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Hwang J, Balakrishnan R, Oh E, Veluthakal R, Thurmond DC. A Novel Role for DOC2B in Ameliorating Palmitate-Induced Glucose Uptake Dysfunction in Skeletal Muscle Cells via a Mechanism Involving β-AR Agonism and Cofilin. Int J Mol Sci 2023; 25:137. [PMID: 38203312 PMCID: PMC10779393 DOI: 10.3390/ijms25010137] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2023] [Revised: 12/15/2023] [Accepted: 12/18/2023] [Indexed: 01/12/2024] Open
Abstract
Diet-related lipotoxic stress is a significant driver of skeletal muscle insulin resistance (IR) and type 2 diabetes (T2D) onset. β2-adrenergic receptor (β-AR) agonism promotes insulin sensitivity in vivo under lipotoxic stress conditions. Here, we established an in vitro paradigm of lipotoxic stress using palmitate (Palm) in rat skeletal muscle cells to determine if β-AR agonism could cooperate with double C-2-like domain beta (DOC2B) enrichment to promote skeletal muscle insulin sensitivity under Palm-stress conditions. Previously, human T2D skeletal muscles were shown to be deficient for DOC2B, and DOC2B enrichment resisted IR in vivo. Our Palm-stress paradigm induced IR and β-AR resistance, reduced DOC2B protein levels, triggered cytoskeletal cofilin phosphorylation, and reduced GLUT4 translocation to the plasma membrane (PM). By enhancing DOC2B levels in rat skeletal muscle, we showed that the deleterious effects of palmitate exposure upon cofilin, insulin, and β-AR-stimulated GLUT4 trafficking to the PM and glucose uptake were preventable. In conclusion, we revealed a useful in vitro paradigm of Palm-induced stress to test for factors that can prevent/reverse skeletal muscle dysfunctions related to obesity/pre-T2D. Discerning strategies to enrich DOC2B and promote β-AR agonism can resist skeletal muscle IR and halt progression to T2D.
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Affiliation(s)
- Jinhee Hwang
- Department of Molecular and Cellular Endocrinology, Arthur Riggs Diabetes and Metabolism Research Institute, Beckman Research Institute at City of Hope, Duarte, CA 91010, USA; (J.H.); (R.B.); (E.O.); (R.V.)
- Department of Food and Biotechnology, College of Science and Technology, Korea University, Sejong 30019, Republic of Korea
| | - Rekha Balakrishnan
- Department of Molecular and Cellular Endocrinology, Arthur Riggs Diabetes and Metabolism Research Institute, Beckman Research Institute at City of Hope, Duarte, CA 91010, USA; (J.H.); (R.B.); (E.O.); (R.V.)
| | - Eunjin Oh
- Department of Molecular and Cellular Endocrinology, Arthur Riggs Diabetes and Metabolism Research Institute, Beckman Research Institute at City of Hope, Duarte, CA 91010, USA; (J.H.); (R.B.); (E.O.); (R.V.)
| | - Rajakrishnan Veluthakal
- Department of Molecular and Cellular Endocrinology, Arthur Riggs Diabetes and Metabolism Research Institute, Beckman Research Institute at City of Hope, Duarte, CA 91010, USA; (J.H.); (R.B.); (E.O.); (R.V.)
| | - Debbie C. Thurmond
- Department of Molecular and Cellular Endocrinology, Arthur Riggs Diabetes and Metabolism Research Institute, Beckman Research Institute at City of Hope, Duarte, CA 91010, USA; (J.H.); (R.B.); (E.O.); (R.V.)
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Yu Y, Fu Y, Yu Y, Tang M, Sun Y, Wang Y, Zhang K, Li H, Guo H, Wang B, Wang N, Lu Y. Investigating the shared genetic architecture between schizophrenia and body mass index. Mol Psychiatry 2023; 28:2312-2319. [PMID: 37202504 DOI: 10.1038/s41380-023-02104-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/06/2023] [Revised: 04/28/2023] [Accepted: 05/03/2023] [Indexed: 05/20/2023]
Abstract
Evidence for reciprocal comorbidity of schizophrenia (SCZ) and body mass index (BMI) has grown in recent years. However, little is known regarding the shared genetic architecture or causality underlying the phenotypic association between SCZ and BMI. Leveraging summary statistics from the hitherto largest genome-wide association study (GWAS) on each trait, we investigated the genetic overlap and causal associations of SCZ with BMI. Our study demonstrated a genetic correlation between SCZ and BMI, and the correlation was more evident in local genomic regions. The cross-trait meta-analysis identified 27 significant SNPs shared between SCZ and BMI, most of which had the same direction of influence on both diseases. Mendelian randomization analysis showed the causal association of SCZ with BMI, but not vice versa. Combining the gene expression information, we found that the genetic correlation between SCZ and BMI is enriched in six regions of brain, led by the brain frontal cortex. Additionally, 34 functional genes and 18 specific cell types were found to have an impact on both SCZ and BMI within these regions. Taken together, our comprehensive genome-wide cross-trait analysis suggests a shared genetic basis including pleiotropic loci, tissue enrichment, and shared function genes between SCZ and BMI. This work provides novel insights into the intrinsic genetic overlap of SCZ and BMI, and highlights new opportunities and avenues for future investigation.
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Affiliation(s)
- Yuefeng Yu
- Institute and Department of Endocrinology and Metabolism, Shanghai Ninth People's Hospital, Shanghai JiaoTong University School of Medicine, Shanghai, China
| | - Yanqi Fu
- Institute and Department of Endocrinology and Metabolism, Shanghai Ninth People's Hospital, Shanghai JiaoTong University School of Medicine, Shanghai, China
| | - Yuetian Yu
- Institute and Department of Endocrinology and Metabolism, Shanghai Ninth People's Hospital, Shanghai JiaoTong University School of Medicine, Shanghai, China
| | - Mengjun Tang
- The 967th Hospital of Joint Logistic Support Force of PLA, Dalian, China
| | - Ying Sun
- Institute and Department of Endocrinology and Metabolism, Shanghai Ninth People's Hospital, Shanghai JiaoTong University School of Medicine, Shanghai, China
| | - Yuying Wang
- Institute and Department of Endocrinology and Metabolism, Shanghai Ninth People's Hospital, Shanghai JiaoTong University School of Medicine, Shanghai, China
| | - Kun Zhang
- Institute and Department of Endocrinology and Metabolism, Shanghai Ninth People's Hospital, Shanghai JiaoTong University School of Medicine, Shanghai, China
| | - Huixia Li
- Institute and Department of Endocrinology and Metabolism, Shanghai Ninth People's Hospital, Shanghai JiaoTong University School of Medicine, Shanghai, China
| | - Hui Guo
- Institute and Department of Endocrinology and Metabolism, Shanghai Ninth People's Hospital, Shanghai JiaoTong University School of Medicine, Shanghai, China
| | - Bin Wang
- Institute and Department of Endocrinology and Metabolism, Shanghai Ninth People's Hospital, Shanghai JiaoTong University School of Medicine, Shanghai, China.
| | - Ningjian Wang
- Institute and Department of Endocrinology and Metabolism, Shanghai Ninth People's Hospital, Shanghai JiaoTong University School of Medicine, Shanghai, China.
| | - Yingli Lu
- Institute and Department of Endocrinology and Metabolism, Shanghai Ninth People's Hospital, Shanghai JiaoTong University School of Medicine, Shanghai, China.
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Adiga D, Bhat S, Shukla V, Shah HV, Kuthethur R, Chakrabarty S, Kabekkodu SP. Double C-2 like domain beta (DOC2B) induces calcium dependent oxidative stress to promote lipotoxicity and mitochondrial dysfunction for its tumor suppressive function. Free Radic Biol Med 2023; 201:1-13. [PMID: 36913987 DOI: 10.1016/j.freeradbiomed.2023.03.010] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/03/2022] [Revised: 02/07/2023] [Accepted: 03/07/2023] [Indexed: 03/13/2023]
Abstract
Mitochondria are biosynthetic and bioenergetic organelles that regulate many biological processes, including metabolism, oxidative stress, and cell death. Cervical cancer (CC) cells show impairments in mitochondrial structure and function and are linked with cancer progression. DOC2B is a tumor suppressor with anti-proliferative, anti-migratory, anti-invasive, and anti-metastatic function in CC. For the first time, we demonstrated the role of the DOC2B-mitochondrial axis with tumor growth regulatory functions in CC. We used DOC2B overexpression and knockdown model systems to show that DOC2B is localized to mitochondria and induces Ca2+-mediated lipotoxicity. DOC2B expression induced mitochondrial morphological changes with the subsequent reduction in mitochondrial DNA copy number, mitochondrial mass, and mitochondrial membrane potential. Intracellular and mitochondrial Ca2+, intracellular O.-2, and ATP levels were substantially elevated in the presence of DOC2B. DOC2B manipulation reduced glucose uptake, lactate production, and mitochondrial complex-IV activity. The presence of DOC2B significantly reduced the proteins associated with mitochondrial structure and biogenesis with the concomitant activation of AMPK signaling. Augmented lipid peroxidation (LPO) in the presence of DOC2B was a Ca2+-dependent process. Our findings demonstrated that DOC2B promotes lipid accumulation, oxidative stress, and LPO through intracellular Ca2+ overload, which may contribute to mitochondrial dysfunction and tumor-suppressive properties of DOC2B. We propose that the DOC2B-Ca2+-oxidative stress-LPO-mitochondrial axis could be targeted for confining CC. Further, the induction of lipotoxicity in tumor cells by activating DOC2B could serve as a novel therapeutic approach in CC.
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Affiliation(s)
- Divya Adiga
- Department of Cell and Molecular Biology, Manipal School of Life Sciences, Manipal Academy of Higher Education, Manipal, Karnataka, India
| | - Samatha Bhat
- Department of Cell and Molecular Biology, Manipal School of Life Sciences, Manipal Academy of Higher Education, Manipal, Karnataka, India
| | - Vaibhav Shukla
- Department of Cell and Molecular Biology, Manipal School of Life Sciences, Manipal Academy of Higher Education, Manipal, Karnataka, India
| | - Henil Vinit Shah
- Department of Cell and Molecular Biology, Manipal School of Life Sciences, Manipal Academy of Higher Education, Manipal, Karnataka, India
| | - Raviprasad Kuthethur
- Department of Cell and Molecular Biology, Manipal School of Life Sciences, Manipal Academy of Higher Education, Manipal, Karnataka, India
| | - Sanjiban Chakrabarty
- Department of Cell and Molecular Biology, Manipal School of Life Sciences, Manipal Academy of Higher Education, Manipal, Karnataka, India
| | - Shama Prasada Kabekkodu
- Department of Cell and Molecular Biology, Manipal School of Life Sciences, Manipal Academy of Higher Education, Manipal, Karnataka, India.
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Ding H, Ouyang M, Wang J, Xie M, Huang Y, Yuan F, Jia Y, Zhang X, Liu N, Zhang N. Shared genetics between classes of obesity and psychiatric disorders: A large-scale genome-wide cross-trait analysis. J Psychosom Res 2022; 162:111032. [PMID: 36137488 DOI: 10.1016/j.jpsychores.2022.111032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/11/2022] [Revised: 08/16/2022] [Accepted: 08/31/2022] [Indexed: 10/31/2022]
Abstract
AIMS Epidemiological studies demonstrate an association between classes of obesity and psychiatric disorders, although little is known about shared genetics and causality of association. Thus, we aimed to investigate shared genetics and causal link between different classes of obesity and psychiatric disorders. METHODS We used genome-wide association study (GWAS) summary data range from 9725 to 500,199 sample sizes of European descent, conducted a large-scale genome-wide cross-trait association study to investigate genetic overlap between the classes of obesity and anorexia nervosa, attention-deficit/hyperactivity disorder, autism spectrum disorder, bipolar disorder, major depressive disorder, obsessive-compulsive disorder, schizophrenia, anxiety disorders and Tourette syndrome. We conducted transcriptome-wide association study analysis (TWAS) to identified variants regulated gene expression in those related disorders. Finally, pathway enrichment analysis to identified major pathways. RESULTS In the combined analysis, we replicated 211 previously reported loci and discovered 58 novel independent loci that were associated with all three classes of obesity and related psychiatric disorders. Functional analysis revealed that the identified variants regulated gene expression in major tissues belonging to exocrine/endocrine, digestive, circulatory, adipose, digestive, respiratory, and nervous systems, such as DCC, NEGR1, INO80E. Mendelian randomization analyses suggested that there may be a two-way or one-way causal relationship between obesity and psychiatric disorders. CONCLUSION This large-scale genome-wide cross-trait analysis identified shared genetics and potential causal links between classes of obesity and psychiatric disorders (attention deficit hyperactivity disorder, autism spectrum disorder, anorexia nervosa, major depressive disorder, schizophrenia, and obsessive-compulsive disorder). Such shared genetics suggests potential new biological functions in common among them.
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Affiliation(s)
- Hui Ding
- The Affiliated Nanjing Brain Hospital of Nanjing Medical Univesity, 264 Guangzhou Road, Nanjing, Jiangsu 210029, China
| | - Mengyuan Ouyang
- The Affiliated Nanjing Brain Hospital of Nanjing Medical Univesity, 264 Guangzhou Road, Nanjing, Jiangsu 210029, China
| | - Jinyi Wang
- The Affiliated Nanjing Brain Hospital of Nanjing Medical Univesity, 264 Guangzhou Road, Nanjing, Jiangsu 210029, China
| | - Minyao Xie
- The Affiliated Nanjing Brain Hospital of Nanjing Medical Univesity, 264 Guangzhou Road, Nanjing, Jiangsu 210029, China
| | - Yanyuan Huang
- The Affiliated Nanjing Brain Hospital of Nanjing Medical Univesity, 264 Guangzhou Road, Nanjing, Jiangsu 210029, China
| | - Fangzheng Yuan
- School of Psychology, Nanjing Normal University, Nanjing 210023, China
| | - Yunhan Jia
- School of Psychology, Nanjing Normal University, Nanjing 210023, China
| | - Xuedi Zhang
- The Affiliated Nanjing Brain Hospital of Nanjing Medical Univesity, 264 Guangzhou Road, Nanjing, Jiangsu 210029, China
| | - Na Liu
- The Affiliated Nanjing Brain Hospital of Nanjing Medical Univesity, 264 Guangzhou Road, Nanjing, Jiangsu 210029, China.
| | - Ning Zhang
- The Affiliated Nanjing Brain Hospital of Nanjing Medical Univesity, 264 Guangzhou Road, Nanjing, Jiangsu 210029, China.
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Lasconi C, Pahl MC, Pippin JA, Su C, Johnson ME, Chesi A, Boehm K, Manduchi E, Ou K, Golson ML, Wells AD, Kaestner KH, Grant SFA. Variant-to-gene-mapping analyses reveal a role for pancreatic islet cells in conferring genetic susceptibility to sleep-related traits. Sleep 2022; 45:zsac109. [PMID: 35537191 PMCID: PMC9366645 DOI: 10.1093/sleep/zsac109] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2022] [Revised: 04/24/2022] [Indexed: 12/24/2022] Open
Abstract
We investigated the potential role of sleep-trait associated genetic loci in conferring a degree of their effect via pancreatic α- and β-cells, given that both sleep disturbances and metabolic disorders, including type 2 diabetes and obesity, involve polygenic contributions and complex interactions. We determined genetic commonalities between sleep and metabolic disorders, conducting linkage disequilibrium genetic correlation analyses with publicly available GWAS summary statistics. Then we investigated possible enrichment of sleep-trait associated SNPs in promoter-interacting open chromatin regions within α- and β-cells, intersecting public GWAS reports with our own ATAC-seq and high-resolution promoter-focused Capture C data generated from both sorted human α-cells and an established human beta-cell line (EndoC-βH1). Finally, we identified putative effector genes physically interacting with sleep-trait associated variants in α- and EndoC-βH1cells running variant-to-gene mapping and establish pathways in which these genes are significantly involved. We observed that insomnia, short and long sleep-but not morningness-were significantly correlated with type 2 diabetes, obesity and other metabolic traits. Both the EndoC-βH1 and α-cells were enriched for insomnia loci (p = .01; p = .0076), short sleep loci (p = .017; p = .022) and morningness loci (p = 2.2 × 10-7; p = .0016), while the α-cells were also enriched for long sleep loci (p = .034). Utilizing our promoter contact data, we identified 63 putative effector genes in EndoC-βH1 and 76 putative effector genes in α-cells, with these genes showing significant enrichment for organonitrogen and organophosphate biosynthesis, phosphatidylinositol and phosphorylation, intracellular transport and signaling, stress responses and cell differentiation. Our data suggest that a subset of sleep-related loci confer their effects via cells in pancreatic islets.
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Affiliation(s)
- Chiara Lasconi
- Center for Spatial and Functional Genomics, Children’s Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Matthew C Pahl
- Center for Spatial and Functional Genomics, Children’s Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - James A Pippin
- Center for Spatial and Functional Genomics, Children’s Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Chun Su
- Center for Spatial and Functional Genomics, Children’s Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Matthew E Johnson
- Center for Spatial and Functional Genomics, Children’s Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Alessandra Chesi
- Center for Spatial and Functional Genomics, Children’s Hospital of Philadelphia, Philadelphia, PA 19104, USA
- Department of Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Keith Boehm
- Center for Spatial and Functional Genomics, Children’s Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Elisabetta Manduchi
- Institute for Biomedical Informatics, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA,USA
| | - Kristy Ou
- Department of Genetics, University of Pennsylvania, Philadelphia, PA 19104, USA
- Institute for Diabetes, Obesity and Metabolism, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Maria L Golson
- Department of Genetics, University of Pennsylvania, Philadelphia, PA 19104, USA
- Institute for Diabetes, Obesity and Metabolism, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Andrew D Wells
- Center for Spatial and Functional Genomics, Children’s Hospital of Philadelphia, Philadelphia, PA 19104, USA
- Department of Pathology and Laboratory Medicine, Children’s Hospital of Philadelphia, Philadelphia, PA, USA
| | - Klaus H Kaestner
- Department of Genetics, University of Pennsylvania, Philadelphia, PA 19104, USA
- Institute for Diabetes, Obesity and Metabolism, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Struan F A Grant
- Center for Spatial and Functional Genomics, Children’s Hospital of Philadelphia, Philadelphia, PA 19104, USA
- Department of Genetics, University of Pennsylvania, Philadelphia, PA 19104, USA
- Institute for Diabetes, Obesity and Metabolism, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
- Department of Pediatrics, The University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
- Division of Human Genetics, Children’s Hospital of Philadelphia, Philadelphia, PA 19104, USA
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Hwang J, Thurmond DC. Exocytosis Proteins: Typical and Atypical Mechanisms of Action in Skeletal Muscle. Front Endocrinol (Lausanne) 2022; 13:915509. [PMID: 35774142 PMCID: PMC9238359 DOI: 10.3389/fendo.2022.915509] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/08/2022] [Accepted: 05/11/2022] [Indexed: 11/18/2022] Open
Abstract
Insulin-stimulated glucose uptake in skeletal muscle is of fundamental importance to prevent postprandial hyperglycemia, and long-term deficits in insulin-stimulated glucose uptake underlie insulin resistance and type 2 diabetes. Skeletal muscle is responsible for ~80% of the peripheral glucose uptake from circulation via the insulin-responsive glucose transporter GLUT4. GLUT4 is mainly sequestered in intracellular GLUT4 storage vesicles in the basal state. In response to insulin, the GLUT4 storage vesicles rapidly translocate to the plasma membrane, where they undergo vesicle docking, priming, and fusion via the high-affinity interactions among the soluble N-ethylmaleimide sensitive factor attachment protein receptor (SNARE) exocytosis proteins and their regulators. Numerous studies have elucidated that GLUT4 translocation is defective in insulin resistance and type 2 diabetes. Emerging evidence also links defects in several SNAREs and SNARE regulatory proteins to insulin resistance and type 2 diabetes in rodents and humans. Therefore, we highlight the latest research on the role of SNAREs and their regulatory proteins in insulin-stimulated GLUT4 translocation in skeletal muscle. Subsequently, we discuss the novel emerging role of SNARE proteins as interaction partners in pathways not typically thought to involve SNAREs and how these atypical functions reveal novel therapeutic targets for combating peripheral insulin resistance and diabetes.
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Affiliation(s)
| | - Debbie C. Thurmond
- Department of Molecular and Cellular Endocrinology, Arthur Riggs Diabetes and Metabolism Research Institute, Beckman Research Institute at City of Hope, Duarte, CA, United States
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Chatterjee Bhowmick D, Aslamy A, Bhattacharya S, Oh E, Ahn M, Thurmond DC. DOC2b Enhances β-Cell Function via a Novel Tyrosine Phosphorylation-Dependent Mechanism. Diabetes 2022; 71:1246-1260. [PMID: 35377441 PMCID: PMC9163558 DOI: 10.2337/db21-0681] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/02/2021] [Accepted: 03/13/2022] [Indexed: 11/13/2022]
Abstract
Double C2 domain Β (DOC2b) protein is required for glucose-stimulated insulin secretion (GSIS) in β-cells, the underlying mechanism of which remains unresolved. Our biochemical analysis using primary human islets and human and rodent clonal β-cells revealed that DOC2b is tyrosine phosphorylated within 2 min of glucose stimulation, and Src family kinase member YES is required for this process. Biochemical and functional analysis using DOC2bY301 mutants revealed the requirement of Y301 phosphorylation for the interaction of DOC2b with YES kinase and increased content of VAMP2, a protein on insulin secretory granules, at the plasma membrane (PM), concomitant with DOC2b-mediated enhancement of GSIS in β-cells. Coimmunoprecipitation studies demonstrated an increased association of DOC2b with ERM family proteins in β-cells following glucose stimulation or pervanadate treatment. Y301 phosphorylation-competent DOC2b was required to increase ERM protein activation, and ERM protein knockdown impaired DOC2b-mediated boosting of GSIS, suggesting that tyrosine-phosphorylated DOC2b regulates GSIS via ERM-mediated granule localization to the PM. Taken together, these results demonstrate the glucose-induced posttranslational modification of DOC2b in β-cells, pinpointing the kinase, site of action, and downstream signaling events and revealing a regulatory role of YES kinase at various steps in GSIS. This work will enhance the development of novel therapeutic strategies to restore glucose homeostasis in diabetes.
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Affiliation(s)
- Diti Chatterjee Bhowmick
- Department of Molecular and Cellular Endocrinology, Diabetes and Metabolic Research Institute, Beckman Research Institute of City of Hope, Duarte, CA
| | - Arianne Aslamy
- Department of Medicine, Cedars-Sinai Medical Center, West Hollywood, CA
| | | | - Eunjin Oh
- Department of Molecular and Cellular Endocrinology, Diabetes and Metabolic Research Institute, Beckman Research Institute of City of Hope, Duarte, CA
| | - Miwon Ahn
- Department of Molecular and Cellular Endocrinology, Diabetes and Metabolic Research Institute, Beckman Research Institute of City of Hope, Duarte, CA
| | - Debbie C. Thurmond
- Department of Molecular and Cellular Endocrinology, Diabetes and Metabolic Research Institute, Beckman Research Institute of City of Hope, Duarte, CA
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8
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Conventional and Unconventional Mechanisms by which Exocytosis Proteins Oversee β-cell Function and Protection. Int J Mol Sci 2021; 22:ijms22041833. [PMID: 33673206 PMCID: PMC7918544 DOI: 10.3390/ijms22041833] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2021] [Revised: 02/02/2021] [Accepted: 02/08/2021] [Indexed: 02/06/2023] Open
Abstract
Type 2 diabetes (T2D) is one of the prominent causes of morbidity and mortality in the United States and beyond, reaching global pandemic proportions. One hallmark of T2D is dysfunctional glucose-stimulated insulin secretion from the pancreatic β-cell. Insulin is secreted via the recruitment of insulin secretory granules to the plasma membrane, where the soluble N-ethylmaleimide-sensitive factor attachment protein receptors (SNAREs) and SNARE regulators work together to dock the secretory granules and release insulin into the circulation. SNARE proteins and their regulators include the Syntaxins, SNAPs, Sec1/Munc18, VAMPs, and double C2-domain proteins. Recent studies using genomics, proteomics, and biochemical approaches have linked deficiencies of exocytosis proteins with the onset and progression of T2D. Promising results are also emerging wherein restoration or enhancement of certain exocytosis proteins to β-cells improves whole-body glucose homeostasis, enhances β-cell function, and surprisingly, protection of β-cell mass. Intriguingly, overexpression and knockout studies have revealed novel functions of certain exocytosis proteins, like Syntaxin 4, suggesting that exocytosis proteins can impact a variety of pathways, including inflammatory signaling and aging. In this review, we present the conventional and unconventional functions of β-cell exocytosis proteins in normal physiology and T2D and describe how these insights might improve clinical care for T2D.
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9
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Dunn LL, Kong SMY, Tumanov S, Chen W, Cantley J, Ayer A, Maghzal GJ, Midwinter RG, Chan KH, Ng MKC, Stocker R. Hmox1 (Heme Oxygenase-1) Protects Against Ischemia-Mediated Injury via Stabilization of HIF-1α (Hypoxia-Inducible Factor-1α). Arterioscler Thromb Vasc Biol 2021; 41:317-330. [PMID: 33207934 DOI: 10.1161/atvbaha.120.315393] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
OBJECTIVE Hmox1 (heme oxygenase-1) is a stress-induced enzyme that catalyzes the degradation of heme to carbon monoxide, iron, and biliverdin. Induction of Hmox1 and its products protect against cardiovascular disease, including ischemic injury. Hmox1 is also a downstream target of the transcription factor HIF-1α (hypoxia-inducible factor-1α), a key regulator of the body's response to hypoxia. However, the mechanisms by which Hmox1 confers protection against ischemia-mediated injury remain to be fully understood. Approach and Results: Hmox1 deficient (Hmox1-/-) mice had impaired blood flow recovery with severe tissue necrosis and autoamputation following unilateral hindlimb ischemia. Autoamputation preceded the return of blood flow, and bone marrow transfer from littermate wild-type mice failed to prevent tissue injury and autoamputation. In wild-type mice, ischemia-induced expression of Hmox1 in skeletal muscle occurred before stabilization of HIF-1α. Moreover, HIF-1α stabilization and glucose utilization were impaired in Hmox1-/- mice compared with wild-type mice. Experiments exposing dermal fibroblasts to hypoxia (1% O2) recapitulated these key findings. Metabolomics analyses indicated a failure of Hmox1-/- mice to adapt cellular energy reprogramming in response to ischemia. Prolyl-4-hydroxylase inhibition stabilized HIF-1α in Hmox1-/- fibroblasts and ischemic skeletal muscle, decreased tissue necrosis and autoamputation, and restored cellular metabolism to that of wild-type mice. Mechanistic studies showed that carbon monoxide stabilized HIF-1α in Hmox1-/- fibroblasts in response to hypoxia. CONCLUSIONS Our findings suggest that Hmox1 acts both downstream and upstream of HIF-1α, and that stabilization of HIF-1α contributes to Hmox1's protection against ischemic injury independent of neovascularization.
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Affiliation(s)
- Louise L Dunn
- The Victor Chang Cardiac Research Institute, Darlinghurst, NSW, Australia (L.L.D., S.M.Y.K., S.T., W.C., A.A., G.J.M., R.S.)
- St Vincent's Clinical School, University of New South Wales, Sydney, Australia (L.L.D., W.C., A.A., G.J.M., R.S.)
| | - Stephanie M Y Kong
- The Victor Chang Cardiac Research Institute, Darlinghurst, NSW, Australia (L.L.D., S.M.Y.K., S.T., W.C., A.A., G.J.M., R.S.)
| | - Sergey Tumanov
- The Victor Chang Cardiac Research Institute, Darlinghurst, NSW, Australia (L.L.D., S.M.Y.K., S.T., W.C., A.A., G.J.M., R.S.)
- Heart Research Institute, Newtown, NSW, Australia (S.T., W.C., A.A., K.H.C., M.K.C.N., R.S.)
| | - Weiyu Chen
- The Victor Chang Cardiac Research Institute, Darlinghurst, NSW, Australia (L.L.D., S.M.Y.K., S.T., W.C., A.A., G.J.M., R.S.)
- St Vincent's Clinical School, University of New South Wales, Sydney, Australia (L.L.D., W.C., A.A., G.J.M., R.S.)
- Heart Research Institute, Newtown, NSW, Australia (S.T., W.C., A.A., K.H.C., M.K.C.N., R.S.)
| | | | - Anita Ayer
- The Victor Chang Cardiac Research Institute, Darlinghurst, NSW, Australia (L.L.D., S.M.Y.K., S.T., W.C., A.A., G.J.M., R.S.)
- St Vincent's Clinical School, University of New South Wales, Sydney, Australia (L.L.D., W.C., A.A., G.J.M., R.S.)
- Heart Research Institute, Newtown, NSW, Australia (S.T., W.C., A.A., K.H.C., M.K.C.N., R.S.)
| | - Ghassan J Maghzal
- The Victor Chang Cardiac Research Institute, Darlinghurst, NSW, Australia (L.L.D., S.M.Y.K., S.T., W.C., A.A., G.J.M., R.S.)
- St Vincent's Clinical School, University of New South Wales, Sydney, Australia (L.L.D., W.C., A.A., G.J.M., R.S.)
| | - Robyn G Midwinter
- St Vincent's Clinical School, University of New South Wales, Sydney, Australia (L.L.D., W.C., A.A., G.J.M., R.S.)
- Centre for Vascular Research, School of Medical Sciences (Pathology), and Bosch Institute, Sydney Medical School, The University of Sydney, Australia (R.G.M., R.S.)
| | - Kim H Chan
- Heart Research Institute, Newtown, NSW, Australia (S.T., W.C., A.A., K.H.C., M.K.C.N., R.S.)
- Royal Prince Alfred Hospital, Camperdown, NSW, Australia (K.H.C., M.K.C.N.)
| | - Martin K C Ng
- Heart Research Institute, Newtown, NSW, Australia (S.T., W.C., A.A., K.H.C., M.K.C.N., R.S.)
- Royal Prince Alfred Hospital, Camperdown, NSW, Australia (K.H.C., M.K.C.N.)
| | - Roland Stocker
- The Victor Chang Cardiac Research Institute, Darlinghurst, NSW, Australia (L.L.D., S.M.Y.K., S.T., W.C., A.A., G.J.M., R.S.)
- Heart Research Institute, Newtown, NSW, Australia (S.T., W.C., A.A., K.H.C., M.K.C.N., R.S.)
- Centre for Vascular Research, School of Medical Sciences (Pathology), and Bosch Institute, Sydney Medical School, The University of Sydney, Australia (R.G.M., R.S.)
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10
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Bradberry MM, Bao H, Lou X, Chapman ER. Phosphatidylinositol 4,5-bisphosphate drives Ca 2+-independent membrane penetration by the tandem C2 domain proteins synaptotagmin-1 and Doc2β. J Biol Chem 2019; 294:10942-10953. [PMID: 31147445 DOI: 10.1074/jbc.ra119.007929] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2019] [Revised: 05/28/2019] [Indexed: 12/14/2022] Open
Abstract
Exocytosis mediates the release of neurotransmitters and hormones from neurons and neuroendocrine cells. Tandem C2 domain proteins in the synaptotagmin (syt) and double C2 domain (Doc2) families regulate exocytotic membrane fusion via direct interactions with Ca2+ and phospholipid bilayers. Syt1 is a fast-acting, low-affinity Ca2+ sensor that penetrates membranes upon binding Ca2+ to trigger synchronous vesicle fusion. The closely related Doc2β is a slow-acting, high-affinity Ca2+ sensor that triggers spontaneous and asynchronous vesicle fusion, but whether it also penetrates membranes is unknown. Both syt1 and Doc2β bind the dynamically regulated plasma membrane lipid phosphatidylinositol 4,5-bisphosphate (PIP2), but it is unclear whether PIP2 serves only as a membrane contact or enables specialized membrane-binding modes by these Ca2+ sensors. Furthermore, it has been shown that PIP2 uncaging can trigger rapid, syt1-dependent exocytosis in the absence of Ca2+ influx, suggesting that current models for the action of these Ca2+ sensors are incomplete. Here, using a series of steady-state and time-resolved fluorescence measurements, we show that Doc2β, like syt1, penetrates membranes in a Ca2+-dependent manner. Unexpectedly, we observed that PIP2 can drive membrane penetration by both syt1 and Doc2β in the absence of Ca2+, providing a plausible mechanism for Ca2+-independent, PIP2-dependent exocytosis. Quantitative measurements of penetration depth revealed that, in the presence of Ca2+, PIP2 drives Doc2β, but not syt1, substantially deeper into the membrane, defining a biophysical regulatory mechanism specific to this high-affinity Ca2+ sensor. Our results provide evidence of a novel role for PIP2 in regulating, and under some circumstances triggering, exocytosis.
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Affiliation(s)
- Mazdak M Bradberry
- Howard Hughes Medical Institute and the Department of Neuroscience, School of Medicine and Public Health, University of Wisconsin, Madison, Wisconsin 53706 and; Medical Scientist Training Program, School of Medicine and Public Health, University of Wisconsin, Madison, Wisconsin 53705
| | - Huan Bao
- Howard Hughes Medical Institute and the Department of Neuroscience, School of Medicine and Public Health, University of Wisconsin, Madison, Wisconsin 53706 and
| | - Xiaochu Lou
- Howard Hughes Medical Institute and the Department of Neuroscience, School of Medicine and Public Health, University of Wisconsin, Madison, Wisconsin 53706 and
| | - Edwin R Chapman
- Howard Hughes Medical Institute and the Department of Neuroscience, School of Medicine and Public Health, University of Wisconsin, Madison, Wisconsin 53706 and.
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11
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Nomiyama R, Emoto M, Fukuda N, Matsui K, Kondo M, Sakane A, Sasaki T, Tanizawa Y. Protein kinase C iota facilitates insulin-induced glucose transport by phosphorylation of soluble nSF attachment protein receptor regulator (SNARE) double C2 domain protein b. J Diabetes Investig 2019; 10:591-601. [PMID: 30369065 PMCID: PMC6497606 DOI: 10.1111/jdi.12965] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/25/2018] [Revised: 09/25/2018] [Accepted: 10/11/2018] [Indexed: 12/24/2022] Open
Abstract
AIMS/INTRODUCTION Double C2 domain protein b (DOC2b), one of the synaptotagmins, has been shown to translocate to the plasma membrane, and to initiate membrane-fusion processes of vesicles containing glucose transporter 4 proteins on insulin stimulation. However, the mechanism by which DOC2b is regulated remains unclear. Herein, we identified the upstream regulatory factors of DOC2b in insulin signal transduction. We also examined the role of DOC2b on systemic homeostasis using DOC2b knockout (KO) mice. MATERIALS AND METHODS We first identified DOC2b binding proteins by immunoprecipitation and mutagenesis experiments. Then, DOC2b KO mice were generated by disrupting the first exon of the DOC2b gene. In addition to the histological examination, glucose metabolism was assessed by measuring parameters on glucose/insulin tolerance tests. Insulin-stimulated glucose uptake was also measured using isolated soleus muscle and epididymal adipose tissue. RESULTS We identified an isoform of atypical protein kinase C (protein kinase C iota) that can bind to DOC2b and phosphorylates one of the serine residues of DOC2b (S34). This phosphorylation is essential for DOC2b translocation. DOC2b KO mice showed insulin resistance and impaired oral glucose tolerance on insulin and glucose tolerance tests, respectively. Insulin-stimulated glucose uptake was impaired in isolated soleus muscle and epididymal adipose tissues from DOC2b KO mice. CONCLUSIONS We propose a novel insulin signaling mechanism by which protein kinase C iota phosphorylates DOC2b, leading to glucose transporter 4 vesicle translocation, fusion and facilitation of glucose uptake in response to insulin. The present results also showed DOC2b to play important roles in systemic glucose homeostasis.
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Affiliation(s)
- Ryuta Nomiyama
- Division of Endocrinology, Metabolism, Hematological Sciences and TherapeuticsYamaguchi University Graduate School of MedicineUbeJapan
| | - Masahiro Emoto
- Division of Endocrinology, Metabolism, Hematological Sciences and TherapeuticsYamaguchi University Graduate School of MedicineUbeJapan
- Emoto ClinicUbeJapan
| | - Naofumi Fukuda
- Division of Endocrinology, Metabolism, Hematological Sciences and TherapeuticsYamaguchi University Graduate School of MedicineUbeJapan
| | - Kumiko Matsui
- Division of Endocrinology, Metabolism, Hematological Sciences and TherapeuticsYamaguchi University Graduate School of MedicineUbeJapan
| | - Manabu Kondo
- Division of Endocrinology, Metabolism, Hematological Sciences and TherapeuticsYamaguchi University Graduate School of MedicineUbeJapan
| | - Ayuko Sakane
- Department of BiochemistryTokushima University Graduate School of Medical SciencesTokushimaJapan
| | - Takuya Sasaki
- Department of BiochemistryTokushima University Graduate School of Medical SciencesTokushimaJapan
| | - Yukio Tanizawa
- Division of Endocrinology, Metabolism, Hematological Sciences and TherapeuticsYamaguchi University Graduate School of MedicineUbeJapan
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12
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Zhang J, Oh E, Merz KE, Aslamy A, Veluthakal R, Salunkhe VA, Ahn M, Tunduguru R, Thurmond DC. DOC2B promotes insulin sensitivity in mice via a novel KLC1-dependent mechanism in skeletal muscle. Diabetologia 2019; 62:845-859. [PMID: 30707251 PMCID: PMC6451670 DOI: 10.1007/s00125-019-4824-2] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/25/2018] [Accepted: 12/14/2018] [Indexed: 12/11/2022]
Abstract
AIMS/HYPOTHESIS Skeletal muscle accounts for >80% of insulin-stimulated glucose uptake; dysfunction of this process underlies insulin resistance and type 2 diabetes. Insulin sensitivity is impaired in mice deficient in the double C2 domain β (DOC2B) protein, while whole-body overexpression of DOC2B enhances insulin sensitivity. Whether insulin sensitivity in the skeletal muscle is affected directly by DOC2B or is secondary to an effect on other tissues is unknown; the underlying molecular mechanisms also remain unclear. METHODS Human skeletal muscle samples from non-diabetic or type 2 diabetic donors were evaluated for loss of DOC2B during diabetes development. For in vivo analysis, new doxycycline-inducible skeletal-muscle-specific Doc2b-overexpressing mice fed standard or high-fat diets were evaluated for insulin and glucose tolerance, and insulin-stimulated GLUT4 accumulation at the plasma membrane (PM). For in vitro analyses, a DOC2B-overexpressing L6-GLUT4-myc myoblast/myotube culture system was coupled with an insulin resistance paradigm. Biochemical and molecular biology methods such as site-directed mutagenesis, co-immunoprecipitation and mass spectrometry were used to identify the molecular mechanisms linking insulin stimulation to DOC2B. RESULTS We identified loss of DOC2B (55% reduction in RNA and 40% reduction in protein) in the skeletal muscle of human donors with type 2 diabetes. Furthermore, inducible enrichment of DOC2B in skeletal muscle of transgenic mice enhanced whole-body glucose tolerance (AUC decreased by 25% for female mice) and peripheral insulin sensitivity (area over the curve increased by 20% and 26% for female and male mice, respectively) in vivo, underpinned by enhanced insulin-stimulated GLUT4 accumulation at the PM. Moreover, DOC2B enrichment in skeletal muscle protected mice from high-fat-diet-induced peripheral insulin resistance, despite the persistence of obesity. In L6-GLUT4-myc myoblasts, DOC2B enrichment was sufficient to preserve normal insulin-stimulated GLUT4 accumulation at the PM in cells exposed to diabetogenic stimuli. We further identified that DOC2B is phosphorylated on insulin stimulation, enhancing its interaction with a microtubule motor protein, kinesin light chain 1 (KLC1). Mutation of Y301 in DOC2B blocked the insulin-stimulated phosphorylation of DOC2B and interaction with KLC1, and it blunted the ability of DOC2B to enhance insulin-stimulated GLUT4 accumulation at the PM. CONCLUSIONS/INTERPRETATION These results suggest that DOC2B collaborates with KLC1 to regulate insulin-stimulated GLUT4 accumulation at the PM and regulates insulin sensitivity. Our observation provides a basis for pursuing DOC2B as a novel drug target in the muscle to prevent/treat type 2 diabetes.
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Affiliation(s)
- Jing Zhang
- Department of Molecular and Cellular Endocrinology, Diabetes and Metabolism Research Institute, Beckman Research Institute of City of Hope, 1500 E. Duarte Road, Duarte, CA, 91010, USA
- Anwita Biosciences Inc, San Carlos, CA, USA
| | - Eunjin Oh
- Department of Molecular and Cellular Endocrinology, Diabetes and Metabolism Research Institute, Beckman Research Institute of City of Hope, 1500 E. Duarte Road, Duarte, CA, 91010, USA
| | - Karla E Merz
- Department of Molecular and Cellular Endocrinology, Diabetes and Metabolism Research Institute, Beckman Research Institute of City of Hope, 1500 E. Duarte Road, Duarte, CA, 91010, USA
| | - Arianne Aslamy
- Department of Molecular and Cellular Endocrinology, Diabetes and Metabolism Research Institute, Beckman Research Institute of City of Hope, 1500 E. Duarte Road, Duarte, CA, 91010, USA
- Department of Cellular and Integrative Physiology, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Rajakrishnan Veluthakal
- Department of Molecular and Cellular Endocrinology, Diabetes and Metabolism Research Institute, Beckman Research Institute of City of Hope, 1500 E. Duarte Road, Duarte, CA, 91010, USA
| | - Vishal A Salunkhe
- Department of Molecular and Cellular Endocrinology, Diabetes and Metabolism Research Institute, Beckman Research Institute of City of Hope, 1500 E. Duarte Road, Duarte, CA, 91010, USA
| | - Miwon Ahn
- Department of Molecular and Cellular Endocrinology, Diabetes and Metabolism Research Institute, Beckman Research Institute of City of Hope, 1500 E. Duarte Road, Duarte, CA, 91010, USA
| | - Ragadeepthi Tunduguru
- Department of Molecular and Cellular Endocrinology, Diabetes and Metabolism Research Institute, Beckman Research Institute of City of Hope, 1500 E. Duarte Road, Duarte, CA, 91010, USA
- Department of Diabetes Complications and Metabolism, Diabetes and Metabolism Research Institute, Beckman Research Institute of City of Hope, Duarte, CA, USA
| | - Debbie C Thurmond
- Department of Molecular and Cellular Endocrinology, Diabetes and Metabolism Research Institute, Beckman Research Institute of City of Hope, 1500 E. Duarte Road, Duarte, CA, 91010, USA.
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13
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Aslamy A, Oh E, Olson EM, Zhang J, Ahn M, Moin ASM, Tunduguru R, Salunkhe VA, Veluthakal R, Thurmond DC. Doc2b Protects β-Cells Against Inflammatory Damage and Enhances Function. Diabetes 2018; 67:1332-1344. [PMID: 29661782 PMCID: PMC6014558 DOI: 10.2337/db17-1352] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/07/2017] [Accepted: 04/09/2018] [Indexed: 12/12/2022]
Abstract
Loss of functional β-cell mass is an early feature of type 1 diabetes. To release insulin, β-cells require soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) complexes, as well as SNARE complex regulatory proteins like double C2 domain-containing protein β (Doc2b). We hypothesized that Doc2b deficiency or overabundance may confer susceptibility or protection, respectively, to the functional β-cell mass. Indeed, Doc2b+/- knockout mice show an unusually severe response to multiple-low-dose streptozotocin (MLD-STZ), resulting in more apoptotic β-cells and a smaller β-cell mass. In addition, inducible β-cell-specific Doc2b-overexpressing transgenic (βDoc2b-dTg) mice show improved glucose tolerance and resist MLD-STZ-induced disruption of glucose tolerance, fasting hyperglycemia, β-cell apoptosis, and loss of β-cell mass. Mechanistically, Doc2b enrichment enhances glucose-stimulated insulin secretion (GSIS) and SNARE activation and prevents the appearance of apoptotic markers in response to cytokine stress and thapsigargin. Furthermore, expression of a peptide containing the Doc2b tandem C2A and C2B domains is sufficient to confer the beneficial effects of Doc2b enrichment on GSIS, SNARE activation, and apoptosis. These studies demonstrate that Doc2b enrichment in the β-cell protects against diabetogenic and proapoptotic stress. Furthermore, they identify a Doc2b peptide that confers the beneficial effects of Doc2b and may be a therapeutic candidate for protecting functional β-cell mass.
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Affiliation(s)
- Arianne Aslamy
- Department of Molecular and Cellular Endocrinology, Diabetes and Metabolic Research Institute, Beckman Research Institute of City of Hope, Duarte, CA
- Department of Cellular and Integrative Physiology, Indiana University School of Medicine, Indianapolis, IN
| | - Eunjin Oh
- Department of Molecular and Cellular Endocrinology, Diabetes and Metabolic Research Institute, Beckman Research Institute of City of Hope, Duarte, CA
| | - Erika M Olson
- Department of Molecular and Cellular Endocrinology, Diabetes and Metabolic Research Institute, Beckman Research Institute of City of Hope, Duarte, CA
| | - Jing Zhang
- Department of Molecular and Cellular Endocrinology, Diabetes and Metabolic Research Institute, Beckman Research Institute of City of Hope, Duarte, CA
| | - Miwon Ahn
- Department of Molecular and Cellular Endocrinology, Diabetes and Metabolic Research Institute, Beckman Research Institute of City of Hope, Duarte, CA
| | - Abu Saleh Md Moin
- Department of Molecular and Cellular Endocrinology, Diabetes and Metabolic Research Institute, Beckman Research Institute of City of Hope, Duarte, CA
| | - Ragadeepthi Tunduguru
- Department of Molecular and Cellular Endocrinology, Diabetes and Metabolic Research Institute, Beckman Research Institute of City of Hope, Duarte, CA
- Department of Diabetes Complications and Metabolism, Diabetes and Metabolic Research Institute, Beckman Research Institute of City of Hope, Duarte, CA
| | - Vishal A Salunkhe
- Department of Molecular and Cellular Endocrinology, Diabetes and Metabolic Research Institute, Beckman Research Institute of City of Hope, Duarte, CA
| | - Rajakrishnan Veluthakal
- Department of Molecular and Cellular Endocrinology, Diabetes and Metabolic Research Institute, Beckman Research Institute of City of Hope, Duarte, CA
| | - Debbie C Thurmond
- Department of Molecular and Cellular Endocrinology, Diabetes and Metabolic Research Institute, Beckman Research Institute of City of Hope, Duarte, CA
- Department of Cellular and Integrative Physiology, Indiana University School of Medicine, Indianapolis, IN
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14
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Aslamy A, Oh E, Ahn M, Moin ASM, Chang M, Duncan M, Hacker-Stratton J, El-Shahawy M, Kandeel F, DiMeglio LA, Thurmond DC. Exocytosis Protein DOC2B as a Biomarker of Type 1 Diabetes. J Clin Endocrinol Metab 2018; 103:1966-1976. [PMID: 29506054 PMCID: PMC6276681 DOI: 10.1210/jc.2017-02492] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/17/2017] [Accepted: 02/26/2018] [Indexed: 12/20/2022]
Abstract
CONTEXT Efforts to preserve β-cell mass in the preclinical stages of type 1 diabetes (T1D) are limited by few blood-derived biomarkers of β-cell destruction. OBJECTIVE Platelets are proposed sources of blood-derived biomarkers for a variety of diseases, and they show distinct proteomic changes in T1D. Thus, we investigated changes in the exocytosis protein, double C2 domain protein-β (DOC2B) in platelets and islets from T1D humans, and prediabetic nonobese diabetic (NOD) mice. DESIGN, PATIENTS, AND MAIN OUTCOME MEASURE Protein levels of DOC2B were assessed in platelets and islets from prediabetic NOD mice and humans, with and without T1D. Seventeen new-onset T1D human subjects (10.3 ± 3.8 years) were recruited immediately following diagnosis, and platelet DOC2B levels were compared with 14 matched nondiabetic subjects (11.4 ± 2.9 years). Furthermore, DOC2B levels were assessed in T1D human pancreatic tissue samples, cytokine-stimulated human islets ex vivo, and platelets from T1D subjects before and after islet transplantation. RESULTS DOC2B protein abundance was substantially reduced in prediabetic NOD mouse platelets, and these changes were mirrored in the pancreatic islets from the same mice. Likewise, human DOC2B levels were reduced over twofold in platelets from new-onset T1D human subjects, and this reduction was mirrored in T1D human islets. Cytokine stimulation of normal islets reduced DOC2B expression ex vivo. Remarkably, platelet DOC2B levels increased after islet transplantation in patients with T1D. CONCLUSIONS Reduction of DOC2B is an early feature of T1D, and DOC2B abundance may serve as a valuable in vivo indicator of β-cell mass and an early biomarker of T1D.
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Affiliation(s)
- Arianne Aslamy
- Department of Molecular and Cellular Endocrinology, Diabetes & Metabolism
Research Institute, and Beckman Research Institute of City of Hope, Duarte, California
- Department of Cellular and Integrative Physiology, Indiana University School of
Medicine, Indianapolis, Indiana
| | - Eunjin Oh
- Department of Molecular and Cellular Endocrinology, Diabetes & Metabolism
Research Institute, and Beckman Research Institute of City of Hope, Duarte, California
| | - Miwon Ahn
- Department of Molecular and Cellular Endocrinology, Diabetes & Metabolism
Research Institute, and Beckman Research Institute of City of Hope, Duarte, California
| | - Abu Saleh Md Moin
- Department of Molecular and Cellular Endocrinology, Diabetes & Metabolism
Research Institute, and Beckman Research Institute of City of Hope, Duarte, California
| | - Mariann Chang
- Department of Molecular and Cellular Endocrinology, Diabetes & Metabolism
Research Institute, and Beckman Research Institute of City of Hope, Duarte, California
| | - Molly Duncan
- Department of Pediatrics, Section of Pediatric Endocrinology/Diabetology, and
Wells Center for Pediatric Research, Indiana University School of Medicine, Indianapolis,
Indiana
| | - Jeannette Hacker-Stratton
- Department of Clinical and Translational Research and Cellular Therapeutics,
Diabetes & Metabolism Research Institute, and Beckman Research Institute of City of
Hope, Duarte, California
| | - Mohamed El-Shahawy
- Department of Clinical and Translational Research and Cellular Therapeutics,
Diabetes & Metabolism Research Institute, and Beckman Research Institute of City of
Hope, Duarte, California
| | - Fouad Kandeel
- Department of Clinical and Translational Research and Cellular Therapeutics,
Diabetes & Metabolism Research Institute, and Beckman Research Institute of City of
Hope, Duarte, California
| | - Linda A DiMeglio
- Department of Pediatrics, Section of Pediatric Endocrinology/Diabetology, and
Wells Center for Pediatric Research, Indiana University School of Medicine, Indianapolis,
Indiana
| | - Debbie C Thurmond
- Department of Molecular and Cellular Endocrinology, Diabetes & Metabolism
Research Institute, and Beckman Research Institute of City of Hope, Duarte, California
- Department of Cellular and Integrative Physiology, Indiana University School of
Medicine, Indianapolis, Indiana
- Correspondence and Reprint Requests: Debbie C. Thurmond, PhD, Department of Molecular and Cellular Endocrinology,
Diabetes and Metabolism Research Institute, and Beckman Research Institute of City of
Hope, 1500 East Duarte Road, Duarte, California 91010. E-mail:
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15
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Fazakerley DJ, Minard AY, Krycer JR, Thomas KC, Stöckli J, Harney DJ, Burchfield JG, Maghzal GJ, Caldwell ST, Hartley RC, Stocker R, Murphy MP, James DE. Mitochondrial oxidative stress causes insulin resistance without disrupting oxidative phosphorylation. J Biol Chem 2018; 293:7315-7328. [PMID: 29599292 PMCID: PMC5950018 DOI: 10.1074/jbc.ra117.001254] [Citation(s) in RCA: 96] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2017] [Revised: 03/19/2018] [Indexed: 01/02/2023] Open
Abstract
Mitochondrial oxidative stress, mitochondrial dysfunction, or both have been implicated in insulin resistance. However, disentangling the individual roles of these processes in insulin resistance has been difficult because they often occur in tandem, and tools that selectively increase oxidant production without impairing mitochondrial respiration have been lacking. Using the dimer/monomer status of peroxiredoxin isoforms as an indicator of compartmental hydrogen peroxide burden, we provide evidence that oxidative stress is localized to mitochondria in insulin-resistant 3T3-L1 adipocytes and adipose tissue from mice. To dissociate oxidative stress from impaired oxidative phosphorylation and study whether mitochondrial oxidative stress per se can cause insulin resistance, we used mitochondria-targeted paraquat (MitoPQ) to generate superoxide within mitochondria without directly disrupting the respiratory chain. At ≤10 μm, MitoPQ specifically increased mitochondrial superoxide and hydrogen peroxide without altering mitochondrial respiration in intact cells. Under these conditions, MitoPQ impaired insulin-stimulated glucose uptake and glucose transporter 4 (GLUT4) translocation to the plasma membrane in both adipocytes and myotubes. MitoPQ recapitulated many features of insulin resistance found in other experimental models, including increased oxidants in mitochondria but not cytosol; a more profound effect on glucose transport than on other insulin-regulated processes, such as protein synthesis and lipolysis; an absence of overt defects in insulin signaling; and defective insulin- but not AMP-activated protein kinase (AMPK)-regulated GLUT4 translocation. We conclude that elevated mitochondrial oxidants rapidly impair insulin-regulated GLUT4 translocation and significantly contribute to insulin resistance and that MitoPQ is an ideal tool for studying the link between mitochondrial oxidative stress and regulated GLUT4 trafficking.
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Affiliation(s)
- Daniel J Fazakerley
- Charles Perkins Centre, School of Life and Environmental Sciences, Camperdown, New South Wales 2006, Australia
| | - Annabel Y Minard
- Charles Perkins Centre, School of Life and Environmental Sciences, Camperdown, New South Wales 2006, Australia
| | - James R Krycer
- Charles Perkins Centre, School of Life and Environmental Sciences, Camperdown, New South Wales 2006, Australia
| | - Kristen C Thomas
- Charles Perkins Centre, School of Life and Environmental Sciences, Camperdown, New South Wales 2006, Australia
| | - Jacqueline Stöckli
- Charles Perkins Centre, School of Life and Environmental Sciences, Camperdown, New South Wales 2006, Australia
| | - Dylan J Harney
- Charles Perkins Centre, School of Life and Environmental Sciences, Camperdown, New South Wales 2006, Australia
| | - James G Burchfield
- Charles Perkins Centre, School of Life and Environmental Sciences, Camperdown, New South Wales 2006, Australia
| | - Ghassan J Maghzal
- Vascular Biology Division, Victor Chang Cardiac Research Institute, Darlinghurst, New South Wales 2010, Australia; St. Vincent's Clinical School, University of New South Wales, Sydney, New South Wales 2052, Australia
| | - Stuart T Caldwell
- School of Chemistry, University of Glasgow, Glasgow G12 8QQ, United Kingdom
| | - Richard C Hartley
- School of Chemistry, University of Glasgow, Glasgow G12 8QQ, United Kingdom
| | - Roland Stocker
- Vascular Biology Division, Victor Chang Cardiac Research Institute, Darlinghurst, New South Wales 2010, Australia; St. Vincent's Clinical School, University of New South Wales, Sydney, New South Wales 2052, Australia
| | - Michael P Murphy
- MRC Mitochondrial Biology Unit, Hills Road, University of Cambridge, Cambridge CB2 0XY, United Kingdom
| | - David E James
- Charles Perkins Centre, School of Life and Environmental Sciences, Camperdown, New South Wales 2006, Australia; Charles Perkins Centre, Sydney Medical School, University of Sydney, Camperdown, New South Wales 2006, Australia.
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16
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Burchfield JG, Kebede MA, Meoli CC, Stöckli J, Whitworth PT, Wright AL, Hoffman NJ, Minard AY, Ma X, Krycer JR, Nelson ME, Tan SX, Yau B, Thomas KC, Wee NKY, Khor EC, Enriquez RF, Vissel B, Biden TJ, Baldock PA, Hoehn KL, Cantley J, Cooney GJ, James DE, Fazakerley DJ. High dietary fat and sucrose results in an extensive and time-dependent deterioration in health of multiple physiological systems in mice. J Biol Chem 2018; 293:5731-5745. [PMID: 29440390 DOI: 10.1074/jbc.ra117.000808] [Citation(s) in RCA: 52] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2017] [Revised: 02/12/2018] [Indexed: 01/17/2023] Open
Abstract
Obesity is associated with metabolic dysfunction, including insulin resistance and hyperinsulinemia, and with disorders such as cardiovascular disease, osteoporosis, and neurodegeneration. Typically, these pathologies are examined in discrete model systems and with limited temporal resolution, and whether these disorders co-occur is therefore unclear. To address this question, here we examined multiple physiological systems in male C57BL/6J mice following prolonged exposure to a high-fat/high-sucrose diet (HFHSD). HFHSD-fed mice rapidly exhibited metabolic alterations, including obesity, hyperleptinemia, physical inactivity, glucose intolerance, peripheral insulin resistance, fasting hyperglycemia, ectopic lipid deposition, and bone deterioration. Prolonged exposure to HFHSD resulted in morbid obesity, ectopic triglyceride deposition in liver and muscle, extensive bone loss, sarcopenia, hyperinsulinemia, and impaired short-term memory. Although many of these defects are typically associated with aging, HFHSD did not alter telomere length in white blood cells, indicating that this diet did not generally promote all aspects of aging. Strikingly, glucose homeostasis was highly dynamic. Glucose intolerance was evident in HFHSD-fed mice after 1 week and was maintained for 24 weeks. Beyond 24 weeks, however, glucose tolerance improved in HFHSD-fed mice, and by 60 weeks, it was indistinguishable from that of chow-fed mice. This improvement coincided with adaptive β-cell hyperplasia and hyperinsulinemia, without changes in insulin sensitivity in muscle or adipose tissue. Assessment of insulin secretion in isolated islets revealed that leptin, which inhibited insulin secretion in the chow-fed mice, potentiated glucose-stimulated insulin secretion in the HFHSD-fed mice after 60 weeks. Overall, the excessive calorie intake was accompanied by deteriorating function of numerous physiological systems.
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Affiliation(s)
- James G Burchfield
- From the Charles Perkins Centre, School of Life and Environmental Sciences, University of Sydney, Camperdown, New South Wales 2006, Australia.,Garvan Institute of Medical Research, Darlinghurst, Sydney, New South Wales 2010, Australia, and
| | - Melkam A Kebede
- From the Charles Perkins Centre, School of Life and Environmental Sciences, University of Sydney, Camperdown, New South Wales 2006, Australia
| | - Christopher C Meoli
- From the Charles Perkins Centre, School of Life and Environmental Sciences, University of Sydney, Camperdown, New South Wales 2006, Australia.,Garvan Institute of Medical Research, Darlinghurst, Sydney, New South Wales 2010, Australia, and
| | - Jacqueline Stöckli
- From the Charles Perkins Centre, School of Life and Environmental Sciences, University of Sydney, Camperdown, New South Wales 2006, Australia.,Garvan Institute of Medical Research, Darlinghurst, Sydney, New South Wales 2010, Australia, and
| | - P Tess Whitworth
- Garvan Institute of Medical Research, Darlinghurst, Sydney, New South Wales 2010, Australia, and
| | - Amanda L Wright
- Garvan Institute of Medical Research, Darlinghurst, Sydney, New South Wales 2010, Australia, and
| | - Nolan J Hoffman
- From the Charles Perkins Centre, School of Life and Environmental Sciences, University of Sydney, Camperdown, New South Wales 2006, Australia.,Garvan Institute of Medical Research, Darlinghurst, Sydney, New South Wales 2010, Australia, and
| | - Annabel Y Minard
- From the Charles Perkins Centre, School of Life and Environmental Sciences, University of Sydney, Camperdown, New South Wales 2006, Australia.,Garvan Institute of Medical Research, Darlinghurst, Sydney, New South Wales 2010, Australia, and
| | - Xiuquan Ma
- Garvan Institute of Medical Research, Darlinghurst, Sydney, New South Wales 2010, Australia, and
| | - James R Krycer
- From the Charles Perkins Centre, School of Life and Environmental Sciences, University of Sydney, Camperdown, New South Wales 2006, Australia.,Garvan Institute of Medical Research, Darlinghurst, Sydney, New South Wales 2010, Australia, and
| | - Marin E Nelson
- From the Charles Perkins Centre, School of Life and Environmental Sciences, University of Sydney, Camperdown, New South Wales 2006, Australia
| | - Shi-Xiong Tan
- Garvan Institute of Medical Research, Darlinghurst, Sydney, New South Wales 2010, Australia, and
| | - Belinda Yau
- From the Charles Perkins Centre, School of Life and Environmental Sciences, University of Sydney, Camperdown, New South Wales 2006, Australia
| | - Kristen C Thomas
- From the Charles Perkins Centre, School of Life and Environmental Sciences, University of Sydney, Camperdown, New South Wales 2006, Australia.,Garvan Institute of Medical Research, Darlinghurst, Sydney, New South Wales 2010, Australia, and
| | - Natalie K Y Wee
- Garvan Institute of Medical Research, Darlinghurst, Sydney, New South Wales 2010, Australia, and
| | - Ee-Cheng Khor
- Garvan Institute of Medical Research, Darlinghurst, Sydney, New South Wales 2010, Australia, and
| | - Ronaldo F Enriquez
- Garvan Institute of Medical Research, Darlinghurst, Sydney, New South Wales 2010, Australia, and
| | - Bryce Vissel
- Garvan Institute of Medical Research, Darlinghurst, Sydney, New South Wales 2010, Australia, and
| | - Trevor J Biden
- Garvan Institute of Medical Research, Darlinghurst, Sydney, New South Wales 2010, Australia, and
| | - Paul A Baldock
- Garvan Institute of Medical Research, Darlinghurst, Sydney, New South Wales 2010, Australia, and
| | - Kyle L Hoehn
- Garvan Institute of Medical Research, Darlinghurst, Sydney, New South Wales 2010, Australia, and
| | - James Cantley
- Garvan Institute of Medical Research, Darlinghurst, Sydney, New South Wales 2010, Australia, and
| | - Gregory J Cooney
- From the Charles Perkins Centre, School of Life and Environmental Sciences, University of Sydney, Camperdown, New South Wales 2006, Australia.,Charles Perkins Centre, Sydney Medical School, University of Sydney, Camperdown, New South Wales 2006, Australia
| | - David E James
- From the Charles Perkins Centre, School of Life and Environmental Sciences, University of Sydney, Camperdown, New South Wales 2006, Australia, .,Garvan Institute of Medical Research, Darlinghurst, Sydney, New South Wales 2010, Australia, and.,Charles Perkins Centre, Sydney Medical School, University of Sydney, Camperdown, New South Wales 2006, Australia
| | - Daniel J Fazakerley
- From the Charles Perkins Centre, School of Life and Environmental Sciences, University of Sydney, Camperdown, New South Wales 2006, Australia.,Garvan Institute of Medical Research, Darlinghurst, Sydney, New South Wales 2010, Australia, and
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17
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Rorsman P, Ashcroft FM. Pancreatic β-Cell Electrical Activity and Insulin Secretion: Of Mice and Men. Physiol Rev 2018; 98:117-214. [PMID: 29212789 PMCID: PMC5866358 DOI: 10.1152/physrev.00008.2017] [Citation(s) in RCA: 443] [Impact Index Per Article: 73.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2017] [Revised: 05/30/2017] [Accepted: 06/18/2017] [Indexed: 12/14/2022] Open
Abstract
The pancreatic β-cell plays a key role in glucose homeostasis by secreting insulin, the only hormone capable of lowering the blood glucose concentration. Impaired insulin secretion results in the chronic hyperglycemia that characterizes type 2 diabetes (T2DM), which currently afflicts >450 million people worldwide. The healthy β-cell acts as a glucose sensor matching its output to the circulating glucose concentration. It does so via metabolically induced changes in electrical activity, which culminate in an increase in the cytoplasmic Ca2+ concentration and initiation of Ca2+-dependent exocytosis of insulin-containing secretory granules. Here, we review recent advances in our understanding of the β-cell transcriptome, electrical activity, and insulin exocytosis. We highlight salient differences between mouse and human β-cells, provide models of how the different ion channels contribute to their electrical activity and insulin secretion, and conclude by discussing how these processes become perturbed in T2DM.
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Affiliation(s)
- Patrik Rorsman
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Churchill Hospital, Oxford, United Kingdom; Department of Neuroscience and Physiology, Metabolic Research Unit, Göteborg, Sweden; and Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
| | - Frances M Ashcroft
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Churchill Hospital, Oxford, United Kingdom; Department of Neuroscience and Physiology, Metabolic Research Unit, Göteborg, Sweden; and Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
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18
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Gaisano HY. Recent new insights into the role of SNARE and associated proteins in insulin granule exocytosis. Diabetes Obes Metab 2017; 19 Suppl 1:115-123. [PMID: 28880475 DOI: 10.1111/dom.13001] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/27/2017] [Revised: 04/23/2017] [Accepted: 05/02/2017] [Indexed: 01/22/2023]
Abstract
Initial work on the exocytotic machinery of predocked insulin secretory granules (SGs) in pancreatic β-cells mimicked the SNARE hypothesis work in neurons, which includes SM/SNARE complex and associated priming proteins, fusion clamps and Ca2+ sensors. However, β-cell SGs, unlike neuronal synaptic vesicles, exhibit a biphasic secretory response that requires additional distinct features in exocytosis including newcomer SGs that undergo minimal docking time at the plasma membrane (PM) before fusion and multi-SG (compound) fusion. These exocytotic events are mediated by Munc18/SNARE complexes distinct from that which mediates predocked SG fusion. We review some recent insights in SNARE complex assembly and the promiscuity in SM/SNARE complex formation, whereby both contribute to conferring different insulin SG fusion kinetics. Some SNARE and associated proteins play non-fusion roles, including tethering SGs to Ca2+ channels, SG recruitment from cell interior to PM, and inhibitory SNAREs that block the action of profusion SNAREs. We discuss new insights into how sub-PM cytoskeletal mesh gates SG access to the PM and the targeting of SG exocytosis to PM domains in functionally polarized β-cells within intact islets. These recent developments have major implications on devising clever SNARE replacement therapies that could restore the deficient insulin secretion in diabetic islet β-cells.
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19
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Jaldin-Fincati JR, Pavarotti M, Frendo-Cumbo S, Bilan PJ, Klip A. Update on GLUT4 Vesicle Traffic: A Cornerstone of Insulin Action. Trends Endocrinol Metab 2017; 28:597-611. [PMID: 28602209 DOI: 10.1016/j.tem.2017.05.002] [Citation(s) in RCA: 180] [Impact Index Per Article: 25.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/20/2017] [Revised: 05/08/2017] [Accepted: 05/09/2017] [Indexed: 12/20/2022]
Abstract
Glucose transport is rate limiting for dietary glucose utilization by muscle and fat. The glucose transporter GLUT4 is dynamically sorted and retained intracellularly and redistributes to the plasma membrane (PM) by insulin-regulated vesicular traffic, or 'GLUT4 translocation'. Here we emphasize recent findings in GLUT4 translocation research. The application of total internal reflection fluorescence microscopy (TIRFM) has increased our understanding of insulin-regulated events beneath the PM, such as vesicle tethering and membrane fusion. We describe recent findings on Akt-targeted Rab GTPase-activating proteins (GAPs) (TBC1D1, TBC1D4, TBC1D13) and downstream Rab GTPases (Rab8a, Rab10, Rab13, Rab14, and their effectors) along with the input of Rac1 and actin filaments, molecular motors [myosinVa (MyoVa), myosin1c (Myo1c), myosinIIA (MyoIIA)], and membrane fusion regulators (syntaxin4, munc18c, Doc2b). Collectively these findings reveal novel events in insulin-regulated GLUT4 traffic.
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Affiliation(s)
| | - Martin Pavarotti
- Cell Biology Program, The Hospital for Sick Children, Toronto, ON M5J 2L4, Canada; IHEM, Universidad Nacional de Cuyo, CONICET, Mendoza 5500, Argentina
| | - Scott Frendo-Cumbo
- Cell Biology Program, The Hospital for Sick Children, Toronto, ON M5J 2L4, Canada; Department of Physiology, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Philip J Bilan
- Cell Biology Program, The Hospital for Sick Children, Toronto, ON M5J 2L4, Canada
| | - Amira Klip
- Cell Biology Program, The Hospital for Sick Children, Toronto, ON M5J 2L4, Canada; Department of Physiology, University of Toronto, Toronto, ON M5S 1A8, Canada; Department of Biochemistry, University of Toronto, Toronto, ON M5S 1A8, Canada.
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20
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Zhang X, Jiang S, Mitok KA, Li L, Attie AD, Martin TFJ. BAIAP3, a C2 domain-containing Munc13 protein, controls the fate of dense-core vesicles in neuroendocrine cells. J Cell Biol 2017. [PMID: 28626000 PMCID: PMC5496627 DOI: 10.1083/jcb.201702099] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Zhang et al. conducted a siRNA screen of C2 domain proteins involved in regulated peptide secretion. One of the hits, a Munc13 family member BAIAP3, was characterized as endosome localized involved in post-exocytic dense-core vesicle protein recycling to the TGN. BAIAP3 knockdown inhibited dense-core vesicle maturation/stability in neuroendocrine/endocrine cells. Dense-core vesicle (DCV) exocytosis is a SNARE (soluble N-ethylmaleimide–sensitive fusion attachment protein receptor)-dependent anterograde trafficking pathway that requires multiple proteins for regulation. Several C2 domain–containing proteins are known to regulate Ca2+-dependent DCV exocytosis in neuroendocrine cells. In this study, we identified others by screening all (∼139) human C2 domain–containing proteins by RNA interference in neuroendocrine cells. 40 genes were identified, including several encoding proteins with known roles (CAPS [calcium-dependent activator protein for secretion 1], Munc13-2, RIM1, and SYT10) and many with unknown roles. One of the latter, BAIAP3, is a secretory cell–specific Munc13-4 paralog of unknown function. BAIAP3 knockdown caused accumulation of fusion-incompetent DCVs in BON neuroendocrine cells and lysosomal degradation (crinophagy) of insulin-containing DCVs in INS-1 β cells. BAIAP3 localized to endosomes was required for Golgi trans-Golgi network 46 (TGN46) recycling, exhibited Ca2+-stimulated interactions with TGN SNAREs, and underwent Ca2+-stimulated TGN recruitment. Thus, unlike other Munc13 proteins, BAIAP3 functions indirectly in DCV exocytosis by affecting DCV maturation through its role in DCV protein recycling. Ca2+ rises that stimulate DCV exocytosis may stimulate BAIAP3-dependent retrograde trafficking to maintain DCV protein homeostasis and DCV function.
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Affiliation(s)
- Xingmin Zhang
- Department of Biochemistry, University of Wisconsin, Madison, WI.,Program in Cellular and Molecular Biology, University of Wisconsin, Madison, WI
| | - Shan Jiang
- School of Pharmacy, University of Wisconsin, Madison, WI
| | - Kelly A Mitok
- Department of Biochemistry, University of Wisconsin, Madison, WI
| | - Lingjun Li
- School of Pharmacy, University of Wisconsin, Madison, WI
| | - Alan D Attie
- Department of Biochemistry, University of Wisconsin, Madison, WI
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21
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Xiong QY, Yu C, Zhang Y, Ling L, Wang L, Gao JL. Key proteins involved in insulin vesicle exocytosis and secretion. Biomed Rep 2017; 6:134-139. [PMID: 28357064 DOI: 10.3892/br.2017.839] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2016] [Accepted: 11/11/2016] [Indexed: 01/18/2023] Open
Abstract
In vivo insulin secretion is predominantly affected by blood glucose concentration, blood concentration of amino acids, gastrointestinal hormones and free nerve functional status, in addition to other factors. Insulin is one of the most important hormones in the body, and its secretion is precisely controlled by nutrients, neurotransmitters and hormones. The insulin exocytosis process is similar to the neurotransmitter release mechanism. There are various types of proteins and lipids that participate in the insulin secretory vesicle fusion process, such as soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) protein, Ras-related proteins and vacuolar-type H+-ATPase (V-ATPase). Notably, the SNARE protein is the molecular basis of exocytotic activity. In the current review, the role of the vesicle membrane proteins (synaptobrevins, vesicle associated membrane proteins and target membrane proteins) and auxiliary proteins (Rab proteins and Munc-18 proteins) in vesicle fusion activity were summarized. A summary of these key proteins involved in insulin granule secretion will facilitate understanding of the pathogenesis of diabetes.
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Affiliation(s)
- Qian-Yin Xiong
- Department of Endocrinology and Genetic Metabolism, Yijishan Hospital of Wannan Medical College, Wuhu, Anhui 241002, P.R. China; Anhui Province Key Laboratory of Biological Macro-molecules Research, Wannan Medical College, Wuhu, Anhui 242001, P.R. China
| | - Cui Yu
- Department of Endocrinology and Genetic Metabolism, Yijishan Hospital of Wannan Medical College, Wuhu, Anhui 241002, P.R. China; Anhui Province Key Laboratory of Biological Macro-molecules Research, Wannan Medical College, Wuhu, Anhui 242001, P.R. China
| | - Yao Zhang
- Anhui Province Key Laboratory of Biological Macro-molecules Research, Wannan Medical College, Wuhu, Anhui 242001, P.R. China; Department of Biochemistry and Molecular Biology, Wannan Medical College, Wuhu, Anhui 241001, P.R. China
| | - Liefeng Ling
- Anhui Province Key Laboratory of Biological Macro-molecules Research, Wannan Medical College, Wuhu, Anhui 242001, P.R. China; Department of Biochemistry and Molecular Biology, Wannan Medical College, Wuhu, Anhui 241001, P.R. China
| | - Lizhuo Wang
- Anhui Province Key Laboratory of Biological Macro-molecules Research, Wannan Medical College, Wuhu, Anhui 242001, P.R. China; Department of Biochemistry and Molecular Biology, Wannan Medical College, Wuhu, Anhui 241001, P.R. China
| | - Jia-Lin Gao
- Department of Endocrinology and Genetic Metabolism, Yijishan Hospital of Wannan Medical College, Wuhu, Anhui 241002, P.R. China; Anhui Province Key Laboratory of Biological Macro-molecules Research, Wannan Medical College, Wuhu, Anhui 242001, P.R. China
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22
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Pinheiro PS, Houy S, Sørensen JB. C2-domain containing calcium sensors in neuroendocrine secretion. J Neurochem 2016; 139:943-958. [DOI: 10.1111/jnc.13865] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2016] [Revised: 09/17/2016] [Accepted: 10/05/2016] [Indexed: 12/11/2022]
Affiliation(s)
- Paulo S. Pinheiro
- Center for Neuroscience and Cell Biology; University of Coimbra; Coimbra Portugal
| | - Sébastien Houy
- Department of Neuroscience and Pharmacology; Faculty of Health and Medical Sciences; University of Copenhagen; Copenhagen Denmark
| | - Jakob B. Sørensen
- Department of Neuroscience and Pharmacology; Faculty of Health and Medical Sciences; University of Copenhagen; Copenhagen Denmark
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23
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Collins SC, Do HW, Hastoy B, Hugill A, Adam J, Chibalina MV, Galvanovskis J, Godazgar M, Lee S, Goldsworthy M, Salehi A, Tarasov AI, Rosengren AH, Cox R, Rorsman P. Increased Expression of the Diabetes Gene SOX4 Reduces Insulin Secretion by Impaired Fusion Pore Expansion. Diabetes 2016; 65:1952-61. [PMID: 26993066 PMCID: PMC4996324 DOI: 10.2337/db15-1489] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/29/2015] [Accepted: 03/08/2016] [Indexed: 12/27/2022]
Abstract
The transcription factor Sox4 has been proposed to underlie the increased type 2 diabetes risk linked to an intronic single nucleotide polymorphism in CDKAL1 In a mouse model expressing a mutant form of Sox4, glucose-induced insulin secretion is reduced by 40% despite normal intracellular Ca(2+) signaling and depolarization-evoked exocytosis. This paradox is explained by a fourfold increase in kiss-and-run exocytosis (as determined by single-granule exocytosis measurements) in which the fusion pore connecting the granule lumen to the exterior expands to a diameter of only 2 nm, which does not allow the exit of insulin. Microarray analysis indicated that this correlated with an increased expression of the exocytosis-regulating protein Stxbp6. In a large collection of human islet preparations (n = 63), STXBP6 expression and glucose-induced insulin secretion correlated positively and negatively with SOX4 expression, respectively. Overexpression of SOX4 in the human insulin-secreting cell EndoC-βH2 interfered with granule emptying and inhibited hormone release, the latter effect reversed by silencing STXBP6 These data suggest that increased SOX4 expression inhibits insulin secretion and increased diabetes risk by the upregulation of STXBP6 and an increase in kiss-and-run exocytosis at the expense of full fusion. We propose that pharmacological interventions promoting fusion pore expansion may be effective in diabetes therapy.
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Affiliation(s)
- Stephan C Collins
- Oxford Centre for Diabetes, Endocrinology & Metabolism, Radcliffe Department of Medicine, Oxford, U.K. Université de Bourgogne Franche-Comté, Burgundy, France
| | - Hyun Woong Do
- Oxford Centre for Diabetes, Endocrinology & Metabolism, Radcliffe Department of Medicine, Oxford, U.K
| | - Benoit Hastoy
- Oxford Centre for Diabetes, Endocrinology & Metabolism, Radcliffe Department of Medicine, Oxford, U.K
| | - Alison Hugill
- Mammalian Genetics Unit, MRC Harwell, Oxfordshire, U.K
| | - Julie Adam
- Oxford Centre for Diabetes, Endocrinology & Metabolism, Radcliffe Department of Medicine, Oxford, U.K
| | - Margarita V Chibalina
- Oxford Centre for Diabetes, Endocrinology & Metabolism, Radcliffe Department of Medicine, Oxford, U.K
| | - Juris Galvanovskis
- Oxford Centre for Diabetes, Endocrinology & Metabolism, Radcliffe Department of Medicine, Oxford, U.K. Henry Wellcome Centre for Gene Function, Department of Physiology, Anatomy, and Genetics, University of Oxford, Oxford, U.K
| | - Mahdieh Godazgar
- Oxford Centre for Diabetes, Endocrinology & Metabolism, Radcliffe Department of Medicine, Oxford, U.K
| | - Sheena Lee
- Henry Wellcome Centre for Gene Function, Department of Physiology, Anatomy, and Genetics, University of Oxford, Oxford, U.K
| | | | - Albert Salehi
- Lund University Diabetes Centre, Department of Clinical Sciences, Skåne University Hospital Malmö, Lund University, Malmö, Sweden Department of Neuroscience and Physiology, University of Göteborg, Göteborg, Sweden
| | - Andrei I Tarasov
- Oxford Centre for Diabetes, Endocrinology & Metabolism, Radcliffe Department of Medicine, Oxford, U.K. Oxford National Institute of Health Research, Biomedical Research Centre, Churchill Hospital, Oxford, U.K
| | - Anders H Rosengren
- Lund University Diabetes Centre, Department of Clinical Sciences, Skåne University Hospital Malmö, Lund University, Malmö, Sweden
| | - Roger Cox
- Mammalian Genetics Unit, MRC Harwell, Oxfordshire, U.K
| | - Patrik Rorsman
- Oxford Centre for Diabetes, Endocrinology & Metabolism, Radcliffe Department of Medicine, Oxford, U.K. Department of Neuroscience and Physiology, University of Göteborg, Göteborg, Sweden Oxford National Institute of Health Research, Biomedical Research Centre, Churchill Hospital, Oxford, U.K
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24
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Stöckli J, Meoli CC, Hoffman NJ, Fazakerley DJ, Pant H, Cleasby ME, Ma X, Kleinert M, Brandon AE, Lopez JA, Cooney GJ, James DE. The RabGAP TBC1D1 plays a central role in exercise-regulated glucose metabolism in skeletal muscle. Diabetes 2015; 64:1914-22. [PMID: 25576050 DOI: 10.2337/db13-1489] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/28/2013] [Accepted: 12/24/2014] [Indexed: 11/13/2022]
Abstract
Insulin and exercise stimulate glucose uptake into skeletal muscle via different pathways. Both stimuli converge on the translocation of the glucose transporter GLUT4 from intracellular vesicles to the cell surface. Two Rab guanosine triphosphatases-activating proteins (GAPs) have been implicated in this process: AS160 for insulin stimulation and its homolog, TBC1D1, are suggested to regulate exercise-mediated glucose uptake into muscle. TBC1D1 has also been implicated in obesity in humans and mice. We investigated the role of TBC1D1 in glucose metabolism by generating TBC1D1(-/-) mice and analyzing body weight, insulin action, and exercise. TBC1D1(-/-) mice showed normal glucose and insulin tolerance, with no difference in body weight compared with wild-type littermates. GLUT4 protein levels were reduced by ∼40% in white TBC1D1(-/-) muscle, and TBC1D1(-/-) mice showed impaired exercise endurance together with impaired exercise-mediated 2-deoxyglucose uptake into white but not red muscles. These findings indicate that the RabGAP TBC1D1 plays a key role in regulating GLUT4 protein levels and in exercise-mediated glucose uptake in nonoxidative muscle fibers.
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Affiliation(s)
- Jacqueline Stöckli
- Charles Perkins Centre, University of Sydney, Sydney, New South Wales, Australia School of Molecular Bioscience, University of Sydney, Sydney, New South Wales, Australia Garvan Institute of Medical Research, Sydney, New South Wales, Australia St Vincent's Clinical School, Faculty of Medicine, University of New South Wales, Sydney, New South Wales, Australia
| | - Christopher C Meoli
- Charles Perkins Centre, University of Sydney, Sydney, New South Wales, Australia School of Molecular Bioscience, University of Sydney, Sydney, New South Wales, Australia Garvan Institute of Medical Research, Sydney, New South Wales, Australia
| | - Nolan J Hoffman
- Charles Perkins Centre, University of Sydney, Sydney, New South Wales, Australia School of Molecular Bioscience, University of Sydney, Sydney, New South Wales, Australia Garvan Institute of Medical Research, Sydney, New South Wales, Australia
| | - Daniel J Fazakerley
- Charles Perkins Centre, University of Sydney, Sydney, New South Wales, Australia School of Molecular Bioscience, University of Sydney, Sydney, New South Wales, Australia Garvan Institute of Medical Research, Sydney, New South Wales, Australia
| | - Himani Pant
- Garvan Institute of Medical Research, Sydney, New South Wales, Australia
| | - Mark E Cleasby
- The Royal Veterinary College, University of London, London, U.K
| | - Xiuquan Ma
- Garvan Institute of Medical Research, Sydney, New South Wales, Australia
| | - Maximilian Kleinert
- Garvan Institute of Medical Research, Sydney, New South Wales, Australia Molecular Physiology Group, Department of Nutrition, Exercise and Sports, August Krogh Centre, University of Copenhagen, Copenhagen, Denmark
| | - Amanda E Brandon
- Garvan Institute of Medical Research, Sydney, New South Wales, Australia
| | - Jamie A Lopez
- Garvan Institute of Medical Research, Sydney, New South Wales, Australia
| | - Gregory J Cooney
- Garvan Institute of Medical Research, Sydney, New South Wales, Australia St Vincent's Clinical School, Faculty of Medicine, University of New South Wales, Sydney, New South Wales, Australia
| | - David E James
- Charles Perkins Centre, University of Sydney, Sydney, New South Wales, Australia School of Molecular Bioscience, University of Sydney, Sydney, New South Wales, Australia Garvan Institute of Medical Research, Sydney, New South Wales, Australia School of Medicine, University of Sydney, Sydney, New South Wales, Australia
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25
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Doc2b serves as a scaffolding platform for concurrent binding of multiple Munc18 isoforms in pancreatic islet β-cells. Biochem J 2015; 464:251-8. [PMID: 25190515 DOI: 10.1042/bj20140845] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Biphasic glucose-stimulated insulin secretion (GSIS) from pancreatic β-cells involves soluble N-ethylmaleimide-sensitive fusion protein-attachment protein receptor (SNARE) protein-regulated exocytosis. SNARE complex assembly further requires the regulatory proteins Munc18c, Munc18-1 and Doc2b. Munc18-1 and Munc18c are required for first- and second-phase GSIS respectively. These distinct Munc18-1 and Munc18c roles are related to their transient high-affinity binding with their cognate target (t-)SNAREs, Syntaxin 1A and Syntaxin 4 respectively. Doc2b is essential for both phases of GSIS, yet the molecular basis for this remains unresolved. Because Doc2b binds to Munc18-1 and Munc18c via its distinct C2A and C2B domains respectively, we hypothesized that Doc2b may provide a plasma membrane-localized scaffold/platform for transient docking of these Munc18 isoforms during GSIS. Towards this, macromolecular complexes composed of Munc18c, Doc2b and Munc18-1 were detected in β-cells. In vitro interaction assays indicated that Doc2b is required to bridge the interaction between Munc18c and Munc18-1 in the macromolecular complex; Munc18c and Munc18-1 failed to associate in the absence of Doc2b. Competition-based GST-Doc2b interaction assays revealed that Doc2b could simultaneously bind both Munc18-1 and Munc18c. Hence these data support a working model wherein Doc2b functions as a docking platform/scaffold for transient interactions with the multiple Munc18 isoforms operative in insulin release, promoting SNARE assembly.
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26
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Roux PF, Boutin M, Désert C, Djari A, Esquerré D, Klopp C, Lagarrigue S, Demeure O. Re-sequencing data for refining candidate genes and polymorphisms in QTL regions affecting adiposity in chicken. PLoS One 2014; 9:e111299. [PMID: 25333370 PMCID: PMC4205046 DOI: 10.1371/journal.pone.0111299] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2014] [Accepted: 09/22/2014] [Indexed: 12/30/2022] Open
Abstract
In this study, we propose an approach aiming at fine-mapping adiposity QTL in chicken, integrating whole genome re-sequencing data. First, two QTL regions for adiposity were identified by performing a classical linkage analysis on 1362 offspring in 11 sire families obtained by crossing two meat-type chicken lines divergently selected for abdominal fat weight. Those regions, located on chromosome 7 and 19, contained a total of 77 and 84 genes, respectively. Then, SNPs and indels in these regions were identified by re-sequencing sires. Considering issues related to polymorphism annotations for regulatory regions, we focused on the 120 and 104 polymorphisms having an impact on protein sequence, and located in coding regions of 35 and 42 genes situated in the two QTL regions. Subsequently, a filter was applied on SNPs considering their potential impact on the protein function based on conservation criteria. For the two regions, we identified 42 and 34 functional polymorphisms carried by 18 and 24 genes, and likely to deeply impact protein, including 3 coding indels and 4 nonsense SNPs. Finally, using gene functional annotation, a short list of 17 and 4 polymorphisms in 6 and 4 functional genes has been defined. Even if we cannot exclude that the causal polymorphisms may be located in regulatory regions, this strategy gives a complete overview of the candidate polymorphisms in coding regions and prioritize them on conservation- and functional-based arguments.
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Affiliation(s)
- Pierre-François Roux
- INRA, UMR1348 PEGASE, Saint-Gilles, France
- Agrocampus Ouest, UMR1348 PEGASE, Rennes, France
- Université Européenne de Bretagne, Rennes, France
| | - Morgane Boutin
- INRA, UMR1348 PEGASE, Saint-Gilles, France
- Agrocampus Ouest, UMR1348 PEGASE, Rennes, France
- Université Européenne de Bretagne, Rennes, France
| | - Colette Désert
- INRA, UMR1348 PEGASE, Saint-Gilles, France
- Agrocampus Ouest, UMR1348 PEGASE, Rennes, France
- Université Européenne de Bretagne, Rennes, France
| | | | - Diane Esquerré
- INRA, UMR1388 GenPhySE, GeT-PlaGe, Castanet-Tolosan, France
| | | | - Sandrine Lagarrigue
- INRA, UMR1348 PEGASE, Saint-Gilles, France
- Agrocampus Ouest, UMR1348 PEGASE, Rennes, France
- Université Européenne de Bretagne, Rennes, France
| | - Olivier Demeure
- INRA, UMR1348 PEGASE, Saint-Gilles, France
- Agrocampus Ouest, UMR1348 PEGASE, Rennes, France
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