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Szodorai E, Hevesi Z, Wagner L, Hökfelt TGM, Harkany T, Schnell R. A hydrophobic groove in secretagogin allows for alternate interactions with SNAP-25 and syntaxin-4 in endocrine tissues. Proc Natl Acad Sci U S A 2024; 121:e2309211121. [PMID: 38593081 PMCID: PMC11032447 DOI: 10.1073/pnas.2309211121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2023] [Accepted: 03/09/2024] [Indexed: 04/11/2024] Open
Abstract
Vesicular release of neurotransmitters and hormones relies on the dynamic assembly of the exocytosis/trans-SNARE complex through sequential interactions of synaptobrevins, syntaxins, and SNAP-25. Despite SNARE-mediated release being fundamental for intercellular communication in all excitable tissues, the role of auxiliary proteins modulating the import of reserve vesicles to the active zone, and thus, scaling repetitive exocytosis remains less explored. Secretagogin is a Ca2+-sensor protein with SNAP-25 being its only known interacting partner. SNAP-25 anchors readily releasable vesicles within the active zone, thus being instrumental for 1st phase release. However, genetic deletion of secretagogin impedes 2nd phase release instead, calling for the existence of alternative protein-protein interactions. Here, we screened the secretagogin interactome in the brain and pancreas, and found syntaxin-4 grossly overrepresented. Ca2+-loaded secretagogin interacted with syntaxin-4 at nanomolar affinity and 1:1 stoichiometry. Crystal structures of the protein complexes revealed a hydrophobic groove in secretagogin for the binding of syntaxin-4. This groove was also used to bind SNAP-25. In mixtures of equimolar recombinant proteins, SNAP-25 was sequestered by secretagogin in competition with syntaxin-4. Kd differences suggested that secretagogin could shape unidirectional vesicle movement by sequential interactions, a hypothesis supported by in vitro biological data. This mechanism could facilitate the movement of transport vesicles toward release sites, particularly in the endocrine pancreas where secretagogin, SNAP-25, and syntaxin-4 coexist in both α- and β-cells. Thus, secretagogin could modulate the pace and fidelity of vesicular hormone release by differential protein interactions.
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Affiliation(s)
- Edit Szodorai
- Division of Molecular and Cellular Neuroendocrinology, Department of Neuroscience, Biomedicum 7D, Karolinska Institutet, SolnaSE-17165, Sweden
- Department of Molecular Neurosciences, Center for Brain Research, Medical University of Vienna, ViennaA-1090, Austria
| | - Zsofia Hevesi
- Department of Molecular Neurosciences, Center for Brain Research, Medical University of Vienna, ViennaA-1090, Austria
| | - Ludwig Wagner
- Department of Internal Medicine III, Medical University of Vienna, ViennaA-1090, Austria
| | - Tomas G. M. Hökfelt
- Division of Molecular and Cellular Neuroendocrinology, Department of Neuroscience, Biomedicum 7D, Karolinska Institutet, SolnaSE-17165, Sweden
| | - Tibor Harkany
- Division of Molecular and Cellular Neuroendocrinology, Department of Neuroscience, Biomedicum 7D, Karolinska Institutet, SolnaSE-17165, Sweden
- Department of Molecular Neurosciences, Center for Brain Research, Medical University of Vienna, ViennaA-1090, Austria
| | - Robert Schnell
- Division of Molecular and Cellular Neuroendocrinology, Department of Neuroscience, Biomedicum 7D, Karolinska Institutet, SolnaSE-17165, Sweden
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Møller AL, Vasan RS, Levy D, Andersson C, Lin H. Integrated omics analysis of coronary artery calcifications and myocardial infarction: the Framingham Heart Study. Sci Rep 2023; 13:21581. [PMID: 38062110 PMCID: PMC10703905 DOI: 10.1038/s41598-023-48848-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2023] [Accepted: 11/30/2023] [Indexed: 12/18/2023] Open
Abstract
Gene function can be described using various measures. We integrated association studies of three types of omics data to provide insights into the pathophysiology of subclinical coronary disease and myocardial infarction (MI). Using multivariable regression models, we associated: (1) single nucleotide polymorphism, (2) DNA methylation, and (3) gene expression with coronary artery calcification (CAC) scores and MI. Among 3106 participants of the Framingham Heart Study, 65 (2.1%) had prevalent MI and 60 (1.9%) had incident MI, median CAC value was 67.8 [IQR 10.8, 274.9], and 1403 (45.2%) had CAC scores > 0 (prevalent CAC). Prevalent CAC was associated with AHRR (linked to smoking) and EXOC3 (affecting platelet function and promoting hemostasis). CAC score was associated with VWA1 (extracellular matrix protein associated with cartilage structure in endomysium). For prevalent MI we identified FYTTD1 (down-regulated in familial hypercholesterolemia) and PINK1 (linked to cardiac tissue homeostasis and ischemia-reperfusion injury). Incident MI was associated with IRX3 (enhancing browning of white adipose tissue) and STXBP3 (controlling trafficking of glucose transporter type 4 to plasma). Using an integrative trans-omics approach, we identified both putatively novel and known candidate genes associated with CAC and MI. Replication of findings is warranted.
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Affiliation(s)
- Amalie Lykkemark Møller
- Section of Preventive Medicine and Epidemiology, Department of Medicine, Boston University School of Medicine, Boston, MA, USA.
- Department of Cardiology, Nordsjællands Hospital, Hillerød, Denmark.
| | - Ramachandran S Vasan
- Section of Preventive Medicine and Epidemiology, Department of Medicine, Boston University School of Medicine, Boston, MA, USA
- Boston University's and National Heart, Lung, and Blood Institute's Framingham Heart Study, Framingham, MA, USA
- University of Texas School of Public Health San Antonio, and Departments of Medicine and Population Health Sciences, University of Texas Health Science Center, San Antonio, TX, USA
| | - Daniel Levy
- Boston University's and National Heart, Lung, and Blood Institute's Framingham Heart Study, Framingham, MA, USA
- Population Sciences Branch, Division of Intramural Research, National Institutes of Health, Bethesda, MD, USA
| | - Charlotte Andersson
- Section of Cardiovascular Medicine, Department of Medicine, Boston Medical Center, Boston University School of Medicine, Boston, MA, USA
| | - Honghuang Lin
- Department of Medicine, University of Massachusetts Chan Medical School, Worcester, MA, USA
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3
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Vinci M, Costanza C, Galati Rando R, Treccarichi S, Saccone S, Carotenuto M, Roccella M, Calì F, Elia M, Vetri L. STXBP6 Gene Mutation: A New Form of SNAREopathy Leads to Developmental Epileptic Encephalopathy. Int J Mol Sci 2023; 24:16436. [PMID: 38003627 PMCID: PMC10670990 DOI: 10.3390/ijms242216436] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2023] [Revised: 11/13/2023] [Accepted: 11/15/2023] [Indexed: 11/26/2023] Open
Abstract
Syntaxin-binding protein 6 (STXBP6), also known as amysin, is an essential component of the SNAP receptor (SNARE) complex and plays a crucial role in neuronal vesicle trafficking. Mutations in genes encoding SNARE proteins are often associated with a broad spectrum of neurological conditions defined as "SNAREopathies", including epilepsy, intellectual disability, and neurodevelopmental disorders such as autism spectrum disorders. The present whole exome sequencing (WES) study describes, for the first time, the occurrence of developmental epileptic encephalopathy and autism spectrum disorders as a result of a de novo deletion within the STXBP6 gene. The truncated protein in the STXBP6 gene leading to a premature stop codon could negatively modulate the synaptic vesicles' exocytosis. Our research aimed to elucidate a plausible, robust correlation between STXBP6 gene deletion and the manifestation of developmental epileptic encephalopathy.
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Affiliation(s)
- Mirella Vinci
- Oasi Research Institute-IRCCS, 94018 Troina, Italy; (M.V.); (R.G.R.); (S.T.); (M.E.); (L.V.)
| | - Carola Costanza
- Department of Psychology, Educational Science and Human Movement, University of Palermo, 90141 Palermo, Italy; (C.C.); (M.R.)
| | - Rosanna Galati Rando
- Oasi Research Institute-IRCCS, 94018 Troina, Italy; (M.V.); (R.G.R.); (S.T.); (M.E.); (L.V.)
| | - Simone Treccarichi
- Oasi Research Institute-IRCCS, 94018 Troina, Italy; (M.V.); (R.G.R.); (S.T.); (M.E.); (L.V.)
| | - Salvatore Saccone
- Department Biological, Geological and Environmental Sciences, University of Catania, Via Androne 81, 95124 Catania, Italy;
| | - Marco Carotenuto
- Clinic of Child and Adolescent Neuropsychiatry, Department of Mental Health, Physical and Preventive Medicine, University of Campania “Luigi Vanvitelli”, 80131 Naples, Italy;
| | - Michele Roccella
- Department of Psychology, Educational Science and Human Movement, University of Palermo, 90141 Palermo, Italy; (C.C.); (M.R.)
| | - Francesco Calì
- Oasi Research Institute-IRCCS, 94018 Troina, Italy; (M.V.); (R.G.R.); (S.T.); (M.E.); (L.V.)
| | - Maurizio Elia
- Oasi Research Institute-IRCCS, 94018 Troina, Italy; (M.V.); (R.G.R.); (S.T.); (M.E.); (L.V.)
| | - Luigi Vetri
- Oasi Research Institute-IRCCS, 94018 Troina, Italy; (M.V.); (R.G.R.); (S.T.); (M.E.); (L.V.)
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4
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Ceddia RP, Zurawski Z, Thompson Gray A, Adegboye F, McDonald-Boyer A, Shi F, Liu D, Maldonado J, Feng J, Li Y, Alford S, Ayala JE, McGuinness OP, Collins S, Hamm HE. Gβγ-SNAP25 exocytotic brake removal enhances insulin action, promotes adipocyte browning, and protects against diet-induced obesity. J Clin Invest 2023; 133:e160617. [PMID: 37561580 PMCID: PMC10541194 DOI: 10.1172/jci160617] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2022] [Accepted: 08/08/2023] [Indexed: 08/12/2023] Open
Abstract
Negative regulation of exocytosis from secretory cells is accomplished through inhibitory signals from Gi/o GPCRs by Gβγ subunit inhibition of 2 mechanisms: decreased calcium entry and direct interaction of Gβγ with soluble N-ethylmaleimide-sensitive factor attachment protein (SNAP) receptor (SNARE) plasma membrane fusion machinery. Previously, we disabled the second mechanism with a SNAP25 truncation (SNAP25Δ3) that decreased Gβγ affinity for the SNARE complex, leaving exocytotic fusion and modulation of calcium entry intact and removing GPCR-Gβγ inhibition of SNARE-mediated exocytosis. Here, we report substantial metabolic benefit in mice carrying this mutation. Snap25Δ3/Δ3 mice exhibited enhanced insulin sensitivity and beiging of white fat. Metabolic protection was amplified in Snap25Δ3/Δ3 mice challenged with a high-fat diet. Glucose homeostasis, whole-body insulin action, and insulin-mediated glucose uptake into white adipose tissue were improved along with resistance to diet-induced obesity. Metabolic protection in Snap25Δ3/Δ3 mice occurred without compromising the physiological response to fasting or cold. All metabolic phenotypes were reversed at thermoneutrality, suggesting that basal autonomic activity was required. Direct electrode stimulation of sympathetic neuron exocytosis from Snap25Δ3/Δ3 inguinal adipose depots resulted in enhanced and prolonged norepinephrine release. Thus, the Gβγ-SNARE interaction represents a cellular mechanism that deserves further exploration as an additional avenue for combating metabolic disease.
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Affiliation(s)
- Ryan P. Ceddia
- Department of Medicine, Division of Cardiovascular Medicine, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Zack Zurawski
- Department of Pharmacology, Vanderbilt University, Nashville, Tennessee, USA
- Department of Anatomy and Cell Biology, University of Illinois at Chicago, Chicago, Illinois, USA
| | | | - Feyisayo Adegboye
- Department of Pharmacology, Vanderbilt University, Nashville, Tennessee, USA
| | | | - Fubiao Shi
- Department of Medicine, Division of Cardiovascular Medicine, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Dianxin Liu
- Department of Medicine, Division of Cardiovascular Medicine, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Jose Maldonado
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, Tennessee, USA
| | - Jiesi Feng
- State Key Laboratory of Membrane Biology, Peking University School of Life Sciences, Beijing, China
- PKU-IDG/McGovern Institute for Brain Research, Beijing, China
- Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China
| | - Yulong Li
- State Key Laboratory of Membrane Biology, Peking University School of Life Sciences, Beijing, China
- PKU-IDG/McGovern Institute for Brain Research, Beijing, China
- Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China
- Chinese Institute for Brain Research, Beijing, China
| | - Simon Alford
- Department of Anatomy and Cell Biology, University of Illinois at Chicago, Chicago, Illinois, USA
| | - Julio E. Ayala
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, Tennessee, USA
| | - Owen P. McGuinness
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, Tennessee, USA
| | - Sheila Collins
- Department of Medicine, Division of Cardiovascular Medicine, Vanderbilt University Medical Center, Nashville, Tennessee, USA
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, Tennessee, USA
| | - Heidi E. Hamm
- Department of Pharmacology, Vanderbilt University, Nashville, Tennessee, USA
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Rahman MM, Pathak A, Schueler KL, Alsharif H, Michl A, Alexander J, Kim JA, Bhatnagar S. Genetic ablation of synaptotagmin-9 alters tomosyn-1 function to increase insulin secretion from pancreatic β-cells improving glucose clearance. FASEB J 2023; 37:e23075. [PMID: 37432648 PMCID: PMC10348599 DOI: 10.1096/fj.202300291rr] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2023] [Revised: 06/19/2023] [Accepted: 06/22/2023] [Indexed: 07/12/2023]
Abstract
Stimulus-coupled insulin secretion from the pancreatic islet β-cells involves the fusion of insulin granules to the plasma membrane (PM) via SNARE complex formation-a cellular process key for maintaining whole-body glucose homeostasis. Less is known about the role of endogenous inhibitors of SNARE complexes in insulin secretion. We show that an insulin granule protein synaptotagmin-9 (Syt9) deletion in mice increased glucose clearance and plasma insulin levels without affecting insulin action compared to the control mice. Upon glucose stimulation, increased biphasic and static insulin secretion were observed from ex vivo islets due to Syt9 loss. Syt9 colocalizes and binds with tomosyn-1 and the PM syntaxin-1A (Stx1A); Stx1A is required for forming SNARE complexes. Syt9 knockdown reduced tomosyn-1 protein abundance via proteasomal degradation and binding of tomosyn-1 to Stx1A. Furthermore, Stx1A-SNARE complex formation was increased, implicating Syt9-tomosyn-1-Stx1A complex is inhibitory in insulin secretion. Rescuing tomosyn-1 blocked the Syt9-knockdown-mediated increases in insulin secretion. This shows that the inhibitory effects of Syt9 on insulin secretion are mediated by tomosyn-1. We report a molecular mechanism by which β-cells modulate their secretory capacity rendering insulin granules nonfusogenic by forming the Syt9-tomosyn-1-Stx1A complex. Altogether, Syt9 loss in β-cells decreases tomosyn-1 protein abundance, increasing the formation of Stx1A-SNARE complexes, insulin secretion, and glucose clearance. These outcomes differ from the previously published work that identified Syt9 has either a positive or no effect of Syt9 on insulin secretion. Future work using β-cell-specific deletion of Syt9 mice is key for establishing the role of Syt9 in insulin secretion.
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Affiliation(s)
- Md Mostafizur Rahman
- Heersink School of Medicine, Division of Endocrinology, Diabetes, & Metabolism, Comprehensive Diabetes Center, University of Alabama, Birmingham, AL, 35294
| | - Asmita Pathak
- Heersink School of Medicine, Division of Endocrinology, Diabetes, & Metabolism, Comprehensive Diabetes Center, University of Alabama, Birmingham, AL, 35294
| | | | - Haifa Alsharif
- Heersink School of Medicine, Division of Endocrinology, Diabetes, & Metabolism, Comprehensive Diabetes Center, University of Alabama, Birmingham, AL, 35294
| | - Ava Michl
- Heersink School of Medicine, Division of Endocrinology, Diabetes, & Metabolism, Comprehensive Diabetes Center, University of Alabama, Birmingham, AL, 35294
| | - Justin Alexander
- Heersink School of Medicine, Division of Endocrinology, Diabetes, & Metabolism, Comprehensive Diabetes Center, University of Alabama, Birmingham, AL, 35294
| | - Jeong-A Kim
- Heersink School of Medicine, Division of Endocrinology, Diabetes, & Metabolism, Comprehensive Diabetes Center, University of Alabama, Birmingham, AL, 35294
| | - Sushant Bhatnagar
- Heersink School of Medicine, Division of Endocrinology, Diabetes, & Metabolism, Comprehensive Diabetes Center, University of Alabama, Birmingham, AL, 35294
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6
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Ramanadham S, Turk J, Bhatnagar S. Noncanonical Regulation of cAMP-Dependent Insulin Secretion and Its Implications in Type 2 Diabetes. Compr Physiol 2023; 13:5023-5049. [PMID: 37358504 PMCID: PMC10809800 DOI: 10.1002/cphy.c220031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/27/2023]
Abstract
Impaired glucose tolerance (IGT) and β-cell dysfunction in insulin resistance associated with obesity lead to type 2 diabetes (T2D). Glucose-stimulated insulin secretion (GSIS) from β-cells occurs via a canonical pathway that involves glucose metabolism, ATP generation, inactivation of K ATP channels, plasma membrane depolarization, and increases in cytosolic concentrations of [Ca 2+ ] c . However, optimal insulin secretion requires amplification of GSIS by increases in cyclic adenosine monophosphate (cAMP) signaling. The cAMP effectors protein kinase A (PKA) and exchange factor activated by cyclic-AMP (Epac) regulate membrane depolarization, gene expression, and trafficking and fusion of insulin granules to the plasma membrane for amplifying GSIS. The widely recognized lipid signaling generated within β-cells by the β-isoform of Ca 2+ -independent phospholipase A 2 enzyme (iPLA 2 β) participates in cAMP-stimulated insulin secretion (cSIS). Recent work has identified the role of a G-protein coupled receptor (GPCR) activated signaling by the complement 1q like-3 (C1ql3) secreted protein in inhibiting cSIS. In the IGT state, cSIS is attenuated, and the β-cell function is reduced. Interestingly, while β-cell-specific deletion of iPLA 2 β reduces cAMP-mediated amplification of GSIS, the loss of iPLA 2 β in macrophages (MØ) confers protection against the development of glucose intolerance associated with diet-induced obesity (DIO). In this article, we discuss canonical (glucose and cAMP) and novel noncanonical (iPLA 2 β and C1ql3) pathways and how they may affect β-cell (dys)function in the context of impaired glucose intolerance associated with obesity and T2D. In conclusion, we provide a perspective that in IGT states, targeting noncanonical pathways along with canonical pathways could be a more comprehensive approach for restoring β-cell function in T2D. © 2023 American Physiological Society. Compr Physiol 13:5023-5049, 2023.
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Affiliation(s)
- Sasanka Ramanadham
- Department of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, Alabama, USA
- Comprehensive Diabetes Center, University of Alabama at Birmingham, Alabama, USA
| | - John Turk
- Department of Medicine, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Sushant Bhatnagar
- Comprehensive Diabetes Center, University of Alabama at Birmingham, Alabama, USA
- Department of Medicine, University of Alabama at Birmingham, Alabama, USA
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7
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Wen L, Yang X, Wu Z, Fu S, Zhan Y, Chen Z, Bi D, Shen Y. The complement inhibitor CD59 is required for GABAergic synaptic transmission in the dentate gyrus. Cell Rep 2023; 42:112349. [PMID: 37027303 DOI: 10.1016/j.celrep.2023.112349] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2022] [Revised: 01/31/2023] [Accepted: 03/21/2023] [Indexed: 04/08/2023] Open
Abstract
Complement-dependent microglia pruning of excitatory synapses has been widely reported in physiological and pathological conditions, with few reports concerning pruning of inhibitory synapses or direct regulation of synaptic transmission by complement components. Here, we report that loss of CD59, an important endogenous inhibitor of the complement system, leads to compromised spatial memory performance. Furthermore, CD59 deficiency impairs GABAergic synaptic transmission in the hippocampal dentate gyrus (DG). This depends on regulation of GABA release triggered by Ca2+ influx through voltage-gated calcium channels (VGCCs) rather than inhibitory synaptic pruning by microglia. Notably, CD59 colocalizes with inhibitory pre-synaptic terminals and regulates SNARE complex assembly. Together, these results demonstrate that the complement regulator CD59 plays an important role in normal hippocampal function.
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Affiliation(s)
- Lang Wen
- Department of Neurology and Institute on Aging and Brain Disorders, The First Affiliated Hospital of USTC, Neurodegenerative Disease Research Center, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei 230026, China
| | - Xiaoli Yang
- Department of Neurology and Institute on Aging and Brain Disorders, The First Affiliated Hospital of USTC, Neurodegenerative Disease Research Center, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei 230026, China
| | - Zujun Wu
- Department of Neurology and Institute on Aging and Brain Disorders, The First Affiliated Hospital of USTC, Neurodegenerative Disease Research Center, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei 230026, China
| | - Shumei Fu
- Department of Neurology and Institute on Aging and Brain Disorders, The First Affiliated Hospital of USTC, Neurodegenerative Disease Research Center, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei 230026, China
| | - Yaxi Zhan
- Department of Neurology and Institute on Aging and Brain Disorders, The First Affiliated Hospital of USTC, Neurodegenerative Disease Research Center, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei 230026, China
| | - Zuolong Chen
- Department of Neurology and Institute on Aging and Brain Disorders, The First Affiliated Hospital of USTC, Neurodegenerative Disease Research Center, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei 230026, China; Suzhou Institute for Advanced Research, University of Science and Technology of China, Suzhou 215000, China
| | - Danlei Bi
- Department of Neurology and Institute on Aging and Brain Disorders, The First Affiliated Hospital of USTC, Neurodegenerative Disease Research Center, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei 230026, China; Anhui Province Key Laboratory of Biomedical Aging Research, University of Science and Technology of China, Hefei 230026, China; Institute of Artificial Intelligence, Hefei Comprehensive National Science Center, Hefei 230026, China; CAS Key Laboratory of Brain Function and Disease, School of Life Sciences, University of Science and Technology of China, Hefei 230026, China; Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai 200031, China.
| | - Yong Shen
- Department of Neurology and Institute on Aging and Brain Disorders, The First Affiliated Hospital of USTC, Neurodegenerative Disease Research Center, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei 230026, China; Anhui Province Key Laboratory of Biomedical Aging Research, University of Science and Technology of China, Hefei 230026, China; CAS Key Laboratory of Brain Function and Disease, School of Life Sciences, University of Science and Technology of China, Hefei 230026, China; Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai 200031, China.
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8
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Oriakhi K, Ibeji CU, Essien EE, Eluehike N, Orumwensodia K, Uadia P, Choudhary IM. In vitro and computational studies on the antiglycation activity of compounds isolated from antidiabetic Tetracera alnifolia stem bark. J Biomol Struct Dyn 2022; 40:9742-9751. [PMID: 34096463 DOI: 10.1080/07391102.2021.1934542] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The continuous search for new compounds in natural-based plants is a promising strategy for the prevention of diseases. This work examined antiglycation activity compounds isolated from the antidiabetic extract of T. alnifolia stem bark via in vitro and computational [molecular dynamics (MD)] approach. Phytochemical investigation of ethyl acetate fraction and the application of spectroscopic methods led to the isolation and elucidation of 3 compounds: quercetin (1), kaempferol (2), and gallic acid (3). Compounds 1, 2 and 3 were then screened for antioxidant and antiglycation activities. Results show that the ethanol extract of T. alnifolia demonstrated good antioxidant activity compared to the standard gallic acid. There was a significant reduction in fasting blood glucose level progressively in diabetic rats, for 21 days compared to diabetic control. Consequently, the antiglycation activity of ethyl acetate fraction had the highest antiglycation activities, followed by dichloromethane (DCM) fraction. Compounds isolated from ethyl acetate fraction, exhibited the highest antiglycation effect for kaempferol followed by quercetin, while gallic acid had the least antiglycation effect. The root mean square of deviation (RMSD) and MM/GBSA energies obtained from molecular dynamics agree with the in vitro antiglycation activity with the sequence of structural stability in the order; kaempferol > quercetin > gallic acid. Therefore, findings from these results suggest that compounds isolated from T. alnifolia possess antiglycation activity.Communicated by Ramaswamy H. Sarma.
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Affiliation(s)
- Kelly Oriakhi
- Department of Medical Biochemistry, University of Benin, Benin, Nigeria
| | - Collins U Ibeji
- Department of Pure and Industrial Chemistry, Faculty of Physical Sciences, University of Nigeria, Nsukka, Enugu State, Nigeria.,Catalysis and Peptide Research Unit, School of Health Sciences, University of KwaZulu-Natal, Durban, South Africa
| | | | - Nkeiruka Eluehike
- Department of Medical Biochemistry, University of Benin, Benin, Nigeria
| | | | - Patrick Uadia
- Department of Biochemistry, University of Benin, Benin, Nigeria
| | - Iqbal M Choudhary
- International Center for Chemical and Biological Sciences, University of Karachi, Karachi, Pakistan
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9
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Liu F, He R, Zhu M, Zhou L, Liu Y, Yu H. Assembly-promoting protein Munc18c stimulates SNARE-dependent membrane fusion through its SNARE-like peptide. J Biol Chem 2022; 298:102470. [PMID: 36087838 PMCID: PMC9547204 DOI: 10.1016/j.jbc.2022.102470] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2022] [Revised: 09/02/2022] [Accepted: 09/03/2022] [Indexed: 11/19/2022] Open
Abstract
Intracellular vesicle fusion requires the soluble N-ethylmaleimide-sensitive factor attachment protein receptors (SNAREs) and their cognate Sec1/Munc18 (SM) proteins. How SM proteins act in concert with trans-SNARE complexes to promote membrane fusion remains incompletely understood. Munc18c, a broadly distributed SM protein, selectively regulates multiple exocytotic pathways, including GLUT4 exocytosis. Here, using an in vitro reconstituted system, we discovered a SNARE-like peptide (SLP), conserved in Munc18-1 of synaptic exocytosis, is crucial to the stimulatory activity of Munc18c in vesicle fusion. The direct stimulation of the SNARE-mediated fusion reaction by SLP further supported the essential role of this fragment. Interestingly, we found SLP strongly accelerates the membrane fusion rate when anchored to the target membrane but not the vesicle membrane, suggesting it primarily interacts with t-SNAREs in cis to drive fusion. Furthermore, we determined the SLP fragment is competitive with the full-length Munc18c protein and specific to the cognate v-SNARE isoforms, supporting how it could resemble Munc18c’s activity in membrane fusion. Together, our findings demonstrate that Munc18c facilitates SNARE-dependent membrane fusion through SLP, revealing that the t-SNARE-SLP binding mode might be a conserved mechanism for the stimulatory function of SM proteins in vesicle fusion.
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Affiliation(s)
- Furong Liu
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Sciences, Nanjing Normal University, Nanjing, China
| | - Ruyue He
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Sciences, Nanjing Normal University, Nanjing, China
| | - Min Zhu
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Sciences, Nanjing Normal University, Nanjing, China
| | - Lin Zhou
- School of Chemistry and Bioengineering, Nanjing Normal University Taizhou College, Taizhou, China
| | - Yinghui Liu
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Sciences, Nanjing Normal University, Nanjing, China.
| | - Haijia Yu
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Sciences, Nanjing Normal University, Nanjing, China.
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10
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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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11
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Zhou HL, Premont RT, Stamler JS. The manifold roles of protein S-nitrosylation in the life of insulin. Nat Rev Endocrinol 2022; 18:111-128. [PMID: 34789923 PMCID: PMC8889587 DOI: 10.1038/s41574-021-00583-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 10/08/2021] [Indexed: 02/04/2023]
Abstract
Insulin, which is released by pancreatic islet β-cells in response to elevated levels of glucose in the blood, is a critical regulator of metabolism. Insulin triggers the uptake of glucose and fatty acids into the liver, adipose tissue and muscle, and promotes the storage of these nutrients in the form of glycogen and lipids. Dysregulation of insulin synthesis, secretion, transport, degradation or signal transduction all cause failure to take up and store nutrients, resulting in type 1 diabetes mellitus, type 2 diabetes mellitus and metabolic dysfunction. In this Review, we make the case that insulin signalling is intimately coupled to protein S-nitrosylation, in which nitric oxide groups are conjugated to cysteine thiols to form S-nitrosothiols, within effectors of insulin action. We discuss the role of S-nitrosylation in the life cycle of insulin, from its synthesis and secretion in pancreatic β-cells, to its signalling and degradation in target tissues. Finally, we consider how aberrant S-nitrosylation contributes to metabolic diseases, including the roles of human genetic mutations and cellular events that alter S-nitrosylation of insulin-regulating proteins. Given the growing influence of S-nitrosylation in cellular metabolism, the field of metabolic signalling could benefit from renewed focus on S-nitrosylation in type 2 diabetes mellitus and insulin-related disorders.
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Affiliation(s)
- Hua-Lin Zhou
- Department of Medicine, Case Western Reserve University School of Medicine, Cleveland, OH, USA
- Institute for Transformative Molecular Medicine, Case Western Reserve University School of Medicine, Cleveland, OH, USA
- Harrington Discovery Institute, University Hospitals Cleveland Medical Center, Cleveland, OH, USA
| | - Richard T Premont
- Department of Medicine, Case Western Reserve University School of Medicine, Cleveland, OH, USA
- Institute for Transformative Molecular Medicine, Case Western Reserve University School of Medicine, Cleveland, OH, USA
- Harrington Discovery Institute, University Hospitals Cleveland Medical Center, Cleveland, OH, USA
| | - Jonathan S Stamler
- Department of Medicine, Case Western Reserve University School of Medicine, Cleveland, OH, USA.
- Institute for Transformative Molecular Medicine, Case Western Reserve University School of Medicine, Cleveland, OH, USA.
- Harrington Discovery Institute, University Hospitals Cleveland Medical Center, Cleveland, OH, USA.
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12
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Ouahed J, Kelsen JR, Spessott WA, Kooshesh K, Sanmillan ML, Dawany N, Sullivan KE, Hamilton KE, Slowik V, Nejentsev S, Neves JF, Flores H, Chung WK, Wilson A, Anyane-Yeboa K, Wou K, Jain P, Field M, Tollefson S, Dent MH, Li D, Naito T, McGovern DPB, Kwong AC, Taliaferro F, Ordovas-Montanes J, Horwitz BH, Kotlarz D, Klein C, Evans J, Dorsey J, Warner N, Elkadri A, Muise AM, Goldsmith J, Thompson B, Engelhardt KR, Cant AJ, Hambleton S, Barclay A, Toth-Petroczy A, Vuzman D, Carmichael N, Bodea C, Cassa CA, Devoto M, Maas RL, Behrens EM, Giraudo CG, Snapper SB. Variants in STXBP3 are Associated with Very Early Onset Inflammatory Bowel Disease, Bilateral Sensorineural Hearing Loss and Immune Dysregulation. J Crohns Colitis 2021; 15:1908-1919. [PMID: 33891011 PMCID: PMC8575043 DOI: 10.1093/ecco-jcc/jjab077] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
BACKGROUND AND AIMS Very early onset inflammatory bowel disease [VEOIBD] is characterized by intestinal inflammation affecting infants and children less than 6 years of age. To date, over 60 monogenic aetiologies of VEOIBD have been identified, many characterized by highly penetrant recessive or dominant variants in underlying immune and/or epithelial pathways. We sought to identify the genetic cause of VEOIBD in a subset of patients with a unique clinical presentation. METHODS Whole exome sequencing was performed on five families with ten patients who presented with a similar constellation of symptoms including medically refractory infantile-onset IBD, bilateral sensorineural hearing loss and, in the majority, recurrent infections. Genetic aetiologies of VEOIBD were assessed and Sanger sequencing was performed to confirm novel genetic findings. Western analysis on peripheral blood mononuclear cells and functional studies with epithelial cell lines were employed. RESULTS In each of the ten patients, we identified damaging heterozygous or biallelic variants in the Syntaxin-Binding Protein 3 gene [STXBP3], a protein known to regulate intracellular vesicular trafficking in the syntaxin-binding protein family of molecules, but not associated to date with either VEOIBD or sensorineural hearing loss. These mutations interfere with either intron splicing or protein stability and lead to reduced STXBP3 protein expression. Knock-down of STXBP3 in CaCo2 cells resulted in defects in cell polarity. CONCLUSION Overall, we describe a novel genetic syndrome and identify a critical role for STXBP3 in VEOIBD, sensorineural hearing loss and immune dysregulation.
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Affiliation(s)
- Jodie Ouahed
- Division of Gastroenterology, Hepatology, and Nutrition, Department of Pediatrics, Boston Children's Hospital, and Harvard Medical School, Boston, MA, 02115, USA
| | - Judith R Kelsen
- Division of Gastroenterology, Hepatology, and Nutrition, The Children's Hospital of Philadelphia, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Waldo A Spessott
- Department of Microbiology and Immunology, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA, 19107, USA
| | - Kameron Kooshesh
- Brigham Genomic Medicine Program, Division of Genetics, Department of Medicine, Brigham & Women's Hospital and Harvard Medical School, Boston, MA, 02115, USA
| | - Maria L Sanmillan
- Department of Microbiology and Immunology, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA, 19107, USA
| | - Noor Dawany
- Department of Biomedical Health Informatics, The Children's Hospital of Philadelphia, Philadelphia, PA, 19104, USA
| | - Kathleen E Sullivan
- Division of Allergy and Immunology, The Children's Hospital of Philadelphia, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Kathryn E Hamilton
- Division of Gastroenterology, Hepatology, and Nutrition, The Children's Hospital of Philadelphia, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Voytek Slowik
- Department of Medicine, Division of Gastroenterology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Sergey Nejentsev
- Division of Gastroenterology, Hepatology, and Nutrition, Children's Mercy Kansas City, Kansas City, MO, 64108, USA.,Department of Medicine, University of Cambridge, Cambridge, CB2 0QQ, UK
| | - João Farela Neves
- Department of Molecular Cell Biology and Immunology, Amsterdam University Medical Centers, Amsterdam, the Netherlands.,Primary Immunodeficiencies Unit; Hospital Dona Estefânia-CHLC, EPE, Lisbon, 1169, Portugal
| | - Helena Flores
- CEDOC, Chronic Diseases Research Center, NOVA Medical School, Lisbon, 1150, Portugal
| | - Wendy K Chung
- Gastroenterology Unit, Hospital Dona Estefânia-CHLC, EPE, Lisbon, 1169, Portugal
| | - Ashley Wilson
- Gastroenterology Unit, Hospital Dona Estefânia-CHLC, EPE, Lisbon, 1169, Portugal
| | - Kwame Anyane-Yeboa
- Gastroenterology Unit, Hospital Dona Estefânia-CHLC, EPE, Lisbon, 1169, Portugal
| | - Karen Wou
- Gastroenterology Unit, Hospital Dona Estefânia-CHLC, EPE, Lisbon, 1169, Portugal
| | - Preti Jain
- Department of Pediatrics, Columbia University Medical Center, New York, NY, 10032, USA.,Department of Medicine, Columbia University Medical Center, New York, NY, 10032, USA
| | - Michael Field
- Division of Gastroenterology, Hepatology, and Nutrition, Department of Pediatrics, Boston Children's Hospital, and Harvard Medical School, Boston, MA, 02115, USA
| | - Sophia Tollefson
- Division of Gastroenterology, Hepatology, and Nutrition, Department of Pediatrics, Boston Children's Hospital, and Harvard Medical School, Boston, MA, 02115, USA
| | - Maiah H Dent
- Department of Genetics, Yale University, New Haven, CT, 06510, USA
| | - Dalin Li
- F. Widjaja Foundation Inflammatory Bowel and Immunobiology Research Institute, Cedars-Sinai Medical Center, Los Angeles, CA, 90048, USA
| | - Takeo Naito
- F. Widjaja Foundation Inflammatory Bowel and Immunobiology Research Institute, Cedars-Sinai Medical Center, Los Angeles, CA, 90048, USA
| | - Dermot P B McGovern
- F. Widjaja Foundation Inflammatory Bowel and Immunobiology Research Institute, Cedars-Sinai Medical Center, Los Angeles, CA, 90048, USA
| | - Andrew C Kwong
- Division of Gastroenterology, Hepatology, and Nutrition, Department of Pediatrics, Boston Children's Hospital, and Harvard Medical School, Boston, MA, 02115, USA.,Biological and Biomedical Sciences, Harvard Medical School, Boston, MA, 02115, USA.,Broad Institute of MIT and Harvard, Cambridge, MA, 02142, USA
| | - Faith Taliaferro
- Division of Gastroenterology, Hepatology, and Nutrition, Department of Pediatrics, Boston Children's Hospital, and Harvard Medical School, Boston, MA, 02115, USA.,Broad Institute of MIT and Harvard, Cambridge, MA, 02142, USA
| | - Jose Ordovas-Montanes
- Division of Gastroenterology, Hepatology, and Nutrition, Department of Pediatrics, Boston Children's Hospital, and Harvard Medical School, Boston, MA, 02115, USA.,Broad Institute of MIT and Harvard, Cambridge, MA, 02142, USA.,Program in Immunology, Harvard Medical School, Boston, MA, 02115, USA.,Harvard Stem Cell Institute, Cambridge, MA, 02138, USA
| | - Bruce H Horwitz
- Division of Gastroenterology, Hepatology, and Nutrition, Department of Pediatrics, Boston Children's Hospital, and Harvard Medical School, Boston, MA, 02115, USA.,Division of Emergency Medicine, Department of Pediatrics, Boston Children's Hospital, and Harvard Medical School, Boston, MA, 02115, USA
| | - Daniel Kotlarz
- Division of Gastroenterology, Hepatology, and Nutrition, Department of Pediatrics, Boston Children's Hospital, and Harvard Medical School, Boston, MA, 02115, USA.,Dr. von Hauner Children's Hospital, Department of Pediatrics, University Hospital LMU Munich, Munich, 80337, Germany
| | - Christoph Klein
- Dr. von Hauner Children's Hospital, Department of Pediatrics, University Hospital LMU Munich, Munich, 80337, Germany
| | - Jonathan Evans
- Department of Pediatrics, Nemours Children's Specialty Care, Jacksonville, FL 32207, USA
| | - Jill Dorsey
- Department of Pediatrics, Nemours Children's Specialty Care, Jacksonville, FL 32207, USA
| | - Neil Warner
- SickKids Inflammatory Bowel Disease Center and Cell Biology Program, Research Institute, Hospital for Sick Children, Toronto, ON, Canada.,Department of Pediatrics and Biochemistry, University of Toronto, Hospital for Sick Children, Toronto, ON, M5G 1X8, Canada
| | - Abdul Elkadri
- SickKids Inflammatory Bowel Disease Center and Cell Biology Program, Research Institute, Hospital for Sick Children, Toronto, ON, Canada.,Department of Pediatrics and Biochemistry, University of Toronto, Hospital for Sick Children, Toronto, ON, M5G 1X8, Canada
| | - Aleixo M Muise
- SickKids Inflammatory Bowel Disease Center and Cell Biology Program, Research Institute, Hospital for Sick Children, Toronto, ON, Canada.,Department of Pediatrics and Biochemistry, University of Toronto, Hospital for Sick Children, Toronto, ON, M5G 1X8, Canada
| | - Jeffrey Goldsmith
- Department of Pathology, Boston Children's Hospital, Harvard Medical School, Boston, MA, 02115, USA
| | - Benjamin Thompson
- Primary Immunodeficiency Group, III Theme, Institute of Cellular Medicine, Newcastle University, Newcastle, NE2 4HH, UK
| | - Karin R Engelhardt
- Primary Immunodeficiency Group, III Theme, Institute of Cellular Medicine, Newcastle University, Newcastle, NE2 4HH, UK
| | - Andrew J Cant
- Primary Immunodeficiency Group, III Theme, Institute of Cellular Medicine, Newcastle University, Newcastle, NE2 4HH, UK.,Children's Immunology Service, Great North Children's Hospital, Newcastle upon Tyne Hospitals NHS Foundation Trust, Newcastle, NE1 4LP, UK
| | - Sophie Hambleton
- Primary Immunodeficiency Group, III Theme, Institute of Cellular Medicine, Newcastle University, Newcastle, NE2 4HH, UK.,Children's Immunology Service, Great North Children's Hospital, Newcastle upon Tyne Hospitals NHS Foundation Trust, Newcastle, NE1 4LP, UK
| | - Andrew Barclay
- Department of Paediatric Gastroenterology, Royal Hospital for Children, Glasgow, G51 4TF, UK
| | - Agnes Toth-Petroczy
- Brigham Genomic Medicine Program, Division of Genetics, Department of Medicine, Brigham & Women's Hospital and Harvard Medical School, Boston, MA, 02115, USA.,Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany.,Center for Systems Biology Dresden, Dresden, Germany
| | - Dana Vuzman
- Brigham Genomic Medicine Program, Division of Genetics, Department of Medicine, Brigham & Women's Hospital and Harvard Medical School, Boston, MA, 02115, USA
| | - Nikkola Carmichael
- Brigham Genomic Medicine Program, Division of Genetics, Department of Medicine, Brigham & Women's Hospital and Harvard Medical School, Boston, MA, 02115, USA
| | - Corneliu Bodea
- Brigham Genomic Medicine Program, Division of Genetics, Department of Medicine, Brigham & Women's Hospital and Harvard Medical School, Boston, MA, 02115, USA
| | - Christopher A Cassa
- Brigham Genomic Medicine Program, Division of Genetics, Department of Medicine, Brigham & Women's Hospital and Harvard Medical School, Boston, MA, 02115, USA
| | - Marcella Devoto
- Division of Human Genetics, The Children's Hospital of Philadelphia, Department of Pediatrics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.,Department of Translational and Precision Medicine, University Sapienza, Rome 00185, Italy.,CNR-IRGB, Cagliari 09042, Italy
| | - Richard L Maas
- Brigham Genomic Medicine Program, Division of Genetics, Department of Medicine, Brigham & Women's Hospital and Harvard Medical School, Boston, MA, 02115, USA
| | - Edward M Behrens
- Division of Rheumatology, The Children's Hospital of Philadelphia, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Claudio G Giraudo
- Department of Microbiology and Immunology, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA, 19107, USA
| | - Scott B Snapper
- Division of Gastroenterology, Hepatology, and Nutrition, Department of Pediatrics, Boston Children's Hospital, and Harvard Medical School, Boston, MA, 02115, USA.,Division of Gastroenterology, Department of Medicine, Brigham & Women's Hospital and Harvard Medical School, Boston, MA, 02115, USA
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13
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Lenz D, Pahl J, Hauck F, Alameer S, Balasubramanian M, Baric I, Boy N, Church JA, Crushell E, Dick A, Distelmaier F, Gujar J, Indolfi G, Lurz E, Peters B, Schwerd T, Serranti D, Kölker S, Klein C, Hoffmann GF, Prokisch H, Greil J, Cerwenka A, Giese T, Staufner C. NBAS Variants Are Associated with Quantitative and Qualitative NK and B Cell Deficiency. J Clin Immunol 2021; 41:1781-1793. [PMID: 34386911 PMCID: PMC8604887 DOI: 10.1007/s10875-021-01110-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2021] [Accepted: 07/23/2021] [Indexed: 12/30/2022]
Abstract
PURPOSE Biallelic pathogenic NBAS variants manifest as a multisystem disorder with heterogeneous clinical phenotypes such as recurrent acute liver failure, growth retardation, and susceptibility to infections. This study explores how NBAS-associated disease affects cells of the innate and adaptive immune system. METHODS Clinical and laboratory parameters were combined with functional multi-parametric immunophenotyping methods in fifteen NBAS-deficient patients to discover possible alterations in their immune system. RESULTS Our study revealed reduced absolute numbers of mature CD56dim natural killer (NK) cells. Notably, the residual NK cell population in NBAS-deficient patients exerted a lower potential for activation and degranulation in response to K562 target cells, suggesting an NK cell-intrinsic role for NBAS in the release of cytotoxic granules. NBAS-deficient NK cell activation and degranulation was normalized upon pre-activation by IL-2 in vitro, suggesting that functional impairment was reversible. In addition, we observed a reduced number of naïve B cells in the peripheral blood associated with hypogammaglobulinemia. CONCLUSION In summary, we demonstrate that pathogenic biallelic variants in NBAS are associated with dysfunctional NK cells as well as impaired adaptive humoral immunity.
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Affiliation(s)
- Dominic Lenz
- Division of Neuropediatrics and Pediatric Metabolic Medicine, Center for Pediatric and Adolescent Medicine, University Hospital Heidelberg, Im Neuenheimer Feld 430, 69120, Heidelberg, Germany
| | - Jens Pahl
- Department of Immunobiochemistry, Mannheim Institute for Innate Immunoscience (MI3), Medizinische Fakultät Mannheim, Universität Heidelberg, Mannheim, Germany
| | - Fabian Hauck
- Department of Pediatrics, Dr. Von Hauner Children's Hospital, University Hospital, Ludwig-Maximilians-Universität München (LMU), Munich, Germany
- German Centre for Infection Research (DZIF), Munich, Germany
- Munich Centre for Rare Diseases (M-ZSELMU), University Hospital, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Seham Alameer
- Pediatric Department, Ministry of National Guard Health Affairs, Jeddah, Saudi Arabia
- King Abdullah International Medical Research Center, Jeddah, Saudi Arabia
- King Saud Bin Abdulaziz University for Health Sciences, Jeddah, Saudi Arabia
| | - Meena Balasubramanian
- Sheffield Clinical Genetics Service, Sheffield Children's NHS Foundation Trust, Sheffield, UK
- Department of Oncology & Metabolism, University of Sheffield, Sheffield, UK
| | - Ivo Baric
- Department of Pediatrics, School of Medicine, University Hospital Center Zagreb and University of Zagreb, Zagreb, Croatia
| | - Nikolas Boy
- Division of Neuropediatrics and Pediatric Metabolic Medicine, Center for Pediatric and Adolescent Medicine, University Hospital Heidelberg, Im Neuenheimer Feld 430, 69120, Heidelberg, Germany
| | - Joseph A Church
- Department of Pediatrics, Keck School of Medicine of the University of Southern California, and Children's Hospital Los Angeles, Los Angeles, CA, USA
| | - Ellen Crushell
- National Centre for Inherited Metabolic Disorders, Children's Health Ireland At Temple Street and Crumlin, Dublin, Ireland
| | - Anke Dick
- Department of Pediatrics, University Hospital Würzburg, Würzburg, Germany
| | - Felix Distelmaier
- Department of General Pediatrics, Neonatology and Pediatric Cardiology, University Children's Hospital, Heinrich-Heine-University Düsseldorf, Düsseldorf, Germany
| | - Jidnyasa Gujar
- Division of Neuropediatrics and Pediatric Metabolic Medicine, Center for Pediatric and Adolescent Medicine, University Hospital Heidelberg, Im Neuenheimer Feld 430, 69120, Heidelberg, Germany
| | - Giuseppe Indolfi
- Paediatric and Liver Unit, Meyer Children's University Hospital of Florence, Firenze, Italy
| | - Eberhard Lurz
- Department of Pediatrics, Dr. Von Hauner Children's Hospital, University Hospital, Ludwig-Maximilians-Universität München (LMU), Munich, Germany
| | - Bianca Peters
- Division of Neuropediatrics and Pediatric Metabolic Medicine, Center for Pediatric and Adolescent Medicine, University Hospital Heidelberg, Im Neuenheimer Feld 430, 69120, Heidelberg, Germany
| | - Tobias Schwerd
- Department of Pediatrics, Dr. Von Hauner Children's Hospital, University Hospital, Ludwig-Maximilians-Universität München (LMU), Munich, Germany
| | - Daniele Serranti
- Paediatric and Liver Unit, Meyer Children's University Hospital of Florence, Firenze, Italy
| | - Stefan Kölker
- Division of Neuropediatrics and Pediatric Metabolic Medicine, Center for Pediatric and Adolescent Medicine, University Hospital Heidelberg, Im Neuenheimer Feld 430, 69120, Heidelberg, Germany
| | - Christoph Klein
- Department of Pediatrics, Dr. Von Hauner Children's Hospital, University Hospital, Ludwig-Maximilians-Universität München (LMU), Munich, Germany
- German Centre for Infection Research (DZIF), Munich, Germany
- Munich Centre for Rare Diseases (M-ZSELMU), University Hospital, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Georg F Hoffmann
- Division of Neuropediatrics and Pediatric Metabolic Medicine, Center for Pediatric and Adolescent Medicine, University Hospital Heidelberg, Im Neuenheimer Feld 430, 69120, Heidelberg, Germany
| | - Holger Prokisch
- Institute of Human Genetics, Klinikum Rechts Der Isar, Technical University of Munich, Munich, Germany
- Institute of Human Genetics, Helmholtz Zentrum Munich, Neuherberg, Germany
| | - Johann Greil
- Department of Pediatric Hematology and Oncology, University Children's Hospital, Heidelberg, Germany
| | - Adelheid Cerwenka
- Department of Immunobiochemistry, Mannheim Institute for Innate Immunoscience (MI3), Medizinische Fakultät Mannheim, Universität Heidelberg, Mannheim, Germany
| | - Thomas Giese
- Institute of Immunology and German Center for Infection Research (DZIF), Heidelberg University Hospital, Heidelberg, Germany
| | - Christian Staufner
- Division of Neuropediatrics and Pediatric Metabolic Medicine, Center for Pediatric and Adolescent Medicine, University Hospital Heidelberg, Im Neuenheimer Feld 430, 69120, Heidelberg, Germany.
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14
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Asadi F, Dhanvantari S. Pathways of Glucagon Secretion and Trafficking in the Pancreatic Alpha Cell: Novel Pathways, Proteins, and Targets for Hyperglucagonemia. Front Endocrinol (Lausanne) 2021; 12:726368. [PMID: 34659118 PMCID: PMC8511682 DOI: 10.3389/fendo.2021.726368] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Accepted: 09/13/2021] [Indexed: 12/15/2022] Open
Abstract
Patients with diabetes mellitus exhibit hyperglucagonemia, or excess glucagon secretion, which may be the underlying cause of the hyperglycemia of diabetes. Defective alpha cell secretory responses to glucose and paracrine effectors in both Type 1 and Type 2 diabetes may drive the development of hyperglucagonemia. Therefore, uncovering the mechanisms that regulate glucagon secretion from the pancreatic alpha cell is critical for developing improved treatments for diabetes. In this review, we focus on aspects of alpha cell biology for possible mechanisms for alpha cell dysfunction in diabetes: proglucagon processing, intrinsic and paracrine control of glucagon secretion, secretory granule dynamics, and alterations in intracellular trafficking. We explore possible clues gleaned from these studies in how inhibition of glucagon secretion can be targeted as a treatment for diabetes mellitus.
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Affiliation(s)
- Farzad Asadi
- Department of Pathology and Laboratory Medicine, Western University, London, ON, Canada
- Program in Metabolism and Diabetes, Lawson Health Research Institute, London, ON, Canada
| | - Savita Dhanvantari
- Department of Pathology and Laboratory Medicine, Western University, London, ON, Canada
- Program in Metabolism and Diabetes, Lawson Health Research Institute, London, ON, Canada
- Imaging Research Program, Lawson Health Research Institute, London, ON, Canada
- Department of Medical Biophysics, Western University, London, ON, Canada
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15
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Hu R, Zhu X, Yuan M, Ho KH, Kaverina I, Gu G. Microtubules and Gαo-signaling modulate the preferential secretion of young insulin secretory granules in islet β cells via independent pathways. PLoS One 2021; 16:e0241939. [PMID: 34292976 PMCID: PMC8297875 DOI: 10.1371/journal.pone.0241939] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2020] [Accepted: 06/15/2021] [Indexed: 12/24/2022] Open
Abstract
For sustainable function, each pancreatic islet β cell maintains thousands of insulin secretory granules (SGs) at all times. Glucose stimulation induces the secretion of a small portion of these SGs and simultaneously boosts SG biosynthesis to sustain this stock. The failure of these processes, often induced by sustained high-insulin output, results in type 2 diabetes. Intriguingly, young insulin SGs are more likely secreted during glucose-stimulated insulin secretion (GSIS) for unknown reasons, while older SGs tend to lose releasability and be degraded. Here, we examine the roles of microtubule (MT) and Gαo-signaling in regulating the preferential secretion of young versus old SGs. We show that both MT-destabilization and Gαo inactivation results in more SGs localization near plasma membrane (PM) despite higher levels of GSIS and reduced SG biosynthesis. Intriguingly, MT-destabilization or Gαo-inactivation results in higher secretion probabilities of older SGs, while combining both having additive effects on boosting GSIS. Lastly, Gαo inactivation does not detectably destabilize the β-cell MT network. These findings suggest that Gαo and MT can modulate the preferential release of younger insulin SGs via largely parallel pathways.
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Affiliation(s)
- Ruiying Hu
- Department of Cell and Developmental Biology, The Program of Developmental Biology and the Center for Stem Cell Biology, Vanderbilt University, Nashville, TN, United States of America
| | - Xiaodong Zhu
- Department of Cell and Developmental Biology, The Program of Developmental Biology and the Center for Stem Cell Biology, Vanderbilt University, Nashville, TN, United States of America
| | - Mingyang Yuan
- Department of Cell and Developmental Biology, The Program of Developmental Biology and the Center for Stem Cell Biology, Vanderbilt University, Nashville, TN, United States of America
| | - Kung-Hsien Ho
- Department of Cell and Developmental Biology, The Program of Developmental Biology and the Center for Stem Cell Biology, Vanderbilt University, Nashville, TN, United States of America
| | - Irina Kaverina
- Department of Cell and Developmental Biology, The Program of Developmental Biology and the Center for Stem Cell Biology, Vanderbilt University, Nashville, TN, United States of America
- * E-mail: (GG); (IK)
| | - Guoqiang Gu
- Department of Cell and Developmental Biology, The Program of Developmental Biology and the Center for Stem Cell Biology, Vanderbilt University, Nashville, TN, United States of America
- * E-mail: (GG); (IK)
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16
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Alhendi ASN, Lim D, McKee S, McEntagart M, Tatton-Brown K, Temple IK, Davies JH, Mackay DJG. Whole-genome analysis as a diagnostic tool for patients referred for diagnosis of Silver-Russell syndrome: a real-world study. J Med Genet 2021; 59:613-622. [PMID: 34135092 DOI: 10.1136/jmedgenet-2021-107699] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2021] [Accepted: 05/06/2021] [Indexed: 02/01/2023]
Abstract
BACKGROUND Silver-Russell syndrome (SRS) is an imprinting disorder characterised by prenatal and postnatal growth restriction, but its clinical features are non-specific and its differential diagnosis is broad. Known molecular causes of SRS include imprinting disturbance, single nucleotide variant (SNV), CNV or UPD affecting several genes; however, up to 40% of individuals with a clinical diagnosis of SRS currently receive no positive molecular diagnosis. METHODS To determine whether whole-genome sequencing (WGS) could uncover pathogenic variants missed by current molecular testing, we analysed data of 72 participants recruited to the 100,000 Genomes Project within the clinical category of SRS. RESULTS In 20 participants (27% of the cohort) we identified genetic variants plausibly accounting for SRS. Coding SNVs were identified in genes including CDKN1C, IGF2, IGF1R and ORC1. Maternal-effect variants were found in mothers of five participants, including two participants with imprinting disturbance and one with multilocus imprinting disorder. Two regions of homozygosity were suggestive of UPD involving imprinted regions implicated in SRS and Temple syndrome, and three plausibly pathogenic CNVs were found, including a paternal deletion of PLAGL1. In 48 participants with no plausible pathogenic variant, unbiased analysis of SNVs detected a potential association with STX4. CONCLUSION WGS analysis can detect UPD, CNV and SNV and is potentially a valuable addition to diagnosis of SRS and related growth-restricting disorders.
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Affiliation(s)
- Ahmed S N Alhendi
- Human Genetics and Genomic Medicine, Faculty of Medicine, University Hospital Southampton NHS Foundation Trust, Southampton, UK
| | - Derek Lim
- Department of Clinical Genetics, Birmingham Women's and Children's Hospital, Birmingham, UK
| | - Shane McKee
- Department of Genetic Medicine, Belfast City Hospital, Belfast, UK
| | - Meriel McEntagart
- Department of Clinical Genetics, St George's Healthcare NHS Trust, London, UK
| | | | - I Karen Temple
- Human Genetics and Genomic Medicine, Faculty of Medicine, University Hospital Southampton NHS Foundation Trust, Southampton, UK
| | - Justin H Davies
- Human Genetics and Genomic Medicine, Faculty of Medicine, University Hospital Southampton NHS Foundation Trust, Southampton, UK
| | - Deborah J G Mackay
- Human Genetics and Genomic Medicine, Faculty of Medicine, University Hospital Southampton NHS Foundation Trust, Southampton, UK .,Wessex Regional Genetics Laboratory, Salisbury NHS Foundation Trust, Salisbury, UK
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17
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Excessive Iron Induces Oxidative Stress Promoting Cellular Perturbations and Insulin Secretory Dysfunction in MIN6 Beta Cells. Cells 2021; 10:cells10051141. [PMID: 34065122 PMCID: PMC8151797 DOI: 10.3390/cells10051141] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2021] [Revised: 05/05/2021] [Accepted: 05/06/2021] [Indexed: 12/25/2022] Open
Abstract
Exposure to high levels of glucose and iron are co-related to reactive oxygen species (ROS) generation and dysregulation of insulin synthesis and secretion, although the precise mechanisms are not well clarified. The focus of this study was to examine the consequences of exposure to high iron levels on MIN6 β-cells. MIN6 pseudoislets were exposed to 20 µM (control) or 100 µM (high) iron at predefined glucose levels (5.5 mM and 11 mM) at various time points (3, 24, 48, and 72 h). Total iron content was estimated by a colourimetric FerroZine™ assay in presence or absence of transferrin-bound iron. Cell viability was assessed by a resazurin dye-based assay, and ROS-mediated cellular oxidative stress was assessed by estimating malondialdehyde levels. β-cell iron absorption was determined by a ferritin immunoassay. Cellular insulin release and content was measured by an insulin immunoassay. Expression of SNAP-25, a key protein in the core SNARE complex that modulates vesicle exocytosis, was measured by immunoblotting. Our results demonstrate that exposure to high iron levels resulted in a 15-fold (48 h) and 4-fold (72 h) increase in cellular iron accumulation. These observations were consistent with data from oxidative stress analysis which demonstrated 2.7-fold higher levels of lipid peroxidation. Furthermore, exposure to supraphysiological (11 mM) levels of glucose and high iron (100 µM) at 72 h exerted the most detrimental effect on the MIN6 β-cell viability. The effect of high iron exposure on total cellular iron content was identical in the presence or absence of transferrin. High iron exposure (100 µM) resulted in a decrease of MIN6 insulin secretion (64% reduction) as well as cellular insulin content (10% reduction). Finally, a significant reduction in MIN6 β-cell SNAP-25 protein expression was evident at 48 h upon exposure to 100 µM iron. Our data suggest that exposure to high iron and glucose concentrations results in cellular oxidative damage and may initiate insulin secretory dysfunction in pancreatic β-cells by modulation of the exocytotic machinery.
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18
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Wang S, Liu Y, Crisman L, Wan C, Miller J, Yu H, Shen J. Genetic evidence for an inhibitory role of tomosyn in insulin-stimulated GLUT4 exocytosis. Traffic 2021; 21:636-646. [PMID: 32851733 DOI: 10.1111/tra.12760] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2020] [Revised: 08/21/2020] [Accepted: 08/22/2020] [Indexed: 12/11/2022]
Abstract
Exocytosis is a vesicle fusion process driven by soluble N-ethylmaleimide-sensitive factor attachment protein receptors (SNAREs). A classic exocytic pathway is insulin-stimulated translocation of the glucose transporter type 4 (GLUT4) from intracellular vesicles to the plasma membrane in adipocytes and skeletal muscles. The GLUT4 exocytic pathway plays a central role in maintaining blood glucose homeostasis and is compromised in insulin resistance and type 2 diabetes. A candidate regulator of GLUT4 exocytosis is tomosyn, a soluble protein expressed in adipocytes. Tomosyn directly binds to GLUT4 exocytic SNAREs in vitro but its role in GLUT4 exocytosis was unknown. In this work, we used CRISPR-Cas9 genome editing to delete the two tomosyn-encoding genes in adipocytes. We observed that both basal and insulin-stimulated GLUT4 exocytosis was markedly elevated in the double knockout (DKO) cells. By contrast, adipocyte differentiation and insulin signaling remained intact in the DKO adipocytes. In a reconstituted liposome fusion assay, tomosyn inhibited all the SNARE complexes underlying GLUT4 exocytosis. The inhibitory activity of tomosyn was relieved by NSF and α-SNAP, which act in concert to remove tomosyn from GLUT4 exocytic SNAREs. Together, these studies revealed an inhibitory role for tomosyn in insulin-stimulated GLUT4 exocytosis in adipocytes. We suggest that tomosyn-arrested SNAREs represent a reservoir of fusion capacity that could be harnessed to treat patients with insulin resistance and type 2 diabetes.
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Affiliation(s)
- Shifeng Wang
- Department of Molecular, Cellular and Developmental Biology, University of Colorado, Boulder, Colorado, USA.,Department of Chinese Medicine Information Science, Beijing University of Chinese Medicine, Beijing, China
| | - Yinghui Liu
- Department of Molecular, Cellular and Developmental Biology, University of Colorado, Boulder, Colorado, USA
| | - Lauren Crisman
- Department of Molecular, Cellular and Developmental Biology, University of Colorado, Boulder, Colorado, USA
| | - Chun Wan
- Department of Molecular, Cellular and Developmental Biology, University of Colorado, Boulder, Colorado, USA
| | - Jessica Miller
- Department of Molecular, Cellular and Developmental Biology, University of Colorado, Boulder, Colorado, USA
| | - Haijia Yu
- Department of Molecular, Cellular and Developmental Biology, University of Colorado, Boulder, Colorado, USA
| | - Jingshi Shen
- Department of Molecular, Cellular and Developmental Biology, University of Colorado, Boulder, Colorado, USA
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19
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Kamga-Simo FDY, Kamatou GP, Ssemakalu C, Shai LJ. Cassia Abbreviata Enhances Glucose Uptake and Glucose Transporter 4 Translocation in C2C12 Mouse Skeletal Muscle Cells. J Evid Based Integr Med 2021; 26:2515690X211006333. [PMID: 33788626 PMCID: PMC8020231 DOI: 10.1177/2515690x211006333] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Background. This study aim at assessing C. abbreviata aqueous extracts for its potential to exhibit anti-diabetic activity in skeletal muscle cells. In addition to the toxicological and glucose absorption studies, the action of C. abbreviata extracts on some major genes involved in the insulin signaling pathway was established. Methods. The in vitro cytotoxic effects C. abbreviata was evaluated on muscle cells using the MTT assay and the in vitro glucose uptake assay conducted using a modified glucose oxidase method described by Van de Venter et al. (2008). The amount of GLUT-4 on cell surfaces was estimated quantitatively using the flow cytometry technique. Real time quantitative PCR (RT-qPCR) was used to determine the expression of GLUT-4, IRS-1, PI3 K, Akt1, Akt2, PPAR-γ. Results. Cytotoxicity tests revealed that all extracts tested at various concentrations were non-toxic (LC50 > 5000). Aqueous extracts of leaves, bark and seeds resulted in a dose-dependent increase in glucose absorption by cells, after 1 h, 3 h and 6 h incubation period. Extracts of all three plant parts had the best effect after 3 h incubation, with the leaf extract showing the best activity across time (Glucose uptake of 29%, 56% and 42% higher than untreated control cells after treatment with 1 mg/ml extract at 1 h, 3 h and 6 h, respectively). All extracts, with the exception 500 µg/ml seed extract, induced a two-fold increase in GLUT-4 translocation while marginally inducing GLUT-10 translocation in the muscle cells. The indirect immunofluorescence confirmed that GLUT-4 translocation indeed occurred. There was an increased expression of GLUT-4, IRS1 and PI3 K in cells treated with insulin and bark extract as determined by the RT-qPCR. Conclusion. The study reveals that glucose uptake involves GLUT-4 translocation through a mechanism that is likely to involve the upstream effectors of the PI3-K/Akt pathway.
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Affiliation(s)
- F D Y Kamga-Simo
- Department of Biomedical Sciences, Tshwane University of Technology, Private Bag Pretoria, South Africa
| | - G P Kamatou
- Department of Pharmaceutical Sciences, Tshwane University of Technology, Private Bag, Pretoria, South Africa
| | - C Ssemakalu
- Cell Biology Research Unit, Department of Biotechnology, Vaal University of Technology, Private Bag, Pretoria, South Africa
| | - L J Shai
- Department of Biomedical Sciences, Tshwane University of Technology, Private Bag Pretoria, South Africa
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20
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Tiliacora triandra (Colebr.) Diels Leaf Aqueous Extract Inhibits Hepatic Glucose Production in HepG2 Cells and Type 2 Diabetic Rats. Molecules 2021; 26:molecules26051239. [PMID: 33669133 PMCID: PMC7956658 DOI: 10.3390/molecules26051239] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Revised: 02/16/2021] [Accepted: 02/19/2021] [Indexed: 01/04/2023] Open
Abstract
This study investigated the effects of Tiliacora triandra (Colebr.) Diels aqueous extract (TTE) on hepatic glucose production in hepatocellular carcinoma (HepG2) cells and type 2 diabetic (T2DM) conditions. HepG2 cells were pretreated with TTE and its major constituents found in TTE, epicatechin (EC) and quercetin (QC). The hepatic glucose production was determined. The in vitro data were confirmed in T2DM rats, which were supplemented daily with 1000 mg/kg body weight (BW) TTE, 30 mg/kg BW metformin or TTE combined with metformin for 12 weeks. Results demonstrate that TTE induced copper-zinc superoxide dismutase, glutathione peroxidase and catalase genes, similarly to EC and QC. TTE decreased hepatic glucose production by downregulating phosphoenolpyruvate carboxykinase (PEPCK) and glucose-6-phosphatase (G6Pase) and increasing protein kinase B and AMP-activated protein kinase phosphorylation in HepG2 cells. These results correlated with the antihyperglycemic, antitriglyceridemic, anti-insulin resistance, and antioxidant activities of TTE in T2DM rats, similar to the metformin and combination treatments. Consistently, impairment of hepatic gluconeogenesis in T2DM rats was restored after single and combined treatments by reducing PEPCK and G6Pase genes. Collectively, TTE could potentially be developed as a nutraceutical product to prevent glucose overproduction in patients with obesity, insulin resistance, and diabetes who are being treated with antidiabetic drugs.
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21
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Gheibi S, Ghasemi A. Insulin secretion: The nitric oxide controversy. EXCLI JOURNAL 2020; 19:1227-1245. [PMID: 33088259 PMCID: PMC7573190 DOI: 10.17179/excli2020-2711] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/28/2020] [Accepted: 08/31/2020] [Indexed: 12/14/2022]
Abstract
Nitric oxide (NO) is a gas that serves as a ubiquitous signaling molecule participating in physiological activities of various organ systems. Nitric oxide is produced in the endocrine pancreas and contributes to synthesis and secretion of insulin. The potential role of NO in insulin secretion is disputable - both stimulatory and inhibitory effects have been reported. Available data indicate that effects of NO critically depend on its concentration. Different isoforms of NO synthase (NOS) control this and have the potential to decrease or increase insulin secretion. In this review, the role of NO in insulin secretion as well as the possible reasons for discrepant findings are discussed. A better understanding of the role of NO system in the regulation of insulin secretion may facilitate the development of new therapeutic strategies in the management of diabetes.
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Affiliation(s)
- Sevda Gheibi
- Department of Clinical Sciences in Malmö, Unit of Molecular Metabolism, Lund University Diabetes Centre, Clinical Research Center, Malmö University Hospital, Lund University, Malmö, Sweden
| | - Asghar Ghasemi
- Endocrine Physiology Research Center, Research Institute for Endocrine Sciences, Shahid Beheshti University of Medical Sciences, Tehran, Iran
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22
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Chen CC, Lii CK, Lin YH, Shie PH, Yang YC, Huang CS, Chen HW. Andrographis paniculata Improves Insulin Resistance in High-Fat Diet-Induced Obese Mice and TNFα-Treated 3T3-L1 Adipocytes. THE AMERICAN JOURNAL OF CHINESE MEDICINE 2020; 48:1073-1090. [DOI: 10.1142/s0192415x20500524] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Pro-inflammatory cytokines interfere with blood glucose homeostasis, which leads to hyperglycemia. Andrographis paniculata (AP) has been shown to possess anti-inflammatory activity and to reduce blood glucose levels in diabetes. The two major bioactive diterpenoids in AP, andrographolide (AND) and 14-deoxy-11,12-didehydroandrographolide (deAND), have potent anti-inflammatory activity. We studied whether APE (an ethanolic extract of AP), AND, and deAND could improve a high-fat diet (HFD)-induced hyperglycemia in vivo and TNF[Formula: see text]-induced impairment of insulin signaling in vitro. Male C57BL/6JNarl mice were fed a normal diet (ND) or the HFD, and the fatty mice were treated with APE, deAND, or AND for 16 weeks. 3T3-L1 cells were used to study the underlying mechanisms by which APE, deAND, or AND attenuated TNF[Formula: see text]-induced insulin resistance. The HFD significantly induced obesity, hyperglycemia, insulin resistance, and inflammation, whereas APE and deAND significantly ameliorated HFD-induced obesity, hyperglycemia, insulin resistance, and TNF[Formula: see text] production. The HFD significantly impaired insulin signaling by decreasing the protein expression of p-IRS1 tyr632 and p-AKT ser473, as well as the membrane translocation of GLUT4 in response to insulin stimulation in epididymal adipose tissue. HFD-impaired the membrane translocation of GLUT4 was significantly reversed by deAND and APE. In addition, deAND and APE markedly reversed the detrimental effect of TNF[Formula: see text] on the insulin signaling pathway and glucose uptake in 3T3-L1 cells. Despite no significant positive effect on p-AS160, a trend for recovery by deAND and APE was observed. These results suggest that deAND and APE protect against HFD-induced insulin resistance by ameliorating inflammation-driven impairment of insulin sensitivity.
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Affiliation(s)
- Chih-Chieh Chen
- Department of Nutrition, China Medical University, Taichung, Taiwan
| | - Chong-Kuei Lii
- Department of Nutrition, China Medical University, Taichung, Taiwan
- Department of Food Nutrition and Health Biotechnology, Asia University, Taichung, Taiwan
| | - Yi-Hsueh Lin
- Department of Nutrition, China Medical University, Taichung, Taiwan
| | - Pei-Hsin Shie
- Department of Nutrition, China Medical University, Taichung, Taiwan
| | - Ya-Chen Yang
- Department of Food Nutrition and Health Biotechnology, Asia University, Taichung, Taiwan
| | - Chin-Shiu Huang
- Department of Food Nutrition and Health Biotechnology, Asia University, Taichung, Taiwan
| | - Haw-Wen Chen
- Department of Nutrition, China Medical University, Taichung, Taiwan
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23
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Bittner T, Wittwer C, Hauke S, Wohlwend D, Mundinger S, Dutta AK, Bezold D, Dürr T, Friedrich T, Schultz C, Jessen HJ. Photolysis of Caged Inositol Pyrophosphate InsP 8 Directly Modulates Intracellular Ca 2+ Oscillations and Controls C2AB Domain Localization. J Am Chem Soc 2020; 142:10606-10611. [PMID: 32459478 DOI: 10.1021/jacs.0c01697] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Inositol pyrophosphates constitute a family of hyperphosphorylated signaling molecules involved in the regulation of glucose uptake and insulin sensitivity. While our understanding of the biological roles of inositol heptaphosphates (PP-InsP5) has greatly improved, the functions of the inositol octaphosphates ((PP)2-InsP4) have remained unclear. Here we present the synthesis of two enantiomeric cell-permeant and photocaged (PP)2-InsP4 derivatives and apply them to study the functions in living β-cells. Photorelease of the naturally occurring isomer 1,5-(PP)2-InsP4 led to an immediate and concentration-dependent reduction of intracellular calcium oscillations, while other caged inositol pyrophosphates (3,5-(PP)2-InsP4, 5-PP-InsP5, 1-PP-InsP5, 3-PP-InsP5) showed no immediate effect. Furthermore, uncaging of 1,5-(PP)2-InsP4 but not 3,5-(PP)2-InsP4 induced translocation of the C2AB domain of granuphilin from the plasma membrane to the cytosol. Granuphilin is involved in membrane docking of secretory vesicles. This suggests that 1,5-(PP)2-InsP4 impacts β-cell activity by regulating granule localization and/or priming and calcium signaling in concert.
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Affiliation(s)
- Tamara Bittner
- Department of Chemistry and Pharmacy, Albert-Ludwigs University Freiburg, Albertstrasse 21, 79104 Freiburg i.B., Germany
| | - Christopher Wittwer
- Department of Chemistry and Pharmacy, Albert-Ludwigs University Freiburg, Albertstrasse 21, 79104 Freiburg i.B., Germany
| | - Sebastian Hauke
- Cell Biology & Biophysics Unit, European Molecular Biology Laboratory (EMBL), Meyerhofstrasse 1, 69117 Heidelberg, Germany
| | - Daniel Wohlwend
- Department of Chemistry and Pharmacy, Albert-Ludwigs University Freiburg, Albertstrasse 21, 79104 Freiburg i.B., Germany
| | - Stephan Mundinger
- Department of Chemistry and Pharmacy, Albert-Ludwigs University Freiburg, Albertstrasse 21, 79104 Freiburg i.B., Germany
| | - Amit K Dutta
- Department of Chemistry and Pharmacy, Albert-Ludwigs University Freiburg, Albertstrasse 21, 79104 Freiburg i.B., Germany
| | - Dominik Bezold
- Department of Chemistry and Pharmacy, Albert-Ludwigs University Freiburg, Albertstrasse 21, 79104 Freiburg i.B., Germany
| | - Tobias Dürr
- Department of Chemistry and Pharmacy, Albert-Ludwigs University Freiburg, Albertstrasse 21, 79104 Freiburg i.B., Germany
| | - Thorsten Friedrich
- Department of Chemistry and Pharmacy, Albert-Ludwigs University Freiburg, Albertstrasse 21, 79104 Freiburg i.B., Germany
| | - Carsten Schultz
- Cell Biology & Biophysics Unit, European Molecular Biology Laboratory (EMBL), Meyerhofstrasse 1, 69117 Heidelberg, Germany.,Department of Chemical Physiology and Biochemistry, Oregon Health & Science University (OHSU), Sam Jackson Park Road, Portland, Oregon 97239-3098, United States
| | - Henning J Jessen
- Department of Chemistry and Pharmacy, Albert-Ludwigs University Freiburg, Albertstrasse 21, 79104 Freiburg i.B., Germany.,CIBSS-Centre for Integrative Biological Signalling Studies, 79104 Freiburg i.B., Germany.,Freiburg Research Institute for Advanced Studies (FRIAS), Albert-Ludwigs University Freiburg, Albertstrasse 19, 79104 Freiburg i.B., Germany
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24
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Thurmond DC, Gaisano HY. Recent Insights into Beta-cell Exocytosis in Type 2 Diabetes. J Mol Biol 2020; 432:1310-1325. [PMID: 31863749 PMCID: PMC8061716 DOI: 10.1016/j.jmb.2019.12.012] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2019] [Revised: 11/26/2019] [Accepted: 12/05/2019] [Indexed: 01/26/2023]
Abstract
As one of the leading causes of morbidity and mortality worldwide, diabetes affects an estimated 422 million adults, and it is expected to continue expanding such that by 2050, 30% of the U.S. population will become diabetic within their lifetime. Out of the estimated 422 million people currently afflicted with diabetes worldwide, about 5% have type 1 diabetes (T1D), while the remaining ~95% of diabetics have type 2 diabetes (T2D). Type 1 diabetes results from the autoimmune-mediated destruction of functional β-cell mass, whereas T2D results from combinatorial defects in functional β-cell mass plus peripheral glucose uptake. Both types of diabetes are now believed to be preceded by β-cell dysfunction. T2D is increasingly associated with numerous reports of deficiencies in the exocytosis proteins that regulate insulin release from β-cells, specifically the soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) proteins. SNARE protein's functionality is further regulated by a variety of accessory factors such as Sec1/Munc18 (SM), double C2-domain proteins (DOC2), and additional interacting proteins at the cell surface that influence the fidelity of insulin release. As new evidence emerges about the detailed mechanisms of exocytosis, new questions and controversies have come to light. This emerging information is also contributing to dialogue in the islet biology field focused on how to correct the defects in insulin exocytosis. Herein we present a balanced review of the role of exocytosis proteins in T2D, with thoughts on novel strategies to protect functional β-cell mass.
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Affiliation(s)
- Debbie C Thurmond
- Department of Molecular and Cellular Endocrinology, Beckman Research Institute of City of Hope, CA, USA.
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25
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Liang T, Qin T, Kang F, Kang Y, Xie L, Zhu D, Dolai S, Greitzer-Antes D, Baker RK, Feng D, Tuduri E, Ostenson CG, Kieffer TJ, Banks K, Pessin JE, Gaisano HY. SNAP23 depletion enables more SNAP25/calcium channel excitosome formation to increase insulin exocytosis in type 2 diabetes. JCI Insight 2020; 5:129694. [PMID: 32051343 PMCID: PMC7098801 DOI: 10.1172/jci.insight.129694] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2019] [Accepted: 01/15/2020] [Indexed: 01/05/2023] Open
Abstract
SNAP23 is the ubiquitous SNAP25 isoform that mediates secretion in non-neuronal cells, similar to SNAP25 in neurons. However, some secretory cells like pancreatic islet β cells contain an abundance of both SNAP25 and SNAP23, where SNAP23 is believed to play a redundant role to SNAP25. We show that SNAP23, when depleted in mouse β cells in vivo and human β cells (normal and type 2 diabetes [T2D] patients) in vitro, paradoxically increased biphasic glucose-stimulated insulin secretion corresponding to increased exocytosis of predocked and newcomer insulin granules. Such effects on T2D Goto-Kakizaki rats improved glucose homeostasis that was superior to conventional treatment with sulfonylurea glybenclamide. SNAP23, although fusion competent in slower secretory cells, in the context of β cells acts as a weak partial fusion agonist or inhibitory SNARE. Here, SNAP23 depletion promotes SNAP25 to bind calcium channels more quickly and longer where granule fusion occurs to increase exocytosis efficiency. β Cell SNAP23 antagonism is a strategy to treat diabetes.
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Affiliation(s)
- Tao Liang
- Department of Medicine, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Tairan Qin
- Department of Medicine, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Fei Kang
- Department of Medicine, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Youhou Kang
- Department of Medicine, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Li Xie
- Department of Medicine, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Dan Zhu
- Department of Medicine, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Subhankar Dolai
- Department of Medicine, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Dafna Greitzer-Antes
- Department of Medicine, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Robert K. Baker
- Department of Cellular and Physiological Sciences, Faculty of Medicine, University of British Columbia, Vancouver, British Columbia, Canada
| | - Daorong Feng
- Michael F. Price Center for Genetic and Translational Medicine, Department of Medicine and Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, New York, USA
| | - Eva Tuduri
- Department of Cellular and Physiological Sciences, Faculty of Medicine, University of British Columbia, Vancouver, British Columbia, Canada
| | - Claes-Goran Ostenson
- Department of Molecular Medicine and,Department of Surgery, Karolinska Institutet, Stockholm, Sweden
| | - Timothy J. Kieffer
- Department of Cellular and Physiological Sciences, Faculty of Medicine, University of British Columbia, Vancouver, British Columbia, Canada
| | - Kate Banks
- Division of Comparative Medicine, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Jeffrey E. Pessin
- Michael F. Price Center for Genetic and Translational Medicine, Department of Medicine and Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, New York, USA
| | - Herbert Y. Gaisano
- Department of Medicine, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
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26
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Li H, Park HM, Ji HS, Han J, Kim SK, Park HY, Jeong TS. Phenolic-enriched blueberry-leaf extract attenuates glucose homeostasis, pancreatic β-cell function, and insulin sensitivity in high-fat diet–induced diabetic mice. Nutr Res 2020; 73:83-96. [DOI: 10.1016/j.nutres.2019.09.005] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2019] [Revised: 09/11/2019] [Accepted: 09/16/2019] [Indexed: 12/26/2022]
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27
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Wang S, Crisman L, Miller J, Datta I, Gulbranson DR, Tian Y, Yin Q, Yu H, Shen J. Inducible Exoc7/Exo70 knockout reveals a critical role of the exocyst in insulin-regulated GLUT4 exocytosis. J Biol Chem 2019; 294:19988-19996. [PMID: 31740584 PMCID: PMC6937574 DOI: 10.1074/jbc.ra119.010821] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2019] [Revised: 11/13/2019] [Indexed: 12/20/2022] Open
Abstract
Insulin promotes glucose uptake by triggering the translocation of glucose transporter type 4 (GLUT4) from intracellular vesicles to the plasma membrane through exocytosis. GLUT4 exocytosis is a vesicle fusion event involving fusion of GLUT4-containing vesicles with the plasma membrane. For GLUT4 vesicle fusion to occur, GLUT4 vesicles must first be tethered to the plasma membrane. A key tethering factor in exocytosis is a heterooctameric protein complex called the exocyst. The role of the exocyst in GLUT4 exocytosis, however, remains incompletely understood. Here we first systematically analyzed data from a genome-scale CRISPR screen in HeLa cells that targeted virtually all known genes in the human genome, including 12 exocyst genes. The screen recovered only a subset of the exocyst genes, including exocyst complex component 7 (Exoc7/Exo70). Other exocyst genes, however, were not isolated in the screen, likely because of functional redundancy. Our findings suggest that selection of an appropriate exocyst gene is critical for genetic studies of exocyst functions. Next we developed an inducible adipocyte genome editing system that enabled Exoc7 gene deletion in adipocytes without interfering with adipocyte differentiation. We observed that insulin-stimulated GLUT4 exocytosis was markedly inhibited in Exoc7 KO adipocytes. Insulin signaling, however, remained intact in these KO cells. These results indicate that the exocyst plays a critical role in insulin-stimulated GLUT4 exocytosis in adipocytes. We propose that the strategy outlined in this work could be instrumental in genetically dissecting other membrane-trafficking pathways in adipocytes.
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Affiliation(s)
- Shifeng Wang
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado, Boulder, Colorado 80309
- Department of Chinese Medicine Information Science, Beijing University of Chinese Medicine, Beijing 102488, China
| | - Lauren Crisman
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado, Boulder, Colorado 80309
| | - Jessica Miller
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado, Boulder, Colorado 80309
| | - Ishara Datta
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado, Boulder, Colorado 80309
| | - Daniel R Gulbranson
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado, Boulder, Colorado 80309
| | - Yuan Tian
- Department of Biological Sciences and Institute of Molecular Biophysics, Florida State University, Tallahassee, Florida 32306
| | - Qian Yin
- Department of Biological Sciences and Institute of Molecular Biophysics, Florida State University, Tallahassee, Florida 32306
| | - Haijia Yu
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado, Boulder, Colorado 80309
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Sciences, Nanjing Normal University, Nanjing 210023, China
| | - Jingshi Shen
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado, Boulder, Colorado 80309
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The Potential of Hibiscus sabdariffa Linn in Inducing Glucagon-Like Peptide-1 via SGLT-1 and GLPR in DM Rats. BIOMED RESEARCH INTERNATIONAL 2019; 2019:8724824. [PMID: 31828140 PMCID: PMC6885171 DOI: 10.1155/2019/8724824] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/22/2019] [Accepted: 09/25/2019] [Indexed: 12/15/2022]
Abstract
Background Glucagon-like peptide 1 (GLP-1) hormone is an incretin hormone that is secreted in the ileum and plays a role in the pancreas to increase insulin secretion, stimulate proliferation, and prevent pancreatic β-cell apoptosis. Currently, diabetes mellitus (DM) treatment based on GLP-1 work is being developed, for instance, from herbal plants such as Hibiscus sabdariffa Linn (H. sabdariffa). Therefore, this study aims to determine the potential of H. sabdariffa in GLP-1 secretion in the ileum and its action in pancreatic β-cells. In addition, this study also aims to determine the active ingredients of H. sabdariffa (Hib) that interact with sodium-glucose cotransporter-1 (SGLT-1) so that it can increase GLP-1 secretion in the ileum and interact with GLP-1 receptors (GLP-1R) in the pancreas. Method This experimental study used 24 experimental animals of Sprague-Dawley type (aged 8-10 weeks, weight 200-250 g) that were divided into 6 groups, namely, (i) normal (C), (ii) normal-Hib 200 (C-Hib200), (iii) normal-Hib 500 (C-Hib500), (iv) DM (C-DM), (v) DM-Hib200, and (vi) DM-Hib500. H. sabdariffa extract was given orally once a day for 5 weeks. Testing of GLP-1 levels in the ileum and pancreatic tissue was performed by enzyme-linked immunosorbent assay. The prediction of the interaction mechanism of the active substance H. sabdariffa against GLP-1 was done using molecular docking. Results There was a decrease in GLP-1 levels in the ileum of DM rats (p < 0.05). However, DM rats administered H. sabdariffa 500 mg/kg BW had GLP-1 levels that were the same as in normal rats (p > 0.05). This is due to active ingredients such as leucosin, which binds to SGLT-1. Administration of 500 mg/kg BW H. sabdariffa in DM rats resulted in GLP-1 levels in the pancreas that were the same as in normal rats (p > 0.05). In addition, the active ingredient of H. sabdariffa, delphinidin, binds to GLPR in the pancreas. Conclusion The active ingredient of H. sabdariffa can increase GLP-1 secretion in the ileum and can interact with G protein-linked receptors in the pancreas.
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Gulbranson DR, Crisman L, Lee M, Ouyang Y, Menasche BL, Demmitt BA, Wan C, Nomura T, Ye Y, Yu H, Shen J. AAGAB Controls AP2 Adaptor Assembly in Clathrin-Mediated Endocytosis. Dev Cell 2019; 50:436-446.e5. [PMID: 31353312 DOI: 10.1016/j.devcel.2019.06.013] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2018] [Revised: 04/29/2019] [Accepted: 06/20/2019] [Indexed: 12/26/2022]
Abstract
Multimeric adaptors are broadly involved in vesicle-mediated membrane trafficking. AP2 adaptor, in particular, plays a central role in clathrin-mediated endocytosis (CME) by recruiting cargo and clathrin to endocytic sites. It is generally thought that trafficking adaptors such as AP2 adaptor assemble spontaneously. In this work, however, we discovered that AP2 adaptor assembly is an ordered process controlled by alpha and gamma adaptin binding protein (AAGAB), an uncharacterized factor identified in our genome-wide genetic screen of CME. AAGAB guides the sequential association of AP2 subunits and stabilizes assembly intermediates. Without the assistance of AAGAB, AP2 subunits fail to form the adaptor complex, leading to their degradation. The function of AAGAB is abrogated by a mutation that causes punctate palmoplantar keratoderma type 1 (PPKP1), a human skin disease. Since other multimeric trafficking adaptors operate in an analogous manner to AP2 adaptor, their assembly likely involves a similar regulatory mechanism.
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Affiliation(s)
- Daniel R Gulbranson
- Department of Molecular, Cellular and Developmental Biology, University of Colorado, Boulder, CO 80309, USA
| | - Lauren Crisman
- Department of Molecular, Cellular and Developmental Biology, University of Colorado, Boulder, CO 80309, USA
| | - MyeongSeon Lee
- Department of Molecular, Cellular and Developmental Biology, University of Colorado, Boulder, CO 80309, USA
| | - Yan Ouyang
- Department of Molecular, Cellular and Developmental Biology, University of Colorado, Boulder, CO 80309, USA
| | - Bridget L Menasche
- Department of Molecular, Cellular and Developmental Biology, University of Colorado, Boulder, CO 80309, USA
| | - Brittany A Demmitt
- Department of Molecular, Cellular and Developmental Biology, University of Colorado, Boulder, CO 80309, USA; Institute for Behavioral Genetics, University of Colorado, Boulder, CO 80309, USA
| | - Chun Wan
- Department of Molecular, Cellular and Developmental Biology, University of Colorado, Boulder, CO 80309, USA
| | - Toshifumi Nomura
- Department of Dermatology, Hokkaido University Graduate School of Medicine, Sapporo, Japan
| | - Yihong Ye
- Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Haijia Yu
- Department of Molecular, Cellular and Developmental Biology, University of Colorado, Boulder, CO 80309, USA; Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Sciences, Nanjing Normal University, Nanjing 210023, China.
| | - Jingshi Shen
- Department of Molecular, Cellular and Developmental Biology, University of Colorado, Boulder, CO 80309, USA.
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Hwang HJ, Jang HJ, Cocco L, Suh PG. The regulation of insulin secretion via phosphoinositide-specific phospholipase Cβ signaling. Adv Biol Regul 2019; 71:10-18. [PMID: 30293894 DOI: 10.1016/j.jbior.2018.09.011] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2018] [Revised: 09/17/2018] [Accepted: 09/17/2018] [Indexed: 06/08/2023]
Abstract
Phospholipase Cβ (PLCβ) is a membrane-associated enzyme activated by membrane receptors, especially G-protein coupled receptors (GPCRs). It propagates intracellular signaling by mediating phospholipid metabolism and generating key second messengers, such as inositol triphosphate and diacylglycerol, leading to intracellular Ca2+ mobilization and activation of kinases, such as protein kinases C. In pancreatic β-cells, PLCβ-mediated signaling activated by various factors, such as free fatty acids and neuronal and hormonal ligands, has been confirmed as being involved in the regulation of insulin secretion, and PLCβs have been regarded as essential mediators for augmenting insulin secretion. In this review, we describe the physiological function of PLCβs in the regulation of glucose-stimulated insulin secretion and discuss emerging data on GPCR/PLCβ signaling that is being developed as a target for the treatment of diabetes mellitus.
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Affiliation(s)
- Hyeon-Jeong Hwang
- School of Life Sciences, Ulsan National Institute of Science and Technology, Ulsan, Republic of Korea
| | - Hyun-Jun Jang
- School of Life Sciences, Ulsan National Institute of Science and Technology, Ulsan, Republic of Korea
| | - Lucio Cocco
- Cellular Signaling Laboratory, Department of Biomedical Sciences, University of Bologna, Via Irnerio, 48, I-40126, Bologna, Italy
| | - Pann-Ghill Suh
- School of Life Sciences, Ulsan National Institute of Science and Technology, Ulsan, Republic of Korea.
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Gupta R, Nguyen DC, Schaid MD, Lei X, Balamurugan AN, Wong GW, Kim JA, Koltes JE, Kimple ME, Bhatnagar S. Complement 1q-like-3 protein inhibits insulin secretion from pancreatic β-cells via the cell adhesion G protein-coupled receptor BAI3. J Biol Chem 2018; 293:18086-18098. [PMID: 30228187 DOI: 10.1074/jbc.ra118.005403] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2018] [Revised: 09/06/2018] [Indexed: 01/04/2023] Open
Abstract
Secreted proteins are important metabolic regulators in both healthy and disease states. Here, we sought to investigate the mechanism by which the secreted protein complement 1q-like-3 (C1ql3) regulates insulin secretion from pancreatic β-cells, a key process affecting whole-body glucose metabolism. We found that C1ql3 predominantly inhibits exendin-4- and cAMP-stimulated insulin secretion from mouse and human islets. However, to a lesser extent, C1ql3 also reduced insulin secretion in response to KCl, the potassium channel blocker tolbutamide, and high glucose. Strikingly, C1ql3 did not affect insulin secretion stimulated by fatty acids, amino acids, or mitochondrial metabolites, either at low or submaximal glucose concentrations. Additionally, C1ql3 inhibited glucose-stimulated cAMP levels, and insulin secretion stimulated by exchange protein directly activated by cAMP-2 and protein kinase A. These results suggest that C1ql3 inhibits insulin secretion primarily by regulating cAMP signaling. The cell adhesion G protein-coupled receptor, brain angiogenesis inhibitor-3 (BAI3), is a C1ql3 receptor and is expressed in β-cells and in mouse and human islets, but its function in β-cells remained unknown. We found that siRNA-mediated Bai3 knockdown in INS1(832/13) cells increased glucose-stimulated insulin secretion. Furthermore, incubating the soluble C1ql3-binding fragment of the BAI3 protein completely blocked the inhibitory effects of C1ql3 on insulin secretion in response to cAMP. This suggests that BAI3 mediates the inhibitory effects of C1ql3 on insulin secretion from pancreatic β-cells. These findings demonstrate a novel regulatory mechanism by which C1ql3/BAI3 signaling causes an impairment of insulin secretion from β-cells, possibly contributing to the progression of type 2 diabetes in obesity.
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Affiliation(s)
- Rajesh Gupta
- From the Department of Medicine, Division of Endocrinology, Diabetes, and Metabolism, and Comprehensive Diabetes Center, University of Alabama, Birmingham, Alabama 35294
| | - Dan C Nguyen
- From the Department of Medicine, Division of Endocrinology, Diabetes, and Metabolism, and Comprehensive Diabetes Center, University of Alabama, Birmingham, Alabama 35294
| | - Michael D Schaid
- the Interdisciplinary Graduate Program in Nutritional Sciences, University of Wisconsin-Madison, Madison, Wisconsin 53706,; the William S. Middleton Memorial Veterans Hospital, Research Service, Madison, Wisconsin 53705
| | - Xia Lei
- the Department of Physiology and Center for Metabolism and Obesity Research, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205
| | | | - G William Wong
- the Department of Physiology and Center for Metabolism and Obesity Research, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205
| | - Jeong-A Kim
- From the Department of Medicine, Division of Endocrinology, Diabetes, and Metabolism, and Comprehensive Diabetes Center, University of Alabama, Birmingham, Alabama 35294
| | - James E Koltes
- the Department of Animal Science, Iowa State University, Ames, Iowa 50011
| | - Michelle E Kimple
- the Interdisciplinary Graduate Program in Nutritional Sciences, University of Wisconsin-Madison, Madison, Wisconsin 53706,; the William S. Middleton Memorial Veterans Hospital, Research Service, Madison, Wisconsin 53705,; the Department of Medicine, Division of Endocrinology, Diabetes, and Metabolism, and the Department of Cell and Regenerative Biology, University of Wisconsin-Madison, Madison, Wisconsin 53705
| | - Sushant Bhatnagar
- From the Department of Medicine, Division of Endocrinology, Diabetes, and Metabolism, and Comprehensive Diabetes Center, University of Alabama, Birmingham, Alabama 35294,.
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Neelankal John A, Jiang FX. An overview of type 2 diabetes and importance of vitamin D3-vitamin D receptor interaction in pancreatic β-cells. J Diabetes Complications 2018; 32:429-443. [PMID: 29422234 DOI: 10.1016/j.jdiacomp.2017.12.002] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/10/2017] [Revised: 12/03/2017] [Accepted: 12/07/2017] [Indexed: 02/07/2023]
Abstract
One significant health issue that plagues contemporary society is that of Type 2 diabetes (T2D). This disease is characterised by higher-than-average blood glucose levels as a result of a combination of insulin resistance and insufficient insulin secretions from the β-cells of pancreatic islets of Langerhans. Previous developmental research into the pancreas has identified how early precursor genes of pancreatic β-cells, such as Cpal, Ngn3, NeuroD, Ptf1a, and cMyc, play an essential role in the differentiation of these cells. Furthermore, β-cell molecular characterization has also revealed the specific role of β-cell-markers, such as Glut2, MafA, Ins1, Ins2, and Pdx1 in insulin expression. The expression of these genes appears to be suppressed in the T2D β-cells, along with the reappearance of the early endocrine marker genes. Glucose transporters transport glucose into β-cells, thereby controlling insulin release during hyperglycaemia. This stimulates glycolysis through rises in intracellular calcium (a process enhanced by vitamin D) (Norman et al., 1980), activating 2 of 4 proteinases. The rise in calcium activates half of pancreatic β-cell proinsulinases, thus releasing free insulin from granules. The synthesis of ATP from glucose by glycolysis, Krebs cycle and oxidative phosphorylation plays a role in insulin release. Some studies have found that the β-cells contain high levels of the vitamin D receptor; however, the role that this plays in maintaining the maturity of the β-cells remains unknown. Further research is required to develop a more in-depth understanding of the role VDR plays in β-cell function and the processes by which the beta cell function is preserved.
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Affiliation(s)
- Abraham Neelankal John
- Harry Perkins Institute of Medical Research, Centre for Medical Research, University of Western Australia, Nedlands, Western Australia, Australia; School of Medicine and Pharmacology, University of Western Australia, Carwley, Western Australia, Australia
| | - Fang-Xu Jiang
- Harry Perkins Institute of Medical Research, Centre for Medical Research, University of Western Australia, Nedlands, Western Australia, Australia; School of Medicine and Pharmacology, University of Western Australia, Carwley, Western Australia, Australia.
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Gutierrez BA, Chavez MA, Rodarte AI, Ramos MA, Dominguez A, Petrova Y, Davalos AJ, Costa RM, Elizondo R, Tuvim MJ, Dickey BF, Burns AR, Heidelberger R, Adachi R. Munc18-2, but not Munc18-1 or Munc18-3, controls compound and single-vesicle-regulated exocytosis in mast cells. J Biol Chem 2018; 293:7148-7159. [PMID: 29599294 DOI: 10.1074/jbc.ra118.002455] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2018] [Revised: 03/20/2018] [Indexed: 11/06/2022] Open
Abstract
Mast cells (MCs) play pivotal roles in many inflammatory conditions including infections, anaphylaxis, and asthma. MCs store immunoregulatory compounds in their large cytoplasmic granules and, upon stimulation, secrete them via regulated exocytosis. Exocytosis in many cells requires the participation of Munc18 proteins (also known as syntaxin-binding proteins), and we found that mature MCs express all three mammalian isoforms: Munc18-1, -2, and -3. To study their functions in MC effector responses and test the role of MC degranulation in anaphylaxis, we used conditional knockout (cKO) mice in which each Munc18 protein was deleted exclusively in MCs. Using recordings of plasma membrane capacitance for high-resolution analysis of exocytosis in individual MCs, we observed an almost complete absence of exocytosis in Munc18-2-deficient MCs but intact exocytosis in MCs lacking Munc18-1 or Munc18-3. Stereological analysis of EM images of stimulated MCs revealed that the deletion of Munc18-2 also abolishes the homotypic membrane fusion required for compound exocytosis. We confirmed the severe defect in regulated exocytosis in the absence of Munc18-2 by measuring the secretion of mediators stored in MC granules. Munc18-2 cKO mice had normal morphology, development, and distribution of their MCs, indicating that Munc18-2 is not essential for the migration, retention, and maturation of MC-committed progenitors. Despite that, we found that Munc18-2 cKO mice were significantly protected from anaphylaxis. In conclusion, MC-regulated exocytosis is required for the anaphylactic response, and Munc18-2 is the sole Munc18 isoform that mediates membrane fusion during MC degranulation.
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Affiliation(s)
- Berenice A Gutierrez
- Department of Pulmonary Medicine, University of Texas M. D. Anderson Cancer Center, Houston, Texas 77030; Escuela de Ingeniería y Ciencias, Tecnologico de Monterrey, Monterrey NL 64849 México
| | - Miguel A Chavez
- Department of Pulmonary Medicine, University of Texas M. D. Anderson Cancer Center, Houston, Texas 77030; Escuela de Medicina y Ciencias de la Salud, Tecnologico de Monterrey, Monterrey NL 64710 México
| | - Alejandro I Rodarte
- Department of Pulmonary Medicine, University of Texas M. D. Anderson Cancer Center, Houston, Texas 77030; Escuela de Medicina y Ciencias de la Salud, Tecnologico de Monterrey, Monterrey NL 64710 México
| | - Marco A Ramos
- Department of Pulmonary Medicine, University of Texas M. D. Anderson Cancer Center, Houston, Texas 77030
| | - Andrea Dominguez
- Escuela de Medicina y Ciencias de la Salud, Tecnologico de Monterrey, Monterrey NL 64710 México
| | - Youlia Petrova
- Department of Pulmonary Medicine, University of Texas M. D. Anderson Cancer Center, Houston, Texas 77030
| | - Alfredo J Davalos
- Department of Pulmonary Medicine, University of Texas M. D. Anderson Cancer Center, Houston, Texas 77030
| | - Renan M Costa
- Graduate School of Biomedical Sciences, Houston, Texas 77030
| | - Ramon Elizondo
- Escuela de Medicina y Ciencias de la Salud, Tecnologico de Monterrey, Monterrey NL 64710 México
| | - Michael J Tuvim
- Department of Pulmonary Medicine, University of Texas M. D. Anderson Cancer Center, Houston, Texas 77030
| | - Burton F Dickey
- Department of Pulmonary Medicine, University of Texas M. D. Anderson Cancer Center, Houston, Texas 77030
| | - Alan R Burns
- College of Optometry, University of Houston, Houston, Texas 77204
| | - Ruth Heidelberger
- Department of Neurobiology and Anatomy, McGovern Medical School, University of Texas Health Science Center, Houston, Texas 77030
| | - Roberto Adachi
- Department of Pulmonary Medicine, University of Texas M. D. Anderson Cancer Center, Houston, Texas 77030.
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Munc18a clusters SNARE-bearing liposomes prior to trans-SNARE zippering. Biochem J 2017; 474:3339-3354. [PMID: 28827281 DOI: 10.1042/bcj20170494] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2017] [Revised: 08/16/2017] [Accepted: 08/17/2017] [Indexed: 12/16/2022]
Abstract
Sec1-Munc18 (SM) proteins co-operate with SNAREs {SNAP [soluble NSF (N-ethylmaleimide-sensitive factor) attachment protein] receptors} to mediate membrane fusion in eukaryotic cells. Studies of Munc18a/Munc18-1/Stxbp1 in neurotransmission suggest that SM proteins accelerate fusion kinetics primarily by activating the partially zippered trans-SNARE complex. However, accumulating evidence has argued for additional roles for SM proteins in earlier steps in the fusion cascade. Here, we investigate the function of Munc18a in reconstituted exocytic reactions mediated by neuronal and non-neuronal SNAREs. We show that Munc18a plays a direct role in promoting proteoliposome clustering, underlying vesicle docking during exocytosis. In the three different fusion reactions examined, Munc18a-dependent clustering requires an intact N-terminal peptide (N-peptide) motif in syntaxin that mediates the binary interaction between syntaxin and Munc18a. Importantly, clustering is preserved under inhibitory conditions that abolish both trans-SNARE complex formation and lipid mixing, indicating that Munc18a promotes membrane clustering in a step that is independent of trans-SNARE zippering and activation.
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RABIF/MSS4 is a Rab-stabilizing holdase chaperone required for GLUT4 exocytosis. Proc Natl Acad Sci U S A 2017; 114:E8224-E8233. [PMID: 28894007 DOI: 10.1073/pnas.1712176114] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Rab GTPases are switched from their GDP-bound inactive conformation to a GTP-bound active state by guanine nucleotide exchange factors (GEFs). The first putative GEFs isolated for Rabs are RABIF (Rab-interacting factor)/MSS4 (mammalian suppressor of Sec4) and its yeast homolog DSS4 (dominant suppressor of Sec4). However, the biological function and molecular mechanism of these molecules remained unclear. In a genome-wide CRISPR genetic screen, we isolated RABIF as a positive regulator of exocytosis. Knockout of RABIF severely impaired insulin-stimulated GLUT4 exocytosis in adipocytes. Unexpectedly, we discovered that RABIF does not function as a GEF, as previously assumed. Instead, RABIF promotes the stability of Rab10, a key Rab in GLUT4 exocytosis. In the absence of RABIF, Rab10 can be efficiently synthesized but is rapidly degraded by the proteasome, leading to exocytosis defects. Strikingly, restoration of Rab10 expression rescues exocytosis defects, bypassing the requirement for RABIF. These findings reveal a crucial role of RABIF in vesicle transport and establish RABIF as a Rab-stabilizing holdase chaperone, a previously unrecognized mode of Rab regulation independent of its GDP-releasing activity. Besides Rab10, RABIF also regulates the stability of two other Rab GTPases, Rab8 and Rab13, suggesting that the requirement of holdase chaperones is likely a general feature of Rab GTPases.
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Brasher MI, Martynowicz DM, Grafinger OR, Hucik A, Shanks-Skinner E, Uniacke J, Coppolino MG. Interaction of Munc18c and syntaxin4 facilitates invadopodium formation and extracellular matrix invasion of tumor cells. J Biol Chem 2017; 292:16199-16210. [PMID: 28798239 DOI: 10.1074/jbc.m117.807438] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2017] [Revised: 08/08/2017] [Indexed: 12/17/2022] Open
Abstract
Tumor cell invasion involves targeted localization of proteins required for interactions with the extracellular matrix and for proteolysis. The localization of many proteins during these cell-extracellular matrix interactions relies on membrane trafficking mediated in part by SNAREs. The SNARE protein syntaxin4 (Stx4) is involved in the formation of invasive structures called invadopodia; however, it is unclear how Stx4 function is regulated during tumor cell invasion. Munc18c is known to regulate Stx4 activity, and here we show that Munc18c is required for Stx4-mediated invadopodium formation and cell invasion. Biochemical and microscopic analyses revealed a physical association between Munc18c and Stx4, which was enhanced during invadopodium formation, and that a reduction in Munc18c expression decreases invadopodium formation. We also found that an N-terminal Stx4-derived peptide associates with Munc18c and inhibits endogenous interactions of Stx4 with synaptosome-associated protein 23 (SNAP23) and vesicle-associated membrane protein 2 (VAMP2). Furthermore, expression of the Stx4 N-terminal peptide decreased invadopodium formation and cell invasion in vitro Of note, cells expressing the Stx4 N-terminal peptide exhibited impaired trafficking of membrane type 1 matrix metalloproteinase (MT1-MMP) and EGF receptor (EGFR) to the cell surface during invadopodium formation. Our findings implicate Munc18c as a regulator of Stx4-mediated trafficking of MT1-MMP and EGFR, advancing our understanding of the role of SNARE function in the localization of proteins that drive tumor cell invasion.
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Affiliation(s)
- Megan I Brasher
- From the Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario N1G 2W1, Canada
| | - David M Martynowicz
- From the Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario N1G 2W1, Canada
| | - Olivia R Grafinger
- From the Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario N1G 2W1, Canada
| | - Andrea Hucik
- From the Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario N1G 2W1, Canada
| | - Emma Shanks-Skinner
- From the Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario N1G 2W1, Canada
| | - James Uniacke
- From the Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario N1G 2W1, Canada
| | - Marc G Coppolino
- From the Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario N1G 2W1, Canada
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Samad MB, Mohsin MNAB, Razu BA, Hossain MT, Mahzabeen S, Unnoor N, Muna IA, Akhter F, Kabir AU, Hannan JMA. [6]-Gingerol, from Zingiber officinale, potentiates GLP-1 mediated glucose-stimulated insulin secretion pathway in pancreatic β-cells and increases RAB8/RAB10-regulated membrane presentation of GLUT4 transporters in skeletal muscle to improve hyperglycemia in Lepr db/db type 2 diabetic mice. BMC COMPLEMENTARY AND ALTERNATIVE MEDICINE 2017; 17:395. [PMID: 28793909 PMCID: PMC5550996 DOI: 10.1186/s12906-017-1903-0] [Citation(s) in RCA: 56] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/09/2017] [Accepted: 08/02/2017] [Indexed: 12/19/2022]
Abstract
BACKGROUND [6]-Gingerol, a major component of Zingiber officinale, was previously reported to ameliorate hyperglycemia in type 2 diabetic mice. Endocrine signaling is involved in insulin secretion and is perturbed in db/db Type-2 diabetic mice. [6]-Gingerol was reported to restore the disrupted endocrine signaling in rodents. In this current study on Leprdb/db diabetic mice, we investigated the involvement of endocrine pathway in the insulin secretagogue activity of [6]-Gingerol and the mechanism(s) through which [6]-Gingerol ameliorates hyperglycemia. METHODS Leprdb/db type 2 diabetic mice were orally administered a daily dose of [6]-Gingerol (200 mg/kg) for 28 days. We measured the plasma levels of different endocrine hormones in fasting and fed conditions. GLP-1 levels were modulated using pharmacological approaches, and cAMP/PKA pathway for insulin secretion was assessed by qRT-PCR and ELISA in isolated pancreatic islets. Total skeletal muscle and its membrane fractions were used to measure glycogen synthase 1 level and Glut4 expression and protein levels. RESULTS 4-weeks treatment of [6]-Gingerol dramatically increased glucose-stimulated insulin secretion and improved glucose tolerance. Plasma GLP-1 was found to be significantly elevated in the treated mice. Pharmacological intervention of GLP-1 levels regulated the effect of [6]-Gingerol on insulin secretion. Mechanistically, [6]-Gingerol treatment upregulated and activated cAMP, PKA, and CREB in the pancreatic islets, which are critical components of GLP-1-mediated insulin secretion pathway. [6]-Gingerol upregulated both Rab27a GTPase and its effector protein Slp4-a expression in isolated islets, which regulates the exocytosis of insulin-containing dense-core granules. [6]-Gingerol treatment improved skeletal glycogen storage by increased glycogen synthase 1 activity. Additionally, GLUT4 transporters were highly abundant in the membrane of the skeletal myocytes, which could be explained by the increased expression of Rab8 and Rab10 GTPases that are responsible for GLUT4 vesicle fusion to the membrane. CONCLUSIONS Collectively, our study reports that GLP-1 mediates the insulinotropic activity of [6]-Gingerol, and [6]-Gingerol treatment facilitates glucose disposal in skeletal muscles through increased activity of glycogen synthase 1 and enhanced cell surface presentation of GLUT4 transporters.
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Affiliation(s)
- Mehdi Bin Samad
- Department of Pharmaceutical Sciences, University of Nebraska Medical Center, Omaha, NE USA
- Department of Pharmaceutical Sciences, North South University, Dhaka, Bangladesh
| | | | - Bodiul Alam Razu
- Department of Pharmaceutical Sciences, North South University, Dhaka, Bangladesh
| | | | - Sinayat Mahzabeen
- Department of Pharmaceutical Sciences, North South University, Dhaka, Bangladesh
- Department of Pharmacy, BRAC University, Dhaka, Bangladesh
| | - Naziat Unnoor
- Department of Pharmaceutical Sciences, North South University, Dhaka, Bangladesh
| | - Ishrat Aklima Muna
- Department of Pharmaceutical Sciences, North South University, Dhaka, Bangladesh
- Seoul National University, Seoul, South Korea
| | - Farjana Akhter
- Department of Pharmaceutical Sciences, North South University, Dhaka, Bangladesh
| | - Ashraf Ul Kabir
- Department of Pharmaceutical Sciences, North South University, Dhaka, Bangladesh
- Washington University School of Medicine in St. Louis, St. Louis, MO USA
| | - J. M. A. Hannan
- Department of Pharmaceutical Sciences, North South University, Dhaka, Bangladesh
- Department of Pharmacy, East West University, Dhaka, Bangladesh
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Spessott WA, Sanmillan ML, Kulkarni VV, McCormick ME, Giraudo CG. Syntaxin 4 mediates endosome recycling for lytic granule exocytosis in cytotoxic T-lymphocytes. Traffic 2017; 18:442-452. [PMID: 28471021 PMCID: PMC5513838 DOI: 10.1111/tra.12490] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2016] [Revised: 04/30/2017] [Accepted: 05/01/2017] [Indexed: 12/15/2022]
Abstract
Adaptive and innate immunity utilize the perforin-killing pathway to eliminate virus-infected or cancer cells. Cytotoxic T-lymphocytes (CTLs) and natural killer cells mediate this process by releasing toxic proteins at the contact area with target cells known as immunological synapse (IS). Formation of a stable IS and exocytosis of toxic proteins requires persistent fusion of Rab11a recycling endosomes with the plasma membrane (PM) that may assure the delivery of key effector proteins. Despite the importance of the recycling endosomal compartment, the membrane fusion proteins that control this process at the IS remain elusive. Here, by performing knockdown experiments we found that syntaxin 4 (STX4) is necessary for cytotoxic activity and CD107a degranulation against target cells in a similar fashion to syntaxin 11, which is involved in lytic granule (LG) exocytosis and immunodeficiency when it is mutated. Using total internal reflection fluorescent microscopy we identified that STX4 mediates fusion of EGFP-Rab11a vesicles at the IS. Immunoprecipitation experiments in lysates of activated CTLs indicate that endogenous STX4 may drive this fusion step by interacting with cognate proteins: Munc18-3/SNAP23/VAMP7 and/or VAMP8. These results reveal the role of STX4 in mediating fusion of Rab11a endosomes upstream of lytic granules (LGs) exocytosis and further demonstrate the importance of this pathway in controlling CTL-mediated cytotoxicity.
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Affiliation(s)
- Waldo A. Spessott
- Department of Pathology and Laboratory Medicine, University of Pennsylvania – The Children’s Hospital of Philadelphia - 3615 Civic Center Blvd, Philadelphia PA, 19104
| | - Maria L. Sanmillan
- Department of Pathology and Laboratory Medicine, University of Pennsylvania – The Children’s Hospital of Philadelphia - 3615 Civic Center Blvd, Philadelphia PA, 19104
| | - Vineet V. Kulkarni
- Department of Pathology and Laboratory Medicine, University of Pennsylvania – The Children’s Hospital of Philadelphia - 3615 Civic Center Blvd, Philadelphia PA, 19104
- Biomedical Graduate Studies- University of Pennsylvania
| | - Margaret E. McCormick
- Department of Pathology and Laboratory Medicine, University of Pennsylvania – The Children’s Hospital of Philadelphia - 3615 Civic Center Blvd, Philadelphia PA, 19104
| | - Claudio G. Giraudo
- Department of Pathology and Laboratory Medicine, University of Pennsylvania – The Children’s Hospital of Philadelphia - 3615 Civic Center Blvd, Philadelphia PA, 19104
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Kawai S, Michikami I, Kitagaki J, Hata K, Kiyonari H, Abe T, Amano A, Wakisaka S. Syntaxin 4a Regulates Matrix Vesicle-Mediated Bone Matrix Production by Osteoblasts. J Bone Miner Res 2017; 32:440-448. [PMID: 27933643 DOI: 10.1002/jbmr.3056] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/29/2016] [Revised: 11/23/2016] [Accepted: 12/03/2013] [Indexed: 12/21/2022]
Abstract
Osteoblasts secrete matrix vesicles and proteins to bone surfaces, but the molecular mechanisms of this secretion system remain unclear. The present findings reveal the roles of important genes in osteoblasts involved in regulation of extracellular matrix secretion. We especially focused on "soluble N-ethylmaleimide-sensitive factor (NSF) attachment protein receptor" (SNARE) genes and identified notable Syntaxin 4a (Stx4a) expression on the basolateral side of the plasma membrane of osteoblasts. Furthermore, Stx4a overexpression was found to increase mineralization by osteoblastic cells, whereas Stx4a knockdown reduced levels of mineralization. Also, BMP-4 and IGF-1 induced the localization of Stx4a to the basolateral side of the cells. To examine the function of Stx4a in osteoblasts, we generated osteoblast-specific Stx4a conditional knockout mice, which demonstrated an osteopenic phenotype due to reduced matrix secretion. Bone mineral density, shown by peripheral quantitative computed tomography (pQCT), was reduced in the femur metaphyseal and diaphyseal regions of Stx4a osteoblast-specific deficient mice, whereas bone parameters, shown by micro-computed tomography (μCT) and bone histomorphometric analysis, were also decreased in trabecular bone. In addition, primary calvarial cells from those mice showed decreased mineralization and lower secretion of matrix vesicles. Our findings indicate that Stx4a plays a critical role in bone matrix production by osteoblasts. © 2016 American Society for Bone and Mineral Research.
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Affiliation(s)
- Shinji Kawai
- Challenge to Intractable Oral Diseases, Center for Frontier Oral Science, Osaka University Graduate School of Dentistry, Osaka, Japan
| | - Ikumi Michikami
- Challenge to Intractable Oral Diseases, Center for Frontier Oral Science, Osaka University Graduate School of Dentistry, Osaka, Japan
| | - Jirouta Kitagaki
- Challenge to Intractable Oral Diseases, Center for Frontier Oral Science, Osaka University Graduate School of Dentistry, Osaka, Japan
| | - Kenji Hata
- Department of Molecular and Cellular Biochemistry, Osaka University Graduate School of Dentistry, Osaka, Japan
| | - Hiroshi Kiyonari
- Laboratory for Animal Resources and Genetic Engineering, RIKEN Center for Developmental Biology, Hyogo, Japan
| | - Takaya Abe
- Laboratory for Animal Resources and Genetic Engineering, RIKEN Center for Developmental Biology, Hyogo, Japan
| | - Atsuo Amano
- Department of Preventive Dentistry, Osaka University Graduate School of Dentistry, Osaka, Japan
| | - Satoshi Wakisaka
- Challenge to Intractable Oral Diseases, Center for Frontier Oral Science, Osaka University Graduate School of Dentistry, Osaka, Japan.,Department of Oral Anatomy and Developmental Biology, Osaka University Graduate School of Dentistry, Osaka, Japan
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40
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Muhammad SA, Raza W, Nguyen T, Bai B, Wu X, Chen J. Cellular Signaling Pathways in Insulin Resistance-Systems Biology Analyses of Microarray Dataset Reveals New Drug Target Gene Signatures of Type 2 Diabetes Mellitus. Front Physiol 2017; 8:13. [PMID: 28179884 PMCID: PMC5264126 DOI: 10.3389/fphys.2017.00013] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2016] [Accepted: 01/09/2017] [Indexed: 01/09/2023] Open
Abstract
Purpose: Type 2 diabetes mellitus (T2DM) is a chronic and metabolic disorder affecting large set of population of the world. To widen the scope of understanding of genetic causes of this disease, we performed interactive and toxicogenomic based systems biology study to find potential T2DM related genes after cDNA differential analysis. Methods: From the list of 50-differential expressed genes (p < 0.05), we found 9-T2DM related genes using extensive data mapping. In our constructed gene-network, T2DM-related differentially expressed seeder genes (9-genes) are found to interact with functionally related gene signatures (31-genes). The genetic interaction network of both T2DM-associated seeder as well as signature genes generally relates well with the disease condition based on toxicogenomic and data curation. Results: These networks showed significant enrichment of insulin signaling, insulin secretion and other T2DM-related pathways including JAK-STAT, MAPK, TGF, Toll-like receptor, p53 and mTOR, adipocytokine, FOXO, PPAR, P13-AKT, and triglyceride metabolic pathways. We found some enriched pathways that are common in different conditions. We recognized 11-signaling pathways as a connecting link between gene signatures in insulin resistance and T2DM. Notably, in the drug-gene network, the interacting genes showed significant overlap with 13-FDA approved and few non-approved drugs. This study demonstrates the value of systems genetics for identifying 18 potential genes associated with T2DM that are probable drug targets. Conclusions: This integrative and network based approaches for finding variants in genomic data expect to accelerate identification of new drug target molecules for different diseases and can speed up drug discovery outcomes.
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Affiliation(s)
- Syed Aun Muhammad
- Institute of Molecular Biology and Biotechnology, Bahauddin Zakariya UniversityMultan, Pakistan; Institute of Biopharmaceutical Informatics and Technologies, Wenzhou Medical UniversityWenzhou, China; Wenzhou Medical University, 1st Affiliate Hospital WenzhouWenzhou, China
| | - Waseem Raza
- Institute of Molecular Biology and Biotechnology, Bahauddin Zakariya University Multan, Pakistan
| | - Thanh Nguyen
- Institute of Biopharmaceutical Informatics and Technologies, Wenzhou Medical UniversityWenzhou, China; Wenzhou Medical University, 1st Affiliate Hospital WenzhouWenzhou, China; Department of Computer and Information Science, Purdue UniversityIndianapolis, IN, USA
| | - Baogang Bai
- Institute of Biopharmaceutical Informatics and Technologies, Wenzhou Medical University Wenzhou, China
| | - Xiaogang Wu
- Institute for Systems Biology Seattle, WA, USA
| | - Jake Chen
- Institute of Biopharmaceutical Informatics and Technologies, Wenzhou Medical UniversityWenzhou, China; Wenzhou Medical University, 1st Affiliate Hospital WenzhouWenzhou, China; Department of Computer and Information Science, Purdue UniversityIndianapolis, IN, USA; Indiana Center for Systems Biology and Personalized Medicine, Indiana University-Purdue UniversityIndianapolis, IN, USA; Informatics Institute, School of Medicine, The University of AlabamaBirmingham, AL, USA
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41
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Qin T, Liang T, Zhu D, Kang Y, Xie L, Dolai S, Sugita S, Takahashi N, Ostenson CG, Banks K, Gaisano HY. Munc18b Increases Insulin Granule Fusion, Restoring Deficient Insulin Secretion in Type-2 Diabetes Human and Goto-Kakizaki Rat Islets with Improvement in Glucose Homeostasis. EBioMedicine 2017; 16:262-274. [PMID: 28163042 PMCID: PMC5474508 DOI: 10.1016/j.ebiom.2017.01.030] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2016] [Revised: 01/09/2017] [Accepted: 01/20/2017] [Indexed: 01/22/2023] Open
Abstract
Reduced pancreatic islet levels of Munc18a/SNARE complex proteins have been postulated to contribute to the deficient glucose-stimulated insulin secretion (GSIS) in type-2 diabetes (T2D). Whereas much previous work has purported Munc18a/SNARE complex (Syntaxin-1A/VAMP-2/SNAP25) to be primarily involved in predocked secretory granule (SG) fusion, less is known about newcomer SGs that undergo minimal docking time at the plasma membrane before fusion. Newcomer SG fusion has been postulated to involve a distinct SM/SNARE complex (Munc18b/Syntaxin-3/VAMP8/SNAP25), whose levels we find also reduced in islets of T2D humans and T2D Goto-Kakizaki (GK) rats. Munc18b overexpression by adenovirus infection (Ad-Munc18b), by increasing assembly of Munc18b/SNARE complexes, mediated increased fusion of not only newcomer SGs but also predocked SGs in T2D human and GK rat islets, resulting in rescue of the deficient biphasic GSIS. Infusion of Ad-Munc18b into GK rat pancreas led to sustained improvement in glucose homeostasis. However, Munc18b overexpression in normal islets increased only newcomer SG fusion. Therefore, Munc18b could potentially be deployed in human T2D to rescue the deficient GSIS. Human T2D islet β-cells exhibit reduced fusion of predocked & newcomer secretory granules (SGs). Munc18b increases SNARE complexes involved in fusions of both newcomer & predocked SGs. Munc18b rescue of newcomer & predocked SGs increased biphasic secretion in human T2D β-cells. Munc18b rescue of T2D Goto-Kakizaki rat β-cell secretion improves glucose homeostasis.
Deficient insulin secretion from pancreatic islet β-cells in type-2 diabetes (T2D) is partly due to reduced expression of many proteins that assemble into specific complexes that mediate fusion of insulin secretory granules (SGs) with plasma membrane, termed exocytosis. We here show we can infuse a virus that contains the construct of one of the SG fusion proteins, Munc18b, into pancreatic ducts of T2D rats to reach the islets, which restored insulin secretion and improved glycemic control. Munc18b acts to promote the assembly of SG fusion complexes. This strategy could potentially be applied to treat human T2D by endoscopic infusion.
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Affiliation(s)
- Tairan Qin
- Department of Medicine, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Tao Liang
- Department of Medicine, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Dan Zhu
- Department of Medicine, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Youhou Kang
- Department of Medicine, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Li Xie
- Department of Medicine, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Subhankar Dolai
- Department of Medicine, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Shuzo Sugita
- Department of Physiology, University of Toronto, Toronto, ON M5S 1A8, Canada; Division of Fundamental Neurobiology, University Health Network, Toronto, ON M5T 2S8, Canada
| | - Noriko Takahashi
- Laboratory of Physiological Chemistry, Institute of Medicinal Chemistry, Hoshi University, Shinagawa, Tokyo 142-8501, Japan
| | - Claes-Goran Ostenson
- Department of Molecular Medicine and Surgery, Endocrinology and Diabetology Unit, Karolinska Institutet, Karolinska University Hospital, SE-171 76 Stockholm, Sweden
| | - Kate Banks
- Department of Physiology, University of Toronto, Toronto, ON M5S 1A8, Canada; Division of Comparative Medicine, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Herbert Y Gaisano
- Department of Medicine, University of Toronto, Toronto, ON M5S 1A8, Canada; Department of Physiology, University of Toronto, Toronto, ON M5S 1A8, Canada.
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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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Tunduguru R, Thurmond DC. Promoting Glucose Transporter-4 Vesicle Trafficking along Cytoskeletal Tracks: PAK-Ing Them Out. Front Endocrinol (Lausanne) 2017; 8:329. [PMID: 29209279 PMCID: PMC5701999 DOI: 10.3389/fendo.2017.00329] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/05/2017] [Accepted: 11/06/2017] [Indexed: 12/27/2022] Open
Abstract
Glucose is the principal cellular energy source in humans and maintenance of glucose homeostasis is critical for survival. Glucose uptake into peripheral skeletal muscle and adipose tissues requires the trafficking of vesicles containing glucose transporter-4 (GLUT4) from the intracellular storage compartments to the cell surface. Trafficking of GLUT4 storage vesicles is initiated via the canonical insulin signaling cascade in skeletal muscle and fat cells, as well as via exercise-induced contraction in muscle cells. Recent studies have elucidated steps in the signaling cascades that involve remodeling of the cytoskeleton, a process that underpins the mechanical movement of GLUT4 vesicles. This review is focused upon an alternate phosphoinositide-3 kinase-dependent pathway involving Ras-related C3 botulinum toxin substrate 1 signaling through the p21-activated kinase p21-activated kinase 1 and showcases related signaling events that co-regulate both the depolymerization and re-polymerization of filamentous actin. These new insights provide an enriched understanding into the process of glucose transport and yield potential new targets for interventions aimed to improve insulin sensitivity and remediate insulin resistance, pre-diabetes, and the progression to type 2 diabetes.
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Affiliation(s)
- Ragadeepthi Tunduguru
- Department of Molecular and Cellular Endocrinology, Diabetes and Metabolism Research Institute of City of Hope, Duarte, CA, United States
| | - Debbie C. Thurmond
- Department of Molecular and Cellular Endocrinology, Diabetes and Metabolism Research Institute of City of Hope, Duarte, CA, United States
- *Correspondence: Debbie C. Thurmond,
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44
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Beseni BK, Bagla VP, Njanje I, Matsebatlela TM, Mampuru L, Mokgotho MP. Antioxidant, Antiglycation, and Hypoglycaemic Effect of Seriphium plumosum Crude Plant Extracts. EVIDENCE-BASED COMPLEMENTARY AND ALTERNATIVE MEDICINE : ECAM 2017; 2017:6453567. [PMID: 29259646 PMCID: PMC5702973 DOI: 10.1155/2017/6453567] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/15/2017] [Accepted: 10/16/2017] [Indexed: 01/03/2023]
Abstract
Diabetes is a severely debilitating metabolic disorder characterised by chronic hyperglycaemia. Traditional medicinal plants provide an important avenue for the development of novel antidiabetic agents. The antidiabetic potential of the methanol, acetone, and hexane extracts of S. plumosum was assessed using different parameters. These included secondary metabolite quantification, hypoglycaemic, cytotoxic effects, and GLUT4 translocation augmentation on C2C12 cells. The methanol extract contained the highest amount of total phenolic and flavonoid compounds and showed enhanced antioxidant activity. The methanol extracts had the best DPPH scavenging (EC50 = 0.72 mg/ml) and ferric reducing powers (EC50 = 2.31 mg/ml). The hexane extract resulted in the highest glucose uptake activity of 35, 77% with respect to all other treatments after a 6-hour exposure period. Immunocytochemistry technique further revealed that the increased glucose utilisation may be due to increased membrane fused GLUT4 molecules in C2C12 cells. The hexane extract was also shown to upregulate the phosphorylation of p70 S6 kinase and Akt1/2. The study highlights a probable insulin-mimetic activity of the hexane extract via the augmentation of Akt1/2 phosphorylation which is involved in the GLUT4 translocation pathway. Furthermore, the study represents the first report on the cytotoxic effect, GLUT4 translocation, and glucose uptake potential of S. plumosum.
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Affiliation(s)
- Brian K. Beseni
- Department of Biochemistry, Microbiology and Biotechnology, University of Limpopo, Private Bag x1106, Sovenga 0727, South Africa
| | - Victor P. Bagla
- Department of Biochemistry, Microbiology and Biotechnology, University of Limpopo, Private Bag x1106, Sovenga 0727, South Africa
| | - Idris Njanje
- Department of Biochemistry, Microbiology and Biotechnology, University of Limpopo, Private Bag x1106, Sovenga 0727, South Africa
| | - Thabe M. Matsebatlela
- Department of Biochemistry, Microbiology and Biotechnology, University of Limpopo, Private Bag x1106, Sovenga 0727, South Africa
| | - Leseilane Mampuru
- Department of Biochemistry, Microbiology and Biotechnology, University of Limpopo, Private Bag x1106, Sovenga 0727, South Africa
| | - Matlou P. Mokgotho
- Department of Biochemistry, Microbiology and Biotechnology, University of Limpopo, Private Bag x1106, Sovenga 0727, South Africa
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45
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Liang T, Qin T, Xie L, Dolai S, Zhu D, Prentice KJ, Wheeler M, Kang Y, Osborne L, Gaisano HY. New Roles of Syntaxin-1A in Insulin Granule Exocytosis and Replenishment. J Biol Chem 2016; 292:2203-2216. [PMID: 28031464 DOI: 10.1074/jbc.m116.769885] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2016] [Indexed: 01/14/2023] Open
Abstract
In type-2 diabetes (T2D), severely reduced islet syntaxin-1A (Syn-1A) levels contribute to insulin secretory deficiency. We generated β-cell-specific Syn-1A-KO (Syn-1A-βKO) mice to mimic β-cell Syn-1A deficiency in T2D. Glucose tolerance tests showed that Syn-1A-βKO mice exhibited blood glucose elevation corresponding to reduced blood insulin levels. Perifusion of Syn-1A-βKO islets showed impaired first- and second-phase glucose-stimulated insulin secretion (GSIS) resulting from reduction in readily releasable pool and granule pool refilling. To unequivocally determine the β-cell exocytotic defects caused by Syn-1A deletion, EM and total internal reflection fluorescence microscopy showed that Syn-1A-KO β-cells had a severe reduction in the number of secretory granules (SGs) docked onto the plasma membrane (PM) at rest and reduced SG recruitment to the PM after glucose stimulation, the latter indicating defects in replenishment of releasable pools required to sustain second-phase GSIS. Whereas reduced predocked SG fusion accounted for reduced first-phase GSIS, selective reduction of exocytosis of short-dock (but not no-dock) newcomer SGs accounted for the reduced second-phase GSIS. These Syn-1A actions on newcomer SGs were partly mediated by Syn-1A interactions with newcomer SG VAMP8.
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Affiliation(s)
- Tao Liang
- From the Departments of Medicine.,Physiology, University of Toronto, Toronto, Ontario M5S 1A8, Canada
| | - Tairan Qin
- From the Departments of Medicine.,Physiology, University of Toronto, Toronto, Ontario M5S 1A8, Canada
| | - Li Xie
- From the Departments of Medicine.,Physiology, University of Toronto, Toronto, Ontario M5S 1A8, Canada
| | - Subhankar Dolai
- From the Departments of Medicine.,Physiology, University of Toronto, Toronto, Ontario M5S 1A8, Canada
| | - Dan Zhu
- From the Departments of Medicine.,Physiology, University of Toronto, Toronto, Ontario M5S 1A8, Canada
| | - Kacey J Prentice
- Physiology, University of Toronto, Toronto, Ontario M5S 1A8, Canada
| | - Michael Wheeler
- Physiology, University of Toronto, Toronto, Ontario M5S 1A8, Canada
| | - Youhou Kang
- From the Departments of Medicine.,Physiology, University of Toronto, Toronto, Ontario M5S 1A8, Canada
| | - Lucy Osborne
- From the Departments of Medicine.,Molecular Genetics, and
| | - Herbert Y Gaisano
- From the Departments of Medicine, .,Physiology, University of Toronto, Toronto, Ontario M5S 1A8, Canada
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Velasco M, Díaz-García CM, Larqué C, Hiriart M. Modulation of Ionic Channels and Insulin Secretion by Drugs and Hormones in Pancreatic Beta Cells. Mol Pharmacol 2016; 90:341-57. [PMID: 27436126 DOI: 10.1124/mol.116.103861] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2016] [Accepted: 07/18/2016] [Indexed: 12/11/2022] Open
Abstract
Pancreatic beta cells, unique cells that secrete insulin in response to an increase in glucose levels, play a significant role in glucose homeostasis. Glucose-stimulated insulin secretion (GSIS) in pancreatic beta cells has been extensively explored. In this mechanism, glucose enters the cells and subsequently the metabolic cycle. During this process, the ATP/ADP ratio increases, leading to ATP-sensitive potassium (KATP) channel closure, which initiates depolarization that is also dependent on the activity of TRP nonselective ion channels. Depolarization leads to the opening of voltage-gated Na(+) channels (Nav) and subsequently voltage-dependent Ca(2+) channels (Cav). The increase in intracellular Ca(2+) triggers the exocytosis of insulin-containing vesicles. Thus, electrical activity of pancreatic beta cells plays a central role in GSIS. Moreover, many growth factors, incretins, neurotransmitters, and hormones can modulate GSIS, and the channels that participate in GSIS are highly regulated. In this review, we focus on the principal ionic channels (KATP, Nav, and Cav channels) involved in GSIS and how classic and new proteins, hormones, and drugs regulate it. Moreover, we also discuss advances on how metabolic disorders such as metabolic syndrome and diabetes mellitus change channel activity leading to changes in insulin secretion.
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Affiliation(s)
- Myrian Velasco
- Department of Neurodevelopment and Physiology, Neuroscience Division, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Carlos Manlio Díaz-García
- Department of Neurodevelopment and Physiology, Neuroscience Division, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Carlos Larqué
- Department of Neurodevelopment and Physiology, Neuroscience Division, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Marcia Hiriart
- Department of Neurodevelopment and Physiology, Neuroscience Division, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Mexico City, Mexico
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47
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Liu J, Pang ZP. Glucagon-like peptide-1 drives energy metabolism on the synaptic highway. FEBS J 2016; 283:4413-4423. [DOI: 10.1111/febs.13785] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2016] [Revised: 06/04/2016] [Accepted: 06/16/2016] [Indexed: 01/17/2023]
Affiliation(s)
- Ji Liu
- Child Health Institute of New Jersey; Rutgers University Robert Wood Johnson Medical School; New Brunswick NJ USA
- Department of Neuroscience and Cell Biology; Rutgers University Robert Wood Johnson Medical School; New Brunswick NJ USA
| | - Zhiping P. Pang
- Child Health Institute of New Jersey; Rutgers University Robert Wood Johnson Medical School; New Brunswick NJ USA
- Department of Neuroscience and Cell Biology; Rutgers University Robert Wood Johnson Medical School; New Brunswick NJ USA
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Harris KP, Zhang YV, Piccioli ZD, Perrimon N, Littleton JT. The postsynaptic t-SNARE Syntaxin 4 controls traffic of Neuroligin 1 and Synaptotagmin 4 to regulate retrograde signaling. eLife 2016; 5. [PMID: 27223326 PMCID: PMC4880446 DOI: 10.7554/elife.13881] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2015] [Accepted: 04/25/2016] [Indexed: 12/14/2022] Open
Abstract
Postsynaptic cells can induce synaptic plasticity through the release of activity-dependent retrograde signals. We previously described a Ca(2+)-dependent retrograde signaling pathway mediated by postsynaptic Synaptotagmin 4 (Syt4). To identify proteins involved in postsynaptic exocytosis, we conducted a screen for candidates that disrupted trafficking of a pHluorin-tagged Syt4 at Drosophila neuromuscular junctions (NMJs). Here we characterize one candidate, the postsynaptic t-SNARE Syntaxin 4 (Syx4). Analysis of Syx4 mutants reveals that Syx4 mediates retrograde signaling, modulating the membrane levels of Syt4 and the transsynaptic adhesion protein Neuroligin 1 (Nlg1). Syx4-dependent trafficking regulates synaptic development, including controlling synaptic bouton number and the ability to bud new varicosities in response to acute neuronal stimulation. Genetic interaction experiments demonstrate Syx4, Syt4, and Nlg1 regulate synaptic growth and plasticity through both shared and parallel signaling pathways. Our findings suggest a conserved postsynaptic SNARE machinery controls multiple aspects of retrograde signaling and cargo trafficking within the postsynaptic compartment.
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Affiliation(s)
- Kathryn P Harris
- The Picower Institute for Learning and Memory, Massachusetts Institute of Technology, Cambridge, United States.,Department of Biology, Massachusetts Institute of Technology, Cambridge, United States.,Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, United States
| | - Yao V Zhang
- The Picower Institute for Learning and Memory, Massachusetts Institute of Technology, Cambridge, United States.,Department of Biology, Massachusetts Institute of Technology, Cambridge, United States.,Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, United States
| | - Zachary D Piccioli
- The Picower Institute for Learning and Memory, Massachusetts Institute of Technology, Cambridge, United States.,Department of Biology, Massachusetts Institute of Technology, Cambridge, United States.,Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, United States
| | - Norbert Perrimon
- Department of Genetics, Harvard Medical School, Boston, United States.,Howard Hughes Medical Institute, Harvard Medical School, Boston, United States
| | - J Troy Littleton
- The Picower Institute for Learning and Memory, Massachusetts Institute of Technology, Cambridge, United States.,Department of Biology, Massachusetts Institute of Technology, Cambridge, United States.,Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, United States
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49
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Talantikite M, Berenguer M, Gonzalez T, Alessi MC, Poggi M, Peiretti F, Govers R. The first intracellular loop of GLUT4 contains a retention motif. J Cell Sci 2016; 129:2273-84. [DOI: 10.1242/jcs.183525] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2015] [Accepted: 04/20/2016] [Indexed: 01/02/2023] Open
Abstract
Glucose transporter GLUT4 plays a major role in glucose homeostasis and is efficiently retained intracellularly in adipocytes and myocytes. To simplify the analysis of its retention, various intracellular GLUT4 domains were fused individually to reporter molecules. Of the four short cytoplasmic loops of GLUT4, only the first nine-residue-long loop conferred intracellular retention of truncated forms of the transferrin receptor and CD4 in adipocytes. In contrast, the same loop of GLUT1 was without effect. The reporter molecules to which the first loop of GLUT4 was fused localized, unlike GLUT4, to the TGN, possibly explaining why these molecules did not respond to insulin. The retention induced by the GLUT4 loop was specific to adipocytes as it did not induce retention in preadipocytes. Of the SQWLGRKRA sequence that constitutes this loop, mutation of either the tryptophan or lysine residue abrogated reporter retention. Mutation of these residues individually into alanines in the full-length GLUT4 molecule resulted in a decreased retention for GLUT4-W105A. We conclude that the first intracellular loop of GLUT4 contains retention motif WLGRK, in which Trp105 plays a prominent role.
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Affiliation(s)
- Maya Talantikite
- Inserm U1062, INRA1260, Aix Marseille University, Faculty of Medicine, Marseille F-13385, France
| | - Marion Berenguer
- Inserm U895, Mediterranean Research Center for Molecular Medicine (C3M), Nice, F-06204, France
| | - Teresa Gonzalez
- Inserm U1062, INRA1260, Aix Marseille University, Faculty of Medicine, Marseille F-13385, France
| | - Marie Christine Alessi
- Inserm U1062, INRA1260, Aix Marseille University, Faculty of Medicine, Marseille F-13385, France
| | - Marjorie Poggi
- Inserm U1062, INRA1260, Aix Marseille University, Faculty of Medicine, Marseille F-13385, France
| | - Franck Peiretti
- Inserm U1062, INRA1260, Aix Marseille University, Faculty of Medicine, Marseille F-13385, France
| | - Roland Govers
- Inserm U1062, INRA1260, Aix Marseille University, Faculty of Medicine, Marseille F-13385, France
- Inserm U895, Mediterranean Research Center for Molecular Medicine (C3M), Nice, F-06204, France
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50
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Grassi D, Plonka FB, Oksdath M, Guil AN, Sosa LJ, Quiroga S. Selected SNARE proteins are essential for the polarized membrane insertion of igf-1 receptor and the regulation of initial axonal outgrowth in neurons. Cell Discov 2015; 1:15023. [PMID: 27462422 PMCID: PMC4860833 DOI: 10.1038/celldisc.2015.23] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2015] [Accepted: 07/07/2015] [Indexed: 02/08/2023] Open
Abstract
The establishment of polarity necessitates initial axonal outgrowth and,
therefore, the addition of new membrane to the axon’s plasmalemma.
Axolemmal expansion occurs by exocytosis of plasmalemmal precursor vesicles
(PPVs) primarily at the neuronal growth cone. Little is known about the SNAREs
family proteins involved in the regulation of PPV fusion with the neuronal
plasmalemma at early stages of differentiation. We show here that five SNARE
proteins (VAMP2, VAMP4, VAMP7, Syntaxin6 and SNAP23) were expressed by
hippocampal pyramidal neurons before polarization. Expression silencing of three
of these proteins (VAMP4, Syntaxin6 and SNAP23) repressed axonal outgrowth and
the establishment of neuronal polarity, by inhibiting IGF-1 receptor exocytotic
polarized insertion, necessary for neuronal polarization. In addition,
stimulation with IGF-1 triggered the association of VAMP4, Syntaxin6 and SNAP23
to vesicular structures carrying the IGF-1 receptor and overexpression of a
negative dominant form of Syntaxin6 significantly inhibited exocytosis of IGF-1
receptor containing vesicles at the neuronal growth cone. Taken together, our
results indicated that VAMP4, Syntaxin6 and SNAP23 functions are essential for
regulation of PPV exocytosis and the polarized insertion of IGF-1 receptor and,
therefore, required for initial axonal elongation and the establishment of
neuronal polarity.
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Affiliation(s)
- Diego Grassi
- Departamento de Química Biológica-CIQUIBIC, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba-CONICET , Córdoba, Argentina
| | - Florentyna Bustos Plonka
- Departamento de Química Biológica-CIQUIBIC, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba-CONICET , Córdoba, Argentina
| | - Mariana Oksdath
- Departamento de Química Biológica-CIQUIBIC, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba-CONICET , Córdoba, Argentina
| | - Alvaro Nieto Guil
- Departamento de Química Biológica-CIQUIBIC, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba-CONICET , Córdoba, Argentina
| | - Lucas J Sosa
- Departamento de Química Biológica-CIQUIBIC, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba-CONICET , Córdoba, Argentina
| | - Santiago Quiroga
- Departamento de Química Biológica-CIQUIBIC, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba-CONICET , Córdoba, Argentina
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