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Martínez Báez A, Ayala G, Pedroza-Saavedra A, González-Sánchez HM, Chihu Amparan L. Phosphorylation Codes in IRS-1 and IRS-2 Are Associated with the Activation/Inhibition of Insulin Canonical Signaling Pathways. Curr Issues Mol Biol 2024; 46:634-649. [PMID: 38248343 PMCID: PMC10814773 DOI: 10.3390/cimb46010041] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2023] [Revised: 12/23/2023] [Accepted: 12/28/2023] [Indexed: 01/23/2024] Open
Abstract
Insulin receptor substrates 1 and 2 (IRS-1 and IRS-2) are signaling adaptor proteins that participate in canonical pathways, where insulin cascade activation occurs, as well as in non-canonical pathways, in which phosphorylation of substrates is carried out by a diverse array of receptors including integrins, cytokines, steroid hormones, and others. IRS proteins are subject to a spectrum of post-translational modifications essential for their activation, encompassing phosphorylation events in distinct tyrosine, serine, and threonine residues. Tyrosine residue phosphorylation is intricately linked to the activation of the insulin receptor cascade and its interaction with SH2 domains within a spectrum of proteins, including PI3K. Conversely, serine residue phosphorylation assumes a different function, serving to attenuate the effects of insulin. In this review, we have identified over 50 serine residues within IRS-1 that have been reported to undergo phosphorylation orchestrated by a spectrum of kinases, thereby engendering the activation or inhibition of different signaling pathways. Furthermore, we delineate the phosphorylation of over 10 distinct tyrosine residues at IRS-1 or IRS-2 in response to insulin, a process essential for signal transduction and the subsequent activation of PI3K.
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Affiliation(s)
- Anabel Martínez Báez
- Infection Disease Research Center, National Institute of Public Health, Cuernavaca 62100, Mexico; (A.M.B.); (G.A.); (A.P.-S.)
| | - Guadalupe Ayala
- Infection Disease Research Center, National Institute of Public Health, Cuernavaca 62100, Mexico; (A.M.B.); (G.A.); (A.P.-S.)
| | - Adolfo Pedroza-Saavedra
- Infection Disease Research Center, National Institute of Public Health, Cuernavaca 62100, Mexico; (A.M.B.); (G.A.); (A.P.-S.)
| | - Hilda M. González-Sánchez
- CONAHCYT—Infection Disease Research Center, National Institute of Public Health, Cuernavaca 62100, Mexico;
| | - Lilia Chihu Amparan
- Infection Disease Research Center, National Institute of Public Health, Cuernavaca 62100, Mexico; (A.M.B.); (G.A.); (A.P.-S.)
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2
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Hsu MF, Ito Y, Afkarian M, Haj FG. Deficiency of the Src homology phosphatase 2 in podocytes is associated with renoprotective effects in mice under hyperglycemia. Cell Mol Life Sci 2022; 79:516. [PMID: 36102977 PMCID: PMC10987040 DOI: 10.1007/s00018-022-04517-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2021] [Revised: 07/26/2022] [Accepted: 08/08/2022] [Indexed: 11/03/2022]
Abstract
Diabetic nephropathy (DN) is a significant complication of diabetes and the leading cause of end-stage renal disease. Hyperglycemia-induced dysfunction of the glomerular podocytes is a major contributor to the deterioration of renal function in DN. Previously, we demonstrated that podocyte-specific disruption of the Src homology phosphatase 2 (Shp2) ameliorated lipopolysaccharide-induced renal injury. This study aims to evaluate the contribution of Shp2 to podocyte function under hyperglycemia and explore the molecular underpinnings. We report elevated Shp2 in the E11 podocyte cell line under high glucose and the kidney under streptozotocin- and high-fat diet-induced hyperglycemia. Consistently, Shp2 disruption in podocytes was associated with partial renoprotective effects under hyperglycemia, as evidenced by the preserved renal function. At the molecular level, Shp2 deficiency was associated with altered renal insulin signaling and diminished hyperglycemia-induced renal endoplasmic reticulum stress, inflammation, and fibrosis. Additionally, Shp2 knockdown in E11 podocytes mimicked the in vivo deficiency of this phosphatase and ameliorated the deleterious impact of high glucose, whereas Shp2 reconstitution reversed these effects. Moreover, Shp2 deficiency attenuated high glucose-induced E11 podocyte migration. Further, we identified the protein tyrosine kinase FYN as a putative mediator of Shp2 signaling in podocytes under high glucose. Collectively, these findings suggest that Shp2 inactivation may afford protection to podocytes under hyperglycemia and highlight this phosphatase as a potential target to ameliorate glomerular dysfunction in DN.
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Affiliation(s)
- Ming-Fo Hsu
- Department of Nutrition, University of California Davis, Davis, CA, 95616, USA.
| | - Yoshihiro Ito
- Department of Nutrition, University of California Davis, Davis, CA, 95616, USA
- Department of Endocrinology and Diabetes, and Department of CKD Initiatives/Nephrology, Nagoya University Graduate School of Medicine, Nagoya, 466-8560, Japan
| | - Maryam Afkarian
- Division of Nephrology, Department of Internal Medicine, University of California Davis, Sacramento, CA, 95817, USA
| | - Fawaz G Haj
- Department of Nutrition, University of California Davis, Davis, CA, 95616, USA.
- Comprehensive Cancer Center, University of California Davis, Sacramento, CA, 95817, USA.
- Division of Endocrinology, Diabetes, and Metabolism, Department of Internal Medicine, University of California Davis, Sacramento, CA, 95817, USA.
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Oral administration of Grifola frondosa affect lipid metabolism and insulin signaling pathway on BKS. Cg-+Leprdb/+Leprdb/OlaHsd mouse. JOURNAL OF ANIMAL REPRODUCTION AND BIOTECHNOLOGY 2021. [DOI: 10.12750/jarb.36.4.203] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
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Brandt AM, Kania JM, Gonzalez ML, Johnson SE. Hepatocyte growth factor acts as a mitogen for equine satellite cells via protein kinase C δ-directed signaling. J Anim Sci 2018; 96:3645-3656. [PMID: 29917108 PMCID: PMC6127786 DOI: 10.1093/jas/sky234] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2018] [Accepted: 06/13/2018] [Indexed: 12/26/2022] Open
Abstract
Hepatocyte growth factor (HGF) signals mediate mouse skeletal muscle stem cell, or satellite cell (SC), reentry into the cell cycle and myoblast proliferation. Because the athletic horse experiences exercise-induced muscle damage, the objective of the experiment was to determine the effect of HGF on equine SC (eqSC) bioactivity. Fresh isolates of adult eqSC were incubated with increasing concentrations of HGF and the initial time to DNA synthesis was measured. Media supplementation with HGF did not shorten (P > 0.05) the duration of G0/G1 transition suggesting the growth factor does not affect activation. Treatment with 25 ng/mL HGF increased (P < 0.05) eqSC proliferation that was coincident with phosphorylation of extracellular signal-regulated kinase (ERK)1/2 and AKT serine/threonine kinase 1 (AKT1). Chemical inhibition of the upstream effectors of ERK1/2 or AKT1 elicited no effect (P > 0.05) on HGF-mediated 5-ethynyl-2'-deoxyuridine (EdU) incorporation. By contrast, treatment of eqSC with 2 µm Gö6983, a pan-protein kinase C (PKC) inhibitor, blocked (P < 0.05) HGF-initiated mitotic activity. Gene-expression analysis revealed that eqSC express PKCα, PKCδ, and PKCε isoforms. Knockdown of PKCδ with a small interfering RNA (siRNA) prevented (P > 0.05) HGF-mediated EdU incorporation. The siPKCδ was specific to the kinase and did not affect (P > 0.05) expression of either PKCα or PKCε. Treatment of confluent eqSC with 25 ng/mL HGF suppressed (P < 0.05) nuclear myogenin expression during the early stages of differentiation. These results demonstrate that HGF may not affect activation but can act as a mitogen and modest suppressor of differentiation.
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Affiliation(s)
- Amanda M Brandt
- Department of Animal and Poultry Sciences, Virginia Polytechnic Institute and State University, Blacksburg VA
| | - Joanna M Kania
- Department of Animal and Poultry Sciences, Virginia Polytechnic Institute and State University, Blacksburg VA
| | - Madison L Gonzalez
- Department of Animal and Poultry Sciences, Virginia Polytechnic Institute and State University, Blacksburg VA
| | - Sally E Johnson
- Department of Animal and Poultry Sciences, Virginia Polytechnic Institute and State University, Blacksburg VA
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Protective effects of the GLP-1 mimetic exendin-4 in Parkinson's disease. Neuropharmacology 2017; 136:260-270. [PMID: 28927992 DOI: 10.1016/j.neuropharm.2017.09.023] [Citation(s) in RCA: 56] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2017] [Revised: 09/12/2017] [Accepted: 09/15/2017] [Indexed: 02/07/2023]
Abstract
There is increasing interest in the potential role of glucagon-like peptide-1 (GLP-1) receptor agonists as neuroprotective treatments in neurodegenerative diseases including Parkinson's disease following the publication of the results of the Exenatide-PD trial. Of the current GLP-1 receptor agonists already licensed to treat Type 2 diabetes several including exenatide, liraglutide and lixisenatide are the subject of ongoing clinical trials in PD. The underlying rationale for using drugs licensed and effective for T2DM in PD patients therefore needs to be scrutinized, and the results obtained to date critically reviewed. We review the relationship between insulin resistance and Parkinson's disease, the implications on pathogenesis and the efforts to reposition GLP-1 agonists as potential treatments for Parkinson's disease and give an overview of the pre-clinical and clinical data supporting the use of exenatide in Parkinson's disease with a discussion regarding possible mechanisms of action. This article is part of the Special Issue entitled 'Metabolic Impairment as Risk Factors for Neurodegenerative Disorders.'
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6
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FAK phosphorylation plays a central role in thrombin-induced RPE cell migration. Cell Signal 2017; 36:56-66. [DOI: 10.1016/j.cellsig.2017.04.016] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2017] [Revised: 04/21/2017] [Accepted: 04/22/2017] [Indexed: 02/06/2023]
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Röhling M, Herder C, Stemper T, Müssig K. Influence of Acute and Chronic Exercise on Glucose Uptake. J Diabetes Res 2016; 2016:2868652. [PMID: 27069930 PMCID: PMC4812462 DOI: 10.1155/2016/2868652] [Citation(s) in RCA: 59] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/23/2015] [Revised: 01/31/2016] [Accepted: 02/03/2016] [Indexed: 02/06/2023] Open
Abstract
Insulin resistance plays a key role in the development of type 2 diabetes. It arises from a combination of genetic predisposition and environmental and lifestyle factors including lack of physical exercise and poor nutrition habits. The increased risk of type 2 diabetes is molecularly based on defects in insulin signaling, insulin secretion, and inflammation. The present review aims to give an overview on the molecular mechanisms underlying the uptake of glucose and related signaling pathways after acute and chronic exercise. Physical exercise, as crucial part in the prevention and treatment of diabetes, has marked acute and chronic effects on glucose disposal and related inflammatory signaling pathways. Exercise can stimulate molecular signaling pathways leading to glucose transport into the cell. Furthermore, physical exercise has the potential to modulate inflammatory processes by affecting specific inflammatory signaling pathways which can interfere with signaling pathways of the glucose uptake. The intensity of physical training appears to be the primary determinant of the degree of metabolic improvement modulating the molecular signaling pathways in a dose-response pattern, whereas training modality seems to have a secondary role.
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Affiliation(s)
- Martin Röhling
- Institute for Clinical Diabetology, German Diabetes Center, Leibniz Center for Diabetes Research, Heinrich Heine University Düsseldorf, 40225 Düsseldorf, Germany
- German Center for Diabetes Research (DZD), Munich, 85764 Neuherberg, Germany
| | - Christian Herder
- Institute for Clinical Diabetology, German Diabetes Center, Leibniz Center for Diabetes Research, Heinrich Heine University Düsseldorf, 40225 Düsseldorf, Germany
- German Center for Diabetes Research (DZD), Munich, 85764 Neuherberg, Germany
| | - Theodor Stemper
- Department Fitness and Health, University Wuppertal, 42119 Wuppertal, Germany
| | - Karsten Müssig
- Institute for Clinical Diabetology, German Diabetes Center, Leibniz Center for Diabetes Research, Heinrich Heine University Düsseldorf, 40225 Düsseldorf, Germany
- German Center for Diabetes Research (DZD), Munich, 85764 Neuherberg, Germany
- Department of Endocrinology and Diabetology, Medical Faculty, Heinrich Heine University Düsseldorf, 40225 Düsseldorf, Germany
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8
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SHP2 sails from physiology to pathology. Eur J Med Genet 2015; 58:509-25. [PMID: 26341048 DOI: 10.1016/j.ejmg.2015.08.005] [Citation(s) in RCA: 158] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2015] [Revised: 07/24/2015] [Accepted: 08/30/2015] [Indexed: 02/08/2023]
Abstract
Over the two past decades, mutations of the PTPN11 gene, encoding the ubiquitous protein tyrosine phosphatase SHP2 (SH2 domain-containing tyrosine phosphatase 2), have been identified as the causal factor of several developmental diseases (Noonan syndrome (NS), Noonan syndrome with multiple lentigines (NS-ML), and metachondromatosis), and malignancies (juvenile myelomonocytic leukemia). SHP2 plays essential physiological functions in organism development and homeostasis maintenance by regulating fundamental intracellular signaling pathways in response to a wide range of growth factors and hormones, notably the pleiotropic Ras/Mitogen-Activated Protein Kinase (MAPK) and the Phosphoinositide-3 Kinase (PI3K)/AKT cascades. Analysis of the biochemical impacts of PTPN11 mutations first identified both loss-of-function and gain-of-function mutations, as well as more subtle defects, highlighting the major pathophysiological consequences of SHP2 dysregulation. Then, functional genetic studies provided insights into the molecular dysregulations that link SHP2 mutants to the development of specific traits of the diseases, paving the way for the design of specific therapies for affected patients. In this review, we first provide an overview of SHP2's structure and regulation, then describe its molecular roles, notably its functions in modulating the Ras/MAPK and PI3K/AKT signaling pathways, and its physiological roles in organism development and homeostasis. In the second part, we describe the different PTPN11 mutation-associated pathologies and their clinical manifestations, with particular focus on the biochemical and signaling outcomes of NS and NS-ML-associated mutations, and on the recent advances regarding the pathophysiology of these diseases.
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Xu E, Schwab M, Marette A. Role of protein tyrosine phosphatases in the modulation of insulin signaling and their implication in the pathogenesis of obesity-linked insulin resistance. Rev Endocr Metab Disord 2014; 15:79-97. [PMID: 24264858 DOI: 10.1007/s11154-013-9282-4] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Insulin resistance is a major disorder that links obesity to type 2 diabetes mellitus (T2D). It involves defects in the insulin actions owing to a reduced ability of insulin to trigger key signaling pathways in major metabolic tissues. The pathogenesis of insulin resistance involves several inhibitory molecules that interfere with the tyrosine phosphorylation of the insulin receptor and its downstream effectors. Among those, growing interest has been developed toward the protein tyrosine phosphatases (PTPs), a large family of enzymes that can inactivate crucial signaling effectors in the insulin signaling cascade by dephosphorylating their tyrosine residues. Herein we briefly review the role of several PTPs that have been shown to be implicated in the regulation of insulin action, and then focus on the Src homology 2 (SH2) domain-containing SHP1 and SHP2 enzymes, since recent reports have indicated major roles for these PTPs in the control of insulin action and glucose metabolism. Finally, the therapeutic potential of targeting PTPs for combating insulin resistance and alleviating T2D will be discussed.
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Affiliation(s)
- Elaine Xu
- Department of Medicine, Cardiology Axis of the Institut Universitaire de Cardiologie et de Pneumologie de Québec (Hôpital Laval), Ste-Foy, Québec, Canada, G1V 4G2
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10
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Abstract
The blood-testis barrier (BTB) is a large junctional complex composed of tight junctions, adherens junctions, and gap junctions between adjacent Sertoli cells in the seminiferous tubules of the testis. Maintenance of the BTB as well as the controlled disruption and reformation of the barrier is essential for spermatogenesis and male fertility. Tyrosine phosphorylation of BTB proteins is known to regulate the integrity of adherens and tight junctions found at the BTB. SHP2 is a nonreceptor protein tyrosine phosphatase (PTP) and a key regulator of growth factor-mediated tyrosine kinase signaling pathways. We found that SHP2 is localized to Sertoli-Sertoli cell junctions in rat testis. The overexpression of a constitutive active SHP2 mutant, SHP2 Q79R, up-regulated the BTB disruptor ERK1/2 via Src kinase in primary rat Sertoli cells in culture. Furthermore, focal adhesion kinase (FAK), which also supports BTB integrity, was found to interact with SHP2 and constitutive activation of SHP2 decreased FAK tyrosine phosphorylation. Expression of the SHP2 Q79R mutant in primary cultured Sertoli cells also resulted in the loss of tight junction and adherens junction integrity that corresponded with the disruption of the actin cytoskeleton and mislocalization of adherens junction and tight junction proteins N-cadherin, β-catenin, and ZO-1 away from the plasma membrane. These results suggest that SHP2 is a key regulator of BTB integrity and Sertoli cell support of spermatogenesis and fertility.
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Affiliation(s)
- Pawan Puri
- Center for Research in Reproductive Physiology, Department of Cell Biology and Molecular Physiology, Magee-Womens Research Institute, University of Pittsburgh, Pittsburgh, PA 15261, USA
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The Monascus metabolite monascin against TNF-α-induced insulin resistance via suppressing PPAR-γ phosphorylation in C2C12 myotubes. Food Chem Toxicol 2011; 49:2609-17. [DOI: 10.1016/j.fct.2011.07.005] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2011] [Revised: 07/02/2011] [Accepted: 07/06/2011] [Indexed: 01/11/2023]
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12
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Lee BH, Hsu WH, Pan TM. Inhibitory effects of dioscorea polysaccharide on TNF-α-induced insulin resistance in mouse FL83B cells. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2011; 59:5279-5285. [PMID: 21476604 DOI: 10.1021/jf200651c] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Dioscorea is a traditional medicinal food in Asia. This study investigated the anti-insulin resistance of dioscorea polysaccharide (DPS) in inflammatory factor (tumor necrosis factor-α; TNF-α) induced mouse normal liver FL83B cells. Insulin resistance was induced by treating cells with TNF-α (20 ng/mL) for 5 h; subsequently, the medium was replaced with insulin and DPS for 60 min of incubation (model 1; alleviating group). In addition, cells were cotreated with TNF-α and DPS for 5 h in model 2 (preventing group). DPS effectively increased glucose uptake and glucose transporter 2 (GLUT2) expression of insulin-resistant cells. Furthermore, DPS stimulated insulin receptor substrate (IRS) tyrosyl phosphorylation and increased p-Akt level to alleviate insulin resistance in models 1 and 2. Finally, the possible mechanism of DPS promoting insulin sensitivity in TNF-α-induced FL83B cells was investigated in this study. DPS may attenuate c-Jun N-terminal kinases (JNK) and insulin resistance caused by TNF-α induction; therefore, DPS also elevated the levels of p-IRS(Tyr) and p-Akt(Ser) to improve insulin sensitivity in the TNF-α-induced FL83B cells.
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Affiliation(s)
- Bao-Hong Lee
- Department of Biochemical Science and Technology, College of Life Science, National Taiwan University, Taipei, Taiwan
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13
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Hennige AM, Heni M, Machann J, Staiger H, Sartorius T, Hoene M, Lehmann R, Weigert C, Peter A, Bornemann A, Kroeber S, Pujol A, Franckhauser S, Bosch F, Schick F, Lammers R, Häring HU. Enforced expression of protein kinase C in skeletal muscle causes physical inactivity, fatty liver and insulin resistance in the brain. J Cell Mol Med 2010; 14:903-13. [PMID: 20569275 PMCID: PMC3823122 DOI: 10.1111/j.1582-4934.2008.00629.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Among the multitude of dysregulated signalling mechanisms that comprise insulin resistance in divergent organs, the primary events in the development of type 2 diabetes are not well established. As protein kinase C (PKC) activation is consistently present in skeletal muscle of obese and insulin resistant subjects, we generated a transgenic mouse model that overexpresses constitutively active PKC-β2 in skeletal muscle to test whether activation of PKC is sufficient to cause an aversive whole-body phenotype. Upon this genetic modification, increased serine phosphorylation in Irs1 was observed and followed by impaired 3H-deoxy-glucose uptake and muscle glycogen content, and transgenic mice exhibited insulin and glucose intolerance as they age. Muscle histochemistry revealed an increase in lipid deposition (intramyocellular lipids), and transgenic mice displayed impaired expression of transcriptional regulators of genes involved in fatty acid oxidation (peroxisome proliferator-activated receptor-γ, PGC-1β, acyl-CoA oxidase) and lipolysis (hormone-sensitive lipase). In this regard, muscle of transgenic mice exhibited a reduced capacity to oxidize palmitate and contained less mitochondria as determined by citrate synthase activity. Moreover, the phenotype included a profound decrease in the daily running distance, intra-abdominal and hepatic fat accumulation and impaired insulin action in the brain. Together, our data suggest that activation of a classical PKC in skeletal muscle as present in the pre-diabetic state is sufficient to cause disturbances in whole-body glucose and lipid metabolism followed by profound alterations in oxidative capacity, ectopic fat deposition and physical activity.
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Affiliation(s)
- Anita M Hennige
- University of Tuebingen, Department of Internal Medicine, Tübingen, Germany
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Matsuo K, Delibegovic M, Matsuo I, Nagata N, Liu S, Bettaieb A, Xi Y, Araki K, Yang W, Kahn BB, Neel BG, Haj FG. Altered glucose homeostasis in mice with liver-specific deletion of Src homology phosphatase 2. J Biol Chem 2010; 285:39750-8. [PMID: 20841350 DOI: 10.1074/jbc.m110.153734] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The Src homology 2 domain-containing protein-tyrosine phosphatase Shp2 has been implicated in a variety of growth factor signaling pathways, but its role in insulin signaling has remained unresolved. In vitro studies suggest that Shp2 is both a negative and positive regulator of insulin signaling, although its physiological function in a number of peripheral insulin-responsive tissues remains unknown. To address the metabolic role of Shp2 in the liver, we generated mice with either chronic or acute hepatic Shp2 deletion using tissue-specific Cre-LoxP and adenoviral Cre approaches, respectively. We then analyzed insulin sensitivity, glucose tolerance, and insulin signaling in liver-specific Shp2-deficient and control mice. Mice with chronic Shp2 deletion exhibited improved insulin sensitivity and increased glucose tolerance compared with controls. Acute Shp2 deletion yielded comparable results, indicating that the observed metabolic effects are directly caused by the lack of Shp2 in the liver. These findings correlated with, and were most likely caused by, direct dephosphorylation of insulin receptor substrate (IRS)1/2 in the liver, accompanied by increased PI3K/Akt signaling. In contrast, insulin-induced ERK activation was dramatically attenuated, yet there was no effect on the putative ERK site on IRS1 (Ser(612)) or on S6 kinase 1 activity. These studies show that Shp2 is a negative regulator of hepatic insulin action, and its deletion enhances the activation of PI3K/Akt pathway downstream of the insulin receptor.
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Affiliation(s)
- Kosuke Matsuo
- Department of Nutrition, University of California, Davis, California 95616, USA
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15
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Li L, He Q, Huang X, Man Y, Zhou Y, Wang S, Wang J, Li J. NOX3-derived reactive oxygen species promote TNF-alpha-induced reductions in hepatocyte glycogen levels via a JNK pathway. FEBS Lett 2010; 584:995-1000. [PMID: 20102709 DOI: 10.1016/j.febslet.2010.01.044] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2010] [Revised: 01/20/2010] [Accepted: 01/20/2010] [Indexed: 12/24/2022]
Abstract
TNF-alpha-induced insulin resistance is associated with generation of reactive oxygen species (ROS). This study aims at defining the link between ROS production and hepatic insulin resistance. Treatment with TNF-alpha increased ROS generation through activating NADPH oxidase 3 (NOX3) in HepG2 hepatocytes. Down-regulation of NOX3 using siRNA prevented TNF-alpha-induced decrease of cellular glycogen. In the cells treated with TNF-alpha, there were NOX3-dependent activation of JNK, inhibition of IRS1 and phosphorylation of AKT/PKB and GSK. In conclusion, the effects of TNF-alpha on hepatic insulin resistance appear to be, at least in part, mediated by NOX3-derived ROS through a JNK pathway.
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Affiliation(s)
- Lanfang Li
- Graduate School of Peking Union Medical College and Chinese Academy of Medical Sciences, The Key Laboratory of Geriatrics, Beijing Hospital & Beijing Institute of Geriatrics, Ministry of Health, Beijing 100730, China
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16
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Mayer CM, Belsham DD. Central insulin signaling is attenuated by long-term insulin exposure via insulin receptor substrate-1 serine phosphorylation, proteasomal degradation, and lysosomal insulin receptor degradation. Endocrinology 2010; 151:75-84. [PMID: 19887566 DOI: 10.1210/en.2009-0838] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Central insulin signaling is critical for the prevention of insulin resistance. Hyperinsulinemia contributes to insulin resistance, but it is not yet clear whether neurons are subject to cellular insulin resistance. We used an immortalized, hypothalamic, clonal cell line, mHypoE-46, which exemplifies neuronal function and expresses the components of the insulin signaling pathway, to determine how hyperinsulinemia modifies neuronal function. Western blot analysis indicated that prolonged insulin treatment of mHypoE-46 cells attenuated insulin signaling through phospho-Akt. To understand the mechanisms involved, time-course analysis was performed. Insulin exposure for 4 and 8 h phosphorylated Akt and p70-S6 kinase (S6K1), whereas 8 and 24 h treatment decreased insulin receptor (IR) and IR substrate 1 (IRS-1) protein levels. Insulin phosphorylation of S6K1 correlated with IRS-1 ser1101 phosphorylation and the mTOR-S6K1 pathway inhibitor rapamycin prevented IRS-1 serine phosphorylation. The proteasomal inhibitor epoxomicin and the lysosomal pathway inhibitor 3-methyladenine prevented the degradation of IRS-1 and IR by insulin, respectively, and pretreatment with rapamycin, epoxomicin, or 3-methyladenine prevented attenuation of insulin signaling by long-term insulin exposure. Thus, a sustained elevation of insulin levels diminishes neuronal insulin signaling through mTOR-S6K1-mediated IRS-1 serine phosphorylation, proteasomal degradation of IRS-1 and lysosomal degradation of the IR.
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Ragheb R, Shanab GML, Medhat AM, Seoudi DM, Adeli K, Fantus IG. Free fatty acid-induced muscle insulin resistance and glucose uptake dysfunction: evidence for PKC activation and oxidative stress-activated signaling pathways. Biochem Biophys Res Commun 2009; 389:211-6. [PMID: 19706288 DOI: 10.1016/j.bbrc.2009.08.106] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2009] [Accepted: 08/19/2009] [Indexed: 12/18/2022]
Abstract
In the present study, we examined the effects of free fatty acids (FFAs) on insulin sensitivity and signaling cascades in the C2C12 skeletal muscle cell culture system. Our data clearly manifested that the inhibitory effects of PKC on insulin signaling may at least in part be explained by the serine/threonine phosphorylation of IRS-1. Both oleate and palmitate treatment were able to increase the Serine(307) phosphorylation of IRS-1. IRS-1 Serine(307) phosphorylation is inducible which causes the inhibition of IRS-1 tyrosine phosphorylation by either IkappaB-kinase (IKK) or c-jun N-terminal kinase (JNK) as seen in our proteomic kinases screen. Furthermore, our proteomic data have also manifested that the two FFAs activate the IKKalpha/beta, the stress kinases S6 kinase p70 (p70SK), stress-activated protein kinase (SAPK), JNK, as well as p38 MAP kinase (p38MAPK). On the other hand, the antioxidant, Taurine at 10mM concentrations was capable of reversing the oleate-induced insulin resistance in myocytes as manifested from the glucose uptake data. Our current data point out the importance of FFA-induced insulin resistance via multiple signaling mechanisms.
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Affiliation(s)
- Rafik Ragheb
- University of Ain Shams, Department of Biochemistry, Faculty of Science, Cairo 11566, Egypt.
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Sacco A, Morcavallo A, Pandini G, Vigneri R, Belfiore A. Differential signaling activation by insulin and insulin-like growth factors I and II upon binding to insulin receptor isoform A. Endocrinology 2009; 150:3594-602. [PMID: 19443570 DOI: 10.1210/en.2009-0377] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
A variety of human malignancies overexpresses isoform A of the insulin receptor (IR-A) and produces IGFs (IGF-I and/or IGF-II). IR-A binds IGF-II with high affinity (although 4-fold lower than that for insulin), whereas it binds IGF-I with low affinity (approximately 30-fold lower than that for insulin). However, in engineered cells expressing only the IR-A, but not IGF-I receptor (R(-)/IR-A cells), IGF-II is a more potent mitogen than insulin. Herein, we investigated downstream signaling of IGF-II, IGF-I, and insulin in R(-)/IR-A cells to better understand their role in cell growth. We found that despite inducing a lower IR-A autophosphorylation than insulin, IGF-II was more potent than insulin for activating p70S6 kinase (p70S6K) and approximately equally potent in activating the early peaks of ERK1/2 and Akt. However, ERK1/2 activation persisted longer after IGF-II, whereas Akt activation persisted longer after insulin. Therefore, cells stimulated with IGF-II had a higher p70S6K/Akt activation ratio than cells stimulated with insulin. Remarkably, IGF-I also elicited a similar signaling pattern as IGF-II, despite inducing minimal IR-A autophosphorylation. ERK1/2 and protein kinase C seem to be involved in the preferential stimulation of p70S6K by IGFs. In conclusion, our study has identified a novel complex role of IR-A, which not only elicits a unique signaling pattern after IGF-II binding but also induces substantial downstream signaling upon binding to the low-affinity ligand IGF-I. These results underline the role of IR-A in physiology and disease.
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Affiliation(s)
- Antonella Sacco
- Endocrinology Unit, Department of Clinical and Experimental Medicine, University of Catanzaro, 88100 Catanzaro, Italy
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Lin CL, Lin JK. Epigallocatechin gallate (EGCG) attenuates high glucose-induced insulin signaling blockade in human hepG2 hepatoma cells. Mol Nutr Food Res 2008; 52:930-9. [DOI: 10.1002/mnfr.200700437] [Citation(s) in RCA: 112] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Morino K, Petersen KF, Shulman GI. Molecular mechanisms of insulin resistance in humans and their potential links with mitochondrial dysfunction. Diabetes 2006; 55 Suppl 2:S9-S15. [PMID: 17130651 PMCID: PMC2995546 DOI: 10.2337/db06-s002] [Citation(s) in RCA: 588] [Impact Index Per Article: 32.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Recent studies using magnetic resonance spectroscopy have shown that decreased insulin-stimulated muscle glycogen synthesis due to a defect in insulin-stimulated glucose transport activity is a major factor in the pathogenesis of type 2 diabetes. The molecular mechanism underlying defective insulin-stimulated glucose transport activity can be attributed to increases in intramyocellular lipid metabolites such as fatty acyl CoAs and diacylglycerol, which in turn activate a serine/threonine kinase cascade, thus leading to defects in insulin signaling through Ser/Thr phosphorylation of insulin receptor substrate (IRS)-1. A similar mechanism is also observed in hepatic insulin resistance associated with nonalcoholic fatty liver, which is a common feature of type 2 diabetes, where increases in hepatocellular diacylglycerol content activate protein kinase C-epsilon, leading to reduced insulin-stimulated tyrosine phosphorylation of IRS-2. More recently, magnetic resonance spectroscopy studies in healthy lean elderly subjects and healthy lean insulin-resistant offspring of parents with type 2 diabetes have demonstrated that reduced mitochondrial function may predispose these individuals to intramyocellular lipid accumulation and insulin resistance. Further analysis has found that the reduction in mitochondrial function in the insulin-resistant offspring can be mostly attributed to reductions in mitochondrial density. By elucidating the cellular and molecular mechanisms responsible for insulin resistance, these studies provide potential new targets for the treatment and prevention of type 2 diabetes.
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Affiliation(s)
- Katsutaro Morino
- Howard Hughes Medical Institute, Yale University School of Medicine, P.O. Box 9812, New Haven, CT 06536-8012, USA.
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21
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Bloch-Damti A, Potashnik R, Gual P, Le Marchand-Brustel Y, Tanti JF, Rudich A, Bashan N. Differential effects of IRS1 phosphorylated on Ser307 or Ser632 in the induction of insulin resistance by oxidative stress. Diabetologia 2006; 49:2463-73. [PMID: 16896943 DOI: 10.1007/s00125-006-0349-6] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/20/2006] [Accepted: 05/10/2006] [Indexed: 01/04/2023]
Abstract
AIMS/HYPOTHESIS Induction of stress kinases leading to serine hyperphosphorylation of IRS1 may link oxidative stress to insulin resistance. The aim of this study was to investigate the roles of the phosphorylated serine residues Ser307 and Ser632, two sites implicated in the inhibition of IRS1 function in insulin signalling. MATERIALS AND METHODS Fao hepatoma cells were exposed to an H(2)O(2)-generating system, and antibodies against the two phosphorylated serine residues were used for immunoprecipitation, immunoblot and immunofluorescence analyses. RESULTS Exposure to approximately 50 mumol/l H(2)O(2) for 2 h resulted in IRS1 phosphorylation on both Ser307 and Ser632, concomitant with activation of inhibitor kappa kinase beta (IKKbeta) and c-Jun kinase (JNK). Immunoprecipitation studies revealed that the maximum overlap between phospho (p) Ser307-IRS1 and pSer632-IRS1 was 20%, and confocal microscopy suggested distinct localisations of IRS1 molecules phosphorylated on either site. Although pSer307-IRS1 showed decreased insulin-induced tyrosine phosphorylation and interaction with phosphatidylinositol 3-kinase (PI3K) in response to insulin, pSer632-IRS1 molecules were normally tyrosine-phosphorylated and exhibited typical associated PI3K activity. Salicylic acid and SP600125 partially inhibited IKKbeta and JNK, respectively, which indicated distinct roles for these two kinases in the phosphorylation of IRS1 at the two serine sites. Protection against oxidation-mediated impairment in insulin-induced phosphorylation of protein kinase B/Akt and in glycogen synthesis was achieved only by combining salicylic acid and SP600125. CONCLUSIONS/INTERPRETATION These results suggest that pSer307-IRS1 and pSer632-IRS1 may define two minimally overlapping pools of IRS1 in response to oxidative stress, contributing differentially to insulin resistance. A combination of stress kinase inhibitors is required to protect against insulin resistance and IRS1 hyperphosphorylation induced by oxidative stress.
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Affiliation(s)
- A Bloch-Damti
- Department of Clinical Biochemistry, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, 84103, Israel
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Specific protein kinase C isoforms as transducers and modulators of insulin signaling. Mol Genet Metab 2006; 89:32-47. [PMID: 16798038 DOI: 10.1016/j.ymgme.2006.04.017] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/05/2006] [Revised: 04/23/2006] [Accepted: 04/23/2006] [Indexed: 12/14/2022]
Abstract
Recent studies implicate specific PKC isoforms in the insulin-signaling cascade. Insulin activates PKCs alpha, betaII, delta and zeta in several cell types. In addition, as will be documented in this review, certain members of the PKC family may also be activated and act upstream of PI3 and MAP kinases. Each of these isoforms has been shown one way or another either to mimic or to modify insulin-stimulated effects in one or all of the insulin-responsive tissues. Moreover, each of the isoforms has been shown to be activated by insulin stimulation or conditions important for effective insulin stimulation. Studies attempting to demonstrate a definitive role for any of the isoforms have been performed on different cells, ranging from appropriate model systems for skeletal muscle, liver and fat, such as primary cultures, and cell lines and even in vivo studies, including transgenic mice with selective deletion of specific PKC isoforms. In addition, studies have been done on certain expression systems such as CHO or HEK293 cells, which are far removed from the tissues themselves and serve mainly as vessels for potential protein-protein interactions. Thus, a clear picture for many of the isoforms remains elusive in spite of over two decades of intensive research. The recent intrusion of transgenic and precise molecular biology technologies into the research armamentarium has opened a wide range of additional possibilities for direct involvement of individual isoforms in the insulin signaling cascade. As we hope to discuss within the context of this review, whereas many of the long sought-after answers to specific questions are not yet clear, major advances have been made in our understanding of precise roles for individual PKC isoforms in mediation of insulin effects. In this review, in which we shall focus our attention on isoforms in the conventional and novel categories, a clear case will be made to show that these isoforms are not only expressed but are importantly involved in regulation of insulin metabolic effects.
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Weigert C, Hennige AM, Lehmann R, Brodbeck K, Baumgartner F, Schaüble M, Häring HU, Schleicher ED. Direct cross-talk of interleukin-6 and insulin signal transduction via insulin receptor substrate-1 in skeletal muscle cells. J Biol Chem 2006; 281:7060-7. [PMID: 16418171 DOI: 10.1074/jbc.m509782200] [Citation(s) in RCA: 96] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The exercise-induced interleukin (IL)-6 production and secretion within skeletal muscle fibers has raised the question of a putative tissue-specific function of IL-6 in the energy metabolism of the muscle during and after the exercise. In the present study, we followed the hypothesis that IL-6 signaling may directly interact with insulin receptor substrate (IRS)-1, a keystone in the insulin signaling cascade. We showed that IL-6 induces a rapid recruitment of IRS-1 to the IL-6 receptor complex in cultured skeletal muscle cells. Moreover, IL-6 induced a rapid and transient phosphorylation of Ser-318 of IRS-1 in muscle cells and in muscle tissue, but not in the liver of IL-6-treated mice, probably via the IL-6-induced co-recruitment of protein kinase C-delta. This Ser-318 phosphorylation improved insulin-stimulated Akt phosphorylation and glucose uptake in myotubes since transfection with an IRS-1/Glu-318 mutant simulating a permanent phospho-Ser-318 modification increased Akt phosphorylation and glucose uptake. Noteworthily, two inhibitory mechanisms of IL-6 on insulin action, phosphorylation of the inhibitory Ser-307 residue of IRS-1 and induction of SOCS-3 expression, were only found in liver but not in muscle of IL-6-treated mice. Thus, the data provided evidence for a possible molecular mechanism of the physiological metabolic effects of IL-6 in skeletal muscle, thereby exerting short term beneficial effects on insulin action.
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Affiliation(s)
- Cora Weigert
- Department of Internal Medicine, Division of Endocrinology, Metabolism, Pathobiochemistry and Clinical Chemistry, University of Tübingen, Otfried-Müller-Strasse 10, D-72076 Germany.
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