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Sullivan BP, Collins BC, McMillin SL, Toussaint E, Stein CZ, Spangenburg EE, Lowe DA. Ablation of skeletal muscle estrogen receptor alpha impairs contractility in male mice. J Appl Physiol (1985) 2024; 136:764-773. [PMID: 38328824 DOI: 10.1152/japplphysiol.00714.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2023] [Accepted: 02/02/2024] [Indexed: 02/09/2024] Open
Abstract
Estradiol and estrogen receptor α (ERα) have been shown to be important for the maintenance of skeletal muscle strength in females; however, little is known about the roles of estradiol and ERα in male muscle. The purpose of this study was to determine if skeletal muscle ERα is required for optimal contractility in male mice. We hypothesize that reduced ERα in skeletal muscle impairs contractility in male mice. Skeletal muscle-specific knockout (skmERαKO) male mice exhibited reduced strength across multiple muscles and several contractile parameters related to force generation and kinetics compared with wild-type littermates (skmERαWT). Isolated EDL muscle-specific isometric tetanic force, peak twitch force, peak concentric and peak eccentric forces, as well as the maximal rates of force development and relaxation were 11%-21% lower in skmERαKO compared with skmERαWT mice. In contrast, isolated soleus muscles from skmERαKO mice were not affected. In vivo peak torque of the anterior crural muscles was 20% lower in skmERαKO compared with skmERαWT mice. Muscle masses, contractile protein contents, fiber types, phosphorylation of the myosin regulatory light chain, and caffeine-elicited force did not differ between muscles of skmERαKO and skmERαWT mice, suggesting that strength deficits were not due to size, composition, or calcium release components of muscle contraction. These results indicate that in male mice, reduced skeletal muscle ERα blunts contractility to a magnitude similar to that previously reported in females; however, the mechanism may be sexually dimorphic.NEW & NOTEWORTHY We comprehensively measured in vitro and in vivo contractility of leg muscles with reduced estrogen receptor α (ERα) in male mice and reported that force generation and contraction kinetics are impaired. In contrast to findings in females, phosphorylation of myosin regulatory light chain cannot account for low force production in male skeletal muscle ERα knockout mice. These results indicate that ERα is required for optimal contractility in males and females but via sexually dimorphic means.
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Affiliation(s)
- Brian P Sullivan
- Division of Physical Therapy and Rehabilitation Science, Department of Family Medicine and Community Health, University of Minnesota, Minneapolis, Minnesota, United States
| | - Brittany C Collins
- Division of Physical Therapy and Rehabilitation Science, Department of Family Medicine and Community Health, University of Minnesota, Minneapolis, Minnesota, United States
| | - Shawna L McMillin
- Division of Physical Therapy and Rehabilitation Science, Department of Family Medicine and Community Health, University of Minnesota, Minneapolis, Minnesota, United States
| | - Elise Toussaint
- Division of Physical Therapy and Rehabilitation Science, Department of Family Medicine and Community Health, University of Minnesota, Minneapolis, Minnesota, United States
| | - Clara Z Stein
- Division of Physical Therapy and Rehabilitation Science, Department of Family Medicine and Community Health, University of Minnesota, Minneapolis, Minnesota, United States
| | - Espen E Spangenburg
- Department of Physiology, Brody School of Medicine, East Carolina Diabetes and Obesity Institute, East Carolina University, Greenville, North Carolina, United States
| | - Dawn A Lowe
- Division of Physical Therapy and Rehabilitation Science, Department of Family Medicine and Community Health, University of Minnesota, Minneapolis, Minnesota, United States
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Ahmed Z, Tahmin CI, Tahsin CT, Michopoulos V, Mohamed A, Wattero R, Albott S, Cullen KR, Lowe DA, Osborn J, Fonkoue IT. Higher arterial stiffness and blunted vagal control of the heart in young women with compared to without a clinical diagnosis of PTSD. Clin Auton Res 2024; 34:165-175. [PMID: 38324188 PMCID: PMC10947824 DOI: 10.1007/s10286-024-01014-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2023] [Accepted: 01/08/2024] [Indexed: 02/08/2024]
Abstract
PURPOSE Young women are typically thought to be protected from cardiovascular disease (CVD) before menopause. However, posttraumatic stress disorder (PTSD) increases CVD risk in women by up to threefold. Data in predominantly male cohorts point to physiological mechanisms such as vascular and autonomic derangements as contributing to increased CVD risk. The purpose of the study reported here was to determine whether young women diagnosed with PTSD, compared to those without, present with arterial stiffness and impaired autonomic control of the heart. METHODS A total of 73 healthy young women, ranging in age from 18 to 40 years, with a history of trauma exposure were included in this study, 32 with and 41 without a clinical PTSD diagnosis. We measured resting pulse wave velocity (PWV), central hemodynamics, augmentation pressure and augmentation index (AI) via pulse wave analysis using applanation tonometry. Heart rate variability was also assessed via peripheral arterial tone. RESULTS In comparison to controls, women with PTSD showed higher central arterial pressure (mean ± standard deviation: systolic blood pressure 104 ± 8 vs. 97 ± 8 mmHg, p < 0.001; diastolic blood pressure 72 ± 7 vs. 67 ± 7 mmHg, p = 0.003), PWV (6 ± 0.3 vs. 5 ± 0.6 m/s, p < 0.001) and AI (22 ± 13 vs. 15 ± 12%, p = 0.007) but lower standard deviation of normal-to-normal intervals (SDNN; 44 ± 17 vs. 54 ± 18 ms, p = 0.005) and root mean square of successive differences between normal heartbeats (RMSSD; 37 ± 17 vs. 51 ± 22 ms, p = 0.002). CONCLUSION PTSD in young women is associated with higher brachial and central pressures, increased arterial stiffness and blunted parasympathetic control of the heart. These findings illustrate potential mechanisms underlying high risk for CVD in young women with PTSD, suggesting possible treatment targets for this at-risk group.
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Affiliation(s)
- Zynab Ahmed
- Divisions of Physical Therapy and Rehabilitation Science, Department of Rehabilitation Medicine, University of Minnesota Medical School, 420 Delaware St. SE (MMC 388), Minneapolis, MN, USA
- Division of Health Policy and Management, School of Public Health, Minneapolis, MN, USA
| | - Chowdhury Ibtida Tahmin
- Divisions of Physical Therapy and Rehabilitation Science, Department of Rehabilitation Medicine, University of Minnesota Medical School, 420 Delaware St. SE (MMC 388), Minneapolis, MN, USA
| | - Chowdhury Tasnova Tahsin
- Divisions of Physical Therapy and Rehabilitation Science, Department of Rehabilitation Medicine, University of Minnesota Medical School, 420 Delaware St. SE (MMC 388), Minneapolis, MN, USA
| | - Vasiliki Michopoulos
- Department of Psychiatry and Behavioral Sciences, Emory University School of Medicine, Atlanta, GA, USA
| | - Azhaar Mohamed
- Divisions of Physical Therapy and Rehabilitation Science, Department of Rehabilitation Medicine, University of Minnesota Medical School, 420 Delaware St. SE (MMC 388), Minneapolis, MN, USA
| | - Redeat Wattero
- Divisions of Physical Therapy and Rehabilitation Science, Department of Rehabilitation Medicine, University of Minnesota Medical School, 420 Delaware St. SE (MMC 388), Minneapolis, MN, USA
| | - Sophia Albott
- Department of Psychiatry, University of Minnesota Medical School, Minneapolis, MN, USA
- Mental Health Service Line, Minneapolis VA Health Care System, Minneapolis, MN, USA
| | - Kathryn R Cullen
- Department of Psychiatry, University of Minnesota Medical School, Minneapolis, MN, USA
| | - Dawn A Lowe
- Divisions of Physical Therapy and Rehabilitation Science, Department of Rehabilitation Medicine, University of Minnesota Medical School, 420 Delaware St. SE (MMC 388), Minneapolis, MN, USA
| | - John Osborn
- Department of Surgery, University of Minnesota Medical School, Minneapolis, MN, USA
| | - Ida T Fonkoue
- Divisions of Physical Therapy and Rehabilitation Science, Department of Rehabilitation Medicine, University of Minnesota Medical School, 420 Delaware St. SE (MMC 388), Minneapolis, MN, USA.
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Gilmer G, Hettinger ZR, Tuakli-Wosornu Y, Skidmore E, Silver JK, Thurston RC, Lowe DA, Ambrosio F. Publisher Correction: Female aging: when translational models don't translate. Nat Aging 2024; 4:164. [PMID: 38177332 DOI: 10.1038/s43587-023-00561-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2024]
Affiliation(s)
- Gabrielle Gilmer
- Discovery Center for Musculoskeletal Recovery, Schoen Adams Research Institute at Spaulding Rehabilitation, Boston, MA, USA
- Department of Physical Medicine and Rehabilitation, Spaulding Rehabilitation Hospital, Charlestown, MA, USA
- Medical Scientist Training Program, School of Medicine, University of Pittsburgh, Pittsburgh, PA, USA
- Cellular and Molecular Pathology Graduate Program, University of Pittsburgh, Pittsburgh, PA, USA
| | - Zachary R Hettinger
- Discovery Center for Musculoskeletal Recovery, Schoen Adams Research Institute at Spaulding Rehabilitation, Boston, MA, USA
- Department of Physical Medicine and Rehabilitation, Spaulding Rehabilitation Hospital, Charlestown, MA, USA
- Department of Physical Medicine & Rehabilitation, Harvard Medical School, Boston, MA, USA
- Department of Geriatric Medicine, University of Pittsburgh, Pittsburgh, PA, USA
| | - Yetsa Tuakli-Wosornu
- Department of Social and Behavioral Sciences, Yale School of Public Health, Yale University, New Haven, CT, USA
- Department of Physical Medicine and Rehabilitation, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Elizabeth Skidmore
- Department of Occupational Therapy, School of Health and Rehabilitation Sciences, University of Pittsburgh, Pittsburgh, PA, USA
| | - Julie K Silver
- Department of Physical Medicine and Rehabilitation, Spaulding Rehabilitation Hospital, Charlestown, MA, USA
- Department of Physical Medicine & Rehabilitation, Harvard Medical School, Boston, MA, USA
- Department of Physical Medicine and Rehabilitation, Massachusetts General Hospital, Boston, MA, USA
- Department of Physical Medicine and Rehabilitation, Brigham and Women's Hospital, Boston, MA, USA
| | - Rebecca C Thurston
- Department of Psychiatry, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Dawn A Lowe
- Divisions of Rehabilitation Science and Physical Therapy, Department of Rehabilitation Medicine, University of Minnesota, Minneapolis, MN, USA
| | - Fabrisia Ambrosio
- Discovery Center for Musculoskeletal Recovery, Schoen Adams Research Institute at Spaulding Rehabilitation, Boston, MA, USA.
- Department of Physical Medicine and Rehabilitation, Spaulding Rehabilitation Hospital, Charlestown, MA, USA.
- Department of Physical Medicine & Rehabilitation, Harvard Medical School, Boston, MA, USA.
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Gilmer G, Hettinger ZR, Tuakli-Wosornu Y, Skidmore E, Silver JK, Thurston RC, Lowe DA, Ambrosio F. Female aging: when translational models don't translate. Nat Aging 2023; 3:1500-1508. [PMID: 38052933 PMCID: PMC11099540 DOI: 10.1038/s43587-023-00509-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2023] [Accepted: 09/25/2023] [Indexed: 12/07/2023]
Abstract
For many pathologies associated with aging, female patients present with higher morbidity and more frequent adverse events from treatments compared to male patients. While preclinical models are the foundation of our mechanistic understanding of age-related diseases, the most common models fail to recapitulate archetypical female aging trajectories. For example, while over 70% of the top age-related diseases are influenced by the systemic effects of reproductive senescence, we found that preclinical studies that include menopausal phenotypes modeling those seen in humans make up <1% of published aging biology research. The long-term impacts of pregnancy, birthing and breastfeeding are also typically omitted from preclinical work. In this Perspective, we summarize limitations in the most commonly used aging models, and we provide recommendations for better incorporating menopause, pregnancy and other considerations of sex in vivo and in vitro. Lastly, we outline action items for aging biology researchers, journals, funding agencies and animal providers to address this gap.
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Affiliation(s)
- Gabrielle Gilmer
- Discovery Center for Musculoskeletal Recovery, Schoen Adams Research Institute at Spaulding Rehabilitation, Boston, MA, USA
- Department of Physical Medicine and Rehabilitation, Spaulding Rehabilitation Hospital, Charlestown, MA, USA
- Medical Scientist Training Program, School of Medicine, University of Pittsburgh, Pittsburgh, PA, USA
- Cellular and Molecular Pathology Graduate Program, University of Pittsburgh, Pittsburgh, PA, USA
| | - Zachary R Hettinger
- Discovery Center for Musculoskeletal Recovery, Schoen Adams Research Institute at Spaulding Rehabilitation, Boston, MA, USA
- Department of Physical Medicine and Rehabilitation, Spaulding Rehabilitation Hospital, Charlestown, MA, USA
- Department of Physical Medicine & Rehabilitation, Harvard Medical School, Boston, MA, USA
- Department of Geriatric Medicine, University of Pittsburgh, Pittsburgh, PA, USA
| | - Yetsa Tuakli-Wosornu
- Department of Social and Behavioral Sciences, Yale School of Public Health, Yale University, New Haven, CT, USA
- Department of Physical Medicine and Rehabilitation, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Elizabeth Skidmore
- Department of Occupational Therapy, School of Health and Rehabilitation Sciences, University of Pittsburgh, Pittsburgh, PA, USA
| | - Julie K Silver
- Department of Physical Medicine and Rehabilitation, Spaulding Rehabilitation Hospital, Charlestown, MA, USA
- Department of Physical Medicine & Rehabilitation, Harvard Medical School, Boston, MA, USA
- Department of Physical Medicine and Rehabilitation, Massachusetts General Hospital, Boston, MA, USA
- Department of Physical Medicine and Rehabilitation, Brigham and Women's Hospital, Boston, MA, USA
| | - Rebecca C Thurston
- Department of Psychiatry, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Dawn A Lowe
- Divisions of Rehabilitation Science and Physical Therapy, Department of Rehabilitation Medicine, University of Minnesota, Minneapolis, MN, USA
| | - Fabrisia Ambrosio
- Discovery Center for Musculoskeletal Recovery, Schoen Adams Research Institute at Spaulding Rehabilitation, Boston, MA, USA.
- Department of Physical Medicine and Rehabilitation, Spaulding Rehabilitation Hospital, Charlestown, MA, USA.
- Department of Physical Medicine & Rehabilitation, Harvard Medical School, Boston, MA, USA.
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Baumann CW, Deane CS, Etheridge T, Szewczyk NJ, Willis CRG, Lowe DA. Adaptability to eccentric exercise training is diminished with age in female mice. J Appl Physiol (1985) 2023; 135:1135-1145. [PMID: 37823203 PMCID: PMC10979833 DOI: 10.1152/japplphysiol.00428.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2023] [Revised: 10/02/2023] [Accepted: 10/03/2023] [Indexed: 10/13/2023] Open
Abstract
The ability of skeletal muscle to adapt to eccentric contractions has been suggested to be blunted in older muscle. If eccentric exercise is to be a safe and efficient training mode for older adults, preclinical studies need to establish if older muscle can effectively adapt and if not, determine the molecular signatures that are causing this impairment. The purpose of this study was to quantify the extent age impacts functional adaptations of muscle and identify genetic signatures associated with adaptation (or lack thereof). The anterior crural muscles of young (4 mo) and older (28 mo) female mice performed repeated bouts of eccentric contractions in vivo (50 contractions/wk for 5 wk) and isometric torque was measured across the initial and final bouts. Transcriptomics was completed by RNA-sequencing 1 wk following the fifth bout to identify common and differentially regulated genes. When torques post eccentric contractions were compared after the first and fifth bouts, young muscle exhibited a robust ability to adapt, increasing isometric torque 20%-36%, whereas isometric torque of older muscle decreased up to 18% (P ≤ 0.047). Using differential gene expression, young and older muscles shared some common transcriptional changes in response to eccentric exercise training, whereas other transcripts appeared to be age dependent. That is, the ability to express particular genes after repeated bouts of eccentric contractions was not the same between ages. These molecular signatures may reveal, in part, why older muscles do not appear to be as adaptive to exercise training as young muscles.NEW & NOTEWORTHY The ability to adapt to exercise training may help prevent and combat sarcopenia. Here, we demonstrate young mouse muscles get stronger whereas older mouse muscles become weaker after repeated bouts of eccentric contractions, and that numerous genes were differentially expressed between age groups following training. These results highlight that molecular and functional plasticity is not fixed in skeletal muscle with advancing age, and the ability to handle or cope with physical stress may be impaired.
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Affiliation(s)
- Cory W Baumann
- Ohio Musculoskeletal and Neurological Institute (OMNI), Ohio University, Athens, Ohio, United States
- Department of Biomedical Sciences, Heritage College of Osteopathic Medicine, Ohio University, Athens, Ohio, United States
| | - Colleen S Deane
- Faculty of Life Sciences, Department of Public Health and Sport Sciences, University of Exeter, Exeter, United Kingdom
- Faculty of Medicine, Department of Human Development & Health, University of Southampton, Southampton General Hospital, Southampton, United Kingdom
| | - Timothy Etheridge
- Faculty of Life Sciences, Department of Public Health and Sport Sciences, University of Exeter, Exeter, United Kingdom
| | - Nathaniel J Szewczyk
- Ohio Musculoskeletal and Neurological Institute (OMNI), Ohio University, Athens, Ohio, United States
- Department of Biomedical Sciences, Heritage College of Osteopathic Medicine, Ohio University, Athens, Ohio, United States
| | - Craig R G Willis
- Ohio Musculoskeletal and Neurological Institute (OMNI), Ohio University, Athens, Ohio, United States
- Department of Biomedical Sciences, Heritage College of Osteopathic Medicine, Ohio University, Athens, Ohio, United States
- Faculty of Life Sciences, School of Chemistry and Biosciences, University of Bradford, Bradford, United Kingdom
| | - Dawn A Lowe
- Divisions of Rehabilitation Science and Physical Therapy, Department of Rehabilitation Medicine, Medical School, University of Minnesota, Minneapolis, Minnesota, United States
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Peyton MP, Yang TY, Higgins L, Markowski TW, Murray K, Vue C, Parker LL, Lowe DA. Natural aging and ovariectomy induces parallel phosphoproteomic alterations in skeletal muscle of female mice. Aging (Albany NY) 2023; 15:7362-7380. [PMID: 37580837 PMCID: PMC10457050 DOI: 10.18632/aging.204959] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2022] [Accepted: 07/24/2023] [Indexed: 08/16/2023]
Abstract
The loss of skeletal muscle strength mid-life in females is associated with the decline of estrogen. Here, we questioned how estrogen deficiency might impact the overall skeletal muscle phosphoproteome after contraction, as force production induces phosphorylation of several muscle proteins. Phosphoproteomic analyses of the tibialis anterior muscle after contraction in two mouse models of estrogen deficiency, ovariectomy (Ovariectomized (Ovx) vs. Sham) and natural aging-induced ovarian senescence (Older Adult (OA) vs. Young Adult (YA)), identified a total of 2,593 and 3,507 phosphopeptides in Ovx/Sham and OA/YA datasets, respectively. Further analysis of estrogen deficiency-associated proteins and phosphosites identified 66 proteins and 21 phosphosites from both datasets. Of these, 4 estrogen deficiency-associated proteins and 4 estrogen deficiency-associated phosphosites were significant and differentially phosphorylated or regulated, respectively. Comparative analyses between Ovx/Sham and OA/YA using Ingenuity Pathway Analysis (IPA) found parallel patterns of inhibition and activation across IPA-defined canonical signaling pathways and physiological functional analysis, which were similarly observed in downstream GO, KEGG, and Reactome pathway overrepresentation analysis pertaining to muscle structural integrity and contraction, including AMPK and calcium signaling. IPA Upstream regulator analysis identified MAPK1 and PRKACA as candidate kinases and calcineurin as a candidate phosphatase sensitive to estrogen. Our findings highlight key molecular signatures and pathways in contracted muscle suggesting that the similarities identified across both datasets could elucidate molecular mechanisms that may contribute to skeletal muscle strength loss due to estrogen deficiency.
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Affiliation(s)
- Mina P. Peyton
- Department of Rehabilitation Medicine, Division of Rehabilitation Science, University of Minnesota – Twin Cities, Minneapolis, MN 55455, USA
- Department of Computer Science, Bioinformatics and Computational Biology Program, University of Minnesota, Minneapolis, MN 55455, USA
| | - Tzu-Yi Yang
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota – Twin Cities, Minneapolis, MN 55455, USA
| | - LeeAnn Higgins
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota – Twin Cities, Minneapolis, MN 55455, USA
| | - Todd W. Markowski
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota – Twin Cities, Minneapolis, MN 55455, USA
| | - Kevin Murray
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota – Twin Cities, Minneapolis, MN 55455, USA
| | - Cha Vue
- Department of Rehabilitation Medicine, Division of Rehabilitation Science, University of Minnesota – Twin Cities, Minneapolis, MN 55455, USA
| | - Laurie L. Parker
- Department of Computer Science, Bioinformatics and Computational Biology Program, University of Minnesota, Minneapolis, MN 55455, USA
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota – Twin Cities, Minneapolis, MN 55455, USA
| | - Dawn A. Lowe
- Department of Rehabilitation Medicine, Division of Rehabilitation Science, University of Minnesota – Twin Cities, Minneapolis, MN 55455, USA
- Department of Rehabilitation Medicine, Division of Physical Therapy, University of Minnesota – Twin Cities, Minneapolis, MN 55455, USA
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7
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Le G, Baumann CW, Warren GL, Lowe DA. In vivo potentiation of muscle torque is enhanced in female mice through estradiol-estrogen receptor signaling. J Appl Physiol (1985) 2023; 134:722-730. [PMID: 36735234 PMCID: PMC10027088 DOI: 10.1152/japplphysiol.00731.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2022] [Revised: 01/13/2023] [Accepted: 02/02/2023] [Indexed: 02/04/2023] Open
Abstract
Estradiol affects several properties of skeletal muscle in females including strength. Here, we developed an approach to measure in vivo posttetanic twitch potentiation (PTP) of the anterior crural muscles of anesthetized mice and tested the hypothesis that 17β-estradiol (E2) enhances PTP through estrogen receptor (ER) signaling. Peak torques of potentiated twitches were ∼40%-60% greater than those of unpotentiated twitches and such PTP was greater in ovary-intact mice, or ovariectomized (Ovx) mice treated with E2, compared with Ovx mice (P ≤ 0.047). PTP did not differ between mice with and without ERα ablated in skeletal muscle fibers (P = 0.347). Treatment of ovary-intact and Ovx mice with ERβ antagonist and agonist (PHTPP and DPN, respectively) did not affect PTP (P ≥ 0.258). Treatment with G1, an agonist of the G protein-coupled estrogen receptor (GPER), significantly increased PTP in Ovx mice from 41 ± 10% to 66 ± 21% (means ± SD; P = 0.034). Collectively, these data indicate that E2 signals through GPER, and not ERα or ERβ, in skeletal muscles of female mice to augment an in vivo parameter of strength, namely, PTP.NEW & NOTEWORTHY A novel in vivo approach was developed to measure potentiation of skeletal muscle torque in female mice and highlight another parameter of strength that is impacted by estradiol. The enhancement of PTP by estradiol is mediated distinctively through the G-protein estrogen receptor, GPER.
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Affiliation(s)
- Gengyun Le
- Division of Rehabilitation Science and Physical Therapy, Department of Rehabilitation Medicine, University of Minnesota Medical School, Minneapolis, Minnesota, United States
| | - Cory W Baumann
- Division of Rehabilitation Science and Physical Therapy, Department of Rehabilitation Medicine, University of Minnesota Medical School, Minneapolis, Minnesota, United States
| | - Gordon L Warren
- Department of Physical Therapy, Georgia State University, Atlanta, Georgia, United States
| | - Dawn A Lowe
- Division of Rehabilitation Science and Physical Therapy, Department of Rehabilitation Medicine, University of Minnesota Medical School, Minneapolis, Minnesota, United States
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Peyton MP, Yang TY, Higgins L, Markowski TW, Vue C, Parker LL, Lowe DA. Global phosphoproteomic profiling of skeletal muscle in ovarian hormone-deficient mice. Physiol Genomics 2022; 54:417-432. [PMID: 36062884 PMCID: PMC9639773 DOI: 10.1152/physiolgenomics.00104.2022] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2022] [Revised: 08/05/2022] [Accepted: 08/30/2022] [Indexed: 11/22/2022] Open
Abstract
Protein phosphorylation is important in skeletal muscle development, growth, regeneration, and contractile function. Alterations in the skeletal muscle phosphoproteome due to aging have been reported in males; however, studies in females are lacking. We have demonstrated that estrogen deficiency decreases muscle force, which correlates with decreased myosin regulatory light chain phosphorylation. Thus, we questioned whether the decline of estrogen in females that occurs with aging might alter the skeletal muscle phosphoproteome. C57BL/6J female mice (6 mo) were randomly assigned to a sham-operated (Sham) or ovariectomy (Ovx) group to investigate the effects of estrogen deficiency on skeletal muscle protein phosphorylation in a resting, noncontracting condition. After 16 wk of estrogen deficiency, the tibialis anterior muscle was dissected and prepped for label-free nano-liquid chromatography-tandem mass spectrometry phosphoproteomic analysis. We identified 4,780 phosphopeptides in tibialis anterior muscles of ovariectomized (Ovx) and Sham-operated (Sham) control mice. Further analysis revealed 647 differentially regulated phosphopeptides (Benjamini-Hochberg adjusted P value < 0.05 and 1.5-fold change ratio) that corresponded to 130 proteins with 22 proteins differentially phosphorylated (3 unique to Ovx, 2 unique to Sham, 6 upregulated, and 11 downregulated). Differentially phosphorylated proteins associated with the sarcomere, cytoplasm, and metabolic and calcium signaling pathways were identified. Our work provides the first global phosphoproteomic analysis in females and how estrogen deficiency impacts the skeletal muscle phosphoproteome.
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Affiliation(s)
- Mina P Peyton
- Division of Rehabilitation Science, Department of Rehabilitation Medicine, University of Minnesota, Twin Cities, Minneapolis, Minnesota
- Department of Computer Science, Bioinformatics and Computational Biology Program, University of Minnesota, Minneapolis, Minnesota
| | - Tzu-Yi Yang
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Twin Cities, Minneapolis, Minnesota
| | - LeeAnn Higgins
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Twin Cities, Minneapolis, Minnesota
| | - Todd W Markowski
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Twin Cities, Minneapolis, Minnesota
| | - Cha Vue
- Division of Rehabilitation Science, Department of Rehabilitation Medicine, University of Minnesota, Twin Cities, Minneapolis, Minnesota
| | - Laurie L Parker
- Department of Computer Science, Bioinformatics and Computational Biology Program, University of Minnesota, Minneapolis, Minnesota
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Twin Cities, Minneapolis, Minnesota
| | - Dawn A Lowe
- Division of Rehabilitation Science, Department of Rehabilitation Medicine, University of Minnesota, Twin Cities, Minneapolis, Minnesota
- Division of Physical Therapy, Department of Rehabilitation Medicine, University of Minnesota, Twin Cities, Minneapolis, Minnesota
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Norton A, Thieu K, Baumann CW, Lowe DA, Mansky KC. Estrogen regulation of myokines that enhance osteoclast differentiation and activity. Sci Rep 2022; 12:15900. [PMID: 36151243 PMCID: PMC9508086 DOI: 10.1038/s41598-022-19438-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2022] [Accepted: 08/29/2022] [Indexed: 11/24/2022] Open
Abstract
Osteoporosis and sarcopenia are maladies of aging that negatively affect more women than men. In recent years, it has become apparent that bone and muscle are coupled not only mechanically as muscle pulls on bone, but also at a higher level with myokines, biochemical and molecular signaling occurring between cells of the two tissues. However, how estrogen deficiency in females impacts the chemical crosstalk between bone and muscle cells is not understood. We hypothesize that changes in estrogen signaling alters myokine expression and intensifies bone loss in women. In our present study, we demonstrate that conditioned media from ovariectomized or skeletal muscle deficient in estrogen receptor α (ERα) expression enhances osteoclast differentiation and activity. Using a cytokine array, we identified myokines that have altered expressions in response to loss of estrogen signaling in muscle. Lastly, we demonstrate that conditional deletion of ERα in skeletal muscle results in osteopenia due to an increase in the osteoclast surface per bone surface. Our results suggest that estrogen signaling modulates expression of myokines that regulate osteoclast differentiation and activity.
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Affiliation(s)
- Andrew Norton
- Division of Orthodontics, Department of Developmental and Surgical Sciences, University of Minnesota School of Dentistry, 515 Delaware St SE, Minneapolis, MN, 55455, USA
| | - Kathleen Thieu
- Division of Periodontology, Department of Developmental and Surgical Sciences, University of Minnesota School of Dentistry, Minneapolis, MN, 55455, USA
| | - Cory W Baumann
- Ohio Musculoskeletal and Neurological Institute (OMNI), Department of Biomedical Sciences, Ohio University, Athens, OH, 45701, USA.,Divisions of Rehabilitation Science and Physical Therapy, Department of Rehabilitation Medicine, University of Minnesota Medical School, Minneapolis, MN, 55455, USA
| | - Dawn A Lowe
- Divisions of Rehabilitation Science and Physical Therapy, Department of Rehabilitation Medicine, University of Minnesota Medical School, Minneapolis, MN, 55455, USA.
| | - Kim C Mansky
- Division of Orthodontics, Department of Developmental and Surgical Sciences, University of Minnesota School of Dentistry, 515 Delaware St SE, Minneapolis, MN, 55455, USA.
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Abstract
Twitch force potentiation of fast-twitch skeletal muscle is produced by repetitive stimulation that can be achieved from either (1) the staircase effect (continual low frequency stimulation) or (2) post-tetanic potentiation (a 1-2 s high-frequency tetanic stimulation). Previous studies examining twitch force potentiation have been conducted in vitro and shown that it is related to phosphorylation of myosin regulatory light chain (pRLC). We previously found, in vitro, reduced potentiation of twitch force and decreased pRLC in ovariectomized (Ovx, estrogen-deficient) compared with sham-operated (estrogen-replete) mice. Thus, we questioned whether this phenomenon occurred in vivo and whether age and sex would affect the potentiation of twitch force. Using an in vivo post-tetanic potentiation method (one twitch contraction followed by a tetanic contraction-100 Hz for 1,000 ms with 0.01 ms pulses, and two post-tetanic twitch contractions), we investigated twitch torque potentiation in C57BL/6 young and old, male and female mice. There were significant main effects of sex (P < 0.001) and age (P < 0.001) on body mass and significant main effects of sex (P < 0.001) on tibialis anterior and extensor digitorum longus muscle masses, with males and aged being relatively greater. Analysis of twitch torque using a three-way ANOVA across time, age, and sex showed a significant main effect of time (pre < post; P < 0.001), time × age (P = 0.038), and time × sex (P = 0.028), indicating potentiation occurred in young and old, males and females. Analysis of twitch torque potentiation (percent increase) using a two-way ANOVA revealed a significant main effect of age (young = 45.16 ± 2.04 versus old = 27.88 ± 9.96; P < 0.001) with no effect of sex (P = 0.215). In summary, enhanced generation of twitch force of skeletal muscle using a post-tetanic potentiation method does occur in vivo and is affected by age but not sex, as there is greater twitch torque potentiation in young than old mice.
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Affiliation(s)
- Mina P Peyton
- Division of Rehabilitation Science, Department of Rehabilitation Medicine, University of Minnesota, Minneapolis, MN
| | - Dawn A Lowe
- Division of Rehabilitation Science, Department of Rehabilitation Medicine, University of Minnesota, Minneapolis, MN
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Baumann CW, Ingalls CP, Lowe DA. Mechanisms of weakness in Mdx muscle following in vivo eccentric contractions. J Muscle Res Cell Motil 2022; 43:63-72. [PMID: 35445349 DOI: 10.1007/s10974-022-09617-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2021] [Accepted: 03/30/2022] [Indexed: 02/03/2023]
Abstract
Skeletal muscle of the dystrophin-deficient mdx mouse is hypersensitive to eccentric (ECC) contraction-induced strength loss due to plasmalemmal electrical dysfunction. Despite plasmalemmal inexcitability being a logical mechanism responsible for weakness, it remains unclear if processes up- and/or down-stream remain functionally intact in injured mdx muscle. The purpose of this study was to analyze additional processes necessary for excitation-contraction coupling that are potentially disrupted by ECC contractions. Anterior crural muscles (tibialis anterior, extensor digitorum longus [EDL], and extensor hallucis muscles) of wildtype (WT) and mdx mice were injured in vivo with 50 ECC contractions and torque was measured immediately before and after the contraction bout. Following the in vivo assessment, EDL ex vivo isometric and caffeine forces were analyzed. In vivo isometric torque and ex vivo force in WT muscle were reduced 38 and 30% (p < 0.001), while caffeine force was also reduced (p = 0.021), albeit to a lesser degree (9%). In contrast, in vivo isometric torque, ex vivo isometric force and ex vivo caffeine-induced force were all reduced 56-67% (p < 0.001) in mdx muscle and did not differ from one another (p = 0.114). Disproportional reductions in isometric strength and caffeine-induced force confirm that ECC contractions uncoupled the plasmalemma from the ryanodine receptors (RyRs) in WT muscle. In mdx muscle, the proportional reductions in isometric strength and caffeine-induced force following ECC contractions reveal that dysfunction occurs at and/or distal to the RyRs immediately post-injury. Thus, weakness in injured mdx muscle cannot be isolated to one mechanism, rather several steps of muscle contraction are disrupted.
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Affiliation(s)
- Cory W Baumann
- Ohio Musculoskeletal and Neurological Institute (OMNI), Department of Biomedical Sciences, Ohio University, Athens, OH, USA.
| | - Christopher P Ingalls
- Department of Kinesiology and Health, Georgia State University, Atlanta, Georgia, USA
| | - Dawn A Lowe
- Division of Rehabilitation Science, Division of Physical Therapy, Department of Rehabilitation Medicine, University of Minnesota, Minneapolis, Minnesota, USA
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12
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Larson AA, Shams AS, McMillin SL, Sullivan BP, Vue C, Roloff ZA, Batchelor E, Kyba M, Lowe DA. Estradiol deficiency reduces the satellite cell pool by impairing cell cycle progression. Am J Physiol Cell Physiol 2022; 322:C1123-C1137. [PMID: 35442828 PMCID: PMC9169829 DOI: 10.1152/ajpcell.00429.2021] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2021] [Revised: 03/31/2022] [Accepted: 04/17/2022] [Indexed: 12/22/2022]
Abstract
The size of the satellite cell pool is reduced in estradiol (E2)-deficient female mice and humans. Here, we use a combination of in vivo and in vitro approaches to identify mechanisms, whereby E2 deficiency impairs satellite cell maintenance. By measuring satellite cell numbers in mice at several early time points postovariectomy (Ovx), we determine that satellite cell numbers decline by 33% between 10 and 14 days post-Ovx in tibialis anterior and gastrocnemius muscles. At 14 days post-Ovx, we demonstrate that satellite cells have a reduced propensity to transition from G0/G1 to S and G2/M phases, compared with cells from ovary-intact mice, associated with changes in two key satellite cell cycle regulators, ccna2 and p16INK4a. Further, freshly isolated satellite cells treated with E2 in vitro have 62% greater cell proliferation and require less time to complete the first division. Using clonal and differentiation assays, we measured 69% larger satellite cell colonies and enhanced satellite cell-derived myoblast differentiation with E2 treatment compared with vehicle-treated cells. Together, these results identify a novel mechanism for preservation of the satellite cell pool by E2 via promotion of satellite cell cycling.
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Affiliation(s)
- Alexie A Larson
- Department of Integrative Biology and Physiology, Medical School, University of Minnesota, Minneapolis, Minnesota
| | - Ahmed S Shams
- Lillehei Heart Institute, Medical School, University of Minnesota, Minneapolis, Minnesota
- Department of Pediatrics, Medical School, University of Minnesota, Minneapolis, Minnesota
- Human Anatomy and Embryology Department, Faculty of Medicine, Suez Canal University, Ismailia, Egypt
| | - Shawna L McMillin
- Divisions of Rehabilitation Science and Physical Therapy, Department of Rehabilitation Medicine, Medical School, University of Minnesota, Minneapolis, Minnesota
| | - Brian P Sullivan
- Divisions of Rehabilitation Science and Physical Therapy, Department of Rehabilitation Medicine, Medical School, University of Minnesota, Minneapolis, Minnesota
| | - Cha Vue
- Divisions of Rehabilitation Science and Physical Therapy, Department of Rehabilitation Medicine, Medical School, University of Minnesota, Minneapolis, Minnesota
| | - Zachery A Roloff
- Divisions of Rehabilitation Science and Physical Therapy, Department of Rehabilitation Medicine, Medical School, University of Minnesota, Minneapolis, Minnesota
| | - Eric Batchelor
- Department of Integrative Biology and Physiology, Medical School, University of Minnesota, Minneapolis, Minnesota
| | - Michael Kyba
- Lillehei Heart Institute, Medical School, University of Minnesota, Minneapolis, Minnesota
- Department of Pediatrics, Medical School, University of Minnesota, Minneapolis, Minnesota
| | - Dawn A Lowe
- Divisions of Rehabilitation Science and Physical Therapy, Department of Rehabilitation Medicine, Medical School, University of Minnesota, Minneapolis, Minnesota
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Abstract
PURPOSE The ability of skeletal muscle to adapt to eccentric (ECC) contraction-induced injury is known as the repeated bout effect (RBE). Despite the RBE being a well-established phenomenon observed in skeletal muscle, cellular and molecular events particularly those at the membranes that contribute to the adaptive potential of muscle have yet to be established. Therefore, the purpose of this study was to examine how membrane-associated proteins respond to the RBE. METHODS Anterior crural muscles of C57BL/6 female mice (3-5 months) were subjected to repeated bouts of in vivo ECCs, with isometric torque being measured immediately before and after injury. A total of six bouts were completed with 7 d between each bout. Protein content of dystrophin, β-sarcoglycan, and junctophilin were then assessed via immunoblotting in injured and uninjured muscles. RESULTS When expressed relative to preinjury isometric torque of bout 1, deficits in postinjury isometric torque during bout 2 (38%) did not differ from bout 1 (36%; P = 0.646) and were attenuated during bouts 3 through 6 (range, 24%-15%; P ≤ 0.014). Contents of dystrophin, β-sarcoglycan, and junctophilin did not change immediately after a single bout of 50 maximal ECCs (P ≥ 0.155); however, as a result of repeated bouts, contents of dystrophin, β-sarcoglycan, and junctophilin all increased compared with muscles that completed one or no bouts of ECC contractions (P ≤ 0.003). CONCLUSIONS The RBE represents a physiological measure of skeletal muscle plasticity. Here, we demonstrate that repeated bouts of ECC contractions increase contents of dystrophin, β-sarcoglycan, and junctophilin and attenuate postinjury torque deficits. Given our results, accumulation of membrane-associated proteins likely contributes to strength adaptations observed after repeated bouts of ECC contractions.
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Affiliation(s)
- Sylvia R. Sidky
- Division of Rehabilitation Science & Division of Physical Therapy, Department of Rehabilitation Medicine, University of Minnesota, Minneapolis, MN
| | | | - Dawn A. Lowe
- Division of Rehabilitation Science & Division of Physical Therapy, Department of Rehabilitation Medicine, University of Minnesota, Minneapolis, MN
| | - Cory W. Baumann
- Division of Rehabilitation Science & Division of Physical Therapy, Department of Rehabilitation Medicine, University of Minnesota, Minneapolis, MN
- Ohio Musculoskeletal and Neurological Institute (OMNI), Department of Biomedical Sciences, Ohio University, Athens, OH
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Abstract
The importance of defining sex differences across various biological and physiological mechanisms is more pervasive now than it has been over the past 15-20 years. As the muscle biology field pushes to identify small molecules and interventions to prevent, attenuate, or even reverse muscle wasting, we must consider the effect of sex as a biological variable. It should not be assumed that a therapeutic will affect males and females with equal efficacy or equivalent target affinities under conditions where muscle wasting is observed. With that said, it is not surprising to find that we have an unclear or even a poor understanding of the effects of sex or sex hormones on muscle wasting conditions. Although recent investigations are beginning to establish experimental approaches that will allow investigators to assess the impact of sex-specific hormones on muscle wasting, the field still needs rigorous scientific tools that will allow the community to address critical hypotheses centered around sex hormones. The focus of this review is on female sex hormones, specifically estrogens, and the roles that these hormones and their receptors play in skeletal muscle wasting conditions. With the overall review goal of assembling the current knowledge in the area of sexual dimorphism driven by estrogens with an effort to provide insights to interested physiologists on necessary considerations when trying to assess models for potential sex differences in cellular and molecular mechanisms of muscle wasting.
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Affiliation(s)
- Shawna L. McMillin
- 1Division of Rehabilitation Science, Department of Rehabilitation Medicine, Medical School, University of Minnesota, Minneapolis, Minnesota,2Division of Physical Therapy, Department of Rehabilitation Medicine, Medical School, University of Minnesota, Minneapolis, Minnesota
| | - Everett C. Minchew
- 3Department of Physiology, Brody School of Medicine, East Carolina Diabetes and Obesity Institute, East Carolina University, Greenville, North Carolina
| | - Dawn A. Lowe
- 1Division of Rehabilitation Science, Department of Rehabilitation Medicine, Medical School, University of Minnesota, Minneapolis, Minnesota,2Division of Physical Therapy, Department of Rehabilitation Medicine, Medical School, University of Minnesota, Minneapolis, Minnesota
| | - Espen E. Spangenburg
- 3Department of Physiology, Brody School of Medicine, East Carolina Diabetes and Obesity Institute, East Carolina University, Greenville, North Carolina
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Baumann CW, Lindsay A, Sidky SR, Ervasti JM, Warren GL, Lowe DA. Contraction-Induced Loss of Plasmalemmal Electrophysiological Function Is Dependent on the Dystrophin Glycoprotein Complex. Front Physiol 2021; 12:757121. [PMID: 34764884 PMCID: PMC8576390 DOI: 10.3389/fphys.2021.757121] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2021] [Accepted: 10/05/2021] [Indexed: 02/03/2023] Open
Abstract
Weakness and atrophy are key features of Duchenne muscular dystrophy (DMD). Dystrophin is one of the many proteins within the dystrophin glycoprotein complex (DGC) that maintains plasmalemmal integrity and cellular homeostasis. The dystrophin-deficient mdx mouse is also predisposed to weakness, particularly when subjected to eccentric (ECC) contractions due to electrophysiological dysfunction of the plasmalemma. Here, we determined if maintenance of plasmalemmal excitability during and after a bout of ECC contractions is dependent on intact and functional DGCs rather than, solely, dystrophin expression. Wild-type (WT) and dystrophic mice (mdx, mL172H and Sgcb-/- mimicking Duchenne, Becker and Limb-girdle Type 2E muscular dystrophies, respectively) with varying levels of dystrophin and DGC functionality performed 50 maximal ECC contractions with simultaneous torque and electromyographic measurements (M-wave root-mean-square, M-wave RMS). ECC contractions caused all mouse lines to lose torque (p<0.001); however, deficits were greater in dystrophic mouse lines compared to WT mice (p<0.001). Loss of ECC torque did not correspond to a reduction in M-wave RMS in WT mice (p=0.080), while deficits in M-wave RMS exceeded 50% in all dystrophic mouse lines (p≤0.007). Moreover, reductions in ECC torque and M-wave RMS were greater in mdx mice compared to mL172H mice (p≤0.042). No differences were observed between mdx and Sgcb-/- mice (p≥0.337). Regression analysis revealed ≥98% of the variance in ECC torque loss could be explained by the variance in M-wave RMS in dystrophic mouse lines (p<0.001) but not within WT mice (R 2=0.211; p=0.155). By comparing mouse lines that had varying amounts and functionality of dystrophin and other DGC proteins, we observed that (1) when all DGCs are intact, plasmalemmal action potential generation and conduction is maintained, (2) deficiency of the DGC protein β-sarcoglycan is as disruptive to plasmalemmal excitability as is dystrophin deficiency and, (3) some functionally intact DGCs are better than none. Our results highlight the significant role of the DGC plays in maintaining plasmalemmal excitability and that a collective synergism (via each DGC protein) is required for this complex to function properly during ECC contractions.
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Affiliation(s)
- Cory W. Baumann
- Department of Biomedical Sciences, Ohio Musculoskeletal and Neurological Institute (OMNI), Ohio University, Athens, OH, United States
- Divisions of Rehabilitation Science and Physical Therapy, Department of Rehabilitation Medicine, University of Minnesota, Minneapolis, MN, United States
| | - Angus Lindsay
- Divisions of Rehabilitation Science and Physical Therapy, Department of Rehabilitation Medicine, University of Minnesota, Minneapolis, MN, United States
- School of Exercise and Nutrition Sciences, Institute for Physical Activity and Nutrition, Deakin University, Geelong, VIC, Australia
| | - Sylvia R. Sidky
- Divisions of Rehabilitation Science and Physical Therapy, Department of Rehabilitation Medicine, University of Minnesota, Minneapolis, MN, United States
| | - James M. Ervasti
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN, United States
| | - Gordon L. Warren
- Department of Physical Therapy, Georgia State University, Atlanta, GA, United States
| | - Dawn A. Lowe
- Divisions of Rehabilitation Science and Physical Therapy, Department of Rehabilitation Medicine, University of Minnesota, Minneapolis, MN, United States
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16
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Arpke RW, Shams AS, Collins BC, Larson AA, Lu N, Lowe DA, Kyba M. Preservation of satellite cell number and regenerative potential with age reveals locomotory muscle bias. Skelet Muscle 2021; 11:22. [PMID: 34481522 PMCID: PMC8418011 DOI: 10.1186/s13395-021-00277-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2021] [Accepted: 08/24/2021] [Indexed: 12/03/2022] Open
Abstract
BACKGROUND Although muscle regenerative capacity declines with age, the extent to which this is due to satellite cell-intrinsic changes vs. environmental changes has been controversial. The majority of aging studies have investigated hindlimb locomotory muscles, principally the tibialis anterior, in caged sedentary mice, where those muscles are abnormally under-exercised. METHODS We analyze satellite cell numbers in 8 muscle groups representing locomotory and non-locomotory muscles in young and 2-year-old mice and perform transplantation assays of low numbers of hind limb satellite cells from young and old mice. RESULTS We find that satellite cell density does not decline significantly by 2 years of age in most muscles, and one muscle, the masseter, shows a modest but statistically significant increase in satellite cell density with age. The tibialis anterior and extensor digitorum longus were clear exceptions, showing significant declines. We quantify self-renewal using a transplantation assay. Dose dilution revealed significant non-linearity in self-renewal above a very low threshold, suggestive of competition between satellite cells for space within the pool. Assaying within the linear range, i.e., transplanting fewer than 1000 cells, revealed no evidence of decline in cell-autonomous self-renewal or regenerative potential of 2-year-old murine satellite cells. CONCLUSION These data demonstrate the value of comparative muscle analysis as opposed to overreliance on locomotory muscles, which are not used physiologically in aging sedentary mice, and suggest that self-renewal impairment with age is precipitously acquired at the geriatric stage, rather than being gradual over time, as previously thought.
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Affiliation(s)
- Robert W Arpke
- Lillehei Heart Institute and Department of Pediatrics, Medical School, University of Minnesota, Cancer and Cardiovascular Research Building, 2231 6th Street SE, Minneapolis, MN, 55455, USA
- Present address: Division of Biological Sciences, University of Missouri, 105 Tucker Hall, Columbia, MO, 65211, USA
| | - Ahmed S Shams
- Lillehei Heart Institute and Department of Pediatrics, Medical School, University of Minnesota, Cancer and Cardiovascular Research Building, 2231 6th Street SE, Minneapolis, MN, 55455, USA
- Human Anatomy and Embryology Department, Faculty of Medicine, Suez Canal University, Ismailia, Egypt
| | - Brittany C Collins
- Divisions of Rehabilitation Science and Physical Therapy, Department of Rehabilitation Medicine, Medical School, University of Minnesota, Minneapolis, MN, 55455, USA
- Present address: Department of Human Genetics, University of Utah, 15 North 2030 East, Salt Lake City, UT, 84112, USA
| | - Alexie A Larson
- Department of Integrative Biology and Physiology, Medical School, University of Minnesota, Minneapolis, MN, USA
| | - Nguyen Lu
- Lillehei Heart Institute and Department of Pediatrics, Medical School, University of Minnesota, Cancer and Cardiovascular Research Building, 2231 6th Street SE, Minneapolis, MN, 55455, USA
| | - Dawn A Lowe
- Department of Integrative Biology and Physiology, Medical School, University of Minnesota, Minneapolis, MN, USA
| | - Michael Kyba
- Lillehei Heart Institute and Department of Pediatrics, Medical School, University of Minnesota, Cancer and Cardiovascular Research Building, 2231 6th Street SE, Minneapolis, MN, 55455, USA.
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Baumann CW, Sidky SR, Lowe DA. Membrane Proteins Associated With The Repeated Bout Effect. Med Sci Sports Exerc 2021. [DOI: 10.1249/01.mss.0000760376.28898.65] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Trost JP, Chen M, Stark MM, Hodges JS, Richter S, Lindsay A, Warren GL, Lowe DA, Kimberley TJ. Voluntary and magnetically evoked muscle contraction protocol in males with Duchenne muscular dystrophy: Safety, feasibility, reliability, and validity. Muscle Nerve 2021; 64:190-198. [PMID: 33974714 DOI: 10.1002/mus.27323] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2020] [Revised: 05/04/2021] [Accepted: 05/08/2021] [Indexed: 01/21/2023]
Abstract
INTRODUCTION/AIMS Clinical trials addressing treatments for Duchenne muscular dystrophy (DMD) require reliable and valid measurement of muscle contractile function across all disease severity levels. In this work we aimed to evaluate a protocol combining voluntary and evoked contractions to measure strength and excitability of wrist extensor muscles for safety, feasibility, reliability, and discriminant validity between males with DMD and controls. METHODS Wrist extensor muscle strength and excitability were assessed in males with DMD (N = 10; mean ± standard deviation: 15.4 ± 5.9 years of age), using the Brooke Upper Extremity Rating Scale (scored 1-6), and age-matched healthy male controls (N = 15; 15.5 ± 5.0 years of age). Torque and electromyographic (EMG) measurements were analyzed under maximum voluntary and stimulated conditions at two visits. RESULTS A protocol of multiple maximal voluntary contractions (MVCs) and evoked twitch contractions was feasible and safe, with 96% of the participants completing the protocol and having a less than 7% strength decrement on either measure for both DMD patients and controls (P ≥ .074). Reliability was excellent for voluntary and evoked measurements of torque and EMG (intraclass correlation coefficient [ICC] over 0.90 and over 0.85 within and between visits, respectively). Torque, EMG, and timing of twitch-onset measurements discriminated between DMD and controls (P < .001). Twitch contraction time did not differ significantly between groups (P = .10). DISCUSSION Findings from this study show that the protocol is a safe, feasible, reliable, and a valid method to measure strength and excitability of wrist extensors in males with DMD.
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Affiliation(s)
- Joyceann P Trost
- Division of Rehabilitation Science, Department of Rehabilitation Medicine, University of Minnesota Medical School, Minneapolis, Minnesota, USA
| | - Mo Chen
- Department of Psychiatry, University of Minnesota Medical School, Minneapolis, Minnesota, USA
| | - Molly M Stark
- Department of Neurology, University of Minnesota Medical School, Minneapolis, Minnesota, USA
| | - James S Hodges
- Division of Biostatistics, School of Public Health, University of Minnesota, Minneapolis, Minnesota, USA
| | - Sara Richter
- Professional Data Analysts, Minneapolis, Minnesota, USA
| | - Angus Lindsay
- Institute for Physical Activity and Nutrition, School of Exercise and Nutrition Sciences, Deakin University, Geelong, Victoria, Australia
| | - Gordon L Warren
- Department of Physical Therapy, Georgia State University, Atlanta, Georgia, USA
| | - Dawn A Lowe
- Division of Rehabilitation Science, Department of Rehabilitation Medicine, University of Minnesota Medical School, Minneapolis, Minnesota, USA
| | - Teresa J Kimberley
- Division of Rehabilitation Science, Department of Rehabilitation Medicine, University of Minnesota Medical School, Minneapolis, Minnesota, USA.,School of Health and Rehabilitation Sciences, Department of Physical Therapy, MGH Institute of Health Professions, Boston, Massachusetts, USA
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Lindsay A, Holm J, Razzoli M, Bartolomucci A, Ervasti JM, Lowe DA. Some dystrophy phenotypes of dystrophin-deficient mdx mice are exacerbated by mild, repetitive daily stress. FASEB J 2021; 35:e21489. [PMID: 33734502 DOI: 10.1096/fj.202002500r] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2020] [Revised: 01/27/2021] [Accepted: 02/15/2021] [Indexed: 01/16/2023]
Abstract
Psychosocial stressors can cause physical inactivity, cardiac damage, and hypotension-induced death in the mdx mouse model of Duchenne muscular dystrophy (DMD). Because repeated exposure to mild stress can lead to habituation in wild-type mice, we investigated the response of mdx mice to a mild, daily stress to determine whether habituation occurred. Male mdx mice were exposed to a 30-sec scruff restraint daily for 12 weeks. Scruff restraint induced immediate physical inactivity that persisted for at least 60 minutes, and this inactivity response was just as robust after 12 weeks as it was after one day. Physical inactivity in the mdx mice was not associated with acute skeletal muscle contractile dysfunction. However, skeletal muscle of mdx mice that were repeatedly stressed had slow-twitch and tetanic relaxation times and trended toward high passive stiffness, possibly due to a small but significant increase in muscle fibrosis. Elevated urinary corticosterone secretion, adrenal hypertrophy, and a larger adrenal cortex indicating chronic activation of the hypothalamic-pituitary-adrenal (HPA) axis were measured in 12-week stressed mdx mice relative to those unstressed. However, pharmacological inhibition of the HPA axis did not affect scruff-induced physical inactivity and acute corticosterone injection did not recapitulate the scruff-induced phenotype, suggesting the HPA axis is not the driver of physical inactivity. Our results indicate that the response of mdx mice to an acute mild stress is non-habituating and that when that stressor is repeated daily for weeks, it is sufficient to exacerbate some phenotypes associated with dystrophinopathy in mdx mice.
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Affiliation(s)
- Angus Lindsay
- Department of Rehabilitation Medicine, University of Minnesota, Minneapolis, MN, USA
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN, USA
- Institute for Physical Activity and Nutrition, School of Exercise and Nutrition Sciences, Deakin University, Geelong, Australia
| | - John Holm
- Lillehei Heart Institute, University of Minnesota, Minneapolis, MN, USA
| | - Maria Razzoli
- Department of Integrative Biology and Physiology, University of Minnesota, Minneapolis, MN, USA
| | - Alessandro Bartolomucci
- Department of Integrative Biology and Physiology, University of Minnesota, Minneapolis, MN, USA
| | - James M Ervasti
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN, USA
| | - Dawn A Lowe
- Department of Rehabilitation Medicine, University of Minnesota, Minneapolis, MN, USA
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Lindsay A, Kemp B, Larson AA, Baumann CW, McCourt PM, Holm J, Karachunski P, Lowe DA, Ervasti JM. Tetrahydrobiopterin synthesis and metabolism is impaired in dystrophin-deficient mdx mice and humans. Acta Physiol (Oxf) 2021; 231:e13627. [PMID: 33580591 DOI: 10.1111/apha.13627] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2020] [Revised: 02/08/2021] [Accepted: 02/10/2021] [Indexed: 12/20/2022]
Abstract
AIM Loss of dystrophin causes oxidative stress and affects nitric oxide synthase-mediated vascular function in striated muscle. Because tetrahydrobiopterin is an antioxidant and co-factor for nitric oxide synthase, we tested the hypothesis that tetrahydrobiopterin would be low in mdx mice and humans deficient for dystrophin. METHODS Tetrahydrobiopterin and its metabolites were measured at rest and in response to exercise in Duchenne and Becker muscular dystrophy patients, age-matched male controls as well as wild-type, mdx and mdx mice transgenically overexpressing skeletal muscle-specific dystrophins. Mdx mice were also supplemented with tetrahydrobiopterin and pathophysiology was assessed. RESULTS Duchenne muscular dystrophy patients had lower urinary dihydrobiopterin + tetrahydrobiopterin/specific gravity1.020 compared to unaffected age-matched males and Becker muscular dystrophy patients. Mdx mice had low urinary and skeletal muscle dihydrobiopterin + tetrahydrobiopterin compared to wild-type mice. Overexpression of dystrophins that localize neuronal nitric oxide synthase restored dihydrobiopterin + tetrahydrobiopterin in mdx mice to wild-type levels while utrophin overexpression did not. Mdx mice and Duchenne muscular dystrophy patients did not increase tetrahydrobiopterin during exercise and in mdx mice tetrahydrobiopterin deficiency was likely because of lower levels of sepiapterin reductase in skeletal muscle. Tetrahydrobiopterin supplementation improved skeletal muscle strength, resistance to fatiguing and injurious contractions in vivo, increased utrophin and capillary density of skeletal muscle and lowered cardiac muscle fibrosis and left ventricular wall thickness in mdx mice. CONCLUSION These data demonstrate that impaired tetrahydrobiopterin synthesis is associated with dystrophin loss and treatment with tetrahydrobiopterin improves striated muscle histopathology and skeletal muscle function in mdx mice.
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Affiliation(s)
- Angus Lindsay
- Division of Rehabilitation Science and Division of Physical Therapy, Department of Rehabilitation Medicine, University of Minnesota, Minneapolis, MN, USA
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN, USA
- Institute for Physical Activity and Nutrition, School of Exercise and Nutrition Sciences, Deakin University, Geelong, Australia
| | - Bailey Kemp
- Lillehei Heart Institute, Cancer and Cardiovascular Research Center, University of Minnesota, Minneapolis, MN, USA
| | - Alexie A Larson
- Department of Integrative Biology and Physiology, University of Minnesota, Minneapolis, MN, USA
| | - Cory W Baumann
- Division of Rehabilitation Science and Division of Physical Therapy, Department of Rehabilitation Medicine, University of Minnesota, Minneapolis, MN, USA
| | - Preston M McCourt
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN, USA
| | - John Holm
- Lillehei Heart Institute, Cancer and Cardiovascular Research Center, University of Minnesota, Minneapolis, MN, USA
| | - Peter Karachunski
- Department of Pediatrics, University of Minnesota, Minneapolis, MN, USA
- Department of Neurology, University of Minnesota, Minneapolis, MN, USA
| | - Dawn A Lowe
- Division of Rehabilitation Science and Division of Physical Therapy, Department of Rehabilitation Medicine, University of Minnesota, Minneapolis, MN, USA
| | - James M Ervasti
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN, USA
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Vang P, Baumann CW, Barok R, Larson AA, Dougherty BJ, Lowe DA. Impact of estrogen deficiency on diaphragm and leg muscle contractile function in female mdx mice. PLoS One 2021; 16:e0249472. [PMID: 33788896 PMCID: PMC8011782 DOI: 10.1371/journal.pone.0249472] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2021] [Accepted: 03/18/2021] [Indexed: 12/28/2022] Open
Abstract
Female carriers of Duchenne muscular dystrophy (DMD) presenting with DMD symptomology similar to males with DMD, such as skeletal muscle weakness and cardiomyopathy, are termed manifesting carriers. There is phenotypic variability among manifesting carriers including the age of onset, which can range from the first to fourth decade of life. In females, estrogen levels typically begin to decline during the fourth decade of life and estrogen deficiency contributes to loss of muscle strength and recovery of strength following injury. Thus, we questioned whether the decline of estrogen impacts the development of DMD symptoms in females. To address this question, we studied 6-8 month-old homozygous mdx female mice randomly assigned to a sham or ovariectomy (OVX) surgical group. In vivo whole-body plethysmography assessed ventilatory function and diaphragm muscle strength was measured in vitro before and after fatigue. Anterior crural muscles were analyzed in vivo for contractile function, fatigue, and in response to eccentric contraction (ECC)-induced injury. For the latter, 50 maximal ECCs were performed by the anterior crural muscles to induce injury. Body mass, uterine mass, hypoxia-hypercapnia ventilatory response, and fatigue index were analyzed by a pooled unpaired t-test. A two-way ANOVA was used to analyze ventilatory measurements. Fatigue and ECC-injury recovery experiments were analyzed by a two-way repeated-measures ANOVA. Results show no differences between sham and OVX mdx mice in ventilatory function, strength, or recovery of strength after fatigue in the diaphragm muscle or anterior crural muscles (p ≥ 0.078). However, OVX mice had significantly greater eccentric torque loss and blunted recovery of strength after ECC-induced injury compared to sham mice (p ≤ 0.019). Although the results show that loss of estrogen has minimal impact on skeletal muscle contractile function in female mdx mice, a key finding suggests that estrogen is important in muscle recovery in female mdx mice after injury.
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Affiliation(s)
- Pangdra Vang
- Division of Rehabilitation Science, Department of Rehabilitation Medicine, University of Minnesota, Minneapolis, Minnesota, United States of America
| | - Cory W. Baumann
- Division of Rehabilitation Science, Department of Rehabilitation Medicine, University of Minnesota, Minneapolis, Minnesota, United States of America
| | - Rebecca Barok
- Division of Rehabilitation Science, Department of Rehabilitation Medicine, University of Minnesota, Minneapolis, Minnesota, United States of America
| | - Alexie A. Larson
- Department of Integrative Biology and Physiology, University of Minnesota, Minneapolis, Minnesota, United States of America
| | - Brendan J. Dougherty
- Division of Rehabilitation Science, Department of Rehabilitation Medicine, University of Minnesota, Minneapolis, Minnesota, United States of America
- Division of Physical Therapy, Department of Rehabilitation Medicine, University of Minnesota, Minneapolis, Minnesota, United States of America
| | - Dawn A. Lowe
- Division of Rehabilitation Science, Department of Rehabilitation Medicine, University of Minnesota, Minneapolis, Minnesota, United States of America
- Division of Physical Therapy, Department of Rehabilitation Medicine, University of Minnesota, Minneapolis, Minnesota, United States of America
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Cabelka CA, Baumann CW, Lindsay A, Norton A, Blixt NC, Le G, Warren GL, Mansky KC, Novotny SA, Lowe DA. Tissue selective effects of bazedoxifene on the musculoskeletal system in female mice. J Endocrinol 2021; 248:181-191. [PMID: 33295882 PMCID: PMC7933086 DOI: 10.1530/joe-20-0391] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/23/2020] [Accepted: 12/08/2020] [Indexed: 11/08/2022]
Abstract
The actions of selective estrogen receptor modulators are tissue dependent. The primary objective of the current study was to determine the tissue selective effects of bazedoxifene (BZA) on the musculoskeletal system of ovariectomized (OVX) female mice, focusing on the strengths of muscle-bone pairs in the lower hindlimb. Treatment with BZA after ovariectomy (OVX+BZA) did not prevent body or fat mass gains (P < 0.05). In vivo plantarflexor muscle isometric torque was not affected by treatment with BZA (P = 0.522). Soleus muscle peak isometric, concentric and eccentric tetanic force production were greater in OVX+BZA mice compared to OVX+E2 mice (P ≤ 0.048) with no effect on maximal isometric specific force (P = 0.228). Tibia from OVX+BZA mice had greater cortical cross-sectional area and moment of inertia than OVX mice treated with placebo (P < 0.001), but there was no impact of BZA treatment on cortical bone mineral density, cortical thickness, tibial bone ultimate load or stiffness (P ≥ 0.086). Overall, these results indicate that BZA may be an estrogen receptor agonist in skeletal muscle, as it has previously been shown in bone, providing minor benefits to the musculoskeletal system.
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Affiliation(s)
- Christine A. Cabelka
- Divisions of Rehabilitation Science and Physical Therapy, Department of Rehabilitation Medicine, Medical School, University of Minnesota; MMC 388, 420 Delaware St SE, Minneapolis, MN 55455, USA
- Department of Physical Therapy, The College of St. Scholastica; 940 Woodland Ave, Suite 210, Duluth, MN 55812, USA
| | - Cory W. Baumann
- Divisions of Rehabilitation Science and Physical Therapy, Department of Rehabilitation Medicine, Medical School, University of Minnesota; MMC 388, 420 Delaware St SE, Minneapolis, MN 55455, USA
| | - Angus Lindsay
- Divisions of Rehabilitation Science and Physical Therapy, Department of Rehabilitation Medicine, Medical School, University of Minnesota; MMC 388, 420 Delaware St SE, Minneapolis, MN 55455, USA
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota; 420 Washington Ave SE, Minneapolis, MN 55455, USA
| | - Andrew Norton
- Department of Developmental and Surgical Sciences, University of Minnesota; School of Dentistry, Room 16-146 Moos Tower, 515 Delaware St. SE, Minneapolis, MN 55455, USA
| | - Nick C. Blixt
- Department of Genetics, Cell Biology and Development, University of Minnesota; 6-160 Jackson Hall, 321 Church St.SE, Minneapolis, MN 55455, USA
| | - Gengyun Le
- Divisions of Rehabilitation Science and Physical Therapy, Department of Rehabilitation Medicine, Medical School, University of Minnesota; MMC 388, 420 Delaware St SE, Minneapolis, MN 55455, USA
| | - Gordon L. Warren
- Department of Physical Therapy, Georgia State University; P.O. Box 4019, Atlanta, GA 30302, USA
| | - Kim C. Mansky
- Department of Developmental and Surgical Sciences, University of Minnesota; School of Dentistry, Room 16-146 Moos Tower, 515 Delaware St. SE, Minneapolis, MN 55455, USA
| | - Susan A. Novotny
- Divisions of Rehabilitation Science and Physical Therapy, Department of Rehabilitation Medicine, Medical School, University of Minnesota; MMC 388, 420 Delaware St SE, Minneapolis, MN 55455, USA
- Gillette Children’s Specialty Healthcare, 200 University Avenue East, Saint Paul, MN 55101, USA
| | - Dawn A. Lowe
- Divisions of Rehabilitation Science and Physical Therapy, Department of Rehabilitation Medicine, Medical School, University of Minnesota; MMC 388, 420 Delaware St SE, Minneapolis, MN 55455, USA
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Ross JA, Tasfaout H, Levy Y, Morgan J, Cowling BS, Laporte J, Zanoteli E, Romero NB, Lowe DA, Jungbluth H, Lawlor MW, Mack DL, Ochala J. rAAV-related therapy fully rescues myonuclear and myofilament function in X-linked myotubular myopathy. Acta Neuropathol Commun 2020; 8:167. [PMID: 33076971 PMCID: PMC7574461 DOI: 10.1186/s40478-020-01048-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2020] [Accepted: 10/02/2020] [Indexed: 01/17/2023] Open
Abstract
X-linked myotubular myopathy (XLMTM) is a life-threatening skeletal muscle disease caused by mutations in the MTM1 gene. XLMTM fibres display a population of nuclei mispositioned in the centre. In the present study, we aimed to explore whether positioning and overall distribution of nuclei affects cellular organization and contractile function, thereby contributing to muscle weakness in this disease. We also assessed whether gene therapy alters nuclear arrangement and function. We used tissue from human patients and animal models, including XLMTM dogs that had received increasing doses of recombinant AAV8 vector restoring MTM1 expression (rAAV8-cMTM1). We then used single isolated muscle fibres to analyze nuclear organization and contractile function. In addition to the expected mislocalization of nuclei in the centre of muscle fibres, a novel form of nuclear mispositioning was observed: irregular spacing between those located at the fibre periphery, and an overall increased number of nuclei, leading to dramatically smaller and inconsistent myonuclear domains. Nuclear mislocalization was associated with decreases in global nuclear synthetic activity, contractile protein content and intrinsic myofilament force production. A contractile deficit originating at the myofilaments, rather than mechanical interference by centrally positioned nuclei, was supported by experiments in regenerated mouse muscle. Systemic administration of rAAV8-cMTM1 at doses higher than 2.5 × 1013 vg kg−1 allowed a full rescue of all these cellular defects in XLMTM dogs. Altogether, these findings identify previously unrecognized pathological mechanisms in human and animal XLMTM, associated with myonuclear defects and contractile filament function. These defects can be reversed by gene therapy restoring MTM1 expression in dogs with XLMTM.
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Nelson DM, Fasbender EK, Jakubiak MC, Lindsay A, Lowe DA, Ervasti JM. Rapid, redox-mediated mechanical susceptibility of the cortical microtubule lattice in skeletal muscle. Redox Biol 2020; 37:101730. [PMID: 33002761 PMCID: PMC7527753 DOI: 10.1016/j.redox.2020.101730] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2020] [Revised: 09/12/2020] [Accepted: 09/12/2020] [Indexed: 01/25/2023] Open
Abstract
The highly ordered cortical microtubule lattice of skeletal muscle is disorganized in dystrophin-deficient mdx mice. Implicated mechanisms include loss of dystrophin binding, altered α-tubulin posttranslational modification, expression of a β-tubulin involved in regeneration, and reactive oxygen species (ROS). Here we show that the transverse microtubules in mdx muscle expressing miniaturized dystrophins are rapidly lost after eccentric contraction. Analysis of mdx lines expressing different dystrophin constructs demonstrate that spectrin-like repeats R4-15 and R20-23 were required for mechanically stable microtubules. Microtubule loss was prevented by the non-specific antioxidant N-acetylcysteine while inhibition of NADPH oxidase 2 had only a partial effect, suggesting that ROS from multiple sources mediate the rapid loss of transverse microtubules after eccentric contraction. Finally, ablation of α-dystrobrevin, β- or γ-cytoplasmic actin phenocopied the transverse microtubule instability of miniaturized dystrophins. Our data demonstrate that multiple dystrophin domains, α-dystrobrevin and cytoplasmic actins are necessary for mechanically stable microtubules.
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Affiliation(s)
- D'anna M Nelson
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN, USA
| | - Elizabeth K Fasbender
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN, USA; College of Biological Sciences, University of Minnesota, Minneapolis, MN, USA
| | - Margurite C Jakubiak
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN, USA; College of Biological Sciences, University of Minnesota, Minneapolis, MN, USA
| | - Angus Lindsay
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN, USA; Department of Rehabilitation Medicine, University of Minnesota, Minneapolis, MN, USA
| | - Dawn A Lowe
- Department of Rehabilitation Medicine, University of Minnesota, Minneapolis, MN, USA
| | - James M Ervasti
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN, USA.
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Phung LA, Foster AD, Miller MS, Lowe DA, Thomas DD. Super-relaxed state of myosin in human skeletal muscle is fiber-type dependent. Am J Physiol Cell Physiol 2020; 319:C1158-C1162. [PMID: 32997515 DOI: 10.1152/ajpcell.00396.2020] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
The myosin super-relaxed state (SRX) in skeletal muscle is hypothesized to play an important role in regulating muscle contractility and thermogenesis in humans but has only been examined in model organisms. Here we report the first human skeletal muscle SRX measurements, using quantitative epifluorescence microscopy of fluorescent 2'/3'-O-(N-methylanthraniloyl) ATP (mantATP) single-nucleotide turnover. Myosin heavy chain (MHC) isoform expression was determined using gel electrophoresis for each permeabilized vastus lateralis fiber, to allow for novel comparisons of SRX between fiber types. We find that the fraction of myosin in SRX is less in MHC IIA fibers than in MHC I and IIAX fibers (P = 0.008). ATP turnover of SRX is faster in MHC IIAX fibers compared with MHC I and IIA fibers (P = 0.001). We conclude that SRX biochemistry is measurable in human skeletal muscle, and our data indicate that SRX depends on fiber type as classified by MHC isoform. Extension from this preliminary work would provide further understanding regarding the role of SRX in human muscle physiology.
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Affiliation(s)
- Lien A Phung
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, Minnesota
| | - Aurora D Foster
- Department of Kinesiology, University of Massachusetts, Amherst, Massachusetts
| | - Mark S Miller
- Department of Kinesiology, University of Massachusetts, Amherst, Massachusetts
| | - Dawn A Lowe
- Department of Rehabilitation Medicine, University of Minnesota, Minneapolis, Minnesota
| | - David D Thomas
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, Minnesota
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Larson AA, Baumann CW, Kyba M, Lowe DA. Oestradiol affects skeletal muscle mass, strength and satellite cells following repeated injuries. Exp Physiol 2020; 105:1700-1707. [PMID: 32851730 DOI: 10.1113/ep088827] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Accepted: 08/24/2020] [Indexed: 02/06/2023]
Abstract
NEW FINDINGS What is the central question of this study? Oestradiol (E2 ) plays an important role in regulating skeletal muscle strength in females. To what extent does E2 deficiency affect recovery of strength and satellite cell number when muscle is challenged by multiple injuries? What is the main finding and its importance? E2 deficiency impairs the adaptive potential of skeletal muscle following repeated injuries, as measured by muscle mass and strength. The impairment is likely multifactorial with our data indicating that one mechanism is reduction in satellite cell number. Our findings have implications for ageing, hormone replacement and regenerative medicine in regards to maintaining satellite cell number and ultimately the preservation of skeletal muscle's adaptive potential. ABSTRACT Oestradiol's effects on skeletal muscle are multifactorial including the preservation of mass, contractility and regeneration. Here, we aimed to determine the extent to which oestradiol deficiency affects strength recovery when muscle is challenged by multiple BaCl2 -induced injuries and to assess how satellite cell number is influenced by the combination of oestradiol deficiency and repetitive skeletal muscle injuries. A longitudinal study was designed, using an in vivo anaesthetized mouse approach to precisely and repeatedly measure maximal isometric torque, coupled with endpoint fluorescence-activated cell sorting to quantify satellite cells. Isometric torque and strength gains were lower in ovariectomized mice at several time points after the injuries compared to those treated with 17β-oestradiol. Satellite cell number was 41-43% lower in placebo- than in oestradiol-treated ovariectomized mice, regardless of injury status or number of injuries. Together, these results indicate that the loss of oestradiol blunts adaptive strength gains and that the number of satellite cells likely contributes to the impairment.
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Affiliation(s)
- Alexie A Larson
- Department of Integrative Biology and Physiology, Medical School, University of Minnesota, Minneapolis, MN, USA
| | - Cory W Baumann
- Divisions of Rehabilitation Science and Physical Therapy, Department of Rehabilitation Medicine, Medical School, University of Minnesota, Minneapolis, MN, USA
| | - Michael Kyba
- Lillehei Heart Institute and Department of Pediatrics, Medical School, University of Minnesota, Minneapolis, MN, USA
| | - Dawn A Lowe
- Divisions of Rehabilitation Science and Physical Therapy, Department of Rehabilitation Medicine, Medical School, University of Minnesota, Minneapolis, MN, USA
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Abstract
PURPOSE Muscle that lacks dystrophin, as in the mdx mouse, has a heightened sensitivity to eccentric (ECC) contraction-induced strength loss but an enhanced rate of recovery. However, the timeline and mechanisms underlying why mdx muscle recovers quicker have yet to be determined. We used an EMG approach to analyze plasmalemma electrophysiological function during and after ECC contraction-induced injury to test the hypothesis that loss of plasmalemmal excitability is a transient event in mdx muscle. METHODS Mice were implanted with stimulating electrodes on the common peroneal nerve and EMG electrodes on the tibialis anterior muscle. Anterior crural muscles of anesthetized mice performed one or two bouts of 50 injurious ECC contractions, and recovery of maximal isometric torque and M-wave root mean square (RMS) were assessed after each bout. RESULTS Maximal isometric torque and M-wave RMS were equally reduced 62% (P < 0.001) in mdx mice immediately after the initial ECC injury. For these mdx mice, M-wave RMS was still reduced at 2 d postinjury (P = 0.034) but was not different from preinjury values by 6 d (P = 0.106), whereas torque took up to 9 d to recover (P = 0.333). M-wave RMS did not change (P = 0.390) in wild-type mice in response to ECC injury, whereas torque decreased 35% (P < 0.001) and recovered by day 2 (P = 0.311). Results from the second bout of ECC contractions were similar to those observed during and after the initial injury. CONCLUSION Functional dystrophin is necessary for excitation to occur at the plasmalemma during ECC contractions but is not essential for the complete recovery of plasmalemma electrophysiological function or maximal isometric strength.
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Affiliation(s)
- Cory W Baumann
- Divisions of Rehabilitation Science and Physical Therapy, Department of Rehabilitation Medicine, Medical School, University of Minnesota, Minneapolis, MN
| | - Gordon L Warren
- Department of Physical Therapy, Georgia State University, Atlanta, GA
| | - Dawn A Lowe
- Divisions of Rehabilitation Science and Physical Therapy, Department of Rehabilitation Medicine, Medical School, University of Minnesota, Minneapolis, MN
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LE GENGYUNC, Lowe DA. Activation Of Specific Estrogen Receptor Isotype Mediates Skeletal Muscle Force Potentiation In Ovariectomized Mice. Med Sci Sports Exerc 2020. [DOI: 10.1249/01.mss.0000685488.86500.6b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Baumann CW, Lowe DA. Aging Blunts The Repeated Bout Effect In Skeletal Muscle. Med Sci Sports Exerc 2020. [DOI: 10.1249/01.mss.0000670156.93752.a3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Bosnakovski D, Shams AS, Yuan C, da Silva MT, Ener ET, Baumann CW, Lindsay AJ, Verma M, Asakura A, Lowe DA, Kyba M. Transcriptional and cytopathological hallmarks of FSHD in chronic DUX4-expressing mice. J Clin Invest 2020; 130:2465-2477. [PMID: 32250341 PMCID: PMC7190912 DOI: 10.1172/jci133303] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2019] [Accepted: 01/23/2020] [Indexed: 12/11/2022] Open
Abstract
Facioscapulohumeral muscular dystrophy (FSHD) is caused by loss of repression of the DUX4 gene; however, the DUX4 protein is rare and difficult to detect in human muscle biopsies, and pathological mechanisms are obscure. FSHD is also a chronic disease that progresses slowly over decades. We used the sporadic, low-level, muscle-specific expression of DUX4 enabled by the iDUX4pA-HSA mouse to develop a chronic long-term muscle disease model. After 6 months of extremely low sporadic DUX4 expression, dystrophic muscle presented hallmarks of FSHD histopathology, including muscle degeneration, capillary loss, fibrosis, and atrophy. We investigated the transcriptional profile of whole muscle as well as endothelial cells and fibroadiopogenic progenitors (FAPs). Strikingly, differential gene expression profiles of both whole muscle and, to a lesser extent, FAPs, showed significant overlap with transcriptional profiles of MRI-guided human FSHD muscle biopsies. These results demonstrate a pathophysiological similarity between disease in muscles of iDUX4pA-HSA mice and humans with FSHD, solidifying the value of chronic rare DUX4 expression in mice for modeling pathological mechanisms in FSHD and highlighting the importance FAPs in this disease.
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Affiliation(s)
- Darko Bosnakovski
- Lillehei Heart Institute and
- Department of Pediatrics, Medical School, University of Minnesota, Minneapolis, Minnesota, USA
- Faculty of Medical Sciences, University Goce Delcev, Stip, North Macedonia
| | - Ahmed S. Shams
- Lillehei Heart Institute and
- Department of Pediatrics, Medical School, University of Minnesota, Minneapolis, Minnesota, USA
- Human Anatomy and Embryology Department, Faculty of Medicine, Suez Canal University, Ismailia, Egypt
| | - Ce Yuan
- Bioinformatics and Computational Biology Program
| | - Meiricris T. da Silva
- Lillehei Heart Institute and
- Department of Pediatrics, Medical School, University of Minnesota, Minneapolis, Minnesota, USA
| | - Elizabeth T. Ener
- Lillehei Heart Institute and
- Department of Pediatrics, Medical School, University of Minnesota, Minneapolis, Minnesota, USA
| | | | | | - Mayank Verma
- Department of Neurology, Medical School, University of Minnesota, Minneapolis, Minnesota, USA
| | - Atsushi Asakura
- Department of Neurology, Medical School, University of Minnesota, Minneapolis, Minnesota, USA
| | | | - Michael Kyba
- Lillehei Heart Institute and
- Department of Pediatrics, Medical School, University of Minnesota, Minneapolis, Minnesota, USA
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Iñigo MR, Amorese AJ, Tarpey MD, Balestrieri NP, Jones KG, Patteson DJ, Jackson KC, Torres MJ, Lin CT, Smith CD, Heden TD, McMillin SL, Weyrauch LA, Stanley EC, Schmidt CA, Kilburg-Basnyat BB, Reece SW, Psaltis CE, Leinwand LA, Funai K, McClung JM, Gowdy KM, Witczak CA, Lowe DA, Neufer PD, Spangenburg EE. Estrogen receptor-α in female skeletal muscle is not required for regulation of muscle insulin sensitivity and mitochondrial regulation. Mol Metab 2020; 34:1-15. [PMID: 32180550 PMCID: PMC6994285 DOI: 10.1016/j.molmet.2019.12.010] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/14/2019] [Revised: 12/16/2019] [Accepted: 12/17/2019] [Indexed: 12/18/2022] Open
Abstract
OBJECTIVE Estrogen receptor-α (ERα) is a nuclear receptor family member thought to substantially contribute to the metabolic regulation of skeletal muscle. However, previous mouse models utilized to assess the necessity of ERα signaling in skeletal muscle were confounded by altered developmental programming and/or influenced by secondary effects, making it difficult to assign a causal role for ERα. The objective of this study was to determine the role of skeletal muscle ERα in regulating metabolism in the absence of confounding factors of development. METHODS A novel mouse model was developed allowing for induced deletion of ERα in adult female skeletal muscle (ERαKOism). ERαshRNA was also used to knockdown ERα (ERαKD) in human myotubes cultured from primary human skeletal muscle cells isolated from muscle biopsies from healthy and obese insulin-resistant women. RESULTS Twelve weeks of HFD exposure had no differential effects on body composition, VO2, VCO2, RER, energy expenditure, and activity counts across genotypes. Although ERαKOism mice exhibited greater glucose intolerance than wild-type (WT) mice after chronic HFD, ex vivo skeletal muscle glucose uptake was not impaired in the ERαKOism mice. Expression of pro-inflammatory genes was altered in the skeletal muscle of the ERαKOism, but the concentrations of these inflammatory markers in the systemic circulation were either lower or remained similar to the WT mice. Finally, skeletal muscle mitochondrial respiratory capacity, oxidative phosphorylation efficiency, and H2O2 emission potential was not affected in the ERαKOism mice. ERαKD in human skeletal muscle cells neither altered differentiation capacity nor caused severe deficits in mitochondrial respiratory capacity. CONCLUSIONS Collectively, these results suggest that ERα function is superfluous in protecting against HFD-induced skeletal muscle metabolic derangements after postnatal development is complete.
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Affiliation(s)
- Melissa R Iñigo
- East Carolina University Brody School of Medicine, Department of Physiology, Greenville, NC, USA
| | - Adam J Amorese
- East Carolina University Brody School of Medicine, Department of Physiology, Greenville, NC, USA
| | - Michael D Tarpey
- East Carolina University Brody School of Medicine, Department of Physiology, Greenville, NC, USA
| | - Nicholas P Balestrieri
- East Carolina University, East Carolina Diabetes and Obesity Institute, Greenville, NC, USA
| | - Keith G Jones
- East Carolina University, East Carolina Diabetes and Obesity Institute, Greenville, NC, USA
| | - Daniel J Patteson
- East Carolina University, East Carolina Diabetes and Obesity Institute, Greenville, NC, USA
| | - Kathryn C Jackson
- University of Maryland, School of Public Health, Department of Kinesiology, College Park, MD, USA
| | - Maria J Torres
- East Carolina University, Department of Kinesiology, Greenville, NC, USA
| | - Chien-Te Lin
- East Carolina University, East Carolina Diabetes and Obesity Institute, Greenville, NC, USA
| | - Cody D Smith
- East Carolina University Brody School of Medicine, Department of Physiology, Greenville, NC, USA
| | - Timothy D Heden
- East Carolina University, Department of Kinesiology, Greenville, NC, USA
| | - Shawna L McMillin
- East Carolina University, Department of Kinesiology, Greenville, NC, USA
| | - Luke A Weyrauch
- East Carolina University, Department of Kinesiology, Greenville, NC, USA
| | - Erin C Stanley
- East Carolina University, Department of Kinesiology, Greenville, NC, USA
| | - Cameron A Schmidt
- East Carolina University Brody School of Medicine, Department of Physiology, Greenville, NC, USA
| | - Brita B Kilburg-Basnyat
- East Carolina University Brody School of Medicine, Department of Pharmacology and Toxicology, Greenville, NC, USA
| | - Sky W Reece
- East Carolina University Brody School of Medicine, Department of Pharmacology and Toxicology, Greenville, NC, USA
| | - Christine E Psaltis
- East Carolina University Brody School of Medicine, Department of Pharmacology and Toxicology, Greenville, NC, USA
| | - Leslie A Leinwand
- University of Colorado, Department of Molecular, Cellular, and Developmental Biology and BioFrontiers Institute, Boulder, CO, USA
| | - Katsuhiko Funai
- East Carolina University Brody School of Medicine, Department of Physiology, Greenville, NC, USA; East Carolina University, East Carolina Diabetes and Obesity Institute, Greenville, NC, USA; East Carolina University, Department of Kinesiology, Greenville, NC, USA
| | - Joseph M McClung
- East Carolina University Brody School of Medicine, Department of Physiology, Greenville, NC, USA; East Carolina University, East Carolina Diabetes and Obesity Institute, Greenville, NC, USA
| | - Kymberly M Gowdy
- East Carolina University, East Carolina Diabetes and Obesity Institute, Greenville, NC, USA; East Carolina University Brody School of Medicine, Department of Pharmacology and Toxicology, Greenville, NC, USA
| | - Carol A Witczak
- East Carolina University Brody School of Medicine, Department of Physiology, Greenville, NC, USA; East Carolina University, East Carolina Diabetes and Obesity Institute, Greenville, NC, USA; East Carolina University, Department of Kinesiology, Greenville, NC, USA; East Carolina University, Department of Biochemistry and Molecular Biology, Greenville, NC, USA
| | - Dawn A Lowe
- University of Minnesota, Department of Rehabilitation Medicine, Division of Rehabilitation Science and Division of Physical Therapy, Minneapolis, MN, USA
| | - P Darrell Neufer
- East Carolina University Brody School of Medicine, Department of Physiology, Greenville, NC, USA; East Carolina University, East Carolina Diabetes and Obesity Institute, Greenville, NC, USA; East Carolina University, Department of Kinesiology, Greenville, NC, USA
| | - Espen E Spangenburg
- East Carolina University Brody School of Medicine, Department of Physiology, Greenville, NC, USA; East Carolina University, East Carolina Diabetes and Obesity Institute, Greenville, NC, USA; East Carolina University, Department of Kinesiology, Greenville, NC, USA.
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Lowe DA, Kararigas G. Editorial: New Insights into Estrogen/Estrogen Receptor Effects in the Cardiac and Skeletal Muscle. Front Endocrinol (Lausanne) 2020; 11:141. [PMID: 32265837 PMCID: PMC7096469 DOI: 10.3389/fendo.2020.00141] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/26/2020] [Accepted: 03/02/2020] [Indexed: 11/13/2022] Open
Affiliation(s)
- Dawn A. Lowe
- Department of Rehabilitation Medicine, University of Minnesota, Minneapolis, MN, United States
| | - Georgios Kararigas
- Charité – Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
- DZHK (German Centre for Cardiovascular Research), Partner Site Berlin, Berlin, Germany
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Lindsay A, Chamberlain CM, Witthuhn BA, Lowe DA, Ervasti JM. Dystrophinopathy-associated dysfunction of Krebs cycle metabolism. Hum Mol Genet 2020; 28:942-951. [PMID: 30476171 DOI: 10.1093/hmg/ddy404] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2018] [Revised: 10/23/2018] [Accepted: 11/13/2018] [Indexed: 01/03/2023] Open
Abstract
Duchenne muscular dystrophy is a deadly muscle-wasting disorder caused by loss of dystrophin protein. Studies suggest that metabolic alterations are important to disease pathogenesis. Because muscle accounts for ~40% of body mass, we hypothesized that dystrophy-mediated metabolic changes would be measurable in biofluids and that a metabolomic analysis of urine would provide insight into the metabolic status of dystrophic muscle. Using the mdx mouse model, we performed a large-scale metabolomic screen at 1 and 3 months. While 10% of metabolites were altered at age 1 month, 40% were changed at 3 months. Principal component analysis distinguished wild-type from mdx animals, with the greatest separation at 3 months. A critical distinguishing pathway was Krebs cycle metabolite depletion in mdx urine. Five of seven detected Krebs cycle metabolites were depleted in mdx urine, with succinate being the most robustly affected metabolite. Using selected reaction monitoring mass spectrometry, we demonstrated that muscle-specific dystrophin expression corrects mdx succinate depletion. When subjected to downhill treadmill running, wild-type and mdx mice expressing recombinant dystrophin in skeletal muscle displayed significant increases in urinary succinate levels. However, mdx succinate levels were unchanged, suggesting urinary succinate depletion may reflect an inability to upregulate the Krebs cycle following exercise. Finally, we show that supplementing the Krebs cycle in an ex vivo fatigue/recovery assay significantly impacts mdx muscle performance but has no effect on wild-type muscle. Our results suggest that global metabolic impairment is associated with mdx disease progression and that Krebs cycle deficiencies are a downstream consequence of dystrophin loss.
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Affiliation(s)
- Angus Lindsay
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN, USA.,Division of Rehabilitation Science and Division of Physical Therapy, Department of Rehabilitation Medicine, University of Minnesota, Minneapolis, MN, USA
| | - Christopher M Chamberlain
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN, USA
| | - Bruce A Witthuhn
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN, USA
| | - Dawn A Lowe
- Division of Rehabilitation Science and Division of Physical Therapy, Department of Rehabilitation Medicine, University of Minnesota, Minneapolis, MN, USA
| | - James M Ervasti
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN, USA
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Phung LA, Foster AD, Miller MS, Lowe DA, Thomas DD. Detection of Super-Relaxed Myosin in Specific Human Skeletal Muscle Fiber Types. Biophys J 2020. [DOI: 10.1016/j.bpj.2019.11.1587] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
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Lindsay A, Baumann CW, Rebbeck RT, Yuen SL, Southern WM, Hodges JS, Cornea RL, Thomas DD, Ervasti JM, Lowe DA. Mechanical factors tune the sensitivity of mdx muscle to eccentric strength loss and its protection by antioxidant and calcium modulators. Skelet Muscle 2020; 10:3. [PMID: 32007101 PMCID: PMC6995146 DOI: 10.1186/s13395-020-0221-2] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2019] [Accepted: 01/09/2020] [Indexed: 12/17/2022] Open
Abstract
Background Dystrophin deficiency sensitizes skeletal muscle of mice to eccentric contraction (ECC)-induced strength loss. ECC protocols distinguish dystrophin-deficient from healthy, wild type muscle, and test the efficacy of therapeutics for Duchenne muscular dystrophy (DMD). However, given the large lab-to-lab variability in ECC-induced strength loss of dystrophin-deficient mouse skeletal muscle (10–95%), mechanical factors of the contraction likely impact the degree of loss. Therefore, the purpose of this study was to evaluate the extent to which mechanical variables impact sensitivity of dystrophin-deficient mouse skeletal muscle to ECC. Methods We completed ex vivo and in vivo muscle preparations of the dystrophin-deficient mdx mouse and designed ECC protocols within physiological ranges of contractile parameters (length change, velocity, contraction duration, and stimulation frequencies). To determine whether these contractile parameters affected known factors associated with ECC-induced strength loss, we measured sarcolemmal damage after ECC as well as strength loss in the presence of the antioxidant N-acetylcysteine (NAC) and small molecule calcium modulators that increase SERCA activity (DS-11966966 and CDN1163) or lower calcium leak from the ryanodine receptor (Chloroxine and Myricetin). Results The magnitude of length change, work, and stimulation duration ex vivo and in vivo of an ECC were the most important determinants of strength loss in mdx muscle. Passive lengthening and submaximal stimulations did not induce strength loss. We further showed that sarcolemmal permeability was associated with muscle length change, but it only accounted for a minimal fraction (21%) of the total strength loss (70%). The magnitude of length change also significantly influenced the degree to which NAC and small molecule calcium modulators protected against ECC-induced strength loss. Conclusions These results indicate that ECC-induced strength loss of mdx skeletal muscle is dependent on the mechanical properties of the contraction and that mdx muscle is insensitive to ECC at submaximal stimulation frequencies. Rigorous design of ECC protocols is critical for effective use of strength loss as a readout in evaluating potential therapeutics for muscular dystrophy.
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Affiliation(s)
- Angus Lindsay
- Division of Rehabilitation Science and Division of Physical Therapy, Department of Rehabilitation Medicine, University of Minnesota, MMC 388, 420 Delaware Street SE, Minneapolis, 55455, USA.,Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, 6-155 Jackson Hall, 321 Church Street SE, Minneapolis, 55455, USA.,Institute for Physical Activity and Nutrition (IPAN), School of Exercise and Nutrition Sciences, Deakin University, Geelong, VIC, 3220, Australia
| | - Cory W Baumann
- Division of Rehabilitation Science and Division of Physical Therapy, Department of Rehabilitation Medicine, University of Minnesota, MMC 388, 420 Delaware Street SE, Minneapolis, 55455, USA
| | - Robyn T Rebbeck
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, 6-155 Jackson Hall, 321 Church Street SE, Minneapolis, 55455, USA
| | - Samantha L Yuen
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, 6-155 Jackson Hall, 321 Church Street SE, Minneapolis, 55455, USA
| | - William M Southern
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, 6-155 Jackson Hall, 321 Church Street SE, Minneapolis, 55455, USA
| | - James S Hodges
- Division of Biostatistics, University of Minnesota, A460 Mayo Building, 420 Delaware Street SE, Minneapolis, 55455, USA
| | - Razvan L Cornea
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, 6-155 Jackson Hall, 321 Church Street SE, Minneapolis, 55455, USA
| | - David D Thomas
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, 6-155 Jackson Hall, 321 Church Street SE, Minneapolis, 55455, USA
| | - James M Ervasti
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, 6-155 Jackson Hall, 321 Church Street SE, Minneapolis, 55455, USA
| | - Dawn A Lowe
- Division of Rehabilitation Science and Division of Physical Therapy, Department of Rehabilitation Medicine, University of Minnesota, MMC 388, 420 Delaware Street SE, Minneapolis, 55455, USA.
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Baumann CW, Warren GL, Lowe DA. Sites of Disruption in Dystrophic Muscle Following Eccentric Contractions. Med Sci Sports Exerc 2019. [DOI: 10.1249/01.mss.0000560935.20338.96] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Collins BC, Laakkonen EK, Lowe DA. Aging of the musculoskeletal system: How the loss of estrogen impacts muscle strength. Bone 2019; 123:137-144. [PMID: 30930293 PMCID: PMC6491229 DOI: 10.1016/j.bone.2019.03.033] [Citation(s) in RCA: 84] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/06/2019] [Revised: 03/21/2019] [Accepted: 03/26/2019] [Indexed: 02/06/2023]
Abstract
Skeletal muscle weakness occurs with aging and in females this is compounded by the loss of estrogen with ovarian failure. Estrogen deficiency mediates decrements in muscle strength from both inadequate preservation of skeletal muscle mass and decrements in the quality of the remaining skeletal muscle. Processes and components of skeletal muscle that are affected by estrogens are beginning to be identified. This review focuses on mechanisms that contribute to the loss of muscle force generation when estrogen is low in females, and conversely the maintenance of strength by estrogen. Evidence is accumulating that estrogen deficiency induces apoptosis in skeletal muscle contributing to loss of mass and thus strength. Estrogen sensitive processes that affect quality, i.e., force generating capacity of muscle, include myosin phosphorylation and satellite cell function. Further detailing these mechanisms and identifying additional mechanisms that underlie estrogenic effects on skeletal muscle is important foundation for the design of therapeutic strategies to minimize skeletal muscle pathologies, such as sarcopenia and dynapenia.
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Affiliation(s)
- Brittany C Collins
- Department of Human Genetics, Medical School, University of Utah, United States of America
| | - Eija K Laakkonen
- Gerontology Research Center and Faculty of Sport and Health Sciences, University of Jyväskylä, Finland
| | - Dawn A Lowe
- Divisions of Rehabilitation Science and Physical Therapy, Department of Rehabilitation Medicine, Medical School, University of Minnesota, United States of America.
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Lindsay A, Southern WM, McCourt PM, Larson AA, Hodges JS, Lowe DA, Ervasti JM. Variable cytoplasmic actin expression impacts the sensitivity of different dystrophin-deficient mdx skeletal muscles to eccentric contraction. FEBS J 2019; 286:2562-2576. [PMID: 30942954 DOI: 10.1111/febs.14831] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2018] [Revised: 01/24/2019] [Accepted: 04/01/2019] [Indexed: 11/29/2022]
Abstract
Eccentric contractions (ECCs) induce force loss in several skeletal muscles of dystrophin-deficient mice (mdx), with the exception of the soleus (Sol). The eccentric force : isometric force (ECC : ISO), expression level of utrophin, fiber type distribution, and sarcoendoplasmic reticulum calcium ATPase expression are factors that differ between muscles and may contribute to the sensitivity of mdx skeletal muscle to ECC. Here, we confirm that the Sol of mdx mice loses only 13% force compared to 87% in the extensor digitorum longus (EDL) following 10 ECC of isolated muscles. The Sol has a greater proportion of fibers expressing Type I myosin heavy chain (MHC) and expresses 2.3-fold more utrophin compared to the EDL. To examine the effect of ECC : ISO, we show that the mdx Sol is insensitive to ECC at ECC : ISO up to 230 ± 15%. We show that the peroneus longus (PL) muscle presents with similar ECC : ISO compared to the EDL, intermediate force loss (68%) following 10 ECC, and intermediate fiber type distribution and utrophin expression relative to EDL and Sol. The combined absence of utrophin and dystrophin in mdx/utrophin-/- mice rendered the Sol only partially susceptible to ECC and exacerbated force loss in the EDL and PL. Most interestingly, the expression levels of cytoplasmic β- and γ-actins correlate inversely with a given muscle's sensitivity to ECC; EDL < PL < Sol. Our data indicate that fiber type, utrophin, and cytoplasmic actin expression all contribute to the differential sensitivities of mdxEDL, PL, and Sol muscles to ECC.
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Affiliation(s)
- Angus Lindsay
- Division of Rehabilitation Science and Division of Physical Therapy, Department of Rehabilitation Medicine, University of Minnesota, Minneapolis, MN, USA.,Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN, USA
| | - William M Southern
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN, USA
| | - Preston M McCourt
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN, USA
| | - Alexie A Larson
- Department of Integrative Biology and Physiology, University of Minnesota, Minneapolis, MN, USA
| | - James S Hodges
- Division of Biostatistics, University of Minnesota, Minneapolis, MN, USA
| | - Dawn A Lowe
- Division of Rehabilitation Science and Division of Physical Therapy, Department of Rehabilitation Medicine, University of Minnesota, Minneapolis, MN, USA
| | - James M Ervasti
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN, USA
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Lindsay A, Schmiechen A, Chamberlain CM, Ervasti JM, Lowe DA. Neopterin/7,8-dihydroneopterin is elevated in Duchenne muscular dystrophy patients and protects mdx skeletal muscle function. Exp Physiol 2019; 103:995-1009. [PMID: 29791760 DOI: 10.1113/ep087031] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2018] [Accepted: 04/30/2018] [Indexed: 01/04/2023]
Abstract
NEW FINDINGS What is the central question of this study? We examined whether the macrophage-synthesized antioxidant 7,8-dihydroneopterin was elevated in Duchenne muscular dystrophy (DMD) patients. We then examined whether 7,8-dihydroneopterin could protect dystrophic skeletal mouse muscle from eccentric contraction-induced force loss and improve recovery. What is the main finding and its importance? Urinary neopterin/creatinine and 7,8-dihydroneopterin/creatinine were elevated in DMD patients. 7,8-Dihydroneopterin attenuated eccentric contraction-induced force loss of dystrophic skeletal mouse muscle and accelerated recovery of force. These results suggest that eccentric contraction-induced force loss is mediated, in part, by an oxidative component and provides a potential protective role for 7,8-dihydroneopterin in DMD. ABSTRACT Macrophage infiltration is a hallmark of dystrophin-deficient muscle. We tested the hypothesis that Duchenne muscular dystrophy (DMD) patients would have elevated levels of the macrophage-synthesized pterins, neopterin and 7,8-dihydroneopterin, compared with unaffected age-matched control subjects. Urinary neopterin/creatinine and 7,8-dihydroneopterin/creatinine were elevated in DMD patients, and 7,8-dihydroneopterin/creatinine was associated with patient age and ambulation. Urinary 7,8-dihydroneopterin corrected for specific gravity was also elevated in DMD patients. Given that 7,8-dihydroneopterin is an antioxidant, we then identified a potential role for 7,8-dihydroneopterin in disease pathology. We assessed whether 7,8-dihydroneopterin could: (i) protect against isometric force loss in wild-type skeletal muscle exposed to various pro-oxidants; and (ii) protect wild-type and mdx muscle from eccentric contraction-induced force loss, which has an oxidative component. Force loss was elicited in isolated extensor digitorum longus (EDL) muscles by 10 eccentric contractions, and recovery of force after the contractions was measured in the presence of exogenous 7,8-dihydroneopterin. 7,8-Dihydroneopterin attenuated isometric force loss by wild-type EDL muscles when challenged by H2 O2 and HOCl, but exacerbated force loss when challenged by SIN-1 (NO• , O2• , ONOO- ). 7,8-Dihydroneopterin attenuated eccentric contraction-induced force loss in mdx muscle. Isometric force production by EDL muscles of mdx mice also recovered to a greater degree after eccentric contractions in the presence of 7,8-dihydroneopterin. The results corroborate macrophage activation in DMD patients, provide a potential protective role for 7,8-dihydroneopterin in the susceptibility of dystrophic muscle to eccentric contractions and indicate that oxidative stress contributes to eccentric contraction-induced force loss in mdx skeletal muscle.
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Affiliation(s)
- Angus Lindsay
- Division of Rehabilitation Science and Division of Physical Therapy, Department of Rehabilitation Medicine, University of Minnesota, Minneapolis, MN, USA.,Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN, USA
| | - Alexandra Schmiechen
- Lillehei Heart Institute, Cancer and Cardiovascular Research Center, University of Minnesota, Minneapolis, MN, USA
| | - Christopher M Chamberlain
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN, USA
| | - James M Ervasti
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN, USA
| | - Dawn A Lowe
- Division of Rehabilitation Science and Division of Physical Therapy, Department of Rehabilitation Medicine, University of Minnesota, Minneapolis, MN, USA
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LE GENGYUN, Baumann CW, Warren GL, Lowe DA. Increased Fiber Excitability Does Not Contribute to Post‐Tetanic Potentiation in Mice. FASEB J 2019. [DOI: 10.1096/fasebj.2019.33.1_supplement.701.14] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- GENGYUN LE
- Rehabilitation MedicineUniversity of MinnesotaMinneapolisMN
- Natural ScienceMetropolitan State UniversitySt. PaulMN
| | - Cory W Baumann
- Rehabilitation MedicineUniversity of MinnesotaMinneapolisMN
| | | | - Dawn A Lowe
- Rehabilitation MedicineUniversity of MinnesotaMinneapolisMN
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Nelson DM, Lindsay A, Judge LM, Duan D, Chamberlain JS, Lowe DA, Ervasti JM. Variable rescue of microtubule and physiological phenotypes in mdx muscle expressing different miniaturized dystrophins. Hum Mol Genet 2019; 27:2090-2100. [PMID: 29618008 DOI: 10.1093/hmg/ddy113] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2018] [Accepted: 03/26/2018] [Indexed: 01/08/2023] Open
Abstract
Delivery of miniaturized dystrophin genes via adeno-associated viral vectors is one leading approach in development to treat Duchenne muscular dystrophy. Here we directly compared the functionality of five mini- and micro-dystrophins via skeletal muscle-specific transgenic expression in dystrophin-deficient mdx mice. We evaluated their ability to rescue defects in the microtubule network, passive stiffness and contractility of skeletal muscle. Transgenic mdx mice expressing the short dystrophin isoform Dp116 served as a negative control. All mini- and micro-dystrophins restored elevated detyrosinated α-tubulin and microtubule density of mdx muscle to values not different from C57BL/10, however, only mini-dystrophins restored the transverse component of the microtubule lattice back to C57BL/10. Passive stiffness values in mdx muscles expressing mini- or micro-dystrophins were not different from C57BL/10. While all mini- and micro-dystrophins conferred significant protection from eccentric contraction-induced force loss in vivo and ex vivo compared to mdx, removal of repeats two and three resulted in less protection from force drop caused by eccentric contraction ex vivo. Our data reveal subtle yet significant differences in the relative functionalities for different therapeutic constructs of miniaturized dystrophin in terms of protection from ex vivo eccentric contraction-induced force loss and restoration of an organized microtubule lattice.
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Affiliation(s)
- D'anna M Nelson
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA
| | - Angus Lindsay
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA.,Department of Rehabilitation Medicine, University of Minnesota, Minneapolis, MN 55455, USA
| | - Luke M Judge
- Department of Neurology, University of Washington, Seattle, WA 98195, USA
| | - Dongsheng Duan
- Department of Molecular Microbiology and Immunology, University of Missouri, Columbia, MO 65212, USA
| | | | - Dawn A Lowe
- Department of Rehabilitation Medicine, University of Minnesota, Minneapolis, MN 55455, USA
| | - James M Ervasti
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA
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42
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McCourt JL, Talsness DM, Lindsay A, Arpke RW, Chatterton PD, Nelson DM, Chamberlain CM, Olthoff JT, Belanto JJ, McCourt PM, Kyba M, Lowe DA, Ervasti JM. Mouse models of two missense mutations in actin-binding domain 1 of dystrophin associated with Duchenne or Becker muscular dystrophy. Hum Mol Genet 2019; 27:451-462. [PMID: 29194514 DOI: 10.1093/hmg/ddx414] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2017] [Accepted: 11/17/2017] [Indexed: 01/03/2023] Open
Abstract
Missense mutations in the dystrophin protein can cause Duchenne muscular dystrophy (DMD) or Becker muscular dystrophy (BMD) through an undefined pathomechanism. In vitro studies suggest that missense mutations in the N-terminal actin-binding domain (ABD1) cause protein instability, and cultured myoblast studies reveal decreased expression levels that can be restored to wild-type with proteasome inhibitors. To further elucidate the pathophysiology of missense dystrophin in vivo, we generated two transgenic mdx mouse lines expressing L54R or L172H mutant dystrophin, which correspond to missense mutations identified in human patients with DMD or BMD, respectively. Our biochemical, histologic and physiologic analysis of the L54R and L172H mice show decreased levels of dystrophin which are proportional to the phenotypic severity. Proteasome inhibitors were ineffective in both the L54R and L172H mice, yet mice homozygous for the L172H transgene were able to express even higher levels of dystrophin which caused further improvements in muscle histology and physiology. Given that missense dystrophin is likely being degraded by the proteasome but whole body proteasome inhibition was not possible, we screened for ubiquitin-conjugating enzymes involved in targeting dystrophin to the proteasome. A myoblast cell line expressing L54R mutant dystrophin was screened with an siRNA library targeting E1, E2 and E3 ligases which identified Amn1, FBXO33, Zfand5 and Trim75. Our study establishes new mouse models of dystrophinopathy and identifies candidate E3 ligases that may specifically regulate dystrophin protein turnover in vivo.
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Affiliation(s)
| | - Dana M Talsness
- Department of Biochemistry, Molecular Biology and Biophysics
| | | | - Robert W Arpke
- Department of Pediatrics University of Minnesota - Twin Cities, Minneapolis, MN 55455, USA
| | | | - D'anna M Nelson
- Department of Biochemistry, Molecular Biology and Biophysics
| | | | - John T Olthoff
- Department of Biochemistry, Molecular Biology and Biophysics
| | | | | | - Michael Kyba
- Department of Pediatrics University of Minnesota - Twin Cities, Minneapolis, MN 55455, USA
| | - Dawn A Lowe
- Department of Physical Medicine and Rehabilitation
| | - James M Ervasti
- Department of Biochemistry, Molecular Biology and Biophysics
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Lindsay A, Larson AA, Verma M, Ervasti JM, Lowe DA. Isometric resistance training increases strength and alters histopathology of dystrophin-deficient mouse skeletal muscle. J Appl Physiol (1985) 2018; 126:363-375. [PMID: 30571283 DOI: 10.1152/japplphysiol.00948.2018] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Mutation to the dystrophin gene causes skeletal muscle weakness in patients with Duchenne muscular dystrophy (DMD) or Becker muscular dystrophy (BMD). Deliberation continues regarding implications of prescribing exercise for these patients. The purpose of this study was to determine whether isometric resistance exercise (~10 tetanic contractions/session) improves skeletal muscle strength and histopathology in the mdx mouse model of DMD. Three isometric training sessions increased in vivo isometric torque (22%) and contractility rates (54%) of anterior crural muscles of mdx mice. Mice expressing a BMD-causing missense mutated dystrophin on the mdx background showed comparable increases in torque (22%), while wild-type mice showed less change (11%). Increases in muscle function occurred within 1 h and peaked 3 days posttraining; however, the adaptation was lost after 7 days unless retrained. Six isometric training sessions over 4 wk caused increased isometric torque (28%) and contractility rates (22-28%), reduced fibrosis, as well as greater uniformity of fiber cross-sectional areas, fewer embryonic myosin heavy-chain-positive fibers, and more satellite cells in tibialis anterior muscle compared with the contralateral untrained muscle. Ex vivo functional analysis of isolated extensor digitorum longus (EDL) muscle from the trained hindlimb revealed greater absolute isometric force, lower passive stiffness, and a lower susceptibility to eccentric contraction-induced force loss compared with untrained EDL muscle. Overall, these data support the concept that exercise training in the form of isometric tetanic contractions can improve contractile function of dystrophin-deficient muscle, indicating a potential role for enhancing muscle strength in patients with DMD and BMD. NEW & NOTEWORTHY We focused on adaptive responses of dystrophin-deficient mouse skeletal muscle to isometric contraction training and report that in the absence of dystrophin (or in the presence of a mutated dystrophin), strength and muscle histopathology are improved. Results suggest that the strength gains are associated with fiber hypertrophy, reduced fibrosis, increased number of satellite cells, and blunted eccentric contraction-induced force loss in vitro. Importantly, there was no indication that the isometric exercise training was deleterious to dystrophin-deficient muscle.
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Affiliation(s)
- Angus Lindsay
- Division of Rehabilitation Science and Division of Physical Therapy, Department of Rehabilitation Medicine, University of Minnesota , Minneapolis, Minnesota.,Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota , Minneapolis, Minnesota
| | - Alexie A Larson
- Department of Integrative Biology and Physiology, University of Minnesota , Minneapolis, Minnesota
| | - Mayank Verma
- Department of Integrative Biology and Physiology, University of Minnesota , Minneapolis, Minnesota.,Medical Scientist Training Program, University of Minnesota Medical School , Minneapolis, Minnesota
| | - James M Ervasti
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota , Minneapolis, Minnesota
| | - Dawn A Lowe
- Division of Rehabilitation Science and Division of Physical Therapy, Department of Rehabilitation Medicine, University of Minnesota , Minneapolis, Minnesota
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Lindsay A, McCourt PM, Karachunski P, Lowe DA, Ervasti JM. Xanthine oxidase is hyper-active in Duchenne muscular dystrophy. Free Radic Biol Med 2018; 129:364-371. [PMID: 30312761 PMCID: PMC6599518 DOI: 10.1016/j.freeradbiomed.2018.10.404] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/01/2018] [Revised: 09/21/2018] [Accepted: 10/04/2018] [Indexed: 11/30/2022]
Abstract
Generation of superoxide by xanthine oxidase can be stimulated under ischemic and aberrant calcium homeostasis. Because patients and mice with Duchenne muscular dystrophy (DMD) suffer from ischemia and excessive calcium influx, we tested the hypothesis that xanthine oxidase activity is elevated and contributes to disease pathology. Xanthine oxidase activity was measured by urinary isoxanthopterin in DMD patients at rest and in response to exercise. Urinary isoxanthopterin/creatinine was elevated compared to age-matched controls and Becker muscular dystrophy (BMD) patients. Concentrations were also increased after a six minute walk test in ambulatory patients. We also measured urinary isoxanthopterin in wildtype mice and a number of dystrophic mouse models; the DMD mouse model (mdx), mdx mice overexpressing a variety of transgenic miniaturized and chimeric skeletal muscle-specific dystrophins and utrophin and the β-sarcoglycan deficient (Scgb-/-) mouse which represents type 2E human limb-girdle muscular dystrophy. Mdx and Scgb-/-mice had greater urinary isoxanthopterin/creatinine than wildtype mice while mdx mice expressing dystrophin or utrophin linking the extracellular matrix to the actin cytoskeleton were not different than wildtype. We also measured higher levels of urinary ortho-tyrosine in humans and mice deficient for dystrophin to confirm elevated oxidative stress. Surprisingly, mdx had lower xanthine oxidase protein levels and higher mRNA in gastrocnemius muscle compared to wildtype mice, however, the enzymatic activity of skeletal muscle xanthine oxidase was elevated above wildtype and a transgenic rescued mdx mouse (DysΔMTB-mdx). Downhill treadmill running also caused significant increases in mdx urinary isoxanthopterin that was prevented with the xanthine oxidase inhibitor allopurinol. Similarly, in vitro eccentric contraction-induced force drop of mdx muscle was attenuated by the allopurinol metabolite, oxypurinol. Together, our data suggests hyper-activity of xanthine oxidase in DMD, identifies xanthine oxidase activity as a contributing factor in eccentric contraction-induced force drop of dystrophin-deficient skeletal muscle and highlights the potential of isoxanthopterin as a noninvasive biomarker in DMD.
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MESH Headings
- Adolescent
- Allopurinol/pharmacology
- Animals
- Biomarkers/urine
- Case-Control Studies
- Creatinine/urine
- Dystrophin/deficiency
- Dystrophin/genetics
- Enzyme Inhibitors/pharmacology
- Gene Expression Regulation
- Humans
- Male
- Mice
- Mice, Inbred mdx
- Muscle Contraction/drug effects
- Muscle, Skeletal/drug effects
- Muscle, Skeletal/enzymology
- Muscle, Skeletal/physiopathology
- Muscular Dystrophy, Animal/drug therapy
- Muscular Dystrophy, Animal/enzymology
- Muscular Dystrophy, Animal/genetics
- Muscular Dystrophy, Animal/physiopathology
- Muscular Dystrophy, Duchenne/drug therapy
- Muscular Dystrophy, Duchenne/enzymology
- Muscular Dystrophy, Duchenne/genetics
- Muscular Dystrophy, Duchenne/physiopathology
- Oxypurinol/pharmacology
- Sarcoglycans/deficiency
- Sarcoglycans/genetics
- Tyrosine/urine
- Utrophin/deficiency
- Utrophin/genetics
- Xanthine Oxidase/genetics
- Xanthine Oxidase/urine
- Xanthopterin/urine
- Young Adult
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Affiliation(s)
- Angus Lindsay
- Division of Rehabilitation Science and Division of Physical Therapy, Department of Rehabilitation Medicine, University of Minnesota, Minneapolis, USA; Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, USA.
| | - Preston M McCourt
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, USA
| | - Peter Karachunski
- Department of Pediatrics, University of Minnesota, Minneapolis, USA; Department of Neurology, University of Minnesota, Minneapolis, USA
| | - Dawn A Lowe
- Division of Rehabilitation Science and Division of Physical Therapy, Department of Rehabilitation Medicine, University of Minnesota, Minneapolis, USA
| | - James M Ervasti
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, USA
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45
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Olthoff JT, Lindsay A, Abo-Zahrah R, Baltgalvis KA, Patrinostro X, Belanto JJ, Yu DY, Perrin BJ, Garry DJ, Rodney GG, Lowe DA, Ervasti JM. Loss of peroxiredoxin-2 exacerbates eccentric contraction-induced force loss in dystrophin-deficient muscle. Nat Commun 2018; 9:5104. [PMID: 30504831 PMCID: PMC6269445 DOI: 10.1038/s41467-018-07639-3] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2018] [Accepted: 11/14/2018] [Indexed: 12/28/2022] Open
Abstract
Force loss in skeletal muscle exposed to eccentric contraction is often attributed to injury. We show that EDL muscles from dystrophin-deficient mdx mice recover 65% of lost force within 120 min of eccentric contraction and exhibit minimal force loss when the interval between contractions is increased from 3 to 30 min. A proteomic screen of mdx muscle identified an 80% reduction in the antioxidant peroxiredoxin-2, likely due to proteolytic degradation following hyperoxidation by NADPH Oxidase 2. Eccentric contraction-induced force loss in mdx muscle was exacerbated by peroxiredoxin-2 ablation, and improved by peroxiredoxin-2 overexpression or myoglobin knockout. Finally, overexpression of γcyto- or βcyto-actin protects mdx muscle from eccentric contraction-induced force loss by blocking NADPH Oxidase 2 through a mechanism dependent on cysteine 272 unique to cytoplasmic actins. Our data suggest that eccentric contraction-induced force loss may function as an adaptive circuit breaker that protects mdx muscle from injurious contractions.
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Affiliation(s)
- John T Olthoff
- Molecular, Cellular, Developmental Biology, and Genetics Graduate Program, University of Minnesota, Minneapolis, MN, 55455, USA
| | - Angus Lindsay
- Divisions of Rehabilitation Science and Physical Therapy, Department of Rehabilitation Medicine, University of Minnesota, Minneapolis, MN, 55455, USA
| | - Reem Abo-Zahrah
- Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Kristen A Baltgalvis
- Divisions of Rehabilitation Science and Physical Therapy, Department of Rehabilitation Medicine, University of Minnesota, Minneapolis, MN, 55455, USA
| | - Xiaobai Patrinostro
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, MN, 55455, USA
| | - Joseph J Belanto
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, MN, 55455, USA
| | - Dae-Yeul Yu
- Aging Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Daejeon, Republic of Korea
| | - Benjamin J Perrin
- Department of Biology, Indiana University-Purdue University Indianapolis, Indianapolis, IN, 46022, USA
| | - Daniel J Garry
- Lillehei Heart Institute and Department of Medicine, University of Minnesota, Minneapolis, MN, 55455, USA
| | - George G Rodney
- Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Dawn A Lowe
- Divisions of Rehabilitation Science and Physical Therapy, Department of Rehabilitation Medicine, University of Minnesota, Minneapolis, MN, 55455, USA
| | - James M Ervasti
- Molecular, Cellular, Developmental Biology, and Genetics Graduate Program, University of Minnesota, Minneapolis, MN, 55455, USA.
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, MN, 55455, USA.
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46
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Cabelka CA, Baumann CW, Collins BC, Nash N, Le G, Lindsay A, Spangenburg EE, Lowe DA. Effects of ovarian hormones and estrogen receptor α on physical activity and skeletal muscle fatigue in female mice. Exp Gerontol 2018; 115:155-164. [PMID: 30415069 DOI: 10.1016/j.exger.2018.11.003] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2018] [Revised: 10/17/2018] [Accepted: 11/05/2018] [Indexed: 12/21/2022]
Abstract
Menopause is associated with declines in physical activity and skeletal muscle strength. Physical activity is also reduced in rodents after ovariectomy (OVX) and whole-body estrogen receptor α (ERα) knockout. However, it is unclear if the effects are estradiol (E2) specific. Thus, the overall purpose of this study was to investigate the effects of the ovarian hormones, E2 and progesterone (P4), and skeletal muscle ERα (skmERα) on physical activity and skeletal muscle contractility in female mice. METHODS Study 1: Forty female C57Bl/6J mice were given free access to running wheels for 2 weeks to assess baseline running and randomized into 4 treatment groups: OVX, OVX + E2, OVX + P4, OVX + E2 + P4. All mice underwent OVX, returned to wheels for 2 weeks, received hormone pellet implants and returned to running wheels for 6 weeks, after which soleus muscle contractility testing was completed. Study 2: Thirty-two skeletal muscle specific ERα knock-out (skmERαKO) mice and wildtype (WT) littermates were randomized into 4 groups: skmERαKO-Run, skmERαWT-Run, skmERαKO-Sed, and skmERαWT-Sed. Run mice were given free access to wheels for 20 wk and sedentary (Sed) mice maintained normal cage activities. At the end point, muscle contractility was tested. RESULTS Study 1: OVX + E2 + P4 group ran greater distances than both the OVX and OVX + P4 groups (p ≤ 0.009). After fatiguing contractions, soleus muscles of the OVX + E2 + P4 group maintained greater submaximal force than those of other groups (p = 0.023). Immediately after the fatiguing contractions, OVX + E2 + P4 muscles had greater maximal force production than the OVX + E2 group (p = 0.027). Study 2: There were no differences in running distance between skmERαWT and skmERαKO mice (p = 0.240). Soleus muscles of skmERαKO mice were more fatigable (p < 0.001) and did not recover force as well as skmERαWT mice (p < 0.001). In vivo isometric, concentric and eccentric torque was decreased in skmERαKO mice compared to skmERαWT mice (p ≤ 0.029). CONCLUSIONS Combined treatment of E2 + P4 in OVX mice restored physical activity, predominantly driven by E2, and protected soleus muscles against fatigue. Muscle of skmERαKO mice was weak regardless of physical activity. Although 20 wk of wheel running partially prevented force loss during fatigue in skmERαKO mice, force production during recovery remained low, indicating that estradiol functions through ERα in skeletal muscle.
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Affiliation(s)
- Christine A Cabelka
- Divisions of Rehabilitation Science and Physical Therapy, Department of Rehabilitation Medicine, Medical School, University of Minnesota, Minneapolis, Minnesota; MMC 388, 420 Delaware St SE, Minneapolis, MN 55455, USA
| | - Cory W Baumann
- Divisions of Rehabilitation Science and Physical Therapy, Department of Rehabilitation Medicine, Medical School, University of Minnesota, Minneapolis, Minnesota; MMC 388, 420 Delaware St SE, Minneapolis, MN 55455, USA
| | - Brittany C Collins
- Divisions of Rehabilitation Science and Physical Therapy, Department of Rehabilitation Medicine, Medical School, University of Minnesota, Minneapolis, Minnesota; MMC 388, 420 Delaware St SE, Minneapolis, MN 55455, USA
| | - Nardina Nash
- Divisions of Rehabilitation Science and Physical Therapy, Department of Rehabilitation Medicine, Medical School, University of Minnesota, Minneapolis, Minnesota; MMC 388, 420 Delaware St SE, Minneapolis, MN 55455, USA
| | - Gengyun Le
- Divisions of Rehabilitation Science and Physical Therapy, Department of Rehabilitation Medicine, Medical School, University of Minnesota, Minneapolis, Minnesota; MMC 388, 420 Delaware St SE, Minneapolis, MN 55455, USA
| | - Angus Lindsay
- Divisions of Rehabilitation Science and Physical Therapy, Department of Rehabilitation Medicine, Medical School, University of Minnesota, Minneapolis, Minnesota; MMC 388, 420 Delaware St SE, Minneapolis, MN 55455, USA; Department of Biochemistry Molecular Biology and Biophysics, University of Minnesota, 420 Washington Ave SE, Minneapolis, MN 55455, USA
| | - Espen E Spangenburg
- East Carolina Diabetes and Obesity Institute, Department of Physiology, Brody School of Medicine, East Carolina University, 115 Heart Drive, ECHI - Mail Stop 743, Greenville, NC 27834, USA
| | - Dawn A Lowe
- Divisions of Rehabilitation Science and Physical Therapy, Department of Rehabilitation Medicine, Medical School, University of Minnesota, Minneapolis, Minnesota; MMC 388, 420 Delaware St SE, Minneapolis, MN 55455, USA.
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47
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Levy Y, Ross JA, Niglas M, Snetkov VA, Lynham S, Liao CY, Puckelwartz MJ, Hsu YM, McNally EM, Alsheimer M, Harridge SD, Young SG, Fong LG, Español Y, Lopez-Otin C, Kennedy BK, Lowe DA, Ochala J. Prelamin A causes aberrant myonuclear arrangement and results in muscle fiber weakness. JCI Insight 2018; 3:120920. [PMID: 30282816 PMCID: PMC6237469 DOI: 10.1172/jci.insight.120920] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2018] [Accepted: 08/23/2018] [Indexed: 01/06/2023] Open
Abstract
Physiological and premature aging are frequently associated with an accumulation of prelamin A, a precursor of lamin A, in the nuclear envelope of various cell types. Here, we aimed to underpin the hitherto unknown mechanisms by which prelamin A alters myonuclear organization and muscle fiber function. By experimentally studying membrane-permeabilized myofibers from various transgenic mouse lines, our results indicate that, in the presence of prelamin A, the abundance of nuclei and myosin content is markedly reduced within muscle fibers. This leads to a concept by which the remaining myonuclei are very distant from each other and are pushed to function beyond their maximum cytoplasmic capacity, ultimately inducing muscle fiber weakness.
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Affiliation(s)
- Yotam Levy
- School of Basic and Medical Biosciences, Faculty of Life Sciences & Medicine, and
| | - Jacob A Ross
- School of Basic and Medical Biosciences, Faculty of Life Sciences & Medicine, and
| | - Marili Niglas
- School of Basic and Medical Biosciences, Faculty of Life Sciences & Medicine, and
| | - Vladimir A Snetkov
- School of Basic and Medical Biosciences, Faculty of Life Sciences & Medicine, and
| | - Steven Lynham
- Proteomics Facility, Centre of Excellence for Mass Spectrometry, King's College London, London, United Kingdom
| | - Chen-Yu Liao
- Buck Institute for Research on Aging, Novato, California, USA
| | - Megan J Puckelwartz
- Center for Genetic Medicine, Northwestern University, Chicago, Illinois, USA
| | - Yueh-Mei Hsu
- Buck Institute for Research on Aging, Novato, California, USA
| | - Elizabeth M McNally
- Center for Genetic Medicine, Northwestern University, Chicago, Illinois, USA
| | - Manfred Alsheimer
- Department of Cell and Developmental Biology, University of Würzburg, Würzburg, Germany
| | - Stephen Dr Harridge
- School of Basic and Medical Biosciences, Faculty of Life Sciences & Medicine, and
| | - Stephen G Young
- Department of Medicine, University of California Los Angeles, Los Angeles, California, USA
| | - Loren G Fong
- Department of Medicine, University of California Los Angeles, Los Angeles, California, USA
| | - Yaiza Español
- Departamento de Bioquímica y Biología Molecular, Facultad de Medicina, Instituto Universitario de Oncología (IUOPA), Universidad de Oviedo, Oviedo, Spain
| | - Carlos Lopez-Otin
- Departamento de Bioquímica y Biología Molecular, Facultad de Medicina, Instituto Universitario de Oncología (IUOPA), Universidad de Oviedo, Oviedo, Spain.,Centro de Investigación Biomédica en Red de Cáncer (CIBERONC), Spain
| | - Brian K Kennedy
- Buck Institute for Research on Aging, Novato, California, USA.,Departments of Biochemistry and Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore.,Centre for Healthy Ageing, National University Health System, Singapore.,Singapore Institute for Clinical Sciences, Singapore
| | - Dawn A Lowe
- Divisions of Rehabilitation Science and Physical Therapy, Department of Rehabilitation Medicine, School of Medicine, University of Minnesota, Minneapolis, Minnesota, USA
| | - Julien Ochala
- School of Basic and Medical Biosciences, Faculty of Life Sciences & Medicine, and
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48
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Le G, Novotny SA, Mader TL, Greising SM, Chan SSK, Kyba M, Lowe DA, Warren GL. A moderate oestradiol level enhances neutrophil number and activity in muscle after traumatic injury but strength recovery is accelerated. J Physiol 2018; 596:4665-4680. [PMID: 30035314 PMCID: PMC6166067 DOI: 10.1113/jp276432] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2018] [Accepted: 07/09/2018] [Indexed: 12/18/2022] Open
Abstract
KEY POINTS The female hormone oestrogen may protect muscle from injury by reducing inflammation but this is debatable. In this study, the inflammatory response of injured muscle from oestrogen-replete mice was comprehensively compared to that from oestrogen-deficient mice. We show that oestrogen markedly promotes movement of neutrophils, an inflammatory white blood cell type, into muscle over the first few days after injury but has only a minor effect on the movement of macrophages, another inflammatory cell type. Despite the enhancement of inflammation by oestrogen in injured muscle, we found strength in oestrogen-replete mice to recover faster and to a greater extent than it does in oestrogen-deficient mice. Our study and others indicate that lower doses of oestrogen, such as that used in our study, may affect muscle inflammation and injury differently from higher doses. ABSTRACT Oestrogen has been shown to protect against skeletal muscle injury and a reduced inflammatory response has been suggested as a possible protective mechanism. There are, however, dissenting reports. Our objective was to conduct an unbiased, comprehensive study of the effect of oestradiol on the inflammatory response following muscle injury. Female C57BL6/J mice were ovariectomized and supplemented with and without oestradiol. Tibialis anterior muscles were freeze injured and studied primarily at 1-4 days post-injury. Oestradiol supplementation increased injured muscle gene expression of neutrophil chemoattractants (Cxcl1 and Cxcl5) and to a lesser extent that of monocyte/macrophage chemoattractants (Ccl2 and Spp1). Oestradiol markedly increased gene expression of the neutrophil cell surface marker (Ly6g) but had less consistent effects on the monocyte/macrophage cell surface markers (Cd68, Cd163 and Cd206). These results were confirmed at the protein level by immunoblot with oestradiol increasing LY6G/C content and having no significant effect on CD163 content. These findings were confirmed with fluorescence-activated cell sorting counts of neutrophils and macrophages in injured muscles; oestradiol increased the proportion of CD45+ cells that were neutrophils (LY6G+ ) but not the proportion that were macrophages (CD68+ or CD206+ ). Physiological impact of the oestradiol-enhanced neutrophil response was assessed by strength measurements. There was no significant difference in strength between oestradiol-supplemented and -unsupplemented mice until 2 weeks post-injury; strength was 13-24% greater in supplemented mice at 2-6 weeks post-injury. In conclusion, a moderate level of oestradiol supplementation enhances neutrophil infiltration in injured muscle and this is associated with a beneficial effect on strength recovery.
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Affiliation(s)
- Gengyun Le
- Divisions of Rehabilitation Science and Physical Therapy, Department of Rehabilitation MedicineUniversity of Minnesota Medical SchoolMinneapolisMNUSA
| | - Susan A. Novotny
- Divisions of Rehabilitation Science and Physical Therapy, Department of Rehabilitation MedicineUniversity of Minnesota Medical SchoolMinneapolisMNUSA
| | - Tara L. Mader
- Divisions of Rehabilitation Science and Physical Therapy, Department of Rehabilitation MedicineUniversity of Minnesota Medical SchoolMinneapolisMNUSA
| | - Sarah M. Greising
- Divisions of Rehabilitation Science and Physical Therapy, Department of Rehabilitation MedicineUniversity of Minnesota Medical SchoolMinneapolisMNUSA
| | - Sunny S. K. Chan
- Lillehei Heart InstituteUniversity of MinnesotaMinneapolisMNUSA
- Department of PediatricsUniversity of MinnesotaMinneapolisMNUSA
| | - Michael Kyba
- Lillehei Heart InstituteUniversity of MinnesotaMinneapolisMNUSA
- Department of PediatricsUniversity of MinnesotaMinneapolisMNUSA
| | - Dawn A. Lowe
- Divisions of Rehabilitation Science and Physical Therapy, Department of Rehabilitation MedicineUniversity of Minnesota Medical SchoolMinneapolisMNUSA
| | - Gordon L. Warren
- Department of Physical TherapyGeorgia State UniversityAtlantaGAUSA
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49
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Phung LA, Karvinen SM, Colson BA, Thomas DD, Lowe DA. Age affects myosin relaxation states in skeletal muscle fibers of female but not male mice. PLoS One 2018; 13:e0199062. [PMID: 30226869 PMCID: PMC6143227 DOI: 10.1371/journal.pone.0199062] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2018] [Accepted: 09/03/2018] [Indexed: 12/16/2022] Open
Abstract
The recent discovery that myosin has two distinct states in relaxed muscle–disordered relaxed (DRX) and super-relaxed (SRX)–provides another factor to consider in our fundamental understanding of the aging mechanism in skeletal muscle, since myosin is thought to be a potential contributor to dynapenia (age-associated loss of muscle strength independent of atrophy). The primary goal of this study was to determine the effects of age on DRX and SRX states and to examine their sex specificity. We have used quantitative fluorescence microscopy of the fluorescent nucleotide analog 2′/3′-O-(N-methylanthraniloyl) ATP (mantATP) to measure single-nucleotide turnover kinetics of myosin in skinned skeletal muscle fibers under relaxing conditions. We examined changes in DRX and SRX in response to the natural aging process by measuring the turnover of mantATP in skinned fibers isolated from psoas muscle of adult young (3–4 months old) and aged (26–28 months old) C57BL/6 female and male mice. Fluorescence decays were fitted to a multi-exponential decay function to determine both the time constants and mole fractions of fast and slow turnover populations, and significance was analyzed by a t-test. We found that in females, both the DRX and SRX lifetimes of myosin ATP turnover at steady state were shorter in aged muscle fibers compared to young muscle fibers (p ≤ 0.033). However, there was no significant difference in relaxation lifetime of either DRX (p = 0.202) or SRX (p = 0.804) between young and aged male mice. No significant effects were measured on the mole fractions (populations) of these states, as a function of sex or age (females, p = 0.100; males, p = 0.929). The effect of age on the order of myosin heads at rest and their ATPase function is sex specific, affecting only females. These findings provide new insight into the molecular factors and mechanisms that contribute to aging muscle dysfunction in a sex-specific manner.
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Affiliation(s)
- Lien A. Phung
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, Minnesota, United States of America
| | - Sira M. Karvinen
- Department of Rehabilitation Medicine, University of Minnesota, Minneapolis, Minnesota, United States of America
| | - Brett A. Colson
- Department of Cellular and Molecular Medicine, University of Arizona, Tucson, Arizona, United States of America
| | - David D. Thomas
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, Minnesota, United States of America
- * E-mail: (DDT); (DAL)
| | - Dawn A. Lowe
- Department of Rehabilitation Medicine, University of Minnesota, Minneapolis, Minnesota, United States of America
- * E-mail: (DDT); (DAL)
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50
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Nelson DM, Lindsay A, Judge LM, Duan D, Chamberlain JS, Lowe DA, Ervasti JM. Variable rescue of microtubule and physiological phenotypes in mdx muscle expressing different miniaturized dystrophins. Hum Mol Genet 2018; 27:2773. [PMID: 29901725 DOI: 10.1093/hmg/ddy209] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- D'anna M Nelson
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN, USA
| | - Angus Lindsay
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN, USA.,Department of Rehabilitation Medicine, University of Minnesota, Minneapolis, MN, USA
| | - Luke M Judge
- Department of Neurology, University of Washington, Seattle, WA, USA
| | - Dongsheng Duan
- Department of Molecular Microbiology and Immunology, University of Missouri, Columbia, MO, USA
| | | | - Dawn A Lowe
- Department of Rehabilitation Medicine, University of Minnesota, Minneapolis, MN, USA
| | - James M Ervasti
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN, USA
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