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Hepatocyte phosphatase DUSP22 mitigates NASH-HCC progression by targeting FAK. Nat Commun 2022; 13:5945. [PMID: 36209205 PMCID: PMC9547917 DOI: 10.1038/s41467-022-33493-5] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2021] [Accepted: 09/21/2022] [Indexed: 11/08/2022] Open
Abstract
Nonalcoholic steatohepatitis (NASH), a common clinical disease, is becoming a leading cause of hepatocellular carcinoma (HCC). Dual specificity phosphatase 22 (DUSP22, also known as JKAP or JSP-1) expressed in numerous tissues plays essential biological functions in immune responses and tumor growth. However, the effects of DUSP22 on NASH still remain unknown. Here, we find a significant decrease of DUSP22 expression in human and murine fatty liver, which is mediated by reactive oxygen species (ROS) generation. Hepatic-specific DUSP22 deletion particularly exacerbates lipid deposition, inflammatory response and fibrosis in liver, facilitating NASH and non-alcoholic fatty liver disease (NAFLD)-associated HCC progression. In contrast, transgenic over-expression, lentivirus or adeno-associated virus (AAV)-mediated DUSP22 gene therapy substantially inhibit NASH-related phenotypes and HCC development in mice. We provide mechanistic evidence that DUSP22 directly interacts with focal adhesion kinase (FAK) and restrains its phosphorylation at Tyr397 (Y397) and Y576 + Y577 residues, subsequently prohibiting downstream activation of extracellular signal-regulated kinase 1/2 (ERK1/2) and nuclear factor-κB (NF-κB) cascades. The binding of DUSP22 to FAK and the dephosphorylation of FAK are indispensable for DUSP22-meliorated NASH progression. Collectively, our findings identify DUSP22 as a key suppressor of NASH-HCC, and underscore the DUSP22-FAK axis as a promising therapeutic target for treatment of the disease.
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2
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Yuan Y, Zhu C, Wang Y, Sun J, Feng J, Ma Z, Li P, Peng W, Yin C, Xu G, Xu P, Jiang Y, Jiang Q, Shu G. α-Ketoglutaric acid ameliorates hyperglycemia in diabetes by inhibiting hepatic gluconeogenesis via serpina1e signaling. SCIENCE ADVANCES 2022; 8:eabn2879. [PMID: 35507647 PMCID: PMC9067931 DOI: 10.1126/sciadv.abn2879] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/17/2021] [Accepted: 03/17/2022] [Indexed: 05/13/2023]
Abstract
Previously, we found that α-ketoglutaric acid (AKG) stimulates muscle hypertrophy and fat loss through 2-oxoglutarate receptor 1 (OXGR1). Here, we demonstrated the beneficial effects of AKG on glucose homeostasis in a diet-induced obesity (DIO) mouse model, which are independent of OXGR1. We also showed that AKG effectively decreased blood glucose and hepatic gluconeogenesis in DIO mice. By using transcriptomic and liver-specific serpina1e deletion mouse model, we further demonstrated that liver serpina1e is required for the inhibitory effects of AKG on hepatic gluconeogenesis. Mechanistically, we supported that extracellular AKG binds with a purinergic receptor, P2RX4, to initiate the solute carrier family 25 member 11 (SLC25A11)-dependent nucleus translocation of intracellular AKG and subsequently induces demethylation of lysine 27 on histone 3 (H3K27) in the seprina1e promoter region to decrease hepatic gluconeogenesis. Collectively, these findings reveal an unexpected mechanism for control of hepatic gluconeogenesis using circulating AKG as a signal molecule.
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Affiliation(s)
- Yexian Yuan
- Guangdong Laboratory of Lingnan Modern Agriculture and Guangdong Province Key Laboratory of Animal Nutritional Regulation, National Engineering Research Center for Breeding Swine Industry, College of Animal Science, South China Agricultural University, 483 Wushan Road, Tianhe District, Guangzhou, Guangdong 510642, China
| | - Canjun Zhu
- Guangdong Laboratory of Lingnan Modern Agriculture and Guangdong Province Key Laboratory of Animal Nutritional Regulation, National Engineering Research Center for Breeding Swine Industry, College of Animal Science, South China Agricultural University, 483 Wushan Road, Tianhe District, Guangzhou, Guangdong 510642, China
| | - Yongliang Wang
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Shaanxi Province, College of Animal Science and Technology, Northwest A&F University, Yangling, Shaanxi, China
| | - Jia Sun
- Department of Endocrinology, Zhujiang Hospital, Southern Medical University, Guangzhou 510280, China
| | - Jinlong Feng
- Guangdong Laboratory of Lingnan Modern Agriculture and Guangdong Province Key Laboratory of Animal Nutritional Regulation, National Engineering Research Center for Breeding Swine Industry, College of Animal Science, South China Agricultural University, 483 Wushan Road, Tianhe District, Guangzhou, Guangdong 510642, China
| | - Zewei Ma
- Guangdong Laboratory of Lingnan Modern Agriculture and Guangdong Province Key Laboratory of Animal Nutritional Regulation, National Engineering Research Center for Breeding Swine Industry, College of Animal Science, South China Agricultural University, 483 Wushan Road, Tianhe District, Guangzhou, Guangdong 510642, China
| | - Penglin Li
- Guangdong Laboratory of Lingnan Modern Agriculture and Guangdong Province Key Laboratory of Animal Nutritional Regulation, National Engineering Research Center for Breeding Swine Industry, College of Animal Science, South China Agricultural University, 483 Wushan Road, Tianhe District, Guangzhou, Guangdong 510642, China
| | - Wentong Peng
- Guangdong Laboratory of Lingnan Modern Agriculture and Guangdong Province Key Laboratory of Animal Nutritional Regulation, National Engineering Research Center for Breeding Swine Industry, College of Animal Science, South China Agricultural University, 483 Wushan Road, Tianhe District, Guangzhou, Guangdong 510642, China
| | - Cong Yin
- Guangdong Laboratory of Lingnan Modern Agriculture and Guangdong Province Key Laboratory of Animal Nutritional Regulation, National Engineering Research Center for Breeding Swine Industry, College of Animal Science, South China Agricultural University, 483 Wushan Road, Tianhe District, Guangzhou, Guangdong 510642, China
| | - Guli Xu
- Guangdong Laboratory of Lingnan Modern Agriculture and Guangdong Province Key Laboratory of Animal Nutritional Regulation, National Engineering Research Center for Breeding Swine Industry, College of Animal Science, South China Agricultural University, 483 Wushan Road, Tianhe District, Guangzhou, Guangdong 510642, China
| | - Pingwen Xu
- Division of Endocrinology, Department of Medicine, The University of Illinois at Chicago, Chicago, IL 60612, USA
| | - Yuwei Jiang
- Department of Physiology and Biophysics, The University of Illinois at Chicago, Chicago, IL 60612, USA
| | - Qingyan Jiang
- Guangdong Laboratory of Lingnan Modern Agriculture and Guangdong Province Key Laboratory of Animal Nutritional Regulation, National Engineering Research Center for Breeding Swine Industry, College of Animal Science, South China Agricultural University, 483 Wushan Road, Tianhe District, Guangzhou, Guangdong 510642, China
| | - Gang Shu
- Guangdong Laboratory of Lingnan Modern Agriculture and Guangdong Province Key Laboratory of Animal Nutritional Regulation, National Engineering Research Center for Breeding Swine Industry, College of Animal Science, South China Agricultural University, 483 Wushan Road, Tianhe District, Guangzhou, Guangdong 510642, China
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3
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Chen HJ, Yan XY, Sun A, Zhang L, Zhang J, Yan YE. High-Fat-Diet-Induced Extracellular Matrix Deposition Regulates Integrin - FAK Signals in Adipose Tissue to Promote Obesity. Mol Nutr Food Res 2022; 66:e2101088. [PMID: 35106921 DOI: 10.1002/mnfr.202101088] [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: 11/29/2021] [Revised: 01/24/2022] [Indexed: 11/06/2022]
Abstract
SCOPE High-fat-diet (HFD) is an important factor in obesity. Extracellular matrix (ECM) regulates white adipose tissue (WAT), but its mechanism is unknown. METHODS AND RESULTS We used three models- HFD-fed mice, human with obesity and 3T3-L1 adipocytes with oleic acid (OA)/macromolecular crowders (MMC) treatment. We observed glucose and lipids metabolic disorders, increased collagen I/IV and LAMA2/4 and upregulated integrins (ITGA1/ITGA7) - FAK - JNK/ERK1/2 signals in obese WAT from mice and human. The upregulation of ECM - integrin - FAK signals was stronger in subcutaneous WAT than in visceral WAT of mice, but these results were reversed in human. In vitro, oleic acid (OA) promoted lipid accumulation and upregulated collagen IV, LAMA4 and p-JNK. MMC was used to induce ECM deposition in adipocytes. MMC promoted adipocyte differentiation and integrins - FAK - JNK/ERK1/2 signals. When FAK phosphorylation was inhibited, downstream p-JNK decreased. Inhibition of FAK phosphorylation reduced adipocyte differentiation, but MMC partially reversed this effect. CONCLUSION HFD-induced ECM deposition, whose signals were transmitted into adipocytes through upregulating ITGA1/ITGA7, activated the phosphorylation of intracellular FAK - JNK/ERK1/2 signals, and promoted adipogenesis in WAT. This mechanism provides novel therapeutic targets to treat obesity. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Hui-Jian Chen
- Department of Pharmacology, Wuhan University School of Basic Medical Sciences, Wuhan, 430071, China
| | - Xi-Yue Yan
- Department of Pharmacology, Wuhan University School of Basic Medical Sciences, Wuhan, 430071, China
| | - Ao Sun
- Department of Pharmacology, Wuhan University School of Basic Medical Sciences, Wuhan, 430071, China
| | - Li Zhang
- Demonstration Center for Experimental Basic Medicine Education, Wuhan University School of Basic Medical Sciences, Wuhan, 430071, China
| | - Jing Zhang
- Center for Animal Experiment/Animal Biosafety Level 3 Laboratory, Wuhan University, Wuhan, 430071, China
| | - You-E Yan
- Department of Pharmacology, Wuhan University School of Basic Medical Sciences, Wuhan, 430071, China
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4
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Martín-Estal I, Castorena-Torres F. Gestational Diabetes Mellitus and Energy-Dense Diet: What Is the Role of the Insulin/IGF Axis? Front Endocrinol (Lausanne) 2022; 13:916042. [PMID: 35813659 PMCID: PMC9259869 DOI: 10.3389/fendo.2022.916042] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/08/2022] [Accepted: 05/24/2022] [Indexed: 01/02/2023] Open
Abstract
Gestational diabetes mellitus (GDM), is one of the most important pregnancy complications affecting approximately 15% of pregnant women. It is related to several gestational adverse outcomes in the fetus, e.g., macrosomia, shoulder dystocia, stillbirth, neonatal hypoglycemia, and respiratory distress. Women with GDM have a high risk of developing type 2 diabetes in the future. The pathogenesis of GDM is not completely understood; nevertheless, two factors could contribute to its development: β-cell dysfunction and failure in insulin secretion in response to insulin resistance induced by gestation. Both processes, together with the physiological activities of the insulin-like growth factors (IGFs), play a crucial role in glucose transport to the fetus and hence, fetal growth and development. IGFs (both IGF-1 and IGF-2) and their binding proteins (IGFBPs) regulate glucose metabolism and insulin sensitivity. Maternal nutritional status determines the health of the newborn, as it has substantial effects on fetal growth and development. Maternal obesity and an energy-dense diet can cause an increase in insulin and IGF-1 serum levels, producing metabolic disorders, such as insulin resistance, GDM, and high birth weight (> 4,000 g) due to a higher level of body fat. In this way, in GDM pregnancies there is an increase in IGF-1 and IGF-2 serum levels, and a decrease in IGFBP-1 and 4 serum levels, suggesting the crucial role of the insulin/IGF system in this gestational outcome. Here, the present review tries to elucidate the role that energy-dense diets and the insulin/IGF-1 signaling pathway perform in GDM pregnancies.
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5
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Zandi Shafagh R, Shen JX, Youhanna S, Guo W, Lauschke VM, van der Wijngaart W, Haraldsson T. Facile Nanoimprinting of Robust High-Aspect-Ratio Nanostructures for Human Cell Biomechanics. ACS APPLIED BIO MATERIALS 2020; 3:8757-8767. [PMID: 35019647 DOI: 10.1021/acsabm.0c01087] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
High-aspect-ratio and hierarchically nanostructured surfaces are common in nature. Synthetic variants are of interest for their specific chemical, mechanic, electric, photonic, or biologic properties but are cumbersome in fabrication or suffer from structural collapse. Here, we replicated and directly biofunctionalized robust, large-area, and high-aspect-ratio nanostructures by nanoimprint lithography of an off-stoichiometric thiol-ene-epoxy polymer. We structured-in a single-step process-dense arrays of pillars with a diameter as low as 100 nm and an aspect ratio of 7.2; holes with a diameter of 70 nm and an aspect ratio of >20; and complex hierarchically layered structures, all with minimal collapse and defectivity. We show that the nanopillar arrays alter mechanosensing of human hepatic cells and provide precise spatial control of cell attachment. We speculate that our results can enable the widespread use of high-aspect-ratio nanotopograhy applications in mechanics, optics, and biomedicine.
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Affiliation(s)
- Reza Zandi Shafagh
- Department of Physiology and Pharmacology, Karolinska Institutet, 171 77 Stockholm, Sweden.,Division of Micro- and Nanosystems, KTH Royal Institute of Technology, 100 44 Stockholm, Sweden
| | - Joanne X Shen
- Department of Physiology and Pharmacology, Karolinska Institutet, 171 77 Stockholm, Sweden
| | - Sonia Youhanna
- Department of Physiology and Pharmacology, Karolinska Institutet, 171 77 Stockholm, Sweden
| | - Weijin Guo
- Division of Micro- and Nanosystems, KTH Royal Institute of Technology, 100 44 Stockholm, Sweden
| | - Volker M Lauschke
- Department of Physiology and Pharmacology, Karolinska Institutet, 171 77 Stockholm, Sweden
| | | | - Tommy Haraldsson
- Division of Micro- and Nanosystems, KTH Royal Institute of Technology, 100 44 Stockholm, Sweden
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Vornhagen J, Armistead B, Santana-Ufret V, Gendrin C, Merillat S, Coleman M, Quach P, Boldenow E, Alishetti V, Leonhard-Melief C, Ngo LY, Whidbey C, Doran KS, Curtis C, Waldorf KMA, Nance E, Rajagopal L. Group B streptococcus exploits vaginal epithelial exfoliation for ascending infection. J Clin Invest 2018; 128:1985-1999. [PMID: 29629904 DOI: 10.1172/jci97043] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2017] [Accepted: 02/27/2018] [Indexed: 12/11/2022] Open
Abstract
Thirteen percent of pregnancies result in preterm birth or stillbirth, accounting for fifteen million preterm births and three and a half million deaths annually. A significant cause of these adverse pregnancy outcomes is in utero infection by vaginal microorganisms. To establish an in utero infection, vaginal microbes enter the uterus by ascending infection; however, the mechanisms by which this occurs are unknown. Using both in vitro and murine models of vaginal colonization and ascending infection, we demonstrate how a vaginal microbe, group B streptococcus (GBS), which is frequently associated with adverse pregnancy outcomes, uses vaginal exfoliation for ascending infection. GBS induces vaginal epithelial exfoliation by activation of integrin and β-catenin signaling. However, exfoliation did not diminish GBS vaginal colonization as reported for other vaginal microbes. Rather, vaginal exfoliation increased bacterial dissemination and ascending GBS infection, and abrogation of exfoliation reduced ascending infection and improved pregnancy outcomes. Thus, for some vaginal bacteria, exfoliation promotes ascending infection rather than preventing colonization. Our study provides insight into mechanisms of ascending infection by vaginal microbes.
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Affiliation(s)
- Jay Vornhagen
- Department of Global Health, University of Washington, Seattle, Washington, USA.,Center for Global Infectious Disease Research, Seattle Children's Research Institute, Seattle, Washington, USA
| | - Blair Armistead
- Department of Global Health, University of Washington, Seattle, Washington, USA.,Center for Global Infectious Disease Research, Seattle Children's Research Institute, Seattle, Washington, USA
| | - Verónica Santana-Ufret
- Center for Global Infectious Disease Research, Seattle Children's Research Institute, Seattle, Washington, USA
| | - Claire Gendrin
- Center for Global Infectious Disease Research, Seattle Children's Research Institute, Seattle, Washington, USA
| | - Sean Merillat
- Center for Global Infectious Disease Research, Seattle Children's Research Institute, Seattle, Washington, USA
| | - Michelle Coleman
- Center for Global Infectious Disease Research, Seattle Children's Research Institute, Seattle, Washington, USA.,Department of Pediatrics, University of Washington, Seattle, Washington, USA
| | - Phoenicia Quach
- Center for Global Infectious Disease Research, Seattle Children's Research Institute, Seattle, Washington, USA
| | - Erica Boldenow
- Center for Global Infectious Disease Research, Seattle Children's Research Institute, Seattle, Washington, USA.,Department of Pediatrics, University of Washington, Seattle, Washington, USA
| | - Varchita Alishetti
- Center for Global Infectious Disease Research, Seattle Children's Research Institute, Seattle, Washington, USA
| | | | - Lisa Y Ngo
- Center for Global Infectious Disease Research, Seattle Children's Research Institute, Seattle, Washington, USA
| | - Christopher Whidbey
- Department of Global Health, University of Washington, Seattle, Washington, USA.,Center for Global Infectious Disease Research, Seattle Children's Research Institute, Seattle, Washington, USA
| | - Kelly S Doran
- Department of Microbiology and Immunology, University of Colorado Denver, Aurora, Colorado, USA
| | | | - Kristina M Adams Waldorf
- Department of Global Health, University of Washington, Seattle, Washington, USA.,Department of Obstetrics and Gynecology, and.,Center for Innate Immunity and Immune Disease, University of Washington, Seattle, Washington, USA.,Sahlgrenska Academy, Gothenburg University, Gothenburg, Sweden
| | | | - Lakshmi Rajagopal
- Department of Global Health, University of Washington, Seattle, Washington, USA.,Center for Global Infectious Disease Research, Seattle Children's Research Institute, Seattle, Washington, USA.,Department of Pediatrics, University of Washington, Seattle, Washington, USA.,Center for Innate Immunity and Immune Disease, University of Washington, Seattle, Washington, USA
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7
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The Influence of Metabolic Syndrome and Sex on the DNA Methylome in Schizophrenia. Int J Genomics 2018; 2018:8076397. [PMID: 29850476 PMCID: PMC5903198 DOI: 10.1155/2018/8076397] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2017] [Accepted: 02/25/2018] [Indexed: 02/06/2023] Open
Abstract
Introduction The mechanism by which metabolic syndrome occurs in schizophrenia is not completely known; however, previous work suggests that changes in DNA methylation may be involved which is further influenced by sex. Within this study, the DNA methylome was profiled to identify altered methylation associated with metabolic syndrome in a schizophrenia population on atypical antipsychotics. Methods Peripheral blood from schizophrenia subjects was utilized for DNA methylation analyses. Discovery analyses (n = 96) were performed using an epigenome-wide analysis on the Illumina HumanMethylation450K BeadChip based on metabolic syndrome diagnosis. A secondary discovery analysis was conducted based on sex. The top hits from the discovery analyses were assessed in an additional validation set (n = 166) using site-specific methylation pyrosequencing. Results A significant increase in CDH22 gene methylation in subjects with metabolic syndrome was identified in the overall sample. Additionally, differential methylation was found within the MAP3K13 gene in females and the CCDC8 gene within males. Significant differences in methylation were again observed for the CDH22 and MAP3K13 genes, but not CCDC8, in the validation sample set. Conclusions This study provides preliminary evidence that DNA methylation may be associated with metabolic syndrome and sex in schizophrenia.
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8
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Kim J, Bilder D, Neufeld TP. Mechanical stress regulates insulin sensitivity through integrin-dependent control of insulin receptor localization. Genes Dev 2018; 32:156-164. [PMID: 29440263 PMCID: PMC5830928 DOI: 10.1101/gad.305870.117] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2017] [Accepted: 01/02/2018] [Indexed: 12/22/2022]
Abstract
Kim et al. show that insulin signaling in Drosophila adipocytes is abolished in the absence of physical activity and mechanical stress. The insulin receptor and downstream components are recruited to the plasma membrane upon stress sensing mediated by integrins. Insulin resistance, the failure to activate insulin signaling in the presence of ligand, leads to metabolic diseases, including type 2 diabetes. Physical activity and mechanical stress have been shown to protect against insulin resistance, but the molecular mechanisms remain unclear. Here, we address this relationship in the Drosophila larval fat body, an insulin-sensitive organ analogous to vertebrate adipose tissue and livers. We found that insulin signaling in Drosophila fat body cells is abolished in the absence of physical activity and mechanical stress even when excess insulin is present. Physical movement is required for insulin sensitivity in both intact larvae and fat bodies cultured ex vivo. Interestingly, the insulin receptor and other downstream components are recruited to the plasma membrane in response to mechanical stress, and this membrane localization is rapidly lost upon disruption of larval or tissue movement. Sensing of mechanical stimuli is mediated in part by integrins, whose activation is necessary and sufficient for mechanical stress-dependent insulin signaling. Insulin resistance develops naturally during the transition from the active larval stage to the immotile pupal stage, suggesting that regulation of insulin sensitivity by mechanical stress may help coordinate developmental programming with metabolism.
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Affiliation(s)
- Jung Kim
- Department of Genetics, Cell Biology, and Development, University of Minnesota, Minneapolis, Minnesota 55455, USA.,Department of Molecular and Cell Biology, University of California at Berkeley, Berkeley, California 94720, USA
| | - David Bilder
- Department of Molecular and Cell Biology, University of California at Berkeley, Berkeley, California 94720, USA
| | - Thomas P Neufeld
- Department of Genetics, Cell Biology, and Development, University of Minnesota, Minneapolis, Minnesota 55455, USA
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9
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Lassiter DG, Nylén C, Sjögren RJO, Chibalin AV, Wallberg-Henriksson H, Näslund E, Krook A, Zierath JR. FAK tyrosine phosphorylation is regulated by AMPK and controls metabolism in human skeletal muscle. Diabetologia 2018; 61:424-432. [PMID: 29022062 PMCID: PMC6449061 DOI: 10.1007/s00125-017-4451-8] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/21/2017] [Accepted: 08/11/2017] [Indexed: 01/28/2023]
Abstract
AIMS/HYPOTHESIS Insulin-mediated signals and AMP-activated protein kinase (AMPK)-mediated signals are activated in response to physiological conditions that represent energy abundance and shortage, respectively. Focal adhesion kinase (FAK) is implicated in insulin signalling and cancer progression in various non-muscle cell types and plays a regulatory role during skeletal muscle differentiation. The role of FAK in skeletal muscle in relation to insulin stimulation or AMPK activation is unknown. We examined the effects of insulin or AMPK activation on FAK phosphorylation in human skeletal muscle and the direct role of FAK on glucose and lipid metabolism. We hypothesised that insulin treatment and AMPK activation would have opposing effects on FAK phosphorylation and that gene silencing of FAK would alter metabolism. METHODS Human muscle was treated with insulin or the AMPK-activating compound 5-aminoimadazole-4-carboxamide ribonucleotide (AICAR) to determine FAK phosphorylation and glucose transport. Primary human skeletal muscle cells were used to study the effects of insulin or AICAR treatment on FAK signalling during serum starvation, as well as to determine the metabolic consequences of silencing the FAK gene, PTK2. RESULTS AMPK activation reduced tyrosine phosphorylation of FAK in skeletal muscle. AICAR reduced p-FAKY397 in isolated human skeletal muscle and cultured myotubes. Insulin stimulation did not alter FAK phosphorylation. Serum starvation increased AMPK activation, as demonstrated by increased p-ACCS222, concomitant with reduced p-FAKY397. FAK signalling was reduced owing to serum starvation and AICAR treatment as demonstrated by reduced p-paxillinY118. Silencing PTK2 in primary human skeletal muscle cells increased palmitate oxidation and reduced glycogen synthesis. CONCLUSIONS/INTERPRETATION AMPK regulates FAK signalling in skeletal muscle. Moreover, siRNA-mediated FAK knockdown enhances lipid oxidation while impairing glycogen synthesis in skeletal muscle. Further exploration of the interaction between AMPK and FAK may lead to novel therapeutic strategies for diabetes and other chronic conditions associated with an altered metabolic homeostasis.
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Affiliation(s)
- David G Lassiter
- Department of Molecular Medicine and Surgery, Section for Integrative Physiology, Karolinska Institutet, von Eulers väg 4a, IV, SE-171 65, Stockholm, Sweden
| | - Carolina Nylén
- Department of Molecular Medicine and Surgery, Section for Integrative Physiology, Karolinska Institutet, von Eulers väg 4a, IV, SE-171 65, Stockholm, Sweden
| | - Rasmus J O Sjögren
- Department of Molecular Medicine and Surgery, Section for Integrative Physiology, Karolinska Institutet, von Eulers väg 4a, IV, SE-171 65, Stockholm, Sweden
| | - Alexander V Chibalin
- Department of Molecular Medicine and Surgery, Section for Integrative Physiology, Karolinska Institutet, von Eulers väg 4a, IV, SE-171 65, Stockholm, Sweden
| | | | - Erik Näslund
- Division of Surgery, Department of Clinical Sciences, Danderyd Hospital, Karolinska Institutet, Stockholm, Sweden
| | - Anna Krook
- Department of Physiology and Pharmacology, Integrative Physiology, Karolinska Institutet, Stockholm, Sweden
| | - Juleen R Zierath
- Department of Molecular Medicine and Surgery, Section for Integrative Physiology, Karolinska Institutet, von Eulers väg 4a, IV, SE-171 65, Stockholm, Sweden.
- Department of Physiology and Pharmacology, Integrative Physiology, Karolinska Institutet, Stockholm, Sweden.
- Section of Integrative Physiology, The Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Science, University of Copenhagen, Copenhagen, Denmark.
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10
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Williams AS, Trefts E, Lantier L, Grueter CA, Bracy DP, James FD, Pozzi A, Zent R, Wasserman DH. Integrin-Linked Kinase Is Necessary for the Development of Diet-Induced Hepatic Insulin Resistance. Diabetes 2017; 66:325-334. [PMID: 27899483 PMCID: PMC5248997 DOI: 10.2337/db16-0484] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/15/2016] [Accepted: 11/17/2016] [Indexed: 12/17/2022]
Abstract
The liver extracellular matrix (ECM) expands with high-fat (HF) feeding. This finding led us to address whether receptors for the ECM, integrins, are key to the development of diet-induced hepatic insulin resistance. Integrin-linked kinase (ILK) is a downstream integrin signaling molecule involved in multiple hepatic processes, including those related to differentiation, wound healing, and metabolism. We tested the hypothesis that deletion of ILK in mice on an HF diet would disrupt the ECM-integrin signaling axis, thereby preventing the transformation into the insulin-resistant liver. To determine the role of ILK in hepatic insulin action in vivo, male C57BL/6J ILKlox/lox mice were crossed with Albcre mice to produce a hepatocyte-specific ILK deletion (ILKlox/loxAlbcre). Results from this study show that hepatic ILK deletion has no effect on insulin action in lean mice but sensitizes the liver to insulin during the challenge of HF feeding. This effect corresponds to changes in the expression and activation of key insulin signaling pathways as well as a greater capacity for hepatic mitochondrial glucose oxidation. This demonstrates that ILK contributes to hepatic insulin resistance and highlights the previously undefined role of integrin signaling in the pathogenesis of diet-induced hepatic insulin resistance.
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Affiliation(s)
- Ashley S Williams
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN
| | - Elijah Trefts
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN
| | - Louise Lantier
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN
- Mouse Metabolic Phenotyping Center, Vanderbilt University, Nashville, TN
| | - Carrie A Grueter
- Department of Anesthesiology, Vanderbilt University, Nashville, TN
| | - Deanna P Bracy
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN
| | - Freyja D James
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN
| | - Ambra Pozzi
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN
- Division of Nephrology, Department of Medicine, Vanderbilt University, Nashville, TN
- Department of Medicine, Veteran Affairs, Nashville, TN
| | - Roy Zent
- Division of Nephrology, Department of Medicine, Vanderbilt University, Nashville, TN
- Department of Medicine, Veteran Affairs, Nashville, TN
| | - David H Wasserman
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN
- Mouse Metabolic Phenotyping Center, Vanderbilt University, Nashville, TN
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11
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Moncayo G, Lin D, McCarthy MT, Watson AA, O'Callaghan CA. MICA Expression Is Regulated by Cell Adhesion and Contact in a FAK/Src-Dependent Manner. Front Immunol 2017; 7:687. [PMID: 28154561 PMCID: PMC5243850 DOI: 10.3389/fimmu.2016.00687] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2016] [Accepted: 12/23/2016] [Indexed: 11/13/2022] Open
Abstract
MICA is a major ligand for the NKG2D immune receptor, which plays a key role in activating natural killer (NK) cells and cytotoxic T cells. We analyzed NKG2D ligand expression on a range of cell types and could demonstrate that MICA expression levels were closely linked to cellular growth mode. While the expression of other NKG2D ligands was largely independent of cell growth mode, MICA expression was mainly found on cells cultured as adherent cells. In addition, MICA surface expression was reduced through increase in cell-cell contact or loss of cell-matrix adherence. Furthermore, we found that the reduction in MICA expression was modulated by focal adhesion kinase (FAK)/Src signaling and associated with increased susceptibility to NK cell-mediated killing. While the mechanisms of tumor immune evasion are not fully understood, the reduction of MICA expression following loss of attachment poises a potential way by which metastasizing tumor cells avoid immune detection. The role of FAK/Src in this process indicates a potential therapeutic approach to modulate MICA expression and immune recognition of tumor cells during metastasis.
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Affiliation(s)
- Gerald Moncayo
- Henry Wellcome Building for Molecular Physiology, University of Oxford , Oxford , UK
| | - Da Lin
- Henry Wellcome Building for Molecular Physiology, University of Oxford , Oxford , UK
| | - Michael T McCarthy
- Henry Wellcome Building for Molecular Physiology, University of Oxford , Oxford , UK
| | - Aleksandra A Watson
- Henry Wellcome Building for Molecular Physiology, University of Oxford , Oxford , UK
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12
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Gao C, Chen G, Kuan SF, Zhang DH, Schlaepfer DD, Hu J. FAK/PYK2 promotes the Wnt/β-catenin pathway and intestinal tumorigenesis by phosphorylating GSK3β. eLife 2015; 4. [PMID: 26274564 PMCID: PMC4558782 DOI: 10.7554/elife.10072] [Citation(s) in RCA: 88] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2015] [Accepted: 08/11/2015] [Indexed: 12/16/2022] Open
Abstract
Aberrant activation of Wnt/β-catenin signaling plays an unequivocal role in colorectal cancer, but identification of effective Wnt inhibitors for use in cancer remains a tremendous challenge. New insights into the regulation of this pathway could reveal new therapeutic point of intervention, therefore are greatly needed. Here we report a novel FAK/PYK2/GSK3β(Y216)/β-catenin regulation axis: FAK and PYK2, elevated in adenomas in APC(min/+) mice and in human colorectal cancer tissues, functioned redundantly to promote the Wnt/β-catenin pathway by phosphorylating GSK3β(Y216) to reinforce pathway output-β-catenin accumulation and intestinal tumorigenesis. We previously showed that Wnt-induced β-catenin accumulation requires Wnt-induced GSK3β/β-TrCP interaction; the current study revealed that phosphorylation of GSK3β(Y216) was a molecular determinant of GSK3β recruitment of β-TrCP. Pharmacological inhibition of FAK/PYK2 suppressed adenoma formation in APC(min/+) mice accompanied with reduced intestinal levels of phospho-GSK3β(Y216) and β-catenin, indicating that FAK/PYK2/GSK3β(Y216) axis is critical for the activation of Wnt/β-catenin signaling in APC driven intestinal tumorigenesis.
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Affiliation(s)
- Chenxi Gao
- Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, United States
| | - Guangming Chen
- Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, United States
| | - Shih-Fan Kuan
- Department of Pathology, University of Pittsburgh School of Medicine, Pittsburgh, United States
| | | | - David D Schlaepfer
- Department of Reproductive Medicine, Moores Cancer Center, University of California, San Diego, San Diego, United States
| | - Jing Hu
- Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, United States
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13
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Williams AS, Kang L, Wasserman DH. The extracellular matrix and insulin resistance. Trends Endocrinol Metab 2015; 26:357-66. [PMID: 26059707 PMCID: PMC4490038 DOI: 10.1016/j.tem.2015.05.006] [Citation(s) in RCA: 141] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/15/2015] [Revised: 05/13/2015] [Accepted: 05/14/2015] [Indexed: 12/14/2022]
Abstract
The extracellular matrix (ECM) is a highly-dynamic compartment that undergoes remodeling as a result of injury and repair. Over the past decade, mounting evidence in humans and rodents suggests that ECM remodeling is associated with diet-induced insulin resistance in several metabolic tissues. In addition, integrin receptors for the ECM have also been implicated in the regulation of insulin action. This review addresses what is currently known about the ECM, integrins, and insulin action in the muscle, liver, and adipose tissue. Understanding how ECM remodeling and integrin signaling regulate insulin action may aid in the development of new therapeutic targets for the treatment of insulin resistance and type 2 diabetes (T2D).
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Affiliation(s)
- Ashley S Williams
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN, USA
| | - Li Kang
- Division of Cardiovascular and Diabetes Medicine, Ninewells Hospital and Medical School, University of Dundee, Dundee, UK
| | - David H Wasserman
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN, USA; Mouse Metabolic Phenotyping Center, Vanderbilt University, Nashville, TN, USA.
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14
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Cao Y, Nimptsch K, Shui IM, Platz EA, Wu K, Pollak MN, Kenfield SA, Stampfer MJ, Giovannucci EL. Prediagnostic plasma IGFBP-1, IGF-1 and risk of prostate cancer. Int J Cancer 2014; 136:2418-26. [PMID: 25348852 DOI: 10.1002/ijc.29295] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2014] [Accepted: 10/20/2014] [Indexed: 11/07/2022]
Abstract
Insulin-like growth factor (IGF)-1 is associated with a higher risk of prostate cancer. IGF-binding protein (IGFBP)-1, a marker for insulin activity, also binds IGF-1 and inhibits its action. Data on IGFBP-1 and prostate cancer risk are sparse and whether the IGF and insulin axes interact to affect prostate cancer carcinogenesis is unknown. We evaluated the independent and joint influence of prediagnostic plasma levels of IGFBP-1 (fasting) and IGF-1 on risk of prostate cancer among 957 cases and 1,021 controls with fasting levels of IGFBP-1 and 1,709 cases and 1,778 controls with IGF-1 nested within the Health Professionals Follow-up Study. Unconditional logistic regression adjusting for matching factors was used to estimate the odds ratio (OR) and 95% confidence interval (CI). Higher prediagnostic fasting IGFBP-1 levels were associated with lower risk of prostate cancer (highest vs. lowest quartile OR = 0.67, 95% CI 0.52-0.86, p(trend) = 0.003), which remained similar after adjusting for IGF-1. Prediagnostic IGF-1 was associated with increased risk of prostate cancer (highest vs. lowest quartile OR = 1.28, 95% CI = 1.05-1.56, p(trend) = 0.01). The associations with each marker were primarily driven by lower-grade and non-advanced prostate cancer. Being low in IGFBP-1 and high in IGF-1 did not confer appreciable additional risk (p(interaction) = 0.42). In summary, prediagnostic fasting IGFBP-1 may influence prostate cancer carcinogenesis. Being low in IGFBP-1 or high in IGF-1 is sufficient to elevate the risk of prostate cancer.
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Affiliation(s)
- Yin Cao
- Department of Nutrition, Harvard School of Public Health, Boston, MA
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15
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Pazienza V, Borghesan M, Mazza T, Sheedfar F, Panebianco C, Williams R, Mazzoccoli G, Andriulli A, Nakanishi T, Vinciguerra M. SIRT1-metabolite binding histone macroH2A1.1 protects hepatocytes against lipid accumulation. Aging (Albany NY) 2014; 6:35-47. [PMID: 24473773 PMCID: PMC3927808 DOI: 10.18632/aging.100632] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Non-alcoholic-fatty-liver-disease (NAFLD) encompasses conditions associated to fat deposition in the liver, which are generally deteriorated during the aging process. MacroH2A1, a variant of histone H2A, is a key transcriptional regulator involved in tumorigenic processes and cell senescence, and featuring two alternatively splicing isoforms, macroH2A1.1 and macroH2A1.2. MacroH2A1.1 binds with high affinity O-acetyl ADP ribose, a small metabolite produced by the reaction catalysed by NAD+-dependent deacetylase SIRT1, whereas macroH2A1.2 is unable to do so. The functional significance of this binding is unknown. We previously reported that the hepatic levels of macroH2A1.1 and macroH2A1.2 are differentially expressed in mice models of NAFLD. Here we show that over-expression of macroH2A1.1, but not of macroH2A1.2, is able to protect hepatocytes against lipid accumulation. MacroH2A1.1 over-expressing cells display ameliorated glucose metabolism, reduced expression of lipidogenic genes and fatty acids content. SIRT1/macroH2A1.1-dependent epigenetic regulation of lipid metabolism may be relevant to NAFLD development.
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Affiliation(s)
- Valerio Pazienza
- Department of Medical Sciences, Gastroenterology Unit, IRCCS "Casa Sollievo della Sofferenza" Hospital, San Giovanni Rotondo, Italy
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16
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Zhang J, Hochwald SN. The role of FAK in tumor metabolism and therapy. Pharmacol Ther 2013; 142:154-63. [PMID: 24333503 DOI: 10.1016/j.pharmthera.2013.12.003] [Citation(s) in RCA: 70] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2013] [Accepted: 11/08/2013] [Indexed: 02/06/2023]
Abstract
Focal adhesion kinase (FAK) plays a vital role in tumor cell proliferation, survival and migration. Altered metabolic pathways fuel rapid tumor growth by accelerating glucose, lipid and glutamine processing. Besides the mitogenic effects of FAK, evidence is accumulating supporting the association between hyper-activated FAK and aberrant metabolism in tumorigenesis. FAK can promote glucose consumption, lipogenesis, and glutamine dependency to promote cancer cell proliferation, motility, and survival. Clinical studies demonstrate that FAK-related alterations of tumor metabolism are associated with increased risk of developing solid tumors. Since FAK contributes to the malignant phenotype, small molecule inhibition of FAK-stimulated bioenergetic and biosynthetic processes can provide a novel approach for therapeutic intervention in tumor growth and invasion.
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Affiliation(s)
- Jianliang Zhang
- Department of Surgical Oncology, Roswell Park Cancer Institute, Elm and Carlton Streets, Buffalo, NY 14263, United States
| | - Steven N Hochwald
- Department of Surgical Oncology, Roswell Park Cancer Institute, Elm and Carlton Streets, Buffalo, NY 14263, United States.
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17
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Deblon N, Bourgoin L, Veyrat-Durebex C, Peyrou M, Vinciguerra M, Caillon A, Maeder C, Fournier M, Montet X, Rohner-Jeanrenaud F, Foti M. Chronic mTOR inhibition by rapamycin induces muscle insulin resistance despite weight loss in rats. Br J Pharmacol 2012; 165:2325-40. [PMID: 22014210 DOI: 10.1111/j.1476-5381.2011.01716.x] [Citation(s) in RCA: 116] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
BACKGROUND AND PURPOSE mTOR inhibitors are currently used as immunosuppressants in transplanted patients and as promising anti-cancer agents. However, new-onset diabetes is a frequent complication occurring in patients treated with mTOR inhibitors such as rapamycin (Sirolimus). Here, we investigated the mechanisms associated with the diabetogenic effects of chronic Sirolimus administration in rats and in in vitro cell cultures. EXPERIMENTAL APPROACH Sirolimus was administered to rats fed either a standard or high-fat diet for 21 days. Metabolic parameters were measured in vivo and in ex vivo tissues. Insulin sensitivity was assessed by glucose tolerance tests and euglycaemic hyperinsulinaemic clamps. Rapamycin effects on glucose metabolism and insulin signalling were further evaluated in cultured myotubes. KEY RESULTS Sirolimus induced a decrease in food intake and concomitant weight loss. It also induced specific fat mass loss that was independent of changes in food intake. Despite these beneficial effects, Sirolimus-treated rats were glucose intolerant, hyperinsulinaemic and hyperglycaemic, but not hyperlipidaemic. The euglycaemic hyperinsulinaemic clamp measurements showed skeletal muscle is a major site of Sirolimus-induced insulin resistance. At the molecular level, long-term Sirolimus administration attenuated glucose uptake and metabolism in skeletal muscle by preventing full insulin-induced Akt activation and altering the expression and translocation of glucose transporters to the plasma membrane. In rats fed a high-fat diet, these metabolic defects were exacerbated, although Sirolimus-treated animals were protected from diet-induced obesity. CONCLUSIONS AND IMPLICATIONS Taken together, our data demonstrate that the diabetogenic effect of chronic rapamycin administration is due to an impaired insulin action on glucose metabolism in skeletal muscles.
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Affiliation(s)
- N Deblon
- Department of Internal Medicine, University of Geneva, Geneva, Switzerland
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18
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Gupta A, Bisht B, Dey CS. Focal adhesion kinase negatively regulates neuronal insulin resistance. Biochim Biophys Acta Mol Basis Dis 2012; 1822:1030-7. [DOI: 10.1016/j.bbadis.2012.02.011] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2011] [Revised: 02/09/2012] [Accepted: 02/10/2012] [Indexed: 12/13/2022]
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19
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Chaves Neto AH, Yano CL, Paredes-Gamero EJ, Machado D, Justo GZ, Peppelenbosch MP, Ferreira CV. Riboflavin and photoproducts in MC3T3-E1 differentiation. Toxicol In Vitro 2010; 24:1911-9. [DOI: 10.1016/j.tiv.2010.07.026] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2010] [Accepted: 07/29/2010] [Indexed: 10/19/2022]
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20
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Paule SG, Nikolovski B, Gray RE, Ludeman JP, Freemantle A, Spark RA, Kerr JB, Ng FM, Zimmet PZ, Myers MA. GHTD-amide: a naturally occurring beta cell-derived peptide with hypoglycemic activity. Peptides 2009; 30:955-61. [PMID: 19162105 DOI: 10.1016/j.peptides.2008.12.022] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/14/2008] [Revised: 12/22/2008] [Accepted: 12/22/2008] [Indexed: 11/30/2022]
Abstract
In the early 1970s, a peptide fraction with insulin potentiating activity was purified from human urine but the identity and origins of the active constituent remained unknown. Here we identify the active component and characterize its origins. The active peptide was identified as an alpha amidated tetrapeptide with the sequence GHTD-amide. The peptide was synthesized and tested for stimulation of glycogen synthesis and insulin potentiation by insulin tolerance testing in insulin-deficient rats, which confirmed GHTD-amide as the active peptide. Tissue localization using a peptide-specific anti-serum and epifluorescent and confocal microscopy showed decoration of pancreatic islets but not other tissues. Confocal microscopy revealed co-localization with insulin and immunogold and electron microscopy showed localization to dense core secretory granules. Consistent with these observations GHTD-amide was found in media conditioned by MIN6 islet beta cells. Sequence database searching found no annotated protein in the human proteome encoding a potential precursor for GHTD-amide. We conclude that the insulin potentiating activity originally described in human urine is attributable to the tetrapeptide GHTD-amide. GHTD-amide is a novel peptide produced by pancreatic beta cells and no precursor protein is present in the annotated human proteome. Stimulation of glycogen synthesis and co-localization with insulin in beta cells suggest that GHTD-amide may play a role in glucose homeostasis by enhancing insulin action and glucose storage in tissues.
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Affiliation(s)
- S G Paule
- Department of Biochemistry and Molecular Biology, Monash University, Wellington Road, Clayton, Victoria, Australia
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21
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Wheatcroft SB, Kearney MT. IGF-dependent and IGF-independent actions of IGF-binding protein-1 and -2: implications for metabolic homeostasis. Trends Endocrinol Metab 2009; 20:153-62. [PMID: 19349193 DOI: 10.1016/j.tem.2009.01.002] [Citation(s) in RCA: 213] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/03/2008] [Revised: 01/05/2009] [Accepted: 01/05/2009] [Indexed: 11/16/2022]
Abstract
Insulin-like growth factor (IGF)-binding proteins (IGFBPs) confer temporospatial regulation to IGF bioactivity. Both stimulatory and inhibitory effects of IGFBPs on IGF actions have been described, and IGF-independent effects of several IGFBPs are emerging. Accumulating evidence indicates important roles for members of the IGFBP family in metabolic homeostasis. For example, IGFBP-1 concentrations fluctuate inversely in response to changes in plasma insulin levels, implicating IGFBP-1 in glucoregulation, and fasting levels of IGFBP-1 predict insulin sensitivity at the population level. IGFBP-2 concentrations reflect long-term insulin sensitivity and are reduced in the presence of obesity. Here, we review the evolving roles of IGFBP-1 and IGFBP-2 in metabolic homeostasis, summarize their effects on IGF bioactivity and explore putative mechanisms by which they might exert IGF-independent cellular actions.
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Affiliation(s)
- Stephen B Wheatcroft
- Division of Cardiovascular & Diabetes Research, Leeds Institute of Genetics, Health & Therapeutics, University of Leeds, Leeds, UK
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22
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Zong H, Bastie CC, Xu J, Fassler R, Campbell KP, Kurland IJ, Pessin JE. Insulin resistance in striated muscle-specific integrin receptor beta1-deficient mice. J Biol Chem 2009; 284:4679-88. [PMID: 19064993 PMCID: PMC2640962 DOI: 10.1074/jbc.m807408200] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2008] [Revised: 12/01/2008] [Indexed: 01/19/2023] Open
Abstract
Integrin receptor plays key roles in mediating both inside-out and outside-in signaling between cells and the extracellular matrix. We have observed that the tissue-specific loss of the integrin beta1 subunit in striated muscle results in a near complete loss of integrin beta1 subunit protein expression concomitant with a loss of talin and to a lesser extent, a reduction in F-actin content. Muscle-specific integrin beta1-deficient mice had no significant difference in food intake, weight gain, fasting glucose, and insulin levels with their littermate controls. However, dynamic analysis of glucose homeostasis using euglycemichyperinsulinemic clamps demonstrated a 44 and 48% reduction of insulin-stimulated glucose infusion rate and glucose clearance, respectively. The whole body insulin resistance resulted from a specific inhibition of skeletal muscle glucose uptake and glycogen synthesis without any significant effect on the insulin suppression of hepatic glucose output or insulin-stimulated glucose uptake in adipose tissue. The reduction in skeletal muscle insulin responsiveness occurred without any change in GLUT4 protein expression levels but was associated with an impairment of the insulin-stimulated protein kinase B/Akt serine 473 phosphorylation but not threonine 308. The inhibition of insulin-stimulated serine 473 phosphorylation occurred concomitantly with a decrease in integrin-linked kinase expression but with no change in the mTOR.Rictor.LST8 complex (mTORC2). These data demonstrate an in vivo crucial role of integrin beta1 signaling events in mediating cross-talk to that of insulin action.
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Affiliation(s)
- Haihong Zong
- Departments of Medicine and Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, New York 10461, USA
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23
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Bisht B, Srinivasan K, Dey CS. In vivo inhibition of focal adhesion kinase causes insulin resistance. J Physiol 2008; 586:3825-37. [PMID: 18587052 DOI: 10.1113/jphysiol.2008.157107] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Focal adhesion kinase (FAK), a non-receptor tyrosine kinase, has recently been implicated in the regulation of insulin resistance in vitro. However, its in vivo validation has not been attempted due to lethality of FAK knockout. Hence, to ascertain the role of FAK in the development of insulin resistance in vivo, we have down-regulated FAK expression by delivering FAK-specific small interfering RNA (siRNA) in mice using hydrodynamic tail vein injection. Here, we show for the first time that FAK silencing (57 +/- 0.05% in muscle and 80 +/- 0.08% in liver) exacerbates insulin signalling and causes hyperglycaemia (251.68 +/- 8.1 mg dl(-1)) and hyperinsulinaemia (3.48 +/- 0.06 ng ml(-1)) in vivo. FAK-silenced animals are less glucose tolerant and have physiological and biochemical parameters similar to that of high fat diet (HFD)-fed insulin-resistant animals. Phosphorylation and expression of insulin receptor substrate 1 (IRS-1) was attenuated by 40.2 +/- 0.03% and 35.2 +/- 0.6% in muscle and 52.3 +/- 0.04% and 40.2 +/- 0.03% in liver in FAK-silenced mice. Akt-Ser473-phosphorylation decreased in muscle and liver (50.3 +/- 0.03% and 70.2 +/- 0.02%, respectively) in FAK-silenced mice. This, in part, explains the mechanism of development of insulin resistance in FAK-silenced mice. The present study provides direct evidence that FAK is a crucial mediator of insulin resistance in vivo. Considering the lethality of FAK gene knockout the approach of this study will provide a new strategy for in vivo inhibition of FAK. Furthermore, the study should certainly motivate chemists to synthesize new chemical entities for FAK activation. This may shed light on new drug development against insulin resistance.
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Affiliation(s)
- Bharti Bisht
- Signal Transduction Research Laboratory, Department of Biotechnology, National Institute of Pharmaceutical Education and Research, Sector 67, S.A.S. Nagar, Punjab 160 062, India
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Hayashida T, Wu MH, Pierce A, Poncelet AC, Varga J, Schnaper HW. MAP-kinase activity necessary for TGFbeta1-stimulated mesangial cell type I collagen expression requires adhesion-dependent phosphorylation of FAK tyrosine 397. J Cell Sci 2008; 120:4230-40. [PMID: 18032789 DOI: 10.1242/jcs.03492] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
The signals mediating transforming growth factor beta (TGFbeta)-stimulated kidney fibrogenesis are poorly understood. We previously reported TGFbeta-stimulated, Smad-mediated collagen production by human kidney mesangial cells, and that ERK MAP kinase activity optimizes collagen expression and enhances phosphorylation of the Smad3 linker region. Furthermore, we showed that disrupting cytoskeletal integrity decreases type I collagen production. Focal adhesion kinase (FAK, PTK2) activity could integrate these findings. Adhesion-dependent FAK Y397 phosphorylation was detected basally, whereas FAK Y925 phosphorylation was TGFbeta1-dependent. By immunocytochemistry, TGFbeta1 stimulated the merging of phosphorylated FAK with the ends of thickening stress fibers. Cells cultured on poly-L-lysine (pLL) to promote integrin-independent attachment spread less than those on control substrate and failed to demonstrate focal adhesion (FA) engagement with F-actin. FAK Y397 phosphorylation and ERK activity were also decreased under these conditions. In cells with decreased FAK Y397 phosphorylation from either plating on pLL or overexpressing a FAK Y397F point mutant, serine phosphorylation of the Smad linker region, but not of the C-terminus, was reduced. Y397F and Y925F FAK point mutants inhibited TGFbeta-induced Elk-Gal activity, but only the Y397F mutant inhibited TGFbeta-stimulated collagen-promoter activity. The inhibition by the Y397F mutant or by culture on pLL was prevented by co-transfection of constitutively active ERK MAP kinase kinase (MEK), suggesting that FAK Y397 phosphorylation promotes collagen expression via ERK MAP kinase activity. Finally, Y397 FAK phosphorylation, and both C-terminal and linker-region Smad3 phosphorylation were detected in murine TGFbeta-dependent kidney fibrosis. Together, these data demonstrate adhesion-dependent FAK phosphorylation promoting TGFbeta-induced responses to regulate collagen production.
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Affiliation(s)
- Tomoko Hayashida
- Division of Kidney Diseases, Department of Pediatrics, The Freinberg School Of Medicine, Northwestern University, Chicago, IL 60611, USA.
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25
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Vinciguerra M, Veyrat-Durebex C, Moukil MA, Rubbia-Brandt L, Rohner-Jeanrenaud F, Foti M. PTEN down-regulation by unsaturated fatty acids triggers hepatic steatosis via an NF-kappaBp65/mTOR-dependent mechanism. Gastroenterology 2008; 134:268-80. [PMID: 18166358 DOI: 10.1053/j.gastro.2007.10.010] [Citation(s) in RCA: 113] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/05/2007] [Accepted: 09/28/2007] [Indexed: 12/13/2022]
Abstract
BACKGROUND & AIMS Phosphatase and tensin homologue deleted on chromosome 10 (PTEN) is a tumor suppressor and a regulator of insulin sensitivity in peripheral tissues. In the liver, PTEN deletion increases insulin sensitivity, but induces steatosis, steatohepatitis, and hepatocellular carcinoma. Here, we investigated the pathophysiologic mechanisms regulating PTEN expression in the liver and the development of steatosis. METHODS PTEN expression was evaluated in the liver of rats and human beings having metabolic syndrome. Signaling pathways regulating PTEN expression and lipid accumulation in hepatocytes were examined in vitro. RESULTS PTEN expression is down-regulated in the liver of rats having steatosis and high plasma levels of fatty acids, as well as in steatotic human livers. Unsaturated fatty acids inhibited PTEN expression in HepG2 cells via activation of a signaling complex formed by the mammalian target of rapamycin (mTOR) and nuclear factor-kappaB (NF-kappaB). Down-regulation of PTEN expression induced steatosis by affecting import, esterification, and extracellular release of fatty acids. CONCLUSIONS Hepatic steatosis can be mediated by alterations of PTEN expression in hepatocytes exposed to high levels of unsaturated fatty acids. Furthermore, our data revealed interaction between mTOR and NF-kappaB, suggesting cross-talk between these 2 pathways.
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Affiliation(s)
- Manlio Vinciguerra
- Department of Cell Physiology and Metabolism, Geneva Medical Faculty, Geneva University Hospital, Switzerland
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26
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Brink TC, Sudheer S, Janke D, Jagodzinska J, Jung M, Adjaye J. The origins of human embryonic stem cells: a biological conundrum. Cells Tissues Organs 2007; 188:9-22. [PMID: 18160822 DOI: 10.1159/000112843] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Human inner cell mass (ICM) cells isolated from in vitro fertilized blastocysts are the progenitor cells used to establish in vitro stable human embryonic stem cells (hESCs) which are pluripotent and self-renew indefinitely. This long-term perpetuation of hESCs in the undifferentiated state is thought to be an in vitro adaptation of the ICM cells. To investigate at the molecular level how hESCs acquired their unique properties, transcriptional profiles of isolated ICM cells and undifferentiated hESCs were compared. We identified 33 genes enriched in the ICM compared to the trophectoderm and hESCs. These genes are involved in signaling cascades (SEMA7A and MAP3K10), cell proliferation (CUZD1 and MS4A7) and chromatin remodeling (H1FOO and HRMT1L4). Furthermore, primordial germ cell-specific genes (SGCA and TEX11) were detected as expressed in the ICM cells and not hESCs. We propose that the transcriptional differences observed between ICM cells and hESCs might be accounted for by adaptive reprogramming events induced by the in vitro culture conditions which are distinct from that of in vitro fertilized blastocysts. hESCs are a distinct cell type lacking in the human embryo but, nonetheless, resemble the ICM in their ability to differentiate into cells representative of the endodermal, ectodermal and mesodermal cell lineages.
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Affiliation(s)
- Thore C Brink
- Department of Vertebrate Genomics (Molecular Embryology and Aging), Max Planck Institute for Molecular Genetics, Berlin, Germany
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Frasca F, Pandini G, Malaguarnera R, Mandarino A, Messina RL, Sciacca L, Belfiore A, Vigneri R. Role of c-Abl in Directing Metabolic versus Mitogenic Effects in Insulin Receptor Signaling. J Biol Chem 2007; 282:26077-88. [PMID: 17620332 DOI: 10.1074/jbc.m705008200] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
c-Abl is a cytoplasmic tyrosine kinase involved in several signal transduction pathways. Here we report that c-Abl is involved also in insulin receptor signaling. Indeed, c-Abl tyrosine kinase is activated upon insulin stimulation. Inhibition of c-Abl tyrosine kinase by STI571 attenuates the effect of insulin on Akt/GSK-3beta phosphorylation and glycogen synthesis, and at the same time, it enhances the effect of insulin on ERK activation, cell proliferation, and migration. This effect of STI571 is specific to c-Abl inhibition, because it does not occur in Abl-null cells and is restored in c-Abl-reconstituted cells. Numerous evidences suggest that focal adhesion kinase (FAK) is involved in mediating this c-Abl effect. First, anti-phosphotyrosine blots indicate that c-Abl tyrosine kinase activation is concomitant with FAK dephosphorylation in response to insulin, whereas c-Abl inhibition is accompanied by FAK phosphorylation in response to insulin, a response similar to that observed with IGF-I. Second, the c-Abl effects on insulin signaling are not observed in cells devoid of FAK (FAK(-/-) cells). Taken together these results suggest that c-Abl activation by insulin, via a modification of FAK response, may play an important role in directing mitogenic versus metabolic insulin receptor signaling.
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Affiliation(s)
- Francesco Frasca
- Endocrinologia, Dipartimento di Medicina Interna e di Medicina Specialistica, Università di Catania, Ospedale Garibaldi, Nesima, 95122 Catania, Italy.
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28
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Calvert VS, Collantes R, Elariny H, Afendy A, Baranova A, Mendoza M, Goodman Z, Liotta LA, Petricoin EF, Younossi ZM. A systems biology approach to the pathogenesis of obesity-related nonalcoholic fatty liver disease using reverse phase protein microarrays for multiplexed cell signaling analysis. Hepatology 2007; 46:166-72. [PMID: 17596878 DOI: 10.1002/hep.21688] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
UNLABELLED Nonalcoholic fatty liver disease (NAFLD) is a common cause of chronic liver disease. Omental adipose tissue, a biologically active organ secreting adipokines and cytokines, may play a role in the development of NAFLD. We tested this hypothesis with reverse-phase protein microarrays (RPA) for multiplexed cell signaling analysis of adipose tissue from patients with NAFLD. Omental adipose tissue was obtained from 99 obese patients. Liver biopsies obtained at the time of surgery were all read by the same hepatopathologist. Adipose tissue was exposed to rapid pressure cycles to extract protein lysates. RPA was used to investigate intracellular signaling. Analysis of 54 different kinase substrates and cell signaling endpoints showed that an insulin signaling pathway is deranged in different locations in NAFLD patients. Furthermore, components of insulin receptor-mediated signaling differentiate most of the conditions on the NAFLD spectrum. For example, PKA (protein kinase A) and AKT/mTOR (protein kinase B/mammalian target of rapamycin) pathway derangement accurately discriminates patients with NASH from those with the non-progressive forms of NAFLD. PKC (protein kinase C) delta, AKT, and SHC phosphorylation changes occur in patients with simple steatosis. Amounts of the FKHR (forkhead factor Foxo1)phosphorylated at S256 residue were significantly correlated with AST/ALT ratio in all morbidly obese patients. Furthermore, amounts of cleaved caspase 9 and pp90RSK S380 were positively correlated in patients with NASH. Specific insulin pathway signaling events are altered in the adipose tissue of patients with NASH compared with patients with nonprogressive forms of NAFLD. CONCLUSION These findings provide evidence for the role of omental fat in the pathogenesis, and potentially, the progression of NAFLD.
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Affiliation(s)
- Valerie S Calvert
- George Mason-Inova Health System's Translational Research Centers, VA, USA
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29
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Bisht B, Goel HL, Dey CS. Focal adhesion kinase regulates insulin resistance in skeletal muscle. Diabetologia 2007; 50:1058-69. [PMID: 17333113 DOI: 10.1007/s00125-007-0591-6] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/31/2006] [Accepted: 10/15/2006] [Indexed: 10/23/2022]
Abstract
AIMS/HYPOTHESIS On the basis of our previous studies, we investigated the possible role of focal adhesion kinase (FAK) in the development of insulin resistance in skeletal muscle, a major organ responsible for insulin-stimulated glucose uptake. MATERIALS AND METHODS Insulin-resistant C2C12 skeletal muscle cells were transfected with FAK wild-type or FAK mutant plasmids, knocked down using small interfering RNA (siRNA), and their effects on the levels and activities of insulin-signalling molecules and on glucose uptake were determined. RESULTS A significant decrease in tyrosine phosphorylation of FAK in insulin-resistant C2C12 cells was observed. A similar decrease was observed in skeletal muscle obtained from insulin-resistant Sprague-Dawley rats fed a high-fat diet. Increased levels of FAK in insulin-resistant C2C12 skeletal muscle cells increased insulin sensitivity and glucose uptake. These effects were reversed by an increase in the level of kinase activity mutant FAK or suppression of endogenous FAK by siRNA. FAK was also found to interact downstream with insulin receptor substrate-1, phosphatidylinositol 3-kinase and protein kinase C and glycogen synthase kinase 3beta, leading to translocation of glucose transporter 4 and resulting in the regulation of glucose uptake. CONCLUSIONS/INTERPRETATION The present study provides strong evidence that the modulation of FAK level regulates the insulin sensitivity of skeletal muscle cells. The results demonstrate a direct role of FAK in insulin-resistant skeletal muscle cells for the first time.
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Affiliation(s)
- B Bisht
- Signal Transduction Research Laboratory, Department of Biotechnology, National Institute of Pharmaceutical Education and Research (NIPER), Sector 67, S.A.S. Nagar, Chandigarh 160062, India
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30
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Jope RS, Yuskaitis CJ, Beurel E. Glycogen synthase kinase-3 (GSK3): inflammation, diseases, and therapeutics. Neurochem Res 2007; 32:577-95. [PMID: 16944320 PMCID: PMC1970866 DOI: 10.1007/s11064-006-9128-5] [Citation(s) in RCA: 594] [Impact Index Per Article: 34.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/25/2006] [Indexed: 12/14/2022]
Abstract
Deciphering what governs inflammation and its effects on tissues is vital for understanding many pathologies. The recent discovery that glycogen synthase kinase-3 (GSK3) promotes inflammation reveals a new component of its well-documented actions in several prevalent diseases which involve inflammation, including mood disorders, Alzheimer's disease, diabetes, and cancer. Involvement in such disparate conditions stems from the widespread influences of GSK3 on many cellular functions, with this review focusing on its regulation of inflammatory processes. GSK3 promotes the production of inflammatory molecules and cell migration, which together make GSK3 a powerful regulator of inflammation, while GSK3 inhibition provides protection from inflammatory conditions in animal models. The involvement of GSK3 and inflammation in these diseases are highlighted. Thus, GSK3 may contribute not only to primary pathologies in these diseases, but also to the associated inflammation, suggesting that GSK3 inhibitors may have multiple effects influencing these conditions.
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Affiliation(s)
- Richard S Jope
- Department of Psychiatry and Behavioral Neurobiology, University of Alabama at Birmingham, Sparks Center 1057, 1720 Seventh Avenue South, Birmingham, AL 35294-0017, USA.
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31
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Huang D, Khoe M, Befekadu M, Chung S, Takata Y, Ilic D, Bryer-Ash M. Focal adhesion kinase mediates cell survival via NF-kappaB and ERK signaling pathways. Am J Physiol Cell Physiol 2006; 292:C1339-52. [PMID: 17135301 DOI: 10.1152/ajpcell.00144.2006] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Focal adhesion kinase (FAK) is important to cellular functions such as proliferation, migration, and survival of anchorage-dependent cells. We investigated the role of FAK in modulating normal cellular responses, specifically cell survival in response to inflammatory stimuli and serum withdrawal, using FAK-knockout (FAK(-/-)) embryonic fibroblasts. FAK(-/-) fibroblasts were more vulnerable to TNF-alpha-induced apoptosis, as measured by terminal deoxynucleotidyl transferase positivity. FAK(-/-) fibroblasts also demonstrated increased procaspase-3 cleavage to p17 subunit, whereas this was undetectable in FAK(+/+) fibroblasts. Insulin receptor substrate-1 expression was completely abolished and NF-kappaB activity was reduced, with a concomitant decrease in abundance of the anti-apoptotic protein Bcl-x(L) in FAK(-/-) cells. Upon serum withdrawal, FAK(+/+) cells exhibited marked attenuation of basal ERK phosphorylation, while FAK(-/-) cells, in contrast, maintained high basal ERK phosphorylation. Moreover, inhibition of ERK phosphorylation potentiated serum withdrawal-induced caspase-3 activity. This was paralleled by increased insulin receptor substrate (IRS)-2 expression in FAK(-/-) cells, although both insulin- and IGF-1-mediated phosphorylation of Akt/PKB and GSK-3 were impaired. This suggests that IRS-2 protects against apoptosis upon serum withdrawal via the ERK signaling pathway. The specific role of FAK to protect cells from apoptosis is regulated by activation and phosphorylation of NF-kappaB and interaction between activated growth factor anti-apoptotic signaling pathways involving both phosphatidylinositol 3-kinase/Akt and MAPK/ERK1/2. We demonstrate that FAK is necessary for upregulation of the anti-apoptotic NF-kappaB response, as well as for normal expression of growth factor signaling proteins. Thus we propose a novel role for FAK in protection from cytokine-mediated apoptosis.
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Affiliation(s)
- Danshan Huang
- West Los Angeles Veterans Administration Medical Center, Los Angeles, CA, USA
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Huang D, Khoe M, Ilic D, Bryer-Ash M. Reduced expression of focal adhesion kinase disrupts insulin action in skeletal muscle cells. Endocrinology 2006; 147:3333-43. [PMID: 16574795 DOI: 10.1210/en.2005-0382] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Integrins mediate interactions between cells and extracellular matrix proteins that modulate growth factor signaling. Focal adhesion kinase (FAK) is a key multifunctional integrin pathway protein. We recently reported that disruption of FAK impairs insulin-mediated glycogen synthesis in hepatocytes. To test the hypothesis that FAK regulates skeletal muscle insulin action, we reduced FAK expression in L6 myotubes using FAK antisense. In untransfected myotubes, insulin stimulated both FAK tyrosine phosphorylation and kinase activity. Cells treated with antisense FAK showed 78 and 53% reductions in FAK mRNA and FAK protein, respectively, whereas insulin receptor substrate 1/2 and paxillin abundance were unaffected. Insulin-stimulated U-(14)C-glucose incorporation into glycogen was abolished by FAK antisense, and 2-deoxy-glucose uptake and glucose transporter 4 (GLUT4) translocation were both markedly attenuated. Antisense FAK did not alter GLUT1 or GLUT3 protein abundance. Immunofluorescence staining showed decreased FAK Tyr(397) phosphorylation and reduced actin stress fibers. Thus, in skeletal myotubes, FAK regulates the insulin-mediated cytoskeletal rearrangement essential for normal glucose transport and glycogen synthesis. Integrin signaling may play an important regulatory role in muscle insulin action.
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Affiliation(s)
- Danshan Huang
- Division of Endocrinology, Diabetes and Hypertension, Diabetes Center, David Geffen School of Medicine at University of California, Los Angeles, 90095, USA
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Ragolia L, Palaia T, Hall CE, Maesaka JK, Eguchi N, Urade Y. Accelerated glucose intolerance, nephropathy, and atherosclerosis in prostaglandin D2 synthase knock-out mice. J Biol Chem 2005; 280:29946-55. [PMID: 15970590 DOI: 10.1074/jbc.m502927200] [Citation(s) in RCA: 96] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Type 2 diabetics have an increased risk of developing atherosclerosis, suggesting the mechanisms that cause this disease are enhanced by insulin resistance. In this study we examined the effects of gene knock-out (KO) of lipocalin-type prostaglandin D(2) synthase (L-PGDS), a protein found at elevated levels in type 2 diabetics, on diet-induced glucose tolerance and atherosclerosis. Our results show that L-PGDS KO mice become glucose-in-tolerant and insulin-resistant at an accelerated rate when compared with the C57BL/6 control strain. Adipocytes were significantly larger in the L-PGDS KO mice compared with controls on the same diets. Cell culture data revealed significant differences between insulin-stimulated mitogen-activated protein kinase phosphatase-2, protein-tyrosine phosphatase-1D, and phosphorylated focal adhesion kinase expression levels in L-PGDS KO vascular smooth muscle cells and controls. In addition, only the L-PGDS KO mice developed nephropathy and an aortic thickening reminiscent to the early stages of atherosclerosis when fed a "diabetogenic" high fat diet. We conclude that L-PGDS plays an important role regulating insulin sensitivity and atherosclerosis in type 2 diabetes and may represent a novel model of insulin resistance, atherosclerosis, and diabetic nephropathy.
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Affiliation(s)
- Louis Ragolia
- Vascular Biology Laboratory, Winthrop-University Hospital, Mineola, New York 11501, USA.
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Meng TC, Buckley DA, Galic S, Tiganis T, Tonks NK. Regulation of insulin signaling through reversible oxidation of the protein-tyrosine phosphatases TC45 and PTP1B. J Biol Chem 2004; 279:37716-25. [PMID: 15192089 DOI: 10.1074/jbc.m404606200] [Citation(s) in RCA: 207] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Many studies have illustrated that the production of reactive oxygen species (ROS) is important for optimal tyrosine phosphorylation and signaling in response to diverse stimuli. Protein-tyrosine phosphatases (PTPs), which are important regulators of signal transduction, are exquisitely sensitive to inhibition after generation of ROS, and reversible oxidation is becoming recognized as a general physiological mechanism for regulation of PTP function. Thus, production of ROS facilitates a tyrosine phosphorylation-dependent cellular signaling response by transiently inactivating those PTPs that normally suppress the signal. In this study, we have explored the importance of reversible PTP oxidation in the signaling response to insulin. Using a modified ingel PTP assay, we show that stimulation of cells with insulin resulted in the rapid and transient oxidation and inhibition of two distinct PTPs, which we have identified as PTP1B and TC45, the 45-kDa spliced variant of the T cell protein-tyrosine phosphatase. We investigated further the role of TC45 as a regulator of insulin signaling by combining RNA interference and the use of substrate-trapping mutants. We have shown that TC45 is an inhibitor of insulin signaling, recognizing the beta-subunit of the insulin receptor as a substrate. The data also suggest that this strategy, using ligand-induced oxidation to tag specific PTPs and using interference RNA and substrate-trapping mutants to illustrate their role as regulators of particular signal transduction pathways, may be applied broadly across the PTP family to explore function.
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Affiliation(s)
- Tzu-Ching Meng
- Cold Spring Harbor Laboratory, Cold Spring Harbor, New York 11724, USA
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35
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Probst I, Beuers U, Drabent B, Unthan-Fechner K, Bütikofer P. The diacylglycerol and protein kinase C pathways are not involved in insulin signalling in primary rat hepatocytes. ACTA ACUST UNITED AC 2004; 270:4635-46. [PMID: 14622250 DOI: 10.1046/j.1432-1033.2003.03853.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Diacylglycerol (DAG) and protein kinase C (PKC) isoforms have been implicated in insulin signalling in muscle and fat cells. We evaluated the involvement of DAG and PKC in the action of insulin in adult rat hepatocytes cultured with dexamethasone, but in the absence of serum, for 48 h. Our results show that although insulin stimulated glycolysis and glycogen synthesis, it had no effect on DAG mass or molecular species composition. Epidermal growth factor showed the expected insulin-mimetic effect on glycolysis, whereas ATP and exogenous phospholipase C acted as antagonists and abolished the insulin signal. Similarly to insulin, epidermal growth factor had no effect on DAG mass or molecular species composition. In contrast, both ATP and phospholipase C induced a prominent increase in several DAG molecular species, including 18:0/20:4, 18:0/20:5, 18:0/22:5 and a decrease in 18:1/18:1. These changes were paralleled by an increase in phospholipase D activity, which was absent in insulin-treated cells. By immunoblotting or by measuring PKC activity, we found that neither insulin nor ATP translocated the PKCalpha, -delta, -epsilon or -zeta isoforms from the cytosol to the membrane in cells cultured for six or 48 h. Similarly, insulin had no effect on immunoprecipitable PKCzeta. Suppression of the glycogenic insulin signal by phorbol 12-myristate 13-acetate, but not by ATP, could be completely alleviated by bisindolylmaleimide. Finally, insulin showed no effect on DAG mass or translocation of PKC isoforms in the perfused liver, although it reduced the glucagon-stimulated glucose output by 75%. Together these results indicate that phospholipases C and D or multiple PKC isoforms are not involved in the hepatic insulin signal chain.
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Affiliation(s)
- Irmelin Probst
- Institut für Biochemie und Molekulare Zellbiologie, Georg-August - Universität Göttingen, Germany.
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36
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Gao Y, Walder K, Sunderland T, Kantham L, Feng HC, Quick M, Bishara N, de Silva A, Augert G, Tenne-Brown J, Collier GR. Elevation in Tanis expression alters glucose metabolism and insulin sensitivity in H4IIE cells. Diabetes 2003; 52:929-34. [PMID: 12663463 DOI: 10.2337/diabetes.52.4.929] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Increased hepatic glucose output and decreased glucose utilization are implicated in the development of type 2 diabetes. We previously reported that the expression of a novel gene, Tanis, was upregulated in the liver during fasting in the obese/diabetic animal model Psammomys obesus. Here, we have further studied the protein and its function. Cell fractionation indicated that Tanis was localized in the plasma membrane and microsomes but not in the nucleus, mitochondria, or soluble protein fraction. Consistent with previous gene expression data, hepatic Tanis protein levels increased more significantly in diabetic P. obesus than in nondiabetic controls after fasting. We used a recombinant adenovirus to increase Tanis expression in hepatoma H4IIE cells and investigated its role in metabolism. Tanis overexpression reduced glucose uptake, basal and insulin-stimulated glycogen synthesis, and glycogen content and attenuated the suppression of PEPCK gene expression by insulin, but it did not affect insulin-stimulated insulin receptor phosphorylation or triglyceride synthesis. These results suggest that Tanis may be involved in the regulation of glucose metabolism, and increased expression of Tanis could contribute to insulin resistance in the liver.
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Affiliation(s)
- Yuan Gao
- Metabolic Research Unit, School of Health Sciences, Deakin University, Victoria, Australia.
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