1
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Lei L, Wen Z, Cao M, Zhang H, Ling SKK, Fu BSC, Qin L, Xu J, Yung PSH. The emerging role of Piezo1 in the musculoskeletal system and disease. Theranostics 2024; 14:3963-3983. [PMID: 38994033 PMCID: PMC11234281 DOI: 10.7150/thno.96959] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2024] [Accepted: 05/15/2024] [Indexed: 07/13/2024] Open
Abstract
Piezo1, a mechanosensitive ion channel, has emerged as a key player in translating mechanical stimuli into biological signaling. Its involvement extends beyond physiological and pathological processes such as lymphatic vessel development, axon growth, vascular development, immunoregulation, and blood pressure regulation. The musculoskeletal system, responsible for structural support, movement, and homeostasis, has recently attracted attention regarding the significance of Piezo1. This review aims to provide a comprehensive summary of the current research on Piezo1 in the musculoskeletal system, highlighting its impact on bone formation, myogenesis, chondrogenesis, intervertebral disc homeostasis, tendon matrix cross-linking, and physical activity. Additionally, we explore the potential of targeting Piezo1 as a therapeutic approach for musculoskeletal disorders, including osteoporosis, muscle atrophy, intervertebral disc degeneration, and osteoarthritis.
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Affiliation(s)
- Lei Lei
- Musculoskeletal Research Laboratory and Centre of Musculoskeletal Aging and Regeneration, Department of Orthopaedics and Traumatology, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong SAR, China
| | - Zhenkang Wen
- Musculoskeletal Research Laboratory and Centre of Musculoskeletal Aging and Regeneration, Department of Orthopaedics and Traumatology, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong SAR, China
| | - Mingde Cao
- Musculoskeletal Research Laboratory and Centre of Musculoskeletal Aging and Regeneration, Department of Orthopaedics and Traumatology, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong SAR, China
| | - Haozhi Zhang
- Musculoskeletal Research Laboratory and Centre of Musculoskeletal Aging and Regeneration, Department of Orthopaedics and Traumatology, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong SAR, China
| | - Samuel Ka-Kin Ling
- Musculoskeletal Research Laboratory and Centre of Musculoskeletal Aging and Regeneration, Department of Orthopaedics and Traumatology, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong SAR, China
| | - Bruma Sai-Chuen Fu
- Musculoskeletal Research Laboratory and Centre of Musculoskeletal Aging and Regeneration, Department of Orthopaedics and Traumatology, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong SAR, China
| | - Ling Qin
- Musculoskeletal Research Laboratory and Centre of Musculoskeletal Aging and Regeneration, Department of Orthopaedics and Traumatology, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong SAR, China
- The Sir Yue-Kong Pao Cancer Centre, Prince of Wales Hospital, The Chinese University of Hong Kong, Hong Kong SAR, China
- Joint Laboratory of Chinese Academic of Science and Hong Kong for Biomaterials, The Chinese University of Hong Kong, Hong Kong SAR, China
| | - Jiankun Xu
- Musculoskeletal Research Laboratory and Centre of Musculoskeletal Aging and Regeneration, Department of Orthopaedics and Traumatology, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong SAR, China
- The Sir Yue-Kong Pao Cancer Centre, Prince of Wales Hospital, The Chinese University of Hong Kong, Hong Kong SAR, China
- Joint Laboratory of Chinese Academic of Science and Hong Kong for Biomaterials, The Chinese University of Hong Kong, Hong Kong SAR, China
| | - Patrick Shu-Hang Yung
- Musculoskeletal Research Laboratory and Centre of Musculoskeletal Aging and Regeneration, Department of Orthopaedics and Traumatology, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong SAR, China
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2
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Mechanotransduction for Muscle Protein Synthesis via Mechanically Activated Ion Channels. Life (Basel) 2023; 13:life13020341. [PMID: 36836698 PMCID: PMC9962945 DOI: 10.3390/life13020341] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2023] [Revised: 01/24/2023] [Accepted: 01/26/2023] [Indexed: 02/03/2023] Open
Abstract
Cell mechanotransduction, the ability to detect physical forces and convert them into a series of biochemical events, is important for a wide range of physiological processes. Cells express an array of mechanosensors transducing physical forces into intracellular signaling cascades, including ion channels. Ion channels that can be directly activated by mechanical cues are known as mechanically activated (MA), or stretch-activated (SA), channels. In response to repeated exposures to mechanical stimulation in the form of resistance training, enhanced protein synthesis and fiber hypertrophy are elicited in skeletal muscle, whereas a lack of mechanical stimuli due to inactivity/mechanical unloading leads to reduced muscle protein synthesis and fiber atrophy. To date, the role of MA channels in the transduction of mechanical load to intracellular signaling pathways regulating muscle protein synthesis is poorly described. This review article will discuss MA channels in striated muscle, their regulation, and putative roles in the anabolic processes in muscle cells/fibers in response to mechanical stimuli.
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3
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Bernareggi A, Bosutti A, Massaria G, Giniatullin R, Malm T, Sciancalepore M, Lorenzon P. The State of the Art of Piezo1 Channels in Skeletal Muscle Regeneration. Int J Mol Sci 2022; 23:ijms23126616. [PMID: 35743058 PMCID: PMC9224226 DOI: 10.3390/ijms23126616] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2022] [Revised: 06/10/2022] [Accepted: 06/11/2022] [Indexed: 02/07/2023] Open
Abstract
Piezo1 channels are highly mechanically-activated cation channels that can sense and transduce the mechanical stimuli into physiological signals in different tissues including skeletal muscle. In this focused review, we summarize the emerging evidence of Piezo1 channel-mediated effects in the physiology of skeletal muscle, with a particular focus on the role of Piezo1 in controlling myogenic precursor activity and skeletal muscle regeneration and vascularization. The disclosed effects reported by pharmacological activation of Piezo1 channels with the selective agonist Yoda1 indicate a potential impact of Piezo1 channel activity in skeletal muscle regeneration, which is disrupted in various muscular pathological states. All findings reported so far agree with the idea that Piezo1 channels represent a novel, powerful molecular target to develop new therapeutic strategies for preventing or ameliorating skeletal muscle disorders characterized by an impairment of tissue regenerative potential.
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Affiliation(s)
- Annalisa Bernareggi
- Department of Life Sciences, University of Trieste, 34127 Trieste, Italy; (A.B.); (G.M.); (M.S.); (P.L.)
- Correspondence:
| | - Alessandra Bosutti
- Department of Life Sciences, University of Trieste, 34127 Trieste, Italy; (A.B.); (G.M.); (M.S.); (P.L.)
| | - Gabriele Massaria
- Department of Life Sciences, University of Trieste, 34127 Trieste, Italy; (A.B.); (G.M.); (M.S.); (P.L.)
| | - Rashid Giniatullin
- A.I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, 70211 Kuopio, Finland; (R.G.); (T.M.)
| | - Tarja Malm
- A.I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, 70211 Kuopio, Finland; (R.G.); (T.M.)
| | - Marina Sciancalepore
- Department of Life Sciences, University of Trieste, 34127 Trieste, Italy; (A.B.); (G.M.); (M.S.); (P.L.)
| | - Paola Lorenzon
- Department of Life Sciences, University of Trieste, 34127 Trieste, Italy; (A.B.); (G.M.); (M.S.); (P.L.)
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4
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Gong Y, Laheji F, Berenson A, Qian A, Park SO, Kok R, Selig M, Hahn R, Sadjadi R, Kemp S, Eichler F. Peroxisome Metabolism Contributes to PIEZO2-Mediated Mechanical Allodynia. Cells 2022; 11:1842. [PMID: 35681537 PMCID: PMC9180358 DOI: 10.3390/cells11111842] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2022] [Revised: 05/21/2022] [Accepted: 06/01/2022] [Indexed: 11/17/2022] Open
Abstract
Mutations in the peroxisomal half-transporter ABCD1 cause X-linked adrenoleukodystrophy, resulting in elevated very long-chain fatty acids (VLCFA), progressive neurodegeneration and an associated pain syndrome that is poorly understood. In the nervous system of mice, we found ABCD1 expression to be highest in dorsal root ganglia (DRG), with satellite glial cells (SGCs) displaying higher expression than neurons. We subsequently examined sensory behavior and DRG pathophysiology in mice deficient in ABCD1 compared to wild-type mice. Beginning at 8 months of age, Abcd1-/y mice developed persistent mechanical allodynia. DRG had a greater number of IB4-positive nociceptive neurons expressing PIEZO2, the mechanosensitive ion channel. Blocking PIEZO2 partially rescued the mechanical allodynia. Beyond affecting neurons, ABCD1 deficiency impacted SGCs, as demonstrated by high levels of VLCFA, increased glial fibrillary acidic protein (GFAP), as well as genes disrupting neuron-SGC connectivity. These findings suggest that lack of the peroxisomal half-transporter ABCD1 leads to PIEZO2-mediated mechanical allodynia as well as SGC dysfunction. Given the known supportive role of SGCs to neurons, this elucidates a novel mechanism underlying pain in X-linked adrenoleukodystrophy.
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Affiliation(s)
- Yi Gong
- Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA; (Y.G.); (F.L.); (A.B.); (A.Q.); (S.-O.P.); (M.S.); (R.H.); (R.S.)
| | - Fiza Laheji
- Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA; (Y.G.); (F.L.); (A.B.); (A.Q.); (S.-O.P.); (M.S.); (R.H.); (R.S.)
| | - Anna Berenson
- Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA; (Y.G.); (F.L.); (A.B.); (A.Q.); (S.-O.P.); (M.S.); (R.H.); (R.S.)
| | - April Qian
- Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA; (Y.G.); (F.L.); (A.B.); (A.Q.); (S.-O.P.); (M.S.); (R.H.); (R.S.)
| | - Sang-O Park
- Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA; (Y.G.); (F.L.); (A.B.); (A.Q.); (S.-O.P.); (M.S.); (R.H.); (R.S.)
| | - Rene Kok
- Laboratory Genetic Metabolic Diseases, Department of Clinical Chemistry, Amsterdam University Medical Center, Amsterdam Gastroenterology Endocrinology Metabolism, University of Amsterdam, 1105 Amsterdam, The Netherlands; (R.K.); (S.K.)
| | - Martin Selig
- Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA; (Y.G.); (F.L.); (A.B.); (A.Q.); (S.-O.P.); (M.S.); (R.H.); (R.S.)
| | - Ryan Hahn
- Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA; (Y.G.); (F.L.); (A.B.); (A.Q.); (S.-O.P.); (M.S.); (R.H.); (R.S.)
| | - Reza Sadjadi
- Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA; (Y.G.); (F.L.); (A.B.); (A.Q.); (S.-O.P.); (M.S.); (R.H.); (R.S.)
| | - Stephan Kemp
- Laboratory Genetic Metabolic Diseases, Department of Clinical Chemistry, Amsterdam University Medical Center, Amsterdam Gastroenterology Endocrinology Metabolism, University of Amsterdam, 1105 Amsterdam, The Netherlands; (R.K.); (S.K.)
- Department of Pediatric Neurology, Emma Children’s Hospital, Amsterdam University Medical Center, Amsterdam Neuroscience, University of Amsterdam, 1105 Amsterdam, The Netherlands
| | - Florian Eichler
- Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA; (Y.G.); (F.L.); (A.B.); (A.Q.); (S.-O.P.); (M.S.); (R.H.); (R.S.)
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5
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Lachowski D, Matellan C, Gopal S, Cortes E, Robinson BK, Saiani A, Miller AF, Stevens MM, del Río Hernández AE. Substrate Stiffness-Driven Membrane Tension Modulates Vesicular Trafficking via Caveolin-1. ACS NANO 2022; 16:4322-4337. [PMID: 35255206 PMCID: PMC9007531 DOI: 10.1021/acsnano.1c10534] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
Liver fibrosis, a condition characterized by extensive deposition and cross-linking of extracellular matrix (ECM) proteins, is idiosyncratic in cases of chronic liver injury. The dysregulation of ECM remodeling by hepatic stellate cells (HSCs), the main mediators of fibrosis, results in an elevated ECM stiffness that drives the development of chronic liver disease such as cirrhosis and hepatocellular carcinoma. Tissue inhibitor of matrix metalloproteinase-1 (TIMP-1) is a key element in the regulation of ECM remodeling, which modulates the degradation and turnover of ECM components. We have previously reported that a rigid, fibrotic-like substrate can impact TIMP-1 expression at the protein level in HSCs without altering its mRNA expression. While HSCs are known to be highly susceptible to mechanical stimuli, the mechanisms through which mechanical cues regulate TIMP-1 at the post-translational level remain unclear. Here, we show a mechanism of regulation of plasma membrane tension by matrix stiffness. We found that this effect is orchestrated by the β1 integrin/RhoA axis and results in elevated exocytosis and secretion of TIMP-1 in a caveolin-1- and dynamin-2-dependent manner. We then show that TIMP-1 and caveolin-1 expression increases in cirrhosis and hepatocellular carcinoma. These conditions are associated with fibrosis, and this effect can be recapitulated in 3D fibrosis models consisting of hepatic stellate cells encapsulated in a self-assembling polypeptide hydrogel. This work positions stiffness-dependent membrane tension as a key regulator of enzyme secretion and function and a potential target for therapeutic strategies that aim at modulating ECM remodeling in chronic liver disease.
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Affiliation(s)
- Dariusz Lachowski
- Cellular
and Molecular Biomechanics Laboratory, Department of Bioengineering, Imperial College London, London SW7 2AZ, United Kingdom
- Manchester
BIOGEL, Mereside, Alderley Park, Alderley Edge, Cheshire SK10 4TG, United Kingdom
| | - Carlos Matellan
- Cellular
and Molecular Biomechanics Laboratory, Department of Bioengineering, Imperial College London, London SW7 2AZ, United Kingdom
| | - Sahana Gopal
- Department
of Materials, Department of Bioengineering and Institute of Biomedical
Engineering, Imperial College London, London SW7 2AZ, United Kingdom
| | - Ernesto Cortes
- Cellular
and Molecular Biomechanics Laboratory, Department of Bioengineering, Imperial College London, London SW7 2AZ, United Kingdom
| | - Benjamin K. Robinson
- Cellular
and Molecular Biomechanics Laboratory, Department of Bioengineering, Imperial College London, London SW7 2AZ, United Kingdom
| | - Alberto Saiani
- Department
of Materials and Manchester Institute of Biotechnology, Faculty of
Science and Engineering, The University
of Manchester, Oxford Road, Manchester M13 9PL, United Kingdom
- Manchester
BIOGEL, Mereside, Alderley Park, Alderley Edge, Cheshire SK10 4TG, United Kingdom
| | - Aline F. Miller
- Department
of Chemical Engineering and Manchester Institute of Biotechnology,
Faculty of Science and Engineering, The
University of Manchester, Oxford Road, Manchester M13 9PL, United Kingdom
- Manchester
BIOGEL, Mereside, Alderley Park, Alderley Edge, Cheshire SK10 4TG, United Kingdom
| | - Molly M. Stevens
- Department
of Materials, Department of Bioengineering and Institute of Biomedical
Engineering, Imperial College London, London SW7 2AZ, United Kingdom
| | - Armando E. del Río Hernández
- Cellular
and Molecular Biomechanics Laboratory, Department of Bioengineering, Imperial College London, London SW7 2AZ, United Kingdom
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6
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Luo M, Cai G, Ho KKY, Wen K, Tong Z, Deng L, Liu AP. Compression enhances invasive phenotype and matrix degradation of breast Cancer cells via Piezo1 activation. BMC Mol Cell Biol 2022; 23:1. [PMID: 34979904 PMCID: PMC8722159 DOI: 10.1186/s12860-021-00401-6] [Citation(s) in RCA: 35] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2021] [Accepted: 12/17/2021] [Indexed: 12/14/2022] Open
Abstract
Background Uncontrolled growth in solid breast cancer generates mechanical compression that may drive the cancer cells into a more invasive phenotype, but little is known about how such compression affects the key events and corresponding regulatory mechanisms associated with invasion of breast cancer cells including cellular behaviors and matrix degradation. Results Here we show that compression enhanced invasion and matrix degradation of breast cancer cells. We also identified Piezo1 as the putative mechanosensitive cellular component that transmitted compression to not only enhance the invasive phenotype, but also induce calcium influx and downstream Src signaling. Furthermore, we demonstrated that Piezo1 was mainly localized in caveolae, and both Piezo1 expression and compression-enhanced invasive phenotype of the breast cancer cells were reduced when caveolar integrity was compromised by either knocking down caveolin1 expression or depleting cholesterol content. Conclusions Taken together, our data indicate that mechanical compression activates Piezo1 channels to mediate enhanced breast cancer cell invasion, which involves both cellular events and matrix degradation. This may be a critical mechanotransduction pathway during breast cancer metastasis, and thus potentially a novel therapeutic target for the disease. Supplementary Information The online version contains supplementary material available at 10.1186/s12860-021-00401-6.
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Affiliation(s)
- Mingzhi Luo
- Institute of Biomedical Engineering and Health Sciences, Changzhou University, Changzhou, Jiangsu, People's Republic of China.,Department of Mechanical Engineering, University of Michigan, Ann Arbor, MI, USA
| | - Grace Cai
- Applied Physics Program, University of Michigan, Ann Arbor, MI, USA
| | - Kenneth K Y Ho
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, MI, USA.,Present address: Center for Molecular Imaging, Department of Radiology, University of Michigan, Ann Arbor, MI, USA
| | - Kang Wen
- Institute of Biomedical Engineering and Health Sciences, Changzhou University, Changzhou, Jiangsu, People's Republic of China
| | - Zhaowen Tong
- Applied Physics Program, University of Michigan, Ann Arbor, MI, USA
| | - Linhong Deng
- Institute of Biomedical Engineering and Health Sciences, Changzhou University, Changzhou, Jiangsu, People's Republic of China.
| | - Allen P Liu
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, MI, USA. .,Applied Physics Program, University of Michigan, Ann Arbor, MI, USA. .,Department of Biophysics, University of Michigan, Ann Arbor, MI, USA. .,Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, USA. .,Cellular and Molecular Biology Program, University of Michigan, Ann Arbor, MI, USA.
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7
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Dudãu M, Codrici E, Tanase C, Gherghiceanu M, Enciu AM, Hinescu ME. Caveolae as Potential Hijackable Gates in Cell Communication. Front Cell Dev Biol 2020; 8:581732. [PMID: 33195223 PMCID: PMC7652756 DOI: 10.3389/fcell.2020.581732] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Accepted: 10/08/2020] [Indexed: 12/16/2022] Open
Abstract
Caveolae are membrane microdomains described in many cell types involved in endocytocis, transcytosis, cell signaling, mechanotransduction, and aging. They are found at the interface with the extracellular environment and are structured by caveolin and cavin proteins. Caveolae and caveolins mediate transduction of chemical messages via signaling pathways, as well as non-chemical messages, such as stretching or shear stress. Various pathogens or signals can hijack these gates, leading to infectious, oncogenic and even caveolin-related diseases named caveolinopathies. By contrast, preclinical and clinical research have fallen behind in their attempts to hijack caveolae and caveolins for therapeutic purposes. Caveolae involvement in human disease is not yet fully explored or understood and, of all their scaffold proteins, only caveolin-1 is being considered in clinical trials as a possible biomarker of disease. This review briefly summarizes current knowledge about caveolae cell signaling and raises the hypothesis whether these microdomains could serve as hijackable “gatekeepers” or “gateways” in cell communication. Furthermore, because cell signaling is one of the most dynamic domains in translating data from basic to clinical research, we pay special attention to translation of caveolae, caveolin, and cavin research into clinical practice.
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Affiliation(s)
- Maria Dudãu
- Biochemistry-Proteomics Laboratory, Victor Babes National Institute of Pathology, Bucharest, Romania.,Cell Biology and Histology Department, Carol Davila University of Medicine and Pharmacy, Bucharest, Romania
| | - Elena Codrici
- Biochemistry-Proteomics Laboratory, Victor Babes National Institute of Pathology, Bucharest, Romania
| | - Cristiana Tanase
- Biochemistry-Proteomics Laboratory, Victor Babes National Institute of Pathology, Bucharest, Romania.,Clinical Biochemistry Department, Faculty of Medicine, Titu Maiorescu University, Bucharest, Romania
| | - Mihaela Gherghiceanu
- Biochemistry-Proteomics Laboratory, Victor Babes National Institute of Pathology, Bucharest, Romania.,Cell Biology and Histology Department, Carol Davila University of Medicine and Pharmacy, Bucharest, Romania
| | - Ana-Maria Enciu
- Biochemistry-Proteomics Laboratory, Victor Babes National Institute of Pathology, Bucharest, Romania.,Cell Biology and Histology Department, Carol Davila University of Medicine and Pharmacy, Bucharest, Romania
| | - Mihail E Hinescu
- Biochemistry-Proteomics Laboratory, Victor Babes National Institute of Pathology, Bucharest, Romania.,Cell Biology and Histology Department, Carol Davila University of Medicine and Pharmacy, Bucharest, Romania
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8
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Roos A, Hathazi D, Schara U. Immunofluorescence-Based Analysis of Caveolin-3 in the Diagnostic Management of Neuromuscular Diseases. Methods Mol Biol 2020; 2169:197-216. [PMID: 32548831 DOI: 10.1007/978-1-0716-0732-9_18] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Immunohistochemistry- and/or immunofluorescence-based analysis of muscular proteins represents a standard procedure in the diagnostic management of patients suffering from neuromuscular diseases such as "Caveolinopathies" which are caused by mutations in the CAV3 gene encoding for caveolin-3. Human caveolin-3 is a 151 amino acid sized transmembrane protein localized within caveolae, predominantly expressed in cardiac and skeletal muscle cells and involved in a diversity of cellular functions crucial for muscle cell homeostasis. Loss of caveolin-3 protein abundance is indicative for the presence of pathogenic mutations within the corresponding gene and thus for the diagnosis of "Caveolinopathies." Moreover, description of abnormal immunoreactivity findings for the caveolin-3 protein is increasing in the context of other neuromuscular diseases suggesting that profound knowledge of abnormal caveolin-3-expression and/or distribution findings can be decisive also for the diagnosis of other neurological diseases as well as for a better understanding of the biology of the protein. Here, we summarize the current knowledge about the caveolin-3, report on a protocol for immunofluorescence-based analysis of the protein in the diagnostic workup of neuromuscular patients-also considering problems encountered-and confirm as well as summarize already published abnormal histological findings in muscular pathologies beyond "Caveolinopathies."
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Affiliation(s)
- Andreas Roos
- Department of Neuropediatrics, Developmental Neurology and Social Pediatrics, Centre for Neuromuscular Disorders in Children, University Hospital Essen, University of Duisburg-Essen, Essen, Germany.
| | - Denisa Hathazi
- Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK
| | - Ulrike Schara
- Department of Neuropediatrics, Developmental Neurology and Social Pediatrics, Centre for Neuromuscular Disorders in Children, University Hospital Essen, University of Duisburg-Essen, Essen, Germany
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9
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Hinze C, Boucrot E. Endocytosis in proliferating, quiescent and terminally differentiated cells. J Cell Sci 2018; 131:131/23/jcs216804. [PMID: 30504135 DOI: 10.1242/jcs.216804] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Endocytosis mediates nutrient uptake, receptor internalization and the regulation of cell signaling. It is also hijacked by many bacteria, viruses and toxins to mediate their cellular entry. Several endocytic routes exist in parallel, fulfilling different functions. Most studies on endocytosis have used transformed cells in culture. However, as the majority of cells in an adult body have exited the cell cycle, our understanding is biased towards proliferating cells. Here, we review the evidence for the different pathways of endocytosis not only in dividing, but also in quiescent, senescent and terminally differentiated cells. During mitosis, residual endocytosis is dedicated to the internalization of caveolae and specific receptors. In non-dividing cells, clathrin-mediated endocytosis (CME) functions, but the activity of alternative processes, such as caveolae, macropinocytosis and clathrin-independent routes, vary widely depending on cell types and functions. Endocytosis supports the quiescent state by either upregulating cell cycle arrest pathways or downregulating mitogen-induced signaling, thereby inhibiting cell proliferation. Endocytosis in terminally differentiated cells, such as skeletal muscles, adipocytes, kidney podocytes and neurons, supports tissue-specific functions. Finally, uptake is downregulated in senescent cells, making them insensitive to proliferative stimuli by growth factors. Future studies should reveal the molecular basis for the differences in activities between the different cell states.
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Affiliation(s)
- Claudia Hinze
- Institute of Structural and Molecular Biology, Division of Biosciences, University College London, London WC1E 6BT, UK
| | - Emmanuel Boucrot
- Institute of Structural and Molecular Biology, Division of Biosciences, University College London, London WC1E 6BT, UK .,Institute of Structural and Molecular Biology, Department of Biological Sciences, Birkbeck College, London WC1E 7HX, UK
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10
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Morris CE. Cytotoxic Swelling of Sick Excitable Cells - Impaired Ion Homeostasis and Membrane Tension Homeostasis in Muscle and Neuron. CURRENT TOPICS IN MEMBRANES 2018; 81:457-496. [PMID: 30243439 DOI: 10.1016/bs.ctm.2018.06.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
When they become simultaneously leaky to both Na+ and Cl-, excitable cells are vulnerable to potentially lethal cytotoxic swelling. Swelling ensues in spite of an isosmotic milieu because the entering ions add osmolytes to the cytoplasm's high concentration of impermeant anionic osmolytes. An influx of osmotically-obliged water is unavoidable. A cell that cannot stanch at least one the leaks will succumb to death by Donnan effect. "Sick excitable cells" are those injured through ischemia, trauma, inflammation, hyperactivity, genetically-impaired membrane skeletons and other insults, all of which foster bleb-damage to regions of the plasma membrane. Nav channels resident in damaged membrane exhibit left-shifted kinetics; the corresponding Nav window conductance constitutes a Na+-leak. In cortical neurons, sustained depolarization to ∼-20mV elicits a sustained lethal gCl. Underlying Vrest in skeletal muscle is a constitutively active gCl; not surprisingly therefore, dystrophic muscle fibers, which are prone to bleb damage and which exhibit Nav-leak and Na+-overload, are prone to cytotoxic swelling. To restore viability in cytotoxically swelling neurons and muscle, the imperative of fully functional ion homeostasis is well-recognized. However, as emphasized here, in a healthy excitable cell, fully functional membrane tension homeostasis is also imperative. ATPase-pumps keep plasma membrane batteries charged, and ATPase-motor proteins maintain membrane tone. In sick excitable cells, neither condition prevails.
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Affiliation(s)
- Catherine E Morris
- Senior Scientist Emeritus, Neuroscience, Ottawa Hospital Research Institute, Ottawa, ON, Canada
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11
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Electrophysiological experiments in microgravity: lessons learned and future challenges. NPJ Microgravity 2018; 4:7. [PMID: 29619409 PMCID: PMC5876337 DOI: 10.1038/s41526-018-0042-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2017] [Revised: 03/07/2018] [Accepted: 03/07/2018] [Indexed: 02/08/2023] Open
Abstract
Advances in electrophysiological experiments have led to the discovery of mechanosensitive ion channels (MSCs) and the identification of the physiological function of specific MSCs. They are believed to play important roles in mechanosensitive pathways by allowing for cells to sense their mechanical environment. However, the physiological function of many MSCs has not been conclusively identified. Therefore, experiments have been developed that expose cells to various mechanical loads, such as shear flow, membrane indentation, osmotic challenges and hydrostatic pressure. In line with these experiments, mechanical unloading, as experienced in microgravity, represents an interesting alternative condition, since exposure to microgravity leads to a series of physiological adaption processes. As outlined in this review, electrophysiological experiments performed in microgravity have shown an influence of gravity on biological functions depending on ion channels at all hierarchical levels, from the cellular level to organs. In this context, calcium signaling represents an interesting cellular pathway, as it involves the direct action of calcium-permeable ion channels, and specific gravitatic cells have linked graviperception to this pathway. Multiple key proteins in the graviperception pathways have been identified. However, measurements on vertebrae cells have revealed controversial results. In conclusion, electrophysiological experiments in microgravity have shown that ion-channel-dependent physiological processes are altered in mechanically unloaded conditions. Future experiments may provide a better understanding of the underlying mechanisms.
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Adding dimension to cellular mechanotransduction: Advances in biomedical engineering of multiaxial cell-stretch systems and their application to cardiovascular biomechanics and mechano-signaling. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2017. [DOI: 10.1016/j.pbiomolbio.2017.06.011] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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Suchyna TM. Piezo channels and GsMTx4: Two milestones in our understanding of excitatory mechanosensitive channels and their role in pathology. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2017; 130:244-253. [PMID: 28778608 DOI: 10.1016/j.pbiomolbio.2017.07.011] [Citation(s) in RCA: 55] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/21/2017] [Revised: 07/17/2017] [Accepted: 07/21/2017] [Indexed: 12/19/2022]
Abstract
Discovery of Piezo channels and the reporting of their sensitivity to the inhibitor GsMTx4 were important milestones in the study of non-selective cationic mechanosensitive channels (MSCs) in normal physiology and pathogenesis. GsMTx4 had been used for years to investigate the functional role of cationic MSCs, especially in muscle tissue, but with little understanding of its target or inhibitory mechanism. The sensitivity of Piezo channels to bilayer stress and its robust mechanosensitivity when expressed in heterologous systems were keys to determining GsMTx4's mechanism of action. However, questions remain regarding Piezo's role in muscle function due to the non-selective nature of GsMTx4 inhibition toward membrane mechanoenzymes and the implication of MCS channel types by genetic knockdown. Evidence supporting Piezo like activity, at least in the developmental stages of muscle, is presented. While the MSC targets of GsMTx4 in muscle pathology are unclear, its muscle protective effects are clearly demonstrated in two recent in situ studies on normal cardiomyocytes and dystrophic skeletal muscle. The muscle protective function may be due to the combined effect of GsMTx4's inhibitory action on cationic MSCs like Piezo and TRP, and its potentiation of repolarizing K+ selective MSCs like K2P and SAKCa. Paradoxically, the potent in vitro action of GsMTx4 on many physiological functions seems to conflict with its lack of in situ side-effects on normal animal physiology. Future investigations into cytoskeletal control of sarcolemma mechanics and the suspected inclusion of MSCs in membrane micro/nano sized domains with distinct mechanical properties will aide our understanding of this dichotomy.
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Affiliation(s)
- Thomas M Suchyna
- University of Buffalo, Dept. of Physiology and Biophysics, Buffalo, NY, USA.
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Hissa B, Oakes PW, Pontes B, Ramírez-San Juan G, Gardel ML. Cholesterol depletion impairs contractile machinery in neonatal rat cardiomyocytes. Sci Rep 2017; 7:43764. [PMID: 28256617 PMCID: PMC5335656 DOI: 10.1038/srep43764] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2016] [Accepted: 01/27/2017] [Indexed: 02/06/2023] Open
Abstract
Cholesterol regulates numerous cellular processes. Depleting its synthesis in skeletal myofibers induces vacuolization and contraction impairment. However, little is known about how cholesterol reduction affects cardiomyocyte behavior. Here, we deplete cholesterol by incubating neonatal cardiomyocytes with methyl-beta-cyclodextrin. Traction force microscopy shows that lowering cholesterol increases the rate of cell contraction and generates defects in cell relaxation. Cholesterol depletion also increases membrane tension, Ca2+ spikes frequency and intracellular Ca2+ concentration. These changes can be correlated with modifications in caveolin-3 and L-Type Ca2+ channel distributions across the sarcolemma. Channel regulation is also compromised since cAMP-dependent PKA activity is enhanced, increasing the probability of L-Type Ca2+ channel opening events. Immunofluorescence reveals that cholesterol depletion abrogates sarcomeric organization, changing spacing and alignment of α-actinin bands due to increase in proteolytic activity of calpain. We propose a mechanism in which cholesterol depletion triggers a signaling cascade, culminating with contraction impairment and myofibril disruption in cardiomyocytes.
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Affiliation(s)
- Barbara Hissa
- James Franck Institute, Institute for Biophysical Dynamics and Physics Department, University of Chicago, Chicago, IL, United States
| | - Patrick W. Oakes
- James Franck Institute, Institute for Biophysical Dynamics and Physics Department, University of Chicago, Chicago, IL, United States
| | - Bruno Pontes
- LPO-COPEA, Instituto de Ciências Biomédicas, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil
| | - Guillermina Ramírez-San Juan
- James Franck Institute, Institute for Biophysical Dynamics and Physics Department, University of Chicago, Chicago, IL, United States
| | - Margaret L. Gardel
- James Franck Institute, Institute for Biophysical Dynamics and Physics Department, University of Chicago, Chicago, IL, United States
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Gnanasambandam R, Gottlieb PA, Sachs F. The Kinetics and the Permeation Properties of Piezo Channels. CURRENT TOPICS IN MEMBRANES 2017; 79:275-307. [PMID: 28728821 DOI: 10.1016/bs.ctm.2016.11.004] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Piezo channels are eukaryotic, cation-selective mechanosensitive channels (MSCs), which show rapid activation and voltage-dependent inactivation. The kinetics of these channels are largely consistent across multiple cell types and different stimulation paradigms with some minor variability. No accessory subunits that associate with Piezo channels have been reported. They are homotrimers and each ∼300kD monomer has an N-terminal propeller blade-like mechanosensing module, which can confer mechanosensing capabilities on ASIC-1 (the trimeric non-MSC, acid-sensing ion channel-1) and a C-terminal pore module, which influences conductance, selectivity, and channel inactivation. Repeated stimulation can cause domain fracture and diffusion of these channels leading to synchronous loss of inactivation. The reconstituted channels spontaneously open only in asymmetric bilayers but lack inactivation. Mutations that cause hereditary xerocytosis alter PIEZO1 kinetics. The kinetics of the wild-type PIEZO1 and alterations thereof in mutants (M2225R, R2456K, and DhPIEZO1) are summarized in the form of a quantitative model and hosted online. The pore is permeable to alkali ions although Li+ permeates poorly. Divalent cations, notably Ca2+, traverse the channel and inhibit the flux of monovalents. The large monovalent organic cations such as tetramethyl ammonium and tetraethyl ammonium can traverse the channel, but slowly, suggesting a pore diameter of ∼8Å, and the estimated in-plane area change upon opening is around 6-20nm2. Ruthenium red can enter the channel only from the extracellular side and seems to bind in a pocket close to residue 2496.
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Affiliation(s)
- R Gnanasambandam
- State University of New York at Buffalo, Buffalo, NY, United States
| | - P A Gottlieb
- State University of New York at Buffalo, Buffalo, NY, United States
| | - F Sachs
- State University of New York at Buffalo, Buffalo, NY, United States
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16
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Brauers E, Roos A, Kollipara L, Zahedi RP, Beckmann A, Mohanadas N, Bauer H, Häusler M, Thoma S, Kress W, Senderek J, Weis J. The Caveolin-3 G56S sequence variant of unknown significance: Muscle biopsy findings and functional cell biological analysis. Proteomics Clin Appl 2016; 11. [PMID: 27739254 PMCID: PMC5248598 DOI: 10.1002/prca.201600007] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2016] [Revised: 08/09/2016] [Accepted: 10/11/2016] [Indexed: 12/31/2022]
Abstract
Purpose In the era of next‐generation sequencing, we are increasingly confronted with sequence variants of unknown significance. This phenomenon is also known for variations in Caveolin‐3 and can complicate the molecular diagnosis of the disease. Here, we aimed to study the ambiguous character of the G56S Caveolin‐3 variant. Experimental design A comprehensive approach combining genetic and morphological studies of muscle derived from carriers of the G56S Caveolin‐3 variant were carried out and linked to biochemical assays (including phosphoblot studies and proteome profiling) and morphological investigations of cultured myoblasts. Results Muscles showed moderate chronic myopathic changes in all carriers of the variant. Myogenic RCMH cells expressing the G56S Caveolin‐3 protein presented irregular Caveolin‐3 deposits within the Golgi in addition to a regular localization of the protein to the plasma membrane. This result was associated with abnormal findings on the ultra‐structural level. Phosphoblot studies revealed that G56S affects EGFR‐signaling. Proteomic profiling demonstrated alterations in levels of physiologically relevant proteins which are indicative for antagonization of G56S Caveolin‐3 expression. Remarkably, some proteomic alterations were enhanced by osmotic/mechanical stress. Conclusions and clinical relevance Our studies suggest that G56S might influence the manifestation of myopathic changes upon the presence of additional cellular stress burden. Results of our studies moreover improve the current understanding of (genetic) causes of myopathic disorders classified as caveolinopathies.
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Affiliation(s)
- Eva Brauers
- Institute of Neuropathology, RWTH Aachen University Hospital, Aachen, Germany
| | - Andreas Roos
- Institute of Neuropathology, RWTH Aachen University Hospital, Aachen, Germany.,Leibniz-Institut für Analytische Wissenschaften - ISAS e.V, Dortmund, Germany
| | | | - René P Zahedi
- Leibniz-Institut für Analytische Wissenschaften - ISAS e.V, Dortmund, Germany
| | - Alf Beckmann
- Medizinisches Versorgungszentrum Dr. Eberhard und Partner, Dortmund, Germany
| | - Nilane Mohanadas
- Institute of Neuropathology, RWTH Aachen University Hospital, Aachen, Germany
| | - Hartmut Bauer
- Department of Neurology, Marien-Hospital, Euskirchen, Germany
| | - Martin Häusler
- Department of Pediatrics, RWTH Aachen University Hospital, Aachen, Germany
| | | | - Wolfram Kress
- Institute of Human Genetics, University of Würzburg, Würzburg, Germany
| | - Jan Senderek
- Friedrich-Baur-Institut, Neurologische Klinik und Poliklinik, Ludwig-Maximilians-University, München, Germany
| | - Joachim Weis
- Institute of Neuropathology, RWTH Aachen University Hospital, Aachen, Germany
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Cox CD, Bavi N, Martinac B. Origin of the Force: The Force-From-Lipids Principle Applied to Piezo Channels. CURRENT TOPICS IN MEMBRANES 2016; 79:59-96. [PMID: 28728824 DOI: 10.1016/bs.ctm.2016.09.001] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Piezo channels are a ubiquitously expressed, principal type of molecular force sensor in eukaryotes. They enable cells to decode a myriad of physical stimuli and are essential components of numerous mechanosensory processes. Central to their physiological role is the ability to change conformation in response to mechanical force. Here we discuss the evolutionary origin of Piezo in relation to other MS channels in addition to the force that gates Piezo channels. In particular, we discuss whether Piezo channels are inherently mechanosensitive in accordance with the force-from-lipid paradigm which has been firmly established for bacterial MS channels and two-pore domain K+ (K2P) channels. We also discuss the evidence supporting a reliance on or direct interaction with structural scaffold proteins of the cytoskeleton and extracellular matrix according to the force-from-filament principle. In doing so, we explain the false dichotomy that these distinctions represent. We also discuss the possible unifying models that shed light on channel mechanosensitivity at the molecular level.
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Affiliation(s)
- C D Cox
- Victor Chang Cardiac Research Institute, Darlinghurst, NSW, Australia; University of New South Wales, Darlinghurst, NSW, Australia
| | - N Bavi
- Victor Chang Cardiac Research Institute, Darlinghurst, NSW, Australia; University of New South Wales, Darlinghurst, NSW, Australia
| | - B Martinac
- Victor Chang Cardiac Research Institute, Darlinghurst, NSW, Australia; University of New South Wales, Darlinghurst, NSW, Australia
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Wang J, Ma Y, Sachs F, Li J, Suchyna TM. GsMTx4-D is a cardioprotectant against myocardial infarction during ischemia and reperfusion. J Mol Cell Cardiol 2016; 98:83-94. [PMID: 27423272 DOI: 10.1016/j.yjmcc.2016.07.005] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/17/2016] [Revised: 06/25/2016] [Accepted: 07/12/2016] [Indexed: 01/01/2023]
Abstract
GsMTx4 is a selective inhibitor of cationic mechanosensitive ion channels (MSCs) and has helped establish the role of MSCs in cardiac physiology. Inhomogeneous local mechanical stresses due to hypercontracture and swelling during ischemic reperfusion injury (IRI) likely induce elevated MSC activity that can contribute to cation imbalance. The aim of this study was to determine if the D enantiomer of GsMTx4 can act as a cardioprotectant in a mouse IRI model. Ischemia and reperfusion involved ligating a coronary artery followed by release of the ligature. GsMTx4-D was tested by either acute intravenous injection during the ischemic event or by two day pretreatment by intraperitoneal injection, both methods achieving similar results. Based on pharmacokinetic studies, GsMTx4-D dosage was set to achieve expected plasma concentrations between 50 and 5000nM and heart tissue concentrations between 1 and 200nM by intravenous injection. Relative to vehicle injected animals, GsMTx4-D reduced infarct area by ~40% for acute and pretreated animals for both 20 and 45min ischemic challenges. Many indicators of cardiac output were indistinguishable from sham-treated control hearts after GsMTx4-D treatment showing improvement at both 4 and 48h post ischemia, and premature ventricular beats immediately following reperfusion were also significantly reduced. To determine if GsMTx4-D cardioprotection could act directly at the level of cardiomyocytes, we tested its effects in vitro on indicators of IRI damage like cation influx and activation of inflammatory kinases in isolated myocytes cultured under hypoxic conditions. Hypoxia challenged cardiomyocytes treated with 10μM GsMTx4-D showed improved contractility and near normal contraction-related Ca(2+) influx. GsMTx4-D inhibited indicators of ischemic damage such as the apoptotic signaling system JNK/c-Jun, but also inhibited the energy response signaling system Akt kinase. We conclude that GsMTx4-D is a potent cardioprotectant in vivo that may act directly on cardiomyocytes and potentially be useful in multidrug strategies to treat IRI.
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Affiliation(s)
- Jinli Wang
- Department of Pharmacology and Toxicology, School of Medicine and Biomedical Sciences, State University of New York at Buffalo, Buffalo, NY 14214, United States
| | - Yina Ma
- Department of Pharmacology and Toxicology, School of Medicine and Biomedical Sciences, State University of New York at Buffalo, Buffalo, NY 14214, United States
| | - Frederick Sachs
- Department of Physiology and Biophysics, School of Medicine and Biomedical Sciences, State University of New York at Buffalo, Buffalo, NY 14214, United States
| | - Ji Li
- Department of Pharmacology and Toxicology, School of Medicine and Biomedical Sciences, State University of New York at Buffalo, Buffalo, NY 14214, United States
| | - Thomas M Suchyna
- Department of Physiology and Biophysics, School of Medicine and Biomedical Sciences, State University of New York at Buffalo, Buffalo, NY 14214, United States.
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Gilbert G, Ducret T, Savineau JP, Marthan R, Quignard JF. Caveolae are involved in mechanotransduction during pulmonary hypertension. Am J Physiol Lung Cell Mol Physiol 2016; 310:L1078-87. [PMID: 27016585 DOI: 10.1152/ajplung.00198.2015] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2015] [Accepted: 03/21/2016] [Indexed: 12/12/2022] Open
Abstract
Caveolae are stiff plasma membrane microdomains implicated in various cell response mechanisms like Ca(2+) signaling and mechanotransduction. Pulmonary arterial smooth muscle cells (PASMC) transduce mechanical stimuli into Ca(2+) increase via plasma membrane stretch-activated channels (SAC). This mechanotransduction process is modified in pulmonary hypertension (PH) during which stretch forces are increased by the increase in arterial blood pressure. We propose to investigate how caveolae are involved in the pathophysiology of PH and particularly in mechanotransduction. PASMC were freshly isolated from control rats (Ctrl rats) and rats suffering from PH induced by 3 wk of chronic hypoxia (CH rats). Using a caveolae disrupter (methyl-β-cyclodextrin), we showed that SAC activity measured by patch-clamp, stretch-induced Ca(2+) increase measured with indo-1 probe and pulmonary arterial ring contraction to osmotic shock are enhanced in Ctrl rats when caveolae are disrupted. In CH rats, SAC activity, Ca(2+), and contraction responses to stretch are all higher compared with Ctrl rats. However, in contrast to Ctrl rats, caveolae disruption in CH-PASMC, reduces SAC activity, Ca(2+) responses to stretch and arterial contractions. Furthermore, by means of immunostainings and transmission electron microscopy, we observed that caveolae and caveolin-1 are expressed in PASMC from both Ctrl and CH rats and localize close to subplasmalemmal sarcoplasmic reticulum (ryanodine receptors) and mitochondria, thus facilitating Ca(2+) exchanges, particularly in CH. In conclusion, caveolae are implicated in mechanotransduction in Ctrl PASMC by buffering mechanical forces. In PH-PASMC, caveolae form a distinct Ca(2+) store facilitating Ca(2+) coupling between SAC and sarcoplasmic reticulum.
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Affiliation(s)
- Guillaume Gilbert
- Centre de Recherche Cardio-Thoracique de Bordeaux, Université de Bordeaux, Bordeaux, France; and Centre de Recherche Cardio-Thoracique de Bordeaux, INSERM U1045, Bordeaux, France
| | - Thomas Ducret
- Centre de Recherche Cardio-Thoracique de Bordeaux, Université de Bordeaux, Bordeaux, France; and Centre de Recherche Cardio-Thoracique de Bordeaux, INSERM U1045, Bordeaux, France
| | - Jean-Pierre Savineau
- Centre de Recherche Cardio-Thoracique de Bordeaux, Université de Bordeaux, Bordeaux, France; and Centre de Recherche Cardio-Thoracique de Bordeaux, INSERM U1045, Bordeaux, France
| | - Roger Marthan
- Centre de Recherche Cardio-Thoracique de Bordeaux, Université de Bordeaux, Bordeaux, France; and Centre de Recherche Cardio-Thoracique de Bordeaux, INSERM U1045, Bordeaux, France
| | - Jean-François Quignard
- Centre de Recherche Cardio-Thoracique de Bordeaux, Université de Bordeaux, Bordeaux, France; and Centre de Recherche Cardio-Thoracique de Bordeaux, INSERM U1045, Bordeaux, France
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Allen DG, Whitehead NP, Froehner SC. Absence of Dystrophin Disrupts Skeletal Muscle Signaling: Roles of Ca2+, Reactive Oxygen Species, and Nitric Oxide in the Development of Muscular Dystrophy. Physiol Rev 2016; 96:253-305. [PMID: 26676145 DOI: 10.1152/physrev.00007.2015] [Citation(s) in RCA: 272] [Impact Index Per Article: 34.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Dystrophin is a long rod-shaped protein that connects the subsarcolemmal cytoskeleton to a complex of proteins in the surface membrane (dystrophin protein complex, DPC), with further connections via laminin to other extracellular matrix proteins. Initially considered a structural complex that protected the sarcolemma from mechanical damage, the DPC is now known to serve as a scaffold for numerous signaling proteins. Absence or reduced expression of dystrophin or many of the DPC components cause the muscular dystrophies, a group of inherited diseases in which repeated bouts of muscle damage lead to atrophy and fibrosis, and eventually muscle degeneration. The normal function of dystrophin is poorly defined. In its absence a complex series of changes occur with multiple muscle proteins showing reduced or increased expression or being modified in various ways. In this review, we will consider the various proteins whose expression and function is changed in muscular dystrophies, focusing on Ca(2+)-permeable channels, nitric oxide synthase, NADPH oxidase, and caveolins. Excessive Ca(2+) entry, increased membrane permeability, disordered caveolar function, and increased levels of reactive oxygen species are early changes in the disease, and the hypotheses for these phenomena will be critically considered. The aim of the review is to define the early damage pathways in muscular dystrophy which might be appropriate targets for therapy designed to minimize the muscle degeneration and slow the progression of the disease.
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Affiliation(s)
- David G Allen
- Sydney Medical School & Bosch Institute, University of Sydney, New South Wales, Australia; and Department of Physiology & Biophysics, University of Washington, Seattle, Washington
| | - Nicholas P Whitehead
- Sydney Medical School & Bosch Institute, University of Sydney, New South Wales, Australia; and Department of Physiology & Biophysics, University of Washington, Seattle, Washington
| | - Stanley C Froehner
- Sydney Medical School & Bosch Institute, University of Sydney, New South Wales, Australia; and Department of Physiology & Biophysics, University of Washington, Seattle, Washington
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Bavi O, Cox CD, Vossoughi M, Naghdabadi R, Jamali Y, Martinac B. Influence of Global and Local Membrane Curvature on Mechanosensitive Ion Channels: A Finite Element Approach. MEMBRANES 2016; 6:membranes6010014. [PMID: 26861405 PMCID: PMC4812420 DOI: 10.3390/membranes6010014] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/01/2016] [Revised: 01/24/2016] [Accepted: 01/25/2016] [Indexed: 11/25/2022]
Abstract
Mechanosensitive (MS) channels are ubiquitous molecular force sensors that respond to a number of different mechanical stimuli including tensile, compressive and shear stress. MS channels are also proposed to be molecular curvature sensors gating in response to bending in their local environment. One of the main mechanisms to functionally study these channels is the patch clamp technique. However, the patch of membrane surveyed using this methodology is far from physiological. Here we use continuum mechanics to probe the question of how curvature, in a standard patch clamp experiment, at different length scales (global and local) affects a model MS channel. Firstly, to increase the accuracy of the Laplace’s equation in tension estimation in a patch membrane and to be able to more precisely describe the transient phenomena happening during patch clamping, we propose a modified Laplace’s equation. Most importantly, we unambiguously show that the global curvature of a patch, which is visible under the microscope during patch clamp experiments, is of negligible energetic consequence for activation of an MS channel in a model membrane. However, the local curvature (RL < 50) and the direction of bending are able to cause considerable changes in the stress distribution through the thickness of the membrane. Not only does local bending, in the order of physiologically relevant curvatures, cause a substantial change in the pressure profile but it also significantly modifies the stress distribution in response to force application. Understanding these stress variations in regions of high local bending is essential for a complete understanding of the effects of curvature on MS channels.
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Affiliation(s)
- Omid Bavi
- Institute for Nanoscience and Nanotechnology, Sharif University of Technology, 89694-14588 Tehran, Iran.
- Molecular Cardiology and Biophysics Division/Mechanosensory Biophysics Laboratory, Victor Chang Cardiac Research Institute, Darlinghurst, NSW 2010, Australia.
| | - Charles D Cox
- Molecular Cardiology and Biophysics Division/Mechanosensory Biophysics Laboratory, Victor Chang Cardiac Research Institute, Darlinghurst, NSW 2010, Australia.
| | - Manouchehr Vossoughi
- Institute for Nanoscience and Nanotechnology, Sharif University of Technology, 89694-14588 Tehran, Iran.
- Biochemical & Bioenvironmental Research Center (BBRC), 89694-14588 Tehran, Iran.
| | - Reza Naghdabadi
- Institute for Nanoscience and Nanotechnology, Sharif University of Technology, 89694-14588 Tehran, Iran.
- Department of Mechanical Engineering, Sharif University of Technology, 89694-14588 Tehran, Iran.
| | - Yousef Jamali
- Department of Mathematics and Bioscience, Tarbiat Modares University, Jalal Ale Ahmad Highway, 14115-111 Tehran, Iran.
- Computational physical Sciences Research Laboratory, School of Nano-Science, Institute for Research in Fundamental Sciences (IPM), 19395-5531 Tehran, Iran.
| | - Boris Martinac
- Molecular Cardiology and Biophysics Division/Mechanosensory Biophysics Laboratory, Victor Chang Cardiac Research Institute, Darlinghurst, NSW 2010, Australia.
- St Vincent's Clinical School, Faculty of Medicine, University of New South Wales, Darlinghurst, NSW 2010, Australia.
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Qi Y, Andolfi L, Frattini F, Mayer F, Lazzarino M, Hu J. Membrane stiffening by STOML3 facilitates mechanosensation in sensory neurons. Nat Commun 2015; 6:8512. [PMID: 26443885 PMCID: PMC4633829 DOI: 10.1038/ncomms9512] [Citation(s) in RCA: 111] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2015] [Accepted: 09/01/2015] [Indexed: 12/21/2022] Open
Abstract
Sensing force is crucial to maintain the viability of all living cells. Despite its fundamental importance, how force is sensed at the molecular level remains largely unknown. Here we show that stomatin-like protein-3 (STOML3) controls membrane mechanics by binding cholesterol and thus facilitates force transfer and tunes the sensitivity of mechano-gated channels, including Piezo channels. STOML3 is detected in cholesterol-rich lipid rafts. In mouse sensory neurons, depletion of cholesterol and deficiency of STOML3 similarly and interdependently attenuate mechanosensitivity while modulating membrane mechanics. In heterologous systems, intact STOML3 is required to maintain membrane mechanics to sensitize Piezo1 and Piezo2 channels. In C57BL/6N, but not STOML3−/− mice, tactile allodynia is attenuated by cholesterol depletion, suggesting that membrane stiffening by STOML3 is essential for mechanical sensitivity. Targeting the STOML3–cholesterol association might offer an alternative strategy for control of chronic pain. To maintain viability, cells must be able to sense and respond to mechanical stimuli. Here, Qi et al. show that the STOML3 protein acts in mechanosensation by binding cholesterol and regulating membrane stiffness which can in turn regulate ion flux through mechanosensitive channels.
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Affiliation(s)
- Yanmei Qi
- Sensory Mechanotransduction, Centre for Integrative Neuroscience, Otfried-Mueller-Strasse 25, 72076 Tuebingen, Germany
| | - Laura Andolfi
- Istituto Officina dei Materiali Consiglio Nazionale delle Ricerche, Laboratorio TASC, 34149 Basovizza, Trieste, Italy
| | - Flavia Frattini
- Sensory Mechanotransduction, Centre for Integrative Neuroscience, Otfried-Mueller-Strasse 25, 72076 Tuebingen, Germany
| | - Florian Mayer
- Sensory Mechanotransduction, Centre for Integrative Neuroscience, Otfried-Mueller-Strasse 25, 72076 Tuebingen, Germany
| | - Marco Lazzarino
- Istituto Officina dei Materiali Consiglio Nazionale delle Ricerche, Laboratorio TASC, 34149 Basovizza, Trieste, Italy
| | - Jing Hu
- Sensory Mechanotransduction, Centre for Integrative Neuroscience, Otfried-Mueller-Strasse 25, 72076 Tuebingen, Germany
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Sachs F. Mechanical transduction by ion channels: A cautionary tale. World J Neurol 2015; 5:74-87. [PMID: 28078202 PMCID: PMC5221657 DOI: 10.5316/wjn.v5.i3.74] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/10/2014] [Revised: 08/23/2014] [Accepted: 07/17/2015] [Indexed: 02/06/2023] Open
Abstract
Mechanical transduction by ion channels occurs in all cells. The physiological functions of these channels have just begun to be elaborated, but if we focus on the upper animal kingdom, these channels serve the common sensory services such as hearing and touch, provide the central nervous system with information on the force and position of muscles and joints, and they provide the autonomic system with information about the filling of hollow organs such as blood vessels. However, all cells of the body have mechanosensitive channels (MSCs), including red cells. Most of these channels are cation selective and are activated by bilayer tension. There are also K+ selective MSCs found commonly in neurons where they may be responsible for both general anesthesia and knockout punches in the boxing ring by hyperpolarizing neurons to reduce excitability. The cationic MSCs are typically inactive under normal mechanical stress, but open under pathologic stress. The channels are normally inactive because they are shielded from stress by the cytoskeleton. The cationic MSCs are specifically blocked by the externally applied peptide GsMtx4 (aka, AT-300). This is the first drug of its class and provides a new approach to many pathologies since it is nontoxic, non-immunogenic, stable in a biological environment and has a long pharmacokinetic lifetime. Pathologies involving excessive stress are common. They produce cardiac arrhythmias, contraction in stretched dystrophic muscle, xerocytotic and sickled red cells, etc. The channels seem to function primarily as “fire alarms”, providing feedback to the cytoskeleton that a region of the bilayer is under excessive tension and needs reinforcing. The eukaryotic forms of MSCs have only been cloned in recent years and few people have experience working with them. “Newbies” need to become aware of the technology, potential artifacts, and the fundamentals of mechanics. The most difficult problem in studying MSCs is that the actual stimulus, the force applied to the channel, is not known. We don’t have direct access to the channels themselves but only to larger regions of the membrane as seen in patches. Cortical forces are shared by the bilayer, the cytoskeleton and the extracellular matrix. How much of an applied stimulus reaches the channel is unknown. Furthermore, many of these channels exist in spatial domains where the forces within a domain are different from forces outside the domain, although we often hope they are proportional. This review is intended to be a guide for new investigators who want to study mechanosensitive ion channels.
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25
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Echarri A, Del Pozo MA. Caveolae - mechanosensitive membrane invaginations linked to actin filaments. J Cell Sci 2015; 128:2747-58. [PMID: 26159735 DOI: 10.1242/jcs.153940] [Citation(s) in RCA: 126] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
An essential property of the plasma membrane of mammalian cells is its plasticity, which is required for sensing and transmitting of signals, and for accommodating the tensional changes imposed by its environment or its own biomechanics. Caveolae are unique invaginated membrane nanodomains that play a major role in organizing signaling, lipid homeostasis and adaptation to membrane tension. Caveolae are frequently associated with stress fibers, a major regulator of membrane tension and cell shape. In this Commentary, we discuss recent studies that have provided new insights into the function of caveolae and have shown that trafficking and organization of caveolae are tightly regulated by stress-fiber regulators, providing a functional link between caveolae and stress fibers. Furthermore, the tension in the plasma membrane determines the curvature of caveolae because they flatten at high tension and invaginate at low tension, thus providing a tension-buffering system. Caveolae also regulate multiple cellular pathways, including RhoA-driven actomyosin contractility and other mechanosensitive pathways, suggesting that caveolae could couple mechanotransduction pathways to actin-controlled changes in tension through their association with stress fibers. Therefore, we argue here that the association of caveolae with stress fibers could provide an important strategy for cells to deal with mechanical stress.
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Affiliation(s)
- Asier Echarri
- Integrin Signaling Laboratory, Cell Biology & Physiology Program, Cell & Developmental Biology Area, Centro Nacional de Investigaciones Cardiovasculares Carlos III (CNIC), Melchor Fernández Almagro, 3, Madrid 28029, Spain
| | - Miguel A Del Pozo
- Integrin Signaling Laboratory, Cell Biology & Physiology Program, Cell & Developmental Biology Area, Centro Nacional de Investigaciones Cardiovasculares Carlos III (CNIC), Melchor Fernández Almagro, 3, Madrid 28029, Spain
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Lansman JB. Utrophin suppresses low frequency oscillations and coupled gating of mechanosensitive ion channels in dystrophic skeletal muscle. Channels (Austin) 2015; 9:145-60. [PMID: 25941878 DOI: 10.1080/19336950.2015.1040211] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022] Open
Abstract
An absence of utrophin in muscle from mdx mice prolongs the open time of single mechanosensitive channels. On a time scale much longer than the duration of individual channel activations, genetic depletion of utrophin produces low frequency oscillations of channel open probability. Oscillatory channel opening occurred in the dystrophin/utrophin mutants, but was absent in wild-type and mdx fibers. By contrast, small conductance channels showed random gating behavior when present in the same patch. Applying a negative pressure to a patch on a DKO fiber produced a burst of mode II activity, but channels subsequently closed and remained silent for tens of seconds during the maintained pressure stimulus. In addition, simultaneous opening of multiple MS channels could be frequently observed in recordings from patches on DKO fibers, but only rarely in wild-type and mdx muscle. A model which accounts for the single-channel data is proposed in which utrophin acts as gating spring which maintains the mechanical stability a caveolar-like compartment. The state of this compartment is suggested to be dynamic; its continuity with the extracellular surface varying over seconds to minutes. Loss of the mechanical stability of this compartment contributes to pathogenic Ca(2+) entry through MS channels in Duchenne dystrophy.
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Affiliation(s)
- Jeffry B Lansman
- a Department of Cellular and Molecular Pharmacology ; School of Medicine; University of California San Francisco; San Francisco , CA USA
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27
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Sachs F, Sivaselvan MV. Cell volume control in three dimensions: Water movement without solute movement. ACTA ACUST UNITED AC 2015; 145:373-80. [PMID: 25870207 PMCID: PMC4411252 DOI: 10.1085/jgp.201411297] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Affiliation(s)
- Frederick Sachs
- Department of Physiology and Biophysics and Department of Civil, Structural and Environmental Engineering, University at Buffalo, The State University of New York, Buffalo, NY 14260
| | - Mettupalayam V Sivaselvan
- Department of Physiology and Biophysics and Department of Civil, Structural and Environmental Engineering, University at Buffalo, The State University of New York, Buffalo, NY 14260
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28
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Barrientos G, Llanos P, Hidalgo J, Bolaños P, Caputo C, Riquelme A, Sánchez G, Quest AFG, Hidalgo C. Cholesterol removal from adult skeletal muscle impairs excitation-contraction coupling and aging reduces caveolin-3 and alters the expression of other triadic proteins. Front Physiol 2015; 6:105. [PMID: 25914646 PMCID: PMC4392612 DOI: 10.3389/fphys.2015.00105] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2015] [Accepted: 03/16/2015] [Indexed: 12/30/2022] Open
Abstract
Cholesterol and caveolin are integral membrane components that modulate the function/location of many cellular proteins. Skeletal muscle fibers, which have unusually high cholesterol levels in transverse tubules, express the caveolin-3 isoform but its association with transverse tubules remains contentious. Cholesterol removal impairs excitation–contraction (E–C) coupling in amphibian and mammalian fetal skeletal muscle fibers. Here, we show that treating single muscle fibers from adult mice with the cholesterol removing agent methyl-β-cyclodextrin decreased fiber cholesterol by 26%, altered the location pattern of caveolin-3 and of the voltage dependent calcium channel Cav1.1, and suppressed or reduced electrically evoked Ca2+ transients without affecting membrane integrity or causing sarcoplasmic reticulum (SR) calcium depletion. We found that transverse tubules from adult muscle and triad fractions that contain ~10% attached transverse tubules, but not SR membranes, contained caveolin-3 and Cav1.1; both proteins partitioned into detergent-resistant membrane fractions highly enriched in cholesterol. Aging entails significant deterioration of skeletal muscle function. We found that triad fractions from aged rats had similar cholesterol and RyR1 protein levels compared to triads from young rats, but had lower caveolin-3 and glyceraldehyde 3-phosphate dehydrogenase and increased Na+/K+-ATPase protein levels. Both triad fractions had comparable NADPH oxidase (NOX) activity and protein content of NOX2 subunits (p47phox and gp91phox), implying that NOX activity does not increase during aging. These findings show that partial cholesterol removal impairs E–C coupling and alters caveolin-3 and Cav1.1 location pattern, and that aging reduces caveolin-3 protein content and modifies the expression of other triadic proteins. We discuss the possible implications of these findings for skeletal muscle function in young and aged animals.
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Affiliation(s)
- Genaro Barrientos
- Physiology and Biophysics Program, Institute of Biomedical Sciences, School of Medicine, University of Chile Santiago, Chile
| | - Paola Llanos
- Institute for Research in Dental Sciences, Faculty of Dentistry, University of Chile Santiago, Chile
| | - Jorge Hidalgo
- Physiology and Biophysics Program, Institute of Biomedical Sciences, School of Medicine, University of Chile Santiago, Chile
| | - Pura Bolaños
- Centre of Biophysics and Biochemistry, Venezuelan Institute for Scientific Research Caracas, Venezuela
| | - Carlo Caputo
- Centre of Biophysics and Biochemistry, Venezuelan Institute for Scientific Research Caracas, Venezuela
| | - Alexander Riquelme
- Biomedical Neuroscience Institute, School of Medicine, University of Chile Santiago, Chile
| | - Gina Sánchez
- Biomedical Neuroscience Institute, School of Medicine, University of Chile Santiago, Chile ; Pathophysiology Program, Institute of Biomedical Sciences, School of Medicine, University of Chile Santiago, Chile ; Center for Molecular Studies of the Cell, School of Medicine, University of Chile Santiago, Chile
| | - Andrew F G Quest
- Center for Molecular Studies of the Cell, School of Medicine, University of Chile Santiago, Chile ; Laboratory of Cell Communication, Program in Cell and Molecular Biology, Institute of Biomedical Sciences, School of Medicine, University of Chile Santiago, Chile ; Advanced Center for Chronic Diseases and Network for Metabolic Stress Signaling, University of Chile Santiago, Chile
| | - Cecilia Hidalgo
- Physiology and Biophysics Program, Institute of Biomedical Sciences, School of Medicine, University of Chile Santiago, Chile ; Biomedical Neuroscience Institute, School of Medicine, University of Chile Santiago, Chile ; Center for Molecular Studies of the Cell, School of Medicine, University of Chile Santiago, Chile
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29
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Pfeiffer ER, Wright AT, Edwards AG, Stowe JC, McNall K, Tan J, Niesman I, Patel HH, Roth DM, Omens JH, McCulloch AD. Caveolae in ventricular myocytes are required for stretch-dependent conduction slowing. J Mol Cell Cardiol 2014; 76:265-74. [PMID: 25257915 DOI: 10.1016/j.yjmcc.2014.09.014] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/04/2014] [Revised: 08/25/2014] [Accepted: 09/13/2014] [Indexed: 12/23/2022]
Abstract
Mechanical stretch of cardiac muscle modulates action potential propagation velocity, causing potentially arrhythmogenic conduction slowing. The mechanisms by which stretch alters cardiac conduction remain unknown, but previous studies suggest that stretch can affect the conformation of caveolae in myocytes and other cell types. We tested the hypothesis that slowing of action potential conduction due to cardiac myocyte stretch is dependent on caveolae. Cardiac action potential propagation velocities, measured by optical mapping in isolated mouse hearts and in micropatterned mouse cardiomyocyte cultures, decreased reversibly with volume loading or stretch, respectively (by 19±5% and 26±4%). Stretch-dependent conduction slowing was not altered by stretch-activated channel blockade with gadolinium or by GsMTx-4 peptide, but was inhibited when caveolae were disrupted via genetic deletion of caveolin-3 (Cav3 KO) or membrane cholesterol depletion by methyl-β-cyclodextrin. In wild-type mouse hearts, stretch coincided with recruitment of caveolae to the sarcolemma, as observed by electron microscopy. In myocytes from wild-type but not Cav3 KO mice, stretch significantly increased cell membrane capacitance (by 98±64%), electrical time constant (by 285±149%), and lipid recruitment to the bilayer (by 84±39%). Recruitment of caveolae to the sarcolemma during physiologic cardiomyocyte stretch slows ventricular action potential propagation by increasing cell membrane capacitance.
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Affiliation(s)
- E R Pfeiffer
- Department of Bioengineering, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0412, USA
| | - A T Wright
- Department of Bioengineering, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0412, USA
| | - A G Edwards
- Department of Bioengineering, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0412, USA
| | - J C Stowe
- Department of Bioengineering, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0412, USA
| | - K McNall
- Department of Bioengineering, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0412, USA
| | - J Tan
- Department of Bioengineering, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0412, USA
| | - I Niesman
- Department of Anesthesiology, VA San Diego Healthcare System, and University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093-9125, USA
| | - H H Patel
- Department of Anesthesiology, VA San Diego Healthcare System, and University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093-9125, USA
| | - D M Roth
- Department of Anesthesiology, VA San Diego Healthcare System, and University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093-9125, USA
| | - J H Omens
- Department of Bioengineering, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0412, USA; Department of Medicine, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0613, USA
| | - A D McCulloch
- Department of Bioengineering, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0412, USA; Department of Medicine, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0613, USA.
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30
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Tan N, Lansman JB. Utrophin regulates modal gating of mechanosensitive ion channels in dystrophic skeletal muscle. J Physiol 2014; 592:3303-23. [PMID: 24879867 DOI: 10.1113/jphysiol.2014.274332] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Dystrophin is a large, submembrane cytoskeletal protein, absence of which causes Duchenne muscular dystrophy. Utrophin is a dystrophin homologue found in both muscle and brain whose physiological function is unknown. Recordings of single-channel activity were made from membrane patches on skeletal muscle from mdx, mdx/utrn(+/-) heterozygotes and mdx/utrn(-/-) double knockout mice to investigate the role of these cytoskeletal proteins in mechanosensitive (MS) channel gating. We find complex, gene dose-dependent effects of utrophin depletion in dystrophin-deficient mdx muscle: (1) increased MS channel open probability, (2) a shift of MS channel gating to larger pressures, (3) appearance of modal gating of MS channels and small conductance channels and (4) expression of large conductance MS channels. We suggest a physical model in which utrophin acts as a scaffolding protein that stabilizes lipid microdomains and clusters MS channel subunits. Depletion of utrophin disrupts domain composition in a manner that favours open channel area expansion, as well as allowing diffusion and aggregation of additional MS channel subunits.
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Affiliation(s)
- Nhi Tan
- Department of Cellular and Molecular Pharmacology, School of Medicine, University of California, San Francisco, San Francisco, CA, 94143-0450, USA
| | - Jeffry B Lansman
- Department of Cellular and Molecular Pharmacology, School of Medicine, University of California, San Francisco, San Francisco, CA, 94143-0450, USA
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