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Wang X, Kang L, Kong D, Wu X, Zhou Y, Yu G, Dai D, Ye H. A programmable protease-based protein secretion platform for therapeutic applications. Nat Chem Biol 2024; 20:432-442. [PMID: 37872400 DOI: 10.1038/s41589-023-01433-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2023] [Accepted: 09/02/2023] [Indexed: 10/25/2023]
Abstract
Cell-based therapies represent potent enabling technologies in biomedical science. However, current genetic control systems for engineered-cell therapies are predominantly based on the transcription or translation of therapeutic outputs. Here we report a protease-based rapid protein secretion system (PASS) that regulates the secretion of pretranslated proteins retained in the endoplasmic reticulum (ER) owing to an ER-retrieval signal. Upon cleavage by inducible proteases, these proteins are secreted. Three PASS variants (chemPASS, antigenPASS and optoPASS) are developed. With chemPASS, we demonstrate the reversal of hyperglycemia in diabetic mice within minutes via drug-induced insulin secretion. AntigenPASS-equipped cells recognize the tumor antigen and secrete granzyme B and perforin, inducing targeted cell apoptosis. Finally, results from mouse models of diabetes, hypertension and inflammatory pain demonstrate light-induced, optoPASS-mediated therapeutic peptide secretion within minutes, conferring anticipated therapeutic benefits. PASS is a flexible platform for rapid delivery of therapeutic proteins that can facilitate the development and adoption of cell-based precision therapies.
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Affiliation(s)
- Xinyi Wang
- Shanghai Frontiers Science Center of Genome Editing and Cell Therapy, Biomedical Synthetic Biology Research Center, Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, Shanghai, China
| | - Liping Kang
- Shanghai Frontiers Science Center of Genome Editing and Cell Therapy, Biomedical Synthetic Biology Research Center, Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, Shanghai, China
| | - Deqiang Kong
- Shanghai Frontiers Science Center of Genome Editing and Cell Therapy, Biomedical Synthetic Biology Research Center, Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, Shanghai, China
| | - Xin Wu
- Shanghai Frontiers Science Center of Genome Editing and Cell Therapy, Biomedical Synthetic Biology Research Center, Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, Shanghai, China
| | - Yang Zhou
- Shanghai Frontiers Science Center of Genome Editing and Cell Therapy, Biomedical Synthetic Biology Research Center, Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, Shanghai, China
- Wuhu Hospital, Health Science Center, East China Normal University, Wuhu City, China
| | - Guiling Yu
- Shanghai Frontiers Science Center of Genome Editing and Cell Therapy, Biomedical Synthetic Biology Research Center, Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, Shanghai, China
| | - Di Dai
- Shanghai Frontiers Science Center of Genome Editing and Cell Therapy, Biomedical Synthetic Biology Research Center, Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, Shanghai, China
| | - Haifeng Ye
- Shanghai Frontiers Science Center of Genome Editing and Cell Therapy, Biomedical Synthetic Biology Research Center, Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, Shanghai, China.
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Ellsworth PN, Herring JA, Leifer AH, Ray JD, Elison WS, Poulson PD, Crabtree JE, Van Ry PM, Tessem JS. CEBPA Overexpression Enhances β-Cell Proliferation and Survival. BIOLOGY 2024; 13:110. [PMID: 38392328 PMCID: PMC10887016 DOI: 10.3390/biology13020110] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/30/2023] [Revised: 02/08/2024] [Accepted: 02/08/2024] [Indexed: 02/24/2024]
Abstract
A commonality between type 1 and type 2 diabetes is the decline in functional β-cell mass. The transcription factor Nkx6.1 regulates β-cell development and is integral for proper β-cell function. We have previously demonstrated that Nkx6.1 depends on c-Fos mediated upregulation and the nuclear hormone receptors Nr4a1 and Nr4a3 to increase β-cell insulin secretion, survival, and replication. Here, we demonstrate that Nkx6.1 overexpression results in upregulation of the bZip transcription factor CEBPA and that CEBPA expression is independent of c-Fos regulation. In turn, CEBPA overexpression is sufficient to enhance INS-1 832/13 β-cell and primary rat islet proliferation. CEBPA overexpression also increases the survival of β-cells treated with thapsigargin. We demonstrate that increased survival in response to ER stress corresponds with changes in expression of various genes involved in the unfolded protein response, including decreased Ire1a expression. These data show that CEBPA is sufficient to enhance functional β-cell mass by increasing β-cell proliferation and modulating the unfolded protein response.
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Affiliation(s)
- Peter N Ellsworth
- Department of Nutrition, Dietetics and Food Science, Brigham Young University, Provo, UT 84602, USA
| | - Jacob A Herring
- Department of Nutrition, Dietetics and Food Science, Brigham Young University, Provo, UT 84602, USA
- Department of Microbiology and Molecular Biology, Brigham Young University, Provo, UT 84602, USA
| | - Aaron H Leifer
- Department of Nutrition, Dietetics and Food Science, Brigham Young University, Provo, UT 84602, USA
| | - Jason D Ray
- Department of Nutrition, Dietetics and Food Science, Brigham Young University, Provo, UT 84602, USA
| | - Weston S Elison
- Department of Nutrition, Dietetics and Food Science, Brigham Young University, Provo, UT 84602, USA
| | - Peter Daniel Poulson
- Department of Chemistry and Biochemistry, Brigham Young University, Provo, UT 84602, USA
| | - Jacqueline E Crabtree
- Department of Nutrition, Dietetics and Food Science, Brigham Young University, Provo, UT 84602, USA
| | - Pam M Van Ry
- Department of Chemistry and Biochemistry, Brigham Young University, Provo, UT 84602, USA
| | - Jeffery S Tessem
- Department of Nutrition, Dietetics and Food Science, Brigham Young University, Provo, UT 84602, USA
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3
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Song SE, Shin SK, Ju HY, Im SS, Song DK. Role of cytosolic and endoplasmic reticulum Ca 2+ in pancreatic beta-cells: pros and cons. Pflugers Arch 2024; 476:151-161. [PMID: 37940681 DOI: 10.1007/s00424-023-02872-2] [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: 09/04/2023] [Revised: 10/18/2023] [Accepted: 10/25/2023] [Indexed: 11/10/2023]
Abstract
Pancreatic beta cells utilize Ca2+ to secrete insulin in response to glucose. The glucose-dependent increase in cytosolic Ca2+ concentration ([Ca2+]C) activates a series of insulin secretory machinery in pancreatic beta cells. Therefore, the amount of insulin secreted in response to glucose is determined in a [Ca2+]C-dependent manner, at least within a moderate range. However, the demand for insulin secretion may surpass the capability of beta cells. Abnormal elevation of [Ca2+]C levels beyond the beta-cell endurance capacity can damage them by inducing endoplasmic reticulum (ER) stress and cell death programs such as apoptosis. Therefore, while Ca2+ is essential for the insulin secretory functions of beta cells, it could affect their survival at pathologically higher levels. Because an increase in beta-cell [Ca2+]C is inevitable under certain hazardous conditions, understanding the regulatory mechanism for [Ca2+]C is important. Therefore, this review discusses beta-cell function, survival, ER stress, and apoptosis associated with intracellular and ER Ca2+ homeostasis.
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Affiliation(s)
- Seung-Eun Song
- Department of Physiology & Obesity-Mediated Disease Research Center, Keimyung University School of Medicine, 1095 Dalgubeol-Daeroro, Dalseo-Gu, Daegu, 42601, South Korea
| | - Su-Kyung Shin
- Department of Food Science and Nutrition, Kyungpook National University, Daegu, South Korea
| | - Hyeon Yeong Ju
- Department of Physiology & Obesity-Mediated Disease Research Center, Keimyung University School of Medicine, 1095 Dalgubeol-Daeroro, Dalseo-Gu, Daegu, 42601, South Korea
| | - Seung-Soon Im
- Department of Physiology & Obesity-Mediated Disease Research Center, Keimyung University School of Medicine, 1095 Dalgubeol-Daeroro, Dalseo-Gu, Daegu, 42601, South Korea
| | - Dae-Kyu Song
- Department of Physiology & Obesity-Mediated Disease Research Center, Keimyung University School of Medicine, 1095 Dalgubeol-Daeroro, Dalseo-Gu, Daegu, 42601, South Korea.
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Mugiya T, Mothibe M, Khathi A, Ngubane P, Sibiya N. Glycaemic abnormalities induced by small molecule tryosine kinase inhibitors: a review. Front Pharmacol 2024; 15:1355171. [PMID: 38362147 PMCID: PMC10867135 DOI: 10.3389/fphar.2024.1355171] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2023] [Accepted: 01/12/2024] [Indexed: 02/17/2024] Open
Abstract
In light of the expected increase in the prevalence of diabetes mellitus due to an aging population, sedentary lifestyles, an increase in obesity, and unhealthy diets, there is a need to identify potential pharmacological agents that can heighten the risk of developing diabetes. Similarly, it is equally important to also identify those agents that show blood glucose-lowering properties. Amongst these agents are tyrosine kinase inhibitors used to treat certain types of cancers. Over the last two decades, there has been an increase in the use of targeted chemotherapy for cancers such as renal cell carcinoma, chronic leukaemia, and gastrointestinal stromal tumours. Small molecule tyrosine kinase inhibitors have been at the forefront of targeted chemotherapy. Studies have shown that small molecule tyrosine kinase inhibitors can alter glycaemic control and glucose metabolism, with some demonstrating hypoglycaemic activities whilst others showing hyperglycaemic properties. The mechanism by which small molecule tyrosine kinase inhibitors cause glycaemic dysregulation is not well understood, therefore, the clinical significance of these chemotherapeutic agents on glucose handling is also poorly documented. In this review, the effort is directed at mapping mechanistic insights into the effect of various small molecule tyrosine kinase inhibitors on glycaemic dysregulation envisaged to provide a deeper understanding of these chemotherapeutic agents on glucose metabolism. Small molecule tyrosine kinase inhibitors may elicit these observed glycaemic effects through preservation of β-cell function, improving insulin sensitivity and insulin secretion. These compounds bind to a spectrum of receptors and proteins implicated in glucose regulation for example, non-receptor tyrosine kinase SRC and ABL. Then receptor tyrosine kinase EGFR, PDGFR, and FGFR.
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Affiliation(s)
- Takudzwa Mugiya
- Pharmacology Division, Faculty of Pharmacy, Rhodes University, Makhanda, South Africa
| | - Mamosheledi Mothibe
- Pharmacology Division, Faculty of Pharmacy, Rhodes University, Makhanda, South Africa
| | - Andile Khathi
- School of Laboratory Medicine and Medical Sciences, University of KwaZulu-Natal, Durban, South Africa
| | - Phikelelani Ngubane
- School of Laboratory Medicine and Medical Sciences, University of KwaZulu-Natal, Durban, South Africa
| | - Ntethelelo Sibiya
- Pharmacology Division, Faculty of Pharmacy, Rhodes University, Makhanda, South Africa
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Di Giuseppe G, Ciccarelli G, Soldovieri L, Capece U, Cefalo CMA, Moffa S, Nista EC, Brunetti M, Cinti F, Gasbarrini A, Pontecorvi A, Giaccari A, Mezza T. First-phase insulin secretion: can its evaluation direct therapeutic approaches? Trends Endocrinol Metab 2023; 34:216-230. [PMID: 36858875 DOI: 10.1016/j.tem.2023.02.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/09/2023] [Revised: 01/26/2023] [Accepted: 02/01/2023] [Indexed: 03/03/2023]
Abstract
Our work is aimed at unraveling the role of the first-phase insulin secretion in the natural history of type 2 diabetes mellitus (T2DM) and its interrelationship with insulin resistance and with β cell function and mass. Starting from pathophysiology, we investigate the impact of impaired secretion on glucose homeostasis and explore postmeal hyperglycemia as the main clinical feature, underlining its relevance in the management of the disease. We also review dietary and pharmacological approaches aimed at improving early secretory defects and restoring residual β cell function. Furthermore, we discuss possible approaches to detect early secretory defects in clinical practice. By providing a journey through human and animal data, we attempt a unification of the recent evidence in an effort to offer a new outlook on β cell secretion.
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Affiliation(s)
- Gianfranco Di Giuseppe
- Endocrinologia e Diabetologia, Fondazione Policlinico Universitario Agostino Gemelli Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS), Rome, Italy; Dipartimento di Medicina e Chirurgia Traslazionale, Università Cattolica del Sacro Cuore, Rome, Italy.
| | - Gea Ciccarelli
- Endocrinologia e Diabetologia, Fondazione Policlinico Universitario Agostino Gemelli Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS), Rome, Italy; Dipartimento di Medicina e Chirurgia Traslazionale, Università Cattolica del Sacro Cuore, Rome, Italy
| | - Laura Soldovieri
- Endocrinologia e Diabetologia, Fondazione Policlinico Universitario Agostino Gemelli Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS), Rome, Italy; Dipartimento di Medicina e Chirurgia Traslazionale, Università Cattolica del Sacro Cuore, Rome, Italy
| | - Umberto Capece
- Endocrinologia e Diabetologia, Fondazione Policlinico Universitario Agostino Gemelli Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS), Rome, Italy; Dipartimento di Medicina e Chirurgia Traslazionale, Università Cattolica del Sacro Cuore, Rome, Italy
| | - Chiara M A Cefalo
- Department of Clinical and Molecular Medicine, University of Rome - Sapienza, Rome, Italy
| | - Simona Moffa
- Endocrinologia e Diabetologia, Fondazione Policlinico Universitario Agostino Gemelli Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS), Rome, Italy; Dipartimento di Medicina e Chirurgia Traslazionale, Università Cattolica del Sacro Cuore, Rome, Italy
| | - Enrico C Nista
- Dipartimento di Medicina e Chirurgia Traslazionale, Università Cattolica del Sacro Cuore, Rome, Italy; Digestive Disease Center, Fondazione Policlinico Universitario Agostino Gemelli IRCCS, Rome, Italy
| | - Michela Brunetti
- Endocrinologia e Diabetologia, Fondazione Policlinico Universitario Agostino Gemelli Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS), Rome, Italy; Dipartimento di Medicina e Chirurgia Traslazionale, Università Cattolica del Sacro Cuore, Rome, Italy
| | - Francesca Cinti
- Endocrinologia e Diabetologia, Fondazione Policlinico Universitario Agostino Gemelli Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS), Rome, Italy; Dipartimento di Medicina e Chirurgia Traslazionale, Università Cattolica del Sacro Cuore, Rome, Italy
| | - Antonio Gasbarrini
- Dipartimento di Medicina e Chirurgia Traslazionale, Università Cattolica del Sacro Cuore, Rome, Italy; Digestive Disease Center, Fondazione Policlinico Universitario Agostino Gemelli IRCCS, Rome, Italy
| | - Alfredo Pontecorvi
- Endocrinologia e Diabetologia, Fondazione Policlinico Universitario Agostino Gemelli Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS), Rome, Italy; Dipartimento di Medicina e Chirurgia Traslazionale, Università Cattolica del Sacro Cuore, Rome, Italy
| | - Andrea Giaccari
- Endocrinologia e Diabetologia, Fondazione Policlinico Universitario Agostino Gemelli Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS), Rome, Italy; Dipartimento di Medicina e Chirurgia Traslazionale, Università Cattolica del Sacro Cuore, Rome, Italy.
| | - Teresa Mezza
- Dipartimento di Medicina e Chirurgia Traslazionale, Università Cattolica del Sacro Cuore, Rome, Italy; Digestive Disease Center, Fondazione Policlinico Universitario Agostino Gemelli IRCCS, Rome, Italy.
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6
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Brusco N, Sebastiani G, Di Giuseppe G, Licata G, Grieco GE, Fignani D, Nigi L, Formichi C, Aiello E, Auddino S, Quero G, Cefalo CMA, Cinti F, Mari A, Ferraro PM, Pontecorvi A, Alfieri S, Giaccari A, Dotta F, Mezza T. Intra-islet insulin synthesis defects are associated with endoplasmic reticulum stress and loss of beta cell identity in human diabetes. Diabetologia 2023; 66:354-366. [PMID: 36280617 PMCID: PMC9807540 DOI: 10.1007/s00125-022-05814-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/05/2022] [Accepted: 09/07/2022] [Indexed: 01/07/2023]
Abstract
AIMS/HYPOTHESIS Endoplasmic reticulum (ER) stress and beta cell dedifferentiation both play leading roles in impaired insulin secretion in overt type 2 diabetes. Whether and how these factors are related in the natural history of the disease remains, however, unclear. METHODS In this study, we analysed pancreas biopsies from a cohort of metabolically characterised living donors to identify defects in in situ insulin synthesis and intra-islet expression of ER stress and beta cell phenotype markers. RESULTS We provide evidence that in situ altered insulin processing is closely connected to in vivo worsening of beta cell function. Further, activation of ER stress genes reflects the alteration of insulin processing in situ. Using a combination of 17 different markers, we characterised individual pancreatic islets from normal glucose tolerant, impaired glucose tolerant and type 2 diabetic participants and reconstructed disease progression. CONCLUSIONS/INTERPRETATION Our study suggests that increased beta cell workload is accompanied by a progressive increase in ER stress with defects in insulin synthesis and loss of beta cell identity.
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Affiliation(s)
- Noemi Brusco
- Diabetes and Metabolic Disease Unit, Department of Medicine, Surgery and Neurosciences, University of Siena, Siena, Italy
- Fondazione Umberto Di Mario, c/o Toscana Life Sciences, Siena, Italy
| | - Guido Sebastiani
- Diabetes and Metabolic Disease Unit, Department of Medicine, Surgery and Neurosciences, University of Siena, Siena, Italy
- Fondazione Umberto Di Mario, c/o Toscana Life Sciences, Siena, Italy
| | - Gianfranco Di Giuseppe
- Endocrinologia e Diabetologia, Fondazione Policlinico Universitario Agostino Gemelli IRCCS, Roma, Italy
- Dipartimento di Medicina e Chirurgia Traslazionale, Università Cattolica del Sacro Cuore, Roma, Italy
| | - Giada Licata
- Diabetes and Metabolic Disease Unit, Department of Medicine, Surgery and Neurosciences, University of Siena, Siena, Italy
- Fondazione Umberto Di Mario, c/o Toscana Life Sciences, Siena, Italy
| | - Giuseppina E Grieco
- Diabetes and Metabolic Disease Unit, Department of Medicine, Surgery and Neurosciences, University of Siena, Siena, Italy
- Fondazione Umberto Di Mario, c/o Toscana Life Sciences, Siena, Italy
| | - Daniela Fignani
- Diabetes and Metabolic Disease Unit, Department of Medicine, Surgery and Neurosciences, University of Siena, Siena, Italy
- Fondazione Umberto Di Mario, c/o Toscana Life Sciences, Siena, Italy
| | - Laura Nigi
- Diabetes and Metabolic Disease Unit, Department of Medicine, Surgery and Neurosciences, University of Siena, Siena, Italy
- Fondazione Umberto Di Mario, c/o Toscana Life Sciences, Siena, Italy
| | - Caterina Formichi
- Diabetes and Metabolic Disease Unit, Department of Medicine, Surgery and Neurosciences, University of Siena, Siena, Italy
- Fondazione Umberto Di Mario, c/o Toscana Life Sciences, Siena, Italy
| | - Elena Aiello
- Diabetes and Metabolic Disease Unit, Department of Medicine, Surgery and Neurosciences, University of Siena, Siena, Italy
- Fondazione Umberto Di Mario, c/o Toscana Life Sciences, Siena, Italy
| | - Stefano Auddino
- Diabetes and Metabolic Disease Unit, Department of Medicine, Surgery and Neurosciences, University of Siena, Siena, Italy
- Fondazione Umberto Di Mario, c/o Toscana Life Sciences, Siena, Italy
| | - Giuseppe Quero
- Dipartimento di Medicina e Chirurgia Traslazionale, Università Cattolica del Sacro Cuore, Roma, Italy
- Pancreatic surgery unit, Pancreatic Advanced Research Center (CRMPG), Fondazione Policlinico Universitario Agostino Gemelli IRCCS, Roma, Italy
| | - Chiara M A Cefalo
- Endocrinologia e Diabetologia, Fondazione Policlinico Universitario Agostino Gemelli IRCCS, Roma, Italy
- Dipartimento di Medicina e Chirurgia Traslazionale, Università Cattolica del Sacro Cuore, Roma, Italy
| | - Francesca Cinti
- Endocrinologia e Diabetologia, Fondazione Policlinico Universitario Agostino Gemelli IRCCS, Roma, Italy
- Dipartimento di Medicina e Chirurgia Traslazionale, Università Cattolica del Sacro Cuore, Roma, Italy
| | - Andrea Mari
- Institute of Neuroscience, National Research Council, Padova, Italy
| | - Pietro M Ferraro
- Dipartimento di Medicina e Chirurgia Traslazionale, Università Cattolica del Sacro Cuore, Roma, Italy
- U.O.S. Terapia Conservativa della Malattia Renale Cronica, Fondazione Policlinico Universitario A. Gemelli IRCCS, Roma, Italy
| | - Alfredo Pontecorvi
- Endocrinologia e Diabetologia, Fondazione Policlinico Universitario Agostino Gemelli IRCCS, Roma, Italy
- Dipartimento di Medicina e Chirurgia Traslazionale, Università Cattolica del Sacro Cuore, Roma, Italy
| | - Sergio Alfieri
- Dipartimento di Medicina e Chirurgia Traslazionale, Università Cattolica del Sacro Cuore, Roma, Italy
- Pancreatic surgery unit, Pancreatic Advanced Research Center (CRMPG), Fondazione Policlinico Universitario Agostino Gemelli IRCCS, Roma, Italy
| | - Andrea Giaccari
- Endocrinologia e Diabetologia, Fondazione Policlinico Universitario Agostino Gemelli IRCCS, Roma, Italy.
- Dipartimento di Medicina e Chirurgia Traslazionale, Università Cattolica del Sacro Cuore, Roma, Italy.
| | - Francesco Dotta
- Diabetes and Metabolic Disease Unit, Department of Medicine, Surgery and Neurosciences, University of Siena, Siena, Italy.
- Fondazione Umberto Di Mario, c/o Toscana Life Sciences, Siena, Italy.
| | - Teresa Mezza
- Dipartimento di Medicina e Chirurgia Traslazionale, Università Cattolica del Sacro Cuore, Roma, Italy
- Digestive Disease Center, Fondazione Policlinico Universitario Agostino Gemelli IRCCS, Roma, Italy
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Cook TW, Wilstermann AM, Mitchell JT, Arnold NE, Rajasekaran S, Bupp CP, Prokop JW. Understanding Insulin in the Age of Precision Medicine and Big Data: Under-Explored Nature of Genomics. Biomolecules 2023; 13:257. [PMID: 36830626 PMCID: PMC9953665 DOI: 10.3390/biom13020257] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2022] [Revised: 01/20/2023] [Accepted: 01/26/2023] [Indexed: 01/31/2023] Open
Abstract
Insulin is amongst the human genome's most well-studied genes/proteins due to its connection to metabolic health. Within this article, we review literature and data to build a knowledge base of Insulin (INS) genetics that influence transcription, transcript processing, translation, hormone maturation, secretion, receptor binding, and metabolism while highlighting the future needs of insulin research. The INS gene region has 2076 unique variants from population genetics. Several variants are found near the transcriptional start site, enhancers, and following the INS transcripts that might influence the readthrough fusion transcript INS-IGF2. This INS-IGF2 transcript splice site was confirmed within hundreds of pancreatic RNAseq samples, lacks drift based on human genome sequencing, and has possible elevated expression due to viral regulation within the liver. Moreover, a rare, poorly characterized African population-enriched variant of INS-IGF2 results in a loss of the stop codon. INS transcript UTR variants rs689 and rs3842753, associated with type 1 diabetes, are found in many pancreatic RNAseq datasets with an elevation of the 3'UTR alternatively spliced INS transcript. Finally, by combining literature, evolutionary profiling, and structural biology, we map rare missense variants that influence preproinsulin translation, proinsulin processing, dimer/hexamer secretory storage, receptor activation, and C-peptide detection for quasi-insulin blood measurements.
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Affiliation(s)
- Taylor W. Cook
- Department of Pediatrics and Human Development, College of Human Medicine, Michigan State University, Grand Rapids, MI 49503, USA
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing, MI 48824, USA
| | | | - Jackson T. Mitchell
- Department of Pediatrics and Human Development, College of Human Medicine, Michigan State University, Grand Rapids, MI 49503, USA
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing, MI 48824, USA
| | - Nicholas E. Arnold
- Department of Pediatrics and Human Development, College of Human Medicine, Michigan State University, Grand Rapids, MI 49503, USA
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing, MI 48824, USA
| | - Surender Rajasekaran
- Department of Pediatrics and Human Development, College of Human Medicine, Michigan State University, Grand Rapids, MI 49503, USA
- Office of Research, Corewell Health, Grand Rapids, MI 49503, USA
| | - Caleb P. Bupp
- Department of Pediatrics and Human Development, College of Human Medicine, Michigan State University, Grand Rapids, MI 49503, USA
- Division of Medical Genetics, Corewell Health, Grand Rapids, MI 49503, USA
| | - Jeremy W. Prokop
- Department of Pediatrics and Human Development, College of Human Medicine, Michigan State University, Grand Rapids, MI 49503, USA
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing, MI 48824, USA
- Office of Research, Corewell Health, Grand Rapids, MI 49503, USA
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8
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Sosa Alvarado C, Yang K, Qiu H, Mills E, Fouhse JM, Ju T, Buteau J, Field CJ, Willing BP, Chan CB. Transient antibiotic-induced changes in the neonatal swine intestinal microbiota impact islet expression profiles reducing subsequent function. Am J Physiol Regul Integr Comp Physiol 2021; 321:R303-R316. [PMID: 34259034 DOI: 10.1152/ajpregu.00090.2021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Neonatal antibiotics administered to human infants initiate gut microbiota dysbiosis that may have long-term effects on body weight and metabolism. We examined antibiotic-induced adaptations in pancreatic islets of the piglet, a well-accepted model of human infant microbiota and pancreas development. Neonatal piglets randomized to amoxicillin [30 mg/kg body wt/day; n = 7, antibiotic (ANTI)] or placebo [vehicle control; n = 7, control (CON)] from postnatal day (PND)0-13 were euthanized at PND7, 14, and 49. The metabolic phenotype along with functional, immunohistological, and transcriptional phenotypes of the pancreatic islets were studied. The gut microbiome was characterized by 16S rRNA gene sequencing, and microbial metabolites and microbiome-sensitive host molecules were measured. Compared with CON, ANTI PND7 piglets had elevated transcripts of genes involved in glucagon-like peptide 1 ((GLP-1) synthesis or signaling in islets (P < 0.05) coinciding with higher plasma GLP-1 (P = 0.11), along with increased tumor necrosis factor α (Tnf) (P < 0.05) and protegrin 1 (Npg1) (P < 0.05). Antibiotic-induced relative increases in Escherichia, Coprococcus, Ruminococcus, Dehalobacterium, and Oscillospira of the ileal microbiome at PND7 normalized after antibiotic withdrawal. In ANTI islets at PND14, the expression of key regulators pancreatic and duodenal homeobox 1 (Pdx1), insulin-like growth factor-2 (Igf2), and transcription factor 7-like 2 (Tcf7l2) was downregulated, preceding a 40% reduction of β-cell area (P < 0.01) and islet insulin content at PND49 (P < 0.05). At PND49, a twofold elevated plasma insulin concentration (P = 0.07) was observed in ANTI compared with CON. We conclude that antibiotic treatment of neonatal piglets elicited gut microbial changes accompanied by phasic alterations in key regulatory genes in pancreatic islets at PND7 and 14. By PND49, reduced β-cell area and islet insulin content were accompanied by elevated nonfasted insulin despite normoglycemia, indicative of islet stress.
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Affiliation(s)
- Carla Sosa Alvarado
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, Alberta, Canada
| | - Kaiyuan Yang
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, Alberta, Canada
| | - Hongbo Qiu
- Department of Physiology, University of Alberta, Edmonton, Alberta, Canada
| | - Erinn Mills
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, Alberta, Canada
| | - Janelle M Fouhse
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, Alberta, Canada
| | - Tingting Ju
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, Alberta, Canada
| | - Jean Buteau
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, Alberta, Canada
| | - Catherine J Field
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, Alberta, Canada
| | - Benjamin P Willing
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, Alberta, Canada
| | - Catherine B Chan
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, Alberta, Canada.,Department of Physiology, University of Alberta, Edmonton, Alberta, Canada
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9
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Sasi USS, Ganapathy S, Palayyan SR, Gopal RK. Mitochondria Associated Membranes (MAMs): Emerging Drug Targets for Diabetes. Curr Med Chem 2020; 27:3362-3385. [PMID: 30747057 DOI: 10.2174/0929867326666190212121248] [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: 07/16/2018] [Revised: 01/01/2019] [Accepted: 02/04/2019] [Indexed: 12/13/2022]
Abstract
MAMs, the physical association between the Endoplasmic Reticulum (ER) and mitochondria are, functional domains performing a significant role in the maintenance of cellular homeostasis. It is evolving as an important signaling center that coordinates nutrient and hormonal signaling for the proper regulation of hepatic insulin action and glucose homeostasis. Moreover, MAMs can be considered as hot spots for the transmission of stress signals from ER to mitochondria. The altered interaction between ER and mitochondria results in the amendment of several insulin-sensitive tissues, revealing the role of MAMs in glucose homeostasis. The development of mitochondrial dysfunction, ER stress, altered lipid and Ca2+ homeostasis are typically co-related with insulin resistance and β cell dysfunction. But little facts are known about the role played by these stresses in the development of metabolic disorders. In this review, we highlight the mechanisms involved in maintaining the contact site with new avenues of investigations for the development of novel preventive and therapeutic targets for T2DM.
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Affiliation(s)
- U S Swapna Sasi
- Biochemistry and Molecular Mechanism Laboratory, Agro-processing and Technology Division, CSIRNational Institute for Interdisciplinary Science and Technology (NIIST), Thiruvananthapuram, Kerala 695019, India.,Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
| | - Sindhu Ganapathy
- Biochemistry and Molecular Mechanism Laboratory, Agro-processing and Technology Division, CSIRNational Institute for Interdisciplinary Science and Technology (NIIST), Thiruvananthapuram, Kerala 695019, India
| | - Salin Raj Palayyan
- Biochemistry and Molecular Mechanism Laboratory, Agro-processing and Technology Division, CSIRNational Institute for Interdisciplinary Science and Technology (NIIST), Thiruvananthapuram, Kerala 695019, India.,Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
| | - Raghu K Gopal
- Biochemistry and Molecular Mechanism Laboratory, Agro-processing and Technology Division, CSIRNational Institute for Interdisciplinary Science and Technology (NIIST), Thiruvananthapuram, Kerala 695019, India.,Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
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10
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Tans R, van Rijswijck DMH, Davidson A, Hannam R, Ricketts B, Tack CJ, Wessels HJCT, Gloerich J, van Gool AJ. Affimers as an alternative to antibodies for protein biomarker enrichment. Protein Expr Purif 2020; 174:105677. [PMID: 32461183 DOI: 10.1016/j.pep.2020.105677] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2020] [Revised: 05/15/2020] [Accepted: 05/17/2020] [Indexed: 12/31/2022]
Abstract
INTRODUCTION Assessing the specificity of protein binders is an essential first step in protein biomarker assay development. Affimers are novel protein binders and can potentially replace antibodies in multiple protein capture-based assays. Affimers are selected for their high specificity against the target protein and have benefits over antibodies like batch-to-batch reproducibility and are stable across a wide range of chemical conditions. Here we mimicked a typical initial screening of affimers and commercially available monoclonal antibodies against two non-related proteins, IL-37b and proinsulin, to assess the potential of affimers as alternative to antibodies. METHODS Binding specificity of anti-IL-37b and anti-proinsulin affimers and antibodies was investigated via magnetic bead-based capture of their recombinant protein targets in human plasma. Captured proteins were analyzed using SDS-PAGE, Coomassie blue staining, Western blotting and LC-MS/MS-based proteomics. RESULTS All affimers and antibodies were able to bind their target protein in human plasma. Gel and LC-MS/MS analysis showed that both affimer and antibody-based captures resulted in co-purified background proteins. However, affimer-based captures showed the highest relative enrichment of IL-37b and proinsulin. CONCLUSIONS For both proteins tested, affimers show higher specificity in purifying their target proteins from human plasma compared to monoclonal antibodies. These results indicate that affimers are promising antibody-replacement tools for protein biomarker assay development.
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Affiliation(s)
- Roel Tans
- Translational Metabolic Laboratory, Department of Laboratory Medicine, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Geert Grooteplein Zuid 10, 6525, GA, Nijmegen, the Netherlands
| | - Danique M H van Rijswijck
- Translational Metabolic Laboratory, Department of Laboratory Medicine, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Geert Grooteplein Zuid 10, 6525, GA, Nijmegen, the Netherlands
| | - Alex Davidson
- Avacta Life Sciences, Unit 20, Ash Way, Thorp Arch Estate & Retail Park, Wetherby, LS23 7FA, United Kingdom
| | - Ryan Hannam
- Avacta Life Sciences, Unit 20, Ash Way, Thorp Arch Estate & Retail Park, Wetherby, LS23 7FA, United Kingdom
| | - Bryon Ricketts
- Avacta Life Sciences, Unit 20, Ash Way, Thorp Arch Estate & Retail Park, Wetherby, LS23 7FA, United Kingdom
| | - Cees J Tack
- Department of Internal Medicine, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Geert Grooteplein Zuid 10, 6525, GA, Nijmegen, the Netherlands
| | - Hans J C T Wessels
- Translational Metabolic Laboratory, Department of Laboratory Medicine, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Geert Grooteplein Zuid 10, 6525, GA, Nijmegen, the Netherlands
| | - Jolein Gloerich
- Translational Metabolic Laboratory, Department of Laboratory Medicine, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Geert Grooteplein Zuid 10, 6525, GA, Nijmegen, the Netherlands
| | - Alain J van Gool
- Translational Metabolic Laboratory, Department of Laboratory Medicine, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Geert Grooteplein Zuid 10, 6525, GA, Nijmegen, the Netherlands.
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11
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Piganelli JD, Mamula MJ, James EA. The Role of β Cell Stress and Neo-Epitopes in the Immunopathology of Type 1 Diabetes. Front Endocrinol (Lausanne) 2020; 11:624590. [PMID: 33679609 PMCID: PMC7930070 DOI: 10.3389/fendo.2020.624590] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/31/2020] [Accepted: 12/23/2020] [Indexed: 12/15/2022] Open
Abstract
Due to their secretory function, β cells are predisposed to higher levels of endoplasmic reticulum (ER) stress and greater sensitivity to inflammation than other cell types. These stresses elicit changes in β cells that alter their function and immunogenicity, including defective ribosomal initiation, post-translational modifications (PTMs) of endogenous β cell proteins, and alternative splicing. Multiple published reports confirm the presence of not only CD8+ T cells, but also autoreactive CD4+ T cells within pancreatic islets. Although the specificities of T cells that infiltrate human islets are incompletely characterized, they have been confirmed to include neo-epitopes that are formed through stress-related enzymatic modifications of β cell proteins. This article summarizes emerging knowledge about stress-induced changes in β cells and data supporting a role for neo-antigen formation and cross-talk between immune cells and β cells that provokes autoimmune attack - leading to a breakdown in tissue-specific tolerance in subjects who develop type 1 diabetes.
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Affiliation(s)
- Jon D. Piganelli
- Division of Pediatric Surgery, Department of Surgery, Children’s Hospital of Pittsburgh, University of Pittsburgh School of Medicine, Pittsburgh, PA, United States
| | - Mark J. Mamula
- Section of Rheumatology, Department of Medicine, Yale School of Medicine, New Haven, CT, United States
| | - Eddie A. James
- Translational Research Program, Benaroya Research Institute at Virginia Mason, Seattle, WA, United States
- *Correspondence: Eddie A. James,
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12
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Ghiasi SM, Dahlby T, Hede Andersen C, Haataja L, Petersen S, Omar-Hmeadi M, Yang M, Pihl C, Bresson SE, Khilji MS, Klindt K, Cheta O, Perone MJ, Tyrberg B, Prats C, Barg S, Tengholm A, Arvan P, Mandrup-Poulsen T, Marzec MT. Endoplasmic Reticulum Chaperone Glucose-Regulated Protein 94 Is Essential for Proinsulin Handling. Diabetes 2019; 68:747-760. [PMID: 30670477 PMCID: PMC6425875 DOI: 10.2337/db18-0671] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/15/2018] [Accepted: 12/26/2018] [Indexed: 12/18/2022]
Abstract
Although endoplasmic reticulum (ER) chaperone binding to mutant proinsulin has been reported, the role of protein chaperones in the handling of wild-type proinsulin is underinvestigated. Here, we have explored the importance of glucose-regulated protein 94 (GRP94), a prominent ER chaperone known to fold insulin-like growth factors, in proinsulin handling within β-cells. We found that GRP94 coimmunoprecipitated with proinsulin and that inhibition of GRP94 function and/or expression reduced glucose-dependent insulin secretion, shortened proinsulin half-life, and lowered intracellular proinsulin and insulin levels. This phenotype was accompanied by post-ER proinsulin misprocessing and higher numbers of enlarged insulin granules that contained amorphic material with reduced immunogold staining for mature insulin. Insulin granule exocytosis was accelerated twofold, but the secreted insulin had diminished bioactivity. Moreover, GRP94 knockdown or knockout in β-cells selectively activated protein kinase R-like endoplasmic reticulum kinase (PERK), without increasing apoptosis levels. Finally, GRP94 mRNA was overexpressed in islets from patients with type 2 diabetes. We conclude that GRP94 is a chaperone crucial for proinsulin handling and insulin secretion.
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Affiliation(s)
- Seyed Mojtaba Ghiasi
- Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Tina Dahlby
- Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | | | - Leena Haataja
- Division of Metabolism, Endocrinology, & Diabetes, University of Michigan Medical Center, Ann Arbor, MI
| | - Sólrun Petersen
- Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | | | - Mingyu Yang
- Department of Medical Cell Biology, Uppsala University, Uppsala, Sweden
| | - Celina Pihl
- Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | | | - Muhammad Saad Khilji
- Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Kristian Klindt
- Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Oana Cheta
- Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Marcelo J Perone
- Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
- Instituto de Investigación en Biomedicina de Buenos Aires (IBioBA)-CONICET-Partner Institute of the Max Planck Society, Polo Científico Tecnológico, Buenos Aires, Argentina
| | - Björn Tyrberg
- Translational Science, Cardiovascular, Renal and Metabolism, IMED Biotech Unit, AstraZeneca, Gothenburg, Sweden
| | - Clara Prats
- Center for Healthy Ageing, Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Sebastian Barg
- Department of Medical Cell Biology, Uppsala University, Uppsala, Sweden
| | - Anders Tengholm
- Department of Medical Cell Biology, Uppsala University, Uppsala, Sweden
| | - Peter Arvan
- Division of Metabolism, Endocrinology, & Diabetes, University of Michigan Medical Center, Ann Arbor, MI
| | | | - Michal Tomasz Marzec
- Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
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13
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Hu Y, Gao Y, Zhang M, Deng KY, Singh R, Tian Q, Gong Y, Pan Z, Liu Q, Boisclair YR, Long Q. Endoplasmic Reticulum-Associated Degradation (ERAD) Has a Critical Role in Supporting Glucose-Stimulated Insulin Secretion in Pancreatic β-Cells. Diabetes 2019; 68:733-746. [PMID: 30626610 DOI: 10.2337/db18-0624] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/04/2018] [Accepted: 12/19/2018] [Indexed: 11/13/2022]
Abstract
The molecular underpinnings of β-cell dysfunction and death leading to diabetes are not fully elucidated. The objective of the current study was to investigate the role of endoplasmic reticulum-associated degradation (ERAD) in pancreatic β-cells. Chemically induced ERAD deficiency in the rat insulinoma cell line INS-1 markedly reduced glucose-stimulated insulin secretion (GSIS). The mechanistic basis for this effect was studied in cells and mice lacking ERAD as a consequence of genetic ablation of the core ERAD protein SEL1L. Targeted disruption of SEL1L in INS-1 cells and in mouse pancreatic β-cells impaired ERAD and led to blunted GSIS. Additionally, mice with SEL1L deletion in β-cells were chronically hyperglycemic after birth and increasingly glucose intolerant over time. SEL1L absence caused an entrapment of proinsulin in the endoplasmic reticulum compartment in both INS-1 cells and mouse pancreatic β-cells. Both folding-competent and folding-deficient proinsulin can physiologically interact with and be efficiently degraded by HRD1, the E3 ubiquitin ligase subunit of the ERAD complex. GSIS impairment in insulinoma cells was accompanied by a reduced intracellular Ca2+ ion level, overproduction of reactive oxygen species, and lowered mitochondrial membrane potential. Together, these findings suggest that ERAD plays a pivotal role in supporting pancreatic β-cell function by targeting wild-type and folding-deficient proinsulin for proteosomal degradation. ERAD deficiency may contribute to the development of diabetes by affecting proinsulin processing in the ER, intracellular Ca2+ concentration, and mitochondrial function.
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Affiliation(s)
- Yabing Hu
- Jiangsu Key Laboratory of Neuropsychiatric Diseases and Cam-Su Genomic Resource Center, Medical College of Soochow University, Suzhou, People's Republic of China
| | - Yuanyuan Gao
- Jiangsu Key Laboratory of Neuropsychiatric Diseases and Cam-Su Genomic Resource Center, Medical College of Soochow University, Suzhou, People's Republic of China
| | - Manman Zhang
- Jiangsu Key Laboratory of Neuropsychiatric Diseases and Cam-Su Genomic Resource Center, Medical College of Soochow University, Suzhou, People's Republic of China
| | - Ke-Yu Deng
- Institute of Translational Medicine, Nanchang University, Nanchang, People's Republic of China
| | - Rajni Singh
- Department of Animal Science, Cornell University, Ithaca, NY
| | - Qiongge Tian
- Jiangsu Key Laboratory of Neuropsychiatric Diseases and Cam-Su Genomic Resource Center, Medical College of Soochow University, Suzhou, People's Republic of China
| | - Yi Gong
- Jiangsu Key Laboratory of Neuropsychiatric Diseases and Cam-Su Genomic Resource Center, Medical College of Soochow University, Suzhou, People's Republic of China
| | - Zhixiong Pan
- Jiangsu Key Laboratory of Neuropsychiatric Diseases and Cam-Su Genomic Resource Center, Medical College of Soochow University, Suzhou, People's Republic of China
| | - Qingqing Liu
- Jiangsu Key Laboratory of Neuropsychiatric Diseases and Cam-Su Genomic Resource Center, Medical College of Soochow University, Suzhou, People's Republic of China
| | | | - Qiaoming Long
- Jiangsu Key Laboratory of Neuropsychiatric Diseases and Cam-Su Genomic Resource Center, Medical College of Soochow University, Suzhou, People's Republic of China
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14
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Vong CT, Tseng HHL, Kwan YW, Lee SMY, Hoi MPM. Novel protective effect of O-1602 and abnormal cannabidiol, GPR55 agonists, on ER stress-induced apoptosis in pancreatic β-cells. Biomed Pharmacother 2019; 111:1176-1186. [DOI: 10.1016/j.biopha.2018.12.126] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2018] [Revised: 12/27/2018] [Accepted: 12/30/2018] [Indexed: 01/09/2023] Open
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15
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Elksnis A, Martinell M, Eriksson O, Espes D. Heterogeneity of Metabolic Defects in Type 2 Diabetes and Its Relation to Reactive Oxygen Species and Alterations in Beta-Cell Mass. Front Physiol 2019; 10:107. [PMID: 30837889 PMCID: PMC6383038 DOI: 10.3389/fphys.2019.00107] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2018] [Accepted: 01/28/2019] [Indexed: 12/21/2022] Open
Abstract
Type 2 diabetes (T2D) is a complex and heterogeneous disease which affects millions of people worldwide. The classification of diabetes is at an interesting turning point and there have been several recent reports on sub-classification of T2D based on phenotypical and metabolic characteristics. An important, and perhaps so far underestimated, factor in the pathophysiology of T2D is the role of oxidative stress and reactive oxygen species (ROS). There are multiple pathways for excessive ROS formation in T2D and in addition, beta-cells have an inherent deficit in the capacity to cope with oxidative stress. ROS formation could be causal, but also contribute to a large number of the metabolic defects in T2D, including beta-cell dysfunction and loss. Currently, our knowledge on beta-cell mass is limited to autopsy studies and based on comparisons with healthy controls. The combined evidence suggests that beta-cell mass is unaltered at onset of T2D but that it declines progressively. In order to better understand the pathophysiology of T2D, to identify and evaluate novel treatments, there is a need for in vivo techniques able to quantify beta-cell mass. Positron emission tomography holds great potential for this purpose and can in addition map metabolic defects, including ROS activity, in specific tissue compartments. In this review, we highlight the different phenotypical features of T2D and how metabolic defects impact oxidative stress and ROS formation. In addition, we review the literature on alterations of beta-cell mass in T2D and discuss potential techniques to assess beta-cell mass and metabolic defects in vivo.
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Affiliation(s)
- Andris Elksnis
- Department of Medical Cell Biology, Uppsala University, Uppsala, Sweden
| | - Mats Martinell
- Department of Public Health and Caring Sciences, Uppsala University, Uppsala, Sweden
| | - Olof Eriksson
- Science for Life Laboratory, Department of Medicinal Chemistry, Uppsala University, Uppsala, Sweden
| | - Daniel Espes
- Department of Medical Cell Biology, Uppsala University, Uppsala, Sweden
- Department of Medical Sciences, Uppsala University, Uppsala, Sweden
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16
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Arasi FP, Shahrestanaki MK, Aghaei M. A2a adenosine receptor agonist improves endoplasmic reticulum stress in MIN6 cell line through protein kinase A/ protein kinase B/ Cyclic adenosine monophosphate response element-binding protein/ and Growth Arrest And DNA-Damage-Inducible 34/ eukaryotic Initiation Factor 2α pathways. J Cell Physiol 2018; 234:10500-10511. [PMID: 30417358 DOI: 10.1002/jcp.27719] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2018] [Accepted: 10/16/2018] [Indexed: 02/06/2023]
Abstract
Endoplasmic reticulum (ER) stress is one of the main molecular events underlying pancreatic beta cell (PBC) failure, apoptosis, and a decrease in insulin secretion. Recent studies have highlighted the fundamental role of A2a adenosine receptor (A2aR) in potentiation of insulin secretion and proliferation of PBCs. However, possible protective effects of A2aR signaling against ER stress have not been elucidated yet. Thus, in the present study, we aimed to investigate the effects of A2aR activation in MIN6 beta cells undergoing tunicamycin (TM)-mediated ER stress. A2aR expression and activity were evaluated using real-time polymerase chain reaction and measurement of the cyclic adenosine monophosphate (cAMP), protein kinase A (PKA), phospho-protein kinase B or Akt (p-Akt)/Akt, and phospho-Cyclic adenosine monophosphate response element-binding protein/CREB levels in response to a specific agonist (CGS 21680). Survival and proliferation in TM and CGS 21680 cotreated cells were evaluated using 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), annexin V-fluorescein isothiocyanate (FITC)/propidium iodide staining, colony formation, and 5-bromo-2'-deoxyuridine (Brdu) assays. In addition, the effects of A2aR stimulation on insulin secretion were evaluated using the enzyme-linked immunosorbent assay. B-cell lymphoma 2 (Bcl-2), phospho-eukaryotic Initiation Factor 2α (p-eIF2α)/eIF2α, growth arrest and DNA-damage-inducible 34 (GADD34), X-box binding protein 1 (XBP-1), spliced X-box binding protein 1 (XBP-1s), immunoglobulin heavy-chain-binding protein (BIP), and CCAAT-enhancer-binding protein homologous protein (CHOP) levels were evaluated using western blotting. Our results showed a decrease in A2aR expression and p-Akt/Akt and p-CREB/CREB levels in TM-pretreated cells. We also mentioned that CGS 21680 effectively increased cell survival, proliferation, and insulin secretion in TM-treated cells. The antiapoptotic effects were possibly mediated through Bcl-2 upregulation. Our western blotting results indicated that A2aR effectively downregulated p-eIF2α/eIF2α, XBP-1, XBP-1s, BIP, and CHOP levels, whereas GADD34 was upregulated. Altogether, the present study revealed that A2aR signaling through PKA/Akt/CREB mediators alleviated TM cytotoxicity effects in MIN6 beta cells. Thus, the stimulation of this receptor was seen as a new approach to control ER stress in the PBC cells.
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Affiliation(s)
- Fatemeh P Arasi
- Department of Clinical Biochemistry, School of Pharmacy & Pharmaceutical Sciences, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Mohammad K Shahrestanaki
- Department of Clinical Biochemistry, School of Pharmacy & Pharmaceutical Sciences, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Mahmoud Aghaei
- Department of Clinical Biochemistry, School of Pharmacy & Pharmaceutical Sciences, Isfahan University of Medical Sciences, Isfahan, Iran
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17
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Jeong DE, Heo S, Han JH, Lee EY, Kulkarni RN, Kim W. Glucose Controls the Expression of Polypyrimidine Tract-Binding Protein 1 via the Insulin Receptor Signaling Pathway in Pancreatic β Cells. Mol Cells 2018; 41:909-916. [PMID: 30165730 PMCID: PMC6199568 DOI: 10.14348/molcells.2018.0147] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2018] [Revised: 08/06/2018] [Accepted: 08/09/2018] [Indexed: 01/04/2023] Open
Abstract
In pancreatic β cells, glucose stimulates the biosynthesis of insulin at transcriptional and post-transcriptional levels. The RNA-binding protein, polypyrimidine tract-binding protein 1 (PTBP1), also named hnRNP I, acts as a critical mediator of insulin biosynthesis through binding to the pyrimidine-rich region in the 3'-untranslated region (UTR) of insulin mRNA. However, the underlying mechanism that regulates its expression in β cells is unclear. Here, we report that glucose induces the expression of PTBP1 via the insulin receptor (IR) signaling pathway in β cells. PTBP1 is present in β cells of both mouse and monkey, where its levels are increased by glucose and insulin, but not by insulin-like growth factor 1. PTBP1 levels in immortalized β cells established from wild-type (βIRWT) mice are higher than levels in β cells established from IR-null (βIRKO) mice, and ectopic re-expression of IR-WT in βIRKO cells restored PTBP1 levels. However, PTBP1 levels were not altered in βIRKO cells transfected with IR-3YA, in which the Tyr1158/1162/1163 residues are substituted with Ala. Consistently, treatment with glucose or insulin elevated PTBP1 levels in βIRWT cells, but not in βIRKO cells. In addition, silencing Akt significantly lowered PTBP1 levels. Thus, our results identify insulin as a pivotal mediator of glucose-induced PTBP1 expression in pancreatic β cells.
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Affiliation(s)
- Da Eun Jeong
- Department of Molecular Science and Technology, Ajou University, Suwon 16499,
Korea
| | - Sungeun Heo
- Department of Molecular Science and Technology, Ajou University, Suwon 16499,
Korea
| | - Ji Hye Han
- Department of Molecular Science and Technology, Ajou University, Suwon 16499,
Korea
| | - Eun-young Lee
- Department of Molecular Science and Technology, Ajou University, Suwon 16499,
Korea
| | - Rohit N. Kulkarni
- Department of Islet Cell and Regenerative Biology, Joslin Diabetes Center and Department of Medicine, Harvard Medical School, and Harvard Stem Cell Institute, Boston, MA 02215,
USA
| | - Wook Kim
- Department of Molecular Science and Technology, Ajou University, Suwon 16499,
Korea
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18
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Mészáros G, Pasquier A, Vivot K, Goginashvili A, Ricci R. Lysosomes in nutrient signalling: A focus on pancreatic β-cells. Diabetes Obes Metab 2018; 20 Suppl 2:104-115. [PMID: 30230186 DOI: 10.1111/dom.13389] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/18/2018] [Revised: 05/24/2018] [Accepted: 05/28/2018] [Indexed: 01/12/2023]
Abstract
Regulated insulin secretion from pancreatic β-cells is a major process maintaining glucose homeostasis in mammals. Enhancing insulin release in response to chronic nutrient overload and obesity-related insulin resistance (pre-diabetes) requires several adaptive cellular mechanisms maintaining β-cell health under such stresses. Once these mechanisms are overwhelmed, β-cell failure occurs leading to full-blown Type 2 Diabetes (T2D). Nutrient-dependent macroautophagy represents one such adaptive mechanism in β-cells. While macroautophagy levels are high and protective in β-cells in pre-diabetes, they decrease at later stages contributing to β-cell failure. However, mechanisms compromising macroautophagy in β-cells remain poorly understood. In this review, we discuss how recently discovered signalling cascades that emanate from the limiting membrane of lysosomes contribute to changes in macroautophagy flux in physiology and disease. In particular, these mechanisms are put into context with β-cell function highlighting most recently described links between nutrient-dependent lysosomal signalling pathways and insulin secretion. Understanding these mechanisms in response to metabolic stress might pave the way for development of more tailored treatment strategies aimed at preserving β-cell health.
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Affiliation(s)
- Gergő Mészáros
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, Illkirch, France
- Centre National de la Recherche Scientifique, UMR7104, Illkirch, France
- Institut National de la Santé et de la Recherche Médicale, U1258, Illkirch, France
- Université de Strasbourg, Strasbourg, France
- Laboratoire de Biochimie et de Biologie Moléculaire, Nouvel Hôpital Civil, Strasbourg, France
| | - Adrien Pasquier
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, Illkirch, France
- Centre National de la Recherche Scientifique, UMR7104, Illkirch, France
- Institut National de la Santé et de la Recherche Médicale, U1258, Illkirch, France
- Université de Strasbourg, Strasbourg, France
| | - Kevin Vivot
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, Illkirch, France
- Centre National de la Recherche Scientifique, UMR7104, Illkirch, France
- Institut National de la Santé et de la Recherche Médicale, U1258, Illkirch, France
- Université de Strasbourg, Strasbourg, France
| | - Alexander Goginashvili
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, Illkirch, France
- Centre National de la Recherche Scientifique, UMR7104, Illkirch, France
- Institut National de la Santé et de la Recherche Médicale, U1258, Illkirch, France
- Université de Strasbourg, Strasbourg, France
- Ludwig Institute for Cancer Research, Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, California
| | - Romeo Ricci
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, Illkirch, France
- Centre National de la Recherche Scientifique, UMR7104, Illkirch, France
- Institut National de la Santé et de la Recherche Médicale, U1258, Illkirch, France
- Université de Strasbourg, Strasbourg, France
- Laboratoire de Biochimie et de Biologie Moléculaire, Nouvel Hôpital Civil, Strasbourg, France
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19
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Liu M, Weiss MA, Arunagiri A, Yong J, Rege N, Sun J, Haataja L, Kaufman RJ, Arvan P. Biosynthesis, structure, and folding of the insulin precursor protein. Diabetes Obes Metab 2018; 20 Suppl 2:28-50. [PMID: 30230185 PMCID: PMC6463291 DOI: 10.1111/dom.13378] [Citation(s) in RCA: 126] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/25/2018] [Revised: 05/04/2018] [Accepted: 05/23/2018] [Indexed: 02/06/2023]
Abstract
Insulin synthesis in pancreatic β-cells is initiated as preproinsulin. Prevailing glucose concentrations, which oscillate pre- and postprandially, exert major dynamic variation in preproinsulin biosynthesis. Accompanying upregulated translation of the insulin precursor includes elements of the endoplasmic reticulum (ER) translocation apparatus linked to successful orientation of the signal peptide, translocation and signal peptide cleavage of preproinsulin-all of which are necessary to initiate the pathway of proper proinsulin folding. Evolutionary pressures on the primary structure of proinsulin itself have preserved the efficiency of folding ("foldability"), and remarkably, these evolutionary pressures are distinct from those protecting the ultimate biological activity of insulin. Proinsulin foldability is manifest in the ER, in which the local environment is designed to assist in the overall load of proinsulin folding and to favour its disulphide bond formation (while limiting misfolding), all of which is closely tuned to ER stress response pathways that have complex (beneficial, as well as potentially damaging) effects on pancreatic β-cells. Proinsulin misfolding may occur as a consequence of exuberant proinsulin biosynthetic load in the ER, proinsulin coding sequence mutations, or genetic predispositions that lead to an altered ER folding environment. Proinsulin misfolding is a phenotype that is very much linked to deficient insulin production and diabetes, as is seen in a variety of contexts: rodent models bearing proinsulin-misfolding mutants, human patients with Mutant INS-gene-induced Diabetes of Youth (MIDY), animal models and human patients bearing mutations in critical ER resident proteins, and, quite possibly, in more common variety type 2 diabetes.
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Affiliation(s)
- Ming Liu
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin, China 300052
- Division of Metabolism, Endocrinology & Diabetes, University of Michigan Medical School, Ann Arbor 48105 MI USA
| | - Michael A. Weiss
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis 46202 IN USA
- Department of Biochemistry, Case-Western Reserve University, Cleveland 44016 OH USA
| | - Anoop Arunagiri
- Division of Metabolism, Endocrinology & Diabetes, University of Michigan Medical School, Ann Arbor 48105 MI USA
| | - Jing Yong
- Degenerative Diseases Program, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA 92307 USA
| | - Nischay Rege
- Department of Biochemistry, Case-Western Reserve University, Cleveland 44016 OH USA
| | - Jinhong Sun
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin, China 300052
- Division of Metabolism, Endocrinology & Diabetes, University of Michigan Medical School, Ann Arbor 48105 MI USA
| | - Leena Haataja
- Division of Metabolism, Endocrinology & Diabetes, University of Michigan Medical School, Ann Arbor 48105 MI USA
| | - Randal J. Kaufman
- Degenerative Diseases Program, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA 92307 USA
| | - Peter Arvan
- Division of Metabolism, Endocrinology & Diabetes, University of Michigan Medical School, Ann Arbor 48105 MI USA
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20
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Kropp PA, Dunn JC, Carboneau BA, Stoffers DA, Gannon M. Cooperative function of Pdx1 and Oc1 in multipotent pancreatic progenitors impacts postnatal islet maturation and adaptability. Am J Physiol Endocrinol Metab 2018; 314:E308-E321. [PMID: 29351489 PMCID: PMC5966755 DOI: 10.1152/ajpendo.00260.2017] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The transcription factors pancreatic and duodenal homeobox 1 (Pdx1) and onecut1 (Oc1) are coexpressed in multipotent pancreatic progenitors (MPCs), but their expression patterns diverge in hormone-expressing cells, with Oc1 expression being extinguished in the endocrine lineage and Pdx1 being maintained at high levels in β-cells. We previously demonstrated that cooperative function of these two factors in MPCs is necessary for proper specification and differentiation of pancreatic endocrine cells. In those studies, we observed a persistent decrease in expression of the β-cell maturity factor MafA. We therefore hypothesized that Pdx1 and Oc1 cooperativity in MPCs impacts postnatal β-cell maturation and function. Here our model of Pdx1-Oc1 double heterozygosity was used to investigate the impact of haploinsufficiency for both of these factors on postnatal β-cell maturation, function, and adaptability. Examining mice at postnatal day (P) 14, we observed alterations in pancreatic insulin content in both Pdx1 heterozygotes and double heterozygotes. Gene expression analysis at this age revealed significantly decreased expression of many genes important for glucose-stimulated insulin secretion (e.g., Glut2, Pcsk1/2, Abcc8) exclusively in double heterozygotes. Analysis of P14 islets revealed an increase in the number of mixed islets in double heterozygotes. We predicted that double-heterozygous β-cells would have an impaired ability to respond to stress. Indeed, we observed that β-cell proliferation fails to increase in double heterozygotes in response to either high-fat diet or placental lactogen. We thus report here the importance of cooperation between regulatory factors early in development for postnatal islet maturation and adaptability.
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Affiliation(s)
- Peter A Kropp
- Department of Molecular Physiology and Biophysics, Vanderbilt University , Nashville, Tennessee
| | - Jennifer C Dunn
- Department of Veterans Affairs, Tennessee Valley Health Authority, Vanderbilt University , Nashville, Tennessee
- Department of Medicine, Vanderbilt University , Nashville, Tennessee
| | - Bethany A Carboneau
- Department of Veterans Affairs, Tennessee Valley Health Authority, Vanderbilt University , Nashville, Tennessee
- Department of Molecular Physiology and Biophysics, Vanderbilt University , Nashville, Tennessee
| | - Doris A Stoffers
- Department of Medicine, Institute for Diabetes, Obesity, and Metabolism, Perelman School of Medicine, University of Pennsylvania , Philadelphia, Pennsylvania
| | - Maureen Gannon
- Department of Veterans Affairs, Tennessee Valley Health Authority, Vanderbilt University , Nashville, Tennessee
- Department of Molecular Physiology and Biophysics, Vanderbilt University , Nashville, Tennessee
- Department of Medicine, Vanderbilt University , Nashville, Tennessee
- Department of Cell and Developmental Biology, Vanderbilt University , Nashville, Tennessee
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21
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Mehmeti I, Lortz S, Avezov E, Jörns A, Lenzen S. ER-resident antioxidative GPx7 and GPx8 enzyme isoforms protect insulin-secreting INS-1E β-cells against lipotoxicity by improving the ER antioxidative capacity. Free Radic Biol Med 2017; 112:121-130. [PMID: 28751022 DOI: 10.1016/j.freeradbiomed.2017.07.021] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/07/2017] [Revised: 07/20/2017] [Accepted: 07/22/2017] [Indexed: 12/16/2022]
Abstract
Increased circulating levels of saturated fatty acids (FFAs) and glucose are considered to be major mediators of β-cell dysfunction and death in T2DM. Although it has been proposed that endoplasmic reticulum (ER) and oxidative stress play a crucial role in gluco/lipotoxicity, their interplay and relative contribution to β-cell dysfunction and apoptosis has not been fully elucidated. In addition it is still unclear how palmitate - the physiologically most abundant long-chain saturated FFA - elicits ER stress and which immediate signals commit β-cells to apoptosis. To study the underlying mechanisms of palmitate-mediated ER stress and β-cell toxicity, we exploited the observation that the recently described ER-resident GPx7 and GPx8 are not expressed in rat β-cells. Expression of GPx7 or GPx8 attenuated FFAs-mediated H2O2 generation, ER stress, and apoptosis induction. These results could be confirmed by a H2O2-specific inactivating ER catalase, indicating that accumulation of H2O2 in the ER lumen is critical in FFA-induced ER stress. Furthermore, neither the expression of GPx7 nor of GPx8 increased insulin content or facilitated disulfide bond formation in insulin-secreting INS-1E cells. Hence, reduction of H2O2 by ER-GPx isoforms is not rate-limiting in oxidative protein folding in rat β-cells. These data suggest that FFA-mediated ER stress is partially dependent on oxidative stress and selective expression of GPx7 or GPx8 improves the ER antioxidative capacity of rat β-cells without compromising insulin production and the oxidative protein folding machinery.
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Affiliation(s)
- Ilir Mehmeti
- Institute of Clinical Biochemistry, Hannover Medical School, Hannover, Germany.
| | - Stephan Lortz
- Institute of Clinical Biochemistry, Hannover Medical School, Hannover, Germany
| | - Edward Avezov
- University of Cambridge, Cambridge Institute for Medical Research, the Wellcome Trust MRC Institute of Metabolic Science and NIHR Cambridge Biomedical Research Centre, Cambridge CB2 0XY, United Kingdom
| | - Anne Jörns
- Institute of Clinical Biochemistry, Hannover Medical School, Hannover, Germany
| | - Sigurd Lenzen
- Institute of Clinical Biochemistry, Hannover Medical School, Hannover, Germany; Institute of Experimental Diabetes Research, Hannover Medical School, Hannover, Germany.
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22
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Wasserfall C, Nick HS, Campbell-Thompson M, Beachy D, Haataja L, Kusmartseva I, Posgai A, Beery M, Rhodes C, Bonifacio E, Arvan P, Atkinson M. Persistence of Pancreatic Insulin mRNA Expression and Proinsulin Protein in Type 1 Diabetes Pancreata. Cell Metab 2017; 26:568-575.e3. [PMID: 28877460 PMCID: PMC5679224 DOI: 10.1016/j.cmet.2017.08.013] [Citation(s) in RCA: 66] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/16/2017] [Revised: 05/12/2017] [Accepted: 08/09/2017] [Indexed: 01/25/2023]
Abstract
The canonical notion that type 1 diabetes (T1D) results following a complete destruction of β cells has recently been questioned as small amounts of C-peptide are detectable in patients with long-standing disease. We analyzed protein and gene expression levels for proinsulin, insulin, C-peptide, and islet amyloid polypeptide within pancreatic tissues from T1D, autoantibody positive (Ab+), and control organs. Insulin and C-peptide levels were low to undetectable in extracts from the T1D cohort; however, proinsulin and INS mRNA were detected in the majority of T1D pancreata. Interestingly, heterogeneous nuclear RNA (hnRNA) for insulin and INS-IGF2, both originating from the INS promoter, were essentially undetectable in T1D pancreata, arguing for a silent INS promoter. Expression of PCSK1, a convertase responsible for proinsulin processing, was reduced in T1D pancreata, supportive of persistent proinsulin. These data implicate the existence of β cells enriched for inefficient insulin/C-peptide production in T1D patients, potentially less susceptible to autoimmune destruction.
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Affiliation(s)
- Clive Wasserfall
- Department of Pathology, Immunology, and Laboratory Medicine, The University of Florida Diabetes Institute, Gainesville, FL, USA
| | - Harry S Nick
- Department of Neuroscience, The University of Florida Diabetes Institute, Gainesville, FL, USA
| | - Martha Campbell-Thompson
- Department of Pathology, Immunology, and Laboratory Medicine, The University of Florida Diabetes Institute, Gainesville, FL, USA
| | - Dawn Beachy
- Department of Neuroscience, The University of Florida Diabetes Institute, Gainesville, FL, USA
| | - Leena Haataja
- Department of Internal Medicine, University of Michigan Heath System Brehm Center for Diabetes Research, Ann Arbor, MI, USA
| | - Irina Kusmartseva
- Department of Pathology, Immunology, and Laboratory Medicine, The University of Florida Diabetes Institute, Gainesville, FL, USA
| | - Amanda Posgai
- Department of Pathology, Immunology, and Laboratory Medicine, The University of Florida Diabetes Institute, Gainesville, FL, USA
| | - Maria Beery
- Department of Pathology, Immunology, and Laboratory Medicine, The University of Florida Diabetes Institute, Gainesville, FL, USA
| | - Christopher Rhodes
- The Kovler Diabetes Center, Department of Medicine, The University of Chicago, Chicago, IL, USA
| | - Ezio Bonifacio
- Center for Regenerative Therapies, Dresden University of Technology, Dresden, Germany
| | - Peter Arvan
- Department of Internal Medicine, University of Michigan Heath System Brehm Center for Diabetes Research, Ann Arbor, MI, USA
| | - Mark Atkinson
- Department of Pathology, Immunology, and Laboratory Medicine, The University of Florida Diabetes Institute, Gainesville, FL, USA.
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23
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Stijnen P, Ramos-Molina B, O'Rahilly S, Creemers JWM. PCSK1 Mutations and Human Endocrinopathies: From Obesity to Gastrointestinal Disorders. Endocr Rev 2016; 37:347-71. [PMID: 27187081 DOI: 10.1210/er.2015-1117] [Citation(s) in RCA: 90] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Prohormone convertase 1/3, encoded by the PCSK1 gene, is a serine endoprotease that is involved in the processing of a variety of proneuropeptides and prohormones. Humans who are homozygous or compound heterozygous for loss-of-function mutations in PCSK1 exhibit a variable and pleiotropic syndrome consisting of some or all of the following: obesity, malabsorptive diarrhea, hypogonadotropic hypogonadism, altered thyroid and adrenal function, and impaired regulation of plasma glucose levels in association with elevated circulating proinsulin-to-insulin ratio. Recently, more common variants in the PCSK1 gene have been found to be associated with alterations in body mass index, increased circulating proinsulin levels, and defects in glucose homeostasis. This review provides an overview of the endocrinopathies and other disorders observed in prohormone convertase 1/3-deficient patients, discusses the possible biochemical basis for these manifestations of the disease, and proposes a model whereby certain missense mutations in PCSK1 may result in proteins with a dominant negative action.
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Affiliation(s)
- Pieter Stijnen
- Laboratory for Biochemical Neuroendocrinology (P.S., B.R.-M., J.W.M.C.), Department of Human Genetics, KU Leuven, Leuven 3000, Belgium; and Medical Research Council (MRC) Metabolic Diseases Unit (S.O.), Wellcome Trust-MRC Institute of Metabolic Science, National Institute for Health Research, Cambridge Biomedical Research Centre, Addenbrooke's Hospital, University of Cambridge, Cambridge CB2 0QQ, United Kingdom
| | - Bruno Ramos-Molina
- Laboratory for Biochemical Neuroendocrinology (P.S., B.R.-M., J.W.M.C.), Department of Human Genetics, KU Leuven, Leuven 3000, Belgium; and Medical Research Council (MRC) Metabolic Diseases Unit (S.O.), Wellcome Trust-MRC Institute of Metabolic Science, National Institute for Health Research, Cambridge Biomedical Research Centre, Addenbrooke's Hospital, University of Cambridge, Cambridge CB2 0QQ, United Kingdom
| | - Stephen O'Rahilly
- Laboratory for Biochemical Neuroendocrinology (P.S., B.R.-M., J.W.M.C.), Department of Human Genetics, KU Leuven, Leuven 3000, Belgium; and Medical Research Council (MRC) Metabolic Diseases Unit (S.O.), Wellcome Trust-MRC Institute of Metabolic Science, National Institute for Health Research, Cambridge Biomedical Research Centre, Addenbrooke's Hospital, University of Cambridge, Cambridge CB2 0QQ, United Kingdom
| | - John W M Creemers
- Laboratory for Biochemical Neuroendocrinology (P.S., B.R.-M., J.W.M.C.), Department of Human Genetics, KU Leuven, Leuven 3000, Belgium; and Medical Research Council (MRC) Metabolic Diseases Unit (S.O.), Wellcome Trust-MRC Institute of Metabolic Science, National Institute for Health Research, Cambridge Biomedical Research Centre, Addenbrooke's Hospital, University of Cambridge, Cambridge CB2 0QQ, United Kingdom
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24
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Ruiz-Narváez EA, Haddad SA, Rosenberg L, Palmer JR. Birth weight modifies the association between central nervous system gene variation and adult body mass index. J Hum Genet 2016; 61:193-8. [PMID: 26582267 PMCID: PMC4808432 DOI: 10.1038/jhg.2015.139] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2015] [Revised: 10/23/2015] [Accepted: 10/26/2015] [Indexed: 12/11/2022]
Abstract
Genome wide association studies have identified ~100 loci associated with body mass index (BMI). Persons with low birth weight have an increased risk of metabolic disorders. We postulate that normal mechanisms of body weight regulation are disrupted in subjects with low birth weight. The present analyses included 2215 African American women from the Black Women's Health Study, and were based on genotype data on 20 BMI-associated loci and self-reported data on birth weight, weight at age 18 and adult weight. We used general linear models to assess the association of individual single-nucleotide polymorphisms (SNPs) with BMI at age 18 and later in adulthood within strata of birth weight (above and below the median, 3200 g). Three SNPs (rs1320330 near TMEM18, rs261967 near PCSK1 and rs17817964 in FTO), and a genetic score combining these three variants, showed significant interactions with birth weight in relation to BMI. Among women with birth weight <3200 g, there was an inverse association between genetic score and BMI; beta-coefficient=-0.045 (95% confidence intervals (CI) -0.104, 0.013) for BMI at age 18, and -0.055 (95% CI -0.112, 0.002) for adult BMI. Among women with birth weight ⩾3200 g, genetic score was positively associated with BMI: beta-coefficient=0.110 (95% CI 0.051, 0.169) for BMI at age 18 (P for interaction=0.0002), and 0.112 (95% CI 0.054, 0.170) for adult BMI (P for interaction<0.0001). Because TMEM18, PCSK1 and FTO are highly expressed in the central nervous system (CNS), our results suggest that low-birth weight may disrupt mechanisms of CNS body weight regulation.
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Affiliation(s)
- Edward A. Ruiz-Narváez
- Slone Epidemiology Center at Boston University; Boston MA 02215
- Department of Epidemiology; Boston University School of Public Health; Boston MA 02118
| | - Stephen A. Haddad
- Slone Epidemiology Center at Boston University; Boston MA 02215
- Department of Epidemiology; Boston University School of Public Health; Boston MA 02118
| | - Lynn Rosenberg
- Slone Epidemiology Center at Boston University; Boston MA 02215
- Department of Epidemiology; Boston University School of Public Health; Boston MA 02118
| | - Julie R. Palmer
- Slone Epidemiology Center at Boston University; Boston MA 02215
- Department of Epidemiology; Boston University School of Public Health; Boston MA 02118
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25
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Asadi A, Bruin JE, Kieffer TJ. Characterization of Antibodies to Products of Proinsulin Processing Using Immunofluorescence Staining of Pancreas in Multiple Species. J Histochem Cytochem 2015. [PMID: 26216140 DOI: 10.1369/0022155415576541] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
The efficient processing of proinsulin into mature insulin and C-peptide is often compromised under conditions of beta cell stress, including diabetes. Impaired proinsulin processing has been challenging to examine by immunofluorescence staining in pancreas tissue because the characterization of antibodies specific for proinsulin, proinsulin intermediates, processed insulin and C-peptide has been limited. This study aimed to identify and characterize antibodies that can be used to detect products of proinsulin processing by immunofluorescence staining in pancreata from different species (mice, rats, dog, pig and human). We took advantage of several knockout mouse lines that lack either an enzyme involved in proinsulin processing or an insulin gene. Briefly, we report antibodies that are specific for several proinsulin processing products, including: a) insulin or proinsulin that has been appropriately processed at the B-C junction; b) proinsulin with a non-processed B-C junction; c) proinsulin with a non-processed A-C junction; d) rodent-specific C-peptide 1; e) rodent-specific C-peptide 2; and f) human-specific C-peptide or proinsulin. In addition, we also describe two 'pan-insulin' antibodies that react with all forms of insulin and proinsulin intermediates, regardless of the species. These antibodies are valuable tools for studying proinsulin processing by immunofluorescence staining and distinguishing between proinsulin products in different species.
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Affiliation(s)
- Ali Asadi
- Laboratory of Molecular and Cellular Medicine, Department of Cellular & Physiological Sciences, Life Sciences Institute, University of British Columbia, Vancouver, BC, Canada (AA, JEB, TJK)
| | - Jennifer E Bruin
- Laboratory of Molecular and Cellular Medicine, Department of Cellular & Physiological Sciences, Life Sciences Institute, University of British Columbia, Vancouver, BC, Canada (AA, JEB, TJK)
| | - Timothy J Kieffer
- Laboratory of Molecular and Cellular Medicine, Department of Cellular & Physiological Sciences, Life Sciences Institute, University of British Columbia, Vancouver, BC, Canada (AA, JEB, TJK),Department of Surgery, University of British Columbia, Vancouver, BC, Canada (TJK)
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26
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Somboonwong J, Traisaeng S, Saguanrungsirikul S. Moderate-intensity exercise training elevates serum and pancreatic zinc levels and pancreatic ZnT8 expression in streptozotocin-induced diabetic rats. Life Sci 2015; 139:46-51. [DOI: 10.1016/j.lfs.2015.08.008] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2015] [Revised: 07/16/2015] [Accepted: 08/01/2015] [Indexed: 01/17/2023]
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27
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Bogari NM, Rayes HH, Mostafa F, Abdel-Latif AM, Ramadan A, Al-Allaf FA, Taher MM, Fawzy A. A novel SNP in 3' UTR of INS gene: A case report of neonatal diabetes mellitus. Diabetes Res Clin Pract 2015. [PMID: 26212367 DOI: 10.1016/j.diabres.2015.06.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Neonatal diabetes mellitus (NDM) is a rare condition with a prevalence of 1 in 300,000 live births. We have found 3 known SNPs in 5'UTR and a novel SNP in 3' UTR in the INS gene. These SNPs were present in 9-month-old girl from Saudi Arabia and also present in the father and mother. The novel SNP we found is not present in 1000 Genome project or other databases. Further, the newly identified 3' UTR mutation in the INS gene may abolish the polyadenylation signal and result in severe RNA instability.
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Affiliation(s)
- Neda M Bogari
- Department of Medical Genetics, Faculty of Medicine, Umm Al-Qura University, Makkah 21955, Saudi Arabia.
| | - Husni H Rayes
- Department of Pediatrics, Maternity and Children's Hospital, Makkah 21955, Saudi Arabia
| | - Fakri Mostafa
- Department of Pediatrics, Maternity and Children's Hospital, Makkah 21955, Saudi Arabia
| | - Azza M Abdel-Latif
- Division of Human Genetics & Genome Research; Department of Molecular Genetics and Enzymology, National Research Centre, 33 Bohouth St. Dokki, Giza, Egypt
| | - Abeer Ramadan
- Division of Human Genetics & Genome Research; Department of Molecular Genetics and Enzymology, National Research Centre, 33 Bohouth St. Dokki, Giza, Egypt
| | - Faisal A Al-Allaf
- Department of Medical Genetics, Faculty of Medicine, Umm Al-Qura University, Makkah 21955, Saudi Arabia; Science and Technology Unit, Umm Al-Qura University, Makkah 21955, Saudi Arabia; Molecular Diagnostics Unit, Department of Laboratory Medicine and Blood Bank, King Abdullah Medical City, Makkah 21955, Saudi Arabia
| | - Mohiuddin M Taher
- Science and Technology Unit, Umm Al-Qura University, Makkah 21955, Saudi Arabia.
| | - Ahmed Fawzy
- Division of Human Genetics & Genome Research; Department of Molecular Genetics and Enzymology, National Research Centre, 33 Bohouth St. Dokki, Giza, Egypt.
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28
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Sun J, Cui J, He Q, Chen Z, Arvan P, Liu M. Proinsulin misfolding and endoplasmic reticulum stress during the development and progression of diabetes. Mol Aspects Med 2015; 42:105-18. [PMID: 25579745 PMCID: PMC4404191 DOI: 10.1016/j.mam.2015.01.001] [Citation(s) in RCA: 119] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2014] [Revised: 12/31/2014] [Accepted: 01/02/2015] [Indexed: 02/06/2023]
Abstract
To maintain copious insulin granule stores in the face of ongoing metabolic demand, pancreatic beta cells must produce large quantities of proinsulin, the insulin precursor. Proinsulin biosynthesis can account for up to 30-50% of total cellular protein synthesis of beta cells. This puts pressure on the beta cell secretory pathway, especially the endoplasmic reticulum (ER), where proinsulin undergoes its initial folding, including the formation of three evolutionarily conserved disulfide bonds. In normal beta cells, up to 20% of newly synthesized proinsulin may fail to reach its native conformation, suggesting that proinsulin is a misfolding-prone protein. Misfolded proinsulin molecules can either be refolded to their native structure or degraded through ER associated degradation (ERAD) and autophagy. These degraded molecules decrease proinsulin yield but do not otherwise compromise beta cell function. However, under certain pathological conditions, proinsulin misfolding increases, exceeding the genetically determined threshold of beta cells to handle the misfolded protein load. This results in accumulation of misfolded proinsulin in the ER - a causal factor leading to beta cell failure and diabetes. In patients with Mutant INS-gene induced diabetes of Youth (MIDY), increased proinsulin misfolding due to insulin gene mutations is the primary defect operating as a "first hit" to beta cells. Additionally, increased proinsulin misfolding can be secondary to an unfavorable ER folding environment due to genetic and/or environmental factors. Under these conditions, increased wild-type proinsulin misfolding becomes a "second hit" to the ER and beta cells, aggravating beta cell failure and diabetes. In this article, we describe our current understanding of the normal proinsulin folding pathway in the ER, and then review existing links between proinsulin misfolding, ER dysfunction, and beta cell failure in the development and progression of type 2, type 1, and some monogenic forms of diabetes.
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Affiliation(s)
- Jinhong Sun
- Division of Metabolism, Endocrinology & Diabetes, University of Michigan, Ann Arbor, MI 48105, USA
| | - Jingqiu Cui
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin 300052, China
| | - Qing He
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin 300052, China
| | - Zheng Chen
- School of Life Sciences, Northeast Normal University, Changchun, Jilin 130024, China
| | - Peter Arvan
- Division of Metabolism, Endocrinology & Diabetes, University of Michigan, Ann Arbor, MI 48105, USA.
| | - Ming Liu
- Division of Metabolism, Endocrinology & Diabetes, University of Michigan, Ann Arbor, MI 48105, USA; Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin 300052, China.
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29
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Zip4 mediated zinc influx stimulates insulin secretion in pancreatic beta cells. PLoS One 2015; 10:e0119136. [PMID: 25806541 PMCID: PMC4373830 DOI: 10.1371/journal.pone.0119136] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2014] [Accepted: 01/19/2015] [Indexed: 01/07/2023] Open
Abstract
Zinc has an important role in normal pancreatic beta cell physiology as it regulates gene transcription, insulin crystallization and secretion, and cell survival. Nevertheless, little is known about how zinc is transported through the plasma membrane of beta cells and which of the class of zinc influx transporters (Zip) is involved. Zip4 was previously shown to be expressed in human and mouse beta cells; however, its function there is still unknown. Therefore, the aim of this study was to define the zinc transport role of Zip4 in beta cells. To investigate this, Zip4 was over-expressed in MIN6 beta cells using a pCMV6-Zip4GFP plasmid. Organelle staining combined with confocal microscopy showed that Zip4 exhibits a widespread localization in MIN6 cells. Time-lapse zinc imaging experiments showed that Zip4 increases cytoplasmic zinc levels. This resulted in increased granular zinc content and glucose-stimulated insulin secretion. Interestingly, it is unlikely that the increased glucose stimulated insulin secretion was triggered by a modulation of mitochondrial function, as mitochondrial membrane potential remained unchanged. To define the role of Zip4 in-vivo, we generated a beta cell-specific knockout mouse model (Zip4BKO). Deletion of the Zip4 gene was confirmed in Zip4BKO islets by PCR, RT-PCR, and immuno-histochemistry. Zip4BKO mice showed slightly improved glucose homeostasis but no change in insulin secretion during an oral glucose tolerance test. While Zip4 was not found to be essential for proper glucose homeostasis and insulin secretion in vivo in mice, this study also found that Zip4 mediates increases in cytoplasmic and granular zinc pools and stimulates glucose dependant insulin secretion in-vitro.
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Rajan S, Dickson LM, Mathew E, Orr CMO, Ellenbroek JH, Philipson LH, Wicksteed B. Chronic hyperglycemia downregulates GLP-1 receptor signaling in pancreatic β-cells via protein kinase A. Mol Metab 2015; 4:265-76. [PMID: 25830090 PMCID: PMC4354925 DOI: 10.1016/j.molmet.2015.01.010] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/12/2015] [Revised: 01/21/2015] [Accepted: 01/26/2015] [Indexed: 02/07/2023] Open
Abstract
Objective Glucagon-like peptide 1 (GLP-1) enhances insulin secretion and protects β-cell mass. Diabetes therapies targeting the GLP-1 receptor (GLP-1R), expressed in numerous tissues, have diminished dose-response in patients with type 2 diabetes compared with healthy human controls. The aim of this study was to determine the mechanistic causes underlying the reduced efficacy of GLP-1R ligands. Methods Using primary mouse islets and the β-cell line MIN6, outcomes downstream of the GLP-1R were analyzed: Insulin secretion; phosphorylation of the cAMP-response element binding protein (CREB); cAMP responses. Signaling systems were studied by immunoblotting and qRT-PCR, and PKA activity was assayed. Cell surface localization of the GLP-1R was studied by confocal microscopy using a fluorescein-tagged exendin-4 and GFP-tagged GLP-1R. Results Rodent β-cells chronically exposed to high glucose had diminished responses to GLP-1R agonists including: diminished insulin secretory response; reduced phosphorylation of (CREB); impaired cAMP response, attributable to chronically increased cAMP levels. GLP-1R signaling systems were affected by hyperglycemia with increased expression of mRNAs encoding the inducible cAMP early repressor (ICER) and adenylyl cyclase 8, reduced PKA activity due to increased expression of the PKA-RIα subunit, reduced GLP-1R mRNA expression and loss of GLP-1R from the cell surface. To specifically examine the loss of GLP-1R from the plasma membrane a GLP-1R-GFP fusion protein was employed to visualize subcellular localization. Under low glucose conditions or when PKA activity was inhibited, GLP-1R-GFP was found at the plasma membrane. Conversely high glucose, expression of a constitutively active PKA subunit, or exposure to exendin-4 or forskolin led to GLP-1R-GFP internalization. Mutation of serine residue 301 of the GLP-1R abolished the glucose-dependent loss of the receptor from the plasma membrane. This was associated with a loss of an interaction between the receptor and the small ubiquitin-related modifier (SUMO), an interaction that was found to be necessary for internalization of the receptor. Conclusions These data show that glucose acting, at least in part, via PKA leads to the loss of the GLP-1R from the cell surface and an impairment of GLP-1R signaling, which may underlie the reduced clinical efficacy of GLP-1R based therapies in individuals with poorly controlled hyperglycemia.
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Affiliation(s)
- Sindhu Rajan
- Kovler Diabetes Center, The University of Chicago, USA ; Department of Medicine, Section of Adult and Pediatric Endocrinology, Diabetes and Metabolism, The University of Chicago, USA
| | - Lorna M Dickson
- Kovler Diabetes Center, The University of Chicago, USA ; Department of Medicine, Section of Adult and Pediatric Endocrinology, Diabetes and Metabolism, The University of Chicago, USA
| | - Elizabeth Mathew
- Kovler Diabetes Center, The University of Chicago, USA ; Department of Medicine, Section of Adult and Pediatric Endocrinology, Diabetes and Metabolism, The University of Chicago, USA
| | - Caitlin M O Orr
- Kovler Diabetes Center, The University of Chicago, USA ; Department of Medicine, Section of Adult and Pediatric Endocrinology, Diabetes and Metabolism, The University of Chicago, USA ; Committee on Molecular Metabolism and Nutrition, The University of Chicago, USA
| | - Johanne H Ellenbroek
- Kovler Diabetes Center, The University of Chicago, USA ; Department of Medicine, Section of Adult and Pediatric Endocrinology, Diabetes and Metabolism, The University of Chicago, USA
| | - Louis H Philipson
- Kovler Diabetes Center, The University of Chicago, USA ; Department of Medicine, Section of Adult and Pediatric Endocrinology, Diabetes and Metabolism, The University of Chicago, USA ; Committee on Molecular Metabolism and Nutrition, The University of Chicago, USA
| | - Barton Wicksteed
- Kovler Diabetes Center, The University of Chicago, USA ; Department of Medicine, Section of Adult and Pediatric Endocrinology, Diabetes and Metabolism, The University of Chicago, USA ; Committee on Molecular Metabolism and Nutrition, The University of Chicago, USA
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Aathira R, Jain V. Advances in management of type 1 diabetes mellitus. World J Diabetes 2014; 5:689-696. [PMID: 25317246 PMCID: PMC4138592 DOI: 10.4239/wjd.v5.i5.689] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/13/2014] [Revised: 06/18/2014] [Accepted: 07/17/2014] [Indexed: 02/05/2023] Open
Abstract
Treatment of type 1 diabetes mellitus has always posed a challenge to balance hyperglycemia control with hypoglycemia episodes. The quest for newer therapies is continuing and this review attempts to outline the recent developments. The insulin molecule itself has got moulded into different analogues by minor changes in its structure to ensure well controlled delivery, stable half-lives and lesser side effects. Insulin delivery systems have also consistently undergone advances from subcutaneous injections to continuous infusion to trials of inhalational delivery. Continuous glucose monitoring systems are also becoming more accurate and user friendly. Smartphones have also made their entry into therapy of diabetes by integrating blood glucose levels and food intake with calculated adequate insulin required. Artificial pancreas has enabled to a certain extent to close the loop between blood glucose level and insulin delivery with devices armed with meal and exercise announcements, dual hormone delivery and pramlintide infusion. Islet, pancreas-kidney and stem cells transplants are also being attempted though complete success is still a far way off. Incorporating insulin gene and secretary apparatus is another ambitious leap to achieve insulin independence though the search for the ideal vector and target cell is still continuing. Finally to stand up to the statement, prevention is better than cure, immunological methods are being investigated to be used as vaccine to prevent the onset of diabetes mellitus.
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Wang L, Liu Y, Yang J, Zhao H, Ke J, Tian Q, Zhang L, Wen J, Wei R, Hong T. GLP-1 analog liraglutide enhances proinsulin processing in pancreatic β-cells via a PKA-dependent pathway. Endocrinology 2014; 155:3817-28. [PMID: 25051441 DOI: 10.1210/en.2014-1218] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Hyperproinsulinemia has gained increasing attention in the development of type 2 diabetes. Clinical studies have demonstrated that glucagon-like peptide-1 (GLP-1)-based therapies significantly decrease plasma proinsulin/insulin ratio in patients with type 2 diabetes. However, the underlying mechanism remains unclear. Prohormone convertase (PC)-1/3 and PC2 are primarily responsible for processing proinsulin to insulin in pancreatic β-cells. We have recently reported that Pax6 mutation down-regulated PC1/3 and PC2 expression, resulting in defective proinsulin processing in Pax6 heterozygous mutant (Pax6(m/+)) mice. In this study, we investigated whether and how liraglutide, a novel GLP-1 analog, modulated proinsulin processing. Our results showed that liraglutide significantly up-regulated PC1/3 expression and decreased the proinsulin to insulin ratio in both Pax6(m/+) and db/db diabetic mice. In the cultured mouse pancreatic β-cell line, Min6, liraglutide stimulated PC1/3 and PC2 expression and lowered the proinsulin to insulin ratio in a dose- and time-dependent manner. Moreover, the beneficial effects of liraglutide on PC1/3 and PC2 expression and proinsulin processing were dependent on the GLP-1 receptor-mediated cAMP/protein kinase A signaling pathway. The same mechanism was recapitulated in isolated mouse islets. In conclusion, liraglutide enhanced PC1/3- and PC2-dependent proinsulin processing in pancreatic β-cells through the activation of the GLP-1 receptor/cAMP/protein kinase A signaling pathway. Our study provides a new mechanism for improvement of pancreatic β-cell function by the GLP-1-based therapy.
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Affiliation(s)
- Liang Wang
- Department of Endocrinology and Metabolism (L.W., Y.L., J.Y., H.Z., J.K., Q.T., L.Z., R.W., T.H.), Peking University Third Hospital, and Peking University Stem Cell Research Center (J.W., T.H.), Peking University Health Science Center, Beijing 100191, China
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Chen Y, Feng R, Wang H, Wei R, Yang J, Wang L, Wang H, Zhang L, Hong TP, Wen J. High-fat diet induces early-onset diabetes in heterozygous Pax6 mutant mice. Diabetes Metab Res Rev 2014; 30:467-75. [PMID: 24925705 DOI: 10.1002/dmrr.2572] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/24/2013] [Revised: 05/13/2014] [Accepted: 06/04/2014] [Indexed: 11/06/2022]
Abstract
BACKGROUND Type 2 diabetes is caused by interactions between genetic and environmental factors. Our previous studies reported that paired box 6 mutation heterozygosity (Pax6(m/+)) led to defective proinsulin processing and subsequent abnormal glucose metabolism in mice at 6 months of age. However, high-fat diet exposure could be an important incentive for diabetes development. In this study, we aimed to develop a novel diabetic model imitating human type 2 diabetes by exposing Pax6(m/+) mice to high-fat diet and to explore the underlying mechanism of diabetes in this model. METHODS Over 300 Pax6(m/+) and wild-type male weanling mice were randomly divided into two groups and were fed an high-fat diet or chow diet for 6-10 weeks. Blood glucose and glucose tolerance levels were monitored during this period. Body weights, visceral adipose weights, blood lipid profiles and insulin sensitivity (determined with an insulin tolerance test) were used to evaluate obesity and insulin resistance. Proinsulin processing and insulin secretion levels were used to evaluate pancreatic β cell function. RESULTS After 6 weeks of high-fat diet exposure, only the Pax6(m/+) mice showed dramatic postloading hyperglycaemia. These mice exhibited significant high-fat diet-induced visceral obesity and insulin resistance and displayed defective prohormone convertase 1/3 production, an increased proinsulin:total insulin ratio and impaired early-phase insulin secretion, because of the Pax6 mutation. Hyperglycaemia worsened progressively over time with the high-fat diet, and most Pax6(m/+) mice on high-fat diet developed diabetes or impaired glucose tolerance after 10 weeks. Furthermore, high-fat diet withdrawal partly improved blood glucose levels in the diabetic mice. CONCLUSIONS By combining the Pax6(m/+) genetic background with an high-fat diet environment, we developed a novel diabetic model to mimic human type 2 diabetes. This model is characterized by impaired insulin secretion, caused by the Pax6 mutation, and high-fat diet-induced insulin resistance and therefore provides an ideal tool for research on type 2 diabetes pathogenesis and therapies.
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MESH Headings
- Animals
- Diabetes Mellitus, Type 2/blood
- Diabetes Mellitus, Type 2/complications
- Diabetes Mellitus, Type 2/etiology
- Diabetes Mellitus, Type 2/metabolism
- Diet, High-Fat/adverse effects
- Eye Proteins/genetics
- Eye Proteins/metabolism
- Glucagon-Like Peptide 1/blood
- Glucagon-Like Peptide 1/metabolism
- Heterozygote
- Homeodomain Proteins/genetics
- Homeodomain Proteins/metabolism
- Insulin/blood
- Insulin/metabolism
- Insulin Resistance
- Insulin Secretion
- Islets of Langerhans/metabolism
- Male
- Mice, Inbred C57BL
- Mice, Mutant Strains
- Mutation
- Obesity, Abdominal/complications
- Obesity, Abdominal/etiology
- Obesity, Abdominal/physiopathology
- PAX6 Transcription Factor
- Paired Box Transcription Factors/genetics
- Paired Box Transcription Factors/metabolism
- Prediabetic State/blood
- Prediabetic State/complications
- Prediabetic State/etiology
- Prediabetic State/metabolism
- Proinsulin/blood
- Proinsulin/metabolism
- Proprotein Convertase 1/metabolism
- Random Allocation
- Repressor Proteins/genetics
- Repressor Proteins/metabolism
- Weaning
- Weight Gain
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Affiliation(s)
- Yuanyuan Chen
- Department of Endocrinology and Metabolism, Peking University Third Hospital, Peking University Stem Cell Research Centre, Peking University Health Science Center, Beijing, China; Jiangsu Province Key Lab of Human Functional Genomics, Department of Biochemistry and Molecular Biology, Nanjing Medical University, Nanjing, China
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Mehmeti I, Lortz S, Elsner M, Lenzen S. Peroxiredoxin 4 improves insulin biosynthesis and glucose-induced insulin secretion in insulin-secreting INS-1E cells. J Biol Chem 2014; 289:26904-26913. [PMID: 25122762 DOI: 10.1074/jbc.m114.568329] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Oxidative folding of (pro)insulin is crucial for its assembly and biological function. This process takes place in the endoplasmic reticulum (ER) and is accomplished by protein disulfide isomerase and ER oxidoreductin 1β, generating stoichiometric amounts of hydrogen peroxide (H2O2) as byproduct. During insulin resistance in the prediabetic state, increased insulin biosynthesis can overwhelm the ER antioxidative and folding capacity, causing an imbalance in the ER redox homeostasis and oxidative stress. Peroxiredoxin 4 (Prdx4), an ER-specific antioxidative peroxidase can utilize luminal H2O2 as driving force for reoxidizing protein disulfide isomerase family members, thus efficiently contributing to disulfide bond formation. Here, we examined the functional significance of Prdx4 on β-cell function with emphasis on insulin content and secretion during stimulation with nutrient secretagogues. Overexpression of Prdx4 in glucose-responsive insulin-secreting INS-1E cells significantly metabolized luminal H2O2 and improved the glucose-induced insulin secretion, which was accompanied by the enhanced proinsulin mRNA transcription and insulin content. This β-cell beneficial effect was also observed upon stimulation with the nutrient insulin secretagogue combination of leucine plus glutamine, indicating that the effect is not restricted to glucose. However, knockdown of Prdx4 had no impact on H2O2 metabolism or β-cell function due to the fact that Prdx4 expression is negligibly low in pancreatic β-cells. Moreover, we provide evidence that the constitutively low expression of Prdx4 is highly susceptible to hyperoxidation in the presence of high glucose. Overall, these data suggest an important role of Prdx4 in maintaining insulin levels and improving the ER folding capacity also under conditions of a high insulin requirement.
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Affiliation(s)
- Ilir Mehmeti
- Institute of Clinical Biochemistry, Hannover Medical School, 30623 Hannover, Germany
| | - Stephan Lortz
- Institute of Clinical Biochemistry, Hannover Medical School, 30623 Hannover, Germany
| | - Matthias Elsner
- Institute of Clinical Biochemistry, Hannover Medical School, 30623 Hannover, Germany
| | - Sigurd Lenzen
- Institute of Clinical Biochemistry, Hannover Medical School, 30623 Hannover, Germany.
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Tros F, Meirhaeghe A, Hadjadj S, Amouyel P, Bougnères P, Fradin D. Hypomethylation of the promoter of the catalytic subunit of protein phosphatase 2A in response to hyperglycemia. Physiol Rep 2014; 2:2/7/e12076. [PMID: 25347859 PMCID: PMC4187575 DOI: 10.14814/phy2.12076] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
In order to identify epigenetic mechanisms through which hyperglycemia can affect gene expression durably in β cells, we screened DNA methylation changes induced by high glucose concentrations (25 mmol/L) in the BTC3 murine cell line, using an epigenome‐wide approach. Exposure of BTC3 cells to high glucose modified the expression of 1612 transcripts while inducing significant methylation changes in 173 regions. Among these 173 glucose‐sensitive differentially methylated regions (DMRs), 14 were associated with changes in gene expression, suggesting an epigenetic effect of high glucose on gene transcription at these loci. Among these 14 DMRs, we selected for further study Pp2ac, a gene previously suspected to play a role in β‐cell physiology and type 2 diabetes. Using RT‐qPCR and bisulfite pyrosequencing, we confirmed our previous observations in BTC3 cells and found that this gene was significantly demethylated in the whole blood cells (WBCs) of type 2 diabetic patients compared to controls. In order to identify epigenetic mechanisms through which hyperglycemia can affect gene expression durably in β cells, we screened DNA methylation changes induced by high glucose concentration in the BTC3 murine cell line. We identified one interesting gene, PP2AC, and confirmed it in type 2 diabetic patients.
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Affiliation(s)
- Fabiola Tros
- INSERM U986, Bicêtre Hospital, Paris Sud University, Le Kremlin-Bicêtre, France UMR1002, Paris, France
| | - Aline Meirhaeghe
- INSERM, U744, Lille, France Institut Pasteur de Lille, Université Lille Nord de France, Lille, France UDSL, Lille, France
| | - Samy Hadjadj
- Department of Diabetology, Poitiers Hospital, INSERM U927, INSERM CIC 802, Université de Poitiers, UFR Médecine Pharmacie, Poitiers, France
| | - Philippe Amouyel
- INSERM, U744, Lille, France Institut Pasteur de Lille, Université Lille Nord de France, Lille, France UDSL, Lille, France
| | - Pierre Bougnères
- INSERM U986, Bicêtre Hospital, Paris Sud University, Le Kremlin-Bicêtre, France Department of Pediatric Endocrinology, Bicêtre Hospital, Paris Sud University, Le Kremlin-Bicêtre, France
| | - Delphine Fradin
- INSERM U986, Bicêtre Hospital, Paris Sud University, Le Kremlin-Bicêtre, France
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36
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Deregulation of pancreas-specific oxidoreductin ERO1β in the pathogenesis of diabetes mellitus. Mol Cell Biol 2014; 34:1290-9. [PMID: 24469402 DOI: 10.1128/mcb.01647-13] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
A growing body of evidence has underlined the significance of endoplasmic reticulum (ER) stress in the pathogenesis of diabetes mellitus. ER oxidoreductin 1β (ERO1β) is a pancreas-specific disulfide oxidase that is known to be upregulated in response to ER stress and to promote protein folding in pancreatic β cells. It has recently been demonstrated that ERO1β promotes insulin biogenesis in β cells and thus contributes to physiological glucose homeostasis, though it is unknown if ERO1β is involved in the pathogenesis of diabetes mellitus. Here we show that in diabetic model mice, ERO1β expression is paradoxically decreased in β cells despite the indications of increased ER stress. However, overexpression of ERO1β in β cells led to the upregulation of unfolded protein response genes and markedly enlarged ER lumens, indicating that ERO1β overexpression caused ER stress in the β cells. Insulin contents were decreased in the β cells that overexpressed ERO1β, leading to impaired insulin secretion in response to glucose stimulation. These data indicate the importance of the fine-tuning of the ER redox state, the disturbance of which would compromise the function of β cells in insulin synthesis and thus contribute to the pathogenesis of diabetes mellitus.
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37
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Regulation of β-cell function by RNA-binding proteins. Mol Metab 2013; 2:348-55. [PMID: 24327951 DOI: 10.1016/j.molmet.2013.09.003] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/30/2013] [Revised: 09/15/2013] [Accepted: 09/16/2013] [Indexed: 02/05/2023] Open
Abstract
β-cells of the pancreatic islets are highly specialized and high-throughput units for the production of insulin, the key hormone for maintenance of glucose homeostasis. Elevation of extracellular glucose and/or GLP-1 levels triggers a rapid upregulation of insulin biosynthesis through the activation of post-transcriptional mechanisms. RNA-binding proteins are emerging as key factors in the regulation of these mechanisms as well as in other aspects of β-cell function and glucose homeostasis at large, and thus may be implicated in the pathogenesis of diabetes. Here we review current research in the field, with a major emphasis on RNA-binding proteins that control biosynthesis of insulin and other components of the insulin secretory granules by modulating the stability and translation of their mRNAs.
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Flamment M, Foufelle F. Le stress du réticulum endoplasmique : de la physiologie à la pathogenèse du diabète de type 2. Med Sci (Paris) 2013; 29:756-64. [DOI: 10.1051/medsci/2013298015] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
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Jellyman JK, Allen VL, Holdstock NB, Fowden AL. Glucocorticoid overexposure in neonatal life alters pancreatic beta-cell function in newborn foals1. J Anim Sci 2013; 91:104-10. [DOI: 10.2527/jas.2012-5475] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Affiliation(s)
- J. K. Jellyman
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge CB2 3EG, UK
| | - V. L. Allen
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge CB2 3EG, UK
| | - N. B. Holdstock
- Department of Clinical Veterinary Medicine, University of Cambridge, Cambridge CB2 3EG, UK
| | - A. L. Fowden
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge CB2 3EG, UK
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40
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Shen N, Huan Y, Shen ZF. Berberine inhibits mouse insulin gene promoter through activation of AMP activated protein kinase and may exert beneficial effect on pancreatic β-cell. Eur J Pharmacol 2012; 694:120-6. [DOI: 10.1016/j.ejphar.2012.07.052] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2012] [Revised: 07/07/2012] [Accepted: 07/11/2012] [Indexed: 11/15/2022]
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41
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Preferential release of newly synthesized insulin assessed by a multi-label reporter system using pancreatic β-cell line MIN6. PLoS One 2012; 7:e47921. [PMID: 23133529 PMCID: PMC3485036 DOI: 10.1371/journal.pone.0047921] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2011] [Accepted: 09/21/2012] [Indexed: 11/19/2022] Open
Abstract
Newly synthesized hormones have been suggested to be preferentially secreted by various neuroendocrine cells. This observation indicates that there is a distinct population of secretory granules containing new and old hormones. Recent development of fluorescent timer proteins used in bovine adrenal chromaffin cells revealed that secretory vesicles segregate into distinct age-dependent populations. Here, we verify the preferential release of newly synthesized insulin in the pancreatic β-cell line, MIN6, using a combination of multi-labeling reporter systems with both fluorescent and biochemical procedures. This system allows hormones or granules of any age to be labeled, in contrast to the timer proteins, which require fluorescence shift time. Pulse-chase labeling with different color probes distinguishes insulin secretory granules by age, with younger granules having a predominantly intracellular localization rather than at the cell periphery.
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Polymorphism rs11085226 in the gene encoding polypyrimidine tract-binding protein 1 negatively affects glucose-stimulated insulin secretion. PLoS One 2012; 7:e46154. [PMID: 23077502 PMCID: PMC3471934 DOI: 10.1371/journal.pone.0046154] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2012] [Accepted: 08/28/2012] [Indexed: 11/19/2022] Open
Abstract
OBJECTIVE Polypyrimidine tract-binding protein 1 (PTBP1) promotes stability and translation of mRNAs coding for insulin secretion granule proteins and thereby plays a role in β-cells function. We studied whether common genetic variations within the PTBP1 locus influence insulin secretion, and/or proinsulin conversion. METHODS We genotyped 1,502 healthy German subjects for four tagging single nucleotide polymorphisms (SNPs) within the PTBP1 locus (rs351974, rs11085226, rs736926, and rs123698) covering 100% of genetic variation with an r(2)≥0.8. The subjects were metabolically characterized by an oral glucose tolerance test with insulin, proinsulin, and C-peptide measurements. A subgroup of 320 subjects also underwent an IVGTT. RESULTS PTBP1 SNP rs11085226 was nominally associated with lower insulinogenic index and lower cleared insulin response in the OGTT (p≤0.04). The other tested SNPs did not show any association with the analyzed OGTT-derived secretion parameters. In the IVGTT subgroup, SNP rs11085226 was accordingly associated with lower insulin levels within the first ten minutes following glucose injection (p = 0.0103). Furthermore, SNP rs351974 was associated with insulin levels in the IVGTT (p = 0.0108). Upon interrogation of MAGIC HOMA-B data, our rs11085226 result was replicated (MAGIC p = 0.018), but the rs351974 was not. CONCLUSIONS We conclude that common genetic variation in PTBP1 influences glucose-stimulated insulin secretion. This underlines the importance of PTBP1 for beta cell function in vivo.
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Impairment of Proinsulin Processing in β-Cells Exposed to Saturated Free Fatty Acid Is Dependent on Uncoupling Protein-2 Expression. Can J Diabetes 2012. [DOI: 10.1016/j.jcjd.2012.06.007] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Lee EK, Kim W, Tominaga K, Martindale JL, Yang X, Subaran SS, Carlson OD, Mercken EM, Kulkarni RN, Akamatsu W, Okano H, Perrone-Bizzozero NI, de Cabo R, Egan JM, Gorospe M. RNA-binding protein HuD controls insulin translation. Mol Cell 2012; 45:826-35. [PMID: 22387028 PMCID: PMC3319250 DOI: 10.1016/j.molcel.2012.01.016] [Citation(s) in RCA: 82] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2011] [Revised: 11/21/2011] [Accepted: 01/03/2012] [Indexed: 11/18/2022]
Abstract
Although expression of the mammalian RNA-binding protein HuD was considered to be restricted to neurons, we report that HuD is present in pancreatic β cells, where its levels are controlled by the insulin receptor pathway. We found that HuD associated with a 22-nucleotide segment of the 5' untranslated region (UTR) of preproinsulin (Ins2) mRNA. Modulating HuD abundance did not alter Ins2 mRNA levels, but HuD overexpression decreased Ins2 mRNA translation and insulin production, and conversely, HuD silencing enhanced Ins2 mRNA translation and insulin production. Following treatment with glucose, HuD rapidly dissociated from Ins2 mRNA and enabled insulin biosynthesis. Importantly, HuD-knockout mice displayed higher insulin levels in pancreatic islets, while HuD-overexpressing mice exhibited lower insulin levels in islets and in plasma. In sum, our results identify HuD as a pivotal regulator of insulin translation in pancreatic β cells.
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Affiliation(s)
- Eun Kyung Lee
- Laboratory of Molecular Biology and Immunology, National Institute on Aging-Intramural Research Program, NIH, Baltimore, MD 21224, USA
- Department of Biochemistry, College of Medicine, The Catholic University of Korea, Seoul 137-701, South Korea
| | - Wook Kim
- Laboratory of Clinical Investigation, National Institute on Aging-Intramural Research Program, NIH, Baltimore, MD 21224, USA
| | - Kumiko Tominaga
- Laboratory of Molecular Biology and Immunology, National Institute on Aging-Intramural Research Program, NIH, Baltimore, MD 21224, USA
| | - Jennifer L. Martindale
- Laboratory of Molecular Biology and Immunology, National Institute on Aging-Intramural Research Program, NIH, Baltimore, MD 21224, USA
| | - Xiaoling Yang
- Laboratory of Molecular Biology and Immunology, National Institute on Aging-Intramural Research Program, NIH, Baltimore, MD 21224, USA
| | - Sarah S. Subaran
- Laboratory of Clinical Investigation, National Institute on Aging-Intramural Research Program, NIH, Baltimore, MD 21224, USA
| | - Olga D. Carlson
- Laboratory of Clinical Investigation, National Institute on Aging-Intramural Research Program, NIH, Baltimore, MD 21224, USA
| | - Evi M. Mercken
- Laboratory of Experimental Gerontology, National Institute on Aging-Intramural Research Program, NIH, Baltimore, MD 21224, USA
| | - Rohit N. Kulkarni
- Department of Islet Cell Biology and Regenerative Medicine, Joslin Diabetes Center and Department of Medicine, Harvard Medical School, Boston, MA 02215, USA
| | - Wado Akamatsu
- Department of Physiology, Graduate School of Medicine, Keio University, Shinjuku, Tokyo 160-8582, Japan
| | - Hideyuki Okano
- Department of Physiology, Graduate School of Medicine, Keio University, Shinjuku, Tokyo 160-8582, Japan
| | - Nora I. Perrone-Bizzozero
- Department of Neurosciences, School of Medicine, University of New Mexico, Albuquerque, NM 87131, USA
| | - Rafael de Cabo
- Laboratory of Experimental Gerontology, National Institute on Aging-Intramural Research Program, NIH, Baltimore, MD 21224, USA
| | - Josephine M. Egan
- Laboratory of Clinical Investigation, National Institute on Aging-Intramural Research Program, NIH, Baltimore, MD 21224, USA
| | - Myriam Gorospe
- Laboratory of Molecular Biology and Immunology, National Institute on Aging-Intramural Research Program, NIH, Baltimore, MD 21224, USA
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Abstract
Given the functional importance of the endoplasmic reticulum (ER), an organelle that performs folding, modification, and trafficking of secretory and membrane proteins to the Golgi compartment, the maintenance of ER homeostasis in insulin-secreting β-cells is very important. When ER homeostasis is disrupted, the ER generates adaptive signaling pathways, called the unfolded protein response (UPR), to maintain homeostasis of this organelle. However, if homeostasis fails to be restored, the ER initiates death signaling pathways. New observations suggest that both chronic hyperglycemia and hyperlipidemia, known as important causative factors of type 2 diabetes (T2D), disrupt ER homeostasis to induce unresolvable UPR activation and β-cell death. This review examines how the UPR pathways, induced by high glucose and free fatty acids (FFAs), interact to disrupt ER function and cause β-cell dysfunction and death.
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Affiliation(s)
- Sung Hoon Back
- School of Biological Sciences, University of Ulsan, Ulsan, Republic of Korea 680-749
| | - Randal J. Kaufman
- Degenerative Disease Research Program, Neuroscience, Aging, and Stem Cell Research Center, Sanford Burnham Medical Research Institute, La Jolla, California 92037
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Kalis M, Bolmeson C, Esguerra JLS, Gupta S, Edlund A, Tormo-Badia N, Speidel D, Holmberg D, Mayans S, Khoo NKS, Wendt A, Eliasson L, Cilio CM. Beta-cell specific deletion of Dicer1 leads to defective insulin secretion and diabetes mellitus. PLoS One 2011; 6:e29166. [PMID: 22216196 PMCID: PMC3246465 DOI: 10.1371/journal.pone.0029166] [Citation(s) in RCA: 102] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2011] [Accepted: 11/22/2011] [Indexed: 01/26/2023] Open
Abstract
Mature microRNAs (miRNAs), derived through cleavage of pre-miRNAs by the Dicer1 enzyme, regulate protein expression in many cell-types including cells in the pancreatic islets of Langerhans. To investigate the importance of miRNAs in mouse insulin secreting β-cells, we have generated mice with a β-cells specific disruption of the Dicer1 gene using the Cre-lox system controlled by the rat insulin promoter (RIP). In contrast to their normoglycaemic control littermates (RIP-Cre+/− Dicer1Δ/wt), RIP-Cre+/−Dicer1flox/flox mice (RIP-Cre Dicer1Δ/Δ) developed progressive hyperglycaemia and full-blown diabetes mellitus in adulthood that recapitulated the natural history of the spontaneous disease in mice. Reduced insulin gene expression and concomitant reduced insulin secretion preceded the hyperglycaemic state and diabetes development. Immunohistochemical, flow cytometric and ultrastructural analyses revealed altered islet morphology, marked decreased β-cell mass, reduced numbers of granules within the β-cells and reduced granule docking in adult RIP-Cre Dicer1Δ/Δ mice. β-cell specific Dicer1 deletion did not appear to disrupt fetal and neonatal β-cell development as 2-week old RIP-Cre Dicer1Δ/Δ mice showed ultrastructurally normal β-cells and intact insulin secretion. In conclusion, we have demonstrated that a β-cell specific disruption of the miRNAs network, although allowing for apparently normal β-cell development, leads to progressive impairment of insulin secretion, glucose homeostasis and diabetes development.
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Affiliation(s)
- Martins Kalis
- Cellular Autoimmunity Unit, Lund University Diabetes Center, Department of Clinical Sciences, Lund University, Malmö University Hospital, Malmö, Sweden
| | - Caroline Bolmeson
- Cellular Autoimmunity Unit, Lund University Diabetes Center, Department of Clinical Sciences, Lund University, Malmö University Hospital, Malmö, Sweden
| | - Jonathan L. S. Esguerra
- Islet Cell Exocytosis, Lund University Diabetes Center, Department of Clinical Sciences, Lund University, Malmö University Hospital, Malmö, Sweden
| | - Shashank Gupta
- Department of Disease Biology, Faculty of Life Science, Copenhagen University, Copenhagen, Denmark
| | - Anna Edlund
- Islet Cell Exocytosis, Lund University Diabetes Center, Department of Clinical Sciences, Lund University, Malmö University Hospital, Malmö, Sweden
| | - Neivis Tormo-Badia
- Cellular Autoimmunity Unit, Lund University Diabetes Center, Department of Clinical Sciences, Lund University, Malmö University Hospital, Malmö, Sweden
| | - Dina Speidel
- Islet Cell Exocytosis, Lund University Diabetes Center, Department of Clinical Sciences, Lund University, Malmö University Hospital, Malmö, Sweden
| | - Dan Holmberg
- Department of Medical Genetics, Umeå University, Umeå, Sweden
- Department of Disease Biology, Faculty of Life Science, Copenhagen University, Copenhagen, Denmark
| | - Sofia Mayans
- Department of Medical Genetics, Umeå University, Umeå, Sweden
- Department of Disease Biology, Faculty of Life Science, Copenhagen University, Copenhagen, Denmark
| | - Nelson K. S. Khoo
- Cellular Autoimmunity Unit, Lund University Diabetes Center, Department of Clinical Sciences, Lund University, Malmö University Hospital, Malmö, Sweden
| | - Anna Wendt
- Islet Cell Exocytosis, Lund University Diabetes Center, Department of Clinical Sciences, Lund University, Malmö University Hospital, Malmö, Sweden
| | - Lena Eliasson
- Islet Cell Exocytosis, Lund University Diabetes Center, Department of Clinical Sciences, Lund University, Malmö University Hospital, Malmö, Sweden
- * E-mail: (LE); (CC)
| | - Corrado M. Cilio
- Cellular Autoimmunity Unit, Lund University Diabetes Center, Department of Clinical Sciences, Lund University, Malmö University Hospital, Malmö, Sweden
- * E-mail: (LE); (CC)
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47
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A small molecule differentiation inducer increases insulin production by pancreatic β cells. Proc Natl Acad Sci U S A 2011; 108:20713-8. [PMID: 22143803 DOI: 10.1073/pnas.1118526109] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
New drugs for preserving and restoring pancreatic β-cell function are critically needed for the worldwide epidemic of type 2 diabetes and the cure for type 1 diabetes. We previously identified a family of neurogenic 3,5-disubstituted isoxazoles (Isx) that increased expression of neurogenic differentiation 1 (NeuroD1, also known as BETA2); this transcription factor functions in neuronal and pancreatic β-cell differentiation and is essential for insulin gene transcription. Here, we probed effects of Isx on human cadaveric islets and MIN6 pancreatic β cells. Isx increased the expression and secretion of insulin in islets that made little insulin after prolonged ex vivo culture and increased expression of neurogenic differentiation 1 and other regulators of islet differentiation and insulin gene transcription. Within the first few hours of exposure, Isx caused biphasic activation of ERK1/2 and increased bulk histone acetylation. Although there was little effect on histone deacetylase activity, Isx increased histone acetyl transferase activity in nuclear extracts. Reconstitution assays indicated that Isx increased the activity of the histone acetyl transferase p300 through an ERK1/2-dependent mechanism. In summary, we have identified a small molecule with antidiabetic activity, providing a tool for exploring islet function and a possible lead for therapeutic intervention in diabetes.
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48
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Substrate-favored lysosomal and proteasomal pathways participate in the normal balance control of insulin precursor maturation and disposal in β-cells. PLoS One 2011; 6:e27647. [PMID: 22102916 PMCID: PMC3213186 DOI: 10.1371/journal.pone.0027647] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2011] [Accepted: 10/21/2011] [Indexed: 11/19/2022] Open
Abstract
Our recent studies have uncovered that aggregation-prone proinsulin preserves a low relative folding rate and maintains a homeostatic balance of natively and non-natively folded states (i.e., proinsulin homeostasis, PIHO) in β-cells as a result of the integration of maturation and disposal processes. Control of precursor maturation and disposal is thus an early regulative mechanism in the insulin production of β-cells. Herein, we show pathways involved in the disposal of endogenous proinsulin at the early secretory pathway. We conducted metabolic-labeling, immunoblotting, and immunohistochemistry studies to examine the effects of selective proteasome and lysosome or autophagy inhibitors on the kinetics of proinsulin and control proteins in various post-translational courses. Our metabolic-labeling studies found that the main lysosomal and ancillary proteasomal pathways participate in the heavy clearance of insulin precursor in mouse islets/β-cells cultured at the mimic physiological glucose concentrations. Further immunoblotting and immunohistochemistry studies in cloned β-cells validated that among secretory proteins, insulin precursor is heavily and preferentially removed. The rapid disposal of a large amount of insulin precursor after translation is achieved mainly through lysosomal autophagy and the subsequent basal disposals are carried out by both lysosomal and proteasomal pathways within a 30 to 60-minute post-translational process. The findings provide the first clear demonstration that lysosomal and proteasomal pathways both play roles in the normal maintenance of PIHO for insulin production, and defined the physiological participation of lysosomal autophagy in the protein quality control at the early secretory pathway of pancreatic β-cells.
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Pallayova M, Lazurova I, Donic V. Hypoxic damage to pancreatic beta cells--the hidden link between sleep apnea and diabetes. Med Hypotheses 2011; 77:930-4. [PMID: 21899957 DOI: 10.1016/j.mehy.2011.08.016] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2011] [Accepted: 08/12/2011] [Indexed: 11/17/2022]
Abstract
Despite a large body of epidemiologic and clinical evidence suggesting that sleep disordered breathing is an independent risk factor for development of type 2 diabetes (T2DM), the underlying pathogenesis of altered glucose metabolism in sleep apnea remains to be unraveled. While previous studies have proposed some causal pathways linking sleep apnea with T2DM through increased insulin resistance and deterioration in insulin sensitivity, there has been a particular lack of research into sleep apnea-related alterations in pancreatic beta-cell function. Drawing upon our previous observation that sleep apnea is independently associated with an increased basal pancreatic beta-cell function in adults with normal glucose metabolism, the idea presented here suggests that sleep apnea imposes an excessive demand for insulin secretion, which may lead to progressive pancreatic beta-cell failure in high-risk individuals. Specifically, we hypothesize that in addition to diabetogenic effects of acute hypoxic activation of the sympathetic nervous system, the chronic intermittent hypoxemia represses the expression of key genes regulating biosynthesis of pancreatic proinsulin convertases with a resultant progressive decrease in their catalytic activity. The long-term hypoxic damage to pancreatic beta-cells may thus contribute to progression of glucose dysregulation in persons with untreated sleep apnea over time. Strategies to prevent and decrease the high prevalence and associated morbidity of T2DM are critically needed. The ideas and hypotheses presented here address the unexplored pathophysiological mechanisms underlying the potential causal link between sleep apnea and T2DM. Future hypotheses-testing will seek to delineate the role of sleep apnea in the development of T2DM, probe the underlying molecular mechanisms for pancreatic beta-cell dysfunction in sleep apnea, and obtain information on clinical, epidemiologic, and other factors responsible for protecting individuals from alterations in insulin-glucose homeostasis. These results could further be utilized in testing genetic susceptibilities and various therapy modalities to prevent pancreatic beta-cell dysfunction and maintain normal glucose status in persons with sleep apnea in the long term.
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Affiliation(s)
- Maria Pallayova
- Department of Physiology and Sleep Laboratory, School of Medicine, P.J. Safarik University, Kosice, Slovakia.
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50
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Fonseca SG, Gromada J, Urano F. Endoplasmic reticulum stress and pancreatic β-cell death. Trends Endocrinol Metab 2011; 22:266-74. [PMID: 21458293 PMCID: PMC3130122 DOI: 10.1016/j.tem.2011.02.008] [Citation(s) in RCA: 194] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/16/2010] [Revised: 01/31/2011] [Accepted: 02/23/2011] [Indexed: 12/12/2022]
Abstract
In pancreatic β-cells, the endoplasmic reticulum (ER) is an important cellular compartment for insulin biosynthesis, which accounts for half of the total protein production in these cells. Protein flux through the ER must be carefully monitored to prevent dysregulation of ER homeostasis and stress. ER stress elicits a signaling cascade known as the unfolded protein response (UPR), which influences both life and death decisions in cells. β-cell loss is a pathological component of both type 1 and type 2 diabetes, and recent findings suggest that ER stress is involved. In this review, we address the transition from the physiological ER stress response to the pathological response, and explore the mechanisms of ER stress-mediated β-cell loss during the progression of diabetes.
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Affiliation(s)
- Sonya G. Fonseca
- Cardiovascular and Metabolism Disease Area, Novartis Institutes for BioMedical Research, Cambridge, MA, USA
| | - Jesper Gromada
- Cardiovascular and Metabolism Disease Area, Novartis Institutes for BioMedical Research, Cambridge, MA, USA
| | - Fumihiko Urano
- Program in Gene Function and Expression, University of Massachusetts Medical School, Worcester, MA 01605, U.S.A
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA 01605, U.S.A
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