1
|
CHIP Haploinsufficiency Exacerbates Hepatic Steatosis via Enhanced TXNIP Expression and Endoplasmic Reticulum Stress Responses. Antioxidants (Basel) 2023; 12:antiox12020458. [PMID: 36830016 PMCID: PMC9951908 DOI: 10.3390/antiox12020458] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2023] [Revised: 02/04/2023] [Accepted: 02/09/2023] [Indexed: 02/17/2023] Open
Abstract
TXNIP is a critical regulator of glucose homeostasis, fatty acid synthesis, and cholesterol accumulation in the liver, and it has been reported that metabolic diseases, such as obesity, atherosclerosis, hyperlipidemia, type 2 diabetes, and nonalcoholic fatty liver disease (NAFLD), are associated with endoplasmic reticulum (ER) stress. Because CHIP, an E3 ligase, was known to be involved in regulating tissue injury and inflammation in liver, its role in regulating ER stress-induced NAFLD was investigated in two experimental NAFLD models, a tunicamycin (TM)-induced and other diet-induced NAFLD mice models. In the TM-induced NAFLD model, intraperitoneal injection of TM induced liver steatosis in both CHIP+/+ and CHIP+/- mice, but it was severely exacerbated in CHIP+/- mice compared to CHIP+/+ mice. Key regulators of ER stress and de novo lipogenesis were also enhanced in the livers of TM-inoculated CHIP+/- mice. Furthermore, in the diet-induced NAFLD models, CHIP+/- mice developed severely impaired glucose tolerance, insulin resistance and hepatic steatosis compared to CHIP+/+ mice. Interestingly, CHIP promoted ubiquitin-dependent degradation of TXNIP in vitro, and inhibition of TXNIP was further found to alleviate the inflammation and ER stress responses increased by CHIP inhibition. In addition, the expression of TXNIP was increased in mice deficient in CHIP in the TM- and diet-induced models. These findings suggest that CHIP modulates ER stress and inflammatory responses by inhibiting TXNIP, and that CHIP protects against TM- or HF-HS diet-induced NAFLD and serves as a potential therapeutic means for treating liver diseases.
Collapse
|
2
|
He Q, Chen B, Wang G, Zhou D, Zeng H, Li X, Song Y, Yu X, Liang W, Chen H, Liu X, Wu Q, Wu L, Zhang L, Li H, Hu X, Zhou W. Co-Crystal of Rosiglitazone With Berberine Ameliorates Hyperglycemia and Insulin Resistance Through the PI3K/AKT/TXNIP Pathway In Vivo and In Vitro. Front Pharmacol 2022; 13:842879. [PMID: 35571083 PMCID: PMC9096649 DOI: 10.3389/fphar.2022.842879] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2021] [Accepted: 04/14/2022] [Indexed: 11/13/2022] Open
Abstract
Background: Type 2 diabetes mellitus (T2DM) is a chronic metabolic disease characterized by insulin resistance and hyperglycemia. This study examined the effect and elucidated the mechanism of improvement of hyperglycemia and insulin resistance by a co-crystal of rosiglitazone with berberine (RB) in high-sugar high-fat diet (HSHFD)-induced diabetic KKAy mice. Methods: Diabetic KKAy mice were randomly divided into seven groups: KKAy model control group (DM control) treated with 3% sodium carboxymethyl cellulose; RB groups, administered daily with RB 0.7 mg/kg (RB-L), 2.11 mg/kg (RB-M), or 6.33 mg/kg (RB-H); positive control groups, administered daily with rosiglitazone 1.04 mg/kg (RSG), berberine 195 mg/kg (BBR), or combination of 1.04 mg/kg RSG and 1.08 mg/kg BBR (MIX). Test compounds were administered orally for 8 weeks. Non-diabetic C57BL/6J mice were used as normal control (NC). Blood glucose, food intake, body weight, glucose-lipid metabolism, and pathological changes in the pancreas and liver were examined. We further evaluated the mechanism of action of RB in C2C12 and HepG2 cells stimulated with high glucose and palmitate. Results: RB treatment improved glucolipid metabolism and insulin resistance in diabetic KKAy mice. RB reduced blood glucose levels, white fat index, plasma triglyceride (TG), low-density lipoprotein (LDL), gastric inhibitory peptide (GIP), and insulin levels, increased the levels of plasma glucagon-like peptide-1 (GLP-1), high-density lipoprotein (HDL), and glycogen content in the liver and muscle; and improved oral glucose tolerance test (OGTT), insulin tolerance test (ITT), and pathological changes in the pancreas and liver of KKAy mice. Moreover, RB upregulated p-PI3K and p-AKT levels and reduced TXNIP expression in KKAy mice and in HepG2 and C2C12 cells. Conclusion: These data indicate that RB ameliorates insulin resistance and metabolic disorders, and the mechanism might be through regulating the PI3K/AKT/TXNIP signaling pathway . Thus, the co-crystal drug RB may be considered as a potential antidiabetic agent for future clinical therapy.
Collapse
Affiliation(s)
- Qichen He
- Department of Pharmacology, College of Pharmacy, Chongqing Medical University, Chongqing, China.,Chongqing Key Laboratory of Drug Metabolism, Chongqing Medical University, Chongqing, China.,Key Laboratory for Biochemistry and Molecular Pharmacology of Chongqing, Chongqing Medical University, Chongqing, China
| | - Bo Chen
- Department of Pharmacology, College of Pharmacy, Chongqing Medical University, Chongqing, China.,Chongqing Key Laboratory of Drug Metabolism, Chongqing Medical University, Chongqing, China.,Key Laboratory for Biochemistry and Molecular Pharmacology of Chongqing, 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 Medical University, Chongqing, China.,Key Laboratory for Biochemistry and Molecular Pharmacology of Chongqing, Chongqing Medical University, Chongqing, China
| | - Duanfang Zhou
- Department of Pharmacology, College of Pharmacy, Chongqing Medical University, Chongqing, China.,Chongqing Key Laboratory of Drug Metabolism, Chongqing Medical University, Chongqing, China.,Key Laboratory for Biochemistry and Molecular Pharmacology of Chongqing, Chongqing Medical University, Chongqing, China
| | - Hongfang Zeng
- Department of Pharmacology, College of Pharmacy, Chongqing Medical University, Chongqing, China.,Chongqing Key Laboratory of Drug Metabolism, Chongqing Medical University, Chongqing, China.,Key Laboratory for Biochemistry and Molecular Pharmacology of Chongqing, 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 Medical University, Chongqing, China.,Key Laboratory for Biochemistry and Molecular Pharmacology of Chongqing, Chongqing Medical University, Chongqing, China
| | - Yi Song
- Department of Pharmacology, College of Pharmacy, Chongqing Medical University, Chongqing, China.,Chongqing Key Laboratory of Drug Metabolism, Chongqing Medical University, Chongqing, China.,Key Laboratory for Biochemistry and Molecular Pharmacology of Chongqing, Chongqing Medical University, Chongqing, China
| | - Xiaoping Yu
- Department of Pharmacology, College of Pharmacy, Chongqing Medical University, Chongqing, China.,Chongqing Key Laboratory of Drug Metabolism, Chongqing Medical University, Chongqing, China.,Key Laboratory for Biochemistry and Molecular Pharmacology of Chongqing, Chongqing Medical University, Chongqing, China
| | - Wenxin Liang
- Department of Pharmacology, College of Pharmacy, Chongqing Medical University, Chongqing, China.,Chongqing Key Laboratory of Drug Metabolism, Chongqing Medical University, Chongqing, China.,Key Laboratory for Biochemistry and Molecular Pharmacology of Chongqing, Chongqing Medical University, Chongqing, China
| | - Huiling Chen
- Department of Pharmacology, College of Pharmacy, Chongqing Medical University, Chongqing, China.,Chongqing Key Laboratory of Drug Metabolism, Chongqing Medical University, Chongqing, China.,Key Laboratory for Biochemistry and Molecular Pharmacology of Chongqing, Chongqing Medical University, Chongqing, China
| | - Xu Liu
- Department of Pharmacology, College of Pharmacy, Chongqing Medical University, Chongqing, China.,Chongqing Key Laboratory of Drug Metabolism, Chongqing Medical University, Chongqing, China.,Key Laboratory for Biochemistry and Molecular Pharmacology of Chongqing, Chongqing Medical University, Chongqing, China
| | - Qiuya Wu
- Department of Pharmacology, College of Pharmacy, Chongqing Medical University, Chongqing, China.,Chongqing Key Laboratory of Drug Metabolism, Chongqing Medical University, Chongqing, China.,Key Laboratory for Biochemistry and Molecular Pharmacology of Chongqing, Chongqing Medical University, Chongqing, China
| | - Lihong Wu
- Department of Pharmacology, College of Pharmacy, Chongqing Medical University, Chongqing, China.,Chongqing Key Laboratory of Drug Metabolism, Chongqing Medical University, Chongqing, China.,Key Laboratory for Biochemistry and Molecular Pharmacology of Chongqing, Chongqing Medical University, Chongqing, China
| | - Limei Zhang
- Department of Pharmacology, College of Pharmacy, Chongqing Medical University, Chongqing, China.,Chongqing Key Laboratory of Drug Metabolism, Chongqing Medical University, Chongqing, China.,Key Laboratory for Biochemistry and Molecular Pharmacology of Chongqing, Chongqing Medical University, Chongqing, China
| | - Huizhen Li
- Department of Pharmacology, College of Pharmacy, Chongqing Medical University, Chongqing, China
| | - Xiangnan Hu
- Department of Pharmacology, College of Pharmacy, Chongqing Medical University, Chongqing, China.,Department of Medicinal Chemistry, College of Pharmacy, Chongqing Medical University, Chongqing, China
| | - Weiying Zhou
- Department of Pharmacology, College of Pharmacy, Chongqing Medical University, Chongqing, China.,Chongqing Key Laboratory of Drug Metabolism, Chongqing Medical University, Chongqing, China.,Key Laboratory for Biochemistry and Molecular Pharmacology of Chongqing, Chongqing Medical University, Chongqing, China
| |
Collapse
|
3
|
Localization of Thioredoxin-Interacting Protein in Aging and Alzheimer’s Disease Brains. NEUROSCI 2022. [DOI: 10.3390/neurosci3020013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Thioredoxin-Interacting Protein (TXNIP) has been shown to have significant pathogenic roles in many human diseases, particularly those associated with diabetes and hyperglycemia. Its main mode of action is to sequester thioredoxins, resulting in enhanced oxidative stress. The aim of this study was to identify if cellular expression of TXNIP in human aged and Alzheimer’s disease (AD) brains correlated with pathological structures. This study employed fixed tissue sections and protein extracts of temporal cortex from AD and aged control brains. Studies employed light and fluorescent immunohistochemical techniques using the monoclonal antibody JY2 to TXNIP to identify cellular structures. Immunoblots were used to quantify relative amounts of TXNIP in brain protein extracts. The major finding was the identification of TXNIP immunoreactivity in selective neuronal populations and structures, particularly in non-AD brains. In AD brains, less neuronal TXNIP but increased numbers of TXNIP-positive plaque-associated microglia were observed. Immunoblot analyses showed no significant increase in levels of TXNIP protein in the AD samples tested. In conclusion, this study identified altered patterns of expression of TXNIP in human brains with progression of AD pathology.
Collapse
|
4
|
Nasoohi S, Parveen K, Ishrat T. Metabolic Syndrome, Brain Insulin Resistance, and Alzheimer's Disease: Thioredoxin Interacting Protein (TXNIP) and Inflammasome as Core Amplifiers. J Alzheimers Dis 2019; 66:857-885. [PMID: 30372683 DOI: 10.3233/jad-180735] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Empirical evidence indicates a strong association between insulin resistance and pathological alterations related to Alzheimer's disease (AD) in different cerebral regions. While cerebral insulin resistance is not essentially parallel with systemic metabolic derangements, type 2 diabetes mellitus (T2DM) has been established as a risk factor for AD. The circulating "toxic metabolites" emerging in metabolic syndrome may engage several biochemical pathways to promote oxidative stress and neuroinflammation leading to impair insulin function in the brain or "type 3 diabetes". Thioredoxin-interacting protein (TXNIP) as an intracellular amplifier of oxidative stress and inflammasome activation may presumably mediate central insulin resistance. Emerging data including those from our recent studies has demonstrated a sharp TXNIP upregulation in stroke, aging and AD and well underlining the significance of this hypothesis. With the main interest to illustrate TXNIP place in type 3 diabetes, the present review primarily briefs the potential mechanisms contributing to cerebral insulin resistance in a metabolically deranged environment. Then with a particular focus on plausible TXNIP functions to drive and associate with AD pathology, we present the most recent evidence supporting TXNIP as a promising therapeutic target in AD as an age-associated dementia.
Collapse
|
5
|
Filhoulaud G, Benhamed F, Pagesy P, Bonner C, Fardini Y, Ilias A, Movassat J, Burnol AF, Guilmeau S, Kerr-Conte J, Pattou F, Issad T, Postic C. O-GlcNacylation Links TxNIP to Inflammasome Activation in Pancreatic β Cells. Front Endocrinol (Lausanne) 2019; 10:291. [PMID: 31164864 PMCID: PMC6536593 DOI: 10.3389/fendo.2019.00291] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/30/2019] [Accepted: 04/23/2019] [Indexed: 01/30/2023] Open
Abstract
Thioredoxin interacting protein (TxNIP), which strongly responds to glucose, has emerged as a central mediator of glucotoxicity in pancreatic β cells. TxNIP is a scaffold protein interacting with target proteins to inhibit or stimulate their activity. Recent studies reported that high glucose stimulates the interaction of TxNIP with the inflammasome protein NLRP3 (NLR family, pyrin domain containing 3) to increase interleukin-1 β (IL1β) secretion by pancreatic β cells. To better understand the regulation of TxNIP by glucose in pancreatic β cells, we investigated the implication of O-linked β-N-acetylglucosamine (O-GlcNAcylation) in regulating TxNIP at the posttranslational level. O-GlcNAcylation of proteins is controlled by two enzymes: the O-GlcNAc transferase (OGT), which transfers a monosaccharide to serine/threonine residues on target proteins, and the O-GlcNAcase (OGA), which removes it. Our study shows that TxNIP is subjected to O-GlcNAcylation in response to high glucose concentrations in β cell lines. Modification of the O-GlcNAcylation pathway through manipulation of OGT or OGA expression or activity significantly modulates TxNIP O-GlcNAcylation in INS1 832/13 cells. Interestingly, expression and O-GlcNAcylation of TxNIP appeared to be increased in islets of diabetic rodents. At the mechanistic level, the induction of the O-GlcNAcylation pathway in human and rat islets promotes inflammasome activation as evidenced by enhanced cleaved IL1β. Overexpression of OGT in HEK293 or INS1 832/13 cells stimulates TxNIP and NLRP3 interaction, while reducing TxNIP O-GlcNAcylation through OGA overexpression destabilizes this interaction. Altogether, our study reveals that O-GlcNAcylation represents an important regulatory mechanism for TxNIP activity in β cells.
Collapse
Affiliation(s)
- Gaelle Filhoulaud
- INSERM U1016, Institut Cochin, Paris, France
- CNRS UMR 8104, Paris, France
- Université Paris Descartes, Sorbonne Paris Cité, Paris, France
| | - Fadila Benhamed
- INSERM U1016, Institut Cochin, Paris, France
- CNRS UMR 8104, Paris, France
- Université Paris Descartes, Sorbonne Paris Cité, Paris, France
| | - Patrick Pagesy
- INSERM U1016, Institut Cochin, Paris, France
- CNRS UMR 8104, Paris, France
- Université Paris Descartes, Sorbonne Paris Cité, Paris, France
| | - Caroline Bonner
- Pasteur Institute de Lille, Lille, France
- INSERM U1190 - EGID, Lille, France
| | - Yann Fardini
- INSERM U1016, Institut Cochin, Paris, France
- CNRS UMR 8104, Paris, France
- Université Paris Descartes, Sorbonne Paris Cité, Paris, France
| | - Anissa Ilias
- UMR8251-CNRS, Paris, France
- Université Paris Diderot, Sorbonne Paris Cité, Paris, France
| | - Jamileh Movassat
- UMR8251-CNRS, Paris, France
- Université Paris Diderot, Sorbonne Paris Cité, Paris, France
| | - Anne-Françoise Burnol
- INSERM U1016, Institut Cochin, Paris, France
- CNRS UMR 8104, Paris, France
- Université Paris Descartes, Sorbonne Paris Cité, Paris, France
| | - Sandra Guilmeau
- INSERM U1016, Institut Cochin, Paris, France
- CNRS UMR 8104, Paris, France
- Université Paris Descartes, Sorbonne Paris Cité, Paris, France
| | | | | | - Tarik Issad
- INSERM U1016, Institut Cochin, Paris, France
- CNRS UMR 8104, Paris, France
- Université Paris Descartes, Sorbonne Paris Cité, Paris, France
| | - Catherine Postic
- INSERM U1016, Institut Cochin, Paris, France
- CNRS UMR 8104, Paris, France
- Université Paris Descartes, Sorbonne Paris Cité, Paris, France
- *Correspondence: Catherine Postic
| |
Collapse
|
6
|
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.
Collapse
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
| |
Collapse
|
7
|
Serum Vitamin D and Its Upregulated Protein, Thioredoxin Interacting Protein, Are Associated With Beta-Cell Dysfunction in Adult Patients With Type 1 and Type 2 Diabetes. Can J Diabetes 2018; 42:588-594. [PMID: 29980378 DOI: 10.1016/j.jcjd.2018.02.012] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/07/2016] [Accepted: 02/26/2018] [Indexed: 01/12/2023]
Abstract
OBJECTIVES Diabetes mellitus is characterized by either complete deficiency of insulin secretion, as in type 1 diabetes, or decompensation of the pancreatic beta cells in type 2 diabetes. Both vitamin D (vitD) and thioredoxin interacting protein (TXNIP) have been shown to be involved in beta-cell dysfunction. Therefore, this study was designed to examine vitD and TXNIP serum levels in patients with diabetes and to correlate these levels with beta-cell function markers in both types of diabetes. METHODS The routine biochemical parameters and the serum levels of vitD and TXNIP were measured in 20 patients with type 1 diabetes and 20 patients with type 2 diabetes. The levels were then compared to those of 15 healthy control volunteers. Insulin, C-peptide and proinsulin (PI), vitD and TXNIP were measured by ELISA. Beta-cell dysfunction was assessed by homeostatic model assessment (HOMA-beta), proinsulin-to-C-peptide (PI/C) and proinsulin-to-insulin (PI/I) ratios. Correlations among various parameters were studied. RESULTS Patients with type 1 diabetes had significantly lower HOMA-beta, vitD and TXNIP levels; however, they had higher PI/C levels than the control group. Meanwhile, patients with type 2 diabetes had significantly higher C-peptide, proinsulin, PI/C, HOMA-insulin resistance (HOMA-IR) and lower HOMA-beta and vitD levels, with no significant difference in TXNIP levels as compared to the control group. In addition, vitD was significantly correlated positively with HOMA-beta and TXNIP and negatively with PI, PI/C, PI/I and HOMA-IR. TXNIP correlated positively with HOMA-beta and negatively with PI/C. CONCLUSIONS Our data showed that vitD and TXNIP were associated with different beta-cell dysfunction markers, indicating their potential abilities to predict the beta-cell status in people with diabetes.
Collapse
|
8
|
Talaia G, Gournas C, Saliba E, Barata-Antunes C, Casal M, André B, Diallinas G, Paiva S. The α-Arrestin Bul1p Mediates Lactate Transporter Endocytosis in Response to Alkalinization and Distinct Physiological Signals. J Mol Biol 2017; 429:3678-3695. [PMID: 28965784 DOI: 10.1016/j.jmb.2017.09.014] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2017] [Revised: 09/21/2017] [Accepted: 09/22/2017] [Indexed: 01/06/2023]
Abstract
Eukaryotic α-arrestins connect environmental or stress signaling pathways to the endocytosis of plasma membrane transporters or receptors. The Saccharomyces cerevisiae lactate transporter Jen1p has been used as a model cargo for elucidating the mechanisms underlying endocytic turnover in response to carbon sources. Here, we discover a novel pathway of Jen1p endocytosis mediated by the α-arrestin Bul1p in response to the presence of cycloheximide or rapamycin, or prolonged growth in lactate. While cycloheximide or rapamycin modify cells pleiotropically, the major effect of prolonged growth in lactate was shown to be external pH alkalinization. Importantly, employment of specific inactive Jen1p versions showed that Bul1p-dependent endocytosis requires lactate transport, according to the signal imposed. Our results support a model where conformational changes of Jen1p, associated with substrate/H+ symport, are critical for the efficiency of Bul1p-dependent Jen1p turnover.
Collapse
Affiliation(s)
- Gabriel Talaia
- Centre of Molecular and Environmental Biology, Department of Biology, University of Minho, Campus of Gualtar, Braga 4710-057, Portugal
| | - Christos Gournas
- Molecular Physiology of the Cell, Université Libre de Bruxelles (ULB), IBMM, Gosselies, Belgium
| | - Elie Saliba
- Molecular Physiology of the Cell, Université Libre de Bruxelles (ULB), IBMM, Gosselies, Belgium
| | - Cláudia Barata-Antunes
- Centre of Molecular and Environmental Biology, Department of Biology, University of Minho, Campus of Gualtar, Braga 4710-057, Portugal
| | - Margarida Casal
- Centre of Molecular and Environmental Biology, Department of Biology, University of Minho, Campus of Gualtar, Braga 4710-057, Portugal
| | - Bruno André
- Molecular Physiology of the Cell, Université Libre de Bruxelles (ULB), IBMM, Gosselies, Belgium
| | - George Diallinas
- Department of Biology, National and Kapodistrian University of Athens, Panepistimioupolis 15784, Athens, Greece
| | - Sandra Paiva
- Centre of Molecular and Environmental Biology, Department of Biology, University of Minho, Campus of Gualtar, Braga 4710-057, Portugal.
| |
Collapse
|
9
|
Chong CR, Chan WPA, Nguyen TH, Liu S, Procter NEK, Ngo DT, Sverdlov AL, Chirkov YY, Horowitz JD. Thioredoxin-interacting protein: pathophysiology and emerging pharmacotherapeutics in cardiovascular disease and diabetes. Cardiovasc Drugs Ther 2015; 28:347-60. [PMID: 25088927 DOI: 10.1007/s10557-014-6538-5] [Citation(s) in RCA: 64] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
The thioredoxin system, which consists of thioredoxin (Trx), nicotinamide adenine dinucleotide phosphate (NADPH) and thioredoxin reductase (TrxR), has emerged as a major anti-oxidant involved in the maintenance of cellular physiology and survival. Dysregulation in this system has been associated with metabolic, cardiovascular, and malignant disorders. Thioredoxin-interacting protein (TXNIP), also known as vitamin D-upregulated protein or thioredoxin-binding-protein-2, functions as a physiological inhibitor of Trx, and pathological suppression of Trx by TXNIP has been demonstrated in diabetes and cardiovascular diseases. Furthermore, TXNIP effects are partially Trx-independent; these include direct activation of inflammation and inhibition of glucose uptake. Many of the effects of TXNIP are initiated by its dissociation from intra-nuclear binding with Trx or other SH-containing proteins: these effects include its migration to cytoplasm, modulating stress responses in mitochondria and endoplasmic reticulum, and also potentially activating apoptotic pathways. TXNIP also interacts with the nitric oxide (NO) signaling system, with apparent suppression of NO effect. TXNIP production is modulated by redox stress, glucose levels, hypoxia and several inflammatory activators. In recent studies, it has been shown that therapeutic agents including insulin, metformin, angiotensin converting enzyme inhibitors and calcium channel blockers reduce TXNIP expression, although it is uncertain to what extent TXNIP suppression contributes to their clinical efficacy. This review addresses the role of TXNIP in health and in cardiovascular and metabolic disorders. Finally, the potential advantages (and disadvantages) of pharmacological suppression of TXNIP in cardiovascular disease and diabetes are summarized.
Collapse
Affiliation(s)
- Cher-Rin Chong
- Cardiology and Clinical Pharmacology Department, Basil Hetzel Institute, Queen Elizabeth Hospital, University of Adelaide, Adelaide, Australia
| | | | | | | | | | | | | | | | | |
Collapse
|
10
|
Shalev A. Minireview: Thioredoxin-interacting protein: regulation and function in the pancreatic β-cell. Mol Endocrinol 2014; 28:1211-20. [PMID: 24911120 DOI: 10.1210/me.2014-1095] [Citation(s) in RCA: 133] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Pancreatic β-cells are responsible for insulin production, and loss of functional β-cell mass is now recognized as a critical step in the pathogenesis of both type 1 and type 2 diabetes. However, the factors controlling the life and death of the pancreatic β-cell have only started to be elucidated. Discovered as the top glucose-induced gene in a human islet microarray study 12 years ago, thioredoxin-interacting protein (TXNIP) has now emerged as such a key player in pancreatic β-cell biology. Since then, β-cell expression of TXNIP has been found to be tightly regulated by multiple factors and to be dramatically increased in diabetic islets. Elevated TXNIP levels induce β-cell apoptosis, whereas TXNIP deficiency protects against type 1 and type 2 diabetes by promoting β-cell survival. TXNIP interacts with and inhibits thioredoxin and thereby controls the cellular redox state, but it also belongs to the α-arrestin family of proteins and regulates a variety of metabolic processes. Most recently, TXNIP has been discovered to control β-cell microRNA expression, β-cell function, and insulin production. In this review, the current state of knowledge regarding regulation and function of TXNIP in the pancreatic β-cell and the implications for drug development are discussed.
Collapse
Affiliation(s)
- Anath Shalev
- Comprehensive Diabetes Center and Department of Medicine, Division of Endocrinology, Diabetes and Metabolism, University of Alabama at Birmingham, Birmingham, Alabama 35294
| |
Collapse
|
11
|
Lee MH, Jeon HM, Han JH, Park N, Kang C, Sessler JL, Kim JS. Toward a chemical marker for inflammatory disease: a fluorescent probe for membrane-localized thioredoxin. J Am Chem Soc 2014; 136:8430-7. [PMID: 24840911 PMCID: PMC4227802 DOI: 10.1021/ja503356q] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
![]()
Thioredoxin
(Trx) is a redox-active protein that plays a key role
in mitigating the effects of oxidative stress. The secretion of Trx
on the plasma membrane has been suggested as a distinctive feature
of inflammation. However, selective monitoring of membrane-associated
Trx activity has proved challenging because of the ubiquity of Trx
action in cells. Here, we report a Trx-specific probe that allows
visualization of Trx activity associated with the membranes via fluorescence
microscopy. The ability of this probe to act as a possible screening
tool for agents that modulate Trx secretion was demonstrated in HeLa
cells under oxidative stress conditions and in a cellular hepatosteatosis
model. Control experiments serve to confirm that the response seen
for the present probe is due to Trx and that it is selective over
various potentially competing metabolites, including thiol-containing
small molecules and test proteins.
Collapse
Affiliation(s)
- Min Hee Lee
- Department of Chemistry, The University of Texas at Austin , Austin, Texas 78712-1224, United States
| | | | | | | | | | | | | |
Collapse
|
12
|
Sverdlov AL, Chan WPA, Procter NEK, Chirkov YY, Ngo DTM, Horowitz JD. Reciprocal regulation of NO signaling and TXNIP expression in humans: impact of aging and ramipril therapy. Int J Cardiol 2013; 168:4624-30. [PMID: 23958415 DOI: 10.1016/j.ijcard.2013.07.159] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/14/2013] [Accepted: 07/19/2013] [Indexed: 12/26/2022]
Abstract
BACKGROUND Impaired tissue responsiveness to nitric oxide (NO) occurs in many cardiovascular diseases as well as with advanced age and is a correlate of poor outcomes. This phenomenon results from oxidative stress, with NO "scavenging" and dysfunction of soluble guanylate cyclase (sGC). Thioredoxin-interacting protein (TXNIP) is a major intracellular regulator of inflammatory activation and redox stress, but its interactions with NO/sGC are poorly understood. We have now evaluated the relationship between platelet TXNIP expression and function of the NO/sGC axis in subjects of varying age and during therapy with ramipril. METHODS & RESULTS Young (n=42) and aging (n=49) subjects underwent evaluation of platelet TXNIP content. Aging subjects additionally had measurements of platelet NO responsiveness and routine biochemistry. Platelet TXNIP content was greater (376±33 units) in the aging compared to younger subjects (289±13 units; p<0.05). In the aging subjects there was a significant negative correlation (r=-0.50, p<0.001) between platelet TXNIP content and NO responsiveness. In a separate cohort of 15 subjects two week treatment with ramipril, which reversed platelet NO resistance and potentiated sGC activity, also decreased platelet TXNIP content by 40% (p=0.011). CONCLUSIONS Platelet TXNIP content increases with aging, varies inversely with responsiveness to NO, and diminishes rapidly following treatment with ramipril. These data suggest that TXNIP-induced oxidative stress may be a critical modulator of tissue resistance to NO, a fundamental basis for cardiovascular disease. Analogously suppression of TXNIP expression can potentially be utilized as an index of restoration of cardiovascular homeostasis.
Collapse
Affiliation(s)
- Aaron L Sverdlov
- Cardiology Unit, Basil Hetzel Institute, The Queen Elizabeth Hospital, University of Adelaide, Adelaide, Australia
| | | | | | | | | | | |
Collapse
|