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Mebrahtu A, Smith IC, Liu S, Abusara Z, Leonard TR, Joumaa V, Herzog W. Reconsidering assumptions in the analysis of muscle fibre cross-sectional area. J Exp Biol 2024; 227:jeb248187. [PMID: 39319442 DOI: 10.1242/jeb.248187] [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: 06/14/2024] [Accepted: 09/09/2024] [Indexed: 09/26/2024]
Abstract
Cross-sectional area (CSA) is a fundamental variable in characterizing muscle mechanical properties. Typically, the CSA of a single muscle fibre is assessed by measuring either one or two diameters, and assuming the cross-section is either circular or elliptical in shape. However, fibre cross-sections have irregular shapes. The accuracy and precision of CSAs determined using circular and elliptical shape assumptions are unclear for mammalian skinned muscle fibres. Second harmonic generation imaging of skinned rabbit soleus fibres revealed that the circular assumption overstated real CSA by 5.3±25.9% whereas the elliptical assumption overstated real CSA by 2.8±6.9%. A preferred rotational alignment can bias the circular assumption, as real CSA was overstated by 22.1±24.8% when using the larger fibre diameter and understated by 11.4±13% when using the smaller fibre diameter. With 73% lower variable error and reduced bias, the elliptical assumption is superior to the circular assumption when assessing the CSA of skinned mammalian fibres.
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Affiliation(s)
- Abel Mebrahtu
- Human Performance Laboratory, Faculty of Kinesiology, University of Calgary, 2500 University Drive NW, Calgary, AB, Canada, T2N 1N4
| | - Ian C Smith
- Ottawa Hospital Research Institute, 1053 Carling Ave, Ottawa, ON, Canada, K1Y 4E9
| | - Shuyue Liu
- Human Performance Laboratory, Faculty of Kinesiology, University of Calgary, 2500 University Drive NW, Calgary, AB, Canada, T2N 1N4
| | - Ziad Abusara
- Human Performance Laboratory, Faculty of Kinesiology, University of Calgary, 2500 University Drive NW, Calgary, AB, Canada, T2N 1N4
| | - Timothy R Leonard
- Human Performance Laboratory, Faculty of Kinesiology, University of Calgary, 2500 University Drive NW, Calgary, AB, Canada, T2N 1N4
| | - Venus Joumaa
- Human Performance Laboratory, Faculty of Kinesiology, University of Calgary, 2500 University Drive NW, Calgary, AB, Canada, T2N 1N4
| | - Walter Herzog
- Human Performance Laboratory, Faculty of Kinesiology, University of Calgary, 2500 University Drive NW, Calgary, AB, Canada, T2N 1N4
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Buras ED, Woo MS, Kaul Verma R, Kondisetti SH, Davis CS, Claflin DR, Converso-Baran K, Michele DE, Brooks SV, Chun TH. Thrombospondin-1 promotes fibro-adipogenic stromal expansion and contractile dysfunction of the diaphragm in obesity. JCI Insight 2024; 9:e175047. [PMID: 38954467 PMCID: PMC11343600 DOI: 10.1172/jci.insight.175047] [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: 08/22/2023] [Accepted: 06/27/2024] [Indexed: 07/04/2024] Open
Abstract
Pulmonary disorders affect 40%-80% of individuals with obesity. Respiratory muscle dysfunction is linked to these conditions; however, its pathophysiology remains largely undefined. Mice subjected to diet-induced obesity (DIO) develop diaphragm muscle weakness. Increased intradiaphragmatic adiposity and extracellular matrix (ECM) content correlate with reductions in contractile force. Thrombospondin-1 (THBS1) is an obesity-associated matricellular protein linked with muscular damage in genetic myopathies. THBS1 induces proliferation of fibro-adipogenic progenitors (FAPs) - mesenchymal cells that differentiate into adipocytes and fibroblasts. We hypothesized that THBS1 drives FAP-mediated diaphragm remodeling and contractile dysfunction in DIO. We tested this by comparing the effects of dietary challenge on diaphragms of wild-type (WT) and Thbs1-knockout (Thbs1-/-) mice. Bulk and single-cell transcriptomics demonstrated DIO-induced stromal expansion in WT diaphragms. Diaphragm FAPs displayed upregulation of ECM and TGF-β-related expression signatures and augmentation of a Thy1-expressing subpopulation previously linked to type 2 diabetes. Despite similar weight gain, Thbs1-/- mice were protected from these transcriptomic changes and from obesity-induced increases in diaphragm adiposity and ECM deposition. Unlike WT controls, Thbs1-/- diaphragms maintained normal contractile force and motion after DIO challenge. THBS1 is therefore a necessary mediator of diaphragm stromal remodeling and contractile dysfunction in overnutrition and a potential therapeutic target in obesity-associated respiratory dysfunction.
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Affiliation(s)
- Eric D. Buras
- Division of Metabolism, Endocrinology and Diabetes (MEND), Department of Internal Medicine
| | - Moon-Sook Woo
- Division of Metabolism, Endocrinology and Diabetes (MEND), Department of Internal Medicine
| | - Romil Kaul Verma
- Division of Metabolism, Endocrinology and Diabetes (MEND), Department of Internal Medicine
| | | | | | - Dennis R. Claflin
- Department of Biomedical Engineering
- Department of Surgery, Section of Plastic Surgery
| | | | | | | | - Tae-Hwa Chun
- Division of Metabolism, Endocrinology and Diabetes (MEND), Department of Internal Medicine
- Biointerfaces Institute, University of Michigan, Ann Arbor, Michigan, USA
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3
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Crawford TO, Darras BT, Day JW, Dunaway Young S, Duong T, Nelson LL, Barrett D, Song G, Bilic S, Cote S, Sadanowicz M, Iarrobino R, Xu TJ, O'Neil J, Rossello J, Place A, Kertesz N, Nomikos G, Chyung Y. Safety and Efficacy of Apitegromab in Patients With Spinal Muscular Atrophy Types 2 and 3: The Phase 2 TOPAZ Study. Neurology 2024; 102:e209151. [PMID: 38330285 PMCID: PMC11067700 DOI: 10.1212/wnl.0000000000209151] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Accepted: 12/20/2023] [Indexed: 02/10/2024] Open
Abstract
BACKGROUND AND OBJECTIVES Currently approved therapies for spinal muscular atrophy (SMA) reverse the degenerative course, leading to better functional outcome, but they do not address the impairment arising from preexisting neurodegeneration. Apitegromab, an investigational, fully human monoclonal antibody, inhibits activation of myostatin (a negative regulator of skeletal muscle growth), thereby preserving muscle mass. The phase 2 TOPAZ trial assessed the safety and efficacy of apitegromab in individuals with later-onset type 2 and type 3 SMA. METHODS In this study, designed to investigate potential meaningful combinations of eligibility and treatment regimen for future studies, participants aged 2-21 years received IV apitegromab infusions every 4 weeks for 12 months in 1 of 3 cohorts. Cohort 1 stratified ambulatory participants aged 5-21 years into 2 arms (apitegromab 20 mg/kg alone or in combination with nusinersen); cohort 2 evaluated apitegromab 20 mg/kg combined with nusinersen in nonambulatory participants aged 5-21 years; and cohort 3 blindly evaluated 2 randomized apitegromab doses (2 and 20 mg/kg) combined with nusinersen in younger participants ≥2 years of age. The primary efficacy measure was mean change from baseline using the Hammersmith Functional Motor Scale version appropriate for each cohort. Data were analyzed using a paired t test with 2-sided 5% type 1 error for the mean change from baseline for predefined cohort-specific primary efficacy end points. RESULTS Fifty-eight participants (mean age 9.4 years) were enrolled at 16 trial sites in the United States and Europe. Participants had been treated with nusinersen for a mean of 25.9 months before enrollment in any of the 3 trial cohorts. At month 12, the mean change from baseline in Hammersmith scale score was -0.3 points (95% CI -2.1 to 1.4) in cohort 1 (n = 23), 0.6 points (-1.4 to 2.7) in cohort 2 (n = 15), and in cohort 3 (n = 20), the mean scores were 5.3 (-1.5 to 12.2) and 7.1 (1.8 to 12.5) for the 2-mg/kg (n = 8) and 20-mg/kg (n = 9) arms, respectively. The 5 most frequently reported treatment-emergent adverse events were headache (24.1%), pyrexia (22.4%), upper respiratory tract infection (22.4%), cough (22.4%), and nasopharyngitis (20.7%). No deaths or serious adverse reactions were reported. DISCUSSION Apitegromab led to improved motor function in participants with later-onset types 2 and 3 SMA. These results support a randomized, placebo-controlled phase 3 trial of apitegromab in participants with SMA. TRIAL REGISTRATION INFORMATION This trial is registered with ClinicalTrials.gov (NCT03921528). CLASSIFICATION OF EVIDENCE This study provides Class III evidence that apitegromab improves motor function in later-onset types 2 and 3 spinal muscular atrophy.
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Affiliation(s)
- Thomas O Crawford
- From the Department of Neurology (T.O.C.), Johns Hopkins University, Baltimore, MD; Department of Neurology (B.T.D.), Boston Children's Hospital, Harvard Medical School, MA; Department of Neurology (J.W.D., S.D.Y., T.D.), Stanford University, Palo Alto, CA; Department of Physical Therapy (L.L.N.), University of Texas Southwestern Medical Center, Dallas; Scholar Rock, Inc. (D.B., G.S., S.C., M.S., R.I., T.J.X., J.O.N., J.R., A.P., N.K., G.N., Y.C.), Cambridge, MA; Vanadro, LLC (S.B.), Urbandale, IA; Tourmaline Bio, Inc. (R.I.), New York, NY; Pfizer, Inc. (A.P.), New York, NY; Harmony Biosciences (G.N.), Plymouth Meeting, PA; and Stealth BioTherapeutics (Y.C.), Needham, MA
| | - Basil T Darras
- From the Department of Neurology (T.O.C.), Johns Hopkins University, Baltimore, MD; Department of Neurology (B.T.D.), Boston Children's Hospital, Harvard Medical School, MA; Department of Neurology (J.W.D., S.D.Y., T.D.), Stanford University, Palo Alto, CA; Department of Physical Therapy (L.L.N.), University of Texas Southwestern Medical Center, Dallas; Scholar Rock, Inc. (D.B., G.S., S.C., M.S., R.I., T.J.X., J.O.N., J.R., A.P., N.K., G.N., Y.C.), Cambridge, MA; Vanadro, LLC (S.B.), Urbandale, IA; Tourmaline Bio, Inc. (R.I.), New York, NY; Pfizer, Inc. (A.P.), New York, NY; Harmony Biosciences (G.N.), Plymouth Meeting, PA; and Stealth BioTherapeutics (Y.C.), Needham, MA
| | - John W Day
- From the Department of Neurology (T.O.C.), Johns Hopkins University, Baltimore, MD; Department of Neurology (B.T.D.), Boston Children's Hospital, Harvard Medical School, MA; Department of Neurology (J.W.D., S.D.Y., T.D.), Stanford University, Palo Alto, CA; Department of Physical Therapy (L.L.N.), University of Texas Southwestern Medical Center, Dallas; Scholar Rock, Inc. (D.B., G.S., S.C., M.S., R.I., T.J.X., J.O.N., J.R., A.P., N.K., G.N., Y.C.), Cambridge, MA; Vanadro, LLC (S.B.), Urbandale, IA; Tourmaline Bio, Inc. (R.I.), New York, NY; Pfizer, Inc. (A.P.), New York, NY; Harmony Biosciences (G.N.), Plymouth Meeting, PA; and Stealth BioTherapeutics (Y.C.), Needham, MA
| | - Sally Dunaway Young
- From the Department of Neurology (T.O.C.), Johns Hopkins University, Baltimore, MD; Department of Neurology (B.T.D.), Boston Children's Hospital, Harvard Medical School, MA; Department of Neurology (J.W.D., S.D.Y., T.D.), Stanford University, Palo Alto, CA; Department of Physical Therapy (L.L.N.), University of Texas Southwestern Medical Center, Dallas; Scholar Rock, Inc. (D.B., G.S., S.C., M.S., R.I., T.J.X., J.O.N., J.R., A.P., N.K., G.N., Y.C.), Cambridge, MA; Vanadro, LLC (S.B.), Urbandale, IA; Tourmaline Bio, Inc. (R.I.), New York, NY; Pfizer, Inc. (A.P.), New York, NY; Harmony Biosciences (G.N.), Plymouth Meeting, PA; and Stealth BioTherapeutics (Y.C.), Needham, MA
| | - Tina Duong
- From the Department of Neurology (T.O.C.), Johns Hopkins University, Baltimore, MD; Department of Neurology (B.T.D.), Boston Children's Hospital, Harvard Medical School, MA; Department of Neurology (J.W.D., S.D.Y., T.D.), Stanford University, Palo Alto, CA; Department of Physical Therapy (L.L.N.), University of Texas Southwestern Medical Center, Dallas; Scholar Rock, Inc. (D.B., G.S., S.C., M.S., R.I., T.J.X., J.O.N., J.R., A.P., N.K., G.N., Y.C.), Cambridge, MA; Vanadro, LLC (S.B.), Urbandale, IA; Tourmaline Bio, Inc. (R.I.), New York, NY; Pfizer, Inc. (A.P.), New York, NY; Harmony Biosciences (G.N.), Plymouth Meeting, PA; and Stealth BioTherapeutics (Y.C.), Needham, MA
| | - Leslie L Nelson
- From the Department of Neurology (T.O.C.), Johns Hopkins University, Baltimore, MD; Department of Neurology (B.T.D.), Boston Children's Hospital, Harvard Medical School, MA; Department of Neurology (J.W.D., S.D.Y., T.D.), Stanford University, Palo Alto, CA; Department of Physical Therapy (L.L.N.), University of Texas Southwestern Medical Center, Dallas; Scholar Rock, Inc. (D.B., G.S., S.C., M.S., R.I., T.J.X., J.O.N., J.R., A.P., N.K., G.N., Y.C.), Cambridge, MA; Vanadro, LLC (S.B.), Urbandale, IA; Tourmaline Bio, Inc. (R.I.), New York, NY; Pfizer, Inc. (A.P.), New York, NY; Harmony Biosciences (G.N.), Plymouth Meeting, PA; and Stealth BioTherapeutics (Y.C.), Needham, MA
| | - Doreen Barrett
- From the Department of Neurology (T.O.C.), Johns Hopkins University, Baltimore, MD; Department of Neurology (B.T.D.), Boston Children's Hospital, Harvard Medical School, MA; Department of Neurology (J.W.D., S.D.Y., T.D.), Stanford University, Palo Alto, CA; Department of Physical Therapy (L.L.N.), University of Texas Southwestern Medical Center, Dallas; Scholar Rock, Inc. (D.B., G.S., S.C., M.S., R.I., T.J.X., J.O.N., J.R., A.P., N.K., G.N., Y.C.), Cambridge, MA; Vanadro, LLC (S.B.), Urbandale, IA; Tourmaline Bio, Inc. (R.I.), New York, NY; Pfizer, Inc. (A.P.), New York, NY; Harmony Biosciences (G.N.), Plymouth Meeting, PA; and Stealth BioTherapeutics (Y.C.), Needham, MA
| | - Guochen Song
- From the Department of Neurology (T.O.C.), Johns Hopkins University, Baltimore, MD; Department of Neurology (B.T.D.), Boston Children's Hospital, Harvard Medical School, MA; Department of Neurology (J.W.D., S.D.Y., T.D.), Stanford University, Palo Alto, CA; Department of Physical Therapy (L.L.N.), University of Texas Southwestern Medical Center, Dallas; Scholar Rock, Inc. (D.B., G.S., S.C., M.S., R.I., T.J.X., J.O.N., J.R., A.P., N.K., G.N., Y.C.), Cambridge, MA; Vanadro, LLC (S.B.), Urbandale, IA; Tourmaline Bio, Inc. (R.I.), New York, NY; Pfizer, Inc. (A.P.), New York, NY; Harmony Biosciences (G.N.), Plymouth Meeting, PA; and Stealth BioTherapeutics (Y.C.), Needham, MA
| | - Sanela Bilic
- From the Department of Neurology (T.O.C.), Johns Hopkins University, Baltimore, MD; Department of Neurology (B.T.D.), Boston Children's Hospital, Harvard Medical School, MA; Department of Neurology (J.W.D., S.D.Y., T.D.), Stanford University, Palo Alto, CA; Department of Physical Therapy (L.L.N.), University of Texas Southwestern Medical Center, Dallas; Scholar Rock, Inc. (D.B., G.S., S.C., M.S., R.I., T.J.X., J.O.N., J.R., A.P., N.K., G.N., Y.C.), Cambridge, MA; Vanadro, LLC (S.B.), Urbandale, IA; Tourmaline Bio, Inc. (R.I.), New York, NY; Pfizer, Inc. (A.P.), New York, NY; Harmony Biosciences (G.N.), Plymouth Meeting, PA; and Stealth BioTherapeutics (Y.C.), Needham, MA
| | - Shaun Cote
- From the Department of Neurology (T.O.C.), Johns Hopkins University, Baltimore, MD; Department of Neurology (B.T.D.), Boston Children's Hospital, Harvard Medical School, MA; Department of Neurology (J.W.D., S.D.Y., T.D.), Stanford University, Palo Alto, CA; Department of Physical Therapy (L.L.N.), University of Texas Southwestern Medical Center, Dallas; Scholar Rock, Inc. (D.B., G.S., S.C., M.S., R.I., T.J.X., J.O.N., J.R., A.P., N.K., G.N., Y.C.), Cambridge, MA; Vanadro, LLC (S.B.), Urbandale, IA; Tourmaline Bio, Inc. (R.I.), New York, NY; Pfizer, Inc. (A.P.), New York, NY; Harmony Biosciences (G.N.), Plymouth Meeting, PA; and Stealth BioTherapeutics (Y.C.), Needham, MA
| | - Mara Sadanowicz
- From the Department of Neurology (T.O.C.), Johns Hopkins University, Baltimore, MD; Department of Neurology (B.T.D.), Boston Children's Hospital, Harvard Medical School, MA; Department of Neurology (J.W.D., S.D.Y., T.D.), Stanford University, Palo Alto, CA; Department of Physical Therapy (L.L.N.), University of Texas Southwestern Medical Center, Dallas; Scholar Rock, Inc. (D.B., G.S., S.C., M.S., R.I., T.J.X., J.O.N., J.R., A.P., N.K., G.N., Y.C.), Cambridge, MA; Vanadro, LLC (S.B.), Urbandale, IA; Tourmaline Bio, Inc. (R.I.), New York, NY; Pfizer, Inc. (A.P.), New York, NY; Harmony Biosciences (G.N.), Plymouth Meeting, PA; and Stealth BioTherapeutics (Y.C.), Needham, MA
| | - Ryan Iarrobino
- From the Department of Neurology (T.O.C.), Johns Hopkins University, Baltimore, MD; Department of Neurology (B.T.D.), Boston Children's Hospital, Harvard Medical School, MA; Department of Neurology (J.W.D., S.D.Y., T.D.), Stanford University, Palo Alto, CA; Department of Physical Therapy (L.L.N.), University of Texas Southwestern Medical Center, Dallas; Scholar Rock, Inc. (D.B., G.S., S.C., M.S., R.I., T.J.X., J.O.N., J.R., A.P., N.K., G.N., Y.C.), Cambridge, MA; Vanadro, LLC (S.B.), Urbandale, IA; Tourmaline Bio, Inc. (R.I.), New York, NY; Pfizer, Inc. (A.P.), New York, NY; Harmony Biosciences (G.N.), Plymouth Meeting, PA; and Stealth BioTherapeutics (Y.C.), Needham, MA
| | - Tiina J Xu
- From the Department of Neurology (T.O.C.), Johns Hopkins University, Baltimore, MD; Department of Neurology (B.T.D.), Boston Children's Hospital, Harvard Medical School, MA; Department of Neurology (J.W.D., S.D.Y., T.D.), Stanford University, Palo Alto, CA; Department of Physical Therapy (L.L.N.), University of Texas Southwestern Medical Center, Dallas; Scholar Rock, Inc. (D.B., G.S., S.C., M.S., R.I., T.J.X., J.O.N., J.R., A.P., N.K., G.N., Y.C.), Cambridge, MA; Vanadro, LLC (S.B.), Urbandale, IA; Tourmaline Bio, Inc. (R.I.), New York, NY; Pfizer, Inc. (A.P.), New York, NY; Harmony Biosciences (G.N.), Plymouth Meeting, PA; and Stealth BioTherapeutics (Y.C.), Needham, MA
| | - Janet O'Neil
- From the Department of Neurology (T.O.C.), Johns Hopkins University, Baltimore, MD; Department of Neurology (B.T.D.), Boston Children's Hospital, Harvard Medical School, MA; Department of Neurology (J.W.D., S.D.Y., T.D.), Stanford University, Palo Alto, CA; Department of Physical Therapy (L.L.N.), University of Texas Southwestern Medical Center, Dallas; Scholar Rock, Inc. (D.B., G.S., S.C., M.S., R.I., T.J.X., J.O.N., J.R., A.P., N.K., G.N., Y.C.), Cambridge, MA; Vanadro, LLC (S.B.), Urbandale, IA; Tourmaline Bio, Inc. (R.I.), New York, NY; Pfizer, Inc. (A.P.), New York, NY; Harmony Biosciences (G.N.), Plymouth Meeting, PA; and Stealth BioTherapeutics (Y.C.), Needham, MA
| | - José Rossello
- From the Department of Neurology (T.O.C.), Johns Hopkins University, Baltimore, MD; Department of Neurology (B.T.D.), Boston Children's Hospital, Harvard Medical School, MA; Department of Neurology (J.W.D., S.D.Y., T.D.), Stanford University, Palo Alto, CA; Department of Physical Therapy (L.L.N.), University of Texas Southwestern Medical Center, Dallas; Scholar Rock, Inc. (D.B., G.S., S.C., M.S., R.I., T.J.X., J.O.N., J.R., A.P., N.K., G.N., Y.C.), Cambridge, MA; Vanadro, LLC (S.B.), Urbandale, IA; Tourmaline Bio, Inc. (R.I.), New York, NY; Pfizer, Inc. (A.P.), New York, NY; Harmony Biosciences (G.N.), Plymouth Meeting, PA; and Stealth BioTherapeutics (Y.C.), Needham, MA
| | - Amy Place
- From the Department of Neurology (T.O.C.), Johns Hopkins University, Baltimore, MD; Department of Neurology (B.T.D.), Boston Children's Hospital, Harvard Medical School, MA; Department of Neurology (J.W.D., S.D.Y., T.D.), Stanford University, Palo Alto, CA; Department of Physical Therapy (L.L.N.), University of Texas Southwestern Medical Center, Dallas; Scholar Rock, Inc. (D.B., G.S., S.C., M.S., R.I., T.J.X., J.O.N., J.R., A.P., N.K., G.N., Y.C.), Cambridge, MA; Vanadro, LLC (S.B.), Urbandale, IA; Tourmaline Bio, Inc. (R.I.), New York, NY; Pfizer, Inc. (A.P.), New York, NY; Harmony Biosciences (G.N.), Plymouth Meeting, PA; and Stealth BioTherapeutics (Y.C.), Needham, MA
| | - Nathalie Kertesz
- From the Department of Neurology (T.O.C.), Johns Hopkins University, Baltimore, MD; Department of Neurology (B.T.D.), Boston Children's Hospital, Harvard Medical School, MA; Department of Neurology (J.W.D., S.D.Y., T.D.), Stanford University, Palo Alto, CA; Department of Physical Therapy (L.L.N.), University of Texas Southwestern Medical Center, Dallas; Scholar Rock, Inc. (D.B., G.S., S.C., M.S., R.I., T.J.X., J.O.N., J.R., A.P., N.K., G.N., Y.C.), Cambridge, MA; Vanadro, LLC (S.B.), Urbandale, IA; Tourmaline Bio, Inc. (R.I.), New York, NY; Pfizer, Inc. (A.P.), New York, NY; Harmony Biosciences (G.N.), Plymouth Meeting, PA; and Stealth BioTherapeutics (Y.C.), Needham, MA
| | - George Nomikos
- From the Department of Neurology (T.O.C.), Johns Hopkins University, Baltimore, MD; Department of Neurology (B.T.D.), Boston Children's Hospital, Harvard Medical School, MA; Department of Neurology (J.W.D., S.D.Y., T.D.), Stanford University, Palo Alto, CA; Department of Physical Therapy (L.L.N.), University of Texas Southwestern Medical Center, Dallas; Scholar Rock, Inc. (D.B., G.S., S.C., M.S., R.I., T.J.X., J.O.N., J.R., A.P., N.K., G.N., Y.C.), Cambridge, MA; Vanadro, LLC (S.B.), Urbandale, IA; Tourmaline Bio, Inc. (R.I.), New York, NY; Pfizer, Inc. (A.P.), New York, NY; Harmony Biosciences (G.N.), Plymouth Meeting, PA; and Stealth BioTherapeutics (Y.C.), Needham, MA
| | - Yung Chyung
- From the Department of Neurology (T.O.C.), Johns Hopkins University, Baltimore, MD; Department of Neurology (B.T.D.), Boston Children's Hospital, Harvard Medical School, MA; Department of Neurology (J.W.D., S.D.Y., T.D.), Stanford University, Palo Alto, CA; Department of Physical Therapy (L.L.N.), University of Texas Southwestern Medical Center, Dallas; Scholar Rock, Inc. (D.B., G.S., S.C., M.S., R.I., T.J.X., J.O.N., J.R., A.P., N.K., G.N., Y.C.), Cambridge, MA; Vanadro, LLC (S.B.), Urbandale, IA; Tourmaline Bio, Inc. (R.I.), New York, NY; Pfizer, Inc. (A.P.), New York, NY; Harmony Biosciences (G.N.), Plymouth Meeting, PA; and Stealth BioTherapeutics (Y.C.), Needham, MA
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Buras ED, Woo MS, Verma RK, Kondisetti SH, Davis CS, Claflin DR, Baran KC, Michele DE, Brooks SV, Chun TH. Thrombospondin-1 promotes fibro-adipogenic stromal expansion and contractile dysfunction of the diaphragm in obesity. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.08.17.553733. [PMID: 37645822 PMCID: PMC10462153 DOI: 10.1101/2023.08.17.553733] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/31/2023]
Abstract
Pulmonary disorders impact 40-80% of individuals with obesity. Respiratory muscle dysfunction is linked to these conditions; however, its pathophysiology remains largely undefined. Mice subjected to diet-induced obesity (DIO) develop diaphragmatic weakness. Increased intra-diaphragmatic adiposity and extracellular matrix (ECM) content correlate with reductions in contractile force. Thrombospondin-1 (THBS1) is an obesity-associated matricellular protein linked with muscular damage in genetic myopathies. THBS1 induces proliferation of fibro-adipogenic progenitors (FAPs)-mesenchymal cells that differentiate into adipocytes and fibroblasts. We hypothesized that THBS1 drives FAP-mediated diaphragm remodeling and contractile dysfunction in DIO. We tested this by comparing effects of dietary challenge on diaphragms of wild-type (WT) and Thbs1 knockout ( Thbs1 -/- ) mice. Bulk and single-cell transcriptomics demonstrated DIO-induced stromal expansion in WT diaphragms. Diaphragm FAPs displayed upregulation of ECM and TGFβ-related expression signatures, and augmentation of a Thy1 -expressing sub-population previously linked to type 2 diabetes. Despite similar weight gain, Thbs1 -/- mice were protected from these transcriptomic changes, and from obesity-induced increases in diaphragm adiposity and ECM deposition. Unlike WT controls, Thbs1 -/- diaphragms maintained normal contractile force and motion after DIO challenge. These findings establish THBS1 as a necessary mediator of diaphragm stromal remodeling and contractile dysfunction in overnutrition, and potential therapeutic target in obesity-associated respiratory dysfunction.
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Félix-Soriano E, Stanford KI. Exerkines and redox homeostasis. Redox Biol 2023; 63:102748. [PMID: 37247469 PMCID: PMC10236471 DOI: 10.1016/j.redox.2023.102748] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Revised: 05/12/2023] [Accepted: 05/12/2023] [Indexed: 05/31/2023] Open
Abstract
Exercise physiology has gained increasing interest due to its wide effects to promote health. Recent years have seen a growth in this research field also due to the finding of several circulating factors that mediate the effects of exercise. These factors, termed exerkines, are metabolites, growth factors, and cytokines secreted by main metabolic organs during exercise to regulate exercise systemic and tissue-specific effects. The metabolic effects of exerkines have been broadly explored and entail a promising target to modulate beneficial effects of exercise in health and disease. However, exerkines also have broad effects to modulate redox signaling and homeostasis in several cellular processes to improve stress response. Since redox biology is central to exercise physiology, this review summarizes current evidence for the cross-talk between redox biology and exerkines actions. The role of exerkines in redox biology entails a response to oxidative stress-induced pathological cues to improve health outcomes and to modulate exercise adaptations that integrate redox signaling.
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Affiliation(s)
- Elisa Félix-Soriano
- Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, OH, USA; Department of Physiology and Cell Biology, The Ohio State University College of Medicine, Columbus, OH, USA
| | - Kristin I Stanford
- Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, OH, USA; Department of Physiology and Cell Biology, The Ohio State University College of Medicine, Columbus, OH, USA; Department of Internal Medicine, The Ohio State University College of Medicine, Columbus, OH, USA.
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Sabouri M, Taghibeikzadehbadr P, Shabkhiz F, Izanloo Z, Shaghaghi FA. Effect of eccentric and concentric contraction mode on myogenic regulatory factors expression in human vastus lateralis muscle. J Muscle Res Cell Motil 2022; 43:9-20. [PMID: 35018575 DOI: 10.1007/s10974-021-09613-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2021] [Accepted: 12/01/2021] [Indexed: 11/26/2022]
Abstract
Skeletal muscle contractions are caused to release myokines by muscle fiber. This study investigated the myogenic regulatory factors, as MHC I, IIA, IIX, Myo-D, MRF4, Murf, Atrogin-1, Decorin, Myonection, and IL-15 mRNA expression in the response of eccentric vs concentric contraction. Eighteen healthy men were randomly divided into two eccentric and concentric groups, each of 9 persons. Isokinetic contraction protocols included maximal single-leg eccentric or concentric knee extension tasks at 60°/s with the dominant leg. Contractions consisted of a maximum of 12 sets of 10 reps, and the rest time between each set was 30 s. The baseline biopsy was performed 4 weeks before the study, and post-test biopsies were taken immediately after exercise protocols from the vastus lateralis muscle. The gene expression levels were evaluated using Real-Time PCR methods. The eccentric group showed a significantly lower RPE score than the concentric group (P ≤ 0.05). A significant difference in MyoD, MRF4, Myonection, and Decorin mRNA, were observed following eccentric or concentric contractions (P ≤ 0.05). The MHC I, MHC IIA, IL-15 mRNA has been changed significantly compared to the pre-exercise in the concentric group (P ≤ 0.05). While only MHC IIX and Atrogin-1 mRNA changed significantly in the eccentric group (P ≤ 0.05). Additionally, the results showed a significant difference in MyoD, MRF4, IL-15, and Decorin at the follow-up values between eccentric or concentric groups (P ≤ 0.05). Our findings highlight the growing importance of elucidating the different responses of muscle growth factors associated with a myogenic activity such as MHC IIA, Decorin, IL-15, Myonectin, Decorin, MuRF1, and MHC IIX mRNA in following various types of exercise.
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Affiliation(s)
- Mostafa Sabouri
- Department of Exercise Physiology & Health Science, University of Tehran, Tehran, Iran.
| | | | - Fatemeh Shabkhiz
- Department of Exercise Physiology & Health Science, University of Tehran, Tehran, Iran
| | - Zahra Izanloo
- Department of Sport Science, Faculty of Human Science, University of Bojnord, Bojnord, Iran
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7
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Iyer CC, Chugh D, Bobbili PJ, Iii AJB, Crum AE, Yi AF, Kaspar BK, Meyer KC, Burghes AHM, Arnold WD. Follistatin-induced muscle hypertrophy in aged mice improves neuromuscular junction innervation and function. Neurobiol Aging 2021; 104:32-41. [PMID: 33964607 PMCID: PMC8225567 DOI: 10.1016/j.neurobiolaging.2021.03.005] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2020] [Revised: 02/28/2021] [Accepted: 03/07/2021] [Indexed: 12/23/2022]
Abstract
Sarcopenia, or age-related loss of muscle mass and strength, is an important contributor to loss of physical function in older adults. The pathogenesis of sarcopenia is likely multifactorial, but recently the role of neurological degeneration, such as motor unit loss, has received increased attention. Here, we investigated the longitudinal effects of muscle hypertrophy (via overexpression of human follistatin, a myostatin antagonist) on neuromuscular integrity in C57BL/6J mice between the ages of 24 and 27 months. Following follistatin overexpression (delivered via self-complementary adeno-associated virus subtype 9 injection), muscle weight and torque production were significantly improved. Follistatin treatment resulted in improvements of neuromuscular junction innervation and transmission but had no impact on age-related losses of motor units. These studies demonstrate that follistatin overexpression-induced muscle hypertrophy not only increased muscle weight and torque production but also countered age-related degeneration at the neuromuscular junction in mice.
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Affiliation(s)
- Chitra C Iyer
- Department of Neurology, Neuromuscular Division, The Ohio State University Wexner Medical Center, Columbus, OH, USA
| | - Deepti Chugh
- Department of Neurology, Neuromuscular Division, The Ohio State University Wexner Medical Center, Columbus, OH, USA
| | - Prameela J Bobbili
- Department of Neurology, Neuromuscular Division, The Ohio State University Wexner Medical Center, Columbus, OH, USA
| | - Anton J Blatnik Iii
- Department of Biological Chemistry and Pharmacology, The Ohio State University Wexner Medical Center, Columbus, OH, USA
| | - Alexander E Crum
- Department of Neurology, Neuromuscular Division, The Ohio State University Wexner Medical Center, Columbus, OH, USA
| | - Allen F Yi
- The Ohio State University College of Medicine, Columbus, OH, USA
| | - Brian K Kaspar
- The Research Institute, Nationwide Children's Hospital, Columbus, OH, USA
| | - Kathrin C Meyer
- The Research Institute, Nationwide Children's Hospital, Columbus, OH, USA; Department of Pediatrics, The Ohio State University, Columbus, OH, USA
| | - Arthur H M Burghes
- Department of Biological Chemistry and Pharmacology, The Ohio State University Wexner Medical Center, Columbus, OH, USA
| | - W David Arnold
- Department of Neurology, Neuromuscular Division, The Ohio State University Wexner Medical Center, Columbus, OH, USA; Department of Physical Medicine and Rehabilitation, The Ohio State University Wexner Medical Center, Columbus, OH, USA; Department of Neuroscience, The Ohio State University Wexner Medical Center, Columbus, OH, USA; Department of Physiology and Cell Biology, The Ohio State University Wexner Medical Center, Columbus, OH, USA.
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8
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Van Pelt DW, Kharaz YA, Sarver DC, Eckhardt LR, Dzierzawski JT, Disser NP, Piacentini AN, Comerford E, McDonagh B, Mendias CL. Multiomics analysis of the mdx/mTR mouse model of Duchenne muscular dystrophy. Connect Tissue Res 2021; 62:24-39. [PMID: 32664808 DOI: 10.1080/03008207.2020.1791103] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
PURPOSE/AIM Duchenne muscular dystrophy (DMD) is a progressive neuromuscular disease characterized by extensive muscle weakness. Patients with DMD lack a functional dystrophin protein, which transmits force and organizes the cytoskeleton of skeletal muscle. Multiomic studies have been proposed as a way to obtain novel insight about disease processes from preclinical models, and we used this approach to study pathological changes in dystrophic muscles. MATERIALS AND METHODS We evaluated hindlimb muscles of male mdx/mTR mice, which lack a functional dystrophin protein and have deficits in satellite cell abundance and proliferative capacity. Wild type (WT) C57BL/6 J mice served as controls. Muscle fiber contractility was measured, along with changes in the transcriptome using RNA sequencing, and in the proteome, metabolome, and lipidome using mass spectrometry. RESULTS While mdx/mTR mice displayed gross pathological changes and continued cycles of degeneration and regeneration, we found no differences in permeabilized fiber contractility between strains. However, there were numerous changes in the transcriptome and proteome related to protein balance, contractile elements, extracellular matrix, and metabolism. There was only a 53% agreement in fold-change data between the proteome and transcriptome. Numerous changes in markers of skeletal muscle metabolism were observed, with dystrophic muscles exhibiting elevated glycolytic metabolites such as 6-phosphoglycerate, fructose-6-phosphate and glucose-6-phosphate, fructose bisphosphate, phosphorylated hexoses, and phosphoenolpyruvate. CONCLUSIONS These findings highlight the utility of multiomics in studying muscle disease, and provide additional insight into the pathological changes in dystrophic muscles that might help to indirectly guide evidence-based nutritional or exercise prescription in DMD patients.
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Affiliation(s)
- Douglas W Van Pelt
- Department of Rehabilitation Sciences, College of Health Sciences, University of Kentucky , Lexington, KY, USA
| | - Yalda A Kharaz
- Department of Musculoskeletal Biology, Institute of Ageing and Chronic Disease, University of Liverpool , Liverpool, UK
| | - Dylan C Sarver
- Department of Orthopaedic Surgery, University of Michigan Medical School , Ann Arbor, MI, USA
| | - Logan R Eckhardt
- Department of Orthopaedic Surgery, University of Michigan Medical School , Ann Arbor, MI, USA
| | - Justin T Dzierzawski
- Department of Orthopaedic Surgery, University of Michigan Medical School , Ann Arbor, MI, USA
| | | | - Alex N Piacentini
- Research Institute, Hospital for Special Surgery , New York, NY, USA
| | - Eithne Comerford
- Department of Musculoskeletal Biology, Institute of Ageing and Chronic Disease, University of Liverpool , Liverpool, UK
| | - Brian McDonagh
- Department of Physiology, School of Medicine, National University of Ireland , Galway, Ireland
| | - Christopher L Mendias
- Department of Orthopaedic Surgery, University of Michigan Medical School , Ann Arbor, MI, USA.,Research Institute, Hospital for Special Surgery , New York, NY, USA.,Department of Physiology & Biophysics, Weill Cornell Medical College , New York, NY, USA
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9
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Hendrickse PW, Krusnauskas R, Hodson-Tole E, Venckunas T, Degens H. Endurance exercise plus overload induces fatigue resistance and similar hypertrophy in mice irrespective of muscle mass. Exp Physiol 2020; 105:2110-2122. [PMID: 33140456 DOI: 10.1113/ep089096] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2020] [Accepted: 10/28/2020] [Indexed: 12/29/2022]
Abstract
NEW FINDINGS What is the central question of this study? Does combining endurance and hypertrophic stimuli blunt the adaptations to both modalities and is this effect greater in muscles with larger baseline fibre cross sectional area? What is the main finding and its importance? Endurance exercise and hypertrophic stimuli can be combined to increase fatigue resistance and fibre size without blunting either adaptation regardless of baseline fibre size. ABSTRACT Previous studies have demonstrated that fibre cross-sectional area (FCSA) is inversely related to oxidative capacity, which is thought to be determined by diffusion limitations of oxygen, ADP and ATP. Consequently, it is hypothesised that (1) when endurance training is combined with a hypertrophic stimulus the response to each will be blunted, and (2) muscles with a smaller FCSA will show a larger hypertrophic response than those with a large FCSA. To investigate this, we combined overload with endurance exercise in 12-month-old male mice from three different strains with different FCSA: Berlin High (BEH) (large fibres), C57BL/6J (C57) (normal-sized fibres) and Berlin Low (BEL) (small fibres). The right plantaris muscle was subjected to overload through denervation of synergists with the left muscle acting as an internal control. Half the animals trained 30 min per day for 6 weeks. The overload-induced hypertrophy was not blunted by endurance exercise, and the exercise-induced increase in fatigue resistance was not impaired by overload. All strains demonstrated similar absolute increases in FCSA, although the BEH mice with more fibres than the C57 mice demonstrated the largest increase in muscle mass and BEL mice with fewer fibres the smallest increase in muscle mass. This study suggests that endurance exercise and hypertrophic stimuli can be combined without attenuating adaptations to either modality, and that increases in FCSA are independent of baseline fibre size.
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Affiliation(s)
- Paul W Hendrickse
- Department of Life Sciences, Research Centre for Musculoskeletal Science & Sports Medicine, Manchester Metropolitan University, Manchester, UK.,Lithuanian Sports University, Kaunas, Lithuania
| | | | - Emma Hodson-Tole
- Department of Life Sciences, Research Centre for Musculoskeletal Science & Sports Medicine, Manchester Metropolitan University, Manchester, UK
| | | | - Hans Degens
- Department of Life Sciences, Research Centre for Musculoskeletal Science & Sports Medicine, Manchester Metropolitan University, Manchester, UK.,Lithuanian Sports University, Kaunas, Lithuania
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10
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Exercise as a Therapeutic Strategy for Sarcopenia in Heart Failure: Insights into Underlying Mechanisms. Cells 2020; 9:cells9102284. [PMID: 33066240 PMCID: PMC7602002 DOI: 10.3390/cells9102284] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2020] [Revised: 10/06/2020] [Accepted: 10/10/2020] [Indexed: 12/16/2022] Open
Abstract
Sarcopenia, a syndrome commonly seen in elderly populations, is often characterized by a gradual loss of skeletal muscle, leading to the decline of muscle strength and physical performance. Growing evidence suggests that the prevalence of sarcopenia increases in patients with heart failure (HF), which is a dominant pathogenesis in the aging heart. HF causes diverse metabolic complications that may result in sarcopenia. Therefore, sarcopenia may act as a strong predictor of frailty, disability, and mortality associated with HF. Currently, standard treatments for slowing muscle loss in patients with HF are not available. Therefore, here, we review the pathophysiological mechanisms underlying sarcopenia in HF as well as current knowledge regarding the beneficial effects of exercise on sarcopenia in HF and related mechanisms, including hormonal changes, myostatin, oxidative stress, inflammation, apoptosis, autophagy, the ubiquitin-proteasome system, and insulin resistance.
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11
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Redox modulation of muscle mass and function. Redox Biol 2020; 35:101531. [PMID: 32371010 PMCID: PMC7284907 DOI: 10.1016/j.redox.2020.101531] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2020] [Revised: 03/28/2020] [Accepted: 03/31/2020] [Indexed: 12/21/2022] Open
Abstract
Muscle mass and strength are very important for exercise performance. Training-induced musculoskeletal injuries usually require periods of complete immobilization to prevent any muscle contraction of the affected muscle groups. Disuse muscle wasting will likely affect every sport practitioner in his or her lifetime. Even short periods of disuse results in significant declines in muscle size, fiber cross sectional area, and strength. To understand the molecular signaling pathways involved in disuse muscle atrophy is of the utmost importance to develop more effective countermeasures in sport science research. We have divided our review in four different sections. In the first one we discuss the molecular mechanisms involved in muscle atrophy including the main protein synthesis and protein breakdown signaling pathways. In the second section of the review we deal with the main cellular, animal, and human atrophy models. The sources of reactive oxygen species in disuse muscle atrophy and the mechanism through which they regulate protein synthesis and proteolysis are reviewed in the third section of this review. The last section is devoted to the potential interventions to prevent muscle disuse atrophy with especial consideration to studies on which the levels of endogenous antioxidants enzymes or dietary antioxidants have been tested.
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12
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Tan KT, Ang STJ, Tsai SY. Sarcopenia: Tilting the Balance of Protein Homeostasis. Proteomics 2019; 20:e1800411. [PMID: 31722440 DOI: 10.1002/pmic.201800411] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2019] [Revised: 11/04/2019] [Indexed: 12/14/2022]
Abstract
Sarcopenia, defined as age-associated decline of muscle mass and function, is a risk factor for mortality and disability, and comorbid with several chronic diseases such as type II diabetes and cardiovascular diseases. Clinical trials showed that nutritional supplements had positive effects on muscle mass, but not on muscle function and strength, demonstrating our limited understanding of the molecular events involved in the ageing muscle. Protein homeostasis, the equilibrium between protein synthesis and degradation, is proposed as the major mechanism underlying the development of sarcopenia. As the key central regulator of protein homeostasis, the mammalian target of rapamycin (mTOR) is proposed to be essential for muscle hypertrophy. Paradoxically, sustained activation of mTOR complex 1 (mTORC1) is associated with a loss of sensitivity to extracellular signaling in the elderly. It is not understood why sustained mTORC1 activity, which should induce muscle hypertrophy, instead results in muscle atrophy. Here, recent findings on the implications of disrupting protein homeostasis on muscle physiology and sarcopenia development in the context of mTOR/protein kinase B (AKT) signaling are reviewed. Understanding the role of these molecular mechanisms during the ageing process will contribute towards the development of targeted therapies that will improve protein metabolism and reduce sarcopenia.
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Affiliation(s)
- Kuan Ting Tan
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, 2 Medical Drive, MD9 Admin Office, Singapore, 117597, Singapore
| | - Seok-Ting Jamie Ang
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, 2 Medical Drive, MD9 Admin Office, Singapore, 117597, Singapore
| | - Shih-Yin Tsai
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, 2 Medical Drive, MD9 Admin Office, Singapore, 117597, Singapore
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13
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MyoRobot 2.0: An advanced biomechatronics platform for automated, environmentally controlled skeletal muscle single fiber biomechanics assessment employing inbuilt real-time optical imaging. Biosens Bioelectron 2019; 138:111284. [DOI: 10.1016/j.bios.2019.04.052] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2019] [Accepted: 04/24/2019] [Indexed: 11/23/2022]
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14
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Hunt LC, Stover J, Haugen B, Shaw TI, Li Y, Pagala VR, Finkelstein D, Barton ER, Fan Y, Labelle M, Peng J, Demontis F. A Key Role for the Ubiquitin Ligase UBR4 in Myofiber Hypertrophy in Drosophila and Mice. Cell Rep 2019; 28:1268-1281.e6. [PMID: 31365869 PMCID: PMC6697171 DOI: 10.1016/j.celrep.2019.06.094] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2018] [Revised: 05/07/2019] [Accepted: 06/26/2019] [Indexed: 12/31/2022] Open
Abstract
Skeletal muscle cell (myofiber) atrophy is a detrimental component of aging and cancer that primarily results from muscle protein degradation via the proteasome and ubiquitin ligases. Transcriptional upregulation of some ubiquitin ligases contributes to myofiber atrophy, but little is known about the role that most other ubiquitin ligases play in this process. To address this question, we have used RNAi screening in Drosophila to identify the function of > 320 evolutionarily conserved ubiquitin ligases in myofiber size regulation in vivo. We find that whereas RNAi for some ubiquitin ligases induces myofiber atrophy, loss of others (including the N-end rule ubiquitin ligase UBR4) promotes hypertrophy. In Drosophila and mouse myofibers, loss of UBR4 induces hypertrophy via decreased ubiquitination and degradation of a core set of target proteins, including the HAT1/RBBP4/RBBP7 histone-binding complex. Together, this study defines the repertoire of ubiquitin ligases that regulate myofiber size and the role of UBR4 in myofiber hypertrophy.
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Affiliation(s)
- Liam C Hunt
- Division of Developmental Biology, St. Jude Children's Research Hospital, 262 Danny Thomas Place, Memphis, TN 38105, USA; Department of Developmental Neurobiology, St. Jude Children's Research Hospital, 262 Danny Thomas Place, Memphis, TN 38105, USA
| | - Jared Stover
- Division of Developmental Biology, St. Jude Children's Research Hospital, 262 Danny Thomas Place, Memphis, TN 38105, USA; Department of Developmental Neurobiology, St. Jude Children's Research Hospital, 262 Danny Thomas Place, Memphis, TN 38105, USA
| | - Benard Haugen
- Division of Developmental Biology, St. Jude Children's Research Hospital, 262 Danny Thomas Place, Memphis, TN 38105, USA; Department of Developmental Neurobiology, St. Jude Children's Research Hospital, 262 Danny Thomas Place, Memphis, TN 38105, USA
| | - Timothy I Shaw
- Department of Structural Biology, Center for Proteomics and Metabolomics, St. Jude Children's Research Hospital, 262 Danny Thomas Place, Memphis, TN 38105, USA
| | - Yuxin Li
- Department of Structural Biology, Center for Proteomics and Metabolomics, St. Jude Children's Research Hospital, 262 Danny Thomas Place, Memphis, TN 38105, USA
| | - Vishwajeeth R Pagala
- Department of Structural Biology, Center for Proteomics and Metabolomics, St. Jude Children's Research Hospital, 262 Danny Thomas Place, Memphis, TN 38105, USA
| | - David Finkelstein
- Department of Computational Biology, St. Jude Children's Research Hospital, 262 Danny Thomas Place, Memphis, TN 38105, USA
| | - Elisabeth R Barton
- College of Health & Human Performance Applied Physiology & Kinesiology, University of Florida, 124 Florida Gym, 1864 Stadium Road, Gainesville, FL 32611, USA
| | - Yiping Fan
- Department of Computational Biology, St. Jude Children's Research Hospital, 262 Danny Thomas Place, Memphis, TN 38105, USA
| | - Myriam Labelle
- Department of Developmental Neurobiology, St. Jude Children's Research Hospital, 262 Danny Thomas Place, Memphis, TN 38105, USA; Solid Tumor Program, Comprehensive Cancer Center, St. Jude Children's Research Hospital, 262 Danny Thomas Place, Memphis, TN 38105, USA
| | - Junmin Peng
- Department of Structural Biology, Center for Proteomics and Metabolomics, St. Jude Children's Research Hospital, 262 Danny Thomas Place, Memphis, TN 38105, USA; Department of Developmental Neurobiology, St. Jude Children's Research Hospital, 262 Danny Thomas Place, Memphis, TN 38105, USA
| | - Fabio Demontis
- Division of Developmental Biology, St. Jude Children's Research Hospital, 262 Danny Thomas Place, Memphis, TN 38105, USA; Department of Developmental Neurobiology, St. Jude Children's Research Hospital, 262 Danny Thomas Place, Memphis, TN 38105, USA.
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15
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Ahtiainen JP, Lensu S, Ruotsalainen I, Schumann M, Ihalainen JK, Fachada V, Mendias CL, Brook MS, Smith K, Atherton PJ, Koch LG, Britton SL, Kainulainen H. Physiological adaptations to resistance training in rats selectively bred for low and high response to aerobic exercise training. Exp Physiol 2018; 103:1513-1523. [PMID: 30184287 DOI: 10.1113/ep087144] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2018] [Accepted: 09/03/2018] [Indexed: 01/28/2023]
Abstract
NEW FINDINGS What is the central question of this study? Can phenotypic traits associated with low response to one mode of training be extrapolated to other exercise-inducible phenotypes? The present study investigated whether rats that are low responders to endurance training are also low responders to resistance training. What is the main finding and its importance? After resistance training, rats that are high responders to aerobic exercise training improved more in maximal strength compared with low-responder rats. However, the greater gain in strength in high-responder rats was not accompanied by muscle hypertrophy, suggesting that the responses observed could be mainly neural in origin. ABSTRACT The purpose of this study was to determine whether rats selectively bred for low and high response to aerobic exercise training co-segregate for differences in muscle adaptations to ladder-climbing resistance training. Five high-responder (HRT) and five low-responder (LRT) rats completed the resistance training, while six HRT and six LRT rats served as sedentary control animals. Before and after the 6 week intervention, body composition was determined by dual energy X-ray absorptiometry. Before tissue harvesting, the right triceps surae muscles were loaded by electrical stimulation. Muscle fibre cross-sectional areas, nuclei per cell, phosphorylation status of selected signalling proteins of mTOR and Smad pathways, and muscle protein, DNA and RNA concentrations were determined for the right gastrocnemius muscle. The daily protein synthesis rate was determined by the deuterium oxide method from the left quadriceps femoris muscle. Tissue weights of fore- and hindlimb muscles were measured. In response to resistance training, maximal carrying capacity was greater in HRT (∼3.3 times body mass) than LRT (∼2.5 times body mass), indicating greater improvements of strength in HRT. However, muscle hypertrophy that could be related to greater strength gains in HRT was not observed. Furthermore, noteworthy changes within the experimental groups or differences between groups were not observed in the present measures. The lack of hypertrophic muscular adaptations despite considerable increases in muscular strength suggest that adaptations to the present ladder-climbing training in HRT and LRT rats were largely induced by neural adaptations.
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Affiliation(s)
- Juha P Ahtiainen
- Neuromuscular Research Center, Faculty of Sport and Health Sciences, University of Jyväskylä, Jyväskylä, Finland
| | - Sanna Lensu
- Neuromuscular Research Center, Faculty of Sport and Health Sciences, University of Jyväskylä, Jyväskylä, Finland
| | | | - Moritz Schumann
- German Sport University, Institute of Cardiovascular Research and Sport Medicine, Department of Molecular and Cellular Sport Medicine, Cologne, Germany
| | - Johanna K Ihalainen
- Neuromuscular Research Center, Faculty of Sport and Health Sciences, University of Jyväskylä, Jyväskylä, Finland
| | - Vasco Fachada
- Neuromuscular Research Center, Faculty of Sport and Health Sciences, University of Jyväskylä, Jyväskylä, Finland
| | | | - Matthew S Brook
- MRC-ARUK Centre of Excellence for Musculoskeletal Ageing Research, School of Medicine, University of Nottingham, Derby, UK
| | - Kenneth Smith
- MRC-ARUK Centre of Excellence for Musculoskeletal Ageing Research, School of Medicine, University of Nottingham, Derby, UK
| | - Philip J Atherton
- MRC-ARUK Centre of Excellence for Musculoskeletal Ageing Research, School of Medicine, University of Nottingham, Derby, UK
| | - Lauren G Koch
- Department of Physiology and Pharmacology, The University of Toledo, College of Medicine and Life Sciences, Toledo, OH, USA
| | - Steven L Britton
- Department of Anesthesiology, University of Michigan, Ann Arbor, MI, USA.,Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI, USA
| | - Heikki Kainulainen
- Neuromuscular Research Center, Faculty of Sport and Health Sciences, University of Jyväskylä, Jyväskylä, Finland
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16
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Lin YS, Lin FY, Hsiao YH. Myostatin Is Associated With Cognitive Decline in an Animal Model of Alzheimer's Disease. Mol Neurobiol 2018; 56:1984-1991. [PMID: 29982981 DOI: 10.1007/s12035-018-1201-y] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2018] [Accepted: 06/26/2018] [Indexed: 12/22/2022]
Abstract
With aging, there are progressive functional declines in multiple organ systems. One of the major physiological problems observed in aged people is skeletal muscle loss. This age-related muscle loss causes muscle weakness and disability, which in turn might reduce the quality of life in older adults and lead to the progression of several diseases, particularly Alzheimer's disease (AD). Some researchers have hypothesized that loss of muscle mass and strength is linked to the risk of developing AD. In addition, unintended weight loss often occurs in AD patients and might reflect dementia severity. However, the causal relationship between muscle atrophy and cognitive deficits in AD is unclear. We found that double transgenic amyloid precursor protein and presenilin 1 (APP/PS1) mice that co-express APP and PS1 at older ages exhibited lower body weight and lean tissue mass than sex- and age-matched wild-type (WT) mice. In addition, muscle atrophy and the extent of memory decline were strongly correlated in APP/PS1 mice. Myostatin levels in the gastrocnemius (GAS) muscle of 12-month-old APP/PS1 mice were elevated. We determined that the cellular and molecular mechanism of muscle atrophy was through the ubiquitin-proteasome pathway. Furthermore, myostatin knockdown in the GAS muscles increased grip strength and muscle mass, leading to memory improvement in myostatin short-hairpin RNA-treated APP/PS1 mice. We conclude that high-level myostatin expression might mediate or trigger muscle atrophy and cognitive deficits.
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Affiliation(s)
- Yung-Shuen Lin
- Department of Pharmacology, College of Medicine, National Cheng Kung University, Tainan, 70101, Taiwan
| | - Fang-Yu Lin
- Department of Pharmacology, College of Medicine, National Cheng Kung University, Tainan, 70101, Taiwan
| | - Ya-Hsin Hsiao
- Department of Pharmacology, College of Medicine, National Cheng Kung University, Tainan, 70101, Taiwan. .,Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung University, Tainan, Taiwan. .,Institute of Behavioral Medicine, College of Medicine, National Cheng Kung University, Tainan, Taiwan.
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17
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Preclinical characterization of the JAK/STAT inhibitor SGI-1252 on skeletal muscle function, morphology, and satellite cell content. PLoS One 2018; 13:e0198611. [PMID: 29897957 PMCID: PMC5999283 DOI: 10.1371/journal.pone.0198611] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2018] [Accepted: 05/22/2018] [Indexed: 01/20/2023] Open
Abstract
Background Recent studies have highlighted the JAK/STAT signaling pathway in the regulation of muscle satellite cell behavior. Herein we report preclinical studies designed to characterize the effects of a novel JAK/STAT inhibitor on plantar flexor skeletal muscle function, morphology, and satellite cell content. Methods The compound, SGI-1252, was administered orally (400mg/kg) in a 10% dextrose solution to wild type mice (n = 6) 3 times per week for 8 weeks. A control group (n = 6) received only the dextrose solution. Results SGI-1252 was well tolerated, as animals displayed similar weight gain over the 8-week treatment period. Following treatment, fatigue in the gastrocnemius-soleus-plantaris complex was greater in the SGI-1252 mice during a 300 second tetanic contraction bout (p = 0.035), though both the rate of fatigue and maximal force production were similar. SGI-1252 treated mice had increased type II myofiber cross-sectional area (1434.8 ± 225.4 vs 1754.7 ± 138.5 μm2), along with an increase in wet muscle mass (125.45 ± 5.46 vs 139.6 ± 12.34 mg, p = 0.032) of the gastrocnemius relative to vehicle treated mice. SGI-1252 treatment reduced gastrocnemius STAT3 phosphorylation 53% (94.79 ± 45.9 vs 44.5 ± 6.1 MFI) and significantly increased the concentration of Pax7+ satellite cells (2589.2 ± 105.5 vs 2859.4 ± 177.5 SC/mm3) in the gastrocnemius. SGI-1252 treatment suppressed MyoD (p = 0.013) and Myogenin (p<0.0001) expression in human primary myoblasts, resulting in reduced myogenic differentiation (p = 0.039). Conclusions Orally delivered SGI-1252 was well tolerated, attenuates skeletal muscle STAT3 activity, and increases satellite cell content in mouse gastrocnemius muscle, likely by inhibiting myogenic progression.
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Novakova SS, Mahalingam VD, Florida SE, Mendias CL, Allen A, Arruda EM, Bedi A, Larkin LM. Tissue-engineered tendon constructs for rotator cuff repair in sheep. J Orthop Res 2018; 36:289-299. [PMID: 28657154 DOI: 10.1002/jor.23642] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/24/2017] [Accepted: 06/25/2017] [Indexed: 02/04/2023]
Abstract
Current rotator cuff repair commonly involves the use of single or double row suture techniques, and despite successful outcomes, failure rates continue to range from 20 to 95%. Failure to regenerate native biomechanical properties at the enthesis is thought to contribute to failure rates. Thus, the need for technologies that improve structural healing of the enthesis after rotator cuff repair is imperative. To address this issue, our lab has previously demonstrated enthesis regeneration using a tissue-engineered graft approach in a sheep anterior cruciate ligament (ACL) repair model. We hypothesized that our tissue-engineered graft designed for ACL repair also will be effective in rotator cuff repair. The goal of this study was to test the efficacy of our Engineered Tissue Graft for Rotator Cuff (ETG-RC) in a rotator cuff tear model in sheep and compare this novel graft technology to the commonly used double row suture repair technique. Following a 6-month recovery, the grafted and contralateral shoulders were removed, imaged using X-ray, and tested biomechanically. Additionally, the infraspinatus muscle, myotendinous junction, enthesis, and humeral head were preserved for histological analysis of muscle, tendon, and enthesis structure. Our results showed that our ETC-RCs reached 31% of the native tendon tangent modulus, which was a modest, non-significant, 11% increase over that of the suture-only repairs. However, the histological analysis showed the regeneration of a native-like enthesis in the ETG-RC-repaired animals. This advanced structural healing may improve over longer times and may diminish recurrence rates of rotator cuff tears and lead to better clinical outcomes. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:289-299, 2018.
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Affiliation(s)
- Stoyna S Novakova
- Departments of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, Michigan 48109-2200Michigan 48109-2200
| | - Vasudevan D Mahalingam
- Departments of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, Michigan 48109-2200Michigan 48109-2200
| | - Shelby E Florida
- Departments of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, Michigan 48109-2200Michigan 48109-2200
| | - Christopher L Mendias
- Departments of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, Michigan 48109-2200Michigan 48109-2200.,Departments of Orthopaedic Surgery, University of Michigan, Ann Arbor, Michigan 48109-2200
| | | | - Ellen M Arruda
- Departments of Mechanical Engineering, University of Michigan, Ann Arbor, Michigan 48109-2200.,Departments of Biomedical Engineering, University of Michigan, Ann Arbor, Michigan 48109-2200.,Departments of Macromolecular Science and Engineering, University of Michigan, Ann Arbor, Michigan 48109-2200
| | - Asheesh Bedi
- Departments of Orthopaedic Surgery, University of Michigan, Ann Arbor, Michigan 48109-2200
| | - Lisa M Larkin
- Departments of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, Michigan 48109-2200Michigan 48109-2200.,Departments of Biomedical Engineering, University of Michigan, Ann Arbor, Michigan 48109-2200
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19
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The MyoRobot: A novel automated biomechatronics system to assess voltage/Ca 2+ biosensors and active/passive biomechanics in muscle and biomaterials. Biosens Bioelectron 2017; 102:589-599. [PMID: 29245144 DOI: 10.1016/j.bios.2017.12.003] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2017] [Revised: 11/11/2017] [Accepted: 12/05/2017] [Indexed: 11/21/2022]
Abstract
We engineered an automated biomechatronics system, MyoRobot, for robust objective and versatile assessment of muscle or polymer materials (bio-)mechanics. It covers multiple levels of muscle biosensor assessment, e.g. membrane voltage or contractile apparatus Ca2+ ion responses (force resolution 1µN, 0-10mN for the given sensor; [Ca2+] range ~ 100nM-25µM). It replaces previously tedious manual protocols to obtain exhaustive information on active/passive biomechanical properties across various morphological tissue levels. Deciphering mechanisms of muscle weakness requires sophisticated force protocols, dissecting contributions from altered Ca2+ homeostasis, electro-chemical, chemico-mechanical biosensors or visco-elastic components. From whole organ to single fibre levels, experimental demands and hardware requirements increase, limiting biomechanics research potential, as reflected by only few commercial biomechatronics systems that can address resolution, experimental versatility and mostly, automation of force recordings. Our MyoRobot combines optical force transducer technology with high precision 3D actuation (e.g. voice coil, 1µm encoder resolution; stepper motors, 4µm feed motion), and customized control software, enabling modular experimentation packages and automated data pre-analysis. In small bundles and single muscle fibres, we demonstrate automated recordings of (i) caffeine-induced-, (ii) electrical field stimulation (EFS)-induced force, (iii) pCa-force, (iv) slack-tests and (v) passive length-tension curves. The system easily reproduces results from manual systems (two times larger stiffness in slow over fast muscle) and provides novel insights into unloaded shortening velocities (declining with increasing slack lengths). The MyoRobot enables automated complex biomechanics assessment in muscle research. Applications also extend to material sciences, exemplarily shown here for spider silk and collagen biopolymers.
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20
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Wurtzel CNW, Gumucio JP, Grekin JA, Khouri RK, Davis CS, Russell AJ, Bedi A, Mendias CL. Pharmacological inhibition of myostatin protects against skeletal muscle atrophy and weakness after anterior cruciate ligament tear. J Orthop Res 2017; 35:2499-2505. [PMID: 28176368 PMCID: PMC5548641 DOI: 10.1002/jor.23537] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/26/2016] [Accepted: 02/02/2017] [Indexed: 02/04/2023]
Abstract
Anterior cruciate ligament (ACL) tears are among the most frequent knee injuries in sports medicine, with tear rates in the US up to 250,000 per year. Many patients who suffer from ACL tears have persistent atrophy and weakness even after considerable rehabilitation. Myostatin is a cytokine that directly induces muscle atrophy, and previous studies rodent models and patients have demonstrated an upregulation of myostatin after ACL tear. Using a preclinical rat model, our objective was to determine if the use of a bioneutralizing antibody against myostatin could prevent muscle atrophy and weakness after ACL tear. Rats underwent a surgically induced ACL tear and were treated with either a bioneutralizing antibody against myostatin (10B3, GlaxoSmithKline) or a sham antibody (E1-82.15, GlaxoSmithKline). Muscles were harvested at either 7 or 21 days after induction of a tear to measure changes in contractile function, fiber size, and genes involved in muscle atrophy and hypertrophy. These time points were selected to evaluate early and later changes in muscle structure and function. Compared to the sham antibody group, 7 days after ACL tear, myostatin inhibition reduced the expression of proteolytic genes and induced the expression of hypertrophy genes. These early changes in gene expression lead to a 22% increase in muscle fiber cross-sectional area and a 10% improvement in maximum isometric force production that were observed 21 days after ACL tear. Overall, myostatin inhibition lead to several favorable, although modest, changes in molecular biomarkers of muscle regeneration and reduced muscle atrophy and weakness following ACL tear. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:2499-2505, 2017.
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Affiliation(s)
- Caroline N W Wurtzel
- Department of Orthopaedic Surgery, University of Michigan Medical School, 109 Zina Pitcher Place, Ann Arbor, MI, 48109
| | - Jonathan P Gumucio
- Department of Orthopaedic Surgery, University of Michigan Medical School, 109 Zina Pitcher Place, Ann Arbor, MI, 48109,Department of Molecular & Integrative Physiology, University of Michigan Medical School, 109 Zina Pitcher Place, Ann Arbor, MI, 48109
| | - Jeremy A Grekin
- Department of Orthopaedic Surgery, University of Michigan Medical School, 109 Zina Pitcher Place, Ann Arbor, MI, 48109
| | - Roger K Khouri
- Department of Orthopaedic Surgery, University of Michigan Medical School, 109 Zina Pitcher Place, Ann Arbor, MI, 48109
| | - Carol S Davis
- Department of Molecular & Integrative Physiology, University of Michigan Medical School, 109 Zina Pitcher Place, Ann Arbor, MI, 48109
| | - Alan J Russell
- Muscle Metabolism DPU, GlaxoSmithKline Pharmaceuticals, 2301 Renaissance Blvd, King of Prussia, PA, 19406
| | - Asheesh Bedi
- Department of Orthopaedic Surgery, University of Michigan Medical School, 109 Zina Pitcher Place, Ann Arbor, MI, 48109
| | - Christopher L Mendias
- Department of Orthopaedic Surgery, University of Michigan Medical School, 109 Zina Pitcher Place, Ann Arbor, MI, 48109,Department of Molecular & Integrative Physiology, University of Michigan Medical School, 109 Zina Pitcher Place, Ann Arbor, MI, 48109,To whom correspondence should be addressed: Christopher L Mendias, PhD, ATC, Department of Orthopaedic Surgery, University of Michigan Medical School, 109 Zina Pitcher Place, BSRB 2017, Ann Arbor, MI 48109-2200, 734-764-3250,
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Egner IM, Bruusgaard JC, Gundersen K. Satellite cell depletion prevents fiber hypertrophy in skeletal muscle. Development 2017; 143:2898-906. [PMID: 27531949 DOI: 10.1242/dev.134411] [Citation(s) in RCA: 142] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2015] [Accepted: 06/28/2016] [Indexed: 12/18/2022]
Abstract
The largest mammalian cells are the muscle fibers, and they have multiple nuclei to support their large cytoplasmic volumes. During hypertrophic growth, new myonuclei are recruited from satellite stem cells into the fiber syncytia, but it was recently suggested that such recruitment is not obligatory: overload hypertrophy after synergist ablation of the plantaris muscle appeared normal in transgenic mice in which most of the satellite cells were abolished. When we essentially repeated these experiments analyzing the muscles by immunohistochemistry and in vivo and ex vivo imaging, we found that overload hypertrophy was prevented in the satellite cell-deficient mice, in both the plantaris and the extensor digitorum longus muscles. We attribute the previous findings to a reliance on muscle mass as a proxy for fiber hypertrophy, and to the inclusion of a significant number of regenerating fibers in the analysis. We discuss that there is currently no model in which functional, sustainable hypertrophy has been unequivocally demonstrated in the absence of satellite cells; an exception is re-growth, which can occur using previously recruited myonuclei without addition of new myonuclei.
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Affiliation(s)
- Ingrid M Egner
- Department of Biosciences, University of Oslo, Blindern, Oslo N-0316, Norway
| | - Jo C Bruusgaard
- Department of Biosciences, University of Oslo, Blindern, Oslo N-0316, Norway Department of Health Sciences, Kristiania University College, P.O. Box 1190, Sentrum, Oslo N-0107, Norway
| | - Kristian Gundersen
- Department of Biosciences, University of Oslo, Blindern, Oslo N-0316, Norway
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Ueberschlag-Pitiot V, Stantzou A, Messéant J, Lemaitre M, Owens DJ, Noirez P, Roy P, Agbulut O, Metzger D, Ferry A. Gonad-related factors promote muscle performance gain during postnatal development in male and female mice. Am J Physiol Endocrinol Metab 2017; 313:E12-E25. [PMID: 28351832 DOI: 10.1152/ajpendo.00446.2016] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/13/2016] [Revised: 02/22/2017] [Accepted: 03/22/2017] [Indexed: 11/22/2022]
Abstract
To better define the role of male and female gonad-related factors (MGRF, presumably testosterone, and FGRF, presumably estradiol, respectively) on mouse hindlimb skeletal muscle contractile performance/function gain during postnatal development, we analyzed the effect of castration initiated before puberty in male and female mice. We found that muscle absolute and specific (normalized to muscle weight) maximal forces were decreased in 6-mo-old male and female castrated mice compared with age- and sex-matched intact mice, without alteration in neuromuscular transmission. Moreover, castration decreased absolute and specific maximal powers, another important aspect of muscle performance, in 6-mo-old males, but not in females. Absolute maximal force was similarly reduced by castration in 3-mo-old muscle fiber androgen receptor (AR)-deficient and wild-type male mice, indicating that the effect of MGRF was muscle fiber AR independent. Castration reduced the muscle weight gain in 3-mo mice of both sexes and in 6-mo females but not in males. We also found that bone morphogenetic protein signaling through Smad1/5/9 was not altered by castration in atrophic muscle of 3-mo-old mice of both sexes. Moreover, castration decreased the sexual dimorphism regarding muscle performance. Together, these results demonstrated that in the long term, MGRF and FGRF promote muscle performance gain in mice during postnatal development, independently of muscle growth in males, largely via improving muscle contractile quality (force and power normalized), and that MGFR and FGRF also contribute to sexual dimorphism. However, the mechanisms underlying MGFR and FGRF actions remain to be determined.
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Affiliation(s)
- Vanessa Ueberschlag-Pitiot
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, Université de Strasbourg, CNRS UMR7104/INSERM U964, Illkirch, France
| | - Amalia Stantzou
- Sorbonne Universités, Université Pierre et Marie Curie-Paris6, Myology Research Center, UM76 and INSERM U974 and CNRS FRE 3617 and Institut de Myologie, Paris, France
| | - Julien Messéant
- Sorbonne Universités, Université Pierre et Marie Curie-Paris6, Myology Research Center, UM76 and INSERM U974 and CNRS FRE 3617 and Institut de Myologie, Paris, France
| | - Megane Lemaitre
- Sorbonne Universités, Université Pierre et Marie Curie-Paris6, Myology Research Center, UM76 and INSERM U974 and CNRS FRE 3617 and Institut de Myologie, Paris, France
| | - Daniel J Owens
- Sorbonne Universités, Université Pierre et Marie Curie-Paris6, Myology Research Center, UM76 and INSERM U974 and CNRS FRE 3617 and Institut de Myologie, Paris, France
| | - Philippe Noirez
- Institut de Recherche Biomédicale et D'épidemiologie du Sport, EA 7329, Institut National du Sport de l'Expertise et de la Performance, Laboratory of Excellence GR-Ex, Paris, France
- Université Sorbonne Paris Cité, Université Paris Descartes, Paris, France; and
| | - Pauline Roy
- Sorbonne Universités, Université Pierre et Marie Curie-Paris6, Myology Research Center, UM76 and INSERM U974 and CNRS FRE 3617 and Institut de Myologie, Paris, France
| | - Onnik Agbulut
- Sorbonne Universités, Université Pierre et Marie Curie-Paris6, Institut de Biologie Paris-Seine, UMR CNRS 8256, Biological Adaptation and Ageing, Paris, France
| | - Daniel Metzger
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, Université de Strasbourg, CNRS UMR7104/INSERM U964, Illkirch, France
| | - Arnaud Ferry
- Sorbonne Universités, Université Pierre et Marie Curie-Paris6, Myology Research Center, UM76 and INSERM U974 and CNRS FRE 3617 and Institut de Myologie, Paris, France;
- Université Sorbonne Paris Cité, Université Paris Descartes, Paris, France; and
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23
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Dietary leucine supplementation alters energy metabolism and induces slow-to-fast transitions in longissimus dorsi muscle of weanling piglets. Br J Nutr 2017. [DOI: 10.1017/s0007114517001209] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
AbstractLeucine plays an important role in promoting muscle protein synthesis and muscle remodelling. However, what percentage of leucine is appropriate in creep feed and what proteome profile alterations are caused by dietary leucine in the skeletal muscle of piglets remain elusive. In this case, we applied isobaric tags for relative and absolute quantitation to analyse the proteome profile of the longissimus dorsi muscles of weanling piglets fed a normal leucine diet (NL; 1·66 % leucine) and a high-leucine diet (HL; 2·1 % leucine). We identified 157 differentially expressed proteins between these two groups. Bioinformatics analysis of these proteins exhibited the suppression of oxidative phosphorylation and fatty acid β-oxidation, as well as the activation of glycolysis, in the HL group. For further confirmation, we identified that SDHB, ATP5F1, ACADM and HADHB were significantly down-regulated (P<0·01, except ATP5F1, P<0·05), whereas the glycolytic enzyme pyruvate kinase was significantly up-regulated (P<0·05) in the HL group. We also show that enhanced muscle protein synthesis and the transition from slow-to-fast fibres are altered by leucine. Together, these results indicate that leucine may alter energy metabolism and promote slow-to-fast transitions in the skeletal muscle of weanling piglets.
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Stantzou A, Ueberschlag-Pitiot V, Thomasson R, Furling D, Bonnieu A, Amthor H, Ferry A. Effect of constitutive inactivation of the myostatin gene on the gain in muscle strength during postnatal growth in two murine models. Muscle Nerve 2016; 55:254-261. [PMID: 27312354 DOI: 10.1002/mus.25220] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2015] [Revised: 04/20/2016] [Accepted: 06/13/2016] [Indexed: 11/07/2022]
Abstract
INTRODUCTION The effect of constitutive inactivation of the gene encoding myostatin on the gain in muscle performance during postnatal growth has not been well characterized. METHODS We analyzed 2 murine myostatin knockout (KO) models, (i) the Lee model (KOLee ) and (ii) the Grobet model (KOGrobet ), and measured the contraction of tibialis anterior muscle in situ. RESULTS Absolute maximal isometric force was increased in 6-month-old KOLee and KOGrobet mice, as compared to wild-type mice. Similarly, absolute maximal power was increased in 6-month-old KOLee mice. In contrast, specific maximal force (relative maximal force per unit of muscle mass was decreased in all 6-month-old male and female KO mice, except in 6-month-old female KOGrobet mice, whereas specific maximal power was reduced only in male KOLee mice. CONCLUSIONS Genetic inactivation of myostatin increases maximal force and power, but in return it reduces muscle quality, particularly in male mice. Muscle Nerve 55: 254-261, 2017.
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Affiliation(s)
- Amalia Stantzou
- Université de Versailles Saint-Quentin, Unité de formation et de recherche des sciences de la santé des sciences, Montigny-le-Bretonneux, France
| | - Vanessa Ueberschlag-Pitiot
- Université de Strasbourg, Institut de Génétique et de Biologie Moléculaire et Cellulaire, Illkirch, France
| | - Remi Thomasson
- Université Paris Descartes, Institut de Recherche bio-Médicale et d'Epidémiologie du Sport, Sorbonne Paris Cité, Paris, France
| | - Denis Furling
- Sorbonne Universités CNRS, Centre de Recherche en Myologie, Paris, France
| | - Anne Bonnieu
- INRA, Université Montpellier, Dynamique Musculaire et Métabolisme, Montpellier, France
| | - Helge Amthor
- Université de Versailles Saint-Quentin, Unité de formation et de recherche des sciences de la santé des sciences, Montigny-le-Bretonneux, France
| | - Arnaud Ferry
- Sorbonne Universités CNRS, Centre de Recherche en Myologie, Paris, France
- Université Paris Descartes, Sorbonne Paris Cité, Paris, France
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Gundersen K. Muscle memory and a new cellular model for muscle atrophy and hypertrophy. ACTA ACUST UNITED AC 2016; 219:235-42. [PMID: 26792335 DOI: 10.1242/jeb.124495] [Citation(s) in RCA: 92] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Memory is a process in which information is encoded, stored, and retrieved. For vertebrates, the modern view has been that it occurs only in the brain. This review describes a cellular memory in skeletal muscle in which hypertrophy is 'remembered' such that a fibre that has previously been large, but subsequently lost its mass, can regain mass faster than naive fibres. A new cell biological model based on the literature, with the most reliable methods for identifying myonuclei, can explain this phenomenon. According to this model, previously untrained fibres recruit myonuclei from activated satellite cells before hypertrophic growth. Even if subsequently subjected to grave atrophy, the higher number of myonuclei is retained, and the myonuclei seem to be protected against the elevated apoptotic activity observed in atrophying muscle tissue. Fibres that have acquired a higher number of myonuclei grow faster when subjected to overload exercise, thus the nuclei represent a functionally important 'memory' of previous strength. This memory might be very long lasting in humans, as myonuclei are stable for at least 15 years and might even be permanent. However, myonuclei are harder to recruit in the elderly, and if the long-lasting muscle memory also exists in humans, one should consider early strength training as a public health advice. In addition, myonuclei are recruited during steroid use and encode a muscle memory, at least in rodents. Thus, extending the exclusion time for doping offenders should be considered.
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Affiliation(s)
- Kristian Gundersen
- Department of Biosciences, University of Oslo, Blindernveien 31, Oslo N0316, Norway
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Goetsch KP, Niesler CU. The extracellular matrix regulates the effect of decorin and transforming growth factor beta-2 (TGF-β2) on myoblast migration. Biochem Biophys Res Commun 2016; 479:351-357. [PMID: 27644884 DOI: 10.1016/j.bbrc.2016.09.079] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2016] [Accepted: 09/15/2016] [Indexed: 12/31/2022]
Abstract
Muscular injuries that destroy the basal lamina result in poor functional recovery of skeletal muscle. This is due, in part, to the deposition of structural fibrotic proteins such as fibronectin and collagen by fibroblasts and other cells. Transforming growth factor-β (TGF-β) promotes fibrosis, whereas the proteoglycan decorin is known to act as an anti-fibrotic agent, in part via the binding and neutralization of TGF-β. We have previously established that decorin can alter the migratory response of skeletal muscle myoblasts to the extracellular matrix (ECM) factor collagen, but not fibronectin. We have also shown that TGF-β reduces myoblast migration. In the current study we demonstrate that decorin can dramatically alter the inhibitory role of TGF-β on human myoblast migration and go on to shown that the extracellular matrix can significantly modify this effect. Decorin and TGF-β2 in combination were observed to significantly increase the rate of human myoblast migration, despite the inhibitory effect of TGF-β2 on its own. Furthermore, in the presence of fibronectin, TGF-β2 and decorin no longer acted synergistically to promote migration; while in the presence of collagen I, TGF-β2 failed to inhibit migration. These studies show, for the first time, that decorin can alter the bioactivity of TGF-β2 on human myoblast migration and emphasize the crucial regulatory role of the extracellular matrix in determining the response of skeletal muscle myoblasts to migratory cues.
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Affiliation(s)
- K P Goetsch
- Discipline of Biochemistry, School of Life Sciences, University of KwaZulu-Natal, Pietermaritzburg, South Africa
| | - C U Niesler
- Discipline of Biochemistry, School of Life Sciences, University of KwaZulu-Natal, Pietermaritzburg, South Africa.
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Laurent MR, Dubois V, Claessens F, Verschueren SMP, Vanderschueren D, Gielen E, Jardí F. Muscle-bone interactions: From experimental models to the clinic? A critical update. Mol Cell Endocrinol 2016; 432:14-36. [PMID: 26506009 DOI: 10.1016/j.mce.2015.10.017] [Citation(s) in RCA: 91] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/31/2015] [Revised: 10/13/2015] [Accepted: 10/20/2015] [Indexed: 02/06/2023]
Abstract
Bone is a biomechanical tissue shaped by forces from muscles and gravitation. Simultaneous bone and muscle decay and dysfunction (osteosarcopenia or sarco-osteoporosis) is seen in ageing, numerous clinical situations including after stroke or paralysis, in neuromuscular dystrophies, glucocorticoid excess, or in association with vitamin D, growth hormone/insulin like growth factor or sex steroid deficiency, as well as in spaceflight. Physical exercise may be beneficial in these situations, but further work is still needed to translate acceptable and effective biomechanical interventions like vibration therapy from animal models to humans. Novel antiresorptive and anabolic therapies are emerging for osteoporosis as well as drugs for sarcopenia, cancer cachexia or muscle wasting disorders, including antibodies against myostatin or activin receptor type IIA and IIB (e.g. bimagrumab). Ideally, increasing muscle mass would increase muscle strength and restore bone loss from disuse. However, the classical view that muscle is unidirectionally dominant over bone via mechanical loading is overly simplistic. Indeed, recent studies indicate a role for neuronal regulation of not only muscle but also bone metabolism, bone signaling pathways like receptor activator of nuclear factor kappa-B ligand (RANKL) implicated in muscle biology, myokines affecting bone and possible bone-to-muscle communication. Moreover, pharmacological strategies inducing isolated myocyte hypertrophy may not translate into increased muscle power because tendons, connective tissue, neurons and energy metabolism need to adapt as well. We aim here to critically review key musculoskeletal molecular pathways involved in mechanoregulation and their effect on the bone-muscle unit as a whole, as well as preclinical and emerging clinical evidence regarding the effects of sarcopenia therapies on osteoporosis and vice versa.
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Affiliation(s)
- Michaël R Laurent
- Gerontology and Geriatrics, Department of Clinical and Experimental Medicine, KU Leuven, 3000 Leuven, Belgium; Laboratory of Molecular Endocrinology, Department of Cellular and Molecular Medicine, KU Leuven, 3000 Leuven, Belgium; Centre for Metabolic Bone Diseases, University Hospitals Leuven, 3000 Leuven, Belgium.
| | - Vanessa Dubois
- Laboratory of Molecular Endocrinology, Department of Cellular and Molecular Medicine, KU Leuven, 3000 Leuven, Belgium
| | - Frank Claessens
- Laboratory of Molecular Endocrinology, Department of Cellular and Molecular Medicine, KU Leuven, 3000 Leuven, Belgium
| | - Sabine M P Verschueren
- Research Group for Musculoskeletal Rehabilitation, Department of Rehabilitation Science, KU Leuven, 3000 Leuven, Belgium
| | - Dirk Vanderschueren
- Clinical and Experimental Endocrinology, Department of Clinical and Experimental Medicine, KU Leuven, 3000 Leuven, Belgium
| | - Evelien Gielen
- Gerontology and Geriatrics, Department of Clinical and Experimental Medicine, KU Leuven, 3000 Leuven, Belgium; Centre for Metabolic Bone Diseases, University Hospitals Leuven, 3000 Leuven, Belgium
| | - Ferran Jardí
- Clinical and Experimental Endocrinology, Department of Clinical and Experimental Medicine, KU Leuven, 3000 Leuven, Belgium
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Béchir N, Pecchi É, Relizani K, Vilmen C, Le Fur Y, Bernard M, Amthor H, Bendahan D, Giannesini B. Mitochondrial impairment induced by postnatal ActRIIB blockade does not alter function and energy status in exercising mouse glycolytic muscle in vivo. Am J Physiol Endocrinol Metab 2016; 310:E539-49. [PMID: 26837807 DOI: 10.1152/ajpendo.00370.2015] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/13/2015] [Accepted: 01/24/2016] [Indexed: 11/22/2022]
Abstract
Because it leads to a rapid and massive muscle hypertrophy, postnatal blockade of the activin type IIB receptor (ActRIIB) is a promising therapeutic strategy for counteracting muscle wasting. However, the functional consequences remain very poorly documented in vivo. Here, we have investigated the impact of 8-wk ActRIIB blockade with soluble receptor (sActRIIB-Fc) on gastrocnemius muscle anatomy, energy metabolism, and force-generating capacity in wild-type mice, using totally noninvasive magnetic resonance imaging (MRI) and dynamic(31)P-MRS. Compared with vehicle (PBS) control, sActRIIB-Fc treatment resulted in a dramatic increase in body weight (+29%) and muscle volume (+58%) calculated from hindlimb MR imaging, but did not alter fiber type distribution determined via myosin heavy chain isoform analysis. In resting muscle, sActRIIB-Fc treatment induced acidosis and PCr depletion, thereby suggesting reduced tissue oxygenation. During an in vivo fatiguing exercise (6-min repeated maximal isometric contraction electrically induced at 1.7 Hz), maximal and total absolute forces were larger in sActRIIB-Fc treated animals (+26 and +12%, respectively), whereas specific force and fatigue resistance were lower (-30 and -37%, respectively). Treatment with sActRIIB-Fc further decreased the maximal rate of oxidative ATP synthesis (-42%) and the oxidative capacity (-34%), but did not alter the bioenergetics status in contracting muscle. Our findings demonstrate in vivo that sActRIIB-Fc treatment increases absolute force-generating capacity and reduces mitochondrial function in glycolytic gastrocnemius muscle, but this reduction does not compromise energy status during sustained activity. Overall, these data support the clinical interest of postnatal ActRIIB blockade.
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Affiliation(s)
- Nelly Béchir
- Aix-Marseille Université, CNRS, Centre de Résonance Magnétique Biologique et Médicale, UMR 7339, 13385, Marseille, France; and
| | - Émilie Pecchi
- Aix-Marseille Université, CNRS, Centre de Résonance Magnétique Biologique et Médicale, UMR 7339, 13385, Marseille, France; and
| | - Karima Relizani
- Université de Versailles Saint-Quentin-en-Yvelines, UFR des sciences de la santé, INSERM U1179, LIA BAHN CSM, SQY Therapeutics, 78180 Montigny-le-Bretonneux, France
| | - Christophe Vilmen
- Aix-Marseille Université, CNRS, Centre de Résonance Magnétique Biologique et Médicale, UMR 7339, 13385, Marseille, France; and
| | - Yann Le Fur
- Aix-Marseille Université, CNRS, Centre de Résonance Magnétique Biologique et Médicale, UMR 7339, 13385, Marseille, France; and
| | - Monique Bernard
- Aix-Marseille Université, CNRS, Centre de Résonance Magnétique Biologique et Médicale, UMR 7339, 13385, Marseille, France; and
| | - Helge Amthor
- Université de Versailles Saint-Quentin-en-Yvelines, UFR des sciences de la santé, INSERM U1179, LIA BAHN CSM, SQY Therapeutics, 78180 Montigny-le-Bretonneux, France
| | - David Bendahan
- Aix-Marseille Université, CNRS, Centre de Résonance Magnétique Biologique et Médicale, UMR 7339, 13385, Marseille, France; and
| | - Benoît Giannesini
- Aix-Marseille Université, CNRS, Centre de Résonance Magnétique Biologique et Médicale, UMR 7339, 13385, Marseille, France; and
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Claflin DR, Roche SM, Gumucio JP, Mendias CL, Brooks SV. Assessment of the Contractile Properties of Permeabilized Skeletal Muscle Fibers. Methods Mol Biol 2016; 1460:321-36. [PMID: 27492182 PMCID: PMC11423931 DOI: 10.1007/978-1-4939-3810-0_22] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2023]
Abstract
Permeabilized individual skeletal muscle fibers offer the opportunity to evaluate contractile behavior in a system that is greatly simplified, yet physiologically relevant. Here we describe the steps required to prepare, permeabilize and preserve small samples of skeletal muscle. We then detail the procedures used to isolate individual fiber segments and attach them to an experimental apparatus for the purpose of controlling activation and measuring force generation. We also describe our technique for estimating the cross-sectional area of fiber segments. The area measurement is necessary for normalizing the absolute force to obtain specific force, a measure of the intrinsic force-generating capability of the contractile system.
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Affiliation(s)
- Dennis R Claflin
- Department of Surgery, Section of Plastic Surgery, University of Michigan Medical School, Ann Arbor, MI, USA
- Department of Biomedical Engineering, University of Michigan College of Engineering, Ann Arbor, MI, USA
| | - Stuart M Roche
- Department of Orthopaedic Surgery, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Jonathan P Gumucio
- Department of Orthopaedic Surgery, University of Michigan Medical School, Ann Arbor, MI, USA
- Department of Molecular & Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Christopher L Mendias
- Department of Orthopaedic Surgery, University of Michigan Medical School, Ann Arbor, MI, USA
- Department of Molecular & Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Susan V Brooks
- Department of Biomedical Engineering, University of Michigan College of Engineering, Ann Arbor, MI, USA.
- Department of Molecular & Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI, USA.
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Ozer K, Rojas-Pena A, Mendias CL, Bryner BS, Toomasian C, Bartlett RH. The Effect of Ex Situ Perfusion in a Swine Limb Vascularized Composite Tissue Allograft on Survival up to 24 Hours. J Hand Surg Am 2016; 41:3-12. [PMID: 26710728 DOI: 10.1016/j.jhsa.2015.11.003] [Citation(s) in RCA: 52] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/07/2015] [Revised: 11/01/2015] [Accepted: 11/01/2015] [Indexed: 02/02/2023]
Abstract
PURPOSE To test the potential for the ex situ limb perfusion system to prolong limb allograft survival up to 24 hours. METHODS We used 20 swine for the study. In group 1 (control), 4 limbs were perfused with heparin solution and preserved at 4°C for 6 hours. In group 2, 4 limbs were perfused with autologous blood at 27°C to 32°C for 24 hours. In both groups, limbs were transplanted orthotopically to recipients and monitored for 12 hours. In addition to perfusion parameters, we recorded perfusate gases and electrolytes (pH, pCO2, pO2, O2 saturation, Na, K, Cl, Ca, HCO3, glucose, and lactate) and obtained functional electrostimulation hourly throughout the experiment. Histology samples were obtained for TUNEL staining and single-muscle fiber contractility testing. RESULTS In both groups, hemodynamic variables of circulation remained stable throughout the experiment. Neuromuscular electrical stimulation remained intact until the end of reperfusion in group 2 vs no response in group 1. In group 2, a gradual increase in lactate levels during pump perfusion returned to normal after transplantation. Compared with the contralateral limb in group 2, single-muscle fiber contractility testing showed no significant difference at the end of the experiment. CONCLUSIONS We demonstrated extended limb survival up to 24 hours using normothermic pulsatile perfusion and autologous blood. CLINICAL RELEVANCE Successful prolongation of limb survival using ex situ perfusion methods provides with more time for revascularization of an extremity.
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Affiliation(s)
- Kagan Ozer
- Department of Orthopaedic Surgery, University of Michigan, Ann Arbor, MI.
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31
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Gumucio JP, Sugg KB, Mendias CL. TGF-β superfamily signaling in muscle and tendon adaptation to resistance exercise. Exerc Sport Sci Rev 2015; 43:93-9. [PMID: 25607281 DOI: 10.1249/jes.0000000000000041] [Citation(s) in RCA: 80] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Numerous studies in muscle and tendon have identified a central role of the transforming growth factor-β (TGF-β) superfamily of cytokines in the regulation of extracellular matrix growth and remodeling, protein degradation, and cell proliferation and differentiation. We provide a novel framework for TGF-β and myostatin signaling in controlling the coordinated adaptation of both skeletal muscle and tendon tissue to resistance training.
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Affiliation(s)
- Jonathan P Gumucio
- Departments of 1Orthopaedic Surgery, 2Molecular and Integrative Physiology, and 3Surgery, Section of Plastic Surgery, University of Michigan Medical School, Ann Arbor, MI
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32
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Sanchez B, Li J, Yim S, Pacheck A, Widrick JJ, Rutkove SB. Evaluation of Electrical Impedance as a Biomarker of Myostatin Inhibition in Wild Type and Muscular Dystrophy Mice. PLoS One 2015; 10:e0140521. [PMID: 26485280 PMCID: PMC4618134 DOI: 10.1371/journal.pone.0140521] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2015] [Accepted: 09/28/2015] [Indexed: 12/14/2022] Open
Abstract
Objectives Non-invasive and effort independent biomarkers are needed to better assess the effects of drug therapy on healthy muscle and that affected by muscular dystrophy (mdx). Here we evaluated the use of multi-frequency electrical impedance for this purpose with comparison to force and histological parameters. Methods Eight wild-type (wt) and 10 mdx mice were treated weekly with RAP-031 activin type IIB receptor at a dose of 10 mg kg−1 twice weekly for 16 weeks; the investigators were blinded to treatment and disease status. At the completion of treatment, impedance measurements, in situ force measurements, and histology analyses were performed. Results As compared to untreated animals, RAP-031 wt and mdx treated mice had greater body mass (18% and 17%, p < 0.001 respectively) and muscle mass (25% p < 0.05 and 22% p < 0.001, respectively). The Cole impedance parameters in treated wt mice, showed a 24% lower central frequency (p < 0.05) and 19% higher resistance ratio (p < 0.05); no significant differences were observed in the mdx mice. These differences were consistent with those seen in maximum isometric force, which was greater in the wt animals (p < 0.05 at > 70 Hz), but not in the mdx animals. In contrast, maximum force normalized by muscle mass was unchanged in the wt animals and lower in the mdx animals by 21% (p < 0.01). Similarly, myofiber size was only non-significantly higher in treated versus untreated animals (8% p = 0.44 and 12% p = 0.31 for wt and mdx animals, respectively). Conclusions Our findings demonstrate electrical impedance of muscle reproduce the functional and histological changes associated with myostatin pathway inhibition and do not reflect differences in muscle size or volume. This technique deserves further study in both animal and human therapeutic trials.
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Affiliation(s)
- Benjamin Sanchez
- Department of Neurology, Division of Neuromuscular Diseases, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215-5491, United States of America
- * E-mail:
| | - Jia Li
- Department of Neurology, Division of Neuromuscular Diseases, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215-5491, United States of America
| | - Sung Yim
- Department of Neurology, Division of Neuromuscular Diseases, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215-5491, United States of America
| | - Adam Pacheck
- Department of Neurology, Division of Neuromuscular Diseases, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215-5491, United States of America
| | - Jeffrey J. Widrick
- Division of Genetics and Genomics, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02215-5491, United States of America
| | - Seward B. Rutkove
- Department of Neurology, Division of Neuromuscular Diseases, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215-5491, United States of America
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Roche SM, Gumucio JP, Brooks SV, Mendias CL, Claflin DR. Measurement of Maximum Isometric Force Generated by Permeabilized Skeletal Muscle Fibers. J Vis Exp 2015:e52695. [PMID: 26131687 PMCID: PMC4545153 DOI: 10.3791/52695] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Analysis of the contractile properties of chemically skinned, or permeabilized, skeletal muscle fibers offers a powerful means by which to assess muscle function at the level of the single muscle cell. Single muscle fiber studies are useful in both basic science and clinical studies. For basic studies, single muscle fiber contractility measurements allow investigation of fundamental mechanisms of force production, and analysis of muscle function in the context of genetic manipulations. Clinically, single muscle fiber studies provide useful insight into the impact of injury and disease on muscle function, and may be used to guide the understanding of muscular pathologies. In this video article we outline the steps required to prepare and isolate an individual skeletal muscle fiber segment, attach it to force-measuring apparatus, activate it to produce maximum isometric force, and estimate its cross-sectional area for the purpose of normalizing the force produced.
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Affiliation(s)
- Stuart M Roche
- Department of Orthopaedic Surgery, University of Michigan Medical School
| | - Jonathan P Gumucio
- Department of Orthopaedic Surgery, University of Michigan Medical School; Department of Molecular & Integrative Physiology, University of Michigan Medical School
| | - Susan V Brooks
- Department of Molecular & Integrative Physiology, University of Michigan Medical School; Department of Biomedical Engineering, University of Michigan Medical School
| | - Christopher L Mendias
- Department of Orthopaedic Surgery, University of Michigan Medical School; Department of Molecular & Integrative Physiology, University of Michigan Medical School
| | - Dennis R Claflin
- Department of Biomedical Engineering, University of Michigan Medical School; Department of Surgery, Section of Plastic Surgery, University of Michigan Medical School;
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Garvey SM, Russ DW, Skelding MB, Dugle JE, Edens NK. Molecular and metabolomic effects of voluntary running wheel activity on skeletal muscle in late middle-aged rats. Physiol Rep 2015; 3:3/2/e12319. [PMID: 25716928 PMCID: PMC4393218 DOI: 10.14814/phy2.12319] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
We examined the molecular and metabolomic effects of voluntary running wheel activity in late middle-aged male Sprague Dawley rats (16–17 months). Rats were assigned either continuous voluntary running wheel access for 8 weeks (RW+) or cage-matched without running wheel access (RW−). The 9 RW+ rats averaged 83 m/day (range: 8–163 m), yet exhibited both 84% reduced individual body weight gain (4.3 g vs. 26.3 g, P = 0.02) and 6.5% reduced individual average daily food intake (20.6 g vs. 22.0 g, P = 0.09) over the 8 weeks. Hindlimb muscles were harvested following an overnight fast. Muscle weights and myofiber cross-sectional area showed no difference between groups. Western blots of gastrocnemius muscle lysates with a panel of antibodies suggest that running wheel activity improved oxidative metabolism (53% increase in PGC1α, P = 0.03), increased autophagy (36% increase in LC3B-II/-I ratio, P = 0.03), and modulated growth signaling (26% increase in myostatin, P = 0.04). RW+ muscle also showed 43% increased glycogen phosphorylase expression (P = 0.04) and 45% increased glycogen content (P = 0.04). Metabolomic profiling of plantaris and soleus muscles indicated that even low-volume voluntary running wheel activity is associated with decreases in many long-chain fatty acids (e.g., palmitoleate, myristoleate, and eicosatrienoate) relative to RW− rats. Relative increases in acylcarnitines and acyl glycerophospholipids were also observed in RW+ plantaris. These data establish that even modest amounts of physical activity during late middle-age promote extensive metabolic remodeling of skeletal muscle.
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Affiliation(s)
| | - David W Russ
- Division of Physical Therapy, Ohio University, Athens, Ohio, USA Ohio Musculoskeletal & Neurological Institute (OMNI), Heritage College of Osteopathic Medicine, Athens, Ohio, USA
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Mendias CL, Lynch EB, Gumucio JP, Flood MD, Rittman DS, Van Pelt DW, Roche SM, Davis CS. Changes in skeletal muscle and tendon structure and function following genetic inactivation of myostatin in rats. J Physiol 2015; 593:2037-52. [PMID: 25640143 DOI: 10.1113/jphysiol.2014.287144] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2014] [Accepted: 01/23/2015] [Indexed: 11/08/2022] Open
Abstract
Myostatin is a negative regulator of skeletal muscle and tendon mass. Myostatin deficiency has been well studied in mice, but limited data are available on how myostatin regulates the structure and function of muscles and tendons of larger animals. We hypothesized that, in comparison to wild-type (MSTN(+/+) ) rats, rats in which zinc finger nucleases were used to genetically inactivate myostatin (MSTN(Δ/Δ) ) would exhibit an increase in muscle mass and total force production, a reduction in specific force, an accumulation of type II fibres and a decrease and stiffening of connective tissue. Overall, the muscle and tendon phenotype of myostatin-deficient rats was markedly different from that of myostatin-deficient mice, which have impaired contractility and pathological changes to fibres and their extracellular matrix. Extensor digitorum longus and soleus muscles of MSTN(Δ/Δ) rats demonstrated 20-33% increases in mass, 35-45% increases in fibre number, 20-57% increases in isometric force and no differences in specific force. The insulin-like growth factor-1 pathway was activated to a greater extent in MSTN(Δ/Δ) muscles, but no substantial differences in atrophy-related genes were observed. Tendons of MSTN(Δ/Δ) rats had a 20% reduction in peak strain, with no differences in mass, peak stress or stiffness. The general morphology and gene expression patterns were similar between tendons of both genotypes. This large rodent model of myostatin deficiency did not have the negative consequences to muscle fibres and extracellular matrix observed in mouse models, and suggests that the greatest impact of myostatin in the regulation of muscle mass may not be to induce atrophy directly, but rather to block hypertrophy signalling.
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Affiliation(s)
- Christopher L Mendias
- Department of Orthopaedic Surgery, University of Michigan, Ann Arbor, MI, USA; Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI, USA
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Simvastatin reduces fibrosis and protects against muscle weakness after massive rotator cuff tear. J Shoulder Elbow Surg 2015; 24:280-7. [PMID: 25213828 PMCID: PMC4291297 DOI: 10.1016/j.jse.2014.06.048] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/27/2014] [Revised: 06/14/2014] [Accepted: 06/27/2014] [Indexed: 02/01/2023]
Abstract
BACKGROUND Chronic rotator cuff tears are a common source of shoulder pain and disability, and patients with chronic cuff tears often have substantial weakness, fibrosis, inflammation, and fat accumulation. Identifying therapies to prevent the development of these pathologic processes will likely have a positive impact on clinical outcomes. Simvastatin is a drug with demonstrated anti-inflammatory and antifibrotic effects in many tissues but had not previously been studied in the context of rotator cuff tears. We hypothesized that after the induction of a massive supraspinatus tear, simvastatin would protect muscles from a loss of force production and fibrosis. METHODS We measured changes in muscle fiber contractility, histology, and biochemical markers of fibrosis and fatty infiltration in rats that received a full-thickness supraspinatus tear and were treated with either carrier alone or simvastatin. RESULTS Compared with vehicle-treated controls, simvastatin did not have an appreciable effect on muscle fiber size, but treatment did increase muscle fiber specific force by 20%. Simvastatin also reduced collagen accumulation by 50% but did not affect triglyceride content of muscles. Several favorable changes in the expression of genes and other markers of inflammation, fibrosis, and regeneration were also observed. CONCLUSIONS Simvastatin partially protected muscles from the weakness that occurs as a result of chronic rotator cuff tear. Fibrosis was also markedly reduced in simvastatin-treated animals. Whereas further studies are necessary, statin medication could potentially help improve outcomes for patients with rotator cuff tears.
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Mendias CL, Roche SM, Harning JA, Davis ME, Lynch EB, Sibilsky Enselman ER, Jacobson JA, Claflin DR, Calve S, Bedi A. Reduced muscle fiber force production and disrupted myofibril architecture in patients with chronic rotator cuff tears. J Shoulder Elbow Surg 2015; 24:111-9. [PMID: 25193488 DOI: 10.1016/j.jse.2014.06.037] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/05/2014] [Revised: 05/28/2014] [Accepted: 06/09/2014] [Indexed: 02/01/2023]
Abstract
BACKGROUND A persistent atrophy of muscle fibers and an accumulation of fat, collectively referred to as fatty degeneration, commonly occur in patients with chronic rotator cuff tears. The etiology of fatty degeneration and function of the residual rotator cuff musculature have not been well characterized in humans. We hypothesized that muscles from patients with chronic rotator cuff tears have reduced muscle fiber force production, disordered myofibrils, and an accumulation of fat vacuoles. METHODS The contractility of muscle fibers from biopsy specimens of supraspinatus muscles of 13 patients with chronic full-thickness posterosuperior rotator cuff tears was measured and compared with data from healthy vastus lateralis muscle fibers. Correlations between muscle fiber contractility, American Shoulder and Elbow Surgeons (ASES) scores, and tear size were analyzed. Histology and electron microscopy were also performed. RESULTS Torn supraspinatus muscles had a 30% reduction in maximum isometric force production and a 29% reduction in normalized force compared with controls. Normalized supraspinatus fiber force positively correlated with ASES score and negatively correlated with tear size. Disordered sarcomeres were noted, along with an accumulation of lipid-laden macrophages in the extracellular matrix surrounding supraspinatus muscle fibers. CONCLUSIONS Patients with chronic supraspinatus tears have significant reductions in muscle fiber force production. Force production also correlates with ASES scores and tear size. The structural and functional muscle dysfunction of the residual muscle fibers is independent of the additional area taken up by fibrotic tissue. This work may help establish future therapies to restore muscle function after the repair of chronically torn rotator cuff muscles.
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Affiliation(s)
- Christopher L Mendias
- Department of Orthopaedic Surgery, University of Michigan Medical School, Ann Arbor, MI, USA; Department of Molecular & Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI, USA.
| | - Stuart M Roche
- Department of Orthopaedic Surgery, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Julie A Harning
- Department of Orthopaedic Surgery, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Max E Davis
- Department of Orthopaedic Surgery, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Evan B Lynch
- Department of Orthopaedic Surgery, University of Michigan Medical School, Ann Arbor, MI, USA; Department of Molecular & Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI, USA
| | | | - Jon A Jacobson
- Department of Radiology, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Dennis R Claflin
- Department of Biomedical Engineering, University of Michigan Medical School, Ann Arbor, MI, USA; Department of Surgery, Section of Plastic Surgery, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Sarah Calve
- School of Biomedical Engineering, Purdue University, West Lafayette, IN, USA
| | - Asheesh Bedi
- Department of Orthopaedic Surgery, University of Michigan Medical School, Ann Arbor, MI, USA
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Fry CS, Lee JD, Mula J, Kirby TJ, Jackson JR, Liu F, Yang L, Mendias CL, Dupont-Versteegden EE, McCarthy JJ, Peterson CA. Inducible depletion of satellite cells in adult, sedentary mice impairs muscle regenerative capacity without affecting sarcopenia. Nat Med 2015; 21:76-80. [PMID: 25501907 PMCID: PMC4289085 DOI: 10.1038/nm.3710] [Citation(s) in RCA: 315] [Impact Index Per Article: 35.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2014] [Accepted: 09/04/2014] [Indexed: 12/15/2022]
Abstract
A key determinant of geriatric frailty is sarcopenia, the age-associated loss of skeletal muscle mass and strength. Although the etiology of sarcopenia is unknown, the correlation during aging between the loss of activity of satellite cells, which are endogenous muscle stem cells, and impaired muscle regenerative capacity has led to the hypothesis that the loss of satellite cell activity is also a cause of sarcopenia. We tested this hypothesis in male sedentary mice by experimentally depleting satellite cells in young adult animals to a degree sufficient to impair regeneration throughout the rest of their lives. A detailed analysis of multiple muscles harvested at various time points during aging in different cohorts of these mice showed that the muscles were of normal size, despite low regenerative capacity, but did have increased fibrosis. These results suggest that lifelong reduction of satellite cells neither accelerated nor exacerbated sarcopenia and that satellite cells did not contribute to the maintenance of muscle size or fiber type composition during aging, but that their loss may contribute to age-related muscle fibrosis.
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Affiliation(s)
- Christopher S. Fry
- Department of Rehabilitation Sciences, College of Health Sciences University of Kentucky, Lexington, Kentucky 40536, USA
- Center for Muscle Biology University of Kentucky, Lexington, Kentucky 40536, USA
| | - Jonah D. Lee
- Department of Rehabilitation Sciences, College of Health Sciences University of Kentucky, Lexington, Kentucky 40536, USA
- Center for Muscle Biology University of Kentucky, Lexington, Kentucky 40536, USA
| | - Jyothi Mula
- Department of Rehabilitation Sciences, College of Health Sciences University of Kentucky, Lexington, Kentucky 40536, USA
- Center for Muscle Biology University of Kentucky, Lexington, Kentucky 40536, USA
| | - Tyler J. Kirby
- Center for Muscle Biology University of Kentucky, Lexington, Kentucky 40536, USA
- Department of Physiology, College of Medicine University of Kentucky, Lexington, Kentucky 40536, USA
| | - Janna R. Jackson
- Department of Rehabilitation Sciences, College of Health Sciences University of Kentucky, Lexington, Kentucky 40536, USA
- Center for Muscle Biology University of Kentucky, Lexington, Kentucky 40536, USA
| | - Fujun Liu
- Center for Muscle Biology University of Kentucky, Lexington, Kentucky 40536, USA
- Department of Biostatistics, College of Public Health University of Kentucky, Lexington, Kentucky 40536, USA
| | - Lin Yang
- Center for Muscle Biology University of Kentucky, Lexington, Kentucky 40536, USA
- Department of Biostatistics, College of Public Health University of Kentucky, Lexington, Kentucky 40536, USA
| | | | - Esther E. Dupont-Versteegden
- Department of Rehabilitation Sciences, College of Health Sciences University of Kentucky, Lexington, Kentucky 40536, USA
- Center for Muscle Biology University of Kentucky, Lexington, Kentucky 40536, USA
| | - John J. McCarthy
- Center for Muscle Biology University of Kentucky, Lexington, Kentucky 40536, USA
- Department of Physiology, College of Medicine University of Kentucky, Lexington, Kentucky 40536, USA
| | - Charlotte A. Peterson
- Department of Rehabilitation Sciences, College of Health Sciences University of Kentucky, Lexington, Kentucky 40536, USA
- Center for Muscle Biology University of Kentucky, Lexington, Kentucky 40536, USA
- Department of Physiology, College of Medicine University of Kentucky, Lexington, Kentucky 40536, USA
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Oak NR, Gumucio JP, Flood MD, Saripalli AL, Davis ME, Harning JA, Lynch EB, Roche SM, Bedi A, Mendias CL. Inhibition of 5-LOX, COX-1, and COX-2 increases tendon healing and reduces muscle fibrosis and lipid accumulation after rotator cuff repair. Am J Sports Med 2014; 42:2860-8. [PMID: 25245131 PMCID: PMC4246014 DOI: 10.1177/0363546514549943] [Citation(s) in RCA: 63] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
BACKGROUND The repair and restoration of function after chronic rotator cuff tears are often complicated by muscle atrophy, fibrosis, and fatty degeneration of the diseased muscle. The inflammatory response has been implicated in the development of fatty degeneration after cuff injuries. Licofelone is a novel anti-inflammatory drug that inhibits 5-lipoxygenase (5-LOX), as well as cyclooxygenase (COX)-1 and COX-2 enzymes, which play important roles in inducing inflammation after injuries. While previous studies have demonstrated that nonsteroidal anti-inflammatory drugs and selective inhibitors of COX-2 (coxibs) may prevent the proper healing of muscles and tendons, studies about bone and cartilage have demonstrated that drugs that inhibit 5-LOX concurrently with COX-1 and COX-2 may enhance tissue regeneration. HYPOTHESIS After the repair of a chronic rotator cuff tear in rats, licofelone would increase the load to failure of repaired tendons and increase the force production of muscle fibers. STUDY DESIGN Controlled laboratory study. METHODS Rats underwent supraspinatus release followed by repair 28 days later. After repair, rats began a treatment regimen of either licofelone or a vehicle for 14 days, at which time animals were euthanized. Supraspinatus muscles and tendons were then subjected to contractile, mechanical, histological, and biochemical analyses. RESULTS Compared with controls, licofelone-treated rats had a grossly apparent decrease in inflammation and increased fibrocartilage formation at the enthesis, along with a 62% increase in the maximum load to failure and a 51% increase in peak stress to failure. Licofelone resulted in a marked reduction in fibrosis and lipid content in supraspinatus muscles as well as reduced expression of several genes involved in fatty infiltration. Despite the decline in fibrosis and fat accumulation, muscle fiber specific force production was reduced by 23%. CONCLUSION The postoperative treatment of cuff repair with licofelone may reduce fatty degeneration and enhance the development of a stable bone-tendon interface, although decreases in muscle fiber specific force production were observed, and force production in fact declined. CLINICAL RELEVANCE This study demonstrates that the inhibition of 5-LOX, COX-1, and COX-2 modulates the healing process of repaired rotator cuff tendons. Although further studies are necessary, the treatment of patients with licofelone after cuff repair may improve the development of a stable enthesis and enhance postoperative outcomes.
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Affiliation(s)
- Nikhil R. Oak
- Department of Orthopaedic Surgery, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Jonathan P. Gumucio
- Department of Orthopaedic Surgery, University of Michigan Medical School, Ann Arbor, Michigan, USA.,Department of Molecular & Integrative Physiology, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Michael D. Flood
- Department of Orthopaedic Surgery, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Anjali L. Saripalli
- Department of Orthopaedic Surgery, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Max E. Davis
- Department of Orthopaedic Surgery, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Julie A. Harning
- Department of Orthopaedic Surgery, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Evan B. Lynch
- Department of Orthopaedic Surgery, University of Michigan Medical School, Ann Arbor, Michigan, USA.,Department of Molecular & Integrative Physiology, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Stuart M. Roche
- Department of Orthopaedic Surgery, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Asheesh Bedi
- Department of Orthopaedic Surgery, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Christopher L. Mendias
- Department of Orthopaedic Surgery, University of Michigan Medical School, Ann Arbor, Michigan, USA.,Department of Molecular & Integrative Physiology, University of Michigan Medical School, Ann Arbor, Michigan, USA.,Address correspondence to Christopher L. Mendias, PhD, ATC, Department of Orthopaedic Surgery, University of Michigan Medical School, 109 Zina Pitcher Place, BSRB 2017, Ann Arbor, Ml 48109-2200, USA ()
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Jeffery N, Mendias C. Endocranial and masticatory muscle volumes in myostatin-deficient mice. ROYAL SOCIETY OPEN SCIENCE 2014; 1:140187. [PMID: 26064569 PMCID: PMC4448778 DOI: 10.1098/rsos.140187] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/21/2014] [Accepted: 08/15/2014] [Indexed: 06/04/2023]
Abstract
Structural and functional trade-offs are integral to the evolution of the mammalian skull and its development. This paper examines the potential for enlargement of the masticatory musculature to limit the size of the endocranial cavity by studying a myostatin-deficient mouse model of hypermuscularity (MSTN-/-). The study tests the null prediction that the larger MSTN-/- mice have larger brains compared with wild-type (WT) mice in order to service the larger muscles. Eleven post-mortem MSTN-/- mice and 12 WT mice were imaged at high resolution using contrast enhanced micro-CT. Masticatory muscle volumes (temporalis, masseter, internal and external pterygoids) and endocranial volumes were measured on the basis of two-dimensional manual tracings and the Cavalieri principle. Volumes were compared using Kruskal-Wallis and Student's t-tests. Results showed that the masticatory muscles of the MSTN-/- mice were significantly larger than in the WT mice. Increases were in the region of 17-36% depending on the muscle. Muscles increased in proportion to each other, maintaining percentages in the region of 5, 10, 21 and 62% of total muscle volume for the external ptyergoid, internal pterygoid, temporalis and masseter, respectively. Kruskal-Wallis and t-tests demonstrated that the endocranial volume was significantly larger in the WT mice, approximately 16% larger on average than that seen in the MSTN-/- mice. This comparative reduction of MSTN-/- endocranial size could not be explained in terms of observer bias, ageing, sexual dimorphism or body size scaling. That the results showed a reduction of brain size associated with an increase of muscle size falsifies the null prediction and lends tentative support to the view that the musculature influences brain growth. It remains to be determined whether the observed effect is primarily physical, nutritional, metabolic or molecular in nature.
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Affiliation(s)
- Nathan Jeffery
- Department of Musculoskeletal Biology, Institute of Ageing and Chronic Disease, University of Liverpool, Sherrington Building, Ashton Street, Liverpool L69 3GE, UK
| | - Christopher Mendias
- Department of Orthopaedic Surgery, University of Michigan, Ann Arbor, MI, USA
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41
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Rodriguez J, Vernus B, Chelh I, Cassar-Malek I, Gabillard JC, Hadj Sassi A, Seiliez I, Picard B, Bonnieu A. Myostatin and the skeletal muscle atrophy and hypertrophy signaling pathways. Cell Mol Life Sci 2014; 71:4361-71. [PMID: 25080109 PMCID: PMC11113773 DOI: 10.1007/s00018-014-1689-x] [Citation(s) in RCA: 267] [Impact Index Per Article: 26.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2014] [Revised: 07/16/2014] [Accepted: 07/17/2014] [Indexed: 12/16/2022]
Abstract
Myostatin, a member of the transforming growth factor-β superfamily, is a potent negative regulator of skeletal muscle growth and is conserved in many species, from rodents to humans. Myostatin inactivation can induce skeletal muscle hypertrophy, while its overexpression or systemic administration causes muscle atrophy. As it represents a potential target for stimulating muscle growth and/or preventing muscle wasting, myostatin regulation and functions in the control of muscle mass have been extensively studied. A wealth of data strongly suggests that alterations in skeletal muscle mass are associated with dysregulation in myostatin expression. Moreover, myostatin plays a central role in integrating/mediating anabolic and catabolic responses. Myostatin negatively regulates the activity of the Akt pathway, which promotes protein synthesis, and increases the activity of the ubiquitin-proteasome system to induce atrophy. Several new studies have brought new information on how myostatin may affect both ribosomal biogenesis and translation efficiency of specific mRNA subclasses. In addition, although myostatin has been identified as a modulator of the major catabolic pathways, including the ubiquitin-proteasome and the autophagy-lysosome systems, the underlying mechanisms are only partially understood. The goal of this review is to highlight outstanding questions about myostatin-mediated regulation of the anabolic and catabolic signaling pathways in skeletal muscle. Particular emphasis has been placed on (1) the cross-regulation between myostatin, the growth-promoting pathways and the proteolytic systems; (2) how myostatin inhibition leads to muscle hypertrophy; and (3) the regulation of translation by myostatin.
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Affiliation(s)
- J. Rodriguez
- INRA, UMR866 Dynamique Musculaire Et Métabolisme, Université Montpellier 1, Université Montpellier 2, 2 Place Viala, 34060 Montpellier, France
| | - B. Vernus
- INRA, UMR866 Dynamique Musculaire Et Métabolisme, Université Montpellier 1, Université Montpellier 2, 2 Place Viala, 34060 Montpellier, France
| | - I. Chelh
- INRA, VetAgro Sup, UMR1213 Herbivores, 63122 Saint-Genès-Champanelle, France
| | - I. Cassar-Malek
- INRA, VetAgro Sup, UMR1213 Herbivores, 63122 Saint-Genès-Champanelle, France
| | - J. C. Gabillard
- INRA, UR1037, Fish Physiology and Genomics, Campus de Beaulieu, 35000 Rennes, France
| | - A. Hadj Sassi
- INRA-USC2009, Université Bordeaux 1, Avenue des Facultés, 33405 Talence, France
| | - I. Seiliez
- INRA, UR1067 Nutrition, Métabolisme, Aquaculture, 64310 Saint-Pée-sur-Nivelle, France
| | - B. Picard
- INRA, VetAgro Sup, UMR1213 Herbivores, 63122 Saint-Genès-Champanelle, France
| | - A. Bonnieu
- INRA, UMR866 Dynamique Musculaire Et Métabolisme, Université Montpellier 1, Université Montpellier 2, 2 Place Viala, 34060 Montpellier, France
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Gumucio J, Flood M, Harning J, Phan A, Roche S, Lynch E, Bedi A, Mendias C. T lymphocytes are not required for the development of fatty degeneration after rotator cuff tear. Bone Joint Res 2014; 3:262-72. [PMID: 25185444 PMCID: PMC4220170 DOI: 10.1302/2046-3758.39.2000294] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Objectives Rotator cuff tears are among the most common and debilitating
upper extremity injuries. Chronic cuff tears result in atrophy and
an infiltration of fat into the muscle, a condition commonly referred
to as ‘fatty degeneration’. While stem cell therapies hold promise
for the treatment of cuff tears, a suitable immunodeficient animal
model that could be used to study human or other xenograft-based
therapies for the treatment of rotator cuff injuries had not previously
been identified. Methods A full-thickness, massive supraspinatus and infraspinatus tear
was induced in adult T-cell deficient rats. We hypothesised that,
compared with controls, 28 days after inducing a tear we would observe
a decrease in muscle force production, an accumulation of type IIB
fibres, and an upregulation in the expression of genes involved
with muscle atrophy, fibrosis and inflammation. Results Chronic cuff tears in nude rats resulted in a 30% to 40% decrease
in muscle mass, a 23% reduction in production of muscle force, and
an induction of genes that regulate atrophy, fibrosis, lipid accumulation,
inflammation and macrophage recruitment. Marked large lipid droplet
accumulation was also present. Conclusions The extent of degenerative changes in nude rats was similar to
what was observed in T-cell competent rats. T cells may not play
an important role in regulating muscle degeneration following chronic
muscle unloading. The general similarities between nude and T-cell
competent rats suggest the nude rat is likely an appropriate preclinical
model for the study of xenografts that have the potential to enhance
the treatment of chronically torn rotator cuff muscles. Cite this article: Bone Joint Res 2014;3:262–72.
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Affiliation(s)
- J Gumucio
- University of Michigan, Department of Orthopaedic Surgery, 109 Zina Pitcher Place, BSRB 2017, Ann Arbor, Michigan, 48109-2200, USA
| | - M Flood
- University of Michigan, Department of Orthopaedic Surgery, 109 Zina Pitcher Place, BSRB 2017, Ann Arbor, Michigan, 48109-2200, USA
| | - J Harning
- University of Michigan, Department of Orthopaedic Surgery, 109 Zina Pitcher Place, BSRB 2017, Ann Arbor, Michigan, 48109-2200, USA
| | - A Phan
- University of Michigan, Department of Orthopaedic Surgery, 109 Zina Pitcher Place, BSRB 2017, Ann Arbor, Michigan, 48109-2200, USA
| | - S Roche
- University of Michigan, Department of Orthopaedic Surgery, 109 Zina Pitcher Place, BSRB 2017, Ann Arbor, Michigan, 48109-2200, USA
| | - E Lynch
- University of Michigan, Department of Orthopaedic Surgery, 109 Zina Pitcher Place, BSRB 2017, Ann Arbor, Michigan, 48109-2200, USA
| | - A Bedi
- University of Michigan, Department of Orthopaedic Surgery, 109 Zina Pitcher Place, BSRB 2017, Ann Arbor, Michigan, 48109-2200, USA
| | - C Mendias
- University of Michigan, Department of Orthopaedic Surgery, 109 Zina Pitcher Place, BSRB 2017, Ann Arbor, Michigan, 48109-2200, USA
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43
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Lundberg TR, Fernandez-Gonzalo R, Tesch PA. Exercise-induced AMPK activation does not interfere with muscle hypertrophy in response to resistance training in men. J Appl Physiol (1985) 2014; 116:611-20. [DOI: 10.1152/japplphysiol.01082.2013] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
As aerobic exercise (AE) may interfere with adaptations to resistance exercise (RE), this study explored acute and chronic responses to consecutive AE (∼45 min cycling) and RE (4 × 7 maximal knee extensions) vs. RE only. Ten men performed acute unilateral AE + RE interspersed by 15 min recovery. The contralateral leg was subjected to RE. This exercise paradigm was then implemented in a 5-wk training program. Protein phosphorylation, gene expression, and glycogen content were assessed in biopsies obtained from the vastus lateralis muscle of both legs immediately before and 3 h after acute RE. Quadriceps muscle size and in vivo torque were measured, and muscle samples were analyzed for citrate synthase activity and glycogen concentration, before and after training. Acute AE reduced glycogen content (32%; P < 0.05) and increased ( P < 0.05) phosphorylation of AMPK (1.5-fold) and rpS6 (1.3-fold). Phosphorylation of p70S6K and 4E-BP1 remained unchanged. Myostatin gene expression was downregulated after acute AE + RE but not RE. Muscle size showed greater ( P < 0.05) increase after AE + RE (6%) than RE (3%) training. Citrate synthase activity (18%) and endurance performance (22%) increased ( P < 0.05) after AE + RE but not RE. While training increased ( P < 0.05) in vivo muscle strength in both legs, normalized and concentric torque increased after RE only. Thus AE activates AMPK, reduces glycogen stores, and impairs the progression of concentric force, yet muscle hypertrophic responses to chronic RE training appear not to be compromised.
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Affiliation(s)
- Tommy R. Lundberg
- Department of Health Sciences, Mid Sweden University, Östersund, Sweden
| | - Rodrigo Fernandez-Gonzalo
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden; and
- Department of Laboratory Medicine, Section for Clinical Physiology, Karolinska Institutet, Karolinska University Hospital, Stockholm, Sweden
| | - Per A. Tesch
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden; and
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44
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Gumucio JP, Korn MA, Saripalli AL, Flood MD, Phan AC, Roche SM, Lynch EB, Claflin DR, Bedi A, Mendias CL. Aging-associated exacerbation in fatty degeneration and infiltration after rotator cuff tear. J Shoulder Elbow Surg 2014; 23:99-108. [PMID: 23790676 PMCID: PMC3785561 DOI: 10.1016/j.jse.2013.04.011] [Citation(s) in RCA: 73] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/06/2013] [Revised: 03/27/2013] [Accepted: 04/17/2013] [Indexed: 02/01/2023]
Abstract
BACKGROUND Rotator cuff tears are one of the most common musculoskeletal complaints and a substantial source of morbidity in elderly patients. Chronic cuff tears are associated with muscle atrophy and an infiltration of fat to the area, a condition known as "fatty degeneration." To improve the treatment of cuff tears in elderly patients, a greater understanding of the changes in the contractile properties of muscle fibers and the molecular regulation of fatty degeneration is essential. METHODS Using a full-thickness, massive supraspinatus and infraspinatus tear model in elderly rats, we measured fiber contractility and determined changes in fiber type distribution that develop 30 days after tear. We also measured the expression of messenger RNA and micro-RNA transcripts involved in muscle atrophy, lipid accumulation, and matrix synthesis. We hypothesized that a decrease in specific force of muscle fibers, an accumulation of type IIb fibers, and an upregulation in atrophic, fibrogenic, and inflammatory gene expression would occur in torn cuff muscles. RESULTS Thirty days after the tear, we observed a reduction in muscle fiber force and an induction of RNA molecules that regulate atrophy, fibrosis, lipid accumulation, inflammation, and macrophage recruitment. A marked accumulation of advanced glycation end products and a significant accretion of macrophages in areas of fat accumulation were observed. CONCLUSIONS The extent of degenerative changes in old rats was greater than that observed in adults. In addition, we identified that the ectopic fat accumulation that occurs in chronic cuff tears does not occur by activation of canonical intramyocellular lipid storage and synthesis pathways.
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Affiliation(s)
- Jonathan P Gumucio
- Department Orthopaedic Surgery, University of Michigan Medical School, Ann Arbor, MI, USA; Department of Molecular & Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Michael A Korn
- Department Orthopaedic Surgery, University of Michigan Medical School, Ann Arbor, MI, USA; Department of Molecular & Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Anjali L Saripalli
- Department Orthopaedic Surgery, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Michael D Flood
- Department Orthopaedic Surgery, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Anthony C Phan
- Department Orthopaedic Surgery, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Stuart M Roche
- Department Orthopaedic Surgery, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Evan B Lynch
- Department Orthopaedic Surgery, University of Michigan Medical School, Ann Arbor, MI, USA; Department of Molecular & Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Dennis R Claflin
- Department of Biomedical Engineering, University of Michigan Medical School, Ann Arbor, MI, USA; Section of Plastic Surgery, Department of Surgery, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Asheesh Bedi
- Department Orthopaedic Surgery, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Christopher L Mendias
- Department Orthopaedic Surgery, University of Michigan Medical School, Ann Arbor, MI, USA; Department of Molecular & Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI, USA.
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Smith RC, Lin BK. Myostatin inhibitors as therapies for muscle wasting associated with cancer and other disorders. Curr Opin Support Palliat Care 2013; 7:352-60. [PMID: 24157714 PMCID: PMC3819341 DOI: 10.1097/spc.0000000000000013] [Citation(s) in RCA: 109] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
PURPOSE OF REVIEW This review summarizes recent progress in the development of myostatin inhibitors for the treatment of muscle wasting disorders. It also focuses on findings in myostatin biology that may have implications for the development of antimyostatin therapies. RECENT FINDINGS There has been progress in evaluating antimyostatin therapies in animal models of muscle wasting disorders. Some programs have progressed into clinical development with initial results showing positive impact on muscle volume.In normal mice myostatin deficiency results in enlarged muscles with increased total force but decreased specific force (total force/total mass). An increase in myofibrillar protein synthesis without concomitant satellite cell proliferation and fusion leads to muscle hypertrophy with unchanged myonuclear number. A specific force reduction is not observed when atrophied muscle, the predominant therapeutic target of myostatin inhibitor therapy, is made myostatindeficient.Myostatin has been shown to be expressed by a number of tumor cell lines in mice and man. SUMMARY Myostatin inhibition remains a promising therapeutic strategy for a range of muscle wasting disorders.
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Affiliation(s)
- Rosamund C Smith
- aBiotechnology Discovery Research bOncology Business Unit, Eli Lilly and Company
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46
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Egner IM, Bruusgaard JC, Eftestøl E, Gundersen K. A cellular memory mechanism aids overload hypertrophy in muscle long after an episodic exposure to anabolic steroids. J Physiol 2013; 591:6221-30. [PMID: 24167222 DOI: 10.1113/jphysiol.2013.264457] [Citation(s) in RCA: 79] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Previous strength training with or without the use of anabolic steroids facilitates subsequent re-acquisition of muscle mass even after long intervening periods of inactivity. Based on in vivo and ex vivo microscopy we here propose a cellular memory mechanism residing in the muscle cells. Female mice were treated with testosterone propionate for 14 days, inducing a 66% increase in the number of myonuclei and a 77% increase in fibre cross-sectional area. Three weeks after removing the drug, fibre size was decreased to the same level as in sham treated animals, but the number of nuclei remained elevated for at least 3 months (>10% of the mouse lifespan). At this time, when the myonuclei-rich muscles were exposed to overload-exercise for 6 days, the fibre cross-sectional area increased by 31% while control muscles did not grow significantly. We suggest that the lasting, elevated number of myonuclei constitutes a cellular memory facilitating subsequent muscle overload hypertrophy. Our findings might have consequences for the exclusion time of doping offenders. Since the ability to generate new myonuclei is impaired in the elderly our data also invites speculation that it might be beneficial to perform strength training when young in order to benefit in senescence.
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Affiliation(s)
- Ingrid M Egner
- K. Gundersen: Department of Biosciences, University of Oslo, PO Box 1066 Blindern, N-0316 Oslo, Norway.
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47
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Mendias CL, Lynch EB, Davis ME, Enselman ERS, Harning JA, DeWolf PD, Makki TA, Bedi A. Changes in circulating biomarkers of muscle atrophy, inflammation, and cartilage turnover in patients undergoing anterior cruciate ligament reconstruction and rehabilitation. Am J Sports Med 2013; 41:1819-26. [PMID: 23739685 PMCID: PMC4086614 DOI: 10.1177/0363546513490651] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
BACKGROUND After anterior cruciate ligament (ACL) reconstruction, there is significant atrophy of the quadriceps muscles that can limit full recovery and place athletes at risk for recurrent injuries with return to play. The cause of this muscle atrophy is not fully understood. HYPOTHESIS Circulating levels of proatrophy, proinflammatory, and cartilage turnover cytokines and biomarkers would increase after ACL reconstruction. STUDY DESIGN Descriptive laboratory study. METHODS Patients (N = 18; mean age, 28 ± 2.4 years) underwent surgical reconstruction of the ACL after a noncontact athletic injury. Circulating levels of biomarkers were measured along with Short Form-12, International Knee Documentation Committee, and objective knee strength measures preoperatively and at 6 postoperative visits. Differences were tested using repeated-measures 1-way analysis of variance. RESULTS Myostatin, TGF-β, and C-reactive protein levels were significantly increased in the early postoperative period and returned to baseline. Cartilage oligomeric matrix protein levels decreased immediately after surgery and then returned to baseline. CCL2, CCL3, CCL4, CCL5, EGF, FGF-2, IGF-1, IL-10, IL-1α, IL-1β, IL-1ra, IL-6, myoglobin, and TNF-α were not different over the course of the study. CONCLUSION An increase in potent atrophy-inducing cytokines and corresponding changes in knee strength and functional scores were observed after ACL reconstruction. CLINICAL RELEVANCE Although further studies are necessary, the therapeutic inhibition of myostatin may help prevent the muscle atrophy that occurs after ACL reconstruction and provide an accelerated return of patients to sport.
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Affiliation(s)
- Christopher L Mendias
- Department of Orthopaedic Surgery, University of Michigan Medical School, Ann Arbor,Department of Molecular & Integrative Physiology, University of Michigan Medical School, Ann Arbor,Address Correspondence To: Christopher L Mendias, PhD, ATC, Department of Orthopaedic Surgery, University of Michigan Medical School, 109 Zina Pitcher Place, BSRB 2017, Ann Arbor, MI 48109-2200, 734-764-3250 office, 734-647-0003 fax,
| | - Evan B Lynch
- Department of Orthopaedic Surgery, University of Michigan Medical School, Ann Arbor,Department of Molecular & Integrative Physiology, University of Michigan Medical School, Ann Arbor
| | - Max E Davis
- Department of Orthopaedic Surgery, University of Michigan Medical School, Ann Arbor
| | | | - Julie A Harning
- Department of Orthopaedic Surgery, University of Michigan Medical School, Ann Arbor
| | - Paul D DeWolf
- Department of Orthopaedic Surgery, University of Michigan Medical School, Ann Arbor
| | - Tarek A Makki
- Department of Orthopaedic Surgery, University of Michigan Medical School, Ann Arbor
| | - Asheesh Bedi
- Department of Orthopaedic Surgery, University of Michigan Medical School, Ann Arbor
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Rodino-Klapac LR, Janssen PML, Shontz KM, Canan B, Montgomery CL, Griffin D, Heller K, Schmelzer L, Handy C, Clark KR, Sahenk Z, Mendell JR, Kaspar BK. Micro-dystrophin and follistatin co-delivery restores muscle function in aged DMD model. Hum Mol Genet 2013; 22:4929-37. [PMID: 23863459 DOI: 10.1093/hmg/ddt342] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Pharmacologic strategies have provided modest improvement in the devastating muscle-wasting disease, Duchenne muscular dystrophy (DMD). Pre-clinical gene therapy studies have shown promise in the mdx mouse model; however, studies conducted after disease onset fall short of fully correcting muscle strength or protecting against contraction-induced injury. Here we examine the treatment effect on muscle physiology in aged dystrophic mice with significant disease pathology by combining two promising therapies: micro-dystrophin gene replacement and muscle enhancement with follistatin, a potent myostatin inhibitor. Individual treatments with micro-dystrophin and follistatin demonstrated marked improvement in mdx mice but were insufficient to fully restore muscle strength and response to injury to wild-type levels. Strikingly, when combined, micro-dystrophin/follistatin treatment restored force generation and conferred resistance to contraction-induced injury in aged mdx mice. Pre-clinical studies with miniature dystrophins have failed to demonstrate full correction of the physiological defects seen in mdx mice. Importantly, the addition of a muscle enhancement strategy with delivery of follistatin in combination with micro-dystrophin gene therapy completely restored resistance to eccentric contraction-induced injury and improved force. Eccentric contraction-induced injury is a pre-clinical parameter relevant to the exercise induced injury that occurs in DMD patients, and herein, we demonstrate compelling evidence for the therapeutic potential of micro-dystrophin/follistatin combinatorial therapy.
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49
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Giannesini B, Vilmen C, Amthor H, Bernard M, Bendahan D. Lack of myostatin impairs mechanical performance and ATP cost of contraction in exercising mouse gastrocnemius muscle in vivo. Am J Physiol Endocrinol Metab 2013; 305:E33-40. [PMID: 23632633 DOI: 10.1152/ajpendo.00651.2012] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Although it is well established that the lack of myostatin (Mstn) promotes skeletal muscle hypertrophy, the corresponding changes regarding force generation have been studied mainly in vitro and remain conflicting. Furthermore, the metabolic underpinnings of these changes are very poorly documented. To clarify this issue, we have investigated strictly noninvasively in vivo the impact of the lack of Mstn on gastrocnemius muscle function and energetics in Mstn-targeted knockout (Mstn-/-) mice using ¹H-magnetic resonance (MR) imaging and ³¹P-MR spectroscopy during maximal repeated isometric contractions induced by transcutaneous electrostimulation. In Mstn-/- animals, although body weight, gastrocnemius muscle volume, and absolute force were larger (+38, +118, and +34%, respectively) compared with wild-type (Mstn+/+) mice, specific force (calculated from MR imaging measurements) was significantly lower (-36%), and resistance to fatigue was decreased. Besides, Mstn deficiency did not affect phosphorylated compound concentrations and intracellular pH at rest but caused a large increase in ATP cost of contraction (up to +206% compared with Mstn+/+) throughout the stimulation period. Further, Mstn deficiency limits the shift toward oxidative metabolism during muscle activity despite the fact that oxidative ATP synthesis capacity was not altered. Our data demonstrate in vivo that the absence of Mstn impairs both mechanical performance and energy cost of contraction in hypertrophic muscle. These findings must be kept in mind when considering Mstn as a potential therapeutic target for increasing muscle mass in patients suffering from muscle-wasting disorders.
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Affiliation(s)
- Benoît Giannesini
- Aix-Marseille Université, Centre National de la Recherche Scientifique (CNRS), Centre de Résonance Magnétique Biologique et Médicale (CRMBM) UMR 7339, 13385, Marseille, France.
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Age-dependent alteration in muscle regeneration: the critical role of tissue niche. Biogerontology 2013; 14:273-92. [PMID: 23666344 PMCID: PMC3719007 DOI: 10.1007/s10522-013-9429-4] [Citation(s) in RCA: 82] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2013] [Accepted: 04/29/2013] [Indexed: 12/31/2022]
Abstract
Although adult skeletal muscle is composed of fully differentiated fibers, it retains the capacity to regenerate in response to injury and to modify its contractile and metabolic properties in response to changing demands. The major role in the growth, remodeling and regeneration is played by satellite cells, a quiescent population of myogenic precursor cells that reside between the basal lamina and plasmalemma and that are rapidly activated in response to appropriate stimuli. However, in pathologic conditions or during aging, the complete regenerative program can be precluded by fibrotic tissue formation and resulting in functional impairment of the skeletal muscle. Our study, along with other studies, demonstrated that although the regenerative program can also be impaired by the limited proliferative capacity of satellite cells, this limit is not reached during normal aging, and it is more likely that the restricted muscle repair program in aging is presumably due to missing signals that usually render the damaged muscle a permissive environment for regenerative activity.
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