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Chen Y, Hao L, Cong J, Ji J, Dai Y, Xu L, Gong B. Transcriptomic analysis reveals the crosstalk between type 2 diabetes and chronic pancreatitis. Health Sci Rep 2024; 7:e2079. [PMID: 38690006 PMCID: PMC11058262 DOI: 10.1002/hsr2.2079] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2023] [Revised: 03/15/2024] [Accepted: 04/16/2024] [Indexed: 05/02/2024] Open
Abstract
Background and Aims Mounting evidence highlights a strong association between chronic pancreatitis (CP) and type 2 diabetes (T2D), although the exact mechanism of interaction remains unclear. This study aimed to investigate the crosstalk genes and pathogenesis between CP and T2D. Methods Transcriptomic gene expression profiles of CP and T2D were extracted from Gene Expression Omnibus, respectively, and the common differentially expressed genes (DEGs) were subsequently identified. Further analysis, such as Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG), protein-protein interaction, transcription factors (TFs), microRNA (miRNAs), and candidate chemicals identification, was performed to explore the possible common signatures between the two diseases. Results In total, we acquired 281 common DEGs by interacting CP and T2D datasets, and identified 10 hub genes using CytoHubba. GO and KEGG analyses revealed that endoplasmic reticulum stress and mitochondrial dysfunction were closely related to these common DEGs. Among the shared genes, EEF2, DLD, RAB5A, and SLC30A9 showed promising diagnostic value for both diseases based on receiver operating characteristic curve and precision-recall curves. Additionally, we identified 16 key TFs and 16 miRNAs that were strongly correlated with the hub genes, which may serve as new molecular targets for CP and T2D. Finally, candidate chemicals that might become potential drugs for treating CP and T2D were screened out. Conclusion This study provides evidence that there are shared genes and pathological signatures between CP and T2D. The genes EEF2, DLD, RAB5A, and SLC30A9 have been identified as having the highest diagnostic efficiency and could be served as biomarkers for these diseases, providing new insights into precise diagnosis and treatment for CP and T2D.
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Affiliation(s)
- Youlan Chen
- Institute of Integrated Traditional Chinese and Western Medicine Digestive Diseases, Shuguang HospitalShanghai University of Traditional Chinese MedicineShanghaiChina
| | - Lixiao Hao
- Department of Gastroenterology, Shuguang HospitalShanghai University of Traditional Chinese MedicineShanghaiChina
| | - Jun Cong
- Department of Gastroenterology, Shuguang HospitalShanghai University of Traditional Chinese MedicineShanghaiChina
| | - Jianmei Ji
- Department of Gastroenterology, Shuguang HospitalShanghai University of Traditional Chinese MedicineShanghaiChina
| | - Yancheng Dai
- Department of Gastroenterology, Shanghai Traditional Chinese Medicine Integrated HospitalShanghai University of Traditional Chinese MedicineShanghaiChina
| | - Li Xu
- Department of Gastroenterology, Shuguang HospitalShanghai University of Traditional Chinese MedicineShanghaiChina
| | - Biao Gong
- Institute of Integrated Traditional Chinese and Western Medicine Digestive Diseases, Shuguang HospitalShanghai University of Traditional Chinese MedicineShanghaiChina
- Department of Gastroenterology, Shuguang HospitalShanghai University of Traditional Chinese MedicineShanghaiChina
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2
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Moroni-González D, Sarmiento-Ortega VE, Diaz A, Brambila E, Treviño S. Pancreas-Liver-Adipose Axis: Target of Environmental Cadmium Exposure Linked to Metabolic Diseases. TOXICS 2023; 11:223. [PMID: 36976988 PMCID: PMC10059892 DOI: 10.3390/toxics11030223] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/19/2023] [Revised: 02/17/2023] [Accepted: 02/19/2023] [Indexed: 06/18/2023]
Abstract
Cadmium has been well recognized as a critical toxic agent in acute and chronic poisoning cases in occupational and nonoccupational settings and environmental exposure situations. Cadmium is released into the environment after natural and anthropogenic activities, particularly in contaminated and industrial areas, causing food pollution. In the body, cadmium has no biological activity, but it accumulates primarily in the liver and kidney, which are considered the main targets of its toxicity, through oxidative stress and inflammation. However, in the last few years, this metal has been linked to metabolic diseases. The pancreas-liver-adipose axis is largely affected by cadmium accumulation. Therefore, this review aims to collect bibliographic information that establishes the basis for understanding the molecular and cellular mechanisms linked to cadmium with carbohydrate, lipids, and endocrine impairments that contribute to developing insulin resistance, metabolic syndrome, prediabetes, and diabetes.
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Affiliation(s)
- Diana Moroni-González
- Laboratory of Chemical-Clinical Investigations, Department of Clinical Chemistry, Faculty of Chemistry Science, Meritorious Autonomous University of Puebla, Ciudad Universitaria, Puebla 72560, Mexico
| | - Victor Enrique Sarmiento-Ortega
- Laboratory of Chemical-Clinical Investigations, Department of Clinical Chemistry, Faculty of Chemistry Science, Meritorious Autonomous University of Puebla, Ciudad Universitaria, Puebla 72560, Mexico
| | - Alfonso Diaz
- Department of Pharmacy, Faculty of Chemistry Science, Meritorious Autonomous University of Puebla, 22 South. FCQ9, Ciudad Universitaria, Puebla 72560, Mexico
| | - Eduardo Brambila
- Laboratory of Chemical-Clinical Investigations, Department of Clinical Chemistry, Faculty of Chemistry Science, Meritorious Autonomous University of Puebla, Ciudad Universitaria, Puebla 72560, Mexico
| | - Samuel Treviño
- Laboratory of Chemical-Clinical Investigations, Department of Clinical Chemistry, Faculty of Chemistry Science, Meritorious Autonomous University of Puebla, Ciudad Universitaria, Puebla 72560, Mexico
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3
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Hegazy M, El-Shafey M, Abulsoud AI, Elsadek BEM, Abd Elaziz AI, Salama SA. Pioglitazone ameliorates high fat diet-induced hypertension and induces catechol o-methyl transferase expression in rats. Eur J Pharmacol 2020; 885:173383. [PMID: 32750363 DOI: 10.1016/j.ejphar.2020.173383] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2020] [Revised: 06/09/2020] [Accepted: 07/16/2020] [Indexed: 12/28/2022]
Abstract
Our study aimed to investigate the effect of pioglitazone (PIO) on the obesity-associated metabolic effects and whether this effect is associated with modulation of catechol O-methyl transferase (COMT) expression in the high fat diet (HFD) induced obese rats. Male Wistar rats fed HFD were used to evaluate the effect of PIO on obesity-associated hypertension and the expression of COMT. The HFD-induced obesity was confirmed by the change in body weights, the fasting serum insulin (FSI) which assessed by ELISA, homeostasis model assessment - insulin resistance (HOMA-IR), fasting blood glucose (FBG), oral glucose tolerance test (OGTT) and lipid profile which were determined by colorimetric methods. Plasma epinephrine (EP) and norepinephrine (NE) were determined by ELISA and the systolic blood pressure (SBP) was recorded using the tail-cuff method. COMT expression was assessed by quantitative real time-polymerase chain reaction (qRT-PCR), and western blotting. The HFD-induced obesity was associated with glucose intolerance, derangement of the lipid profile, increased SBP, reduced COMT expression with a concomitant increase in plasma catecholamines. Most importantly, treatment with PIO ameliorated the HFD-induced metabolic changes, improved the lipid profile, reduced SBP, increased COMT expression, and reduced plasma catecholamines. Treatment with PIO reversed HFD-induced glucose intolerance and the associated metabolic derangement. In addition, these effects of PIO were associated with up-regulating COMT expression with a subsequent reduction in plasma catecholamines levels.
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Affiliation(s)
- Maghawry Hegazy
- Department of Biochemistry, Faculty of Pharmacy (Boys), Al-Azhar University, Cairo, Egypt.
| | - Mostafa El-Shafey
- Department of Biochemistry, Faculty of Pharmacy (Boys), Al-Azhar University, Cairo, Egypt
| | - Ahmed Ibrahim Abulsoud
- Department of Biochemistry, Faculty of Pharmacy (Boys), Al-Azhar University, Cairo, Egypt; Department of Biochemistry, Faculty of Pharmacy, Heliopolis University, Cairo, Egypt
| | - Bakheet E M Elsadek
- Department of Biochemistry, Faculty of Pharmacy (Boys), Al-Azhar University, Assiut, Egypt
| | - Adel I Abd Elaziz
- Department of Pharmacology, Faculty of Medicine (Boys), Al-Azhar University, Cairo, Egypt
| | - Salama Abdou Salama
- Department of Pharmacology and Toxicology, Faculty of Pharmacy (Boys), Al-Azhar University, Cairo, Egypt
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4
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Sarkar A, Balakrishnan K, Chen J, Patel V, Neelapu SS, McMurray JS, Gandhi V. Molecular evidence of Zn chelation of the procaspase activating compound B-PAC-1 in B cell lymphoma. Oncotarget 2016; 7:3461-76. [PMID: 26658105 PMCID: PMC4823120 DOI: 10.18632/oncotarget.6505] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2015] [Accepted: 11/17/2015] [Indexed: 01/08/2023] Open
Abstract
The resistance of apoptosis in cancer cells is pivotal for their survival and is typically ruled by mutations or dysregulation of core apoptotic cascade. Mantle cell lymphoma (MCL) is a non-Hodgkin's B-cell malignancy expressing higher anti-apoptotic proteins providing survival advantage. B-PAC-1, a procaspase activating compound, induces apoptosis by sequestering Zn bound to procaspase-3, but the amino acids holding Zn in Caspase-3 is not known. Here we show that reintroduction of WT caspase-3 or 7 in Caspase3-7 double knock-out (DKO) mouse embryonic fibroblasts (MEF) promoted B-PAC-1 to induce apoptosis (27-43%), but not in DKO MEFs or MEFs expressing respective Casp3-7 catalytic mutants (12-13%). Using caspase-6 and -9 exosite analysis, we identified and mutated predicted Zn-ligands in caspase-3 (H108A, C148S and E272A) and overexpressed into DKO MEFs. Mutants carrying E272A abrogated Zn-reversal of apoptosis induced by B-PAC-1 via higher XIAP and smac expressions but not in H108A or C148S mutants. Co-immunoprecipitation analysis revealed stronger XIAP-caspase-3 interaction suggesting a novel mechanism of impulsive apoptosis resistance by disrupting predicted Zn-ligands in caspase-3. B-PAC-1 sponsored apoptosis in MCL cell lines (30-73%) via caspase-3 and PARP cleavages accompanied by loss of Mcl-1 and IAPs including XIAP while Zn substantially abrogated B-PAC-1-driven apoptosis (18-36%). In contrary, Zn is dispensable to inhibit staurosporin, bendamustine, ABT199 or MK206-induced apoptosis. Consistent to cell lines, B-PAC-1 stimulated cell death in primary B-lymphoma cells via caspase-3 cleavage with decline in both Mcl-1 and XIAP. This study underscores the first genetic evidence that B-PAC-1 driven apoptosis is mediated via Zn chelation.
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Affiliation(s)
- Aloke Sarkar
- Department of Experimental Therapeutics, The University of Texas Health Science Center, Houston, Texas, USA
| | - Kumudha Balakrishnan
- Department of Experimental Therapeutics, The University of Texas Health Science Center, Houston, Texas, USA.,Department of Leukemia, UT MD Anderson Cancer Center, Houston, Texas, USA.,Graduate School of Biomedical Sciences, The University of Texas Health Science Center, Houston, Texas, USA
| | - Jefferson Chen
- Department of Experimental Therapeutics, The University of Texas Health Science Center, Houston, Texas, USA
| | - Viralkumar Patel
- Department of Experimental Therapeutics, The University of Texas Health Science Center, Houston, Texas, USA
| | - Sattva S Neelapu
- Department of Lymphoma and Myeloma, The University of Texas Health Science Center, Houston, Texas, USA
| | - John S McMurray
- Department of Experimental Therapeutics, The University of Texas Health Science Center, Houston, Texas, USA.,Graduate School of Biomedical Sciences, The University of Texas Health Science Center, Houston, Texas, USA
| | - Varsha Gandhi
- Department of Experimental Therapeutics, The University of Texas Health Science Center, Houston, Texas, USA.,Department of Leukemia, UT MD Anderson Cancer Center, Houston, Texas, USA.,Graduate School of Biomedical Sciences, The University of Texas Health Science Center, Houston, Texas, USA
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5
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Singh V, Saluja N. Phylogenetic and promoter analysis of islet amyloid polypeptide gene causing type 2 diabetes in mammalian species. Int J Diabetes Dev Ctries 2016. [DOI: 10.1007/s13410-016-0508-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
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6
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Glidewell-Kenney CA, Trang C, Shao PP, Gutierrez-Reed N, Uzo-Okereke AM, Coss D, Mellon PL. Neurokinin B induces c-fos transcription via protein kinase C and activation of serum response factor and Elk-1 in immortalized GnRH neurons. Endocrinology 2014; 155:3909-19. [PMID: 25057795 PMCID: PMC4164922 DOI: 10.1210/en.2014-1263] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Mutations in neurokinin B (NKB) and its receptor, NK3R, were identified in human patients with hypogonadotropic hypogonadism, a disorder characterized by lack of puberty and infertility. Further studies have suggested that NKB acts at the level of the hypothalamus to control GnRH neuron activity, either directly or indirectly. We recently reported that treatment with senktide, a NK3R agonist, induced GnRH secretion and expression of c-fos mRNA in GT1-7 cells. Here, we map the responsive region in the murine c-fos promoter to between -400 and -200 bp, identify the signal transducer and activator of transcription (STAT) (-345) and serum response element (-310) sites as required for induction, a modulatory role for the Ets site (-318), and show that induction is protein kinase C dependent. Using gel shift and Gal4 assays, we further show that phosphorylation of Elk-1 leads to binding to DNA in complex with serum response factor at serum response element and Ets sites within the c-fos promoter. Thus, we determine molecular mechanisms involved in NKB regulation of c-fos induction, which may play a role in modulation of GnRH neuron activation.
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Affiliation(s)
- Christine A Glidewell-Kenney
- Department of Reproductive Medicine and the Center for Reproductive Science and Medicine, University of California, San Diego, La Jolla, California 92093-0674
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7
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Luo Y, He F, Hu L, Hai L, Huang M, Xu Z, Zhang J, Zhou Z, Liu F, Dai YS. Transcription factor Ets1 regulates expression of thioredoxin-interacting protein and inhibits insulin secretion in pancreatic β-cells. PLoS One 2014; 9:e99049. [PMID: 24897113 PMCID: PMC4045976 DOI: 10.1371/journal.pone.0099049] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2014] [Accepted: 05/08/2014] [Indexed: 11/18/2022] Open
Abstract
Long-term activation of extracellular-regulated kinase (ERK1/2) pathway has been shown to cause glucotoxicity and inhibit insulin gene expression in β-cells. Transcription factor Ets1 is activated by ERK1/2-mediated phosphorylation at the Thr38 residue. We hypothesize that Ets1 plays an important role in mediating ERK1/2 induced glucotoxicity in β-cells. We determined the role of Ets1 in Min6 cells and isolated mouse islets using overexpression and siRNA mediated knockdown of Ets1. The results show that Ets1 was localized in insulin-staining positive cells but not in glucagon-staining positive cells. Overexpression of Ets1 reduced glucose-stimulated insulin secretion in primary mouse islets. Overexpression of Ets1 in Min6 β-cells and mouse islets increased expression of thioredoxin-interacting protein (TXNIP). Conversely, knockdown of Ets1 by siRNA reduced expression of TXNIP in Min6 cells. Ets1 was associated with the txnip promoter in min6 cells and transfection of 293 cells with Ets1 and p300 synergistically increased txnip promoter reporter activity. Moreover, overexpression of Ets1 inhibited Min6 cell proliferation. Our results suggest that Ets1, by promoting TXNIP expression, negatively regulates β-cell function. Thus, over-activation of Ets1 may contribute to diet-induced β-cell dysfunction.
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Affiliation(s)
- Yan Luo
- Metabolic Syndrome Research Center, Key Laboratory of Diabetes Immunology, Ministry of Education, the Second Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Fengli He
- Metabolic Syndrome Research Center, Key Laboratory of Diabetes Immunology, Ministry of Education, the Second Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Li Hu
- Metabolic Syndrome Research Center, Key Laboratory of Diabetes Immunology, Ministry of Education, the Second Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Luo Hai
- Metabolic Syndrome Research Center, Key Laboratory of Diabetes Immunology, Ministry of Education, the Second Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Meifeng Huang
- Metabolic Syndrome Research Center, Key Laboratory of Diabetes Immunology, Ministry of Education, the Second Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Zhipeng Xu
- Metabolic Syndrome Research Center, Key Laboratory of Diabetes Immunology, Ministry of Education, the Second Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Jingjing Zhang
- Metabolic Syndrome Research Center, Key Laboratory of Diabetes Immunology, Ministry of Education, the Second Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Zhiguang Zhou
- Metabolic Syndrome Research Center, Key Laboratory of Diabetes Immunology, Ministry of Education, the Second Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Feng Liu
- Metabolic Syndrome Research Center, Key Laboratory of Diabetes Immunology, Ministry of Education, the Second Xiangya Hospital, Central South University, Changsha, Hunan, China
- Department of Pharmacology, University of Texas Health Science Center at San Antonio, San Antonio, Texas, United States of America
| | - Yan-Shan Dai
- Metabolic Syndrome Research Center, Key Laboratory of Diabetes Immunology, Ministry of Education, the Second Xiangya Hospital, Central South University, Changsha, Hunan, China
- * E-mail:
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8
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The transcription factor serum response factor stimulates axon regeneration through cytoplasmic localization and cofilin interaction. J Neurosci 2014; 33:18836-48. [PMID: 24285890 DOI: 10.1523/jneurosci.3029-13.2013] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Axonal injury generates growth inert retraction bulbs with dynamic cytoskeletal properties that are severely compromised. Conversion of "frozen" retraction bulbs into actively progressing growth cones is a major aim in axon regeneration. Here we report that murine serum response factor (SRF), a gene regulator linked to the actin cytoskeleton, modulates growth cone actin dynamics during axon regeneration. In regeneration-competent facial motoneurons, Srf deletion inhibited axonal regeneration. In wild-type mice after nerve injury, SRF translocated from the nucleus to the cytoplasm, suggesting a cytoplasmic SRF function in axonal regeneration. Indeed, adenoviral overexpression of cytoplasmic SRF (SRF-ΔNLS-GFP) stimulated axonal sprouting and facial nerve regeneration in vivo. In primary central and peripheral neurons, SRF-ΔNLS-GFP stimulated neurite outgrowth, branch formation, and growth cone morphology. Furthermore, we uncovered a link between SRF and the actin-severing factor cofilin during axonal regeneration in vivo. Facial nerve axotomy increased the total cofilin abundance and also nuclear localization of phosphorylated cofilin in a subpopulation of lesioned motoneurons. This cytoplasmic-to-nucleus translocation of P-cofilin upon axotomy was reduced in motoneurons expressing SRF-ΔNLS-GFP. Finally, we demonstrate that cytoplasmic SRF and cofilin formed a reciprocal regulatory unit. Overexpression of cytoplasmic SRF reduced cofilin phosphorylation and vice versa: overexpression of cofilin inhibited SRF phosphorylation. Therefore, a regulatory loop consisting of SRF and cofilin might take part in reactivating actin dynamics in growth-inert retraction bulbs and facilitating axon regeneration.
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9
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Sabatini PV, Krentz NA, Zarrouki B, Westwell-Roper CY, Nian C, Uy RA, Shapiro AJ, Poitout V, Lynn FC. Npas4 is a novel activity-regulated cytoprotective factor in pancreatic β-cells. Diabetes 2013; 62:2808-20. [PMID: 23656887 PMCID: PMC3717850 DOI: 10.2337/db12-1527] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Cellular homeostasis requires intrinsic sensing mechanisms to temper function in the face of prolonged activity. In the pancreatic β-cell, glucose is likely a physiological trigger that activates an adaptive response to stimulation, thereby maintaining cellular homeostasis. Immediate early genes (IEGs) are activated as a first line of defense in cellular homeostasis and are largely responsible for transmitting an environmental cue to a cellular response. Here we examine the regulation and function of the novel β-cell IEG, neuronal PAS domain protein 4 (Npas4). Using MIN6 cells, mouse and human islets, as well as in vivo infusions, we demonstrate that Npas4 is expressed within pancreatic islets and is upregulated by β-cell depolarizing agents. Npas4 tempers β-cell function through a direct inhibitory interaction with the insulin promoter and by blocking the potentiating effects of GLP-1 without significantly reducing glucose-stimulated secretion. Finally, Npas4 expression is induced by classical endoplasmic reticulum (ER) stressors and can prevent thapsigargin- and palmitate-induced dysfunction and cell death. These results suggest that Npas4 is a key activity-dependent regulator that improves β-cell efficiency in the face of stress. We posit that Npas4 could be a novel therapeutic target in type 2 diabetes that could both reduce ER stress and cell death and maintain basal cell function.
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Affiliation(s)
- Paul V. Sabatini
- Diabetes Research Group, Child and Family Research Institute, Vancouver, British Columbia, Canada
- Department of Surgery and Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, British Columbia, Canada
| | - Nicole A.J. Krentz
- Diabetes Research Group, Child and Family Research Institute, Vancouver, British Columbia, Canada
- Department of Surgery and Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, British Columbia, Canada
| | - Bader Zarrouki
- Montreal Diabetes Research Center, CRCHUM, and Department of Medicine, Université de Montréal, Montréal, Quebec, Canada
| | - Clara Y. Westwell-Roper
- Diabetes Research Group, Child and Family Research Institute, Vancouver, British Columbia, Canada
- Department of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, British Columbia, Canada
| | - Cuilan Nian
- Diabetes Research Group, Child and Family Research Institute, Vancouver, British Columbia, Canada
- Department of Surgery and Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, British Columbia, Canada
| | - Ryan A. Uy
- Diabetes Research Group, Child and Family Research Institute, Vancouver, British Columbia, Canada
| | | | - Vincent Poitout
- Montreal Diabetes Research Center, CRCHUM, and Department of Medicine, Université de Montréal, Montréal, Quebec, Canada
| | - Francis C. Lynn
- Diabetes Research Group, Child and Family Research Institute, Vancouver, British Columbia, Canada
- Department of Surgery and Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, British Columbia, Canada
- Corresponding author: Francis C. Lynn,
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10
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Abstract
Beta cell dysfunction and insulin resistance are inherently complex with their interrelation for triggering the pathogenesis of diabetes also somewhat undefined. Both pathogenic states induce hyperglycemia and therefore increase insulin demand. Beta cell dysfunction results from inadequate glucose sensing to stimulate insulin secretion therefore elevated glucose concentrations prevail. Persistently elevated glucose concentrations above the physiological range result in the manifestation of hyperglycemia. With systemic insulin resistance, insulin signaling within glucose recipient tissues is defective therefore hyperglycemia perseveres. Beta cell dysfunction supersedes insulin resistance in inducing diabetes. Both pathological states influence each other and presumably synergistically exacerbate diabetes. Preserving beta cell function and insulin signaling in beta cells and insulin signaling in the glucose recipient tissues will maintain glucose homeostasis.
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Affiliation(s)
- Marlon E. Cerf
- Diabetes Discovery Platform, South African Medical Research CouncilCape Town, South Africa
- *Correspondence: Marlon E. Cerf, Diabetes Discovery Platform, South African Medical Research Council, PO Box 19070, Tygerberg, Cape Town 7505, South Africa. e-mail:
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11
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Belaguli NS, Zhang M, Brunicardi FC, Berger DH. Forkhead box protein A2 (FOXA2) protein stability and activity are regulated by sumoylation. PLoS One 2012; 7:e48019. [PMID: 23118920 PMCID: PMC3485284 DOI: 10.1371/journal.pone.0048019] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2012] [Accepted: 09/19/2012] [Indexed: 12/29/2022] Open
Abstract
The forkhead box protein A2 (FOXA2) is an important regulator of glucose and lipid metabolism and organismal energy balance. Little is known about how FOXA2 protein expression and activity are regulated by post-translational modifications. We have identified that FOXA2 is post-translationally modified by covalent attachment of a small ubiquitin related modifier-1 (SUMO-1) and mapped the sumoylation site to the amino acid lysine 6 (K6). Preventing sumoylation by mutating the SUMO acceptor K6 to arginine resulted in downregulation of FOXA2 protein but not RNA expression in INS-1E insulinoma cells. K6R mutation also downregulated FOXA2 protein levels in HepG2 hepatocellular carcinoma cells, HCT116 colon cancer cells and LNCaP and DU145 prostate cancer cells. Further, interfering with FOXA2 sumoylation through siRNA mediated knockdown of UBC9, an essential SUMO E2 conjugase, resulted in downregulation of FOXA2 protein levels. Stability of sumoylation deficient FOXA2K6R mutant protein was restored when SUMO-1 was fused in-frame. FOXA2 sumoylation and FOXA2 protein levels were increased by PIAS1 SUMO ligase but not a SUMO ligase activity deficient PIAS1 mutant. Although expressed at lower levels, sumoylation deficient FOXA2K6R mutant protein was detectable in the nucleus indicating that FOXA2 nuclear localization is independent of sumoylation. Sumoylation increased the transcriptional activity of FOXA2 on Pdx-1 area I enhancer. Together, our results show that sumoylation regulates FOXA2 protein expression and activity.
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12
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Müller I, Rössler OG, Wittig C, Menger MD, Thiel G. Critical role of Egr transcription factors in regulating insulin biosynthesis, blood glucose homeostasis, and islet size. Endocrinology 2012; 153:3040-53. [PMID: 22597533 DOI: 10.1210/en.2012-1064] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Expression of early growth response protein (Egr)-1, a protein of the Egr family of zinc finger transcription factors, is stimulated in glucose-treated pancreatic β-cells and insulinoma cells. The purpose of this study was to elucidate the role of Egr transcription factors in pancreatic β-cells in vivo. To overcome the problem associated with redundancy of functions between Egr proteins, conditional transgenic mice were generated expressing a dominant-negative mutant of Egr-1 in pancreatic β-cells. The Egr-1 mutant interferes with DNA binding of all Egr proteins and thus impairs the biological functions of the entire Egr family. Expression of the Egr-1 mutant reduced expression of TGFβ and basic fibroblast growth factor, known target genes of Egr-1, whereas the expression of Egr-1, Egr-3, Ets-like gene-1 (Elk-1), and specificity protein-3 was not changed in the presence of the Egr-1 mutant. Expression of the homeobox protein pancreas duodenum homeobox-1, a major regulator of insulin biosynthesis, was reduced in islets expressing the Egr-1 mutant. Accordingly, insulin mRNA and protein levels were reduced by 75 or 25%, respectively, whereas expression of glucagon and somatostatin was not altered after expression of the Egr-1 mutant in β-cells. Glucose tolerance tests revealed that transgenic mice expressing the Egr-1 mutant in pancreatic β-cells displayed impaired glucose tolerance. In addition, increased caspase-3/7 activity was detected as a result of transgene expression, leading to a 20% decrease of the size of the islets. These results show that Egr proteins play an important role in controlling insulin biosynthesis, glucose homeostasis, and islet size of pancreatic β-cells in vivo.
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Affiliation(s)
- Isabelle Müller
- Department of Medical Biochemistry and Molecular Biology, Building 44, University of Saarland Medical Center, d-66421 Homburg, Germany
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