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Fan X, Yuan W, Huang W, Lin Z. Recent progress in leptin signaling from a structural perspective and its implications for diseases. Biochimie 2023; 212:60-75. [PMID: 37080418 DOI: 10.1016/j.biochi.2023.04.011] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2023] [Revised: 03/14/2023] [Accepted: 04/17/2023] [Indexed: 04/22/2023]
Abstract
As a multi-potency cytokine, leptin not only plays a crucial role in controlling weight and energy homeostasis but also participates in the metabolic balance in the human body. Leptin is a small helical protein with a molecular weight of 16 kDa. It can interact with multiple subtypes of its receptors to initiate intracellular signal transduction and exerts physiological effects. Disturbances in leptin signaling may lead to obesity and a variety of metabolic diseases. Leptin was also found to be a critical factor in many diseases of the elderly. In this review, we focus on recent advances in the structural and molecular mechanisms of leptin signaling through its receptors with the aim of a deeper understanding of leptin-related diseases.
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Affiliation(s)
- Xiao Fan
- School of Life Sciences, Tianjin University, Tianjin, 300072, PR China
| | - Wensu Yuan
- School of Life Sciences, Tianjin University, Tianjin, 300072, PR China
| | - Weidong Huang
- Department of Biochemistry and Molecular Biology, School of Basic Medicine, Ningxia Medical University, Yinchuan, Ningxia, 750004, PR China.
| | - Zhi Lin
- School of Life Sciences, Tianjin University, Tianjin, 300072, PR China.
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2
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Oliveira LDC, Morais GP, de Oliveira FP, Mata MM, Vera ASC, da Rocha AL, Elias LLK, Teixeira GR, de Moraes C, Cintra DE, Ropelle ER, de Moura LP, Pauli JR, de Freitas EC, Rorato R, da Silva ASR. Intermittent fasting combined with exercise training reduces body mass and alleviates hypothalamic disorders induced by high-fat diet intake. J Nutr Biochem 2023:109372. [PMID: 37169229 DOI: 10.1016/j.jnutbio.2023.109372] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2022] [Revised: 04/20/2023] [Accepted: 05/06/2023] [Indexed: 05/13/2023]
Abstract
High-fat diet consumption causes hypothalamic inflammation, dysregulating the leptin pathway, which, in turn, compromises the modulation of hypothalamic neuronal activities and predisposes obesity development. Intermittent fasting (IF) and exercise training (ET) have been demonstrated as efficient interventions to modulate hypothalamic inflammation and neuronal activity. However, no studies have evaluated whether combining these interventions could induce better results in reestablishing hypothalamic homeostasis disrupted by high-fat diet intake. The 8-week-old male C57BL/6 mice were randomly assigned into two groups: sedentary mice fed a standard diet (CT), and sedentary mice fed a high-fat diet (HF). After 8 weeks of an HF diet, part of the HF group (now 16 weeks old) was randomly subjected to different interventions for 6 weeks: HF-IF = HF diet mice submitted to IF; HF-T = HF diet mice submitted to ET; HF-IFT = HF diet mice submitted to IF and ET. All interventions decreased the body weight gain induced by high-fat diet intake, associated with reduced calorie consumption in week 14. Only the HF-IFT group presented improved serum insulin, leptin, resistin, and Tnf-alpha levels concomitantly with decreased hypothalamic inflammation. The HF-IFT group also demonstrated increased Pomc mRNA expression associated with enhanced pSTAT3 expression in the hypothalamic arcuate and ventromedial hypothalamic nuclei. Our data indicate that the beneficial effects of the combination of IF and ET on energy homeostasis are associated with increased leptin sensitivity in the hypothalamic arcuate nucleus and ventromedial hypothalamic nucleus, which is likely due to an improvement in hypothalamic inflammatory pathways in these nuclei.
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Affiliation(s)
- Luciana da Costa Oliveira
- Postgraduate Program in Rehabilitation and Functional Performance, Ribeirão Preto Medical School, University of São Paulo (USP), Ribeirão Preto, São Paulo, Brazil
| | - Gustavo Paroschi Morais
- Postgraduate Program in Rehabilitation and Functional Performance, Ribeirão Preto Medical School, University of São Paulo (USP), Ribeirão Preto, São Paulo, Brazil
| | - Franciane Pereira de Oliveira
- Laboratory of Stress Neuroendocrinology, Department of Biophysics, Paulista Medical School, Federal University of Sao Paulo, Sao Paulo, SP, Brazil
| | - Milene Montavoni Mata
- Departament of Physiology, Ribeirão Preto Medical School, University of São Paulo, Brazil
| | - Allice Santos Cruz Vera
- Multicenter Graduate Program in Physiological Sciences, São Paulo State University (UNESP), Presidente Prudente, SP, Brazil
| | - Alisson Luiz da Rocha
- School of Physical Education and Sport of Ribeirão Preto, University of São Paulo (USP), Ribeirão Preto, São Paulo, Brazil
| | | | - Giovana Rampazzo Teixeira
- Multicenter Graduate Program in Physiological Sciences, São Paulo State University (UNESP), Presidente Prudente, SP, Brazil
| | - Camila de Moraes
- Laboratory of Molecular Biology of Exercise (LaBMEx), School of Applied Sciences, University of Campinas (UNICAMP), Limeira, São Paulo, Brazil
| | - Dennys E Cintra
- School of Physical Education and Sport of Ribeirão Preto, University of São Paulo (USP), Ribeirão Preto, São Paulo, Brazil
| | - Eduardo R Ropelle
- School of Physical Education and Sport of Ribeirão Preto, University of São Paulo (USP), Ribeirão Preto, São Paulo, Brazil
| | - Leandro P de Moura
- School of Physical Education and Sport of Ribeirão Preto, University of São Paulo (USP), Ribeirão Preto, São Paulo, Brazil
| | - José R Pauli
- School of Physical Education and Sport of Ribeirão Preto, University of São Paulo (USP), Ribeirão Preto, São Paulo, Brazil
| | - Ellen C de Freitas
- Laboratory of Molecular Biology of Exercise (LaBMEx), School of Applied Sciences, University of Campinas (UNICAMP), Limeira, São Paulo, Brazil
| | - Rodrigo Rorato
- Laboratory of Stress Neuroendocrinology, Department of Biophysics, Paulista Medical School, Federal University of Sao Paulo, Sao Paulo, SP, Brazil
| | - Adelino Sanchez R da Silva
- Postgraduate Program in Rehabilitation and Functional Performance, Ribeirão Preto Medical School, University of São Paulo (USP), Ribeirão Preto, São Paulo, Brazil.; Laboratory of Molecular Biology of Exercise (LaBMEx), School of Applied Sciences, University of Campinas (UNICAMP), Limeira, São Paulo, Brazil..
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3
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Kuraku S, Kaiya H, Tanaka T, Hyodo S. Evolution of Vertebrate Hormones and Their Receptors: Insights from Non-Osteichthyan Genomes. Annu Rev Anim Biosci 2023; 11:163-182. [PMID: 36400012 DOI: 10.1146/annurev-animal-050922-071351] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Homeostatic control and reproductive functions of humans are regulated at the molecular levels largely by peptide hormones secreted from endocrine and/or neuroendocrine cells in the central nervous system and peripheral organs. Homologs of those hormones and their receptors function similarly in many vertebrate species distantly related to humans, but the evolutionary history of the endocrine system involving those factors has been obscured by the scarcity of genome DNA sequence information of some taxa that potentially contain their orthologs. Focusing on non-osteichthyan vertebrates, namely jawless and cartilaginous fishes, this article illustrates how investigating genome sequence information assists our understanding of the diversification of vertebrate gene repertoires in four broad themes: (a) the presence or absence of genes, (b) multiplication and maintenance of paralogs, (c) differential fates of duplicated paralogs, and (d) the evolutionary timing of gene origins.
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Affiliation(s)
- Shigehiro Kuraku
- Molecular Life History Laboratory, Department of Genomics and Evolutionary Biology, National Institute of Genetics, Mishima, Japan; .,Department of Genetics, Sokendai (Graduate University for Advanced Studies), Mishima, Japan.,Laboratory for Phyloinformatics, RIKEN Center for Biosystems Dynamics Research (BDR), Kobe, Japan
| | - Hiroyuki Kaiya
- Grandsoul Research Institute of Immunology, Inc., Uda, Japan
| | - Tomohiro Tanaka
- Department of Gastroenterology and Metabolism, Graduate School of Medical Sciences, Nagoya City University, Nagoya, Japan
| | - Susumu Hyodo
- Laboratory of Physiology, Atmosphere and Ocean Research Institute, The University of Tokyo, Kashiwa, Japan
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4
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Recent Advances in the Knowledge of the Mechanisms of Leptin Physiology and Actions in Neurological and Metabolic Pathologies. Int J Mol Sci 2023; 24:ijms24021422. [PMID: 36674935 PMCID: PMC9860943 DOI: 10.3390/ijms24021422] [Citation(s) in RCA: 20] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2022] [Revised: 01/05/2023] [Accepted: 01/07/2023] [Indexed: 01/13/2023] Open
Abstract
Excess body weight is frequently associated with low-grade inflammation. Evidence indicates a relationship between obesity and cancer, as well as with other diseases, such as diabetes and non-alcoholic fatty liver disease, in which inflammation and the actions of various adipokines play a role in the pathological mechanisms involved in these disorders. Leptin is mainly produced by adipose tissue in proportion to fat stores, but it is also synthesized in other organs, where leptin receptors are expressed. This hormone performs numerous actions in the brain, mainly related to the control of energy homeostasis. It is also involved in neurogenesis and neuroprotection, and central leptin resistance is related to some neurological disorders, e.g., Parkinson's and Alzheimer's diseases. In peripheral tissues, leptin is implicated in the regulation of metabolism, as well as of bone density and muscle mass. All these actions can be affected by changes in leptin levels and the mechanisms associated with resistance to this hormone. This review will present recent advances in the molecular mechanisms of leptin action and their underlying roles in pathological situations, which may be of interest for revealing new approaches for the treatment of diseases where the actions of this adipokine might be compromised.
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Wee NKY, de Lima TFC, McGregor NE, Walker EC, Poulton IJ, Blank M, Sims NA. Leptin receptor in osteocytes promotes cortical bone consolidation in female mice. J Endocrinol 2022; 255:25-37. [PMID: 35938692 DOI: 10.1530/joe-22-0084] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/03/2022] [Accepted: 08/01/2022] [Indexed: 11/08/2022]
Abstract
Bone strength is partially determined during cortical bone consolidation, a process comprising coalescence of peripheral trabecular bone and its progressive mineralisation. Mice with genetic deletion of suppressor of cytokine signalling 3 (Socs3), an inhibitor of STAT3 signalling, exhibit delayed cortical bone consolidation, indicated by high cortical porosity, low mineral content, and low bone strength. Since leptin receptor (LepR) is expressed in the osteoblast lineage and is suppressed by SOCS3, we evaluated whether LepR deletion in osteocytes would rectify the Dmp1cre.Socs3fl/fl bone defect. First, we tested LepR deletion in osteocytes by generating Dmp1cre.LepRfl/fl mice and detected no significant bone phenotype. We then generated Dmp1cre.Socs3fl/fl.LepRfl/fl mice and compared them to Dmp1cre.Socs3fl/fl controls. Between 6 and 12 weeks of age, both Dmp1cre.Socs3fl/fl.LepRfl/fl and control (Dmp1cre.Socs3fl/fl) mice showed an increasing proportion of more heavily mineralised bone, indicating some cortical consolidation with time. However, at 12 weeks of age, rather than resolving the phenotype, delayed consolidation was extended in female Dmp1cre.Socs3fl/fl.LepRfl/fl mice. This was indicated in both metaphysis and diaphysis by greater proportions of low-density bone, lower proportions of high-density bone, and greater cortical porosity than Dmp1cre.Socs3fl/fl controls. There was also no change in the proportion of osteocytes staining positive for phospho-STAT3, suggesting the effect of LepR deletion in Dmp1cre.Socs3fl/fl mice is STAT3-independent. This identifies a new role for leptin signalling in bone which opposes our original hypothesis. Although LepR in osteocytes has no irreplaceable physiological role in normal bone maturation, when STAT3 is hyperactive, LepR in Dmp1Cre-expressing cells supports cortical consolidation.
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Affiliation(s)
- Natalie K Y Wee
- Bone Cell Biology and Disease Unit, St Vincent's Institute of Medical Research, Fitzroy, Australia
| | - Thaísa F C de Lima
- Bone Cell Biology and Disease Unit, St Vincent's Institute of Medical Research, Fitzroy, Australia
- Department of Genetics and Molecular Biology, University of Campinas, São Paulo, Brazil
| | - Narelle E McGregor
- Bone Cell Biology and Disease Unit, St Vincent's Institute of Medical Research, Fitzroy, Australia
| | - Emma C Walker
- Bone Cell Biology and Disease Unit, St Vincent's Institute of Medical Research, Fitzroy, Australia
| | - Ingrid J Poulton
- Bone Cell Biology and Disease Unit, St Vincent's Institute of Medical Research, Fitzroy, Australia
| | - Martha Blank
- Bone Cell Biology and Disease Unit, St Vincent's Institute of Medical Research, Fitzroy, Australia
- Department of Medicine, The University of Melbourne, St. Vincent's Hospital, Melbourne, Australia
| | - Natalie A Sims
- Bone Cell Biology and Disease Unit, St Vincent's Institute of Medical Research, Fitzroy, Australia
- Department of Medicine, The University of Melbourne, St. Vincent's Hospital, Melbourne, Australia
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6
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Naser W, Maymand S, Rivera LR, Connor T, Liongue C, Smith CM, Aston-Mourney K, McCulloch DR, McGee SL, Ward AC. Cytokine-inducible SH2 domain containing protein contributes to regulation of adiposity, food intake, and glucose metabolism. FASEB J 2022; 36:e22320. [PMID: 35470501 DOI: 10.1096/fj.202101882r] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2021] [Revised: 03/24/2022] [Accepted: 04/06/2022] [Indexed: 01/03/2023]
Abstract
The cytokine-inducible SH2 domain containing protein (CISH) is the founding member of the suppressor of cytokine signaling (SOCS) family of negative feedback regulators and has been shown to be a physiological regulator of signaling in immune cells. This study sought to investigate novel functions for CISH outside of the immune system. Mice deficient in CISH were generated and analyzed using a range of metabolic and other parameters, including in response to a high fat diet and leptin administration. CISH knockout mice possessed decreased body fat and showed resistance to diet-induced obesity. This was associated with reduced food intake, but unaltered energy expenditure and microbiota composition. CISH ablation resulted in reduced basal expression of the orexigenic Agrp gene in the arcuate nucleus (ARC) region of the brain. Cish was basally expressed in the ARC, with evidence of co-expression with the leptin receptor (Lepr) gene in Agrp-positive neurons. CISH-deficient mice also showed enhanced leptin responsiveness, although Cish expression was not itself modulated by leptin. CISH-deficient mice additionally exhibited improved insulin sensitivity on a high-fat diet, but not glucose tolerance despite reduced body weight. These data identify CISH as an important regulator of homeostasis through impacts on appetite control, mediated at least in part by negative regulation of the anorexigenic effects of leptin, and impacts on glucose metabolism.
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Affiliation(s)
- Wasan Naser
- School of Medicine, Deakin University, Geelong, Victoria, Australia.,College of Science, University of Baghdad, Baghdad, Iraq
| | - Saeed Maymand
- School of Medicine, Deakin University, Geelong, Victoria, Australia
| | - Leni R Rivera
- School of Medicine, Deakin University, Geelong, Victoria, Australia.,IMPACT, Deakin University, Geelong, Victoria, Australia
| | - Timothy Connor
- School of Medicine, Deakin University, Geelong, Victoria, Australia
| | - Clifford Liongue
- School of Medicine, Deakin University, Geelong, Victoria, Australia.,IMPACT, Deakin University, Geelong, Victoria, Australia
| | - Craig M Smith
- School of Medicine, Deakin University, Geelong, Victoria, Australia.,IMPACT, Deakin University, Geelong, Victoria, Australia
| | - Kathryn Aston-Mourney
- School of Medicine, Deakin University, Geelong, Victoria, Australia.,IMPACT, Deakin University, Geelong, Victoria, Australia
| | - Daniel R McCulloch
- School of Medicine, Deakin University, Geelong, Victoria, Australia.,IMPACT, Deakin University, Geelong, Victoria, Australia
| | - Sean L McGee
- School of Medicine, Deakin University, Geelong, Victoria, Australia.,IMPACT, Deakin University, Geelong, Victoria, Australia
| | - Alister C Ward
- School of Medicine, Deakin University, Geelong, Victoria, Australia.,IMPACT, Deakin University, Geelong, Victoria, Australia
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7
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Oliveira LDC, Morais GP, Ropelle ER, de Moura LP, Cintra DE, Pauli JR, de Freitas EC, Rorato R, da Silva ASR. Using Intermittent Fasting as a Non-pharmacological Strategy to Alleviate Obesity-Induced Hypothalamic Molecular Pathway Disruption. Front Nutr 2022; 9:858320. [PMID: 35445066 PMCID: PMC9014844 DOI: 10.3389/fnut.2022.858320] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2022] [Accepted: 02/25/2022] [Indexed: 12/18/2022] Open
Abstract
Intermittent fasting (IF) is a popular intervention used to fight overweight/obesity. This condition is accompanied by hypothalamic inflammation, limiting the proper signaling of molecular pathways, with consequent dysregulation of food intake and energy homeostasis. This mini-review explored the therapeutic modulation potential of IF regarding the disruption of these molecular pathways. IF seems to modulate inflammatory pathways in the brain, which may also be correlated with the brain-microbiota axis, improving hypothalamic signaling of leptin and insulin, and inducing the autophagic pathway in hypothalamic neurons, contributing to weight loss in obesity. Evidence also suggests that when an IF protocol is performed without respecting the circadian cycle, it can lead to dysregulation in the expression of circadian cycle regulatory genes, with potential health damage. In conclusion, IF may have the potential to be an adjuvant treatment to improve the reestablishment of hypothalamic responses in obesity.
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Affiliation(s)
- Luciana da Costa Oliveira
- Postgraduate Program in Rehabilitation and Functional Performance, Ribeirão Preto Medical School, University of São Paulo, São Paulo, Brazil
| | - Gustavo Paroschi Morais
- Postgraduate Program in Rehabilitation and Functional Performance, Ribeirão Preto Medical School, University of São Paulo, São Paulo, Brazil
| | - Eduardo R. Ropelle
- Laboratory of Molecular Biology of Exercise, School of Applied Sciences, University of Campinas, São Paulo, Brazil
| | - Leandro P. de Moura
- Laboratory of Molecular Biology of Exercise, School of Applied Sciences, University of Campinas, São Paulo, Brazil
| | - Dennys E. Cintra
- Laboratory of Molecular Biology of Exercise, School of Applied Sciences, University of Campinas, São Paulo, Brazil
| | - José R. Pauli
- Laboratory of Molecular Biology of Exercise, School of Applied Sciences, University of Campinas, São Paulo, Brazil
| | - Ellen C. de Freitas
- School of Physical Education and Sport of Ribeirão Preto, University of São Paulo, São Paulo, Brazil
| | - Rodrigo Rorato
- Postgraduate Program in Molecular Biology, Laboratory of Stress Neuroendocrinology, Department of Biophysics, Paulista Medical School, Federal University of São Paulo, São Paulo, Brazil
- Rodrigo Rorato,
| | - Adelino Sanchez R. da Silva
- Postgraduate Program in Rehabilitation and Functional Performance, Ribeirão Preto Medical School, University of São Paulo, São Paulo, Brazil
- School of Physical Education and Sport of Ribeirão Preto, University of São Paulo, São Paulo, Brazil
- *Correspondence: Adelino Sanchez R. da Silva,
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Vohra MS, Benchoula K, Serpell CJ, Hwa WE. AgRP/NPY and POMC neurons in the arcuate nucleus and their potential role in treatment of obesity. Eur J Pharmacol 2022; 915:174611. [PMID: 34798121 DOI: 10.1016/j.ejphar.2021.174611] [Citation(s) in RCA: 47] [Impact Index Per Article: 23.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2021] [Revised: 10/27/2021] [Accepted: 10/27/2021] [Indexed: 02/08/2023]
Abstract
Obesity is a major health crisis affecting over a third of the global population. This multifactorial disease is regulated via interoceptive neural circuits in the brain, whose alteration results in excessive body weight. Certain central neuronal populations in the brain are recognised as crucial nodes in energy homeostasis; in particular, the hypothalamic arcuate nucleus (ARC) region contains two peptide microcircuits that control energy balance with antagonistic functions: agouti-related peptide/neuropeptide-Y (AgRP/NPY) signals hunger and stimulates food intake; and pro-opiomelanocortin (POMC) signals satiety and reduces food intake. These neuronal peptides levels react to energy status and integrate signals from peripheral ghrelin, leptin, and insulin to regulate feeding and energy expenditure. To manage obesity comprehensively, it is crucial to understand cellular and molecular mechanisms of information processing in ARC neurons, since these regulate energy homeostasis. Importantly, a specific strategy focusing on ARC circuits needs to be devised to assist in treating obese patients and maintaining weight loss with minimal or no side effects. The aim of this review is to elucidate the recent developments in the study of AgRP-, NPY- and POMC-producing neurons, specific to their role in controlling metabolism. The impact of ghrelin, leptin, and insulin signalling via action of these neurons is also surveyed, since they also impact energy balance through this route. Lastly, we present key proteins, targeted genes, compounds, drugs, and therapies that actively work via these neurons and could potentially be used as therapeutic targets for treating obesity conditions.
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Affiliation(s)
- Muhammad Sufyan Vohra
- School of Medicine, Faculty of Health and Medical Sciences, Taylor's University Lakeside Campus, 47500, Subang Jaya, Selangor Darul Ehsan, Malaysia
| | - Khaled Benchoula
- School of Medicine, Faculty of Health and Medical Sciences, Taylor's University Lakeside Campus, 47500, Subang Jaya, Selangor Darul Ehsan, Malaysia
| | - Christopher J Serpell
- School of Physical Sciences, Ingram Building, University of Kent, Canterbury, Kent, CT2 7NH, United Kingdom
| | - Wong Eng Hwa
- School of Medicine, Faculty of Health and Medical Sciences, Taylor's University Lakeside Campus, 47500, Subang Jaya, Selangor Darul Ehsan, Malaysia.
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IL-6 family cytokines as potential therapeutic strategies to treat metabolic diseases. Cytokine 2021; 144:155549. [PMID: 33962843 DOI: 10.1016/j.cyto.2021.155549] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Revised: 04/12/2021] [Accepted: 04/14/2021] [Indexed: 02/06/2023]
Abstract
Metabolic disease is highly prevalent. Here we discuss the therapeutic utility of using gp130 receptor ligands as a therapeutic strategy to treat metabolic disease.
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10
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Chen C, Zhou Y, Huang R, Wang M, Li Y, Li J. [Bile acids regulate anorexigenic neuropeptide through p-STAT3-SOCS3 signaling in mouse hypothalamic cells]. NAN FANG YI KE DA XUE XUE BAO = JOURNAL OF SOUTHERN MEDICAL UNIVERSITY 2020; 40:1001-1007. [PMID: 32895154 DOI: 10.12122/j.issn.1673-4254.2020.07.13] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
OBJECTIVE To explore the effects of taurolithocholic acid (tLCA) and chenodeoxycholic acid (CDCA) on the expression of aorexigenic neuropeptide in mouse hypothalamus GT1-7 cells. METHODS Mouse hypothalamic GT1-7 cells were treated with culture medium containing 10% FBS (control group, n=3) or with 10 nmol/L, 100 nmol/L, 1 μmol/L and 10 μmol/L tLCA (tLCA group, n=3) or CDCA (CDCA group, n=3) for 12, 24 or 48 h. Real-time PCR was performed to determine the expression levels of proopiomelanocortin (POMC) mRNA in the cells, and the production levels of α-melanocyte-stimulating hormone (α-MSH) were assessed using an ELISA kit. Signal transduction and activator of transcription 3 phosphorylation (p-STAT3), threonine kinase phosphorylation (p-AKT), suppressor of cytokine signaling 3 (SOCS3), G protein-coupled bile acid receptor-1 (TGR5) and farnesoid X receptor (FXR) protein were detected by Western blotting. RESULTS Western blotting results showed that mouse hypothalamic GT1-7 cells expressed two bile acid receptors, TGR5 and FXR, whose expressions were regulated by bile acids. Real-time PCR showed that the expression of POMC mRNA was significantly increased in the cells after treatment with 10 μmol/L tLCA or CDCA for 24 h. POMC-derived anorexigenic peptide α-MSH increased significantly in GT1-7 cells after treatment with 10 μmol/L tLCA or CDCA for 24 h. Treatment of the cells with tLCA or CDCA significantly increased the expressions of intracellular signaling proteins including p-STAT3, p-AKT and SOCS3. CONCLUSIONS Mouse hypothalamic GT1-7 cells express bile acid receptors TGR5 and FXR. Bile acids tLCA or CDCA can promote the expression of POMC mRNA and increase the production of the anorexigenic peptide α-MSH. The intracellular signaling proteins p-AKT, p-STAT3 and SOCS3 are likely involved in bile acid-induced anorexigenic peptide production.
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Affiliation(s)
- Chunxiu Chen
- Department of Nutrition and Food Hygiene, School of Public Health and Management, Chongqing 400016, China.,Chongqing Key Laboratory of Translational Medicine in Major Metabolic Diseases, First Affiliated Hospital of Chongqing Medical University, Chongqing 400016, China
| | - Yong Zhou
- People's Hospital of Banan District, Chongqing 401320, China
| | - Rongfeng Huang
- Chongqing Key Laboratory of Translational Medicine in Major Metabolic Diseases, First Affiliated Hospital of Chongqing Medical University, Chongqing 400016, China
| | - Miaoran Wang
- Department of Nutrition and Food Hygiene, School of Public Health and Management, Chongqing 400016, China.,Chongqing Key Laboratory of Translational Medicine in Major Metabolic Diseases, First Affiliated Hospital of Chongqing Medical University, Chongqing 400016, China
| | - Yue Li
- Department of Nutrition and Food Hygiene, School of Public Health and Management, Chongqing 400016, China.,Chongqing Key Laboratory of Translational Medicine in Major Metabolic Diseases, First Affiliated Hospital of Chongqing Medical University, Chongqing 400016, China
| | - Jibin Li
- Department of Nutrition and Food Hygiene, School of Public Health and Management, Chongqing 400016, China
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11
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Modulation of the IL-6-Signaling Pathway in Liver Cells by miRNAs Targeting gp130, JAK1, and/or STAT3. MOLECULAR THERAPY. NUCLEIC ACIDS 2019; 16:419-433. [PMID: 31026677 PMCID: PMC6479786 DOI: 10.1016/j.omtn.2019.03.007] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/21/2018] [Revised: 03/22/2019] [Accepted: 03/24/2019] [Indexed: 12/19/2022]
Abstract
Interleukin-6 (IL-6)-type cytokines share the common receptor glycoprotein 130 (gp130), which activates a signaling cascade involving Janus kinases (JAKs) and signal transducer and activator of transcription (STAT) transcription factors. IL-6 and/or its signaling pathway is often deregulated in diseases, such as chronic liver diseases and cancer. Thus, the identification of compounds inhibiting this pathway is of interest for future targeted therapies. We established novel cellular screening systems based on a STAT-responsive reporter gene (Cypridina luciferase). Of a library containing 538 microRNA (miRNA) mimics, several miRNAs affected hyper-IL-6-induced luciferase activities. When focusing on candidate miRNAs specifically targeting 3′ UTRs of signaling molecules of this pathway, we identified, e.g., miR-3677-5p as a novel miRNA affecting protein expression of both STAT3 and JAK1, whereas miR-16-1-3p, miR-4473, and miR-520f-3p reduced gp130 surface expression. Interestingly, combination treatment with 2 or 3 miRNAs targeting gp130 or different signaling molecules of the pathway did not increase the inhibitory effects on phospho-STAT3 levels and STAT3 target gene expression compared to treatment with single mimics. Taken together, we identified a set of miRNAs of potential therapeutic value for cancer and inflammatory diseases, which directly target the expression of molecules within the IL-6-signaling pathway and can dampen inflammatory signal transduction.
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12
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Wang Z, do Carmo JM, da Silva AA, Bailey KC, Aberdein N, Moak SP, Hall JE. Role of SOCS3 in POMC neurons in metabolic and cardiovascular regulation. Am J Physiol Regul Integr Comp Physiol 2019; 316:R338-R351. [PMID: 30673296 PMCID: PMC6483217 DOI: 10.1152/ajpregu.00163.2018] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2018] [Revised: 01/16/2019] [Accepted: 01/17/2019] [Indexed: 02/08/2023]
Abstract
Suppressor of cytokine signaling 3 (SOCS3) is a negative regulator of leptin signaling. We previously showed that the chronic effects of leptin on blood pressure (BP) and glucose regulation are mediated by stimulation of proopiomelanocortin (POMC) neurons. In this study we examined the importance of endogenous SOCS3 in POMC neurons in control of metabolic and cardiovascular function and potential sex differences. Male and female SOCS3flox/flox/POMC-Cre mice in which SOCS3 was selectively deleted in POMC neurons and control SOCS3flox/flox mice were studied during a control diet (CD) or a high-fat diet (HFD) and during chronic leptin infusion. Body weight was lower in male and female SOCS3flox/flox/POMC-Cre than control mice fed the CD, despite similar food intake. Male SOCS3flox/flox/POMC-Cre mice exhibited increased energy expenditure. BP and heart rate were similar in male and female SOCS3flox/flox/POMC-Cre and control mice fed the CD. HFD-fed male and female SOCS3flox/flox/POMC-Cre mice showed attenuated weight gain. HFD-induced elevations in baseline BP and BP responses to an air-jet stress test were greater in female SOCS3flox/flox/POMC-Cre than control mice. Chronic leptin infusion produced similar responses for food intake, body weight, oxygen consumption, blood glucose, BP, and heart rate in all groups. Thus SOCS3 deficiency in POMC neurons influences body weight regulation in the setting of CD and HFD and differentially affects BP and energy balance in a sex-specific manner but does not amplify the dietary, glycemic, or cardiovascular effects of leptin.
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Affiliation(s)
- Zhen Wang
- Department of Physiology and Biophysics, University of Mississippi Medical Center , Jackson, Mississippi
- Mississippi Center for Obesity Research, University of Mississippi Medical Center , Jackson, Mississippi
| | - Jussara M do Carmo
- Department of Physiology and Biophysics, University of Mississippi Medical Center , Jackson, Mississippi
- Mississippi Center for Obesity Research, University of Mississippi Medical Center , Jackson, Mississippi
| | - Alexandre A da Silva
- Department of Physiology and Biophysics, University of Mississippi Medical Center , Jackson, Mississippi
- Mississippi Center for Obesity Research, University of Mississippi Medical Center , Jackson, Mississippi
| | - Kandice C Bailey
- Department of Physiology and Biophysics, University of Mississippi Medical Center , Jackson, Mississippi
- Mississippi Center for Obesity Research, University of Mississippi Medical Center , Jackson, Mississippi
| | - Nicola Aberdein
- Biomolecular Science Research Centre, Sheffield Hallam University , Sheffield , United Kingdom
| | - Sydney P Moak
- Department of Physiology and Biophysics, University of Mississippi Medical Center , Jackson, Mississippi
- Mississippi Center for Obesity Research, University of Mississippi Medical Center , Jackson, Mississippi
| | - John E Hall
- Department of Physiology and Biophysics, University of Mississippi Medical Center , Jackson, Mississippi
- Mississippi Center for Obesity Research, University of Mississippi Medical Center , Jackson, Mississippi
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13
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Baldini G, Phelan KD. The melanocortin pathway and control of appetite-progress and therapeutic implications. J Endocrinol 2019; 241:R1-R33. [PMID: 30812013 PMCID: PMC6500576 DOI: 10.1530/joe-18-0596] [Citation(s) in RCA: 125] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/11/2019] [Accepted: 01/22/2019] [Indexed: 12/19/2022]
Abstract
The initial discovery that ob/ob mice become obese because of a recessive mutation of the leptin gene has been crucial to discover the melanocortin pathway to control appetite. In the melanocortin pathway, the fed state is signaled by abundance of circulating hormones such as leptin and insulin, which bind to receptors expressed at the surface of pro-opiomelanocortin (POMC) neurons to promote processing of POMC to the mature hormone α-melanocyte-stimulating hormone (α-MSH). The α-MSH released by POMC neurons then signals to decrease energy intake by binding to melanocortin-4 receptor (MC4R) expressed by MC4R neurons to the paraventricular nucleus (PVN). Conversely, in the 'starved state' activity of agouti-related neuropeptide (AgRP) and of neuropeptide Y (NPY)-expressing neurons is increased by decreased levels of circulating leptin and insulin and by the orexigenic hormone ghrelin to promote food intake. This initial understanding of the melanocortin pathway has recently been implemented by the description of the complex neuronal circuit that controls the activity of POMC, AgRP/NPY and MC4R neurons and downstream signaling by these neurons. This review summarizes the progress done on the melanocortin pathway and describes how obesity alters this pathway to disrupt energy homeostasis. We also describe progress on how leptin and insulin receptors signal in POMC neurons, how MC4R signals and how altered expression and traffic of MC4R change the acute signaling and desensitization properties of the receptor. We also describe how the discovery of the melanocortin pathway has led to the use of melanocortin agonists to treat obesity derived from genetic disorders.
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Affiliation(s)
- Giulia Baldini
- Department of Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA
| | - Kevin D. Phelan
- Department of Neurobiology & Developmental Sciences, University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA
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14
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Guo Q, Zheng R, Huang J, He M, Wang Y, Guo Z, Sun L, Chen P. Using Integrative Analysis of DNA Methylation and Gene Expression Data in Multiple Tissue Types to Prioritize Candidate Genes for Drug Development in Obesity. Front Genet 2018; 9:663. [PMID: 30619480 PMCID: PMC6305755 DOI: 10.3389/fgene.2018.00663] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2018] [Accepted: 12/04/2018] [Indexed: 12/25/2022] Open
Abstract
Obesity has become a major public health issue which is caused by a combination of genetic and environmental factors. Genome-wide DNA methylation studies have identified that DNA methylation at Cytosine-phosphate-Guanine (CpG) sites are associated with obesity. However, subsequent functional validation of the results from these studies has been challenging given the high number of reported associations. In this study, we applied an integrative analysis approach, aiming to prioritize the drug development candidate genes from many associated CpGs. Association data was collected from previous genome-wide DNA methylation studies and combined using a sample-size-weighted strategy. Gene expression data in adipose tissues and enriched pathways of the affiliated genes were overlapped, to shortlist the associated CpGs. The CpGs with the most overlapping evidence were indicated as the most appropriate CpGs for future studies. Our results revealed that 119 CpGs were associated with obesity (p ≤ 1.03 × 10−7). Of the affiliated genes, SOCS3 was the only gene involved in all enriched pathways and was differentially expressed in both visceral adipose tissue (VAT) and subcutaneous adipose tissue (SAT). In conclusion, our integrative analysis is an effective approach in highlighting the DNA methylation with the highest drug development relevance. SOCS3 may serve as a target for drug development of obesity and its complications.
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Affiliation(s)
- Qingjie Guo
- Department of Genetics, College of Basic Medical Sciences, Jilin University, Changchun, China.,Key Laboratory of Pathobiology, Ministry of Education, Jilin University, Changchun, China
| | - Ruonan Zheng
- College of Clinical Medicine, Jilin University, Changchun, China
| | - Jiarui Huang
- College of Clinical Medicine, Jilin University, Changchun, China
| | - Meng He
- College of Clinical Medicine, Jilin University, Changchun, China
| | - Yuhan Wang
- College of Clinical Medicine, Jilin University, Changchun, China
| | - Zonghao Guo
- College of Clinical Medicine, Jilin University, Changchun, China
| | - Liankun Sun
- Department of Pathophysiology, College of Basic Medical Sciences, Jilin University, Changchun, China
| | - Peng Chen
- Department of Genetics, College of Basic Medical Sciences, Jilin University, Changchun, China.,Key Laboratory of Pathobiology, Ministry of Education, Jilin University, Changchun, China
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15
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Gao Y, Zhao H, Wang P, Wang J, Zou L. The roles of SOCS3 and STAT3 in bacterial infection and inflammatory diseases. Scand J Immunol 2018; 88:e12727. [PMID: 30341772 DOI: 10.1111/sji.12727] [Citation(s) in RCA: 66] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2018] [Revised: 10/11/2018] [Accepted: 10/13/2018] [Indexed: 12/27/2022]
Affiliation(s)
- Yu Gao
- Translational Neuroscience & Neural Regeneration and Repair Institute/Institute of Cell Therapy; The People's Hospital of China Three Gorges University; Yichang China
- Department of Microbiology, Tumor and Cell Biology; Karolinska Institutet; Stockholm Sweden
| | - Honglei Zhao
- Translational Neuroscience & Neural Regeneration and Repair Institute/Institute of Cell Therapy; The People's Hospital of China Three Gorges University; Yichang China
- Department of Oncology-Pathology; Karolinska Institutet; Stockholm Sweden
| | - Peng Wang
- Translational Neuroscience & Neural Regeneration and Repair Institute/Institute of Cell Therapy; The People's Hospital of China Three Gorges University; Yichang China
| | - Jun Wang
- Translational Neuroscience & Neural Regeneration and Repair Institute/Institute of Cell Therapy; The People's Hospital of China Three Gorges University; Yichang China
| | - Lili Zou
- Translational Neuroscience & Neural Regeneration and Repair Institute/Institute of Cell Therapy; The People's Hospital of China Three Gorges University; Yichang China
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16
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Olea-Flores M, Juárez-Cruz JC, Mendoza-Catalán MA, Padilla-Benavides T, Navarro-Tito N. Signaling Pathways Induced by Leptin during Epithelial⁻Mesenchymal Transition in Breast Cancer. Int J Mol Sci 2018; 19:E3493. [PMID: 30404206 PMCID: PMC6275018 DOI: 10.3390/ijms19113493] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2018] [Revised: 10/27/2018] [Accepted: 11/01/2018] [Indexed: 12/12/2022] Open
Abstract
Leptin is an adipokine that is overexpressed in obese and overweight people. Interestingly, women with breast cancer present high levels of leptin and of its receptor ObR. Leptin plays an important role in breast cancer progression due to the biological processes it participates in, such as epithelial⁻mesenchymal transition (EMT). EMT consists of a series of orchestrated events in which cell⁻cell and cell⁻extracellular matrix interactions are altered and lead to the release of epithelial cells from the surrounding tissue. The cytoskeleton is also re-arranged, allowing the three-dimensional movement of epithelial cells into the extracellular matrix. This transition provides cells with the ability to migrate and invade adjacent or distal tissues, which is a classic feature of invasive or metastatic carcinoma cells. In recent years, the number of cases of breast cancer has increased, making this disease a public health problem worldwide and the leading cause of death due to cancer in women. In this review, we focus on recent advances that establish: (1) leptin as a risk factor for the development of breast cancer, and (2) leptin as an inducer of EMT, an event that promotes tumor progression.
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Affiliation(s)
- Monserrat Olea-Flores
- Laboratorio de Biología Celular del Cáncer, Facultad de Ciencias Químico Biológicas, Universidad Autónoma de Guerrero, Av. Lázaro Cárdenas s/n, Chilpancingo, GRO 39090, México.
| | - Juan Carlos Juárez-Cruz
- Laboratorio de Biología Celular del Cáncer, Facultad de Ciencias Químico Biológicas, Universidad Autónoma de Guerrero, Av. Lázaro Cárdenas s/n, Chilpancingo, GRO 39090, México.
| | - Miguel A Mendoza-Catalán
- Laboratorio de Biomedicina Molecular, Facultad de Ciencias Químico Biológicas, Universidad Autónoma de Guerrero, Av. Lázaro Cárdenas s/n, Chilpancingo, GRO 39090, México.
| | - Teresita Padilla-Benavides
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, 364 Plantation Street, Worcester, MA 01605, USA.
| | - Napoleón Navarro-Tito
- Laboratorio de Biología Celular del Cáncer, Facultad de Ciencias Químico Biológicas, Universidad Autónoma de Guerrero, Av. Lázaro Cárdenas s/n, Chilpancingo, GRO 39090, México.
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17
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Rolvering C, Zimmer AD, Ginolhac A, Margue C, Kirchmeyer M, Servais F, Hermanns HM, Hergovits S, Nazarov PV, Nicot N, Kreis S, Haan S, Behrmann I, Haan C. The PD-L1- and IL6-mediated dampening of the IL27/STAT1 anticancer responses are prevented by α-PD-L1 or α-IL6 antibodies. J Leukoc Biol 2018; 104:969-985. [PMID: 30040142 DOI: 10.1002/jlb.ma1217-495r] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2018] [Revised: 06/15/2018] [Accepted: 06/18/2018] [Indexed: 12/19/2022] Open
Abstract
Interleukin-27 (IL27) is a type-I cytokine of the IL6/IL12 family and is predominantly secreted by activated macrophages and dendritic cells. We show that IL27 induces STAT factor phosphorylation in cancerous cell lines of different tissue origin. IL27 leads to STAT1 phosphorylation and recapitulates an IFN-γ-like response in the microarray analyses, with up-regulation of genes involved in antiviral defense, antigen presentation, and immune suppression. Like IFN-γ, IL27 leads to an up-regulation of TAP2 and MHC-I proteins, which mediate increased tumor immune clearance. However, both cytokines also upregulate proteins such as PD-L1 (CD274) and IDO-1, which are associated with immune escape of cancer. Interestingly, differential expression of these genes was observed within the different cell lines and when comparing IL27 to IFN-γ. In coculture experiments of hepatocellular carcinoma (HCC) cells with peripheral blood mononuclear cells, pre-treatment of the HCC cells with IL27 resulted in lowered IL2 production by anti-CD3/-CD28 activated T-lymphocytes. Addition of anti-PD-L1 antibody, however, restored IL2 secretion. The levels of other TH 1 cytokines were also enhanced or restored upon administration of anti-PD-L1. In addition, we show that the suppression of IL27 signaling by IL6-type cytokine pre-stimulation-mimicking a situation occurring, for example, in IL6-secreting tumors or in tumor inflammation-induced cachexia-can be antagonized by antibodies against IL6-type cytokines or their receptors. Therapeutically, the antitumor effects of IL27 (mediated, e.g., by increased antigen presentation) might thus be increased by combining IL27 with blocking antibodies against PD-L1 or/and IL6-type cytokines.
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Affiliation(s)
- Catherine Rolvering
- University of Luxembourg, Life Sciences Research Unit-Signal Transduction Laboratory, Belvaux, Luxembourg
| | - Andreas D Zimmer
- University of Luxembourg, Life Sciences Research Unit-Signal Transduction Laboratory, Belvaux, Luxembourg
| | - Aurélien Ginolhac
- University of Luxembourg, Life Sciences Research Unit-Bioinformatics Core Facility, Belvaux, Luxembourg
| | - Christiane Margue
- University of Luxembourg, Life Sciences Research Unit-Signal Transduction Laboratory, Belvaux, Luxembourg
| | - Mélanie Kirchmeyer
- University of Luxembourg, Life Sciences Research Unit-Signal Transduction Laboratory, Belvaux, Luxembourg
| | - Florence Servais
- University of Luxembourg, Life Sciences Research Unit-Signal Transduction Laboratory, Belvaux, Luxembourg
| | - Heike M Hermanns
- University Hospital Würzburg, Medical Clinic II, Division of Hepatology, Würzburg, Germany
| | - Sabine Hergovits
- University Hospital Würzburg, Medical Clinic II, Division of Hepatology, Würzburg, Germany
| | - Petr V Nazarov
- Proteome and Genome Research Unit, Department of Oncology, Luxembourg Institute of Health, Luxembourg, Luxembourg
| | - Nathalie Nicot
- Proteome and Genome Research Unit, Department of Oncology, Luxembourg Institute of Health, Luxembourg, Luxembourg
| | - Stephanie Kreis
- University of Luxembourg, Life Sciences Research Unit-Signal Transduction Laboratory, Belvaux, Luxembourg
| | - Serge Haan
- University of Luxembourg, Life Sciences Research Unit-Molecular Disease Mechanisms Laboratory, Belvaux, Luxembourg
| | - Iris Behrmann
- University of Luxembourg, Life Sciences Research Unit-Signal Transduction Laboratory, Belvaux, Luxembourg
| | - Claude Haan
- University of Luxembourg, Life Sciences Research Unit-Signal Transduction Laboratory, Belvaux, Luxembourg
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18
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do Carmo JM, da Silva AA, Freeman JN, Wang Z, Moak SP, Hankins MW, Drummond HA, Hall JE. Neuronal Suppressor of Cytokine Signaling 3: Role in Modulating Chronic Metabolic and Cardiovascular Effects of Leptin. Hypertension 2018; 71:1248-1257. [PMID: 29686012 DOI: 10.1161/hypertensionaha.118.11127] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2018] [Revised: 03/06/2018] [Accepted: 03/19/2018] [Indexed: 12/21/2022]
Abstract
We determined whether deficiency of neuronal SOCS3 (suppressor of cytokine signaling 3)-a potential negative regulator of leptin signaling-amplifies the chronic effects of leptin on food intake, energy expenditure, glucose, and blood pressure (BP) and protects against adverse cardiometabolic effects of obesity. BP and heart rate were recorded by telemetry, and oxygen consumption (VO2) was monitored in 22-week-old mice with nervous system SOCS3 deficiency (SOCS3-Nestin-Cre) and control mice (SOCS3flox/flox) fed normal or high-fat-high-fructose diet from 6 to 22 weeks of age. Compared with controls, SOCS3-Nestin-Cre mice had lower plasma glucose (124±7 versus 146±10 mg/dL), consumed less food (3.0±0.4 versus 3.6±0.2 g/d), and had similar VO2 (77±6 versus 73±3 mL/kg per minute) and BP (103±3 versus 107±3 mm Hg) but higher heart rate (666±15 versus 602±17 bpm). In mice fed the normal diet, leptin infusion for 7 days caused similar reductions in food intake (2.3±0.1 versus 2.4±0.2 g) but greater increases in BP (15±3 versus 7±2 mm Hg) in SOCS3-Nestin-Cre compared with controls. Leptin reduced blood glucose concentrations in both groups. Male or female SOCS3-Nestin-Cre fed high-fat-high-fructose diet exhibited less weight gain, body fat, and liver steatosis and greater energy expenditure and heart rate compared with controls. Female SOCS3-Nestin-Cre mice fed high-fat-high-fructose diet had higher BP compared with controls. Thus, neuronal SOCS3 seems to play an important role in cardiometabolic regulation because neuronal SOCS3 deficiency reduced body weight and food intake while amplifying leptin's effects on appetite and BP and attenuating the adverse metabolic effects of high-fat-high-fructose diet.
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Affiliation(s)
- Jussara M do Carmo
- From the Department of Physiology and Biophysics, Mississippi Center for Obesity Research, Cardiovascular-Renal Research Center, University of Mississippi Medical Center, Jackson (J.M.d.C., A.A.d.S., J.N.F., Z.W., S.P.M., M.W.H., H.A.D., J.E.H.)
| | - Alexandre A da Silva
- From the Department of Physiology and Biophysics, Mississippi Center for Obesity Research, Cardiovascular-Renal Research Center, University of Mississippi Medical Center, Jackson (J.M.d.C., A.A.d.S., J.N.F., Z.W., S.P.M., M.W.H., H.A.D., J.E.H.).,Faculdade de Medicina, Departamento de Fisiologia, Barão de Mauá University Center, Ribeirão Preto, São Paulo, Brazil (A.A.d.S.).,and Faculdade de Medicina, Departamento de Fisiologia, Universidade Estadual de Minas Gerais, Passos, Brazil (A.A.d.S.)
| | - John Nathan Freeman
- From the Department of Physiology and Biophysics, Mississippi Center for Obesity Research, Cardiovascular-Renal Research Center, University of Mississippi Medical Center, Jackson (J.M.d.C., A.A.d.S., J.N.F., Z.W., S.P.M., M.W.H., H.A.D., J.E.H.)
| | - Zhen Wang
- From the Department of Physiology and Biophysics, Mississippi Center for Obesity Research, Cardiovascular-Renal Research Center, University of Mississippi Medical Center, Jackson (J.M.d.C., A.A.d.S., J.N.F., Z.W., S.P.M., M.W.H., H.A.D., J.E.H.)
| | - Sydney P Moak
- From the Department of Physiology and Biophysics, Mississippi Center for Obesity Research, Cardiovascular-Renal Research Center, University of Mississippi Medical Center, Jackson (J.M.d.C., A.A.d.S., J.N.F., Z.W., S.P.M., M.W.H., H.A.D., J.E.H.)
| | - Michael W Hankins
- From the Department of Physiology and Biophysics, Mississippi Center for Obesity Research, Cardiovascular-Renal Research Center, University of Mississippi Medical Center, Jackson (J.M.d.C., A.A.d.S., J.N.F., Z.W., S.P.M., M.W.H., H.A.D., J.E.H.)
| | - Heather A Drummond
- From the Department of Physiology and Biophysics, Mississippi Center for Obesity Research, Cardiovascular-Renal Research Center, University of Mississippi Medical Center, Jackson (J.M.d.C., A.A.d.S., J.N.F., Z.W., S.P.M., M.W.H., H.A.D., J.E.H.)
| | - John E Hall
- From the Department of Physiology and Biophysics, Mississippi Center for Obesity Research, Cardiovascular-Renal Research Center, University of Mississippi Medical Center, Jackson (J.M.d.C., A.A.d.S., J.N.F., Z.W., S.P.M., M.W.H., H.A.D., J.E.H.)
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19
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Mancuso P, Curtis JL, Freeman CM, Peters-Golden M, Weinberg JB, Myers MG. Ablation of the leptin receptor in myeloid cells impairs pulmonary clearance of Streptococcus pneumoniae and alveolar macrophage bactericidal function. Am J Physiol Lung Cell Mol Physiol 2018; 315:L78-L86. [PMID: 29565180 DOI: 10.1152/ajplung.00447.2017] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Leptin is a pleiotropic hormone produced by white adipose tissue that regulates appetite and many physiological functions, including the immune response to infection. Genetic leptin deficiency in humans and mice impairs host defenses against respiratory tract infections. Since leptin deficiency is associated with obesity and other metabolic abnormalities, we generated mice that lack the leptin receptor (LepRb) in cells of the myeloid linage (LysM-LepRb-KO) to evaluate its impact in lean metabolically normal mice in a murine model of pneumococcal pneumonia. We observed higher lung and spleen bacterial burdens in LysM-LepRb-KO mice following an intratracheal challenge with Streptococcus pneumoniae. Although numbers of leukocytes recovered from bronchoalveolar lavage fluid did not differ between groups, we did observe higher levels of pulmonary IL-13 and TNFα in LysM-LepRb-KO mice 48 h post infection. Phagocytosis and killing of ingested S. pneumoniae were also impaired in alveolar macrophages (AMs) from LysM-LepRb-KO mice in vitro and were associated with reduced LTB4 and enhanced PGE2 synthesis in vitro. Pretreatment of AMs with LTB4 and the cyclooxygenase inhibitor, indomethacin, restored phagocytosis but not bacterial killing in vitro. These results confirm our previous observations in leptin-deficient ( ob/ob) and fasted mice and demonstrate that decreased leptin action, as opposed to metabolic irregularities associated with obesity or starvation, is responsible for the defective host defense against pneumococcal pneumonia. They also provide novel targets for therapeutic intervention in humans with bacterial pneumonia.
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Affiliation(s)
- Peter Mancuso
- Department of Environmental Health Sciences, University of Michigan , Ann Arbor, Michigan.,Department of Nutritional Sciences, School of Public Health, University of Michigan , Ann Arbor, Michigan.,Graduate Program in Immunology, University of Michigan , Ann Arbor, Michigan
| | - Jeffrey L Curtis
- Graduate Program in Immunology, University of Michigan , Ann Arbor, Michigan.,Division of Pulmonary and Critical Care Medicine, University of Michigan , Ann Arbor, Michigan.,Veterans Affairs, Ann Arbor Healthcare System, Ann Arbor, Michigan
| | - Christine M Freeman
- Graduate Program in Immunology, University of Michigan , Ann Arbor, Michigan.,Division of Pulmonary and Critical Care Medicine, University of Michigan , Ann Arbor, Michigan.,Veterans Affairs, Ann Arbor Healthcare System, Ann Arbor, Michigan
| | - Marc Peters-Golden
- Graduate Program in Immunology, University of Michigan , Ann Arbor, Michigan.,Division of Pulmonary and Critical Care Medicine, University of Michigan , Ann Arbor, Michigan
| | - Jason B Weinberg
- Department of Pediatrics and Communicable Diseases, University of Michigan , Ann Arbor, Michigan.,Department of Microbiology and Immunology, University of Michigan , Ann Arbor, Michigan
| | - Martin G Myers
- Department of Integrative and Molecular Physiology, University of Michigan , Ann Arbor, Michigan
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20
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Jiang M, Chen J, Zhang W, Zhang R, Ye Y, Liu P, Yu W, Wei F, Ren X, Yu J. Interleukin-6 Trans-Signaling Pathway Promotes Immunosuppressive Myeloid-Derived Suppressor Cells via Suppression of Suppressor of Cytokine Signaling 3 in Breast Cancer. Front Immunol 2017; 8:1840. [PMID: 29326716 PMCID: PMC5736866 DOI: 10.3389/fimmu.2017.01840] [Citation(s) in RCA: 77] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2017] [Accepted: 12/05/2017] [Indexed: 12/28/2022] Open
Abstract
Interleukin-6 (IL-6) has been reported to stimulate myeloid-derived suppressor cells (MDSCs) in multiple cancers, but the molecular events involved in this process are not completely understood. We previously found that cancer-derived IL-6 induces T cell suppression of MDSCs in vitro via the activation of STAT3/IDO signaling pathway. In this study, we aimed to elucidate the underlying mechanisms. We found that in primary breast cancer tissues, cancer-derived IL-6 was positively correlated with infiltration of MDSCs in situ, which was accompanied by more aggressive tumor phenotypes and worse clinical outcomes. In vitro IL-6 stimulated the amplification of MDSCs and promoted their T cell suppression ability, which were fully inhibited by an IL-6-specific blocking antibody. Our results demonstrate that IL-6-dependent suppressor of cytokine signaling 3 (SOCS3) suppression in MDSCs induced phosphorylation of the JAK1, JAK2, TYK2, STAT1, and STAT3 proteins, which was correlated with T cell suppression of MDSCs in vitro. Therefore, dysfunction in the SOCS feedback loop promoted long-term activation of the JAK/STAT signaling pathway and predominantly contributed to IL-6-mediated effects on MDSCs. Furthermore, IL-6-induced inhibition of SOCS3 and activation of the JAK/STAT pathway was correlated with an elevated expression of IL-6 receptor α (CD126), in which the soluble CD126-mediated IL-6 trans-signaling pathway significantly regulated IL-6-mediated effects on MDSCs. Finally, IL-6-induced SOCS3 dysfunction and sustained activation of the JAK/STAT signaling pathway promoted the amplification and immunosuppressive function of breast cancer MDSCs in vitro and in vivo, and thus blocking the IL-6 signaling pathway is a promising therapeutic strategy for eliminating and inhibiting MDSCs to improve prognosis.
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Affiliation(s)
- Mengmeng Jiang
- Cancer Molecular Diagnostics Core, Tianjin Medical University Cancer Institute and Hospital, National Clinical Research Center for Cancer, Key Laboratory of Cancer Prevention and Therapy, Tianjin's Clinical Research Center for Cancer, Tianjin, China.,Department of Immunology, Tianjin Medical University Cancer Institute and Hospital, National Clinical Research Center for Cancer, Key Laboratory of Cancer Immunology and Biotherapy, Tianjin's Clinical Research Center for Cancer, Tianjin, China
| | - Jieying Chen
- Department of Urology, Tianjin Medical University General Hospital, Tianjin, China
| | - Wenwen Zhang
- Cancer Molecular Diagnostics Core, Tianjin Medical University Cancer Institute and Hospital, National Clinical Research Center for Cancer, Key Laboratory of Cancer Prevention and Therapy, Tianjin's Clinical Research Center for Cancer, Tianjin, China.,Department of Immunology, Tianjin Medical University Cancer Institute and Hospital, National Clinical Research Center for Cancer, Key Laboratory of Cancer Immunology and Biotherapy, Tianjin's Clinical Research Center for Cancer, Tianjin, China
| | - Rui Zhang
- Cancer Molecular Diagnostics Core, Tianjin Medical University Cancer Institute and Hospital, National Clinical Research Center for Cancer, Key Laboratory of Cancer Prevention and Therapy, Tianjin's Clinical Research Center for Cancer, Tianjin, China
| | - Yingnan Ye
- Cancer Molecular Diagnostics Core, Tianjin Medical University Cancer Institute and Hospital, National Clinical Research Center for Cancer, Key Laboratory of Cancer Prevention and Therapy, Tianjin's Clinical Research Center for Cancer, Tianjin, China
| | - Pengpeng Liu
- Cancer Molecular Diagnostics Core, Tianjin Medical University Cancer Institute and Hospital, National Clinical Research Center for Cancer, Key Laboratory of Cancer Prevention and Therapy, Tianjin's Clinical Research Center for Cancer, Tianjin, China
| | - Wenwen Yu
- Department of Immunology, Tianjin Medical University Cancer Institute and Hospital, National Clinical Research Center for Cancer, Key Laboratory of Cancer Immunology and Biotherapy, Tianjin's Clinical Research Center for Cancer, Tianjin, China
| | - Feng Wei
- Department of Immunology, Tianjin Medical University Cancer Institute and Hospital, National Clinical Research Center for Cancer, Key Laboratory of Cancer Immunology and Biotherapy, Tianjin's Clinical Research Center for Cancer, Tianjin, China
| | - Xiubao Ren
- Department of Immunology, Tianjin Medical University Cancer Institute and Hospital, National Clinical Research Center for Cancer, Key Laboratory of Cancer Immunology and Biotherapy, Tianjin's Clinical Research Center for Cancer, Tianjin, China
| | - Jinpu Yu
- Cancer Molecular Diagnostics Core, Tianjin Medical University Cancer Institute and Hospital, National Clinical Research Center for Cancer, Key Laboratory of Cancer Prevention and Therapy, Tianjin's Clinical Research Center for Cancer, Tianjin, China.,Department of Immunology, Tianjin Medical University Cancer Institute and Hospital, National Clinical Research Center for Cancer, Key Laboratory of Cancer Immunology and Biotherapy, Tianjin's Clinical Research Center for Cancer, Tianjin, China
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21
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Dodd GT, Tiganis T. Insulin action in the brain: Roles in energy and glucose homeostasis. J Neuroendocrinol 2017; 29. [PMID: 28758251 DOI: 10.1111/jne.12513] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/19/2017] [Revised: 07/05/2017] [Accepted: 07/26/2017] [Indexed: 12/14/2022]
Abstract
A growing body of evidence from research in rodents and humans has identified insulin as an important neuoregulatory peptide in the brain, where it coordinates diverse aspects of energy balance and peripheral glucose homeostasis. This review discusses where and how insulin interacts within the brain and evaluates the physiological and pathophysiological consequences of central insulin signalling in metabolism, obesity and type 2 diabetes.
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Affiliation(s)
- G T Dodd
- Metabolic Disease and Obesity Program, Monash Biomedicine Discovery Institute and Department of Biochemistry and Molecular Biology, Monash University, Melbourne, VIC, Australia
| | - T Tiganis
- Metabolic Disease and Obesity Program, Monash Biomedicine Discovery Institute and Department of Biochemistry and Molecular Biology, Monash University, Melbourne, VIC, Australia
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22
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Compound A influences gene regulation of the Dexamethasone-activated glucocorticoid receptor by alternative cofactor recruitment. Sci Rep 2017; 7:8063. [PMID: 28808239 PMCID: PMC5556032 DOI: 10.1038/s41598-017-07941-y] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2017] [Accepted: 07/03/2017] [Indexed: 01/12/2023] Open
Abstract
The glucocorticoid receptor (GR) is a transcription factor of which the underlying gene regulatory mechanisms are complex and incompletely understood. The non-steroidal anti-inflammatory Compound A (CpdA), a selective GR modulating compound in various cell models, has been shown to favour GR-mediated gene repression but not GR-mediated gene activation. Shifting balances towards only a particular subset of GR gene regulatory events may be of benefit in the treatment of inflammatory diseases. We present evidence to support that the combination of CpdA with Dexamethasone (DEX), a classic steroidal GR ligand, can shape GR function towards a unique gene regulatory profile in a cell type-dependent manner. The molecular basis hereof is a changed GR phosphorylation status concomitant with a change in the GR cofactor recruitment profile. We subsequently identified and confirmed the orphan nuclear receptor SHP as a coregulator that is specifically enriched at GR when CpdA and DEX are combined. Combining CpdA with DEX not only leads to stronger suppression of pro-inflammatory gene expression, but also enhanced anti-inflammatory GR target gene expression in epithelial cells, making ligand combination strategies in future a potentially attractive alternative manner of skewing and fine-tuning GR effects towards an improved therapeutic benefit.
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23
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Xu T, Xie W, Ma Y, Zhou S, Zhang L, Chen J, Cai M, Sun R, Zhang P, Yu S, Xu Z, Jiang W, Wu M. Leptin/OB-R pathway promotes IL-4 secretion from B lymphocytes and induces salivary gland epithelial cell apoptosis in Sjögren's syndrome. Oncotarget 2017; 8:63417-63429. [PMID: 28969001 PMCID: PMC5609933 DOI: 10.18632/oncotarget.18823] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2017] [Accepted: 06/01/2017] [Indexed: 12/16/2022] Open
Abstract
Sjögren's syndrome (SjS) is a chronic autoimmune epithelitis in which cell apoptosis promotes the formation of inflammatory lesions. We used immunohistochemistry and TUNEL to assay B cell infiltration and apoptosis in salivary gland tissue from 16-week-old NOD/LtJ mice with SjS. In co-cultures of primary salivary glandepithelial cells (SGECs) and spleen B cells, we assessed SGEC viability and apoptosis using CCK8 assays and flow cytometry. ELISAs were employed to assess cytokine levels in culture medium. Leptin protein, leptin receptor (OB-R), pro- and anti-apoptotic proteins, and Jak2/Stat3/ERK signaling molecules were analyzed using western blotting. B cell infiltration and salivary gland apoptosis were increased in salivary tissue from mice with SjS. Leptin treatment had no effect on cell viability or apoptosis among B cells and primary SGECs. B cell and SGEC co-culture systems showed that leptin increased apoptosis induced by B lymphocytes, reduced SGEC cell viability, and promoted IL-4 secretion from B cells. This suggests Leptin/OB-R signaling stimulates B cells-induced SGEC apoptosis via IL-4 secretion and OB-R-Jak2-Stat3 activation.
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Affiliation(s)
- Ting Xu
- Department of Rheumatology and Immunology, The Third Affiliated Hospital of Soochow University, Jiangsu, Changzhou 213003, China
| | - Wen Xie
- Department of Rheumatology and Immunology, The Third Affiliated Hospital of Soochow University, Jiangsu, Changzhou 213003, China
| | - Yingchun Ma
- Department of Rheumatology and Immunology, The Third Affiliated Hospital of Soochow University, Jiangsu, Changzhou 213003, China
| | - Shiliang Zhou
- Department of Rheumatology and Immunology, The Third Affiliated Hospital of Soochow University, Jiangsu, Changzhou 213003, China
| | - Lu Zhang
- Department of Rheumatology and Immunology, The Third Affiliated Hospital of Soochow University, Jiangsu, Changzhou 213003, China
| | - Jinyun Chen
- Department of Rheumatology and Immunology, The Third Affiliated Hospital of Soochow University, Jiangsu, Changzhou 213003, China
| | - Mingyuan Cai
- Department of Rheumatology and Immunology, The Third Affiliated Hospital of Soochow University, Jiangsu, Changzhou 213003, China
| | - Rurong Sun
- Department of Rheumatology and Immunology, The Third Affiliated Hospital of Soochow University, Jiangsu, Changzhou 213003, China
| | - Peirong Zhang
- Department of Rheumatology and Immunology, The Third Affiliated Hospital of Soochow University, Jiangsu, Changzhou 213003, China
| | - Shaobo Yu
- Department of Rheumatology and Immunology, The Third Affiliated Hospital of Soochow University, Jiangsu, Changzhou 213003, China
| | - Zheng Xu
- Department of Rheumatology and Immunology, The Third Affiliated Hospital of Soochow University, Jiangsu, Changzhou 213003, China
| | - Wanlan Jiang
- Department of Rheumatology and Immunology, The Third Affiliated Hospital of Soochow University, Jiangsu, Changzhou 213003, China
| | - Min Wu
- Department of Rheumatology and Immunology, The Third Affiliated Hospital of Soochow University, Jiangsu, Changzhou 213003, China
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24
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Wauman J, Zabeau L, Tavernier J. The Leptin Receptor Complex: Heavier Than Expected? Front Endocrinol (Lausanne) 2017; 8:30. [PMID: 28270795 PMCID: PMC5318964 DOI: 10.3389/fendo.2017.00030] [Citation(s) in RCA: 103] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/01/2016] [Accepted: 02/01/2017] [Indexed: 12/31/2022] Open
Abstract
Under normal physiological conditions, leptin and the leptin receptor (ObR) regulate the body weight by balancing food intake and energy expenditure. However, this adipocyte-derived hormone also directs peripheral processes, including immunity, reproduction, and bone metabolism. Leptin, therefore, can act as a metabolic switch connecting the body's nutritional status to high energy consuming processes. We provide an extensive overview of current structural insights on the leptin-ObR interface and ObR activation, coupling to signaling pathways and their negative regulation, and leptin functioning under normal and pathophysiological conditions (obesity, autoimmunity, cancer, … ). We also discuss possible cross-talk with other receptor systems on the receptor (extracellular) and signaling cascade (intracellular) levels.
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Affiliation(s)
- Joris Wauman
- Cytokine Receptor Laboratory, Faculty of Medicine and Health Sciences, Department of Biochemistry, Ghent University, Ghent, Belgium
- VIB Medical Biotechnology Center, VIB, Ghent, Belgium
| | - Lennart Zabeau
- Cytokine Receptor Laboratory, Faculty of Medicine and Health Sciences, Department of Biochemistry, Ghent University, Ghent, Belgium
- VIB Medical Biotechnology Center, VIB, Ghent, Belgium
| | - Jan Tavernier
- Cytokine Receptor Laboratory, Faculty of Medicine and Health Sciences, Department of Biochemistry, Ghent University, Ghent, Belgium
- VIB Medical Biotechnology Center, VIB, Ghent, Belgium
- *Correspondence: Jan Tavernier,
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25
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Rolvering C, Zimmer AD, Kozar I, Hermanns HM, Letellier E, Vallar L, Nazarov PV, Nicot N, Ginolhac A, Haan S, Behrmann I, Haan C. Crosstalk between different family members: IL27 recapitulates IFNγ responses in HCC cells, but is inhibited by IL6-type cytokines. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2016; 1864:516-526. [PMID: 27939431 DOI: 10.1016/j.bbamcr.2016.12.006] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/23/2016] [Revised: 12/02/2016] [Accepted: 12/07/2016] [Indexed: 01/10/2023]
Abstract
Interleukin-27 (IL27) is a type-I-cytokine of the IL6/IL12 family predominantly secreted by activated macrophages and dendritic cells. In the liver, IL27 expression was observed to be upregulated in patients with hepatitis B, and sera of hepatocellular carcinoma (HCC) patients contain significantly elevated levels of IL27 compared to healthy controls or patients with hepatitis and/or liver cirrhosis. In this study, we show that IL27 induces STAT1 and STAT3 phosphorylation in 5 HCC lines and 3 different types of non-transformed liver cells. We were especially interested in the relevance of the IL27-induced STAT3 activation in liver cells. Thus, we compared the IL27 responses with those induced by IFNγ (STAT1-dominated response) or IL6-type cytokines (IL6, hyper-IL6 (hy-IL6) or OSM) (STAT3-dominated response) by microarray analysis and find that in HCC cells, IL27 induces an IFNγ-like, STAT1-dependent transcriptional response, but we do not find an effective STAT3-dependent response. Validation experiments corroborate the finding from the microarray evaluation. Interestingly, the availability of STAT1 seems critical in the shaping of the IL27 response, as the siRNA knock-down of STAT1 revealed the ability of IL27 to induce the acute-phase protein γ-fibrinogen, a typical IL6 family characteristic. Moreover, we describe a crosstalk between the signaling of IL6-type cytokines and IL27: responses to the gp130-engaging cytokine IL27 (but not those to IFNs) can be inhibited by IL6-type cytokine pre-stimulation, likely by a SOCS3-mediated mechanism. Thus, IL27 recapitulates IFNγ responses in liver cells, but differs from IFNγ by its sensitivity to SOCS3 inhibition.
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Affiliation(s)
- Catherine Rolvering
- University of Luxembourg, Life Sciences Research Unit - Signal Transduction Laboratory, 6, Avenue du Swing, L4367 Belvaux, Luxembourg.
| | - Andreas D Zimmer
- University of Luxembourg, Life Sciences Research Unit - Signal Transduction Laboratory, 6, Avenue du Swing, L4367 Belvaux, Luxembourg.
| | - Ines Kozar
- University of Luxembourg, Life Sciences Research Unit - Signal Transduction Laboratory, 6, Avenue du Swing, L4367 Belvaux, Luxembourg.
| | - Heike M Hermanns
- University Hospital Würzburg, Medical Clinic II, Division of Hepatology, Grombühlstr. 12, D-97080 Würzburg, Germany.
| | - Elisabeth Letellier
- University of Luxembourg, Life Sciences Research Unit - Molecular Disease Mechanisms Laboratory, 6, Avenue du Swing, L4367 Belvaux, Luxembourg.
| | - Laurent Vallar
- Genomics Research Laboratory, Dept. of Oncology, Luxembourg Institute of Health, 84 Val Fleuri, L1526 Luxembourg, Luxembourg.
| | - Petr V Nazarov
- Genomics Research Laboratory, Dept. of Oncology, Luxembourg Institute of Health, 84 Val Fleuri, L1526 Luxembourg, Luxembourg.
| | - Nathalie Nicot
- Genomics Research Laboratory, Dept. of Oncology, Luxembourg Institute of Health, 84 Val Fleuri, L1526 Luxembourg, Luxembourg.
| | - Aurélien Ginolhac
- University of Luxembourg, Life Sciences Research Unit - Bioinformatics Core Facility, 6, Avenue du Swing, L4367 Belvaux, Luxembourg.
| | - Serge Haan
- University of Luxembourg, Life Sciences Research Unit - Molecular Disease Mechanisms Laboratory, 6, Avenue du Swing, L4367 Belvaux, Luxembourg.
| | - Iris Behrmann
- University of Luxembourg, Life Sciences Research Unit - Signal Transduction Laboratory, 6, Avenue du Swing, L4367 Belvaux, Luxembourg.
| | - Claude Haan
- University of Luxembourg, Life Sciences Research Unit - Signal Transduction Laboratory, 6, Avenue du Swing, L4367 Belvaux, Luxembourg.
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26
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Eyckerman S, Impens F, Van Quickelberghe E, Samyn N, Vandemoortele G, De Sutter D, Tavernier J, Gevaert K. Intelligent Mixing of Proteomes for Elimination of False Positives in Affinity Purification-Mass Spectrometry. J Proteome Res 2016; 15:3929-3937. [PMID: 27640904 DOI: 10.1021/acs.jproteome.6b00517] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Protein complexes are essential in all organizational and functional aspects of the cell. Different strategies currently exist for analyzing such protein complexes by mass spectrometry, including affinity purification (AP-MS) and proximal labeling-based strategies. However, the high sensitivity of current mass spectrometers typically results in extensive protein lists mainly consisting of nonspecifically copurified proteins. Finding the true positive interactors in these lists remains highly challenging. Here, we report a powerful design based on differential labeling with stable isotopes combined with nonequal mixing of control and experimental samples to discover bona fide interaction partners in AP-MS experiments. We apply this intelligent mixing of proteomes (iMixPro) concept to overexpression experiments for RAF1, RNF41, and TANK and also to engineered cell lines expressing epitope-tagged endogenous PTPN14, JIP3, and IQGAP1. For all baits, we confirmed known interactions and found a number of novel interactions. The results for RNF41 and TANK were compared to a classical affinity purification experiment, which demonstrated the efficiency and specificity of the iMixPro approach.
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Affiliation(s)
- Sven Eyckerman
- VIB Medical Biotechnology Center , Albert Baertsoenkaai 3, B-9000 Ghent, Belgium.,Department of Biochemistry, Ghent University , Albert Baertsoenkaai 3, B-9000 Ghent, Belgium
| | - Francis Impens
- VIB Medical Biotechnology Center , Albert Baertsoenkaai 3, B-9000 Ghent, Belgium.,Department of Biochemistry, Ghent University , Albert Baertsoenkaai 3, B-9000 Ghent, Belgium.,VIB Proteomics Expertise Center , Albert Baertsoenkaai 3, B-9000 Ghent, Belgium
| | - Emmy Van Quickelberghe
- VIB Medical Biotechnology Center , Albert Baertsoenkaai 3, B-9000 Ghent, Belgium.,Department of Biochemistry, Ghent University , Albert Baertsoenkaai 3, B-9000 Ghent, Belgium
| | - Noortje Samyn
- VIB Medical Biotechnology Center , Albert Baertsoenkaai 3, B-9000 Ghent, Belgium.,Department of Biochemistry, Ghent University , Albert Baertsoenkaai 3, B-9000 Ghent, Belgium
| | - Giel Vandemoortele
- VIB Medical Biotechnology Center , Albert Baertsoenkaai 3, B-9000 Ghent, Belgium.,Department of Biochemistry, Ghent University , Albert Baertsoenkaai 3, B-9000 Ghent, Belgium
| | - Delphine De Sutter
- VIB Medical Biotechnology Center , Albert Baertsoenkaai 3, B-9000 Ghent, Belgium.,Department of Biochemistry, Ghent University , Albert Baertsoenkaai 3, B-9000 Ghent, Belgium
| | - Jan Tavernier
- VIB Medical Biotechnology Center , Albert Baertsoenkaai 3, B-9000 Ghent, Belgium.,Department of Biochemistry, Ghent University , Albert Baertsoenkaai 3, B-9000 Ghent, Belgium
| | - Kris Gevaert
- VIB Medical Biotechnology Center , Albert Baertsoenkaai 3, B-9000 Ghent, Belgium.,Department of Biochemistry, Ghent University , Albert Baertsoenkaai 3, B-9000 Ghent, Belgium
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27
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Vervliet T, Lemmens I, Vandermarliere E, Decrock E, Ivanova H, Monaco G, Sorrentino V, Kasri NN, Missiaen L, Martens L, De Smedt H, Leybaert L, Parys JB, Tavernier J, Bultynck G. Ryanodine receptors are targeted by anti-apoptotic Bcl-XL involving its BH4 domain and Lys87 from its BH3 domain. Sci Rep 2015; 5:9641. [PMID: 25872771 PMCID: PMC4397538 DOI: 10.1038/srep09641] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2014] [Accepted: 03/13/2015] [Indexed: 11/29/2022] Open
Abstract
Anti-apoptotic B-cell lymphoma 2 (Bcl-2) family members target several intracellular Ca(2+)-transport systems. Bcl-2, via its N-terminal Bcl-2 homology (BH) 4 domain, inhibits both inositol 1,4,5-trisphosphate receptors (IP3Rs) and ryanodine receptors (RyRs), while Bcl-XL, likely independently of its BH4 domain, sensitizes IP3Rs. It remains elusive whether Bcl-XL can also target and modulate RyRs. Here, Bcl-XL co-immunoprecipitated with RyR3 expressed in HEK293 cells. Mammalian protein-protein interaction trap (MAPPIT) and surface plasmon resonance (SPR) showed that Bcl-XL bound to the central domain of RyR3 via its BH4 domain, although to a lesser extent compared to the BH4 domain of Bcl-2. Consistent with the ability of the BH4 domain of Bcl-XL to bind to RyRs, loading the BH4-Bcl-XL peptide into RyR3-overexpressing HEK293 cells or in rat hippocampal neurons suppressed RyR-mediated Ca(2+) release. In silico superposition of the 3D-structures of Bcl-2 and Bcl-XL indicated that Lys87 of the BH3 domain of Bcl-XL could be important for interacting with RyRs. In contrast to Bcl-XL, the Bcl-XL(K87D) mutant displayed lower binding affinity for RyR3 and a reduced inhibition of RyR-mediated Ca(2+) release. These data suggest that Bcl-XL binds to RyR channels via its BH4 domain, but also its BH3 domain, more specific Lys87, contributes to the interaction.
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Affiliation(s)
- Tim Vervliet
- KU Leuven, Laboratory of Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine, B-3000 Leuven, Belgium
| | - Irma Lemmens
- University of Gent, Cytokine Receptor Lab, VIB Department of Medical Protein Research, B-9000 Gent, Belgium
| | - Elien Vandermarliere
- University of Gent, Computational Omics and Systems Biology Group, VIB Department of Medical Protein Research, B-9000 Gent, Belgium
| | - Elke Decrock
- University of Gent, Physiology Group, Department of Basic Medical Sciences, B-9000 Gent, Belgium
| | - Hristina Ivanova
- KU Leuven, Laboratory of Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine, B-3000 Leuven, Belgium
| | - Giovanni Monaco
- KU Leuven, Laboratory of Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine, B-3000 Leuven, Belgium
| | - Vincenzo Sorrentino
- University of Siena, Molecular Medicine Section, Department of Molecular and Developmental Medicine, and Interuniversitary Institute of Myology, 53100 Siena, Italy
| | - Nael Nadif Kasri
- Radboud University Medical Center, Donders Institute for Brain, Cognition and Behaviour, Department of Cognitive Neuroscience, Department of Human Genetics, 6500HB Nijmegen, The Netherlands
| | - Ludwig Missiaen
- KU Leuven, Laboratory of Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine, B-3000 Leuven, Belgium
| | - Lennart Martens
- University of Gent, Computational Omics and Systems Biology Group, VIB Department of Medical Protein Research, B-9000 Gent, Belgium
| | - Humbert De Smedt
- KU Leuven, Laboratory of Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine, B-3000 Leuven, Belgium
| | - Luc Leybaert
- University of Gent, Physiology Group, Department of Basic Medical Sciences, B-9000 Gent, Belgium
| | - Jan B. Parys
- KU Leuven, Laboratory of Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine, B-3000 Leuven, Belgium
| | - Jan Tavernier
- University of Gent, Cytokine Receptor Lab, VIB Department of Medical Protein Research, B-9000 Gent, Belgium
| | - Geert Bultynck
- KU Leuven, Laboratory of Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine, B-3000 Leuven, Belgium
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28
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Ghantous CM, Azrak Z, Hanache S, Abou-Kheir W, Zeidan A. Differential Role of Leptin and Adiponectin in Cardiovascular System. Int J Endocrinol 2015; 2015:534320. [PMID: 26064110 PMCID: PMC4433709 DOI: 10.1155/2015/534320] [Citation(s) in RCA: 123] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/07/2014] [Accepted: 04/23/2015] [Indexed: 02/07/2023] Open
Abstract
Leptin and adiponectin are differentially expressed adipokines in obesity and cardiovascular diseases. Leptin levels are directly associated with adipose tissue mass, while adiponectin levels are downregulated in obesity. Although significantly produced by adipocytes, leptin is also produced by vascular smooth muscle cells and cardiomyocytes. Plasma leptin concentrations are elevated in cases of cardiovascular diseases, such as hypertension, congestive heart failure, and myocardial infarction. As for the event of left ventricular hypertrophy, researchers have been stirring controversy about the role of leptin in this form of cardiac remodeling. In this review, we discuss how leptin has been shown to play an antihypertrophic role in the development of left ventricular hypertrophy through in vitro experiments, population-based cross-sectional studies, and longitudinal cohort studies. Conversely, we also examine how leptin may actually promote left ventricular hypertrophy using in vitro analysis and human-based univariate and multiple linear stepwise regression analysis. On the other hand, as opposed to leptin's generally detrimental effects on the cardiovascular system, adiponectin is a cardioprotective hormone that reduces left ventricular and vascular hypertrophy, oxidative stress, and inflammation. In this review, we also highlight adiponectin signaling and its protective actions on the cardiovascular system.
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Affiliation(s)
- C. M. Ghantous
- Department of Anatomy, Cell biology and Physiology, American University of Beirut, DTS-255, P.O. Box 11-0236, Beirut 1107-2020, Lebanon
| | - Z. Azrak
- Department of Pharmacology and Toxicology, American University of Beirut, DTS-255, P.O. Box 11-0236, Beirut 1107-2020, Lebanon
| | - S. Hanache
- Department of Anatomy, Cell biology and Physiology, American University of Beirut, DTS-255, P.O. Box 11-0236, Beirut 1107-2020, Lebanon
| | - W. Abou-Kheir
- Department of Anatomy, Cell biology and Physiology, American University of Beirut, DTS-255, P.O. Box 11-0236, Beirut 1107-2020, Lebanon
| | - A. Zeidan
- Department of Anatomy, Cell biology and Physiology, American University of Beirut, DTS-255, P.O. Box 11-0236, Beirut 1107-2020, Lebanon
- *A. Zeidan:
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29
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Moharana K, Zabeau L, Peelman F, Ringler P, Stahlberg H, Tavernier J, Savvides S. Structural and Mechanistic Paradigm of Leptin Receptor Activation Revealed by Complexes with Wild-Type and Antagonist Leptins. Structure 2014; 22:866-77. [DOI: 10.1016/j.str.2014.04.012] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2013] [Revised: 04/17/2014] [Accepted: 04/24/2014] [Indexed: 12/18/2022]
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30
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Pan H, Guo J, Su Z. Advances in understanding the interrelations between leptin resistance and obesity. Physiol Behav 2014; 130:157-69. [PMID: 24726399 DOI: 10.1016/j.physbeh.2014.04.003] [Citation(s) in RCA: 122] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2013] [Revised: 03/07/2014] [Accepted: 04/02/2014] [Indexed: 02/09/2023]
Abstract
Obesity, which has developed into a global epidemic, is a risk factor in most chronic diseases and some forms of malignancy. The discovery of leptin in 1994 has opened a new field in obesity research. Currently, we know that leptin is the primary signal from energy stores and exerts negative feedback effects on energy intake. However, most individuals with diet-induced obesity (DIO) develop leptin resistance, which is characterized by elevated circulating leptin levels and decreased leptin sensitivity. To date, though various mechanisms have been proposed to explain leptin resistance, the exact mechanisms of leptin resistance in obesity are poorly understood. Consequently, it's an important issue worth discussing regarding what the exact interrelations between leptin resistance and obesity are. Here, we review the latest advancements in the molecular mechanisms of leptin resistance and the exact interrelations between leptin resistance, obesity, and obesity-related diseases, in order to supply new ideas for the study of obesity.
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Affiliation(s)
- Haitao Pan
- Key Research Center of Liver Regulation for Hyperlipidemia SATCM/Class III Laboratory of Metabolism SATCM, Guangdong TCM Key Laboratory for Metabolic Diseases, Guangdong Pharmaceutical University, Guangzhou, Guangdong, China
| | - Jiao Guo
- Key Research Center of Liver Regulation for Hyperlipidemia SATCM/Class III Laboratory of Metabolism SATCM, Guangdong TCM Key Laboratory for Metabolic Diseases, Guangdong Pharmaceutical University, Guangzhou, Guangdong, China.
| | - Zhengquan Su
- Key Research Center of Liver Regulation for Hyperlipidemia SATCM/Class III Laboratory of Metabolism SATCM, Guangdong TCM Key Laboratory for Metabolic Diseases, Guangdong Pharmaceutical University, Guangzhou, Guangdong, China.
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31
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Carow B, Rottenberg ME. SOCS3, a Major Regulator of Infection and Inflammation. Front Immunol 2014; 5:58. [PMID: 24600449 PMCID: PMC3928676 DOI: 10.3389/fimmu.2014.00058] [Citation(s) in RCA: 340] [Impact Index Per Article: 34.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2013] [Accepted: 01/31/2014] [Indexed: 12/18/2022] Open
Abstract
In this review, we describe the role of suppressor of cytokine signaling-3 (SOCS3) in modulating the outcome of infections and autoimmune diseases as well as the underlying mechanisms. SOCS3 regulates cytokine or hormone signaling usually preventing, but in some cases aggravating, a variety of diseases. A main role of SOCS3 results from its binding to both the JAK kinase and the cytokine receptor, which results in the inhibition of STAT3 activation. Available data also indicate that SOCS3 can regulate signaling via other STATs than STAT3 and also controls cellular pathways unrelated to STAT activation. SOCS3 might either act directly by hampering JAK activation or by mediating the ubiquitination and subsequent proteasome degradation of the cytokine/growth factor/hormone receptor. Inflammation and infection stimulate SOCS3 expression in different myeloid and lymphoid cell populations as well as in diverse non-hematopoietic cells. The accumulated data suggest a relevant program coordinated by SOCS3 in different cell populations, devoted to the control of immune homeostasis in physiological and pathological conditions such as infection and autoimmunity.
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Affiliation(s)
- Berit Carow
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet , Stockholm , Sweden
| | - Martin E Rottenberg
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet , Stockholm , Sweden
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32
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Beck IM, Drebert ZJ, Hoya-Arias R, Bahar AA, Devos M, Clarisse D, Desmet S, Bougarne N, Ruttens B, Gossye V, Denecker G, Lievens S, Bracke M, Tavernier J, Declercq W, Gevaert K, Vanden Berghe W, Haegeman G, De Bosscher K. Compound A, a selective glucocorticoid receptor modulator, enhances heat shock protein Hsp70 gene promoter activation. PLoS One 2013; 8:e69115. [PMID: 23935933 PMCID: PMC3728325 DOI: 10.1371/journal.pone.0069115] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2012] [Accepted: 06/06/2013] [Indexed: 12/24/2022] Open
Abstract
Compound A possesses glucocorticoid receptor (GR)-dependent anti-inflammatory properties. Just like classical GR ligands, Compound A can repress NF-κB-mediated gene expression. However, the monomeric Compound A-activated GR is unable to trigger glucocorticoid response element-regulated gene expression. The heat shock response potently activates heat shock factor 1 (HSF1), upregulates Hsp70, a known GR chaperone, and also modulates various aspects of inflammation. We found that the selective GR modulator Compound A and heat shock trigger similar cellular effects in A549 lung epithelial cells. With regard to their anti-inflammatory mechanism, heat shock and Compound A are both able to reduce TNF-stimulated IκBα degradation and NF-κB p65 nuclear translocation. We established an interaction between Compound A-activated GR and Hsp70, but remarkably, although the presence of the Hsp70 chaperone as such appears pivotal for the Compound A-mediated inflammatory gene repression, subsequent novel Hsp70 protein synthesis is uncoupled from an observed CpdA-induced Hsp70 mRNA upregulation and hence obsolete in mediating CpdA’s anti-inflammatory effect. The lack of a Compound A-induced increase in Hsp70 protein levels in A549 cells is not mediated by a rapid proteasomal degradation of Hsp70 or by a Compound A-induced general block on translation. Similar to heat shock, Compound A can upregulate transcription of Hsp70 genes in various cell lines and BALB/c mice. Interestingly, whereas Compound A-dependent Hsp70 promoter activation is GR-dependent but HSF1-independent, heat shock-induced Hsp70 expression alternatively occurs in a GR-independent and HSF1-dependent manner in A549 lung epithelial cells.
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Affiliation(s)
- Ilse M Beck
- Laboratory of Experimental Cancer Research (LECR), Department of Radiation Therapy & Experimental Cancer Research, Ghent University, Ghent, Belgium.
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A novel missense (M206K) STAT3 mutation in diffuse large B cell lymphoma deregulates STAT3 signaling. PLoS One 2013; 8:e67851. [PMID: 23861822 PMCID: PMC3701620 DOI: 10.1371/journal.pone.0067851] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2013] [Accepted: 05/22/2013] [Indexed: 01/17/2023] Open
Abstract
Persistent STAT3 activation has been found in activated B-cell like diffuse large B cell tumors (DLBCL). To investigate whether genetic mutations play a role in aberrant STAT3 signaling in DLBCL, we bi-directionally sequenced all 24 exons of the STAT3 gene in DLBCL tumors (n = 40). We identified 2 novel point mutations in 2 separate (2/40; 5%) patients at exon 7 and 24. Point mutation 2552G>A was a silent mutation in the stop codon. Another heterozygous mutation 857T>A encoded a methionine substitution by lysine at codon 206 (M206K) in the coiled-coil domain of STAT3. We performed site directed mutagenesis to mutate wild type (WT) STAT3α and STAT3β at codon 206 and constructed stable cell lines by lentiviral transfection of STAT3αWT, STAT3αM206K, STAT3βWT and STAT3βM206K plasmids. The mutation was found to increase STAT3 phosphorylation in STAT3α mutant cell lines with no effect on the STAT3β mutant cell line. Transcriptional activation was also increased in the STAT3α mutant cells compared with STAT3α WT cells as detected by a luciferase reporter assay. Moreover, STAT3αM206K mutant cells were resistant to JAK2 pathway inhibition compared to STAT3α WT cells. These results indicate that missense mutations in STAT3 increase signaling through the JAK/STAT pathway. JAK2 inhibitors may be useful in the patient with this STAT3 mutation as well as those with pathway activation by other mechanisms.
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Moon HS, Dalamaga M, Kim SY, Polyzos SA, Hamnvik OP, Magkos F, Paruthi J, Mantzoros CS. Leptin's role in lipodystrophic and nonlipodystrophic insulin-resistant and diabetic individuals. Endocr Rev 2013; 34:377-412. [PMID: 23475416 PMCID: PMC3660716 DOI: 10.1210/er.2012-1053] [Citation(s) in RCA: 187] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Leptin is an adipocyte-secreted hormone that has been proposed to regulate energy homeostasis as well as metabolic, reproductive, neuroendocrine, and immune functions. In the context of open-label uncontrolled studies, leptin administration has demonstrated insulin-sensitizing effects in patients with congenital lipodystrophy associated with relative leptin deficiency. Leptin administration has also been shown to decrease central fat mass and improve insulin sensitivity and fasting insulin and glucose levels in HIV-infected patients with highly active antiretroviral therapy (HAART)-induced lipodystrophy, insulin resistance, and leptin deficiency. On the contrary, the effects of leptin treatment in leptin-replete or hyperleptinemic obese individuals with glucose intolerance and diabetes mellitus have been minimal or null, presumably due to leptin tolerance or resistance that impairs leptin action. Similarly, experimental evidence suggests a null or a possibly adverse role of leptin treatment in nonlipodystrophic patients with nonalcoholic fatty liver disease. In this review, we present a description of leptin biology and signaling; we summarize leptin's contribution to glucose metabolism in animals and humans in vitro, ex vivo, and in vivo; and we provide insights into the emerging clinical applications and therapeutic uses of leptin in humans with lipodystrophy and/or diabetes.
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Affiliation(s)
- Hyun-Seuk Moon
- Division of Endocrinology, Diabetes, and Metabolism, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts 02215, USA
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Posttranslational protein knockdown coupled to receptor tyrosine kinase activation with phosphoPROTACs. Proc Natl Acad Sci U S A 2013; 110:8942-7. [PMID: 23674677 DOI: 10.1073/pnas.1217206110] [Citation(s) in RCA: 115] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Posttranslational knockdown of a specific protein is an attractive approach for examining its function within a system. Here we introduce phospho-dependent proteolysis targeting chimeras (phosphoPROTACs), a method to couple the conditional degradation of targeted proteins to the activation state of particular kinase-signaling pathways. We generated two phosphoPROTACs that couple the tyrosine phosphorylation sequences of either the nerve growth factor receptor, TrkA (tropomyosin receptor kinase A), or the neuregulin receptor, ErbB3 (erythroblastosis oncogene B3), with a peptide ligand for the E3 ubiquitin ligase von Hippel Lindau protein. These phosphoPROTACs recruit either the neurotrophic signaling effector fibroblast growth factor receptor substrate 2α or the survival-promoting phosphatidylinositol-3-kinase, respectively, to be ubiquitinated and degraded upon activation of specific receptor tyrosine kinases and phosphorylation of the phosphoPROTACs. We demonstrate the ability of these phosphoPROTACs to suppress the short- and long-term effects of their respective activating receptor tyrosine kinase pathways both in vitro and in vivo. In addition, we show that activation of phosphoPROTACs is entirely dependent on their kinase-mediated phosphorylation, as phenylalanine-containing null variants are inactive. Furthermore, stimulation of unrelated growth factor receptors does not induce target protein knockdown. Although comparable in efficiency to RNAi, this approach has the added advantage of providing a degree of temporal and dosing control as well as cell-type selectivity unavailable using nucleic acid-based strategies. By varying the autophosphorylation sequence of a phosphoPROTAC, it is conceivable that other receptor tyrosine kinase/effector pairings could be similarly exploited to achieve other biological effects.
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36
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Inhibitory Mechanism of Signal Transduction through Chicken Leptin Receptor by Suppressor of Cytokine Signaling 3 (SOCS3). J Poult Sci 2013. [DOI: 10.2141/jpsa.0120166] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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Enhancement of leptin receptor signaling by SOCS3 deficiency induces development of gastric tumors in mice. Oncogene 2012. [DOI: 10.1038/onc.2012.540] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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Random mutagenesis MAPPIT analysis identifies binding sites for Vif and Gag in both cytidine deaminase domains of Apobec3G. PLoS One 2012; 7:e44143. [PMID: 22970171 PMCID: PMC3438196 DOI: 10.1371/journal.pone.0044143] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2012] [Accepted: 08/01/2012] [Indexed: 11/19/2022] Open
Abstract
The mammalian two-hybrid system MAPPIT allows the detection of protein-protein interactions in intact human cells. We developed a random mutagenesis screening strategy based on MAPPIT to detect mutations that disrupt the interaction of one protein with multiple protein interactors simultaneously. The strategy was used to detect residues of the human cytidine deaminase Apobec3G that are important for its homodimerization and its interaction with the HIV-1 Gag and Vif proteins. The strategy is able to identify the previously described head-to-head homodimerization interface in the N-terminal domain of Apobec3G. Our analysis further detects two new potential interaction surfaces in the N-and C-terminal domain of Apobec3G for interaction with Vif and Gag or for Apobec3G dimerization.
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Su H, Jiang L, Carter-Su C, Rui L. Glucose enhances leptin signaling through modulation of AMPK activity. PLoS One 2012; 7:e31636. [PMID: 22359610 PMCID: PMC3281098 DOI: 10.1371/journal.pone.0031636] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2011] [Accepted: 01/10/2012] [Indexed: 01/08/2023] Open
Abstract
Leptin exerts its action by binding to and activating the long form of leptin receptors (LEPRb). LEPRb activates JAK2 that subsequently phosphorylates and activates STAT3. The JAK2/STAT3 pathway is required for leptin control of energy balance and body weight. Defects in leptin signaling lead to leptin resistance, a primary risk factor for obesity. Body weight is also regulated by nutrients, including glucose. Defects in glucose sensing also contribute to obesity. Here we report crosstalk between leptin and glucose. Glucose starvation blocked the ability of leptin to stimulate tyrosyl phosphorylation and activation of JAK2 and STAT3 in a variety of cell types. Glucose dose-dependently enhanced leptin signaling. In contrast, glucose did not enhance growth hormone-stimulated phosphorylation of JAK2 and STAT5. Glucose starvation or 2-deoxyglucose-induced inhibition of glycolysis activated AMPK and inhibited leptin signaling; pharmacological inhibition of AMPK restored the ability of leptin to stimulate STAT3 phosphorylation. Conversely, pharmacological activation of AMPK was sufficient to inhibit leptin signaling and to block the ability of glucose to enhance leptin signaling. These results suggest that glucose and/or its metabolites play a permissive role in leptin signaling, and that glucose enhances leptin sensitivity at least in part by attenuating the ability of AMPK to inhibit leptin signaling.
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Affiliation(s)
| | | | | | - Liangyou Rui
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, Michigan, United States of America
- * E-mail:
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40
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Abstract
The hormone leptin, secreted predominantly from adipose tissue, plays a crucial role in the regulation of numerous neuroendocrine functions, from energy homeostasis to reproduction. Genetic deficiency as a consequence of leptin or leptin receptor mutations, although rare in humans, leads to early onset of chronic hyperphagia and massive obesity. In most human obesity, however, leptin levels are chronically elevated. Under these conditions of persistent hyperleptinaemia, and particularly when obesity is associated with a high-fat diet, leptin resistance develops, and signalling through the leptin receptor is curtailed, fuelling further weight gain. Here, we review the role of leptin receptors in the regulation of feeding and obesity development. Leptin receptors are found in each of the major components of the CNS "feeding" circuitry-the brainstem, hypothalamus and distributed reward centres. Through these receptors, leptin exerts influences on signalling and integration within these circuits to alter feeding behaviours. Although some progress is now being made with peptide analogues, the leptin receptor has not proved to be amenable to small molecule pharmacological intervention to date. Where clinical benefit from recombinant leptin administration has been achieved, this has been under circumstances of complete endogenous leptin deficiency or relative hypoleptinaemia such as in lipodystrophy.
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Affiliation(s)
- Elizabeth C Cottrell
- Centre for Cardiovascular Science, Queen's Medical Research Institute, University of Edinburgh, Scotland, EH16 4TH, UK
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Metlakunta AS, Sahu M, Yasukawa H, Dhillon SS, Belsham DD, Yoshimura A, Sahu A. Neuronal suppressor of cytokine signaling-3 deficiency enhances hypothalamic leptin-dependent phosphatidylinositol 3-kinase signaling. Am J Physiol Regul Integr Comp Physiol 2011; 300:R1185-93. [PMID: 21325649 DOI: 10.1152/ajpregu.00794.2010] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Suppressor of cytokine signaling-3 (SOCS3) is thought to be involved in the development of central leptin resistance and obesity by inhibiting STAT3 pathway. Because phosphatidylinositol 3-kinase (PI3K) pathway plays an important role in transducing leptin action in the hypothalamus, we examined whether SOCS3 exerted an inhibition on this pathway. We first determined whether leptin sensitivity in the hypothalamic PI3K pathway was increased in brain-specific Socs3-deficient (NesKO) mice. In NesKO mice, hypothalamic insulin receptor substrate-1 (IRS1)-associated PI3K activity was significantly increased at 30 min and remained elevated up to 2 h after leptin intraperitoneal injection, but in wild-type (WT) littermates, the significant increase was only at 30 min. Hypothalamic p-STAT3 levels were increased up to 5 h in NesKO as opposed to 2 h in WT mice. In food-restricted WT mice with reduced body weight, leptin increased hypothalamic PI3K activity only at 30 min, and p-STAT3 levels at 30-120 min postinjection. These results suggest increased leptin sensitivity in both PI3K and STAT3 pathways in the hypothalamus of NesKO mice, which was not due to a lean phenotype. In the next experiment with a clonal hypothalamic neuronal cell line expressing proopiomelanocortin, we observed that whereas leptin significantly increased IRS1-associated PI3K activity and p-JAK2 levels in cells transfected with control vector, it failed to do so in SOCS3-overexpressed cells. Altogether, these results imply a SOCS3 inhibition of the PI3K pathway of leptin signaling in the hypothalamus, which may be one of the mechanisms behind the development of central leptin resistance and obesity.
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Affiliation(s)
- Anantha S Metlakunta
- Dept. of Obstetrics, Gynecology and Reproductive Sciences, University of Pittsburgh School of Medicine, Magee-Womens Research Institute, 204 Craft Avenue, Pittsburgh, PA 15213, USA
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Williams KW, Scott MM, Elmquist JK. Modulation of the central melanocortin system by leptin, insulin, and serotonin: co-ordinated actions in a dispersed neuronal network. Eur J Pharmacol 2011; 660:2-12. [PMID: 21211525 DOI: 10.1016/j.ejphar.2010.11.042] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2010] [Revised: 10/08/2010] [Accepted: 11/02/2010] [Indexed: 10/18/2022]
Abstract
Over the past century, prevalent models of energy and glucose homeostasis have been developed from a better understanding of the neural circuits underlying obesity and diabetes. From the early hypothalamic lesion reports to the more recent pharmacological and molecular/genetic studies, the hypothalamic melanocortin system has been shown to play a critical role in the regulation of metabolism. This review attempts to highlight contributions to our current understanding of how numerous neuromodulators (leptin, insulin, and serotonin) integrate with the central melanocortin system to coordinate alterations in energy and glucose balance.
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Affiliation(s)
- Kevin W Williams
- Division of Hypothalamic Research, Department of Internal Medicine, The University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
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43
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Dobrin JS, Lebeche D. Diabetic cardiomyopathy: signaling defects and therapeutic approaches. Expert Rev Cardiovasc Ther 2010; 8:373-91. [PMID: 20222816 DOI: 10.1586/erc.10.17] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Diabetes mellitus is the world's fastest growing disease with high morbidity and mortality rates, predominantly as a result of heart failure. A significant number of diabetic patients exhibit diabetic cardiomyopathy; that is, left ventricular dysfunction independent of coronary artery disease or hypertension. The pathogenesis of diabetic cardiomyopathy is complex, and is characterized by dysregulated lipid metabolism, insulin resistance, mitochondrial dysfunction and disturbances in adipokine secretion and signaling. These abnormalities lead to impaired calcium homeostasis, ultimately resulting in lusitropic and inotropic defects. This article discusses the impact of these hallmark factors in diabetic cardiomyopathy, and concludes with a survey of available and emerging therapeutic modalities.
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Affiliation(s)
- Joseph S Dobrin
- Cardiovascular Research Center, Mount Sinai School of Medicine, New York, NY 10029, USA.
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44
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Knobelspies H, Zeidler J, Hekerman P, Bamberg-Lemper S, Becker W. Mechanism of attenuation of leptin signaling under chronic ligand stimulation. BMC BIOCHEMISTRY 2010; 11:2. [PMID: 20059770 PMCID: PMC2821298 DOI: 10.1186/1471-2091-11-2] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/07/2009] [Accepted: 01/08/2010] [Indexed: 01/04/2023]
Abstract
Background Leptin is an adipocyte-derived hormone that acts via its hypothalamic receptor (LEPRb) to regulate energy balance. A downstream effect essential for the weight-regulatory action of leptin is the phosphorylation and activation of the latent transcription factor STAT3 by LEPRb-associated Janus kinases (JAKs). Obesity is typically associated with chronically elevated leptin levels and a decreased ability of LEPRb to activate intracellular signal transduction pathways (leptin resistance). Here we have studied the roles of the intracellular tyrosine residues in the negative feedback regulation of LEPRb-signaling under chronic leptin stimulation. Results Mutational analysis showed that the presence of either Tyr985 and Tyr1077 in the intracellular domain of LEPRb was sufficient for the attenuation of STAT3 phosphorylation, whereas mutation of both tyrosines rendered LEPRb resistant to feedback regulation. Overexpression and RNA interference-mediated downregulation of suppressor of cytokine signaling 3 (SOCS3) revealed that both Tyr985 and Tyr1077 were capable of supporting the negative modulatory effect of SOCS3 in reporter gene assays. In contrast, the inhibitory effect of SOCS1 was enhanced by the presence of Tyr985 but not Tyr1077. Finally, the reduction of the STAT-phosphorylating activity of the LEPRb complex after 2 h of leptin stimulation was not accompanied by the dephosphorylation or degradation of LEPRb or the receptor-associated JAK molecule, but depended on Tyr985 and/or Tyr1077. Conclusions Both Tyr985 and Tyr1077 contribute to the negative regulation of LEPRb signaling. The inhibitory effects of SOCS1 and SOCS3 differ in the dependence on the tyrosine residues in the intracellular domain of LEPRb.
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Affiliation(s)
- Holger Knobelspies
- Institute of Pharmacology and Toxicology, Medical Faculty of the RWTH Aachen University, Wendlingweg 2, 52074 Aachen, Germany
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45
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Lavens D, Peelman F, Van der Heyden J, Uyttendaele I, Catteeuw D, Verhee A, Van Schoubroeck B, Kurth J, Hallenberger S, Clayton R, Tavernier J. Definition of the interacting interfaces of Apobec3G and HIV-1 Vif using MAPPIT mutagenesis analysis. Nucleic Acids Res 2009; 38:1902-12. [PMID: 20015971 PMCID: PMC2847223 DOI: 10.1093/nar/gkp1154] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
The host restriction factor Apobec3G is a cytidine deaminase that incorporates into HIV-1 virions and interferes with viral replication. The HIV-1 accessory protein Vif subverts Apobec3G by targeting it for proteasomal degradation. We propose a model in which Apobec3G N-terminal domains symmetrically interact via a head-to-head interface containing residues 122 RLYYFW 127. To validate this model and to characterize the Apobec3G–Apobec3G and the Apobec3G–Vif interactions, the mammalian protein–protein interaction trap two-hybrid technique was used. Mutations in the head-to-head interface abrogate the Apobec3G–Apobec3G interaction. All mutations that inhibit Apobec3G–Apobec3G binding also inhibit the Apobec3G–Vif interaction, indicating that the head-to head interface plays an important role in the interaction with Vif. Only the D128K, P129A and T32Q mutations specifically affect the Apobec3G–Vif association. In our model, D128, P129 and T32 cluster at the edge of the head-to-head interface, possibly forming a Vif binding site composed of two Apobec3G molecules. We propose that Vif either binds at the Apobec3G head-to-head interface or associates with an RNA-stabilized Apobec3G oligomer.
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Affiliation(s)
- Delphine Lavens
- Department of Medical Protein Research, VIB, Department of Biochemistry, Ghent University, A. Baertsoenkaai 3, 9000 Ghent
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Abstract
The brain controls energy homeostasis and body weight by integrating various metabolic signals. Leptin, an adipose-derived hormone, conveys critical information about peripheral energy storage and availability to the brain. Leptin decreases body weight by both suppressing appetite and promoting energy expenditure. Leptin directly targets hypothalamic neurons, including AgRP and POMC neurons. These leptin-responsive neurons widely connect to other neurons in the brain, forming a sophisticated neurocircuitry that controls energy intake and expenditure. The anorexigenic actions of leptin are mediated by LEPRb, the long form of the leptin receptor, in the hypothalamus. LEPRb activates both JAK2-dependent and -independent pathways, including the STAT3, PI 3-kinase, MAPK, AMPK, and mTOR pathways. These pathways act coordinately to form a network that fully mediates leptin response. LEPRb signaling is regulated by both positive (e.g., SH2B1) and negative (e.g., SOCS3 and PTP1B) regulators and by endoplasmic reticulum stress. Leptin resistance, a primary risk factor for obesity, likely results from impairment in leptin transport, LEPRb signaling, and/or the neurocircuitry of energy balance.
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Affiliation(s)
- David L Morris
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, Mchigan 48109-0622, USA
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47
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Lievens S, Vanderroost N, Van der Heyden J, Gesellchen V, Vidal M, Tavernier J. Array MAPPIT: high-throughput interactome analysis in mammalian cells. J Proteome Res 2009; 8:877-86. [PMID: 19159283 DOI: 10.1021/pr8005167] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Physical interactions between proteins play a key role in probably every cellular process. Efforts to chart the protein interaction networks are ongoing in a number of model organisms using a diversity of approaches. The resulting genome-wide interaction maps will provide a scaffold for further detailed functional analysis. We developed MAPPIT, a mammalian two-hybrid approach that allows identification and analysis of mammalian protein-protein interactions in their native environment. Here, we introduce an efficient MAPPIT assay that permits high-throughput screening of arrayed collections of proteins and complements a previously published cDNA library screening approach. We validated both methods in screens for interaction partners of the Cullin-based E3 ubiquitin ligase subunits SKP1 and Elongin C. In addition to a number of known interactors, novel SKP1 and Elongin C binding proteins were identified. The array assay is an important addition to the MAPPIT suite of technologies that is expected to significantly increase its utility as a toolbox to screen for novel interactors of proteins or small molecules.
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Affiliation(s)
- Sam Lievens
- Department of Medical Protein Research, VIB, A. Baertsoenkaai 3, 9000 Ghent, Belgium
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48
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Procaccini C, Lourenco EV, Matarese G, La Cava A. Leptin signaling: A key pathway in immune responses. ACTA ACUST UNITED AC 2009; 4:22-30. [PMID: 19774101 DOI: 10.2174/157436209787048711] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Leptin is a hormone whose central role is to regulate endocrine functions and to control energy expenditure. After the discovery that leptin can also have pro-inflammatory effects, several studies have tried to address - at the molecular level - the pathways involved in leptin-induced modulation of the immune functions in normal and pathologic conditions. The signaling events influenced by leptin after its binding to the leptin receptor have been under scrutiny in the past few years, and considerable experimental work has elucidated the consequences of leptin effects on immune cells. This review examines the biochemistry, function and regulation of leptin signaling in view of possible intervention on this molecule for a better management and therapy of immune-mediated diseases.
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Affiliation(s)
- Claudio Procaccini
- Department of Medicine, University of California Los Angeles, Los Angeles, California 90095
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Gove ME, Rhodes DH, Pini M, van Baal JW, Sennello JA, Fayad R, Cabay RJ, Myers MG, Fantuzzi G. Role of leptin receptor-induced STAT3 signaling in modulation of intestinal and hepatic inflammation in mice. J Leukoc Biol 2008; 85:491-6. [PMID: 19052144 DOI: 10.1189/jlb.0808508] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Leptin-deficient ob/ob mice are resistant to dextran sulfate sodium (DSS)-induced colitis and Concanavalin A (Con A)-induced hepatitis. However, the signal transduction pathways involved have not been identified. The present study investigated the effect of leptin-induced STAT3 signaling in the DSS and Con A models. Mice carrying a leptin receptor (LEPR) gene mutant for Y1138 (s/s mice), with abrogated leptin-induced STAT3 signaling, were compared with wild-type (WT) and LEPR-deficient db/db mice. Administration of DSS to s/s mice resulted in a clinical score and colon shortening of intermediate severity compared with disease induced in WT and db/db mice-the latter group having the lowest disease severity. A comparable degree of inflammatory infiltrate and epithelial damage was observed in the colon of WT and s/s mice, and these parameters were reduced in db/db mice. Levels of IFN-gamma, IL-6, IL-10, and TNF-alpha were comparable in the colon of s/s and db/db mice, and a similar trend was observed for CXCL2. s/s and WT mice developed severe liver disease in response to Con A, whereas db/db mice were protected. However, Con A-induced serum IL-6 and TNF-alpha levels in s/s mice mimicked levels observed in db/db rather than WT mice. In conclusion, lack of leptin-induced STAT3 signaling is associated with reduced cytokine production following DSS and Con A administration, but it appears to sensitize mice to the effects of proinflammatory mediators.
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Affiliation(s)
- Melissa E Gove
- Kinesiology and Nutrition Department, University of Illinois at Chicago, Chicago, IL 60612, USA
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50
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Zou T, Ouyang L, Chen L, Dong W, Qiao H, Liu Y, Qi Y. The role of microtubule-associated protein 1S in SOCS3 regulation of IL-6 signaling. FEBS Lett 2008; 582:4015-22. [PMID: 19027008 DOI: 10.1016/j.febslet.2008.10.055] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2008] [Revised: 10/09/2008] [Accepted: 10/22/2008] [Indexed: 10/21/2022]
Abstract
Cytokine-induced suppressor of cytokine signaling (SOCS) proteins function as feedback inhibitors of cytokine receptor signaling by inhibiting the Janus kinase-signal transducer and activator of transcription (JAK-STAT) signal transduction pathway. In this report, microtubule-associated protein 1S (MAP1), a member of the MAP1 family, was identified as a novel SOCS3 interacting protein. MAP1S could bind with microtubules and actin, and decorated and stabilized microtubules. A perinuclear co-localization was discovered between MAP1S and SOCS3. In MAP1S deficient macrophages, inhibition of SOCS3 on STAT3 phosphorylation can be partially hindered in the presence of interleukin-6 (IL-6) and lipopolysaccharide (LPS). The microtubule-depolymerizing drug nocodazole also disrupted the inhibitory activity of the SOCS3 protein. These results suggest that the interaction of SOCS3 with MAP1S and the integrity of the microtubule cytoskeleton play an important role in the negative regulation of SOCS3 on IL-6 signaling.
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Affiliation(s)
- Tingting Zou
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, Hubei 430072, PR China
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