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Wilhelmsen A, Stephens FB, Bennett AJ, Karagounis LG, Jones SW, Tsintzas K. Skeletal muscle myostatin mRNA expression is upregulated in aged human adults with excess adiposity but is not associated with insulin resistance and ageing. GeroScience 2024; 46:2033-2049. [PMID: 37801203 PMCID: PMC10828472 DOI: 10.1007/s11357-023-00956-6] [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: 06/19/2023] [Accepted: 09/20/2023] [Indexed: 10/07/2023] Open
Abstract
Myostatin negatively regulates skeletal muscle growth and appears upregulated in human obesity and associated with insulin resistance. However, observations are confounded by ageing, and the mechanisms responsible are unknown. The aim of this study was to delineate between the effects of excess adiposity, insulin resistance and ageing on myostatin mRNA expression in human skeletal muscle and to investigate causative factors using in vitro models. An in vivo cross-sectional analysis of human skeletal muscle was undertaken to isolate effects of excess adiposity and ageing per se on myostatin expression. In vitro studies employed human primary myotubes to investigate the potential involvement of cross-talk between subcutaneous adipose tissue (SAT) and skeletal muscle, and lipid-induced insulin resistance. Skeletal muscle myostatin mRNA expression was greater in aged adults with excess adiposity than age-matched adults with normal adiposity (2.0-fold higher; P < 0.05) and occurred concurrently with altered expression of genes involved in the maintenance of muscle mass but did not differ between younger and aged adults with normal adiposity. Neither chronic exposure to obese SAT secretome nor acute elevation of fatty acid availability (which induced insulin resistance) replicated the obesity-mediated upregulation of myostatin mRNA expression in vitro. In conclusion, skeletal muscle myostatin mRNA expression is uniquely upregulated in aged adults with excess adiposity and insulin resistance but not by ageing alone. This does not appear to be mediated by the SAT secretome or by lipid-induced insulin resistance. Thus, factors intrinsic to skeletal muscle may be responsible for the obesity-mediated upregulation of myostatin, and future work to establish causality is required.
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Affiliation(s)
- Andrew Wilhelmsen
- MRC Versus Arthritis Centre for Musculoskeletal Ageing Research, School of Life Sciences, University of Nottingham, Queen's Medical Centre, Nottingham, NG7 2UH, UK
| | | | - Andrew J Bennett
- School of Life Sciences, University of Nottingham, Queen's Medical Centre, Nottingham, UK
| | - Leonidas G Karagounis
- Mary MacKillop Institute for Health Research (MMIHR), Melbourne, Australian Catholic University, Melbourne, Australia
- Institute of Social and Preventive Medicine (ISPM), University of Bern, Bern, Switzerland
| | - Simon W Jones
- Institute of Inflammation and Ageing, MRC Versus Arthritis Centre for Musculoskeletal Ageing Research, Queen Elizabeth Hospital, The University of Birmingham, Birmingham, UK
| | - Kostas Tsintzas
- MRC Versus Arthritis Centre for Musculoskeletal Ageing Research, School of Life Sciences, University of Nottingham, Queen's Medical Centre, Nottingham, NG7 2UH, UK.
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Skeletal-Muscle-Specific Overexpression of Chrono Leads to Disruption of Glucose Metabolism and Exercise Capacity. LIFE (BASEL, SWITZERLAND) 2022; 12:life12081233. [PMID: 36013411 PMCID: PMC9410257 DOI: 10.3390/life12081233] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/20/2022] [Revised: 08/07/2022] [Accepted: 08/09/2022] [Indexed: 11/17/2022]
Abstract
Disruption of circadian rhythms is related to disorders of glucose metabolism, and the molecular clock also exists in skeletal muscle. The ChIP-derived repressor of network oscillator (Chrono) and brain and muscle ARNT-like 1 (Bmal1) are core circadian components. Chrono is considered to be the repressor of Bmal1, and the Chrono–Bmal1 pathway is important in regulating the circadian rhythm; it has been speculated that this pathway could be a new mechanism for regulating glucose metabolism. The purpose of this study was to investigate the effects of Chrono on glucose metabolism in skeletal muscle and exercise capacity by using mice with skeletal-muscle-specific overexpression of Chrono (Chrono TG) and wild-type (WT) mice as the animal models. The results of this cross-sectional study indicated that the Chrono TG mice had an impaired glucose tolerance, lower exercise capacity, and higher levels of nonfasted blood glucose and glycogen content in skeletal muscle compared to WT mice. In addition, the Chrono TG mice also showed a significant increase in the amount of Chrono bound to Bmal1 according to a co-IP analysis; a remarkable decrease in mRNA expression of Tbc1d1, Glut4, Hk2, Pfkm, Pdp1, Gbe1, and Phka1, as well as in activity of Hk and protein expression of Ldhb; but higher mRNA expression of Pdk4 and protein expression of Ldha compared with those of WT mice. These data suggested the skeletal-muscle-specific overexpression of Chrono led to a greater amount of Chrono bound to Bmal1, which then could affect the glucose transporter, glucose oxidation, and glycogen utilization in skeletal muscle, as well as exercise capacity.
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Thomas SS, Wu J, Davogustto G, Holliday MW, Eckel-Mahan K, Verzola D, Garibotto G, Hu Z, Mitch WE, Taegtmeyer H. SIRPα Mediates IGF1 Receptor in Cardiomyopathy Induced by Chronic Kidney Disease. Circ Res 2022; 131:207-221. [PMID: 35722884 PMCID: PMC10010047 DOI: 10.1161/circresaha.121.320546] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND Chronic kidney disease (CKD) is characterized by increased myocardial mass despite near-normal blood pressure, suggesting the presence of a separate trigger. A potential driver is SIRPα (signal regulatory protein alpha)-a mediator impairing insulin signaling. The objective of this study is to assess the role of circulating SIRPα in CKD-induced adverse cardiac remodeling. METHODS SIRPα expression was evaluated in mouse models and patients with CKD. Specifically, mutant, muscle-specific, or cardiac muscle-specific SIRPα KO (knockout) mice were examined after subtotal nephrectomy. Cardiac function was assessed by echocardiography. Metabolic responses were confirmed in cultured muscle cells or cardiomyocytes. RESULTS We demonstrate that SIRPα regulates myocardial insulin/IGF1R (insulin growth factor-1 receptor) signaling in CKD. First, in the serum of both mice and patients, SIRPα was robustly secreted in response to CKD. Second, cardiac muscle upregulation of SIRPα was associated with impaired insulin/IGF1R signaling, myocardial dysfunction, and fibrosis. However, both global and cardiac muscle-specific SIRPα KO mice displayed improved cardiac function when compared with control mice with CKD. Third, both muscle-specific or cardiac muscle-specific SIRPα KO mice did not significantly activate fetal genes and maintained insulin/IGF1R signaling with suppressed fibrosis despite the presence of CKD. Importantly, SIRPα directly interacted with IGF1R. Next, rSIRPα (recombinant SIRPα) protein was introduced into muscle-specific SIRPα KO mice reestablishing the insulin/IGF1R signaling activity. Additionally, overexpression of SIRPα in myoblasts and cardiomyocytes impaired pAKT (phosphorylation of AKT) and insulin/IGF1R signaling. Furthermore, myotubes and cardiomyocytes, but not adipocytes treated with high glucose or cardiomyocytes treated with uremic toxins, stimulated secretion of SIRPα in culture media, suggesting these cells are the origin of circulating SIRPα in CKD. Both intracellular and extracellular SIRPα exert biologically synergistic effects impairing intracellular myocardial insulin/IGF1R signaling. CONCLUSIONS Myokine SIRPα expression impairs insulin/IGF1R functions in cardiac muscle, affecting cardiometabolic signaling pathways. Circulating SIRPα constitutes an important readout of insulin resistance in CKD-induced cardiomyopathy.
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Affiliation(s)
- Sandhya S Thomas
- Nephrology Division, Department of Medicine, Michael E. Debakey VA Medical Center, Houston, TX (S.S.T.).,Nephrology Division, Department of Medicine, Baylor College of Medicine, Houston, TX (S.S.T., J.W., M.W.H., Z.H., W.E.M.)
| | - Jiao Wu
- Nephrology Division, Department of Medicine, Baylor College of Medicine, Houston, TX (S.S.T., J.W., M.W.H., Z.H., W.E.M.)
| | - Giovanni Davogustto
- Cardiology Division, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN (G.D.)
| | - Michael W Holliday
- Nephrology Division, Department of Medicine, Baylor College of Medicine, Houston, TX (S.S.T., J.W., M.W.H., Z.H., W.E.M.)
| | - Kristin Eckel-Mahan
- Center for Metabolic and Degenerative Diseases, Institute of Molecular Medicine, The University of Texas Health Science Center, Houston (K.E.-M.)
| | - Daniela Verzola
- Nephrology Division, Department of Medicine, Università degli Studi di Genova, Genoa, Italy (D.V., G.G.)
| | - Giacomo Garibotto
- Nephrology Division, Department of Medicine, Università degli Studi di Genova, Genoa, Italy (D.V., G.G.)
| | - Zhaoyong Hu
- Nephrology Division, Department of Medicine, Baylor College of Medicine, Houston, TX (S.S.T., J.W., M.W.H., Z.H., W.E.M.)
| | - William E Mitch
- Nephrology Division, Department of Medicine, Baylor College of Medicine, Houston, TX (S.S.T., J.W., M.W.H., Z.H., W.E.M.)
| | - Heinrich Taegtmeyer
- Cardiology Division, Department of Medicine, McGovern Medical School at the University of Texas Health Science Center, Houston (H.T.)
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Perry CA, Van Guilder GP, Butterick TA. Decreased myostatin in response to a controlled DASH diet is associated with improved body composition and cardiometabolic biomarkers in older adults: results from a controlled-feeding diet intervention study. BMC Nutr 2022; 8:24. [PMID: 35287731 PMCID: PMC8922920 DOI: 10.1186/s40795-022-00516-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2021] [Accepted: 03/01/2022] [Indexed: 12/25/2022] Open
Abstract
BACKGROUND Elevated concentrations of myostatin inhibit muscle growth, function and strength. Myostatin is a mediator of sarcopenia and is associated with insulin resistance. For this study we tested the response of a calorie-restricted Dietary Approaches to Stop Hypertension (DASH) diet on changes in myostatin, follistatin, and mystatin:follistatin ratio levels after 12 weeks in comparison to basline in adults aged 65 years and older. Furthermore we evaluated correlations between changes in myostatin, body composition and cardiometabolic biomarkers in this cohort of older adults. METHODS This was a controlled-feeding diet intervention study in which females (n = 17) and males (n = 11) aged 65 years and older consumed either 85 g (n = 15) or 170 g (n = 13) of fresh lean beef within a standardized DASH diet for 12-weeks. Myostatin and follistatin concentrations were measured from fasted blood samples collected at 5 timepoints throughout the 12-week feeding intervention period. Correlations were assessed between changes in myostatin and follistatin levels and measures of body composition and cardiometabolic biomarkers. RESULTS There were no differences (p > 0.05) in circulating myostatin or follistatin levels between the beef intake groups. However, with beef groups combined myostatin decreased by 17.6% (p = 0.006) and the myostatin-to-follistatin ratio decreased by 16.5% (p < 0.001) in response to the study diet. Decreased myostatin was positively correlated with reductions in waist circumference (R2 = 0.163; p = 0.033) and fat mass (R2 = 0.233; p = 0.009). There was an inverse relationship between decreased myostatin and increased strength-to-weight ratio (R2 = 0.162; p = 0.034). The change in myostatin-to-follistatin ratio was associated with the change in skeletal muscle mass-to-fat mass ratio (R2 = 0.176; p = 0.026). Decreased myostatin was positively correlated with reductions in total cholesterol (R2 = 0.193; p = 0.012), LDL-C (R2 = 0.163; p = 0.031), insulin (R2 = 0.234; p = 0.009), and HOMA-IR (R2 = 0.248; P = 0.007). There was no change (p > 0.05) in circulating follistatin concentrations in response to the diet intervention. CONCLUSIONS The outcomes from this study suggest that a calorie-restricted DASH diet has the potential to reduce myostatin concentrations in older adults. Furthermore these outcomes support interrelationships between myostatin, body composition and cardiometabolic health in adults aged 65 years and older. TRIAL REGISTRATION ClinicalTrials.gov; Identifier: NCT04127240 ; Registration Date: 15/10/ 2019.
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Affiliation(s)
- Cydne A. Perry
- grid.411377.70000 0001 0790 959XDepartment of Applied Health Science, Indiana University School of Public Health, 1025 Seventh St., Bloomington, IN 47405 USA
| | - Gary P. Van Guilder
- Exercise and Sport Science Department, Western Colorado University, Gunnison, CO 81230 USA
| | - Tammy A. Butterick
- grid.410394.b0000 0004 0419 8667Department of Veterans Affairs, Research Service, Minneapolis VA Health Care System, Minneapolis, MN 55417 USA ,grid.17635.360000000419368657Department of Neuroscinece, University of Minnesota, Minneapolis, MN 55455 USA ,grid.17635.360000000419368657Department of Food Science and Nutrition, University of Minnesota, St. Paul, MN 55108 USA
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Bilski J, Pierzchalski P, Szczepanik M, Bonior J, Zoladz JA. Multifactorial Mechanism of Sarcopenia and Sarcopenic Obesity. Role of Physical Exercise, Microbiota and Myokines. Cells 2022; 11:cells11010160. [PMID: 35011721 PMCID: PMC8750433 DOI: 10.3390/cells11010160] [Citation(s) in RCA: 52] [Impact Index Per Article: 26.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Revised: 12/27/2021] [Accepted: 12/31/2021] [Indexed: 02/07/2023] Open
Abstract
Obesity and ageing place a tremendous strain on the global healthcare system. Age-related sarcopenia is characterized by decreased muscular strength, decreased muscle quantity, quality, and decreased functional performance. Sarcopenic obesity (SO) is a condition that combines sarcopenia and obesity and has a substantial influence on the older adults’ health. Because of the complicated pathophysiology, there are disagreements and challenges in identifying and diagnosing SO. Recently, it has become clear that dysbiosis may play a role in the onset and progression of sarcopenia and SO. Skeletal muscle secretes myokines during contraction, which play an important role in controlling muscle growth, function, and metabolic balance. Myokine dysfunction can cause and aggravate obesity, sarcopenia, and SO. The only ways to prevent and slow the progression of sarcopenia, particularly sarcopenic obesity, are physical activity and correct nutritional support. While exercise cannot completely prevent sarcopenia and age-related loss in muscular function, it can certainly delay development and slow down the rate of sarcopenia. The purpose of this review was to discuss potential pathways to muscle deterioration in obese individuals. We also want to present the current understanding of the role of various factors, including microbiota and myokines, in the process of sarcopenia and SO.
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Affiliation(s)
- Jan Bilski
- Department of Biomechanics and Kinesiology, Chair of Biomedical Sciences, Faculty of Health Sciences, Institute of Physiotherapy, Jagiellonian University Medical College, 31-008 Krakow, Poland
- Correspondence: ; Tel.: +48-12-421-93-51
| | - Piotr Pierzchalski
- Department of Medical Physiology, Chair of Biomedical Sciences, Faculty of Health Sciences, Institute of Physiotherapy, Jagiellonian University Medical College, 31-126 Krakow, Poland; (P.P.); (J.B.)
| | - Marian Szczepanik
- Department of Medical Biology, Chair of Biomedical Sciences, Faculty of Health Sciences, Institute of Physiotherapy, Jagiellonian University Medical College, 31-034 Krakow, Poland;
| | - Joanna Bonior
- Department of Medical Physiology, Chair of Biomedical Sciences, Faculty of Health Sciences, Institute of Physiotherapy, Jagiellonian University Medical College, 31-126 Krakow, Poland; (P.P.); (J.B.)
| | - Jerzy A. Zoladz
- Chair of Exercise Physiology and Muscle Bioenergetics, Faculty of Health Sciences, Jagiellonian University Medical College, 31-066 Krakow, Poland;
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Zheng X, Zheng Y, Qin D, Yao Y, Zhang X, Zhao Y, Zheng C. Regulatory Role and Potential Importance of GDF-8 in Ovarian Reproductive Activity. Front Endocrinol (Lausanne) 2022; 13:878069. [PMID: 35692411 PMCID: PMC9178251 DOI: 10.3389/fendo.2022.878069] [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: 02/17/2022] [Accepted: 04/15/2022] [Indexed: 11/13/2022] Open
Abstract
Growth differentiation factor-8 (GDF-8) is a member of the transforming growth factor-beta superfamily. Studies in vitro and in vivo have shown GDF-8 to be involved in the physiology and pathology of ovarian reproductive functions. In vitro experiments using a granulosa-cell model have demonstrated steroidogenesis, gonadotrophin responsiveness, glucose metabolism, cell proliferation as well as expression of lysyl oxidase and pentraxin 3 to be regulated by GDF-8 via the mothers against decapentaplegic homolog signaling pathway. Clinical data have shown that GDF-8 is expressed widely in the human ovary and has high expression in serum of obese women with polycystic ovary syndrome. GDF-8 expression in serum changes dynamically in patients undergoing controlled ovarian hyperstimulation. GDF-8 expression in serum and follicular fluid is correlated with the ovarian response and pregnancy outcome during in vitro fertilization. Blocking the GDF-8 signaling pathway is a potential therapeutic for ovarian hyperstimulation syndrome and ovulation disorders in polycystic ovary syndrome. GDF-8 has a regulatory role and potential importance in ovarian reproductive activity and may be involved in folliculogenesis, ovulation, and early embryo implantation.
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Affiliation(s)
- Xiaoling Zheng
- Department of Pharmacy, Women’s Hospital, School of Medicine, Zhejiang University, Hangzhou, China
| | - Yongquan Zheng
- Department of Pharmacy, Women’s Hospital, School of Medicine, Zhejiang University, Hangzhou, China
| | - Dongxu Qin
- Department of Pharmacy, Women’s Hospital, School of Medicine, Zhejiang University, Hangzhou, China
| | - Yao Yao
- Department of Pharmacy, Women’s Hospital, School of Medicine, Zhejiang University, Hangzhou, China
| | - Xiao Zhang
- Department of Pharmacy, Women’s Hospital, School of Medicine, Zhejiang University, Hangzhou, China
| | - Yunchun Zhao
- Department of Pharmacy, Women’s Hospital, School of Medicine, Zhejiang University, Hangzhou, China
- *Correspondence: Caihong Zheng, ; Yunchun Zhao,
| | - Caihong Zheng
- Department of Pharmacy, Women’s Hospital, School of Medicine, Zhejiang University, Hangzhou, China
- Key Laboratory of Reproductive Genetics (Ministry of Education) and Women’s Reproductive Health Laboratory of Zhejiang Province, Women’s Hospital, Zhejiang University School of Medicine, Hangzhou, China
- *Correspondence: Caihong Zheng, ; Yunchun Zhao,
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Prokopidis K, Giannos P, Witard OC, Peckham D, Ispoglou T. Aberrant mitochondrial homeostasis at the crossroad of musculoskeletal ageing and non-small cell lung cancer. PLoS One 2022; 17:e0273766. [PMID: 36067173 PMCID: PMC9447904 DOI: 10.1371/journal.pone.0273766] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2022] [Accepted: 08/12/2022] [Indexed: 11/19/2022] Open
Abstract
Cancer cachexia is accompanied by muscle atrophy, sharing multiple common catabolic pathways with sarcopenia, including mitochondrial dysfunction. This study investigated gene expression from skeletal muscle tissues of older healthy adults, who are at risk of age-related sarcopenia, to identify potential gene biomarkers whose dysregulated expression and protein interference were involved in non-small cell lung cancer (NSCLC). Screening of the literature resulted in 14 microarray datasets (GSE25941, GSE28392, GSE28422, GSE47881, GSE47969, GSE59880 in musculoskeletal ageing; GSE118370, GSE33532, GSE19804, GSE18842, GSE27262, GSE19188, GSE31210, GSE40791 in NSCLC). Differentially expressed genes (DEGs) were used to construct protein-protein interaction networks and retrieve clustering gene modules. Overlapping module DEGs were ranked based on 11 topological algorithms and were correlated with prognosis, tissue expression, and tumour purity in NSCLC. The analysis revealed that the dysregulated expression of the mammalian mitochondrial ribosomal proteins, Mitochondrial Ribosomal Protein S26 (MRPS26), Mitochondrial Ribosomal Protein S17 (MRPS17), Mitochondrial Ribosomal Protein L18 (MRPL18) and Mitochondrial Ribosomal Protein L51 (MRPL51) were linked to reduced survival and tumour purity in NSCLC while tissue expression of the same genes followed an opposite direction in healthy older adults. These results support a potential link between the mitochondrial ribosomal microenvironment in ageing muscle and NSCLC. Further studies comparing changes in sarcopenia and NSCLC associated cachexia are warranted.
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Affiliation(s)
- Konstantinos Prokopidis
- Society of Meta-Research and Biomedical Innovation, London, United Kingdom
- Department of Musculoskeletal Biology, Institute of Life Course and Medical Sciences, University of Liverpool, Liverpool, United Kingdom
| | - Panagiotis Giannos
- Society of Meta-Research and Biomedical Innovation, London, United Kingdom
- Department of Life Sciences, Faculty of Natural Sciences, Imperial College London, London, United Kingdom
- * E-mail:
| | - Oliver C. Witard
- Faculty of Life Sciences and Medicine, Centre for Human and Applied Physiological Sciences, King’s College London, London, United Kingdom
| | - Daniel Peckham
- Leeds Institute of Medical Research at St James’s, University of Leeds, Leeds, United Kingdom
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Chen LK. The vicious cycle in the development of diabetes mellitus and sarcopenia in older persons. Arch Gerontol Geriatr 2021; 95:104437. [PMID: 34029928 DOI: 10.1016/j.archger.2021.104437] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- Liang-Kung Chen
- Aging and Health Research Center, National Yang Ming University, Taipei, Taiwan; Center for Geriatrics and Gerontology, Taipei Veterans General Hospital, Taipei, Taiwan; Taipei Municipal Gan-Dau Hospital, Taipei, Taiwan.
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Eilers W, Cleasby M, Foster K. Development of antisense-mediated myostatin knockdown for the treatment of insulin resistance. Sci Rep 2021; 11:1604. [PMID: 33452345 PMCID: PMC7810755 DOI: 10.1038/s41598-021-81222-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2020] [Accepted: 12/23/2020] [Indexed: 12/27/2022] Open
Abstract
Myostatin is a negative regulator of muscle mass and its inhibition represents a promising strategy for the treatment of muscle disorders and type 2 diabetes. However, there is currently no clinically effective myostatin inhibitor, and therefore novel methods are required. We evaluated the use of antisense phosphorodiamidate morpholino oligomers (PMO) to reduce myostatin expression in skeletal muscle and measured their effects on muscle mass and glucose uptake. C57/Bl6 mice received intramuscular or intravenous injections of anti-myostatin PMOs. Repeated intramuscular administration lead to a reduction in myostatin transcript levels (~ 20–40%), and an increase in muscle mass in chow and high-fat diet (HFD)-fed mice, but insulin-stimulated glucose uptake was reduced in PMO-treated muscles of HFD-fed mice. Five weekly intravenous administrations of 100 nmol PMO did not reduce myostatin expression, and therefore had no significant physiological effects. Unexpectedly, exon skipping levels were higher after intramuscular administration of PMO in HFD- than chow-fed mice. These results suggest that a modest PMO-induced reduction in myostatin transcript levels is sufficient to induce an increase in muscle mass, but that a greater degree of inhibition may be required to improve muscle glucose uptake.
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Affiliation(s)
- Wouter Eilers
- School of Biological Sciences, University of Reading, Reading, UK.
| | - Mark Cleasby
- Royal Veterinary College, University of London, London, UK
| | - Keith Foster
- School of Biological Sciences, University of Reading, Reading, UK
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