ethylene-regulated transcription of CsACS11 and CmACS11 in cucumber and melon, respectively. Furthermore, the mechanism involved in its regulation is thought to be conserved in these two Cucumis species.

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

Shen, Longxiang; Glowacki, Julie; Zhou, Shuanhu, E-mail: szhou@rics.bwh.harvard.edu

The WNT signaling pathway plays important roles in the self-renewal and differentiation of mesenchymal stem cells (MSCs). Little is known about WNT signaling in adipocyte differentiation of human MSCs. In this study, we tested the hypothesis that canonical and non-canonical WNTs differentially regulate in vitro adipocytogenesis in human MSCs. The expression of adipocyte gene PPAR{gamma}2, lipoprotein lipase, and adipsin increased during adipocytogenesis of hMSCs. Simultaneously, the expression of canonical WNT2, 10B, 13, and 14 decreased, whereas non-canonical WNT4 and 11 increased, and WNT5A was unchanged. A small molecule WNT mimetic, SB-216763, increased accumulation of {beta}-catenin protein, inhibited induction of WNT4more » and 11 and inhibited adipocytogenesis. In contrast, knockdown of {beta}-catenin with siRNA resulted in spontaneous adipocytogenesis. These findings support the view that canonical WNT signaling inhibits and non-canonical WNT signaling promotes adipocytogenesis in adult human marrow-derived mesenchymal stem cells.« less

Instructing cells with programmable peptide DNA hybrids

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

Freeman, Ronit; Stephanopoulos, Nicholas; Alvarez, Zaida

The native extracellular matrix is a space in which signals can be displayed dynamically and reversibly, positioned with nanoscale precision, and combined synergistically to control cell function. Here we describe a molecular system that can be programmed to control these three characteristics. In this approach we immobilize peptide-DNA (P-DNA) molecules on a surface through complementary DNA tethers directing cells to adhere and spread reversibly over multiple cycles. The DNA can also serve as a molecular ruler to control the distance-dependent synergy between two peptides. Finally, we use two orthogonal DNA handles to regulate two different bioactive signals, with the abilitymore » to independently up- or downregulate each over time. This enabled us to discover that neural stem cells, derived from the murine spinal cord and organized as neurospheres, can be triggered to migrate out in response to an exogenous signal but then regroup into a neurosphere as the signal is removed.« less

Neurotrophic factors switch between two signaling pathways that trigger axonal growth.

PubMed

Paveliev, Mikhail; Lume, Maria; Velthut, Agne; Phillips, Matthew; Arumäe, Urmas; Saarma, Mart

2007-08-01

Integration of multiple inputs from the extracellular environment, such as extracellular matrix molecules and growth factors, is a crucial process for cell function and information processing in multicellular organisms. Here we demonstrate that co-stimulation of dorsal root ganglion neurons with neurotrophic factors (NTFs) - glial-cell-line-derived neurotrophic factor, neurturin or nerve growth factor - and laminin leads to axonal growth that requires activation of Src family kinases (SFKs). A different, SFK-independent signaling pathway evokes axonal growth on laminin in the absence of the NTFs. By contrast, axonal branching is regulated by SFKs both in the presence and in the absence of NGF. We propose and experimentally verify a Boolean model of the signaling network triggered by NTFs and laminin. Our results demonstrate that NTFs provide an environmental cue that triggers a switch between separate pathways in the cell signaling network.

Instructing cells with programmable peptide DNA hybrids

DOE PAGES

Freeman, Ronit; Stephanopoulos, Nicholas; Alvarez, Zaida; ...

2017-07-10

The native extracellular matrix is a space in which signals can be displayed dynamically and reversibly, positioned with nanoscale precision, and combined synergistically to control cell function. Here we describe a molecular system that can be programmed to control these three characteristics. In this approach we immobilize peptide-DNA (P-DNA) molecules on a surface through complementary DNA tethers directing cells to adhere and spread reversibly over multiple cycles. The DNA can also serve as a molecular ruler to control the distance-dependent synergy between two peptides. Finally, we use two orthogonal DNA handles to regulate two different bioactive signals, with the abilitymore » to independently up- or downregulate each over time. This enabled us to discover that neural stem cells, derived from the murine spinal cord and organized as neurospheres, can be triggered to migrate out in response to an exogenous signal but then regroup into a neurosphere as the signal is removed.« less

BMP signaling is required for development of the ciliary body.

PubMed

Zhao, Shulei; Chen, Qin; Hung, Fang-Cheng; Overbeek, Paul A

2002-10-01

The ciliary body in the eye secretes aqueous humor and glycoproteins of the vitreous body and maintains the intraocular pressure. The ciliary muscle controls the shape of the lens through the ciliary zonules to focus the image onto the retina. During embryonic development, the ciliary epithelium is derived from the optic vesicle, but the molecular signals that control morphogenesis of the ciliary body are unknown. We report that lens-specific expression of a transgenic protein, Noggin, can block BMP signaling in the mouse eye and result in failure in formation of the ciliary processes. Co-expression of transgenic BMP7 restores normal development of the ciliary epithelium. Ectopic expression of Noggin also promotes differentiation of retinal ganglion cells. These results indicate that BMP signaling is required for development of the ciliary body and may also play a role in regulation of neuronal differentiation in the developing eye.

Early Life Stress Effects on Glucocorticoid—BDNF Interplay in the Hippocampus

PubMed Central

Daskalakis, Nikolaos P.; De Kloet, Edo Ronald; Yehuda, Rachel; Malaspina, Dolores; Kranz, Thorsten M.

2015-01-01

Early life stress (ELS) is implicated in the etiology of multiple psychiatric disorders. Important biological effects of ELS are manifested in stress-susceptible regions of the hippocampus and are partially mediated by long-term effects on glucocorticoid (GC) and/or neurotrophin signaling pathways. GC-signaling mediates the regulation of stress response to maintain homeostasis, while neurotrophin signaling plays a key role in neuronal outgrowth and is crucial for axonal guidance and synaptic integrity. The neurotrophin and GC-signaling pathways co-exist throughout the central nervous system (CNS), particularly in the hippocampus, which has high expression levels of glucocorticoid-receptors (GR) and mineralocorticoid-receptors (MR) as well as brain-derived neurotrophic factor (BDNF) and its receptor, tropomyosin-related kinase receptor B (TrkB). This review addresses the effects of ELS paradigms on GC- and BDNF-dependent mechanisms and their crosstalk in the hippocampus, including potential implications for the pathogenesis of common stress-related disorders. PMID:26635521

Instructing cells with programmable peptide DNA hybrids

NASA Astrophysics Data System (ADS)

Freeman, Ronit; Stephanopoulos, Nicholas; Álvarez, Zaida; Lewis, Jacob A.; Sur, Shantanu; Serrano, Chris M.; Boekhoven, Job; Lee, Sungsoo S.; Stupp, Samuel I.

2017-07-01

The native extracellular matrix is a space in which signals can be displayed dynamically and reversibly, positioned with nanoscale precision, and combined synergistically to control cell function. Here we describe a molecular system that can be programmed to control these three characteristics. In this approach we immobilize peptide-DNA (P-DNA) molecules on a surface through complementary DNA tethers directing cells to adhere and spread reversibly over multiple cycles. The DNA can also serve as a molecular ruler to control the distance-dependent synergy between two peptides. Finally, we use two orthogonal DNA handles to regulate two different bioactive signals, with the ability to independently up- or downregulate each over time. This enabled us to discover that neural stem cells, derived from the murine spinal cord and organized as neurospheres, can be triggered to migrate out in response to an exogenous signal but then regroup into a neurosphere as the signal is removed.

Long-distance transport of signals during symbiosis

PubMed Central

Xie, Zhi-Ping; Illana, Antonio

2011-01-01

Legumes enter nodule symbioses with nitrogen-fixing bacteria (rhizobia), whereas most flowering plants establish symbiotic associations with arbuscular mycorrhizal (AM) fungi. Once first steps of symbiosis are initiated, nodule formation and mycorrhization in legumes is negatively controlled by a shoot-derived inhibitor (SDI), a phenomenon termed autoregulation. According to current views, autoregulation of nodulation and mycorrhization in legumes is regulated in a similar way. CLE peptides induced in response to rhizobial nodulation signals (Nod factors) have been proposed to represent the ascending long-distance signals to the shoot. Although not proven yet, these CLE peptides are likely perceived by leucine-rich repeat (LRR) autoregulation receptor kinases in the shoot. Autoregulation of mycorrhization in non-legumes is reminiscent to the phenomenon of “systemic acquired resistance” in plant-pathogen interactions. PMID:21455020

FOXO1 orchestrates the bone-suppressing function of gut-derived serotonin

PubMed Central

Kode, Aruna; Mosialou, Ioanna; Silva, Barbara C.; Rached, Marie-Therese; Zhou, Bin; Wang, Ji; Townes, Tim M.; Hen, Rene; DePinho, Ronald A.; Guo, X. Edward; Kousteni, Stavroula

2012-01-01

Serotonin is a critical regulator of bone mass, fulfilling different functions depending on its site of synthesis. Brain-derived serotonin promotes osteoblast proliferation, whereas duodenal-derived serotonin suppresses it. To understand the molecular mechanisms of duodenal-derived serotonin action on osteoblasts, we explored its transcriptional mediation in mice. We found that the transcription factor FOXO1 is a crucial determinant of the effects of duodenum-derived serotonin on bone formation We identified two key FOXO1 complexes in osteoblasts, one with the transcription factor cAMP-responsive element–binding protein 1 (CREB) and another with activating transcription factor 4 (ATF4). Under normal levels of circulating serotonin, the proliferative activity of FOXO1 was promoted by a balance between its interaction with CREB and ATF4. However, high circulating serotonin levels prevented the association of FOXO1 with CREB, resulting in suppressed osteoblast proliferation. These observations identify FOXO1 as the molecular node of an intricate transcriptional machinery that confers the signal of duodenal-derived serotonin to inhibit bone formation. PMID:22945629

Chimeras of the native form or achondroplasia mutant (G375C) of human fibroblast growth factor receptor 3 induce ligand-dependent differentiation of PC12 cells.

PubMed Central

Thompson, L M; Raffioni, S; Wasmuth, J J; Bradshaw, R A

1997-01-01

Mutations in the gene for human fibroblast growth factor receptor 3 (hFGFR3) cause a variety of skeletal dysplasias, including the most common genetic form of dwarfism, achondroplasia (ACH). Evidence indicates that these phenotypes are not due to simple haploinsufficiency of FGFR3 but are more likely related to a role in negatively regulating skeletal growth. The effects of one of these mutations on FGFR3 signaling were examined by constructing chimeric receptors composed of the extracellular domain of human platelet-derived growth factor receptor beta (hPDGFR beta) and the transmembrane and intracellular domains of hFGFR3 or of an ACH (G375C) mutant. Following stable transfection in PC12 cells, which lack platelet-derived growth factor (PDGF) receptors, all clonal cell lines, with either type of chimera, showed strong neurite outgrowth in the presence of PDGF but not in its absence. Antiphosphotyrosine immunoblots showed ligand-dependent autophosphorylation, and both receptor types stimulated strong phosphorylation of mitogen-activated protein kinase (MAPK)/extracellular signal-regulated kinase, an event associated with the differentiative response of these cells. In addition, ligand-dependent phosphorylation of phospholipase Cgamma and Shc was also observed. All of these responses were comparable to those observed from ligand activation, such as by nerve growth factor, of the native PC12 cells used to prepare the stable transfectants. The cells with the chimera bearing the ACH mutation were more rapidly responsive to ligand with less sustained MAPK activation, indicative of a preactivated or primed condition and consistent with the view that these mutations weaken ligand control of FGFR3 function. However, the full effect of the mutation likely depends in part on structural features of the extracellular domain. Although FGFR3 has been suggested to act as a negative regulator of long-bone growth in chrondrocytes, it produces differentiative signals similar to those of FGFR1, to which only positive effects have been ascribed, in PC12 cells. Therefore, its regulatory effects on bone growth likely result from cellular contexts and not the induction of a unique FGFR3 signaling pathway. PMID:9199352

Ras-Induced Changes in H3K27me3 Occur after Those in Transcriptional Activity

PubMed Central

Hosogane, Masaki; Funayama, Ryo; Nishida, Yuichiro; Nagashima, Takeshi; Nakayama, Keiko

2013-01-01

Oncogenic signaling pathways regulate gene expression in part through epigenetic modification of chromatin including DNA methylation and histone modification. Trimethylation of histone H3 at lysine-27 (H3K27), which correlates with transcriptional repression, is regulated by an oncogenic form of the small GTPase Ras. Although accumulation of trimethylated H3K27 (H3K27me3) has been implicated in transcriptional regulation, it remains unclear whether Ras-induced changes in H3K27me3 are a trigger for or a consequence of changes in transcriptional activity. We have now examined the relation between H3K27 trimethylation and transcriptional regulation by Ras. Genome-wide analysis of H3K27me3 distribution and transcription at various times after expression of oncogenic Ras in mouse NIH 3T3 cells identified 115 genes for which H3K27me3 level at the gene body and transcription were both regulated by Ras. Similarly, 196 genes showed Ras-induced changes in transcription and H3K27me3 level in the region around the transcription start site. The Ras-induced changes in transcription occurred before those in H3K27me3 at the genome-wide level, a finding that was validated by analysis of individual genes. Depletion of H3K27me3 either before or after activation of Ras signaling did not affect the transcriptional regulation of these genes. Furthermore, given that H3K27me3 enrichment was dependent on Ras signaling, neither it nor transcriptional repression was maintained after inactivation of such signaling. Unexpectedly, we detected unannotated transcripts derived from intergenic regions at which the H3K27me3 level is regulated by Ras, with the changes in transcript abundance again preceding those in H3K27me3. Our results thus indicate that changes in H3K27me3 level in the gene body or in the region around the transcription start site are not a trigger for, but rather a consequence of, changes in transcriptional activity. PMID:24009517

Impaired coordination between signaling pathways is revealed in human colorectal cancer using single-cell mass cytometry of archival tissue blocks

PubMed Central

Simmons, Alan J.; Scurrah, Cherie’ R.; McKinley, Eliot T.; Herring, Charles A.; Irish, Jonathan M.; Washington, Mary K.; Coffey, Robert J.; Lau, Ken S.

2016-01-01

Cellular heterogeneity poses a significant challenge to understanding tissue level phenotypes and confounds conventional bulk analyses. To facilitate the analysis of signaling at the single-cell level in human tissues, we applied mass cytometry using CyTOF (Cytometry Time-of-Flight) to formalin-fixed paraffin-embedded (FFPE) normal and diseased intestinal specimens. We developed and validated a technique called FFPE-DISSECT (Disaggregation for Intracellular Signaling in Single Epithelial Cells from Tissue), a single-cell approach for characterizing native signaling states from embedded solid tissue samples. We applied FFPE-DISSECT coupled to mass cytometry and found differential signaling by tumor necrosis factor α (TNF-α) in intestinal enterocytes, goblet cells and enteroendocrine cells, implicating the role of the downstream RAS-RAF-MEK-ERK signaling pathway in dictating goblet cell identity. In addition, application of FFPE-DISSECT, mass cytometry, and data-driven computational analyses to human colon specimens confirmed reduced differentiation in colorectal cancer (CRC) compared to normal colon, and revealed quantitative increases in inter- and intra-tissue heterogeneity in CRC with regards to the modular regulation of signaling pathways. Specifically, modular co-regulation of the kinases P38 and ERK, the translation regulator 4EBP1, and the transcription factor CREB in the proliferative compartment of the normal colon was loss in CRC, as evidenced by their impaired coordination over samplings of single cells in tissue. Our data suggest that this single-cell approach, applied in conjunction with genomic annotation, such as microsatellite instability and mutations in KRAS and BRAF, allows rapid and detailed characterization of cellular heterogeneity from clinical repositories of embedded human tissues. FFPE-DISSECT coupled of mass cytometry can be used for deriving cellular landscapes from archived patient samples, beyond CRC, and as a high resolution tool for disease characterization and subtyping. PMID:27729552

A proangiogenic signaling axis in myeloid cells promotes malignant progression of glioma.

PubMed

Huang, Yujie; Rajappa, Prajwal; Hu, Wenhuo; Hoffman, Caitlin; Cisse, Babacar; Kim, Joon-Hyung; Gorge, Emilie; Yanowitch, Rachel; Cope, William; Vartanian, Emma; Xu, Raymond; Zhang, Tuo; Pisapia, David; Xiang, Jenny; Huse, Jason; Matei, Irina; Peinado, Hector; Bromberg, Jacqueline; Holland, Eric; Ding, Bi-Sen; Rafii, Shahin; Lyden, David; Greenfield, Jeffrey

2017-05-01

Tumors are capable of coopting hematopoietic cells to create a suitable microenvironment to support malignant growth. Here, we have demonstrated that upregulation of kinase insert domain receptor (KDR), also known as VEGFR2, in a myeloid cell sublineage is necessary for malignant progression of gliomas in transgenic murine models and is associated with high-grade tumors in patients. KDR expression increased in myeloid cells as myeloid-derived suppressor cells (MDSCs) accumulated, which was associated with the transformation and progression of low-grade fibrillary astrocytoma to high-grade anaplastic gliomas. KDR deficiency in murine BM-derived cells (BMDCs) suppressed the differentiation of myeloid lineages and reduced granulocytic/monocytic populations. The depletion of myeloid-derived KDR compromised its proangiogenic function, which inhibited the angiogenic switch necessary for malignant progression of low-grade to high-grade tumors. We also identified inhibitor of DNA binding protein 2 (ID2) as a key upstream regulator of KDR activation during myeloid differentiation. Deficiency of ID2 in BMDCs led to downregulation of KDR, suppression of proangiogenic myeloid cells, and prevention of low-grade to high-grade transition. Tumor-secreted TGF-β and granulocyte-macrophage CSF (GM-CSF) enhanced the KDR/ID2 signaling axis in BMDCs. Our results suggest that modulation of KDR/ID2 signaling may restrict tumor-associated myeloid cells and could potentially be a therapeutic strategy for preventing transformation of premalignant gliomas.

A proangiogenic signaling axis in myeloid cells promotes malignant progression of glioma

PubMed Central

Huang, Yujie; Rajappa, Prajwal; Hu, Wenhuo; Hoffman, Caitlin; Cisse, Babacar; Kim, Joon-Hyung; Gorge, Emilie; Yanowitch, Rachel; Cope, William; Vartanian, Emma; Xu, Raymond; Pisapia, David; Xiang, Jenny; Huse, Jason; Matei, Irina; Peinado, Hector; Bromberg, Jacqueline; Holland, Eric; Ding, Bi-sen; Rafii, Shahin; Lyden, David; Greenfield, Jeffrey

2017-01-01

Tumors are capable of coopting hematopoietic cells to create a suitable microenvironment to support malignant growth. Here, we have demonstrated that upregulation of kinase insert domain receptor (KDR), also known as VEGFR2, in a myeloid cell sublineage is necessary for malignant progression of gliomas in transgenic murine models and is associated with high-grade tumors in patients. KDR expression increased in myeloid cells as myeloid-derived suppressor cells (MDSCs) accumulated, which was associated with the transformation and progression of low-grade fibrillary astrocytoma to high-grade anaplastic gliomas. KDR deficiency in murine BM-derived cells (BMDCs) suppressed the differentiation of myeloid lineages and reduced granulocytic/monocytic populations. The depletion of myeloid-derived KDR compromised its proangiogenic function, which inhibited the angiogenic switch necessary for malignant progression of low-grade to high-grade tumors. We also identified inhibitor of DNA binding protein 2 (ID2) as a key upstream regulator of KDR activation during myeloid differentiation. Deficiency of ID2 in BMDCs led to downregulation of KDR, suppression of proangiogenic myeloid cells, and prevention of low-grade to high-grade transition. Tumor-secreted TGF-β and granulocyte-macrophage CSF (GM-CSF) enhanced the KDR/ID2 signaling axis in BMDCs. Our results suggest that modulation of KDR/ID2 signaling may restrict tumor-associated myeloid cells and could potentially be a therapeutic strategy for preventing transformation of premalignant gliomas. PMID:28394259

Bid Promotes K63-Linked Polyubiquitination of Tumor Necrosis Factor Receptor Associated Factor 6 (TRAF6) and Sensitizes to Mutant SOD1-Induced Proinflammatory Signaling in Microglia.

PubMed

Kinsella, Sinéad; König, Hans-Georg; Prehn, Jochen H M

2016-01-01

Mutations in the superoxide dismutase 1 (SOD1) gene contribute to motoneuron degeneration and are evident in 20% of familial amyotrophic lateral sclerosis cases. Mutant SOD1 induces microglial activation through a stimulation of Toll-like receptors 2 and 4 (TLR2 and TLR4). In the present study, we identified the proapoptotic Bcl-2 family protein Bid as a positive regulator of mutant SOD1-induced TLR-nuclear factor-κB (NF-κB) signaling in microglia. bid-deficient primary mouse microglia showed reduced NF-κB signaling in response to TLR4 activation or exposure to conditioned medium derived from SOD1 (G93A) expressing NSC-34 cells. Attenuation of NF-κB signaling in bid-deficient microglia was associated with lower levels of phosphorylated IKKα/β and p65, with a delayed degradation of IκBα and enhanced degradation of Peli1. Upstream of IKK, we found that Bid interacted with, and promoted, the K63-linked polyubiquitination of the E3 ubiquitin ligase tumor necrosis factor receptor associated factor 6 (TRAF6) in microglia. Our study suggests a key role for Bid in the regulation of TLR4-NF-κB proinflammatory signaling during mutant SOD1-induced disease pathology. Bid promotes TLR4-NF-κB signaling by interacting with TRAF6 and promoting TRAF6 K63-linked polyubiquitination in microglia.

Bid Promotes K63-Linked Polyubiquitination of Tumor Necrosis Factor Receptor Associated Factor 6 (TRAF6) and Sensitizes to Mutant SOD1-Induced Proinflammatory Signaling in Microglia123

PubMed Central

Kinsella, Sinéad

2016-01-01

Mutations in the superoxide dismutase 1 (SOD1) gene contribute to motoneuron degeneration and are evident in 20% of familial amyotrophic lateral sclerosis cases. Mutant SOD1 induces microglial activation through a stimulation of Toll-like receptors 2 and 4 (TLR2 and TLR4). In the present study, we identified the proapoptotic Bcl-2 family protein Bid as a positive regulator of mutant SOD1-induced TLR-nuclear factor-κB (NF-κB) signaling in microglia. bid-deficient primary mouse microglia showed reduced NF-κB signaling in response to TLR4 activation or exposure to conditioned medium derived from SOD1 G93A expressing NSC-34 cells. Attenuation of NF-κB signaling in bid-deficient microglia was associated with lower levels of phosphorylated IKKα/β and p65, with a delayed degradation of IκBα and enhanced degradation of Peli1. Upstream of IKK, we found that Bid interacted with, and promoted, the K63-linked polyubiquitination of the E3 ubiquitin ligase tumor necrosis factor receptor associated factor 6 (TRAF6) in microglia. Our study suggests a key role for Bid in the regulation of TLR4-NF-κB proinflammatory signaling during mutant SOD1-induced disease pathology. Bid promotes TLR4-NF-κB signaling by interacting with TRAF6 and promoting TRAF6 K63-linked polyubiquitination in microglia. PMID:27257617

Long noncoding RNA derived from CD244 signaling epigenetically controls CD8+ T-cell immune responses in tuberculosis infection

PubMed Central

Wang, Yang; Zhong, Huiling; Xie, Xiaodan; Chen, Crystal Y.; Huang, Dan; Shen, Ling; Zhang, Hui; Chen, Zheng W.; Zeng, Gucheng

2015-01-01

Molecular mechanisms for T-cell immune responses modulated by T cell-inhibitory molecules during tuberculosis (TB) infection remain unclear. Here, we show that active human TB infection up-regulates CD244 and CD244 signaling-associated molecules in CD8+ T cells and that blockade of CD244 signaling enhances production of IFN-γ and TNF-α. CD244 expression/signaling in TB correlates with high levels of a long noncoding RNA (lncRNA)-BC050410 [named as lncRNA-AS-GSTT1(1-72) or lncRNA-CD244] in the CD244+CD8+ T-cell subpopulation. CD244 signaling drives lncRNA-CD244 expression via sustaining a permissive chromatin state in the lncRNA-CD244 locus. By recruiting polycomb protein enhancer of zeste homolog 2 (EZH2) to infg/tnfa promoters, lncRNA-CD244 mediates H3K27 trimethylation at infg/tnfa loci toward repressive chromatin states and inhibits IFN-γ/TNF-α expression in CD8+ T cells. Such inhibition can be reversed by knock down of lncRNA-CD244. Interestingly, adoptive transfer of lncRNA-CD244–depressed CD8+ T cells to Mycobacterium tuberculosis (MTB)-infected mice reduced MTB infection and TB pathology compared with lncRNA-CD244–expressed controls. Thus, this work uncovers previously unidentified mechanisms in which T cell-inhibitory signaling and lncRNAs regulate T-cell responses and host defense against TB infection. PMID:26150504

BMP6 down-regulates GDNF expression through SMAD1/5 and ERK1/2 signaling pathways in human granulosa-lutein cells.

PubMed

Zhang, Xin-Yue; Chang, Hsun-Ming; Taylor, Elizabeth L; Leung, Peter C K; Liu, Rui-Zhi

2018-05-09

Bone morphogenetic protein 6 (BMP6) is a critical regulator of follicular development that is expressed in mammalian oocytes and granulosa cells. Glial cell line-derived neurotrophic factor (GDNF) is an intraovarian neurotrophic factor that plays an essential role in regulating mammalian oocyte maturation. The aim of this study was to investigate the effect of BMP6 on the regulation of GDNF expression and the potential underlying mechanisms. We used an established immortalized human granulosa cell line (SVOG cells) and primary human granulosa-lutein cells as in vitro cell models. Our results showed that BMP6 significantly down-regulated the expression of GDNF in both SVOG and primary human granulosa-lutein cells. Using dual inhibition approaches (kinase receptor inhibitor and small interfering RNA knockdown), our results showed that both ALK2 and ALK3 are involved in BMP6-induced down-regulation of GDNF. In addition, BMP6 induced the phosphorylation of SMAD1/5/8 and ERK1/2 but not AKT or p38. Among three downstream mediators, both SMAD1 and SMAD5 are involved in BMP6-induced down-regulation of GDNF. Moreover, concomitant knockdown of endogenous SMAD4 and inhibition of ERK1/2 activity completely reversed BMP6-induced down-regulation of GDNF, indicating that both SMAD and ERK1/2 signaling pathways are required for the regulatory effect of BMP6 on GDNF expression. Our findings suggest an additional role for an intrafollicular growth factor in regulating follicular function through their paracrine interactions in human granulosa cells.

Disrupting astrocyte-neuron lactate transfer persistently reduces conditioned responses to cocaine.

PubMed

Boury-Jamot, B; Carrard, A; Martin, J L; Halfon, O; Magistretti, P J; Boutrel, B

2016-08-01

A central problem in the treatment of drug addiction is the high risk of relapse often precipitated by drug-associated cues. The transfer of glycogen-derived lactate from astrocytes to neurons is required for long-term memory. Whereas blockade of drug memory reconsolidation represents a potential therapeutic strategy, the role of astrocyte-neuron lactate transport in long-term conditioning has received little attention. By infusing an inhibitor of glycogen phosphorylase into the basolateral amygdala of rats, we report that disruption of astrocyte-derived lactate not only transiently impaired the acquisition of a cocaine-induced conditioned place preference but also persistently disrupted an established conditioning. The drug memory was rescued by L-Lactate co-administration through a mechanism requiring the synaptic plasticity-related transcription factor Zif268 and extracellular signal-regulated kinase (ERK) signalling pathway but not the brain-derived neurotrophic factor (Bdnf). The long-term amnesia induced by glycogenolysis inhibition and the concomitant decreased expression of phospho-ERK were both restored with L-Lactate co-administration. These findings reveal a critical role for astrocyte-derived lactate in positive memory formation and highlight a novel amygdala-dependent reconsolidation process, whose disruption may offer a novel therapeutic target to reduce the long-lasting conditioned responses to cocaine.

Caveolae: a regulatory platform for nutritional modulation of inflammatory diseases

PubMed Central

Layne, Joseph; Majkova, Zuzana; Smart, Eric J.; Toborek, Michal; Hennig, Bernhard

2010-01-01

Dietary intervention strategies have proven to be an effective means of decreasing several risk factors associated with the development of atherosclerosis. Endothelial cell dysfunction influences vascular inflammation and is involved in promoting the earliest stages of lesion formation. Caveolae are lipid raft microdomains abundant within the plasma membrane of endothelial cells and are responsible for mediating receptor-mediated signal transduction. Caveolae have been implicated in the regulation of enzymes associated with several key signaling pathways capable of determining intracellular redox status. Diet and plasma-derived nutrients may modulate an inflammatory outcome by interacting with and altering caveolae-associated cellular signaling. For example, omega-3 fatty acids and several polyphenolics have been shown to improve endothelial cell function by decreasing the formation of ROS and increasing NO bioavailability, events associated with altered caveolae composition. Thus, nutritional modulation of caveolae-mediated signaling events may provide an opportunity to ameliorate inflammatory signaling pathways capable of promoting the formation of vascular diseases, including atherosclerosis. PMID:21292468

Jasmonate signaling in plant stress responses and development - active and inactive compounds.

PubMed

Wasternack, Claus; Strnad, Miroslav

2016-09-25

Jasmonates (JAs) are lipid-derived signals mediating plant responses to biotic and abiotic stresses and in plant development. Following the elucidation of each step in their biosynthesis and the important components of perception and signaling, several activators, repressors and co-repressors have been identified which contribute to fine-tuning the regulation of JA-induced gene expression. Many of the metabolic reactions in which JA participates, such as conjugation with amino acids, glucosylation, hydroxylation, carboxylation, sulfation and methylation, lead to numerous compounds with different biological activities. These metabolites may be highly active, partially active in specific processes or inactive. Hydroxylation, carboxylation and sulfation inactivate JA signaling. The precursor of JA biosynthesis, 12-oxo-phytodienoic acid (OPDA), has been identified as a JA-independent signaling compound. An increasing number of OPDA-specific processes is being identified. To conclude, the numerous JA compounds and their different modes of action allow plants to respond specifically and flexibly to alterations in the environment. Copyright © 2015 Elsevier B.V. All rights reserved.

Nkx2.5 regulates Endothelin Converting Enzyme-1 during pharyngeal arch patterning

PubMed Central

Iklé, Jennifer M.; Tavares, Andre L. P.; King, Marisol; Ding, Hailei; Colombo, Sophie; Firulli, Beth A.; Firulli, Anthony B.; Targoff, Kimara L.; Yelon, Deborah; Clouthier, David E.

2017-01-01

In gnathostomes, dorsoventral (D-V) patterning of neural crest cells (NCC) within the pharyngeal arches is crucial for the development of hinged jaws. One of the key signals that mediates this process is Endothelin-1 (EDN1). Loss of EDN1 binding to the Endothelin-A receptor (EDNRA) results in loss of EDNRA signaling and subsequent facial birth defects in humans, mice and zebrafish. A rate-limiting step in this crucial signaling pathway is the conversion of immature EDN1 into a mature active form by Endothelin converting enzyme-1 (ECE1). However, surprisingly little is known about how Ece1 transcription is induced or regulated. We show here that Nkx2.5 is required for proper craniofacial development in zebrafish and acts in part by upregulating ece1 expression. Disruption of nkx2.5 in zebrafish embryos results in defects in both ventral and dorsal pharyngeal arch-derived elements, with changes in ventral arch gene expression consistent with a disruption in Ednra signaling. ece1 mRNA rescues the nkx2.5 morphant phenotype, indicating that Nkx2.5 functions through modulating Ece1 expression or function. These studies illustrate a new function for Nkx2.5 in embryonic development and provide new avenues with which to pursue potential mechanisms underlying human facial disorders. PMID:28109039

Estrogen promotes megakaryocyte polyploidization via estrogen receptor beta-mediated transcription of GATA1.

PubMed

Du, C; Xu, Y; Yang, K; Chen, S; Wang, X; Wang, S; Wang, C; Shen, M; Chen, F; Chen, M; Zeng, D; Li, F; Wang, T; Wang, F; Zhao, J; Ai, G; Cheng, T; Su, Y; Wang, J

2017-04-01

Estrogen is reported to be involved in thrombopoiesis and the disruption of its signaling may cause myeloproliferative disease, yet the underlying mechanisms remain largely unknown. GATA-binding factor 1 (GATA1) is a key regulator of megakaryocyte (MK) differentiation and its deficiency will lead to megakaryoblastic leukemia. Here we show that estrogen can dose-dependently promote MK polyploidization and maturation via activation of estrogen receptor beta (ERβ), accompanied by a significant upregulation of GATA1. Chromatin immunoprecipitation and a dual luciferase assay demonstrate that ERβ can directly bind the promoter region of GATA1 and activate its transcription. Steroid receptor coactivator 3 (SRC3) is involved in ERβ-mediated GATA1 transcription. The deficiency of ERβ or SRC3, similar to the inhibition of GATA1, leads to the impediment of estrogen-induced MK polyploidization and platelet production. Further investigations reveal that signal transducer and activator of transcription 1 signaling pathway downstream of GATA1 has a crucial role in estrogen-induced MK polyploidization, and ERβ-mediated GATA1 upregulation subsequently enhances nuclear factor erythroid-derived 2 expression, thereby promoting proplatelet formation and platelet release. Our study provides a deep insight into the molecular mechanisms of estrogen signaling in regulating thrombopoiesis and the pathogenesis of ER deficiency-related leukemia.

Ascophyllan Purified from Ascophyllum nodosum Induces Th1 and Tc1 Immune Responses by Promoting Dendritic Cell Maturation

PubMed Central

Zhang, Wei; Du, Jiang-Yuan; Jiang, Zedong; Okimura, Takasi; Oda, Tatsuya; Yu, Qing; Jin, Jun-O

2014-01-01

Marine-derived sulfated polysaccharides have been shown to possess certain anti-virus, anti-tumor, anti-inflammatory and anti-coagulant activities. However, the in vivo immunomodulatory effects of marine-derived pure compounds have been less well characterized. In this study, we investigated the effect of ascophyllan, a sulfated polysaccharide purified from Ascophyllum nodosum, on the maturation of mouse dendritic cells (DCs) in vitro and in vivo. Ascophyllan induced up-regulation of co-stimulatory molecules and production of pro-inflammatory cytokines in bone marrow-derived DCs (BMDCs). Moreover, in vivo administration of ascophyllan promotes up-regulation of CD40, CD80, CD86, MHC class I and MHC class II and production of IL-6, IL-12 and TNF-α in spleen cDCs. Interestingly, ascophyllan induced a higher degree of co-stimulatory molecule up-regulation and pro-inflammatory cytokine production than fucoidan, a marine-derived polysaccharide with well-defined effect for promoting DC maturation. Ascophyllan also promoted the generation of IFN-γ-producing Th1 and Tc1 cells in the presence of DCs in an IL-12-dependent manner. Finally, myeloid differentiation primary response 88 (MyD88) signaling pathway was essential for DC maturation induced by ascophyllan. Taken together, these results demonstrate that ascophyllan induces DC maturation, and consequently enhances Th1 and Tc1 responses in vivo. This knowledge could facilitate the development of novel therapeutic strategies to combat infectious diseases and cancer. PMID:25026264

Disruption of c-Kit Signaling in Kit(W-sh/W-sh) Growing Mice Increases Bone Turnover.

PubMed

Lotinun, Sutada; Krishnamra, Nateetip

2016-08-16

c-Kit tyrosine kinase receptor has been identified as a regulator of bone homeostasis. The c-Kit loss-of-function mutations in WBB6F1/J-Kit(W/W-v) mice result in low bone mass. However, these mice are sterile and it is unclear whether the observed skeletal phenotype is secondary to a sex hormone deficiency. In contrast, C57BL/6J-Kit(W-sh)/(W-sh) (W(sh)/W(sh)) mice, which carry an inversion mutation affecting the transcriptional regulatory elements of the c-Kit gene, are fertile. Here, we showed that W(sh)/W(sh) mice exhibited osteopenia with elevated bone resorption and bone formation at 6- and 9-week-old. The c-Kit W(sh) mutation increased osteoclast differentiation, the number of committed osteoprogenitors, alkaline phosphatase activity and mineralization. c-Kit was expressed in both osteoclasts and osteoblasts, and c-Kit expression was decreased in W(sh)/W(sh)osteoclasts, but not osteoblasts, suggesting an indirect effect of c-Kit on bone formation. Furthermore, the osteoclast-derived coupling factor Wnt10b mRNA was increased in W(sh)/W(sh) osteoclasts. Conditioned medium from W(sh)/W(sh) osteoclasts had elevated Wnt10b protein levels and induced increased alkaline phosphatase activity and mineralization in osteoblast cultures. Antagonizing Wnt10b signaling with DKK1 or Wnt10b antibody inhibited these effects. Our data suggest that c-Kit negatively regulates bone turnover, and disrupted c-Kit signaling couples increased bone resorption with bone formation through osteoclast-derived Wnt 10 b.

Plant-derived flavone Apigenin: The small-molecule with promising activity against therapeutically resistant prostate cancer.

PubMed

Ganai, Shabir Ahmad

2017-01-01

Prostate cancer is the second leading cause of cancer related deaths in men in the United States. Mounting evidences suggest that in the pathophysiology of prostate cancer epigenetic modifications play a considerable role. Histone deacetylases (HDACs) have strong crosstalk with prostate cancer progression as they regulate various genes meant for tumour suppression. HDACs are emerging as striking molecular targets for anticancer drugs and therapy as their aberrant expression has been implicated in several cancers. Histone deacetylase inhibitors (HDACi), the small molecules interfering HDACs are the propitious chemotherapeutic agents as they tune the altered acetylation homeostasis for attenuating disease signalling. More than 20 HDACi have entered into the clinical trials and 4 have crossed the journey by gaining FDA approval for treating distinct haematological malignancies including multiple myeloma. Despite the therapeutic benefits, the synthetic HDACi cause detrimental side effects like atrial fibrillation, raising concerns regarding their applicability. Taking these facts into consideration the current article focused on plant-derived HDAC inhibitor Apigenin and its marvelous role in prostate cancer therapy. Moreover, the article sheds light on Apigenin induced apoptosis in various prostate cancer models. The defined inhibitor provokes apoptotic signaling in these models by multiple mechanisms like restraining HDACs, declining the levels of antiapoptotic proteins. Importantly, Apigenin hampers NF-κB signalling and down-modulates its regulated gene products for bringing therapeutic effect. Furthermore, Apigenin shows synergistic effect in combinatorial therapy and induces apoptosis even in prostate cancer models resistant to conventional therapeutic regimens. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

Aberrant Ras regulation and reduced p190 tyrosine phosphorylation in cells lacking p120-Gap.

PubMed Central

van der Geer, P; Henkemeyer, M; Jacks, T; Pawson, T

1997-01-01

The Ras guanine nucleotide-binding protein functions as a molecular switch in signalling downstream of protein-tyrosine kinases. Ras is activated by exchange of GDP for GTP and is turned off by hydrolysis of bound GTP to GDP. Ras itself has a low intrinsic GTPase activity that can be stimulated by GTPase-activating proteins (GAPs), including p120-Gap and neurofibromin. These GAPs possess a common catalytic domain but contain distinct regulatory elements that may couple different external signals to control of the Ras pathway. p120-Gap, for example, has two N-terminal SH2 domains that directly recognize phosphotyrosine motifs on activated growth factor receptors and cytoplasmic phosphoproteins. To analyze the role of p120-Gap in Ras regulation in vivo, we have used fibroblasts derived from mouse embryos with a null mutation in the gene for p120-Gap (Gap). Platelet-derived growth factor stimulation of Gap-/- cells led to an abnormally large increase in the level of Ras-GTP and in the duration of mitogen-activated protein (MAP) kinase activation compared with wild-type cells, suggesting that p120-Gap is specifically activated following growth factor stimulation. Induction of DNA synthesis in response to platelet-derived growth factor and morphological transformation by the v-src and EJ-ras oncogenes were not significantly affected by the absence of p120-Gap. However, we found that normal tyrosine phosphorylation of p190-rhoGap, a cytoplasmic protein that associates with the p120-Gap SH2 domains, was dependent on the presence of p120-Gap. Our results suggest that p120-Gap has specific functions in downregulating the Ras/MAP kinase pathway following growth factor stimulation, and in modulating the phosphorylation of p190-rhoGap, but is not required for mitogenic signalling. PMID:9121432

Human Mas-Related G Protein-Coupled Receptors-X1 Induce Chemokine Receptor 2 Expression in Rat Dorsal Root Ganglia Neurons and Release of Chemokine Ligand 2 from the Human LAD-2 Mast Cell Line

PubMed Central

Solinski, Hans Jürgen; Petermann, Franziska; Rothe, Kathrin; Boekhoff, Ingrid; Gudermann, Thomas; Breit, Andreas

2013-01-01

Primate-specific Mas-related G protein-coupled receptors-X1 (MRGPR-X1) are highly enriched in dorsal root ganglia (DRG) neurons and induce acute pain. Herein, we analyzed effects of MRGPR-X1 on serum response factors (SRF) or nuclear factors of activated T cells (NFAT), which control expression of various markers of chronic pain. Using HEK293, DRG neuron-derived F11 cells and cultured rat DRG neurons recombinantly expressing human MRGPR-X1, we found activation of a SRF reporter gene construct and induction of the early growth response protein-1 via extracellular signal-regulated kinases-1/2 known to play a significant role in the development of inflammatory pain. Furthermore, we observed MRGPR-X1-induced up-regulation of the chemokine receptor 2 (CCR2) via NFAT, which is considered as a key event in the onset of neuropathic pain and, so far, has not yet been described for any endogenous neuropeptide. Up-regulation of CCR2 is often associated with increased release of its endogenous agonist chemokine ligand 2 (CCL2). We also found MRGPR-X1-promoted release of CCL2 in a human connective tissue mast cell line endogenously expressing MRGPR-X1. Thus, we provide first evidence to suggest that MRGPR-X1 induce expression of chronic pain markers in DRG neurons and propose a so far unidentified signaling circuit that enhances chemokine signaling by acting on two distinct yet functionally co-operating cell types. Given the important role of chemokine signaling in pain chronification, we propose that interruption of this signaling circuit might be a promising new strategy to alleviate chemokine-promoted pain. PMID:23505557

Proliferation of murine midbrain neural stem cells depends upon an endogenous sonic hedgehog (Shh) source.

PubMed

Martínez, Constanza; Cornejo, Víctor Hugo; Lois, Pablo; Ellis, Tammy; Solis, Natalia P; Wainwright, Brandon J; Palma, Verónica

2013-01-01

The Sonic Hedgehog (Shh) pathway is responsible for critical patterning events early in development and for regulating the delicate balance between proliferation and differentiation in the developing and adult vertebrate brain. Currently, our knowledge of the potential role of Shh in regulating neural stem cells (NSC) is largely derived from analyses of the mammalian forebrain, but for dorsal midbrain development it is mostly unknown. For a detailed understanding of the role of Shh pathway for midbrain development in vivo, we took advantage of mouse embryos with cell autonomously activated Hedgehog (Hh) signaling in a conditional Patched 1 (Ptc1) mutant mouse model. This animal model shows an extensive embryonic tectal hypertrophy as a result of Hh pathway activation. In order to reveal the cellular and molecular origin of this in vivo phenotype, we established a novel culture system to evaluate neurospheres (nsps) viability, proliferation and differentiation. By recreating the three-dimensional (3-D) microenvironment we highlight the pivotal role of endogenous Shh in maintaining the stem cell potential of tectal radial glial cells (RGC) and progenitors by modulating their Ptc1 expression. We demonstrate that during late embryogenesis Shh enhances proliferation of NSC, whereas blockage of endogenous Shh signaling using cyclopamine, a potent Hh pathway inhibitor, produces the opposite effect. We propose that canonical Shh signaling plays a central role in the control of NSC behavior in the developing dorsal midbrain by acting as a niche factor by partially mediating the response of NSC to epidermal growth factor (EGF) and fibroblast growth factor (FGF) signaling. We conclude that endogenous Shh signaling is a critical mechanism regulating the proliferation of stem cell lineages in the embryonic dorsal tissue.

Genetic reductionist approach for dissecting individual roles of GGDEF proteins within the c-di-GMP signaling network in Salmonella

PubMed Central

Solano, Cristina; García, Begoña; Latasa, Cristina; Toledo-Arana, Alejandro; Zorraquino, Violeta; Valle, Jaione; Casals, Joan; Pedroso, Enrique; Lasa, Iñigo

2009-01-01

Bacteria have developed an exclusive signal transduction system involving multiple diguanylate cyclase and phosphodiesterase domain-containing proteins (GGDEF and EAL/HD-GYP, respectively) that modulate the levels of the same diffusible molecule, 3′-5′-cyclic diguanylic acid (c-di-GMP), to transmit signals and obtain specific cellular responses. Current knowledge about c-di-GMP signaling has been inferred mainly from the analysis of recombinant bacteria that either lack or overproduce individual members of the pathway, without addressing potential compensatory effects or interferences between them. Here, we dissected c-di-GMP signaling by constructing a Salmonella strain lacking all GGDEF-domain proteins and then producing derivatives, each restoring 1 protein. Our analysis showed that most GGDEF proteins are constitutively expressed and that their expression levels are not interdependent. Complete deletion of genes encoding GGDEF-domain proteins abrogated virulence, motility, long-term survival, and cellulose and fimbriae synthesis. Separate restoration revealed that 4 proteins from Salmonella and 1 from Yersinia pestis exclusively restored cellulose synthesis in a c-di-GMP–dependent manner, indicating that c-di-GMP produced by different GGDEF proteins can activate the same target. However, the restored strain containing the STM4551-encoding gene recovered all other phenotypes by means of gene expression modulation independently of c-di-GMP. Specifically, fimbriae synthesis and virulence were recovered through regulation of csgD and the plasmid-encoded spvAB mRNA levels, respectively. This study provides evidence that the regulation of the GGDEF-domain proteins network occurs at 2 levels: a level that strictly requires c-di-GMP to control enzymatic activities directly, restricted to cellulose synthesis in our experimental conditions, and another that involves gene regulation for which c-di-GMP synthesis can be dispensable. PMID:19416883

Distinctive effects of eicosapentaenoic and docosahexaenoic acids in regulating neural stem cell fate are mediated via endocannabinoid signalling pathways.

PubMed

Dyall, S C; Mandhair, H K; Fincham, R E A; Kerr, D M; Roche, M; Molina-Holgado, F

2016-08-01

Emerging evidence suggests a complex interplay between the endocannabinoid system, omega-3 fatty acids and the immune system in the promotion of brain self-repair. However, it is unknown if all omega-3 fatty acids elicit similar effects on adult neurogenesis and if such effects are mediated or regulated by interactions with the endocannabinoid system. This study investigated the effects of DHA and EPA on neural stem cell (NSC) fate and the role of the endocannabinoid signalling pathways in these effects. EPA, but not DHA, significantly increased proliferation of NSCs compared to controls, an effect associated with enhanced levels of the endocannabinoid 2-arachidonylglycerol (2-AG) and p-p38 MAPK, effects attenuated by pre-treatment with CB1 (AM251) or CB2 (AM630) receptor antagonists. Furthermore, in NSCs derived from IL-1β deficient mice, EPA significantly decreased proliferation and p-p38 MAPK levels compared to controls, suggesting a key role for IL-1β signalling in the effects observed. Although DHA similarly increased 2-AG levels in wild-type NSCs, there was no concomitant increase in proliferation or p-p38 MAPK activity. In addition, in NSCs from IL-1β deficient mice, DHA significantly increased proliferation without effects on p-P38 MAPK, suggesting effects of DHA are mediated via alternative signalling pathways. These results provide crucial new insights into the divergent effects of EPA and DHA in regulating NSC proliferation and the pathways involved, and highlight the therapeutic potential of their interplay with endocannabinoid signalling in brain repair. Copyright © 2016 Elsevier Ltd. All rights reserved.

High-throughput screening of tyrosine kinase inhibitor cardiotoxicity with human induced pluripotent stem cells.

PubMed

Sharma, Arun; Burridge, Paul W; McKeithan, Wesley L; Serrano, Ricardo; Shukla, Praveen; Sayed, Nazish; Churko, Jared M; Kitani, Tomoya; Wu, Haodi; Holmström, Alexandra; Matsa, Elena; Zhang, Yuan; Kumar, Anusha; Fan, Alice C; Del Álamo, Juan C; Wu, Sean M; Moslehi, Javid J; Mercola, Mark; Wu, Joseph C

2017-02-15

Tyrosine kinase inhibitors (TKIs), despite their efficacy as anticancer therapeutics, are associated with cardiovascular side effects ranging from induced arrhythmias to heart failure. We used human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs), generated from 11 healthy individuals and 2 patients receiving cancer treatment, to screen U.S. Food and Drug Administration-approved TKIs for cardiotoxicities by measuring alterations in cardiomyocyte viability, contractility, electrophysiology, calcium handling, and signaling. With these data, we generated a "cardiac safety index" to reflect the cardiotoxicities of existing TKIs. TKIs with low cardiac safety indices exhibit cardiotoxicity in patients. We also derived endothelial cells (hiPSC-ECs) and cardiac fibroblasts (hiPSC-CFs) to examine cell type-specific cardiotoxicities. Using high-throughput screening, we determined that vascular endothelial growth factor receptor 2 (VEGFR2)/platelet-derived growth factor receptor (PDGFR)-inhibiting TKIs caused cardiotoxicity in hiPSC-CMs, hiPSC-ECs, and hiPSC-CFs. With phosphoprotein analysis, we determined that VEGFR2/PDGFR-inhibiting TKIs led to a compensatory increase in cardioprotective insulin and insulin-like growth factor (IGF) signaling in hiPSC-CMs. Up-regulating cardioprotective signaling with exogenous insulin or IGF1 improved hiPSC-CM viability during cotreatment with cardiotoxic VEGFR2/PDGFR-inhibiting TKIs. Thus, hiPSC-CMs can be used to screen for cardiovascular toxicities associated with anticancer TKIs, and the results correlate with clinical phenotypes. This approach provides unexpected insights, as illustrated by our finding that toxicity can be alleviated via cardioprotective insulin/IGF signaling. Copyright © 2017, American Association for the Advancement of Science.

Adipocyte-derived Exosomal miRNAs: A Novel Mechanism for Obesity-Related Disease

PubMed Central

Ferrante, Sarah C; Nadler, Evan P; Pillai, Dinesh K; Hubal, Monica J; Wang, Zuyi; Wang, Justin M; Gordish-Dressman, Heather; Koeck, Emily; Sevilla, Samantha; Wiles, Andrew A; Freishtat, Robert J

2014-01-01

Background Obesity is frequently complicated by comorbid conditions, yet how excess adipose contributes is poorly understood. Although adipocytes in obese individuals induce systemic inflammation via secreted cytokines, another potential mediator has recently been identified (i.e. adipocyte-derived exosomes). We hypothesized that adipocyte-derived exosomes contain mediators capable of activating end-organ inflammatory and fibrotic signaling pathways. Methods We developed techniques to quantify and characterize exosomes shed by adipocytes from 7 obese (age: 12–17.5 years, BMI: 33–50 kg/m2) and 5 lean (age: 11–19 years, BMI: 22–25 kg/m2) subjects. Results Abundant exosomal miRNAs, but no mRNAs, were detected. Comparison of obese vs. lean visceral adipose donors detected 55 differentially-expressed miRNAs (p<0.05; fold change≥|1.2|). qRT-PCR confirmed downregulation of miR-148b (ratio = 0.2 [95% confidence interval = 0.1, 0.6]) and miR-4269 (0.3 [0.1, 0.8]), and upregulation of miR-23b (6.2 [2.2, 17.8]) and miR-4429 (3.8 [1.1 to 13.4]). Pathways analysis identified TGF-β signaling and Wnt/ β-catenin signaling among the top canonical pathways expected to be altered with visceral adiposity based on projected mRNA targets for the 55 differentially expressed miRNAs. A select mRNA target was validated in vitro. Conclusion These data show that visceral adipocytes shed exosomal-mediators predicted to regulate key end-organ inflammatory and fibrotic signaling pathways. PMID:25518011

Gap Junction Regulation of Vascular Tone: Implications of Modulatory Intercellular Communication During Gestation

PubMed Central

Ampey, Bryan C.; Morschauser, Timothy J.; Lampe, Paul D.

2017-01-01

In the vasculature, gap junctions (GJ) play a multifaceted role by serving as direct conduits for cell–cell intercellular communication via the facilitated diffusion of signaling molecules. GJs are essential for the control of gene expression and coordinated vascular development in addition to vascular function. The coupling of endothelial cells to each other, as well as with vascular smooth muscle cells via GJs, plays a relevant role in the control of vasomotor tone, tissue perfusion and arterial blood pressure. The regulation of cell-signaling is paramount to cardiovascular adaptations of pregnancy. Pregnancy requires highly developed cell-to-cell coupling, which is affected partly through the formation of intercellular GJs by Cx43, a gap junction protein, within adjacent cell membranes to help facilitate the increase of uterine blood flow (UBF) in order to ensure adequate perfusion for nutrient and oxygen delivery to the placenta and thus the fetus. One mode of communication that plays a critical role in regulating Cx43 is the release of endothelial-derived vasodilators such as prostacyclin (PGI2) and nitric oxide (NO) and their respective signaling mechanisms involving second messengers (cAMP and cGMP, respectively) that are likely to be important in maintaining UBF. Therefore, the assertion we present in this review is that GJs play an integral if not a central role in maintaining UBF by controlling rises in vasodilators (PGI2 and NO) via cyclic nucleotides. In this review, we discuss: (1) GJ structure and regulation; (2) second messenger regulation of GJ phosphorylation and formation; (3) pregnancy-induced changes in cell-signaling; and (4) the role of uterine arterial endothelial GJs during gestation. These topics integrate the current knowledge of this scientific field with interpretations and hypotheses regarding the vascular effects that are mediated by GJs and their relationship with vasodilatory vascular adaptations required for modulating the dramatic physiological rises in uteroplacental perfusion and blood flow observed during normal pregnancy. PMID:25015806