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Hockerman GH, Pratt E, Guha S, LaVigne E, Whitmore C, Khader O, McClure N, Zampieri S, Koran J, Wang WH, Pond AL. ERG1A K + channel increases intracellular calcium concentration through modulation of calsequestrin1 in C 2C 12 myotubes. Sci Rep 2025; 15:9480. [PMID: 40108273 PMCID: PMC11923081 DOI: 10.1038/s41598-025-93788-7] [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: 11/19/2024] [Accepted: 03/10/2025] [Indexed: 03/22/2025] Open
Abstract
The ERG1A K+ channel modulates the protein degradation that contributes to skeletal muscle atrophy by increasing intracellular calcium concentration ([Ca2+]i) and enhancing calpain activity, but the mechanism by which the channel regulates the [Ca2+]i is not known. Here, we have investigated the effect of human ERG1A (HERG) on [Ca2+]i in C2C12 myotubes, using Fura-2 calcium assays, immunoblot, RT-qPCR, and electrophysiology. The data show that the rise in [Ca2+]i induced by KCl-stimulated depolarization is of greater amplitude in C2C12 myotubes over-expressing HERG relative to controls, but this difference does not result from an increase in L-type channel (Cav1.1) Ca2+ influx because there is no statistical difference in the nifedipine-sensitive response upon depolarization between the expression groups. Indeed, HERG overexpression in C2C12 myotubes has no effect on the amplitude of L-type channel current nor does it affect the mRNA levels nor protein abundance of the Cav1.1 channel. This finding suggests that HERG modulates excitation coupled calcium entry (ECCE). Indeed, the HERG-enhanced increase in [Ca2+]i induced by depolarization is blocked by 2-aminoethoxydiphenyl borate, an inhibitor of ECCE. Further, HERG also modulates the activity of ryanodine receptors (RYR1, a component of ECCE) as well as store operated calcium entry (SOCE). Therefore, we investigated the effect of HERG on calsequestrin1, a calcium buffering/binding protein known to modulate RYR1 and SOCE activities. Indeed, we find that calsequestrin1 mRNA levels are decreased 0.83-fold (p < 0.05) and the total protein abundance is lowered 77% (p < 0.05) in myotubes over-expressing HERG relative to controls. In conclusion, the data show that ERG1A overexpression modulates [Ca2+]i in skeletal muscle cells by lowering the abundance of the calcium buffering/binding protein calsequestrin1 which interacts with RyR1 and SOCE pathways. Indeed, we report that overexpression of HERG in myotubes increases [Ca2+]i by modulation of RyR1 as well as ECCE and SOCE activities. It is likely that HERG enhancement of RyR1 activity, through decreased Casq1 abundance, is increasing [Ca2+]i. This study provides a potential mechanism to explain how upregulation of ERG1A contributes to increased [Ca2+]i and, thus, atrophy in skeletal muscle.
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Affiliation(s)
- Gregory H Hockerman
- Medicinal Chemistry and Molecular Pharmacology Department, Purdue University School of Pharmacy, West Lafayette, IN, 47906, USA
| | - Evan Pratt
- Medicinal Chemistry and Molecular Pharmacology Department, Purdue University School of Pharmacy, West Lafayette, IN, 47906, USA
| | - Shalini Guha
- Anatomy Department, School of Medicine, Southern Illinois University, Life Sciences Building III, Room 2080, 1135 Lincoln Drive, Mail Code 6523, Carbondale, IL, 62902, USA
| | - Emily LaVigne
- Medicinal Chemistry and Molecular Pharmacology Department, Purdue University School of Pharmacy, West Lafayette, IN, 47906, USA
| | - Clayton Whitmore
- Anatomy Department, School of Medicine, Southern Illinois University, Life Sciences Building III, Room 2080, 1135 Lincoln Drive, Mail Code 6523, Carbondale, IL, 62902, USA
| | - Omar Khader
- Anatomy Department, School of Medicine, Southern Illinois University, Life Sciences Building III, Room 2080, 1135 Lincoln Drive, Mail Code 6523, Carbondale, IL, 62902, USA
| | - Natalie McClure
- Anatomy Department, School of Medicine, Southern Illinois University, Life Sciences Building III, Room 2080, 1135 Lincoln Drive, Mail Code 6523, Carbondale, IL, 62902, USA
| | - Sandra Zampieri
- Department of Surgery, Oncology and Gastroenterology, University of Padova, Padua, Italy
- Department of Biomedical Sciences, University of Padova, Padua, Italy
| | - Jennifer Koran
- School of Education, SIU Carbondale, Carbondale, IL, USA
| | - W-H Wang
- Genetic Editing Core Facility, Purdue University, West Lafayette, IN, USA
| | - Amber L Pond
- Anatomy Department, School of Medicine, Southern Illinois University, Life Sciences Building III, Room 2080, 1135 Lincoln Drive, Mail Code 6523, Carbondale, IL, 62902, USA.
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Liu Y, Cao X, Zhou Q, Deng C, Yang Y, Huang D, Luo H, Zhang S, Li Y, Xu J, Chen H. Mechanisms and Countermeasures for Muscle Atrophy in Microgravity. Cells 2024; 13:2120. [PMID: 39768210 PMCID: PMC11727360 DOI: 10.3390/cells13242120] [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: 10/29/2024] [Revised: 12/09/2024] [Accepted: 12/18/2024] [Indexed: 01/12/2025] Open
Abstract
Previous studies have revealed that muscle atrophy emerges as a significant challenge faced by astronauts during prolonged missions in space. A loss in muscle mass results in a weakening of skeletal muscle strength and function, which will not only contribute to a decline in overall physical performance but also elevate the risk of various age-related diseases. Skeletal muscle atrophy in the microgravity environment is thought to be associated with changes in energy metabolism, protein metabolism, calcium ion homeostasis, myostatin levels, and apoptosis. Modulating some pathways could be a promising approach to mitigating muscle atrophy in the microgravity environment. This review serves as a comprehensive summary of research on the impact of microgravity on skeletal muscle, with the aim of providing insights into its pathogenesis and the development of effective treatments.
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Affiliation(s)
- Yizhou Liu
- Department of Rehabilitation, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China; (Y.L.); (X.C.); (Q.Z.); (C.D.); (Y.Y.); (D.H.); (H.L.); (S.Z.); (Y.L.); (J.X.)
| | - Xiaojian Cao
- Department of Rehabilitation, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China; (Y.L.); (X.C.); (Q.Z.); (C.D.); (Y.Y.); (D.H.); (H.L.); (S.Z.); (Y.L.); (J.X.)
| | - Qiuzhi Zhou
- Department of Rehabilitation, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China; (Y.L.); (X.C.); (Q.Z.); (C.D.); (Y.Y.); (D.H.); (H.L.); (S.Z.); (Y.L.); (J.X.)
- Stem Cell Research Center, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Chunchu Deng
- Department of Rehabilitation, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China; (Y.L.); (X.C.); (Q.Z.); (C.D.); (Y.Y.); (D.H.); (H.L.); (S.Z.); (Y.L.); (J.X.)
| | - Yujie Yang
- Department of Rehabilitation, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China; (Y.L.); (X.C.); (Q.Z.); (C.D.); (Y.Y.); (D.H.); (H.L.); (S.Z.); (Y.L.); (J.X.)
| | - Danxia Huang
- Department of Rehabilitation, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China; (Y.L.); (X.C.); (Q.Z.); (C.D.); (Y.Y.); (D.H.); (H.L.); (S.Z.); (Y.L.); (J.X.)
| | - Hongmei Luo
- Department of Rehabilitation, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China; (Y.L.); (X.C.); (Q.Z.); (C.D.); (Y.Y.); (D.H.); (H.L.); (S.Z.); (Y.L.); (J.X.)
| | - Song Zhang
- Department of Rehabilitation, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China; (Y.L.); (X.C.); (Q.Z.); (C.D.); (Y.Y.); (D.H.); (H.L.); (S.Z.); (Y.L.); (J.X.)
| | - Yajie Li
- Department of Rehabilitation, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China; (Y.L.); (X.C.); (Q.Z.); (C.D.); (Y.Y.); (D.H.); (H.L.); (S.Z.); (Y.L.); (J.X.)
- Stem Cell Research Center, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Jia Xu
- Department of Rehabilitation, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China; (Y.L.); (X.C.); (Q.Z.); (C.D.); (Y.Y.); (D.H.); (H.L.); (S.Z.); (Y.L.); (J.X.)
- Stem Cell Research Center, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Hong Chen
- Department of Rehabilitation, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China; (Y.L.); (X.C.); (Q.Z.); (C.D.); (Y.Y.); (D.H.); (H.L.); (S.Z.); (Y.L.); (J.X.)
- Stem Cell Research Center, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
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Ravara B, Giuriati W, Zampieri S, Kern H, Pond AL. Translational mobility medicine and ugo carraro: a life of significant scientific contributions reviewed in celebration. Neurol Res 2024; 46:139-156. [PMID: 38043115 DOI: 10.1080/01616412.2023.2258041] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2022] [Accepted: 09/04/2023] [Indexed: 12/05/2023]
Abstract
Prof. Ugo Carraro reached 80 years of age on 23 February 2023, and we wish to celebrate him and his work by reviewing his lifetime of scientific achievements in Translational Myology. Currently, he is a Senior Scholar with the University of Padova, Italy, where, as a tenured faculty member, he founded the Interdepartmental Research Center of Myology. Prof. Carraro, a pioneer in skeletal muscle research, is a world-class expert in structural and molecular investigations of skeletal muscle biology, physiology, pathology, and care. An authority in bidimensional gel electrophoresis for myosin light chains, he was the first to separate mammalian muscle myosin heavy chain isoforms by SDS-gel electrophoresis. He has demonstrated that long-term denervated muscle can survive denervation by myofiber regeneration, and shown that an athletic lifestyle has beneficial impacts on muscle reinnervation. He has utilized his expertise in translational myology to develop and validate rehabilitative treatments for denervated and ageing skeletal muscle. He has authored more than 160 PubMed listed papers and numerous scholarly books, including his recent autobiography. Prof. Carraro founded and serves as Editor-in-Chief of the European Journal of Translational Myology and Mobility Medicine. He has organized more than 40 Padua Muscle Days Meetings and continues this, encouraging students and young scientists to participate. As he dreams endlessly, he is currently validating non-invasive analyses on saliva, a promising approach that will allow increased frequency sampling to analyze systemic factors during the transient effects of training and rehabilitation by his proposed Full-Body in- Bed Gym for bed-ridden elderly.
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Affiliation(s)
- Barbara Ravara
- Department of Biomedical Sciences (DSB), University of Padova, Padua, Italy
- CIR-Myo Interdepartmental Research Center of Myology, University of Padova, Padua, Italy
| | - Walter Giuriati
- Department of Biomedical Sciences (DSB), University of Padova, Padua, Italy
- CIR-Myo Interdepartmental Research Center of Myology, University of Padova, Padua, Italy
| | - Sandra Zampieri
- Department of Biomedical Sciences (DSB), University of Padova, Padua, Italy
- CIR-Myo Interdepartmental Research Center of Myology, University of Padova, Padua, Italy
- Department of Surgery, Oncology and Gastroenterology Sciences, Padua University Hospital, Padua, Italy
| | - Helmut Kern
- Physiko- und Rheumatherapie, Ludwig Boltzmann Institute for Rehabilitation Research, Sankt Pölten, Austria
| | - Amber L Pond
- Anatomy Department, Southern Illinois University School of Medicine, Carbondale, IL 62901, USA
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Juhl CR, Burgdorf J, Knudsen C, Lubberding AF, Veedfald S, Isaksen JL, Hartmann B, Frikke-Schmidt R, Mandrup-Poulsen T, Holst JJ, Kanters JK, Torekov SS. A randomized, double-blind, crossover study of the effect of the fluoroquinolone moxifloxacin on glucose levels and insulin sensitivity in young men and women. Diabetes Obes Metab 2023; 25:98-109. [PMID: 36054143 PMCID: PMC10087839 DOI: 10.1111/dom.14851] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/30/2022] [Revised: 08/15/2022] [Accepted: 08/22/2022] [Indexed: 12/14/2022]
Abstract
AIM The voltage-gated potassium channel Kv 11.1 is important for repolarizing the membrane potential in excitable cells such as myocytes, pancreatic α- and β-cells. Moxifloxacin blocks the Kv 11.1 channel and increases the risk of hypoglycaemia in patients with diabetes. We investigated glucose regulation and secretion of glucoregulatory hormones in young people with and without moxifloxacin, a drug known to block the Kv 11.1 channel. MATERIALS AND METHODS The effect of moxifloxacin (800 mg/day for 4 days) or placebo on glucose regulation was assessed in a randomized, double-blind, crossover study of young men and women (age 20-40 years and body mass index 18.5-27.5 kg/m2 ) without chronic disease, using 6-h oral glucose tolerance tests and continuous glucose monitoring. RESULTS Thirty-eight participants completed the study. Moxifloxacin prolonged the QTcF interval and increased heart rate. Hypoglycaemia was more frequently observed with moxifloxacin, both during the 8 days of continuous glucose monitoring and during the oral glucose tolerance tests. Hypoglycaemia questionnaire scores were higher after intake of moxifloxacin. Moxifloxacin reduced the early plasma-glucose response (AUC0-30 min ) by 7% (95% CI: -9% to -4%, p < .01), and overall insulin response (AUC0-360 min ) decreased by 18% (95% CI: -24% to -11%, p < .01) and plasma glucagon increased by 17% (95% CI: 4%-33%, p = .03). Insulin sensitivity calculated as the Matsuda index increased by 11%, and MISI, an index of muscle insulin sensitivity, increased by 34%. CONCLUSIONS In young men and women, moxifloxacin, a drug known to block the Kv 11.1 channel, increased QT interval, decreased glucose levels and was associated with increased muscle insulin sensitivity and more frequent episodes of hypoglycaemia.
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Affiliation(s)
- Christian R Juhl
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Josephine Burgdorf
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Cecilie Knudsen
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Anniek F Lubberding
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Simon Veedfald
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Jonas L Isaksen
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Bolette Hartmann
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Ruth Frikke-Schmidt
- Department of Clinical Biochemistry, Copenhagen University Hospital-Rigshospitalet, Copenhagen, Denmark
- Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Thomas Mandrup-Poulsen
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Jens J Holst
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Jørgen K Kanters
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Signe S Torekov
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
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