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Zheng Y, Song J, Qian Q, Wang H. Silver nanoparticles induce liver inflammation through ferroptosis in zebrafish. CHEMOSPHERE 2024; 362:142673. [PMID: 38945227 DOI: 10.1016/j.chemosphere.2024.142673] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/07/2024] [Revised: 06/11/2024] [Accepted: 06/19/2024] [Indexed: 07/02/2024]
Abstract
As the most widely employed artificial nanomaterials, silver nanoparticles (AgNPs) have been implicated in oxidative stress-induced liver injury. Despite these observations, the precise mechanisms underpinning AgNPs-induced hepatotoxicity have yet to be fully elucidated. This study embarked on an intersectional analysis of the GEO dataset (GSE139560), which encompassed murine liver tissues subjected to AgNPs, alongside datasets related to ferroptosis. Through this approach, three pivotal ferroptosis-associated genes (Arrdc3, Txnip, and Egfr) were identified. Further integration with disease model analysis from GSE111407 and GSE183158 unveiled a significant association between AgNPs exposure and alterations in glucose metabolism and insulin signaling pathways, intricately linked with the identified key ferroptosis genes. This correlation fostered the hypothesis that ferroptosis significantly contributed to the hepatotoxicity triggered by AgNPs. Subsequent Gene Set Enrichment Analysis (GSEA) pointed to the activation of ferroptosis-associated pathways, specifically MAPK and PPAR, under AgNPs exposure. Examination of the miRNA-mRNA interaction network revealed co-regulated upstream miRNAs targeting these pivotal genes, establishing a nexus to ferroptosis and heightened liver susceptibility. Experimental validation employing an adult zebrafish model exposed to AgNPs from 90 to 120 dpf demonstrated elevated levels of Fe2+ and MDA in the zebrafish livers, along with conspicuous mitochondrial morphological alterations, thereby reinforcing the notion that AgNPs precipitate liver dysfunction predominantly through the induction of ferroptosis. These insights collectively underscore the role of ferroptosis in mediating the adverse effects of AgNPs on liver glucose metabolism and insulin sensitivity, culminating in liver dysfunction. Overall, these results enhance the understanding of nanomaterial-induced hepatotoxicity and inform strategies to mitigate such health risks.
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Affiliation(s)
- Yuansi Zheng
- College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, 430074, China; Department of Pathology, Zhejiang Cancer Hospital, Hangzhou, Zhejiang, 310022, China
| | - Jie Song
- National and Local Joint Engineering Laboratory of Municipal Sewage Resource Utilization Technology, School of Environmental Science and Engineering, Suzhou University of Science and Technology, Suzhou, 215009, China
| | - Qiuhui Qian
- National and Local Joint Engineering Laboratory of Municipal Sewage Resource Utilization Technology, School of Environmental Science and Engineering, Suzhou University of Science and Technology, Suzhou, 215009, China.
| | - Huili Wang
- National and Local Joint Engineering Laboratory of Municipal Sewage Resource Utilization Technology, School of Environmental Science and Engineering, Suzhou University of Science and Technology, Suzhou, 215009, China.
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Zhang XL, Hollander CM, Khan MY, D'silva M, Ma H, Yang X, Bai R, Keeter CK, Galkina EV, Nadler JL, Stanton PK. Myeloid cell deficiency of the inflammatory transcription factor Stat4 protects long-term synaptic plasticity from the effects of a high-fat, high-cholesterol diet. Commun Biol 2023; 6:967. [PMID: 37783748 PMCID: PMC10545833 DOI: 10.1038/s42003-023-05304-0] [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: 07/04/2022] [Accepted: 08/30/2023] [Indexed: 10/04/2023] Open
Abstract
Neuroinflammation is associated with neurodegenerative diseases, including Alzheimer's and Parkinson's. The cytokine interleukin-12 activates signal transducer and activator of transcription 4 (Stat4), and consumption of a high-fat, high-cholesterol diet (HFD-C) and Stat4 activity are associated with inflammation, atherosclerosis, and a diabetic metabolic phenotype. In studies of in vitro hippocampal slices from control Stat4fl/flLdlr-/- mice fed a HFD-C diabetogenic diet, we show that Schaffer collateral-CA1 synapses exhibited larger reductions in activity-dependent, long-term potentiation (LTP) of synaptic transmission, compared to mice fed a standard diet. Glucose tolerance and insulin sensitivity shifts produced by HFD-C diet were reduced in Stat4ΔLysMLdlr-/- mice compared to Stat4fl/flLdlr-/- controls. Stat4ΔLysMLdlr-/- mice, which lack Stat4 under control of the LysMCre promoter, were resistant to HFD-C induced impairments in LTP. In contrast, Schaffer collateral-CA1 synapses in Stat4ΔLysMLdlr-/- mice fed the HFD-C diet showed larger LTP than control Stat4fl/flLdlr-/- mice. Expression of a number of neuroinflammatory and synaptic plasticity genes was reduced by HFD-C diet in control mice, and less affected by HFD-C diet in Stat4ΔLysMLdlr-/- mice. These data suggest that suppression of Stat4 activation may protect against effects of Western diet on cognition, type 2 diabetes, and reduce risk of Alzheimer's disease and other neurodegenerative disorders associated with neuroinflammation.
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Affiliation(s)
- Xiao-Lei Zhang
- Department of Cell Biology & Anatomy, New York Medical College, Valhalla, NY, 10595, USA
| | - Callie M Hollander
- Department of Cell Biology & Anatomy, New York Medical College, Valhalla, NY, 10595, USA
| | - Mohammad Yasir Khan
- Department of Pharmacology, New York Medical College, Valhalla, NY, 10595, USA
| | - Melinee D'silva
- Department of Pharmacology, New York Medical College, Valhalla, NY, 10595, USA
| | - Haoqin Ma
- Department of Cell Biology & Anatomy, New York Medical College, Valhalla, NY, 10595, USA
| | - Xinyuan Yang
- Department of Cell Biology & Anatomy, New York Medical College, Valhalla, NY, 10595, USA
| | - Robin Bai
- Department of Microbiology & Molecular Cell Biology, Eastern Virginia Medical School, Norfolk, VA, 23507, USA
| | - Coles K Keeter
- Department of Microbiology & Molecular Cell Biology, Eastern Virginia Medical School, Norfolk, VA, 23507, USA
| | - Elena V Galkina
- Department of Microbiology & Molecular Cell Biology, Eastern Virginia Medical School, Norfolk, VA, 23507, USA
- Center for Integrative Neuroscience and Inflammatory Diseases, Eastern Virginia Medical School, Norfolk, VA, 23507, USA
| | - Jerry L Nadler
- Department of Pharmacology, New York Medical College, Valhalla, NY, 10595, USA
- ACOS-Research VA Northern California Health Care System, Sacramento, CA, 95655, USA
| | - Patric K Stanton
- Department of Cell Biology & Anatomy, New York Medical College, Valhalla, NY, 10595, USA.
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Dagdeviren S, Hoang MF, Sarikhani M, Meier V, Benoit JC, Okawa MC, Melnik VY, Ricci-Blair EM, Foot N, Friedline RH, Hu X, Tauer LA, Srinivasan A, Prigozhin MB, Shenoy SK, Kumar S, Kim JK, Lee RT. An insulin-regulated arrestin domain protein controls hepatic glucagon action. J Biol Chem 2023; 299:105045. [PMID: 37451484 PMCID: PMC10413355 DOI: 10.1016/j.jbc.2023.105045] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2022] [Revised: 06/16/2023] [Accepted: 07/07/2023] [Indexed: 07/18/2023] Open
Abstract
Glucagon signaling is essential for maintaining normoglycemia in mammals. The arrestin fold superfamily of proteins controls the trafficking, turnover, and signaling of transmembrane receptors as well as other intracellular signaling functions. Further investigation is needed to understand the in vivo functions of the arrestin domain-containing 4 (ARRDC4) protein family member and whether it is involved in mammalian glucose metabolism. Here, we show that mice with a global deletion of the ARRDC4 protein have impaired glucagon responses and gluconeogenesis at a systemic and molecular level. Mice lacking ARRDC4 exhibited lower glucose levels after fasting and could not suppress gluconeogenesis at the refed state. We also show that ARRDC4 coimmunoprecipitates with the glucagon receptor, and ARRDC4 expression is suppressed by insulin. These results define ARRDC4 as a critical regulator of glucagon signaling and glucose homeostasis and reveal a novel intersection of insulin and glucagon pathways in the liver.
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Affiliation(s)
- Sezin Dagdeviren
- Department of Stem Cell and Regenerative Biology and the Harvard Stem Cell Institute, Harvard University, Cambridge, Massachusetts, USA
| | - Megan F Hoang
- Department of Stem Cell and Regenerative Biology and the Harvard Stem Cell Institute, Harvard University, Cambridge, Massachusetts, USA
| | - Mohsen Sarikhani
- Department of Stem Cell and Regenerative Biology and the Harvard Stem Cell Institute, Harvard University, Cambridge, Massachusetts, USA
| | - Vanessa Meier
- Department of Stem Cell and Regenerative Biology and the Harvard Stem Cell Institute, Harvard University, Cambridge, Massachusetts, USA
| | - Jake C Benoit
- Department of Stem Cell and Regenerative Biology and the Harvard Stem Cell Institute, Harvard University, Cambridge, Massachusetts, USA
| | - Marinna C Okawa
- Department of Stem Cell and Regenerative Biology and the Harvard Stem Cell Institute, Harvard University, Cambridge, Massachusetts, USA
| | - Veronika Y Melnik
- Department of Stem Cell and Regenerative Biology and the Harvard Stem Cell Institute, Harvard University, Cambridge, Massachusetts, USA
| | - Elisabeth M Ricci-Blair
- Department of Stem Cell and Regenerative Biology and the Harvard Stem Cell Institute, Harvard University, Cambridge, Massachusetts, USA
| | - Natalie Foot
- Centre for Cancer Biology, University of South Australia, Adelaide, Australia
| | - Randall H Friedline
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, Massachusetts, USA
| | - Xiaodi Hu
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, Massachusetts, USA
| | - Lauren A Tauer
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, Massachusetts, USA
| | - Arvind Srinivasan
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, Massachusetts, USA
| | - Maxim B Prigozhin
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, Massachusetts, USA; John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts, USA
| | - Sudha K Shenoy
- Division of Cardiology, Department of Medicine, Duke University Medical Center, Durham, North Carolina, USA; Department of Cell Biology, Duke University Medical Center, Durham, North Carolina, USA
| | - Sharad Kumar
- Centre for Cancer Biology, University of South Australia, Adelaide, Australia
| | - Jason K Kim
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, Massachusetts, USA; Department of Medicine, Division of Endocrinology, Metabolism, and Diabetes, University of Massachusetts Medical School, Worcester, Massachusetts, USA.
| | - Richard T Lee
- Department of Stem Cell and Regenerative Biology and the Harvard Stem Cell Institute, Harvard University, Cambridge, Massachusetts, USA.
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Avequin T, Lau KH, Waldhart AN, Guak H, Dykstra H, Krawczyk C, Wu N. Differential effects of sugar and fat on adipose tissue inflammation. iScience 2023; 26:107163. [PMID: 37456843 PMCID: PMC10338233 DOI: 10.1016/j.isci.2023.107163] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2022] [Revised: 12/05/2022] [Accepted: 06/13/2023] [Indexed: 07/18/2023] Open
Abstract
Obese individuals experience low grade inflammation initiated within their adipose tissue. However, the early events that lead to the release of these inflammatory factors from adipose tissue are poorly characterized. To separate glucose effects from lipid effects on adipose tissue, we used an adipose-specific TXNIP knockout model where excess basal glucose influx into adipocytes led to modest increase in adiposity without using high fat diet. We found an uncoupling of two events that are generally presumed to be coregulated: (1) an increase of adipose tissue macrophage (ATM) number; and (2) pro-inflammatory activation of ATMs. These two events are associated with different triggering signals: elevated free fatty acids output and extracellular matrix remodeling with increased ATM number, whereas decreased adiponectin level with activated ATM. This separation reflects non-overlapping pathways regulated by glucose and lipids in adipocytes, and neither group alone is sufficient to elicit the full inflammatory response in adipose tissue.
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Affiliation(s)
| | - Kin H. Lau
- Van Andel Institute, Grand Rapids, MI 49503, USA
| | | | - Hannah Guak
- Department of Pediatrics, University of Michigan, Ann Arbor, MI 48109, USA
| | | | | | - Ning Wu
- Van Andel Institute, Grand Rapids, MI 49503, USA
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Keller MP, Hudkins KL, Shalev A, Bhatnagar S, Kebede MA, Merrins MJ, Davis DB, Alpers CE, Kimple ME, Attie AD. What the BTBR/J mouse has taught us about diabetes and diabetic complications. iScience 2023; 26:107036. [PMID: 37360692 PMCID: PMC10285641 DOI: 10.1016/j.isci.2023.107036] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/28/2023] Open
Abstract
Human and mouse genetics have delivered numerous diabetogenic loci, but it is mainly through the use of animal models that the pathophysiological basis for their contribution to diabetes has been investigated. More than 20 years ago, we serendipidously identified a mouse strain that could serve as a model of obesity-prone type 2 diabetes, the BTBR (Black and Tan Brachyury) mouse (BTBR T+ Itpr3tf/J, 2018) carrying the Lepob mutation. We went on to discover that the BTBR-Lepob mouse is an excellent model of diabetic nephropathy and is now widely used by nephrologists in academia and the pharmaceutical industry. In this review, we describe the motivation for developing this animal model, the many genes identified and the insights about diabetes and diabetes complications derived from >100 studies conducted in this remarkable animal model.
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Affiliation(s)
- Mark P. Keller
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Kelly L. Hudkins
- Department of Pathology, University of Washington Medical Center, Seattle, WA 98195, USA
| | - Anath Shalev
- Department of Medicine, Division of Endocrinology, Diabetes, and Metabolism, University of Alabama at Birmingham, Birmingham, AL 35294, UK
| | - Sushant Bhatnagar
- Department of Medicine, Division of Endocrinology, Diabetes, and Metabolism, University of Alabama at Birmingham, Birmingham, AL 35294, UK
| | - Melkam A. Kebede
- School of Medical Sciences, Faculty of Medicine and Health, Charles Perkins Centre, University of Sydney, Camperdown, Sydney, NSW 2006, Australia
| | - Matthew J. Merrins
- Department of Medicine, Division of Endocrinology, Diabetes, and Metabolism, University of Wisconsin School of Medicine and Public Health, Madison, WI 53705, USA
- William S. Middleton Memorial Veterans Hospital, Madison, WI 53705, USA
| | - Dawn Belt Davis
- Department of Medicine, Division of Endocrinology, Diabetes, and Metabolism, University of Wisconsin School of Medicine and Public Health, Madison, WI 53705, USA
- William S. Middleton Memorial Veterans Hospital, Madison, WI 53705, USA
| | - Charles E. Alpers
- Department of Pathology, University of Washington Medical Center, Seattle, WA 98195, USA
| | - Michelle E. Kimple
- Department of Medicine, Division of Endocrinology, Diabetes, and Metabolism, University of Wisconsin School of Medicine and Public Health, Madison, WI 53705, USA
- William S. Middleton Memorial Veterans Hospital, Madison, WI 53705, USA
| | - Alan D. Attie
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706, USA
- Department of Medicine, Division of Endocrinology, Diabetes, and Metabolism, University of Wisconsin School of Medicine and Public Health, Madison, WI 53705, USA
- Department of Chemistry, University of Wisconsin-Madison, Madison, WI 53706, USA
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Guo Q, Xin M, Lu Q, Feng D, Yang V, Peng LF, Whelan KA, Hu W, Wu S, Yang X, Wang H, Rothberg BS, Gamero AM, Gerhard GS, Gao B, Yang L. A novel NEDD4L-TXNIP-CHOP axis in the pathogenesis of nonalcoholic steatohepatitis. Theranostics 2023; 13:2210-2225. [PMID: 37153733 PMCID: PMC10157740 DOI: 10.7150/thno.81192] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2022] [Accepted: 04/04/2023] [Indexed: 05/10/2023] Open
Abstract
Background: Nonalcoholic steatohepatitis (NASH) is a leading cause of chronic liver diseases worldwide. There is a pressing clinical need to identify potential therapeutic targets for NASH treatment. Thioredoxin interacting protein (Txnip) is a stress responsive gene that has been implicated in the pathogenesis of NASH, but its exact role is not fully understood. Here, we investigated the liver- and gene-specific role of Txnip and its upstream/downstream signaling in the pathogenesis of NASH. Methods and Results: Using four independent NASH mouse models, we found that TXNIP protein abnormally accumulated in NASH mouse livers. A decrease in E3 ubiquitin ligase NEDD4L resulted in impaired TXNIP ubiquitination and its accumulation in the liver. TXNIP protein levels were positively correlated with that of CHOP, a major regulator of ER stress-mediated apoptosis, in NASH mouse liver. Moreover, gain- and loss-of-function studies showed that TXNIP increased protein not mRNA levels of Chop both in vitro and in vivo. Mechanistically, the C-terminus of TXNIP associated with the N-terminus of the α-helix domain of CHOP and decreased CHOP ubiquitination, thus increasing the stability of CHOP protein. Lastly, selective knockdown of Txnip by adenovirus-mediated shRNA (not targets Txnip antisense lncRNA) delivery in the livers of both young and aged NASH mice suppressed the expression of CHOP and its downstream apoptotic pathway, and ameliorated NASH by reducing hepatic apoptosis, inflammation, and fibrosis. Conclusions: Our study revealed a pathogenic role of hepatic TXNIP in NASH and identified a novel NEDD4L-TXNIP-CHOP axis in the pathogenesis of NASH.
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Affiliation(s)
- Qian Guo
- Department of Medical Genetics and Molecular Biochemistry, Lewis Katz School of Medicine at Temple University, Philadelphia, Pennsylvania, USA
| | - Mingyang Xin
- Department of Medical Genetics and Molecular Biochemistry, Lewis Katz School of Medicine at Temple University, Philadelphia, Pennsylvania, USA
| | - Qingchun Lu
- Department of Medical Genetics and Molecular Biochemistry, Lewis Katz School of Medicine at Temple University, Philadelphia, Pennsylvania, USA
| | - Dechun Feng
- Laboratory of Liver Diseases, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, Maryland, USA
| | - Vicky Yang
- Department of Medical Genetics and Molecular Biochemistry, Lewis Katz School of Medicine at Temple University, Philadelphia, Pennsylvania, USA
| | - Lee F. Peng
- Division of Hepatology, Lewis Katz School of Medicine at Temple University, Philadelphia, Pennsylvania, USA
| | - Kelly A. Whelan
- Department of Cancer and Cellular Biology, Lewis Katz School of Medicine at Temple University, Philadelphia, Pennsylvania, USA
| | - Wenhui Hu
- Department of Cardiovascular Sciences/Center for Metabolic Disease Research, Lewis Katz School of Medicine at Temple University, Philadelphia, Pennsylvania, USA
| | - Sheng Wu
- Department of Cardiovascular Sciences/Center for Metabolic Disease Research, Lewis Katz School of Medicine at Temple University, Philadelphia, Pennsylvania, USA
| | - Xiaofeng Yang
- Department of Cardiovascular Sciences/Center for Metabolic Disease Research, Lewis Katz School of Medicine at Temple University, Philadelphia, Pennsylvania, USA
| | - Hong Wang
- Department of Cardiovascular Sciences/Center for Metabolic Disease Research, Lewis Katz School of Medicine at Temple University, Philadelphia, Pennsylvania, USA
| | - Brad S. Rothberg
- Department of Medical Genetics and Molecular Biochemistry, Lewis Katz School of Medicine at Temple University, Philadelphia, Pennsylvania, USA
| | - Ana M. Gamero
- Department of Medical Genetics and Molecular Biochemistry, Lewis Katz School of Medicine at Temple University, Philadelphia, Pennsylvania, USA
| | - Glenn S. Gerhard
- Department of Medical Genetics and Molecular Biochemistry, Lewis Katz School of Medicine at Temple University, Philadelphia, Pennsylvania, USA
| | - Bin Gao
- Laboratory of Liver Diseases, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, Maryland, USA
| | - Ling Yang
- Department of Medical Genetics and Molecular Biochemistry, Lewis Katz School of Medicine at Temple University, Philadelphia, Pennsylvania, USA
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Zhou D, Li X, Xiao X, Wang G, Chen B, Song Y, Liu X, He Q, Zhang H, Wu Q, Zhang L, Wu L, Shen Z, Hassan M, Zhao Y, Zhou W. Celastrol targets the ChREBP-TXNIP axis to ameliorates type 2 diabetes mellitus. PHYTOMEDICINE : INTERNATIONAL JOURNAL OF PHYTOTHERAPY AND PHYTOPHARMACOLOGY 2023; 110:154634. [PMID: 36603341 DOI: 10.1016/j.phymed.2022.154634] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/12/2022] [Revised: 11/29/2022] [Accepted: 12/26/2022] [Indexed: 06/17/2023]
Abstract
BACKGROUNDS Thioredoxin-interacting protein (TXNIP) plays a pivotal role in regulation of blood glucose homeostasis and is an emerging therapeutic target in diabetes and its complications. Celastrol, a pentacyclic triterpene extracted from the roots of Tripterygium wilfordii Hook F, can reduce insulin resistance and improve diabetic complications. PURPOSE This study aimed to untangle the mechanism of celastrol in ameliorating type 2 diabetes (T2DM) and evaluate its potential benefits as an anti-diabetic agent. METHODS db/db mice was used to evaluate the hypoglycemic effect of celastrol in vivo; Enzyme-linked immunosorbent assay (ELISA) and 2-NBDG assay were used to detect the effect of celastrol on insulin secretion and glucose uptake in cells; Western blotting, quantitative reverse transcription PCR (RT-qPCR) and immunohistological staining were used to examine effect of celastrol on the expression of TXNIP and the carbohydrate response element-binding protein (ChREBP). Molecular docking, cellular thermal shift assay (CETSA), drug affinity responsive targets stability assay (DARTS) and mass spectrometry were used to test the direct binding between celastrol and ChREBP. Loss- and gain-of-function studies further confirmed the role of ChREBP and TXNIP in celastrol-mediated amelioration of T2DM. RESULTS Celastrol treatment significantly reduced blood glucose level, body weight and food intake, and improved glucose tolerance in db/db mice. Moreover, celastrol promoted insulin secretion and improved glucose homeostasis. Mechanistically, celastrol directly bound to ChREBP, a primary transcriptional factor upregulating TXNIP expression. By binding to ChREBP, celastrol inhibited its nuclear translocation and promoted its proteasomal degradation, thereby repressing TXNIP transcription and ultimately ameliorating T2DM through breaking the vicious cycle of hyperglycemia deterioration and TXNIP overexpression. CONCLUSION Celastrol ameliorates T2DM through targeting ChREBP-TXNIP aix. Our study identified ChREBP as a new direct molecular target of celastrol and revealed a novel mechanism for celastrol-mediated amelioration of T2DM, which provides experimental evidence for its possible use in the treatment of T2DM and new insight into diabetes drug development for targeting TXNIP.
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Affiliation(s)
- Duanfang Zhou
- Department of Pharmacology, College of Pharmacy, Chongqing Medical University, Chongqing, China; Chongqing Key Laboratory of Drug Metabolism, Chongqing, China; Department of pharmacy, Women and Children's Hospital of Chongqing Medical University, Chongqing, China
| | - Xiaoli Li
- Department of Pharmacology, College of Pharmacy, Chongqing Medical University, Chongqing, China; Chongqing Key Laboratory of Drug Metabolism, Chongqing, China; Key laboratory for Biochemistry and Molecular Pharmacology of Chongqing, Chongqing, China
| | - Xiaoqiu Xiao
- The Chongqing Key Laboratory of Translational Medicine in Major Metabolic Diseases, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Gang Wang
- Department of Pharmacology, College of Pharmacy, Chongqing Medical University, Chongqing, China; Chongqing Key Laboratory of Drug Metabolism, Chongqing, China
| | - Bo Chen
- Department of Pharmacology, College of Pharmacy, Chongqing Medical University, Chongqing, China; Chongqing Key Laboratory of Drug Metabolism, Chongqing, China
| | - Yi Song
- Department of Pharmacology, College of Pharmacy, Chongqing Medical University, Chongqing, China; Chongqing Key Laboratory of Drug Metabolism, Chongqing, China
| | - Xu Liu
- Department of Pharmacology, College of Pharmacy, Chongqing Medical University, Chongqing, China; Chongqing Key Laboratory of Drug Metabolism, Chongqing, China
| | - Qichen He
- Department of Pharmacology, College of Pharmacy, Chongqing Medical University, Chongqing, China; Chongqing Key Laboratory of Drug Metabolism, Chongqing, China
| | - Huan Zhang
- Department of Pharmacology, College of Pharmacy, Chongqing Medical University, Chongqing, China; Chongqing Key Laboratory of Drug Metabolism, Chongqing, China
| | - Qiuya Wu
- Department of Pharmacology, College of Pharmacy, Chongqing Medical University, Chongqing, China; Chongqing Key Laboratory of Drug Metabolism, Chongqing, China
| | - Limei Zhang
- Department of Pharmacology, College of Pharmacy, Chongqing Medical University, Chongqing, China; Chongqing Key Laboratory of Drug Metabolism, Chongqing, China
| | - Lihong Wu
- Department of Pharmacology, College of Pharmacy, Chongqing Medical University, Chongqing, China; Chongqing Key Laboratory of Drug Metabolism, Chongqing, China
| | - Zhengze Shen
- Department of pharmacy, Yongchuan Hospital of Chongqing Medical University, Chongqing, China
| | - Moustapha Hassan
- Experimental Cancer Medicine, Division of Bio-molecular and Cellular Medicine (BCM), Department of Laboratory Medicine, Karolinska Institutet, Sweden
| | - Ying Zhao
- Experimental Cancer Medicine, Division of Bio-molecular and Cellular Medicine (BCM), Department of Laboratory Medicine, Karolinska Institutet, Sweden
| | - Weiying Zhou
- Department of Pharmacology, College of Pharmacy, Chongqing Medical University, Chongqing, China; Chongqing Key Laboratory of Drug Metabolism, Chongqing, China; Key laboratory for Biochemistry and Molecular Pharmacology of Chongqing, Chongqing, China.
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Pathogenesis, Murine Models, and Clinical Implications of Metabolically Healthy Obesity. Int J Mol Sci 2022; 23:ijms23179614. [PMID: 36077011 PMCID: PMC9455655 DOI: 10.3390/ijms23179614] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2022] [Revised: 08/21/2022] [Accepted: 08/23/2022] [Indexed: 11/16/2022] Open
Abstract
Although obesity is commonly associated with numerous cardiometabolic pathologies, some people with obesity are resistant to detrimental effects of excess body fat, which constitutes a condition called “metabolically healthy obesity” (MHO). Metabolic features of MHO that distinguish it from metabolically unhealthy obesity (MUO) include differences in the fat distribution, adipokine types, and levels of chronic inflammation. Murine models are available that mimic the phenotype of human MHO, with increased adiposity but preserved insulin sensitivity. Clinically, there is no established definition of MHO yet. Despite the lack of a uniform definition, most studies describe MHO as a particular case of obesity with no or only one metabolic syndrome components and lower levels of insulin resistance or inflammatory markers. Another clinical viewpoint is the dynamic and changing nature of MHO, which substantially impacts the clinical outcome. In this review, we explore the pathophysiology and some murine models of MHO. The definition, variability, and clinical implications of the MHO phenotype are also discussed. Understanding the characteristics that differentiate people with MHO from those with MUO can lead to new insights into the mechanisms behind obesity-related metabolic derangements and diseases.
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Endothelial thioredoxin interacting protein (TXNIP) modulates endothelium-dependent vasorelaxation in hyperglycemia. Microvasc Res 2022; 143:104396. [PMID: 35644243 DOI: 10.1016/j.mvr.2022.104396] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2021] [Revised: 05/23/2022] [Accepted: 05/24/2022] [Indexed: 11/24/2022]
Abstract
Endothelial dysfunction, hallmarked by an imbalance between vasoconstriction and vasorelaxation, is associated with diabetes. Thioredoxin Interacting protein (TXNIP), controlled by an exquisitely glucose sensitive gene, is increasingly recognized for its role in diabetes. However, the role of TXNIP in modulating diabetes-related endothelial dysfunction remains unclear. To elucidate the role of TXNIP, we generated two novel mouse strains; endothelial-specific TXNIP knockout (EKO) and a Tet-O inducible, endothelial-specific TXNIP overexpression (EKI). Hyperglycemia was induced by streptozotocin (STZ) treatment in floxed control (fl/fl) and EKO mice. Doxycycline (DOX) was given to EKI mice to induce endothelial TXNIP overexpression. The ablation of endothelial TXNIP improved glucose tolerance in EKO mice. Acetylcholine-induced, endothelium-dependent vasorelaxation was impaired in STZ-treated fl/fl mice while this STZ impaired vasorelaxation was attenuated in EKO mice. Hyperglycemia induction of NLRP3 and reductions in Akt and eNOS phosphorylation were also mitigated in EKO mice. Overexpression of endothelial TXNIP did not impair glucose tolerance in DOX-treated EKI mice, however induction of endothelial TXNIP led to impaired vasorelaxation in EKI mice. This was associated with increased NLRP3 and reduced Akt and eNOS activation. In conclusion, deletion of endothelial TXNIP is protective against and overexpression of endothelial TXNIP induces endothelial dysfunction; thus, endothelial TXNIP plays a critical role in modulating endothelial dysfunction.
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Abstract
Significance: Thioredoxin-interacting protein (Txnip) is an α-arrestin protein that acts as a cancer suppressor. Txnip is simultaneously a critical regulator of energy metabolism. Other alpha-arrestin proteins also play key roles in cell biology and cancer. Recent Advances: Txnip expression is regulated by multilayered mechanisms, including transcriptional regulation, microRNA, messenger RNA (mRNA) stabilization, and protein degradation. The Txnip-based connection between cancer and metabolism has been widely recognized. Meanwhile, new aspects are proposed for the mechanism of action of Txnip, including the regulation of RNA expression and autophagy. Arrestin domain containing 3 (ARRDC3), another α-arrestin protein, regulates endocytosis and signaling, whereas ARRDC1 and ARRDC4 regulate extracellular vesicle formation. Critical Issues: The mechanism of action of Txnip is yet to be elucidated. The regulation of intracellular protein trafficking by arrestin family proteins has opened an emerging field of biology and medical research, which needs to be examined further. Future Directions: A fundamental understanding of the mechanism of action of Txnip and other arrestin family members needs to be explored in the future to combat diseases such as cancer and diabetes. Antioxid. Redox Signal. 36, 1001-1022.
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Affiliation(s)
- Hiroshi Masutani
- Department of Clinical Laboratory Sciences, Tenri Health Care University, Tenri, Japan.,Department of Infection and Prevention, Institute for Frontier Life and Medical Sciences, Kyoto University, Kyoto, Japan
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11
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α-Arrestins and Their Functions: From Yeast to Human Health. Int J Mol Sci 2022; 23:ijms23094988. [PMID: 35563378 PMCID: PMC9105457 DOI: 10.3390/ijms23094988] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Revised: 04/26/2022] [Accepted: 04/27/2022] [Indexed: 12/10/2022] Open
Abstract
α-Arrestins, also called arrestin-related trafficking adaptors (ARTs), constitute a large family of proteins conserved from yeast to humans. Despite their evolutionary precedence over their extensively studied relatives of the β-arrestin family, α-arrestins have been discovered relatively recently, and thus their properties are mostly unexplored. The predominant function of α-arrestins is the selective identification of membrane proteins for ubiquitination and degradation, which is an important element in maintaining membrane protein homeostasis as well as global cellular metabolisms. Among members of the arrestin clan, only α-arrestins possess PY motifs that allow canonical binding to WW domains of Rsp5/NEDD4 ubiquitin ligases and the subsequent ubiquitination of membrane proteins leading to their vacuolar/lysosomal degradation. The molecular mechanisms of the selective substrate’s targeting, function, and regulation of α-arrestins in response to different stimuli remain incompletely understood. Several functions of α-arrestins in animal models have been recently characterized, including redox homeostasis regulation, innate immune response regulation, and tumor suppression. However, the molecular mechanisms of α-arrestin regulation and substrate interactions are mainly based on observations from the yeast Saccharomyces cerevisiae model. Nonetheless, α-arrestins have been implicated in health disorders such as diabetes, cardiovascular diseases, neurodegenerative disorders, and tumor progression, placing them in the group of potential therapeutic targets.
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12
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Lei Z, Chen Y, Wang J, Zhang Y, Shi W, Wang X, Xing D, Li D, Jiao X. Txnip deficiency promotes β-cell proliferation in the HFD-induced obesity mouse model. Endocr Connect 2022; 11:EC-21-0641. [PMID: 35294398 PMCID: PMC9066588 DOI: 10.1530/ec-21-0641] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/10/2022] [Accepted: 03/16/2022] [Indexed: 11/25/2022]
Abstract
Elucidating the mechanisms of regulation of β-cell proliferation is key to understanding the pathogenesis of diabetes mellitus. Txnip is a tumor suppressor that is upregulated in diabetes and plays an important role in the regulation of insulin sensitivity; however, its potential effect on pancreatic β-cell proliferation remains unclear. Here, we evaluated the role of Txnip in pancreatic β-cell compensatory proliferation by subjecting WT and Txnip knockout (KO) mice to a high-fat diet (HFD). Our results demonstrate that Txnip deficiency improves glucose tolerance and increases insulin sensitivity in HFD-induced obesity. The antidiabetogenic effect of Txnip deficiency was accompanied by increased β-cell proliferation and enhanced β-cell mass expansion. Furthermore, Txnip deficiency modulated the expression of a set of transcription factors with key roles in β-cell proliferation and cell cycle regulation. Txnip KO in HFD mice also led to activated levels of p-PI3K, p-AKT, p-mTOR and p-GSK3β, suggesting that Txnip may act via PI3K/AKT signaling to suppress β-cell proliferation. Thus, our work provides a theoretical basis for Txnip as a new therapeutic target for the treatment of diabetes mellitus.
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Affiliation(s)
- Zhandong Lei
- Key Laboratory of Cellular Physiology, Ministry of Education, and the Department of Physiology, Shanxi Medical University, Taiyuan, China
- Department of Anatomy, Shanxi Medical University, Taiyuan, China
| | - Yunfei Chen
- Key Laboratory of Cellular Physiology, Ministry of Education, and the Department of Physiology, Shanxi Medical University, Taiyuan, China
| | - Jin Wang
- Key Laboratory of Cellular Physiology, Ministry of Education, and the Department of Physiology, Shanxi Medical University, Taiyuan, China
| | - Yan Zhang
- Key Laboratory of Cellular Physiology, Ministry of Education, and the Department of Physiology, Shanxi Medical University, Taiyuan, China
| | - Wenjuan Shi
- Key Laboratory of Cellular Physiology, Ministry of Education, and the Department of Physiology, Shanxi Medical University, Taiyuan, China
| | - Xuejiao Wang
- Key Laboratory of Cellular Physiology, Ministry of Education, and the Department of Physiology, Shanxi Medical University, Taiyuan, China
| | - Dehai Xing
- Key Laboratory of Cellular Physiology, Ministry of Education, and the Department of Physiology, Shanxi Medical University, Taiyuan, China
| | - Dongxue Li
- Key Laboratory of Cellular Physiology, Ministry of Education, and the Department of Physiology, Shanxi Medical University, Taiyuan, China
| | - Xiangying Jiao
- Key Laboratory of Cellular Physiology, Ministry of Education, and the Department of Physiology, Shanxi Medical University, Taiyuan, China
- Correspondence should be addressed to X Jiao:
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13
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Zarkasi KA, Abdul Murad NA, Ahmad N, Jamal R, Abdullah N. Coronary Heart Disease in Type 2 Diabetes Mellitus: Genetic Factors and Their Mechanisms, Gene-Gene, and Gene-Environment Interactions in the Asian Populations. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2022; 19:647. [PMID: 35055468 PMCID: PMC8775550 DOI: 10.3390/ijerph19020647] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/07/2021] [Revised: 01/03/2022] [Accepted: 01/04/2022] [Indexed: 02/04/2023]
Abstract
Asians are more susceptible to type 2 diabetes mellitus (T2D) and its coronary heart disease (CHD) complications than the Western populations, possibly due to genetic factors, higher degrees of obesity, insulin resistance, and endothelial dysfunction that could occur even in healthy individuals. The genetic factors and their mechanisms, along with gene-gene and gene-environment interactions associated with CHD in T2D Asians, are yet to be explored. Therefore, the objectives of this paper were to review the current evidence of genetic factors for CHD, summarize the proposed mechanisms of these genes and how they may associate with CHD risk, and review the gene-gene and gene-environment interactions in T2D Asians with CHD. The genetic factors can be grouped according to their involvement in the energy and lipoprotein metabolism, vascular and endothelial pathology, antioxidation, cell cycle regulation, DNA damage repair, hormonal regulation of glucose metabolism, as well as cytoskeletal function and intracellular transport. Meanwhile, interactions between single nucleotide polymorphisms (SNPs) from different genes, SNPs within a single gene, and genetic interaction with environmental factors including obesity, smoking habit, and hyperlipidemia could modify the gene's effect on the disease risk. Collectively, these factors illustrate the complexities of CHD in T2D, specifically among Asians.
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Affiliation(s)
- Khairul Anwar Zarkasi
- UKM Medical Molecular Biology Institute (UMBI), Universiti Kebangsaan Malaysia (UKM), Kuala Lumpur 56000, Malaysia; (K.A.Z.); (N.A.A.M.); (R.J.)
- Biochemistry Unit, Preclinical Department, Faculty of Medicine and Defence Health, Universiti Pertahanan Nasional Malaysia, Kuala Lumpur 57000, Malaysia
| | - Nor Azian Abdul Murad
- UKM Medical Molecular Biology Institute (UMBI), Universiti Kebangsaan Malaysia (UKM), Kuala Lumpur 56000, Malaysia; (K.A.Z.); (N.A.A.M.); (R.J.)
| | - Norfazilah Ahmad
- Epidemiology and Statistics Unit, Department of Community Health, Faculty of Medicine, Universiti Kebangsaan Malaysia (UKM), Kuala Lumpur 56000, Malaysia;
| | - Rahman Jamal
- UKM Medical Molecular Biology Institute (UMBI), Universiti Kebangsaan Malaysia (UKM), Kuala Lumpur 56000, Malaysia; (K.A.Z.); (N.A.A.M.); (R.J.)
| | - Noraidatulakma Abdullah
- UKM Medical Molecular Biology Institute (UMBI), Universiti Kebangsaan Malaysia (UKM), Kuala Lumpur 56000, Malaysia; (K.A.Z.); (N.A.A.M.); (R.J.)
- Faculty of Health Sciences, Universiti Kebangsaan Malaysia (UKM), Kuala Lumpur 50300, Malaysia
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14
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Yu W, Chen C, Zhuang W, Wang W, Liu W, Zhao H, Lv J, Xie D, Wang Q, He F, Xu C, Chen B, Yamamoto T, Koyama H, Cheng J. Silencing TXNIP ameliorates high uric acid-induced insulin resistance via the IRS2/AKT and Nrf2/HO-1 pathways in macrophages. Free Radic Biol Med 2022; 178:42-53. [PMID: 34848368 DOI: 10.1016/j.freeradbiomed.2021.11.034] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Revised: 11/22/2021] [Accepted: 11/24/2021] [Indexed: 02/08/2023]
Abstract
Insulin resistance (IR) promotes atherosclerosis and increases the risk of diabetes and cardiovascular diseases. Our previous studies have demonstrated that high uric acid (HUA) increased oxidative stress, leading to IR in cardiomyocytes and pancreatic β cells. However, whether HUA can induce IR in monocytes/macrophages, which play critical roles in all stages of atherosclerosis, is unclear. Recent findings revealed that thioredoxin-interacting protein (TXNIP) negatively regulates insulin signaling; however, the roles and mechanisms of TXNIP in HUA-induced IR remain unclear. Therefore, in this study, we investigated the function of TXNIP in macrophages treated with UA. Transcriptomic profiling revealed TXNIP as one of the most upregulated genes, and subsequent RT-PCR and Western blot analyses confirmed that TXNIP was upregulated by HUA. HUA treatment significantly increased mitochondrial reactive oxygen species (MtROS) levels and decreased insulin-stimulated glucose uptake. Silencing TXNIP by RNA interference significantly diminished HUA-induced oxidative stress and IR. Mechanistically, silencing TXNIP reversed the inhibition of the phosphorylation of insulin receptor substrate 2 (IRS2)/protein kinase B (AKT) pathway induced by HUA. Additional study revealed that HUA induced the activation of the nuclear factor erythroid 2-related factor 2 (Nrf2)/heme oxygenase 1 (HO-1) signaling pathway, but silencing TXNIP abolished it. Moreover, Nrf2 inhibitor (ML385) ameliorated HUA-induced IR independent of IRS2/AKT signaling. Probenecid, a well-known UA-lowering drug, significantly suppressed the activation of TXNIP and Nrf2/HO-1 signaling. Furthermore, RNA-seq revealed that activation of the TXNIP-related redox pathway may be a key regulator in patients with asymptomatic hyperuricemia. These data suggest that silencing TXNIP could ameliorate HUA-induced IR via the IRS2/AKT and Nrf2/HO-1 pathways in macrophages. Additionally, TXNIP might be a promising therapeutic target for preventing and treating oxidative stress and IR induced by HUA.
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Affiliation(s)
- Wei Yu
- Department of Internal Medicine, Xiang'an Hospital of Xiamen University, School of Medicine Xiamen University, Xiamen, China
| | - Chunjuan Chen
- Department of Cardiology, The Second Affiliated Hospital of Shantou University Medical College, Shantou, China
| | - Wanling Zhuang
- Department of Hematology, The First Affiliated Hospital of Shantou University Medical College, Shantou, China
| | - Wei Wang
- Department of Internal Medicine, Xiang'an Hospital of Xiamen University, School of Medicine Xiamen University, Xiamen, China
| | - Weidong Liu
- Department of Internal Medicine, Xiang'an Hospital of Xiamen University, School of Medicine Xiamen University, Xiamen, China
| | - Hairong Zhao
- Department of Internal Medicine, Xiang'an Hospital of Xiamen University, School of Medicine Xiamen University, Xiamen, China
| | - Jiaming Lv
- Department of Internal Medicine, Xiang'an Hospital of Xiamen University, School of Medicine Xiamen University, Xiamen, China
| | - De Xie
- Department of Internal Medicine, Xiang'an Hospital of Xiamen University, School of Medicine Xiamen University, Xiamen, China
| | - Qiang Wang
- Department of Internal Medicine, Xiang'an Hospital of Xiamen University, School of Medicine Xiamen University, Xiamen, China
| | - Furong He
- Department of Internal Medicine, Xiang'an Hospital of Xiamen University, School of Medicine Xiamen University, Xiamen, China
| | - Chenxi Xu
- Department of Internal Medicine, Xiang'an Hospital of Xiamen University, School of Medicine Xiamen University, Xiamen, China
| | - Bingyang Chen
- Department of Internal Medicine, Xiang'an Hospital of Xiamen University, School of Medicine Xiamen University, Xiamen, China
| | - Tetsuya Yamamoto
- Department of Diabetes, Endocrinology and Clinical Immunology, Hyogo College of Medicine, Nishinomiya, Hyogo, Japan
| | - Hidenori Koyama
- Department of Diabetes, Endocrinology and Clinical Immunology, Hyogo College of Medicine, Nishinomiya, Hyogo, Japan
| | - Jidong Cheng
- Department of Internal Medicine, Xiang'an Hospital of Xiamen University, School of Medicine Xiamen University, Xiamen, China
- Department of Diabetes, Endocrinology and Clinical Immunology, Hyogo College of Medicine, Nishinomiya, Hyogo, Japan
- Xiamen Key Laboratory of Translational Medicine for Nucleic Acid Metabolism and Regulation, Xiamen, Fujian, China
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15
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Eraky SM, Ramadan NM, Abo El-Magd NF. Antidiabetic effects of quercetin and liraglutide combination through modulation of TXNIP/IRS-1/PI3K pathway. Cell Biochem Funct 2021; 40:90-102. [PMID: 34855213 DOI: 10.1002/cbf.3678] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2021] [Revised: 10/19/2021] [Accepted: 11/08/2021] [Indexed: 12/30/2022]
Abstract
The study was designed to assess the possible augmented antidiabetic effects of combining quercetin and liraglutide in a type 1 diabetes model, with emphasis on the contribution of hepatic thioredoxin interacting protein (TXNIP)/insulin receptor substrate 1 (IRS-1)/phosphatidyl inositol-3 kinase (PI3K) pathway. The wound-healing effects were also examined. Diabetes was induced by a single i.p STZ injection (55 mg/kg). Diabetic rats were treated with either quercetin (100 mg/kg/day, orally) or liraglutide (0.3 mg/kg/twice daily, S.C.) or their combination. Drugs were also applied topically on the wound. Blood glucose levels, serum albumin, total protein, total cholesterol and triglycerides were measured. Histopathological examination of the liver, pancreas and skin tissues was performed using haematoxylin and eosin staining. The hepatic malondialdehyde level was measured spectrophotometrically. Hepatic TXNIP and PI3K levels were measured by enzyme-linked immunsorbent assay (ELISA). Tissue expression of IRS-1 and phospho-IRS-1 (Ser 616) was assessed by immunohistochemistry. Quercetin, liraglutide and their combination effectively decreased blood glucose levels, improved lipid profile, upregulated albumin and total protein serum levels and reduced hepatic oxidative stress with the combination being most effective. Moreover, the combination group showed enhanced wound-healing effects and almost normalized hepatic and pancreatic histopathology. Quercetin and/or liraglutide significantly decreased TXNIP levels and serine phosphorylation of IRS-1 and increased PI3K levels compared to the diabetic untreated group. Interestingly, only the combination therapy normalized hepatic IRS-1 expression. The combination of quercetin and liraglutide showed enhanced antidiabetic effects, possibly through lowering hepatic TXNIP levels, with the resultant up-regulation of the IRS-1/PI3K pathway.
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Affiliation(s)
- Salma M Eraky
- Department of Biochemistry, Faculty of Pharmacy, Mansoura University, Mansoura, Egypt
| | - Nehal M Ramadan
- Clinical Pharmacology Department, Faculty of Medicine, Mansoura University, Mansoura, Egypt
| | - Nada F Abo El-Magd
- Department of Biochemistry, Faculty of Pharmacy, Mansoura University, Mansoura, Egypt
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16
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Chu Y, Widjaja J, Hong J, Dolo PR, Zhu X, Yao L. Effect of Sleeve Gastrectomy on Plasma Thioredoxin-Interacting Protein (TXNIP). Obes Surg 2021; 31:4829-4835. [PMID: 34370159 DOI: 10.1007/s11695-021-05649-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Revised: 07/28/2021] [Accepted: 07/30/2021] [Indexed: 02/03/2023]
Abstract
PURPOSE The mechanism in which bariatric surgery induces diabetes remission is still poorly understood. This study proposes Thioredoxin-interacting protein (TXNIP) as a possible factor for the anti-diabetic mechanism after sleeve gastrectomy (SG). MATERIALS AND METHODS Plasma TXNIP level in obesity patients with diabetes (T2D, N = 20), obesity patients without diabetes (NDO, N = 20), and patients without obesity and diabetes (lean, N = 10) were assessed before surgery and at 1 and 12 months after SG. RESULTS Preoperative TXNIP level was significantly higher in T2D (196.4 ± 76.0 pg/ml) and NDO (149.7 ± 94.1 pg/ml) patients when compared with lean patients (98.7 ± 22.7 pg/ml) (p-value < 0.05). At 1 month and 12 months postoperatively, the TXNIP levels were reduced significantly from the preoperative levels in the T2D and NDO patients (p-value < 0.05). Before surgery, a correlation between TXNIP and fasting blood glucose (FBG) (r2 = 0.1585, p-value = 0.0109), HbA1C (r2 = 0.2120, p-value = 0.0028), and insulin (r2 = 0.1217, p-value = 0.0274) was observed. At 12 months after surgery, the reduction of TXNIP was also correlated with the degree of FBG (r2 = 0.1038, p-value = 0.0426), HbA1C (r2 = 0.2459, p-value = 0.0011), and insulin (r2 = 0.1365, p-value = 0.0190) reduction. CONCLUSION Plasma TXNIP level is elevated in obesity patients with/without diabetes. SG resulted in a significant reduction of plasma TXNIP level which is correlated with the degree of FBG, HbA1C, and insulin reduction. Regulation of TXNIP could be part of the mechanism of diabetes remission after bariatric surgery.
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Affiliation(s)
- Yuxiao Chu
- Department of Gastrointestinal Surgery, The Affiliated Hospital of Xuzhou Medical University, Xuzhou, Jiangsu, 221002, People's Republic of China
| | - Jason Widjaja
- Department of Gastrointestinal Surgery, The Affiliated Hospital of Xuzhou Medical University, Xuzhou, Jiangsu, 221002, People's Republic of China
| | - Jian Hong
- Department of Gastrointestinal Surgery, The Affiliated Hospital of Xuzhou Medical University, Xuzhou, Jiangsu, 221002, People's Republic of China
| | - Ponnie Robertlee Dolo
- Department of Gastrointestinal Surgery, The Affiliated Hospital of Xuzhou Medical University, Xuzhou, Jiangsu, 221002, People's Republic of China
| | - Xiaocheng Zhu
- Department of Gastrointestinal Surgery, The Affiliated Hospital of Xuzhou Medical University, Xuzhou, Jiangsu, 221002, People's Republic of China
| | - Libin Yao
- Department of Gastrointestinal Surgery, The Affiliated Hospital of Xuzhou Medical University, Xuzhou, Jiangsu, 221002, People's Republic of China.
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17
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Waldhart AN, Muhire B, Johnson B, Pettinga D, Madaj ZB, Wolfrum E, Dykstra H, Wegert V, Pospisilik JA, Han X, Wu N. Excess dietary carbohydrate affects mitochondrial integrity as observed in brown adipose tissue. Cell Rep 2021; 36:109488. [PMID: 34348139 PMCID: PMC8449951 DOI: 10.1016/j.celrep.2021.109488] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2020] [Revised: 02/05/2021] [Accepted: 07/13/2021] [Indexed: 12/17/2022] Open
Abstract
Hyperglycemia affects over 400 million individuals worldwide. The detrimental health effects are well studied at the tissue level, but the in vivo effects at the organelle level are poorly understood. To establish such an in vivo model, we used mice lacking TXNIP, a negative regulator of glucose uptake. Examining mitochondrial function in brown adipose tissue, we find that TXNIP KO mice have a lower content of polyunsaturated fatty acids (PUFAs) in their membrane lipids, which affects mitochondrial integrity and electron transport chain efficiency and ultimately results in lower mitochondrial heat output. This phenotype can be rescued by a ketogenic diet, confirming the usefulness of this model and highlighting one facet of early cellular damage caused by excess glucose influx.
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Affiliation(s)
| | | | - Ben Johnson
- Van Andel Institute, Grand Rapids, MI 49503, USA
| | | | | | | | | | | | | | - Xianlin Han
- Barshop Institute for Longevity and Aging Studies, UT Health San Antonio, San Antonio, TX 78229, USA; Department of Medicine, UT Health San Antonio, San Antonio, TX 78229, USA
| | - Ning Wu
- Van Andel Institute, Grand Rapids, MI 49503, USA.
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Agamennone M, Nicoli A, Bayer S, Weber V, Borro L, Gupta S, Fantacuzzi M, Di Pizio A. Protein-protein interactions at a glance: Protocols for the visualization of biomolecular interactions. Methods Cell Biol 2021; 166:271-307. [PMID: 34752337 DOI: 10.1016/bs.mcb.2021.06.012] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Protein-protein interactions (PPIs) play a key role in many biological processes and are intriguing targets for drug discovery campaigns. Advancements in experimental and computational techniques are leading to a growth of data accessibility, and, with it, an increased need for the analysis of PPIs. In this respect, visualization tools are essential instruments to represent and analyze biomolecular interactions. In this chapter, we reviewed some of the available tools, highlighting their features, and describing their functions with practical information on their usage.
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Affiliation(s)
| | - Alessandro Nicoli
- Leibniz-Institute for Food Systems Biology at the Technical University of Munich, Freising, Germany
| | - Sebastian Bayer
- Leibniz-Institute for Food Systems Biology at the Technical University of Munich, Freising, Germany
| | - Verena Weber
- Leibniz-Institute for Food Systems Biology at the Technical University of Munich, Freising, Germany
| | - Luca Borro
- Department of Imaging, Advanced Cardiovascular Imaging Unit, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy
| | - Shailendra Gupta
- Department of Systems Biology and Bioinformatics, University of Rostock, Rostock, Germany
| | | | - Antonella Di Pizio
- Leibniz-Institute for Food Systems Biology at the Technical University of Munich, Freising, Germany.
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19
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Mukai N, Nakayama Y, Abdali SA, Yoshioka J. Cardiomyocyte-specific Txnip C247S mutation improves left ventricular functional reserve in streptozotocin-induced diabetic mice. Am J Physiol Heart Circ Physiol 2021; 321:H259-H274. [PMID: 34085839 DOI: 10.1152/ajpheart.00174.2021] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Underlying molecular mechanisms for the development of diabetic cardiomyopathy remain to be determined. Long-term exposure to hyperglycemia causes oxidative stress, which leads to cardiomyocyte dysfunction. Previous studies established the importance of thioredoxin-interacting protein (Txnip) in cellular redox homeostasis and glucose metabolism. Txnip is a highly glucose-responsive molecule that interacts with the catalytic center of reduced thioredoxin and inhibits the antioxidant function of thioredoxin. Here, we show that the molecular interaction between Txnip and thioredoxin plays a pivotal role in the regulation of redox balance in the diabetic myocardium. High glucose increased Txnip expression, decreased thioredoxin activities, and caused oxidative stress in cells. The Txnip-thioredoxin complex was detected in cells with overexpressing wild-type Txnip but not Txnip cysteine 247 to serine (C247S) mutant that disrupts the intermolecular disulfide bridge. Then, diabetes was induced in cardiomyocyte-specific Txnip C247S knock-in mice and their littermate control animals by injections of streptozotocin (STZ). Prolonged hyperglycemia upregulated myocardial Txnip expression in both genotypes. The absence of Txnip's inhibition of thioredoxin in Txnip C247S mutant hearts promoted mitochondrial antioxidative capacities in cardiomyocytes, thereby protecting the heart from oxidative damage by diabetes. Stress hemodynamic analysis uncovered that Txnip C247S knock-in hearts have a greater left ventricular contractile reserve than wild-type hearts under STZ-induced diabetic conditions. These results provide novel evidence that Txnip serves as a regulator of hyperglycemia-induced cardiomyocyte toxicities through direct inhibition of thioredoxin and identify the single cysteine residue in Txnip as a therapeutic target for diabetic injuries.NEW & NORTEWORTHY Thioredoxin-interacting protein (Txnip) has been of great interest as a molecular mechanism to mediate diabetic organ damage. Here, we provide novel evidence that a single mutation of Txnip confers a defense mechanism against myocardial oxidative stress in streptozotocin-induced diabetic mice. The results demonstrate the importance of Txnip as a cysteine-containing redox protein that regulates antioxidant thioredoxin via disulfide bond-switching mechanism and identify the cysteine in Txnip as a therapeutic target for diabetic cardiomyopathy.
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Affiliation(s)
- Nobuhiro Mukai
- Department of Molecular, Cellular and Biomedical Sciences, City University of New York School of Medicine, City College of New York, New York, New York
| | - Yoshinobu Nakayama
- Department of Molecular, Cellular and Biomedical Sciences, City University of New York School of Medicine, City College of New York, New York, New York
| | - Syed Amir Abdali
- Department of Molecular, Cellular and Biomedical Sciences, City University of New York School of Medicine, City College of New York, New York, New York
| | - Jun Yoshioka
- Department of Molecular, Cellular and Biomedical Sciences, City University of New York School of Medicine, City College of New York, New York, New York
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20
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Nakayama Y, Mukai N, Wang BF, Yang K, Patwari P, Kitsis RN, Yoshioka J. Txnip C247S mutation protects the heart against acute myocardial infarction. J Mol Cell Cardiol 2021; 155:36-49. [PMID: 33652022 DOI: 10.1016/j.yjmcc.2021.02.013] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/19/2020] [Revised: 02/11/2021] [Accepted: 02/20/2021] [Indexed: 01/15/2023]
Abstract
RATIONALE Thioredoxin-interacting protein (Txnip) is a novel molecular target with translational potential in diverse human diseases. Txnip has several established cellular actions including binding to thioredoxin, a scavenger of reactive oxygen species (ROS). It has been long recognized from in vitro evidence that Txnip forms a disulfide bridge through cysteine 247 (C247) with reduced thioredoxin to inhibit the anti-oxidative properties of thioredoxin. However, the physiological significance of the Txnip-thioredoxin interaction remains largely undefined in vivo. OBJECTIVE A single mutation of Txnip, C247S, abolishes the binding of Txnip with thioredoxin. Using a conditional and inducible approach with a mouse model of a mutant Txnip that does not bind thioredoxin, we tested whether the interaction of thioredoxin with Txnip is required for Txnip's pro-oxidative or cytotoxic effects in the heart. METHODS AND RESULTS Overexpression of Txnip C247S in cells resulted in a reduction in ROS, due to an inability to inhibit thioredoxin. Hypoxia (1% O2, 24 h)-induced killing effects of Txnip were decreased by lower levels of cellular ROS in Txnip C247S-expressing cells compared with wild-type Txnip-expressing cells. Then, myocardial ischemic injuries were assessed in the animal model. Cardiomyocyte-specific Txnip C247S knock-in mice had better survival with smaller infarct size following myocardial infarction (MI) compared to control animals. The absence of Txnip's inhibition of thioredoxin promoted mitochondrial anti-oxidative capacities in cardiomyocytes, thereby protecting the heart from oxidative damage induced by MI. Furthermore, an unbiased RNA sequencing screen identified that hypoxia-inducible factor 1 signaling pathway was involved in Txnip C247S-mediated cardioprotective mechanisms. CONCLUSION Txnip is a cysteine-containing redox protein that robustly regulates the thioredoxin system via a disulfide bond-switching mechanism in adult cardiomyocytes. Our results provide the direct in vivo evidence that regulation of redox state by Txnip is a crucial component for myocardial homeostasis under ischemic stress.
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Affiliation(s)
- Yoshinobu Nakayama
- Department of Molecular, Cellular & Biomedical Sciences, City University of New York School of Medicine, City College of New York, NY, New York, United States of America
| | - Nobuhiro Mukai
- Department of Molecular, Cellular & Biomedical Sciences, City University of New York School of Medicine, City College of New York, NY, New York, United States of America
| | - Bing F Wang
- Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, United States of America
| | - Kristen Yang
- Department of Molecular, Cellular & Biomedical Sciences, City University of New York School of Medicine, City College of New York, NY, New York, United States of America
| | - Parth Patwari
- Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, United States of America
| | - Richard N Kitsis
- Departments of Medicine and Cell Biology, Wilf Family Cardiovascular Research Institute, Albert Einstein College of Medicine, Bronx, NY, United States of America
| | - Jun Yoshioka
- Department of Molecular, Cellular & Biomedical Sciences, City University of New York School of Medicine, City College of New York, NY, New York, United States of America; Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, United States of America.
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21
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Zhao W, Pu M, Shen S, Yin F. Geniposide improves insulin resistance through AMPK-mediated Txnip protein degradation in 3T3-L1 adipocytes. Acta Biochim Biophys Sin (Shanghai) 2021; 53:160-169. [PMID: 33349852 DOI: 10.1093/abbs/gmaa157] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2020] [Indexed: 12/29/2022] Open
Abstract
Thioredoxin-interacting protein (Txnip) has emerged as a key regulator of insulin resistance. In this study, we investigated the roles of geniposide and Txnip in insulin resistance in differentiated 3T3-L1 adipocytes. Our results revealed that geniposide markedly enhanced glucose uptake, increased the protein levels of insulin receptor substrate (IRS)-1 and GLUT-1, and prevented the phosphorylation of IRS-1 and Akt Thr308 induced by insulin resistance in 3T3-L1 adipocytes. We also observed that geniposide accelerated protein degradation of Txnip through proteasome pathway, and knockdown of Txnip with small interfering RNA attenuated the effect of geniposide on insulin signaling molecules, implying that Txnip played a pivotal role in the regulation of insulin signaling molecules by geniposide in 3T3-L1 adipocytes. Furthermore, geniposide induced the phosphorylation of adenosine monophosphate-activated protein kinase (AMPK) in the presence of high glucose in differentiated 3T3-L1 adipocytes, while compound C, an inhibitor of AMPK, prevented the effect of geniposide on Txnip degradation and the regulation of glucose uptake and insulin signaling molecules including p-IRS-1, IRS-1, and GLUT-1 in differentiated 3T3-L1 adipocytes. Taken together, all these findings suggest that geniposide improves the insulin signaling defect possibly by AMPK-mediated Txnip degradation in 3T3-L1 adipocytes.
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Affiliation(s)
- Wanjun Zhao
- Chongqing Key Lab of Medicinal Chemistry & Molecular Pharmacology of Technology, Chongqing University of Technology, Chongqing 400054, China
| | - Mengru Pu
- Chongqing Key Lab of Medicinal Chemistry & Molecular Pharmacology of Technology, Chongqing University of Technology, Chongqing 400054, China
| | - Shenli Shen
- Chongqing Key Lab of Medicinal Chemistry & Molecular Pharmacology of Technology, Chongqing University of Technology, Chongqing 400054, China
| | - Fei Yin
- Chongqing Key Lab of Medicinal Chemistry & Molecular Pharmacology of Technology, Chongqing University of Technology, Chongqing 400054, China
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22
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Gora IM, Ciechanowska A, Ladyzynski P. NLRP3 Inflammasome at the Interface of Inflammation, Endothelial Dysfunction, and Type 2 Diabetes. Cells 2021; 10:314. [PMID: 33546399 PMCID: PMC7913585 DOI: 10.3390/cells10020314] [Citation(s) in RCA: 52] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2020] [Revised: 01/24/2021] [Accepted: 01/30/2021] [Indexed: 01/08/2023] Open
Abstract
Type 2 diabetes mellitus (T2DM), accounting for 90-95% cases of diabetes, is characterized by chronic inflammation. The mechanisms that control inflammation activation in T2DM are largely unexplored. Inflammasomes represent significant sensors mediating innate immune responses. The aim of this work is to present a review of links between the NLRP3 inflammasome, endothelial dysfunction, and T2DM. The NLRP3 inflammasome activates caspase-1, which leads to the maturation of pro-inflammatory cytokines interleukin 1β and interleukin 18. In this review, we characterize the structure and functions of NLRP3 inflammasome as well as the most important mechanisms and molecules engaged in its activation. We present evidence of the importance of the endothelial dysfunction as the first key step to activating the inflammasome, which suggests that suppressing the NLRP3 inflammasome could be a new approach in depletion hyperglycemic toxicity and in averting the onset of vascular complications in T2DM. We also demonstrate reports showing that the expression of a few microRNAs that are also known to be involved in either NLRP3 inflammasome activation or endothelial dysfunction is deregulated in T2DM. Collectively, this evidence suggests that T2DM is an inflammatory disease stimulated by pro-inflammatory cytokines. Finally, studies revealing the role of glucose concentration in the activation of NLRP3 inflammasome are analyzed. The more that is known about inflammasomes, the higher the chances to create new, effective therapies for patients suffering from inflammatory diseases. This may offer potential novel therapeutic perspectives in T2DM prevention and treatment.
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Affiliation(s)
- Ilona M. Gora
- Nalecz Institute of Biocybernetics and Biomedical Engineering, Polish Academy of Sciences, Ks. Trojdena 4, 02-109 Warsaw, Poland; (A.C.); (P.L.)
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23
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Joshi H, Vastrad B, Joshi N, Vastrad C, Tengli A, Kotturshetti I. Identification of Key Pathways and Genes in Obesity Using Bioinformatics Analysis and Molecular Docking Studies. Front Endocrinol (Lausanne) 2021; 12:628907. [PMID: 34248836 PMCID: PMC8264660 DOI: 10.3389/fendo.2021.628907] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/13/2020] [Accepted: 05/19/2021] [Indexed: 01/01/2023] Open
Abstract
Obesity is an excess accumulation of body fat. Its progression rate has remained high in recent years. Therefore, the aim of this study was to diagnose important differentially expressed genes (DEGs) associated in its development, which may be used as novel biomarkers or potential therapeutic targets for obesity. The gene expression profile of E-MTAB-6728 was downloaded from the database. After screening DEGs in each ArrayExpress dataset, we further used the robust rank aggregation method to diagnose 876 significant DEGs including 438 up regulated and 438 down regulated genes. Functional enrichment analysis was performed. These DEGs were shown to be significantly enriched in different obesity related pathways and GO functions. Then protein-protein interaction network, target genes - miRNA regulatory network and target genes - TF regulatory network were constructed and analyzed. The module analysis was performed based on the whole PPI network. We finally filtered out STAT3, CORO1C, SERPINH1, MVP, ITGB5, PCM1, SIRT1, EEF1G, PTEN and RPS2 hub genes. Hub genes were validated by ICH analysis, receiver operating curve (ROC) analysis and RT-PCR. Finally a molecular docking study was performed to find small drug molecules. The robust DEGs linked with the development of obesity were screened through the expression profile, and integrated bioinformatics analysis was conducted. Our study provides reliable molecular biomarkers for screening and diagnosis, prognosis as well as novel therapeutic targets for obesity.
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Affiliation(s)
- Harish Joshi
- Department of Endocrinology, Endocrine and Diabetes Care Center, Hubbali, India
| | - Basavaraj Vastrad
- Department of Biochemistry, Basaveshwar College of Pharmacy, Gadag, India
| | - Nidhi Joshi
- Department of Medicine, Dr. D. Y. Patil Medical College, Kolhapur, India
| | - Chanabasayya Vastrad
- Biostatistics and Bioinformatics, Chanabasava Nilaya, Bharthinagar, Dharwad, India
- *Correspondence: Chanabasayya Vastrad,
| | - Anandkumar Tengli
- Department of Pharmaceutical Chemistry, JSS College of Pharmacy, Mysuru and JSS Academy of Higher Education & Research, Mysuru, India
| | - Iranna Kotturshetti
- Department of Ayurveda, Rajiv Gandhi Education Society`s Ayurvedic Medical College, Ron, India
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24
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Thioredoxin-Interacting Protein (TXNIP) with Focus on Brain and Neurodegenerative Diseases. Int J Mol Sci 2020; 21:ijms21249357. [PMID: 33302545 PMCID: PMC7764580 DOI: 10.3390/ijms21249357] [Citation(s) in RCA: 69] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2020] [Revised: 12/02/2020] [Accepted: 12/03/2020] [Indexed: 12/11/2022] Open
Abstract
The development of new therapeutic approaches to diseases relies on the identification of key molecular targets involved in amplifying disease processes. One such molecule is thioredoxin-interacting protein (TXNIP), also designated thioredoxin-binding protein-2 (TBP-2), a member of the α-arrestin family of proteins and a central regulator of glucose and lipid metabolism, involved in diabetes-associated vascular endothelial dysfunction and inflammation. TXNIP sequesters reduced thioredoxin (TRX), inhibiting its function, resulting in increased oxidative stress. Many different cellular stress factors regulate TXNIP expression, including high glucose, endoplasmic reticulum stress, free radicals, hypoxia, nitric oxide, insulin, and adenosine-containing molecules. TXNIP is also directly involved in inflammatory activation through its interaction with the nucleotide-binding domain, leucine-rich-containing family, and pyrin domain-containing-3 (NLRP3) inflammasome complex. Neurodegenerative diseases such as Alzheimer’s disease have significant pathologies associated with increased oxidative stress, inflammation, and vascular dysfunctions. In addition, as dysfunctions in glucose and cellular metabolism have been associated with such brain diseases, a role for TXNIP in neurodegeneration has actively been investigated. In this review, we will focus on the current state of the understanding of possible normal and pathological functions of TXNIP in the central nervous system from studies of in vitro neural cells and the brains of humans and experimental animals with reference to other studies. As TXNIP can be expressed by neurons, microglia, astrocytes, and endothelial cells, a complex pattern of regulation and function in the brain is suggested. We will examine data suggesting TXNIP as a therapeutic target for neurodegenerative diseases where further research is needed.
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Deng W, Li Y, Ren Z, He Q, Jia Y, Liu Y, Zhang W, Gan X, Liu D. Thioredoxin-interacting protein: a critical link between autophagy disorders and pancreatic β-cell dysfunction. Endocrine 2020; 70:526-537. [PMID: 32892310 DOI: 10.1007/s12020-020-02471-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/28/2019] [Accepted: 08/23/2020] [Indexed: 12/18/2022]
Abstract
Thioredoxin-interacting protein (TXNIP) is a known important regulatory protein of islet β-cell biology and function, but the detailed mechanism is not clear. Autophagy plays a pivotal role in maintaining cellular homoeostasis. This study aimed to elucidate the influence of TXNIP on the autophagy of β-cell. In this study, C57BL/6 mice and TXNIP-/- mice were fed with a standard diet (SD) or a high-fat and high-sugar diet (HFSD), and then we analysed biochemical and autophagy related indexes in the mice. We infected MIN6 cells with LV-TXNIP and siRNA TXNIP, then the cells were treated with free fatty acid (FFA), autophagic activator rapamycin (RAP), inhibitors of autophagy chloroquine (CQ) and bafilomycin A1(BAF), finally, we examined the changes of autophagy in MIN6 cells. The results showed that HFSD led to β-cell dysfunction and autophagy dysregulation, which was improved by TXNIP knockout in mice. In vitro experiments, TXNIP gene silencing enhanced LC3B-I conversion to LC3B-II, reduced the protein level of P62, decreased autophagosome accumulation induced by FFA treatment, increased the glucose-stimulated insulin secretion (GSIS) and autophagic flux inhibited by treatment with CQ. TXNIP overexpression induced upregulation of LC3B-I, LC3B-II and P62, accentuating the increase in autophagy and organelle destruction induced by FFA, and exacerbated the effect of BAF on the accumulation of autophagy proteins. Increasing TXNIP levels reduced GSIS, which was reversed by treatment with RAP. In summary, our study suggested that TXNIP is a critical link between autophagy disorders and pancreatic β-cell dysfunction.
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Affiliation(s)
- Wenzhen Deng
- Department of Endocrinology, The Second Affiliated Hospital of Chongqing Medical University, 400010, Chongqing, China
- Department of Endocrinology, Qianjiang Central Hospital of Chongqing, 409000, Chongqing, China
| | - Yang Li
- Department of Endocrinology, The Second Affiliated Hospital of Chongqing Medical University, 400010, Chongqing, China
| | - Ziyu Ren
- Department of Endocrinology, The Second Affiliated Hospital of Chongqing Medical University, 400010, Chongqing, China
| | - Qirui He
- Department of Endocrinology, The Second Affiliated Hospital of Chongqing Medical University, 400010, Chongqing, China
| | - Yanjun Jia
- Department of Endocrinology, The Second Affiliated Hospital of Chongqing Medical University, 400010, Chongqing, China
| | - Yongjian Liu
- Department of Endocrinology, The Second Affiliated Hospital of Chongqing Medical University, 400010, Chongqing, China
| | - Weiwei Zhang
- Department of Endocrinology, The Second Affiliated Hospital of Chongqing Medical University, 400010, Chongqing, China
| | - Xianfeng Gan
- Department of Hepatobiliary Surgery, Sichuan Academy of Medical Sciences and Sichuan Provincial People's Hospital, 610072, Chengdu, China.
| | - Dongfang Liu
- Department of Endocrinology, The Second Affiliated Hospital of Chongqing Medical University, 400010, Chongqing, China.
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Liang R, Wang M, Fu C, Liang H, Deng H, Tan Y, Xu F, Cai M. Liraglutide protects against high-fat diet-induced kidney injury by ameliorating apoptosis. Endocr Connect 2020; 9:946-954. [PMID: 33027757 PMCID: PMC7583131 DOI: 10.1530/ec-20-0294] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/13/2020] [Accepted: 09/03/2020] [Indexed: 12/16/2022]
Abstract
BACKGROUND Obesity is associated with the development and progression of chronic kidney disease. Emerging evidence suggests that glucagon-like peptide-1 receptor agonist could reduce renal damage and albuminuria. Sirtuin 1 (SIRT1) was considered as a crucial regulator in metabolism-related kidney disease. Herein, the role of SIRT1 in liraglutide-ameliorated high-fat diet (HFD)-induced kidney injury was illustrated. METHODS Male C57BL/6 mice were fed HFD for 20 weeks to induce kidney injury that was then treated with liraglutide for 8 weeks to estimate its protective effect on the kidney. Also, the mechanism of the drug in SV40 MES 13 (SV40) mouse mesangial cells was elucidated. RESULTS Liraglutide treatment ameliorated HFD-induced metabolic disorders, including hyperglycemia, increasing body weight, and insulin resistance. In addition, kidney weight, urine albumin-to-creatinine, and kidney morphological changes such as vacuolated tubules, glomerulomegaly, thickened glomerular basement membrane, and tubulointerstitial fibrosis were also significantly ameliorated. Furthermore, apoptotic cells and apoptosis markers were downregulated in the kidney of liraglutide-treated mice. In addition, the expression of SIRT1 protein was upregulated, whereas thioredoxin-interacting protein (TXNIP), which serves as a mediator of oxidative stress and apoptosis in metabolism disease, was downregulated by liraglutide. In SV40 cells, the effect of liraglutide on reversing the upregulation of cleaved caspase-3 induced by high glucose (30 mM) was hampered when SIRT1 was knocked down; also, the downregulation of TXNIP by liraglutide was blocked. CONCLUSIONS Liraglutide might have a beneficial effect on metabolism-related kidney damage by inhibiting apoptosis via activation of SIRT1 and suppression of TXNIP pathway.
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Affiliation(s)
- Riying Liang
- Department of Endocrinology and Metabolism, The Third Affiliated Hospital of Sun Yat-Sen University, Guangzhou, China
- Guangdong Provincial Key Laboratory of Diabetology, Guangzhou, China
- Department of Ultrasound, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, China
| | - Meijun Wang
- Department of Endocrinology and Metabolism, The Third Affiliated Hospital of Sun Yat-Sen University, Guangzhou, China
- Guangdong Provincial Key Laboratory of Diabetology, Guangzhou, China
| | - Chang Fu
- Department of Endocrinology and Metabolism, The Third Affiliated Hospital of Sun Yat-Sen University, Guangzhou, China
- Guangdong Provincial Key Laboratory of Diabetology, Guangzhou, China
| | - Hua Liang
- Department of Endocrinology and Metabolism, The Third Affiliated Hospital of Sun Yat-Sen University, Guangzhou, China
- Guangdong Provincial Key Laboratory of Diabetology, Guangzhou, China
| | - Hongrong Deng
- Department of Endocrinology and Metabolism, The Third Affiliated Hospital of Sun Yat-Sen University, Guangzhou, China
- Guangdong Provincial Key Laboratory of Diabetology, Guangzhou, China
| | - Ying Tan
- Department of Endocrinology and Metabolism, The Third Affiliated Hospital of Sun Yat-Sen University, Guangzhou, China
- Guangdong Provincial Key Laboratory of Diabetology, Guangzhou, China
| | - Fen Xu
- Department of Endocrinology and Metabolism, The Third Affiliated Hospital of Sun Yat-Sen University, Guangzhou, China
- Guangdong Provincial Key Laboratory of Diabetology, Guangzhou, China
| | - Mengyin Cai
- Department of Endocrinology and Metabolism, The Third Affiliated Hospital of Sun Yat-Sen University, Guangzhou, China
- Guangdong Provincial Key Laboratory of Diabetology, Guangzhou, China
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Wargent ET, Martin-Gronert MS, Cripps RL, Heisler LK, Yeo GSH, Ozanne SE, Arch JRS, Stocker CJ. Developmental programming of appetite and growth in male rats increases hypothalamic serotonin (5-HT)5A receptor expression and sensitivity. Int J Obes (Lond) 2020; 44:1946-1957. [PMID: 32719434 DOI: 10.1038/s41366-020-0643-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/04/2019] [Revised: 06/23/2020] [Accepted: 07/16/2020] [Indexed: 11/08/2022]
Abstract
BACKGROUND Though it is well established that neonatal nutrition plays a major role in lifelong offspring health, the mechanisms underpinning this have not been well defined. Early postnatal accelerated growth resulting from maternal nutritional status is associated with increased appetite and body weight. Likewise, slow growth correlates with decreased appetite and body weight. Food consumption and food-seeking behaviour are directly modulated by central serotonergic (5-hydroxytryptamine, 5-HT) pathways. This study examined the effect of a rat maternal postnatal low protein (PLP) diet on 5-HT receptor mediated food intake in offspring. METHODS Microarray analyses, in situ hybridization or laser capture microdissection of the ARC followed by RT-PCR were used to identify genes up- or down-regulated in the arcuate nucleus of the hypothalamus (ARC) of 3-month-old male PLP rats. Third ventricle cannulation was used to identify altered sensitivity to serotonin receptor agonists and antagonists with respect to food intake. RESULTS Male PLP offspring consumed less food and had lower growth rates up to 3 months of age compared with Control offspring from dams fed a normal diet. In total, 97 genes were upregulated including the 5-HT5A receptor (5-HT5AR) and 149 downregulated genes in PLP rats compared with Controls. The former obesity medication fenfluramine and the 5-HT receptor agonist 5-Carboxamidotryptamine (5-CT) significantly suppressed food intake in both groups, but the PLP offspring were more sensitive to d-fenfluramine and 5-CT compared with Controls. The effect of 5-CT was antagonized by the 5-HT5AR antagonist SB699551. 5-CT also reduced NPY-induced hyperphagia in both Control and PLP rats but was more effective in PLP offspring. CONCLUSIONS Postnatal low protein programming of growth in rats enhances the central effects of serotonin on appetite by increasing hypothalamic 5-HT5AR expression and sensitivity. These findings provide insight into the possible mechanisms through which a maternal low protein diet during lactation programs reduced growth and appetite in offspring.
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Affiliation(s)
- Edward T Wargent
- Buckingham Institute of Translational Medicine, University of Buckingham, Hunter Street, Buckingham, MK18 1EG, UK
| | - Malgorzata S Martin-Gronert
- Metabolic Research Laboratories, Wellcome Trust-MRC Institute of Metabolic Science, University of Cambridge, Addenbrooke's Hospital, Cambridge, CB2 0QQ, UK
| | - Roselle L Cripps
- Metabolic Research Laboratories, Wellcome Trust-MRC Institute of Metabolic Science, University of Cambridge, Addenbrooke's Hospital, Cambridge, CB2 0QQ, UK
| | - Lora K Heisler
- The Rowett, Institute, University of Aberdeen, Aberdeen, AB25 2ZD, UK
| | - Giles S H Yeo
- Metabolic Research Laboratories, Wellcome Trust-MRC Institute of Metabolic Science, University of Cambridge, Addenbrooke's Hospital, Cambridge, CB2 0QQ, UK
| | - Susan E Ozanne
- Metabolic Research Laboratories, Wellcome Trust-MRC Institute of Metabolic Science, University of Cambridge, Addenbrooke's Hospital, Cambridge, CB2 0QQ, UK
| | - Jonathan R S Arch
- Buckingham Institute of Translational Medicine, University of Buckingham, Hunter Street, Buckingham, MK18 1EG, UK
| | - Claire J Stocker
- Buckingham Institute of Translational Medicine, University of Buckingham, Hunter Street, Buckingham, MK18 1EG, UK.
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Yoshihara E. TXNIP/TBP-2: A Master Regulator for Glucose Homeostasis. Antioxidants (Basel) 2020; 9:E765. [PMID: 32824669 PMCID: PMC7464905 DOI: 10.3390/antiox9080765] [Citation(s) in RCA: 50] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 08/09/2020] [Accepted: 08/10/2020] [Indexed: 02/07/2023] Open
Abstract
Identification of thioredoxin binding protein-2 (TBP-2), which is currently known as thioredoxin interacting protein (TXNIP), as an important binding partner for thioredoxin (TRX) revealed that an evolutionarily conserved reduction-oxidation (redox) signal complex plays an important role for pathophysiology. Due to the reducing activity of TRX, the TRX/TXNIP signal complex has been shown to be an important regulator for redox-related signal transduction in many types of cells in various species. In addition to its role in redox-dependent regulation, TXNIP has cellular functions that are performed in a redox-independent manner, which largely rely on their scaffolding function as an ancestral α-Arrestin family. Both the redox-dependent and -independent TXNIP functions serve as regulatory pathways in glucose metabolism. This review highlights the key advances in understanding TXNIP function as a master regulator for whole-body glucose homeostasis. The potential for therapeutic advantages of targeting TXNIP in diabetes and the future direction of the study are also discussed.
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Affiliation(s)
- Eiji Yoshihara
- The Lundquist Institute for Biomedical Innovation at Harbor-UCLA Medical Center, Torrance, CA 90502, USA;
- David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
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Batista TM, Garcia-Martin R, Cai W, Konishi M, O'Neill BT, Sakaguchi M, Kim JH, Jung DY, Kim JK, Kahn CR. Multi-dimensional Transcriptional Remodeling by Physiological Insulin In Vivo. Cell Rep 2020; 26:3429-3443.e3. [PMID: 30893613 DOI: 10.1016/j.celrep.2019.02.081] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2018] [Revised: 01/11/2019] [Accepted: 02/21/2019] [Indexed: 12/12/2022] Open
Abstract
Regulation of gene expression is an important aspect of insulin action but in vivo is intertwined with changing levels of glucose and counter-regulatory hormones. Here we demonstrate that under euglycemic clamp conditions, physiological levels of insulin regulate interrelated networks of more than 1,000 transcripts in muscle and liver. These include expected pathways related to glucose and lipid utilization, mitochondrial function, and autophagy, as well as unexpected pathways, such as chromatin remodeling, mRNA splicing, and Notch signaling. These acutely regulated pathways extend beyond those dysregulated in mice with chronic insulin deficiency or insulin resistance and involve a broad network of transcription factors. More than 150 non-coding RNAs were regulated by insulin, many of which also responded to fasting and refeeding. Pathway analysis and RNAi knockdown revealed a role for lncRNA Gm15441 in regulating fatty acid oxidation in hepatocytes. Altogether, these changes in coding and non-coding RNAs provide an integrated transcriptional network underlying the complexity of insulin action.
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Affiliation(s)
- Thiago M Batista
- Section of Integrative Physiology and Metabolism, Joslin Diabetes Center, Harvard Medical School, Boston, MA 02215, USA
| | - Ruben Garcia-Martin
- Section of Integrative Physiology and Metabolism, Joslin Diabetes Center, Harvard Medical School, Boston, MA 02215, USA
| | - Weikang Cai
- Section of Integrative Physiology and Metabolism, Joslin Diabetes Center, Harvard Medical School, Boston, MA 02215, USA
| | - Masahiro Konishi
- Section of Integrative Physiology and Metabolism, Joslin Diabetes Center, Harvard Medical School, Boston, MA 02215, USA
| | - Brian T O'Neill
- Section of Integrative Physiology and Metabolism, Joslin Diabetes Center, Harvard Medical School, Boston, MA 02215, USA; Division of Endocrinology and Metabolism, Fraternal Order of Eagles Diabetes Research Center, University of Iowa Carver College of Medicine, Iowa City, IA, USA
| | - Masaji Sakaguchi
- Section of Integrative Physiology and Metabolism, Joslin Diabetes Center, Harvard Medical School, Boston, MA 02215, USA; Department of Metabolic Medicine, Kumamoto University, 1-1-1 Honjo, Chuoku, Kumamoto 860-8556, Japan
| | - Jong Hun Kim
- Program in Molecular Medicine, Department of Medicine, University of Massachusetts Medical School, Worcester, MA 01655, USA; Department of Food Science and Biotechnology, Sungshin University, Seoul 01133, Republic of Korea
| | - Dae Young Jung
- Program in Molecular Medicine, Department of Medicine, University of Massachusetts Medical School, Worcester, MA 01655, USA
| | - Jason K Kim
- Program in Molecular Medicine, Department of Medicine, University of Massachusetts Medical School, Worcester, MA 01655, USA; Division of Endocrinology, Metabolism, and Diabetes, Department of Medicine, University of Massachusetts Medical School, Worcester, MA 01655, USA
| | - C Ronald Kahn
- Section of Integrative Physiology and Metabolism, Joslin Diabetes Center, Harvard Medical School, Boston, MA 02215, USA.
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Arrestin domain-containing 3 (Arrdc3) modulates insulin action and glucose metabolism in liver. Proc Natl Acad Sci U S A 2020; 117:6733-6740. [PMID: 32156724 DOI: 10.1073/pnas.1922370117] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Insulin action in the liver is critical for glucose homeostasis through regulation of glycogen synthesis and glucose output. Arrestin domain-containing 3 (Arrdc3) is a member of the α-arrestin family previously linked to human obesity. Here, we show that Arrdc3 is differentially regulated by insulin in vivo in mice undergoing euglycemic-hyperinsulinemic clamps, being highly up-regulated in liver and down-regulated in muscle and fat. Mice with liver-specific knockout (KO) of the insulin receptor (IR) have a 50% reduction in Arrdc3 messenger RNA, while, conversely, mice with liver-specific KO of Arrdc3 (L-Arrdc3 KO) have increased IR protein in plasma membrane. This leads to increased hepatic insulin sensitivity with increased phosphorylation of FOXO1, reduced expression of PEPCK, and increased glucokinase expression resulting in reduced hepatic glucose production and increased hepatic glycogen accumulation. These effects are due to interaction of ARRDC3 with IR resulting in phosphorylation of ARRDC3 on a conserved tyrosine (Y382) in the carboxyl-terminal domain. Thus, Arrdc3 is an insulin target gene, and ARRDC3 protein directly interacts with IR to serve as a feedback regulator of insulin action in control of liver metabolism.
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Jiang X, Pang Y, Zhao S, Hao H, Zhao X, Du W, Wang Y, Zhu H. Thioredoxin-interacting protein regulates glucose metabolism and improves the intracellular redox state in bovine oocytes during in vitro maturation. Am J Physiol Endocrinol Metab 2020; 318:E405-E416. [PMID: 31935112 DOI: 10.1152/ajpendo.00057.2019] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The extent of glucose metabolism during oocyte maturation is closely related to oocyte developmental potential. Thioredoxin-interacting protein (TXNIP) is an α-arrestin family protein that negatively regulates glucose uptake into cells. However, little information is available regarding the function of TXNIP in bovine oocytes. Accordingly, the present study was performed to investigate the influence of TXNIP on glucose metabolism in bovine oocytes during in vitro maturation. Pharmacological inhibition of TXNIP by azaserine enhanced glucose uptake and imparted a specific metabolic effect on glycolysis and pentose phosphate pathway (PPP). RNA interference (RNAi) was adopted to further determine the biological significance of TXNIP in regulating glucose metabolism. The maturation rate and the developmental competence of TXNIP siRNA-treated oocytes were significantly improved. Knockdown of TXNIP in bovine oocytes significantly increased glycolysis by increasing the activities of phosphofructokinase (PFK), pyruvate kinase, and lactate dehydrogenase; pyruvate and lactate production; and intracellular ATP level, as well as mitochondrial activity. Furthermore, glucose metabolism through PPP was also enhanced by TXNIP depletion, as TXNIP siRNA treatment promoted glucose-6-phosphate dehydrogenase (G6PDH) activity and NADPH content, and helped maintain a high level of glutathione and a low level of reactive oxygen species within the oocytes. Further studies revealed that inhibition of TXNIP resulted increases in glucose transporter 1 (GLUT1) expression, as well as PFK1 platelet isoform (PFKP) and G6PDH mRNA levels. These results reveal that TXNIP depletion promotes oocyte maturation by enhancing both glycolysis and the PPP. During in vitro maturation of bovine oocytes, TXNIP serves as a key regulator of glucose uptake by controlling GLUT1 expression.
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Affiliation(s)
- XiaoLong Jiang
- Key Laboratory of Animal (Poultry) Genetics Breeding and Reproduction, Ministry of Agriculture and Rural Affairs, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing, People's Republic of China
- Key Laboratory of Agricultural Animal and Breeding, National Engineering Laboratory for Animal Breeding, College of Animal Science and Technology, China Agricultural University, Beijing, People's Republic of China
| | - YunWei Pang
- Key Laboratory of Animal (Poultry) Genetics Breeding and Reproduction, Ministry of Agriculture and Rural Affairs, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing, People's Republic of China
| | - ShanJiang Zhao
- Key Laboratory of Animal (Poultry) Genetics Breeding and Reproduction, Ministry of Agriculture and Rural Affairs, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing, People's Republic of China
| | - HaiSheng Hao
- Key Laboratory of Animal (Poultry) Genetics Breeding and Reproduction, Ministry of Agriculture and Rural Affairs, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing, People's Republic of China
| | - XueMing Zhao
- Key Laboratory of Animal (Poultry) Genetics Breeding and Reproduction, Ministry of Agriculture and Rural Affairs, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing, People's Republic of China
| | - WeiHua Du
- Key Laboratory of Animal (Poultry) Genetics Breeding and Reproduction, Ministry of Agriculture and Rural Affairs, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing, People's Republic of China
| | - YaChun Wang
- Key Laboratory of Agricultural Animal and Breeding, National Engineering Laboratory for Animal Breeding, College of Animal Science and Technology, China Agricultural University, Beijing, People's Republic of China
| | - HuaBin Zhu
- Key Laboratory of Animal (Poultry) Genetics Breeding and Reproduction, Ministry of Agriculture and Rural Affairs, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing, People's Republic of China
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Dafre AL, Schmitz AE, Maher P. Rapid and persistent loss of TXNIP in HT22 neuronal cells under carbonyl and hyperosmotic stress. Neurochem Int 2019; 132:104585. [PMID: 31678323 DOI: 10.1016/j.neuint.2019.104585] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2019] [Revised: 10/27/2019] [Accepted: 10/28/2019] [Indexed: 12/11/2022]
Abstract
Thioredoxin interacting protein (TXNIP) binds to thioredoxin thereby limiting its activity, but it also promotes internalization of glucose transporters, participates in inflammasome activation, and controls autophagy. Published data and this work demonstrate that TXNIP responds to a number of apparently unrelated stresses, such as serum deprivation, pH change, and oxidative, osmotic and carbonyl stress. Interestingly, we noticed that hyperosmotic (NaCl) and carbonyl (methylglyoxal, MGO) stresses in HT22 neuronal cells produced a rapid loss of TXNIP (half-life ∼12 min), prompting us to search for possible mechanisms controlling this TXNIP loss, including pH change, serum deprivation, calcium metabolism and inhibition of the proteasome and other proteases, autophagy and MAPKs. None of these routes stopped the TXNIP loss induced by hyperosmotic and carbonyl stress. Besides transcriptional, translational and microRNA regulation, there is evidence indicating that mTOR and AMPK also control TXNIP expression. Indeed, AMPK-deficient mouse embryonic fibroblasts failed to respond to phenformin (AMPK activator) and compound C (AMPK inhibitor), while rapamycin induced a marked increase in TXNIP levels, confirming the known AMPK/mTOR control over TXNIP. However, the TXNIP loss induced by NaCl or MGO were observed even in AMPK deficient MEFs or after mTOR inhibition, indicating AMPK/mTOR does not participate in this rapid TXNIP loss. These results suggest that rapid TXNIP loss is a general and immediate response to stress that can improve energy availability and antioxidant protection, eventually culminating in better cell survival.
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Affiliation(s)
- Alcir Luiz Dafre
- Biochemistry Department, Federal University of Santa Catarina, 88040-900, Florianópolis, SC, Brazil.
| | - Ariana Ern Schmitz
- Biochemistry Department, Federal University of Santa Catarina, 88040-900, Florianópolis, SC, Brazil
| | - Pamela Maher
- Cellular Neurobiology Laboratory, Salk Institute for Biological Studies, CA, 92037, La Jolla, United States.
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Hao Y, Shen S, Yin F, Zhang Y, Liu J. Unfolded protein response is involved in geniposide‐regulating glucose‐stimulated insulin secretion in INS‐1 cells. Cell Biochem Funct 2019; 37:368-376. [DOI: 10.1002/cbf.3414] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2018] [Accepted: 05/06/2019] [Indexed: 02/04/2023]
Affiliation(s)
- Yanan Hao
- Chongqing Key Laboratory of Medicinal Chemistry and Molecular PharmacologyChongqing University of Technology Chongqing China
| | - Shenli Shen
- Chongqing Key Laboratory of Medicinal Chemistry and Molecular PharmacologyChongqing University of Technology Chongqing China
| | - Fei Yin
- Chongqing Key Laboratory of Medicinal Chemistry and Molecular PharmacologyChongqing University of Technology Chongqing China
| | - Yonglan Zhang
- Chongqing Key Laboratory of Medicinal Chemistry and Molecular PharmacologyChongqing University of Technology Chongqing China
| | - Jianhui Liu
- Chongqing Key Laboratory of Medicinal Chemistry and Molecular PharmacologyChongqing University of Technology Chongqing China
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Katsu-Jiménez Y, Vázquez-Calvo C, Maffezzini C, Halldin M, Peng X, Freyer C, Wredenberg A, Giménez-Cassina A, Wedell A, Arnér ESJ. Absence of TXNIP in Humans Leads to Lactic Acidosis and Low Serum Methionine Linked to Deficient Respiration on Pyruvate. Diabetes 2019; 68:709-723. [PMID: 30755400 DOI: 10.2337/db18-0557] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/23/2018] [Accepted: 01/21/2019] [Indexed: 11/13/2022]
Abstract
Thioredoxin-interacting protein (TXNIP) is an α-arrestin that can bind to and inhibit the antioxidant protein thioredoxin (TXN). TXNIP expression is induced by glucose and promotes β-cell apoptosis in the pancreas, and deletion of its gene in mouse models protects against diabetes. TXNIP is currently studied as a potential new target for antidiabetic drug therapy. In this study, we describe a family with a mutation in the TXNIP gene leading to nondetectable expression of TXNIP protein. Symptoms of affected family members include lactic acidosis and low serum methionine levels. Using patient-derived TXNIP-deficient fibroblasts and myoblasts, we show that oxidative phosphorylation is impaired in these cells when given glucose and pyruvate but normalized with malate. Isolated mitochondria from these cells appear to have normal respiratory function. The cells also display a transcriptional pattern suggestive of a high basal activation of the Nrf2 transcription factor. We conclude that a complete lack of TXNIP in human is nonlethal and leads to specific metabolic distortions that are, at least in part, linked to a deficient respiration on pyruvate. The results give important insights into the impact of TXNIP in humans and thus help to further advance the development of antidiabetic drugs targeting this protein.
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Affiliation(s)
- Yurika Katsu-Jiménez
- Division of Biochemistry, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden
| | - Carmela Vázquez-Calvo
- Division of Biochemistry, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden
| | - Camilla Maffezzini
- Division of Molecular Metabolism, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden
| | - Maria Halldin
- Department of Women's and Children's Health, Akademiska University Hospital, Uppsala, Sweden
| | - Xiaoxiao Peng
- Division of Biochemistry, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden
| | - Christoph Freyer
- Division of Molecular Metabolism, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden
| | - Anna Wredenberg
- Division of Molecular Metabolism, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden
| | - Alfredo Giménez-Cassina
- Division of Biochemistry, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden
- Department of Molecular Biology, Centro de Biología Molecular "Severo Ochoa," Universidad Autónoma de Madrid, Madrid, Spain
| | - Anna Wedell
- Department of Molecular Medicine and Surgery, Science for Life Laboratory, Karolinska Institutet, Stockholm, Sweden
- Centre for Inherited Metabolic Diseases, Karolinska University Hospital, Stockholm, Sweden
| | - Elias S J Arnér
- Division of Biochemistry, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden
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Yabal M, Calleja DJ, Simpson DS, Lawlor KE. Stressing out the mitochondria: Mechanistic insights into NLRP3 inflammasome activation. J Leukoc Biol 2018; 105:377-399. [PMID: 30589456 DOI: 10.1002/jlb.mr0318-124r] [Citation(s) in RCA: 67] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2018] [Revised: 10/23/2018] [Accepted: 10/24/2018] [Indexed: 12/13/2022] Open
Abstract
Inflammasomes are multimeric protein complexes that induce the cleavage and release of bioactive IL-1β and cause a lytic form of cell death, termed pyroptosis. Due to its diverse triggers, ranging from infectious pathogens and host danger molecules to environmental irritants, the NOD-like receptor protein 3 (NLRP3) inflammasome remains the most widely studied inflammasome to date. Despite intense scrutiny, a universal mechanism for its activation remains elusive, although, recent research has focused on mitochondrial dysfunction or potassium (K+ ) efflux as key events. In this review, we give a general overview of NLRP3 inflammasome activation and explore the recently emerging noncanonical and alternative pathways to NLRP3 activation. We highlight the role of the NLRP3 inflammasome in the pathogenesis of metabolic disease that is associated with mitochondrial and oxidative stress. Finally, we interrogate the mechanisms proposed to trigger NLRP3 inflammasome assembly and activation. A greater understanding of how NLRP3 inflammasome activation is triggered may reveal new therapeutic targets for the treatment of inflammatory disease.
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Affiliation(s)
- Monica Yabal
- III. Medical Department for Hematology and Oncology, Kinikum rechts der Isar, Technische Universität München, Munich, Germany
| | - Dale J Calleja
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia
| | - Daniel S Simpson
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia.,Department of Medical Biology, University of Melbourne, Parkville, Victoria, Australia
| | - Kate E Lawlor
- Hudson Institute of Medical Research, Clayton, Victoria, Australia.,Department of Molecular and Translational Science, Monash University, Clayton, Victoria, Australia
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van Gastel J, Hendrickx JO, Leysen H, Santos-Otte P, Luttrell LM, Martin B, Maudsley S. β-Arrestin Based Receptor Signaling Paradigms: Potential Therapeutic Targets for Complex Age-Related Disorders. Front Pharmacol 2018; 9:1369. [PMID: 30546309 PMCID: PMC6280185 DOI: 10.3389/fphar.2018.01369] [Citation(s) in RCA: 61] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2018] [Accepted: 11/07/2018] [Indexed: 12/14/2022] Open
Abstract
G protein coupled receptors (GPCRs) were first characterized as signal transducers that elicit downstream effects through modulation of guanine (G) nucleotide-binding proteins. The pharmacotherapeutic exploitation of this signaling paradigm has created a drug-based field covering nearly 50% of the current pharmacopeia. Since the groundbreaking discoveries of the late 1990s to the present day, it is now clear however that GPCRs can also generate productive signaling cascades through the modulation of β-arrestin functionality. β-Arrestins were first thought to only regulate receptor desensitization and internalization - exemplified by the action of visual arrestin with respect to rhodopsin desensitization. Nearly 20 years ago, it was found that rather than controlling GPCR signal termination, productive β-arrestin dependent GPCR signaling paradigms were highly dependent on multi-protein complex formation and generated long-lasting cellular effects, in contrast to G protein signaling which is transient and functions through soluble second messenger systems. β-Arrestin signaling was then first shown to activate mitogen activated protein kinase signaling in a G protein-independent manner and eventually initiate protein transcription - thus controlling expression patterns of downstream proteins. While the possibility of developing β-arrestin biased or functionally selective ligands is now being investigated, no additional research has been performed on its possible contextual specificity in treating age-related disorders. The ability of β-arrestin-dependent signaling to control complex and multidimensional protein expression patterns makes this therapeutic strategy feasible, as treating complex age-related disorders will likely require therapeutics that can exert network-level efficacy profiles. It is our understanding that therapeutically targeting G protein-independent effectors such as β-arrestin will aid in the development of precision medicines with tailored efficacy profiles for disease/age-specific contextualities.
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Affiliation(s)
- Jaana van Gastel
- Department of Biomedical Sciences, University of Antwerp, Antwerp, Belgium.,Translational Neurobiology Group, Centre for Molecular Neuroscience, VIB, Antwerp, Belgium
| | - Jhana O Hendrickx
- Department of Biomedical Sciences, University of Antwerp, Antwerp, Belgium.,Translational Neurobiology Group, Centre for Molecular Neuroscience, VIB, Antwerp, Belgium
| | - Hanne Leysen
- Department of Biomedical Sciences, University of Antwerp, Antwerp, Belgium.,Translational Neurobiology Group, Centre for Molecular Neuroscience, VIB, Antwerp, Belgium
| | - Paula Santos-Otte
- Institute of Biophysics, Humboldt University of Berlin, Berlin, Germany
| | - Louis M Luttrell
- Division of Endocrinology, Diabetes and Medical Genetics, Medical University of South Carolina, Charleston, SC, United States
| | - Bronwen Martin
- Department of Biomedical Sciences, University of Antwerp, Antwerp, Belgium
| | - Stuart Maudsley
- Department of Biomedical Sciences, University of Antwerp, Antwerp, Belgium.,Translational Neurobiology Group, Centre for Molecular Neuroscience, VIB, Antwerp, Belgium
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Li M, Zhang Y, Cao Y, Zhang D, Liu L, Guo Y, Wang C. Icariin Ameliorates Palmitate-Induced Insulin Resistance Through Reducing Thioredoxin-Interacting Protein (TXNIP) and Suppressing ER Stress in C2C12 Myotubes. Front Pharmacol 2018; 9:1180. [PMID: 30459603 PMCID: PMC6232724 DOI: 10.3389/fphar.2018.01180] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2018] [Accepted: 09/28/2018] [Indexed: 12/23/2022] Open
Abstract
Both thioredoxin-interacting protein (TXNIP) and endoplasmic reticulum (ER) stress are implicated in skeletal muscle insulin resistance. Icariin has been found to mimic insulin action in normal skeletal muscle C2C12 cells and display anti-diabetic properties in diet-induced obese mice. However, the underlying molecular mechanism remains to be well-established. Herein, we tested the hypothesis that the protective effects of icariin on free fatty acid-induced insulin resistance were attributed to its regulation on TXNIP protein levels and ER stress in skeletal muscle cells. We found that TXNIP mediated the saturated fatty acid palmitate (PA)-induced insulin resistance in C2C12 myotubes. Icariin treatment significantly restored PA-reduced proteasome activity resulting in reduction of TXNIP protein and suppression of ER stress, as well as improvement of insulin sensitivity. Proteasome inhibition by its specific inhibitor MG132 obviously abolished the inhibitory effect of icariin on PA-induced insulin resistance. In addition, MG132 supplementation markedly abrogated the impacts of icariin on ER stress and TXNIP-mediated downstream events such as inflammation and STAT3 phosphorylation. These results clearly indicate that icariin improves PA-induced skeletal muscle insulin resistance through a proteasome-dependent mechanism, by which icariin downregulats TXNIP levels and inhibits ER stress.
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Affiliation(s)
| | | | | | | | | | | | - Changhua Wang
- Department of Pathology and Pathophysiology, Wuhan University School of Basic Medical Sciences, Wuhan, China
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Elevated Carbohydrate Response Element-Binding Protein Beta (ChREBPβ) and Thioredoxin Interacting Protein (TXNIP) Levels in Human Adipocytes Differentiated in High Glucose Concentrations. Can J Diabetes 2018; 43:215-220. [PMID: 30551936 DOI: 10.1016/j.jcjd.2018.09.009] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/14/2018] [Revised: 08/21/2018] [Accepted: 09/27/2018] [Indexed: 12/13/2022]
Abstract
OBJECTIVES Obesity and type 2 diabetes often coexist. The effect of hyperglycemia on adipose tissue is, therefore, of interest. Although studies have shown that high glucose (HG) concentrations do not inhibit adipocyte differentiation, the resulting adipocyte phenotype has not been investigated. In particular, the levels of the glucose-responsive transcription factor carbohydrate-responsive response element binding protein (ChREBP) isoforms have not been assessed. METHODS Human preadipocytes were differentiated into adipocytes in either normal glucose (NG) or HG conditions. RNA and protein analyses were used to measure the expression of ChREBP isoforms, thioredoxin interacting protein (TXNIP) and lipogenic genes. Insulin-stimulated glucose uptake was measured. RESULTS HG- vs. NG-differentiated adipocytes expressed more ChREBPβ and more TXNIP at the mRNA and protein levels. There was no change in lipogenic gene expression. HG- vs. NG-differentiated adipocytes displayed an inhibition of insulin-stimulated glucose uptake. CONCLUSIONS HG-differentiated human adipocytes have distinct molecular differences and are insulin resistant. More studies are warranted to investigate potential mechanisms linking changes in ChREBPβ and TXNIP to insulin responsiveness.
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Ras Suppresses TXNIP Expression by Restricting Ribosome Translocation. Mol Cell Biol 2018; 38:MCB.00178-18. [PMID: 30037981 DOI: 10.1128/mcb.00178-18] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2018] [Accepted: 07/16/2018] [Indexed: 12/28/2022] Open
Abstract
Oncogenic Ras upregulates aerobic glycolysis to meet the bioenergetic and biosynthetic demands of rapidly growing cells. In contrast, thioredoxin-interacting protein (TXNIP) is a potent inhibitor of glucose uptake and is frequently downregulated in human cancers. Our laboratory previously discovered that Ras activation suppresses TXNIP transcription and translation. In this study, we developed a system to study how Ras affects TXNIP translation in the absence of transcriptional effects. We show that whereas Ras drives a global increase in protein translation, it suppresses TXNIP protein synthesis by reducing the rate at which ribosomes transit the coding region of TXNIP mRNA. To investigate the underlying mechanism(s), we randomized or optimized the codons in the TXNIP message without altering the TXNIP primary amino acid sequence. Translation from these mRNA variants was still repressed by Ras, implying that mRNA secondary structure, microRNAs (miRNAs), RNA binding proteins, or codon usage does not contribute to the blockade of TXNIP synthesis. Rather, we show that the N terminus of the growing TXNIP polypeptide is the target for Ras-dependent translational repression. Our work demonstrates how Ras suppresses TXNIP translation elongation in the face of a global upregulation of protein synthesis and provides new insight into Ras-dependent metabolic reprogramming.
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40
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Mains RE, Blaby-Haas C, Rheaume BA, Eipper BA. Changes in Corticotrope Gene Expression Upon Increased Expression of Peptidylglycine α-Amidating Monooxygenase. Endocrinology 2018; 159:2621-2639. [PMID: 29788427 PMCID: PMC6287594 DOI: 10.1210/en.2018-00235] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/07/2018] [Accepted: 05/09/2018] [Indexed: 11/19/2022]
Abstract
Throughout evolution, secretion has played an essential role in the ability of organisms and single cells to survive in the face of a changing environment. Peptidylglycine α-amidating monooxygenase (PAM) is an integral membrane monooxygenase, first identified for its role in the biosynthesis of neuroendocrine peptides released by the regulated secretory pathway. PAM was subsequently identified in Chlamydomonas reinhardtii, a unicellular green alga, where it plays an essential role in constitutive secretion and in ciliogenesis. Reduced expression of C. reinhardtii PAM resulted in significant changes in secretion and ciliogenesis. Hence, a screen was performed for transcripts and proteins whose expression responded to changes in PAM levels in a mammalian corticotrope tumor cell line. The goal was to identify genes not previously known to play a role in secretion. The screen identified transcription factors, peptidyl prolyl isomerases, endosomal/lysosomal proteins, and proteins involved in tissue-specific responses to glucose and amino acid availability that had not previously been recognized as relevant to the secretory pathway. Perhaps reflecting the dependence of PAM on molecular oxygen, many PAM-responsive genes are known to be hypoxia responsive. The data highlight the extent to which the performance of the secretory pathway may be integrated into a wide diversity of signaling pathways.
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Affiliation(s)
- Richard E Mains
- Neuroscience, University of Connecticut Health Center, Farmington,
Connecticut
- Correspondence: Richard E. Mains, PhD, University of Connecticut Health Center, 263 Farmington
Avenue, Farmington, Connecticut 06030. E-mail:
| | | | - Bruce A Rheaume
- Neuroscience, University of Connecticut Health Center, Farmington,
Connecticut
| | - Betty A Eipper
- Neuroscience, University of Connecticut Health Center, Farmington,
Connecticut
- Molecular Biology & Biophysics, University of Connecticut, Farmington,
Connecticut
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Tinkov AA, Bjørklund G, Skalny AV, Holmgren A, Skalnaya MG, Chirumbolo S, Aaseth J. The role of the thioredoxin/thioredoxin reductase system in the metabolic syndrome: towards a possible prognostic marker? Cell Mol Life Sci 2018; 75:1567-1586. [PMID: 29327078 PMCID: PMC11105605 DOI: 10.1007/s00018-018-2745-8] [Citation(s) in RCA: 58] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2017] [Revised: 12/13/2017] [Accepted: 01/03/2018] [Indexed: 12/12/2022]
Abstract
Mammalian thioredoxin reductase (TrxR) is a selenoprotein with three existing isoenzymes (TrxR1, TrxR2, and TrxR3), which is found primarily intracellularly but also in extracellular fluids. The main substrate thioredoxin (Trx) is similarly found (as Trx1 and Trx2) in various intracellular compartments, in blood plasma, and is the cell's major disulfide reductase. Thioredoxin reductase is necessary as a NADPH-dependent reducing agent in biochemical reactions involving Trx. Genetic and environmental factors like selenium status influence the activity of TrxR. Research shows that the Trx/TrxR system plays a significant role in the physiology of the adipose tissue, in carbohydrate metabolism, insulin production and sensitivity, blood pressure regulation, inflammation, chemotactic activity of macrophages, and atherogenesis. Based on recent research, it has been reported that the modulation of the Trx/TrxR system may be considered as a new target in the management of the metabolic syndrome, insulin resistance, and type 2 diabetes, as well as in the treatment of hypertension and atherosclerosis. In this review evidence about a possible role of this system as a marker of the metabolic syndrome is reported.
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Affiliation(s)
- Alexey A Tinkov
- Yaroslavl State University, Yaroslavl, Russia
- Peoples' Friendship University of Russia (RUDN University), Moscow, Russia
- Institute of Cellular and Intracellular Symbiosis, Russian Academy of Sciences, Orenburg, Russia
| | - Geir Bjørklund
- Council for Nutritional and Environmental Medicine, Toften 24, 8610, Mo i Rana, Norway.
| | - Anatoly V Skalny
- Yaroslavl State University, Yaroslavl, Russia
- Peoples' Friendship University of Russia (RUDN University), Moscow, Russia
- Trace Element Institute for UNESCO, Lyon, France
- Orenburg State University, Orenburg, Russia
| | - Arne Holmgren
- Department of Medical Biochemistry and Biophysics (MBB), Karolinska Institute, Stockholm, Sweden
| | | | - Salvatore Chirumbolo
- Department of Neurological and Movement Sciences, University of Verona, Verona, Italy
| | - Jan Aaseth
- Research Department, Innlandet Hospital Trust, Brumunddal, Norway
- Inland Norway University of Applied Sciences, Elverum, Norway
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Alhawiti NM, Al Mahri S, Aziz MA, Malik SS, Mohammad S. TXNIP in Metabolic Regulation: Physiological Role and Therapeutic Outlook. Curr Drug Targets 2018; 18:1095-1103. [PMID: 28137209 PMCID: PMC5543564 DOI: 10.2174/1389450118666170130145514] [Citation(s) in RCA: 131] [Impact Index Per Article: 21.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2016] [Revised: 01/04/2017] [Accepted: 01/25/2017] [Indexed: 12/20/2022]
Abstract
Background & Objective: Thioredoxin-interacting protein (TXNIP) also known as thioredoxin binding protein-2 is a ubiquitously expressed protein that interacts and negatively regulates expression and function of Thioredoxin (TXN). Over the last few years, TXNIP has attracted considerable attention due to its wide-ranging functions impacting several aspects of energy metabolism. TXNIP acts as an important regulator of glucose and lipid metabolism through pleiotropic actions including regulation of β-cell function, hepatic glucose production, peripheral glucose uptake, adipogenesis, and substrate utilization. Overexpression of TXNIP in animal models has been shown to induce apoptosis of pancreatic β-cells, reduce insulin sensitivity in peripheral tissues like skeletal muscle and adipose, and decrease energy expenditure. On the contrary, TXNIP deficient animals are protected from diet induced insulin resistance and type 2 diabetes. Summary: Consequently, targeting TXNIP is thought to offer novel therapeutic opportunity and TXNIP inhibitors have the potential to become a powerful therapeutic tool for the treatment of diabetes mellitus. Here we summarize the current state of our understanding of TXNIP biology, highlight its role in metabolic regulation and raise critical questions that could help future research to exploit TXNIP as a therapeutic target.
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Affiliation(s)
- Naif Mohammad Alhawiti
- Experimental Medicine, King Abdullah International Medical Research Center (KAIMRC), King Saud Bin Abdulaziz University for Health Sciences (KSAU-HS), Ministry of National Guard Health Affairs (NGHA), Riyadh, Saudi Arabia
| | - Saeed Al Mahri
- Experimental Medicine, King Abdullah International Medical Research Center (KAIMRC), King Saud Bin Abdulaziz University for Health Sciences (KSAU-HS), Ministry of National Guard Health Affairs (NGHA), Riyadh, Saudi Arabia
| | - Mohammad Azhar Aziz
- Colorectal Cancer Research Program, King Abdullah International Medical Research Center (KAIMRC), King Saud Bin Abdulaziz University for Health Sciences (KSAU-HS), Ministry of National Guard Health Affairs (NGHA), Riyadh, Saudi Arabia
| | - Shuja Shafi Malik
- Experimental Medicine, King Abdullah International Medical Research Center (KAIMRC), King Saud Bin Abdulaziz University for Health Sciences (KSAU-HS), Ministry of National Guard Health Affairs (NGHA), Riyadh, Saudi Arabia
| | - Sameer Mohammad
- Experimental Medicine, King Abdullah International Medical Research Center (KAIMRC), King Saud Bin Abdulaziz University for Health Sciences (KSAU-HS), Ministry of National Guard Health Affairs (NGHA), Riyadh, Saudi Arabia
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Jo S, Chen J, Xu G, Grayson TB, Thielen LA, Shalev A. miR-204 Controls Glucagon-Like Peptide 1 Receptor Expression and Agonist Function. Diabetes 2018; 67:256-264. [PMID: 29101219 PMCID: PMC5780066 DOI: 10.2337/db17-0506] [Citation(s) in RCA: 55] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/28/2017] [Accepted: 10/30/2017] [Indexed: 12/18/2022]
Abstract
Glucagon-like peptide 1 receptor (GLP1R) agonists are widely used to treat diabetes. However, their function is dependent on adequate GLP1R expression, which is downregulated in diabetes. GLP1R is highly expressed on pancreatic β-cells, and activation by endogenous incretin or GLP1R agonists increases cAMP generation, which stimulates glucose-induced β-cell insulin secretion and helps maintain glucose homeostasis. We now have discovered that the highly β-cell-enriched microRNA, miR-204, directly targets the 3' UTR of GLP1R and thereby downregulates its expression in the β-cell-derived rat INS-1 cell line and primary mouse and human islets. Furthermore, in vivo deletion of miR-204 promoted islet GLP1R expression and enhanced responsiveness to GLP1R agonists, resulting in improved glucose tolerance, cAMP production, and insulin secretion as well as protection against diabetes. Since we recently identified thioredoxin-interacting protein (TXNIP) as an upstream regulator of miR-204, we also assessed whether in vivo deletion of TXNIP could mimic that of miR-204. Indeed, it also enhanced islet GLP1R expression and GLP1R agonist-induced insulin secretion and glucose tolerance. Thus, the present studies show for the first time that GLP1R is under the control of a microRNA, miR-204, and uncover a previously unappreciated link between TXNIP and incretin action.
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Affiliation(s)
- SeongHo Jo
- Comprehensive Diabetes Center and Department of Medicine, Division of Endocrinology, Diabetes, and Metabolism, University of Alabama at Birmingham, Birmingham, AL
| | - Junqin Chen
- Comprehensive Diabetes Center and Department of Medicine, Division of Endocrinology, Diabetes, and Metabolism, University of Alabama at Birmingham, Birmingham, AL
| | - Guanlan Xu
- Comprehensive Diabetes Center and Department of Medicine, Division of Endocrinology, Diabetes, and Metabolism, University of Alabama at Birmingham, Birmingham, AL
| | - Truman B Grayson
- Comprehensive Diabetes Center and Department of Medicine, Division of Endocrinology, Diabetes, and Metabolism, University of Alabama at Birmingham, Birmingham, AL
| | - Lance A Thielen
- Comprehensive Diabetes Center and Department of Medicine, Division of Endocrinology, Diabetes, and Metabolism, University of Alabama at Birmingham, Birmingham, AL
| | - Anath Shalev
- Comprehensive Diabetes Center and Department of Medicine, Division of Endocrinology, Diabetes, and Metabolism, University of Alabama at Birmingham, Birmingham, AL
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Koska J, Lopez L, D'Souza K, Osredkar T, Deer J, Kurtz J, Salbe AD, Harman SM, Reaven PD. Effect of liraglutide on dietary lipid-induced insulin resistance in humans. Diabetes Obes Metab 2018; 20:69-76. [PMID: 28605158 DOI: 10.1111/dom.13037] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/04/2017] [Revised: 06/01/2017] [Accepted: 06/09/2017] [Indexed: 12/11/2022]
Abstract
AIMS To test whether liraglutide suppresses postprandial elevations in lipids and thus protects against high saturated fatty acid (SFA) diet-induced insulin resistance. METHODS In a randomized placebo-controlled crossover study, 32 participants with normal or mildly impaired glucose tolerance received liraglutide and placebo for 3 weeks each. Insulin suppression tests (IST) were conducted at baseline and after a 24-hour SFA-enriched diet after each treatment. Plasma glucose, insulin, triglycerides and non-esterified fatty acids (NEFA) were measured over the initial 8 hours (breakfast and lunch) on the SFA diet. A subset of participants underwent ex vivo measurements of insulin-mediated vasodilation of adipose tissue arterioles and glucose metabolism regulatory proteins in skeletal muscle. RESULTS Liraglutide reduced plasma glucose, triglycerides and NEFA concentrations during the SFA diet (by 50%, 25% and 9%, respectively), and the SFA diet increased plasma glucose during the IST (by 36%; all P < .01 vs placebo). The SFA diet-induced impairment of vasodilation on placebo (-9.4% vs baseline; P < .01) was ameliorated by liraglutide (-4.8%; P = .1 vs baseline). In skeletal muscle, liraglutide abolished the SFA-induced increase in thioredoxin-interacting protein (TxNIP) expression (75% decrease; P < .01 vs placebo) and increased 5'AMP-activated protein kinase (AMPK) phosphorylation (50% vs -3%; P = .04 vs placebo). CONCLUSIONS Liraglutide blunted the SFA-enriched diet-induced peripheral insulin resistance. This effect may be related to improved microvascular function and modulation of TxNIP and AMPK pathways in skeletal muscle.
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Affiliation(s)
- Juraj Koska
- Phoenix VA Health Care System, Phoenix, Arizona
| | | | | | | | - James Deer
- Phoenix VA Health Care System, Phoenix, Arizona
| | - Julie Kurtz
- Phoenix VA Health Care System, Phoenix, Arizona
| | | | - Sherman M Harman
- Phoenix VA Health Care System, Phoenix, Arizona
- Kronos Longevity Research Institute, Phoenix, Arizona
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Houshmand-Oeregaard A, Hjort L, Kelstrup L, Hansen NS, Broholm C, Gillberg L, Clausen TD, Mathiesen ER, Damm P, Vaag A. DNA methylation and gene expression of TXNIP in adult offspring of women with diabetes in pregnancy. PLoS One 2017; 12:e0187038. [PMID: 29077742 PMCID: PMC5659766 DOI: 10.1371/journal.pone.0187038] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2017] [Accepted: 10/12/2017] [Indexed: 12/11/2022] Open
Abstract
BACKGROUND Fetal exposure to maternal diabetes increases the risk of type 2 diabetes (T2DM), possibly mediated by epigenetic mechanisms. Low blood TXNIP DNA methylation has been associated with elevated glucose levels and risk of T2DM, and increased skeletal muscle TXNIP gene expression was reported in subjects with impaired glucose metabolism or T2DM. Subcutaneous adipose tissue (SAT) and skeletal muscle play a key role in the control of whole body glucose metabolism and insulin action. The extent to which TXNIP DNA methylation levels are decreased and/or gene expression levels increased in SAT or skeletal muscle of a developmentally programmed at-risk population is unknown. OBJECTIVE AND METHODS The objective of this study was to investigate TXNIP DNA methylation and gene expression in SAT and skeletal muscle, and DNA methylation in blood, from adult offspring of women with gestational diabetes (O-GDM, n = 82) or type 1 diabetes (O-T1DM, n = 67) in pregnancy compared with offspring of women from the background population (O-BP, n = 57). RESULTS SAT TXNIP DNA methylation was increased (p = 0.032) and gene expression decreased (p = 0.001) in O-GDM, but these differences were attenuated after adjustment for confounders. Neither blood/muscle TXNIP DNA methylation nor muscle gene expression differed between groups. CONCLUSION We found no evidence of decreased TXNIP DNA methylation or increased gene expression in metabolic target tissues of offspring exposed to maternal diabetes. Further studies are needed to confirm and understand the paradoxical SAT TXNIP DNA methylation and gene expression changes in O-GDM subjects.
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Affiliation(s)
- Azadeh Houshmand-Oeregaard
- Center for Pregnant Women with Diabetes, Department of Obstetrics, Rigshospitalet, Copenhagen, Denmark
- Diabetes and Metabolism, Department of Endocrinology, Rigshospitalet, Copenhagen, Denmark
- Institute of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
- * E-mail:
| | - Line Hjort
- Diabetes and Metabolism, Department of Endocrinology, Rigshospitalet, Copenhagen, Denmark
- Institute of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
- Danish PhD School of Molecular Metabolism/Danish Diabetes Academy, Odense, Denmark
| | - Louise Kelstrup
- Center for Pregnant Women with Diabetes, Department of Obstetrics, Rigshospitalet, Copenhagen, Denmark
- Institute of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Ninna S. Hansen
- Diabetes and Metabolism, Department of Endocrinology, Rigshospitalet, Copenhagen, Denmark
- Institute of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
- Danish PhD School of Molecular Metabolism/Danish Diabetes Academy, Odense, Denmark
| | - Christa Broholm
- Diabetes and Metabolism, Department of Endocrinology, Rigshospitalet, Copenhagen, Denmark
| | - Linn Gillberg
- Diabetes and Metabolism, Department of Endocrinology, Rigshospitalet, Copenhagen, Denmark
| | - Tine D. Clausen
- Institute of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
- Department of Gynecology and Obstetrics, Nordsjaellands Hospital, University of Copenhagen, Hilleroed, Denmark
| | - Elisabeth R. Mathiesen
- Center for Pregnant Women with Diabetes, Department of Obstetrics, Rigshospitalet, Copenhagen, Denmark
- Institute of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
- Center for Pregnant Women with Diabetes, Department of Endocrinology, Rigshospitalet, Copenhagen, Denmark
| | - Peter Damm
- Center for Pregnant Women with Diabetes, Department of Obstetrics, Rigshospitalet, Copenhagen, Denmark
- Institute of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Allan Vaag
- Diabetes and Metabolism, Department of Endocrinology, Rigshospitalet, Copenhagen, Denmark
- Institute of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
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Kim C, Potluri P, Khalil A, Gaut D, McManus M, Compton S, Wallace DC, Yadava N. An X-chromosome linked mouse model (Ndufa1 S55A) for systemic partial Complex I deficiency for studying predisposition to neurodegeneration and other diseases. Neurochem Int 2017; 109:78-93. [PMID: 28506826 DOI: 10.1016/j.neuint.2017.05.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2017] [Revised: 04/07/2017] [Accepted: 05/08/2017] [Indexed: 01/19/2023]
Abstract
The respiratory chain Complex I deficiencies are the most common cause of mitochondrial diseases. Complex I biogenesis is controlled by 58 genes and at least 47 of these cause mitochondrial disease in humans. Two of these are X-chromosome linked nuclear (nDNA) genes (NDUFA1 and NDUFB11), and 7 are mitochondrial (mtDNA, MT-ND1-6, -4L) genes, which may be responsible for sex-dependent variation in the presentation of mitochondrial diseases. In this study, we describe an X-chromosome linked mouse model (Ndufa1S55A) for systemic partial Complex I deficiency. By homologous recombination, a point mutation T > G within 55th codon of the Ndufa1 gene was introduced. The resulting allele Ndufa1S55A introduced systemic serine-55-alanine (S55A) mutation within the MWFE protein, which is essential for Complex I assembly and stability. The S55A mutation caused systemic partial Complex I deficiency of ∼50% in both sexes. The mutant males (Ndufa1S55A/Y) displayed reduced respiratory exchange ratio (RER) and produced less body heat. They were also hypoactive and ate less. They showed age-dependent Purkinje neurons degeneration. Metabolic profiling of brain, liver and serum from males showed reduced heme levels in mutants, which correlated with altered expressions of Fech and Hmox1 mRNAs in tissues. This is the first genuine X-chromosome linked mouse model for systemic partial Complex I deficiency, which shows age-dependent neurodegeneration. The effect of Complex I deficiency on survival patterns of males vs. females was different. We believe this model will be very useful for studying sex-dependent predisposition to both spontaneous and stress-induced neurodegeneration, cancer, diabetes and other diseases.
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Affiliation(s)
- Chul Kim
- Pioneer Valley Life Sciences Institute, Springfield, MA 01199, USA
| | - Prasanth Potluri
- Center for Mitochondrial and Epigenomic Medicine at the Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Ahmed Khalil
- Pioneer Valley Life Sciences Institute, Springfield, MA 01199, USA
| | - Daria Gaut
- Center for Mitochondrial and Epigenomic Medicine at the Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Meagan McManus
- Center for Mitochondrial and Epigenomic Medicine at the Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Shannon Compton
- Pioneer Valley Life Sciences Institute, Springfield, MA 01199, USA
| | - Douglas C Wallace
- Center for Mitochondrial and Epigenomic Medicine at the Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Nagendra Yadava
- Pioneer Valley Life Sciences Institute, Springfield, MA 01199, USA; Division of Endocrinology, Diabetes & Metabolism at Baystate Medical Center, Tufts University School of Medicine, Springfield, MA 01199, USA.
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Deletion of TXNIP Mitigates High-Fat Diet-Impaired Angiogenesis and Prevents Inflammation in a Mouse Model of Critical Limb Ischemia. Antioxidants (Basel) 2017; 6:antiox6030047. [PMID: 28661427 PMCID: PMC5618075 DOI: 10.3390/antiox6030047] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2017] [Revised: 05/25/2017] [Accepted: 06/23/2017] [Indexed: 12/21/2022] Open
Abstract
Background: Previous work demonstrated that high-fat diet (HFD) triggered thioredoxin-interacting protein (TXNIP) and that silencing TXNIP prevents diabetes-impaired vascular recovery. Here, we examine the impact of genetic deletion of TXNIP on HFD-impaired vascular recovery using hind limb ischemia model. Methods: Wild type mice (WT, C57Bl/6) and TXNIP knockout mice (TKO) were fed either normal chow diet (WT-ND and TKO-ND) or 60% high-fat diet (WT-HFD and TKO-HFD). After four weeks of HFD, unilateral hind limb ischemia was performed and blood flow was measured using Laser doppler scanner at baseline and then weekly for an additional three weeks. Vascular density, nitrative stress, infiltration of CD68+ macrophages, and expression of inflammasome, vascular endothelial growth factor (VEGF), VEGF receptor-2 were examined by slot blot, Western blot and immunohistochemistry. Results: By week 8, HFD caused similar increases in weight, cholesterol and triglycerides in both WT and TKO. At week 4 and week 8, HFD significantly impaired glucose tolerance in WT and to a lesser extent in TKO. HFD significantly impaired blood flow and vascular density (CD31 labeled) in skeletal muscle of WT mice compared to ND but not in TKO. HFD and ischemia significantly induced tyrosine nitration, and systemic IL-1β and infiltration of CD68+ cells in skeletal muscle from WT but not from TKO. HFD significantly increased cleaved-caspase-1 and IL-1 β compared to ND. Under both ND, ischemia tended to increase VEGF expression and increased VEGFR2 activation in WT only but not TKO. Conclusion: Similar to prior observation in diabetes, HFD-induced obesity can compromise vascular recovery in response to ischemic insult. The mechanism involves increased TXNIP-NLRP3 (nucleotide-binding oligomerization domain-like receptor protein 3) inflammasome activation, nitrative stress and impaired VEGFR2 activation. Deletion of TXNIP restored blood flow, reduced nitrative stress and blunted inflammasome-mediated inflammation; however, it did not impact VEGF/VEGFR2 in HFD. Targeting TXNIP-NLRP3 inflammasome can provide potential therapeutic target in obesity-induced vascular complication.
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ASK1 (MAP3K5) is transcriptionally upregulated by E2F1 in adipose tissue in obesity, molecularly defining a human dys-metabolic obese phenotype. Mol Metab 2017; 6:725-736. [PMID: 28702328 PMCID: PMC5485239 DOI: 10.1016/j.molmet.2017.05.003] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/15/2017] [Accepted: 03/27/2017] [Indexed: 02/06/2023] Open
Abstract
Objective Obesity variably disrupts human health, but molecular-based patients' health-risk stratification is limited. Adipose tissue (AT) stresses may link obesity with metabolic dysfunction, but how they signal in humans remains poorly-characterized. We hypothesized that a transcriptional AT stress-signaling cascade involving E2F1 and ASK1 (MAP3K5) molecularly defines high-risk obese subtype. Methods ASK1 expression in human AT biopsies was determined by real-time PCR analysis, and chromatin immunoprecipitation (ChIP) adopted to AT explants was used to evaluate the binding of E2F1 to the ASK1 promoter. Dual luciferase assay was used to measure ASK1 promoter activity in HEK293 cells. Effects of E2F1 knockout/knockdown in adipocytes was assessed utilizing mouse-embryonal-fibroblasts (MEF)-derived adipocyte-like cells from WT and E2F1−/− mice and by siRNA, respectively. ASK1 depletion in adipocytes was studied in MEF-derived adipocyte-like cells from WT and adipose tissue-specific ASK1 knockout mice (ASK1-ATKO). Results Human visceral-AT ASK1 mRNA (N = 436) was associated with parameters of obesity-related cardio-metabolic morbidity. Adjustment for E2F1 expression attenuated the association of ASK1 with fasting glucose, insulin resistance, circulating IL-6, and lipids (triglycerides, HDL-cholesterol), even after adjusting for BMI. Chromatin-immunoprecipitation in human-AT explants revealed BMI-associated increased occupancy of the ASK1 promoter by E2F1 (r2 = 0.847, p < 0.01). In adipocytes, siRNA-mediated E2F1-knockdown, and MEF-derived adipocytes of E2F1-knockout mice, demonstrated decreased ASK1 expression and signaling to JNK. Mutation/truncation of an E2F1 binding site in hASK1 promoter decreased E2F1-induced ASK1 promoter activity, whereas E2F1-mediated sensitization of ASK1 promoter to further activation by TNFα was inhibited by JNK-inhibitor. Finally, MEF-derived adipocytes from adipocyte-specific ASK1-knockout mice exhibited lower leptin and higher adiponectin expression and secretion, and resistance to the effects of TNFα. Conclusions AT E2F1 –ASK1 molecularly defines a metabolically-detrimental obese sub-phenotype. Functionally, it may negatively affect AT endocrine function, linking AT stress to whole-body metabolic dysfunction.
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Liu CY, Hao YN, Yin F, Zhang YL, Liu JH. Geniposide accelerates proteasome degradation of Txnip to inhibit insulin secretion in pancreatic β-cells. J Endocrinol Invest 2017; 40:505-512. [PMID: 28000177 DOI: 10.1007/s40618-016-0591-9] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/04/2016] [Accepted: 11/27/2016] [Indexed: 01/17/2023]
Abstract
PURPOSE To analyze the role of geniposide in the protein degradation of Txnip and to determine the impact of Txnip on geniposide-regulated GSIS in pancreatic INS-1 cells. METHODS The content of Txnip protein was measured by western blot; insulin content and glucose uptake were determined by ELISA; and knockdown of Txnip was the method of RNA interference. RESULTS Glucose induces a rapid increase in Txnip protein, and geniposide accelerates the degradation of Txnip via proteasome pathway in the presence of high glucose (25 mM) in INS-1 pancreatic β-cells. And MG132, a proteasomal inhibitor, potentiates glucose uptake, metabolism (ATP production) and glucose-stimulated insulin secretion (GSIS) in high-glucose (25 mM)-treated INS-1 cells, but geniposide significantly prevents these effects. Furthermore, the combination of geniposide and Txnip knockdown shows substantial synergistic effects to reduce glucose uptake, metabolism and GSIS in high-glucose (25 mM)-treated INS-1 cells. CONCLUSIONS Txnip protein played an essential role in glucose uptake, metabolism and GSIS, and geniposide could accelerate the degradation via proteasome pathway in high-glucose-treated pancreatic INS-1 cells.
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Affiliation(s)
- C Y Liu
- Chongqing Key Lab of Medicinal Chemistry & Molecular Pharmacology, Chongqing University of Technology, Chongqing, 400054, China
| | - Y N Hao
- Chongqing Key Lab of Medicinal Chemistry & Molecular Pharmacology, Chongqing University of Technology, Chongqing, 400054, China
| | - F Yin
- Chongqing Key Lab of Medicinal Chemistry & Molecular Pharmacology, Chongqing University of Technology, Chongqing, 400054, China.
| | - Y L Zhang
- Chongqing Key Lab of Medicinal Chemistry & Molecular Pharmacology, Chongqing University of Technology, Chongqing, 400054, China
| | - J H Liu
- Chongqing Key Lab of Medicinal Chemistry & Molecular Pharmacology, Chongqing University of Technology, Chongqing, 400054, China.
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