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Li J, Huang X, An Y, Chen X, Chen Y, Xu M, Shan H, Zhang M. The role of snapin in regulation of brain homeostasis. Neural Regen Res 2024; 19:1696-1701. [PMID: 38103234 PMCID: PMC10960280 DOI: 10.4103/1673-5374.389364] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2023] [Revised: 09/15/2023] [Accepted: 10/08/2023] [Indexed: 12/18/2023] Open
Abstract
Brain homeostasis refers to the normal working state of the brain in a certain period, which is important for overall health and normal life activities. Currently, there is a lack of effective treatment methods for the adverse consequences caused by brain homeostasis imbalance. Snapin is a protein that assists in the formation of neuronal synapses and plays a crucial role in the normal growth and development of synapses. Recently, many researchers have reported the association between snapin and neurologic and psychiatric disorders, demonstrating that snapin can improve brain homeostasis. Clinical manifestations of brain disease often involve imbalances in brain homeostasis and may lead to neurological and behavioral sequelae. This article aims to explore the role of snapin in restoring brain homeostasis after injury or diseases, highlighting its significance in maintaining brain homeostasis and treating brain diseases. Additionally, it comprehensively discusses the implications of snapin in other extracerebral diseases such as diabetes and viral infections, with the objective of determining the clinical potential of snapin in maintaining brain homeostasis.
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Affiliation(s)
- Jiawen Li
- Shanghai Key Lab of Forensic Medicine, Key Lab of Forensic Science, Ministry of Justice, China (Academy of Forensic Science), Shanghai, China
- Institute of Forensic Sciences, Suzhou Medical College, Soochow University, Suzhou, Jiangsu Province, China
| | - Xinqi Huang
- Institute of Forensic Sciences, Suzhou Medical College, Soochow University, Suzhou, Jiangsu Province, China
| | - Yumei An
- Institute of Forensic Sciences, Suzhou Medical College, Soochow University, Suzhou, Jiangsu Province, China
| | - Xueshi Chen
- Institute of Forensic Sciences, Suzhou Medical College, Soochow University, Suzhou, Jiangsu Province, China
| | - Yiyang Chen
- Institute of Forensic Sciences, Suzhou Medical College, Soochow University, Suzhou, Jiangsu Province, China
| | - Mingyuan Xu
- Institute of Forensic Sciences, Suzhou Medical College, Soochow University, Suzhou, Jiangsu Province, China
| | - Haiyan Shan
- Department of Obstetrics and Gynecology, The Affiliated Suzhou Hospital of Nanjing Medical University, Suzhou, Jiangsu Province, China
| | - Mingyang Zhang
- Shanghai Key Lab of Forensic Medicine, Key Lab of Forensic Science, Ministry of Justice, China (Academy of Forensic Science), Shanghai, China
- Institute of Forensic Sciences, Suzhou Medical College, Soochow University, Suzhou, Jiangsu Province, China
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2
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Yu X, Benitez G, Wei PT, Krylova SV, Song Z, Liu L, Zhang M, Xiaoli AM, Wei H, Chen F, Sidoli S, Yang F, Shinoda K, Pessin JE, Feng D. Involution of brown adipose tissue through a Syntaxin 4 dependent pyroptosis pathway. Nat Commun 2024; 15:2856. [PMID: 38565851 PMCID: PMC10987578 DOI: 10.1038/s41467-024-46944-y] [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: 06/15/2023] [Accepted: 03/15/2024] [Indexed: 04/04/2024] Open
Abstract
Aging, chronic high-fat diet feeding, or housing at thermoneutrality induces brown adipose tissue (BAT) involution, a process characterized by reduction of BAT mass and function with increased lipid droplet size. Single nuclei RNA sequencing of aged mice identifies a specific brown adipocyte population of Ucp1-low cells that are pyroptotic and display a reduction in the longevity gene syntaxin 4 (Stx4a). Similar to aged brown adipocytes, Ucp1-STX4KO mice display loss of brown adipose tissue mass and thermogenic dysfunction concomitant with increased pyroptosis. Restoration of STX4 expression or suppression of pyroptosis activation protects against the decline in both mass and thermogenic activity in the aged and Ucp1-STX4KO mice. Mechanistically, STX4 deficiency reduces oxidative phosphorylation, glucose uptake, and glycolysis leading to reduced ATP levels, a known triggering signal for pyroptosis. Together, these data demonstrate an understanding of rapid brown adipocyte involution and that physiologic aging and thermogenic dysfunction result from pyroptotic signaling activation.
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Affiliation(s)
- Xiaofan Yu
- Department of Medicine, Albert Einstein College of Medicine, Bronx, NY, 10461, USA
- Fleischer Institute for Diabetes and Metabolism, Albert Einstein College of Medicine, Bronx, NY, 10461, USA
| | - Gabrielle Benitez
- Department of Medicine, Albert Einstein College of Medicine, Bronx, NY, 10461, USA
- Fleischer Institute for Diabetes and Metabolism, Albert Einstein College of Medicine, Bronx, NY, 10461, USA
| | - Peter Tszki Wei
- Department of Biological and Environmental Engineering, Cornell University, Ithaca, NY, 14853, USA
| | - Sofia V Krylova
- Department of Medicine, Albert Einstein College of Medicine, Bronx, NY, 10461, USA
- Fleischer Institute for Diabetes and Metabolism, Albert Einstein College of Medicine, Bronx, NY, 10461, USA
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, NY, 10461, USA
| | - Ziyi Song
- Guangxi Key Laboratory of Animal Breeding, Disease Control and Prevention, College of Animal Science and Technology, Guangxi University, Nanning, Guangxi, 530004, China
| | - Li Liu
- Department of Medicine, Albert Einstein College of Medicine, Bronx, NY, 10461, USA
- Fleischer Institute for Diabetes and Metabolism, Albert Einstein College of Medicine, Bronx, NY, 10461, USA
| | - Meifan Zhang
- Center for Advanced Biotechnology and Medicine, Rutgers University, Piscataway, NJ, 08854, USA
| | - Alus M Xiaoli
- Department of Medicine, Albert Einstein College of Medicine, Bronx, NY, 10461, USA
- Fleischer Institute for Diabetes and Metabolism, Albert Einstein College of Medicine, Bronx, NY, 10461, USA
- Department of Developmental and Molecular Biology, Albert Einstein College of Medicine, Bronx, NY, 10461, USA
| | - Henna Wei
- Department of Medicine, Albert Einstein College of Medicine, Bronx, NY, 10461, USA
| | - Fenfen Chen
- Department of Animal Science, College of Life Science, Southwest Forestry University, Kunming, Yunnan, 650244, China
| | - Simone Sidoli
- Department of Biochemistry, Albert Einstein College of Medicine, Bronx, NY, 10461, USA
| | - Fajun Yang
- Department of Medicine, Albert Einstein College of Medicine, Bronx, NY, 10461, USA
- Fleischer Institute for Diabetes and Metabolism, Albert Einstein College of Medicine, Bronx, NY, 10461, USA
- Department of Developmental and Molecular Biology, Albert Einstein College of Medicine, Bronx, NY, 10461, USA
| | - Kosaku Shinoda
- Department of Medicine, Albert Einstein College of Medicine, Bronx, NY, 10461, USA
- Fleischer Institute for Diabetes and Metabolism, Albert Einstein College of Medicine, Bronx, NY, 10461, USA
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, NY, 10461, USA
| | - Jeffrey E Pessin
- Department of Medicine, Albert Einstein College of Medicine, Bronx, NY, 10461, USA
- Fleischer Institute for Diabetes and Metabolism, Albert Einstein College of Medicine, Bronx, NY, 10461, USA
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, NY, 10461, USA
| | - Daorong Feng
- Department of Medicine, Albert Einstein College of Medicine, Bronx, NY, 10461, USA.
- Fleischer Institute for Diabetes and Metabolism, Albert Einstein College of Medicine, Bronx, NY, 10461, USA.
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3
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Warden CD, Wu X. Critical Differential Expression Assessment for Individual Bulk RNA-Seq Projects. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.02.10.579728. [PMID: 38405814 PMCID: PMC10888899 DOI: 10.1101/2024.02.10.579728] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/27/2024]
Abstract
Finding the right balance of quality and quantity can be important, and it is essential that project quality does not drop below the level where important main conclusions are missed or misstated. We use knock-out and over-expression studies as a simplification to test recovery of a known causal gene in RNA-Seq cell line experiments. When single-end RNA-Seq reads are aligned with STAR and quantified with htseq-count, we found potential value in testing the use of the Generalized Linear Model (GLM) implementation of edgeR with robust dispersion estimation more frequently for either single-variate or multi-variate 2-group comparisons (with the possibility of defining criteria less stringent than |fold-change| > 1.5 and FDR < 0.05). When considering a limited number of patient sample comparisons with larger sample size, there might be some decreased variability between methods (except for DESeq1). However, at the same time, the ranking of the gene identified using immunohistochemistry (for ER/PR/HER2 in breast cancer samples from The Cancer Genome Atlas) showed as possible shift in performance compared to the cell line comparisons, potentially highlighting utility for standard statistical tests and/or limma-based analysis with larger sample sizes. If this continues to be true in additional studies and comparisons, then that could be consistent with the possibility that it may be important to allocate time for potential methods troubleshooting for genomics projects. Analysis of public data presented in this study does not consider all experimental designs, and presentation of downstream analysis is limited. So, any estimate from this simplification would be an underestimation of the true need for some methods testing for every project. Additionally, this set of independent cell line experiments has a limitation in being able to determine the frequency of missing a highly important gene if the problem is rare (such as 10% or lower). For example, if there was an assumption that only one method can be tested for "initial" analysis, then it is not completely clear to the extent that using edgeR-robust might perform better than DESeq2 in the cell line experiments. Importantly, we do not wish to cause undue concern, and we believe that it should often be possible to define a gene expression differential expression workflow that is suitable for some purposes for many samples. Nevertheless, at the same time, we provide a variety of measures that we believe emphasize the need to critically assess every individual project and maximize confidence in published results.
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Affiliation(s)
- Charles D Warden
- Integrative Genomics Core, Department of Molecular and Cellular Biology, City of Hope National Medical Center, Duarte, CA
| | - Xiwei Wu
- Integrative Genomics Core, Department of Molecular and Cellular Biology, City of Hope National Medical Center, Duarte, CA
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Schrauwen I, Ghaffar A, Bharadwaj T, Shah K, Rehman S, Acharya A, Liaqat K, Lin NS, Everard JL, Khan A, Ahmed ZM, Ahmad W, Riazuddin S, Leal SM. Syntaxin 4 is essential for hearing in human and zebrafish. Hum Mol Genet 2023; 32:1184-1192. [PMID: 36355422 PMCID: PMC10026253 DOI: 10.1093/hmg/ddac257] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2022] [Revised: 08/22/2022] [Accepted: 11/11/2022] [Indexed: 11/12/2022] Open
Abstract
Congenital hearing impairment (HI) is a genetically highly heterogeneous disorder in which prompt recognition and intervention are crucial to optimize outcomes. In this study, we used exome sequencing to investigate a large consanguineous Pakistani family with eight affected individuals showing bilateral severe-to-profound HI. This identified a homozygous splice region variant in STX4 (c.232 + 6T>C), which causes exon skipping and a frameshift, that segregated with HI (two-point logarithm of odds (LOD) score = 5.9). STX4, a member of the syntaxin family, is a component of the SNARE machinery involved in several vesicle transport and recycling pathways. In silico analysis showed that murine orthologue Stx4a is highly and widespread expressed in the developing and adult inner ear. Immunofluorescent imaging revealed localization of STX4A in the cell body, cell membrane and stereocilia of inner and outer hair cells. Furthermore, a morpholino-based knockdown of stx4 in zebrafish showed an abnormal startle response, morphological and developmental defects, and a disrupted mechanotransduction function in neuromast hair cells measured via FM1-43 uptake. Our findings indicate that STX4 dysfunction leads to HI in humans and zebrafish and supports the evolutionary conserved role of STX4 in inner ear development and hair cell functioning.
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Affiliation(s)
- Isabelle Schrauwen
- Center for Statistical Genetics, Sergievsky Center, and the Department of Neurology, Columbia University Medical Center, New York, NY, USA
| | - Amama Ghaffar
- Department of Otorhinolaryngology - Head & Neck Surgery, School of Medicine University of Maryland, Baltimore, MD, USA
| | - Thashi Bharadwaj
- Center for Statistical Genetics, Sergievsky Center, and the Department of Neurology, Columbia University Medical Center, New York, NY, USA
| | - Khadim Shah
- Department of Biotechnology, COMSATS University Islamabad, Abbottabad Campus, Khyber Pakhtunkhwa, Pakistan
| | - Sakina Rehman
- Department of Otorhinolaryngology - Head & Neck Surgery, School of Medicine University of Maryland, Baltimore, MD, USA
| | - Anushree Acharya
- Center for Statistical Genetics, Sergievsky Center, and the Department of Neurology, Columbia University Medical Center, New York, NY, USA
| | - Khurram Liaqat
- Center for Statistical Genetics, Sergievsky Center, and the Department of Neurology, Columbia University Medical Center, New York, NY, USA
| | - Nicole S Lin
- Center for Statistical Genetics, Sergievsky Center, and the Department of Neurology, Columbia University Medical Center, New York, NY, USA
| | - Jenna L Everard
- Center for Statistical Genetics, Sergievsky Center, and the Department of Neurology, Columbia University Medical Center, New York, NY, USA
| | - Anwar Khan
- Department of Biochemistry, Hazara University Mansehra, Khyber Pakhtunkhwa, Pakistan
| | - Zubair M Ahmed
- Department of Otorhinolaryngology - Head & Neck Surgery, School of Medicine University of Maryland, Baltimore, MD, USA
| | - Wasim Ahmad
- Department of Biochemistry, Faculty of Biological Sciences, Quaid-i-Azam University Islamabad, Islamabad, Pakistan
| | - Saima Riazuddin
- Department of Otorhinolaryngology - Head & Neck Surgery, School of Medicine University of Maryland, Baltimore, MD, USA
| | - Suzanne M Leal
- Center for Statistical Genetics, Sergievsky Center, and the Department of Neurology, Columbia University Medical Center, New York, NY, USA
- Taub Institute for Alzheimer’s Disease and the Aging Brain, and the Department of Neurology, Columbia University Medical Center, New York, NY, USA
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Das UN. Syntaxin interacts with arachidonic acid to prevent diabetes mellitus. Lipids Health Dis 2022; 21:73. [PMID: 35982452 PMCID: PMC9389802 DOI: 10.1186/s12944-022-01681-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2022] [Accepted: 07/25/2022] [Indexed: 12/02/2022] Open
Abstract
Syntaxin regulates pancreatic β cell mass and participates in insulin secretion by regulating insulin exocytosis. In addition, syntaxin 4 reduces IFNγ and TNF-α signaling via NF-ĸB in islet β-cells that facilitates plasma glucose sensing and appropriate insulin secretion. Arachidonic acid (AA) has potent anti-inflammatory actions and prevents the cytotoxic actions of alloxan and streptozotocin (STZ) against pancreatic β cells and thus, prevents the development of type 1 diabetes mellitus (induced by alloxan and STZ) and by virtue of its anti-inflammatory actions protects against the development of type 2 diabetes mellitus (DM) induced by STZ in experimental animals that are models of type 1 and type 2 DM in humans. AA has been shown to interact with syntaxin and thus, potentiate exocytosis. AA enhances cell membrane fluidity, increases the expression of GLUT and insulin receptors, and brings about its anti-inflammatory actions at least in part by enhancing the formation of its metabolite lipoxin A4 (LXA4). Prostaglandin E2 (PGE2), the pro-inflammatory metabolite of AA, activates ventromedial hypothalamus (VMH) neurons of the hypothalamus and inhibits insulin secretion leading to reduced glucose tolerance and decreases insulin sensitivity in the skeletal muscle and liver. This adverse action of PGE2 on insulin release and action can be attributed to its (PGE2) pro-inflammatory action and inhibitory action on vagal tone (vagus nerve and its principal neurotransmitter acetylcholine has potent anti-inflammatory actions). High fat diet fed animals have hypothalamic inflammation due to chronic elevation of PGE2. Patients with type 2 DM show low plasma concentrations of AA and LXA4 and elevated levels of PGE2. Administration of AA enhances LXA4 formation without altering or reducing PGE2 levels and thus, tilts the balance more towards anti-inflammatory events. These results suggest that administration of AA is useful in the prevention and management of DM by enhancing the action of syntaxin, increasing cell membrane fluidity, and reducing VMH inflammation. Docosahexaenoic acid (DHA) has actions like AA: it increases cell membrane fluidity; has anti-inflammatory actions by enhancing the formation of its anti-inflammatory metabolites resolvins, protectins and maresins; interacts with syntaxin and enhance exocytosis in general and of insulin. But the DHA content of cell membrane is lower compared to AA and its content in brain is significant. Hence, it is likely DHA is important in neurotransmitters secretion and regulating hypothalamic inflammation. It is likely that a combination of AA and DHA can prevent DM.
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Affiliation(s)
- Undurti N Das
- UND Life Sciences, 2221 NW 5th St, Battle Ground, WA, 98604, USA. .,Department of Biotechnology, Indian Institute of Technology, IITH Road, Sangareddy, Kandi, Telangana, 502285, India.
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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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Wu Q, Dong J, Bai X, Jiang Y, Li J, Fan S, Cheng Y, Jiang G. Propionate ameliorates diabetes-induced neurological dysfunction through regulating the PI3K/Akt/eNOS signaling pathway. Eur J Pharmacol 2022; 925:174974. [PMID: 35490725 DOI: 10.1016/j.ejphar.2022.174974] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2021] [Revised: 03/31/2022] [Accepted: 04/19/2022] [Indexed: 11/24/2022]
Abstract
A large body of research has established diabetes-related cognitive deterioration, sometimes known as "diabetic encephalopathy". Current evidence supports that oxidative stress, neuronal apoptosis, and cerebral microcirculation weakness are associated with cognition deficits induced by diabetes. The present study explores the effect of propionate on neurological deficits, cerebral blood flow, and oxidative stress in diabetic mice. Propionate in different doses (37.5, 75 and 150 mg/kg) was orally administrated daily. Here, we show that propionate can markedly improve neurological function, which is correlated with its capabilities of stimulating nitrogen monoxide (NO) production, increasing cerebral microcirculation, suppressing oxidative stress, and reducing neuron loss in the hippocampus. In addition, the results of Western Blotting indicated that the brain-protective function of propionate in streptozocin (STZ)-induced type 1 diabetes mellitus (T1DM) mice is related to phosphoinositide 3-kinase (PI3K)/serine-threonine protein kinase (Akt)/endothelial nitrogen monoxide synthase (eNOS) signaling pathway. In a diabetic mouse model, propionate reduces cerebral microcirculation, hippocampus apoptosis, and neurological impairment. Thus, propionate, now employed as a food preservative, may also help slow diabetes-induced cognitive loss.
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Affiliation(s)
- Qin Wu
- Zhejiang University-University of Edinburgh Institute, Zhejiang University, Haining, Zhejiang, PR China
| | - Jiajun Dong
- Zhejiang University-University of Edinburgh Institute, Zhejiang University, Haining, Zhejiang, PR China
| | - Xinying Bai
- Key Laboratory of Combinatorial Biosynthesis and Drug Discovery, Ministry of Education, Wuhan University School of Pharmaceutical Sciences, Wuhan University, Wuhan, Hubei, PR China
| | - Yuan Jiang
- Key Laboratory of Combinatorial Biosynthesis and Drug Discovery, Ministry of Education, Wuhan University School of Pharmaceutical Sciences, Wuhan University, Wuhan, Hubei, PR China
| | - Jinjin Li
- Key Laboratory of Combinatorial Biosynthesis and Drug Discovery, Ministry of Education, Wuhan University School of Pharmaceutical Sciences, Wuhan University, Wuhan, Hubei, PR China
| | - Shiqi Fan
- Key Laboratory of Combinatorial Biosynthesis and Drug Discovery, Ministry of Education, Wuhan University School of Pharmaceutical Sciences, Wuhan University, Wuhan, Hubei, PR China
| | - Yahong Cheng
- Key Laboratory of Combinatorial Biosynthesis and Drug Discovery, Ministry of Education, Wuhan University School of Pharmaceutical Sciences, Wuhan University, Wuhan, Hubei, PR China.
| | - Gaofeng Jiang
- Center for Translational Medicine, Tianyou Hospital, Wuhan University of Science and Technology, Wuhan, Hubei, PR China.
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Merz KE, Hwang J, Zhou C, Veluthakal R, McCown EM, Hamilton A, Oh E, Dai W, Fueger PT, Jiang L, Huss JM, Thurmond DC. Enrichment of the exocytosis protein STX4 in skeletal muscle remediates peripheral insulin resistance and alters mitochondrial dynamics via Drp1. Nat Commun 2022; 13:424. [PMID: 35058456 PMCID: PMC8776765 DOI: 10.1038/s41467-022-28061-w] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2019] [Accepted: 01/05/2022] [Indexed: 12/15/2022] Open
Abstract
Mitochondrial dysfunction is implicated in skeletal muscle insulin resistance. Syntaxin 4 (STX4) levels are reduced in human diabetic skeletal muscle, and global transgenic enrichment of STX4 expression improves insulin sensitivity in mice. Here, we show that transgenic skeletal muscle-specific STX4 enrichment (skmSTX4tg) in mice reverses established insulin resistance and improves mitochondrial function in the context of diabetogenic stress. Specifically, skmSTX4tg reversed insulin resistance caused by high-fat diet (HFD) without altering body weight or food consumption. Electron microscopy of wild-type mouse muscle revealed STX4 localisation at or proximal to the mitochondrial membrane. STX4 enrichment prevented HFD-induced mitochondrial fragmentation and dysfunction through a mechanism involving STX4-Drp1 interaction and elevated AMPK-mediated phosphorylation at Drp1 S637, which favors fusion. Our findings challenge the dogma that STX4 acts solely at the plasma membrane, revealing that STX4 localises at/proximal to and regulates the function of mitochondria in muscle. These results establish skeletal muscle STX4 enrichment as a candidate therapeutic strategy to reverse peripheral insulin resistance.
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Affiliation(s)
- Karla E Merz
- Department of Molecular & Cellular Endocrinology, Arthur Riggs Diabetes and Metabolism Research Institute, City of Hope, Duarte, CA, USA
- Irell and Manella Graduate School of Biological Sciences, City of Hope, Duarte, CA, USA
- Amgen, Thousand Oaks, CA, USA
| | - Jinhee Hwang
- Department of Molecular & Cellular Endocrinology, Arthur Riggs Diabetes and Metabolism Research Institute, City of Hope, Duarte, CA, USA
| | - Chunxue Zhou
- Department of Molecular & Cellular Endocrinology, Arthur Riggs Diabetes and Metabolism Research Institute, City of Hope, Duarte, CA, USA
| | - Rajakrishnan Veluthakal
- Department of Molecular & Cellular Endocrinology, Arthur Riggs Diabetes and Metabolism Research Institute, City of Hope, Duarte, CA, USA
| | - Erika M McCown
- Department of Molecular & Cellular Endocrinology, Arthur Riggs Diabetes and Metabolism Research Institute, City of Hope, Duarte, CA, USA
| | - Angelica Hamilton
- Department of Molecular & Cellular Endocrinology, Arthur Riggs Diabetes and Metabolism Research Institute, City of Hope, Duarte, CA, USA
| | - Eunjin Oh
- Department of Molecular & Cellular Endocrinology, Arthur Riggs Diabetes and Metabolism Research Institute, City of Hope, Duarte, CA, USA
| | - Wenting Dai
- Department of Molecular & Cellular Endocrinology, Arthur Riggs Diabetes and Metabolism Research Institute, City of Hope, Duarte, CA, USA
| | - Patrick T Fueger
- Department of Molecular & Cellular Endocrinology, Arthur Riggs Diabetes and Metabolism Research Institute, City of Hope, Duarte, CA, USA
- Comprehensive Metabolic Phenotyping Core, Beckman Research Institute of City of Hope, Duarte, CA, USA
| | - Lei Jiang
- Department of Molecular & Cellular Endocrinology, Arthur Riggs Diabetes and Metabolism Research Institute, City of Hope, Duarte, CA, USA
| | - Janice M Huss
- Department of Molecular & Cellular Endocrinology, Arthur Riggs Diabetes and Metabolism Research Institute, City of Hope, Duarte, CA, USA
- Washington University School of Medicine, St. Louis, MO, USA
| | - Debbie C Thurmond
- Department of Molecular & Cellular Endocrinology, Arthur Riggs Diabetes and Metabolism Research Institute, City of Hope, Duarte, CA, USA.
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9
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Oh E, McCown EM, Ahn M, Garcia PA, Branciamore S, Tang S, Zeng DF, Roep BO, Thurmond DC. Syntaxin 4 Enrichment in β-Cells Prevents Conversion to Autoimmune Diabetes in Non-Obese Diabetic (NOD) Mice. Diabetes 2021; 70:2837-2849. [PMID: 34556496 PMCID: PMC8660989 DOI: 10.2337/db21-0170] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/25/2021] [Accepted: 09/07/2021] [Indexed: 11/13/2022]
Abstract
Syntaxin 4 (STX4), a plasma membrane-localized SNARE protein, regulates human islet β-cell insulin secretion and preservation of β-cell mass. We found that human type 1 diabetes (T1D) and NOD mouse islets show reduced β-cell STX4 expression, consistent with decreased STX4 expression, as a potential driver of T1D phenotypes. To test this hypothesis, we generated inducible β-cell-specific STX4-expressing NOD mice (NOD-iβSTX4). Of NOD-iβSTX4 mice, 73% had sustained normoglycemia vs. <20% of control NOD (NOD-Ctrl) mice by 25 weeks of age. At 12 weeks of age, before diabetes conversion, NOD-iβSTX4 mice demonstrated superior whole-body glucose tolerance and β-cell glucose responsiveness than NOD-Ctrl mice. Higher β-cell mass and reduced β-cell apoptosis were also detected in NOD-iβSTX4 pancreata compared with pancreata of NOD-Ctrl mice. Single-cell RNA sequencing revealed that islets from NOD-iβSTX4 had markedly reduced interferon-γ signaling and tumor necrosis factor-α signaling via nuclear factor-κB in islet β-cells, including reduced expression of the chemokine CCL5; CD4+ regulatory T cells were also enriched in NOD-iβSTX4 islets. These results provide a deeper mechanistic understanding of STX4 function in β-cell protection and warrant further investigation of STX4 enrichment as a strategy to reverse or prevent T1D in humans or protect β-cell grafts.
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Affiliation(s)
- Eunjin Oh
- Department of Molecular and Cellular Endocrinology, Arthur Riggs Diabetes and Metabolism Research Institute, City of Hope Beckman Research Institute, Duarte, CA
| | - Erika M McCown
- Department of Molecular and Cellular Endocrinology, Arthur Riggs Diabetes and Metabolism Research Institute, City of Hope Beckman Research Institute, Duarte, CA
| | - Miwon Ahn
- Department of Molecular and Cellular Endocrinology, Arthur Riggs Diabetes and Metabolism Research Institute, City of Hope Beckman Research Institute, Duarte, CA
| | - Pablo A Garcia
- Department of Molecular and Cellular Endocrinology, Arthur Riggs Diabetes and Metabolism Research Institute, City of Hope Beckman Research Institute, Duarte, CA
| | - Sergio Branciamore
- Department of Diabetes Complications and Metabolism, Arthur Riggs Diabetes and Metabolism Research Institute, City of Hope Beckman Research Institute, Duarte, CA
| | - Shanshan Tang
- Department of Immunology and Theranostics, Arthur Riggs Diabetes and Metabolism Research Institute, City of Hope Beckman Research Institute, Duarte, CA
| | - De-Fu Zeng
- Department of Immunology and Theranostics, Arthur Riggs Diabetes and Metabolism Research Institute, City of Hope Beckman Research Institute, Duarte, CA
| | - Bart O Roep
- Department of Diabetes Immunology, Arthur Riggs Diabetes and Metabolism Research Institute, City of Hope Beckman Research Institute, Duarte, CA
| | - Debbie C Thurmond
- Department of Molecular and Cellular Endocrinology, Arthur Riggs Diabetes and Metabolism Research Institute, City of Hope Beckman Research Institute, Duarte, CA
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Veluthakal R, Oh E, Ahn M, Chatterjee Bhowmick D, Thurmond DC. Syntaxin 4 Mediates NF-κB Signaling and Chemokine Ligand Expression via Specific Interaction With IκBβ. Diabetes 2021; 70:889-902. [PMID: 33526588 PMCID: PMC7980198 DOI: 10.2337/db20-0868] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/25/2020] [Accepted: 01/17/2021] [Indexed: 12/13/2022]
Abstract
Enrichment of human islets with syntaxin 4 (STX4) improves functional β-cell mass through a nuclear factor-κB (NF-κB)-dependent mechanism. However, the detailed mechanisms underlying the protective effect of STX4 are unknown. For determination of the signaling events linking STX4 enrichment and downregulation of NF-κB activity, STX4 was overexpressed in human islets, EndoC-βH1 and INS-1 832/13 cells in culture, and the cells were challenged with the proinflammatory cytokines interleukin-1β, tumor necrosis factor-α, and interferon-γ individually and in combination. STX4 expression suppressed cytokine-induced proteasomal degradation of IκBβ but not IκBα. Inhibition of IKKβ prevented IκBβ degradation, suggesting that IKKβ phosphorylates IκBβ. Moreover, the IKKβ inhibitor, as well as a proteosomal degradation inhibitor, prevented the loss of STX4 caused by cytokines. This suggests that STX4 may be phosphorylated by IKKβ in response to cytokines, targeting STX4 for proteosomal degradation. Expression of a stabilized form of STX4 further protected IκBβ from proteasomal degradation, and like wild-type STX4, stabilized STX4 coimmunoprecipitated with IκBβ and the p50-NF-κB. This work proposes a novel pathway wherein STX4 regulates cytokine-induced NF-κB signaling in β-cells via associating with and preventing IκBβ degradation, suppressing chemokine expression, and protecting islet β-cells from cytokine-mediated dysfunction and demise.
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Affiliation(s)
- Rajakrishnan Veluthakal
- Department of Molecular and Cellular Endocrinology, Arthur Riggs Diabetes and Metabolism Research Institute, City of Hope Beckman Research Institute, Duarte, CA
| | - Eunjin Oh
- Department of Molecular and Cellular Endocrinology, Arthur Riggs Diabetes and Metabolism Research Institute, City of Hope Beckman Research Institute, Duarte, CA
| | - Miwon Ahn
- Department of Molecular and Cellular Endocrinology, Arthur Riggs Diabetes and Metabolism Research Institute, City of Hope Beckman Research Institute, Duarte, CA
| | - Diti Chatterjee Bhowmick
- Department of Molecular and Cellular Endocrinology, Arthur Riggs Diabetes and Metabolism Research Institute, City of Hope Beckman Research Institute, Duarte, CA
| | - Debbie C Thurmond
- Department of Molecular and Cellular Endocrinology, Arthur Riggs Diabetes and Metabolism Research Institute, City of Hope Beckman Research Institute, Duarte, CA
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Conventional and Unconventional Mechanisms by which Exocytosis Proteins Oversee β-cell Function and Protection. Int J Mol Sci 2021; 22:ijms22041833. [PMID: 33673206 PMCID: PMC7918544 DOI: 10.3390/ijms22041833] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2021] [Revised: 02/02/2021] [Accepted: 02/08/2021] [Indexed: 02/06/2023] Open
Abstract
Type 2 diabetes (T2D) is one of the prominent causes of morbidity and mortality in the United States and beyond, reaching global pandemic proportions. One hallmark of T2D is dysfunctional glucose-stimulated insulin secretion from the pancreatic β-cell. Insulin is secreted via the recruitment of insulin secretory granules to the plasma membrane, where the soluble N-ethylmaleimide-sensitive factor attachment protein receptors (SNAREs) and SNARE regulators work together to dock the secretory granules and release insulin into the circulation. SNARE proteins and their regulators include the Syntaxins, SNAPs, Sec1/Munc18, VAMPs, and double C2-domain proteins. Recent studies using genomics, proteomics, and biochemical approaches have linked deficiencies of exocytosis proteins with the onset and progression of T2D. Promising results are also emerging wherein restoration or enhancement of certain exocytosis proteins to β-cells improves whole-body glucose homeostasis, enhances β-cell function, and surprisingly, protection of β-cell mass. Intriguingly, overexpression and knockout studies have revealed novel functions of certain exocytosis proteins, like Syntaxin 4, suggesting that exocytosis proteins can impact a variety of pathways, including inflammatory signaling and aging. In this review, we present the conventional and unconventional functions of β-cell exocytosis proteins in normal physiology and T2D and describe how these insights might improve clinical care for T2D.
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Sphingolipids in Type 1 Diabetes: Focus on Beta-Cells. Cells 2020; 9:cells9081835. [PMID: 32759843 PMCID: PMC7465050 DOI: 10.3390/cells9081835] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 08/01/2020] [Accepted: 08/03/2020] [Indexed: 12/28/2022] Open
Abstract
Type 1 diabetes (T1DM) is a chronic autoimmune disease, with a strong genetic background, leading to a gradual loss of pancreatic beta-cells, which secrete insulin and control glucose homeostasis. Patients with T1DM require life-long substitution with insulin and are at high risk for development of severe secondary complications. The incidence of T1DM has been continuously growing in the last decades, indicating an important contribution of environmental factors. Accumulating data indicates that sphingolipids may be crucially involved in T1DM development. The serum lipidome of T1DM patients is characterized by significantly altered sphingolipid composition compared to nondiabetic, healthy probands. Recently, several polymorphisms in the genes encoding the enzymatic machinery for sphingolipid production have been identified in T1DM individuals. Evidence gained from studies in rodent islets and beta-cells exposed to cytokines indicates dysregulation of the sphingolipid biosynthetic pathway and impaired function of several sphingolipids. Moreover, a number of glycosphingolipids have been suggested to act as beta-cell autoantigens. Studies in animal models of autoimmune diabetes, such as the Non Obese Diabetic (NOD) mouse and the LEW.1AR1-iddm (IDDM) rat, indicate a crucial role of sphingolipids in immune cell trafficking, islet infiltration and diabetes development. In this review, the up-to-date status on the findings about sphingolipids in T1DM will be provided, the under-investigated research areas will be identified and perspectives for future studies will be given.
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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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14
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Pang H, Luo S, Huang G, Xia Y, Xie Z, Zhou Z. Advances in Knowledge of Candidate Genes Acting at the Beta-Cell Level in the Pathogenesis of T1DM. Front Endocrinol (Lausanne) 2020; 11:119. [PMID: 32226409 PMCID: PMC7080653 DOI: 10.3389/fendo.2020.00119] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/16/2020] [Accepted: 02/24/2020] [Indexed: 12/12/2022] Open
Abstract
T1DM (type 1 diabetes mellitus), which results from the irreversible elimination of beta-cells mediated by autoreactive T cells, is defined as an autoimmune disease. It is widely accepted that T1DM is caused by a combination of genetic and environmental factors, but the precise underlying molecular mechanisms are still unknown. To date, more than 50 genetic risk regions contributing to the pathogenesis of T1DM have been identified by GWAS (genome-wide association studies). Notably, more than 60% of the identified candidate genes are expressed in islets and beta-cells, which makes it plausible that these genes act at the beta-cell level and play a key role in the pathogenesis of T1DM. In this review, we focus on the current status of candidate genes that act at the beta-cell level by regulating the innate immune response and antiviral activity, affecting susceptibility to proapoptotic stimuli and influencing the pancreatic beta-cell phenotype.
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Affiliation(s)
- Haipeng Pang
- Department of Metabolism and Endocrinology, The Second Xiangya Hospital, Central South University, Changsha, China
- Key Laboratory of Diabetes Immunology (Central South University), Ministry of Education, National Clinical Research Center for Metabolic Diseases, Changsha, China
| | - Shuoming Luo
- Department of Metabolism and Endocrinology, The Second Xiangya Hospital, Central South University, Changsha, China
- Key Laboratory of Diabetes Immunology (Central South University), Ministry of Education, National Clinical Research Center for Metabolic Diseases, Changsha, China
| | - Gan Huang
- Department of Metabolism and Endocrinology, The Second Xiangya Hospital, Central South University, Changsha, China
- Key Laboratory of Diabetes Immunology (Central South University), Ministry of Education, National Clinical Research Center for Metabolic Diseases, Changsha, China
| | - Ying Xia
- Department of Metabolism and Endocrinology, The Second Xiangya Hospital, Central South University, Changsha, China
- Key Laboratory of Diabetes Immunology (Central South University), Ministry of Education, National Clinical Research Center for Metabolic Diseases, Changsha, China
| | - Zhiguo Xie
- Department of Metabolism and Endocrinology, The Second Xiangya Hospital, Central South University, Changsha, China
- Key Laboratory of Diabetes Immunology (Central South University), Ministry of Education, National Clinical Research Center for Metabolic Diseases, Changsha, China
- *Correspondence: Zhiguo Xie
| | - Zhiguang Zhou
- Department of Metabolism and Endocrinology, The Second Xiangya Hospital, Central South University, Changsha, China
- Key Laboratory of Diabetes Immunology (Central South University), Ministry of Education, National Clinical Research Center for Metabolic Diseases, Changsha, China
- Zhiguang Zhou
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