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Monteiro-Cardoso VF, Giordano F. Emerging functions of the mitochondria-ER-lipid droplet three-way junction in coordinating lipid transfer, metabolism, and storage in cells. FEBS Lett 2024; 598:1252-1273. [PMID: 38774950 DOI: 10.1002/1873-3468.14893] [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: 02/05/2024] [Revised: 03/18/2024] [Accepted: 04/05/2024] [Indexed: 05/25/2024]
Abstract
Over the past two decades, we have witnessed a growing appreciation for the importance of membrane contact sites (CS) in facilitating direct communication between organelles. CS are tiny regions where the membranes of two organelles meet but do not fuse and allow the transfer of metabolites between organelles, playing crucial roles in the coordination of cellular metabolic activities. The significant advancements in imaging techniques and molecular and cell biology research have revealed that CS are more complex than what originally thought, and as they are extremely dynamic, they can remodel their shape, composition, and functions in accordance with metabolic and environmental changes and can occur between more than two organelles. Here, we describe how recent studies led to the identification of a three-way mitochondria-ER-lipid droplet CS and discuss the emerging functions of these contacts in maintaining lipid storage, homeostasis, and balance. We also summarize the properties and functions of key protein components localized at the mitochondria-ER-lipid droplet interface, with a special focus on lipid transfer proteins. Understanding tripartite CS is essential for unraveling the complexities of inter-organelle communication and cooperation within cells.
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Affiliation(s)
- Vera Filipa Monteiro-Cardoso
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Saclay, Gif-sur-Yvette cedex, France
- Inserm U1280, Gif-sur-Yvette cedex, France
| | - Francesca Giordano
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Saclay, Gif-sur-Yvette cedex, France
- Inserm U1280, Gif-sur-Yvette cedex, France
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2
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Shu C, Yu Y, Xiaopan Chen, Guo J, Zhou Y, Wu D, Yang T, Fan Y, Huang Q, Shu J. Three-dimensional architecture of granulosa cell derived from oocyte cumulus complex, revealed by FIB-SEM. J Ovarian Res 2023; 16:213. [PMID: 37946316 PMCID: PMC10633969 DOI: 10.1186/s13048-023-01298-9] [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: 02/03/2023] [Accepted: 10/13/2023] [Indexed: 11/12/2023] Open
Abstract
The oocyte cumulus complex is mainly composed of an oocyte, the perivitelline space, zona pellucida and numerous granulosa cells. The cumulus granulosa cells (cGCs) provide a particularly important microenvironment for oocyte development, regulating its growth, maturation and meiosis. In this study, we studied the internal structures and cell-to-cell connections of mouse cGCs using focused ion beam scanning electron microscopy (FIB-SEM). We reconstructed three-dimensional models to display characteristic connections between the oocyte and cGCs, and to illustrate various main organelles in cGCs together with their interaction relationship. A special form of cilium identified in granulosa cell was never reported in previous literature.
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Affiliation(s)
- Chongyi Shu
- Center for Reproductive Medicine, Department of Reproductive Endocrinology, Zhejiang Provincial People's Hospital (Affiliated People's Hospital, Hangzhou Medical College), Hangzhou, China
| | - Yiqi Yu
- Center for Reproductive Medicine, Department of Reproductive Endocrinology, Zhejiang Provincial People's Hospital (Affiliated People's Hospital, Hangzhou Medical College), Hangzhou, China
| | - Xiaopan Chen
- Center for Reproductive Medicine, Department of Reproductive Endocrinology, Zhejiang Provincial People's Hospital (Affiliated People's Hospital, Hangzhou Medical College), Hangzhou, China
- Department of Genetic and Genomic Medicine, Zhejiang Provincial People's Hospital, (Affiliated People's Hospital, Hangzhou Medical College), Hangzhou, China
| | - Jiansheng Guo
- School of Medicine, Zhejiang University, Hangzhou, 310058, China
| | - Yier Zhou
- Center for Reproductive Medicine, Department of Reproductive Endocrinology, Zhejiang Provincial People's Hospital (Affiliated People's Hospital, Hangzhou Medical College), Hangzhou, China
| | - Dandan Wu
- Department of Obstetrics, Zhejiang Hospital, Hangzhou, 310012, China
| | - Tianyun Yang
- Center for Reproductive Medicine, Department of Reproductive Endocrinology, Zhejiang Provincial People's Hospital (Affiliated People's Hospital, Hangzhou Medical College), Hangzhou, China
| | - Yuhang Fan
- Center for Reproductive Medicine, Department of Reproductive Endocrinology, Zhejiang Provincial People's Hospital (Affiliated People's Hospital, Hangzhou Medical College), Hangzhou, China
| | - Qiongxiao Huang
- Center for Reproductive Medicine, Department of Reproductive Endocrinology, Zhejiang Provincial People's Hospital (Affiliated People's Hospital, Hangzhou Medical College), Hangzhou, China.
| | - Jing Shu
- Center for Reproductive Medicine, Department of Reproductive Endocrinology, Zhejiang Provincial People's Hospital (Affiliated People's Hospital, Hangzhou Medical College), Hangzhou, China.
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Gentile GM, Gamarra JR, Engels NM, Blue RE, Hoerr I, Wiedner HJ, Hinkle ER, Cote JL, Leverence E, Mills CA, Herring LE, Tan X, Giudice J. The synaptosome-associated protein 23 (SNAP23) is necessary for proper myogenesis. FASEB J 2022; 36:e22441. [PMID: 35816155 PMCID: PMC9836321 DOI: 10.1096/fj.202101627rr] [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: 10/20/2021] [Revised: 06/17/2022] [Accepted: 06/24/2022] [Indexed: 01/14/2023]
Abstract
Vesicle-mediated transport is necessary for maintaining cellular homeostasis and proper signaling. The synaptosome-associated protein 23 (SNAP23) is a member of the SNARE protein family and mediates the vesicle docking and membrane fusion steps of secretion during exocytosis. Skeletal muscle has been established as a secretory organ; however, the role of SNAP23 in the context of skeletal muscle development is still unknown. Here, we show that depletion of SNAP23 in C2C12 mouse myoblasts reduces their ability to differentiate into myotubes as a result of premature cell cycle exit and early activation of the myogenic transcriptional program. This effect is rescued when cells are seeded at a high density or when cultured in conditioned medium from wild type cells. Proteomic analysis of collected medium indicates that SNAP23 depletion leads to a misregulation of exocytosis, including decreased secretion of the insulin-like growth factor 1 (IGF1), a critical protein for muscle growth, development, and function. We further demonstrate that treatment of SNAP23-depleted cells with exogenous IGF1 rescues their myogenic capacity. We propose that SNAP23 mediates the secretion of specific proteins, such as IGF1, that are important for achieving proper differentiation of skeletal muscle cells during myogenesis. This work highlights the underappreciated role of skeletal muscle as a secretory organ and contributes to the understanding of factors necessary for myogenesis.
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Affiliation(s)
- Gabrielle M. Gentile
- Department of Cell Biology and Physiology, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
- Curriculum in Genetics and Molecular Biology, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Jennifer R. Gamarra
- Department of Cell Biology and Physiology, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Nichlas M. Engels
- Department of Cell Biology and Physiology, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - R. Eric Blue
- Department of Cell Biology and Physiology, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Isabel Hoerr
- Department of Cell Biology and Physiology, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Hannah J. Wiedner
- Department of Cell Biology and Physiology, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
- Curriculum in Genetics and Molecular Biology, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Emma R. Hinkle
- Department of Cell Biology and Physiology, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
- Curriculum in Genetics and Molecular Biology, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Jessica L. Cote
- Department of Cell Biology and Physiology, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Elise Leverence
- Department of Cell Biology and Physiology, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Christine A. Mills
- UNC Proteomics Core Facility, Department of Pharmacology, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Laura E. Herring
- UNC Proteomics Core Facility, Department of Pharmacology, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Xianming Tan
- Department of Biostatistics, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
- Lineberger Comprehensive Cancer Center, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Jimena Giudice
- Department of Cell Biology and Physiology, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
- Curriculum in Genetics and Molecular Biology, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
- McAllister Heart Institute, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
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Hwang J, Thurmond DC. Exocytosis Proteins: Typical and Atypical Mechanisms of Action in Skeletal Muscle. Front Endocrinol (Lausanne) 2022; 13:915509. [PMID: 35774142 PMCID: PMC9238359 DOI: 10.3389/fendo.2022.915509] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/08/2022] [Accepted: 05/11/2022] [Indexed: 11/18/2022] Open
Abstract
Insulin-stimulated glucose uptake in skeletal muscle is of fundamental importance to prevent postprandial hyperglycemia, and long-term deficits in insulin-stimulated glucose uptake underlie insulin resistance and type 2 diabetes. Skeletal muscle is responsible for ~80% of the peripheral glucose uptake from circulation via the insulin-responsive glucose transporter GLUT4. GLUT4 is mainly sequestered in intracellular GLUT4 storage vesicles in the basal state. In response to insulin, the GLUT4 storage vesicles rapidly translocate to the plasma membrane, where they undergo vesicle docking, priming, and fusion via the high-affinity interactions among the soluble N-ethylmaleimide sensitive factor attachment protein receptor (SNARE) exocytosis proteins and their regulators. Numerous studies have elucidated that GLUT4 translocation is defective in insulin resistance and type 2 diabetes. Emerging evidence also links defects in several SNAREs and SNARE regulatory proteins to insulin resistance and type 2 diabetes in rodents and humans. Therefore, we highlight the latest research on the role of SNAREs and their regulatory proteins in insulin-stimulated GLUT4 translocation in skeletal muscle. Subsequently, we discuss the novel emerging role of SNARE proteins as interaction partners in pathways not typically thought to involve SNAREs and how these atypical functions reveal novel therapeutic targets for combating peripheral insulin resistance and diabetes.
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Affiliation(s)
| | - Debbie C. Thurmond
- Department of Molecular and Cellular Endocrinology, Arthur Riggs Diabetes and Metabolism Research Institute, Beckman Research Institute at City of Hope, Duarte, CA, United States
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Leitner N, Hlavaty J, Heider S, Ertl R, Gabriel C, Walter I. Lipid droplet dynamics in healthy and pyometra-affected canine endometrium. BMC Vet Res 2022; 18:221. [PMID: 35689217 PMCID: PMC9188128 DOI: 10.1186/s12917-022-03321-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2022] [Accepted: 05/20/2022] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Accumulation of lipid droplets (LDs) was recently observed in pyometra-affected uteri. As data about their nature and function are missing we intended to compare the localization, quality and quantity of LDs in canine healthy and pyometra-affected tissues and in an in vitro model. METHODS AND RESULTS We characterized LDs in healthy and pyometra uterine tissue samples as well as in canine endometrial epithelial cells (CEECs) in vitro by means of histochemistry, immunohistochemistry, transmission electron microscopy, western blot, and RT-qPCR. Oil Red O (ORO) staining and quantification as well as p-phenylenediamine staining showed a higher number of LDs in epithelial cells of pyometra samples. Immunohistochemistry revealed that the amount of LDs coated by perilipin2 (PLIN2) protein was also higher in pyometra samples. Transmission electron microscopy showed an increase of LD size in surface and glandular epithelial cells of pyometra samples. In cell culture experiments with CEECs, supplementation with oleic acid alone or in combination with cholesterol lead to an increased LD accumulation. The expression of PLIN2 at protein and mRNA level was also higher upon oleic acid supplementation. Most LDs were double positive for ORO and PLIN2. However, ORO positive LDs lacking PLIN2 coating or LDs positive for PLIN2 but containing a lipid class not detectable by ORO staining were identified. CONCLUSIONS We found differences in the healthy and pyometra-affected endometrium with respect to LDs size. Moreover, several kinds of LDs seem to be present in the canine endometrium. In vitro studies with CEECs could show their responsiveness to external lipids. Since epithelial cells reacted only to oleic acid stimulation, we assume that the cyclic lipid accumulation in the canine endometrium is based mainly on triglycerides and might serve as energy provision for the developing early embryo. Further studies are necessary to verify the complex role of lipids in the healthy and pyometra-affected canine endometrium.
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Affiliation(s)
- Natascha Leitner
- Institute of Morphology, Working Group Histology, University of Veterinary Medicine, Veterinaerplatz 1, A-1210, Vienna, Austria
| | - Juraj Hlavaty
- Institute of Morphology, Working Group Histology, University of Veterinary Medicine, Veterinaerplatz 1, A-1210, Vienna, Austria
| | - Susanne Heider
- Institute of Morphology, Working Group Histology, University of Veterinary Medicine, Veterinaerplatz 1, A-1210, Vienna, Austria
| | - Reinhard Ertl
- VetCORE Facility for Research, University of Veterinary Medicine, Veterinaerplatz 1, A-1210, Vienna, Austria
| | - Cordula Gabriel
- Institute of Morphology, Working Group Histology, University of Veterinary Medicine, Veterinaerplatz 1, A-1210, Vienna, Austria
| | - Ingrid Walter
- Institute of Morphology, Working Group Histology, University of Veterinary Medicine, Veterinaerplatz 1, A-1210, Vienna, Austria. .,VetCORE Facility for Research, University of Veterinary Medicine, Veterinaerplatz 1, A-1210, Vienna, Austria.
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6
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Liao PC, Yang EJ, Borgman T, Boldogh IR, Sing CN, Swayne TC, Pon LA. Touch and Go: Membrane Contact Sites Between Lipid Droplets and Other Organelles. Front Cell Dev Biol 2022; 10:852021. [PMID: 35281095 PMCID: PMC8908909 DOI: 10.3389/fcell.2022.852021] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2022] [Accepted: 02/03/2022] [Indexed: 12/26/2022] Open
Abstract
Lipid droplets (LDs) have emerged not just as storage sites for lipids but as central regulators of metabolism and organelle quality control. These critical functions are achieved, in part, at membrane contact sites (MCS) between LDs and other organelles. MCS are sites of transfer of cellular constituents to or from LDs for energy mobilization in response to nutrient limitations, as well as LD biogenesis, expansion and autophagy. Here, we describe recent findings on the mechanisms underlying the formation and function of MCS between LDs and mitochondria, ER and lysosomes/vacuoles and the role of the cytoskeleton in promoting LD MCS through its function in LD movement and distribution in response to environmental cues.
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Affiliation(s)
- Pin-Chao Liao
- Department of Pathology and Cell Biology, Columbia University Irving Medical Center, New York, NY, United States
- Institute of Molecular Medicine, National Tsing Hua University, Hsinchu, Taiwan
| | - Emily J. Yang
- Department of Pathology and Cell Biology, Columbia University Irving Medical Center, New York, NY, United States
| | - Taylor Borgman
- Institute of Human Nutrition, Columbia University Irving Medical Center, New York, NY, United States
| | - Istvan R. Boldogh
- Department of Pathology and Cell Biology, Columbia University Irving Medical Center, New York, NY, United States
- Herbert Irving Comprehensive Cancer Center, Columbia University Irving Medical Center, New York, NY, United States
| | - Cierra N. Sing
- Institute of Human Nutrition, Columbia University Irving Medical Center, New York, NY, United States
| | - Theresa C. Swayne
- Herbert Irving Comprehensive Cancer Center, Columbia University Irving Medical Center, New York, NY, United States
| | - Liza A. Pon
- Department of Pathology and Cell Biology, Columbia University Irving Medical Center, New York, NY, United States
- Institute of Human Nutrition, Columbia University Irving Medical Center, New York, NY, United States
- *Correspondence: Liza A. Pon,
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7
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Yang M, Luo S, Yang J, Chen W, He L, Liu D, Zhao L, Wang X. Lipid droplet - mitochondria coupling: A novel lipid metabolism regulatory hub in diabetic nephropathy. Front Endocrinol (Lausanne) 2022; 13:1017387. [PMID: 36387849 PMCID: PMC9640443 DOI: 10.3389/fendo.2022.1017387] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/12/2022] [Accepted: 10/04/2022] [Indexed: 11/13/2022] Open
Abstract
Diabetic nephropathy (DN) involves serious lipid metabolism disorder, and renal ectopic lipid deposition aggravates DN progression. However, the molecular mechanism of renal lipid deposition in DN remains unclear. Lipid droplets (LDs) are lipid pools in cells that change dynamically in response to the cellular energy needs. The LDs and mitochondria are connected through a part of the mitochondria known as the peridroplet mitochondria (PDM). In this review, we summarize the definition, detection methods, and function of the PDM. Finally, we discuss the research status of PDM in DN and the possibility of its use as a therapeutic target.
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Affiliation(s)
- Ming Yang
- Department of Nutrition, Xiangya Hospital, Central South University, Changsha, China
- Department of Nephrology, The Second Xiangya Hospital of Central South University, Changsha, China
| | - Shilu Luo
- Department of Nephrology, The Second Xiangya Hospital of Central South University, Changsha, China
| | - Jinfei Yang
- Department of Nephrology, The Second Xiangya Hospital of Central South University, Changsha, China
| | - Wei Chen
- Department of Nephrology, The Second Xiangya Hospital of Central South University, Changsha, China
| | - Liyu He
- Department of Nephrology, The Second Xiangya Hospital of Central South University, Changsha, China
| | - Di Liu
- Department of Nephrology, The Second Xiangya Hospital of Central South University, Changsha, China
| | - Li Zhao
- Department of Reproduction and Genetics, The First Affiliated Hospital of Kunming Medical University, Kunming, China
| | - Xi Wang
- Department of Nutrition, Xiangya Hospital, Central South University, Changsha, China
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, China
- *Correspondence: Xi Wang,
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8
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Liu YD, Zhuang XP, Cai DL, Cao C, Gu QS, Liu XN, Zheng BB, Guan BJ, Yu L, Li JK, Ding HB, Yan DW. Let-7a regulates EV secretion and mitochondrial oxidative phosphorylation by targeting SNAP23 in colorectal cancer. JOURNAL OF EXPERIMENTAL & CLINICAL CANCER RESEARCH : CR 2021; 40:31. [PMID: 33446221 PMCID: PMC7807815 DOI: 10.1186/s13046-020-01813-6] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/27/2020] [Accepted: 12/11/2020] [Indexed: 12/24/2022]
Abstract
Background MicroRNAs (miRNAs) are abundant in tumor-derived extracellular vesicles (EVs) and the functions of extracellular miRNA to recipient cells have been extensively studied with tumorigenesis. However, the role of miRNA in EV secretion from cancer cells remains unknown. Methods qPCR and bioinformatics analysis were applied for determining extracellular let-7a expression from CRC patient serum and cells. Nanosight particle tracking analysis was performed for investigating the effect of let-7a on EV secretion. Luciferase reporter assays was used for identifying targeted genes synaptosome-associated protein 23 (SNAP23). In vitro and in vivo assays were used for exploring the function of let-7a/SNAP23 axis in CRC progression. Bioenergetic assays were performed for investigating the role of let-7a/SNAP23 in cellular metabolic reprogramming. Results let-7a miRNA was elevated in serum EVs from CRC patients and was enriched in CRC cell-derived EVs. We determined that let-7a could suppress EV secretion directly targeting SNAP23. In turn, SNAP23 promotes EV secretion of let-7a to downregulate the intracellular let-7a expression. In addition, we found a novel mechanism of let-7a/SNAP23 axis by regulating mitochondrial oxidative phosphorylation (OXPHOS) through Lin28a/SDHA signaling pathway. Conclusions Let-7a plays an essential role in not only inhibiting EV secretion, but also suppressing OXPHOS through SNAP23, resulting in the suppression of CRC progression, suggesting that let-7a/SNAP23 axis could provide not only effective tumor biomarkers but also novel targets for tumor therapeutic strategies. Supplementary Information The online version contains supplementary material available at 10.1186/s13046-020-01813-6.
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Affiliation(s)
- You Dong Liu
- Department of General Surgery, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200080, China
| | - Xiao Peng Zhuang
- Department of General Surgery, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200080, China
| | - Dong Lan Cai
- Department of Ophthalmology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200080, China
| | - Can Cao
- Department of General Surgery, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200080, China
| | - Qi Sheng Gu
- Department of General Surgery, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200080, China
| | - Xue Ni Liu
- Department of General Surgery, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200080, China
| | - Bin Bin Zheng
- Department of General Surgery, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200080, China
| | - Bing Jie Guan
- Department of General Surgery, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200080, China
| | - Liang Yu
- Department of General Surgery, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200080, China
| | - Ji Kun Li
- Department of General Surgery, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200080, China
| | - Hui Bin Ding
- Department of General Surgery, The People's Hospital of Rugao, Rugao, Jiangsu, 226500, China.
| | - Dong Wang Yan
- Department of General Surgery, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200080, China.
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Seibert JT, Najt CP, Heden TD, Mashek DG, Chow LS. Muscle Lipid Droplets: Cellular Signaling to Exercise Physiology and Beyond. Trends Endocrinol Metab 2020; 31:928-938. [PMID: 32917515 PMCID: PMC7704552 DOI: 10.1016/j.tem.2020.08.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/01/2020] [Revised: 07/09/2020] [Accepted: 08/13/2020] [Indexed: 12/21/2022]
Abstract
Conventionally viewed as energy storage depots, lipid droplets (LDs) play a central role in muscle lipid metabolism and intracellular signaling, as recognized by recent advances in our biological understanding. Specific subpopulations of muscle LDs, defined by location and associated proteins, are responsible for distinct biological functions. In this review, the traditional view of muscle LDs is examined, and the emerging role of LDs in intracellular signaling is highlighted. The effects of chronic and acute exercise on muscle LD metabolism and signaling is discussed. In conclusion, future directions for muscle LD research are identified. The primary focus will be on human studies, with inclusion of select animal/cellular/non-muscle studies as appropriate, to provide the underlying mechanisms driving the observed findings.
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Affiliation(s)
- Jacob T Seibert
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA
| | - Charles P Najt
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA
| | - Timothy D Heden
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA
| | - Douglas G Mashek
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA; Department of Medicine, Division of Diabetes, Endocrinology and Metabolism, University of Minnesota, Minneapolis, MN 55455, USA
| | - Lisa S Chow
- Department of Medicine, Division of Diabetes, Endocrinology and Metabolism, University of Minnesota, Minneapolis, MN 55455, USA.
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10
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Whytock KL, Parry SA, Turner MC, Woods RM, James LJ, Ferguson RA, Ståhlman M, Borén J, Strauss JA, Cocks M, Wagenmakers AJM, Hulston CJ, Shepherd SO. A 7‐day high‐fat, high‐calorie diet induces fibre‐specific increases in intramuscular triglyceride and perilipin protein expression in human skeletal muscle. J Physiol 2020; 598:1151-1167. [DOI: 10.1113/jp279129] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2019] [Accepted: 01/13/2020] [Indexed: 12/24/2022] Open
Affiliation(s)
- K. L. Whytock
- Research Institute of Sport and Exercise Science, Tom Reilly Building LJMU Liverpool L3 3AF UK
| | - S. A. Parry
- School of Sport, Exercise and Health Sciences Loughborough University Loughborough LE11 3TU UK
| | - M. C. Turner
- School of Sport, Exercise and Health Sciences Loughborough University Loughborough LE11 3TU UK
| | - R. M. Woods
- School of Sport, Exercise and Health Sciences Loughborough University Loughborough LE11 3TU UK
| | - L. J. James
- School of Sport, Exercise and Health Sciences Loughborough University Loughborough LE11 3TU UK
| | - R. A. Ferguson
- School of Sport, Exercise and Health Sciences Loughborough University Loughborough LE11 3TU UK
| | - M. Ståhlman
- Wallenberg Laboratory, Sahlgrenska Academy University of Gothenburg Gothenburg Sweden
| | - J. Borén
- Wallenberg Laboratory, Sahlgrenska Academy University of Gothenburg Gothenburg Sweden
| | - J. A. Strauss
- Research Institute of Sport and Exercise Science, Tom Reilly Building LJMU Liverpool L3 3AF UK
| | - M. Cocks
- Research Institute of Sport and Exercise Science, Tom Reilly Building LJMU Liverpool L3 3AF UK
| | - A. J. M. Wagenmakers
- Research Institute of Sport and Exercise Science, Tom Reilly Building LJMU Liverpool L3 3AF UK
| | - C. J. Hulston
- School of Sport, Exercise and Health Sciences Loughborough University Loughborough LE11 3TU UK
| | - S. O. Shepherd
- Research Institute of Sport and Exercise Science, Tom Reilly Building LJMU Liverpool L3 3AF UK
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11
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Formation and degradation of lipid droplets in human adipocytes and the expression of aldehyde oxidase (AOX). Cell Tissue Res 2019; 379:45-62. [DOI: 10.1007/s00441-019-03152-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
AbstractLipid droplet (LD) binding proteins in mammary glands and in adipocytes were previously compared and striking similar sets of these specific proteins demonstrated. Xanthine oxidoreductase (XOR) together with perilipins and the lactating mammary gland protein butyrophilin play an important role in the secretion process of LDs into milk ducts. In contrast, in adipose tissue and in adipocytes, mainly perilipins have been described. Moreover, XOR was reported in mouse adipose tissue and adipocyte culture cells as “novel regulator of adipogenesis”. This obvious coincidence of protein sets prompted us to revisit the formation of LDs in human-cultured adipocytes in more detail with special emphasis on the possibility of a LD association of XOR. We demonstrate by electron and immunoelectron microscopy new structural details on LD formation in adipocytes. Surprisingly, by immunological and proteomic analysis, we identify in contrast to previous data showing the enzyme XOR, predominantly the expression of aldehyde oxidase (AOX). AOX could be detected tightly linked to LDs when adipocytes were treated with starvation medium. In addition, the majority of cells show an enormous interconnected, tubulated mitochondria network. Here, we discuss that (1) XOR is involved—together with perilipins—in the secretion of LDs in alveolar epithelial cells of the lactating mammary gland and is important in the transcytosis pathway of capillary endothelial cells. (2) In cells, where LDs are not secreted, XOR cannot be detected at the protein level, whereas in contrast in these cases, AOX is often present. We detect AOX in adipocytes together with perilipins and find evidence that these proteins might direct LDs to mitochondria. Finally, we here report for the first time the exclusive and complementary localization of XOR and AOX in diverse cell types.
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Young PA, Senkal CE, Suchanek AL, Grevengoed TJ, Lin DD, Zhao L, Crunk AE, Klett EL, Füllekrug J, Obeid LM, Coleman RA. Long-chain acyl-CoA synthetase 1 interacts with key proteins that activate and direct fatty acids into niche hepatic pathways. J Biol Chem 2018; 293:16724-16740. [PMID: 30190326 DOI: 10.1074/jbc.ra118.004049] [Citation(s) in RCA: 61] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2018] [Revised: 08/24/2018] [Indexed: 12/17/2022] Open
Abstract
Fatty acid channeling into oxidation or storage modes depends on physiological conditions and hormonal signaling. However, the directionality of this channeling may also depend on the association of each of the five acyl-CoA synthetase isoforms with specific protein partners. Long-chain acyl-CoA synthetases (ACSLs) catalyze the conversion of long-chain fatty acids to fatty acyl-CoAs, which are then either oxidized or used in esterification reactions. In highly oxidative tissues, ACSL1 is located on the outer mitochondrial membrane (OMM) and directs fatty acids into mitochondria for β-oxidation. In the liver, however, about 50% of ACSL1 is located on the endoplasmic reticulum (ER) where its metabolic function is unclear. Because hepatic fatty acid partitioning is likely to require the interaction of ACSL1 with other specific proteins, we used an unbiased protein interaction technique, BioID, to discover ACSL1-binding partners in hepatocytes. We targeted ACSL1 either to the ER or to the OMM of Hepa 1-6 cells as a fusion protein with the Escherichia coli biotin ligase, BirA*. Proteomic analysis identified 98 proteins that specifically interacted with ACSL1 at the ER, 55 at the OMM, and 43 common to both subcellular locations. We found subsets of peroxisomal and lipid droplet proteins, tethering proteins, and vesicle proteins, uncovering a dynamic role for ACSL1 in organelle and lipid droplet interactions. Proteins involved in lipid metabolism were also identified, including acyl-CoA-binding proteins and ceramide synthase isoforms 2 and 5. Our results provide fundamental and detailed insights into protein interaction networks that control fatty acid metabolism.
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Affiliation(s)
| | - Can E Senkal
- the Department of Medicine, Stony Brook University, Stony Brook, New York 11794, and
| | | | | | | | | | | | - Eric L Klett
- From the Departments of Nutrition and.,Medicine, University of North Carolina, Chapel Hill, North Carolina 27599
| | - Joachim Füllekrug
- the Molecular Cell Biology Laboratory, Internal Medicine IV, Heidelberg University Hospital, Otto-Meyerhof-Zentrum, University of Heidelberg, 69120 Heidelberg, Germany
| | - Lina M Obeid
- the Department of Medicine, Stony Brook University, Stony Brook, New York 11794, and
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Ectopic BAT mUCP-1 overexpression in SKM by delivering a BMP7/PRDM16/PGC-1a gene cocktail or single PRMD16 using non-viral UTMD gene therapy. Gene Ther 2018; 25:497-509. [PMID: 30072816 DOI: 10.1038/s41434-018-0036-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2018] [Revised: 06/19/2018] [Accepted: 06/28/2018] [Indexed: 02/06/2023]
Abstract
Here we present our progress in inducing an ectopic brown adipose tissue (BAT) phenotype in skeletal muscle (SKM) as a potential gene therapy for obesity and its comorbidities. We used ultrasound-targeted microbubble destruction (UTMD), a novel targeted, non-viral approach to gene therapy, to deliver genes in the BAT differentiation pathway into rodent SKM to engineer a thermogenic BAT phenotype with ectopic mUCP-1 overexpression. In parallel, we performed a second protocol using wild-type Ucp-1-null knockout mice to test whether the effects of the gene therapy are UCP-1 dependent. Our main findings were a robust cellular presence of mUCP-1 immunostaining (IHC), significantly higher expression levels of mUCP-1 measured by qRT-PCR, and highest temperature elevation measured by infrared thermography in the treated thigh, achieved in rats after delivering the UTMD-PRDM16/PGC-1a/BMP7/hyPB gene cocktail. Interestingly, the weight loss obtained in the treated rats with the triple gene delivery, never recovered the levels observed in the controls in spite of food intake recovery. Our results establish the feasibility of minimally invasive UTMD gene-based therapy administration in SKM, to induce overexpression of ectopic mUCP-1 after delivery of the thermogenic BAT gene program, and describe systemic effects of this intervention on food intake, weight loss, and thermogenesis.
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Whytock KL, Shepherd SO, Wagenmakers AJM, Strauss JA. Hormone-sensitive lipase preferentially redistributes to lipid droplets associated with perilipin-5 in human skeletal muscle during moderate-intensity exercise. J Physiol 2018. [PMID: 29527681 DOI: 10.1113/jp275502] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
KEY POINTS Hormone-sensitive lipase (HSL) and adipose triglyceride lipase (ATGL) are the key enzymes involved in intramuscular triglyceride (IMTG) lipolysis. In isolated rat skeletal muscle, HSL translocates to IMTG-containing lipid droplets (LDs) following electrical stimulation, but whether HSL translocation occurs in human skeletal muscle during moderate-intensity exercise is currently unknown. Perilipin-2 (PLIN2) and perilipin-5 (PLIN5) proteins have been implicated in regulating IMTG lipolysis by interacting with HSL and ATGL in cell culture and rat skeletal muscle studies. This study investigated the hypothesis that HSL (but not ATGL) redistributes to LDs during moderate-intensity exercise in human skeletal muscle, and whether the localisation of these lipases with LDs was affected by the presence of PLIN proteins on the LDs. HSL preferentially redistributed to PLIN5-associated LDs whereas ATGL distribution was not altered with exercise; this is the first study to illustrate the pivotal step of HSL redistribution to PLIN5-associated LDs following moderate-intensity exercise in human skeletal muscle. ABSTRACT Hormone-sensitive lipase (HSL) and adipose triglyceride lipase (ATGL) control skeletal muscle lipolysis. ATGL is present on the surface of lipid droplets (LDs) containing intramuscular triglyceride (IMTG) in both the basal state and during exercise. HSL translocates to LD in ex vivo electrically stimulated rat skeletal muscle. Perilipin-2- and perilipin-5-associated lipid droplets (PLIN2+ and PLIN5+ LDs) are preferentially depleted during exercise in humans, indicating that these PLINs may control muscle lipolysis. We aimed to test the hypothesis that in human skeletal muscle in vivo HSL (but not ATGL) is redistributed to PLIN2+ and PLIN5+ LDs during moderate-intensity exercise. Muscle biopsies from 8 lean trained males (age 21 ± 1 years, BMI 22.6 ± 1.2 kg m-2 and V̇O2 peak 48.2 ± 5.0 ml min-1 kg-1 ) were obtained before and immediately following 60 min of cycling exercise at ∼59% V̇O2 peak . Cryosections were stained using antibodies targeting ATGL, HSL, PLIN2 and PLIN5. LDs were stained using BODIPY 493/503. Images were obtained using confocal immunofluorescence microscopy and object-based colocalisation analyses were performed. Following exercise, HSL colocalisation to LDs increased (P < 0.05), and was significantly greater to PLIN5+ LDs (+53%) than to PLIN5- LDs (+34%) (P < 0.05), while the increases in HSL colocalisation to PLIN2+ LDs (+16%) and PLIN2- LDs (+28%) were not significantly different. Following exercise, the fraction of LDs colocalised with ATGL (0.53 ± 0.04) did not significantly change (P < 0.05) and was not affected by PLIN association to the LDs. This study presents the first evidence of exercise-induced HSL redistribution to LDs in human skeletal muscle and identifies PLIN5 as a facilitator of this mechanism.
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Affiliation(s)
- Katie L Whytock
- Research Institute for Sport and Exercise Science, Liverpool John Moores University, Liverpool L3 3AF, UK
| | - Sam O Shepherd
- Research Institute for Sport and Exercise Science, Liverpool John Moores University, Liverpool L3 3AF, UK
| | - Anton J M Wagenmakers
- Research Institute for Sport and Exercise Science, Liverpool John Moores University, Liverpool L3 3AF, UK
| | - Juliette A Strauss
- Research Institute for Sport and Exercise Science, Liverpool John Moores University, Liverpool L3 3AF, UK
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Crossreactivity of an Antiserum Directed to the Gram-Negative Bacterium Neisseria gonorrhoeae with the SNARE-Complex Protein Snap23 Correlates to Impaired Exocytosis in SH-SY5Y Cells. J Mol Neurosci 2017; 62:163-180. [PMID: 28462458 DOI: 10.1007/s12031-017-0920-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2016] [Accepted: 04/10/2017] [Indexed: 02/04/2023]
Abstract
Early maternal infections with Neisseria gonorrhoeae (NG) correlate to an increased lifetime schizophrenia risk for the offspring, which might be due to an immune-mediated mechanism. Here, we investigated the interactions of polyclonal antisera to NG (α-NG) with a first trimester prenatal brain multiprotein array, revealing among others the SNARE-complex protein Snap23 as a target antigen for α-NG. This interaction was confirmed by Western blot analysis with a recombinant Snap23 protein, whereas the closely related Snap25 failed to interact with α-NG. Furthermore, a polyclonal antiserum to the closely related bacterium Neisseria meningitidis (α-NM) failed to interact with both proteins. Functionally, in SH-SY5Y cells, α-NG pretreatment interfered with both insulin-induced vesicle recycling, as revealed by uptake of the fluorescent endocytosis marker FM1-43, and insulin-dependent membrane translocation of the glucose transporter GluT4. Similar effects could be observed for an antiserum raised directly to Snap23, whereas a serum to Snap25 failed to do so. In conclusion, Snap23 seems to be a possible immune target for anti-gonococcal antibodies, the interactions of which seem at least in vitro to interfere with vesicle-associated exocytosis. Whether these changes contribute to the correlation between maternal gonococcal infections and psychosis in vivo remains still to be clarified.
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Morales PE, Bucarey JL, Espinosa A. Muscle Lipid Metabolism: Role of Lipid Droplets and Perilipins. J Diabetes Res 2017; 2017:1789395. [PMID: 28676863 PMCID: PMC5476901 DOI: 10.1155/2017/1789395] [Citation(s) in RCA: 106] [Impact Index Per Article: 15.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/06/2017] [Revised: 04/19/2017] [Accepted: 04/26/2017] [Indexed: 02/07/2023] Open
Abstract
Skeletal muscle is one of the main regulators of carbohydrate and lipid metabolism in our organism, and therefore, it is highly susceptible to changes in glucose and fatty acid (FA) availability. Skeletal muscle is an extremely complex tissue: its metabolic capacity depends on the type of fibers it is made up of and the level of stimulation it undergoes, such as acute or chronic contraction. Obesity is often associated with increased FA levels, which leads to the accumulation of toxic lipid intermediates, oxidative stress, and autophagy in skeletal fibers. This lipotoxicity is one of the most common causes of insulin resistance (IR). In this scenario, the "isolation" of certain lipids in specific cell compartments, through the action of the specific lipid droplet, perilipin (PLIN) family of proteins, is conceived as a lifeguard compensatory strategy. In this review, we summarize the cellular mechanism underlying lipid mobilization and metabolism inside skeletal muscle, focusing on the function of lipid droplets, the PLIN family of proteins, and how these entities are modified in exercise, obesity, and IR conditions.
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Affiliation(s)
- Pablo Esteban Morales
- Departamento de Tecnología Médica, Facultad de Medicina, Universidad de Chile, Santiago, Chile
| | - Jose Luis Bucarey
- CIDIS-AC, Escuela de Medicina, Universidad de Valparaiso, Valparaiso, Chile
| | - Alejandra Espinosa
- Departamento de Tecnología Médica, Facultad de Medicina, Universidad de Chile, Santiago, Chile
- Center for Molecular Studies of the Cell, Facultad de Medicina, Universidad de Chile, Santiago, Chile
- *Alejandra Espinosa:
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Strauss JA, Shaw CS, Bradley H, Wilson OJ, Dorval T, Pilling J, Wagenmakers AJM. Immunofluorescence microscopy of SNAP23 in human skeletal muscle reveals colocalization with plasma membrane, lipid droplets, and mitochondria. Physiol Rep 2016; 4:e12662. [PMID: 26733245 PMCID: PMC4760398 DOI: 10.14814/phy2.12662] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2015] [Revised: 11/27/2015] [Accepted: 11/30/2015] [Indexed: 11/24/2022] Open
Abstract
Synaptosomal-associated protein 23 (SNAP23) is a SNARE protein expressed abundantly in human skeletal muscle. Its established role is to mediate insulin-stimulated docking and fusion of glucose transporter 4 (GLUT4) with the plasma membrane. Recent in vitro research has proposed that SNAP23 may also play a role in the fusion of growing lipid droplets (LDs) and the channeling of LD-derived fatty acids (FAs) into neighboring mitochondria for β-oxidation. This study investigates the subcellular distribution of SNAP23 in human skeletal muscle using immunofluorescence microscopy to confirm that SNAP23 localization supports the three proposed metabolic roles. Percutaneous biopsies were obtained from the m. vastus lateralis of six lean, healthy males in the rested, overnight fasted state. Cryosections were stained with antibodies targeting SNAP23, the mitochondrial marker cytochrome c oxidase and the plasma membrane marker dystrophin, whereas intramuscular LDs were stained using the neutral lipid dye oil red O. SNAP23 displayed areas of intense punctate staining in the intracellular regions of all muscle fibers and continuous intense staining in peripheral regions of the cell. Quantitation of confocal microscopy images showed colocalization of SNAP23 with the plasma membrane marker dystrophin (Pearson's correlation coefficient r = 0.50 ± 0.01). The intense punctate intracellular staining colocalized primarily with the mitochondrial marker cytochrome C oxidase (r = 0.50 ± 0.012) and to a lesser extent with LDs (r = 0.21 ± 0.01) visualized with oil red O. We conclude that the observed subcellular distribution of SNAP23 in human skeletal muscle supports the three aforementioned metabolic roles.
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Affiliation(s)
- Juliette A Strauss
- Research Institute for Sport and Exercise Sciences, Liverpool John Moores University, Liverpool, UK
| | - Christopher S Shaw
- Centre for Physical Activity and Nutrition Research, School of Exercise and Nutrition Sciences, Deakin University, Geelong, Victoria, Australia
| | - Helen Bradley
- School of Sport, Exercise and Rehabilitation Sciences, University of Birmingham, Edgbaston, UK
| | - Oliver J Wilson
- Institute for Sport, Physical Activity and Leisure, Carnegie Faculty, Leeds Beckett University, Leeds, UK
| | | | | | - Anton J M Wagenmakers
- Research Institute for Sport and Exercise Sciences, Liverpool John Moores University, Liverpool, UK
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