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Pervanidis KA, D'Angelo GD, Weisner J, Brandherm S, Rauh D. Akt Inhibitor Advancements: From Capivasertib Approval to Covalent-Allosteric Promises. J Med Chem 2024; 67:6052-6063. [PMID: 38592948 DOI: 10.1021/acs.jmedchem.4c00075] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/11/2024]
Abstract
Akt kinase is vital in cell growth, survival, metabolism, and migration. Dysregulation of Akt signaling is implicated in cancer and metabolic disorders. In the context of cancer, overactive Akt promotes cell survival and proliferation. This has spurred extensive research into developing Akt inhibitors as potential therapeutic agents to disrupt aberrant Akt signaling. Akt inhibitors are classified into three main types: ATP-competitive, allosteric, and covalent-allosteric inhibitors (CAAIs). ATP-competitive inhibitors compete with ATP for binding to Akt, allosteric inhibitors interact with the Pleckstrin homology (PH) domain, and covalent-allosteric inhibitors form covalent bonds, making them more potent and selective. Notably, capivasertib (AZD5363), a potent ATP-competitive Akt inhibitor, received FDA approval in November 2023 for use in combination with the estrogen receptor degrader fulvestrant to treat breast cancer. Challenges remain, including improving selectivity, identifying biomarkers to tailor treatments, and enhancing therapeutic efficacy while minimizing adverse effects. Particularly covalent-allosteric inhibitors hold promise for future more effective and personalized treatments.
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Affiliation(s)
- Kosmas Alexandros Pervanidis
- Department of Chemistry and Chemical Biology, TU Dortmund University and Drug Discovery Hub Dortmund (DDHD), Zentrum für Integrierte Wirkstoffforschung (ZIW), Otto-Hahn-Strasse 4a, 44227 Dortmund, Germany
| | - Giovanni Danilo D'Angelo
- Department of Chemistry and Chemical Biology, TU Dortmund University and Drug Discovery Hub Dortmund (DDHD), Zentrum für Integrierte Wirkstoffforschung (ZIW), Otto-Hahn-Strasse 4a, 44227 Dortmund, Germany
| | - Jörn Weisner
- Department of Chemistry and Chemical Biology, TU Dortmund University and Drug Discovery Hub Dortmund (DDHD), Zentrum für Integrierte Wirkstoffforschung (ZIW), Otto-Hahn-Strasse 4a, 44227 Dortmund, Germany
- KyDo Therapeutics, Otto-Hahn-Strasse 15, 44227 Dortmund, Germany
| | - Sven Brandherm
- Department of Chemistry and Chemical Biology, TU Dortmund University and Drug Discovery Hub Dortmund (DDHD), Zentrum für Integrierte Wirkstoffforschung (ZIW), Otto-Hahn-Strasse 4a, 44227 Dortmund, Germany
- KyDo Therapeutics, Otto-Hahn-Strasse 15, 44227 Dortmund, Germany
| | - Daniel Rauh
- Department of Chemistry and Chemical Biology, TU Dortmund University and Drug Discovery Hub Dortmund (DDHD), Zentrum für Integrierte Wirkstoffforschung (ZIW), Otto-Hahn-Strasse 4a, 44227 Dortmund, Germany
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Ivovic A, Yung JHM, Oprescu AI, Vlavcheski F, Mori Y, Rahman SMN, Ye W, Eversley JA, Wheeler MB, Woo M, Tsiani E, Giacca A. β-Cell Insulin Resistance Plays a Causal Role in Fat-Induced β-Cell Dysfunction In Vitro and In Vivo. Endocrinology 2024; 165:bqae044. [PMID: 38578954 PMCID: PMC11033845 DOI: 10.1210/endocr/bqae044] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/28/2023] [Revised: 03/27/2024] [Accepted: 04/04/2024] [Indexed: 04/07/2024]
Abstract
In the classical insulin target tissues of liver, muscle, and adipose tissue, chronically elevated levels of free fatty acids (FFA) impair insulin signaling. Insulin signaling molecules are also present in β-cells where they play a role in β-cell function. Therefore, inhibition of the insulin/insulin-like growth factor 1 pathway may be involved in fat-induced β-cell dysfunction. To address the role of β-cell insulin resistance in FFA-induced β-cell dysfunction we co-infused bisperoxovanadate (BPV) with oleate or olive oil for 48 hours in rats. BPV, a tyrosine phosphatase inhibitor, acts as an insulin mimetic and is devoid of any antioxidant effect that could prevent β-cell dysfunction, unlike most insulin sensitizers. Following fat infusion, rats either underwent hyperglycemic clamps for assessment of β-cell function in vivo or islets were isolated for ex vivo assessment of glucose-stimulated insulin secretion (GSIS). We also incubated islets with oleate or palmitate and BPV for in vitro assessment of GSIS and Akt (protein kinase B) phosphorylation. Next, mice with β-cell specific deletion of PTEN (phosphatase and tensin homolog; negative regulator of insulin signaling) and littermate controls were infused with oleate for 48 hours, followed by hyperglycemic clamps or ex vivo evaluation of GSIS. In rat experiments, BPV protected against fat-induced impairment of β-cell function in vivo, ex vivo, and in vitro. In mice, β-cell specific deletion of PTEN protected against oleate-induced β-cell dysfunction in vivo and ex vivo. These data support the hypothesis that β-cell insulin resistance plays a causal role in FFA-induced β-cell dysfunction.
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Affiliation(s)
- Aleksandar Ivovic
- Department of Physiology, Faculty of Medicine, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Justin Hou Ming Yung
- Department of Physiology, Faculty of Medicine, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Andrei I Oprescu
- Institute of Medical Science, Faculty of Medicine, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Filip Vlavcheski
- Department of Health Sciences, Brock University, St. Catharines, ON L2S 3A1, Canada
| | - Yusaku Mori
- Department of Physiology, Faculty of Medicine, University of Toronto, Toronto, ON M5S 1A8, Canada
- Division of Diabetes, Metabolism, and Endocrinology, Anti-Glycation Research Section, Department of Medicine, Showa University School of Medicine, Shinagawa, Tokyo 142-8555, Japan
| | - S M Niazur Rahman
- Department of Physiology, Faculty of Medicine, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Wenyue Ye
- Department of Physiology, Faculty of Medicine, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Judith A Eversley
- Department of Physiology, Faculty of Medicine, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Michael B Wheeler
- Department of Physiology, Faculty of Medicine, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Minna Woo
- Institute of Medical Science, Faculty of Medicine, University of Toronto, Toronto, ON M5S 1A8, Canada
- Toronto General Hospital Research Institute, University Health Network, University of Toronto, Toronto, ON M5G 2C4, Canada
- Division of Endocrinology, Department of Medicine, University Health Network, University of Toronto, Toronto, ON M5G 2C4, Canada
- Department of Medicine, Faculty of Medicine, University of Toronto, Toronto, ON M5S 1A8, Canada
- Banting and Best Diabetes Centre, University of Toronto, Toronto, ON M5G 2C4, Canada
| | - Evangelia Tsiani
- Department of Health Sciences, Brock University, St. Catharines, ON L2S 3A1, Canada
| | - Adria Giacca
- Department of Physiology, Faculty of Medicine, University of Toronto, Toronto, ON M5S 1A8, Canada
- Institute of Medical Science, Faculty of Medicine, University of Toronto, Toronto, ON M5S 1A8, Canada
- Department of Medicine, Faculty of Medicine, University of Toronto, Toronto, ON M5S 1A8, Canada
- Banting and Best Diabetes Centre, University of Toronto, Toronto, ON M5G 2C4, Canada
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Ren X, Dai Y, Shan M, Zheng J, Zhang Z, Shen T. Astragalus polysaccharide restores insulin secretion impaired by lipopolysaccharides through the protein kinase B /mammalian target of rapamycin/glucose transporter 2 pathway. BMC Complement Med Ther 2023; 23:358. [PMID: 37817130 PMCID: PMC10563267 DOI: 10.1186/s12906-023-04188-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2023] [Accepted: 09/29/2023] [Indexed: 10/12/2023] Open
Abstract
BACKGROUND Lipopolysaccharide (LPS)-induced dysfunction of pancreatic β-cells leads to impaired insulin (INS) secretion. Astragalus polysaccharide (APS) is a bioactive heteropolysaccharide extracted from Astragalus membranaceus and is a popular Chinese herbal medicine. This study aimed to elucidate the mechanisms by which APS affects INS secretion from β-cells under LPS stress. METHODS Rat insulinoma (INS-1) cells were treated with LPS at a low, medium, or high concentration of APS. Glucose-stimulated insulin secretion (GSIS) was evaluated using an enzyme-linked immunosorbent assay (ELISA). Transcriptome sequencing was used to assess genome-wide gene expression. Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis was used to determine the signaling pathways affected by APS. Quantitative reverse transcription-polymerase chain reaction (qRT-PCR) was performed to evaluate the gene expression of glucose transporter 2 (GLUT2), glucokinase (GCK), pancreatic duodenal homeobox-1 (PDX-1), and INS. Western blot analysis was used to detect the protein expression of phosphorylated protein kinase B (p-Akt), total Akt (t-Akt), phosphorylated mammalian target of rapamycin (p-mTOR), total mTOR (t-mTOR), and GLUT2. RESULTS LPS decreased GLUT2, GCK, PDX-1, and INS expression and reduced GSIS. These LPS-induced decreases in gene expression and GSIS were restored by APS treatment. In addition, transcriptome sequencing in combination with KEGG enrichment analysis revealed changes in the INS signaling pathway following APS treatment. LPS decreased p-Akt and p-mTOR expression, which was restored by APS treatment. The restorative effects of APS on GSIS as well as on the expression of GLUT2, GCK, PDX-1, and INS were abolished by treatment with the Akt inhibitor MK2206 or the mTOR inhibitor rapamycin (RPM). CONCLUSIONS APS restored GSIS in LPS-stimulated pancreatic β-cells by activating the Akt/mTOR/GLUT2 signaling pathway.
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Affiliation(s)
- Xiaodan Ren
- School of Basic Medicine, Chengdu University of Traditional Chinese Medicine, No. 37, Shi-er-qiao Road, Jinniu District, 610075, 610075, Chengdu, Chengdu, Sichuan, China
- Department of Integrative Medicine, Xinqiao Hospital, Army Medical University, Chongqing, China
| | - Ying Dai
- Department of Integrative Medicine, Xinqiao Hospital, Army Medical University, Chongqing, China
| | - Mengya Shan
- Department of Integrative Medicine, Xinqiao Hospital, Army Medical University, Chongqing, China
| | - Jing Zheng
- Department of Integrative Medicine, Xinqiao Hospital, Army Medical University, Chongqing, China
| | - Zhongyi Zhang
- School of Basic Medicine, Chengdu University of Traditional Chinese Medicine, No. 37, Shi-er-qiao Road, Jinniu District, 610075, 610075, Chengdu, Chengdu, Sichuan, China
| | - Tao Shen
- School of Basic Medicine, Chengdu University of Traditional Chinese Medicine, No. 37, Shi-er-qiao Road, Jinniu District, 610075, 610075, Chengdu, Chengdu, Sichuan, China.
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Lubaczeuski C, Bozadjieva-Kramer N, Louzada RA, Gittes GK, Leibowitz G, Bernal-Mizrachi E. Time-dependent effects of endogenous hyperglucagonemia on glucose homeostasis and hepatic glucagon action. JCI Insight 2023; 8:e162255. [PMID: 37140984 PMCID: PMC10393226 DOI: 10.1172/jci.insight.162255] [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: 06/02/2022] [Accepted: 05/03/2023] [Indexed: 05/05/2023] Open
Abstract
Elevation of glucagon levels and increase in α cell proliferation is associated with states of hyperglycemia in diabetes. A better understanding of the molecular mechanisms governing glucagon secretion could have major implications for understanding abnormal responses to hypoglycemia in patients with diabetes and provide novel avenues for diabetes management. Using mice with inducible induction of Rheb1 in α cells (αRhebTg mice), we showed that short-term activation of mTORC1 signaling is sufficient to induce hyperglucagonemia through increased glucagon secretion. Hyperglucagonemia in αRhebTg mice was also associated with an increase in α cell size and mass expansion. This model allowed us to identify the effects of chronic and short-term hyperglucagonemia on glucose homeostasis by regulating glucagon signaling in the liver. Short-term hyperglucagonemia impaired glucose tolerance, which was reversible over time. Liver glucagon resistance in αRhebTg mice was associated with reduced expression of the glucagon receptor and genes involved in gluconeogenesis, amino acid metabolism, and urea production. However, only genes regulating gluconeogenesis returned to baseline upon improvement of glycemia. Overall, these studies demonstrate that hyperglucagonemia exerts a biphasic response on glucose metabolism: Short-term hyperglucagonemia lead to glucose intolerance, whereas chronic exposure to glucagon reduced hepatic glucagon action and improved glucose tolerance.
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Affiliation(s)
- Camila Lubaczeuski
- Department of Medicine, Division Endocrinology, Metabolism and Diabetes, Miller School of Medicine, University of Miami, Miami, Florida, USA
| | - Nadejda Bozadjieva-Kramer
- Veterans Affairs Ann Arbor Healthcare System, Research Service, Ann Arbor, Michigan, USA
- Department of Surgery, University of Michigan, Ann Arbor, Michigan, USA
| | - Ruy A. Louzada
- Department of Medicine, Division Endocrinology, Metabolism and Diabetes, Miller School of Medicine, University of Miami, Miami, Florida, USA
| | - George K. Gittes
- Childrens Hospital, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Gil Leibowitz
- Diabetes Unit and Endocrine Service, Hadassah-Hebrew University Medical Center, Jerusalem, Israel
| | - Ernesto Bernal-Mizrachi
- Department of Medicine, Division Endocrinology, Metabolism and Diabetes, Miller School of Medicine, University of Miami, Miami, Florida, USA
- Diabetes Unit and Endocrine Service, Hadassah-Hebrew University Medical Center, Jerusalem, Israel
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Cao R, Tian H, Zhang Y, Liu G, Xu H, Rao G, Tian Y, Fu X. Signaling pathways and intervention for therapy of type 2 diabetes mellitus. MedComm (Beijing) 2023; 4:e283. [PMID: 37303813 PMCID: PMC10248034 DOI: 10.1002/mco2.283] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2023] [Revised: 04/18/2023] [Accepted: 04/27/2023] [Indexed: 06/13/2023] Open
Abstract
Type 2 diabetes mellitus (T2DM) represents one of the fastest growing epidemic metabolic disorders worldwide and is a strong contributor for a broad range of comorbidities, including vascular, visual, neurological, kidney, and liver diseases. Moreover, recent data suggest a mutual interplay between T2DM and Corona Virus Disease 2019 (COVID-19). T2DM is characterized by insulin resistance (IR) and pancreatic β cell dysfunction. Pioneering discoveries throughout the past few decades have established notable links between signaling pathways and T2DM pathogenesis and therapy. Importantly, a number of signaling pathways substantially control the advancement of core pathological changes in T2DM, including IR and β cell dysfunction, as well as additional pathogenic disturbances. Accordingly, an improved understanding of these signaling pathways sheds light on tractable targets and strategies for developing and repurposing critical therapies to treat T2DM and its complications. In this review, we provide a brief overview of the history of T2DM and signaling pathways, and offer a systematic update on the role and mechanism of key signaling pathways underlying the onset, development, and progression of T2DM. In this content, we also summarize current therapeutic drugs/agents associated with signaling pathways for the treatment of T2DM and its complications, and discuss some implications and directions to the future of this field.
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Affiliation(s)
- Rong Cao
- Department of Endocrinology and MetabolismState Key Laboratory of Biotherapy and Cancer CenterWest China HospitalSichuan University and Collaborative Innovation Center of BiotherapyChengduSichuanChina
| | - Huimin Tian
- Department of Endocrinology and MetabolismState Key Laboratory of Biotherapy and Cancer CenterWest China Medical School, West China HospitalSichuan UniversityChengduSichuanChina
| | - Yu Zhang
- Department of Endocrinology and MetabolismState Key Laboratory of Biotherapy and Cancer CenterWest China Medical School, West China HospitalSichuan UniversityChengduSichuanChina
| | - Geng Liu
- Department of Endocrinology and MetabolismState Key Laboratory of Biotherapy and Cancer CenterWest China HospitalSichuan University and Collaborative Innovation Center of BiotherapyChengduSichuanChina
| | - Haixia Xu
- Department of Endocrinology and MetabolismState Key Laboratory of Biotherapy and Cancer CenterWest China HospitalSichuan University and Collaborative Innovation Center of BiotherapyChengduSichuanChina
| | - Guocheng Rao
- Department of Endocrinology and MetabolismState Key Laboratory of Biotherapy and Cancer CenterWest China Medical School, West China HospitalSichuan UniversityChengduSichuanChina
| | - Yan Tian
- Department of Endocrinology and MetabolismState Key Laboratory of Biotherapy and Cancer CenterWest China HospitalSichuan University and Collaborative Innovation Center of BiotherapyChengduSichuanChina
| | - Xianghui Fu
- Department of Endocrinology and MetabolismState Key Laboratory of Biotherapy and Cancer CenterWest China HospitalSichuan University and Collaborative Innovation Center of BiotherapyChengduSichuanChina
- Department of Endocrinology and MetabolismState Key Laboratory of Biotherapy and Cancer CenterWest China Medical School, West China HospitalSichuan UniversityChengduSichuanChina
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Al-Romaiyan A, Masocha W, Oyedemi S, Marafie SK, Huang GC, Jones PM, Persaud SJ. Commiphora myrrha stimulates insulin secretion from β-cells through activation of atypical protein kinase C and mitogen-activated protein kinase. JOURNAL OF ETHNOPHARMACOLOGY 2023; 302:115937. [PMID: 36410575 DOI: 10.1016/j.jep.2022.115937] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/24/2022] [Revised: 08/22/2022] [Accepted: 11/11/2022] [Indexed: 06/16/2023]
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE Ayurvedic medicine has been used in the treatment of diabetes mellitus for centuries. In Arabia and some areas of Africa, Commiphora myrrha (CM) has been extensively used as a plant-based remedy. We have previously shown that an aqueous CM resin solution directly stimulates insulin secretion from MIN6 cells, a mouse β-cell line, and isolated mouse and human islets. However, the signaling pathways involved in CM-induced insulin secretion are completely unknown. Insulin secretion is normally triggered by elevations in intracellular Ca2+ ([Ca2+]i) through voltage gated Ca2+ channels (VGCC) and activation of protein kinases. Protein and lipid kinases such as protein kinase A (PKA), Ca2+-calmodulin dependent protein kinase II (CaMKII), phosphoinositide 3-kinases (PI3Ks), protein kinase C (PKC) and mitogen-activated protein kinase (MAPK), specifically extracellular signal-regulated kinases (ERK1/2), may be involved in receptor-operated insulin secretion. Therefore, we hypothesized that CM may induce insulin secretion by modulating the activity of VGCC and/or one or more of the above kinases. AIM OF THE STUDY To investigate the possible molecular mechanism of action of CM-induced insulin secretion. The effects of aqueous CM resin extract on [Ca2+]i and protein kinase activation from β-cells were examined. METHODS The effect of aqueous CM resin solution on [Ca2+]i was assessed using Ca2+ microfluorimetry. The involvement of VGCC in CM-induced insulin secretion was investigated using static and perifusion insulin secretion experiments in the presence of either EGTA, a Ca2+ chelator, or nifedipine, a blocker of VGCC. The involvement of kinase activation in the stimulatory effect of CM on insulin secretion was examined by using static and perifusion insulin secretion experiments in the presence of known pharmacological inhibitors and/or downregulation of specific kinases. The effects of CM on phosphorylation of PKCζ and ERK1/2 were also assessed using the Wes™ capillary-based protein electrophoresis. RESULTS Ca2+ microfluorimetry measurements showed that exposing MIN6 cells to CM (0.5-2 mg/mL) was not associated with changes in [Ca2+]i. Similarly, incubating MIN6 cells and mouse islets with EGTA and nifedipine, respectively, did not attenuate the insulin secretion induced by CM. However, incubating mouse and human islets with CM in the presence of staurosporine, a non-selective protein kinase inhibitor, completely blocked the effect of CM on insulin secretion. Exposing mouse islets to CM in the presence of H89, KN62 and LY294002, inhibitors of PKA, CaMKII and PI3K, respectively, did not reduce CM-induced insulin secretion. However, incubating mouse and human islets with CM in the presence of Ro 31-8220, a pan-PKC inhibitor, diminished insulin secretion stimulated by CM, whereas inhibiting the action of typical PKC (with Go6976) and PLCβ (with U73122) did not affect CM-stimulated insulin secretion. Similarly, downregulating typical and novel PKC by chronic exposure of mouse islets to phorbol 12-myristate 13-acetate (PMA) was also not associated with a decrease in the stimulatory effect of CM on insulin secretion. Interestingly, CM-induced insulin secretion from mouse islets was inhibited in the presence of the PKCζ inhibitor ZIP and a MAPK inhibitor PD 98059. In addition, Wes™ capillary-based protein electrophoresis indicated that expression of the phosphorylated forms of PKCζ and ERK1/2, a MAPK, was significantly increased following exposure of INS-1832/13 cells, a rat insulinoma cell line, to CM. CONCLUSIONS Our data indicate that CM directly stimulates insulin secretion through activating known downstream effectors of insulin-stimulus secretion coupling. Indeed, the increase in insulin secretion seen with CM is independent of changes in [Ca2+]i and does not involve activation of VGCC. Instead, the CM stimulatory effect on insulin secretion is completely dependent on protein kinase activation. Our findings indicate that CM could induce insulin exocytosis by stimulating the phosphorylation and activation of PKCζ, which in turn phosphorylates and activates ERK1/2.
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Affiliation(s)
- Altaf Al-Romaiyan
- Department of Pharmacology & Therapeutics, Faculty of Pharmacy, Kuwait University, Kuwait.
| | - Willias Masocha
- Department of Pharmacology & Therapeutics, Faculty of Pharmacy, Kuwait University, Kuwait.
| | - Sunday Oyedemi
- School of Science and Technology, Nottingham Trent University, Clifton Lane, Nottingham, NG11 8NS, UK.
| | - Sulaiman K Marafie
- Biochemistry and Molecular Biology Department, Dasman Diabetes Institute, Kuwait.
| | - Guo-Cai Huang
- Department of Diabetes, School of Cardiovascular Medicine &Sciences, Faculty of Life Sciences and Medicine, King's College London, UK.
| | - Peter M Jones
- Department of Diabetes, School of Cardiovascular Medicine &Sciences, Faculty of Life Sciences and Medicine, King's College London, UK.
| | - Shanta J Persaud
- Department of Diabetes, School of Cardiovascular Medicine &Sciences, Faculty of Life Sciences and Medicine, King's College London, UK.
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Goode RA, Hum JM, Kalwat MA. Therapeutic Strategies Targeting Pancreatic Islet β-Cell Proliferation, Regeneration, and Replacement. Endocrinology 2022; 164:6836713. [PMID: 36412119 PMCID: PMC9923807 DOI: 10.1210/endocr/bqac193] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/09/2022] [Revised: 11/16/2022] [Accepted: 11/18/2022] [Indexed: 11/23/2022]
Abstract
Diabetes results from insufficient insulin production by pancreatic islet β-cells or a loss of β-cells themselves. Restoration of regulated insulin production is a predominant goal of translational diabetes research. Here, we provide a brief overview of recent advances in the fields of β-cell proliferation, regeneration, and replacement. The discovery of therapeutic targets and associated small molecules has been enabled by improved understanding of β-cell development and cell cycle regulation, as well as advanced high-throughput screening methodologies. Important findings in β-cell transdifferentiation, neogenesis, and stem cell differentiation have nucleated multiple promising therapeutic strategies. In particular, clinical trials are underway using in vitro-generated β-like cells from human pluripotent stem cells. Significant challenges remain for each of these strategies, but continued support for efforts in these research areas will be critical for the generation of distinct diabetes therapies.
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Affiliation(s)
- Roy A Goode
- Division of Biomedical Sciences, College of Osteopathic Medicine, Marian University, Indianapolis, IN, USA
| | - Julia M Hum
- Division of Biomedical Sciences, College of Osteopathic Medicine, Marian University, Indianapolis, IN, USA
| | - Michael A Kalwat
- Correspondence: Michael A. Kalwat, PhD, Lilly Diabetes Center of Excellence, Indiana Biosciences Research Institute, 1210 Waterway Blvd, Suite 2000, Indianapolis, IN 46202, USA. or
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Jain C, Bilekova S, Lickert H. Targeting pancreatic β cells for diabetes treatment. Nat Metab 2022; 4:1097-1108. [PMID: 36131204 DOI: 10.1038/s42255-022-00618-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Accepted: 07/13/2022] [Indexed: 11/09/2022]
Abstract
Insulin is a life-saving drug for patients with type 1 diabetes; however, even today, no pharmacotherapy can prevent the loss or dysfunction of pancreatic insulin-producing β cells to stop or reverse disease progression. Thus, pancreatic β cells have been a main focus for cell-replacement and regenerative therapies as a curative treatment for diabetes. In this Review, we highlight recent advances toward the development of diabetes therapies that target β cells to enhance proliferation, redifferentiation and protection from cell death and/or enable selective killing of senescent β cells. We describe currently available therapies and their mode of action, as well as insufficiencies of glucagon-like peptide 1 (GLP-1) and insulin therapies. We discuss and summarize data collected over the last decades that support the notion that pharmacological targeting of β cell insulin signalling might protect and/or regenerate β cells as an improved treatment of patients with diabetes.
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Affiliation(s)
- Chirag Jain
- Institute of Diabetes and Regeneration Research, Helmholtz Zentrum München, Neuherberg, Germany
- German Center for Diabetes Research (DZD), Neuherberg, Germany
- Immunology Discovery, Genentech Inc., South San Francisco, CA, USA
| | - Sara Bilekova
- Institute of Diabetes and Regeneration Research, Helmholtz Zentrum München, Neuherberg, Germany
- German Center for Diabetes Research (DZD), Neuherberg, Germany
| | - Heiko Lickert
- Institute of Diabetes and Regeneration Research, Helmholtz Zentrum München, Neuherberg, Germany.
- German Center for Diabetes Research (DZD), Neuherberg, Germany.
- Chair of β-Cell Biology, Technische Universität München, School of Medicine, Klinikum Rechts der Isar, München, Germany.
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Mahmoudi A, Atkin SL, Nikiforov NG, Sahebkar A. Therapeutic Role of Curcumin in Diabetes: An Analysis Based on Bioinformatic Findings. Nutrients 2022; 14:nu14153244. [PMID: 35956419 PMCID: PMC9370108 DOI: 10.3390/nu14153244] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2022] [Revised: 07/19/2022] [Accepted: 07/26/2022] [Indexed: 12/25/2022] Open
Abstract
BACKGROUND Diabetes is an increasingly prevalent global disease caused by the impairment in insulin production or insulin function. Diabetes in the long term causes both microvascular and macrovascular complications that may result in retinopathy, nephropathy, neuropathy, peripheral arterial disease, atherosclerotic cardiovascular disease, and cerebrovascular disease. Considerable effort has been expended looking at the numerous genes and pathways to explain the mechanisms leading to diabetes-related complications. Curcumin is a traditional medicine with several properties such as being antioxidant, anti-inflammatory, anti-cancer, and anti-microbial, which may have utility for treating diabetes complications. This study, based on the system biology approach, aimed to investigate the effect of curcumin on critical genes and pathways related to diabetes. METHODS We first searched interactions of curcumin in three different databases, including STITCH, TTD, and DGIdb. Subsequently, we investigated the critical curated protein targets for diabetes on the OMIM and DisGeNET databases. To find important clustering groups (MCODE) and critical hub genes in the network of diseases, we created a PPI network for all proteins obtained for diabetes with the aid of a string database and Cytoscape software. Next, we investigated the possible interactions of curcumin on diabetes-related genes using Venn diagrams. Furthermore, the impact of curcumin on the top scores of modular clusters was analysed. Finally, we conducted biological process and pathway enrichment analysis using Gene Ontology (GO) and KEGG based on the enrichR web server. RESULTS We acquired 417 genes associated with diabetes, and their constructed PPI network contained 298 nodes and 1651 edges. Next, the analysis of centralities in the PPI network indicated 15 genes with the highest centralities. Additionally, MCODE analysis identified three modular clusters, which highest score cluster (MCODE 1) comprises 19 nodes and 92 edges with 10.22 scores. Screening curcumin interactions in the databases identified 158 protein targets. A Venn diagram of genes related to diabetes and the protein targets of curcumin showed 35 shared proteins, which observed that curcumin could strongly interact with ten of the hub genes. Moreover, we demonstrated that curcumin has the highest interaction with MCODE1 among all MCODs. Several significant biological pathways in KEGG enrichment associated with 35 shared included the AGE-RAGE signaling pathway in diabetic complications, HIF-1 signaling pathway, PI3K-Akt signaling pathway, TNF signaling, and JAK-STAT signaling pathway. The biological processes of GO analysis were involved with the cellular response to cytokine stimulus, the cytokine-mediated signaling pathway, positive regulation of intracellular signal transduction and cytokine production in the inflammatory response. CONCLUSION Curcumin targeted several important genes involved in diabetes, supporting the previous research suggesting that it may have utility as a therapeutic agent in diabetes.
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Affiliation(s)
- Ali Mahmoudi
- Department of Medical Biotechnology and Nanotechnology, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Stephen L. Atkin
- School of Postgraduate Studies and Research, RCSI Medical University of Bahrain, Busaiteen 15503, Bahrain
- Correspondence: (S.L.A.); or (A.S.)
| | - Nikita G. Nikiforov
- Laboratory of Angiopathology, Institute of General Pathology and Pathophysiology, 125315 Moscow, Russia
| | - Amirhossein Sahebkar
- Applied Biomedical Research Center, Mashhad University of Medical Sciences, Mashhad, Iran
- Biotechnology Research Center, Pharmaceutical Technology Institute, Mashhad University of Medical Sciences, Mashhad, Iran
- Department of Biotechnology, School of Pharmacy, Mashhad University of Medical Sciences, Mashhad, Iran
- Correspondence: (S.L.A.); or (A.S.)
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10
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Blandino-Rosano M, Scheys JO, Werneck-de-Castro JP, Louzada RA, Almaça J, Leibowitz G, Rüegg MA, Hall MN, Bernal-Mizrachi E. Novel roles of mTORC2 in regulation of insulin secretion by actin filament remodeling. Am J Physiol Endocrinol Metab 2022; 323:E133-E144. [PMID: 35723227 PMCID: PMC9291412 DOI: 10.1152/ajpendo.00076.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Mammalian target of rapamycin (mTOR) kinase is an essential hub where nutrients and growth factors converge to control cellular metabolism. mTOR interacts with different accessory proteins to form complexes 1 and 2 (mTORC), and each complex has different intracellular targets. Although mTORC1's role in β-cells has been extensively studied, less is known about mTORC2's function in β-cells. Here, we show that mice with constitutive and inducible β-cell-specific deletion of RICTOR (βRicKO and iβRicKO mice, respectively) are glucose intolerant due to impaired insulin secretion when glucose is injected intraperitoneally. Decreased insulin secretion in βRicKO islets was caused by abnormal actin polymerization. Interestingly, when glucose was administered orally, no difference in glucose homeostasis and insulin secretion were observed, suggesting that incretins are counteracting the mTORC2 deficiency. Mechanistically, glucagon-like peptide-1 (GLP-1), but not gastric inhibitory polypeptide (GIP), rescued insulin secretion in vivo and in vitro by improving actin polymerization in βRicKO islets. In conclusion, mTORC2 regulates glucose-stimulated insulin secretion by promoting actin filament remodeling.NEW & NOTEWORTHY The current studies uncover a novel mechanism linking mTORC2 signaling to glucose-stimulated insulin secretion by modulation of the actin filaments. This work also underscores the important role of GLP-1 in rescuing defects in insulin secretion by modulating actin polymerization and suggests that this effect is independent of mTORC2 signaling.
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Affiliation(s)
- Manuel Blandino-Rosano
- Division of Endocrinology, Diabetes, and Metabolism, Department of Medicine, University of Miami Miller School of Medicine, Miami, Florida
| | - Joshua O Scheys
- Medical School, Division of Metabolism, Endocrinology, and Diabetes and Brehm Center for Diabetes Research, Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan
| | - Joao Pedro Werneck-de-Castro
- Division of Endocrinology, Diabetes, and Metabolism, Department of Medicine, University of Miami Miller School of Medicine, Miami, Florida
| | - Ruy A Louzada
- Division of Endocrinology, Diabetes, and Metabolism, Department of Medicine, University of Miami Miller School of Medicine, Miami, Florida
| | - Joana Almaça
- Division of Endocrinology, Diabetes, and Metabolism, Department of Medicine, University of Miami Miller School of Medicine, Miami, Florida
| | - Gil Leibowitz
- Diabetes Unit and Endocrine Service, Hadassah-Hebrew University Medical Center, Jerusalem, Israel
| | | | | | - Ernesto Bernal-Mizrachi
- Division of Endocrinology, Diabetes, and Metabolism, Department of Medicine, University of Miami Miller School of Medicine, Miami, Florida
- Miami VA Healthcare System, Miami, Florida
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11
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Mugabo Y, Zhao C, Tan JJ, Ghosh A, Campbell SA, Fadzeyeva E, Paré F, Pan SS, Galipeau M, Ast J, Broichhagen J, Hodson DJ, Mulvihill EE, Petropoulos S, Lim GE. 14-3-3ζ constrains insulin secretion by regulating mitochondrial function in pancreatic β-cells. JCI Insight 2022; 7:156378. [PMID: 35298439 PMCID: PMC9089799 DOI: 10.1172/jci.insight.156378] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2021] [Accepted: 03/11/2022] [Indexed: 11/17/2022] Open
Abstract
While critical for neurotransmitter synthesis, 14-3-3 proteins are often assumed to have redundant functions due to their ubiquitous expression, but despite this assumption, various 14-3-3 isoforms have been implicated in regulating metabolism. We previously reported contributions of 14-3-3ζ in β cell function, but these studies were performed in tumor-derived MIN6 cells and systemic KO mice. To further characterize the regulatory roles of 14-3-3ζ in β cell function, we generated β cell–specific 14-3-3ζ–KO mice. Although no effects on β cell mass were detected, potentiated glucose-stimulated insulin secretion (GSIS), mitochondrial function, and ATP synthesis were observed. Deletion of 14-3-3ζ also altered the β cell transcriptome, as genes associated with mitochondrial respiration and oxidative phosphorylation were upregulated. Acute 14-3-3 protein inhibition in mouse and human islets recapitulated the enhancements in GSIS and mitochondrial function, suggesting that 14-3-3ζ is the critical isoform in β cells. In dysfunctional db/db islets and human islets from type 2 diabetic donors, expression of Ywhaz/YWHAZ, the gene encoding 14-3-3ζ, was inversely associated with insulin secretion, and pan–14-3-3 protein inhibition led to enhanced GSIS and mitochondrial function. Taken together, this study demonstrates important regulatory functions of 14-3-3ζ in the regulation of β cell function and provides a deeper understanding of how insulin secretion is controlled in β cells.
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Affiliation(s)
- Yves Mugabo
- Department of Medicine, Université de Montréal, Montreal, Canada
| | - Cheng Zhao
- Division of Obstetrics and Gynecology, Department of Clinical Science, Karolinska Institutet and Karolinska University Hospital, Stockholm, Sweden
| | - Ju Jing Tan
- Immunopathology Axis, Centre de Recherche du Centre hospitalier de l'Université de Montréal, Montreal, Canada
| | - Anindya Ghosh
- Department of Medicine, Université de Montréal, Montreal, Canada
| | - Scott A Campbell
- Cardiometabolic Axis, Centre de Recherche du Centre hospitalier de l'Université de Montréal, Montreal, Canada
| | - Evgenia Fadzeyeva
- Energy Substrate Laboratory, University of Ottawa Heart Institute, Ottawa, Canada
| | - Frédéric Paré
- Cardiometabolic Axis, Centre de recherche du CHUM (CRCHUM), Montreal, Canada
| | - Siew Siew Pan
- Department of Medicine, Université de Montréal, Montreal, Canada
| | - Maria Galipeau
- Department of Medicine, Université de Montréal, Montreal, Canada
| | - Julia Ast
- Institute of Metabolism and Systems Research (IMSR), Centre of Membrane Pro, University of Birmingham, Birmingham, United Kingdom
| | - Johannes Broichhagen
- Department of Chemical Biology, Leibniz-Forschungsinstitut für Molekulare Pharmakologie, Berlin, Germany
| | - David J Hodson
- Institute of Metabolism and Systems Research (IMSR), Centre of Membrane Pro, University of Birmingham, Birmingham, United Kingdom
| | - Erin E Mulvihill
- Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, Canada
| | | | - Gareth E Lim
- Department of Medicine, Université de Montréal, Montreal, Canada
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12
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Skovsø S, Panzhinskiy E, Kolic J, Cen HH, Dionne DA, Dai XQ, Sharma RB, Elghazi L, Ellis CE, Faulkner K, Marcil SAM, Overby P, Noursadeghi N, Hutchinson D, Hu X, Li H, Modi H, Wildi JS, Botezelli JD, Noh HL, Suk S, Gablaski B, Bautista A, Kim R, Cras-Méneur C, Flibotte S, Sinha S, Luciani DS, Nislow C, Rideout EJ, Cytrynbaum EN, Kim JK, Bernal-Mizrachi E, Alonso LC, MacDonald PE, Johnson JD. Beta-cell specific Insr deletion promotes insulin hypersecretion and improves glucose tolerance prior to global insulin resistance. Nat Commun 2022; 13:735. [PMID: 35136059 PMCID: PMC8826929 DOI: 10.1038/s41467-022-28039-8] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2021] [Accepted: 01/05/2022] [Indexed: 01/23/2023] Open
Abstract
Insulin receptor (Insr) protein is present at higher levels in pancreatic β-cells than in most other tissues, but the consequences of β-cell insulin resistance remain enigmatic. Here, we use an Ins1cre knock-in allele to delete Insr specifically in β-cells of both female and male mice. We compare experimental mice to Ins1cre-containing littermate controls at multiple ages and on multiple diets. RNA-seq of purified recombined β-cells reveals transcriptomic consequences of Insr loss, which differ between female and male mice. Action potential and calcium oscillation frequencies are increased in Insr knockout β-cells from female, but not male mice, whereas only male βInsrKO islets have reduced ATP-coupled oxygen consumption rate and reduced expression of genes involved in ATP synthesis. Female βInsrKO and βInsrHET mice exhibit elevated insulin release in ex vivo perifusion experiments, during hyperglycemic clamps, and following i.p. glucose challenge. Deletion of Insr does not alter β-cell area up to 9 months of age, nor does it impair hyperglycemia-induced proliferation. Based on our data, we adapt a mathematical model to include β-cell insulin resistance, which predicts that β-cell Insr knockout improves glucose tolerance depending on the degree of whole-body insulin resistance. Indeed, glucose tolerance is significantly improved in female βInsrKO and βInsrHET mice compared to controls at 9, 21 and 39 weeks, and also in insulin-sensitive 4-week old males. We observe no improved glucose tolerance in older male mice or in high fat diet-fed mice, corroborating the prediction that global insulin resistance obscures the effects of β-cell specific insulin resistance. The propensity for hyperinsulinemia is associated with mildly reduced fasting glucose and increased body weight. We further validate our main in vivo findings using an Ins1-CreERT transgenic line and find that male mice have improved glucose tolerance 4 weeks after tamoxifen-mediated Insr deletion. Collectively, our data show that β-cell insulin resistance in the form of reduced β-cell Insr contributes to hyperinsulinemia in the context of glucose stimulation, thereby improving glucose homeostasis in otherwise insulin sensitive sex, dietary and age contexts.
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Affiliation(s)
- Søs Skovsø
- Diabetes Research Group, Life Sciences Institute, and Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, BC, Canada
| | - Evgeniy Panzhinskiy
- Diabetes Research Group, Life Sciences Institute, and Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, BC, Canada
| | - Jelena Kolic
- Diabetes Research Group, Life Sciences Institute, and Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, BC, Canada
| | - Haoning Howard Cen
- Diabetes Research Group, Life Sciences Institute, and Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, BC, Canada
| | - Derek A Dionne
- Diabetes Research Group, Life Sciences Institute, and Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, BC, Canada
| | - Xiao-Qing Dai
- Alberta Diabetes Institute and Department of Pharmacology, University of Alberta, Edmonton, Canada
| | - Rohit B Sharma
- Division of Endocrinology, Diabetes and Metabolism and the Weill Center for Metabolic Health, Weill Cornell Medicine, New York, NY, USA
| | - Lynda Elghazi
- Department of Ophthalmology and Visual Sciences, University of Michigan Kellogg Eye Center, Ann Arbor, MI, USA
| | - Cara E Ellis
- Diabetes Research Group, Life Sciences Institute, and Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, BC, Canada
| | - Katharine Faulkner
- Department of Mathematics, University of British Columbia, Vancouver, BC, Canada
| | - Stephanie A M Marcil
- Diabetes Research Group, Life Sciences Institute, and Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, BC, Canada
| | - Peter Overby
- Diabetes Research Group, Life Sciences Institute, and Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, BC, Canada
| | - Nilou Noursadeghi
- Diabetes Research Group, Life Sciences Institute, and Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, BC, Canada
| | - Daria Hutchinson
- Diabetes Research Group, Life Sciences Institute, and Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, BC, Canada
| | - Xiaoke Hu
- Diabetes Research Group, Life Sciences Institute, and Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, BC, Canada
| | - Hong Li
- Diabetes Research Group, Life Sciences Institute, and Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, BC, Canada
| | - Honey Modi
- Diabetes Research Group, Life Sciences Institute, and Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, BC, Canada
| | - Jennifer S Wildi
- Diabetes Research Group, Life Sciences Institute, and Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, BC, Canada
| | - J Diego Botezelli
- Diabetes Research Group, Life Sciences Institute, and Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, BC, Canada
| | - Hye Lim Noh
- Program in Molecular Medicine University of Massachusetts Medical School, Worcester, MA, USA
- Charles River Laboratories, Shrewsbury, MA, USA
| | - Sujin Suk
- Program in Molecular Medicine University of Massachusetts Medical School, Worcester, MA, USA
| | - Brian Gablaski
- Division of Endocrinology, Diabetes and Metabolism, Department of Medicine, University of Massachusetts Medical School, Worcester, MA, USA
- Charles River Laboratories, Shrewsbury, MA, USA
| | - Austin Bautista
- Alberta Diabetes Institute and Department of Pharmacology, University of Alberta, Edmonton, Canada
| | - Ryekjang Kim
- Alberta Diabetes Institute and Department of Pharmacology, University of Alberta, Edmonton, Canada
| | - Corentin Cras-Méneur
- Department of Internal Medicine, Division of Metabolism, Endocrinology and Diabetes, University of Michigan, Ann Arbor, MI, USA
| | - Stephane Flibotte
- UBC Life Sciences Institute Bioinformatics Facility, University of British Columbia, Vancouver, BC, Canada
| | - Sunita Sinha
- UBC Sequencing and Bioinformatics Consortium, Pharmaceutical Sciences, University of British Columbia, Vancouver, BC, Canada
| | - Dan S Luciani
- BC Children's Hospital Research Institute, Department of Surgery, Faculty of Medicine, University of British Columbia, Vancouver, BC, Canada
| | - Corey Nislow
- UBC Sequencing and Bioinformatics Consortium, Pharmaceutical Sciences, University of British Columbia, Vancouver, BC, Canada
| | - Elizabeth J Rideout
- Diabetes Research Group, Life Sciences Institute, and Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, BC, Canada
| | - Eric N Cytrynbaum
- Department of Mathematics, University of British Columbia, Vancouver, BC, Canada
| | - Jason K Kim
- Program in Molecular Medicine University of Massachusetts Medical School, Worcester, MA, USA
- Division of Endocrinology, Diabetes and Metabolism, Department of Medicine, University of Massachusetts Medical School, Worcester, MA, USA
| | - Ernesto Bernal-Mizrachi
- Division of Endocrinology, Diabetes and Metabolism, University of Miami Miller School of Medicine and Miami VA Health Care System, Miami, FL, USA
| | - Laura C Alonso
- Division of Endocrinology, Diabetes and Metabolism and the Weill Center for Metabolic Health, Weill Cornell Medicine, New York, NY, USA
| | - Patrick E MacDonald
- Alberta Diabetes Institute and Department of Pharmacology, University of Alberta, Edmonton, Canada
| | - James D Johnson
- Diabetes Research Group, Life Sciences Institute, and Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, BC, Canada.
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13
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Aggarwal R, Peng Z, Zeng N, Silva J, He L, Chen J, Debebe A, Tu T, Alba M, Chen CY, Stiles EX, Hong H, Stiles BL. Chronic Exposure to Palmitic Acid Down-Regulates AKT in Beta-Cells through Activation of mTOR. THE AMERICAN JOURNAL OF PATHOLOGY 2022; 192:130-145. [PMID: 34619135 PMCID: PMC8759041 DOI: 10.1016/j.ajpath.2021.09.008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/21/2021] [Revised: 09/09/2021] [Accepted: 09/22/2021] [Indexed: 01/03/2023]
Abstract
High circulating lipids occurring in obese individuals and insulin-resistant patients are considered a contributing factor to type 2 diabetes. Exposure to high lipid concentration is proposed to both protect and damage beta-cells under different circumstances. Here, by feeding mice a high-fat diet (HFD) for 2 weeks to up to 14 months, the study showed that HFD initially causes the beta-cells to expand in population, whereas long-term exposure to HFD is associated with failure of beta-cells and the inability of animals to respond to glucose challenge. To prevent the failure of beta-cells and the development of type 2 diabetes, the molecular mechanisms that underlie this biphasic response of beta-cells to lipid exposure were explored. Using palmitic acid (PA) in cultured beta-cells and islets, the study demonstrated that chronic exposure to lipids leads to reduced viability and inhibition of cell cycle progression concurrent with down-regulation of a pro-growth/survival kinase AKT, independent of glucose. This AKT down-regulation by PA is correlated with the induction of mTOR/S6K activity. Inhibiting mTOR activity with rapamycin induced Raptor and restored AKT activity, allowing beta-cells to gain proliferation capacity that was lost after HFD exposure. In summary, a novel mechanism in which lipid exposure may cause the dipole effects on beta-cell growth was elucidated, where mTOR acts as a lipid sensor. These mechanisms can be novel targets for future therapeutic developments.
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Affiliation(s)
- Richa Aggarwal
- Department of Pharmacology and Pharmaceutical Sciences, School of Pharmacy, University of Southern California, Los Angeles, California
| | - Zhechu Peng
- Department of Pharmacology and Pharmaceutical Sciences, School of Pharmacy, University of Southern California, Los Angeles, California
| | - Ni Zeng
- Department of Pharmacology and Pharmaceutical Sciences, School of Pharmacy, University of Southern California, Los Angeles, California
| | - Joshua Silva
- Department of Pharmacology and Pharmaceutical Sciences, School of Pharmacy, University of Southern California, Los Angeles, California
| | - Lina He
- Department of Pharmacology and Pharmaceutical Sciences, School of Pharmacy, University of Southern California, Los Angeles, California
| | - Jingyu Chen
- Department of Pharmacology and Pharmaceutical Sciences, School of Pharmacy, University of Southern California, Los Angeles, California
| | - Anketse Debebe
- Department of Pharmacology and Pharmaceutical Sciences, School of Pharmacy, University of Southern California, Los Angeles, California
| | - Taojian Tu
- Department of Pharmacology and Pharmaceutical Sciences, School of Pharmacy, University of Southern California, Los Angeles, California
| | - Mario Alba
- Department of Pharmacology and Pharmaceutical Sciences, School of Pharmacy, University of Southern California, Los Angeles, California
| | - Chien-Yu Chen
- Department of Pharmacology and Pharmaceutical Sciences, School of Pharmacy, University of Southern California, Los Angeles, California
| | - Eileen X. Stiles
- Department of Pharmacology and Pharmaceutical Sciences, School of Pharmacy, University of Southern California, Los Angeles, California
| | - Handan Hong
- Department of Pharmacology and Pharmaceutical Sciences, School of Pharmacy, University of Southern California, Los Angeles, California
| | - Bangyan L. Stiles
- Department of Pharmacology and Pharmaceutical Sciences, School of Pharmacy, University of Southern California, Los Angeles, California,Department of Pathology, Keck School of Medicine, University of Southern California, Los Angeles, California,Address correspondence to Bangyan L. Stiles, Ph.D., Department of Pharmacology and Pharmaceutical Sciences, School of Pharmacy, University of Southern California, Los Angeles, CA 90033.
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14
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Mei W, Zhu B, Shu Y, Liang Y, Lin M, He M, Luo H, Ye J. GDF11 protects against glucotoxicity-induced mice retinal microvascular endothelial cell dysfunction and diabetic retinopathy disease. Mol Cell Endocrinol 2021; 537:111422. [PMID: 34391845 DOI: 10.1016/j.mce.2021.111422] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/22/2020] [Revised: 08/08/2021] [Accepted: 08/10/2021] [Indexed: 10/20/2022]
Abstract
Growth differentiation factor 11 (GDF11) has been implicated in the regulation of embryonic development and age-related dysfunction, including the regulation of retinal progenitor cells. However, little is known about the functions of GDF11 in diabetic retinopathy. In this study, we demonstrated that GDF11 treatment improved diabetes-induced retinal cell death, capillary degeneration, pericyte loss, inflammation, and blood-retinal barrier breakdown in mice. Treatment of isolated mouse retinal microvascular endothelial cells with recombinant GDF11 in vitro attenuated glucotoxicity-induced retinal endothelial apoptosis and the inflammatory response. The protective mechanisms exerted are associated with TGF-β/Smad2, PI3k-Akt-FoxO1 activation,and NF-κB pathway inhibition. This study indicated that GDF11 is a novel therapeutic target for diabetic retinopathy.
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Affiliation(s)
- Wen Mei
- Department of Endocrinology, Nanhai District People's Hospital of Foshan, Foping Road 40, Foshan, 528200, Guangdong Province, China; Department of Endocrinology, Wuhan Fourth Hospital, Puai Hospital, Tongji Medical College, Huazhong University of Science and Technology, Hanzheng Road 473, Wuhan, 430070, Hubei Province, China
| | - Biao Zhu
- Department of Stomatology, Fuxing Hospital, Capital Medical University, Fuxingmen Wai Street A 20, Beijing, 100038, China
| | - Yi Shu
- Department of Endocrinology, Nanhai District People's Hospital of Foshan, Foping Road 40, Foshan, 528200, Guangdong Province, China
| | - Yanhua Liang
- Department of Ophthalmology, People's Hospital of Jiangmen, Penglai Road 19, Jiangmen, 529000, Guangdong Province, China
| | - Mei Lin
- Department of Endocrinology, Wuhan Fourth Hospital, Puai Hospital, Tongji Medical College, Huazhong University of Science and Technology, Hanzheng Road 473, Wuhan, 430070, Hubei Province, China.
| | - Mingjuan He
- Department of Endocrinology, Wuhan Fourth Hospital, Puai Hospital, Tongji Medical College, Huazhong University of Science and Technology, Hanzheng Road 473, Wuhan, 430070, Hubei Province, China
| | - Haizhao Luo
- Department of Endocrinology, Nanhai District People's Hospital of Foshan, Foping Road 40, Foshan, 528200, Guangdong Province, China
| | - Jingwen Ye
- Department of Endocrinology, Nanhai District People's Hospital of Foshan, Foping Road 40, Foshan, 528200, Guangdong Province, China
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15
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Pancreatic β-Cell O-GlcNAc Transferase Overexpression Increases Susceptibility to Metabolic Stressors in Female Mice. Cells 2021; 10:cells10102801. [PMID: 34685781 PMCID: PMC8534823 DOI: 10.3390/cells10102801] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2021] [Revised: 10/14/2021] [Accepted: 10/14/2021] [Indexed: 01/21/2023] Open
Abstract
The nutrient-sensor O-GlcNAc transferase (Ogt), the sole enzyme that adds an O-GlcNAc-modification onto proteins, plays a critical role for pancreatic β-cell survival and insulin secretion. We hypothesized that β-cell Ogt overexpression would confer protection from β-cell failure in response to metabolic stressors, such as high-fat diet (HFD) and streptozocin (STZ). Here, we generated a β-cell-specific Ogt in overexpressing (βOgtOE) mice, where a significant increase in Ogt protein level and O-GlcNAc-modification of proteins were observed in islets under a normal chow diet. We uncovered that βOgtOE mice show normal peripheral insulin sensitivity and glucose tolerance with a regular chow diet. However, when challenged with an HFD, only female βOgtOE (homozygous) Hz mice developed a mild glucose intolerance, despite increased insulin secretion and normal β-cell mass. While female mice are normally resistant to low-dose STZ treatments, the βOgtOE Hz mice developed hyperglycemia and glucose intolerance post-STZ treatment. Transcriptome analysis between islets with loss or gain of Ogt by RNA sequencing shows common altered pathways involving pro-survival Erk and Akt and inflammatory regulators IL1β and NFkβ. Together, these data show a possible gene dosage effect of Ogt and the importance O-GlcNAc cycling in β-cell survival and function to regulate glucose homeostasis.
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16
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Altman MK, Schaub CM, Dadi PK, Dickerson MT, Zaborska KE, Nakhe AY, Graff SM, Galletta TJ, Amarnath G, Thorson AS, Gu G, Jacobson DA. TRPM7 is a crucial regulator of pancreatic endocrine development and high-fat-diet-induced β-cell proliferation. Development 2021; 148:271182. [PMID: 34345920 DOI: 10.1242/dev.194928] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2020] [Accepted: 07/20/2021] [Indexed: 12/31/2022]
Abstract
The melastatin subfamily of the transient receptor potential channels (TRPM) are regulators of pancreatic β-cell function. TRPM7 is the most abundant islet TRPM channel; however, the role of TRPM7 in β-cell function has not been determined. Here, we used various spatiotemporal transgenic mouse models to investigate how TRPM7 knockout influences pancreatic endocrine development, proliferation and function. Ablation of TRPM7 within pancreatic progenitors reduced pancreatic size, and α-cell and β-cell mass. This resulted in modestly impaired glucose tolerance. However, TRPM7 ablation following endocrine specification or in adult mice did not impact endocrine expansion or glucose tolerance. As TRPM7 regulates cell proliferation, we assessed how TRPM7 influences β-cell hyperplasia under insulin-resistant conditions. β-Cell proliferation induced by high-fat diet was significantly decreased in TRPM7-deficient β-cells. The endocrine roles of TRPM7 may be influenced by cation flux through the channel, and indeed we found that TRPM7 ablation altered β-cell Mg2+ and reduced the magnitude of elevation in β-cell Mg2+ during proliferation. Together, these findings revealed that TRPM7 controls pancreatic development and β-cell proliferation, which is likely due to regulation of Mg2+ homeostasis.
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Affiliation(s)
- Molly K Altman
- Department of Molecular Physiology and Biophysics, Vanderbilt University, 7425B MRB IV, 2213 Garland Ave., Nashville, TN 37232, USA
| | - Charles M Schaub
- Department of Molecular Physiology and Biophysics, Vanderbilt University, 7425B MRB IV, 2213 Garland Ave., Nashville, TN 37232, USA
| | - Prasanna K Dadi
- Department of Molecular Physiology and Biophysics, Vanderbilt University, 7425B MRB IV, 2213 Garland Ave., Nashville, TN 37232, USA
| | - Matthew T Dickerson
- Department of Molecular Physiology and Biophysics, Vanderbilt University, 7425B MRB IV, 2213 Garland Ave., Nashville, TN 37232, USA
| | - Karolina E Zaborska
- Department of Molecular Physiology and Biophysics, Vanderbilt University, 7425B MRB IV, 2213 Garland Ave., Nashville, TN 37232, USA
| | - Arya Y Nakhe
- Department of Molecular Physiology and Biophysics, Vanderbilt University, 7425B MRB IV, 2213 Garland Ave., Nashville, TN 37232, USA
| | - Sarah M Graff
- Department of Molecular Physiology and Biophysics, Vanderbilt University, 7425B MRB IV, 2213 Garland Ave., Nashville, TN 37232, USA
| | - Thomas J Galletta
- Department of Molecular Physiology and Biophysics, Vanderbilt University, 7425B MRB IV, 2213 Garland Ave., Nashville, TN 37232, USA
| | - Gautami Amarnath
- Department of Molecular Physiology and Biophysics, Vanderbilt University, 7425B MRB IV, 2213 Garland Ave., Nashville, TN 37232, USA.,Molecular Neurophysiology, Institute of Applied Physiology, University of Ulm, 89081 Ulm, Germany
| | - Ariel S Thorson
- Department of Molecular Physiology and Biophysics, Vanderbilt University, 7425B MRB IV, 2213 Garland Ave., Nashville, TN 37232, USA
| | - Guoqiang Gu
- Vanderbilt Program in Developmental Biology, Vanderbilt Center for Stem Cell Biology, Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - David A Jacobson
- Department of Molecular Physiology and Biophysics, Vanderbilt University, 7425B MRB IV, 2213 Garland Ave., Nashville, TN 37232, USA
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17
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Long-Chain Acylcarnitines Decrease the Phosphorylation of the Insulin Receptor at Tyr1151 Through a PTP1B-Dependent Mechanism. Int J Mol Sci 2021; 22:ijms22126470. [PMID: 34208786 PMCID: PMC8235348 DOI: 10.3390/ijms22126470] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2021] [Revised: 06/11/2021] [Accepted: 06/14/2021] [Indexed: 01/26/2023] Open
Abstract
The accumulation of lipid intermediates may interfere with energy metabolism pathways and regulate cellular energy supplies. As increased levels of long-chain acylcarnitines have been linked to insulin resistance, we investigated the effects of long-chain acylcarnitines on key components of the insulin signalling pathway. We discovered that palmitoylcarnitine induces dephosphorylation of the insulin receptor (InsR) through increased activity of protein tyrosine phosphatase 1B (PTP1B). Palmitoylcarnitine suppresses protein kinase B (Akt) phosphorylation at Ser473, and this effect is not alleviated by the inhibition of PTP1B by the insulin sensitizer bis-(maltolato)-oxovanadium (IV). This result indicates that palmitoylcarnitine affects Akt activity independently of the InsR phosphorylation level. Inhibition of protein kinase C and protein phosphatase 2A does not affect the palmitoylcarnitine-mediated inhibition of Akt Ser473 phosphorylation. Additionally, palmitoylcarnitine markedly stimulates insulin release by suppressing Akt Ser473 phosphorylation in insulin-secreting RIN5F cells. In conclusion, long-chain acylcarnitines activate PTP1B and decrease InsR Tyr1151 phosphorylation and Akt Ser473 phosphorylation, thus limiting the cellular response to insulin stimulation.
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Lee D, Kim KH, Jang TS, Kang KS. Identification of bioactive compounds from mulberry enhancing glucose-stimulated insulin secretion. Bioorg Med Chem Lett 2021; 43:128096. [PMID: 33984475 DOI: 10.1016/j.bmcl.2021.128096] [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: 03/25/2021] [Revised: 04/29/2021] [Accepted: 05/05/2021] [Indexed: 10/21/2022]
Abstract
Previously, we isolated six heterocyclic compounds (1-6) from the fruits of mulberry trees (Morus alba L.) and determined that loliolide affords rat pancreatic islet β-cell (INS-1) protection against streptozotocin‑induced cytotoxicity. In the present study, we further investigated the effect of the six heterocyclic compounds (1-6) on glucose-stimulated insulin secretion (GSIS) in INS-1 cells. Among them, (R)‑5‑hydroxypyrrolidin‑2‑one(1) and indole (6) increased GSIS without inducing cytotoxicity. Additionally, compounds 1 and 6 enhanced the phosphorylation of total insulin receptor substrate-2, phosphatidylinositol 3-kinase, and Akt, and activated pancreatic and duodenal homeobox-1, which play a crucial role in β-cell functions related to insulin secretion. Collectively, these findings indicate that (R)‑5‑hydroxypyrrolidin‑2‑one(1) and indole (6), isolated from M. alba fruits, may be beneficial in managing type 2 diabetes.
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Affiliation(s)
- Dahae Lee
- College of Korean Medicine, Gachon University, Seongnam 13120, Republic of Korea
| | - Ki Hyun Kim
- School of Pharmacy, Sungkyunkwan University, Suwon, Gyeonggi-do 16419, Republic of Korea
| | - Tae Su Jang
- Department of Medicine, Dankook University, Cheonan, Chungnam 31116, Republic of Korea.
| | - Ki Sung Kang
- College of Korean Medicine, Gachon University, Seongnam 13120, Republic of Korea.
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Šrámek J, Němcová-Fürstová V, Kovář J. Molecular Mechanisms of Apoptosis Induction and Its Regulation by Fatty Acids in Pancreatic β-Cells. Int J Mol Sci 2021; 22:4285. [PMID: 33924206 PMCID: PMC8074590 DOI: 10.3390/ijms22084285] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2021] [Revised: 04/09/2021] [Accepted: 04/16/2021] [Indexed: 02/06/2023] Open
Abstract
Pancreatic β-cell failure and death contribute significantly to the pathogenesis of type 2 diabetes. One of the main factors responsible for β-cell dysfunction and subsequent cell death is chronic exposure to increased concentrations of FAs (fatty acids). The effect of FAs seems to depend particularly on the degree of their saturation. Saturated FAs induce apoptosis in pancreatic β-cells, whereas unsaturated FAs are well tolerated and are even capable of inhibiting the pro-apoptotic effect of saturated FAs. Molecular mechanisms of apoptosis induction by saturated FAs in β-cells are not completely elucidated. Saturated FAs induce ER stress, which in turn leads to activation of all ER stress pathways. When ER stress is severe or prolonged, apoptosis is induced. The main mediator seems to be the CHOP transcription factor. Via regulation of expression/activity of pro- and anti-apoptotic Bcl-2 family members, and potentially also through the increase in ROS production, CHOP switches on the mitochondrial pathway of apoptosis induction. ER stress signalling also possibly leads to autophagy signalling, which may activate caspase-8. Saturated FAs activate or inhibit various signalling pathways, i.e., p38 MAPK signalling, ERK signalling, ceramide signalling, Akt signalling and PKCδ signalling. This may lead to the activation of the mitochondrial pathway of apoptosis, as well. Particularly, the inhibition of the pro-survival Akt signalling seems to play an important role. This inhibition may be mediated by multiple pathways (e.g., ER stress signalling, PKCδ and ceramide) and could also consequence in autophagy signalling. Experimental evidence indicates the involvement of certain miRNAs in mechanisms of FA-induced β-cell apoptosis, as well. In the rather rare situations when unsaturated FAs are also shown to be pro-apoptotic, the mechanisms mediating this effect in β-cells seem to be the same as for saturated FAs. To conclude, FA-induced apoptosis rather appears to be preceded by complex cross talks of multiple signalling pathways. Some of these pathways may be regulated by decreased membrane fluidity due to saturated FA incorporation. Few data are available concerning molecular mechanisms mediating the protective effect of unsaturated FAs on the effect of saturated FAs. It seems that the main possible mechanism represents a rather inhibitory intervention into saturated FA-induced pro-apoptotic signalling than activation of some pro-survival signalling pathway(s) or metabolic interference in β-cells. This inhibitory intervention may be due to an increase of membrane fluidity.
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Affiliation(s)
- Jan Šrámek
- Department of Biochemistry, Cell and Molecular Biology & Center for Research of Diabetes, Metabolism and Nutrition, Third Faculty of Medicine, Charles University, Ruská 87, 100 00 Prague, Czech Republic;
| | - Vlasta Němcová-Fürstová
- Department of Biochemistry, Cell and Molecular Biology & Center for Research of Diabetes, Metabolism and Nutrition, Third Faculty of Medicine, Charles University, Ruská 87, 100 00 Prague, Czech Republic;
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Arous C, Mizgier ML, Rickenbach K, Pinget M, Bouzakri K, Wehrle-Haller B. Integrin and autocrine IGF2 pathways control fasting insulin secretion in β-cells. J Biol Chem 2020; 295:16510-16528. [PMID: 32934005 PMCID: PMC7864053 DOI: 10.1074/jbc.ra120.012957] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2020] [Revised: 08/09/2020] [Indexed: 12/20/2022] Open
Abstract
Elevated levels of fasting insulin release and insufficient glucose-stimulated insulin secretion (GSIS) are hallmarks of diabetes. Studies have established cross-talk between integrin signaling and insulin activity, but more details of how integrin-dependent signaling impacts the pathophysiology of diabetes are needed. Here, we dissected integrin-dependent signaling pathways involved in the regulation of insulin secretion in β-cells and studied their link to the still debated autocrine regulation of insulin secretion by insulin/insulin-like growth factor (IGF) 2-AKT signaling. We observed for the first time a cooperation between different AKT isoforms and focal adhesion kinase (FAK)-dependent adhesion signaling, which either controlled GSIS or prevented insulin secretion under fasting conditions. Indeed, β-cells form integrin-containing adhesions, which provide anchorage to the pancreatic extracellular matrix and are the origin of intracellular signaling via FAK and paxillin. Under low-glucose conditions, β-cells adopt a starved adhesion phenotype consisting of actin stress fibers and large peripheral focal adhesion. In contrast, glucose stimulation induces cell spreading, actin remodeling, and point-like adhesions that contain phospho-FAK and phosphopaxillin, located in small protrusions. Rat primary β-cells and mouse insulinomas showed an adhesion remodeling during GSIS resulting from autocrine insulin/IGF2 and AKT1 signaling. However, under starving conditions, the maintenance of stress fibers and the large adhesion phenotype required autocrine IGF2-IGF1 receptor signaling mediated by AKT2 and elevated FAK-kinase activity and ROCK-RhoA levels but low levels of paxillin phosphorylation. This starved adhesion phenotype prevented excessive insulin granule release to maintain low insulin secretion during fasting. Thus, deregulation of the IGF2 and adhesion-mediated signaling may explain dysfunctions observed in diabetes.
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Affiliation(s)
- Caroline Arous
- Department of Cell Physiology and Metabolism, Centre Médical Universitaire, University of Geneva, Geneva, Switzerland.
| | - Maria Luisa Mizgier
- UMR DIATHEC, Centre Européen d'Etude du Diabète, UMR DIATHEC, Strasbourg, France
| | - Katharina Rickenbach
- Department of Cell Physiology and Metabolism, Centre Médical Universitaire, University of Geneva, Geneva, Switzerland
| | - Michel Pinget
- UMR DIATHEC, Centre Européen d'Etude du Diabète, UMR DIATHEC, Strasbourg, France
| | - Karim Bouzakri
- UMR DIATHEC, Centre Européen d'Etude du Diabète, UMR DIATHEC, Strasbourg, France
| | - Bernhard Wehrle-Haller
- Department of Cell Physiology and Metabolism, Centre Médical Universitaire, University of Geneva, Geneva, Switzerland
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21
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Sharma R, Martins N, Chaudhary A, Garg N, Sharma V, Kuca K, Nepovimova E, Tuli HS, Bishayee A, Chaudhary A, Prajapati PK. Adjunct use of honey in diabetes mellitus: A consensus or conundrum? Trends Food Sci Technol 2020. [DOI: 10.1016/j.tifs.2020.10.020] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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22
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Kolic J, Beet L, Overby P, Cen HH, Panzhinskiy E, Ure DR, Cross JL, Huizinga RB, Johnson JD. Differential Effects of Voclosporin and Tacrolimus on Insulin Secretion From Human Islets. Endocrinology 2020; 161:5902465. [PMID: 32894758 PMCID: PMC7567406 DOI: 10.1210/endocr/bqaa162] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Accepted: 09/02/2020] [Indexed: 12/16/2022]
Abstract
The incidence of new onset diabetes after transplant (NODAT) has increased over the past decade, likely due to calcineurin inhibitor-based immunosuppressants, including tacrolimus (TAC) and cyclosporin. Voclosporin (VCS), a next-generation calcineurin inhibitor, is reported to cause fewer incidences of NODAT but the reason is unclear. While calcineurin signaling plays important roles in pancreatic β-cell survival, proliferation, and function, its effects on human β-cells remain understudied. In particular, we do not understand why some calcineurin inhibitors have more profound effects on the incidence of NODAT. We compared the effects of TAC and VCS on the dynamics of insulin secretory function, programmed cell death rate, and the transcriptomic profile of human islets. We studied 2 clinically relevant doses of TAC (10 ng/mL, 30 ng/mL) and VCS (20 ng/mL, 60 ng/mL), meant to approximate the clinical trough and peak concentrations. TAC, but not VCS, caused a significant impairment of 15 mM glucose-stimulated and 30 mM KCl-stimulated insulin secretion. This points to molecular defects in the distal stages of exocytosis after voltage-gated Ca2+ entry. No significant effects on islet cell survival or total insulin content were identified. RNA sequencing showed that TAC significantly decreased the expression of 17 genes, including direct and indirect regulators of exocytosis (SYT16, TBC1D30, PCK1, SMOC1, SYT5, PDK4, and CREM), whereas VCS has less broad, and milder, effects on gene expression. Clinically relevant doses of TAC, but not VCS, directly inhibit insulin secretion from human islets, likely via transcriptional control of exocytosis machinery.
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Affiliation(s)
- Jelena Kolic
- Diabetes Research Group, Life Sciences Institute, Department of Cellular and Physiological Sciences & Department of Surgery, University of British Columbia, Vancouver, Canada
| | - Leanne Beet
- Diabetes Research Group, Life Sciences Institute, Department of Cellular and Physiological Sciences & Department of Surgery, University of British Columbia, Vancouver, Canada
| | - Peter Overby
- Diabetes Research Group, Life Sciences Institute, Department of Cellular and Physiological Sciences & Department of Surgery, University of British Columbia, Vancouver, Canada
| | - Haoning Howard Cen
- Diabetes Research Group, Life Sciences Institute, Department of Cellular and Physiological Sciences & Department of Surgery, University of British Columbia, Vancouver, Canada
| | - Evgeniy Panzhinskiy
- Diabetes Research Group, Life Sciences Institute, Department of Cellular and Physiological Sciences & Department of Surgery, University of British Columbia, Vancouver, Canada
| | - Daren R Ure
- Hepion Pharmaceuticals, Edmonton, Alberta, Canada
| | | | | | - James D Johnson
- Correspondence: Professor James D. Johnson, PhD, Faculty of Medicine, Department of Cellular and Physiological Sciences & Department of Surgery, The University of British Columbia, Life Sciences Institute, 5358 – 2350 Health Sciences Mall, Vancouver, British Columbia, Canada, V6T 1Z3. E-mail: ; Twitter: @JimJohnsonSci
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Yagubova SS, Ostrovskaya RU, Gudasheva TA, Seredenin SB. The PI3K/Akt Cascade Is Involved in the Antidiabetic Effect of Compound GSB-214, a Low-Molecular-Weight BDNF Mimetic. Bull Exp Biol Med 2020; 169:771-774. [DOI: 10.1007/s10517-020-04975-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2019] [Indexed: 11/27/2022]
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Metabolic Effects of Selective Deletion of Group VIA Phospholipase A 2 from Macrophages or Pancreatic Islet Beta-Cells. Biomolecules 2020; 10:biom10101455. [PMID: 33080873 PMCID: PMC7602969 DOI: 10.3390/biom10101455] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2020] [Revised: 10/08/2020] [Accepted: 10/13/2020] [Indexed: 12/11/2022] Open
Abstract
To examine the role of group VIA phospholipase A2 (iPLA2β) in specific cell lineages in insulin secretion and insulin action, we prepared mice with a selective iPLA2β deficiency in cells of myelomonocytic lineage, including macrophages (MØ-iPLA2β-KO), or in insulin-secreting β-cells (β-Cell-iPLA2β-KO), respectively. MØ-iPLA2β-KO mice exhibited normal glucose tolerance when fed standard chow and better glucose tolerance than floxed-iPLA2β control mice after consuming a high-fat diet (HFD). MØ-iPLA2β-KO mice exhibited normal glucose-stimulated insulin secretion (GSIS) in vivo and from isolated islets ex vivo compared to controls. Male MØ-iPLA2β-KO mice exhibited enhanced insulin responsivity vs. controls after a prolonged HFD. In contrast, β-cell-iPLA2β-KO mice exhibited impaired glucose tolerance when fed standard chow, and glucose tolerance deteriorated further when introduced to a HFD. β-Cell-iPLA2β-KO mice exhibited impaired GSIS in vivo and from isolated islets ex vivo vs. controls. β-Cell-iPLA2β-KO mice also exhibited an enhanced insulin responsivity compared to controls. These findings suggest that MØ iPLA2β participates in HFD-induced deterioration in glucose tolerance and that this mainly reflects an effect on insulin responsivity rather than on insulin secretion. In contrast, β-cell iPLA2β plays a role in GSIS and also appears to confer some protection against deterioration in β-cell functions induced by a HFD.
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Alejandro EU, Jo S, Akhaphong B, Llacer PR, Gianchandani M, Gregg B, Parlee SD, MacDougald OA, Bernal-Mizrachi E. Maternal low-protein diet on the last week of pregnancy contributes to insulin resistance and β-cell dysfunction in the mouse offspring. Am J Physiol Regul Integr Comp Physiol 2020; 319:R485-R496. [PMID: 32877242 PMCID: PMC7717124 DOI: 10.1152/ajpregu.00284.2019] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2019] [Revised: 08/17/2020] [Accepted: 08/17/2020] [Indexed: 12/17/2022]
Abstract
Maternal low-protein diet (LP) throughout gestation affects pancreatic β-cell fraction of the offspring at birth, thus increasing their susceptibility to metabolic dysfunction and type 2 diabetes in adulthood. The present study sought to strictly examine the effects of LP during the last week of gestation (LP12.5) alone as a developmental window for β-cell programming and metabolic dysfunction in adulthood. Islet morphology analysis revealed normal β-cell fraction in LP12.5 newborns. Normal glucose tolerance was observed in 6- to 8-wk-old male and female LP12.5 offspring. However, male LP12.5 offspring displayed glucose intolerance and reduced insulin sensitivity associated with β-cell dysfunction with aging. High-fat diet exposure of metabolically normal 12-wk-old male LP12.5 induced glucose intolerance due to increased body weight, insulin resistance, and insufficient β-cell mass adaptation despite higher insulin secretion. Assessment of epigenetic mechanisms through microRNAs (miRs) by a real-time PCR-based microarray in islets revealed elevation in miRs that regulate insulin secretion (miRs 342, 143), insulin resistance (miR143), and obesity (miR219). In the islets, overexpression of miR143 reduced insulin secretion in response to glucose. In contrast to the model of LP exposure throughout pregnancy, islet protein levels of mTOR and pancreatic and duodenal homeobox 1 were normal in LP12.5 islets. Collectively, these data suggest that LP diet during the last week of pregnancy is critical and sufficient to induce specific and distinct developmental programming effects of tissues that control glucose homeostasis, thus causing permanent changes in specific set of microRNAs that may contribute to the overall vulnerability of the offspring to obesity, insulin resistance, and type 2 diabetes.
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Affiliation(s)
- Emilyn U Alejandro
- Department of Integrative Biology and Physiology, University of Minnesota, Minneapolis, Minnesota
- Division of Metabolism, Endocrinology, and Diabetes, Department of Internal Medicine, Brehm Center for Diabetes Research, University of Michigan Medical School, Ann Arbor, Michigan
| | - Seokwon Jo
- Department of Integrative Biology and Physiology, University of Minnesota, Minneapolis, Minnesota
| | - Brian Akhaphong
- Department of Integrative Biology and Physiology, University of Minnesota, Minneapolis, Minnesota
| | - Pau Romaguera Llacer
- Division of Endocrinology, Metabolism and Diabetes, University of Miami, Miami, Florida
| | - Maya Gianchandani
- Division of Metabolism, Endocrinology, and Diabetes, Department of Internal Medicine, Brehm Center for Diabetes Research, University of Michigan Medical School, Ann Arbor, Michigan
| | - Brigid Gregg
- Department of Pediatrics, University of Michigan Medical School, Ann Arbor, Michigan
| | - Sebastian D Parlee
- Department of Molecular & Integrative Physiology, University of Michigan Medical School, Ann Arbor, Michigan
| | - Ormond A MacDougald
- Department of Molecular & Integrative Physiology, University of Michigan Medical School, Ann Arbor, Michigan
| | - Ernesto Bernal-Mizrachi
- Division of Metabolism, Endocrinology, and Diabetes, Department of Internal Medicine, Brehm Center for Diabetes Research, University of Michigan Medical School, Ann Arbor, Michigan
- Veterans Affairs Ann Arbor Healthcare System, Ann Arbor, Michigan
- Miami Veterans Affairs Healthcare System University of Miami, Miami, Florida
- Division of Endocrinology, Metabolism and Diabetes, University of Miami, Miami, Florida
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26
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Gudasheva TA, Povarnina PY, Tarasiuk AV, Seredenin SB. Low-molecular mimetics of nerve growth factor and brain-derived neurotrophic factor: Design and pharmacological properties. Med Res Rev 2020; 41:2746-2774. [PMID: 32808322 DOI: 10.1002/med.21721] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2020] [Revised: 08/02/2020] [Accepted: 08/05/2020] [Indexed: 12/20/2022]
Abstract
To overcome the limitations of the clinical use of neurotrophins nerve growth factor (NGF) and brain-derived neurotrophic factor (BDNF), scientists have been trying to create their low-molecular-weight mimetics having improved pharmacokinetic properties and lacking side effects of full-sized proteins since the 90s of the last century. The efforts of various research groups have led to the production of peptide and nonpeptide mimetics, being agonists or modulators of the corresponding Trk or p75 receptors that reproduced the therapeutic effects of full-sized proteins. This review discusses different strategies and approaches to the design of such compounds. The relationship between the structure of the mimetics obtained and their action mechanisms and pharmacological properties are analyzed. Special attention is paid to the dipeptide mimetics of individual NGF and BDNF loops having different patterns of activation of Trk receptors signal transduction pathways, phosphoinositide 3-kinase/protein kinase B and mitogen-activated protein kinase/extracellular signal-regulated kinase, which allowed to evaluate the contribution of each pathway to different pharmacological effects. In conclusion, data on therapeutically promising compounds being at different stages of preclinical and clinical studies are summarized.
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Affiliation(s)
- Tatiana A Gudasheva
- Medicinal Chemistry Department, V. V. Zakusov Research Institute of Pharmacology, Moscow, Russian Federation
| | - Polina Y Povarnina
- Medicinal Chemistry Department, V. V. Zakusov Research Institute of Pharmacology, Moscow, Russian Federation
| | - Aleksey V Tarasiuk
- Medicinal Chemistry Department, V. V. Zakusov Research Institute of Pharmacology, Moscow, Russian Federation
| | - Sergey B Seredenin
- Department of Pharmacogenetics, V. V. Zakusov Research Institute of Pharmacology, Moscow, Russian Federation
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Nguyen LD, Fischer TT, Abreu D, Arroyo A, Urano F, Ehrlich BE. Calpain inhibitor and ibudilast rescue β cell functions in a cellular model of Wolfram syndrome. Proc Natl Acad Sci U S A 2020; 117:17389-17398. [PMID: 32632005 PMCID: PMC7382278 DOI: 10.1073/pnas.2007136117] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Wolfram syndrome is a rare multisystem disease characterized by childhood-onset diabetes mellitus and progressive neurodegeneration. Most cases are attributed to pathogenic variants in a single gene, Wolfram syndrome 1 (WFS1). There currently is no disease-modifying treatment for Wolfram syndrome, as the molecular consequences of the loss of WFS1 remain elusive. Because diabetes mellitus is the first diagnosed symptom of Wolfram syndrome, we aimed to further examine the functions of WFS1 in pancreatic β cells in the context of hyperglycemia. Knockout (KO) of WFS1 in rat insulinoma (INS1) cells impaired calcium homeostasis and protein kinase B/Akt signaling and, subsequently, decreased cell viability and glucose-stimulated insulin secretion. Targeting calcium homeostasis with reexpression of WFS1, overexpression of WFS1's interacting partner neuronal calcium sensor-1 (NCS1), or treatment with calpain inhibitor and ibudilast reversed deficits observed in WFS1-KO cells. Collectively, our findings provide insight into the disease mechanism of Wolfram syndrome and highlight new targets and drug candidates to facilitate the development of a treatment for this disorder and similar diseases.
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Affiliation(s)
- Lien D Nguyen
- Department of Pharmacology, Yale University, New Haven, CT 06520
- Interdepartmental Neuroscience Program, Yale University, New Haven, CT 06520
| | - Tom T Fischer
- Department of Pharmacology, Yale University, New Haven, CT 06520
- Institute of Pharmacology, University of Heidelberg, 69117 Heidelberg, Germany
| | - Damien Abreu
- Department of Medicine, Division of Endocrinology, Metabolism, and Lipid Research, Washington University School of Medicine, St. Louis, MO 63110
- Medical Scientist Training Program, Washington University School of Medicine, St. Louis, MO 63110
| | - Alfredo Arroyo
- Department of Pharmacology, Yale University, New Haven, CT 06520
| | - Fumihiko Urano
- Department of Medicine, Division of Endocrinology, Metabolism, and Lipid Research, Washington University School of Medicine, St. Louis, MO 63110
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO 63110
| | - Barbara E Ehrlich
- Department of Pharmacology, Yale University, New Haven, CT 06520;
- Interdepartmental Neuroscience Program, Yale University, New Haven, CT 06520
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AKT1 Regulates Endoplasmic Reticulum Stress and Mediates the Adaptive Response of Pancreatic β Cells. Mol Cell Biol 2020; 40:MCB.00031-20. [PMID: 32179553 DOI: 10.1128/mcb.00031-20] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2020] [Accepted: 03/12/2020] [Indexed: 12/31/2022] Open
Abstract
Isoforms of protein kinase B (also known as AKT) play important roles in mediating insulin and growth factor signals. Previous studies have suggested that the AKT2 isoform is critical for insulin-regulated glucose metabolism, while the role of the AKT1 isoform remains less clear. This study focuses on the effects of AKT1 on the adaptive response of pancreatic β cells. Using a mouse model with inducible β-cell-specific deletion of the Akt1 gene (βA1KO mice), we showed that AKT1 is involved in high-fat-diet (HFD)-induced growth and survival of β cells but is unnecessary for them to maintain a population in the absence of metabolic stress. When unchallenged, βA1KO mice presented the same metabolic profile and β-cell phenotype as the control mice with an intact Akt1 gene. When metabolic stress was induced by HFD, β cells in control mice with intact Akt1 proliferated as a compensatory mechanism for metabolic overload. Similar effects were not observed in βA1KO mice. We further demonstrated that AKT1 protein deficiency caused endoplasmic reticulum (ER) stress and potentiated β cells to undergo apoptosis. Our results revealed that AKT1 protein loss led to the induction of eukaryotic initiation factor 2 α subunit (eIF2α) signaling and ER stress markers under normal-chow-fed conditions, indicating chronic low-level ER stress. Together, these data established a role for AKT1 as a growth and survival factor for adaptive β-cell response and suggest that ER stress induction is responsible for this effect of AKT1.
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Rachdaoui N. Insulin: The Friend and the Foe in the Development of Type 2 Diabetes Mellitus. Int J Mol Sci 2020; 21:ijms21051770. [PMID: 32150819 PMCID: PMC7084909 DOI: 10.3390/ijms21051770] [Citation(s) in RCA: 74] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2020] [Revised: 02/29/2020] [Accepted: 03/02/2020] [Indexed: 12/14/2022] Open
Abstract
Insulin, a hormone produced by pancreatic β-cells, has a primary function of maintaining glucose homeostasis. Deficiencies in β-cell insulin secretion result in the development of type 1 and type 2 diabetes, metabolic disorders characterized by high levels of blood glucose. Type 2 diabetes mellitus (T2DM) is characterized by the presence of peripheral insulin resistance in tissues such as skeletal muscle, adipose tissue and liver and develops when β-cells fail to compensate for the peripheral insulin resistance. Insulin resistance triggers a rise in insulin demand and leads to β-cell compensation by increasing both β-cell mass and insulin secretion and leads to the development of hyperinsulinemia. In a vicious cycle, hyperinsulinemia exacerbates the metabolic dysregulations that lead to β-cell failure and the development of T2DM. Insulin and IGF-1 signaling pathways play critical roles in maintaining the differentiated phenotype of β-cells. The autocrine actions of secreted insulin on β-cells is still controversial; work by us and others has shown positive and negative actions by insulin on β-cells. We discuss findings that support the concept of an autocrine action of secreted insulin on β-cells. The hypothesis of whether, during the development of T2DM, secreted insulin initially acts as a friend and contributes to β-cell compensation and then, at a later stage, becomes a foe and contributes to β-cell decompensation will be discussed.
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Affiliation(s)
- Nadia Rachdaoui
- Department of Animal Sciences, Room 108, Foran Hall, Rutgers, the State University of New Jersey, 59 Dudley Rd, New Brunswick, NJ 08901, USA
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Jara MA, Werneck-De-Castro JP, Lubaczeuski C, Johnson JD, Bernal-Mizrachi E. Pancreatic and duodenal homeobox-1 (PDX1) contributes to β-cell mass expansion and proliferation induced by Akt/PKB pathway. Islets 2020; 12:32-40. [PMID: 32876522 PMCID: PMC7527019 DOI: 10.1080/19382014.2020.1762471] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Maintenance of pancreatic β-cell mass and function is fundamental to glucose homeostasis and to prevent diabetes. The PI3 K-Akt-mTORC1 pathway is critical for β-cells mass and function, while PDX1 has been implicated in β-cell development, maturation, and function. Here we tested whether Akt signaling requires PDX1 expression to regulate β-cell mass, proliferation, and glucose homeostasis. In order to address that, we crossed a mouse model overexpressing constitutively active Akt mutant in β-cells (β-caAkt) with mice lacking one allele of PDX1gene (β-caAkt/pdx1+/-). While the β-caAkt mice exhibit higher plasma insulin levels, greater β-cell mass and improved glucose tolerance compared to control mice, the β-caAkt/pdx1+/- mice are hyperglycemic and intolerant to glucose. The changes in glucose homeostasis in β-caAkt/pdx1+/- were associated with a 60% reduction in β-cell mass compared to β-caAkt mice. The impaired β-cell mass in the β-caAkt/pdx1+/- mice can be explained by a lesser β-cell proliferation measured by the number of Ki67 positive β-cells. We did not observe any differences in apoptosis between β-caAkt/pdx1+/- and β-caAkt mice. In conclusion, PDX1 contributes to β-cell mass expansion and glucose metabolism induced by activation of Akt signaling.
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Affiliation(s)
- Mark Anthony Jara
- Department of Internal Medicine, Division of Endocrinology, Diabetes and Metabolism, Miller School of Medicine, University of Miami, Miami, FL, USA
| | - Joao Pedro Werneck-De-Castro
- Department of Internal Medicine, Division of Endocrinology, Diabetes and Metabolism, Miller School of Medicine, University of Miami, Miami, FL, USA
- Miami VA Health Care System, Miami, FL, USA
| | - Camila Lubaczeuski
- Department of Internal Medicine, Division of Endocrinology, Diabetes and Metabolism, Miller School of Medicine, University of Miami, Miami, FL, USA
| | - James D. Johnson
- Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, Canada
| | - Ernesto Bernal-Mizrachi
- Department of Internal Medicine, Division of Endocrinology, Diabetes and Metabolism, Miller School of Medicine, University of Miami, Miami, FL, USA
- Miami VA Health Care System, Miami, FL, USA
- CONTACT Ernesto Bernal-Mizrachi Department Of Internal Medicine, Division Of Endocrinology, Diabetes and Metabolism, University of Miami Miller School of Medicine, Miami, FL33136, USA
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31
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Oakie A, Zhou L, Rivers S, Cheung C, Li J, Wang R. Postnatal knockout of beta cell insulin receptor impaired insulin secretion in male mice exposed to high-fat diet stress. Mol Cell Endocrinol 2020; 499:110588. [PMID: 31541682 DOI: 10.1016/j.mce.2019.110588] [Citation(s) in RCA: 6] [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: 06/20/2019] [Revised: 08/28/2019] [Accepted: 09/16/2019] [Indexed: 01/19/2023]
Abstract
The presence of insulin receptor (IR) on insulin-secreting beta cells suggests an autocrine regulatory role for insulin in its own signalling. Congenital beta cell-specific IR knockout (βIRKO) mouse studies have demonstrated the development of age-dependent glucose intolerance. We investigated the role of beta cell IR signalling specifically during postnatal life following undisturbed prenatal pancreatic development and maturation. We utilized a tamoxifen-inducible mouse insulin 1 promoter (MIP) driven Cre recombinase IR knockout mouse model (MIP-βIRKO) to achieve partial knockout of IR in islets and determine the functional role of beta cell IR in adult mice fed a control normal diet (ND) or 60% high-fat diet (HFD). At 24 weeks of age, MIP-βIRKO ND mice maintained glucose tolerance, insulin release, and unchanged beta cell mass when compared to control ND mice. In contrast, 24-week-old MIP-βIRKO mice demonstrated significant glucose intolerance and lower insulin release after 18 weeks of HFD feeding. A reduction in beta cell soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) protein expression, phosphorylated AktS473 and P70S6K1T389, and glucose transporter 2 (GLUT2) expression were also identified in MIP-βIRKO HFD islets. Overall, the postnatal knockout of beta cell IR in HFD-fed mice resulted in decreased expression of beta cell glucose-sensing and exocytotic proteins and a reduction in intracellular signalling. These findings highlight that IR expression in the adult islet is required to maintain beta cell function under hyperglycemic stress.
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Affiliation(s)
- Amanda Oakie
- Children's Health Research Institute, University of Western Ontario, London, ON, N6C 2V5, Canada; Department of Pathology and Laboratory Medicine, University of Western Ontario, London, ON, N6C 2V5, Canada
| | - Liangyi Zhou
- Children's Health Research Institute, University of Western Ontario, London, ON, N6C 2V5, Canada; Department of Pathology and Laboratory Medicine, University of Western Ontario, London, ON, N6C 2V5, Canada
| | - Sydney Rivers
- Children's Health Research Institute, University of Western Ontario, London, ON, N6C 2V5, Canada; Department of Physiology and Pharmacology, and University of Western Ontario, London, ON, N6C 2V5, Canada
| | - Christy Cheung
- Children's Health Research Institute, University of Western Ontario, London, ON, N6C 2V5, Canada; Department of Physiology and Pharmacology, and University of Western Ontario, London, ON, N6C 2V5, Canada
| | - Jinming Li
- Children's Health Research Institute, University of Western Ontario, London, ON, N6C 2V5, Canada; Department of Physiology and Pharmacology, and University of Western Ontario, London, ON, N6C 2V5, Canada
| | - Rennian Wang
- Children's Health Research Institute, University of Western Ontario, London, ON, N6C 2V5, Canada; Department of Physiology and Pharmacology, and University of Western Ontario, London, ON, N6C 2V5, Canada; Department of Medicine, University of Western Ontario, London, ON, N6C 2V5, Canada.
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32
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Design, synthesis and biological evaluation of vincamine derivatives as potential pancreatic β-cells protective agents for the treatment of type 2 diabetes mellitus. Eur J Med Chem 2019; 188:111976. [PMID: 31918073 DOI: 10.1016/j.ejmech.2019.111976] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2019] [Revised: 11/06/2019] [Accepted: 12/16/2019] [Indexed: 12/19/2022]
Abstract
A series of vincamine derivatives were designed, synthesized and evaluated as pancreatic β-cells protective agents for type 2 diabetes mellitus. Most of the compounds displayed potent pancreatic β-cells protective activities and five derivatives were found to exhibit 20-50-fold higher activities than vincamine. Especially for compounds Vin-C01 and Vin-F03, exhibited a remarkable EC50 value of 0.22 μM and 0.27 μM, respectively. Their pancreatic β-cells protective activities increased approximately 2 times than vincamine. In cell viability assay, compounds Vin-C01 and Vin-F03 could effectively promote β-cell survival and protect β-cells from STZ-induced apoptosis. Further cellular mechanism of action studies demonstrated that their potent β-cells protective activities were achieved by regulating IRS2/PI3K/Akt signaling pathway. The present study evidently showed that compounds Vin-C01 and Vin-F03 were two more potent pancreatic β-cells protective agents compared to vincamine and might serve as promising lead candidates for the treatment of type 2 diabetes mellitus.
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33
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Sung Y, Jeong J, Kang RJ, Choi M, Park S, Kwon W, Lee J, Jang S, Park SJ, Kim S, Yi J, Choi S, Lee M, Liu K, Dong Z, Ryoo ZY, Kim MO. Lin28a expression protects against streptozotocin‐induced β‐cell destruction and prevents diabetes in mice. Cell Biochem Funct 2019; 37:139-147. [DOI: 10.1002/cbf.3376] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2018] [Revised: 12/02/2018] [Accepted: 01/03/2019] [Indexed: 02/06/2023]
Affiliation(s)
- Yonghun Sung
- School of Life Sciences, BK21 Plus KNU Creative BioResearch GroupKyungpook National University Daegu Republic of Korea
| | - Jain Jeong
- School of Life Sciences, BK21 Plus KNU Creative BioResearch GroupKyungpook National University Daegu Republic of Korea
- Core Protein Resources Center, DGIST Daegu Republic of Korea
| | - Ri jin Kang
- Department of Food Science and NutritionKyungpook National University Sangju Republic of Korea
| | - Minjee Choi
- School of Life Sciences, BK21 Plus KNU Creative BioResearch GroupKyungpook National University Daegu Republic of Korea
| | - Song Park
- School of Life Sciences, BK21 Plus KNU Creative BioResearch GroupKyungpook National University Daegu Republic of Korea
- Core Protein Resources Center, DGIST Daegu Republic of Korea
| | - Wookbong Kwon
- School of Life Sciences, BK21 Plus KNU Creative BioResearch GroupKyungpook National University Daegu Republic of Korea
| | - Jinhee Lee
- School of Life Sciences, BK21 Plus KNU Creative BioResearch GroupKyungpook National University Daegu Republic of Korea
| | - Soyoung Jang
- School of Life Sciences, BK21 Plus KNU Creative BioResearch GroupKyungpook National University Daegu Republic of Korea
| | - Si Jun Park
- School of Life Sciences, BK21 Plus KNU Creative BioResearch GroupKyungpook National University Daegu Republic of Korea
| | - Sung‐Hyun Kim
- School of Life Sciences, BK21 Plus KNU Creative BioResearch GroupKyungpook National University Daegu Republic of Korea
- China‐US (Henan) Hormel Cancer Institute, No.127 Dongming Road Zhengzhou China
| | - Junkoo Yi
- Gyeongsangbukdo Livestock Research Institute Yeongju Republic of Korea
| | | | - Mee‐Hyun Lee
- China‐US (Henan) Hormel Cancer Institute, No.127 Dongming Road Zhengzhou China
| | - Kangdong Liu
- China‐US (Henan) Hormel Cancer Institute, No.127 Dongming Road Zhengzhou China
| | - Zigang Dong
- China‐US (Henan) Hormel Cancer Institute, No.127 Dongming Road Zhengzhou China
| | - Zae Young Ryoo
- School of Life Sciences, BK21 Plus KNU Creative BioResearch GroupKyungpook National University Daegu Republic of Korea
| | - Myoung Ok Kim
- Department of Food Science and NutritionKyungpook National University Sangju Republic of Korea
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IPP-1 controls Akt/CREB phosphorylation extension in A 2a adenosine receptor signaling cascade in MIN6 pancreatic β-cell line. Eur J Pharmacol 2019; 850:88-96. [PMID: 30772395 DOI: 10.1016/j.ejphar.2019.02.017] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2018] [Revised: 02/12/2019] [Accepted: 02/13/2019] [Indexed: 11/23/2022]
Abstract
Signaling through A2a adenosine receptor specifically prevent pancreatic β-cells (PBCs) loses under diabetogenic conditions. However, signaling mediators of this receptor in PBCs remained unidentified. Thus, we aimed to investigate the possible involvement of PKA/Akt/IPP-1/CREB pathway in MIN6 β-cells. In addition, we investigated IPP-1 role in A2a receptor signaling pathway. The expression of A2a receptor in MIN6 cell line was evaluated by RT-PCR and its functionality confirmed by quantification of cAMP in response to the CGS 21680, an A2a receptor agonist. MTT and Brdu assays were used to evaluate cell viability and proliferation, respectively. PKA activity and insulin release were evaluated using ELISA methods. P-Akt/Akt, p-IPP-1/IPP-1, and p-CREB/CREB levels were assessed using western blotting. IPP-1 knock down assessments was performed using specific siRNA. Our result revealed that MIN6 cells express A2a receptor which actively increased cAMP levels (with EC50 = 2.41 µM) and PKA activity. Activation of this receptor increased cell viability, proliferation and insulin release. Moreover, we mentioned A2a receptor stimulation increased p-Akt, p-IPP-1, and p-CREB levels in dose (max at 10 µM of CGS 21680) and time (max at 30 min after CGS 21680 treatment) dependent manner. Interestingly, herein, we found in IPP-1 knocked down cells, A2a receptor failed to activate Akt and CREB. Altogether, we mentioned that in MIN6 cells A2a receptor increase cell viability, proliferation and insulin release through PKA/Akt/IPP-1/CREB signaling pathway. In addition, we conclude A2a receptor signaling through this pathway is dependent to activation of IPP-1.
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35
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Du T, Yang L, Xu X, Shi X, Xu X, Lu J, Lv J, Huang X, Chen J, Wang H, Ye J, Hu L, Shen X. Vincamine as a GPR40 agonist improves glucose homeostasis in type 2 diabetic mice. J Endocrinol 2019; 240:195-214. [PMID: 30400036 DOI: 10.1530/joe-18-0432] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/15/2018] [Accepted: 11/02/2018] [Indexed: 12/18/2022]
Abstract
Vincamine, a monoterpenoid indole alkaloid extracted from the Madagascar periwinkle, is clinically used for the treatment of cardio-cerebrovascular diseases, while also treated as a dietary supplement with nootropic function. Given the neuronal protection of vincamine and the potency of β-cell amelioration in treating type 2 diabetes mellitus (T2DM), we investigated the potential of vincamine in protecting β-cells and ameliorating glucose homeostasis in vitro and in vivo. Interestingly, we found that vincamine could protect INS-832/13 cells function by regulating G-protein-coupled receptor 40 (GPR40)/cAMP/Ca2+/IRS2/PI3K/Akt signaling pathway, while increasing glucose-stimulated insulin secretion (GSIS) by modulating GPR40/cAMP/Ca2+/CaMKII pathway, which reveals a novel mechanism underlying GPR40-mediated cell protection and GSIS in INS-832/13 cells. Moreover, administration of vincamine effectively ameliorated glucose homeostasis in either HFD/STZ or db/db type 2 diabetic mice. To our knowledge, our current work might be the first report on vincamine targeting GPR40 and its potential in the treatment of T2DM.
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MESH Headings
- Animals
- Blood Glucose/metabolism
- Cell Line, Tumor
- Cell Proliferation/drug effects
- Diabetes Mellitus, Experimental/genetics
- Diabetes Mellitus, Experimental/metabolism
- Diabetes Mellitus, Experimental/prevention & control
- Diabetes Mellitus, Type 2/genetics
- Diabetes Mellitus, Type 2/metabolism
- Diabetes Mellitus, Type 2/prevention & control
- Glucose/metabolism
- Homeostasis/drug effects
- Insulin Secretion/drug effects
- Insulin-Secreting Cells/drug effects
- Insulin-Secreting Cells/metabolism
- Male
- Mice
- Receptors, G-Protein-Coupled/agonists
- Receptors, G-Protein-Coupled/genetics
- Receptors, G-Protein-Coupled/metabolism
- Signal Transduction/drug effects
- Vasodilator Agents/pharmacology
- Vincamine/pharmacology
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Affiliation(s)
- Te Du
- Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
- School of Pharmacy, University of Chinese Academy of Sciences, Beijing, China
| | - Liu Yang
- Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
- School of Pharmacy, University of Chinese Academy of Sciences, Beijing, China
| | - Xu Xu
- School of Medicine and Life Sciences, Nanjing University of Chinese Medicine, Nanjing, China
| | - Xiaofan Shi
- Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
- School of Pharmacy, University of Chinese Academy of Sciences, Beijing, China
| | - Xin Xu
- Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
- School of Pharmacy, University of Chinese Academy of Sciences, Beijing, China
| | - Jian Lu
- School of Medicine and Life Sciences, Nanjing University of Chinese Medicine, Nanjing, China
| | - Jianlu Lv
- School of Medicine and Life Sciences, Nanjing University of Chinese Medicine, Nanjing, China
| | - Xi Huang
- School of Medicine and Life Sciences, Nanjing University of Chinese Medicine, Nanjing, China
| | - Jing Chen
- Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
- School of Pharmacy, University of Chinese Academy of Sciences, Beijing, China
| | - Heyao Wang
- Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
- School of Pharmacy, University of Chinese Academy of Sciences, Beijing, China
| | - Jiming Ye
- School of Health and Biomedical Sciences, RMIT University, Victoria, Australia
| | - Lihong Hu
- School of Medicine and Life Sciences, Nanjing University of Chinese Medicine, Nanjing, China
| | - Xu Shen
- Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
- School of Pharmacy, University of Chinese Academy of Sciences, Beijing, China
- School of Medicine and Life Sciences, Nanjing University of Chinese Medicine, Nanjing, China
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36
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Li J, Wang Z, Ren L, Fan L, Liu W, Jiang Y, Lau HK, Liu R, Wang Q. Antagonistic interaction between Nodal and insulin modulates pancreatic β-cell proliferation and survival. Cell Commun Signal 2018; 16:79. [PMID: 30409165 PMCID: PMC6225724 DOI: 10.1186/s12964-018-0288-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2018] [Accepted: 10/25/2018] [Indexed: 12/21/2022] Open
Abstract
Background Insulin signaling pathway in β-cell is essential to promote β-cells proliferation and survival, while Nodal–ALK7–Smad3 signaling involves β-cells apoptosis. We attempted to address inter-relationship between Nodal and insulin in modulating β-cell proliferation and apoptosis. Methods Using INS-1 β-cells and isolated rat islets, we examined the effects of Nodal, insulin, or the two combined on β-cell proliferation and/or apoptosis. Results The β-cells under high-glucose or palmitate conditions showed significant up-regulation of Nodal expression and activation of its downstream signaling pathway resulted in increased cleaved caspase-3. Insulin treatment led to significantly attenuated Nodal-induced cell apoptotic pathway. Similar results were found in directly Nodal-treated β-cell that insulin could partially block Nodal-induced up-regulation of ALK7–Smad3–caspase-3 signaling pathways with significantly attenuated β-cell apoptosis. Interestingly, we found that insulin-induced Akt activation and downstream molecules including GSK-3β, β-catenin and ERK1/2 was significantly attenuated by the co-treatment with Nodal, resulted in decreased cell proliferation. Furthermore, Nodal decreased glucose-evoked calcium influx and played a negative role during glucose-stimulated insulin secretion in the β-cells. Immunocytochemistry studies showed that Nodal treatment translocated Smad3 from cytosol mostly to the nucleus; however, co-treatment with insulin significantly decreased Smad3 nuclear localization. Co-immunoprecipitation experiments showed a directly interaction between Smad3 and Akt, and this interaction was enhanced by co-treatment with insulin. Conclusions Our data suggest that the antagonistic interaction between Nodal and insulin has a role in the regulation of β-cell mass and secretion. Electronic supplementary material The online version of this article (10.1186/s12964-018-0288-0) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Junfeng Li
- Department of Endocrinology and Metabolism, Huashan Hospital, Fudan University, Shanghai, China.,Department of Endocrinology, Renmin Hospital of Wuhan University, Wuhan, China
| | - Zhihong Wang
- Department of Endocrinology and Metabolism, Huashan Hospital, Fudan University, Shanghai, China
| | - Liwei Ren
- Department of Endocrinology and Metabolism, Huashan Hospital, Fudan University, Shanghai, China
| | - Linling Fan
- Department of Endocrinology and Metabolism, Huashan Hospital, Fudan University, Shanghai, China
| | - Wenjuan Liu
- Department of Endocrinology and Metabolism, Huashan Hospital, Fudan University, Shanghai, China
| | - Yaojing Jiang
- Department of Endocrinology and Metabolism, Huashan Hospital, Fudan University, Shanghai, China
| | - Harry K Lau
- Division of Endocrinology and Metabolism, Keenan Research Centre for Biomedical Science of St. Michael's Hospital, Toronto, Ontario, Canada.,Department of Physiology and Medicine, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Rui Liu
- Department of Endocrinology and Metabolism, Huashan Hospital, Fudan University, Shanghai, China
| | - Qinghua Wang
- Department of Endocrinology and Metabolism, Huashan Hospital, Fudan University, Shanghai, China. .,Division of Endocrinology and Metabolism, Keenan Research Centre for Biomedical Science of St. Michael's Hospital, Toronto, Ontario, Canada. .,Department of Physiology and Medicine, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada.
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37
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Rachdaoui N, Polo-Parada L, Ismail-Beigi F. Prolonged Exposure to Insulin Inactivates Akt and Erk 1/2 and Increases Pancreatic Islet and INS1E β-Cell Apoptosis. J Endocr Soc 2018; 3:69-90. [PMID: 30697602 PMCID: PMC6344346 DOI: 10.1210/js.2018-00140] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/09/2018] [Accepted: 10/29/2018] [Indexed: 12/18/2022] Open
Abstract
Chronic hyperinsulinemia, in vivo, increases the resistance of peripheral tissues to insulin by desensitizing insulin signaling. Insulin, in a heterologous manner, can also cause IGF-1 resistance. The aim of the current study was to investigate whether insulin-mediated insulin and IGF-1 resistance develops in pancreatic β-cells and whether this resistance results in β-cell decompensation. Chronic exposure of rat islets or INS1E β-cells to increasing concentrations of insulin decreased AktS473 phosphorylation in response to subsequent acute stimulation with 10 nM insulin or IGF-1. Prolonged exposure to high insulin levels not only inhibited AktS473 phosphorylation, but it also resulted in a significant inhibition of the phosphorylation of P70S6 kinase and Erk1/2 phosphorylation in response to the acute stimulation by glucose, insulin, or IGF-1. Decreased activation of Akt, P70S6K, and Erk1/2 was associated with decreased insulin receptor substrate 2 tyrosine phosphorylation and insulin receptor β-subunit abundance; neither IGF receptor β-subunit content nor its phosphorylation were affected. These signaling impairments were associated with decreased SERCA2 expression, perturbed plasma membrane calcium current and intracellular calcium handling, increased endoplasmic reticulum stress markers such as eIF2αS51 phosphorylation and Bip (GRP78) expression, and increased islet and β-cell apoptosis. We demonstrate that prolonged exposure to high insulin levels induces not only insulin resistance, but in a heterologous manner causes resistance to IGF-1 in rat islets and insulinoma cells resulting in decreased cell survival. These findings suggest the possibility that chronic exposure to hyperinsulinemia may negatively affect β-cell mass by increasing β-cell apoptosis.
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Affiliation(s)
- Nadia Rachdaoui
- Division of Clinical and Molecular Endocrinology, Department of Medicine, Case Western Reserve University, Cleveland, Ohio
| | - Luis Polo-Parada
- Department of Medical Pharmacology and Physiology, Dalton Cardiovascular Research Center, University of Missouri-Columbia, Columbia, Missouri
| | - Faramarz Ismail-Beigi
- Division of Clinical and Molecular Endocrinology, Department of Medicine, Case Western Reserve University, Cleveland, Ohio
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Paschen M, Moede T, Valladolid-Acebes I, Leibiger B, Moruzzi N, Jacob S, García-Prieto CF, Brismar K, Leibiger IB, Berggren PO. Diet-induced β-cell insulin resistance results in reversible loss of functional β-cell mass. FASEB J 2018; 33:204-218. [PMID: 29957055 PMCID: PMC6355083 DOI: 10.1096/fj.201800826r] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Although convincing in genetic models, the relevance of β-cell insulin resistance in diet-induced type 2 diabetes (T2DM) remains unclear. Exemplified by diabetes-prone, male, C57B1/6J mice being fed different combinations of Western-style diet, we show that β-cell insulin resistance occurs early during T2DM progression and is due to a combination of lipotoxicity and increased β-cell workload. Within 8 wk of being fed a high-fat, high-sucrose diet, mice became obese, developed impaired insulin and glucose tolerances, and displayed noncompensatory insulin release, due, at least in part, to reduced expression of syntaxin-1A. Through reporter islets transplanted to the anterior chamber of the eye, we demonstrated a concomitant loss of functional β-cell mass. When mice were changed from diabetogenic diet to normal chow diet, the diabetes phenotype was reversed, suggesting a remarkable plasticity of functional β-cell mass in the early phase of T2DM development. Our data reinforce the relevance of diet composition as an environmental factor determining different routes of diabetes progression in a given genetic background. Employing the in vivo reporter islet–monitoring approach will allow researchers to define key times in the dynamics of reversible loss of functional β-cell mass and, thus, to investigate the underlying, molecular mechanisms involved in the progression toward T2DM manifestation.—Paschen, M., Moede, T., Valladolid-Acebes, I., Leibiger, B., Moruzzi, N., Jacob, S., García-Prieto, C. F., Brismar, K., Leibiger, I. B., Berggren, P.-O. Diet-induced β-cell insulin resistance results in reversible loss of functional β-cell mass.
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Affiliation(s)
- Meike Paschen
- The Rolf Luft Research Center for Diabetes and Endocrinology, Karolinska Institutet, Stockholm, Sweden
| | - Tilo Moede
- The Rolf Luft Research Center for Diabetes and Endocrinology, Karolinska Institutet, Stockholm, Sweden
| | - Ismael Valladolid-Acebes
- The Rolf Luft Research Center for Diabetes and Endocrinology, Karolinska Institutet, Stockholm, Sweden
| | - Barbara Leibiger
- The Rolf Luft Research Center for Diabetes and Endocrinology, Karolinska Institutet, Stockholm, Sweden
| | - Noah Moruzzi
- The Rolf Luft Research Center for Diabetes and Endocrinology, Karolinska Institutet, Stockholm, Sweden
| | - Stefan Jacob
- The Rolf Luft Research Center for Diabetes and Endocrinology, Karolinska Institutet, Stockholm, Sweden
| | - Concha F García-Prieto
- The Rolf Luft Research Center for Diabetes and Endocrinology, Karolinska Institutet, Stockholm, Sweden
| | - Kerstin Brismar
- The Rolf Luft Research Center for Diabetes and Endocrinology, Karolinska Institutet, Stockholm, Sweden
| | - Ingo B Leibiger
- The Rolf Luft Research Center for Diabetes and Endocrinology, Karolinska Institutet, Stockholm, Sweden
| | - Per-Olof Berggren
- The Rolf Luft Research Center for Diabetes and Endocrinology, Karolinska Institutet, Stockholm, Sweden
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39
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Zhang Y, Warnock GL, Ao Z, Park YJ, Safikhan N, Ghahary A, Marzban L. Amyloid formation reduces protein kinase B phosphorylation in primary islet β-cells which is improved by blocking IL-1β signaling. PLoS One 2018; 13:e0193184. [PMID: 29474443 PMCID: PMC5825069 DOI: 10.1371/journal.pone.0193184] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2016] [Accepted: 02/02/2018] [Indexed: 12/31/2022] Open
Abstract
Amyloid formation in the pancreatic islets due to aggregation of human islet amyloid polypeptide (hIAPP) contributes to reduced β-cell mass and function in type 2 diabetes (T2D) and islet transplantation. Protein kinase B (PKB) signaling plays a key role in the regulation of β-cell survival, function and proliferation. In this study, we used human and hIAPP-expressing transgenic mouse islets in culture as two ex vivo models of human islet amyloid formation to: 1. Investigate the effects of amyloid formation on PKB phosphorylation in primary islet β-cells; 2. Test if inhibition of amyloid formation and/or interleukin-1β (IL-1β) signaling in islets can restore the changes in β-cell phospho-PKB levels mediated by amyloid formation. Human and hIAPP-expressing mouse islets were cultured in elevated glucose with an amyloid inhibitor (Congo red) or embedded within collagen matrix to prevent amyloid formation. To block the IL-1β signaling, human islets were treated with an IL-1 receptor antagonist (anakinra) or a glucagon-like peptide-1 agonist (exenatide). β-cell phospho-PKB levels, proliferation, apoptosis, islet IL-1β levels and amyloid formation were assessed. Amyloid formation in both cultured human and hIAPP-expressing mouse islets reduced β-cell phospho-PKB levels and increased islet IL-1β levels, both of which were restored by prevention of amyloid formation either by the amyloid inhibitor or embedding islets in collagen matrix, resulting in improved β-cell survival. Furthermore, inhibition of IL-1β signaling by treatment with anakinra or exenatide increased β-cell phospho-PKB levels, enhanced proliferation and reduced apoptosis in amyloid forming human islets during 7-day culture. These data suggest that amyloid formation leads to reduced PKB phosphorylation in β-cells which is associated with elevated islet IL-1β levels. Inhibitors of amyloid or amyloid-induced IL-1β production may provide a new approach to restore phospho-PKB levels thereby enhance β-cell survival and proliferation in conditions associated with islet amyloid formation such as T2D and clinical islet transplantation.
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Affiliation(s)
- Yun Zhang
- Department of Surgery, Faculty of Medicine, University of British Columbia, Vancouver, BC, Canada
| | - Garth L. Warnock
- Department of Surgery, Faculty of Medicine, University of British Columbia, Vancouver, BC, Canada
| | - Ziliang Ao
- Department of Surgery, Faculty of Medicine, University of British Columbia, Vancouver, BC, Canada
| | - Yoo Jin Park
- Department of Surgery, Faculty of Medicine, University of British Columbia, Vancouver, BC, Canada
| | - Nooshin Safikhan
- Department of Surgery, Faculty of Medicine, University of British Columbia, Vancouver, BC, Canada
| | - Aziz Ghahary
- Department of Surgery, Faculty of Medicine, University of British Columbia, Vancouver, BC, Canada
| | - Lucy Marzban
- Department of Surgery, Faculty of Medicine, University of British Columbia, Vancouver, BC, Canada
- * E-mail:
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40
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mTORC2 Signaling: A Path for Pancreatic β Cell's Growth and Function. J Mol Biol 2018; 430:904-918. [PMID: 29481838 DOI: 10.1016/j.jmb.2018.02.013] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2017] [Revised: 02/14/2018] [Accepted: 02/14/2018] [Indexed: 12/16/2022]
Abstract
The mechanistic target of rapamycin (mTOR) signaling pathway is an evolutionary conserved pathway that senses signals from nutrients and growth factors to regulate cell growth, metabolism and survival. mTOR acts in two biochemically and functionally distinct complexes, mTOR complex 1 (mTORC1) and 2 (mTORC2), which differ in terms of regulatory mechanisms, substrate specificity and functional outputs. While mTORC1 signaling has been extensively studied in islet/β-cell biology, recent findings demonstrate a distinct role for mTORC2 in the regulation of pancreatic β-cell function and mass. mTORC2, a key component of the growth factor receptor signaling, is declined in β cells under diabetogenic conditions and in pancreatic islets from patients with type 2 diabetes. β cell-selective mTORC2 inactivation leads to glucose intolerance and acceleration of diabetes as a result of reduced β-cell mass, proliferation and impaired glucose-stimulated insulin secretion. Thereby, many mTORC2 targets, such as AKT, PKC, FOXO1, MST1 and cell cycle regulators, play an important role in β-cell survival and function. This indicates mTORC2 as important pathway for the maintenance of β-cell homeostasis, particularly to sustain proper β-cell compensatory response in the presence of nutrient overload and metabolic demand. This review summarizes recent emerging advances on the contribution of mTORC2 and its associated signaling on the regulation of glucose metabolism and functional β-cell mass under physiological and pathophysiological conditions in type 2 diabetes.
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Karandrea S, Yin H, Liang X, Heart EA. BDE-47 and BDE-85 stimulate insulin secretion in INS-1 832/13 pancreatic β-cells through the thyroid receptor and Akt. ENVIRONMENTAL TOXICOLOGY AND PHARMACOLOGY 2017; 56:29-34. [PMID: 28869857 DOI: 10.1016/j.etap.2017.08.030] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/26/2017] [Revised: 08/28/2017] [Accepted: 08/29/2017] [Indexed: 05/12/2023]
Abstract
PBDEs (polybrominated diphenyl ethers) are environmental pollutants that have been linked to the development of type 2 diabetes, however, the precise mechanisms are not clear. Particularly, their direct effect on insulin secretion is unknown. In this study, we show that two PBDE congeners, BDE-47 and BDE-85, potentiate glucose-stimulated insulin secretion (GSIS) in INS-1 832/13 cells. This effect of BDE-47 and BDE-85 on GSIS was dependent on thyroid receptor (TR). Both BDE-47 and BDE-85 (10μM) activated Akt during an acute exposure. The activation of Akt by BDE-47 and BDE-85 plays a role in their potentiation of GSIS, as pharmacological inhibition of PI3K, an upstream activator of Akt, significantly lowers GSIS compared to compounds alone. This study shows that BDE-47 and BDE-85 directly act on pancreatic β-cells to stimulate GSIS, and that this effect is mediated by the thyroid receptor (TR) and Akt activation.
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Affiliation(s)
- Shpetim Karandrea
- Department of Molecular Pharmacology and Physiology, University of South Florida, Tampa, FL, 33612, United States
| | - Huquan Yin
- Department of Molecular Pharmacology and Physiology, University of South Florida, Tampa, FL, 33612, United States
| | - Xiaomei Liang
- Department of Molecular Pharmacology and Physiology, University of South Florida, Tampa, FL, 33612, United States
| | - Emma A Heart
- Department of Molecular Pharmacology and Physiology, University of South Florida, Tampa, FL, 33612, United States.
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Nygren PJ, Mehta S, Schweppe DK, Langeberg LK, Whiting JL, Weisbrod CR, Bruce JE, Zhang J, Veesler D, Scott JD. Intrinsic disorder within AKAP79 fine-tunes anchored phosphatase activity toward substrates and drug sensitivity. eLife 2017; 6:30872. [PMID: 28967377 PMCID: PMC5653234 DOI: 10.7554/elife.30872] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2017] [Accepted: 09/28/2017] [Indexed: 12/23/2022] Open
Abstract
Scaffolding the calcium/calmodulin-dependent phosphatase 2B (PP2B, calcineurin) focuses and insulates termination of local second messenger responses. Conformational flexibility in regions of intrinsic disorder within A-kinase anchoring protein 79 (AKAP79) delineates PP2B access to phosphoproteins. Structural analysis by negative-stain electron microscopy (EM) reveals an ensemble of dormant AKAP79-PP2B configurations varying in particle length from 160 to 240 Å. A short-linear interaction motif between residues 337–343 of AKAP79 is the sole PP2B-anchoring determinant sustaining these diverse topologies. Activation with Ca2+/calmodulin engages additional interactive surfaces and condenses these conformational variants into a uniform population with mean length 178 ± 17 Å. This includes a Leu-Lys-Ile-Pro sequence (residues 125–128 of AKAP79) that occupies a binding pocket on PP2B utilized by the immunosuppressive drug cyclosporin. Live-cell imaging with fluorescent activity-sensors infers that this region fine-tunes calcium responsiveness and drug sensitivity of the anchored phosphatase. Signaling molecules such as the hormone epinephrine (also known as adrenaline) activate a range of responses inside cells. The responses often involve proteins being chemically modified to change how active they are, which in turn controls specific processes happening inside the cell. One type of modification involves certain enzymes adding or removing molecules known as phosphate groups from specific proteins. For example, an enzyme called PP2B (also known as calcineurin) is able to remove phosphate groups from a variety of proteins. PP2B plays crucial roles in many different processes in animals including immune responses, nerve cell signaling and heart activity, and is the target of several medicinal drugs that suppress the immune system. Since PP2B plays so many roles in the body, these drugs often have unintended side effects. Therefore, studying how the body regulates this enzyme may help us to understand what causes these side effects. Previous studies have shown that PP2B is activated by calcium ions, which can act as signals in many different situations inside cells. A protein called AKAP79 anchors PP2B to specific locations in the cell so that it only operates where it is needed. Some evidence suggests that calcium ions affect how AKAP79 and PP2B interact, but it is not known how this works. Nygren et al. investigated how the PP2B enzyme and AKAP79 protein interact inside human cells and in cell-free systems. The experiments showed that short regions within the AKAP79 protein are responsible for binding to PP2B. These regions and the flexible structure of the entire AKAP79 protein work together to fine-tune how PP2B responds to calcium ions. In the presence of higher levels of calcium ions, another ‘auxiliary’ region of AKAP79 also binds to PP2B. This auxiliary region binds to a site on the enzyme where an immunosuppressive drug called cyclosporine can also bind. This suggests that AKAP79 binding to PP2B may affect the sensitivity of the PP2B enzyme to cyclosporine. This study demonstrates that the activity of PP2B can be precisely controlled by interactions with proteins such as AKAP79. Further work on these interactions may help develop more effective drugs that cause fewer side effects in patients.
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Affiliation(s)
- Patrick J Nygren
- Department of Pharmacology, Howard Hughes Medical Institute, University of Washington, Seattle, United States
| | - Sohum Mehta
- Department of Pharmacology, University of California, San Diego, San Diego, United States
| | - Devin K Schweppe
- Department of Genome Sciences, University of Washington, Seattle, United States
| | - Lorene K Langeberg
- Department of Pharmacology, Howard Hughes Medical Institute, University of Washington, Seattle, United States
| | - Jennifer L Whiting
- Department of Pharmacology, Howard Hughes Medical Institute, University of Washington, Seattle, United States
| | - Chad R Weisbrod
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, United States
| | - James E Bruce
- Department of Genome Sciences, University of Washington, Seattle, United States
| | - Jin Zhang
- Department of Pharmacology, University of California, San Diego, San Diego, United States
| | - David Veesler
- Department of Biochemistry, University of Washington, Seattle, United States
| | - John D Scott
- Department of Pharmacology, Howard Hughes Medical Institute, University of Washington, Seattle, United States
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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: 5.4] [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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Freyberg Z, Aslanoglou D, Shah R, Ballon JS. Intrinsic and Antipsychotic Drug-Induced Metabolic Dysfunction in Schizophrenia. Front Neurosci 2017; 11:432. [PMID: 28804444 PMCID: PMC5532378 DOI: 10.3389/fnins.2017.00432] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2017] [Accepted: 07/13/2017] [Indexed: 12/12/2022] Open
Abstract
For decades, there have been observations demonstrating significant metabolic disturbances in people with schizophrenia including clinically relevant weight gain, hypertension, and disturbances in glucose and lipid homeostasis. Many of these findings pre-date the use of antipsychotic drugs (APDs) which on their own are also strongly associated with metabolic side effects. The combination of APD-induced metabolic changes and common adverse environmental factors associated with schizophrenia have made it difficult to determine the specific contributions of each to the overall metabolic picture. Data from drug-naïve patients, both from the pre-APD era and more recently, suggest that there may be an intrinsic metabolic risk associated with schizophrenia. Nevertheless, these findings remain controversial due to significant clinical variability in both psychiatric and metabolic symptoms throughout patients' disease courses. Here, we provide an extensive review of classic and more recent literature describing the metabolic phenotype associated with schizophrenia. We also suggest potential mechanistic links between signaling pathways associated with schizophrenia and metabolic dysfunction. We propose that, beyond its symptomatology in the central nervous system, schizophrenia is also characterized by pathophysiology in other organ systems directly related to metabolic control.
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Affiliation(s)
- Zachary Freyberg
- Department of Psychiatry, University of PittsburghPittsburgh, PA, United States
- Department of Cell Biology, University of PittsburghPittsburgh, PA, United States
| | - Despoina Aslanoglou
- Department of Psychiatry, University of PittsburghPittsburgh, PA, United States
| | - Ripal Shah
- Department of Psychiatry and Behavioral Sciences, Stanford UniversityStanford, CA, United States
| | - Jacob S. Ballon
- Department of Psychiatry and Behavioral Sciences, Stanford UniversityStanford, CA, United States
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45
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Loss of mTORC1 signalling impairs β-cell homeostasis and insulin processing. Nat Commun 2017; 8:16014. [PMID: 28699639 PMCID: PMC5510183 DOI: 10.1038/ncomms16014] [Citation(s) in RCA: 110] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2016] [Accepted: 05/22/2017] [Indexed: 12/15/2022] Open
Abstract
Deregulation of mTOR complex 1 (mTORC1) signalling increases the risk for metabolic diseases, including type 2 diabetes. Here we show that β-cell-specific loss of mTORC1 causes diabetes and β-cell failure due to defects in proliferation, autophagy, apoptosis and insulin secretion by using mice with conditional (βraKO) and inducible (MIP-βraKOf/f) raptor deletion. Through genetic reconstitution of mTORC1 downstream targets, we identify mTORC1/S6K pathway as the mechanism by which mTORC1 regulates β-cell apoptosis, size and autophagy, whereas mTORC1/4E-BP2-eIF4E pathway regulates β-cell proliferation. Restoration of both pathways partially recovers β-cell mass and hyperglycaemia. This study also demonstrates a central role of mTORC1 in controlling insulin processing by regulating cap-dependent translation of carboxypeptidase E in a 4EBP2/eIF4E-dependent manner. Rapamycin treatment decreases CPE expression and insulin secretion in mice and human islets. We suggest an important role of mTORC1 in β-cells and identify downstream pathways driving β-cell mass, function and insulin processing. Deregulation of mTORC1 pathway has been associated with several human diseases including diabetes, neurodegeneration and cancer. Here Blandino-Rosano et al. show that mTORC1 signalling controls insulin secretion and β-cell maintenance by regulation of β-cell proliferation, apoptosis and autophagy and insulin processing.
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46
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Li H, Li Y, Xiang L, Zhang J, Zhu B, Xiang L, Dong J, Liu M, Xiang G. GDF11 Attenuates Development of Type 2 Diabetes via Improvement of Islet β-Cell Function and Survival. Diabetes 2017; 66:1914-1927. [PMID: 28450417 DOI: 10.2337/db17-0086] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/19/2017] [Accepted: 04/18/2017] [Indexed: 11/13/2022]
Abstract
Growth differentiation factor 11 (GDF11) has been implicated in the regulation of islet development and a variety of aging conditions, but little is known about the physiological functions of GDF11 in adult pancreatic islets. Here, we showed that systematic replenishment of GDF11 not only preserved insulin secretion but also improved the survival and morphology of β-cells and improved glucose metabolism in both nongenetic and genetic mouse models of type 2 diabetes (T2D). Conversely, anti-GDF11 monoclonal antibody treatment caused β-cell failure and lethal T2D. In vitro treatment of isolated murine islets and MIN6 cells with recombinant GDF11 attenuated glucotoxicity-induced β-cell dysfunction and apoptosis. Mechanistically, the GDF11-mediated protective effects could be attributed to the activation of transforming growth factor-β/Smad2 and phosphatidylinositol-4,5-bisphosphate 3-kinase-AKT-FoxO1 signaling. These findings suggest that GDF11 repletion may improve β-cell function and mass and thus may lead to a new therapeutic approach for T2D.
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Affiliation(s)
- Huan Li
- Department of Endocrinology, Wuhan General Hospital of Guangzhou Command, Wuhan, Hubei Province, China
| | - Yixiang Li
- Radiation-Diagnostic/Oncology School of Medicine, Emory University, Atlanta, GA
| | - Lingwei Xiang
- Mathematics and Statistics Department, Georgia State University, Atlanta, GA
| | - JiaJia Zhang
- Department of Endocrinology, Wuhan General Hospital of Guangzhou Command, Wuhan, Hubei Province, China
| | - Biao Zhu
- Department of Endocrinology, Wuhan General Hospital of Guangzhou Command, Wuhan, Hubei Province, China
| | - Lin Xiang
- Department of Endocrinology, Wuhan General Hospital of Guangzhou Command, Wuhan, Hubei Province, China
| | - Jing Dong
- Department of Endocrinology, Wuhan General Hospital of Guangzhou Command, Wuhan, Hubei Province, China
| | - Min Liu
- Department of Endocrinology, Wuhan General Hospital of Guangzhou Command, Wuhan, Hubei Province, China
| | - Guangda Xiang
- Department of Endocrinology, Wuhan General Hospital of Guangzhou Command, Wuhan, Hubei Province, China
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47
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Nagy L, Márton J, Vida A, Kis G, Bokor É, Kun S, Gönczi M, Docsa T, Tóth A, Antal M, Gergely P, Csóka B, Pacher P, Somsák L, Bai P. Glycogen phosphorylase inhibition improves beta cell function. Br J Pharmacol 2017; 175:301-319. [PMID: 28409826 DOI: 10.1111/bph.13819] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2016] [Revised: 04/03/2017] [Accepted: 04/05/2017] [Indexed: 12/17/2022] Open
Abstract
BACKGROUND AND PURPOSE Glycogen phosphorylase (GP) is the key enzyme for glycogen degradation. GP inhibitors (GPi-s) are glucose lowering agents that cause the accumulation of glucose in the liver as glycogen. Glycogen metabolism has implications in beta cell function. Glycogen degradation can maintain cellular glucose levels, which feeds into catabolism to maintain insulin secretion, and elevated glycogen degradation levels contribute to glucotoxicity. The purpose of this study was to assess whether influencing glycogen metabolism in beta cells by GPi-s affects the function of these cells. EXPERIMENTAL APPROACH The effects of structurally different GPi-s were investigated on MIN6 insulinoma cells and in a mouse model of diabetes. KEY RESULTS GPi treatment increased glycogen content and, consequently, the surface area of glycogen in MIN6 cells. Furthermore, GPi treatment induced insulin receptor β (InsRβ), Akt and p70S6K phosphorylation, as well as pancreatic and duodenal homeobox 1(PDX1) and insulin expression. In line with these findings, GPi-s enhanced non-stimulated and glucose-stimulated insulin secretion in MIN6 cells. The InsRβ was shown to co-localize with glycogen particles as confirmed by in silico screening, where components of InsR signalling were identified as glycogen-bound proteins. GPi-s also activated the pathway of insulin secretion, indicated by enhanced glycolysis, mitochondrial oxidation and calcium signalling. Finally, GPi-s increased the size of islets of Langerhans and improved glucose-induced insulin release in mice. CONCLUSION AND IMPLICATIONS These data suggest that GPi-s also target beta cells and can be repurposed as agents to preserve beta cell function or even ameliorate beta cell dysfunction in different forms of diabetes. LINKED ARTICLES This article is part of a themed section on Inventing New Therapies Without Reinventing the Wheel: The Power of Drug Repurposing. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v175.2/issuetoc.
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Affiliation(s)
- Lilla Nagy
- Department of Medical Chemistry, Faculty of Medicine, University of Debrecen, Debrecen, Hungary.,MTA-DE Cell Biology and Signaling Research Group, Debrecen, Hungary
| | - Judit Márton
- Department of Medical Chemistry, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - András Vida
- Department of Medical Chemistry, Faculty of Medicine, University of Debrecen, Debrecen, Hungary.,MTA-DE Lendület Laboratory of Cellular Metabolism, Debrecen, Hungary
| | - Gréta Kis
- Department of Anatomy, Histology and Embryology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Éva Bokor
- Department of Organic Chemistry, Faculty of Science and Technology, University of Debrecen, Debrecen, Hungary
| | - Sándor Kun
- Department of Organic Chemistry, Faculty of Science and Technology, University of Debrecen, Debrecen, Hungary
| | - Mónika Gönczi
- Department of Physiology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Tibor Docsa
- Department of Medical Chemistry, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Attila Tóth
- Department of Cardiology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Miklós Antal
- Department of Anatomy, Histology and Embryology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary.,MTA-DE Neuroscience Research Group, Debrecen, Hungary
| | - Pál Gergely
- Department of Medical Chemistry, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Balázs Csóka
- Department of Surgery, Rutgers - New Jersey Medical School, Newark, NJ, USA.,Center for Immunity and Inflammation, Rutgers - New Jersey Medical School, Newark, NJ, USA
| | - Pal Pacher
- NIAAA, National Institutes of Health, Laboratory of Physiologic Studies, Rockville, MD, USA
| | - László Somsák
- Department of Organic Chemistry, Faculty of Science and Technology, University of Debrecen, Debrecen, Hungary
| | - Péter Bai
- Department of Medical Chemistry, Faculty of Medicine, University of Debrecen, Debrecen, Hungary.,MTA-DE Lendület Laboratory of Cellular Metabolism, Debrecen, Hungary.,Research Center for Molecular Medicine, University of Debrecen, Debrecen, Hungary
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Chau GC, Im DU, Kang TM, Bae JM, Kim W, Pyo S, Moon EY, Um SH. mTOR controls ChREBP transcriptional activity and pancreatic β cell survival under diabetic stress. J Cell Biol 2017; 216:2091-2105. [PMID: 28606928 PMCID: PMC5496625 DOI: 10.1083/jcb.201701085] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2017] [Revised: 04/05/2017] [Accepted: 05/01/2017] [Indexed: 02/06/2023] Open
Abstract
Through in vivo analyses of mTOR deficiency and in vitro studies of human and mouse pancreatic islets, Chau et al. show that mTOR plays a critical role in β cell survival in diabetes. mTOR associates with and inhibits the transcriptional ChREBP–Mlx complex, suppressing TXNIP expression and β cell death. Impaired nutrient sensing and dysregulated glucose homeostasis are common in diabetes. However, how nutrient-sensitive signaling components control glucose homeostasis and β cell survival under diabetic stress is not well understood. Here, we show that mice lacking the core nutrient-sensitive signaling component mammalian target of rapamycin (mTOR) in β cells exhibit reduced β cell mass and smaller islets. mTOR deficiency leads to a severe reduction in β cell survival and increased mitochondrial oxidative stress in chemical-induced diabetes. Mechanistically, we find that mTOR associates with the carbohydrate-response element–binding protein (ChREBP)–Max-like protein complex and inhibits its transcriptional activity, leading to decreased expression of thioredoxin-interacting protein (TXNIP), a potent inducer of β cell death and oxidative stress. Consistent with this, the levels of TXNIP and ChREBP were highly elevated in human diabetic islets and mTOR-deficient mouse islets. Thus, our results suggest that a nutrient-sensitive mTOR-regulated transcriptional network could be a novel target to improve β cell survival and glucose homeostasis in diabetes.
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Affiliation(s)
- Gia Cac Chau
- Department of Molecular Cell Biology, Samsung Biomedical Research Institute, Sungkyunkwan University School of Medicine, Suwon, Gyeonggi-do, Korea
| | - Dong Uk Im
- Department of Health Sciences and Technology, Samsung Advanced Institute for Health Sciences and Technology, Samsung Medical Center, Sungkyunkwan University, Seoul, Korea
| | - Tong Mook Kang
- Department of Physiology, Single Cell Network Research Center, Sungkyunkwan University School of Medicine, Suwon, Gyeonggi-do, Korea
| | - Jeong Mo Bae
- Department of Pathology, Seoul National University College of Medicine, Seoul National University Hospital, Seoul Metropolitan Government Boramae Medical Center, Seoul, Korea
| | - Won Kim
- Division of Gastroenterology and Hepatology, Department of Internal Medicine, Seoul National University College of Medicine, Seoul Metropolitan Government Boramae Medical Center, Seoul, Korea
| | - Suhkneung Pyo
- School of Pharmacy, Sungkyunkwan University, Suwon, Gyeonggi-do, Korea
| | - Eun-Yi Moon
- Department of Bioscience and Biotechnology, Sejong University, Seoul, Korea
| | - Sung Hee Um
- Department of Molecular Cell Biology, Samsung Biomedical Research Institute, Sungkyunkwan University School of Medicine, Suwon, Gyeonggi-do, Korea .,Department of Health Sciences and Technology, Samsung Advanced Institute for Health Sciences and Technology, Samsung Medical Center, Sungkyunkwan University, Seoul, Korea
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49
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Shirakawa J, Fernandez M, Takatani T, El Ouaamari A, Jungtrakoon P, Okawa ER, Zhang W, Yi P, Doria A, Kulkarni RN. Insulin Signaling Regulates the FoxM1/PLK1/CENP-A Pathway to Promote Adaptive Pancreatic β Cell Proliferation. Cell Metab 2017; 25:868-882.e5. [PMID: 28286049 PMCID: PMC5382039 DOI: 10.1016/j.cmet.2017.02.004] [Citation(s) in RCA: 73] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/29/2016] [Revised: 01/09/2017] [Accepted: 02/08/2017] [Indexed: 12/01/2022]
Abstract
Investigation of cell-cycle kinetics in mammalian pancreatic β cells has mostly focused on transition from the quiescent (G0) to G1 phase. Here, we report that centromere protein A (CENP-A), which is required for chromosome segregation during the M-phase, is necessary for adaptive β cell proliferation. Receptor-mediated insulin signaling promotes DNA-binding activity of FoxM1 to regulate expression of CENP-A and polo-like kinase-1 (PLK1) by modulating cyclin-dependent kinase-1/2. CENP-A deposition at the centromere is augmented by PLK1 to promote mitosis, while knocking down CENP-A limits β cell proliferation and survival. CENP-A deficiency in β cells leads to impaired adaptive proliferation in response to pregnancy, acute and chronic insulin resistance, and aging in mice. Insulin-stimulated CENP-A/PLK1 protein expression is blunted in islets from patients with type 2 diabetes. These data implicate the insulin-FoxM1/PLK1/CENP-A pathway-regulated mitotic cell-cycle progression as an essential component in the β cell adaptation to delay and/or prevent progression to diabetes.
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Affiliation(s)
- Jun Shirakawa
- Section on Islet Cell and Regenerative Biology, Joslin Diabetes Center, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Harvard Stem Cell Institute, Boston, MA 02215, USA
| | - Megan Fernandez
- Section on Islet Cell and Regenerative Biology, Joslin Diabetes Center, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Harvard Stem Cell Institute, Boston, MA 02215, USA
| | - Tomozumi Takatani
- Section on Islet Cell and Regenerative Biology, Joslin Diabetes Center, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Harvard Stem Cell Institute, Boston, MA 02215, USA
| | - Abdelfattah El Ouaamari
- Section on Islet Cell and Regenerative Biology, Joslin Diabetes Center, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Harvard Stem Cell Institute, Boston, MA 02215, USA
| | - Prapaporn Jungtrakoon
- Section on Genetics and Epidemiology, Joslin Diabetes Center and Harvard Medical School, Boston, MA 02215, USA
| | - Erin R Okawa
- Section on Islet Cell and Regenerative Biology, Joslin Diabetes Center, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Harvard Stem Cell Institute, Boston, MA 02215, USA
| | - Wei Zhang
- Section on Islet Cell and Regenerative Biology, Joslin Diabetes Center, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Harvard Stem Cell Institute, Boston, MA 02215, USA
| | - Peng Yi
- Section on Islet Cell and Regenerative Biology, Joslin Diabetes Center, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Harvard Stem Cell Institute, Boston, MA 02215, USA
| | - Alessandro Doria
- Section on Genetics and Epidemiology, Joslin Diabetes Center and Harvard Medical School, Boston, MA 02215, USA
| | - Rohit N Kulkarni
- Section on Islet Cell and Regenerative Biology, Joslin Diabetes Center, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Harvard Stem Cell Institute, Boston, MA 02215, USA.
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50
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Templeman NM, Skovsø S, Page MM, Lim GE, Johnson JD. A causal role for hyperinsulinemia in obesity. J Endocrinol 2017; 232:R173-R183. [PMID: 28052999 DOI: 10.1530/joe-16-0449] [Citation(s) in RCA: 106] [Impact Index Per Article: 15.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/16/2016] [Accepted: 01/03/2017] [Indexed: 12/13/2022]
Abstract
Insulin modulates the biochemical pathways controlling lipid uptake, lipolysis and lipogenesis at multiple levels. Elevated insulin levels are associated with obesity, and conversely, dietary and pharmacological manipulations that reduce insulin have occasionally been reported to cause weight loss. However, the causal role of insulin hypersecretion in the development of mammalian obesity remained controversial in the absence of direct loss-of-function experiments. Here, we discuss theoretical considerations around the causal role of excess insulin for obesity, as well as recent studies employing mice that are genetically incapable of the rapid and sustained hyperinsulinemia that normally accompanies a high-fat diet. We also discuss new evidence demonstrating that modest reductions in circulating insulin prevent weight gain, with sustained effects that can persist after insulin levels normalize. Importantly, evidence from long-term studies reveals that a modest reduction in circulating insulin is not associated with impaired glucose homeostasis, meaning that body weight and lipid homeostasis are actually more sensitive to small changes in circulating insulin than glucose homeostasis in these models. Collectively, the evidence from new studies on genetic loss-of-function models forces a re-evaluation of current paradigms related to obesity, insulin resistance and diabetes. The potential for translation of these findings to humans is briefly discussed.
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Affiliation(s)
- Nicole M Templeman
- Department of Cellular and Physiological SciencesDiabetes Research Group, Life Sciences Institute, University of British Columbia, Vancouver, British Columbia, Canada
| | - Søs Skovsø
- Department of Cellular and Physiological SciencesDiabetes Research Group, Life Sciences Institute, University of British Columbia, Vancouver, British Columbia, Canada
| | - Melissa M Page
- Department of Cellular and Physiological SciencesDiabetes Research Group, Life Sciences Institute, University of British Columbia, Vancouver, British Columbia, Canada
| | - Gareth E Lim
- Department of Cellular and Physiological SciencesDiabetes Research Group, Life Sciences Institute, University of British Columbia, Vancouver, British Columbia, Canada
| | - James D Johnson
- Department of Cellular and Physiological SciencesDiabetes Research Group, Life Sciences Institute, University of British Columbia, Vancouver, British Columbia, Canada
- Institute for Personalized Therapeutic NutritionVancouver, British Columbia, Canada
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