151
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Taylor R, Al-Mrabeh A, Sattar N. Understanding the mechanisms of reversal of type 2 diabetes. Lancet Diabetes Endocrinol 2019; 7:726-736. [PMID: 31097391 DOI: 10.1016/s2213-8587(19)30076-2] [Citation(s) in RCA: 138] [Impact Index Per Article: 27.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/13/2018] [Revised: 01/08/2019] [Accepted: 01/11/2019] [Indexed: 12/13/2022]
Abstract
Clinical and pathophysiological studies have shown type 2 diabetes to be a condition mainly caused by excess, yet reversible, fat accumulation in the liver and pancreas. Within the liver, excess fat worsens hepatic responsiveness to insulin, leading to increased glucose production. Within the pancreas, the β cell seems to enter a survival mode and fails to function because of the fat-induced metabolic stress. Removal of excess fat from these organs via substantial weight loss can normalise hepatic insulin responsiveness and, in the early years post-diagnosis, is associated with β-cell recovery of acute insulin secretion in many individuals, possibly by redifferentiation. Collectively, these changes can normalise blood glucose levels. Importantly, the primary care-based Diabetes Remission Clinical Trial (DiRECT) showed that 46% of people with type 2 diabetes could achieve remission at 12 months, and 36% at 24 months, mediated by weight loss. This major change in our understanding of the underlying mechanisms of disease permits a reassessment of advice for people with type 2 diabetes.
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Affiliation(s)
- Roy Taylor
- Newcastle Magnetic Resonance Centre, Institute of Cellular Medicine, Newcastle University, Newcastle upon Tyne, UK.
| | - Ahmad Al-Mrabeh
- Newcastle Magnetic Resonance Centre, Institute of Cellular Medicine, Newcastle University, Newcastle upon Tyne, UK
| | - Naveed Sattar
- Institute of Cardiovascular and Medical Sciences, University of Glasgow, Glasgow, UK
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152
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Shakib Z, Shahraki N, Razavi BM, Hosseinzadeh H. Aloe vera as an herbal medicine in the treatment of metabolic syndrome: A review. Phytother Res 2019; 33:2649-2660. [PMID: 31456283 DOI: 10.1002/ptr.6465] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2019] [Revised: 07/06/2019] [Accepted: 07/09/2019] [Indexed: 12/13/2022]
Abstract
Metabolic syndrome (MS) is a highly prevalent health problem worldwide and is associated with different risk factors, including hyperglycemia, dyslipidemia, hypertension, and obesity. This condition increases the risk of developing type II diabetes mellitus and cardiovascular problems. The MS is one of the most important health concerns in industrialized countries and mainly results from a sedentary lifestyle, high levels of subjective stress, and unhealthy diets. Nowadays, the identification of appropriate health care approaches, such as herbal medicines, with fewer side effects is more favorable, especially with regard to the adverse effects of chemical drugs. Aloe barbadensis Miller known as Aloe vera is a useful plant with two major parts, including leaves that contain high concentrations of anthraquinone compounds and a clear gel. The gel is used as a food with several beneficial properties, such as antiinflammatory, antioxidant, antiviral, antibacterial, and wound-healing features. Other effects of A. vera, such as its lipid-lowering, antihypertensive, antidiabetic, antiobesity, and cardioprotective impacts, have been demonstrated in several studies. The present study was conducted to review the evidence on the pharmacological effects of A. vera on the different components of MS.
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Affiliation(s)
- Zahra Shakib
- School of Pharmacy, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Naghmeh Shahraki
- School of Pharmacy, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Bibi Marjan Razavi
- Targeted Drug Delivery Research Center, Pharmaceutical Technology Institute, Mashhad University of Medical Sciences, Mashhad, Iran
- Department of Pharmacodynamics and Toxicology, School of Pharmacy, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Hossein Hosseinzadeh
- Pharmaceutical Research Center, Pharmaceutical Technology Institute, Mashhad University of Medical Sciences, Mashhad, Iran
- Department of Pharmacodynamics and Toxicology, School of Pharmacy, Mashhad University of Medical Sciences, Mashhad, Iran
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153
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Changes in Plasma Free Fatty Acids Associated with Type-2 Diabetes. Nutrients 2019; 11:nu11092022. [PMID: 31466350 PMCID: PMC6770316 DOI: 10.3390/nu11092022] [Citation(s) in RCA: 163] [Impact Index Per Article: 32.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2019] [Revised: 08/22/2019] [Accepted: 08/24/2019] [Indexed: 02/06/2023] Open
Abstract
Type 2 diabetes mellitus (T2DM) is associated with increased total plasma free fatty acid (FFA) concentrations and an elevated risk of cardiovascular disease. The exact mechanisms by which the plasma FFA profile of subjects with T2DM changes is unclear, but it is thought that dietary fats and changes to lipid metabolism are likely to contribute. Therefore, establishing the changes in concentrations of specific FFAs in an individual’s plasma is important. Each type of FFA has different effects on physiological processes, including the regulation of lipolysis and lipogenesis in adipose tissue, inflammation, endocrine signalling and the composition and properties of cellular membranes. Alterations in such processes due to altered plasma FFA concentrations/profiles can potentially result in the development of insulin resistance and coagulatory defects. Finally, fibrates and statins, lipid-regulating drugs prescribed to subjects with T2DM, are also thought to exert part of their beneficial effects by impacting on plasma FFA concentrations. Thus, it is also interesting to consider their effects on the concentration of FFAs in plasma. Collectively, we review how FFAs are altered in T2DM and explore the likely downstream physiological and pathological implications of such changes.
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154
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Zhu Y, Zhang X, Zhang L, Zhang M, Li L, Luo D, Zhong Y. Perilipin5 protects against lipotoxicity and alleviates endoplasmic reticulum stress in pancreatic β-cells. Nutr Metab (Lond) 2019; 16:50. [PMID: 31384284 PMCID: PMC6668071 DOI: 10.1186/s12986-019-0375-2] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2018] [Accepted: 07/19/2019] [Indexed: 12/27/2022] Open
Abstract
Background Chronic exposure of pancreatic β-cells to excess free fatty acids is thought to contribute to type 2 diabetes pathogenesis in obesity by impairing β-cell function and even leading to apoptosis. In β-cells, lipid droplet-associated protein perilipin 5 (PLIN5) has been shown to enhance insulin secretion by regulating intracellular lipid metabolism; the roles of PLIN5 in response to lipotoxicity remain poorly understood. Methods INS-1 β-cells were transfected with PLIN5-overexpression adenovirus (Ad-PLIN5) and treated with palmitate. C57BL/6 J male mice were fed with high fat diet and tail intravenous injected with adeno-associated virus overexpressing PLIN5 (AAV-PLIN5) in β-cells. Results Our data showed that palmitate and PPAR agonists including WY14643 (PPARα), GW501516 (PPARβ/δ), rosiglitazone (PPARγ) in vitro all induced PLIN5 expression in INS-1 cells. Under palmitate overload, although upregulating PLIN5 promoted lipid droplet storage, it alleviated lipotoxicity in INS-1 β-cells with improved cell viability, cell apoptosis and β-cell function. The protection role of PLIN5 in β-cell function observed in cell experiments were further verified in in vivo study indicated by mitigated glucose intolerance in high fat diet fed mice with β-cell-specific overexpression of PLIN5. Mechanistic experiments revealed that enhanced FAO induced by elevation of PLIN5, followed by decreased ER stress may be a major mechanism responsible for alleviation of lipotoxicity observed in the present study. Conclusions Our finding substantiated the important role of PLIN5 in protection against lipotoxicity in β-cells. Electronic supplementary material The online version of this article (10.1186/s12986-019-0375-2) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Yunxia Zhu
- 1Department of Geriatrics, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, No.600, Yishan Road, Shanghai, 200233 China
| | - Xiaoyan Zhang
- 1Department of Geriatrics, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, No.600, Yishan Road, Shanghai, 200233 China
| | - Li Zhang
- 1Department of Geriatrics, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, No.600, Yishan Road, Shanghai, 200233 China
| | - Mingliang Zhang
- 2Department of Endocrinology and Metabolism, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai, 200233 China
| | - Ling Li
- 3Department of Endocrinology, Tongji Hospital, Tongji University School of Medicine, Shanghai, 200065 China
| | - Deng Luo
- 4Department of Endocrinology, Renmin Hospital of Wuhan University, Wuhan, 430060 China
| | - Yuan Zhong
- 1Department of Geriatrics, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, No.600, Yishan Road, Shanghai, 200233 China
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155
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Huang CC, Kuo CY, Yang CY, Liu JM, Hsu RJ, Lee KI, Su CC, Wu CC, Lin CT, Liu SH, Huang CF. Cadmium exposure induces pancreatic β-cell death via a Ca 2+-triggered JNK/CHOP-related apoptotic signaling pathway. Toxicology 2019; 425:152252. [PMID: 31348969 DOI: 10.1016/j.tox.2019.152252] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2019] [Revised: 07/07/2019] [Accepted: 07/22/2019] [Indexed: 01/01/2023]
Abstract
Cadmium (Cd) is known to be ranked the 7th hazardous substance in the Substance Priority List by Agency for Toxic Substances and Disease Registry. The experimental and epidemiological data have suggested that Cd is linked to the development of diabetes mellitus (DM). The molecular mechanism of Cd on the pancreatic β-cell cytotoxicity still remains unclear. Evidence has pointed toward that Ca2+ is an important regulator of toxic insult-induced β-cell cytotoxicity. The role of Ca2+ in the Cd-induced β-cell cytotoxicity is still unknown. In this study, we found that Cd exposure significantly inhibited insulin secretion and cell viability in the pancreatic β-cell-derived RIN-m5F cells. Cd exposure induced apoptotic events, including the increased populations of apoptotic cells and sub-G1 hypodiploid cells, and caspase-3/-7/-9 and poly (ADP-ribose) polymerase (PARP) activation, which largely depended on the activation of c-Jun N-terminal kinase (JNK) and C/EBP homologous protein (CHOP). Transfection with siRNAs for JNK and CHOP or pretreatment with specific pharmacological inhibitor of JNK (SP600125) in β-cells effectively prevented the Cd-induced insulin secretion dysfunction and apoptosis. JNK-specific siRNA dramatically suppressed Cd-induced JNK phosphorylation and CHOP protein expression, but JNK phosphorylation could not be inhibited by CHOP-specific siRNA. Furthermore, Cd exposure significantly increased the intracellular calcium ([Ca2+]i) levels. Buffering the Ca2+ response with BAPTA/AM effectively abrogated the Cd-induced [Ca2+]i elevation, insulin secretion dysfunction, apoptosis, and protein expression of JNK phosphorylation and CHOP activation. Taken together, these findings demonstrated that Cd exposure exerts β-cell death via a [Ca2+]i-dependent JNK activation-activated downstream CHOP-related apoptotic signaling pathway.
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Affiliation(s)
- Cheng-Chin Huang
- Department of Emergency, Taichung Tzu Chi Hospital, Buddhist Tzu Chi Medical Foundation, Taichung, 427, Taiwan
| | - Chun-Ying Kuo
- Department of Otorhinolaryngology, Head and Neck Surgery, Changhua Christian Hospital, Changhua County, 500, Taiwan
| | - Ching-Yao Yang
- Department of Surgery, National Taiwan University Hospital, and Department of Surgery, College of Medicine, National Taiwan University, Taipei, 100, Taiwan
| | - Jui-Ming Liu
- Division of Urology, Department of Surgery, Taoyuan General Hospital, Ministry of Health and Welfare, Taoyuan, 330, Taiwan
| | - Ren-Jun Hsu
- Department of Pathology and Graduate Institute of Pathology and Parasitology, Tri-Service General Hospital, National Defense Medical Center, Taipei, 114, Taiwan; Graduate Institute of Life Sciences, National Defense Medical Center, Taipei, 114, Taiwan
| | - Kuan-I Lee
- Department of Emergency, Taichung Tzu Chi Hospital, Buddhist Tzu Chi Medical Foundation, Taichung, 427, Taiwan
| | - Chin-Chuan Su
- Department of Otorhinolaryngology, Head and Neck Surgery, Changhua Christian Hospital, Changhua County, 500, Taiwan
| | - Chin-Ching Wu
- Department of Public Health, China Medical University, Taichung, 404, Taiwan
| | - Ching-Ting Lin
- School of Chinese Medicine, College of Chinese Medicine, China Medical University, Taichung, 404, Taiwan
| | - Shing-Hwa Liu
- Institute of Toxicology, College of Medicine, National Taiwan University, Taipei, 100, Taiwan.
| | - Chun-Fa Huang
- School of Chinese Medicine, College of Chinese Medicine, China Medical University, Taichung, 404, Taiwan; Department of Nursing, College of Medical and Health Science, Asia University, Taichung, 413, Taiwan.
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156
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Carlessi R, Rowlands J, Ellison G, Helena de Oliveira Alves H, Newsholme P, Mamotte C. Glutamine deprivation induces metabolic adaptations associated with beta cell dysfunction and exacerbate lipotoxicity. Mol Cell Endocrinol 2019; 491:110433. [PMID: 31018148 DOI: 10.1016/j.mce.2019.04.013] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/15/2019] [Revised: 04/05/2019] [Accepted: 04/15/2019] [Indexed: 11/17/2022]
Abstract
Studies have reported that plasma glutamine is reduced in type 2 diabetes (T2D) patients. Glutamine supplementation improves glycaemic control, however the mechanisms are unclear. Here, we evaluated in vitro the pancreatic beta cell bioenergetic and insulin secretory responses to various levels of glutamine availability, or treatment in the presence of an inhibitor of intracellular glutamine metabolism. The impact of glutamine deprivation to the pathological events induced by the saturated fatty acid palmitate was also investigated. Glutamine deprivation induced a reduction in mitochondrial respiration and increase in glucose uptake and utilization. This phenotype was accompanied by impairment in beta cell function, as demonstrated by diminished insulin production and secretion, and activation of the unfolded protein response pathway. Palmitate led to insulin secretory dysfunction, loss of viability and apoptosis. Importantly, glutamine deprivation significantly exacerbated these phenotypes, suggesting that low glutamine levels could participate in the process of beta cell dysfunction in T2D.
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Affiliation(s)
- Rodrigo Carlessi
- School of Pharmacy and Biomedical Sciences, Curtin Health Innovation Research Institute, Perth, Western Australia, 6845, Australia.
| | - Jordan Rowlands
- School of Pharmacy and Biomedical Sciences, Curtin Health Innovation Research Institute, Perth, Western Australia, 6845, Australia
| | - Gaewyn Ellison
- School of Pharmacy and Biomedical Sciences, Curtin Health Innovation Research Institute, Perth, Western Australia, 6845, Australia
| | | | - Philip Newsholme
- School of Pharmacy and Biomedical Sciences, Curtin Health Innovation Research Institute, Perth, Western Australia, 6845, Australia.
| | - Cyril Mamotte
- School of Pharmacy and Biomedical Sciences, Curtin Health Innovation Research Institute, Perth, Western Australia, 6845, Australia.
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157
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Zhang B, Zeng M, Li M, Chen W, Li B, Kan Y, Feng W, Zheng X. Guaiane-Type Sesquiterpenoids From Dendranthema morifolium (Ramat.) S. Kitam Flowers Protect H9c2 Cardiomyocyte From LPS-Induced Injury. Nat Prod Commun 2019. [DOI: 10.1177/1934578x19864179] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
This study investigated the protective effects of guaiane-type sesquiterpenoids isolated from Dendranthema morifolium (Ramat.) S. Kitam flowers on lipopolysaccharide (LPS)-induced injury in H9c2 cardiomyocyte. Cell viability was determined by thiazolyl blue tetrazolium bromide (MTT). The content of released tumor necrosis factor alpha (TNF- α) and interleukin 6 (IL-6) was evaluated by enzyme-linked immunosorbent assay. The levels of lactate dehydrogenase (LDH) and creatine phosphate kinase (CK) were measured by using commercial available kits. The protein expression levels of pelF2 α, GRP78, Bax, caspase-3, caspase-9, Bcl-2, LC3-II, and p62 were measured by in-cell Western. Flow cytometry was used to detect H9c2 cardiomyocyte apoptosis. Compounds 5, 7, 1, 8, and 2 exhibited the effects of cardioprotection and activity sequence enhancement. The levels of IL-6, TNF- α, LDH, CK, pelF2 α, GRP78, Bax, caspase-3, caspase-9, p62, and H9c2 cardiomyocyte apoptosis were increased in LPS-treated H9c2 cardiomyocyte, while those of Bcl-2 and LC3-II were decreased. These effects could be effectively reversed by compounds 5, 7, 1, 8, and 2. Results demonstrated that the guaiane-type sesquiterpenoids could prevent LPS-induced injury in cardiomyocyte by decreasing endoplasmic reticulum (ER) stress, apoptosis, and autophagy as well as downregulating the inflammatory mediators. In addition, the active groups of guaiane-type sesquiterpenoids might be the angelate at C-8 and the exocyclic double bond at C-11.
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Affiliation(s)
- Beibei Zhang
- Henan University of Chinese Medicine, Zhengzhou, China
- Collaborative Innovation Center for Respiratory Disease Diagnosis and Treatment & Chinese Medicine Development of Henan Province, Zhengzhou, China
| | - Mengnan Zeng
- Henan University of Chinese Medicine, Zhengzhou, China
- Collaborative Innovation Center for Respiratory Disease Diagnosis and Treatment & Chinese Medicine Development of Henan Province, Zhengzhou, China
| | - Meng Li
- Henan University of Chinese Medicine, Zhengzhou, China
- Collaborative Innovation Center for Respiratory Disease Diagnosis and Treatment & Chinese Medicine Development of Henan Province, Zhengzhou, China
| | - Wenjing Chen
- Henan University of Chinese Medicine, Zhengzhou, China
- Collaborative Innovation Center for Respiratory Disease Diagnosis and Treatment & Chinese Medicine Development of Henan Province, Zhengzhou, China
| | - Benke Li
- Henan University of Chinese Medicine, Zhengzhou, China
- Collaborative Innovation Center for Respiratory Disease Diagnosis and Treatment & Chinese Medicine Development of Henan Province, Zhengzhou, China
| | - Yuxuan Kan
- Henan University of Chinese Medicine, Zhengzhou, China
- Collaborative Innovation Center for Respiratory Disease Diagnosis and Treatment & Chinese Medicine Development of Henan Province, Zhengzhou, China
| | - Weisheng Feng
- Henan University of Chinese Medicine, Zhengzhou, China
- Collaborative Innovation Center for Respiratory Disease Diagnosis and Treatment & Chinese Medicine Development of Henan Province, Zhengzhou, China
| | - Xiaoke Zheng
- Henan University of Chinese Medicine, Zhengzhou, China
- Collaborative Innovation Center for Respiratory Disease Diagnosis and Treatment & Chinese Medicine Development of Henan Province, Zhengzhou, China
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158
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Huang XT, Liu W, Zhou Y, Sun M, Sun CC, Zhang CY, Tang SY. Endoplasmic reticulum stress contributes to NMDA-induced pancreatic β-cell dysfunction in a CHOP-dependent manner. Life Sci 2019; 232:116612. [PMID: 31260687 DOI: 10.1016/j.lfs.2019.116612] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2019] [Revised: 06/17/2019] [Accepted: 06/27/2019] [Indexed: 01/09/2023]
Abstract
AIMS Accumulating evidence suggest that endoplasmic reticulum (ER) stress is an important mechanism underlying the development of diabetes. We have reported that sustained treatment with N-methyl-d-aspartate (NMDA) results in apoptotic β-cell death and impairs insulin secretion. However, the molecular mechanism responsible for NMDA-induced β-cell dysfunction remains largely obscure. Thus, this study aimed to determine whether sustained activation of NMDA receptors (NMDARs) causes β-cell dysfunction through ER stress. MAIN METHODS Primary mouse islets and MIN6 mouse pancreatic β-cells were treated with NMDA for 24 h or high-glucose for 72 h. After the treatment, glucose-stimulated insulin secretion (GSIS) and the expression of ER stress markers were measured, respectively. In vivo, the expression of ER stress markers was measured in the pancreas of diabetic mice treated with or without NMDARs inhibitor Memantine. KEY FINDINGS NMDA treatment caused an increase in the expression of ER stress markers (ATF4, CHOP, GRP78, and Xbp1s) in primary islets. While, tauroursodeoxycholic acid (TUDCA), an inhibitor of ER stress, significantly attenuated NMDA-induced β-cell dysfunction, including the loss of glucose-stimulated insulin secretion and reduction of pancreas duodenum homeobox factor-1 (Pdx-1) mRNA expression, a transcription factor regulating insulin synthesis. Besides, NMDA-induced ER stress strongly promoted pro-inflammatory cytokines synthesis (IL-1β and TNF-α) in β cells. Interestingly, knockdown of CHOP attenuated β-cell dysfunction evoked by NMDA. Furthermore, we demonstrated that blockade of NMDARs ameliorated high-glucose-induced ER stress in vitro and in vivo. SIGNIFICANCE This study confirms that ER stress is actively involved in the activation of NMDARs-related β-cell dysfunction.
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Affiliation(s)
- Xiao-Ting Huang
- Xiangya Nursing School, Central South University, Changsha, Hunan, China
| | - Wei Liu
- Xiangya Nursing School, Central South University, Changsha, Hunan, China
| | - Yong Zhou
- Department of Physiology, Xiangya School of Medicine, Central South University, Changsha, Hunan, China
| | - Mei Sun
- Xiangya Nursing School, Central South University, Changsha, Hunan, China
| | - Chen-Chen Sun
- Department of Physiology, Xiangya School of Medicine, Central South University, Changsha, Hunan, China
| | - Chen-Yu Zhang
- Department of Physiology, Xiangya School of Medicine, Central South University, Changsha, Hunan, China
| | - Si-Yuan Tang
- Xiangya Nursing School, Central South University, Changsha, Hunan, China.
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159
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Arunagiri A, Haataja L, Pottekat A, Pamenan F, Kim S, Zeltser LM, Paton AW, Paton JC, Tsai B, Itkin-Ansari P, Kaufman RJ, Liu M, Arvan P. Proinsulin misfolding is an early event in the progression to type 2 diabetes. eLife 2019; 8:44532. [PMID: 31184302 PMCID: PMC6559786 DOI: 10.7554/elife.44532] [Citation(s) in RCA: 89] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2018] [Accepted: 04/09/2019] [Indexed: 02/06/2023] Open
Abstract
Biosynthesis of insulin – critical to metabolic homeostasis – begins with folding of the proinsulin precursor, including formation of three evolutionarily conserved intramolecular disulfide bonds. Remarkably, normal pancreatic islets contain a subset of proinsulin molecules bearing at least one free cysteine thiol. In human (or rodent) islets with a perturbed endoplasmic reticulum folding environment, non-native proinsulin enters intermolecular disulfide-linked complexes. In genetically obese mice with otherwise wild-type islets, disulfide-linked complexes of proinsulin are more abundant, and leptin receptor-deficient mice, the further increase of such complexes tracks with the onset of islet insulin deficiency and diabetes. Proinsulin-Cys(B19) and Cys(A20) are necessary and sufficient for the formation of proinsulin disulfide-linked complexes; indeed, proinsulin Cys(B19)-Cys(B19) covalent homodimers resist reductive dissociation, highlighting a structural basis for aberrant proinsulin complex formation. We conclude that increased proinsulin misfolding via disulfide-linked complexes is an early event associated with prediabetes that worsens with ß-cell dysfunction in type two diabetes. Our body fine-tunes the amount of sugar in our blood thanks to specialized ‘beta cells’ in the pancreas, which can release a hormone called insulin. To produce insulin, the beta cells first need to build an early version of the molecule – known as proinsulin – inside a cellular compartment called the endoplasmic reticulum. This process involves the formation of internal staples that keep the molecule of proinsulin folded correctly. Individuals developing type 2 diabetes have spikes of sugar in their blood, and so their bodies often respond by trying to make large amounts of insulin. After a while, the beta cells can fail to keep up, which brings on the full-blown disease. However, scientists have discovered that early in type 2 diabetes, the endoplasmic reticulum of beta cells can already show signs of stress; yet, the exact causes of this early damage are still unknown. To investigate this, Arunagiri et al. looked into whether proinsulin folds correctly during the earliest stages of type 2 diabetes. Biochemical experiments showed that even healthy beta cells contained some misfolded proinsulin molecules, where the molecular staples that should fold proinsulin internally were instead abnormally linking proinsulin molecules together. Further work revealed that the misfolded proinsulin was accumulating inside the endoplasmic reticulum. Finally, obese mice that were in the earliest stages of type 2 diabetes had the highest levels of abnormal proinsulin in their beta cells. Overall, the work by Arunagiri et al. suggests that large amounts of proinsulin molecules stapling themselves to each other in the endoplasmic reticulum of beta cells could be an early hallmark of the disease, and could make it get worse. A separate study by Jang et al. also shows that a protein that limits the misfolding of proinsulin is key to maintain successful insulin production in animals eating a Western-style, high fat diet. Hundreds of millions of people around the world have type 2 diabetes, and this number is rising quickly. Detecting and then fixing early problems associated with the condition may help to stop the disease in its track.
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Affiliation(s)
- Anoop Arunagiri
- Division of Metabolism, Endocrinology & Diabetes, University of Michigan Medical School, Ann Arbor, United States
| | - Leena Haataja
- Division of Metabolism, Endocrinology & Diabetes, University of Michigan Medical School, Ann Arbor, United States
| | - Anita Pottekat
- Degenerative Diseases Program, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, United States
| | - Fawnnie Pamenan
- Division of Metabolism, Endocrinology & Diabetes, University of Michigan Medical School, Ann Arbor, United States
| | - Soohyun Kim
- Department of Biomedical Science and Technology, Konkuk University, Gwangjin-gu, Republic of Korea
| | - Lori M Zeltser
- Department of Pathology and Cell Biology, Naomi Berrie Diabetes Center, Columbia University, New York, United States
| | - Adrienne W Paton
- Research Centre for Infectious Diseases, Department of Molecular and Biomedical Science, University of Adelaide, Adelaide, Australia
| | - James C Paton
- Research Centre for Infectious Diseases, Department of Molecular and Biomedical Science, University of Adelaide, Adelaide, Australia
| | - Billy Tsai
- Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, United States
| | - Pamela Itkin-Ansari
- Development, Aging and Regeneration Program, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, United States
| | - Randal J Kaufman
- Degenerative Diseases Program, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, United States
| | - Ming Liu
- Division of Metabolism, Endocrinology & Diabetes, University of Michigan Medical School, Ann Arbor, United States.,Department of Endocrinology and Metabolism, Tianjin Medical University, Tianjin, China
| | - Peter Arvan
- Division of Metabolism, Endocrinology & Diabetes, University of Michigan Medical School, Ann Arbor, United States
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160
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Bennett MK, Wallington-Beddoe CT, Pitson SM. Sphingolipids and the unfolded protein response. Biochim Biophys Acta Mol Cell Biol Lipids 2019; 1864:1483-1494. [PMID: 31176037 DOI: 10.1016/j.bbalip.2019.06.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2019] [Revised: 05/29/2019] [Accepted: 06/01/2019] [Indexed: 12/17/2022]
Abstract
The unfolded protein response (UPR) is a response by the endoplasmic reticulum to stress, classically caused by any disruption to cell homeostasis that results in an accumulation in unfolded proteins. However, there is an increasing body of research demonstrating that the UPR can also be activated by changes in lipid homeostasis, including changes in sphingolipid metabolism. Sphingolipids are a family of bioactive lipids with important roles in both the formation and integrity of cellular membranes, and regulation of key cellular processes, including cell proliferation and apoptosis. Bi-directional interactions between sphingolipids and the UPR have now been observed in a range of diseases, including cancer, diabetes and liver disease. Determining how these two key cellular components influence each other could play an important role in deciphering the causes of these diseases and potentially reveal new therapeutic approaches.
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Affiliation(s)
- Melissa K Bennett
- Centre for Cancer Biology, University of South Australia and SA Pathology, UniSA CRI Building, North Tce, Adelaide, SA 5001, Australia
| | - Craig T Wallington-Beddoe
- Centre for Cancer Biology, University of South Australia and SA Pathology, UniSA CRI Building, North Tce, Adelaide, SA 5001, Australia; Adelaide Medical School, University of Adelaide, Adelaide, SA 5001, Australia; Flinders Medical Centre, Bedford Park, SA 5042, Australia; College of Medicine and Public Health, Flinders University, Bedford Park, SA 5042, Australia
| | - Stuart M Pitson
- Centre for Cancer Biology, University of South Australia and SA Pathology, UniSA CRI Building, North Tce, Adelaide, SA 5001, Australia; Adelaide Medical School, University of Adelaide, Adelaide, SA 5001, Australia; School of Biological Sciences, University of Adelaide, Adelaide, SA 5000, Australia.
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161
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Mooranian A, Zamani N, Takechi R, Luna G, Mikov M, Goločorbin-Kon S, Elnashar M, Arfuso F, Al-Salami H. An in vivo pharmacological study: Variation in tissue-accumulation for the drug probucol as the result of targeted microtechnology and matrix-acrylic acid optimization and stabilization techniques. PLoS One 2019; 14:e0214984. [PMID: 30947243 PMCID: PMC6449070 DOI: 10.1371/journal.pone.0214984] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2018] [Accepted: 03/26/2019] [Indexed: 11/18/2022] Open
Abstract
Type 2 diabetes (T2D) is characterised by β-cell damage and hyperglycaemia. The lipophilic drug, probucol, has shown significant β-cell protective and potential antidiabetic effects, which were enhanced by hydrophilic bile acid incorporation using taurocholic acid and chenodeoxycholic acid. However, probucol has severe cardiotoxicity and a variable absorption profile, which limit its potential applications in T2D. Accordingly, this study aimed to design multiple formulations to optimise probucol oral delivery in T2D and test their effects on probucol absorption and accumulation in the heart. Adult male mice were given a high fat diet (HFD), and a week later, injected with a single dose of alloxan to accelerate T2D development, and once diabetes confirmed, divided into three groups (six to seven mice each). The groups were gavaged a daily dose of probucol powder, probucol microcapsules, or probucol-bile acid microcapsules for three months, and euthanized; and blood, tissues, and feces collected for blood glucose and probucol concentration analyses. Probucol concentrations in plasma were similar among all the groups. Groups given probucol microcapsules and probucol-bile acid microcapsules showed significant reduction in probucol accumulation in the heart compared with the group given probucol powder (p<0.05). Probucol microencapsulation with or without bile acids reduced its accumulation in heart tissues, without changing plasma concentrations, which may be beneficial in reducing its cardiotoxicity and optimise its potential applications in T2D.
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Affiliation(s)
- Armin Mooranian
- Biotechnology and Drug Development Research Laboratory, School of Pharmacy and Biomedical Sciences, Curtin Health Innovation Research Institute, Curtin University, Perth, Western Australia, Australia
| | - Nassim Zamani
- Biotechnology and Drug Development Research Laboratory, School of Pharmacy and Biomedical Sciences, Curtin Health Innovation Research Institute, Curtin University, Perth, Western Australia, Australia
| | - Ryu Takechi
- School of Public Health, Curtin Health Innovation Research Institute, Curtin University, Perth, Western Australia, Australia
| | - Giuseppe Luna
- Biotechnology and Drug Development Research Laboratory, School of Pharmacy and Biomedical Sciences, Curtin Health Innovation Research Institute, Curtin University, Perth, Western Australia, Australia
| | - Momir Mikov
- Department of Pharmacology, Toxicology and Clinical Pharmacology, Faculty of Medicine, University of Novi Sad, Novi Sad, Serbia
| | | | - Magdy Elnashar
- Biotechnology and Drug Development Research Laboratory, School of Pharmacy and Biomedical Sciences, Curtin Health Innovation Research Institute, Curtin University, Perth, Western Australia, Australia
| | - Frank Arfuso
- Stem Cell and Cancer Biology Laboratory, School of Pharmacy and Biomedical Sciences, Curtin Health Innovation Research Institute, Curtin University, Perth, Western Australia, Australia
| | - Hani Al-Salami
- Biotechnology and Drug Development Research Laboratory, School of Pharmacy and Biomedical Sciences, Curtin Health Innovation Research Institute, Curtin University, Perth, Western Australia, Australia
- * E-mail:
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162
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Zhao Y, Yu Y, Li H, Zhang Z, Guo S, Zhu S, Guo Q, Li P, Min L, Zhang S. FAM175B promotes apoptosis by inhibiting ATF4 ubiquitination in esophageal squamous cell carcinoma. Mol Oncol 2019; 13:1150-1165. [PMID: 30854784 PMCID: PMC6487841 DOI: 10.1002/1878-0261.12474] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2018] [Revised: 01/30/2019] [Accepted: 02/25/2019] [Indexed: 11/07/2022] Open
Abstract
FAM175B is a reported regulator of p53 and suppresses tumorigenesis in numerous types of cancer, but very little is known about its function in esophageal squamous cell carcinomas (ESCCs), almost 70% of which exhibit mutations in p53. Here, we report that FAM175B expression is downregulated in high-grade intraepithelial neoplasia (t = 2.44, P = 0.031) and ESCC (t = 5.664, P < 0.001) tissues relative to that in adjacent normal esophageal tissues. Exogenous expression of FAM175B in ESCC cells resulted in a decrease in proliferation rate, inhibition of colony formation, and an increase in apoptosis rate. Knockdown of FAM175B produced the opposite results. Furthermore, confocal microscopy and coimmunoprecipitation assay showed that Activating transcription factor 4 (ATF4) colocalized and interacted with FAM175B. Ubiquitination assays revealed that FAM175B inhibited ubiquitin-dependent ATF4 degradation and elevated ATF4 protein level. Finally, luciferase reporter experiments further clarified that FAM175B promoted CHOP expression in an ATF4-dependent manner. Accordingly, the proapoptotic activity of FAM175B was significantly rescued by treatment with si-ATF4 and the CHOP inhibitor 4-PBA. In summary, FAM175B inhibited ATF4 ubiquitination and promoted ESCC cell apoptosis in a p53-independent manner. FAM175B expression loss may be an early diagnostic biomarker in ESCC patients.
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Affiliation(s)
- Yu Zhao
- Beijing Key Laboratory for Precancerous Lesion of Digestive Disease, Department of Gastroenterology, National Clinical Research Center for Digestive Disease, Beijing Digestive Disease Center, Beijing Friendship Hospital, Capital Medical University, Beijing, China
| | - Yang Yu
- Beijing Key Laboratory for Precancerous Lesion of Digestive Disease, Department of Gastroenterology, National Clinical Research Center for Digestive Disease, Beijing Digestive Disease Center, Beijing Friendship Hospital, Capital Medical University, Beijing, China
| | - Hengcun Li
- Beijing Key Laboratory for Precancerous Lesion of Digestive Disease, Department of Gastroenterology, National Clinical Research Center for Digestive Disease, Beijing Digestive Disease Center, Beijing Friendship Hospital, Capital Medical University, Beijing, China
| | - Zheng Zhang
- Beijing Key Laboratory for Precancerous Lesion of Digestive Disease, Department of Gastroenterology, National Clinical Research Center for Digestive Disease, Beijing Digestive Disease Center, Beijing Friendship Hospital, Capital Medical University, Beijing, China
| | - Shuilong Guo
- Beijing Key Laboratory for Precancerous Lesion of Digestive Disease, Department of Gastroenterology, National Clinical Research Center for Digestive Disease, Beijing Digestive Disease Center, Beijing Friendship Hospital, Capital Medical University, Beijing, China
| | - Shengtao Zhu
- Beijing Key Laboratory for Precancerous Lesion of Digestive Disease, Department of Gastroenterology, National Clinical Research Center for Digestive Disease, Beijing Digestive Disease Center, Beijing Friendship Hospital, Capital Medical University, Beijing, China
| | - Qingdong Guo
- Beijing Key Laboratory for Precancerous Lesion of Digestive Disease, Department of Gastroenterology, National Clinical Research Center for Digestive Disease, Beijing Digestive Disease Center, Beijing Friendship Hospital, Capital Medical University, Beijing, China
| | - Peng Li
- Beijing Key Laboratory for Precancerous Lesion of Digestive Disease, Department of Gastroenterology, National Clinical Research Center for Digestive Disease, Beijing Digestive Disease Center, Beijing Friendship Hospital, Capital Medical University, Beijing, China
| | - Li Min
- Beijing Key Laboratory for Precancerous Lesion of Digestive Disease, Department of Gastroenterology, National Clinical Research Center for Digestive Disease, Beijing Digestive Disease Center, Beijing Friendship Hospital, Capital Medical University, Beijing, China
| | - Shutian Zhang
- Beijing Key Laboratory for Precancerous Lesion of Digestive Disease, Department of Gastroenterology, National Clinical Research Center for Digestive Disease, Beijing Digestive Disease Center, Beijing Friendship Hospital, Capital Medical University, Beijing, China
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163
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Glavas MM, Hui Q, Tudurí E, Erener S, Kasteel NL, Johnson JD, Kieffer TJ. Early overnutrition reduces Pdx1 expression and induces β cell failure in Swiss Webster mice. Sci Rep 2019; 9:3619. [PMID: 30842440 PMCID: PMC6403421 DOI: 10.1038/s41598-019-39177-3] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2018] [Accepted: 01/07/2019] [Indexed: 12/25/2022] Open
Abstract
Childhood obesity and early rapid growth increase the risk for type 2 diabetes. Such early overnutrition can be modeled in mice by reducing litter size. We investigated the effects of early overnutrition and increased dietary fat intake on β cell function in Swiss Webster mice. On a moderate-fat diet, early overnutrition accelerated weight gain and induced hyperinsulinemia in pups. Early overnutrition males exhibited higher β cell mass but reduced islet insulin content and Pdx1 expression. Males had a high diabetes incidence that was increased by early overnutrition, characterized by a progressive increase in insulin secretion as well as β cell death, indicated by histological analysis and increased circulating miR-375 levels. Females maintained normoglycemia throughout life. High-fat diet (HFD) increased diabetes incidence in males, whereas low-fat diet was completely protective. This protective effect was abolished in early overnutrition males transiently exposed to HFD in early life. Although Swiss Webster mice are not known to be diabetes-prone, the high diabetes incidence suggests an underlying genetic susceptibility that can be induced by overnutrition and increased dietary fat intake in early life. Thus, the nutritional environment in early life may impact long-term β cell function and increase diabetes risk, particularly in genetically susceptible individuals.
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Affiliation(s)
- Maria M Glavas
- Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, BC, Canada
| | - Queenie Hui
- Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, BC, Canada
| | - Eva Tudurí
- Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, BC, Canada.,Centro de Investigación Biomédica en Red de Diabetes y , Enfermedades Metabólicas Asociadas (CIBERDEM), Madrid, Spain
| | - Suheda Erener
- Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, BC, Canada
| | - Naomi L Kasteel
- Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, BC, Canada
| | - James D Johnson
- Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, BC, Canada
| | - Timothy J Kieffer
- Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, BC, Canada. .,Department of Surgery, University of British Columbia, Vancouver, BC, Canada.
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164
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Ye R, Onodera T, Scherer PE. Lipotoxicity and β Cell Maintenance in Obesity and Type 2 Diabetes. J Endocr Soc 2019; 3:617-631. [PMID: 30834357 PMCID: PMC6391718 DOI: 10.1210/js.2018-00372] [Citation(s) in RCA: 54] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/11/2018] [Accepted: 01/30/2019] [Indexed: 12/11/2022] Open
Abstract
Obesity and diabetes are often associated with lipotoxic conditions in multiple tissues. The insulin-producing β cells are susceptible to elevated lipid levels and the ensuing lipotoxicity. The preservation of β cell mass and function is one of the main goals of diabetes management under these metabolically stressful conditions. However, the adverse effects from the adaptive signaling pathways that β cells use to counteract lipotoxic stress have secondary negative effects in their own right. Antilipotoxic signaling cascades in β cells can contribute to their eventual failure. Such dual roles are seen for many other biological adaptive processes as well.
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Affiliation(s)
- Risheng Ye
- Department of Medical Education, Texas Tech University Health Sciences Center Paul L. Foster School of Medicine, El Paso, Texas
- Touchstone Diabetes Center, Department of Internal Medicine, the University of Texas Southwestern Medical Center, Dallas, Texas
| | - Toshiharu Onodera
- Touchstone Diabetes Center, Department of Internal Medicine, the University of Texas Southwestern Medical Center, Dallas, Texas
| | - Philipp E Scherer
- Touchstone Diabetes Center, Department of Internal Medicine, the University of Texas Southwestern Medical Center, Dallas, Texas
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165
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Patel V, Bidault G, Chambers JE, Carobbio S, Everden AJT, Garcés C, Dalton LE, Gribble FM, Vidal-Puig A, Marciniak SJ. Inactivation of Ppp1r15a minimises weight gain and insulin resistance during caloric excess in female mice. Sci Rep 2019; 9:2903. [PMID: 30814564 PMCID: PMC6393541 DOI: 10.1038/s41598-019-39562-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2018] [Accepted: 01/09/2019] [Indexed: 02/02/2023] Open
Abstract
Phosphorylation of the translation initiation factor eIF2α within the mediobasal hypothalamus is known to suppress food intake, but the role of the eIF2α phosphatases in regulating body weight is poorly understood. Mice deficient in active PPP1R15A, a stress-inducible eIF2α phosphatase, are healthy and more resistant to endoplasmic reticulum stress than wild type controls. We report that when female Ppp1r15a mutant mice are fed a high fat diet they gain less weight than wild type littermates owing to reduced food intake. This results in healthy leaner Ppp1r15a mutant animals with reduced hepatic steatosis and improved insulin sensitivity, albeit with a possible modest defect in insulin secretion. By contrast, no weight differences are observed between wild type and Ppp1r15a deficient mice fed a standard diet. We conclude that female mice lacking the C-terminal PP1-binding domain of PPP1R15A show reduced dietary intake and preserved glucose tolerance. Our data indicate that this results in reduced weight gain and protection from diet-induced obesity.
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Affiliation(s)
- Vruti Patel
- 0000000121885934grid.5335.0Cambridge Institute for Medical Research (CIMR), University of Cambridge Wellcome Trust/MRC Building, Hills Road, Cambridge, CB2 0XY UK ,0000000121885934grid.5335.0Department of Medicine, University of Cambridge, Addenbrooke’s Hospital, Hills Rd, Cambridge, CB2 0SP UK
| | - Guillaume Bidault
- 0000 0004 0622 5016grid.120073.7Metabolic Research Laboratories, Wellcome Trust-MRC Institute of Metabolic Science, Addenbrooke’s Hospital, Cambridge, CB2 0QQ UK
| | - Joseph E. Chambers
- 0000000121885934grid.5335.0Cambridge Institute for Medical Research (CIMR), University of Cambridge Wellcome Trust/MRC Building, Hills Road, Cambridge, CB2 0XY UK
| | - Stefania Carobbio
- 0000 0004 0622 5016grid.120073.7Metabolic Research Laboratories, Wellcome Trust-MRC Institute of Metabolic Science, Addenbrooke’s Hospital, Cambridge, CB2 0QQ UK
| | - Angharad J. T. Everden
- 0000000121885934grid.5335.0Cambridge Institute for Medical Research (CIMR), University of Cambridge Wellcome Trust/MRC Building, Hills Road, Cambridge, CB2 0XY UK
| | - Concepción Garcés
- 0000000121885934grid.5335.0Cambridge Institute for Medical Research (CIMR), University of Cambridge Wellcome Trust/MRC Building, Hills Road, Cambridge, CB2 0XY UK
| | - Lucy E. Dalton
- 0000000121885934grid.5335.0Cambridge Institute for Medical Research (CIMR), University of Cambridge Wellcome Trust/MRC Building, Hills Road, Cambridge, CB2 0XY UK
| | - Fiona M. Gribble
- 0000 0004 0622 5016grid.120073.7Metabolic Research Laboratories, Wellcome Trust-MRC Institute of Metabolic Science, Addenbrooke’s Hospital, Cambridge, CB2 0QQ UK
| | - Antonio Vidal-Puig
- 0000 0004 0622 5016grid.120073.7Metabolic Research Laboratories, Wellcome Trust-MRC Institute of Metabolic Science, Addenbrooke’s Hospital, Cambridge, CB2 0QQ UK ,0000 0004 0427 7672grid.52788.30Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, CB10 1SA UK
| | - Stefan J. Marciniak
- 0000000121885934grid.5335.0Cambridge Institute for Medical Research (CIMR), University of Cambridge Wellcome Trust/MRC Building, Hills Road, Cambridge, CB2 0XY UK ,0000000121885934grid.5335.0Department of Medicine, University of Cambridge, Addenbrooke’s Hospital, Hills Rd, Cambridge, CB2 0SP UK
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166
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Bugliani M, Mossuto S, Grano F, Suleiman M, Marselli L, Boggi U, De Simone P, Eizirik DL, Cnop M, Marchetti P, De Tata V. Modulation of Autophagy Influences the Function and Survival of Human Pancreatic Beta Cells Under Endoplasmic Reticulum Stress Conditions and in Type 2 Diabetes. Front Endocrinol (Lausanne) 2019; 10:52. [PMID: 30863363 PMCID: PMC6399112 DOI: 10.3389/fendo.2019.00052] [Citation(s) in RCA: 62] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/06/2018] [Accepted: 01/21/2019] [Indexed: 01/09/2023] Open
Abstract
Autophagy is the major mechanism involved in degradation and recycling of intracellular components, and its alterations have been proposed to cause beta cell dysfunction. In this study, we explored the effects of autophagy modulation in human islets under conditions associated to endoplasmic reticulum (ER) stress. Human pancreatic islets were isolated by enzymatic digestion and density gradient purification from pancreatic samples of non-diabetic (ND; n = 17; age 65 ± 21 years; gender: 5 M/12 F; BMI 23.4 ± 3.3 kg/m2) and T2D (n = 9; age 76 ± 6 years; 4 M/5 F; gender: BMI 25.4 ± 3.7 kg/m2) organ donors. Nine ND organ donors were treated for hypertension and 1 for both hypertension and hypercholesterolemia. T2D organ donors were treated with metformin (1), oral hypoglycemic agents (2), diet + oral hypoglycemic agents (3), insulin (3) or insulin plus metformin (3) as for antidiabetic therapy and, of these, 3 were treated also for hypertension and 6 for both hypertension and hypercholesterolemia. Two days after isolation, they were cultured for 1-5 days with 10 ng/ml rapamycin (autophagy inducer), 5 mM 3-methyladenine or 1.0 nM concanamycin-A (autophagy blockers), either in the presence or not of metabolic (0.5 mM palmitate) or chemical (0.1 ng/ml brefeldin A) ER stressors. In ND islets palmitate exposure induced a 4 to 5-fold increase of beta cell apoptosis, which was significantly prevented by rapamycin and exacerbated by 3-MA. Similar results were observed with brefeldin treatment. Glucose-stimulated insulin secretion from ND islets was reduced by palmitate (-40 to 50%) and brefeldin (-60 to 70%), and rapamycin counteracted palmitate, but not brefeldin, cytotoxic actions. Both palmitate and brefeldin induced PERK, CHOP and BiP gene expression, which was partially, but significantly prevented by rapamycin. With T2D islets, rapamycin alone reduced the amount of p62, an autophagy receptor that accumulates in cells when macroautophagy is inhibited. Compared to untreated T2D cells, rapamycin-exposed diabetic islets showed improved insulin secretion, reduced proportion of beta cells showing signs of apoptosis and better preserved insulin granules, mitochondria and ER ultrastructure; this was associated with significant reduction of PERK, CHOP and BiP gene expression. This study emphasizes the importance of autophagy modulation in human beta cell function and survival, particularly in situations of ER stress. Tuning autophagy could be a tool for beta cell protection.
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Affiliation(s)
- M. Bugliani
- Department of Clinical and Experimental Medicine, University of Pisa, Pisa, Italy
| | - S. Mossuto
- Department of Clinical and Experimental Medicine, University of Pisa, Pisa, Italy
| | - F. Grano
- Department of Clinical and Experimental Medicine, University of Pisa, Pisa, Italy
| | - M. Suleiman
- Department of Clinical and Experimental Medicine, University of Pisa, Pisa, Italy
| | - L. Marselli
- Department of Clinical and Experimental Medicine, University of Pisa, Pisa, Italy
| | - U. Boggi
- Department of Surgical Pathology, Medicine, Molecular and Critical Area, University of Pisa, Pisa, Italy
| | - P. De Simone
- Department of Translational Research and New Technologies in Medicine and Surgery, University of Pisa, Pisa, Italy
| | - D. L. Eizirik
- Medical Faculty, ULB Center for Diabetes Research, Université Libre de Bruxelles, Brussels, Belgium
| | - M. Cnop
- Medical Faculty, ULB Center for Diabetes Research, Université Libre de Bruxelles, Brussels, Belgium
| | - P. Marchetti
- Department of Clinical and Experimental Medicine, University of Pisa, Pisa, Italy
| | - V. De Tata
- Department of Translational Research and New Technologies in Medicine and Surgery, University of Pisa, Pisa, Italy
- *Correspondence: V. De Tata
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167
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Abstract
Starting with a hypothesis which postulated a simple explanation arising from the basic cause of type 2 diabetes, a series of studies has introduced a paradigm shift in our understanding of the condition. Gradual accumulation of fat in the liver and pancreas leads eventually to beta cell dedifferentiation and loss of specialised function. The consequent hyperglycaemia can be returned to normal by removing the excess fat from liver and pancreas. At present this can be achieved only by substantial weight loss, and a simple practical and efficacious method for this has been developed and applied in a series of studies. For those people who used to have type 2 diabetes, the state of post-diabetes can be long term provided that weight regain is avoided. The implications for personal health and for national health economics are considerable.
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Affiliation(s)
- Roy Taylor
- Newcastle University, Newcastle upon Tyne, UK
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168
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Pinto BAS, França LM, Laurindo FRM, Paes AMDA. Unfolded Protein Response: Cause or Consequence of Lipid and Lipoprotein Metabolism Disturbances? ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1127:67-82. [DOI: 10.1007/978-3-030-11488-6_5] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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169
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Chu KY, O'Reilly L, Mellet N, Meikle PJ, Bartley C, Biden TJ. Oleate disrupts cAMP signaling, contributing to potent stimulation of pancreatic β-cell autophagy. J Biol Chem 2018; 294:1218-1229. [PMID: 30518550 DOI: 10.1074/jbc.ra118.004833] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2018] [Revised: 11/19/2018] [Indexed: 12/12/2022] Open
Abstract
Autophagy is critical for maintaining cellular function via clearance of excess nutrients and damaged organelles. In pancreatic β-cells, it helps counter the endoplasmic reticulum (ER) stress that impairs insulin secretory capacity during Type 2 diabetes. Chronic exposure of β-cells to saturated fatty acids (FAs) such as palmitate stimulates ER stress and modulates autophagy, but the effects of unsaturated FAs such as oleate, which are also elevated during obesity, are less well understood. We therefore treated MIN6 cells and mouse islets for 8-48 h with either palmitate or oleate, and then monitored autophagic flux, signaling pathways, lysosomal biology, and phospholipid profiles. Compared with palmitate, oleate more effectively stimulated both autophagic flux and clearance of autophagosomes. The flux stimulation occurred independently of ER stress, nutrient-sensing (mTOR) and signaling pathways (protein kinases A, C, and D). Instead the mechanism involved the exchange factor directly activated by cAMP 2 (EPAC2). Oleate reduced cellular cAMP, and its effects on autophagic flux were reproduced or inhibited, respectively, by Epac2 knockdown or activation. Oleate also increased lysosomal acidity and increased phospholipid saturation, consistent with improved autophagosomal fusion with lysosomes. We conclude that a potent stimulation of autophagy might help explain the known benefits of unsaturated FAs in countering the toxicity of saturated FAs in β-cells during obesity and lipid loading.
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Affiliation(s)
- Kwan Yi Chu
- Division of Diabetes and Metabolism, Garvan Institute of Medical Research, 384 Victoria Street, Darlinghurst, NSW 2010; St. Vincent's Clinical School, Faculty of Medicine, UNSW Sydney, NSW 2052
| | - Liam O'Reilly
- Division of Diabetes and Metabolism, Garvan Institute of Medical Research, 384 Victoria Street, Darlinghurst, NSW 2010
| | - Natalie Mellet
- Baker IDI Heart and Diabetes Institute, Prahran, Victoria 3004, Australia
| | - Peter J Meikle
- Baker IDI Heart and Diabetes Institute, Prahran, Victoria 3004, Australia
| | - Clarissa Bartley
- Division of Diabetes and Metabolism, Garvan Institute of Medical Research, 384 Victoria Street, Darlinghurst, NSW 2010
| | - Trevor J Biden
- Division of Diabetes and Metabolism, Garvan Institute of Medical Research, 384 Victoria Street, Darlinghurst, NSW 2010; St. Vincent's Clinical School, Faculty of Medicine, UNSW Sydney, NSW 2052.
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170
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Pandey VK, Mathur A, Kakkar P. Emerging role of Unfolded Protein Response (UPR) mediated proteotoxic apoptosis in diabetes. Life Sci 2018; 216:246-258. [PMID: 30471281 DOI: 10.1016/j.lfs.2018.11.041] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2018] [Revised: 11/16/2018] [Accepted: 11/19/2018] [Indexed: 02/07/2023]
Abstract
Endoplasmic reticulum (ER) is a crucial single membrane organelle that acts as a quality control system for cellular proteins as it is intricately involved in their synthesis, folding and trafficking to the respective targets. Type 2 diabetes is characterized by enhanced blood glucose level that promotes insulin resistance and hampers cellular glucose metabolism. Hyperglycemia provokes mitochondrial ROS production and glycation of proteins which exert a tremendous load on ER for conventional refolding of misfolded/unfolded and nascent proteins that perturb ER homeostasis resulting in apoptotic cell death. Impairment in ER functions is suspected to be through specific ER membrane-bound proteins known as Unfolded Protein Response (UPR) sensor proteins. Conformational changes in these proteins induce oligomerization and cross-autophosphorylation which facilitate processes required for the restoration of ER homeostatic imbalance. Multiple studies have reported the involvement of UPR mediated autophagy and apoptotic pathways in the progression of metabolic disorders including diabetes, cardiac ischemia/reperfusion injury and hypoxia-mediated cell death. In this review, the involvement of UPR pathways in the progression of diabetes associated complications have been addressed, which underscores molecular crosstalks during neuropathy, nephropathy, hepatic injury and retinopathy. A better understanding of these molecular interventions may reveal advanced therapeutic approaches for preventing diabetic comorbidities. The article also highlights the importance of phytochemicals that are emerging as novel ER stress inhibitors and are being explored for targeted interaction in preventing cell death responses during diabetes.
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Affiliation(s)
- Vivek Kumar Pandey
- Herbal Research Laboratory, Food, Drug & Chemical Toxicology Group, CSIR-Indian Institute of Toxicology Research (CSIR-IITR), Vishvigyan Bhavan 31, M.G Marg, Lucknow 226001, Uttar Pradesh, India; Academy of Scientific and Innovative Research (AcSIR), CSIR-Indian Institute of Toxicology Research, Lucknow 226001, Uttar Pradesh, India
| | - Alpana Mathur
- Herbal Research Laboratory, Food, Drug & Chemical Toxicology Group, CSIR-Indian Institute of Toxicology Research (CSIR-IITR), Vishvigyan Bhavan 31, M.G Marg, Lucknow 226001, Uttar Pradesh, India; Babu Banarasi Das University, Lucknow, Uttar Pradesh, India
| | - Poonam Kakkar
- Herbal Research Laboratory, Food, Drug & Chemical Toxicology Group, CSIR-Indian Institute of Toxicology Research (CSIR-IITR), Vishvigyan Bhavan 31, M.G Marg, Lucknow 226001, Uttar Pradesh, India; Academy of Scientific and Innovative Research (AcSIR), CSIR-Indian Institute of Toxicology Research, Lucknow 226001, Uttar Pradesh, India.
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171
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Danilova T, Lindahl M. Emerging Roles for Mesencephalic Astrocyte-Derived Neurotrophic Factor (MANF) in Pancreatic Beta Cells and Diabetes. Front Physiol 2018; 9:1457. [PMID: 30386256 PMCID: PMC6198132 DOI: 10.3389/fphys.2018.01457] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Accepted: 09/26/2018] [Indexed: 12/31/2022] Open
Abstract
Mesencephalic astrocyte-derived neurotrophic factor (MANF) was originally identified as a secreted trophic factor for dopamine neurons in vitro. It protects and restores damaged cells in rodent models of Parkinson's disease, brain and heart ischemia, spinocerebellar ataxia and retina in vivo. However, its exact mechanism of action is not known. MANF is widely expressed in most human and mouse organs with high levels in secretory tissues. Intracellularly, MANF localizes to the endoplasmic reticulum (ER) and ER stress increases it's expression in cells and tissues. Furthermore, increased MANF levels has been detected in the sera of young children with newly diagnosed Type 1 (T1D) diabetes and Type 2 (T2D) diabetic patients. ER stress is caused by the accumulation of misfolded and aggregated proteins in the ER. It activates a cellular defense mechanism, the unfolded protein response (UPR), a signaling cascade trying to restore ER homeostasis. However, if prolonged, unresolved ER stress leads to apoptosis. Unresolved ER stress contributes to the progressive death of pancreatic insulin-producing beta cells in both T1D and T2D. Diabetes mellitus is characterized by hyperglycemia, caused by the inability of the beta cells to maintain sufficient levels of circulating insulin. The current medications, insulin and antidiabetic drugs, alleviate diabetic symptoms but cannot reconstitute physiological insulin secretion which increases the risk of devastating vascular complications of the disease. Thus, one of the main strategies in improving current diabetes therapy is to define and validate novel approaches to protect beta cells from stress as well as activate their regeneration. Embryonic deletion of the Manf gene in mice led to gradual postnatal development of insulin-deficient diabetes caused by reduced beta cell proliferation and increased beta cell death due to increased and sustained ER stress. In vitro, recombinant MANF partly protected mouse and human beta cells from ER stress-induced beta cell death and potentiated mouse and human beta cell proliferation. Importantly, in vivo overexpression of MANF in the pancreas of T1D mice led to increased beta cell proliferation and decreased beta cell death, suggesting that MANF could be a new therapeutic candidate for beta cell protection and regeneration in diabetes.
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Affiliation(s)
- Tatiana Danilova
- Institute of Biotechnology, HiLIFE, University of Helsinki, Helsinki, Finland
| | - Maria Lindahl
- Institute of Biotechnology, HiLIFE, University of Helsinki, Helsinki, Finland
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172
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Taylor R, Al-Mrabeh A, Zhyzhneuskaya S, Peters C, Barnes AC, Aribisala BS, Hollingsworth KG, Mathers JC, Sattar N, Lean MEJ. Remission of Human Type 2 Diabetes Requires Decrease in Liver and Pancreas Fat Content but Is Dependent upon Capacity for β Cell Recovery. Cell Metab 2018; 28:547-556.e3. [PMID: 30078554 DOI: 10.1016/j.cmet.2018.07.003] [Citation(s) in RCA: 240] [Impact Index Per Article: 40.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/13/2018] [Revised: 06/12/2018] [Accepted: 07/06/2018] [Indexed: 01/03/2023]
Abstract
The Diabetes Remission Clinical Trial reported return and persistence of non-diabetic blood glucose control in 46% of people with type 2 diabetes of up to 6 years duration. Detailed metabolic studies were performed on a subgroup (intervention, n = 64; control, n = 26). In the intervention group, liver fat content decreased (16.0% ± 1.3% to 3.1% ± 0.5%, p < 0.0001) immediately after weight loss. Similarly, plasma triglyceride and pancreas fat content decreased whether or not glucose control normalized. Recovery of first-phase insulin response (0.04[-0.05-0.32] to 0.11[0.0005-0.51] nmol/min/m2, p < 0.0001) defined those who returned to non-diabetic glucose control and this was durable at 12 months (0.11[0.005-0.81] nmol/min/m2, p = 0.0001). Responders were similar to non-responders at baseline but had shorter diabetes duration (2.7 ± 0.3 versus 3.8 ± 0.4 years; p = 0.02). This study demonstrates that β cell ability to recover long-term function persists after diagnosis, changing the previous paradigm of irreversible loss of β cell function in type 2 diabetes.
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Affiliation(s)
- Roy Taylor
- Newcastle Magnetic Resonance Centre, Institute of Cellular Medicine, Newcastle University, Campus for Ageing & Vitality, Newcastle upon Tyne NE4 5PL, UK.
| | - Ahmad Al-Mrabeh
- Newcastle Magnetic Resonance Centre, Institute of Cellular Medicine, Newcastle University, Campus for Ageing & Vitality, Newcastle upon Tyne NE4 5PL, UK
| | - Sviatlana Zhyzhneuskaya
- Newcastle Magnetic Resonance Centre, Institute of Cellular Medicine, Newcastle University, Campus for Ageing & Vitality, Newcastle upon Tyne NE4 5PL, UK
| | - Carl Peters
- Newcastle Magnetic Resonance Centre, Institute of Cellular Medicine, Newcastle University, Campus for Ageing & Vitality, Newcastle upon Tyne NE4 5PL, UK
| | - Alison C Barnes
- Human Nutrition Research Centre, Institute of Health & Society, Newcastle University, Newcastle upon Tyne NE2 4HH, UK
| | - Benjamin S Aribisala
- Department of Computer Science, Lagos State University, Ojo, Lagos State, Nigeria
| | - Kieren G Hollingsworth
- Newcastle Magnetic Resonance Centre, Institute of Cellular Medicine, Newcastle University, Campus for Ageing & Vitality, Newcastle upon Tyne NE4 5PL, UK
| | - John C Mathers
- Human Nutrition Research Centre, Institute of Cellular Medicine, Newcastle University, Newcastle upon Tyne NE2 4HH, UK
| | - Naveed Sattar
- Institute of Cardiovascular and Medical Science, University of Glasgow, Glasgow G12 8TA, UK
| | - Michael E J Lean
- Human Nutrition, School of Medicine, Dentistry and Nursing, College of Medical, Veterinary & Life Sciences, University of Glasgow, Glasgow G31 2ER, UK
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173
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Vitamin D inhibits palmitate-induced macrophage pro-inflammatory cytokine production by targeting the MAPK pathway. Immunol Lett 2018; 202:23-30. [DOI: 10.1016/j.imlet.2018.07.009] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2018] [Revised: 07/24/2018] [Accepted: 07/31/2018] [Indexed: 02/05/2023]
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174
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Iizuka Y, Kim H, Hirako S, Chiba K, Wada M, Matsumoto A. Benefits of combination low-dose pioglitazone plus fish oil on aged type 2 diabetes mice. J Food Drug Anal 2018; 26:1265-1274. [PMID: 30249325 PMCID: PMC9298570 DOI: 10.1016/j.jfda.2018.05.008] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2017] [Revised: 05/18/2018] [Accepted: 05/25/2018] [Indexed: 01/05/2023] Open
Abstract
The elderly patients with type 2 diabetes suffer more adverse drug events than young adults due to pharmacokinetic and pharmacodynamic changes associated with aging. Reducing the risks of these medication-related problems are equally important for the clinical care of older type 2 diabetes patients. Pioglitazone is used for treating type 2 diabetes as an oral antidiabetic drug. Despite pioglitazone is used helpful insulin sensitizers, the accumulation of subcutaneous fat is considered a major adverse effect of pioglitazone therapy. We investigated to reduce the adverse effect of pioglitazone by combination with fish oil rich in eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) in aged diabetic KK mice. The accumulation of subcutaneous fat associated with high-dose pioglitazone is reduced by fish oil, suppressing lipogenesis and stimulating fatty acid β-oxidation in the liver. Our data suggest that adding fish oil to low-dose pioglitazone results in anti-diabetic efficacy similar to that of the high-dose without concomitant body weight gain.
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175
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Costes S. Targeting protein misfolding to protect pancreatic beta-cells in type 2 diabetes. Curr Opin Pharmacol 2018; 43:104-110. [PMID: 30245473 DOI: 10.1016/j.coph.2018.08.016] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2018] [Revised: 07/30/2018] [Accepted: 08/17/2018] [Indexed: 02/06/2023]
Abstract
The islet in type 2 diabetes is characterized by beta-cell dysfunction and deficit, increased beta-cell apoptosis and amyloid deposits that derived from islet amyloid polypeptide (IAPP). In species such as humans that are vulnerable to developing type 2 diabetes, IAPP has the propensity to form toxic oligomers that contribute to beta-cell dysfunction and apoptosis, defining type 2 diabetes as a protein misfolding disorder. In this report, we review mechanisms known to contribute to protein misfolding and formation of toxic oligomers, and the deleterious consequences of these oligomers on beta-cell function and survival. Finally, we will consider approaches to prevent protein misfolding and formation of toxic oligomers as potential novel therapeutic targets for type 2 diabetes and other protein misfolding diseases.
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Affiliation(s)
- Safia Costes
- IGF, CNRS, INSERM, University of Montpellier, Montpellier, France.
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176
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Kalpana K, Priyadarshini E, Sreeja S, Jagan K, Anuradha CV. Scopoletin intervention in pancreatic endoplasmic reticulum stress induced by lipotoxicity. Cell Stress Chaperones 2018; 23:857-869. [PMID: 29574508 PMCID: PMC6111101 DOI: 10.1007/s12192-018-0893-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2018] [Revised: 03/03/2018] [Accepted: 03/12/2018] [Indexed: 12/29/2022] Open
Abstract
Endoplasmic reticulum (ER), a dynamic organelle, plays an essential role in organizing the signaling pathways involved in cellular adaptation, resilience, and survival. Impairment in the functions of ER occurs in a variety of nutritive disorders including obesity and type 2 diabetes. Here, we hypothesize that (scopoletin) SPL, a coumarin, has the potential to alleviate ER stress induced in vitro and in vivo models by lipotoxicity. To test this hypothesis, the ability of SPL to restore the levels of proteins of ER stress was analyzed. Rat insulinoma 5f (RIN5f) cells and Sprague Dawley rats were the models used for this study. Groups of control and high-fat, high-fructose diet (HFFD)-fed rats were treated with either SPL or 4-phenylbutyric acid. Status of ER stress was enumerated by quantitative RT-PCR, Western blot, electron microscopic, and immunohistochemical studies. Proximal proteins of ER stress inositol requiring enzyme 1 (IRE1), protein kinase like endoplasmic reticulum kinase (PERK), and activating transcription factor 6 (ATF6) were reduced in the β-cells by SPL. The subsequent signaling proteins X-box binding protein 1, eukaryotic initiation factor2α, activating transcription factor 4, and C/EBP homologous protein were also suppressed in their expression levels when treated with SPL. IRE1, PERK signaling leads to c-Jun-N-terminal kinases phosphorylation, a kinase that interrupts insulin signaling, which was also reverted upon scopoletin treatment. Finally, we confirm that SPL has the ability to suppress the stress proteins and limit pancreatic ER stress which might help in delaying the progression of insulin resistance.
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Affiliation(s)
- Kalaivanan Kalpana
- Department of Biochemistry and Biotechnology, Annamalai University, Annamalai Nagar, Tamil Nadu, 608002, India
| | - Emayavaramban Priyadarshini
- Department of Biochemistry and Biotechnology, Annamalai University, Annamalai Nagar, Tamil Nadu, 608002, India
| | - S Sreeja
- Department of Biochemistry and Biotechnology, Annamalai University, Annamalai Nagar, Tamil Nadu, 608002, India
| | - Kalivarathan Jagan
- Department of Biochemistry and Biotechnology, Annamalai University, Annamalai Nagar, Tamil Nadu, 608002, India
| | - Carani Venkatraman Anuradha
- Department of Biochemistry and Biotechnology, Annamalai University, Annamalai Nagar, Tamil Nadu, 608002, India.
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177
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Zhong L, Tran T, Baguley TD, Lee SJ, Henke A, To A, Li S, Yu S, Grieco FA, Roland J, Schultz PG, Eizirik DL, Rogers N, Chartterjee AK, Tremblay MS, Shen W. A novel inhibitor of inducible NOS dimerization protects against cytokine-induced rat beta cell dysfunction. Br J Pharmacol 2018; 175:3470-3485. [PMID: 29888783 PMCID: PMC6086989 DOI: 10.1111/bph.14388] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2017] [Revised: 05/14/2018] [Accepted: 05/28/2018] [Indexed: 12/23/2022] Open
Abstract
BACKGROUND AND PURPOSE Beta cell apoptosis is a major feature of type 1 diabetes, and pro-inflammatory cytokines are key drivers of the deterioration of beta cell mass through induction of apoptosis. Mitochondrial stress plays a critical role in mediating apoptosis by releasing cytochrome C into the cytoplasm, directly activating caspase-9 and its downstream signalling cascade. We aimed to identify new compounds that protect beta cells from cytokine-induced activation of the intrinsic (mitochondrial) pathway of apoptosis. EXPERIMENTAL APPROACH Diabetogenic media, composed of IL-1β, IFN-γ and high glucose, were used to induce mitochondrial stress in rat insulin-producing INS1E cells, and a high-content image-based screen of small molecule modulators of Casp9 pathway was performed. KEY RESULTS A novel small molecule, ATV399, was identified from a high-content image-based screen for compounds that inhibit cleaved caspase-9 activation and subsequent beta cell apoptosis induced by a combination of IL-1β, IFN-γ and high glucose, which together mimic the pathogenic diabetic milieu. Through medicinal chemistry optimization, potency was markedly improved (6-30 fold), with reduced inhibitory effects on CYP3A4. Improved analogues, such as CAT639, improved beta cell viability and insulin secretion in cytokine-treated rat insulin-producing INS1E cells and primary dispersed islet cells. Mechanistically, CAT639 reduced the production of NO by allosterically inhibiting dimerization of inducible NOS (iNOS) without affecting its mRNA levels. CONCLUSION AND IMPLICATIONS Taken together, these studies demonstrate a successful phenotypic screening campaign resulting in identification of an inhibitor of iNOS dimerization that protects beta cell viability and function through modulation of mitochondrial stress induced by cytokines.
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Affiliation(s)
- Linlin Zhong
- California Institute for Biomedical Research (Calibr)La JollaCA92037USA
| | - Tuan Tran
- California Institute for Biomedical Research (Calibr)La JollaCA92037USA
| | - Tyler D Baguley
- California Institute for Biomedical Research (Calibr)La JollaCA92037USA
| | - Sang Jun Lee
- California Institute for Biomedical Research (Calibr)La JollaCA92037USA
| | - Adam Henke
- California Institute for Biomedical Research (Calibr)La JollaCA92037USA
| | - Andrew To
- California Institute for Biomedical Research (Calibr)La JollaCA92037USA
| | - Sijia Li
- California Institute for Biomedical Research (Calibr)La JollaCA92037USA
| | - Shan Yu
- California Institute for Biomedical Research (Calibr)La JollaCA92037USA
| | - Fabio A Grieco
- ULB Center for Diabetes ResearchUniversite´ Libre de Bruxelles (ULB)Brussels1070Belgium
| | - Jason Roland
- California Institute for Biomedical Research (Calibr)La JollaCA92037USA
| | - Peter G Schultz
- California Institute for Biomedical Research (Calibr)La JollaCA92037USA
- Department of ChemistryThe Scripps Research InstituteLa JollaCA92037USA
| | - Decio L Eizirik
- ULB Center for Diabetes ResearchUniversite´ Libre de Bruxelles (ULB)Brussels1070Belgium
| | - Nikki Rogers
- California Institute for Biomedical Research (Calibr)La JollaCA92037USA
| | | | | | - Weijun Shen
- California Institute for Biomedical Research (Calibr)La JollaCA92037USA
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178
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Riahi Y, Israeli T, Cerasi E, Leibowitz G. Effects of proinsulin misfolding on β-cell dynamics, differentiation and function in diabetes. Diabetes Obes Metab 2018; 20 Suppl 2:95-103. [PMID: 30230182 DOI: 10.1111/dom.13379] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/25/2018] [Revised: 05/17/2018] [Accepted: 05/23/2018] [Indexed: 12/12/2022]
Abstract
ER stress due to proinsulin misfolding has an important role in the pathophysiology of rare forms of permanent neonatal diabetes (PNDM) and probably also of common type 1 (T1D) and type 2 diabetes (T2D). Accumulation of misfolded proinsulin in the ER stimulates the unfolded protein response (UPR) that may eventually lead to apoptosis through a process called the terminal UPR. However, the β-cell ER has an incredible ability to cope with accumulation of misfolded proteins; therefore, it is not clear whether in common forms of diabetes the accumulation of misfolded proinsulin exceeds the point of no return in which terminal UPR is activated. Many studies showed that the UPR is altered in both T1D and T2D; however, the observed changes in the expression of different UPR markers are inconsistent and it is not clear whether they reflect an adaptive response to stress or indeed mediate the β-cell dysfunction of diabetes. Herein, we critically review the literature on the effects of proinsulin misfolding and ER stress on β-cell dysfunction and loss in diabetes with emphasis on β-cell dynamics, and discuss the gaps in understanding the role of proinsulin misfolding in the pathophysiology of diabetes.
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Affiliation(s)
- Yael Riahi
- The Diabetes Unit and the Endocrine Service, Hadassah-Hebrew University Medical Center, Jerusalem, Israel
| | - Tal Israeli
- The Diabetes Unit and the Endocrine Service, Hadassah-Hebrew University Medical Center, Jerusalem, Israel
| | - Erol Cerasi
- The Diabetes Unit and the Endocrine Service, Hadassah-Hebrew University Medical Center, Jerusalem, Israel
| | - Gil Leibowitz
- The Diabetes Unit and the Endocrine Service, Hadassah-Hebrew University Medical Center, Jerusalem, Israel
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179
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Wu X, Li Z, Chen K, Yin P, Zheng L, Sun S, Chen X. Egr-1 transactivates WNT5A gene expression to inhibit glucose-induced β-cell proliferation. BIOCHIMICA ET BIOPHYSICA ACTA. GENE REGULATORY MECHANISMS 2018; 1861:S1874-9399(18)30218-9. [PMID: 30025875 DOI: 10.1016/j.bbagrm.2018.07.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/20/2018] [Revised: 07/10/2018] [Accepted: 07/13/2018] [Indexed: 02/07/2023]
Abstract
Selective β-cell loss is a characteristic of type 2 diabetes mellitus (T2DM). Inhibition of glucose-stimulated β-cell proliferation is one of the in vivo results of the lipotoxicity of saturated fatty acids (SFAs). However, the mechanism by which lipotoxicity inhibits β-cell proliferation is still unclear. In this study, we found palmitate, a saturated fatty acid, inhibited the β-cell proliferation induced by high glucose through the induction of Wnt5a expression in vitro and in vivo. We also found that Wnt5a was both sufficient and necessary for inhibition of β-cell proliferation. Additionally, Egr-1, but not NF-κB, FOXO1, Smad2, Smad3, SP1 or SP3 mediated the expression of Wnt5a. Deletion and site-directed mutagenesis of the WNT5A promoter revealed that activation of WNT5A gene transcription depends primarily on a putative Egr-binding sequence between nucleotides -52 to -44, upstream of the transcription start site. Furthermore, Egr-1 bound directly to this sequence in response to palmitate treatment, both in vitro and in vivo. Moreover, after mice islets were treated with Egr inhibitors, the expression of Wnt5a decreased significantly and the glucose-induced β-cell proliferation inhibited by palmitate was resumed. These findings establish Wnt5a as an Egr-1 target gene in β-cells, uncovering a novel Egr-1/Wnt5a pathway by which saturated free fatty acids block glucose-induced β-cell proliferation. Our study lends support for the potential of Egr-1 inhibitors or Wnt5a antibodies as therapeutics for the treatment of T2DM.
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Affiliation(s)
- XingEr Wu
- The Molecular Diagnostic Center, Zhongshan City People's Hospital, Zhongshan 528403, Guangdong, China; Department of Laboratory Medicine, Nanfang Hospital, Southern Medical University, Guangzhou 510515, Guangdong, China
| | - ZeHong Li
- Guzhen Sub-bureau, Zhongshan Public Security Bureau, Zhongshan 528400, Guangdong, China
| | - Kang Chen
- Zhongshan City People's Hospital, Zhongshan 528403, Guangdong, China
| | - PeiHong Yin
- Zhongshan City People's Hospital, Zhongshan 528403, Guangdong, China
| | - Lei Zheng
- Department of Laboratory Medicine, Nanfang Hospital, Southern Medical University, Guangzhou 510515, Guangdong, China.
| | - ShiJun Sun
- The Molecular Diagnostic Center, Zhongshan City People's Hospital, Zhongshan 528403, Guangdong, China.
| | - XiaoYu Chen
- The Eighth Affiliated Hospital of Sun Yat-Sen University, Futian, 518000 Shenzhen, China.
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180
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Kefalas G, Jouvet N, Baldwin C, Estall JL, Larose L. Peptide-based sequestration of the adaptor protein Nck1 in pancreatic β cells enhances insulin biogenesis and protects against diabetogenic stresses. J Biol Chem 2018; 293:12516-12524. [PMID: 29941454 DOI: 10.1074/jbc.ra118.002728] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2018] [Revised: 06/16/2018] [Indexed: 01/14/2023] Open
Abstract
One feature of diabetes is the failure of pancreatic β cells to produce insulin, but the molecular mechanisms leading to this failure remain unclear. Increasing evidence supports a role for protein kinase R-like endoplasmic reticulum kinase (PERK) in the development and function of healthy pancreatic β cells. Previously, our group identified the adaptor protein Nck1 as a negative regulator of PERK. Indeed, we demonstrated that Nck1, by directly binding PERK autophosphorylated on Tyr561, limits PERK activation and signaling. Accordingly, we found that stable depletion of Nck1 in β cells promotes PERK activation and signaling, increases insulin biosynthesis, and improves cell viability in response to diabetes-related stresses. Herein, we explored the therapeutic potential of abrogating the interaction between Nck and PERK to improve β-cell function and survival. To do so, we designed and used a peptide containing the minimal PERK sequence involved in binding Nck1 conjugated to the cell-permeable protein transduction domain from the HIV protein TAT. In the current study, we confirm that the synthetic TAT-Tyr(P)561 phosphopeptide specifically binds the SH2 domain of Nck and prevents Nck interaction with PERK, thereby promoting basal PERK activation. Moreover, we report that treatment of β cells with TAT-Tyr(P)561 inhibits glucolipotoxicity-induced apoptosis, whereas it enhances insulin production and secretion. Taken together, our results support the potential of sequestering Nck using a synthetic peptide to enhance basal PERK activation and create more robust β cells.
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Affiliation(s)
- George Kefalas
- From the Research Institute of the McGill University Health Centre, Montreal, Quebec H4A 3J1, Canada.,the Division of Experimental Medicine, Department of Medicine, McGill University, Montreal, Quebec H4A 3J1, Canada, and
| | - Nathalie Jouvet
- the Institut de Recherches Cliniques de Montreal, Montreal, Quebec H2W 1R7, Canada
| | - Cindy Baldwin
- From the Research Institute of the McGill University Health Centre, Montreal, Quebec H4A 3J1, Canada.,the Institut de Recherches Cliniques de Montreal, Montreal, Quebec H2W 1R7, Canada
| | - Jennifer L Estall
- the Division of Experimental Medicine, Department of Medicine, McGill University, Montreal, Quebec H4A 3J1, Canada, and .,the Institut de Recherches Cliniques de Montreal, Montreal, Quebec H2W 1R7, Canada
| | - Louise Larose
- From the Research Institute of the McGill University Health Centre, Montreal, Quebec H4A 3J1, Canada, .,the Division of Experimental Medicine, Department of Medicine, McGill University, Montreal, Quebec H4A 3J1, Canada, and
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181
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Jiang D, Wan F. Exendin-4 protects INS-1 cells against palmitate-induced apoptosis through the IRE1α-Xbp1 signaling pathway. Exp Ther Med 2018; 16:1029-1035. [PMID: 30112049 DOI: 10.3892/etm.2018.6240] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2017] [Accepted: 05/24/2018] [Indexed: 12/16/2022] Open
Abstract
The anti-apoptotic effect of the incretin analog, exendin-4 (EX-4) on pancreatic β cells is mediated via the activation of protein kinase B (Akt) signaling, and its effect is partly produced through the inhibition of endoplasmic reticulum (ER) stress. However, the molecular mechanisms that underlie the effect of EX-4 on the suppression of ER stress and the upregulation of Akt signaling are poorly understood. Inositol-requiring enzyme 1 (IRE1), a member of the ER-localized transmembrane protein family, activates its downstream transcription factor X-box binding protein 1 (XBP1) to mediate a key part of the cellular unfolded protein response in order to cope with ER stress. Using the clonal rat pancreatic β cell line INS-1, the present study produced an in vitro model of ER stress using palmitate (PA) in order to determine whether the beneficial effect of EX-4 under ER stress was regulated by the IRE1α-Xbp1 signaling pathway. The results demonstrated that the reduction in ER stress and the activation Akt by EX-4 may be associated with the upregulation of IRE1α phosphorylation and the splicing of Xbp1 mRNA, which improved PA-reduced cell viability. This effect was partially abrogated by the knockdown of IRE1α with small interfering RNA. Additionally, cellular IRE1α was phosphorylated by the protein kinase A (PKA) associated with EX-4 and the activation of IRE1α, as IRE1α phosphorylation was attenuated by the inhibition of PKA with its inhibitor. In conclusion, the data identified the IRE1α-Xbp1 signaling pathway as an essential mediator that associates EX-4 with the intracellular mechanism that inhibits ER stress and activates Akt in order to regulate β cell survival. This may provide important evidence for the use of EX-4 in treatments for type 2 diabetes.
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Affiliation(s)
- Dongdong Jiang
- Department of Endocrinology and Metabolism, Huashan Hospital, Shanghai Medical College, Fudan University, Shanghai 200040, P.R. China
| | - Fang Wan
- Department of Orthopedic Sports Medicine, Huashan Hospital, Fudan University, Shanghai 200040, P.R. China
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182
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Palmitate and insulin counteract glucose-induced thioredoxin interacting protein (TXNIP) expression in insulin secreting cells via distinct mechanisms. PLoS One 2018; 13:e0198016. [PMID: 29813102 PMCID: PMC5973613 DOI: 10.1371/journal.pone.0198016] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2017] [Accepted: 05/12/2018] [Indexed: 01/20/2023] Open
Abstract
Glucose and palmitate synergistically stimulate insulin secretion, but chronically elevated they induce apoptotic β-cell death. The glucotoxic effect has been attributed, at least partly, to the upregulation of the oxidative stress marker thioredoxin interacting protein (TXNIP). Palmitate downregulates TXNIP expression, the functional significance of which is still under debate. This study examines the mechanism and consequence of palmitate-mediated TXNIP regulation in insulin secreting cells. Palmitate (600 μM) reduced TXNIP mRNA levels in isolated human and mouse islets independently of FFAR1/GPR40. Similar effects of palmitate were observed in INS-1E cells and mimicked by other long chain fatty acids. The lowering of TXNIP mRNA was significant already 1 h after addition of palmitate, persisted for 24 h and was directly translated to changes in TXNIP protein. The pharmacological inhibition of palmitate-induced phosphorylation of AMPK, ERK1/2, JNK and PKCα/β by BML-275, PD98059, SP600125 and Gö6976, respectively, did not abolish palmitate-mediated TXNIP downregulation. The effect of palmitate was superimposed by a time-dependent (8 h and 24 h) decline of TXNIP mRNA and protein. This decline correlated with accumulation of secreted insulin into the medium. Accordingly, exogenously added insulin reduced TXNIP mRNA and protein levels, an effect counteracted by the insulin/IGF-1 receptor antagonist linsitinib. The inhibition of PI3K and Akt/PKB increased TXNIP mRNA levels. The histone deacetylase (HDAC1/2/3) inhibitor MS-275 completely abrogated the time-dependent, insulin-mediated reduction of TXNIP, leaving the effect of palmitate unaltered. Acute stimulation of insulin secretion and chronic accentuation of cell death by palmitate occurred independently of TXNIP regulation. On the contrary, palmitate antagonized glucose-augmented ROS production. In conclusion, glucose-induced TXNIP expression is efficiently antagonized by two independent mechanisms, namely via an autocrine activation of insulin/IGF-1 receptors involving HDAC and by palmitate attenuating oxidative stress of β-cells.
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183
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Ruiz L, Gurlo T, Ravier MA, Wojtusciszyn A, Mathieu J, Brown MR, Broca C, Bertrand G, Butler PC, Matveyenko AV, Dalle S, Costes S. Proteasomal degradation of the histone acetyl transferase p300 contributes to beta-cell injury in a diabetes environment. Cell Death Dis 2018; 9:600. [PMID: 29789539 PMCID: PMC5964068 DOI: 10.1038/s41419-018-0603-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2017] [Revised: 03/09/2018] [Accepted: 04/17/2018] [Indexed: 12/25/2022]
Abstract
In type 2 diabetes, amyloid oligomers, chronic hyperglycemia, lipotoxicity, and pro-inflammatory cytokines are detrimental to beta-cells, causing apoptosis and impaired insulin secretion. The histone acetyl transferase p300, involved in remodeling of chromatin structure by epigenetic mechanisms, is a key ubiquitous activator of the transcriptional machinery. In this study, we report that loss of p300 acetyl transferase activity and expression leads to beta-cell apoptosis, and most importantly, that stress situations known to be associated with diabetes alter p300 levels and functional integrity. We found that proteasomal degradation is the mechanism subserving p300 loss in beta-cells exposed to hyperglycemia or pro-inflammatory cytokines. We also report that melatonin, a hormone produced in the pineal gland and known to play key roles in beta-cell health, preserves p300 levels altered by these toxic conditions. Collectively, these data imply an important role for p300 in the pathophysiology of diabetes.
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Affiliation(s)
- Lucie Ruiz
- IGF, CNRS, INSERM, University of Montpellier, Montpellier, France
| | - Tatyana Gurlo
- Larry L. Hillblom Islet Research Center, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, USA
| | - Magalie A Ravier
- IGF, CNRS, INSERM, University of Montpellier, Montpellier, France
| | - Anne Wojtusciszyn
- IGF, CNRS, INSERM, University of Montpellier, Montpellier, France.,Laboratory of Cell Therapy for Diabetes (LTCD), Institute for Regenerative Medicine and Biotherapy (IRMB), University Hospital of Montpellier, Montpellier, France.,Department of Endocrinology, Diabetes, and Nutrition, University Hospital of Montpellier, Montpellier, France
| | - Julia Mathieu
- IGF, CNRS, INSERM, University of Montpellier, Montpellier, France
| | - Matthew R Brown
- Department of Physiology and Biomedical Engineering, Mayo Clinic School of Medicine, Mayo Clinic, Rochester, MN, USA
| | - Christophe Broca
- Laboratory of Cell Therapy for Diabetes (LTCD), Institute for Regenerative Medicine and Biotherapy (IRMB), University Hospital of Montpellier, Montpellier, France
| | | | - Peter C Butler
- Larry L. Hillblom Islet Research Center, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, USA
| | - Aleksey V Matveyenko
- Department of Physiology and Biomedical Engineering, Mayo Clinic School of Medicine, Mayo Clinic, Rochester, MN, USA
| | - Stéphane Dalle
- IGF, CNRS, INSERM, University of Montpellier, Montpellier, France
| | - Safia Costes
- IGF, CNRS, INSERM, University of Montpellier, Montpellier, France.
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184
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Kulanuwat S, Tangjittipokin W, Jungtrakoon P, Chanprasert C, Sujjitjoon J, Binnima N, Yenchitsomanus PT, Plengvidhya N. DNAJC3 mutation in Thai familial type 2 diabetes mellitus. Int J Mol Med 2018; 42:1064-1073. [PMID: 29767246 DOI: 10.3892/ijmm.2018.3678] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2017] [Accepted: 05/08/2018] [Indexed: 11/05/2022] Open
Abstract
Type 2 diabetes mellitus (T2D) is a heterogeneous disease, with certain cases presenting an autosomal dominant type. The rare coding variants of disease‑causing genes in T2D remain mostly unclear. The present study aimed to identify the disease‑causing gene conducting whole exome sequencing in a Thai T2D family with an autosomal dominant transmission of T2D with no evidence of mutations in known maturity‑onset diabetes of the young (MODY) genes. Candidate variants were selected according to certain criteria of mutation prediction programs, followed by segregation analysis with diabetes in the family. The results demonstrated that, of the 68,817 variants obtained, 122 were considered as candidate variants subsequent to the filtering processes. Genotyping of these variants revealed that DnaJ homolog subfamily C member 3 (DNAJC3) p.H238N segregated with diabetes in the family. This mutation was also identified in another proband from the autosomal dominant T2D family without mutation in known MODY genes and was segregated with diabetes. This variant was also identified in 14/1,000 older‑onset T2D patients [minor allele frequency (MAF)=0.007], 2/500 non‑diabetic controls (MAF=0.002) and 3 prediabetic individuals who were previously classified as non‑diabetic controls. In silico mutagenesis and protein modeling of p.H238N revealed changes of the polar contacts across the tetratricopeptide repeat (TPR) motif and TPR subdomains, which may affect the protein tertiary structure. Furthermore, the expression of DNAJC3 H238N protein was 0.68±0.08 fold (P<0.05) lower when compared with that of the wild‑type, possibly due to protein instability. Thus, DNAJC3 p.H238N is likely to be a variant causing diabetes.
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Affiliation(s)
- Sirikul Kulanuwat
- Siriraj Center of Research Excellence for Diabetes and Obesity, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok 10700, Thailand
| | - Watip Tangjittipokin
- Siriraj Center of Research Excellence for Diabetes and Obesity, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok 10700, Thailand
| | - Prapaporn Jungtrakoon
- Siriraj Center of Research Excellence for Diabetes and Obesity, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok 10700, Thailand
| | - Chutima Chanprasert
- Siriraj Center of Research Excellence for Diabetes and Obesity, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok 10700, Thailand
| | - Jatuporn Sujjitjoon
- Siriraj Center of Research Excellence for Diabetes and Obesity, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok 10700, Thailand
| | - Ninareeman Binnima
- Siriraj Center of Research Excellence for Diabetes and Obesity, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok 10700, Thailand
| | - Pa-Thai Yenchitsomanus
- Siriraj Center of Research Excellence for Diabetes and Obesity, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok 10700, Thailand
| | - Nattachet Plengvidhya
- Siriraj Center of Research Excellence for Diabetes and Obesity, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok 10700, Thailand
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185
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Marasco MR, Linnemann AK. β-Cell Autophagy in Diabetes Pathogenesis. Endocrinology 2018; 159:2127-2141. [PMID: 29617763 PMCID: PMC5913620 DOI: 10.1210/en.2017-03273] [Citation(s) in RCA: 69] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/31/2017] [Accepted: 03/27/2018] [Indexed: 12/25/2022]
Abstract
Nearly 100 years have passed since Frederick Banting and Charles Best first discovered and purified insulin. Their discovery and subsequent improvements revolutionized the treatment of diabetes, and the field continues to move at an ever-faster pace with respect to unique treatments for both type 1 and type 2 diabetes. Despite these advances, we still do not fully understand how apoptosis of the insulin-producing β-cells is triggered, presenting a challenge in the development of preventative measures. In recent years, the process of autophagy has generated substantial interest in this realm due to discoveries highlighting its clear role in the maintenance of cellular homeostasis. As a result, the number of studies focused on islet and β-cell autophagy has increased substantially in recent years. In this review, we will discuss what is currently known regarding the role of β-cell autophagy in type 1 and type 2 diabetes pathogenesis, with an emphasis on new and exciting developments over the past 5 years. Further, we will discuss how these discoveries might be translated into unique treatments in the coming years.
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Affiliation(s)
- Michelle R Marasco
- Department of Pediatrics, Indiana University School of Medicine, Indianapolis, Indiana
| | - Amelia K Linnemann
- Department of Pediatrics, Indiana University School of Medicine, Indianapolis, Indiana
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, Indiana
- Department of Cellular and Integrative Physiology, Indiana University School of Medicine, Indianapolis, Indiana
- Center for Diabetes and Metabolic Diseases, Indiana University School of Medicine, Indianapolis, Indiana
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186
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Liquiritigenin prevents palmitate-induced beta-cell apoptosis via estrogen receptor-mediated AKT activation. Biomed Pharmacother 2018; 101:348-354. [DOI: 10.1016/j.biopha.2018.02.097] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2017] [Revised: 02/20/2018] [Accepted: 02/21/2018] [Indexed: 12/21/2022] Open
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187
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Hansson SF, Zhou AX, Vachet P, Eriksson JW, Pereira MJ, Skrtic S, Jongsma Wallin H, Ericsson-Dahlstrand A, Karlsson D, Ahnmark A, Sörhede Winzell M, Magnone MC, Davidsson P. Secretagogin is increased in plasma from type 2 diabetes patients and potentially reflects stress and islet dysfunction. PLoS One 2018; 13:e0196601. [PMID: 29702679 PMCID: PMC5922551 DOI: 10.1371/journal.pone.0196601] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2017] [Accepted: 04/16/2018] [Indexed: 01/09/2023] Open
Abstract
Beta cell dysfunction accompanies and drives the progression of type 2 diabetes mellitus (T2D), but there are few clinical biomarkers available to assess islet cell stress in humans. Secretagogin, a protein enriched in pancreatic islets, demonstrates protective effects on beta cell function in animals. However, its potential as a circulating biomarker released from human beta cells and islets has not been studied. In this study primary human islets, beta cells and plasma samples were used to explore secretion and expression of secretagogin in relation to the T2D pathology. Secretagogin was abundantly and specifically expressed and secreted from human islets. Furthermore, T2D patients had an elevated plasma level of secretagogin compared with matched healthy controls, which was confirmed in plasma of diabetic mice transplanted with human islets. Additionally, the plasma secretagogin level of the human cohort had an inverse correlation to clinical assessments of beta cell function. To explore the mechanism of secretagogin release in vitro, human beta cells (EndoC-βH1) were exposed to elevated glucose or cellular stress-inducing agents. Secretagogin was not released in parallel with glucose stimulated insulin release, but was markedly elevated in response to endoplasmic reticulum stressors and cytokines. These findings indicate that secretagogin is a potential novel biomarker, reflecting stress and islet cell dysfunction in T2D patients.
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Affiliation(s)
- Sara F. Hansson
- Translational Science, Cardiovascular, Renal and Metabolism, IMED Biotech Unit, AstraZeneca, Gothenburg, Sweden
- * E-mail:
| | - Alex-Xianghua Zhou
- Translational Science, Cardiovascular, Renal and Metabolism, IMED Biotech Unit, AstraZeneca, Gothenburg, Sweden
| | - Paulina Vachet
- Translational Science, Cardiovascular, Renal and Metabolism, IMED Biotech Unit, AstraZeneca, Gothenburg, Sweden
| | - Jan W. Eriksson
- Department of Medical Sciences, Clinical Diabetes and Metabolism, Uppsala University, Uppsala, Sweden
| | - Maria J. Pereira
- Department of Medical Sciences, Clinical Diabetes and Metabolism, Uppsala University, Uppsala, Sweden
| | - Stanko Skrtic
- Translational Medicine Unit CVRM, Early Clinical Development, IMED Biotech Unit, AstraZeneca, Gothenburg, Sweden
- Institute of Medicine at Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | | | | | - Daniel Karlsson
- Bioscience, Cardiovascular, Renal and Metabolism, IMED Biotech Unit, AstraZeneca, Gothenburg, Sweden
| | - Andrea Ahnmark
- Bioscience, Cardiovascular, Renal and Metabolism, IMED Biotech Unit, AstraZeneca, Gothenburg, Sweden
| | - Maria Sörhede Winzell
- Bioscience, Cardiovascular, Renal and Metabolism, IMED Biotech Unit, AstraZeneca, Gothenburg, Sweden
| | - Maria Chiara Magnone
- Translational Science, Cardiovascular, Renal and Metabolism, IMED Biotech Unit, AstraZeneca, Gothenburg, Sweden
| | - Pia Davidsson
- Translational Science, Cardiovascular, Renal and Metabolism, IMED Biotech Unit, AstraZeneca, Gothenburg, Sweden
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188
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Kim K, Chung MH, Park S, Cha J, Baek JH, Lee SY, Choi SY. ER stress attenuation by Aloe-derived polysaccharides in the protection of pancreatic β-cells from free fatty acid-induced lipotoxicity. Biochem Biophys Res Commun 2018; 500:797-803. [PMID: 29684344 DOI: 10.1016/j.bbrc.2018.04.162] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2018] [Accepted: 04/19/2018] [Indexed: 01/21/2023]
Abstract
Insulin resistance, a pathophysiology of type 2 diabetes, is associated with obesity. Lipotoxicity in obesity leads to the dysfunction and death of pancreatic β-cells and inadequate insulin production, thereby aggravating type 2 diabetes. The present study was conducted to determine the effect of Aloe vera polysaccharides (APs) as an anti-hyperglycemic agent and their mechanisms of action. Gel polysaccharides from Aloe extracts were separated using ultrafiltration devices with molecular weight-cutoff membranes, and the protective effect of APs on pancreatic β-cells in response to free fatty acids (FFAs) was determined. Hamster pancreatic β-cell line HIT-T15 was treated with palmitate and APs to analyze cellular responses. We observed a large number of apoptotic β-cell death after treatment with high levels of palmitate, but this was efficiently prevented by the addition of APs in a dose-dependent manner. It was found that the anti-apoptotic properties of APs were largely due to the relief of endoplasmic reticulum (ER) stress signaling. APs were effective in interfering with the FFA-induced activation of the PERK and IRE1 pathways as well as ROS generation, thereby protecting pancreatic β-cells from lipotoxicity. Although variation in the chain length of APs can influence the activity of FFA-mediated ER stress signaling in different ways, polysaccharide mixtures with molecular weights higher than 50 kDa showed greater antiapoptotic and antioxidant activity in β-cells. After oral administration of APs, markedly lowering fasting blood glucose levels were observed in db/db mice, providing evidence of the potential of APs as an alternative insulin sensitizer. Therefore, it was concluded that APs have a protective effect against type 2 diabetes by modulating obesity-induced ER stress in pancreatic β-cells.
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Affiliation(s)
- Kisoo Kim
- Department of Life Sciences, Korea University, Seoul, Republic of Korea
| | - Min Hwa Chung
- Department of Life Sciences, Korea University, Seoul, Republic of Korea
| | - Soyoung Park
- Department of Life Sciences, Korea University, Seoul, Republic of Korea
| | - Jimin Cha
- KJM Aloe R&D Center, Seoul, Republic of Korea
| | | | - Shin-Young Lee
- Department of Biotechnology, Kang Won Natuinal University, Chuncheon, Republic of Korea
| | - Sang-Yun Choi
- Department of Life Sciences, Korea University, Seoul, Republic of Korea.
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189
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Cation-Independent Mannose 6-Phosphate Receptor Deficiency Enhances β-Cell Susceptibility to Palmitate. Mol Cell Biol 2018; 38:MCB.00680-17. [PMID: 29378831 DOI: 10.1128/mcb.00680-17] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2017] [Accepted: 01/22/2018] [Indexed: 12/29/2022] Open
Abstract
Palmitate attenuates insulin secretion and reduces the viability of insulin-producing cells. Previous studies identified the aberrant palmitoylation or mispalmitoylation of proteins as one mechanism by which palmitate causes β-cell damage. In this report, we identify a role for lysosomal protein degradation as a mechanism by which β cells defend themselves against excess palmitate. The cation-independent mannose 6-phosphate receptor (CI-MPR) is responsible for the trafficking of mannose 6-phosphate-tagged proteins to lysosomes via Golgi sorting and from extracellular locations through endocytosis. RINm5F cells, which are highly sensitive to palmitate, lack CI-MPR. The reconstitution of CI-MPR expression attenuates the induction of endoplasmic reticulum (ER) stress and the toxic effects of palmitate on RINm5F cell viability. INS832/13 cells express CI-MPR and are resistant to the palmitate-mediated loss of cell viability. The reduction of CI-MPR expression increases the sensitivity of INS832/13 cells to the toxic effects of palmitate treatment. The inhibition of lysosomal acid hydrolase activity by weak base treatment of islets under glucolipotoxic conditions causes islet degeneration that is prevented by the inhibition of protein palmitoylation. These findings indicate that defects in lysosomal function lead to the enhanced sensitivity of insulin-producing cells to palmitate and support a role for normal lysosomal function in the protection of β cells from excess palmitate.
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190
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Neelankal John A, Jiang FX. An overview of type 2 diabetes and importance of vitamin D3-vitamin D receptor interaction in pancreatic β-cells. J Diabetes Complications 2018; 32:429-443. [PMID: 29422234 DOI: 10.1016/j.jdiacomp.2017.12.002] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/10/2017] [Revised: 12/03/2017] [Accepted: 12/07/2017] [Indexed: 02/07/2023]
Abstract
One significant health issue that plagues contemporary society is that of Type 2 diabetes (T2D). This disease is characterised by higher-than-average blood glucose levels as a result of a combination of insulin resistance and insufficient insulin secretions from the β-cells of pancreatic islets of Langerhans. Previous developmental research into the pancreas has identified how early precursor genes of pancreatic β-cells, such as Cpal, Ngn3, NeuroD, Ptf1a, and cMyc, play an essential role in the differentiation of these cells. Furthermore, β-cell molecular characterization has also revealed the specific role of β-cell-markers, such as Glut2, MafA, Ins1, Ins2, and Pdx1 in insulin expression. The expression of these genes appears to be suppressed in the T2D β-cells, along with the reappearance of the early endocrine marker genes. Glucose transporters transport glucose into β-cells, thereby controlling insulin release during hyperglycaemia. This stimulates glycolysis through rises in intracellular calcium (a process enhanced by vitamin D) (Norman et al., 1980), activating 2 of 4 proteinases. The rise in calcium activates half of pancreatic β-cell proinsulinases, thus releasing free insulin from granules. The synthesis of ATP from glucose by glycolysis, Krebs cycle and oxidative phosphorylation plays a role in insulin release. Some studies have found that the β-cells contain high levels of the vitamin D receptor; however, the role that this plays in maintaining the maturity of the β-cells remains unknown. Further research is required to develop a more in-depth understanding of the role VDR plays in β-cell function and the processes by which the beta cell function is preserved.
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Affiliation(s)
- Abraham Neelankal John
- Harry Perkins Institute of Medical Research, Centre for Medical Research, University of Western Australia, Nedlands, Western Australia, Australia; School of Medicine and Pharmacology, University of Western Australia, Carwley, Western Australia, Australia
| | - Fang-Xu Jiang
- Harry Perkins Institute of Medical Research, Centre for Medical Research, University of Western Australia, Nedlands, Western Australia, Australia; School of Medicine and Pharmacology, University of Western Australia, Carwley, Western Australia, Australia.
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191
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Zeng W, Tang J, Li H, Xu H, Lu H, Peng H, Lin C, Gao R, Lin S, Lin K, Liu K, Jiang Y, Weng J, Zeng L. Caveolin-1 deficiency protects pancreatic β cells against palmitate-induced dysfunction and apoptosis. Cell Signal 2018; 47:65-78. [PMID: 29596872 DOI: 10.1016/j.cellsig.2018.03.013] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2018] [Revised: 03/18/2018] [Accepted: 03/23/2018] [Indexed: 12/14/2022]
Abstract
Lipotoxicity leads to insulin secretion deficiency, which is among the important causes for the onset of type 2 diabetes mellitus. Thus, the restoration of β-cell mass and preservation of its endocrine function are long-sought goals in diabetes research. Previous studies have suggested that the membrane protein caveolin-1 (Cav-1) is implicated in β-cell apoptosis and insulin secretion, however, the underlying mechanisms still remains unclear. Our objective is to explore whether Cav-1 depletion protects pancreatic β cells from lipotoxicity and what are the underlying mechanisms. In this study, we found that Cav-1 silencing significantly promoted β-cell proliferation, inhibited palmitate (PA)-induced pancreatic β-cell apoptosis and enhanced insulin production and secretion. These effects were associated with enhanced activities of Akt and ERK1/2, which in turn downregulated the expression of cell cycle inhibitors (FOXO1, GSK3β, P21, P27 and P53) and upregulated the expression of Cyclin D2 and Cyclin D3. Subsequent inhibition of PI3K/Akt and ERK/MAPK pathways abolished Cav-1 depletion induced β-cell mass protection. Furthermore, under PA induced endoplasmic reticulum (ER) stress, Cav-1 silencing significantly reduced eIF2α phosphorylation and the expression of ER stress-responsive markers BiP and CHOP, which are among the known sensitizers of lipotoxicity. Our findings suggest Cav-1 as potential target molecule in T2DM treatment via the preservation of lipotoxicity-induced β-cell mass reduction and the attenuation of insulin secretion dysfunction.
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Affiliation(s)
- Wen Zeng
- Department of Endocrinology and Metabolism, The Third Affiliated Hospital of Sun Yat-Sen University, Guangdong Provincial Key Laboratory of Diabetology, Guangzhou 510630, China
| | - Jiansong Tang
- Department of Endocrinology and Metabolism, The Third Affiliated Hospital of Sun Yat-Sen University, Guangdong Provincial Key Laboratory of Diabetology, Guangzhou 510630, China
| | - Haicheng Li
- Department of Endocrinology and Metabolism, The Third Affiliated Hospital of Sun Yat-Sen University, Guangdong Provincial Key Laboratory of Diabetology, Guangzhou 510630, China
| | - Haixia Xu
- Department of Endocrinology and Metabolism, The Third Affiliated Hospital of Sun Yat-Sen University, Guangdong Provincial Key Laboratory of Diabetology, Guangzhou 510630, China
| | - Hongyun Lu
- Department of Endocrinology and Metabolism, The Fifth Affiliated Hospital of Sun Yat-Sen University, Zhuhai 519000, China
| | - Hangya Peng
- Department of Endocrinology and Metabolism, The Third Affiliated Hospital of Sun Yat-Sen University, Guangdong Provincial Key Laboratory of Diabetology, Guangzhou 510630, China
| | - Chuwen Lin
- Department of Endocrinology and Metabolism, The Third Affiliated Hospital of Sun Yat-Sen University, Guangdong Provincial Key Laboratory of Diabetology, Guangzhou 510630, China
| | - Rili Gao
- Department of Endocrinology and Metabolism, The Third Affiliated Hospital of Sun Yat-Sen University, Guangdong Provincial Key Laboratory of Diabetology, Guangzhou 510630, China
| | - Shuo Lin
- Department of Endocrinology and Metabolism, The Third Affiliated Hospital of Sun Yat-Sen University, Guangdong Provincial Key Laboratory of Diabetology, Guangzhou 510630, China
| | - Keyi Lin
- Department of Endocrinology and Metabolism, The Third Affiliated Hospital of Sun Yat-Sen University, Guangdong Provincial Key Laboratory of Diabetology, Guangzhou 510630, China
| | - Kunying Liu
- Department of Endocrinology and Metabolism, The Third Affiliated Hospital of Sun Yat-Sen University, Guangdong Provincial Key Laboratory of Diabetology, Guangzhou 510630, China
| | - Yan Jiang
- Department of Endocrinology and Metabolism, The Third Affiliated Hospital of Sun Yat-Sen University, Guangdong Provincial Key Laboratory of Diabetology, Guangzhou 510630, China
| | - Jianping Weng
- Department of Endocrinology and Metabolism, The Third Affiliated Hospital of Sun Yat-Sen University, Guangdong Provincial Key Laboratory of Diabetology, Guangzhou 510630, China
| | - Longyi Zeng
- Department of Endocrinology and Metabolism, The Third Affiliated Hospital of Sun Yat-Sen University, Guangdong Provincial Key Laboratory of Diabetology, Guangzhou 510630, China.
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192
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Hong SW, Lee J, Cho JH, Kwon H, Park SE, Rhee EJ, Park CY, Oh KW, Park SW, Lee WY. Pioglitazone Attenuates Palmitate-Induced Inflammation and Endoplasmic Reticulum Stress in Pancreatic β-Cells. Endocrinol Metab (Seoul) 2018; 33:105-113. [PMID: 29589392 PMCID: PMC5874186 DOI: 10.3803/enm.2018.33.1.105] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/05/2017] [Revised: 01/08/2018] [Accepted: 01/09/2018] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND The nuclear receptor peroxisome proliferator-activator gamma (PPARγ) is a useful therapeutic target for obesity and diabetes, but its role in protecting β-cell function and viability is unclear. METHODS To identify the potential functions of PPARγ in β-cells, we treated mouse insulinoma 6 (MIN6) cells with the PPARγ agonist pioglitazone in conditions of lipotoxicity, endoplasmic reticulum (ER) stress, and inflammation. RESULTS Palmitate-treated cells incubated with pioglitazone exhibited significant improvements in glucose-stimulated insulin secretion and the repression of apoptosis, as shown by decreased caspase-3 cleavage and poly (adenosine diphosphate [ADP]-ribose) polymerase activity. Pioglitazone also reversed the palmitate-induced expression of inflammatory cytokines (tumor necrosis factor α, interleukin 6 [IL-6], and IL-1β) and ER stress markers (phosphor-eukaryotic translation initiation factor 2α, glucose-regulated protein 78 [GRP78], cleaved-activating transcription factor 6 [ATF6], and C/EBP homologous protein [CHOP]), and pioglitazone significantly attenuated inflammation and ER stress in lipopolysaccharide- or tunicamycin-treated MIN6 cells. The protective effect of pioglitazone was also tested in pancreatic islets from high-fat-fed KK-Ay mice administered 0.02% (wt/wt) pioglitazone or vehicle for 6 weeks. Pioglitazone remarkably reduced the expression of ATF6α, GRP78, and monocyte chemoattractant protein-1, prevented α-cell infiltration into the pancreatic islets, and upregulated glucose transporter 2 (Glut2) expression in β-cells. Moreover, the preservation of β-cells by pioglitazone was accompanied by a significant reduction of blood glucose levels. CONCLUSION Altogether, these results support the proposal that PPARγ agonists not only suppress insulin resistance, but also prevent β-cell impairment via protection against ER stress and inflammation. The activation of PPARγ might be a new therapeutic approach for improving β-cell survival and insulin secretion in patients with diabetes mellitus.
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Affiliation(s)
- Seok Woo Hong
- Institute of Medical Research, Kangbuk Samsung Hospital, Sungkyunkwan University School of Medicine, Seoul, Korea
| | - Jinmi Lee
- Institute of Medical Research, Kangbuk Samsung Hospital, Sungkyunkwan University School of Medicine, Seoul, Korea
| | - Jung Hwan Cho
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Kangbuk Samsung Hospital, Sungkyunkwan University School of Medicine, Seoul, Korea
| | - Hyemi Kwon
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Kangbuk Samsung Hospital, Sungkyunkwan University School of Medicine, Seoul, Korea
| | - Se Eun Park
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Kangbuk Samsung Hospital, Sungkyunkwan University School of Medicine, Seoul, Korea
| | - Eun Jung Rhee
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Kangbuk Samsung Hospital, Sungkyunkwan University School of Medicine, Seoul, Korea
| | - Cheol Young Park
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Kangbuk Samsung Hospital, Sungkyunkwan University School of Medicine, Seoul, Korea
| | - Ki Won Oh
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Kangbuk Samsung Hospital, Sungkyunkwan University School of Medicine, Seoul, Korea
| | - Sung Woo Park
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Kangbuk Samsung Hospital, Sungkyunkwan University School of Medicine, Seoul, Korea
| | - Won Young Lee
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Kangbuk Samsung Hospital, Sungkyunkwan University School of Medicine, Seoul, Korea.
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193
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Takai T, Matsuda T, Matsuura Y, Inoue K, Suzuki E, Kanno A, Kimura-Koyanagi M, Asahara SI, Hatano N, Ogawa W, Kido Y. Casein kinase 2 phosphorylates and stabilizes C/EBPβ in pancreatic β cells. Biochem Biophys Res Commun 2018; 497:451-456. [PMID: 29448105 DOI: 10.1016/j.bbrc.2018.02.108] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2018] [Accepted: 02/11/2018] [Indexed: 12/27/2022]
Abstract
During the development of type 2 diabetes, endoplasmic reticulum (ER) stress leads to pancreatic β cell failure. CCAAT/enhancer-binding protein (C/EBP) β is highly induced by ER stress and AMP-activated protein kinase (AMPK) suppression in pancreatic β cells, and its accumulation reduces pancreatic β cell mass. We investigated the phosphorylation state of C/EBPβ under these conditions. Casein kinase 2 (CK2) was found to co-localize with C/EBPβ in MIN6 cells. It phosphorylated S222 of C/EBPβ, a previously unidentified phosphorylation site. We found that C/EBPβ is phosphorylated by CK2 under AMPK suppression and ER stress, which are important from the viewpoint of the worsening pathological condition of type 2 diabetes, such as decreased insulin secretion and apoptosis of pancreatic β cells.
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Affiliation(s)
- Tomoko Takai
- Division of Diabetes and Endocrinology, Department of Internal Medicine, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Tomokazu Matsuda
- Division of Diabetes and Endocrinology, Department of Internal Medicine, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Yuki Matsuura
- Division of Metabolism and Disease, Department of Biophysics, Kobe University Graduate School of Health Sciences, Kobe, Japan
| | - Kaho Inoue
- Division of Metabolism and Disease, Department of Biophysics, Kobe University Graduate School of Health Sciences, Kobe, Japan
| | - Emi Suzuki
- Division of Diabetes and Endocrinology, Department of Internal Medicine, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Ayumi Kanno
- Division of Diabetes and Endocrinology, Department of Internal Medicine, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Maki Kimura-Koyanagi
- Division of Diabetes and Endocrinology, Department of Internal Medicine, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Shun-Ichiro Asahara
- Division of Diabetes and Endocrinology, Department of Internal Medicine, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Naoya Hatano
- The Integrated Center for Mass Spectrometry, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Wataru Ogawa
- Division of Diabetes and Endocrinology, Department of Internal Medicine, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Yoshiaki Kido
- Division of Diabetes and Endocrinology, Department of Internal Medicine, Kobe University Graduate School of Medicine, Kobe, Japan; Division of Metabolism and Disease, Department of Biophysics, Kobe University Graduate School of Health Sciences, Kobe, Japan.
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194
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Ho N, Xu C, Thibault G. From the unfolded protein response to metabolic diseases - lipids under the spotlight. J Cell Sci 2018; 131:131/3/jcs199307. [PMID: 29439157 DOI: 10.1242/jcs.199307] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
The unfolded protein response (UPR) is classically viewed as a stress response pathway to maintain protein homeostasis at the endoplasmic reticulum (ER). However, it has recently emerged that the UPR can be directly activated by lipid perturbation, independently of misfolded proteins. Comprising primarily phospholipids, sphingolipids and sterols, individual membranes can contain hundreds of distinct lipids. Even with such complexity, lipid distribution in a cell is tightly regulated by mechanisms that remain incompletely understood. It is therefore unsurprising that lipid dysregulation can be a key factor in disease development. Recent advances in analysis of lipids and their regulators have revealed remarkable mechanisms and connections to other cellular pathways including the UPR. In this Review, we summarize the current understanding in UPR transducers functioning as lipid sensors and the interplay between lipid metabolism and ER homeostasis in the context of metabolic diseases. We attempt to provide a framework consisting of a few key principles to integrate the different lines of evidence and explain this rather complicated mechanism.
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Affiliation(s)
- Nurulain Ho
- School of Biological Sciences, Nanyang Technological University, Singapore, 637551
| | - Chengchao Xu
- Whitehead Institute for Biomedical Research, 455 Main Street, Cambridge, MA 02142-1479, USA
| | - Guillaume Thibault
- School of Biological Sciences, Nanyang Technological University, Singapore, 637551
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195
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Szpigel A, Hainault I, Carlier A, Venteclef N, Batto AF, Hajduch E, Bernard C, Ktorza A, Gautier JF, Ferré P, Bourron O, Foufelle F. Lipid environment induces ER stress, TXNIP expression and inflammation in immune cells of individuals with type 2 diabetes. Diabetologia 2018; 61:399-412. [PMID: 28988346 DOI: 10.1007/s00125-017-4462-5] [Citation(s) in RCA: 96] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/20/2017] [Accepted: 08/24/2017] [Indexed: 02/04/2023]
Abstract
AIMS/HYPOTHESIS Obesity and type 2 diabetes are concomitant with low-grade inflammation affecting insulin sensitivity and insulin secretion. Recently, the thioredoxin interacting protein (TXNIP) has been implicated in the activation process of the NOD-like receptor family, pyrin domain containing 3 (NLRP3) inflammasome. In this study, we aim to determine whether the expression of TXNIP is altered in the circulating immune cells of individuals with type 2 vs type 1 diabetes and whether this can be related to specific causes and consequences of inflammation. METHODS The expression of TXNIP, inflammatory markers, markers of the unfolded protein response (UPR) to endoplasmic reticulum (ER) stress and enzymes involved in sphingolipid metabolism was quantified by quantitative reverse transcription real-time PCR (qRT-PCR) in peripheral blood mononuclear cells (PBMCs) of 13 non-diabetic individuals, 23 individuals with type 1 diabetes and 81 with type 2 diabetes. A lipidomic analysis on the plasma of 13 non-diabetic individuals, 35 individuals with type 1 diabetes and 94 with type 2 diabetes was performed. The effects of ER stress or of specific lipids on TXNIP and inflammatory marker expression were analysed in human monocyte-derived macrophages (HMDMs) and THP-1 cells. RESULTS The expression of TXNIP and inflammatory and UPR markers was increased in the PBMCs of individuals with type 2 diabetes when compared with non-diabetic individuals or individuals with type 1 diabetes. TXNIP expression was significantly correlated with plasma fasting glucose, plasma triacylglycerol concentrations and specific UPR markers. Induction of ER stress in THP-1 cells or cultured HMDMs led to increased expression of UPR markers, TXNIP, NLRP3 and IL-1β. Conversely, a chemical chaperone reduced the expression of UPR markers and TXNIP in PBMCs of individuals with type 2 diabetes. The lipidomic plasma analysis revealed an increased concentration of saturated dihydroceramide and sphingomyelin in individuals with type 2 diabetes when compared with non-diabetic individuals and individuals with type 1 diabetes. In addition, the expression of specific enzymes of sphingolipid metabolism, dihydroceramide desaturase 1 and sphingomyelin synthase 1, was increased in the PBMCs of individuals with type 2 diabetes. Palmitate or C2 ceramide induced ER stress in macrophages as well as increased expression of TXNIP, NLRP3 and IL-1β. CONCLUSIONS/INTERPRETATION In individuals with type 2 diabetes, circulating immune cells display an inflammatory phenotype that can be linked to ER stress and TXNIP expression. Immune cell ER stress can in turn be linked to the specific exogenous and endogenous lipid environment found in type 2 diabetes.
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Affiliation(s)
- Anaïs Szpigel
- Inserm, UMRS 1138, Sorbonne Universités, UPMC Univ Paris 06; Sorbonne Paris Cité, Université Paris Descartes, Université Paris Diderot; Centre de Recherche des Cordeliers, 15 rue de l'école de médicine, 75006, Paris, France
- Institut de Recherches Servier, Suresnes, France
| | - Isabelle Hainault
- Inserm, UMRS 1138, Sorbonne Universités, UPMC Univ Paris 06; Sorbonne Paris Cité, Université Paris Descartes, Université Paris Diderot; Centre de Recherche des Cordeliers, 15 rue de l'école de médicine, 75006, Paris, France
| | - Aurélie Carlier
- Department of Endocrinology, Nutrition, and Diabetes, Pitié-Salpêtrière Hospital, Assistance Publique-Hôpitaux de Paris, Paris, France
| | - Nicolas Venteclef
- Inserm, UMRS 1138, Sorbonne Universités, UPMC Univ Paris 06; Sorbonne Paris Cité, Université Paris Descartes, Université Paris Diderot; Centre de Recherche des Cordeliers, 15 rue de l'école de médicine, 75006, Paris, France
| | - Anne-Françoise Batto
- Inserm, UMRS 1138, Sorbonne Universités, UPMC Univ Paris 06; Sorbonne Paris Cité, Université Paris Descartes, Université Paris Diderot; Centre de Recherche des Cordeliers, 15 rue de l'école de médicine, 75006, Paris, France
| | - Eric Hajduch
- Inserm, UMRS 1138, Sorbonne Universités, UPMC Univ Paris 06; Sorbonne Paris Cité, Université Paris Descartes, Université Paris Diderot; Centre de Recherche des Cordeliers, 15 rue de l'école de médicine, 75006, Paris, France
| | | | - Alain Ktorza
- Institut de Recherches Servier, Suresnes, France
| | - Jean-François Gautier
- Inserm, UMRS 1138, Sorbonne Universités, UPMC Univ Paris 06; Sorbonne Paris Cité, Université Paris Descartes, Université Paris Diderot; Centre de Recherche des Cordeliers, 15 rue de l'école de médicine, 75006, Paris, France
- Department of Diabetes and Endocrinology, Lariboisière Hospital, DHU FIRE, Assistance Publique-Hôpitaux de Paris, Paris, France
| | - Pascal Ferré
- Inserm, UMRS 1138, Sorbonne Universités, UPMC Univ Paris 06; Sorbonne Paris Cité, Université Paris Descartes, Université Paris Diderot; Centre de Recherche des Cordeliers, 15 rue de l'école de médicine, 75006, Paris, France
- Department of Oncology and Endocrine Biochemistry, Pitié-Salpêtrière Hospital, Assistance Publique-Hôpitaux de Paris, Paris, France
| | - Olivier Bourron
- Inserm, UMRS 1138, Sorbonne Universités, UPMC Univ Paris 06; Sorbonne Paris Cité, Université Paris Descartes, Université Paris Diderot; Centre de Recherche des Cordeliers, 15 rue de l'école de médicine, 75006, Paris, France
- Department of Endocrinology, Nutrition, and Diabetes, Pitié-Salpêtrière Hospital, Assistance Publique-Hôpitaux de Paris, Paris, France
| | - Fabienne Foufelle
- Inserm, UMRS 1138, Sorbonne Universités, UPMC Univ Paris 06; Sorbonne Paris Cité, Université Paris Descartes, Université Paris Diderot; Centre de Recherche des Cordeliers, 15 rue de l'école de médicine, 75006, Paris, France.
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196
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Arunagiri A, Haataja L, Cunningham CN, Shrestha N, Tsai B, Qi L, Liu M, Arvan P. Misfolded proinsulin in the endoplasmic reticulum during development of beta cell failure in diabetes. Ann N Y Acad Sci 2018; 1418:5-19. [PMID: 29377149 DOI: 10.1111/nyas.13531] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2017] [Revised: 09/14/2017] [Accepted: 09/25/2017] [Indexed: 02/06/2023]
Abstract
The endoplasmic reticulum (ER) is broadly distributed throughout the cytoplasm of pancreatic beta cells, and this is where all proinsulin is initially made. Healthy beta cells can synthesize 6000 proinsulin molecules per second. Ordinarily, nascent proinsulin entering the ER rapidly folds via the formation of three evolutionarily conserved disulfide bonds (B7-A7, B19-A20, and A6-A11). A modest amount of proinsulin misfolding, including both intramolecular disulfide mispairing and intermolecular disulfide-linked protein complexes, is a natural by-product of proinsulin biosynthesis, as is the case for many proteins. The steady-state level of misfolded proinsulin-a potential ER stressor-is linked to (1) production rate, (2) ER environment, (3) presence or absence of naturally occurring (mutational) defects in proinsulin, and (4) clearance of misfolded proinsulin molecules. Accumulation of misfolded proinsulin beyond a certain threshold begins to interfere with the normal intracellular transport of bystander proinsulin, leading to diminished insulin production and hyperglycemia, as well as exacerbating ER stress. This is most obvious in mutant INS gene-induced Diabetes of Youth (MIDY; an autosomal dominant disease) but also likely to occur in type 2 diabetes owing to dysregulation in proinsulin synthesis, ER folding environment, or clearance.
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Affiliation(s)
- Anoop Arunagiri
- Division of Metabolism, Endocrinology & Diabetes, University of Michigan, Ann Arbor, Michigan
| | - Leena Haataja
- Division of Metabolism, Endocrinology & Diabetes, University of Michigan, Ann Arbor, Michigan
| | - Corey N Cunningham
- Cellular and Molecular Biology Program, University of Michigan, Ann Arbor, Michigan
| | - Neha Shrestha
- Department of Molecular & Integrative Physiology, University of Michigan, Ann Arbor, Michigan
| | - Billy Tsai
- Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, Michigan
| | - Ling Qi
- Department of Molecular & Integrative Physiology, University of Michigan, Ann Arbor, Michigan
| | - Ming Liu
- Division of Metabolism, Endocrinology & Diabetes, University of Michigan, Ann Arbor, Michigan.,Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin, China
| | - Peter Arvan
- Division of Metabolism, Endocrinology & Diabetes, University of Michigan, Ann Arbor, Michigan
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197
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Oh YS, Bae GD, Baek DJ, Park EY, Jun HS. Fatty Acid-Induced Lipotoxicity in Pancreatic Beta-Cells During Development of Type 2 Diabetes. Front Endocrinol (Lausanne) 2018; 9:384. [PMID: 30061862 PMCID: PMC6054968 DOI: 10.3389/fendo.2018.00384] [Citation(s) in RCA: 182] [Impact Index Per Article: 30.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/07/2018] [Accepted: 06/25/2018] [Indexed: 12/20/2022] Open
Abstract
Type 2 diabetes is caused by chronic insulin resistance and progressive decline in beta-cell function. Optimal beta-cell function and mass is essential for glucose homeostasis and beta-cell impairment leads to the development of diabetes. Elevated levels of circulating fatty acids (FAs) and disturbances in lipid metabolism regulation are associated with obesity, and they are major factors influencing the increase in the incidence of type 2 diabetes. Chronic free FA (FFA) treatment induces insulin resistance and beta-cell dysfunction; therefore, reduction of elevated plasma FFA levels might be an important therapeutic target in obesity and type 2 diabetes. Lipid signals via receptors, and intracellular mechanisms are involved in FFA-induced apoptosis. In this paper, we discuss lipid actions in beta cells, including effects on metabolic pathways and stress responses, to help further understand the molecular mechanisms of lipotoxicity-induced type 2 diabetes.
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Affiliation(s)
- Yoon S. Oh
- Department of Food and Nutrition, Eulji University, Seongnam, South Korea
- *Correspondence: Yoon S. Oh
| | - Gong D. Bae
- Department of Molecular Medicine, Lee Gil Ya Cancer and Diabetes Institute, Gachon University, Incheon, South Korea
| | - Dong J. Baek
- College of Pharmacy and Natural Medicine Research Institute, Mokpo National University, Jeonnam, South Korea
| | - Eun-Young Park
- College of Pharmacy and Natural Medicine Research Institute, Mokpo National University, Jeonnam, South Korea
| | - Hee-Sook Jun
- Department of Molecular Medicine, Lee Gil Ya Cancer and Diabetes Institute, Gachon University, Incheon, South Korea
- Gachon Institute of Pharmaceutical Science, College of Pharmacy, Gachon University, Incheon, South Korea
- Gachon University Gil Medical Center, Gachon Medical and Convergence Institute, Incheon, South Korea
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198
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Kefalas G, Larose L. PERK leads a hub dictating pancreatic β cell homoeostasis. Biol Cell 2017; 110:27-32. [DOI: 10.1111/boc.201700059] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2017] [Accepted: 11/05/2017] [Indexed: 12/30/2022]
Affiliation(s)
- George Kefalas
- Division of Experimental Medicine; Department of Medicine; McGill University and the Research Institute of McGill University Health Centre; Montreal Quebec Canada
| | - Louise Larose
- Division of Experimental Medicine; Department of Medicine; McGill University and the Research Institute of McGill University Health Centre; Montreal Quebec Canada
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199
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Duan K, Ghosh G, Lo JF. Optimizing Multiplexed Detections of Diabetes Antibodies via Quantitative Microfluidic Droplet Array. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2017; 13:10.1002/smll.201702323. [PMID: 28990274 PMCID: PMC5755373 DOI: 10.1002/smll.201702323] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/08/2017] [Revised: 08/11/2017] [Indexed: 05/02/2023]
Abstract
Sensitive, single volume detections of multiple diabetes antibodies can provide immunoprofiling and early screening of at-risk patients. To advance the state-of-the-art suspension assays for diabetes antibodies, porous hydrogel droplets are leveraged in microfluidic serpentine arrays to enhance reagent transport. This spatially multiplexed assay is applied to the detection of antibodies against insulin, glutamic acid decarboxylase, and insulinoma-associated protein 2. Optimization of assay protocol results in a shortened assay time of 2 h, with better than 20 pg mL Supporting Information detection limits across all three antibodies. Specificity and cross-reactivity tests show negligible background, nonspecific antibody-antigen, and nonspecific antibody-antibody bindings. Multiplexed detections are able to measure within 15% of target concentrations from low to high ranges. The technique enables quantifications of as little as 8000 molecules in each 500 µm droplet in a single volume, multiplexed assay format, a breakthrough necessary for the adoption of diabetes panels for clinical screening and monitoring in the future.
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Affiliation(s)
- Kai Duan
- Bioengineering Program, Department of Mechanical Engineering, University of Michigan at Dearborn, Dearborn, MI, 48128, USA
| | - Gargi Ghosh
- Bioengineering Program, Department of Mechanical Engineering, University of Michigan at Dearborn, Dearborn, MI, 48128, USA
| | - Joe Fujiou Lo
- Bioengineering Program, Department of Mechanical Engineering, University of Michigan at Dearborn, Dearborn, MI, 48128, USA
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200
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Mehmeti I, Lortz S, Avezov E, Jörns A, Lenzen S. ER-resident antioxidative GPx7 and GPx8 enzyme isoforms protect insulin-secreting INS-1E β-cells against lipotoxicity by improving the ER antioxidative capacity. Free Radic Biol Med 2017; 112:121-130. [PMID: 28751022 DOI: 10.1016/j.freeradbiomed.2017.07.021] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/07/2017] [Revised: 07/20/2017] [Accepted: 07/22/2017] [Indexed: 12/16/2022]
Abstract
Increased circulating levels of saturated fatty acids (FFAs) and glucose are considered to be major mediators of β-cell dysfunction and death in T2DM. Although it has been proposed that endoplasmic reticulum (ER) and oxidative stress play a crucial role in gluco/lipotoxicity, their interplay and relative contribution to β-cell dysfunction and apoptosis has not been fully elucidated. In addition it is still unclear how palmitate - the physiologically most abundant long-chain saturated FFA - elicits ER stress and which immediate signals commit β-cells to apoptosis. To study the underlying mechanisms of palmitate-mediated ER stress and β-cell toxicity, we exploited the observation that the recently described ER-resident GPx7 and GPx8 are not expressed in rat β-cells. Expression of GPx7 or GPx8 attenuated FFAs-mediated H2O2 generation, ER stress, and apoptosis induction. These results could be confirmed by a H2O2-specific inactivating ER catalase, indicating that accumulation of H2O2 in the ER lumen is critical in FFA-induced ER stress. Furthermore, neither the expression of GPx7 nor of GPx8 increased insulin content or facilitated disulfide bond formation in insulin-secreting INS-1E cells. Hence, reduction of H2O2 by ER-GPx isoforms is not rate-limiting in oxidative protein folding in rat β-cells. These data suggest that FFA-mediated ER stress is partially dependent on oxidative stress and selective expression of GPx7 or GPx8 improves the ER antioxidative capacity of rat β-cells without compromising insulin production and the oxidative protein folding machinery.
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Affiliation(s)
- Ilir Mehmeti
- Institute of Clinical Biochemistry, Hannover Medical School, Hannover, Germany.
| | - Stephan Lortz
- Institute of Clinical Biochemistry, Hannover Medical School, Hannover, Germany
| | - Edward Avezov
- University of Cambridge, Cambridge Institute for Medical Research, the Wellcome Trust MRC Institute of Metabolic Science and NIHR Cambridge Biomedical Research Centre, Cambridge CB2 0XY, United Kingdom
| | - Anne Jörns
- Institute of Clinical Biochemistry, Hannover Medical School, Hannover, Germany
| | - Sigurd Lenzen
- Institute of Clinical Biochemistry, Hannover Medical School, Hannover, Germany; Institute of Experimental Diabetes Research, Hannover Medical School, Hannover, Germany.
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