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Du XJ, She G, Wu W, Deng XL. Coupling of β-adrenergic and Hippo pathway signaling: Implications for heart failure pathophysiology and metabolic therapy. Mitochondrion 2024; 78:101941. [PMID: 39122227 DOI: 10.1016/j.mito.2024.101941] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2024] [Revised: 07/17/2024] [Accepted: 08/03/2024] [Indexed: 08/12/2024]
Abstract
Activation of the sympatho-β-adrenergic receptor (βAR) system is the hallmark of heart disease with adverse consequences that facilitate the onset and progression of heart failure (HF). Use of β-blocking drugs has become the front-line therapy for HF. Last decade has witnessed progress in research demonstrating a pivotal role of Hippo pathway in cardiomyopathy and HF. Clinical studies have revealed myocardial Hippo pathway activation/YAP-TEAD1 inactivation in several types of human cardiomyopathy. Experimental activation of cardiac Hippo signaling or inhibition of YAP-TEAD1 have been shown to leads dilated cardiomyopathy with severe mitochondrial dysfunction and metabolic reprogramming. Studies have also convincingly shown that stimulation of βAR activates cardiac Hippo pathway with inactivation of the down-stream effector molecules YAP/TAZ. There is strong evidence for the adverse consequences of the βAR-Hippo signaling leading to HF. In addition to promoting cardiomyocyte death and fibrosis, recent progress is the demonstration of mitochondrial dysfunction and metabolic reprogramming mediated by βAR-Hippo pathway signaling. Activation of cardiac βAR-Hippo signaling is potent in downregulating a range of mitochondrial and metabolic genes, whereas expression of pro-inflammatory and pro-fibrotic factors are upregulated. Coupling of βAR-Hippo pathway signaling is mediated by several kinases, mechanotransduction and/or Ca2+ signaling, and can be blocked by β-antagonists. Demonstration of the converge of βAR signaling and Hippo pathway bears implications for a better understanding on the role of enhanced sympathetic nervous activity, efficacy of β-antagonists, and metabolic therapy targeting this pathway in HF. In this review we summarize the progress and discuss future research directions in this field.
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Affiliation(s)
- Xiao-Jun Du
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, and Key Laboratory of Environment and Genes Related to Diseases, Ministry of Education, Xi'an Jiaotong University Health Science Center, 76 West Yanta Road, Xi'an, Shaanxi 710061, China; Baker Heart and Diabetes Institute, 75 Commercial Road, Melbourne, Victoria 3004, Australia,.
| | - Gang She
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, and Key Laboratory of Environment and Genes Related to Diseases, Ministry of Education, Xi'an Jiaotong University Health Science Center, 76 West Yanta Road, Xi'an, Shaanxi 710061, China
| | - Wei Wu
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, and Key Laboratory of Environment and Genes Related to Diseases, Ministry of Education, Xi'an Jiaotong University Health Science Center, 76 West Yanta Road, Xi'an, Shaanxi 710061, China; Department of Cardiology, Shaanxi Provincial Hospital and the Third Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi, China
| | - Xiu-Ling Deng
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, and Key Laboratory of Environment and Genes Related to Diseases, Ministry of Education, Xi'an Jiaotong University Health Science Center, 76 West Yanta Road, Xi'an, Shaanxi 710061, China
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2
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Helzer D, Kannan P, Reynolds JC, Gibbs DE, Crosbie RH. Role of microenvironment on muscle stem cell function in health, adaptation, and disease. Curr Top Dev Biol 2024; 158:179-201. [PMID: 38670705 DOI: 10.1016/bs.ctdb.2024.02.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/28/2024]
Abstract
The role of the cellular microenvironment has recently gained attention in the context of muscle health, adaption, and disease. Emerging evidence supports major roles for the extracellular matrix (ECM) in regeneration and the dynamic regulation of the satellite cell niche. Satellite cells normally reside in a quiescent state in healthy muscle, but upon muscle injury, they activate, proliferate, and fuse to the damaged fibers to restore muscle function and architecture. This chapter reviews the composition and mechanical properties of skeletal muscle ECM and the role of these factors in contributing to the satellite cell niche that impact muscle regeneration. In addition, the chapter details the effects of satellite cell-matrix interactions and provides evidence that there is bidirectional regulation affecting both the cellular and extracellular microenvironment within skeletal muscle. Lastly, emerging methods to investigate satellite cell-matrix interactions will be presented.
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Affiliation(s)
- Daniel Helzer
- Department of Integrative Biology and Physiology, University of California, Los Angeles, Los Angeles, CA, United States
| | - Pranav Kannan
- Department of Integrative Biology and Physiology, University of California, Los Angeles, Los Angeles, CA, United States
| | - Joseph C Reynolds
- Department of Integrative Biology and Physiology, University of California, Los Angeles, Los Angeles, CA, United States
| | - Devin E Gibbs
- Department of Integrative Biology and Physiology, University of California, Los Angeles, Los Angeles, CA, United States; Molecular Biology Institute, University of California, Los Angeles, Los Angeles, CA, United States
| | - Rachelle H Crosbie
- Department of Integrative Biology and Physiology, University of California, Los Angeles, Los Angeles, CA, United States; Molecular Biology Institute, University of California, Los Angeles, Los Angeles, CA, United States; Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research, University of California, Los Angeles, Los Angeles, CA, United States; Department of Neurology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, United States.
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3
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Sciandra F, Bozzi M, Bigotti MG. From adhesion complex to signaling hub: the dual role of dystroglycan. Front Mol Biosci 2023; 10:1325284. [PMID: 38155958 PMCID: PMC10752950 DOI: 10.3389/fmolb.2023.1325284] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2023] [Accepted: 11/27/2023] [Indexed: 12/30/2023] Open
Abstract
Dystroglycan (DG) is a transmembrane protein widely expressed in multiple cells and tissues. It is formed by two subunits, α- and β-DG, and represents a molecular bridge between the outside and the inside of the cell, which is essential for the mechanical and structural stability of the plasma membrane. The α-subunit is a cell-surface protein that binds to the extracellular matrix (ECM) and is tightly associated with the plasma membrane via a non-covalent interaction with the β-subunit, which, in turn, is a transmembrane protein that binds to the cytoskeletal actin. DG is a versatile molecule acting not only as a mechanical building block but also as a modulator of outside-inside signaling events. The cytoplasmic domain of β-DG interacts with different adaptor and cytoskeletal proteins that function as molecular switches for the transmission of ECM signals inside the cells. These interactions can modulate the involvement of DG in different biological processes, ranging from cell growth and survival to differentiation and proliferation/regeneration. Although the molecular events that characterize signaling through the ECM-DG-cytoskeleton axis are still largely unknown, in recent years, a growing list of evidence has started to fill the gaps in our understanding of the role of DG in signal transduction. This mini-review represents an update of recent developments, uncovering the dual role of DG as an adhesion and signaling molecule that might inspire new ideas for the design of novel therapeutic strategies for pathologies such as muscular dystrophy, cardiomyopathy, and cancer, where the DG signaling hub plays important roles.
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Affiliation(s)
- Francesca Sciandra
- Istituto di Scienze e Tecnologie Chimiche “Giulio Natta”-SCITEC (CNR), Roma, Italy
| | - Manuela Bozzi
- Istituto di Scienze e Tecnologie Chimiche “Giulio Natta”-SCITEC (CNR), Roma, Italy
- Dipartimento di Scienze Biotecnologiche di Base, Cliniche Intensivologiche e Perioperatorie, Sezione di Biochimica, Università Cattolica del Sacro Cuore di Roma, Roma, Italy
| | - Maria Giulia Bigotti
- School of Biochemistry, University of Bristol, Bristol, United Kingdom
- Bristol Heart Institute, Research Floor Level 7, Bristol Royal Infirmary, Bristol, United Kingdom
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4
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Jung SY, Riew TR, Yun HH, Lim JH, Hwang JW, Jung SW, Kim HL, Lee JS, Lee MY, Lee JH. Skeletal Muscle-Specific Bis Depletion Leads to Muscle Dysfunction and Early Death Accompanied by Impairment in Protein Quality Control. Int J Mol Sci 2023; 24:ijms24119635. [PMID: 37298584 DOI: 10.3390/ijms24119635] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2023] [Revised: 05/25/2023] [Accepted: 05/30/2023] [Indexed: 06/12/2023] Open
Abstract
Bcl-2-interacting cell death suppressor (BIS), also called BAG3, plays a role in physiological functions such as anti-apoptosis, cell proliferation, autophagy, and senescence. Whole-body Bis-knockout (KO) mice exhibit early lethality accompanied by abnormalities in cardiac and skeletal muscles, suggesting the critical role of BIS in these muscles. In this study, we generated skeletal muscle-specific Bis-knockout (Bis-SMKO) mice for the first time. Bis-SMKO mice exhibit growth retardation, kyphosis, a lack of peripheral fat, and respiratory failure, ultimately leading to early death. Regenerating fibers and increased intensity in cleaved PARP1 immunostaining were observed in the diaphragm of Bis-SMKO mice, indicating considerable muscle degeneration. Through electron microscopy analysis, we observed myofibrillar disruption, degenerated mitochondria, and autophagic vacuoles in the Bis-SMKO diaphragm. Specifically, autophagy was impaired, and heat shock proteins (HSPs), such as HSPB5 and HSP70, and z-disk proteins, including filamin C and desmin, accumulated in Bis-SMKO skeletal muscles. We also found metabolic impairments, including decreased ATP levels and lactate dehydrogenase (LDH) and creatine kinase (CK) activities in the diaphragm of Bis-SMKO mice. Our findings highlight that BIS is critical for protein homeostasis and energy metabolism in skeletal muscles, suggesting that Bis-SMKO mice could be used as a therapeutic strategy for myopathies and to elucidate the molecular function of BIS in skeletal muscle physiology.
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Affiliation(s)
- Soon-Young Jung
- Department of Biochemistry, College of Medicine, The Catholic University of Korea, Seoul 06591, Republic of Korea
- Institute for Aging and Metabolic Diseases, College of Medicine, The Catholic University of Korea, Seoul 06591, Republic of Korea
| | - Tae-Ryong Riew
- Department of Anatomy, Catholic Neuroscience Institute, College of Medicine, The Catholic University of Korea, Seoul 06591, Republic of Korea
| | - Hye Hyeon Yun
- Department of Biochemistry, College of Medicine, The Catholic University of Korea, Seoul 06591, Republic of Korea
- Institute for Aging and Metabolic Diseases, College of Medicine, The Catholic University of Korea, Seoul 06591, Republic of Korea
| | - Ji Hee Lim
- Division of Nephrology, Department of Internal Medicine, College of Medicine, The Catholic University of Korea, Seoul 06591, Republic of Korea
| | - Ji-Won Hwang
- Department of Anatomy, Catholic Neuroscience Institute, College of Medicine, The Catholic University of Korea, Seoul 06591, Republic of Korea
| | - Sung Won Jung
- Department of Anatomy, Catholic Neuroscience Institute, College of Medicine, The Catholic University of Korea, Seoul 06591, Republic of Korea
| | - Hong Lim Kim
- Integrative Research Support Center, Laboratory of Electron Microscope, College of Medicine, The Catholic University of Korea, Seoul 06591, Republic of Korea
| | - Jae-Seon Lee
- Research Center for Controlling Intercellular Communication (RCIC), College of Medicine, Inha University, Incheon 22212, Republic of Korea
- Program in Biomedical Science & Engineering, Inha University, Incheon 22212, Republic of Korea
| | - Mun-Yong Lee
- Department of Anatomy, Catholic Neuroscience Institute, College of Medicine, The Catholic University of Korea, Seoul 06591, Republic of Korea
| | - Jeong-Hwa Lee
- Department of Biochemistry, College of Medicine, The Catholic University of Korea, Seoul 06591, Republic of Korea
- Institute for Aging and Metabolic Diseases, College of Medicine, The Catholic University of Korea, Seoul 06591, Republic of Korea
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5
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Choi Y, Morlino G, Toboso-Navasa A, Hopf R, Pramotton FM, Bigot A, Taddei A, Cesarovic N, Falk V, Mazza E, Giampietro C. A novel bistable device to study mechanosensitive cell responses to instantaneous stretch. BIOMATERIALS ADVANCES 2022; 141:213134. [PMID: 36191540 DOI: 10.1016/j.bioadv.2022.213134] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2022] [Revised: 08/17/2022] [Accepted: 09/25/2022] [Indexed: 06/16/2023]
Abstract
The behavior of cells and tissues in vivo is determined by the integration of multiple biochemical and mechanical signals. Of the mechanical signals, stretch has been studied for decades and shown to contribute to pathophysiological processes. Several different stretch devices have been developed for in vitro investigations of cell stretch. In this work, we describe a new 3D-printed uniaxial stretching device for studying cell response to rapid deformation. The device is a bistable compliant mechanism holding two equilibrium states-an unstretched and stretched configuration-without the need of an external actuator. Furthermore, it allows multiple simultaneous measurements of different levels of stretch on a single substrate and is compatible with standard immunofluorescence imaging of fixed cells as well as live-cell imaging. To demonstrate the effectiveness of the device to stretch cells, a test case using aligned myotubes is presented. Leveraging material area changes associated with deformation of the substrate, changes in nuclei density provided evidence of affine deformation between cells and substrate. Furthermore, intranuclear deformations were also assessed and shown to deform non-affinely. As a proof-of-principle of the use of the device for mechanobiological studies, we uniaxially stretched aligned healthy and dystrophic myotubes that displayed different passive mechanical responses, consistent with previous literature in the field. We also identified a new feature in the mechanoresponse of dystrophic myotubes, which is of potential interest for identifying the diseased cells based on a quick mechanical readout. While some applications of the device for elucidating passive mechanical responses are demonstrated, the simplicity of the device allows it to be potentially used for other modes of deformation with little modifications.
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Affiliation(s)
- Young Choi
- Department of Mechanical and Process Engineering, ETH Zurich, Zurich 8092, Switzerland
| | | | | | - Raoul Hopf
- Department of Mechanical and Process Engineering, ETH Zurich, Zurich 8092, Switzerland; Swiss Federal Laboratories for Materials Science and Technology (EMPA), Dübendorf 8600, Switzerland; Senecell AG, Zurich 8057, Switzerland
| | - Francesca Michela Pramotton
- Department of Mechanical and Process Engineering, ETH Zurich, Zurich 8092, Switzerland; Swiss Federal Laboratories for Materials Science and Technology (EMPA), Dübendorf 8600, Switzerland
| | - Anne Bigot
- Sorbonne Université, Inserm, Institut de Myologie, Centre de Recherche en Myologie, F-75013 Paris, France
| | | | - Nikola Cesarovic
- Department of Health Sciences and Technology, ETH Zurich, Zurich 8092, Switzerland; Charité - Universitätsmedizin Berlin, Berlin 10117, Germany
| | - Volkmar Falk
- Department of Health Sciences and Technology, ETH Zurich, Zurich 8092, Switzerland; Charité - Universitätsmedizin Berlin, Berlin 10117, Germany
| | - Edoardo Mazza
- Department of Mechanical and Process Engineering, ETH Zurich, Zurich 8092, Switzerland; Swiss Federal Laboratories for Materials Science and Technology (EMPA), Dübendorf 8600, Switzerland.
| | - Costanza Giampietro
- Department of Mechanical and Process Engineering, ETH Zurich, Zurich 8092, Switzerland; Swiss Federal Laboratories for Materials Science and Technology (EMPA), Dübendorf 8600, Switzerland; Senecell AG, Zurich 8057, Switzerland.
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6
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Hinkle ER, Blue RE, Tsai YH, Combs M, Davi J, Coffey AR, Boriek AM, Taylor JM, Parker JS, Giudice J. Stretching muscle cells induces transcriptional and splicing transitions and changes in SR proteins. Commun Biol 2022; 5:987. [PMID: 36123433 PMCID: PMC9485123 DOI: 10.1038/s42003-022-03915-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2022] [Accepted: 08/30/2022] [Indexed: 11/08/2022] Open
Abstract
Alternative splicing is an RNA processing mechanism involved in skeletal muscle development and pathology. Muscular diseases exhibit splicing alterations and changes in mechanobiology leading us to investigate the interconnection between mechanical forces and RNA processing. We performed deep RNA-sequencing after stretching muscle cells. First, we uncovered transcriptional changes in genes encoding proteins involved in muscle function and transcription. Second, we observed that numerous mechanosensitive genes were part of the MAPK pathway which was activated in response to stretching. Third, we revealed that stretching skeletal muscle cells increased the proportion of alternatively spliced cassette exons and their inclusion. Fourth, we demonstrated that the serine and arginine-rich proteins exhibited stronger transcriptional changes than other RNA-binding proteins and that SRSF4 phosphorylation is mechanosensitive. Identifying SRSF4 as a mechanosensitive RNA-binding protein that might contribute to crosstalk between mechanotransduction, transcription, and splicing could potentially reveal novel insights into muscular diseases, particularly those with unknown etiologies.
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Affiliation(s)
- Emma R Hinkle
- Department of Cell Biology and Physiology, The University of North Carolina at Chapel Hill, Chapel Hill, 27599, NC, USA
- Curriculum in Genetics and Molecular Biology (GMB), The University of North Carolina at Chapel Hill, Chapel Hill, 27599, NC, USA
| | - R Eric Blue
- Department of Cell Biology and Physiology, The University of North Carolina at Chapel Hill, Chapel Hill, 27599, NC, USA
| | - Yi-Hsuan Tsai
- Lineberger Comprehensive Cancer Center, The University of North Carolina at Chapel Hill, Chapel Hill, 27599, NC, USA
| | - Matthew Combs
- Department of Pathology and Laboratory Medicine, The University of North Carolina at Chapel Hill, Chapel Hill, 27599, NC, USA
| | - Jacquelyn Davi
- Department of Cell Biology and Physiology, The University of North Carolina at Chapel Hill, Chapel Hill, 27599, NC, USA
| | - Alisha R Coffey
- Lineberger Comprehensive Cancer Center, The University of North Carolina at Chapel Hill, Chapel Hill, 27599, NC, USA
| | - Aladin M Boriek
- Department of Medicine, Baylor College of Medicine, Houston, TX, USA
| | - Joan M Taylor
- Department of Pathology and Laboratory Medicine, The University of North Carolina at Chapel Hill, Chapel Hill, 27599, NC, USA
- McAllister Heart Institute, The University of North Carolina at Chapel Hill, Chapel Hill, 27599, NC, USA
| | - Joel S Parker
- Curriculum in Genetics and Molecular Biology (GMB), The University of North Carolina at Chapel Hill, Chapel Hill, 27599, NC, USA
- Lineberger Comprehensive Cancer Center, The University of North Carolina at Chapel Hill, Chapel Hill, 27599, NC, USA
| | - Jimena Giudice
- Department of Cell Biology and Physiology, The University of North Carolina at Chapel Hill, Chapel Hill, 27599, NC, USA.
- Curriculum in Genetics and Molecular Biology (GMB), The University of North Carolina at Chapel Hill, Chapel Hill, 27599, NC, USA.
- McAllister Heart Institute, The University of North Carolina at Chapel Hill, Chapel Hill, 27599, NC, USA.
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7
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Dystrophin missense mutations alter focal adhesion tension and mechanotransduction. Proc Natl Acad Sci U S A 2022; 119:e2205536119. [PMID: 35700360 PMCID: PMC9231619 DOI: 10.1073/pnas.2205536119] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Skeletal muscle is a mechanical organ that not only produces force but also uses mechanical stimuli as a signal to regulate cellular responses. Duchenne and Becker muscular dystrophy are lethal muscle wasting diseases that affect 1 in 3,500 boys and is caused by the absence or malfunction of dystrophin protein, respectively. There is a lack of understanding on how the integration of these mechanical signals is dysregulated in muscular dystrophy and how they may contribute to disease progression. In this study, we show that patient-relevant dystrophin mutations alter the mechanical signaling axis in muscle cells, leading to impaired migration. This work proposes dystrophin as a component of the cellular force-sensing machinery, furthering our knowledge in the pathomechanism of muscular dystrophy. Dystrophin is an essential muscle protein that contributes to cell membrane stability by mechanically linking the actin cytoskeleton to the extracellular matrix via an adhesion complex called the dystrophin–glycoprotein complex. The absence or impaired function of dystrophin causes muscular dystrophy. Focal adhesions (FAs) are also mechanosensitive adhesion complexes that connect the cytoskeleton to the extracellular matrix. However, the interplay between dystrophin and FA force transmission has not been investigated. Using a vinculin-based bioluminescent tension sensor, we measured FA tension in transgenic C2C12 myoblasts expressing wild-type (WT) dystrophin, a nonpathogenic single nucleotide polymorphism (SNP) (I232M), or two missense mutations associated with Duchenne (L54R), or Becker muscular dystrophy (L172H). Our data revealed cross talk between dystrophin and FAs, as the expression of WT or I232M dystrophin increased FA tension compared to dystrophin-less nontransgenic myoblasts. In contrast, the expression of L54R or L172H did not increase FA tension, indicating that these disease-causing mutations compromise the mechanical function of dystrophin as an FA allosteric regulator. Decreased FA tension caused by these mutations manifests as defective migration, as well as decreased Yes-associated protein 1 (YAP) activation, possibly by the disruption of the ability of FAs to transmit forces between the extracellular matrix and cytoskeleton. Our results indicate that dystrophin influences FA tension and suggest that dystrophin disease-causing missense mutations may disrupt a cellular tension-sensing pathway in dystrophic skeletal muscle.
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8
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Solís C, Russell B. Striated muscle proteins are regulated both by mechanical deformation and by chemical post-translational modification. Biophys Rev 2021; 13:679-695. [PMID: 34777614 PMCID: PMC8555064 DOI: 10.1007/s12551-021-00835-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2021] [Accepted: 08/23/2021] [Indexed: 01/09/2023] Open
Abstract
All cells sense force and build their cytoskeleton to optimize function. How is this achieved? Two major systems are involved. The first is that load deforms specific protein structures in a proportional and orientation-dependent manner. The second is post-translational modification of proteins as a consequence of signaling pathway activation. These two processes work together in a complex way so that local subcellular assembly as well as overall cell function are controlled. This review discusses many cell types but focuses on striated muscle. Detailed information is provided on how load deforms the structure of proteins in the focal adhesions and filaments, using α-actinin, vinculin, talin, focal adhesion kinase, LIM domain-containing proteins, filamin, myosin, titin, and telethonin as examples. Second messenger signals arising from external triggers are distributed throughout the cell causing post-translational or chemical modifications of protein structures, with the actin capping protein CapZ and troponin as examples. There are numerous unanswered questions of how mechanical and chemical signals are integrated by muscle proteins to regulate sarcomere structure and function yet to be studied. Therefore, more research is needed to see how external triggers are integrated with local tension generated within the cell. Nonetheless, maintenance of tension in the sarcomere is the essential and dominant mechanism, leading to the well-known phrase in exercise physiology: "use it or lose it."
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Affiliation(s)
- Christopher Solís
- Department of Physiology and Biophysics, College of Medicine, University of Illinois at Chicago, Chicago, IL 60612 USA
| | - Brenda Russell
- Department of Physiology and Biophysics, College of Medicine, University of Illinois at Chicago, Chicago, IL 60612 USA
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9
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The Neuromuscular Junction: Roles in Aging and Neuromuscular Disease. Int J Mol Sci 2021; 22:ijms22158058. [PMID: 34360831 PMCID: PMC8347593 DOI: 10.3390/ijms22158058] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2021] [Revised: 07/20/2021] [Accepted: 07/22/2021] [Indexed: 02/07/2023] Open
Abstract
The neuromuscular junction (NMJ) is a specialized synapse that bridges the motor neuron and the skeletal muscle fiber and is crucial for conversion of electrical impulses originating in the motor neuron to action potentials in the muscle fiber. The consideration of contributing factors to skeletal muscle injury, muscular dystrophy and sarcopenia cannot be restricted only to processes intrinsic to the muscle, as data show that these conditions incur denervation-like findings, such as fragmented NMJ morphology and corresponding functional changes in neuromuscular transmission. Primary defects in the NMJ also influence functional loss in motor neuron disease, congenital myasthenic syndromes and myasthenia gravis, resulting in skeletal muscle weakness and heightened fatigue. Such findings underscore the role that the NMJ plays in neuromuscular performance. Regardless of cause or effect, functional denervation is now an accepted consequence of sarcopenia and muscle disease. In this short review, we provide an overview of the pathologic etiology, symptoms, and therapeutic strategies related to the NMJ. In particular, we examine the role of the NMJ as a disease modifier and a potential therapeutic target in neuromuscular injury and disease.
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10
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Cai X, Wang KC, Meng Z. Mechanoregulation of YAP and TAZ in Cellular Homeostasis and Disease Progression. Front Cell Dev Biol 2021; 9:673599. [PMID: 34109179 PMCID: PMC8182050 DOI: 10.3389/fcell.2021.673599] [Citation(s) in RCA: 96] [Impact Index Per Article: 32.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2021] [Accepted: 04/30/2021] [Indexed: 12/12/2022] Open
Abstract
Biophysical cues, such as mechanical properties, play a critical role in tissue growth and homeostasis. During organ development and tissue injury repair, compressive and tensional forces generated by cell-extracellular matrix or cell-cell interaction are key factors for cell fate determination. In the vascular system, hemodynamic forces, shear stress, and cyclic stretch modulate vascular cell phenotypes and susceptibility to atherosclerosis. Despite that emerging efforts have been made to investigate how mechanotransduction is involved in tuning cell and tissue functions in various contexts, the regulatory mechanisms remain largely unknown. One of the challenges is to understand the signaling cascades that transmit mechanical cues from the plasma membrane to the cytoplasm and then to the nuclei to generate mechanoresponsive transcriptomes. YAP and its homolog TAZ, the Hippo pathway effectors, have been identified as key mechanotransducers that sense mechanical stimuli and relay the signals to control transcriptional programs for cell proliferation, differentiation, and transformation. However, the upstream mechanosensors for YAP/TAZ signaling and downstream transcriptome responses following YAP/TAZ activation or repression have not been well characterized. Moreover, the mechanoregulation of YAP/TAZ in literature is highly context-dependent. In this review, we summarize the biomechanical cues in the tissue microenvironment and provide an update on the roles of YAP/TAZ in mechanotransduction in various physiological and pathological conditions.
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Affiliation(s)
- Xiaomin Cai
- Department of Oncology, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China
| | - Kuei-Chun Wang
- School of Biological and Health Systems Engineering, Arizona State University, Tempe, AZ, United States
| | - Zhipeng Meng
- Department of Molecular and Cellular Pharmacology, University of Miami Miller School of Medicine, Miami, FL, United States
- Sylvester Comprehensive Cancer Center, University of Miami Miller School of Medicine, Miami, FL, United States
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11
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Decreased YAP activity reduces proliferative ability in human induced pluripotent stem cell of duchenne muscular dystrophy derived cardiomyocytes. Sci Rep 2021; 11:10351. [PMID: 33990626 PMCID: PMC8121946 DOI: 10.1038/s41598-021-89603-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2020] [Accepted: 04/20/2021] [Indexed: 11/29/2022] Open
Abstract
Duchenne muscular dystrophy (DMD) is characterized by progressive muscle degeneration accompanied by dilated cardiomyopathy. Recently, abnormality of yes-associated protein (YAP) has been reported as the pathogenesis of muscle degeneration of DMD; however YAP activity remains unclear in dystrophic heart of DMD. Herein, we investigated YAP activity using disease-specific induced pluripotent stem cell (iPSC) derived cardiomyocytes (CMs) in DMD. DMD-iPSCs were generated from DMD patient with exon 48–54 deletion in DMD, and genome-edited (Ed)-DMD-iPSCs with in-frame (Ed-DMD-iPSCs) were created using CRISPR/Cas9. Nuclear translocation of YAP [nuclear (N)/cytoplasmic (C) ratio] was significantly lower in DMD-iPSC-CMs than in Ed-DMD-iPSC-CMs. In addition, Ki67 expression, indicating proliferative ability, was significantly lower in DMD-iPSC-CMs than Ed-DMD-iPSC-CMs. Therefore, immunofluorescent staining showed that actin stress fibers associated with YAP activity by mechanotransduction were disorganized in DMD-iPSC-CMs. Lysophosphatidic acid (LPA), a known lipid mediator on induction of actin polymerization, significantly increased YAP activity and actin dynamics in DMD-iPSC-CMs using live cell imaging. These results suggested that altered YAP activity due to impaired actin dynamics reduced proliferative ability in DMD-iPSC-CMs. Hence, decreased YAP activity in dystrophic heart may contribute to DMD-cardiomyopathy pathogenesis.
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12
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Age-dependent changes in nuclear-cytoplasmic signaling in skeletal muscle. Exp Gerontol 2021; 150:111338. [PMID: 33862137 DOI: 10.1016/j.exger.2021.111338] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2021] [Revised: 03/28/2021] [Accepted: 04/03/2021] [Indexed: 02/07/2023]
Abstract
Mechanical forces are conducted through myofibers and into nuclei to regulate muscle development, hypertrophy, and homeostasis. We hypothesized that nuclei in aged muscle have changes in the nuclear envelope and associated proteins, resulting in altered markers of mechano-signaling. METHODS YAP/TAZ protein expression and gene expression of downstream targets, Ankrd1 and Cyr61, were evaluated as mechanotransduction indicators. Expression of proteins in the nuclear lamina and the nuclear pore complex (NPC) were assessed, and nuclear morphology was characterized by electron microscopy. Nuclear envelope permeability was assessed by uptake of 70 kDa fluorescent dextran. RESULTS Nuclear changes with aging included a relative decrease of lamin β1 and Nup107, and a relative increase in Nup93, which could underlie the aberrant nuclear morphology, increased nuclear leakiness, and elevated YAP/TAZ signaling. CONCLUSION Aged muscles have hyperactive nuclear-cytoplasmic signaling, indicative of altered nuclear mechanotransduction. These data highlight a possible role for the nucleus in aging-related aberrant mechano-sensing.
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Yatsenko AS, Kucherenko MM, Xie Y, Urlaub H, Shcherbata HR. Exocyst-mediated membrane trafficking of the lissencephaly-associated ECM receptor dystroglycan is required for proper brain compartmentalization. eLife 2021; 10:63868. [PMID: 33620318 PMCID: PMC7929561 DOI: 10.7554/elife.63868] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2020] [Accepted: 02/23/2021] [Indexed: 12/14/2022] Open
Abstract
To assemble a brain, differentiating neurons must make proper connections and establish specialized brain compartments. Abnormal levels of cell adhesion molecules disrupt these processes. Dystroglycan (Dg) is a major non-integrin cell adhesion receptor, deregulation of which is associated with dramatic neuroanatomical defects such as lissencephaly type II or cobblestone brain. The previously established Drosophila model for cobblestone lissencephaly was used to understand how Dg is regulated in the brain. During development, Dg has a spatiotemporally dynamic expression pattern, fine-tuning of which is crucial for accurate brain assembly. In addition, mass spectrometry analyses identified numerous components associated with Dg in neurons, including several proteins of the exocyst complex. Data show that exocyst-based membrane trafficking of Dg allows its distinct expression pattern, essential for proper brain morphogenesis. Further studies of the Dg neuronal interactome will allow identification of new factors involved in the development of dystroglycanopathies and advance disease diagnostics in humans.
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Affiliation(s)
- Andriy S Yatsenko
- Institute of Cell Biochemistry, Hannover Medical School, Hannover, Germany
| | - Mariya M Kucherenko
- Max Planck Research Group of Gene Expression and Signaling, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Yuanbin Xie
- Max Planck Research Group of Gene Expression and Signaling, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Henning Urlaub
- Bioanalytical Mass Spectrometry Research Group, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany.,University Medical Center Göttingen, Bioanalytics, Institute for Clinical Chemistry, Göttingen, Germany
| | - Halyna R Shcherbata
- Institute of Cell Biochemistry, Hannover Medical School, Hannover, Germany.,Max Planck Research Group of Gene Expression and Signaling, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
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Abstract
Skeletal muscle hypertrophy can be induced by hormones and growth factors acting directly as positive regulators of muscle growth or indirectly by neutralizing negative regulators, and by mechanical signals mediating the effect of resistance exercise. Muscle growth during hypertrophy is controlled at the translational level, through the stimulation of protein synthesis, and at the transcriptional level, through the activation of ribosomal RNAs and muscle-specific genes. mTORC1 has a central role in the regulation of both protein synthesis and ribosomal biogenesis. Several transcription factors and co-activators, including MEF2, SRF, PGC-1α4, and YAP promote the growth of the myofibers. Satellite cell proliferation and fusion is involved in some but not all muscle hypertrophy models.
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Affiliation(s)
| | - Carlo Reggiani
- Department of Biomedical Sciences, University of Padova, Italy
- Science and Research Centre Koper, Institute for Kinesiology Research, Koper, Slovenia
| | | | - Bert Blaauw
- Venetian Institute of Molecular Medicine, Padova, Italy
- Department of Biomedical Sciences, University of Padova, Italy
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15
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Kegelman CD, Collins JM, Nijsure MP, Eastburn EA, Boerckel JD. Gone Caving: Roles of the Transcriptional Regulators YAP and TAZ in Skeletal Development. Curr Osteoporos Rep 2020; 18:526-540. [PMID: 32712794 PMCID: PMC8040027 DOI: 10.1007/s11914-020-00605-3] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
PURPOSE OF REVIEW The development of the skeleton is controlled by cellular decisions determined by the coordinated activation of multiple transcription factors. Recent evidence suggests that the transcriptional regulator proteins, Yes-associated protein (YAP) and transcriptional co-activator with PDZ-binding motif (TAZ), could have important roles in directing the activity of these transcriptional programs. However, in vitro evidence for the roles of YAP and TAZ in skeletal cells has been hopelessly contradictory. The goals of this review are to provide a cross-sectional view on the state of the field and to synthesize the available data toward a unified perspective. RECENT FINDINGS YAP and TAZ are regulated by diverse upstream signals and interact downstream with multiple transcription factors involved in skeletal development, positioning YAP and TAZ as important signal integration nodes in an hourglass-shaped signaling pathway. Here, we provide a survey of putative transcriptional co-effectors for YAP and TAZ in skeletal cells. Synthesizing the in vitro data, we conclude that TAZ is consistently pro-osteogenic in function, while YAP can exhibit either pro- or anti-osteogenic activity depending on cell type and context. Synthesizing the in vivo data, we conclude that YAP and TAZ combinatorially promote developmental bone formation, bone matrix homeostasis, and endochondral fracture repair by regulating a variety of transcriptional programs depending on developmental stage. Here, we discuss the current understanding of the roles of the transcriptional regulators YAP and TAZ in skeletal development, and provide recommendations for continued study of molecular mechanisms, mechanotransduction, and therapeutic implications for skeletal disease.
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Affiliation(s)
- Christopher D Kegelman
- McKay Orthopaedic Research Laboratory, Department of Orthopaedic Surgery, University of Pennsylvania, 376A Stemmler Hall, Philadelphia, PA, USA
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, USA
| | - Joseph M Collins
- McKay Orthopaedic Research Laboratory, Department of Orthopaedic Surgery, University of Pennsylvania, 376A Stemmler Hall, Philadelphia, PA, USA
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, USA
| | - Madhura P Nijsure
- McKay Orthopaedic Research Laboratory, Department of Orthopaedic Surgery, University of Pennsylvania, 376A Stemmler Hall, Philadelphia, PA, USA
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, USA
| | - Emily A Eastburn
- McKay Orthopaedic Research Laboratory, Department of Orthopaedic Surgery, University of Pennsylvania, 376A Stemmler Hall, Philadelphia, PA, USA
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, USA
| | - Joel D Boerckel
- McKay Orthopaedic Research Laboratory, Department of Orthopaedic Surgery, University of Pennsylvania, 376A Stemmler Hall, Philadelphia, PA, USA.
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, USA.
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16
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Yatsenko AS, Kucherenko MM, Xie Y, Aweida D, Urlaub H, Scheibe RJ, Cohen S, Shcherbata HR. Profiling of the muscle-specific dystroglycan interactome reveals the role of Hippo signaling in muscular dystrophy and age-dependent muscle atrophy. BMC Med 2020; 18:8. [PMID: 31959160 PMCID: PMC6971923 DOI: 10.1186/s12916-019-1478-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/11/2019] [Accepted: 12/05/2019] [Indexed: 12/15/2022] Open
Abstract
BACKGROUND Dystroglycanopathies are a group of inherited disorders characterized by vast clinical and genetic heterogeneity and caused by abnormal functioning of the ECM receptor dystroglycan (Dg). Remarkably, among many cases of diagnosed dystroglycanopathies, only a small fraction can be linked directly to mutations in Dg or its regulatory enzymes, implying the involvement of other, not-yet-characterized, Dg-regulating factors. To advance disease diagnostics and develop new treatment strategies, new approaches to find dystroglycanopathy-related factors should be considered. The Dg complex is highly evolutionarily conserved; therefore, model genetic organisms provide excellent systems to address this challenge. In particular, Drosophila is amenable to experiments not feasible in any other system, allowing original insights about the functional interactors of the Dg complex. METHODS To identify new players contributing to dystroglycanopathies, we used Drosophila as a genetic muscular dystrophy model. Using mass spectrometry, we searched for muscle-specific Dg interactors. Next, in silico analyses allowed us to determine their association with diseases and pathological conditions in humans. Using immunohistochemical, biochemical, and genetic interaction approaches followed by the detailed analysis of the muscle tissue architecture, we verified Dg interaction with some of the discovered factors. Analyses of mouse muscles and myocytes were used to test if interactions are conserved in vertebrates. RESULTS The muscle-specific Dg complexome revealed novel components that influence the efficiency of Dg function in the muscles. We identified the closest human homologs for Dg-interacting partners, determined their significant enrichment in disease-associations, and verified some of the newly identified Dg interactions. We found that Dg associates with two components of the mechanosignaling Hippo pathway: the WW domain-containing proteins Kibra and Yorkie. Importantly, this conserved interaction manages adult muscle size and integrity. CONCLUSIONS The results presented in this study provide a new list of muscle-specific Dg interactors, further analysis of which could aid not only in the diagnosis of muscular dystrophies, but also in the development of new therapeutics. To regulate muscle fitness during aging and disease, Dg associates with Kibra and Yorkie and acts as a transmembrane Hippo signaling receptor that transmits extracellular information to intracellular signaling cascades, regulating muscle gene expression.
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Affiliation(s)
- Andriy S Yatsenko
- Gene Expression and Signaling Group, Institute of Cell Biochemistry, Hannover Medical School, Carl-Neuberg-Strasse 1, 30625, Hannover, Germany
| | - Mariya M Kucherenko
- Max Planck Research Group of Gene Expression and Signaling, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077, Göttingen, Germany.,Present Address: Department of Cardiothoracic and Vascular Surgery, German Heart Center Berlin, Augustenburger Platz 1, 13353, Berlin, Germany.,Institute of Physiology, Charité - University Medicine Berlin, Charitéplatz 1, 10117, Berlin, Germany
| | - Yuanbin Xie
- Max Planck Research Group of Gene Expression and Signaling, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077, Göttingen, Germany.,Present Address: University Medical Center, Centre for Anatomy, Institute of Neuroanatomy, Georg-August-University Göttingen, Kreuzbergring 36, 37075, Göttingen, Germany
| | - Dina Aweida
- Faculty of Biology, Technion, 32000, Haifa, Israel
| | - Henning Urlaub
- Bioanalytical Mass Spectrometry Research Group, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077, Göttingen, Germany.,Bioanalytics Institute for Clinical Chemistry, University Medical Center Goettingen, Robert Koch Strasse 40, 37075, Göttingen, Germany
| | - Renate J Scheibe
- Gene Expression and Signaling Group, Institute of Cell Biochemistry, Hannover Medical School, Carl-Neuberg-Strasse 1, 30625, Hannover, Germany
| | | | - Halyna R Shcherbata
- Gene Expression and Signaling Group, Institute of Cell Biochemistry, Hannover Medical School, Carl-Neuberg-Strasse 1, 30625, Hannover, Germany. .,Max Planck Research Group of Gene Expression and Signaling, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077, Göttingen, Germany.
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Flinn MA, Link BA, O'Meara CC. Upstream regulation of the Hippo-Yap pathway in cardiomyocyte regeneration. Semin Cell Dev Biol 2019; 100:11-19. [PMID: 31606277 DOI: 10.1016/j.semcdb.2019.09.004] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2019] [Revised: 08/27/2019] [Accepted: 09/11/2019] [Indexed: 12/17/2022]
Abstract
The response of the adult mammalian heart to injury such as myocardial infarction has long been described as primarily fibrotic scarring and adverse remodeling with little to no regeneration of cardiomyocytes. Emerging studies have challenged this paradigm by demonstrating that, indeed, adult mammalian cardiomyocytes are capable of completing cytokinesis albeit at levels vastly insufficient to compensate for the loss of functional cardiomyocytes following ischemic injury. Thus, there is great interest in identifying mechanisms to guide adult cardiomyocyte cell cycle re-entry and facilitate endogenous heart regeneration. The Hippo signaling pathway is a core kinase cascade that functions to suppress the transcriptional co-activators Yap and Taz by phosphorylation and therefore cytoplasmic retention or phospho-degradation. This pathway has recently sparked interest in the field of cardiac regeneration as inhibition of Hippo kinase signaling or overdriving the transcriptional co-activator, Yap, significantly promotes proliferation of terminally differentiated adult mammalian cardiomyocytes and can restore function in failing mouse hearts. Thus, the Hippo pathway is an attractive therapeutic target for promoting cardiomyocyte renewal and cardiac regeneration. Although the core kinases and transcriptional activators of the Hippo pathway have been studied extensively over the last twenty years, the regulatory inputs of this pathway, particularly in vertebrates, are poorly understood. Recent studies have elucidated several upstream regulatory inputs to the Hippo pathway in adult mammalian cardiomyocytes that influence cell proliferation and heart regeneration. Considering upstream inputs to the Hippo pathway are thought to be context and cell type specific, targeting these various components could serve as a therapeutic approach for refining Hippo-Yap signaling in the heart. Here, we provide an overview of the emerging regulatory inputs to the Hippo pathway as they relate to mammalian cardiomyocytes and heart regeneration.
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Affiliation(s)
- Michael A Flinn
- Department of Physiology, Medical College of Wisconsin, Milwaukee, WI, USA; Cardiovascular Center, Medical College of Wisconsin, Milwaukee, WI, USA
| | - Brian A Link
- Department of Cell Biology, Neurobiology, and Anatomy, Medical College of Wisconsin, Milwaukee, WI, USA; Cardiovascular Center, Medical College of Wisconsin, Milwaukee, WI, USA
| | - Caitlin C O'Meara
- Department of Physiology, Medical College of Wisconsin, Milwaukee, WI, USA; Cardiovascular Center, Medical College of Wisconsin, Milwaukee, WI, USA; Genomics Sciences and Precision Medicine Center, Medical College of Wisconsin, Milwaukee, WI, USA.
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Boppart MD, Mahmassani ZS. Integrin signaling: linking mechanical stimulation to skeletal muscle hypertrophy. Am J Physiol Cell Physiol 2019; 317:C629-C641. [PMID: 31314586 DOI: 10.1152/ajpcell.00009.2019] [Citation(s) in RCA: 71] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The α7β1-integrin is a transmembrane adhesion protein that connects laminin in the extracellular matrix (ECM) with actin in skeletal muscle fibers. The α7β1-integrin is highly expressed in skeletal muscle and is concentrated at costameres and myotendious junctions, providing the opportunity to transmit longitudinal and lateral forces across the membrane. Studies have demonstrated that α7-integrin subunit mRNA and protein are upregulated following eccentric contractions as a mechanism to reinforce load-bearing structures and resist injury with repeated bouts of exercise. It has been hypothesized for many years that the integrin can also promote protein turnover in a manner that can promote beneficial adaptations with resistance exercise training, including hypertrophy. This review provides basic information about integrin structure and activation and then explores its potential to serve as a critical mechanosensor and activator of muscle protein synthesis and growth. Overall, the hypothesis is proposed that the α7β1-integrin can contribute to mechanical-load induced skeletal muscle growth via an mammalian target of rapamycin complex 1-independent mechanism.
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Affiliation(s)
- Marni D Boppart
- Department of Kinesiology and Community Health, University of Illinois at Urbana-Champaign, Urbana, Illinois.,Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois
| | - Ziad S Mahmassani
- Department of Physical Therapy and Athletic Training, University of Utah, Salt Lake City, Utah
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