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Lu S, Liang S, Wu Y, Liu J, Lin L, Huang G, Ning H. Mannose phosphate isomerase gene mutation leads to a congenital disorder of glycosylation: A rare case report and literature review. Front Pediatr 2023; 11:1150367. [PMID: 37124179 PMCID: PMC10130505 DOI: 10.3389/fped.2023.1150367] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/24/2023] [Accepted: 03/13/2023] [Indexed: 05/02/2023] Open
Abstract
We report the case of a 2-year-old girl who was diagnosed with Mannose-6-phosphate isomerase-congenital disorder of glycosylation (MPI-CDG) and provide a review of the relevant literature. The young girl presented with recurrent unexplained diarrhea, vomiting, hypoproteinemia, and elevated liver transaminases. Whole-exome sequencing revealed that the patient had compound heterozygous mutations in the MPI gene (NM_0024). An exon 4 (c.455G > T, p.R152l) mutation was inherited from the mother and an exon 7 (c.884G > A, p.R295H) mutation from the father. One week after the start of mannose treatment, the vomiting and diarrhea symptoms disappeared completely and did not show any side effects. We also provide a brief review of the relevant literature. Including the present case, a total of 52 patients from hospitals across 17 countries were diagnosed with MPI-CDG. Age at disease onset ranged from birth to 15 years, with an onset under 2 years in most patients (43/50). Overall, patients presented with at least one or more of the following symptoms: chronic diarrhea (41/46), vomiting (23/27), hepatomegaly (39/44), hepatic fibrosis (20/37), protein-losing enteropathy (30/36), elevated serum transaminases (24/34), hyperinsulinemic-hypoglycemia (24/34), hypoalbuminemia (33/38), prolonged coagulation (26/30), splenomegaly (13/21), non-pitting edema (14/20), failure to thrive (13/36), portal hypertension (4/9), epilepsy (2/17), thrombosis (12/14), and abnormally elevated leukocytes (5). None of the patients was reported to have an intellectual disability (0/28). The majority of patients (26/30) showed clinical symptoms, and laboratory results improved after oral mannose administration. Our findings suggest that MPI-CDG should be considered in children with unexplained recurrent digestive and endocrine systems involvement, and gene examination should be performed immediately to obtain a definite diagnosis in order to begin treatment in a timely manner.
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Kim JM, Kim SK, Kim SH, Cho WK, Cho KS, Jung MH, Suh BK, Ahn MB. Transient Hyperinsulinemic Hypoglycemia Linked to PAX6 Mutation. Medicina (B Aires) 2021; 57:medicina57060582. [PMID: 34200146 PMCID: PMC8227506 DOI: 10.3390/medicina57060582] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2021] [Revised: 05/31/2021] [Accepted: 06/03/2021] [Indexed: 12/15/2022] Open
Abstract
Prolonged hyperinsulinemic hypoglycemia in infancy can result in developmental sequelae. A mutation in the paired box-6 gene (PAX6) has been reported to cause disorders in oculogenesis and neurogenesis. A limited number of cases of diabetes mellitus in adults with a PAX6 mutation suggest that the gene also plays a role in glucose homeostasis. The present case report describes a boy with a PAX6 mutation, born with anophthalmia, who underwent hypoglycemic seizures starting at 5 months old, and showed a prediabetic condition at 60 months. This patient provides novel evidence that connects PAX6 to glucose homeostasis and highlights that life-threatening hypoglycemia or early onset glucose intolerance may be encountered. The role of PAX6 in glucose metabolism and insulin regulation should be further investigated.
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Affiliation(s)
| | | | | | | | | | | | | | - Moon-Bae Ahn
- Correspondence: ; Tel.: +82-2-2258-6756 or +82-2-537-4544
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Sanchez Caballero L, Gorgogietas V, Arroyo MN, Igoillo-Esteve M. Molecular mechanisms of β-cell dysfunction and death in monogenic forms of diabetes. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2021; 359:139-256. [PMID: 33832649 DOI: 10.1016/bs.ircmb.2021.02.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Monogenetic forms of diabetes represent 1%-5% of all diabetes cases and are caused by mutations in a single gene. These mutations, that affect genes involved in pancreatic β-cell development, function and survival, or insulin regulation, may be dominant or recessive, inherited or de novo. Most patients with monogenic diabetes are very commonly misdiagnosed as having type 1 or type 2 diabetes. The severity of their symptoms depends on the nature of the mutation, the function of the affected gene and, in some cases, the influence of additional genetic or environmental factors that modulate severity and penetrance. In some patients, diabetes is accompanied by other syndromic features such as deafness, blindness, microcephaly, liver and intestinal defects, among others. The age of diabetes onset may also vary from neonatal until early adulthood manifestations. Since the different mutations result in diverse clinical presentations, patients usually need different treatments that range from just diet and exercise, to the requirement of exogenous insulin or other hypoglycemic drugs, e.g., sulfonylureas or glucagon-like peptide 1 analogs to control their glycemia. As a consequence, awareness and correct diagnosis are crucial for the proper management and treatment of monogenic diabetes patients. In this chapter, we describe mutations causing different monogenic forms of diabetes associated with inadequate pancreas development or impaired β-cell function and survival, and discuss the molecular mechanisms involved in β-cell demise.
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Affiliation(s)
- Laura Sanchez Caballero
- ULB Center for Diabetes Research (UCDR), Université Libre de Bruxelles, Brussels, Belgium. http://www.ucdr.be/
| | - Vyron Gorgogietas
- ULB Center for Diabetes Research (UCDR), Université Libre de Bruxelles, Brussels, Belgium. http://www.ucdr.be/
| | - Maria Nicol Arroyo
- ULB Center for Diabetes Research (UCDR), Université Libre de Bruxelles, Brussels, Belgium. http://www.ucdr.be/
| | - Mariana Igoillo-Esteve
- ULB Center for Diabetes Research (UCDR), Université Libre de Bruxelles, Brussels, Belgium. http://www.ucdr.be/.
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Tian W, Zhu XR, Qiao CY, Ma YN, Yang FY, Zhou Z, Feng JP, Sun R, Xie RR, Lu J, Cao X, Zhou JB, Yang JK. Heterozygous PAX6 mutations may lead to hyper-proinsulinaemia and glucose intolerance: A case-control study in families with congenital aniridia. Diabet Med 2021; 38:e14456. [PMID: 33169869 DOI: 10.1111/dme.14456] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/13/2020] [Revised: 10/07/2020] [Accepted: 10/08/2020] [Indexed: 12/16/2022]
Abstract
AIM PAX6 is a transcription factor involved in embryonic development of many organs, including the eyes and the pancreas. Mutations of PAX6 gene is the main cause of a rare disease, congenital aniridia (CA). This case-control study aims to investigate the effects of PAX6 mutations on glucose metabolism and insulin secretion in families with CA. METHODS In all, 21 families with CA were screened by Sanger sequencing. Patients with PAX6 mutations and CA (cases) and age-matched healthy family members (controls) were enrolled. Oral glucose tolerance test (OGTT) was performed to detect diabetes or impaired glucose tolerance (IGT). Insulin and proinsulin secretion were evaluated. RESULTS Among 21 CA families, heterozygous PAX6 mutations were detected in five families. Among cases (n = 10) from the five families, two were diagnosed with newly identified diabetes and another two were diagnosed with IGT. Among controls (n = 12), two had IGT. The levels of haemoglobin A1c were 36 ± 4 mmol/mol (5.57 ± 0.46%) and 32 ± 5 mmol/L (5.21 ± 0.54%) in the cases and the controls, respectively (p = 0.049). More importantly, levels of proinsulin in the cases were significantly higher than that of the controls, despite similar levels of total insulin. The areas under the curve of proinsulin in the cases (6425 ± 4390) were significantly higher than that of the controls (3709 ± 1769) (p = 0.032). CONCLUSION PAX6 may participate in the production of proinsulin to insulin and heterozygous PAX6 mutations may be associated with glucose metabolism in CA patients.
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Affiliation(s)
- Wei Tian
- Beijing Key Laboratory of Diabetes Research and Care, Department of Endocrinology, Beijing Tongren Hospital, Capital Medical University, Beijing, China
| | - Xiao-Rong Zhu
- Beijing Key Laboratory of Diabetes Research and Care, Department of Endocrinology, Beijing Tongren Hospital, Capital Medical University, Beijing, China
- Beijing Diabetes Institute, Beijing, China
| | - Chun-Yan Qiao
- Department of Ophthalmology, Beijing Tongren Hospital, Capital Medical University, Beijing, China
| | - Ying-Nan Ma
- Beijing Institute of Ophthalmology, Beijing, China
| | - Fang-Yuan Yang
- Beijing Key Laboratory of Diabetes Research and Care, Department of Endocrinology, Beijing Tongren Hospital, Capital Medical University, Beijing, China
- Beijing Diabetes Institute, Beijing, China
| | - Zhen Zhou
- Department of Mathematics, School of Biomedical Engineering, Capital Medical University, Beijing, China
| | - Jian-Ping Feng
- Beijing Key Laboratory of Diabetes Research and Care, Department of Endocrinology, Beijing Tongren Hospital, Capital Medical University, Beijing, China
| | - Ran Sun
- Beijing Key Laboratory of Diabetes Research and Care, Department of Endocrinology, Beijing Tongren Hospital, Capital Medical University, Beijing, China
| | - Rong-Rong Xie
- Beijing Key Laboratory of Diabetes Research and Care, Department of Endocrinology, Beijing Tongren Hospital, Capital Medical University, Beijing, China
| | - Jing Lu
- Beijing Key Laboratory of Diabetes Research and Care, Department of Endocrinology, Beijing Tongren Hospital, Capital Medical University, Beijing, China
- Beijing Diabetes Institute, Beijing, China
| | - Xi Cao
- Beijing Key Laboratory of Diabetes Research and Care, Department of Endocrinology, Beijing Tongren Hospital, Capital Medical University, Beijing, China
- Beijing Diabetes Institute, Beijing, China
| | - Jian-Bo Zhou
- Beijing Key Laboratory of Diabetes Research and Care, Department of Endocrinology, Beijing Tongren Hospital, Capital Medical University, Beijing, China
- Beijing Diabetes Institute, Beijing, China
| | - Jin-Kui Yang
- Beijing Key Laboratory of Diabetes Research and Care, Department of Endocrinology, Beijing Tongren Hospital, Capital Medical University, Beijing, China
- Beijing Diabetes Institute, Beijing, China
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Osinski C, Le Gléau L, Poitou C, de Toro-Martin J, Genser L, Fradet M, Soula HA, Leturque A, Blugeon C, Jourdren L, Hubert EL, Clément K, Serradas P, Ribeiro A. Type 2 diabetes is associated with impaired jejunal enteroendocrine GLP-1 cell lineage in human obesity. Int J Obes (Lond) 2020; 45:170-183. [PMID: 33037328 PMCID: PMC7752761 DOI: 10.1038/s41366-020-00694-1] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/05/2020] [Revised: 09/07/2020] [Accepted: 09/26/2020] [Indexed: 12/15/2022]
Abstract
Objectives Altered enteroendocrine cell (EEC) function in obesity and type 2 diabetes is not fully understood. Understanding the transcriptional program that controls EEC differentiation is important because some EEC types harbor significant therapeutic potential for type 2 diabetes. Methods EEC isolation from jejunum of obese individuals with (ObD) or without (Ob) type 2 diabetes was obtained with a new method of cell sorting. EEC transcriptional profiles were established by RNA-sequencing in a first group of 14 Ob and 13 ObD individuals. EEC lineage and densities were studied in the jejunum of a second independent group of 37 Ob, 21 ObD and 22 non obese (NOb) individuals. Results The RNA seq analysis revealed a distinctive transcriptomic signature and a decreased differentiation program in isolated EEC from ObD compared to Ob individuals. In the second independent group of ObD, Ob and NOb individuals a decreased GLP-1 cell lineage and GLP-1 maturation from proglucagon, were observed in ObD compared to Ob individuals. Furthermore, jejunal density of GLP-1-positive cells was significantly reduced in ObD compared to Ob individuals. Conclusions These results highlight that the transcriptomic signature of EEC discriminate obese subjects according to their diabetic status. Furthermore, type 2 diabetes is associated with reduced GLP-1 cell differentiation and proglucagon maturation leading to low GLP-1-cell density in human obesity. These mechanisms could account for the decrease plasma GLP-1 observed in metabolic diseases.
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Affiliation(s)
- Céline Osinski
- Sorbonne Université, INSERM, Nutrition and obesities: systemic approaches, F-75013, Paris, France
| | - Léa Le Gléau
- Sorbonne Université, INSERM, Nutrition and obesities: systemic approaches, F-75013, Paris, France
| | - Christine Poitou
- Sorbonne Université, INSERM, Nutrition and obesities: systemic approaches, F-75013, Paris, France.,Nutrition Department, Pitié-Salpêtrière hospital, Assistance Publique/Hôpitaux de Paris, F-75013, Paris, France
| | - Juan de Toro-Martin
- Sorbonne Université, Université de Paris, INSERM, Cordeliers Research Center, F-75006, Paris, France.,Institute of Nutrition and Functional Foods (INAF), School of Nutrition, Université Laval, Quebec, QC, Canada
| | - Laurent Genser
- Sorbonne Université, INSERM, Nutrition and obesities: systemic approaches, F-75013, Paris, France.,Hepato-Biliary-Pancreatic Gastrointestinal Surgery and Liver Transplantation, Pitié-Salpêtrière Hospital, Assistance Publique/Hôpitaux de Paris, F-75013, Paris, France
| | - Magali Fradet
- Cytometry platform, Institut Cardiometabolism and Nutrition, F-75013, Paris, France.,Institut de Biologie, CIRB, Collège de France, F-75005, Paris, France
| | - Hédi Antoine Soula
- Sorbonne Université, INSERM, Nutrition and obesities: systemic approaches, F-75013, Paris, France
| | - Armelle Leturque
- Sorbonne Université, INSERM, Nutrition and obesities: systemic approaches, F-75013, Paris, France
| | - Corinne Blugeon
- Genomics core facility, Département de biologie, Institut de Biologie de l'ENS (IBENS), École normale supérieure, CNRS, INSERM, Université PSL, 75005, Paris, France
| | - Laurent Jourdren
- Genomics core facility, Département de biologie, Institut de Biologie de l'ENS (IBENS), École normale supérieure, CNRS, INSERM, Université PSL, 75005, Paris, France
| | - Edwige Ludiwyne Hubert
- Sorbonne Université, Université de Paris, INSERM, Cordeliers Research Center, F-75006, Paris, France.,SERVIER, ADIR, F-92284, Suresnes, cedex, France
| | - Karine Clément
- Sorbonne Université, INSERM, Nutrition and obesities: systemic approaches, F-75013, Paris, France.,Nutrition Department, Pitié-Salpêtrière hospital, Assistance Publique/Hôpitaux de Paris, F-75013, Paris, France
| | - Patricia Serradas
- Sorbonne Université, INSERM, Nutrition and obesities: systemic approaches, F-75013, Paris, France.
| | - Agnès Ribeiro
- Sorbonne Université, INSERM, Nutrition and obesities: systemic approaches, F-75013, Paris, France.
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Cheng M, Huang X, Zhang M, Huang Q. Computational and functional analyses of T2D GWAS SNPs for transcription factor binding. Biochem Biophys Res Commun 2020; 523:658-665. [PMID: 31948755 DOI: 10.1016/j.bbrc.2019.12.086] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2019] [Accepted: 12/30/2019] [Indexed: 12/31/2022]
Abstract
Genome-wide association studies (GWASs) have successfully identified numerous non-coding genetic variants for type 2 diabetes (T2D), but the functional roles underlying these non-coding variants remain largely unknown. The effects of T2D GWAS lead SNPs on transcriptional factors binding motifs were firstly analyzed via JASPAR, followed by functional validations including dual-luciferase reporter assays, biotin-based DNA pull-down assays, real-time quantitative PCR, and western blotting. The results showed that GWAS SNP rs4430796 conferred T allele specific transcriptional enhancer activity via a PAX6 binding element, and upregulated the expression of HNF1B. GWAS SNP rs4607103 showed a bidirectional modulation of ADAMTS9-AS2 and ADAMTS9 by TCF7L2 in a T allele-specific manner. GWAS SNP rs849135 conferred C allele-specific bidirectional transcriptional enhancer activity via a CREB1 binding element. Our findings have uncovered the functional mechanisms of three T2D GWAS SNPs via affecting the binding of transcription factors, providing new insights into the genetics and molecular pathogenesis of T2D.
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Affiliation(s)
- Mengrong Cheng
- Hubei Key Laboratory of Genetic Regulation and Integrative Biology, School of Life Sciences, Central China Normal University, Wuhan, PR China; College of Biology and Agricultural Resources, Huanggang Normal University, Huanggang, Hubei, PR China
| | - Xinyao Huang
- Hubei Key Laboratory of Genetic Regulation and Integrative Biology, School of Life Sciences, Central China Normal University, Wuhan, PR China
| | - Manling Zhang
- Hubei Key Laboratory of Genetic Regulation and Integrative Biology, School of Life Sciences, Central China Normal University, Wuhan, PR China
| | - Qingyang Huang
- Hubei Key Laboratory of Genetic Regulation and Integrative Biology, School of Life Sciences, Central China Normal University, Wuhan, PR China.
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Sona C, Kumar A, Dogra S, Kumar BA, Umrao D, Yadav PN. Docosahexaenoic acid modulates brain-derived neurotrophic factor via GPR40 in the brain and alleviates diabesity-associated learning and memory deficits in mice. Neurobiol Dis 2018; 118:94-107. [DOI: 10.1016/j.nbd.2018.07.002] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2017] [Revised: 06/22/2018] [Accepted: 07/04/2018] [Indexed: 12/19/2022] Open
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Yongblah K, Alford SC, Ryan BC, Chow RL, Howard PL. Protecting Pax6 3' UTR from MicroRNA-7 Partially Restores PAX6 in Islets from an Aniridia Mouse Model. MOLECULAR THERAPY. NUCLEIC ACIDS 2018; 13:144-153. [PMID: 30290306 PMCID: PMC6171161 DOI: 10.1016/j.omtn.2018.08.018] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/08/2018] [Revised: 08/16/2018] [Accepted: 08/27/2018] [Indexed: 02/06/2023]
Abstract
Aniridia is a rare congenital syndrome that is associated with reduced visual acuity and progressive loss of vision. Aniridia patients may also develop systemic health issues associated with defects in the pancreas, digestive, and central nervous systems. The spectrum of symptoms associated with aniridia is due to haploinsufficiency of the paired box 6 gene (PAX6) and its role in the development and maintenance of the affected tissues. Here, we isolated pancreatic islets from mice heterozygous for Pax6 to test whether a Pax6-specific miRNA suppression (target protector) strategy can restore PAX6 protein levels. We show that miR-7 and miR-375 target specific sites within the Pax6 3' UTR in a mouse pancreatic β-insulinoma cell line. Tough decoys (Tuds) against miR-7 and miR-375 increase expression of a mouse Pax6 3' UTR luciferase reporter and increase PAX6 protein levels in these cells. Finally, we demonstrate that the shielding of the miR-7 binding site with a target protector restores PAX6 protein levels in the Pax6 heterozygous islets. The data presented here represent a proof of concept for RNA-based therapy for the progressive defects associated with aniridia and suggest the target protector approach may be a useful therapeutic strategy for other haploinsufficiency diseases.
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Affiliation(s)
- Kevin Yongblah
- Department of Biochemistry and Microbiology, University of Victoria, P.O. Box 1700 STN CSC, Victoria, BC V8W2Y2, Canada
| | - Spencer C Alford
- Department of Biochemistry and Microbiology, University of Victoria, P.O. Box 1700 STN CSC, Victoria, BC V8W2Y2, Canada
| | - Bridget C Ryan
- Department of Biology, University of Victoria, P.O. Box 1700 STN CSC, Victoria, BC V8W 2Y2, Canada
| | - Robert L Chow
- Department of Biology, University of Victoria, P.O. Box 1700 STN CSC, Victoria, BC V8W 2Y2, Canada
| | - Perry L Howard
- Department of Biochemistry and Microbiology, University of Victoria, P.O. Box 1700 STN CSC, Victoria, BC V8W2Y2, Canada.
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Huang WQ, Guo JH, Yuan C, Cui YG, Diao FY, Yu MK, Liu JY, Ruan YC, Chan HC. Abnormal CFTR Affects Glucagon Production by Islet α Cells in Cystic Fibrosis and Polycystic Ovarian Syndrome. Front Physiol 2017; 8:835. [PMID: 29204121 PMCID: PMC5698272 DOI: 10.3389/fphys.2017.00835] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2017] [Accepted: 10/09/2017] [Indexed: 12/26/2022] Open
Abstract
Glucagon, produced by islet α cells, functions to increase blood glucose. Abnormal glucose levels are often seen in cystic fibrosis (CF), a systematic disease caused by mutations of the CF transmembrane conductance regulator (CFTR), and in polycystic ovarian syndrome (PCOS), an endocrine disorder featured with hyperandrogenism affecting 5-10% women of reproductive age. Here, we explored the role of CFTR in glucagon production in α cells and its possible contribution to glucagon disturbance in CF and PCOS. We found elevated fasting glucagon levels in CFTR mutant (DF508) mice compared to the wildtypes. Glucagon and prohormone convertase 2 (PC2) were also upregulated in CFTR inhibitor-treated or DF508 islets, as compared to the controls or wildtypes, respectively. Dihydrotestosterone (DHT)-induced PCOS rats exhibited significantly lower fasting glucagon levels with higher CFTR expression in α cells compared to that of controls. Treatment of mouse islets or αTC1-9 cells with DHT enhanced CFTR expression and reduced the levels of glucagon and PC2. The inhibitory effect of DHT on glucagon production was blocked by CFTR inhibitors in mouse islets, and mimicked by overexpressing CFTR in αTC1-9 cells with reduced phosphorylation of the cAMP/Ca2+ response element binding protein (p-CREB), a key transcription factor for glucagon and PC2. These results revealed a previously undefined role of CFTR in suppressing glucagon production in α-cells, defects in which may contribute to glucose metabolic disorder seen in CF and PCOS.
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Affiliation(s)
- Wen Qing Huang
- Epithelial Cell Biology Research Centre, School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong, Hong Kong
| | - Jing Hui Guo
- Epithelial Cell Biology Research Centre, School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong, Hong Kong
- Department of Pathophysiology, Key Laboratory of State Administration of Traditional Chinese Medicine of the People's Republic of China, School of Medicine, Jinan University, Guangzhou, China
| | - Chun Yuan
- State Key Laboratory of Reproductive Medicine, Clinical Center of Reproductive Medicine, First Affiliated Hospital, Nanjing Medical University, Nanjing, China
| | - Yu Gui Cui
- State Key Laboratory of Reproductive Medicine, Clinical Center of Reproductive Medicine, First Affiliated Hospital, Nanjing Medical University, Nanjing, China
| | - Fei Yang Diao
- State Key Laboratory of Reproductive Medicine, Clinical Center of Reproductive Medicine, First Affiliated Hospital, Nanjing Medical University, Nanjing, China
| | - Mei Kuen Yu
- Epithelial Cell Biology Research Centre, School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong, Hong Kong
- Department of Biomedical Engineering, Faculty of Engineering, The Hong Kong Polytechnic University, Hong Kong, Hong Kong
| | - Jia Yin Liu
- State Key Laboratory of Reproductive Medicine, Clinical Center of Reproductive Medicine, First Affiliated Hospital, Nanjing Medical University, Nanjing, China
| | - Ye Chun Ruan
- Epithelial Cell Biology Research Centre, School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong, Hong Kong
- Department of Biomedical Engineering, Faculty of Engineering, The Hong Kong Polytechnic University, Hong Kong, Hong Kong
| | - Hsiao Chang Chan
- Epithelial Cell Biology Research Centre, School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong, Hong Kong
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Sabrautzki S, Kaiser G, Przemeck GKH, Gerst F, Lorza-Gil E, Panse M, Sartorius T, Hoene M, Marschall S, Häring HU, Hrabě de Angelis M, Ullrich S. Point mutation of Ffar1 abrogates fatty acid-dependent insulin secretion, but protects against HFD-induced glucose intolerance. Mol Metab 2017; 6:1304-1312. [PMID: 29031729 PMCID: PMC5641630 DOI: 10.1016/j.molmet.2017.07.007] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/16/2016] [Revised: 07/05/2017] [Accepted: 07/11/2017] [Indexed: 01/06/2023] Open
Abstract
Objective The fatty acid receptor 1 (FFAR1/GPR40) mediates fatty acid-dependent augmentation of glucose-induced insulin secretion (GIIS) in pancreatic β-cells. Genetically engineered Ffar1-knockout/congenic mice univocally displayed impaired fatty acid-mediated insulin secretion, but in vivo experiments delivered controversial results regarding the function of FFAR1 in glucose homeostasis and liver steatosis. This study presents a new coisogenic mouse model carrying a point mutation in Ffar1 with functional consequence. These mice reflect the situations in humans in which point mutations can lead to protein malfunction and disease development. Methods The Munich N-ethyl-N-nitrosourea (ENU) mutagenesis-derived F1 archive containing over 16,800 sperms and corresponding DNA samples was screened for mutations in the coding region of Ffar1. Two missense mutations (R258W and T146S) in the extracellular domain of the protein were chosen and homozygote mice were generated. The functional consequence of these mutations was examined in vitro in isolated islets and in vivo in chow diet and high fat diet fed mice. Results Palmitate, 50 μM, and the FFAR1 agonist TUG-469, 3 μM, stimulated insulin secretion in islets of Ffar1T146S/T146S mutant mice and of wild-type littermates, while in islets of Ffar1R258W/R258W mutant mice, these stimulatory effects were abolished. Insulin content and mRNA levels of Ffar1, Glp1r, Ins2, Slc2a2, Ppara, and Ppard were not significantly different between wild-type and Ffar1R258W/R258W mouse islets. Palmitate exposure, 600 μM, significantly increased Ppara mRNA levels in wild-type but not in Ffar1R258W/R258W mouse islets. On the contrary, Slc2a2 mRNA levels were significantly reduced in both wild-type and Ffar1R258W/R258W mouse islets after palmitate treatment. HFD feeding induced glucose intolerance in wild-type mice. Ffar1R258W/R258W mutant mice remained glucose tolerant although their body weight gain, liver steatosis, insulin resistance, and plasma insulin levels were not different from those of wild-type littermates. Worth mentioning, fasting plasma insulin levels were lower in Ffar1R258W/R258W mice. Conclusion A point mutation in Ffar1 abrogates the stimulatory effect of palmitate on GIIS, an effect that does not necessarily translate to HFD-induced glucose intolerance. Generation of mice carrying point mutations in Ffar1 using ENU. FFAR1 point mutation R258W abrogates fatty acid-induced insulin secretion. Dysfunctional FFAR1 inhibits the development of diet-induced glucose intolerance.
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Affiliation(s)
- Sibylle Sabrautzki
- Helmholtz Zentrum München, German Research Center for Environmental Health (GmbH), Institute of Experimental Genetics and the German Mouse Clinic, 85764 Neuherberg, Germany; Research Unit Comparative Medicine, Ingolstädter Landstrasse 1, 85764 Neuherberg, Germany
| | - Gabriele Kaiser
- Institute for Diabetes Research and Metabolic Diseases of the Helmholtz Zentrum München at the University of Tübingen (IDM), 72076 Tübingen, Germany
| | - Gerhard K H Przemeck
- Helmholtz Zentrum München, German Research Center for Environmental Health (GmbH), Institute of Experimental Genetics and the German Mouse Clinic, 85764 Neuherberg, Germany
| | - Felicia Gerst
- Institute for Diabetes Research and Metabolic Diseases of the Helmholtz Zentrum München at the University of Tübingen (IDM), 72076 Tübingen, Germany
| | - Estela Lorza-Gil
- Institute for Diabetes Research and Metabolic Diseases of the Helmholtz Zentrum München at the University of Tübingen (IDM), 72076 Tübingen, Germany
| | - Madhura Panse
- University Hospital Tübingen, Department of Internal Medicine, Division of Endocrinology, Diabetology, Vascular Medicine, Nephrology and Clinical Chemistry, Otfried-Müller-Strasse 10, 72076 Tübingen, Germany
| | - Tina Sartorius
- University Hospital Tübingen, Department of Internal Medicine, Division of Endocrinology, Diabetology, Vascular Medicine, Nephrology and Clinical Chemistry, Otfried-Müller-Strasse 10, 72076 Tübingen, Germany
| | - Miriam Hoene
- University Hospital Tübingen, Department of Internal Medicine, Division of Endocrinology, Diabetology, Vascular Medicine, Nephrology and Clinical Chemistry, Otfried-Müller-Strasse 10, 72076 Tübingen, Germany
| | - Susan Marschall
- Helmholtz Zentrum München, German Research Center for Environmental Health (GmbH), Institute of Experimental Genetics and the German Mouse Clinic, 85764 Neuherberg, Germany
| | - Hans-Ulrich Häring
- Institute for Diabetes Research and Metabolic Diseases of the Helmholtz Zentrum München at the University of Tübingen (IDM), 72076 Tübingen, Germany; University Hospital Tübingen, Department of Internal Medicine, Division of Endocrinology, Diabetology, Vascular Medicine, Nephrology and Clinical Chemistry, Otfried-Müller-Strasse 10, 72076 Tübingen, Germany
| | - Martin Hrabě de Angelis
- Helmholtz Zentrum München, German Research Center for Environmental Health (GmbH), Institute of Experimental Genetics and the German Mouse Clinic, 85764 Neuherberg, Germany; Chair of Experimental Genetics, School of Life Sciences Weihenstephan, Technische Universität München, Alte Akademie 8, 85354 München, Germany
| | - Susanne Ullrich
- Institute for Diabetes Research and Metabolic Diseases of the Helmholtz Zentrum München at the University of Tübingen (IDM), 72076 Tübingen, Germany; University Hospital Tübingen, Department of Internal Medicine, Division of Endocrinology, Diabetology, Vascular Medicine, Nephrology and Clinical Chemistry, Otfried-Müller-Strasse 10, 72076 Tübingen, Germany.
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11
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Regazzo D, Losa M, Albiger NM, Terreni MR, Vazza G, Ceccato F, Emanuelli E, Denaro L, Scaroni C, Occhi G. The GIP/GIPR axis is functionally linked to GH-secretion increase in a significant proportion of gsp- somatotropinomas. Eur J Endocrinol 2017; 176:543-553. [PMID: 28179449 DOI: 10.1530/eje-16-0831] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/04/2016] [Revised: 02/01/2017] [Accepted: 02/07/2017] [Indexed: 01/03/2023]
Abstract
OBJECTIVE Glucose-dependent insulinotropic polypeptide receptor (GIPR) overexpression has been recently described in a proportion of gsp- somatotropinomas and suggested to be associated with the paradoxical increase of GH (GH-PI) during an oral glucose load. DESIGN AND METHODS This study was aimed at linking the GIP/GIPR pathway to GH secretion in 25 somatotropinomas-derived primary cultures and correlating molecular with clinical features in acromegalic patients. Given the impairment of the GIP/GIPR axis in acromegaly, an additional aim was to assess the effect of GH/IGF-1 stimulation on GIP expression in the enteroendocrine cell line STC-1. RESULTS Nearly 80% of GIPR-expressing somatotropinomas, all of them negative for gsp mutations, show increased GH secretion upon GIP stimulation, higher sensitivity to Forskolin but not to somatostatin analogs. Besides increased frequency of GH-PI, GIPR overexpression does not appear to affect acromegalic patients' clinical features. In STC-1 cells transfected with GIP promoter-driven luciferase vector, IGF-1 but not GH induced dose-dependent increase in luciferase activity. CONCLUSIONS We demonstrate that GIPR mediates the GH-PI in a significant proportion of gsp- acromegalic patients. In these cases, the stimulatory effect of IGF-1 on GIP promoter support the hypothesis of a functional GH/IGF-1/GIP axis. Further studies based on larger cohorts and the development of a stable transgenic model with inducible GIPR overexpression targeted to pituitary somatotroph lineage will be mandatory to establish the real role of GIPR in the pathogenesis of somatotropinomas.
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Affiliation(s)
- D Regazzo
- Endocrinology DivisionDepartment of Medicine, Hospital/University of Padova, Padova, Italy
| | - M Losa
- Pituitary UnitDepartment of Neurosurgery
| | - N M Albiger
- Endocrinology DivisionDepartment of Medicine, Hospital/University of Padova, Padova, Italy
| | - M R Terreni
- Pathology UnitIstituto Scientifico San Raffaele, Università Vita-Salute, Milano, Italy
| | - G Vazza
- Department of BiologyUniversity of Padova, Padova, Italy
| | - F Ceccato
- Endocrinology DivisionDepartment of Medicine, Hospital/University of Padova, Padova, Italy
| | | | - L Denaro
- Department of NeuroscienceHospital/University of Padova, Padova, Italy
| | - C Scaroni
- Endocrinology DivisionDepartment of Medicine, Hospital/University of Padova, Padova, Italy
| | - G Occhi
- Department of BiologyUniversity of Padova, Padova, Italy
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12
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Cheng M, Liu X, Yang M, Han L, Xu A, Huang Q. Computational analyses of type 2 diabetes-associated loci identified by genome-wide association studies. J Diabetes 2017; 9:362-377. [PMID: 27121852 DOI: 10.1111/1753-0407.12421] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/02/2015] [Revised: 03/31/2016] [Accepted: 04/23/2016] [Indexed: 12/18/2022] Open
Abstract
BACKGROUND Genome-wide association studies (GWAS) of type 2 diabetes (T2D) have discovered a number of loci that contribute to susceptibility to the disease. Future challenges include elucidation of functional mechanisms through which these GWAS-identified loci modulate T2D disease risk. The aim of the present study was to comprehensively characterize T2D associated single nucleotide polymorphisms (SNPs) and genes through computational approaches. METHODS Computational biology approaches used in the present study included comparative genomic analyses and functional annotation using GWAS3D and RegulomeDB, investigation of the effects of T2D-associated SNPs on miRNA binding and protein phosphorylation, and gene ontology, pathway enrichment, protein-protein interaction (PPI) networks and functional module analysis of T2D-associated genes from previously published GWAS. RESULTS Computational analysis identified a number of T2D GWAS-associated SNPs that were located at protein binding sites, including CCCTC-binding factor (CTCF), E1A binding protein p300 (EP300), hepatocyte nuclear factor 4alpha (HNF4A), transcription factor 7 like 2 (TCF7L2), forkhead box A1 (FOXA1) and A2 (FOXA2), and potentially affected the binding of miRNAs and protein phosphorylation. Pathway enrichment analysis confirmed two well-known maturity onset diabetes of the young and T2D pathways, whereas PPI network analysis identified highly interconnected "hub" genes, such as TCF7L2, melatonin receptor 1B (MTNR1B), and solute carrier family 30 (zinc transporter), member 8 (SLC30A8), that created two tight subnetworks. CONCLUSIONS The results provide objectives and clues for future experimental studies and further insights into the molecular pathogenesis of T2D.
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Affiliation(s)
- Mengrong Cheng
- College of Life Sciences, Central China Normal University, Wuhan, China
| | - Xinhong Liu
- College of Life Sciences, Central China Normal University, Wuhan, China
| | - Mei Yang
- College of Life Sciences, Central China Normal University, Wuhan, China
| | - Lanchun Han
- College of Life Sciences, Central China Normal University, Wuhan, China
- Institute of Public Health and Molecular Medicine Analysis, Central China Normal University, Wuhan, China
| | - Aimin Xu
- Li Cha Chung Faculty of Medicine, The University of Hong Kong, Hong Kong, China
| | - Qingyang Huang
- College of Life Sciences, Central China Normal University, Wuhan, China
- Institute of Public Health and Molecular Medicine Analysis, Central China Normal University, Wuhan, China
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13
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Abstract
Of the 415 million people suffering from diabetes worldwide, 90% have type 2 diabetes. Type 2 diabetes is characterized by hyperglycemia and occurs in obese individuals as a result of insulin resistance and inadequate insulin levels. Accordingly, diabetes drugs are tailored to enhance glucose disposal or target the pancreatic islet β cell to increase insulin secretion. The majority of the present-day insulin secretagogues, however, increase the risk of iatrogenic hypoglycemia, and hence alternatives are actively sought. The long-chain fatty acid, G protein-coupled receptor FFA1/Gpr40, is expressed in β cells, and its activation potentiates insulin secretion in a glucose-dependent manner. Preclinical data indicate that FFA1 agonism is an effective treatment to restore glucose homeostasis in rodent models of diabetes. This initial success prompted clinical trials in type 2 diabetes patients, the results of which were promising; however, the field suffered a significant setback when the lead compound TAK-875/fasiglifam was withdrawn from clinical development due to liver safety concerns. Nevertheless, recent developments have brought to light a surprising complexity of FFA1 agonist action, signaling diversity, and biological outcomes, raising hopes that with a greater understanding of the mechanisms at play the second round will be more successful.
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Affiliation(s)
- Julien Ghislain
- Montreal Diabetes Research Center, University of Montreal, Montreal, QC, Canada
- CRCHUM, University of Montreal, 900 rue St Denis, Montreal, QC, Canada, H2X 0A9
| | - Vincent Poitout
- Montreal Diabetes Research Center, University of Montreal, Montreal, QC, Canada.
- CRCHUM, University of Montreal, 900 rue St Denis, Montreal, QC, Canada, H2X 0A9.
- Department of Medicine, University of Montreal, Montreal, QC, Canada.
- Department of Biochemistry and Molecular Medicine, University of Montreal, Montreal, QC, Canada.
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14
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Mirasierra M, Vallejo M. Glucose-dependent downregulation of glucagon gene expression mediated by selective interactions between ALX3 and PAX6 in mouse alpha cells. Diabetologia 2016; 59:766-75. [PMID: 26739814 DOI: 10.1007/s00125-015-3849-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/15/2015] [Accepted: 12/07/2015] [Indexed: 12/11/2022]
Abstract
AIMS/HYPOTHESIS The stimulation of glucagon secretion in response to decreased glucose levels has been studied extensively. In contrast, little is known about the regulation of glucagon gene expression in response to fluctuations in glucose concentration. Paired box 6 (PAX6) is a key transcription factor that regulates the glucagon promoter by binding to the G1 and G3 elements. Here, we investigated the role of the transcription factor aristaless-like homeobox 3 (ALX3) as a glucose-dependent modulator of PAX6 activity in alpha cells. METHODS Experiments were performed in wild-type or Alx3-deficient islets and alphaTC1 cells. We used chromatin immunoprecipitations and electrophoretic mobility shift assays for DNA binding, immunoprecipitations and pull-down assays for protein interactions, transfected cells for promoter activity, and small interfering RNA and quantitative RT-PCR for gene expression. RESULTS Elevated glucose concentration resulted in stimulated expression of Alx3 and decreased glucagon gene expression in wild-type islets. In ALX3-deficient islets, basal glucagon levels were non-responsive to changes in glucose concentration. In basal conditions ALX3 bound to the glucagon promoter at G3, but not at G1. ALX3 could form heterodimers with PAX6 that were permissive for binding to G3 but not to G1. Thus, increasing the levels of ALX3 in response to glucose resulted in the sequestration of PAX6 by ALX3 for binding to G1, thus reducing glucagon promoter activation and glucagon gene expression. CONCLUSIONS/INTERPRETATION Glucose-stimulated expression of ALX3 in alpha cells provides a regulatory mechanism for the downregulation of glucagon gene expression by interfering with PAX6-mediated transactivation on the glucagon G1 promoter element.
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Affiliation(s)
- Mercedes Mirasierra
- Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Madrid, Spain
- Instituto de Investigaciones Biomédicas Alberto Sols, Consejo Superior de Investigaciones Científicas/Universidad Autónoma de Madrid (CSIC/UAM), Calle Arturo Duperier 4, 28029, Madrid, Spain
| | - Mario Vallejo
- Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Madrid, Spain.
- Instituto de Investigaciones Biomédicas Alberto Sols, Consejo Superior de Investigaciones Científicas/Universidad Autónoma de Madrid (CSIC/UAM), Calle Arturo Duperier 4, 28029, Madrid, Spain.
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15
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Origins and evolvability of the PAX family. Semin Cell Dev Biol 2015; 44:64-74. [DOI: 10.1016/j.semcdb.2015.08.014] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2015] [Revised: 08/07/2015] [Accepted: 08/22/2015] [Indexed: 01/18/2023]
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16
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Brocato J, Hernandez M, Laulicht F, Sun H, Shamy M, Alghamdi MA, Khoder MI, Kluz T, Chen LC, Costa M. In Vivo Exposures to Particulate Matter Collected from Saudi Arabia or Nickel Chloride Display Similar Dysregulation of Metabolic Syndrome Genes. JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH. PART A 2015; 78:1421-36. [PMID: 26692068 PMCID: PMC4709028 DOI: 10.1080/15287394.2015.1095689] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Particulate matter (PM) exposures have been linked to mortality, low birth weights, hospital admissions, and diseases associated with metabolic syndrome, including diabetes mellitus, cardiovascular disease, and obesity. In a previous in vitro and in vivo study, data demonstrated that PM(10μm) collected from Jeddah, Saudi Arabia (PMSA), altered expression of genes involved in lipid and cholesterol metabolism, as well as many other genes associated with metabolic disorders. PMSA contains a relatively high concentration of nickel (Ni), known to be linked to several metabolic disorders. In order to evaluate whether Ni and PM exposures induce similar gene expression profiles, mice were exposed to 100 μg/50 μl PM(SA) (PM-100), 50 μg/50 μl nickel chloride (Ni-50), or 100 μg/50 μl nickel chloride (Ni-100) twice per week for 4 wk and hepatic gene expression changes were determined. Ultimately, 55 of the same genes were altered in all 3 exposures. However, where the two Ni groups differed markedly was in the regulation (up or down) of these genes. Ni-100 and PM-100 groups displayed similar regulations, whereby 104 of the 107 genes were similarly modulated. Many of the 107 genes are involved in metabolic syndrome and include ALDH4A1, BCO2, CYP1A, CYP2U, TOP2A. In addition, the top affected pathways, such as fatty acid α-oxidation, and lipid and carbohydrate metabolism, are involved in metabolic diseases. Most notably, the top diseased outcome affected by these changes in gene expression was cardiovascular disease. Given these data, it appears that Ni and PM(SA) exposures display similar gene expression profiles, modulating the expression of genes involved in metabolic disorders.
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Affiliation(s)
- Jason Brocato
- Department of Environmental Medicine, NYU School of Medicine, NY, NY, 10016 USA
| | - Michelle Hernandez
- Department of Environmental Medicine, NYU School of Medicine, NY, NY, 10016 USA
| | - Freda Laulicht
- Department of Environmental Medicine, NYU School of Medicine, NY, NY, 10016 USA
| | - Hong Sun
- Department of Environmental Medicine, NYU School of Medicine, NY, NY, 10016 USA
| | - Magdy Shamy
- Department of Environmental Sciences, Faculty of Meteorology, Environmental and Arid Land Agriculture, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Mansour A. Alghamdi
- Department of Environmental Sciences, Faculty of Meteorology, Environmental and Arid Land Agriculture, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Mamdouh I. Khoder
- Department of Environmental Sciences, Faculty of Meteorology, Environmental and Arid Land Agriculture, King Abdulaziz University, Jeddah, Saudi Arabia
- Center of Excellence in Environmental Studies, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Thomas Kluz
- Department of Environmental Medicine, NYU School of Medicine, NY, NY, 10016 USA
| | - Lung-Chi Chen
- Department of Environmental Medicine, NYU School of Medicine, NY, NY, 10016 USA
| | - Max Costa
- Department of Environmental Medicine, NYU School of Medicine, NY, NY, 10016 USA
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17
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Heddad Masson M, Poisson C, Guérardel A, Mamin A, Philippe J, Gosmain Y. Foxa1 and Foxa2 regulate α-cell differentiation, glucagon biosynthesis, and secretion. Endocrinology 2014; 155:3781-92. [PMID: 25057789 DOI: 10.1210/en.2013-1843] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
The Forkhead box A transcription factors are major regulators of glucose homeostasis. They show both distinct and redundant roles during pancreas development and in adult mouse β-cells. In vivo ablation studies have revealed critical implications of Foxa1 on glucagon biosynthesis and requirement of Foxa2 in α-cell terminal differentiation. In order to examine the respective role of these factors in mature α-cells, we used small interfering RNA (siRNA) directed against Foxa1 and Foxa2 in rat primary pancreatic α-cells and rodent α-cell lines leading to marked decreases in Foxa1 and Foxa2 mRNA levels and proteins. Both Foxa1 and Foxa2 control glucagon gene expression specifically through the G2 element. Although we found that Foxa2 controls the expression of the glucagon, MafB, Pou3f4, Pcsk2, Nkx2.2, Kir6.2, and Sur1 genes, Foxa1 only regulates glucagon gene expression. Interestingly, the Isl1 and Gipr genes were not controlled by either Foxa1 or Foxa2 alone but by their combination. Foxa1 and Foxa2 directly activate and bind the promoter region the Nkx2.2, Kir6.2 and Sur1, Gipr, Isl1, and Pou3f4 genes. We also demonstrated that glucagon secretion is affected by the combined effects of Foxa1 and Foxa2 but not by either one alone. Our results indicate that Foxa1 and Foxa2 control glucagon biosynthesis and secretion as well as α-cell differentiation with both common and unique target genes.
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Affiliation(s)
- Mounia Heddad Masson
- Department of Endocrinology, Diabetes, Hypertension and Nutrition, University Hospital of Geneva, Medical School, 1211 Geneva 14, Switzerland
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18
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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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19
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Jaramillo M, Mathew S, Task K, Barner S, Banerjee I. Potential for pancreatic maturation of differentiating human embryonic stem cells is sensitive to the specific pathway of definitive endoderm commitment. PLoS One 2014; 9:e94307. [PMID: 24743345 PMCID: PMC3990550 DOI: 10.1371/journal.pone.0094307] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2014] [Accepted: 03/15/2014] [Indexed: 11/19/2022] Open
Abstract
This study provides a detailed experimental and mathematical analysis of the impact of the initial pathway of definitive endoderm (DE) induction on later stages of pancreatic maturation. Human embryonic stem cells (hESCs) were induced to insulin-producing cells following a directed-differentiation approach. DE was induced following four alternative pathway modulations. DE derivatives obtained from these alternate pathways were subjected to pancreatic progenitor (PP) induction and maturation and analyzed at each stage. Results indicate that late stage maturation is influenced by the initial pathway of DE commitment. Detailed quantitative analysis revealed WNT3A and FGF2 induced DE cells showed highest expression of insulin, are closely aligned in gene expression patterning and have a closer resemblance to pancreatic organogenesis. Conversely, BMP4 at DE induction gave most divergent differentiation dynamics with lowest insulin upregulation, but highest glucagon upregulation. Additionally, we have concluded that early analysis of PP markers is indicative of its potential for pancreatic maturation.
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Affiliation(s)
- Maria Jaramillo
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Shibin Mathew
- Department of Chemical and Petroleum Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Keith Task
- Department of Chemical and Petroleum Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Sierra Barner
- Department of Chemical and Petroleum Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Ipsita Banerjee
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
- Department of Chemical and Petroleum Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
- McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
- * E-mail:
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20
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Tsui S, Dai W, Lu L. CCCTC-binding factor mediates effects of glucose on beta cell survival. Cell Prolif 2013; 47:28-37. [PMID: 24354619 DOI: 10.1111/cpr.12085] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2013] [Accepted: 10/07/2013] [Indexed: 12/17/2022] Open
Abstract
OBJECTIVES Pancreatic islet β-cell survival is paramount for regulation of insulin activity and for maintaining glucose homeostasis. Recently, Pax6 has been shown to be essential for many vital functions in β-cells, although many molecular mechanisms of its homeostasis in β-cells remain unclear. The present study investigates novel effects of glucose- and insulin-induced CCCTC-binding factor (CTCF) activity on Pax6 gene expression as well as for subsequent effects of insulin-activated signalling pathways, on β-cell proliferation. MATERIALS AND METHODS Pancreatic β-TC-1-6 cells were cultured in DMEM and stimulated with high concentrations of glucose (5-125 mm); cell viability was assessed by MTT assay. Effects of CTCF on Pax6 were evaluated in the high glucose-induced environment and CTCF/Erk-suppressed cells, by promoter reporter and western blotting analyses. RESULTS Increases in glucose and insulin concentrations upregulated CTCF and consequently downregulated Pax6 in β-cell survival and proliferation. Knocking-down CTCF directly affected Pax6 transcription through CTCF binding and blocked the response to glucose. Altered Erk activity mediated effects of CTCF on controlling Pax6 expression, which partially regulated β-cell proliferation. CONCLUSIONS CTCF functioned as a molecular mediator between insulin-induced upstream Erk signalling and Pax6 expression in these pancreatic β-cells. This pathway may contribute to regulation of β-cell survival and proliferation.
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Affiliation(s)
- S Tsui
- Department of Medicine, David Geffen School of Medicine University of California Los Angeles, Torrance, CA, 90502, USA
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21
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Gosmain Y, Masson MH, Philippe J. Glucagon: the renewal of an old hormone in the pathophysiology of diabetes. J Diabetes 2013; 5:102-9. [PMID: 23302052 DOI: 10.1111/1753-0407.12022] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/04/2012] [Accepted: 12/14/2012] [Indexed: 12/24/2022] Open
Abstract
Type 2 diabetes (T2D) is one of the most common diseases, affecting 5-10% of the population in most countries; the progression of its prevalence has been constant over the past 50 years in all countries worldwide, creating a major public health problem in terms of disease management and financial burden. Although the pathophysiology of T2D has been attributed for decades to insulin resistance and decreased insulin secretion, particularly in response to glucose, the contributing role of glucagon in hyperglycemia has been highlighted since the early 1970s by demonstrating its glycogenolytic, gluconeogenic and ketogenic properties. More recently, the importance of glucagon in diabetes has been highlighted in a model of streptozotocin-induced diabetic mice becoming euglycemic in the absence of glucagon receptors and without insulin treatment. Understanding the dysregulation of α-cells in diabetes will be critical to better define the pathophysiology of diabetes and develop new antidiabetic treatment.
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Affiliation(s)
- Yvan Gosmain
- Service of Endocrinology, Diabetes, Hypertension and Nutrition, University Hospital Geneva, Geneva, Switzerland
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22
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Hara T, Kimura I, Inoue D, Ichimura A, Hirasawa A. Free Fatty Acid Receptors and Their Role in Regulation of Energy Metabolism. Rev Physiol Biochem Pharmacol 2013; 164:77-116. [DOI: 10.1007/112_2013_13] [Citation(s) in RCA: 92] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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