1
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He Z, Liu Q, Wang Y, Zhao B, Zhang L, Yang X, Wang Z. The role of endoplasmic reticulum stress in type 2 diabetes mellitus mechanisms and impact on islet function. PeerJ 2025; 13:e19192. [PMID: 40166045 PMCID: PMC11956770 DOI: 10.7717/peerj.19192] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2024] [Accepted: 02/26/2025] [Indexed: 04/02/2025] Open
Abstract
Type 2 diabetes mellitus (T2DM) is a globally prevalent metabolic disorder characterized by insulin resistance and dysfunction of islet cells. Endoplasmic reticulum (ER) stress plays a crucial role in the pathogenesis and progression of T2DM, especially in the function and survival of β-cells. β-cells are particularly sensitive to ER stress because they require substantial insulin synthesis and secretion energy. In the early stages of T2DM, the increased demand for insulin exacerbates β-cell ER stress. Although the unfolded protein response (UPR) can temporarily alleviate this stress, prolonged or excessive stress leads to pancreatic cell dysfunction and apoptosis, resulting in insufficient insulin secretion. This review explores the mechanisms of ER stress in T2DM, particularly its impact on islet cells. We discuss how ER stress activates UPR signaling pathways to regulate protein folding and degradation, but when stress becomes excessive, these pathways may contribute to β-cell death. A deeper understanding of how ER stress impacts islet cells could lead to the development of novel T2DM treatment strategies aimed at improving islet function and slowing disease progression.
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Affiliation(s)
- Zhaxicao He
- Gansu University of Chinese Medicine, Lanzhou, China
| | - Qian Liu
- Gansu University of Chinese Medicine, Lanzhou, China
| | - Yan Wang
- Gansu University of Chinese Medicine, Lanzhou, China
| | - Bing Zhao
- Gansu University of Chinese Medicine, Lanzhou, China
| | - Lumei Zhang
- Gansu University of Chinese Medicine, Lanzhou, China
| | - Xia Yang
- Tianshui Hospital of Traditional Chinese Medicine, Tianshui, China
| | - Zhigang Wang
- Gansu University of Chinese Medicine, Lanzhou, China
- Tianshui Hospital of Traditional Chinese Medicine, Tianshui, China
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2
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Lee C, Kono T, Syed F, Weaver SA, Sohn P, Wu W, Chang G, Liu J, Slak Rupnik M, Evans‐Molina C. Sodium butyrate prevents cytokine-induced β-cell dysfunction through restoration of stromal interaction molecule 1 expression and activation of store-operated calcium entry. FASEB J 2024; 38:e23853. [PMID: 39120544 PMCID: PMC11607631 DOI: 10.1096/fj.202302501rr] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2023] [Revised: 07/15/2024] [Accepted: 07/21/2024] [Indexed: 08/10/2024]
Abstract
Sodium butyrate (NaB) improves β-cell function in preclinical models of diabetes; however, the mechanisms underlying these beneficial effects have not been fully elucidated. In this study, we investigated the impact of NaB on β-cell function and calcium (Ca2+) signaling using ex vivo and in vitro models of diabetes. Our results show that NaB significantly improved glucose-stimulated insulin secretion in islets from human organ donors with type 2 diabetes and in cytokine-treated INS-1 β cells. Consistently, NaB improved glucose-stimulated Ca2+ oscillations in mouse islets treated with proinflammatory cytokines. Because the oscillatory phenotype of Ca2+ in the β cell is governed by changes in endoplasmic reticulum (ER) Ca2+ levels, we explored the relationship between NaB and store-operated calcium entry (SOCE), a rescue mechanism that acts to refill ER Ca2+ levels through STIM1-mediated gating of plasmalemmal Orai channels. We found that NaB treatment preserved basal ER Ca2+ levels and restored SOCE in IL-1β-treated INS-1 cells. Furthermore, we linked these changes with the restoration of STIM1 levels in cytokine-treated INS-1 cells and mouse islets, and we found that NaB treatment was sufficient to prevent β-cell death in response to IL-1β treatment. Mechanistic experiments revealed that NaB mediated these beneficial effects in the β-cell through histone deacetylase (HDAC) inhibition, iNOS suppression, and modulation of AKT-GSK-3 signaling. Taken together, these data support a model whereby NaB treatment promotes β-cell function and Ca2+ homeostasis under proinflammatory conditions through pleiotropic effects that are linked with maintenance of SOCE. These results also suggest a relationship between β-cell SOCE and gut microbiome-derived butyrate that may be relevant in the treatment and prevention of diabetes.
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Affiliation(s)
- Chih‐Chun Lee
- Center for Diabetes and Metabolic DiseasesIndiana University School of MedicineIndianapolisIndianaUSA
- Herman B Wells Center for Pediatric ResearchIndiana University School of MedicineIndianapolisIndianaUSA
| | - Tatsuyoshi Kono
- Center for Diabetes and Metabolic DiseasesIndiana University School of MedicineIndianapolisIndianaUSA
- Herman B Wells Center for Pediatric ResearchIndiana University School of MedicineIndianapolisIndianaUSA
| | - Farooq Syed
- Center for Diabetes and Metabolic DiseasesIndiana University School of MedicineIndianapolisIndianaUSA
- Herman B Wells Center for Pediatric ResearchIndiana University School of MedicineIndianapolisIndianaUSA
| | - Staci A. Weaver
- Center for Diabetes and Metabolic DiseasesIndiana University School of MedicineIndianapolisIndianaUSA
- Herman B Wells Center for Pediatric ResearchIndiana University School of MedicineIndianapolisIndianaUSA
- Department of Biochemistry and Molecular BiologyIndiana University School of MedicineIndianapolisIndianaUSA
| | - Paul Sohn
- Center for Diabetes and Metabolic DiseasesIndiana University School of MedicineIndianapolisIndianaUSA
- Herman B Wells Center for Pediatric ResearchIndiana University School of MedicineIndianapolisIndianaUSA
| | - Wenting Wu
- Center for Diabetes and Metabolic DiseasesIndiana University School of MedicineIndianapolisIndianaUSA
- Herman B Wells Center for Pediatric ResearchIndiana University School of MedicineIndianapolisIndianaUSA
- Department of Medical & Molecular GeneticsIndiana University School of MedicineIndianapolisIndianaUSA
| | - Garrick Chang
- Department of PhysicsIndiana University IndianapolisIndianpolisIndianaUSA
| | - Jing Liu
- Department of Physics and AstronomyPurdue UniversityWest LafayetteIndianaUSA
| | - Marjan Slak Rupnik
- Center for Physiology and PharmacologyMedical University of ViennaWienAustria
- Alma Mater Europaea – European Center MariborMariborSlovenia
| | - Carmella Evans‐Molina
- Center for Diabetes and Metabolic DiseasesIndiana University School of MedicineIndianapolisIndianaUSA
- Herman B Wells Center for Pediatric ResearchIndiana University School of MedicineIndianapolisIndianaUSA
- Department of Biochemistry and Molecular BiologyIndiana University School of MedicineIndianapolisIndianaUSA
- Department of PediatricsIndiana University School of MedicineIndianapolisIndianaUSA
- Department of MedicineIndiana University School of MedicineIndianapolisIndianaUSA
- Department of Anatomy, Cell Biology, and PhysiologyIndiana University School of MedicineIndianapolisIndianaUSA
- Richard L. Roudebush VA Medical CenterIndianapolisIndianaUSA
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3
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Saloman JL, Epouhe AY, Ruff CF, Albers KM. PDX1, a transcription factor essential for organ differentiation, regulates SERCA-dependent Ca 2+ homeostasis in sensory neurons. Cell Calcium 2024; 120:102884. [PMID: 38574509 PMCID: PMC11188734 DOI: 10.1016/j.ceca.2024.102884] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2024] [Revised: 03/13/2024] [Accepted: 03/31/2024] [Indexed: 04/06/2024]
Abstract
Pancreatic and duodenal homeobox 1 (PDX1) is a transcription factor required for the development and differentiation of the pancreas. Previous studies indicated that PDX1 expression was restricted to the gastrointestinal tract. Using a cre-dependent reporter, we observed PDX1-dependent expression of tdtomato (PDX1-tom) in a subpopulation of sensory nerves. Many of these PDX1-tom afferents expressed the neurofilament 200 protein and projected to the skin. Tdtomato-labeled terminals were associated with hair follicles in the form of longitudinal and circumferential lanceolate endings suggesting a role in tactile and proprioceptive perception. To begin to examine the functional significance of PDX1 in afferents, we used Fura-2 imaging to examine calcium (Ca2+) handling under naïve and nerve injury conditions. Neuropathic injury is associated with increased intracellular Ca2+ signaling that in part results from dysregulation of the sarco/endoplasmic reticulum calcium transport ATPase (SERCA). Here we demonstrate that under naïve conditions, PDX1 regulates expression of the SERCA2B isoform in sensory neurons. In response to infraorbital nerve injury, a significant reduction of PDX1 and SERCA2B expression and dysregulation of Ca2+ handling occurs in PDX1-tom trigeminal ganglia neurons. The identification of PDX1 expression in the somatosensory system and its regulation of SERCA2B and Ca2+ handling provide a new mechanism to explain pathological changes in primary afferents that may contribute to pain associated with nerve injury.
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Affiliation(s)
- Jami L Saloman
- Department of Medicine, Division of Gastroenterology, Hepatology and Nutrition, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA; Department of Neurobiology, Center for Neuroscience and Center for Pain Research, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA.
| | - Ariel Y Epouhe
- Department of Neurobiology, Center for Neuroscience and Center for Pain Research, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Catherine F Ruff
- Department of Neurobiology, Center for Neuroscience and Center for Pain Research, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Kathryn M Albers
- Department of Neurobiology, Center for Neuroscience and Center for Pain Research, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
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4
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Mbara KC, Fotsing MC, Ndinteh DT, Mbeb CN, Nwagwu CS, Khan R, Mokhetho KC, Baijnath H, Nlooto M, Mokhele S, Leonard CM, Tembu VJ, Tarirai C. Endoplasmic reticulum stress in pancreatic β-cell dysfunction: The potential therapeutic role of dietary flavonoids. CURRENT RESEARCH IN PHARMACOLOGY AND DRUG DISCOVERY 2024; 6:100184. [PMID: 38846008 PMCID: PMC11153890 DOI: 10.1016/j.crphar.2024.100184] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2024] [Revised: 05/21/2024] [Accepted: 05/22/2024] [Indexed: 06/09/2024] Open
Abstract
Diabetes mellitus (DM) is a global health burden that is characterized by the loss or dysfunction of pancreatic β-cells. In pancreatic β-cells, endoplasmic reticulum (ER) stress is a fact of life that contributes to β-cell loss or dysfunction. Despite recent advances in research, the existing treatment approaches such as lifestyle modification and use of conventional therapeutics could not prevent the loss or dysfunction of pancreatic β-cells to abrogate the disease progression. Therefore, targeting ER stress and the consequent unfolded protein response (UPR) in pancreatic β-cells may be a potential therapeutic strategy for diabetes treatment. Dietary phytochemicals have therapeutic applications in human health owing to their broad spectrum of biochemical and pharmacological activities. Flavonoids, which are commonly obtained from fruits and vegetables worldwide, have shown promising prospects in alleviating ER stress. Dietary flavonoids including quercetin, kaempferol, myricetin, isorhamnetin, fisetin, icariin, apigenin, apigetrin, vitexin, baicalein, baicalin, nobiletin hesperidin, naringenin, epigallocatechin 3-O-gallate hesperidin (EGCG), tectorigenin, liquiritigenin, and acacetin have shown inhibitory effects on ER stress in pancreatic β-cells. Dietary flavonoids modulate ER stress signaling components, chaperone proteins, transcription factors, oxidative stress, autophagy, apoptosis, and inflammatory responses to exert their pharmacological effects on pancreatic β-cells ER stress. This review focuses on the role of dietary flavonoids as potential therapeutic adjuvants in preserving pancreatic β-cells from ER stress. Highlights of the underlying mechanisms of action are also presented as well as possible strategies for clinical translation in the management of DM.
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Affiliation(s)
- Kingsley C. Mbara
- Nanomedicines Manufacturing, Biopharmaceutics and Diagnostics Research Laboratory, Department of Pharmaceutical Sciences, Tshwane University of Technology, Private Bag X680, Pretoria, 0001, South Africa
| | - Marthe C.D. Fotsing
- Drug Discovery and Smart Molecules Research Laboratory, Centre for Natural Products Research (CNPR), Department of Chemical Sciences, University of Johannesburg, Doornfontein, Johannesburg, 2028, South Africa
| | - Derek T. Ndinteh
- Drug Discovery and Smart Molecules Research Laboratory, Centre for Natural Products Research (CNPR), Department of Chemical Sciences, University of Johannesburg, Doornfontein, Johannesburg, 2028, South Africa
| | - Claudine N. Mbeb
- Nanomedicines Manufacturing, Biopharmaceutics and Diagnostics Research Laboratory, Department of Pharmaceutical Sciences, Tshwane University of Technology, Private Bag X680, Pretoria, 0001, South Africa
| | - Chinekwu S. Nwagwu
- Drug Delivery and Nanomedicines Research Laboratory, Department of Pharmaceutics, University of Nigeria, Nsukka, Enugu State, Nigeria
| | - Rene Khan
- Discipline of Medical Biochemistry, School of Laboratory Medicine and Medical Science, University of KwaZulu-Natal, Durban, South Africa
| | - Kopang C. Mokhetho
- Nanomedicines Manufacturing, Biopharmaceutics and Diagnostics Research Laboratory, Department of Pharmaceutical Sciences, Tshwane University of Technology, Private Bag X680, Pretoria, 0001, South Africa
| | - Himansu Baijnath
- Ward Herbarium, School of Life Sciences, University of KwaZulu-Natal, Durban, 4000, KwaZulu-Natal, South Africa
| | - Manimbulu Nlooto
- Department of Pharmaceutical Sciences, Healthcare Sciences, University of Limpopo, South Africa
| | - Shoeshoe Mokhele
- Department of Pharmaceutical Sciences, School of Pharmacy, Sefako Makgatho Health Sciences University, Pretoria, 0208, South Africa
| | - Carmen M. Leonard
- Nanomedicines Manufacturing, Biopharmaceutics and Diagnostics Research Laboratory, Department of Pharmaceutical Sciences, Tshwane University of Technology, Private Bag X680, Pretoria, 0001, South Africa
| | - Vuyelwa J. Tembu
- Natural Products Chemistry Research Laboratory, Department of Chemistry, Tshwane University of Technology, Private Bag X680, Pretoria, 0001, South Africa
| | - Clemence Tarirai
- Nanomedicines Manufacturing, Biopharmaceutics and Diagnostics Research Laboratory, Department of Pharmaceutical Sciences, Tshwane University of Technology, Private Bag X680, Pretoria, 0001, South Africa
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5
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Evans-Molina C. The Ailing β-Cell in Diabetes: Insights From a Trip to the ER: The 2023 Outstanding Scientific Achievement Award Lecture. Diabetes 2024; 73:545-553. [PMID: 38507587 PMCID: PMC10958579 DOI: 10.2337/dbi23-0030] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/13/2023] [Accepted: 12/28/2023] [Indexed: 03/22/2024]
Abstract
The synthesis, processing, and secretion of insulin by the pancreatic β-cell is key for the maintenance of systemic metabolic homeostasis, and loss or dysfunction of β-cells underlies the development of both type 1 diabetes (T1D) and type 2 diabetes (T2D). Work in the Evans-Molina laboratory over the past 15 years has pioneered the idea that regulation of calcium dynamics is critical to β-cell biology and diabetes pathophysiology. In this article, I will share three vignettes from the laboratory that demonstrate our bench-to-bedside approach to determining mechanisms of β-cell stress that could improve therapeutic options and outcomes for individuals living with diabetes. The first of these vignettes will illustrate a role for the sarcoendoplasmic reticulum calcium ATPase (SERCA) pump in the regulation of endoplasmic reticulum (ER) calcium, protein trafficking, and proinsulin processing within the β-cell. The second vignette will highlight how alterations in β-cell calcium signaling intersect with T1D pathogenesis. The final vignette will demonstrate how activation of β-cell stress pathways may serve as an anchor to inform biomarker strategies in T1D. Lastly, I will share my vision for the future of diabetes care, where multiple biomarkers of β-cell stress may be combined with additional immune and metabolic biomarkers to better predict disease risk and improve therapies to prevent or delay T1D development.
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Affiliation(s)
- Carmella Evans-Molina
- Department of Anatomy, Cell Biology, and Physiology, Indiana University School of Medicine, Indianapolis, IN
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, IN
- Department of Medicine, Indiana University School of Medicine, Indianapolis, IN
- Department of Pediatrics, Indiana University School of Medicine, Indianapolis, IN
- Center for Diabetes and Metabolic Diseases, Indiana University School of Medicine, Indianapolis, IN
- Herman B. Wells Center for Pediatric Research, Indiana University School of Medicine, Indianapolis, IN
- Roudebush VA Medical Center, Indianapolis, IN
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Kong L, Zhao Q, Jiang X, Hu J, Jiang Q, Sheng L, Peng X, Wang S, Chen Y, Wan Y, Hou S, Liu X, Ma C, Li Y, Quan L, Chen L, Cui B, Li P. Trimethylamine N-oxide impairs β-cell function and glucose tolerance. Nat Commun 2024; 15:2526. [PMID: 38514666 PMCID: PMC10957989 DOI: 10.1038/s41467-024-46829-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2023] [Accepted: 03/12/2024] [Indexed: 03/23/2024] Open
Abstract
β-Cell dysfunction and β-cell loss are hallmarks of type 2 diabetes (T2D). Here, we found that trimethylamine N-oxide (TMAO) at a similar concentration to that found in diabetes could directly decrease glucose-stimulated insulin secretion (GSIS) in MIN6 cells and primary islets from mice or humans. Elevation of TMAO levels impairs GSIS, β-cell proportion, and glucose tolerance in male C57BL/6 J mice. TMAO inhibits calcium transients through NLRP3 inflammasome-related cytokines and induced Serca2 loss, and a Serca2 agonist reversed the effect of TMAO on β-cell function in vitro and in vivo. Additionally, long-term TMAO exposure promotes β-cell ER stress, dedifferentiation, and apoptosis and inhibits β-cell transcriptional identity. Inhibition of TMAO production improves β-cell GSIS, β-cell proportion, and glucose tolerance in both male db/db and choline diet-fed mice. These observations identify a role for TMAO in β-cell dysfunction and maintenance, and inhibition of TMAO could be an approach for the treatment of T2D.
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Affiliation(s)
- Lijuan Kong
- State Key Laboratory of Bioactive Substance and Function of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
- Diabetes Research Center of Chinese Academy of Medical Sciences, Beijing, China
- CAMS Key Laboratory of Molecular Mechanism and Target Discovery of Metabolic Disorder and Tumorigenesis, Beijing, China
| | - Qijin Zhao
- State Key Laboratory of Bioactive Substance and Function of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
- Diabetes Research Center of Chinese Academy of Medical Sciences, Beijing, China
- CAMS Key Laboratory of Molecular Mechanism and Target Discovery of Metabolic Disorder and Tumorigenesis, Beijing, China
| | - Xiaojing Jiang
- State Key Laboratory of Bioactive Substance and Function of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
- Diabetes Research Center of Chinese Academy of Medical Sciences, Beijing, China
- CAMS Key Laboratory of Molecular Mechanism and Target Discovery of Metabolic Disorder and Tumorigenesis, Beijing, China
| | - Jinping Hu
- State Key Laboratory of Bioactive Substance and Function of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Qian Jiang
- State Key Laboratory of Bioactive Substance and Function of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
- Diabetes Research Center of Chinese Academy of Medical Sciences, Beijing, China
- CAMS Key Laboratory of Molecular Mechanism and Target Discovery of Metabolic Disorder and Tumorigenesis, Beijing, China
| | - Li Sheng
- State Key Laboratory of Bioactive Substance and Function of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Xiaohong Peng
- College of Future Technology, Institute of Molecular Medicine, National Biomedical Imaging Center, Peking University, 100871, Beijing, China
- Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Peking University, 100871, Beijing, China
| | - Shusen Wang
- Tianjin First Central Hospital, Tianjin, China
| | - Yibing Chen
- State Key Laboratory of Bioactive Substance and Function of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
- Diabetes Research Center of Chinese Academy of Medical Sciences, Beijing, China
- CAMS Key Laboratory of Molecular Mechanism and Target Discovery of Metabolic Disorder and Tumorigenesis, Beijing, China
| | - Yanjun Wan
- State Key Laboratory of Bioactive Substance and Function of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
- Diabetes Research Center of Chinese Academy of Medical Sciences, Beijing, China
- CAMS Key Laboratory of Molecular Mechanism and Target Discovery of Metabolic Disorder and Tumorigenesis, Beijing, China
| | - Shaocong Hou
- State Key Laboratory of Bioactive Substance and Function of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
- Diabetes Research Center of Chinese Academy of Medical Sciences, Beijing, China
- CAMS Key Laboratory of Molecular Mechanism and Target Discovery of Metabolic Disorder and Tumorigenesis, Beijing, China
| | - Xingfeng Liu
- State Key Laboratory of Bioactive Substance and Function of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
- Diabetes Research Center of Chinese Academy of Medical Sciences, Beijing, China
- CAMS Key Laboratory of Molecular Mechanism and Target Discovery of Metabolic Disorder and Tumorigenesis, Beijing, China
| | - Chunxiao Ma
- State Key Laboratory of Bioactive Substance and Function of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
- Diabetes Research Center of Chinese Academy of Medical Sciences, Beijing, China
- CAMS Key Laboratory of Molecular Mechanism and Target Discovery of Metabolic Disorder and Tumorigenesis, Beijing, China
| | - Yan Li
- State Key Laboratory of Bioactive Substance and Function of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Li Quan
- Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Peking University, 100871, Beijing, China
| | - Liangyi Chen
- College of Future Technology, Institute of Molecular Medicine, National Biomedical Imaging Center, Peking University, 100871, Beijing, China
- Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Peking University, 100871, Beijing, China
| | - Bing Cui
- State Key Laboratory of Bioactive Substance and Function of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
- CAMS Key Laboratory of Molecular Mechanism and Target Discovery of Metabolic Disorder and Tumorigenesis, Beijing, China
| | - Pingping Li
- State Key Laboratory of Bioactive Substance and Function of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China.
- Diabetes Research Center of Chinese Academy of Medical Sciences, Beijing, China.
- CAMS Key Laboratory of Molecular Mechanism and Target Discovery of Metabolic Disorder and Tumorigenesis, Beijing, China.
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7
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Xiong FR, Lu J, Zhu JJ, Zhao RX, Zhang YC, Yang JK. KCNH6 is essential for insulin secretion by regulating intracellular ER Ca 2+ store. FASEB J 2024; 38:e23490. [PMID: 38363581 DOI: 10.1096/fj.202302194rr] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2023] [Revised: 01/17/2024] [Accepted: 01/30/2024] [Indexed: 02/17/2024]
Abstract
Appropriate Ca2+ concentration in the endoplasmic reticulum (ER), modulating cytosolic Ca2+ signal, serves significant roles in physiological function of pancreatic β cells. To maintaining ER homeostasis, Ca2+ movement across the ER membrane is always accompanied by a simultaneous K+ flux in the opposite direction. KCNH6 was proven to modulate insulin secretion by controlling plasma membrane action potential duration and intracellular Ca2+ influx. Meanwhile, the specific function of KCNH6 in pancreatic β-cells remains unclear. In this study, we found that KCNH6 exhibited mainly ER localization and Kcnh6 β-cell-specific knockout (βKO) mice suffered from abnormal glucose tolerance and impaired insulin secretion in adulthood. ER Ca2+ store was overloaded in islets of βKO mice, which contributed to ER stress and ER stress-induced apoptosis in β cells. Next, we verified that ethanol treatment induced increases in ER Ca2+ store and apoptosis in pancreatic β cells, whereas adenovirus-mediated KCNH6 overexpression in islets attenuated ethanol-induced ER stress and apoptosis. In addition, tail-vein injections of KCNH6 lentivirus rescued KCNH6 expression in βKO mice, restored ER Ca2+ overload and attenuated ER stress in β cells, which further confirms that KCNH6 protects islets from ER stress and apoptosis. These data suggest that KCNH6 on the ER membrane may help to stabilize intracellular ER Ca2+ stores and protect β cells from ER stress and apoptosis. In conclusion, our study reveals the protective potential of KCNH6-targeting drugs in ER stress-induced diabetes.
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Affiliation(s)
- Feng-Ran Xiong
- Department of Endocrinology, Beijing Diabetes Institute, Beijing Key Laboratory of Diabetes Research and Care, Beijing Tongren Hospital, Capital Medical University, Beijing, China
- Laboratory for Clinical Medicine, Capital Medical University, Beijing, China
| | - Jing Lu
- Department of Endocrinology, Beijing Diabetes Institute, Beijing Key Laboratory of Diabetes Research and Care, Beijing Tongren Hospital, Capital Medical University, Beijing, China
- Laboratory for Clinical Medicine, Capital Medical University, Beijing, China
| | - Juan-Juan Zhu
- Department of Endocrinology, Beijing Diabetes Institute, Beijing Key Laboratory of Diabetes Research and Care, Beijing Tongren Hospital, Capital Medical University, Beijing, China
- Laboratory for Clinical Medicine, Capital Medical University, Beijing, China
| | - Ru-Xuan Zhao
- Department of Endocrinology, Beijing Diabetes Institute, Beijing Key Laboratory of Diabetes Research and Care, Beijing Tongren Hospital, Capital Medical University, Beijing, China
- Laboratory for Clinical Medicine, Capital Medical University, Beijing, China
| | - Ying-Chao Zhang
- Department of Endocrinology, Beijing Diabetes Institute, Beijing Key Laboratory of Diabetes Research and Care, Beijing Tongren Hospital, Capital Medical University, Beijing, China
- Laboratory for Clinical Medicine, Capital Medical University, Beijing, China
| | - Jin-Kui Yang
- Department of Endocrinology, Beijing Diabetes Institute, Beijing Key Laboratory of Diabetes Research and Care, Beijing Tongren Hospital, Capital Medical University, Beijing, China
- Laboratory for Clinical Medicine, Capital Medical University, Beijing, China
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8
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Lee CC, Kono T, Syed F, Weaver SA, Sohn P, Wu W, Chang G, Liu J, Rupnik MS, Evans-Molina C. Histone Deacetylase Inhibitors Prevent Cytokine-Induced β Cell Dysfunction Through Restoration of Stromal Interaction Molecule 1 Expression and Activation of Store-Operated Calcium Entry. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.12.06.570443. [PMID: 38106138 PMCID: PMC10723426 DOI: 10.1101/2023.12.06.570443] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2023]
Abstract
Histone deacetylase inhibitors (HDIs) modulate β cell function in preclinical models of diabetes; however, the mechanisms underlying these beneficial effects have not been determined. In this study, we investigated the impact of the HDI sodium butyrate (NaB) on β cell function and calcium (Ca2+) signaling using ex vivo and in vitro models of diabetes. Our results show that NaB significantly improved glucose-stimulated insulin secretion in islets from human organ donors with type 2 diabetes and in cytokine-treated INS-1 β cells. Consistently, NaB partially rescued glucose-stimulated Ca2+ oscillations in mouse islets treated with proinflammatory cytokines. Because the oscillatory phenotype of Ca2+ in the β cell is governed by changes in endoplasmic reticulum (ER) Ca2+ levels, next we explored the relationship between NaB and store-operated calcium entry (SOCE), a rescue mechanism that acts to refill ER Ca2+ levels through STIM1-mediated gating of plasmalemmal Orai channels. We found that NaB treatment preserved basal ER Ca2+ levels and restored SOCE in IL-1β-treated INS-1 cells. Furthermore, we linked these changes with the restoration of STIM1 levels in cytokine-treated INS-1 cells and mouse islets, and we found that NaB treatment was sufficient to prevent β cell death in response to IL-1β treatment. Mechanistically, NaB counteracted cytokine-mediated reductions in phosphorylation levels of key signaling molecules, including AKT, ERK1/2, glycogen synthase kinase-3α (GSK-3α), and GSK-3β. Taken together, these data support a model whereby HDI treatment promotes β cell function and Ca2+ homeostasis under proinflammatory conditions through STIM1-mediated control of SOCE and AKT-mediated inhibition of GSK-3.
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Affiliation(s)
- Chih-Chun Lee
- Center for Diabetes and Metabolic Diseases, Indiana University School of Medicine, Indianapolis, IN 46202, USA
- Herman B Wells Center for Pediatric Research, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Tatsuyoshi Kono
- Center for Diabetes and Metabolic Diseases, Indiana University School of Medicine, Indianapolis, IN 46202, USA
- Herman B Wells Center for Pediatric Research, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Farooq Syed
- Center for Diabetes and Metabolic Diseases, Indiana University School of Medicine, Indianapolis, IN 46202, USA
- Herman B Wells Center for Pediatric Research, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Staci A. Weaver
- Center for Diabetes and Metabolic Diseases, Indiana University School of Medicine, Indianapolis, IN 46202, USA
- Herman B Wells Center for Pediatric Research, Indiana University School of Medicine, Indianapolis, IN 46202, USA
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Paul Sohn
- Center for Diabetes and Metabolic Diseases, Indiana University School of Medicine, Indianapolis, IN 46202, USA
- Herman B Wells Center for Pediatric Research, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Wenting Wu
- Center for Diabetes and Metabolic Diseases, Indiana University School of Medicine, Indianapolis, IN 46202, USA
- Herman B Wells Center for Pediatric Research, Indiana University School of Medicine, Indianapolis, IN 46202, USA
- Department of Medical & Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Garrick Chang
- Department of Physics, Indiana University Indianapolis, IN 46202, USA
| | - Jing Liu
- Department of Physics and Astronomy, Purdue University, West Lafayette, IN 47907, USA
| | - Marjan Slak Rupnik
- Center for Physiology and Pharmacology, Medical University of Vienna, Austria
- Alma Mater Europaea – European Center Maribor, Slovenia
| | - Carmella Evans-Molina
- Center for Diabetes and Metabolic Diseases, Indiana University School of Medicine, Indianapolis, IN 46202, USA
- Herman B Wells Center for Pediatric Research, Indiana University School of Medicine, Indianapolis, IN 46202, USA
- Department of Pediatrics, Indiana University School of Medicine, Indianapolis, IN 46202, USA
- Department of Medicine, Indiana University School of Medicine, Indianapolis, IN 46202, USA
- Department of Anatomy, Cell Biology, and Physiology, Indiana University School of Medicine, Indianapolis, IN 46202, USA
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, IN 46202, USA
- Richard L. Roudebush VA Medical Center, Indianapolis, IN 46202, USA
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9
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Iida H, Kono T, Lee CC, Krishnan P, Arvin MC, Weaver SA, Jarvela TS, Branco RCS, McLaughlin MR, Bone RN, Tong X, Arvan P, Lindberg I, Evans-Molina C. SERCA2 regulates proinsulin processing and processing enzyme maturation in pancreatic beta cells. Diabetologia 2023; 66:2042-2061. [PMID: 37537395 PMCID: PMC10542743 DOI: 10.1007/s00125-023-05979-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/14/2023] [Accepted: 06/13/2023] [Indexed: 08/05/2023]
Abstract
AIMS/HYPOTHESIS Increased circulating levels of incompletely processed insulin (i.e. proinsulin) are observed clinically in type 1 and type 2 diabetes. Previous studies have suggested that Ca2+ signalling within beta cells regulates insulin processing and secretion; however, the mechanisms that link impaired Ca2+ signalling with defective insulin maturation remain incompletely understood. METHODS We generated mice with beta cell-specific sarcoendoplasmic reticulum Ca2+ ATPase-2 (SERCA2) deletion (βS2KO mice) and used an INS-1 cell line model of SERCA2 deficiency. Whole-body metabolic phenotyping, Ca2+ imaging, RNA-seq and protein processing assays were used to determine how loss of SERCA2 impacts beta cell function. To test key findings in human model systems, cadaveric islets were treated with diabetogenic stressors and prohormone convertase expression patterns were characterised. RESULTS βS2KO mice exhibited age-dependent glucose intolerance and increased plasma and pancreatic levels of proinsulin, while endoplasmic reticulum (ER) Ca2+ levels and glucose-stimulated Ca2+ synchronicity were reduced in βS2KO islets. Islets isolated from βS2KO mice and SERCA2-deficient INS-1 cells showed decreased expression of the active forms of the proinsulin processing enzymes PC1/3 and PC2. Additionally, immunofluorescence staining revealed mis-location and abnormal accumulation of proinsulin and proPC2 in the intermediate region between the ER and the Golgi (i.e. the ERGIC) and in the cis-Golgi in beta cells of βS2KO mice. Treatment of islets from human donors without diabetes with high glucose and palmitate concentrations led to reduced expression of the active forms of the proinsulin processing enzymes, thus phenocopying the findings observed in βS2KO islets and SERCA2-deficient INS-1 cells. Similar findings were observed in wild-type mouse islets treated with brefeldin A, a compound that perturbs ER-to-Golgi trafficking. CONCLUSIONS/INTERPRETATION Taken together, these data highlight an important link between ER Ca2+ homeostasis and proinsulin processing in beta cells. Our findings suggest a model whereby chronic ER Ca2+ depletion due to SERCA2 deficiency impairs the spatial regulation of prohormone trafficking, processing and maturation within the secretory pathway. DATA AVAILABILITY RNA-seq data have been deposited in the Gene Expression Omnibus (GEO; accession no.: GSE207498).
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Affiliation(s)
- Hitoshi Iida
- Department of Medicine, Indiana University School of Medicine, Indianapolis, IN, USA
- Department of Metabolism & Endocrinology, Juntendo University Graduate School of Medicine, Tokyo, Japan
| | - Tatsuyoshi Kono
- Department of Pediatrics, Indiana University School of Medicine, Indianapolis, IN, USA
- Center for Diabetes and Metabolic Diseases, Indiana University School of Medicine, Indianapolis, IN, USA
- Herman B. Wells Center for Pediatric Research, Indiana University School of Medicine, Indianapolis, IN, USA
- Richard L. Roudebush VA Medical Center, Indianapolis, IN, USA
| | - Chih-Chun Lee
- Department of Pediatrics, Indiana University School of Medicine, Indianapolis, IN, USA
- Center for Diabetes and Metabolic Diseases, Indiana University School of Medicine, Indianapolis, IN, USA
- Herman B. Wells Center for Pediatric Research, Indiana University School of Medicine, Indianapolis, IN, USA
- Richard L. Roudebush VA Medical Center, Indianapolis, IN, USA
| | - Preethi Krishnan
- Department of Pediatrics, Indiana University School of Medicine, Indianapolis, IN, USA
- Center for Diabetes and Metabolic Diseases, Indiana University School of Medicine, Indianapolis, IN, USA
- Herman B. Wells Center for Pediatric Research, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Matthew C Arvin
- Department of Pediatrics, Indiana University School of Medicine, Indianapolis, IN, USA
- Center for Diabetes and Metabolic Diseases, Indiana University School of Medicine, Indianapolis, IN, USA
- Herman B. Wells Center for Pediatric Research, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Staci A Weaver
- Center for Diabetes and Metabolic Diseases, Indiana University School of Medicine, Indianapolis, IN, USA
- Herman B. Wells Center for Pediatric Research, Indiana University School of Medicine, Indianapolis, IN, USA
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Timothy S Jarvela
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Renato C S Branco
- Department of Pediatrics, Indiana University School of Medicine, Indianapolis, IN, USA
- Center for Diabetes and Metabolic Diseases, Indiana University School of Medicine, Indianapolis, IN, USA
- Herman B. Wells Center for Pediatric Research, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Madeline R McLaughlin
- Department of Pediatrics, Indiana University School of Medicine, Indianapolis, IN, USA
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN, USA
| | - Robert N Bone
- Department of Pediatrics, Indiana University School of Medicine, Indianapolis, IN, USA
- Center for Diabetes and Metabolic Diseases, Indiana University School of Medicine, Indianapolis, IN, USA
- Herman B. Wells Center for Pediatric Research, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Xin Tong
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN, USA
| | - Peter Arvan
- Division of Metabolism, Endocrinology & Diabetes, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Iris Lindberg
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Carmella Evans-Molina
- Department of Medicine, Indiana University School of Medicine, Indianapolis, IN, USA.
- Department of Pediatrics, Indiana University School of Medicine, Indianapolis, IN, USA.
- Center for Diabetes and Metabolic Diseases, Indiana University School of Medicine, Indianapolis, IN, USA.
- Herman B. Wells Center for Pediatric Research, Indiana University School of Medicine, Indianapolis, IN, USA.
- Richard L. Roudebush VA Medical Center, Indianapolis, IN, USA.
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, IN, USA.
- Department of Anatomy, Cell Biology, and Physiology, Indiana University School of Medicine, Indianapolis, IN, USA.
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10
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Mu-U-Min RBA, Diane A, Allouch A, Al-Siddiqi HH. Ca 2+-Mediated Signaling Pathways: A Promising Target for the Successful Generation of Mature and Functional Stem Cell-Derived Pancreatic Beta Cells In Vitro. Biomedicines 2023; 11:1577. [PMID: 37371672 DOI: 10.3390/biomedicines11061577] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2023] [Revised: 05/18/2023] [Accepted: 05/23/2023] [Indexed: 06/29/2023] Open
Abstract
Diabetes mellitus is a chronic disease affecting over 500 million adults globally and is mainly categorized as type 1 diabetes mellitus (T1DM), where pancreatic beta cells are destroyed, and type 2 diabetes mellitus (T2DM), characterized by beta cell dysfunction. This review highlights the importance of the divalent cation calcium (Ca2+) and its associated signaling pathways in the proper functioning of beta cells and underlines the effects of Ca2+ dysfunction on beta cell function and its implications for the onset of diabetes. Great interest and promise are held by human pluripotent stem cell (hPSC) technology to generate functional pancreatic beta cells from diabetic patient-derived stem cells to replace the dysfunctional cells, thereby compensating for insulin deficiency and reducing the comorbidities of the disease and its associated financial and social burden on the patient and society. Beta-like cells generated by most current differentiation protocols have blunted functionality compared to their adult human counterparts. The Ca2+ dynamics in stem cell-derived beta-like cells and adult beta cells are summarized in this review, revealing the importance of proper Ca2+ homeostasis in beta-cell function. Consequently, the importance of targeting Ca2+ function in differentiation protocols is suggested to improve current strategies to use hPSCs to generate mature and functional beta-like cells with a comparable glucose-stimulated insulin secretion (GSIS) profile to adult beta cells.
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Affiliation(s)
- Razik Bin Abdul Mu-U-Min
- Diabetes Research Center, Qatar Biomedical Research Institute (QBRI), Hamad Bin Khalifa University (HBKU), Qatar Foundation (QF), Doha P.O. Box 34110, Qatar
| | - Abdoulaye Diane
- Diabetes Research Center, Qatar Biomedical Research Institute (QBRI), Hamad Bin Khalifa University (HBKU), Qatar Foundation (QF), Doha P.O. Box 34110, Qatar
| | - Asma Allouch
- Diabetes Research Center, Qatar Biomedical Research Institute (QBRI), Hamad Bin Khalifa University (HBKU), Qatar Foundation (QF), Doha P.O. Box 34110, Qatar
| | - Heba H Al-Siddiqi
- Diabetes Research Center, Qatar Biomedical Research Institute (QBRI), Hamad Bin Khalifa University (HBKU), Qatar Foundation (QF), Doha P.O. Box 34110, Qatar
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11
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Lacombe J, Guo K, Bonneau J, Faubert D, Gioanni F, Vivoli A, Muir SM, Hezzaz S, Poitout V, Ferron M. Vitamin K-dependent carboxylation regulates Ca 2+ flux and adaptation to metabolic stress in β cells. Cell Rep 2023; 42:112500. [PMID: 37171959 DOI: 10.1016/j.celrep.2023.112500] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2022] [Revised: 02/24/2023] [Accepted: 04/26/2023] [Indexed: 05/14/2023] Open
Abstract
Vitamin K is a micronutrient necessary for γ-carboxylation of glutamic acids. This post-translational modification occurs in the endoplasmic reticulum (ER) and affects secreted proteins. Recent clinical studies implicate vitamin K in the pathophysiology of diabetes, but the underlying molecular mechanism remains unknown. Here, we show that mouse β cells lacking γ-carboxylation fail to adapt their insulin secretion in the context of age-related insulin resistance or diet-induced β cell stress. In human islets, γ-carboxylase expression positively correlates with improved insulin secretion in response to glucose. We identify endoplasmic reticulum Gla protein (ERGP) as a γ-carboxylated ER-resident Ca2+-binding protein expressed in β cells. Mechanistically, γ-carboxylation of ERGP protects cells against Ca2+ overfilling by diminishing STIM1 and Orai1 interaction and restraining store-operated Ca2+ entry. These results reveal a critical role of vitamin K-dependent carboxylation in regulation of Ca2+ flux in β cells and in their capacity to adapt to metabolic stress.
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Affiliation(s)
- Julie Lacombe
- Molecular Physiology Research Unit, Institut de Recherches Cliniques de Montréal, Montréal, QC H2W 1R7, Canada.
| | - Kevin Guo
- Molecular Physiology Research Unit, Institut de Recherches Cliniques de Montréal, Montréal, QC H2W 1R7, Canada; Division of Experimental Medicine, McGill University, Montréal, QC H4A 3J1, Canada
| | - Jessica Bonneau
- Molecular Physiology Research Unit, Institut de Recherches Cliniques de Montréal, Montréal, QC H2W 1R7, Canada; Programme de Biologie Moléculaire, Université de Montréal, Montréal, QC H3T 1J4, Canada
| | - Denis Faubert
- Mass Spectrometry and Proteomics Platform, Institut de Recherches Cliniques de Montréal, Montréal, QC H2W 1R7, Canada
| | - Florian Gioanni
- Molecular Physiology Research Unit, Institut de Recherches Cliniques de Montréal, Montréal, QC H2W 1R7, Canada
| | - Alexis Vivoli
- Montreal Diabetes Research Center, Centre de Recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), Montréal, QC H2X 0A9, Canada
| | - Sarah M Muir
- Molecular Physiology Research Unit, Institut de Recherches Cliniques de Montréal, Montréal, QC H2W 1R7, Canada
| | - Soraya Hezzaz
- Molecular Physiology Research Unit, Institut de Recherches Cliniques de Montréal, Montréal, QC H2W 1R7, Canada
| | - Vincent Poitout
- Montreal Diabetes Research Center, Centre de Recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), Montréal, QC H2X 0A9, Canada; Département de Médecine, Université de Montréal, Montréal, QC H3T 1J4, Canada
| | - Mathieu Ferron
- Molecular Physiology Research Unit, Institut de Recherches Cliniques de Montréal, Montréal, QC H2W 1R7, Canada; Division of Experimental Medicine, McGill University, Montréal, QC H4A 3J1, Canada; Programme de Biologie Moléculaire, Université de Montréal, Montréal, QC H3T 1J4, Canada; Département de Médecine, Université de Montréal, Montréal, QC H3T 1J4, Canada.
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12
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Jeyarajan S, Zhang IX, Arvan P, Lentz SI, Satin LS. Simultaneous Measurement of Changes in Mitochondrial and Endoplasmic Reticulum Free Calcium in Pancreatic Beta Cells. BIOSENSORS 2023; 13:382. [PMID: 36979594 PMCID: PMC10046164 DOI: 10.3390/bios13030382] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/26/2023] [Revised: 02/28/2023] [Accepted: 03/08/2023] [Indexed: 05/28/2023]
Abstract
The free calcium (Ca2+) levels in pancreatic beta cell organelles have been the subject of many recent investigations. Under pathophysiological conditions, disturbances in these pools have been linked to altered intracellular communication and cellular dysfunction. To facilitate studies of subcellular Ca2+ signaling in beta cells and, particularly, signaling between the endoplasmic reticulum (ER) and mitochondria, we designed a novel dual Ca2+ sensor which we termed DS-1. DS-1 encodes two stoichiometrically fluorescent proteins within a single plasmid, G-CEPIA-er, targeted to the ER and R-CEPIA3-mt, targeted to mitochondria. Our goal was to simultaneously measure the ER and mitochondrial Ca2+ in cells in real time. The Kds of G-CEPIA-er and R-CEPIA3-mt for Ca2+ are 672 and 3.7 μM, respectively. Confocal imaging of insulin-secreting INS-1 832/13 expressing DS-1 confirmed that the green and red fluorophores correctly colocalized with organelle-specific fluorescent markers as predicted. Further, we tested whether DS-1 exhibited the functional properties expected by challenging an INS-1 cell to glucose concentrations or drugs having well-documented effects on the ER and mitochondrial Ca2+ handling. The data obtained were consistent with those seen using other single organelle targeted probes. These results taken together suggest that DS-1 is a promising new approach for investigating Ca2+ signaling within multiple organelles of the cell.
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Affiliation(s)
- Sivakumar Jeyarajan
- Department of Pharmacology, University of Michigan Medical School, Ann Arbor, MI 48105, USA; (S.J.)
| | - Irina X Zhang
- Department of Pharmacology, University of Michigan Medical School, Ann Arbor, MI 48105, USA; (S.J.)
| | - Peter Arvan
- Department of Internal Medicine, Division of Metabolism, Endocrinology & Diabetes, University of Michigan Medical School, Ann Arbor, MI 48105, USA
- Department of Molecular & Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI 48105, USA
| | - Stephen I. Lentz
- Department of Internal Medicine, Division of Metabolism, Endocrinology & Diabetes, University of Michigan Medical School, Ann Arbor, MI 48105, USA
| | - Leslie S. Satin
- Department of Pharmacology, University of Michigan Medical School, Ann Arbor, MI 48105, USA; (S.J.)
- Department of Internal Medicine, Division of Metabolism, Endocrinology & Diabetes, University of Michigan Medical School, Ann Arbor, MI 48105, USA
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13
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Khajavi N, Beck A, Riçku K, Beyerle P, Jacob K, Syamsul SF, Belkacemi A, Reinach PS, Schreier PC, Salah H, Popp T, Novikoff A, Breit A, Chubanov V, Müller TD, Zierler S, Gudermann T. TRPM7 kinase is required for insulin production and compensatory islet responses during obesity. JCI Insight 2023; 8:163397. [PMID: 36574297 PMCID: PMC9977431 DOI: 10.1172/jci.insight.163397] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2022] [Accepted: 12/21/2022] [Indexed: 12/28/2022] Open
Abstract
Most overweight individuals do not develop diabetes due to compensatory islet responses to restore glucose homeostasis. Therefore, regulatory pathways that promote β cell compensation are potential targets for treatment of diabetes. The transient receptor potential cation channel subfamily M member 7 protein (TRPM7), harboring a cation channel and a serine/threonine kinase, has been implicated in controlling cell growth and proliferation. Here, we report that selective deletion of Trpm7 in β cells disrupted insulin secretion and led to progressive glucose intolerance. We indicate that the diminished insulinotropic response in β cell-specific Trpm7-knockout mice was caused by decreased insulin production because of impaired enzymatic activity of this protein. Accordingly, high-fat-fed mice with a genetic loss of TRPM7 kinase activity displayed a marked glucose intolerance accompanied by hyperglycemia. These detrimental glucoregulatory effects were engendered by reduced compensatory β cell responses because of mitigated protein kinase B (AKT)/ERK signaling. Collectively, our data identify TRPM7 kinase as a potentially novel regulator of insulin synthesis, β cell dynamics, and glucose homeostasis under obesogenic diet.
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Affiliation(s)
- Noushafarin Khajavi
- Walther Straub Institute of Pharmacology and Toxicology, LMU Munich, Munich, Germany
| | - Andreas Beck
- Institute of Experimental and Clinical Pharmacology and Toxicology, Saarland University, Homburg, Germany
| | - Klea Riçku
- Walther Straub Institute of Pharmacology and Toxicology, LMU Munich, Munich, Germany
| | - Philipp Beyerle
- Walther Straub Institute of Pharmacology and Toxicology, LMU Munich, Munich, Germany
| | - Katharina Jacob
- Walther Straub Institute of Pharmacology and Toxicology, LMU Munich, Munich, Germany
| | - Sabrina F. Syamsul
- Walther Straub Institute of Pharmacology and Toxicology, LMU Munich, Munich, Germany
| | - Anouar Belkacemi
- Institute of Experimental and Clinical Pharmacology and Toxicology, Saarland University, Homburg, Germany
| | - Peter S. Reinach
- Wenzhou Medical University, Ophthalmology Department, Wenzhou, China
| | - Pascale C.F. Schreier
- Walther Straub Institute of Pharmacology and Toxicology, LMU Munich, Munich, Germany
| | - Houssein Salah
- Institute of Experimental and Clinical Pharmacology and Toxicology, Saarland University, Homburg, Germany
| | - Tanja Popp
- Bundeswehr Institute of Radiobiology, Munich, Germany
| | - Aaron Novikoff
- Institute of Diabetes and Obesity, Helmholtz Center Munich, Neuherberg, Germany.,German Center for Diabetes Research (DZD), Neuherberg, Germany
| | - Andreas Breit
- Walther Straub Institute of Pharmacology and Toxicology, LMU Munich, Munich, Germany
| | - Vladimir Chubanov
- Walther Straub Institute of Pharmacology and Toxicology, LMU Munich, Munich, Germany
| | - Timo D. Müller
- Institute of Diabetes and Obesity, Helmholtz Center Munich, Neuherberg, Germany.,German Center for Diabetes Research (DZD), Neuherberg, Germany
| | - Susanna Zierler
- Walther Straub Institute of Pharmacology and Toxicology, LMU Munich, Munich, Germany.,Institute of Pharmacology, Medical Faculty, Johannes Kepler University Linz, Linz, Austria
| | - Thomas Gudermann
- Walther Straub Institute of Pharmacology and Toxicology, LMU Munich, Munich, Germany.,German Center for Lung Research, Munich, Germany
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14
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Davidson RK, Weaver SA, Casey N, Kanojia S, Hogarth E, Aguirre RS, Sims EK, Evans-Molina C, Spaeth JM. The Chd4 subunit of the NuRD complex regulates Pdx1-controlled genes involved in β-cell function. J Mol Endocrinol 2022; 69:329-341. [PMID: 35521759 PMCID: PMC9260723 DOI: 10.1530/jme-22-0011] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/08/2022] [Accepted: 05/03/2022] [Indexed: 11/08/2022]
Abstract
Type 2 diabetes (T2D) is associated with loss of transcription factors (TFs) from a subset of failing β-cells. Among these TFs is Pdx1, which controls the expression of numerous genes involved in maintaining β-cell function and identity. Pdx1 activity is modulated by transcriptional coregulators and has recently been shown, through an unbiased screen, to interact with the Chd4 ATPase subunit of the nucleosome remodeling and deacetylase complex. Chd4 contributes to the maintenance of cellular identity and functional status of numerous different cell types. Here, we demonstrated that Pdx1 dynamically interacts with Chd4 under physiological and stimulatory conditions within islet β-cells and established a fundamental role for Chd4 in regulating insulin secretion and modulating numerous Pdx1-bound genes in vitro, including the MafA TF, where we discovered Chd4 is bound to the MafA region 3 enhancer. Furthermore, we found that Pdx1:Chd4 interactions are significantly compromised in islet β-cells under metabolically induced stress in vivo and in human donor tissues with T2D. Our findings establish a fundamental role for Chd4 in regulating insulin secretion and modulating Pdx1-bound genes in vitro, and disruption of Pdx1:Chd4 interactions coincides with β-cell dysfunction associated with T2D.
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Affiliation(s)
- Rebecca K. Davidson
- Department of Biochemistry & Molecular Biology, Indiana University School of Medicine, Indianapolis, Indiana, USA
- Center for Diabetes & Metabolic Diseases, Indiana University School of Medicine, Indianapolis, Indiana, USA
- Herman B. Wells Center for Pediatric Research, Indiana University School of Medicine, Indianapolis, Indiana, USA
| | - Staci A. Weaver
- Department of Biochemistry & Molecular Biology, Indiana University School of Medicine, Indianapolis, Indiana, USA
- Center for Diabetes & Metabolic Diseases, Indiana University School of Medicine, Indianapolis, Indiana, USA
- Herman B. Wells Center for Pediatric Research, Indiana University School of Medicine, Indianapolis, Indiana, USA
| | - Nolan Casey
- Department of Biochemistry & Molecular Biology, Indiana University School of Medicine, Indianapolis, Indiana, USA
- Center for Diabetes & Metabolic Diseases, Indiana University School of Medicine, Indianapolis, Indiana, USA
- Herman B. Wells Center for Pediatric Research, Indiana University School of Medicine, Indianapolis, Indiana, USA
| | - Sukrati Kanojia
- Department of Biochemistry & Molecular Biology, Indiana University School of Medicine, Indianapolis, Indiana, USA
- Center for Diabetes & Metabolic Diseases, Indiana University School of Medicine, Indianapolis, Indiana, USA
- Herman B. Wells Center for Pediatric Research, Indiana University School of Medicine, Indianapolis, Indiana, USA
| | - Elise Hogarth
- Herman B. Wells Center for Pediatric Research, Indiana University School of Medicine, Indianapolis, Indiana, USA
| | - Rebecca Schneider Aguirre
- Center for Diabetes & Metabolic Diseases, Indiana University School of Medicine, Indianapolis, Indiana, USA
- Herman B. Wells Center for Pediatric Research, Indiana University School of Medicine, Indianapolis, Indiana, USA
- Department of Pediatrics, Baylor College of Medicine, Houston, Texas, USA
| | - Emily K. Sims
- Department of Biochemistry & Molecular Biology, Indiana University School of Medicine, Indianapolis, Indiana, USA
- Center for Diabetes & Metabolic Diseases, Indiana University School of Medicine, Indianapolis, Indiana, USA
- Herman B. Wells Center for Pediatric Research, Indiana University School of Medicine, Indianapolis, Indiana, USA
- Department of Pediatrics, Indiana University School of Medicine, Indianapolis, Indiana, USA
| | - Carmella Evans-Molina
- Department of Biochemistry & Molecular Biology, Indiana University School of Medicine, Indianapolis, Indiana, USA
- Center for Diabetes & Metabolic Diseases, Indiana University School of Medicine, Indianapolis, Indiana, USA
- Herman B. Wells Center for Pediatric Research, Indiana University School of Medicine, Indianapolis, Indiana, USA
- Department of Pediatrics, Indiana University School of Medicine, Indianapolis, Indiana, USA
- Richard L. Roudebush VA Medical Center, Indianapolis, Indiana, USA
| | - Jason M. Spaeth
- Department of Biochemistry & Molecular Biology, Indiana University School of Medicine, Indianapolis, Indiana, USA
- Center for Diabetes & Metabolic Diseases, Indiana University School of Medicine, Indianapolis, Indiana, USA
- Herman B. Wells Center for Pediatric Research, Indiana University School of Medicine, Indianapolis, Indiana, USA
- Department of Pediatrics, Indiana University School of Medicine, Indianapolis, Indiana, USA
- Corresponding Author: Address: 635 Barnhill Drive, MS 2021, Indianapolis, IN 46202 (JMS), (JMS)
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15
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Cui X, Zhang Y, Lu Y, Xiang M. ROS and Endoplasmic Reticulum Stress in Pulmonary Disease. Front Pharmacol 2022; 13:879204. [PMID: 35559240 PMCID: PMC9086276 DOI: 10.3389/fphar.2022.879204] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2022] [Accepted: 03/11/2022] [Indexed: 12/25/2022] Open
Abstract
Pulmonary diseases are main causes of morbidity and mortality worldwide. Current studies show that though specific pulmonary diseases and correlative lung-metabolic deviance own unique pathophysiology and clinical manifestations, they always tend to exhibit common characteristics including reactive oxygen species (ROS) signaling and disruptions of proteostasis bringing about accumulation of unfolded or misfolded proteins in the endoplasmic reticulum (ER). ER is generated by the unfolded protein response. When the adaptive unfolded protein response (UPR) fails to preserve ER homeostasis, a maladaptive or terminal UPR is engaged, leading to the disruption of ER integrity and to apoptosis, which is called ER stress. The ER stress mainly includes the accumulation of misfolded and unfolded proteins in lumen and the disorder of Ca2+ balance. ROS mediates several critical aspects of the ER stress response. We summarize the latest advances in of the UPR and ER stress in the pathogenesis of pulmonary disease and discuss potential therapeutic strategies aimed at restoring ER proteostasis in pulmonary disease.
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Affiliation(s)
- Xiangning Cui
- Department of Cardiovascular, Guang'anmen Hospital, China Academy of Chinese Medical Sciences, Beijing, China
| | - Yang Zhang
- First Clinical Medical School, Shandong University of Traditional Chinese Medicine, Jinan, China
| | - Yingdong Lu
- Department of Cardiovascular, Guang'anmen Hospital, China Academy of Chinese Medical Sciences, Beijing, China
| | - Mi Xiang
- Department of Cardiovascular, Guang'anmen Hospital, China Academy of Chinese Medical Sciences, Beijing, China
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16
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Zhang D, Niu S, Ma Y, Chen H, Wen Y, Li M, Zhou B, Deng Y, Shi C, Pu G, Yang M, Wang X, Zou C, Chen Y, Ma L. Fenofibrate Improves Insulin Resistance and Hepatic Steatosis and Regulates the Let-7/SERCA2b Axis in High-Fat Diet-Induced Non-Alcoholic Fatty Liver Disease Mice. Front Pharmacol 2022; 12:770652. [PMID: 35126113 PMCID: PMC8807641 DOI: 10.3389/fphar.2021.770652] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2021] [Accepted: 12/27/2021] [Indexed: 12/20/2022] Open
Abstract
Fenofibrate is widely used in clinical therapy to effectively ameliorate the development of non-alcoholic fatty liver disease (NAFLD); however, its specific molecular mechanism of action remains largely unknown. MicroRNAs (miRNAs) are key mediators in regulating endoplasmic reticulum (ER) stress during NAFLD, and the deregulation of miRNAs has been demonstrated in NAFLD pathophysiology. The present study aimed to identify whether fenofibrate could influence miRNA expression in NAFLD and investigate the specific mechanism of action of fenofibrate in lipid metabolism disorder-associated diseases. We found that fenofibrate alleviated ER stress and increased the levels of SERCA2b, which serves as a regulator of ER stress. Additionally, the levels of let-7 miRNA were regulated by fenofibrate; let-7 was found to target the 3′ untranslated region of SERCA2b. The present data suggest that the protective effects of fenofibrate against insulin resistance and its suppressive activity against excessive hepatic lipid accumulation may be related to the alteration of the let-7/SERCA2b axis and alleviation of ER stress.
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Affiliation(s)
- Dan Zhang
- The First Affiliated Hospital, Yunnan Institute of Digestive Disease, Yunnan Clinical Research Center for Digestive Diseases, Kunming Medical University, Kunming, China
| | - Shanzhuang Niu
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, School of Life Sciences, Yunnan University, Kunming, China
| | - Yicheng Ma
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, School of Life Sciences, Yunnan University, Kunming, China
| | - Hang Chen
- The First Affiliated Hospital, Yunnan Institute of Digestive Disease, Yunnan Clinical Research Center for Digestive Diseases, Kunming Medical University, Kunming, China
| | - Yu Wen
- The First Affiliated Hospital, Yunnan Institute of Digestive Disease, Yunnan Clinical Research Center for Digestive Diseases, Kunming Medical University, Kunming, China
| | - Mingke Li
- The First Affiliated Hospital, Yunnan Institute of Digestive Disease, Yunnan Clinical Research Center for Digestive Diseases, Kunming Medical University, Kunming, China
| | - Bo Zhou
- The First Affiliated Hospital, Yunnan Institute of Digestive Disease, Yunnan Clinical Research Center for Digestive Diseases, Kunming Medical University, Kunming, China
| | - Yi Deng
- The First Affiliated Hospital, Yunnan Institute of Digestive Disease, Yunnan Clinical Research Center for Digestive Diseases, Kunming Medical University, Kunming, China
| | - Chunjing Shi
- The First Affiliated Hospital, Yunnan Institute of Digestive Disease, Yunnan Clinical Research Center for Digestive Diseases, Kunming Medical University, Kunming, China
| | - Guangyu Pu
- The First Affiliated Hospital, Yunnan Institute of Digestive Disease, Yunnan Clinical Research Center for Digestive Diseases, Kunming Medical University, Kunming, China
| | - Meng Yang
- The First Affiliated Hospital, Yunnan Institute of Digestive Disease, Yunnan Clinical Research Center for Digestive Diseases, Kunming Medical University, Kunming, China
| | - Xianmei Wang
- The First Affiliated Hospital, Yunnan Institute of Digestive Disease, Yunnan Clinical Research Center for Digestive Diseases, Kunming Medical University, Kunming, China
| | - Chenggang Zou
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, School of Life Sciences, Yunnan University, Kunming, China
| | - Yuanli Chen
- Faculty of Basic Medicine, Kunming Medical University, Kunming, China
- *Correspondence: Yuanli Chen, ; Lanqing Ma,
| | - Lanqing Ma
- The First Affiliated Hospital, Yunnan Institute of Digestive Disease, Yunnan Clinical Research Center for Digestive Diseases, Kunming Medical University, Kunming, China
- *Correspondence: Yuanli Chen, ; Lanqing Ma,
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17
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Yong J, Johnson JD, Arvan P, Han J, Kaufman RJ. Therapeutic opportunities for pancreatic β-cell ER stress in diabetes mellitus. Nat Rev Endocrinol 2021; 17:455-467. [PMID: 34163039 PMCID: PMC8765009 DOI: 10.1038/s41574-021-00510-4] [Citation(s) in RCA: 142] [Impact Index Per Article: 35.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 05/06/2021] [Indexed: 02/06/2023]
Abstract
Diabetes mellitus is characterized by the failure of insulin-secreting pancreatic β-cells (or β-cell death) due to either autoimmunity (type 1 diabetes mellitus) or failure to compensate for insulin resistance (type 2 diabetes mellitus; T2DM). In addition, mutations of critical genes cause monogenic diabetes. The endoplasmic reticulum (ER) is the primary site for proinsulin folding; therefore, ER proteostasis is crucial for both β-cell function and survival under physiological and pathophysiological challenges. Importantly, the ER is also the major intracellular Ca2+ storage organelle, generating Ca2+ signals that contribute to insulin secretion. ER stress is associated with the pathogenesis of diabetes mellitus. In this Review, we summarize the mutations in monogenic diabetes that play causal roles in promoting ER stress in β-cells. Furthermore, we discuss the possible mechanisms responsible for ER proteostasis imbalance with a focus on T2DM, in which both genetics and environment are considered important in promoting ER stress in β-cells. We also suggest that controlled insulin secretion from β-cells might reduce the progression of a key aspect of the metabolic syndrome, namely nonalcoholic fatty liver disease. Finally, we evaluate potential therapeutic approaches to treat T2DM, including the optimization and protection of functional β-cell mass in individuals with T2DM.
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Affiliation(s)
- Jing Yong
- Degenerative Diseases Program, Sanford-Burnham-Prebys Medical Discovery Institute, La Jolla, CA, USA
| | - James D Johnson
- Department of Cellular and Physiological Sciences & Life Sciences Institute, University of British Columbia, Vancouver, British Columbia, Canada
| | - Peter Arvan
- Division of Metabolism Endocrinology & Diabetes, University of Michigan Medical Center, Ann Arbor, MI, USA
| | - Jaeseok Han
- Soonchunhyang Institute of Medi-bio Science (SIMS), Soonchunhyang University, Cheonan-si, Choongchungnam-do, Republic of Korea.
| | - Randal J Kaufman
- Degenerative Diseases Program, Sanford-Burnham-Prebys Medical Discovery Institute, La Jolla, CA, USA.
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18
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Liu G, Wu F, Wu H, Wang Y, Jiang X, Hu P, Tong X. Inactivation of cysteine 674 in the sarcoplasmic/endoplasmic reticulum calcium ATPase 2 causes retinopathy in the mouse. Exp Eye Res 2021; 207:108559. [PMID: 33848522 DOI: 10.1016/j.exer.2021.108559] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2020] [Revised: 03/01/2021] [Accepted: 03/23/2021] [Indexed: 12/12/2022]
Abstract
Diabetic retinopathy is a multifactorial microvascular complication, and its pathogenesis hasn't been fully elucidated. The irreversible oxidation of cysteine 674 (C674) in the sarcoplasmic/endoplasmic reticulum calcium ATPase 2 (SERCA2) was increased in the type 1 diabetic retinal vasculature. SERCA2 C674S knock-in (SKI) mouse line that half of C674 was replaced by serine 674 (S674) was used to study the effect of C674 inactivation on retinopathy. Compared with wild type (WT) mice, SKI mice had increased number of acellular capillaries and pericyte loss similar to those in type 1 diabetic WT mice. In the retina of SKI mice, pro-apoptotic proteins and intracellular Ca2+-dependent signaling pathways increased, while anti-apoptotic proteins and vessel density decreased. In endothelial cells, C674 inactivation increased the expression of pro-apoptotic proteins, damaged mitochondria, and induced cell apoptosis. These results suggest that a possible mechanism of retinopathy induced by type 1 diabetes is the interruption of calcium homeostasis in the retina by oxidation of C674. C674 is a key to maintain retinal health. Its inactivation can cause retinopathy similar to type 1 diabetes by promoting apoptosis. SERCA2 might be a potential target for the prevention and treatment of diabetic retinopathy.
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Affiliation(s)
- Gang Liu
- Chongqing Key Laboratory of Natural Product Synthesis and Drug Research, School of Pharmaceutical Sciences, Chongqing University, Chongqing, 401331, China; Henan Key Laboratory of Medical Tissue Regeneration, College of Basic Medical Sciences, Xinxiang Medical University, Xinxiang, Henan, 453003, China
| | - Fuhua Wu
- Chongqing Key Laboratory of Natural Product Synthesis and Drug Research, School of Pharmaceutical Sciences, Chongqing University, Chongqing, 401331, China
| | - Haixia Wu
- Chongqing Key Laboratory of Natural Product Synthesis and Drug Research, School of Pharmaceutical Sciences, Chongqing University, Chongqing, 401331, China
| | - Yaping Wang
- Chongqing Key Laboratory of Natural Product Synthesis and Drug Research, School of Pharmaceutical Sciences, Chongqing University, Chongqing, 401331, China
| | - Xiaoli Jiang
- Chongqing Key Laboratory of Natural Product Synthesis and Drug Research, School of Pharmaceutical Sciences, Chongqing University, Chongqing, 401331, China
| | - Pingping Hu
- Chongqing Key Laboratory of Natural Product Synthesis and Drug Research, School of Pharmaceutical Sciences, Chongqing University, Chongqing, 401331, China.
| | - Xiaoyong Tong
- Chongqing Key Laboratory of Natural Product Synthesis and Drug Research, School of Pharmaceutical Sciences, Chongqing University, Chongqing, 401331, China.
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19
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Shrestha N, De Franco E, Arvan P, Cnop M. Pathological β-Cell Endoplasmic Reticulum Stress in Type 2 Diabetes: Current Evidence. Front Endocrinol (Lausanne) 2021; 12:650158. [PMID: 33967960 PMCID: PMC8101261 DOI: 10.3389/fendo.2021.650158] [Citation(s) in RCA: 71] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/06/2021] [Accepted: 04/06/2021] [Indexed: 12/14/2022] Open
Abstract
The notion that in diabetes pancreatic β-cells express endoplasmic reticulum (ER) stress markers indicative of increased unfolded protein response (UPR) signaling is no longer in doubt. However, what remains controversial is whether this increase in ER stress response actually contributes importantly to the β-cell failure of type 2 diabetes (akin to 'terminal UPR'), or whether it represents a coping mechanism that represents the best attempt of β-cells to adapt to changes in metabolic demands as presented by disease progression. Here an intercontinental group of experts review evidence for the role of ER stress in monogenic and type 2 diabetes in an attempt to reconcile these disparate views. Current evidence implies that pancreatic β-cells require a regulated UPR for their development, function and survival, as well as to maintain cellular homeostasis in response to protein misfolding stress. Prolonged ER stress signaling, however, can be detrimental to β-cells, highlighting the importance of "optimal" UPR for ER homeostasis, β-cell function and survival.
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Affiliation(s)
- Neha Shrestha
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI, United States
| | - Elisa De Franco
- Institute of Biomedical and Clinical Science, University of Exeter College of Medicine and Health, Exeter, United Kingdom
| | - Peter Arvan
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI, United States
- Division of Metabolism, Endocrinology & Diabetes, Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, MI, United States
- *Correspondence: Peter Arvan, ; Miriam Cnop,
| | - Miriam Cnop
- ULB Center for Diabetes Research, Medical Faculty, Université Libre de Bruxelles, Brussels, Belgium
- Division of Endocrinology, Erasmus Hospital, Université Libre de Bruxelles, Brussels, Belgium
- *Correspondence: Peter Arvan, ; Miriam Cnop,
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20
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Yao X, Li K, Liang C, Zhou Z, Wang J, Wang S, Liu L, Yu CL, Song ZB, Bao YL, Zheng LH, Sun Y, Wang G, Huang Y, Yi J, Sun L, Li Y. Tectorigenin enhances PDX1 expression and protects pancreatic β-cells by activating ERK and reducing ER stress. J Biol Chem 2020; 295:12975-12992. [PMID: 32690606 DOI: 10.1074/jbc.ra120.012849] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Revised: 07/16/2020] [Indexed: 11/06/2022] Open
Abstract
Pancreas/duodenum homeobox protein 1 (PDX1) is an important transcription factor that regulates islet β-cell proliferation, differentiation, and function. Reduced expression of PDX1 is thought to contribute to β-cell loss and dysfunction in diabetes. Thus, promoting PDX1 expression can be an effective strategy to preserve β-cell mass and function. Previously, we established a PDX1 promoter-dependent luciferase system to screen agents that can promote PDX1 expression. Natural compound tectorigenin (TG) was identified as a promising candidate that could enhance the activity of the promoter for the PDX1 gene. In this study, we first demonstrated that TG could promote the expression of PDX1 in β-cells via activating extracellular signal-related kinase (ERK), as indicated by increased phosphorylation of ERK; this effect was observed under either normal or glucotoxic/lipotoxic conditions. We then found that TG could suppress induced apoptosis and improved the viability of β-cells under glucotoxicity and lipotoxicity by activation of ERK and reduction of reactive oxygen species and endoplasmic reticulum (ER) stress. These effects held true in vivo as well: prophylactic or therapeutic use of TG could obviously inhibit ER stress and decrease islet β-cell apoptosis in the pancreas of mice given a high-fat/high-sucrose diet (HFHSD), thus dramatically maintaining or restoring β-cell mass and islet size, respectively. Accordingly, both prophylactic and therapeutic use of TG improved HFHSD-impaired glucose metabolism in mice, as evidenced by ameliorating hyperglycemia and glucose intolerance. Taken together, TG, as an agent promoting PDX1 expression exhibits strong protective effects on islet β-cells both in vitro and in vivo.
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Affiliation(s)
- Xinlei Yao
- National Engineering Laboratory for Druggable Gene and Protein Screening, Northeast Normal University, Changchun, China; Research Center of Agriculture and Medicine gene Engineering of Ministry of Education, Northeast Normal University, Changchun, China
| | - Kun Li
- National Engineering Laboratory for Druggable Gene and Protein Screening, Northeast Normal University, Changchun, China
| | - Chen Liang
- National Engineering Laboratory for Druggable Gene and Protein Screening, Northeast Normal University, Changchun, China
| | - Zilong Zhou
- National Engineering Laboratory for Druggable Gene and Protein Screening, Northeast Normal University, Changchun, China
| | - Jiao Wang
- Research Center of Agriculture and Medicine gene Engineering of Ministry of Education, Northeast Normal University, Changchun, China
| | - Shuyue Wang
- Research Center of Agriculture and Medicine gene Engineering of Ministry of Education, Northeast Normal University, Changchun, China
| | - Lei Liu
- Research Center of Agriculture and Medicine gene Engineering of Ministry of Education, Northeast Normal University, Changchun, China
| | - Chun-Lei Yu
- National Engineering Laboratory for Druggable Gene and Protein Screening, Northeast Normal University, Changchun, China
| | - Zhen-Bo Song
- Research Center of Agriculture and Medicine gene Engineering of Ministry of Education, Northeast Normal University, Changchun, China
| | - Yong-Li Bao
- National Engineering Laboratory for Druggable Gene and Protein Screening, Northeast Normal University, Changchun, China
| | - Li-Hua Zheng
- National Engineering Laboratory for Druggable Gene and Protein Screening, Northeast Normal University, Changchun, China
| | - Ying Sun
- Research Center of Agriculture and Medicine gene Engineering of Ministry of Education, Northeast Normal University, Changchun, China
| | - Guannan Wang
- Research Center of Agriculture and Medicine gene Engineering of Ministry of Education, Northeast Normal University, Changchun, China
| | - Yanxin Huang
- National Engineering Laboratory for Druggable Gene and Protein Screening, Northeast Normal University, Changchun, China
| | - Jingwen Yi
- Research Center of Agriculture and Medicine gene Engineering of Ministry of Education, Northeast Normal University, Changchun, China
| | - Luguo Sun
- National Engineering Laboratory for Druggable Gene and Protein Screening, Northeast Normal University, Changchun, China.
| | - Yuxin Li
- Research Center of Agriculture and Medicine gene Engineering of Ministry of Education, Northeast Normal University, Changchun, China.
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21
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Zhang IX, Ren J, Vadrevu S, Raghavan M, Satin LS. ER stress increases store-operated Ca 2+ entry (SOCE) and augments basal insulin secretion in pancreatic beta cells. J Biol Chem 2020; 295:5685-5700. [PMID: 32179650 PMCID: PMC7186166 DOI: 10.1074/jbc.ra120.012721] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2020] [Revised: 03/06/2020] [Indexed: 12/13/2022] Open
Abstract
Type 2 diabetes mellitus (T2DM) is characterized by impaired glucose-stimulated insulin secretion and increased peripheral insulin resistance. Unremitting endoplasmic reticulum (ER) stress can lead to beta-cell apoptosis and has been linked to type 2 diabetes. Although many studies have attempted to link ER stress and T2DM, the specific effects of ER stress on beta-cell function remain incompletely understood. To determine the interrelationship between ER stress and beta-cell function, here we treated insulin-secreting INS-1(832/13) cells or isolated mouse islets with the ER stress-inducer tunicamycin (TM). TM induced ER stress as expected, as evidenced by activation of the unfolded protein response. Beta cells treated with TM also exhibited concomitant alterations in their electrical activity and cytosolic free Ca2+ oscillations. As ER stress is known to reduce ER Ca2+ levels, we tested the hypothesis that the observed increase in Ca2+ oscillations occurred because of reduced ER Ca2+ levels and, in turn, increased store-operated Ca2+ entry. TM-induced cytosolic Ca2+ and membrane electrical oscillations were acutely inhibited by YM58483, which blocks store-operated Ca2+ channels. Significantly, TM-treated cells secreted increased insulin under conditions normally associated with only minimal release, e.g. 5 mm glucose, and YM58483 blocked this secretion. Taken together, these results support a critical role for ER Ca2+ depletion-activated Ca2+ current in mediating Ca2+-induced insulin secretion in response to ER stress.
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Affiliation(s)
- Irina X Zhang
- Department of Pharmacology and Brehm Diabetes Research Center, University of Michigan Medical School, Ann Arbor, Michigan 48105
| | - Jianhua Ren
- Department of Pharmacology and Brehm Diabetes Research Center, University of Michigan Medical School, Ann Arbor, Michigan 48105
| | | | - Malini Raghavan
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, Michigan 48109
| | - Leslie S Satin
- Department of Pharmacology and Brehm Diabetes Research Center, University of Michigan Medical School, Ann Arbor, Michigan 48105.
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22
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Karunakaran U, Lee JE, Elumalai S, Moon JS, Won KC. Myricetin prevents thapsigargin-induced CDK5-P66Shc signalosome mediated pancreatic β-cell dysfunction. Free Radic Biol Med 2019; 141:59-66. [PMID: 31163256 DOI: 10.1016/j.freeradbiomed.2019.05.038] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/18/2019] [Revised: 05/30/2019] [Accepted: 05/31/2019] [Indexed: 12/18/2022]
Abstract
Chronic endoplasmic reticulum (ER) stress has deleterious effects on pancreatic β-cell function and survival in type 2 diabetes (T2D). Cyclin-dependent kinase 5 (CDK5) plays a critical role in β-cell failure under diabetic milieu conditions. However, little information is available on CDK5's ability to impair the function of β-cells via a chemical ER stress inducer thapsigargin. Myricetin, a natural flavonoid, has therapeutic potential for the treatment of type 2 diabetes mellitus. Therefore, we examined the effect of CDK5 on thapsigargin-induced β-cell apoptosis, and explored the relationship between myricetin and CDK5. Exposure of beta cells with thapsigargin, induced a Src-mediated redox signaling (VAV2-Rac1-NOX) formation and CDK5 activation. Activated CDK5 induced antiapoptotic protein myeloid cell leukemia sequence 1 (Mcl-1) degradation which was associated with p66Shc serine 36 phosphorylation, causing beta cell apoptosis via mitochondrial dysfunction. Exposure of beta cells to myricetin resulted in an acute inhibition of Src-mediated redox signaling (VAV2-Rac1-NOX) formation and CDK5 activation. Myricetin inhibited CDK5 activation by directly binding to its ATP-binding pocket. Treatment with myricetin also enhanced the stability of Mcl-1 after thapsigargin treatment. Inhibition of CDK5 with myricetin or roscovitine, a CDK5 inhibitor attenuates thapsigargin induced p66Shc serine 36 phosphorylation and also reduced mitochondrial dysfunction by decreasing mitochondrial ROS and caspase-3 activation. In addition, myricetin was observed to enhance PDX-1 and insulin mRNA expression and potentiate glucose stimulated insulin secretion (GSIS). Taken together, these findings indicate that thapsigargin-induced early molecular events lead to CDK5-p66Shc signalosome contributes to thapsigargin-induced pancreatic β-cell dysfunction. Myricetin blocked thapsigargin induced CDK5-p66Shc signalosome formation and prevented pancreatic beta cell dysfunction. In this study, we demonstrated for the first time that thapsigargin initiated CDK5-p66Shc signalosome mediates the pancreatic beta cell dysfunction and myricetin protects the pancreatic beta cells through the inhibition of CDK5-p66Shc signalosome.
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Affiliation(s)
- Udayakumar Karunakaran
- Department of Internal Medicine, Yeungnam University College of Medicine, Daegu, Republic of Korea
| | - Ji Eun Lee
- Department of Internal Medicine, CHA Gumi Medical Center, CHA University, Gumi, Republic of Korea
| | - Suma Elumalai
- Institute of Medical Science, Yeungnam University College of Medicine, Daegu, Republic of Korea
| | - Jun Sung Moon
- Department of Internal Medicine, Yeungnam University College of Medicine, Daegu, Republic of Korea.
| | - Kyu Chang Won
- Department of Internal Medicine, Yeungnam University College of Medicine, Daegu, Republic of Korea; Institute of Medical Science, Yeungnam University College of Medicine, Daegu, Republic of Korea.
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23
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Karunakaran U, Elumalai S, Moon JS, Jeon JH, Kim ND, Park KG, Won KC, Leem J, Lee IK. Myricetin Protects Against High Glucose-Induced β-Cell Apoptosis by Attenuating Endoplasmic Reticulum Stress via Inactivation of Cyclin-Dependent Kinase 5. Diabetes Metab J 2019; 43:192-205. [PMID: 30688049 PMCID: PMC6470101 DOI: 10.4093/dmj.2018.0052] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/26/2018] [Accepted: 07/16/2018] [Indexed: 11/08/2022] Open
Abstract
BACKGROUND Chronic hyperglycemia has deleterious effects on pancreatic β-cell function and turnover. Recent studies support the view that cyclin-dependent kinase 5 (CDK5) plays a role in β-cell failure under hyperglycemic conditions. However, little is known about how CDK5 impair β-cell function. Myricetin, a natural flavonoid, has therapeutic potential for the treatment of type 2 diabetes mellitus. In this study, we examined the effect of myricetin on high glucose (HG)-induced β-cell apoptosis and explored the relationship between myricetin and CDK5. METHODS To address this question, we subjected INS-1 cells and isolated rat islets to HG conditions (30 mM) in the presence or absence of myricetin. Docking studies were conducted to validate the interaction between myricetin and CDK5. Gene expression and protein levels of endoplasmic reticulum (ER) stress markers were measured by real-time reverse transcription polymerase chain reaction and Western blot analysis. RESULTS Activation of CDK5 in response to HG coupled with the induction of ER stress via the down regulation of sarcoendoplasmic reticulum calcium ATPase 2b (SERCA2b) gene expression and reduced the nuclear accumulation of pancreatic duodenal homeobox 1 (PDX1) leads to β-cell apoptosis. Docking study predicts that myricetin inhibit CDK5 activation by direct binding in the ATP-binding pocket. Myricetin counteracted the decrease in the levels of PDX1 and SERCA2b by HG. Moreover, myricetin attenuated HG-induced apoptosis in INS-1 cells and rat islets and reduce the mitochondrial dysfunction by decreasing reactive oxygen species production and mitochondrial membrane potential (ΔΨm) loss. CONCLUSION Myricetin protects the β-cells against HG-induced apoptosis by inhibiting ER stress, possibly through inactivation of CDK5 and consequent upregulation of PDX1 and SERCA2b.
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Affiliation(s)
- Udayakumar Karunakaran
- Department of Biomedical Science, Graduate School of Medicine, Kyungpook National University, Daegu, Korea
- Department of Internal Medicine, Yeungnam University College of Medicine, Daegu, Korea
| | - Suma Elumalai
- Institute of Medical Science, Yeungnam University College of Medicine, Daegu, Korea
| | - Jun Sung Moon
- Department of Internal Medicine, Yeungnam University College of Medicine, Daegu, Korea
| | - Jae Han Jeon
- Department of Internal Medicine, School of Medicine, Kyungpook National University, Kyungpook National University Hospital, Daegu, Korea
| | - Nam Doo Kim
- New Drug Development Center, Daegu-Gyeongbuk Medical Innovation Foundation, Daegu, Korea
| | - Keun Gyu Park
- Department of Internal Medicine, School of Medicine, Kyungpook National University, Kyungpook National University Hospital, Daegu, Korea
| | - Kyu Chang Won
- Department of Internal Medicine, Yeungnam University College of Medicine, Daegu, Korea
| | - Jaechan Leem
- Department of Immunology, School of Medicine, Catholic University of Daegu, Daegu, Korea.
| | - In Kyu Lee
- Department of Internal Medicine, School of Medicine, Kyungpook National University, Kyungpook National University Hospital, Daegu, Korea.
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24
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Effects of Huanglian-Renshen-Decoction, a Fixed Mixture of Traditional Chinese Medicine, on the Improvement of Glucose Metabolism by Maintenance of Pancreatic β Cell Identity in db/db Mice. EVIDENCE-BASED COMPLEMENTARY AND ALTERNATIVE MEDICINE 2019; 2019:1232913. [PMID: 31015847 PMCID: PMC6444265 DOI: 10.1155/2019/1232913] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/11/2018] [Revised: 01/10/2019] [Accepted: 01/27/2019] [Indexed: 02/07/2023]
Abstract
Huanglian-Renshen-Decoction (HRD) is widely used to treat type 2 diabetes mellitus (T2DM) in China. However, the underlying mechanism is unclear. We aimed to investigate the mechanism by which HRD regulates the glucose level. Forty 7-8-week-old db/db (BSK) mice were randomly assigned to the following four groups: model, low dose HRD (LHRD), high dose HRD (HHRD), and saxagliptin (SAX). Additionally, 10 db/m mice were assigned to control group. The experimental mice were administered 3.03g/kg/d and 6.06g/kg/d of HRD in the LHRD and HHRD groups, respectively, and 10mg/kg/d saxagliptin in the SAX group for 8 weeks. The control and model groups were supplied with distilled water. After the intervention, the pancreas and blood were collected and tested. Compared with that of model group, the fasting blood glucose (FBG) was significantly decreased in all intervention groups (p < 0.05 or 0.01), whereas fasting serum insulin (FINS) was increased significantly in both HHRD and SAX groups. The immunofluorescence images showed that the mass of insulin+ cells was increased and that of glucagon+ cells was reduced obviously in experimental groups compared to those of the model group. In addition, the coexpression of insulin, glucagon, and PDX1 was decreased in HHRD group, and the level of caspase 12 in islet was decreased significantly in all intervention groups. However, little difference was found in the number and morphology of islet, and the expression of ki67, bcl2, bax, caspase 3, and cleaved-caspase 3 in the pancreas among groups. Interestingly, the cleaved-Notch1 level was increased and the Ngn3 level in islet was decreased significantly in HHRD group. The HRD showed dose-dependent effects on glucose metabolism improvement through maintenance of β cell identity via a mechanism that might involve the Notch1/Ngn3 signal pathway in db/db mice.
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25
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Yamamoto WR, Bone RN, Sohn P, Syed F, Reissaus CA, Mosley AL, Wijeratne AB, True JD, Tong X, Kono T, Evans-Molina C. Endoplasmic reticulum stress alters ryanodine receptor function in the murine pancreatic β cell. J Biol Chem 2019; 294:168-181. [PMID: 30420428 PMCID: PMC6322901 DOI: 10.1074/jbc.ra118.005683] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2018] [Revised: 11/08/2018] [Indexed: 01/23/2023] Open
Abstract
Alterations in endoplasmic reticulum (ER) calcium (Ca2+) levels diminish insulin secretion and reduce β-cell survival in both major forms of diabetes. The mechanisms responsible for ER Ca2+ loss in β cells remain incompletely understood. Moreover, a specific role for either ryanodine receptor (RyR) or inositol 1,4,5-triphosphate receptor (IP3R) dysfunction in the pathophysiology of diabetes remains largely untested. To this end, here we applied intracellular and ER Ca2+ imaging techniques in INS-1 β cells and isolated islets to determine whether diabetogenic stressors alter RyR or IP3R function. Our results revealed that the RyR is sensitive mainly to ER stress-induced dysfunction, whereas cytokine stress specifically alters IP3R activity. Consistent with this observation, pharmacological inhibition of the RyR with ryanodine and inhibition of the IP3R with xestospongin C prevented ER Ca2+ loss under ER and cytokine stress conditions, respectively. However, RyR blockade distinctly prevented β-cell death, propagation of the unfolded protein response (UPR), and dysfunctional glucose-induced Ca2+ oscillations in tunicamycin-treated INS-1 β cells and mouse islets and Akita islets. Monitoring at the single-cell level revealed that ER stress acutely increases the frequency of intracellular Ca2+ transients that depend on both ER Ca2+ leakage from the RyR and plasma membrane depolarization. Collectively, these findings indicate that RyR dysfunction shapes ER Ca2+ dynamics in β cells and regulates both UPR activation and cell death, suggesting that RyR-mediated loss of ER Ca2+ may be an early pathogenic event in diabetes.
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Affiliation(s)
- Wataru R Yamamoto
- Departments of Cellular and Integrative Physiology, Indiana University School of Medicine, Indianapolis, Indiana 46202
| | - Robert N Bone
- Department of Medicine, Indiana University School of Medicine, Indianapolis, Indiana 46202
| | - Paul Sohn
- Departments of Cellular and Integrative Physiology, Indiana University School of Medicine, Indianapolis, Indiana 46202
| | - Farooq Syed
- Herman B. Wells Center for Pediatric Research, Indiana University School of Medicine, Indianapolis, Indiana 46202
| | - Christopher A Reissaus
- Herman B. Wells Center for Pediatric Research, Indiana University School of Medicine, Indianapolis, Indiana 46202
| | - Amber L Mosley
- Departments of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, Indiana 46202
| | - Aruna B Wijeratne
- Departments of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, Indiana 46202
| | - Jason D True
- Departments of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, Indiana 46202
| | - Xin Tong
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, Tennessee 37235
| | - Tatsuyoshi Kono
- Department of Medicine, Indiana University School of Medicine, Indianapolis, Indiana 46202
| | - Carmella Evans-Molina
- Departments of Cellular and Integrative Physiology, Indiana University School of Medicine, Indianapolis, Indiana 46202; Department of Medicine, Indiana University School of Medicine, Indianapolis, Indiana 46202; Departments of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, Indiana 46202; Herman B. Wells Center for Pediatric Research, Indiana University School of Medicine, Indianapolis, Indiana 46202; Roudebush Veterans Affairs Medical Center, Indianapolis, Indiana 46202.
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Kono T, Tong X, Taleb S, Bone RN, Iida H, Lee CC, Sohn P, Gilon P, Roe MW, Evans-Molina C. Impaired Store-Operated Calcium Entry and STIM1 Loss Lead to Reduced Insulin Secretion and Increased Endoplasmic Reticulum Stress in the Diabetic β-Cell. Diabetes 2018; 67:2293-2304. [PMID: 30131394 PMCID: PMC6198337 DOI: 10.2337/db17-1351] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/09/2017] [Accepted: 08/08/2018] [Indexed: 12/24/2022]
Abstract
Store-operated Ca2+ entry (SOCE) is a dynamic process that leads to refilling of endoplasmic reticulum (ER) Ca2+ stores through reversible gating of plasma membrane Ca2+ channels by the ER Ca2+ sensor Stromal Interaction Molecule 1 (STIM1). Pathogenic reductions in β-cell ER Ca2+ have been observed in diabetes. However, a role for impaired SOCE in this phenotype has not been tested. We measured the expression of SOCE molecular components in human and rodent models of diabetes and found a specific reduction in STIM1 mRNA and protein levels in human islets from donors with type 2 diabetes (T2D), islets from hyperglycemic streptozotocin-treated mice, and INS-1 cells (rat insulinoma cells) treated with proinflammatory cytokines and palmitate. Pharmacologic SOCE inhibitors led to impaired islet Ca2+ oscillations and insulin secretion, and these effects were phenocopied by β-cell STIM1 deletion. STIM1 deletion also led to reduced ER Ca2+ storage and increased ER stress, whereas STIM1 gain of function rescued β-cell survival under proinflammatory conditions and improved insulin secretion in human islets from donors with T2D. Taken together, these data suggest that the loss of STIM1 and impaired SOCE contribute to ER Ca2+ dyshomeostasis under diabetic conditions, whereas efforts to restore SOCE-mediated Ca2+ transients may have the potential to improve β-cell health and function.
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Affiliation(s)
- Tatsuyoshi Kono
- Department of Medicine, Indiana University School of Medicine, Indianapolis, IN
- Richard L. Roudebush VA Medical Center, Indianapolis, IN
| | - Xin Tong
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN
| | - Solaema Taleb
- Department of Medicine, Indiana University School of Medicine, Indianapolis, IN
| | - Robert N Bone
- Department of Medicine, Indiana University School of Medicine, Indianapolis, IN
| | - Hitoshi Iida
- Department of Medicine, Indiana University School of Medicine, Indianapolis, IN
| | - Chih-Chun Lee
- Department of Medicine, Indiana University School of Medicine, Indianapolis, IN
| | - Paul Sohn
- Department of Cellular and Integrative Physiology, Indiana University School of Medicine, Indianapolis, IN
| | - Patrick Gilon
- Pôle d'endocrinologie, diabète et nutrition, Institut de recherche expérimentale et clinique, Université catholique de Louvain, Brussels, Belgium
| | - Michael W Roe
- Department of Medicine, SUNY Upstate Medical University, Syracuse, NY
| | - Carmella Evans-Molina
- Department of Medicine, Indiana University School of Medicine, Indianapolis, IN
- Richard L. Roudebush VA Medical Center, Indianapolis, IN
- Department of Cellular and Integrative Physiology, Indiana University School of Medicine, Indianapolis, IN
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, IN
- Herman B Wells Center for Pediatric Research, Indiana University School of Medicine, Indianapolis, IN
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Abstract
PURPOSE OF REVIEW To discuss advances in our understanding of beta-cell heterogeneity and the ramifications of this for type 1 diabetes (T1D) and its therapy. RECENT FINDINGS A number of studies have challenged the long-standing dogma that the majority of beta cells are eliminated in T1D. As many as 80% are present in some T1D subjects. Why don't these cells function properly to release insulin in response to high glucose? Other findings deploying single-cell "omics" to study both healthy and diseased cells-from patients with both T1D and type 2 diabetes (T2D)-have revealed cell subpopulations and heterogeneity at the transcriptomic/protein level between individual cells. Finally, our own and others' findings have demonstrated the importance of functional beta-cell subpopulations for insulin secretion. Heterogeneity may endow beta cells with molecular features that predispose them to failure/death during T1D.
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Affiliation(s)
- Richard K. P. Benninger
- 0000 0001 0703 675Xgrid.430503.1Department of Bioengineering, University of Colorado Anschutz Medical Campus, Aurora, CO 80045 USA
- 0000 0001 0703 675Xgrid.430503.1Barbara Davis Center for Childhood Diabetes, University of Colorado Anschutz Medical Campus, Aurora, CO 80045 USA
| | - Craig Dorrell
- 0000 0000 9758 5690grid.5288.7Oregon Stem Cell Center, Papé Family Pediatric Research Institute, Department of Pediatrics, Oregon Health and Science University, 3181 SW Sam Jackson Park Road, Portland, OR 97239 USA
| | - David J. Hodson
- 0000 0004 1936 7486grid.6572.6Institute of Metabolism and Systems Research (IMSR), University of Birmingham, Birmingham, B15 2TT UK
- Centre for Endocrinology, Diabetes and Metabolism, Birmingham Health Partners, Birmingham, B15 2TH UK
- COMPARE, University of Birmingham and University of Nottingham Midlands, Nottingham, UK
| | - Guy A. Rutter
- 0000 0001 2113 8111grid.7445.2Section of Cell Biology and Functional Genomics, Department of Medicine, Imperial College London, London, W12 0NN UK
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Nasteska D, Hodson DJ. The role of beta cell heterogeneity in islet function and insulin release. J Mol Endocrinol 2018; 61:R43-R60. [PMID: 29661799 PMCID: PMC5976077 DOI: 10.1530/jme-18-0011] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/13/2018] [Accepted: 04/16/2018] [Indexed: 12/15/2022]
Abstract
It is becoming increasingly apparent that not all insulin-secreting beta cells are equal. Subtle differences exist at the transcriptomic and protein expression levels, with repercussions for beta cell survival/proliferation, calcium signalling and insulin release. Notably, beta cell heterogeneity displays plasticity during development, metabolic stress and type 2 diabetes mellitus (T2DM). Thus, heterogeneity or lack thereof may be an important contributor to beta cell failure during T2DM in both rodents and humans. The present review will discuss the molecular and cellular features of beta cell heterogeneity at both the single-cell and islet level, explore how this influences islet function and insulin release and look into the alterations that may occur during obesity and T2DM.
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Affiliation(s)
- Daniela Nasteska
- Institute of Metabolism and Systems Research (IMSR)University of Birmingham, Edgbaston, UK
- Centre for EndocrinologyDiabetes and Metabolism, Birmingham Health Partners, Birmingham, UK
- COMPARE University of Birmingham and University of Nottingham MidlandsBirmingham, UK
| | - David J Hodson
- Institute of Metabolism and Systems Research (IMSR)University of Birmingham, Edgbaston, UK
- Centre for EndocrinologyDiabetes and Metabolism, Birmingham Health Partners, Birmingham, UK
- COMPARE University of Birmingham and University of Nottingham MidlandsBirmingham, UK
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Benninger RKP, Hodson DJ. New Understanding of β-Cell Heterogeneity and In Situ Islet Function. Diabetes 2018; 67:537-547. [PMID: 29559510 PMCID: PMC5860861 DOI: 10.2337/dbi17-0040] [Citation(s) in RCA: 105] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/28/2017] [Accepted: 12/28/2017] [Indexed: 12/25/2022]
Abstract
Insulin-secreting β-cells are heterogeneous in their regulation of hormone release. While long known, recent technological advances and new markers have allowed the identification of novel subpopulations, improving our understanding of the molecular basis for heterogeneity. This includes specific subpopulations with distinct functional characteristics, developmental programs, abilities to proliferate in response to metabolic or developmental cues, and resistance to immune-mediated damage. Importantly, these subpopulations change in disease or aging, including in human disease. Although discovering new β-cell subpopulations has substantially advanced our understanding of islet biology, a point of caution is that these characteristics have often necessarily been identified in single β-cells dissociated from the islet. β-Cells in the islet show extensive communication with each other via gap junctions and with other cell types via diffusible chemical messengers. As such, how these different subpopulations contribute to in situ islet function, including during plasticity, is not well understood. We will discuss recent findings revealing functional β-cell subpopulations in the intact islet, the underlying basis for these identified subpopulations, and how these subpopulations may influence in situ islet function. Furthermore, we will discuss the outlook for emerging technologies to gain further insight into the role of subpopulations in in situ islet function.
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Affiliation(s)
- Richard K P Benninger
- Department of Bioengineering, University of Colorado Anschutz Medical Campus, Aurora, CO
- Barbara Davis Center for Diabetes, University of Colorado Anschutz Medical Campus, Aurora, CO
| | - David J Hodson
- Institute of Metabolism and Systems Research, University of Birmingham, Birmingham, U.K.
- Centre for Endocrinology, Diabetes and Metabolism, Birmingham Health Partners, Birmingham, U.K
- Centre of Membrane Proteins and Receptors (COMPARE), University of Birmingham and University of Nottingham, Birmingham, U.K
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30
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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: 54] [Impact Index Per Article: 7.7] [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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Vierra NC, Dadi PK, Milian SC, Dickerson MT, Jordan KL, Gilon P, Jacobson DA. TALK-1 channels control β cell endoplasmic reticulum Ca 2+ homeostasis. Sci Signal 2017; 10:eaan2883. [PMID: 28928238 PMCID: PMC5672804 DOI: 10.1126/scisignal.aan2883] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Ca2+ handling by the endoplasmic reticulum (ER) serves critical roles in controlling pancreatic β cell function and becomes perturbed during the pathogenesis of diabetes. ER Ca2+ homeostasis is determined by ion movements across the ER membrane, including K+ flux through K+ channels. We demonstrated that K+ flux through ER-localized TALK-1 channels facilitated Ca2+ release from the ER in mouse and human β cells. We found that β cells from mice lacking TALK-1 exhibited reduced basal cytosolic Ca2+ and increased ER Ca2+ concentrations, suggesting reduced ER Ca2+ leak. These changes in Ca2+ homeostasis were presumably due to TALK-1-mediated ER K+ flux, because we recorded K+ currents mediated by functional TALK-1 channels on the nuclear membrane, which is continuous with the ER. Moreover, overexpression of K+-impermeable TALK-1 channels in HEK293 cells did not reduce ER Ca2+ stores. Reduced ER Ca2+ content in β cells is associated with ER stress and islet dysfunction in diabetes, and islets from TALK-1-deficient mice fed a high-fat diet showed reduced signs of ER stress, suggesting that TALK-1 activity exacerbated ER stress. Our data establish TALK-1 channels as key regulators of β cell ER Ca2+ and suggest that TALK-1 may be a therapeutic target to reduce ER Ca2+ handling defects in β cells during the pathogenesis of diabetes.
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Affiliation(s)
- Nicholas C Vierra
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN 37232, USA
| | - Prasanna K Dadi
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN 37232, USA
| | - Sarah C Milian
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN 37232, USA
| | - Matthew T Dickerson
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN 37232, USA
| | - Kelli L Jordan
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN 37232, USA
| | - Patrick Gilon
- Pôle d'endocrinologie, diabète et nutrition, Institut de recherche expérimentale et clinique, Université catholique de Louvain, Brussels 1200, Belgium
| | - David A Jacobson
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN 37232, USA.
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32
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Alejandro EU, Bozadjieva N, Blandino-Rosano M, Wasan MA, Elghazi L, Vadrevu S, Satin L, Bernal-Mizrachi E. Overexpression of Kinase-Dead mTOR Impairs Glucose Homeostasis by Regulating Insulin Secretion and Not β-Cell Mass. Diabetes 2017; 66:2150-2162. [PMID: 28546423 PMCID: PMC5521866 DOI: 10.2337/db16-1349] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/03/2016] [Accepted: 05/01/2017] [Indexed: 12/20/2022]
Abstract
Regulation of glucose homeostasis by insulin depends on β-cell growth and function. Nutrients and growth factor stimuli converge on the conserved protein kinase mechanistic target of rapamycin (mTOR), existing in two complexes, mTORC1 and mTORC2. To understand the functional relevance of mTOR enzymatic activity in β-cell development and glucose homeostasis, we generated mice overexpressing either one or two copies of a kinase-dead mTOR mutant (KD-mTOR) transgene exclusively in β-cells. We examined glucose homeostasis and β-cell function of these mice fed a control chow or high-fat diet. Mice with two copies of the transgene [RIPCre;KD-mTOR (Homozygous)] develop glucose intolerance due to a defect in β-cell function without alterations in β-cell mass with control chow. Islets from RIPCre;KD-mTOR (Homozygous) mice showed reduced mTORC1 and mTORC2 signaling along with transcripts and protein levels of Pdx-1. Islets with reduced mTORC2 signaling in their β-cells (RIPCre;Rictorfl/fl) also showed reduced Pdx-1. When challenged with a high-fat diet, mice carrying one copy of KD-mTOR mutant transgene developed glucose intolerance and β-cell insulin secretion defect but showed no changes in β-cell mass. These findings suggest that the mTOR-mediated signaling pathway is not essential to β-cell growth but is involved in regulating β-cell function in normal and diabetogenic conditions.
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Affiliation(s)
- Emilyn U Alejandro
- Division of Metabolism, Endocrinology & Diabetes, Department of Internal Medicine, University of Michigan, Ann Arbor, MI
- Department of Integrative Biology and Physiology, University of Minnesota, Minneapolis, MN
| | - Nadejda Bozadjieva
- Division of Metabolism, Endocrinology & Diabetes, Department of Internal Medicine, University of Michigan, Ann Arbor, MI
| | - Manuel Blandino-Rosano
- Division of Metabolism, Endocrinology & Diabetes, Department of Internal Medicine, University of Michigan, Ann Arbor, MI
- Division of Endocrinology, Metabolism and Diabetes, University of Miami, Miami, FL
| | - Michelle Ann Wasan
- Department of Integrative Biology and Physiology, University of Minnesota, Minneapolis, MN
| | - Lynda Elghazi
- Division of Metabolism, Endocrinology & Diabetes, Department of Internal Medicine, University of Michigan, Ann Arbor, MI
| | | | - Leslie Satin
- Department of Pharmacology, University of Michigan, Ann Arbor, MI
| | - Ernesto Bernal-Mizrachi
- Division of Metabolism, Endocrinology & Diabetes, Department of Internal Medicine, University of Michigan, Ann Arbor, MI
- Division of Endocrinology, Metabolism and Diabetes, University of Miami, Miami, FL
- VA Ann Arbor Healthcare System, Ann Arbor, MI
- Miami VA Healthcare System, Miami, FL
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33
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Targeting Cellular Calcium Homeostasis to Prevent Cytokine-Mediated Beta Cell Death. Sci Rep 2017; 7:5611. [PMID: 28717166 PMCID: PMC5514111 DOI: 10.1038/s41598-017-05935-4] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2017] [Accepted: 06/06/2017] [Indexed: 12/30/2022] Open
Abstract
Pro-inflammatory cytokines are important mediators of islet inflammation, leading to beta cell death in type 1 diabetes. Although alterations in both endoplasmic reticulum (ER) and cytosolic free calcium levels are known to play a role in cytokine-mediated beta cell death, there are currently no treatments targeting cellular calcium homeostasis to combat type 1 diabetes. Here we show that modulation of cellular calcium homeostasis can mitigate cytokine- and ER stress-mediated beta cell death. The calcium modulating compounds, dantrolene and sitagliptin, both prevent cytokine and ER stress-induced activation of the pro-apoptotic calcium-dependent enzyme, calpain, and partly suppress beta cell death in INS1E cells and human primary islets. These agents are also able to restore cytokine-mediated suppression of functional ER calcium release. In addition, sitagliptin preserves function of the ER calcium pump, sarco-endoplasmic reticulum Ca2+-ATPase (SERCA), and decreases levels of the pro-apoptotic protein thioredoxin-interacting protein (TXNIP). Supporting the role of TXNIP in cytokine-mediated cell death, knock down of TXNIP in INS1-E cells prevents cytokine-mediated beta cell death. Our findings demonstrate that modulation of dynamic cellular calcium homeostasis and TXNIP suppression present viable pharmacologic targets to prevent cytokine-mediated beta cell loss in diabetes.
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Sims EK, Lakhter AJ, Anderson-Baucum E, Kono T, Tong X, Evans-Molina C. MicroRNA 21 targets BCL2 mRNA to increase apoptosis in rat and human beta cells. Diabetologia 2017; 60:1057-1065. [PMID: 28280903 PMCID: PMC5425307 DOI: 10.1007/s00125-017-4237-z] [Citation(s) in RCA: 77] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/21/2016] [Accepted: 02/03/2017] [Indexed: 12/22/2022]
Abstract
AIMS/HYPOTHESIS The role of beta cell microRNA (miR)-21 in the pathophysiology of type 1 diabetes has been controversial. Here, we sought to define the context of beta cell miR-21 upregulation in type 1 diabetes and the phenotype of beta cell miR-21 overexpression through target identification. METHODS Islets were isolated from NOD mice and mice treated with multiple low doses of streptozotocin, as a mouse model of diabetes. INS-1 832/13 beta cells and human islets were treated with IL-1β, IFN-γ and TNF-α to mimic the milieu of early type 1 diabetes. Cells and islets were transfected with miR-21 mimics or inhibitors. Luciferase assays and polyribosomal profiling (PRP) were performed to define miR-21-target interactions. RESULTS Beta cell miR-21 was increased in in vivo models of type 1 diabetes and cytokine-treated cells/islets. miR-21 overexpression decreased cell count and viability, and increased cleaved caspase 3 levels, suggesting increased cell death. In silico prediction tools identified the antiapoptotic mRNA BCL2 as a conserved miR-21 target. Consistent with this, miR-21 overexpression decreased BCL2 transcript and B cell lymphoma 2 (BCL2) protein production, while miR-21 inhibition increased BCL2 protein levels and reduced cleaved caspase 3 levels after cytokine treatment. miR-21-mediated cell death was abrogated in 828/33 cells, which constitutively overexpress Bcl2. Luciferase assays suggested a direct interaction between miR-21 and the BCL2 3' untranslated region. With miR-21 overexpression, PRP revealed a shift of the Bcl2 message towards monosome-associated fractions, indicating inhibition of Bcl2 translation. Finally, overexpression in dispersed human islets confirmed a reduction in BCL2 transcripts and increased cleaved caspase 3 production. CONCLUSIONS/INTERPRETATION In contrast to the pro-survival role reported in other systems, our results demonstrate that miR-21 increases beta cell death via BCL2 transcript degradation and inhibition of BCL2 translation.
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Affiliation(s)
- Emily K Sims
- Center for Diabetes and Metabolic Diseases, Indiana University School of Medicine, 635 Barnhill Drive, MS2031, Indianapolis, IN, 46202, USA.
- Department of Pediatrics, Indiana University School of Medicine, Indianapolis, IN, USA.
- Herman B. Wells Center for Pediatric Research, Indiana University School of Medicine, Indianapolis, IN, USA.
| | - Alexander J Lakhter
- Center for Diabetes and Metabolic Diseases, Indiana University School of Medicine, 635 Barnhill Drive, MS2031, Indianapolis, IN, 46202, USA
- Department of Pediatrics, Indiana University School of Medicine, Indianapolis, IN, USA
- Herman B. Wells Center for Pediatric Research, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Emily Anderson-Baucum
- Center for Diabetes and Metabolic Diseases, Indiana University School of Medicine, 635 Barnhill Drive, MS2031, Indianapolis, IN, 46202, USA
- Department of Medicine, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Tatsuyoshi Kono
- Center for Diabetes and Metabolic Diseases, Indiana University School of Medicine, 635 Barnhill Drive, MS2031, Indianapolis, IN, 46202, USA
- Herman B. Wells Center for Pediatric Research, Indiana University School of Medicine, Indianapolis, IN, USA
- Department of Medicine, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Xin Tong
- Center for Diabetes and Metabolic Diseases, Indiana University School of Medicine, 635 Barnhill Drive, MS2031, Indianapolis, IN, 46202, USA
- Department of Medicine, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Carmella Evans-Molina
- Center for Diabetes and Metabolic Diseases, Indiana University School of Medicine, 635 Barnhill Drive, MS2031, Indianapolis, IN, 46202, USA
- Herman B. Wells Center for Pediatric Research, Indiana University School of Medicine, Indianapolis, IN, USA
- Department of Medicine, Indiana University School of Medicine, Indianapolis, IN, USA
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, IN, USA
- Richard L. Roudebush VA Medical Center, Indianapolis, IN, USA
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35
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Tong X, Kono T, Anderson-Baucum EK, Yamamoto W, Gilon P, Lebeche D, Day RN, Shull GE, Evans-Molina C. SERCA2 Deficiency Impairs Pancreatic β-Cell Function in Response to Diet-Induced Obesity. Diabetes 2016; 65:3039-52. [PMID: 27489309 PMCID: PMC5033263 DOI: 10.2337/db16-0084] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/17/2016] [Accepted: 07/28/2016] [Indexed: 12/18/2022]
Abstract
The sarcoendoplasmic reticulum (ER) Ca(2+) ATPase 2 (SERCA2) pump is a P-type ATPase tasked with the maintenance of ER Ca(2+) stores. Whereas β-cell SERCA2 expression is reduced in diabetes, the role of SERCA2 in the regulation of whole-body glucose homeostasis has remained uncharacterized. To this end, SERCA2 heterozygous mice (S2HET) were challenged with a high-fat diet (HFD) containing 45% of kilocalories from fat. After 16 weeks of the HFD, S2HET mice were hyperglycemic and glucose intolerant, but adiposity and insulin sensitivity were not different between HFD-fed S2HET mice and HFD-fed wild-type controls. Consistent with a defect in β-cell function, insulin secretion, glucose-induced cytosolic Ca(2+) mobilization, and the onset of steady-state glucose-induced Ca(2+) oscillations were impaired in HFD-fed S2HET islets. Moreover, HFD-fed S2HET mice exhibited reduced β-cell mass and proliferation, altered insulin production and proinsulin processing, and increased islet ER stress and death. In contrast, SERCA2 activation with a small molecule allosteric activator increased ER Ca(2+) storage and rescued tunicamycin-induced β-cell death. In aggregate, these data suggest a critical role for SERCA2 and the regulation of ER Ca(2+) homeostasis in the β-cell compensatory response to diet-induced obesity.
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Affiliation(s)
- Xin Tong
- Department of Cellular and Integrative Physiology, Indiana University School of Medicine, Indianapolis, IN
| | - Tatsuyoshi Kono
- Department of Medicine, Indiana University School of Medicine, Indianapolis, IN
| | | | - Wataru Yamamoto
- Department of Cellular and Integrative Physiology, Indiana University School of Medicine, Indianapolis, IN
| | - Patrick Gilon
- Pôle d'endocrinologie, diabète et nutrition, Institut de recherche expérimentale et clinique, Université catholique de Louvain, Brussels, Belgium
| | - Djamel Lebeche
- Cardiovascular Research Institute and Diabetes Obesity and Metabolism Institute, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, NY
| | - Richard N Day
- Department of Cellular and Integrative Physiology, Indiana University School of Medicine, Indianapolis, IN
| | - Gary E Shull
- Department of Molecular Genetics, Biochemistry, and Microbiology, University of Cincinnati College of Medicine, Cincinnati, OH
| | - Carmella Evans-Molina
- Department of Cellular and Integrative Physiology, Indiana University School of Medicine, Indianapolis, IN Department of Medicine, Indiana University School of Medicine, Indianapolis, IN Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, IN Herman B Wells Center for Pediatric Research, Indiana University School of Medicine, Indianapolis, IN Roudebush VA Medical Center, Indianapolis, IN
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36
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Takatani T, Shirakawa J, Roe MW, Leech CA, Maier BF, Mirmira RG, Kulkarni RN. IRS1 deficiency protects β-cells against ER stress-induced apoptosis by modulating sXBP-1 stability and protein translation. Sci Rep 2016; 6:28177. [PMID: 27378176 PMCID: PMC4932502 DOI: 10.1038/srep28177] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2016] [Accepted: 05/31/2016] [Indexed: 01/05/2023] Open
Abstract
Endoplasmic reticulum (ER) stress is among several pathological features that underlie β-cell failure in the development of type 1 and type 2 diabetes. Adaptor proteins in the insulin/insulin-like-growth factor-1 signaling pathways, such as insulin receptor substrate-1 (IRS1) and IRS2, differentially impact β-cell survival but the underlying mechanisms remain unclear. Here we report that β-cells deficient in IRS1 (IRS1KO) are resistant, while IRS2 deficiency (IRS2KO) makes them susceptible to ER stress-mediated apoptosis. IRS1KOs exhibited low nuclear accumulation of spliced XBP-1 due to its poor stability, in contrast to elevated accumulation in IRS2KO. The reduced nuclear accumulation in IRS1KO was due to protein instability of Xbp1 secondary to proteasomal degradation. IRS1KO also demonstrated an attenuation in their general translation status in response to ER stress revealed by polyribosomal profiling. Phosphorylation of eEF2 was dramatically increased in IRS1KO enabling the β-cells to adapt to ER stress by blocking translation. Furthermore, significantly high ER calcium (Ca2+) was detected in IRS1KO β-cells even upon induction of ER stress. These observations suggest that IRS1 could be a therapeutic target for β-cell protection against ER stress-mediated cell death by modulating XBP-1 stability, protein synthesis, and Ca2+ storage in the ER.
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Affiliation(s)
- Tomozumi Takatani
- Islet Cell and Regenerative Biology, Joslin Diabetes Center, Department of Medicine, Brigham and Women's Hospital, Harvard Stem Cell Institute, Harvard Medical School, Boston, MA, USA
| | - Jun Shirakawa
- Islet Cell and Regenerative Biology, Joslin Diabetes Center, Department of Medicine, Brigham and Women's Hospital, Harvard Stem Cell Institute, Harvard Medical School, Boston, MA, USA
| | - Michael W Roe
- Department of Medicine, State University of New York (SUNY), Upstate Medical University, Syracuse, NY, USA
| | - Colin A Leech
- Department of Medicine, State University of New York (SUNY), Upstate Medical University, Syracuse, NY, USA
| | - Bernhard F Maier
- Department of Pediatrics and Herman B Wells Center for Pediatric Research, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Raghavendra G Mirmira
- Department of Pediatrics and Herman B Wells Center for Pediatric Research, Indiana University School of Medicine, Indianapolis, IN, USA.,Department of Cellular and Integrative Physiology, Department of Biochemistry and Molecular Biology, Department of Medicine, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Rohit N Kulkarni
- Islet Cell and Regenerative Biology, Joslin Diabetes Center, Department of Medicine, Brigham and Women's Hospital, Harvard Stem Cell Institute, Harvard Medical School, Boston, MA, USA
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Proinsulin and heat shock protein 90 as biomarkers of beta-cell stress in the early period after onset of type 1 diabetes. Transl Res 2016; 168:96-106.e1. [PMID: 26397425 PMCID: PMC4839287 DOI: 10.1016/j.trsl.2015.08.010] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/29/2015] [Revised: 08/12/2015] [Accepted: 08/28/2015] [Indexed: 11/23/2022]
Abstract
Rapid evaluation of therapies designed to preserve β cells in persons with type 1 diabetes (T1D) is hampered by limited availability of sensitive β-cell health biomarkers. In particular, biomarkers elucidating the presence and degree of β-cell stress are needed. We characterized β-cell secretory activity and stress in 29 new-onset T1D subjects (10.6 ± 3.0 years, 55% male) at diagnosis and then 8.2 ± 1.2 weeks later at first clinic follow-up. We did comparisons with 16 matched healthy controls. We evaluated hemoglobin A1c (HbA1c), β-cell function (random C-peptide [C] and proinsulin [PI]), β-cell stress (PI:C ratio), and the β-cell stress marker heat shock protein (HSP)90 and examined these parameters' relationships with clinical and laboratory characteristics at diagnosis. Mean diagnosis HbA1c was 11.3% (100 mmol/mol) and 7.6% (60 mmol/mol) at follow-up. C-peptide was low at diagnosis (P < 0.001 vs controls) and increased at follow-up (P < 0.001) to comparable with controls. PI did not differ from controls at diagnosis but increased at follow-up (P = 0.003) signifying increased release of PI alongside improved insulin secretion. PI:C ratios and HSP90 concentrations were elevated at both time points. Younger subjects had lower C-peptide and greater PI, PI:C, and HSP90. We also examined islets isolated from prediabetic nonobese diabetic mice and found that HSP90 levels were increased ∼4-fold compared with those in islets isolated from matched CD1 controls, further substantiating HSP90 as a marker of β-cell stress in T1D. Our data indicate that β-cell stress can be assessed using PI:C and HSP90. This stress persists after T1D diagnosis. Therapeutic approaches to reduce β-cell stress in new-onset T1D should be considered.
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Xiong X, Wang G, Tao R, Wu P, Kono T, Li K, Ding WX, Tong X, Tersey SA, Harris RA, Mirmira RG, Evans-Molina C, Dong XC. Sirtuin 6 regulates glucose-stimulated insulin secretion in mouse pancreatic beta cells. Diabetologia 2016; 59:151-160. [PMID: 26471901 PMCID: PMC4792692 DOI: 10.1007/s00125-015-3778-2] [Citation(s) in RCA: 58] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/23/2015] [Accepted: 09/22/2015] [Indexed: 12/31/2022]
Abstract
AIMS/HYPOTHESIS Sirtuin 6 (SIRT6) has been implicated in ageing, DNA repair and metabolism; however, its function in pancreatic beta cells is unclear. The aim of this study is to elucidate the role of SIRT6 in pancreatic beta cells. METHODS To investigate the function of SIRT6 in pancreatic beta cells, we performed Sirt6 gene knockdown in MIN6 cells and generated pancreatic- and beta cell-specific Sirt6 knockout mice. Islet morphology and glucose-stimulated insulin secretion (GSIS) were analysed. Glycolysis and oxygen consumption rates in SIRT6-deficient beta cells were measured. Cytosolic calcium was monitored using the Fura-2-AM fluorescent probe (Invitrogen, Grand Island, NY, USA). Mitochondria were analysed by immunoblots and electron microscopy. RESULTS Sirt6 knockdown in MIN6 beta cells led to a significant decrease in GSIS. Pancreatic beta cell Sirt6 knockout mice showed a ~50% decrease in GSIS. The knockout mouse islets had lower ATP levels compared with the wild-type controls. Mitochondrial oxygen consumption rates were significantly decreased in the SIRT6-deficient beta cells. Cytosolic calcium dynamics in response to glucose or potassium chloride were attenuated in the Sirt6 knockout islets. Numbers of damaged mitochondria were increased and mitochondrial complex levels were decreased in the SIRT6-deficient islets. CONCLUSIONS/INTERPRETATION These data suggest that SIRT6 is important for GSIS from pancreatic beta cells and activation of SIRT6 may be useful to improve insulin secretion in diabetes.
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Affiliation(s)
- Xiwen Xiong
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, 635 Barnhill Drive, MS1021D, Indianapolis, IN, 46202, USA
| | - Gaihong Wang
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, 635 Barnhill Drive, MS1021D, Indianapolis, IN, 46202, USA
| | - Rongya Tao
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, 635 Barnhill Drive, MS1021D, Indianapolis, IN, 46202, USA
| | - Pengfei Wu
- Richard Roudebush Veterans Affairs Medical Center, Indianapolis, IN, USA
| | - Tatsuyoshi Kono
- Department of Medicine, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Kevin Li
- Department of Pharmacology, Toxicology and Therapeutics, University of Kansas Medical Center, Kansas City, KS, USA
| | - Wen-Xing Ding
- Department of Pharmacology, Toxicology and Therapeutics, University of Kansas Medical Center, Kansas City, KS, USA
| | - Xin Tong
- Department of Medicine, Indiana University School of Medicine, Indianapolis, IN, USA
- Department of Cellular and Integrative Physiology, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Sarah A Tersey
- Department of Pediatrics, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Robert A Harris
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, 635 Barnhill Drive, MS1021D, Indianapolis, IN, 46202, USA
- Richard Roudebush Veterans Affairs Medical Center, Indianapolis, IN, USA
| | - Raghavendra G Mirmira
- Department of Pediatrics, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Carmella Evans-Molina
- Richard Roudebush Veterans Affairs Medical Center, Indianapolis, IN, USA
- Department of Medicine, Indiana University School of Medicine, Indianapolis, IN, USA
- Department of Cellular and Integrative Physiology, Indiana University School of Medicine, Indianapolis, IN, USA
| | - X Charlie Dong
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, 635 Barnhill Drive, MS1021D, Indianapolis, IN, 46202, USA.
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Lv L, Chen H, Sun J, Lu D, Chen C, Liu D. PRMT1 promotes glucose toxicity-induced β cell dysfunction by regulating the nucleo-cytoplasmic trafficking of PDX-1 in a FOXO1-dependent manner in INS-1 cells. Endocrine 2015; 49:669-82. [PMID: 25874535 DOI: 10.1007/s12020-015-0543-8] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/17/2014] [Accepted: 01/27/2015] [Indexed: 11/26/2022]
Abstract
Protein N-arginine methyltransferase-1 (PRMT1), the major asymmetric arginine methyltransferase, plays important roles in various cellular processes. Previous reports have demonstrated that levels and activities of PRMT1 can vary in animals with type 2 diabetes mellitus. The aim of this study was to assess the expression and mechanism of action of PRMT1 during glucose toxicity-induced β cell dysfunction. Liposome-mediated gene transfection was used to transfect INS-1 cells with siPRMT1, which inhibits PRMT1 expression, and pALTER-FOXO1, which overexpresses forkhead box protein O1 (FOXO1). The cells were then cultured in media containing 5.6 or 25 mmol/L glucose with or without the small molecule PRMT1 inhibitor AMI-1 for 48 h. The protein levels of PRMT1, the arginine methylated protein α-metR, FOXO1, Phospho-FOXO1, pancreas duodenum homeobox-1 (PDX-1), and the intracellular localization of PDX-1 and FOXO1 were then measured by western blotting. FOXO1 methylation was detected by immunoprecipitated with anti-PRMT1 antibody and were immunoblotted with α-metR. The levels of insulin mRNA were measured by real-time fluorescence quantitative PCR. Glucose-stimulated insulin secretion (GSIS) and intracellular insulin content were measured using radioimmunoassays. Intracellular Ca(2+) ([Ca(2+)]i) was detected using Fura-2 AM. Intracellular cAMP levels were measured using ELISA. Chronic exposure to high glucose impaired insulin secretion, decreased insulin mRNA levels and insulin content, increased intracellular [Ca(2+)]i and cAMP levels, and abolishes their responses to glucose. Inhibiting PRMT1 expression improved insulin secretion, increased mRNA levels and insulin content by regulating the intracellular translocation of PDX-1 and FOXO1, decreasing the methylation of FOXO1, and reducing intracellular [Ca(2+)]i and cAMP concentrations. Transient overexpression of constitutively active FOXO1 in nuclear reversed the AMI-1-induced improvement of β cell function without changing arginine methylation. It is concluded therefore that PRMT1 regulates GSIS in INS-1 cells, through enhanced methylation-induced nuclear localization of FOXO1, which subsequently suppresses the nuclear localization of PDX-1. Our results suggest a novel mechanism that might contribute to the deficient insulin secretion observed under conditions of chronically hyperglycemia.
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Affiliation(s)
- Lixia Lv
- Department of Endocrinology and Metabolism, The Second Affiliated Hospital of Chongqing Medical University, 76 Linjiang Road, Yuzhong District, Chongqing, 400010, China
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Tong X, Kono T, Evans-Molina C. Nitric oxide stress and activation of AMP-activated protein kinase impair β-cell sarcoendoplasmic reticulum calcium ATPase 2b activity and protein stability. Cell Death Dis 2015; 6:e1790. [PMID: 26086963 PMCID: PMC4669835 DOI: 10.1038/cddis.2015.154] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2015] [Revised: 04/13/2015] [Accepted: 04/20/2015] [Indexed: 11/15/2022]
Abstract
The sarcoendoplasmic reticulum Ca2+ ATPase 2b (SERCA2b) pump maintains a steep Ca2+ concentration gradient between the cytosol and ER lumen in the pancreatic β-cell, and the integrity of this gradient has a central role in regulated insulin production and secretion, maintenance of ER function and β-cell survival. We have previously demonstrated loss of β-cell SERCA2b expression under diabetic conditions. To define the mechanisms underlying this, INS-1 cells and rat islets were treated with the proinflammatory cytokine interleukin-1β (IL-1β) combined with or without cycloheximide or actinomycin D. IL-1β treatment led to increased inducible nitric oxide synthase (iNOS) gene and protein expression, which occurred concurrently with the activation of AMP-activated protein kinase (AMPK). IL-1β led to decreased SERCA2b mRNA and protein expression, whereas time-course experiments revealed a reduction in protein half-life with no change in mRNA stability. Moreover, SERCA2b protein but not mRNA levels were rescued by treatment with the NOS inhibitor l-NMMA (NG-monomethyl l-arginine), whereas the NO donor SNAP (S-nitroso-N-acetyl-d,l-penicillamine) and the AMPK activator AICAR (5-aminoimidazole-4-carboxamide ribonucleotide) recapitulated the effects of IL-1β on SERCA2b protein stability. Similarly, IL-1β-induced reductions in SERCA2b expression were rescued by pharmacological inhibition of AMPK with compound C or by transduction of a dominant-negative form of AMPK, whereas β-cell death was prevented in parallel. Finally, to determine a functional relationship between NO and AMPK signaling and SERCA2b activity, fura-2/AM (fura-2-acetoxymethylester) Ca2+ imaging experiments were performed in INS-1 cells. Consistent with observed changes in SERCA2b expression, IL-1β, SNAP and AICAR increased cytosolic Ca2+ and decreased ER Ca2+ levels, suggesting congruent modulation of SERCA activity under these conditions. In aggregate, these results show that SERCA2b protein stability is decreased under inflammatory conditions through NO- and AMPK-dependent pathways and provide novel insight into pathways leading to altered β-cell calcium homeostasis and reduced β-cell survival in diabetes.
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Affiliation(s)
- X Tong
- Department of Cellular and Integrative Physiology, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - T Kono
- Department of Medicine, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - C Evans-Molina
- 1] Department of Cellular and Integrative Physiology, Indiana University School of Medicine, Indianapolis, IN 46202, USA [2] Department of Medicine, Indiana University School of Medicine, Indianapolis, IN 46202, USA [3] Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, IN 46202, USA [4] The Herman B Wells Center for Pediatric Research, Indiana University School of Medicine, Indianapolis, IN 46202, USA [5] The Roudebush VA Medical Center, Indianapolis, IN 46202, USA
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