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Muriel J, Lukyanenko V, Kwiatkowski TA, Li Y, Bhattacharya S, Banford KK, Garman D, Bulgart HR, Sutton RB, Weisleder N, Bloch RJ. Nanodysferlins support membrane repair and binding to TRIM72/MG53 but do not localize to t-tubules or stabilize Ca 2+ signaling. Mol Ther Methods Clin Dev 2024; 32:101257. [PMID: 38779337 PMCID: PMC11109471 DOI: 10.1016/j.omtm.2024.101257] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2024] [Accepted: 04/22/2024] [Indexed: 05/25/2024]
Abstract
Mutations in the DYSF gene, encoding the protein dysferlin, lead to several forms of muscular dystrophy. In healthy skeletal muscle, dysferlin concentrates in the transverse tubules and is involved in repairing the sarcolemma and stabilizing Ca2+ signaling after membrane disruption. The DYSF gene encodes 7-8 C2 domains, several Fer and Dysf domains, and a C-terminal transmembrane sequence. Because its coding sequence is too large to package in adeno-associated virus, the full-length sequence is not amenable to current gene delivery methods. Thus, we have examined smaller versions of dysferlin, termed "nanodysferlins," designed to eliminate several C2 domains, specifically C2 domains D, E, and F; B, D, and E; and B, D, E, and F. We also generated a variant by replacing eight amino acids in C2G in the nanodysferlin missing domains D through F. We electroporated dysferlin-null A/J mouse myofibers with Venus fusion constructs of these variants, or as untagged nanodysferlins together with GFP, to mark transfected fibers We found that, although these nanodysferlins failed to concentrate in transverse tubules, three of them supported membrane repair after laser wounding while all four bound the membrane repair protein, TRIM72/MG53, similar to WT dysferlin. By contrast, they failed to suppress Ca2+ waves after myofibers were injured by mild hypoosmotic shock. Our results suggest that the internal C2 domains of dysferlin are required for normal t-tubule localization and Ca2+ signaling and that membrane repair does not require these C2 domains.
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Affiliation(s)
- Joaquin Muriel
- Department of Physiology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Valeriy Lukyanenko
- Department of Physiology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Thomas A. Kwiatkowski
- Department of Physiology and Cell Biology, The Ohio State University, Columbus, OH 43210, USA
| | - Yi Li
- Department of Physiology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Sayak Bhattacharya
- Department of Physiology and Cell Biology, The Ohio State University, Columbus, OH 43210, USA
| | - Kassidy K. Banford
- Department of Physiology and Cell Biology, The Ohio State University, Columbus, OH 43210, USA
| | - Daniel Garman
- Department of Physiology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Hannah R. Bulgart
- Department of Physiology and Cell Biology, The Ohio State University, Columbus, OH 43210, USA
| | - Roger B. Sutton
- Department of Cell Physiology and Molecular Biophysics, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA
| | - Noah Weisleder
- Department of Physiology and Cell Biology, The Ohio State University, Columbus, OH 43210, USA
| | - Robert J. Bloch
- Department of Physiology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
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Rudolph TE, Roths M, Freestone AD, Yap SQ, Michael A, Rhoads RP, White-Springer SH, Baumgard LH, Selsby JT. Biological sex impacts oxidative stress in skeletal muscle in a porcine heat stress model. Am J Physiol Regul Integr Comp Physiol 2024; 326:R578-R587. [PMID: 38708546 PMCID: PMC11381024 DOI: 10.1152/ajpregu.00268.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2023] [Revised: 04/03/2024] [Accepted: 04/25/2024] [Indexed: 05/07/2024]
Abstract
Oxidative stress contributes to heat stress (HS)-mediated alterations in skeletal muscle; however, the extent to which biological sex mediates oxidative stress during HS remains unknown. We hypothesized muscle from males would be more resistant to oxidative stress caused by HS than muscle from females. To address this, male and female pigs were housed in thermoneutral conditions (TN; 20.8 ± 1.6°C; 62.0 ± 4.7% relative humidity; n = 8/sex) or subjected to HS (39.4 ± 0.6°C; 33.7 ± 6.3% relative humidity) for 1 (HS1; n = 8/sex) or 7 days (HS7; n = 8/sex) followed by collection of the oxidative portion of the semitendinosus. Although HS increased muscle temperature, by 7 days, muscle from heat-stressed females was cooler than muscle from heat-stressed males (0.3°C; P < 0.05). Relative protein abundance of 4-hydroxynonenal (4-HNE)-modified proteins increased in HS1 females compared with TN (P = 0.05). Furthermore, malondialdehyde (MDA)-modified proteins and 8-hydroxy-2'-deoxyguanosine (8-OHdG) concentration, a DNA damage marker, was increased in HS7 females compared with TN females (P = 0.05). Enzymatic activities of catalase and superoxide dismutase (SOD) remained similar between groups; however, glutathione peroxidase (GPX) activity decreased in HS7 females compared with TN and HS1 females (P ≤ 0.03) and HS7 males (P = 0.02). Notably, HS increased skeletal muscle Ca2+ deposition (P = 0.05) and was greater in HS1 females compared with TN females (P < 0.05). Heat stress increased sarco(endo)plasmic reticulum Ca2+ ATPase (SERCA)2a protein abundance (P < 0.01); however, Ca2+ ATPase activity remained similar between groups. Overall, despite having lower muscle temperature, muscle from heat-stressed females had increased markers of oxidative stress and calcium deposition than muscle from males following identical environmental exposure.NEW & NOTEWORTHY Heat stress is a global threat to human health and agricultural production. We demonstrated that following 7 days of heat stress, skeletal muscle from females was more susceptible to oxidative stress than muscle from males in a porcine model, despite cooler muscle temperatures. The vulnerability to heat stress-induced oxidative stress in females may be driven, at least in part, by decreased antioxidant capacity and calcium dysregulation.
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Affiliation(s)
- Tori E Rudolph
- Department of Animal Science, Iowa State University, Ames, Iowa, United States
| | - Melissa Roths
- Department of Animal Science, Iowa State University, Ames, Iowa, United States
| | - Alyssa D Freestone
- Department of Animal Science, Iowa State University, Ames, Iowa, United States
| | - Sau Qwan Yap
- Department of Animal Science, Iowa State University, Ames, Iowa, United States
| | - Alyona Michael
- Department of Vet Diagnostic & Production Animal Med, Iowa State University, Ames, Iowa, United States
| | - Robert P Rhoads
- School of Animal Sciences, Virginia Tech, Blacksburg, Virginia, United States
| | - Sarah H White-Springer
- Department of Animal Science, Texas A&M University and Texas A&M AgriLife Research, College Station, Texas, United States
- Department of Kinesiology and Sport Management, Texas A&M University, College Station, Texas, United States
| | - Lance H Baumgard
- Department of Animal Science, Iowa State University, Ames, Iowa, United States
| | - Joshua T Selsby
- Department of Animal Science, Iowa State University, Ames, Iowa, United States
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3
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Protasi F, Girolami B, Roccabianca S, Rossi D. Store-operated calcium entry: From physiology to tubular aggregate myopathy. Curr Opin Pharmacol 2023; 68:102347. [PMID: 36608411 DOI: 10.1016/j.coph.2022.102347] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2022] [Revised: 11/30/2022] [Accepted: 12/04/2022] [Indexed: 01/06/2023]
Abstract
Store-Operated Ca2+ entry (SOCE) is recognized as a key mechanism in muscle physiology necessary to refill intracellular Ca2+ stores during sustained muscle activity. For many years the cell structures expected to mediate SOCE in skeletal muscle fibres remained unknown. Recently, the identification of Ca2+ Entry Units (CEUs) in exercised muscle fibres opened new insights into the role of extracellular Ca2+ in muscle contraction and, more generally, in intracellular Ca2+ homeostasis. Accordingly, intracellular Ca2+ unbalance due to alterations in SOCE strictly correlates with muscle disfunction and disease. Mutations in proteins involved in SOCE (STIM1, ORAI1, and CASQ1) have been linked to tubular aggregate myopathy (TAM), a disease that causes muscle weakness and myalgia and is characterized by a typical accumulation of highly ordered and packed membrane tubules originated from the sarcoplasmic reticulum (SR). Achieving a full understanding of the molecular pathways activated by alterations in Ca2+ entry mechanisms is a necessary step to design effective therapies for human SOCE-related disorders.
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Affiliation(s)
- Feliciano Protasi
- CAST, Center for Advanced Studies and Technology; University G. d'Annunzio of Chieti-Pescara, I-66100, Italy; DMSI, Department of Medicine and Aging Sciences; University G. d'Annunzio of Chieti-Pescara, I-66100, Italy
| | - Barbara Girolami
- CAST, Center for Advanced Studies and Technology; University G. d'Annunzio of Chieti-Pescara, I-66100, Italy; DMSI, Department of Medicine and Aging Sciences; University G. d'Annunzio of Chieti-Pescara, I-66100, Italy
| | - Sara Roccabianca
- DMMS, Department of Molecular and Developmental Medicine; University of Siena, I-53100, Siena Italy
| | - Daniela Rossi
- DMMS, Department of Molecular and Developmental Medicine; University of Siena, I-53100, Siena Italy.
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Dowling P, Gargan S, Swandulla D, Ohlendieck K. Proteomic profiling of impaired excitation-contraction coupling and abnormal calcium handling in muscular dystrophy. Proteomics 2022; 22:e2200003. [PMID: 35902360 PMCID: PMC10078611 DOI: 10.1002/pmic.202200003] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2022] [Revised: 07/19/2022] [Accepted: 07/25/2022] [Indexed: 11/06/2022]
Abstract
The X-linked inherited neuromuscular disorder Duchenne muscular dystrophy is characterised by primary abnormalities in the membrane cytoskeletal component dystrophin. The almost complete absence of the Dp427-M isoform of dystrophin in skeletal muscles renders contractile fibres more susceptible to progressive degeneration and a leaky sarcolemma membrane. This in turn results in abnormal calcium homeostasis, enhanced proteolysis and impaired excitation-contraction coupling. Biochemical and mass spectrometry-based proteomic studies of both patient biopsy specimens and genetic animal models of dystrophinopathy have demonstrated significant changes in the concentration and/or physiological function of essential calcium-regulatory proteins in dystrophin-lacking voluntary muscles. Abnormalities include dystrophinopathy-associated changes in voltage sensing receptors, calcium release channels, calcium pumps and calcium binding proteins. This review article provides an overview of the importance of the sarcolemmal dystrophin-glycoprotein complex and the wider dystrophin complexome in skeletal muscle and its linkage to depolarisation-induced calcium-release mechanisms and the excitation-contraction-relaxation cycle. Besides chronic inflammation, fat substitution and reactive myofibrosis, a major pathobiochemical hallmark of X-linked muscular dystrophy is represented by the chronic influx of calcium ions through the damaged plasmalemma in conjunction with abnormal intracellular calcium fluxes and buffering. Impaired calcium handling proteins should therefore be included in an improved biomarker signature of Duchenne muscular dystrophy.
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Affiliation(s)
- Paul Dowling
- Department of Biology, Maynooth University, National University of Ireland, Maynooth, Co. Kildare, Ireland.,Kathleen Lonsdale Institute for Human Health Research, Maynooth University, Maynooth, Co. Kildare, Ireland
| | - Stephen Gargan
- Department of Biology, Maynooth University, National University of Ireland, Maynooth, Co. Kildare, Ireland.,Kathleen Lonsdale Institute for Human Health Research, Maynooth University, Maynooth, Co. Kildare, Ireland
| | | | - Kay Ohlendieck
- Department of Biology, Maynooth University, National University of Ireland, Maynooth, Co. Kildare, Ireland.,Kathleen Lonsdale Institute for Human Health Research, Maynooth University, Maynooth, Co. Kildare, Ireland
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5
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Rodgers BD, Ward CW. Myostatin/Activin Receptor Ligands in Muscle and the Development Status of Attenuating Drugs. Endocr Rev 2022; 43:329-365. [PMID: 34520530 PMCID: PMC8905337 DOI: 10.1210/endrev/bnab030] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/24/2021] [Indexed: 02/07/2023]
Abstract
Muscle wasting disease indications are among the most debilitating and often deadly noncommunicable disease states. As a comorbidity, muscle wasting is associated with different neuromuscular diseases and myopathies, cancer, heart failure, chronic pulmonary and renal diseases, peripheral neuropathies, inflammatory disorders, and, of course, musculoskeletal injuries. Current treatment strategies are relatively ineffective and can at best only limit the rate of muscle degeneration. This includes nutritional supplementation and appetite stimulants as well as immunosuppressants capable of exacerbating muscle loss. Arguably, the most promising treatments in development attempt to disrupt myostatin and activin receptor signaling because these circulating factors are potent inhibitors of muscle growth and regulators of muscle progenitor cell differentiation. Indeed, several studies demonstrated the clinical potential of "inhibiting the inhibitors," increasing muscle cell protein synthesis, decreasing degradation, enhancing mitochondrial biogenesis, and preserving muscle function. Such changes can prevent muscle wasting in various disease animal models yet many drugs targeting this pathway failed during clinical trials, some from serious treatment-related adverse events and off-target interactions. More often, however, failures resulted from the inability to improve muscle function despite preserving muscle mass. Drugs still in development include antibodies and gene therapeutics, all with different targets and thus, safety, efficacy, and proposed use profiles. Each is unique in design and, if successful, could revolutionize the treatment of both acute and chronic muscle wasting. They could also be used in combination with other developing therapeutics for related muscle pathologies or even metabolic diseases.
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Affiliation(s)
| | - Christopher W Ward
- Department of Orthopedics and Center for Biomedical Engineering and Technology (BioMET), University of Maryland School of Medicine, Baltimore, MD, USA
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6
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Ohlendieck K, Swandulla D. Complexity of skeletal muscle degeneration: multi-systems pathophysiology and organ crosstalk in dystrophinopathy. Pflugers Arch 2021; 473:1813-1839. [PMID: 34553265 PMCID: PMC8599371 DOI: 10.1007/s00424-021-02623-1] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2021] [Revised: 09/07/2021] [Accepted: 09/08/2021] [Indexed: 02/07/2023]
Abstract
Duchenne muscular dystrophy is a highly progressive muscle wasting disorder due to primary abnormalities in one of the largest genes in the human genome, the DMD gene, which encodes various tissue-specific isoforms of the protein dystrophin. Although dystrophinopathies are classified as primary neuromuscular disorders, the body-wide abnormalities that are associated with this disorder and the occurrence of organ crosstalk suggest that a multi-systems pathophysiological view should be taken for a better overall understanding of the complex aetiology of X-linked muscular dystrophy. This article reviews the molecular and cellular effects of deficiency in dystrophin isoforms in relation to voluntary striated muscles, the cardio-respiratory system, the kidney, the liver, the gastrointestinal tract, the nervous system and the immune system. Based on the establishment of comprehensive biomarker signatures of X-linked muscular dystrophy using large-scale screening of both patient specimens and genetic animal models, this article also discusses the potential usefulness of novel disease markers for more inclusive approaches to differential diagnosis, prognosis and therapy monitoring that also take into account multi-systems aspects of dystrophinopathy. Current therapeutic approaches to combat muscular dystrophy are summarised.
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Affiliation(s)
- Kay Ohlendieck
- Department of Biology, Maynooth University, National University of Ireland, Co. Kildare, Maynooth, W23F2H6, Ireland.
- Kathleen Lonsdale Institute for Human Health Research, Maynooth University, Co. Kildare, Maynooth, W23F2H6, Ireland.
| | - Dieter Swandulla
- Institute of Physiology, University of Bonn, 53115, Bonn, Germany.
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7
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Romagnoli C, Sharma P, Zonefrati R, Palmini G, Lucattelli E, Ward DT, Ellinger I, Innocenti M, Brandi ML. Study of the Expression and Function of Calcium-Sensing Receptor in Human Skeletal Muscle. Int J Mol Sci 2021; 22:ijms22147282. [PMID: 34298895 PMCID: PMC8304165 DOI: 10.3390/ijms22147282] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2021] [Revised: 07/01/2021] [Accepted: 07/02/2021] [Indexed: 01/20/2023] Open
Abstract
Skeletal muscle has an outstanding capacity for regeneration in response to injuries, but there are disorders in which this process is seriously impaired, such as sarcopenia. Pharmacological treatments to restore muscle trophism are not available, therefore, the identification of suitable therapeutic targets that could be useful for the treatment of skeletal reduced myogenesis is highly desirable. In this in vitro study, we explored the expression and function of the calcium-sensing receptor (CaSR) in human skeletal muscle tissues and their derived satellite cells. The results obtained from analyses with various techniques of gene and protein CaSR expression and of its secondary messengers in response to calcium (Ca2+) and CaSR drugs have demonstrated that this receptor is not present in human skeletal muscle tissues, neither in the established satellite cells, nor during in vitro myogenic differentiation. Taken together, our data suggest that, although CaSR is a very important drug target in physiology and pathology, this receptor probably does not have any physiological role in skeletal muscle in normal conditions.
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Affiliation(s)
- Cecilia Romagnoli
- Department of Experimental and Clinical Biomedical Sciences, University of Florence, 50139 Florence, Italy; (C.R.); (P.S.); (R.Z.); (G.P.)
| | - Preeti Sharma
- Department of Experimental and Clinical Biomedical Sciences, University of Florence, 50139 Florence, Italy; (C.R.); (P.S.); (R.Z.); (G.P.)
| | - Roberto Zonefrati
- Department of Experimental and Clinical Biomedical Sciences, University of Florence, 50139 Florence, Italy; (C.R.); (P.S.); (R.Z.); (G.P.)
- Fondazione Italiana Ricerca sulla Malattie dell’Osso (FIRMO Onlus), 50141 Florence, Italy
| | - Gaia Palmini
- Department of Experimental and Clinical Biomedical Sciences, University of Florence, 50139 Florence, Italy; (C.R.); (P.S.); (R.Z.); (G.P.)
| | - Elena Lucattelli
- Plastic and Reconstructive Microsurgery, Careggi University Hospital, 50139 Florence, Italy; (E.L.); (M.I.)
| | - Donald T. Ward
- Faculty of Biology, Medicine and Health, The University of Manchester, Manchester M13 9PL, UK;
| | - Isabella Ellinger
- Institute for Pathophysiology and Allergy Research, Medical University of Vienna, 1090 Vienna, Austria;
| | - Marco Innocenti
- Plastic and Reconstructive Microsurgery, Careggi University Hospital, 50139 Florence, Italy; (E.L.); (M.I.)
| | - Maria Luisa Brandi
- Department of Experimental and Clinical Biomedical Sciences, University of Florence, 50139 Florence, Italy; (C.R.); (P.S.); (R.Z.); (G.P.)
- Fondazione Italiana Ricerca sulla Malattie dell’Osso (FIRMO Onlus), 50141 Florence, Italy
- Correspondence:
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8
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Downing K, Prisby R, Varanasi V, Zhou J, Pan Z, Brotto M. Old and new biomarkers for volumetric muscle loss. Curr Opin Pharmacol 2021; 59:61-69. [PMID: 34146835 DOI: 10.1016/j.coph.2021.05.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2021] [Revised: 05/04/2021] [Accepted: 05/05/2021] [Indexed: 12/21/2022]
Abstract
Volumetric muscle loss (VML) impacts skeletal muscles and causes damage to associated tissues such as blood vessels and other structural tissues. Despite progress in the VML field, current preclinical approaches are often ineffective at restoring muscle volume. Additional research is paramount to develop strategies that improve muscle mass and function, while restoring supporting tissues. We highlight mechanisms that govern normal muscle function that are also key players for VML, including intracellular calcium signaling/homeostasis, mitochondria signaling (calcium, reactiove oxidative species (ROS)/oxidative stress), and angiogenesis. We propose an integration of these processes within the context of emerging biomaterials that provide structural support for muscle regeneration. We posit that new biomarkers (i.e. myokines and lipid signaling mediators) may serve as sentinels of early muscle injury and regeneration. We conclude that as new ideas, approaches, and models come together, new treatments will emerge to allow the full rebuilding of skeletal muscles and functional recovery of skeletal muscles after VML.
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Affiliation(s)
- Kerrie Downing
- Bone-Muscle Collaborative Sciences, College of Nursing & Health Innovation, The University of Texas at Arlington, Arlington, TX 76010, USA
| | - Rhonda Prisby
- Bone-Muscle Collaborative Sciences, College of Nursing & Health Innovation, The University of Texas at Arlington, Arlington, TX 76010, USA
| | - Venu Varanasi
- Bone-Muscle Collaborative Sciences, College of Nursing & Health Innovation, The University of Texas at Arlington, Arlington, TX 76010, USA
| | - Jingsong Zhou
- Bone-Muscle Collaborative Sciences, College of Nursing & Health Innovation, The University of Texas at Arlington, Arlington, TX 76010, USA
| | - Zui Pan
- Bone-Muscle Collaborative Sciences, College of Nursing & Health Innovation, The University of Texas at Arlington, Arlington, TX 76010, USA.
| | - Marco Brotto
- Bone-Muscle Collaborative Sciences, College of Nursing & Health Innovation, The University of Texas at Arlington, Arlington, TX 76010, USA.
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9
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Alomar FA, Tian C, Dash PK, McMillan JM, Gendelman HE, Gorantla S, Bidasee KR. Efavirenz, atazanavir, and ritonavir disrupt sarcoplasmic reticulum Ca 2+ homeostasis in skeletal muscles. Antiviral Res 2021; 187:104975. [PMID: 33450312 DOI: 10.1016/j.antiviral.2020.104975] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Revised: 10/05/2020] [Accepted: 11/07/2020] [Indexed: 01/05/2023]
Abstract
While muscle fatigue, pain and weakness are common co-morbidities in HIV-1 infected people, their underlying cause remain poorly defined. To this end, we evaluated whether the common antiretroviral drugs efavirenz (EFV), atazanavir (ATV) and ritonavir (RTV) could be a contributing factor by pertubating sarcoplasmic reticulum (SR) Ca2+ cycling. In live-cell imaging, EFV (6.0 μM), ATV (6.0 μM), and RTV (3.0 μM) elicited Ca2+ transients and blebbing of the plasma membranes of C2C12 skeletal muscle myotubes. Pretreating C2C12 skeletal muscle myotubes with the SR Ca2+ release channel blocker ryanodine (50 μM), slowed the rate and amplitude of Ca2+ release from and reuptake of Ca2+ into the SR. EFV, ATV and RTV (1 nM - 20 μM) potentiated and then displaced [3H] ryanodine binding to rabbit skeletal muscle ryanodine receptor Ca2+ release channel (RyR1). These drugs at concentrations 0.25-31.2 μM also increased and or decreased the open probability of RyR1 by altering its gating and conductance. ATV (≤5 μM) potentiated and >5μM inhibited the ability of sarco (endo)plasmic reticulum Ca2+-ATPase (SERCA1) to hydrolyze ATP and transport Ca2+. RTV (2.5-31.5 μM) dose-dependently inhibited SERCA1-mediated, ATP-dependent Ca2+ transport. EFV (0.25-31.5 μM) had no measurable effect on SERCA1's ability to hydrolyze ATP and transport Ca2+. These data support the notion that EFV, ATV and RTV could be contributing to skeletal muscle co-morbidities in PLWH by modulating SR Ca2+ homeostasis.
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Affiliation(s)
- Fadhel A Alomar
- Department of Pharmacology and Toxicology, College of Clinical Pharmacy, Imam Abdulrahman Bin Faisal University, Dammam, 31441, Saudi Arabia
| | - Chengju Tian
- Departments of Pharmacology and Experimental Neuroscience, USA
| | - Prasanta K Dash
- Departments of Pharmacology and Experimental Neuroscience, USA
| | - JoEllyn M McMillan
- Departments of Pharmacology and Experimental Neuroscience, USA; Environment and Occupational Health, University of Nebraska Medical Center, Omaha, NE, 68198, USA
| | | | - Santhi Gorantla
- Departments of Pharmacology and Experimental Neuroscience, USA
| | - Keshore R Bidasee
- Departments of Pharmacology and Experimental Neuroscience, USA; Environment and Occupational Health, University of Nebraska Medical Center, Omaha, NE, 68198, USA; Nebraska Redox Biology Center, Lincoln, NE, USA.
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10
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Jaque-Fernandez F, Beaulant A, Berthier C, Monteiro L, Allard B, Casas M, Rieusset J, Jacquemond V. Preserved Ca 2+ handling and excitation-contraction coupling in muscle fibres from diet-induced obese mice. Diabetologia 2020; 63:2471-2481. [PMID: 32840676 DOI: 10.1007/s00125-020-05256-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Accepted: 07/06/2020] [Indexed: 02/07/2023]
Abstract
AIMS/HYPOTHESIS Disrupted intracellular Ca2+ handling is known to play a role in diabetic cardiomyopathy but it has also been postulated to contribute to obesity- and type 2 diabetes-associated skeletal muscle dysfunction. Still, there is so far very limited functional insight into whether, and if so to what extent, muscular Ca2+ homeostasis is affected in this situation, so as to potentially determine or contribute to muscle weakness. In differentiated muscle, force production is under the control of the excitation-contraction coupling process: upon plasma membrane electrical activity, the CaV1.1 voltage sensor/Ca2+ channel in the plasma membrane triggers opening of the ryanodine receptor Ca2+ release channel in the sarcoplasmic reticulum (SR) membrane. Opening of the ryanodine receptor triggers the rise in cytosolic Ca2+, which activates contraction while Ca2+ uptake by the SR ATPase Ca2+-pump promotes relaxation. These are the core mechanisms underlying the tight control of muscle force by neuronal electrical activity. This study aimed at characterising their inherent physiological function in a diet-induced mouse model of obesity and type 2 diabetes. METHODS Intact muscle fibres were isolated from mice fed either with a standard chow diet or with a high-fat, high-sucrose diet generating obesity, insulin resistance and glucose intolerance. Properties of muscle fibres were investigated with a combination of whole-cell voltage-clamp electrophysiology and confocal fluorescence imaging. The integrity and density of the plasma membrane network (transverse tubules) that carries the membrane excitation throughout the muscle fibres was assessed with the dye Di-8-ANEPPS. CaV1.1 Ca2+ channel activity was studied by measuring the changes in current across the plasma membrane elicited by voltage-clamp depolarising pulses of increasing amplitude. SR Ca2+ release through ryanodine receptors was simultaneously detected with the Ca2+-sensitive dye Rhod-2 in the cytosol. CaV1.1 voltage-sensing activity was separately characterised from the properties of intra-plasma-membrane charge movement produced by short voltage-clamp depolarising pulses. Spontaneous Ca2+ release at rest was assessed with the Ca2+-sensitive dye Fluo-4. The rate of SR Ca2+ uptake was assessed from the time course of cytosolic Ca2+ recovery after the end of voltage excitation using the Ca2+-sensitive dye Fluo-4FF. The response to a fatigue-stimulation protocol was determined from the time course of decline of the peak Fluo-4FF Ca2+ transients elicited by 30 trains of 5-ms-long depolarising pulses delivered at 100 Hz. RESULTS The transverse tubule network architecture and density were well preserved in the fibres from the obese mice. The CaV1.1 Ca2+ current and voltage-sensing properties were also largely unaffected with mean values for maximum conductance and maximum amount of charge of 234 ± 12 S/F and 30.7 ± 1.6 nC/μF compared with 196 ± 13 S/F and 32.9 ± 2.0 nC/μF in fibres from mice fed with the standard diet, respectively. Voltage-activated SR Ca2+ release through ryanodine receptors also exhibited very similar properties in the two groups with mean values for maximum rate of Ca2+ release of 76.0 ± 6.5 and 78.1 ± 4.4 μmol l-1 ms-1, in fibres from control and obese mice, respectively. The response to a fatigue protocol was also largely unaffected in fibres from the obese mice, and so were the rate of cytosolic Ca2+ removal and the spontaneous Ca2+ release activity at rest. CONCLUSIONS/INTERPRETATION The functional properties of the main mechanisms involved in the control of muscle Ca2+ homeostasis are well preserved in muscle fibres from obese mice, at the level of both the plasma membrane and of the SR. We conclude that intracellular Ca2+ handling and excitation-contraction coupling in skeletal muscle fibres are not primary targets of obesity and type 2 diabetes. Graphical abstract.
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Affiliation(s)
- Francisco Jaque-Fernandez
- Institut NeuroMyoGène, UMR CNRS 5310 - Inserm U1217 - Université Claude Bernard Lyon 1 - Univ Lyon, Faculté de Médecine et de Pharmacie, Lyon, France
| | - Agathe Beaulant
- CarMeN Laboratory, Inserm, INRA, INSA Lyon, Université Claude Bernard Lyon 1 - Univ Lyon, Pierre-Bénite, France
| | - Christine Berthier
- Institut NeuroMyoGène, UMR CNRS 5310 - Inserm U1217 - Université Claude Bernard Lyon 1 - Univ Lyon, Faculté de Médecine et de Pharmacie, Lyon, France
| | - Laloé Monteiro
- Institut NeuroMyoGène, UMR CNRS 5310 - Inserm U1217 - Université Claude Bernard Lyon 1 - Univ Lyon, Faculté de Médecine et de Pharmacie, Lyon, France
| | - Bruno Allard
- Institut NeuroMyoGène, UMR CNRS 5310 - Inserm U1217 - Université Claude Bernard Lyon 1 - Univ Lyon, Faculté de Médecine et de Pharmacie, Lyon, France
| | - Mariana Casas
- Programa de Fisiología y Biofísica, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, Santiago, Chile
| | - Jennifer Rieusset
- CarMeN Laboratory, Inserm, INRA, INSA Lyon, Université Claude Bernard Lyon 1 - Univ Lyon, Pierre-Bénite, France
| | - Vincent Jacquemond
- Institut NeuroMyoGène, UMR CNRS 5310 - Inserm U1217 - Université Claude Bernard Lyon 1 - Univ Lyon, Faculté de Médecine et de Pharmacie, Lyon, France.
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Ca 2+ Channels Mediate Bidirectional Signaling between Sarcolemma and Sarcoplasmic Reticulum in Muscle Cells. Cells 2019; 9:cells9010055. [PMID: 31878335 PMCID: PMC7016941 DOI: 10.3390/cells9010055] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2019] [Revised: 12/19/2019] [Accepted: 12/23/2019] [Indexed: 12/21/2022] Open
Abstract
The skeletal muscle and myocardial cells present highly specialized structures; for example, the close interaction between the sarcoplasmic reticulum (SR) and mitochondria—responsible for excitation-metabolism coupling—and the junction that connects the SR with T-tubules, critical for excitation-contraction (EC) coupling. The mechanisms that underlie EC coupling in these two cell types, however, are fundamentally distinct. They involve the differential expression of Ca2+ channel subtypes: CaV1.1 and RyR1 (skeletal), vs. CaV1.2 and RyR2 (cardiac). The CaV channels transform action potentials into elevations of cytosolic Ca2+, by activating RyRs and thus promoting SR Ca2+ release. The high levels of Ca2+, in turn, stimulate not only the contractile machinery but also the generation of mitochondrial reactive oxygen species (ROS). This forward signaling is reciprocally regulated by the following feedback mechanisms: Ca2+-dependent inactivation (of Ca2+ channels), the recruitment of Na+/Ca2+ exchanger activity, and oxidative changes in ion channels and transporters. Here, we summarize both well-established concepts and recent advances that have contributed to a better understanding of the molecular mechanisms involved in this bidirectional signaling.
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