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Thammayon N, Wongdee K, Teerapornpuntakit J, Panmanee J, Chanpaisaeng K, Charoensetakul N, Srimongkolpithak N, Suntornsaratoon P, Charoenphandhu N. Enhancement of intestinal calcium transport by short-chain fatty acids: roles of Na +/H + exchanger 3 and transient receptor potential vanilloid subfamily 6. Am J Physiol Cell Physiol 2024; 326:C317-C330. [PMID: 38073487 DOI: 10.1152/ajpcell.00330.2023] [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: 07/21/2023] [Revised: 12/01/2023] [Accepted: 12/02/2023] [Indexed: 01/18/2024]
Abstract
Small organic molecules in the intestinal lumen, particularly short-chain fatty acids (SCFAs) and glucose, have long been postulated to enhance calcium absorption. Here, we used 45Ca radioactive tracer to determine calcium fluxes across the rat intestine after exposure to glucose and SCFAs. Confirming previous reports, glucose was found to increase the apical-to-basolateral calcium flux in the cecum. Under apical glucose-free conditions, SCFAs (e.g., butyrate) stimulated the cecal calcium fluxes by approximately twofold, while having no effect on proximal colon. Since SCFAs could be absorbed into the circulation, we further determined whether basolateral SCFA exposure rendered some positive actions. It was found that exposure of duodenum and cecum on the basolateral side to acetate or butyrate increased calcium fluxes. Under butyrate-rich conditions, cecal calcium transport was partially diminished by Na+/H+ exchanger 3 (NHE3) inhibitor (tenapanor) and nonselective transient receptor potential vanilloid subfamily 6 (TRPV6) inhibitor (miconazole). To confirm the contribution of TRPV6 to SCFA-stimulated calcium transport, we synthesized another TRPV6 inhibitor that was demonstrated by in silico molecular docking and molecular dynamics to occlude TRPV6 pore and diminish the glucose- and butyrate-induced calcium fluxes. Therefore, besides corroborating the importance of luminal molecules in calcium absorption, our findings provided foundation for development of more effective calcium-rich nutraceuticals in combination with various absorptive enhancers, e.g., glucose and SCFAs.NEW & NOTEWORTHY Organic molecules in the intestinal lumen, e.g., glucose and short-chain fatty acids (SCFAs), the latter of which are normally produced by microfloral fermentation, can stimulate calcium absorption dependent on transient receptor potential vanilloid subfamily 6 (TRPV6) and Na+/H+ exchanger 3 (NHE3). A selective TRPV6 inhibitor synthesized and demonstrated by in silico docking and molecular dynamics to specifically bind to the pore domain of TRPV6 was used to confirm a significant contribution of this channel. Our findings corroborate physiological significance of nutrients and SCFAs in enhancing calcium absorption.
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Affiliation(s)
- Nithipak Thammayon
- Center of Calcium and Bone Research (COCAB), Faculty of Science, Mahidol University, Bangkok, Thailand
- Department of Physiology, Faculty of Science, Mahidol University, Bangkok, Thailand
- Graduate Program in Molecular Medicine, Faculty of Science, Mahidol University, Bangkok, Thailand
| | - Kannikar Wongdee
- Center of Calcium and Bone Research (COCAB), Faculty of Science, Mahidol University, Bangkok, Thailand
- Faculty of Allied Health Sciences, Burapha University, Chonburi, Thailand
| | - Jarinthorn Teerapornpuntakit
- Center of Calcium and Bone Research (COCAB), Faculty of Science, Mahidol University, Bangkok, Thailand
- Department of Physiology, Faculty of Medical Science, Naresuan University, Phitsanulok, Thailand
| | - Jiraporn Panmanee
- Research Center for Neuroscience, Institute of Molecular Biosciences, Mahidol University, Nakhon Pathom, Thailand
| | - Krittikan Chanpaisaeng
- Center of Calcium and Bone Research (COCAB), Faculty of Science, Mahidol University, Bangkok, Thailand
- National Center for Genetic Engineering and Biotechnology (BIOTEC), National Science and Technology Development Agency, Pathum Thani, Thailand
| | - Netnapa Charoensetakul
- National Center for Genetic Engineering and Biotechnology (BIOTEC), National Science and Technology Development Agency, Pathum Thani, Thailand
| | - Nitipol Srimongkolpithak
- National Center for Genetic Engineering and Biotechnology (BIOTEC), National Science and Technology Development Agency, Pathum Thani, Thailand
| | - Panan Suntornsaratoon
- Center of Calcium and Bone Research (COCAB), Faculty of Science, Mahidol University, Bangkok, Thailand
- Department of Physiology, Faculty of Science, Mahidol University, Bangkok, Thailand
| | - Narattaphol Charoenphandhu
- Center of Calcium and Bone Research (COCAB), Faculty of Science, Mahidol University, Bangkok, Thailand
- Department of Physiology, Faculty of Science, Mahidol University, Bangkok, Thailand
- Institute of Molecular Biosciences, Mahidol University, Nakhon Pathom, Thailand
- The Academy of Science, The Royal Society of Thailand, Bangkok, Thailand
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2
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Costa ML, Jurberg AD, Mermelstein C. The Role of Embryonic Chick Muscle Cell Culture in the Study of Skeletal Myogenesis. Front Physiol 2021; 12:668600. [PMID: 34093232 PMCID: PMC8173222 DOI: 10.3389/fphys.2021.668600] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2021] [Accepted: 04/21/2021] [Indexed: 11/13/2022] Open
Abstract
The mechanisms involved in the development of skeletal muscle fibers have been studied in the last 70 years and yet many aspects of this process are still not completely understood. A myriad of in vivo and in vitro invertebrate and vertebrate animal models has been used for dissecting the molecular and cellular events involved in muscle formation. Among the most used animal models for the study of myogenesis are the rodents rat and mouse, the fruit fly Drosophila, and the birds chicken and quail. Here, we describe the robustness and advantages of the chick primary muscle culture model for the study of skeletal myogenesis. In the myoblast culture obtained from embryonic chick pectoralis muscle it is possible to analyze all the steps involved in skeletal myogenesis, such as myoblast proliferation, withdrawal from cell cycle, cell elongation and migration, myoblast alignment and fusion, the assembly of striated myofibrils, and the formation of multinucleated myotubes. The fact that in vitro chick myotubes can harbor hundreds of nuclei, whereas myotubes from cell lines have only a dozen nuclei demonstrates the high level of differentiation of the autonomous chick myogenic program. This striking differentiation is independent of serum withdrawal, which points to the power of the model. We also review the major pro-myogenic and anti-myogenic molecules and signaling pathways involved in chick myogenesis, in addition to providing a detailed protocol for the preparation of embryonic chick myogenic cultures. Moreover, we performed a bibliometric analysis of the articles that used this model to evaluate which were the main explored topics of interest and their contributors. We expect that by describing the major findings, and their advantages, of the studies using the embryonic chick myogenic model we will foster new studies on the molecular and cellular process involved in muscle proliferation and differentiation that are more similar to the actual in vivo condition than the muscle cell lines.
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Affiliation(s)
- Manoel L Costa
- Laboratório de Diferenciação Muscular, Instituto de Ciências Biomédicas, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Arnon D Jurberg
- Laboratório de Diferenciação Muscular, Instituto de Ciências Biomédicas, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil.,Faculdade de Medicina-Presidente Vargas, Universidade Estácio de Sá, Rio de Janeiro, Brazil
| | - Claudia Mermelstein
- Laboratório de Diferenciação Muscular, Instituto de Ciências Biomédicas, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
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Ortiz A, Gui J, Zahedi F, Yu P, Cho C, Bhattacharya S, Carbone CJ, Yu Q, Katlinski KV, Katlinskaya YV, Handa S, Haas V, Volk SW, Brice AK, Wals K, Matheson NJ, Antrobus R, Ludwig S, Whiteside TL, Sander C, Tarhini AA, Kirkwood JM, Lehner PJ, Guo W, Rui H, Minn AJ, Koumenis C, Diehl JA, Fuchs SY. An Interferon-Driven Oxysterol-Based Defense against Tumor-Derived Extracellular Vesicles. Cancer Cell 2019; 35:33-45.e6. [PMID: 30645975 PMCID: PMC6336114 DOI: 10.1016/j.ccell.2018.12.001] [Citation(s) in RCA: 117] [Impact Index Per Article: 23.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/19/2018] [Revised: 09/04/2018] [Accepted: 11/29/2018] [Indexed: 12/26/2022]
Abstract
Tumor-derived extracellular vesicles (TEV) "educate" healthy cells to promote metastases. We found that melanoma TEV downregulated type I interferon (IFN) receptor and expression of IFN-inducible cholesterol 25-hydroxylase (CH25H). CH25H produces 25-hydroxycholesterol, which inhibited TEV uptake. Low CH25H levels in leukocytes from melanoma patients correlated with poor prognosis. Mice incapable of downregulating the IFN receptor and Ch25h were resistant to TEV uptake, TEV-induced pre-metastatic niche, and melanoma lung metastases; however, ablation of Ch25h reversed these phenotypes. An anti-hypertensive drug, reserpine, suppressed TEV uptake and disrupted TEV-induced formation of the pre-metastatic niche and melanoma lung metastases. These results suggest the importance of CH25H in defense against education of normal cells by TEV and argue for the use of reserpine in adjuvant melanoma therapy.
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Affiliation(s)
- Angelica Ortiz
- Department of Biomedical Sciences, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Jun Gui
- Department of Biomedical Sciences, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Farima Zahedi
- Department of Biomedical Sciences, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Pengfei Yu
- Department of Biomedical Sciences, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Christina Cho
- Department of Biomedical Sciences, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Sabyasachi Bhattacharya
- Department of Biomedical Sciences, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Christopher J Carbone
- Department of Biomedical Sciences, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Qiujing Yu
- Department of Biomedical Sciences, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Kanstantsin V Katlinski
- Department of Biomedical Sciences, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Yuliya V Katlinskaya
- Department of Biomedical Sciences, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Simran Handa
- Department of Biomedical Sciences, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Victor Haas
- Department of Biomedical Sciences, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Susan W Volk
- Department of Clinical Sciences & Advanced Medicine, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Angela K Brice
- Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Kim Wals
- Department of Medicine, Cambridge Institute for Medical Research, Cambridge Biomedical Campus, Cambridge CB2 0XY, UK
| | - Nicholas J Matheson
- Department of Medicine, Cambridge Institute for Medical Research, Cambridge Biomedical Campus, Cambridge CB2 0XY, UK
| | - Robin Antrobus
- Department of Medicine, Cambridge Institute for Medical Research, Cambridge Biomedical Campus, Cambridge CB2 0XY, UK
| | - Sonja Ludwig
- Departments of Pathology, Immunology, and Otolaryngology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA; Department of Otorhinolaryngology, University of Duisburg-Essen, Duisburg, Germany
| | - Theresa L Whiteside
- Departments of Pathology, Immunology, and Otolaryngology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA
| | - Cindy Sander
- Department of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA
| | - Ahmad A Tarhini
- Department of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA
| | - John M Kirkwood
- Department of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA
| | - Paul J Lehner
- Department of Medicine, Cambridge Institute for Medical Research, Cambridge Biomedical Campus, Cambridge CB2 0XY, UK
| | - Wei Guo
- Department of Biology, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Hallgeir Rui
- Department of Pathology, Medical College of Wisconsin, Milwaukee, WI 53226, USA
| | - Andy J Minn
- Department of Radiation Oncology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Constantinos Koumenis
- Department of Radiation Oncology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - J Alan Diehl
- Department of Biochemistry, Hollings Cancer Center, Medical University of South Carolina, Charleston, SC 29425, USA
| | - Serge Y Fuchs
- Department of Biomedical Sciences, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.
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4
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McCammick EM, McVeigh P, McCusker P, Timson DJ, Morphew RM, Brophy PM, Marks NJ, Mousley A, Maule AG. Calmodulin disruption impacts growth and motility in juvenile liver fluke. Parasit Vectors 2016; 9:46. [PMID: 26817678 PMCID: PMC4730779 DOI: 10.1186/s13071-016-1324-9] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2015] [Accepted: 01/19/2016] [Indexed: 12/15/2022] Open
Abstract
Background Deficiencies in effective flukicide options and growing issues with drug resistance make current strategies for liver fluke control unsustainable, thereby promoting the need to identify and validate new control targets in Fasciola spp. parasites. Calmodulins (CaMs) are small calcium-sensing proteins with ubiquitous expression in all eukaryotic organisms and generally use fluctuations in intracellular calcium levels to modulate cell signalling events. CaMs are essential for fundamental processes including the phosphorylation of protein kinases, gene transcription, calcium transport and smooth muscle contraction. In the blood fluke Schistosoma mansoni, calmodulins have been implicated in egg hatching, miracidial transformation and larval development. Previously, CaMs have been identified amongst liver fluke excretory-secretory products and three CaM-like proteins have been characterised biochemically from adult Fasciola hepatica, although their functions remain unknown. Methods In this study, we set out to investigate the biological function and control target potential of F. hepatica CaMs (FhCaMs) using RNAi methodology alongside novel in vitro bioassays. Results Our results reveal that: (i) FhCaMs are widely expressed in parenchymal cells throughout the forebody region of juvenile fluke; (ii) significant transcriptional knockdown of FhCaM1-3 was inducible by exposure to either long (~200 nt) double stranded (ds) RNAs or 27 nt short interfering (si) RNAs, although siRNAs were less effective than long dsRNAs; (iii) transient long dsRNA exposure-induced RNA interference (RNAi) of FhCaMs triggered transcript knockdown that persisted for ≥ 21 days, and led to detectable suppression of FhCaM proteins; (iv) FhCaM RNAi significantly reduced the growth of juvenile flukes maintained in vitro; (v) FhCaM RNAi juveniles also displayed hyperactivity encompassing significantly increased migration; (vi) both the reduced growth and increased motility phenotypes were recapitulated in juvenile fluke using the CaM inhibitor trifluoperazine hydrochloride, supporting phenotype specificity. Conclusions These data indicate that the Ca2+-modulating functions of FhCaMs are important for juvenile fluke growth and movement and provide the first functional genomics-based example of a growth-defect resulting from gene silencing in liver fluke. Whilst the phenotypic impacts of FhCaM silencing on fluke behaviour do not strongly support their candidature as new flukicide targets, the growth impacts encourage further consideration, especially in light of the speed of juvenile fluke growth in vivo. Electronic supplementary material The online version of this article (doi:10.1186/s13071-016-1324-9) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Erin M McCammick
- Microbes & Pathogen Biology: Institute for Global Food Security, School of Biological Sciences, Queen's, University Belfast, Medical Biology Centre, 97 Lisburn Road, Belfast, BT9 7BL, UK.
| | - Paul McVeigh
- Microbes & Pathogen Biology: Institute for Global Food Security, School of Biological Sciences, Queen's, University Belfast, Medical Biology Centre, 97 Lisburn Road, Belfast, BT9 7BL, UK.
| | - Paul McCusker
- Microbes & Pathogen Biology: Institute for Global Food Security, School of Biological Sciences, Queen's, University Belfast, Medical Biology Centre, 97 Lisburn Road, Belfast, BT9 7BL, UK.
| | - David J Timson
- Microbes & Pathogen Biology: Institute for Global Food Security, School of Biological Sciences, Queen's, University Belfast, Medical Biology Centre, 97 Lisburn Road, Belfast, BT9 7BL, UK.
| | - Russell M Morphew
- Institute of Biological, Environmental and Rural Sciences, Aberystwyth University, Penglais, Aberystwyth, Ceredigion, SY23 3FL, UK.
| | - Peter M Brophy
- Institute of Biological, Environmental and Rural Sciences, Aberystwyth University, Penglais, Aberystwyth, Ceredigion, SY23 3FL, UK.
| | - Nikki J Marks
- Microbes & Pathogen Biology: Institute for Global Food Security, School of Biological Sciences, Queen's, University Belfast, Medical Biology Centre, 97 Lisburn Road, Belfast, BT9 7BL, UK.
| | - Angela Mousley
- Microbes & Pathogen Biology: Institute for Global Food Security, School of Biological Sciences, Queen's, University Belfast, Medical Biology Centre, 97 Lisburn Road, Belfast, BT9 7BL, UK.
| | - Aaron G Maule
- Microbes & Pathogen Biology: Institute for Global Food Security, School of Biological Sciences, Queen's, University Belfast, Medical Biology Centre, 97 Lisburn Road, Belfast, BT9 7BL, UK.
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5
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Identifying New Candidate Genes and Chemicals Related to Prostate Cancer Using a Hybrid Network and Shortest Path Approach. COMPUTATIONAL AND MATHEMATICAL METHODS IN MEDICINE 2015; 2015:462363. [PMID: 26504486 PMCID: PMC4609422 DOI: 10.1155/2015/462363] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/24/2015] [Accepted: 02/24/2015] [Indexed: 12/26/2022]
Abstract
Prostate cancer is a type of cancer that occurs in the male prostate, a gland in the male reproductive system. Because prostate cancer cells may spread to other parts of the body and can influence human reproduction, understanding the mechanisms underlying this disease is critical for designing effective treatments. The identification of as many genes and chemicals related to prostate cancer as possible will enhance our understanding of this disease. In this study, we proposed a computational method to identify new candidate genes and chemicals based on currently known genes and chemicals related to prostate cancer by applying a shortest path approach in a hybrid network. The hybrid network was constructed according to information concerning chemical-chemical interactions, chemical-protein interactions, and protein-protein interactions. Many of the obtained genes and chemicals are associated with prostate cancer.
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Horsley V, Pavlath GK. Forming a multinucleated cell: molecules that regulate myoblast fusion. Cells Tissues Organs 2004; 176:67-78. [PMID: 14745236 DOI: 10.1159/000075028] [Citation(s) in RCA: 181] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
In mammals, cell fusion occurs among a limited number of cell types: sperm and oocytes during fertilization, trophoblasts during placenta formation, macrophages during giant cell and osteoclast formation and myoblasts in the formation of myofibers and myotubes. The molecular mechanisms involved in these membrane fusion events largely are unknown. This review will focus on the known molecules that regulate myoblast fusion with an emphasis on a novel signaling pathway involving the calcium-regulated transcription factor NFATC2 in the regulation of myoblast fusion.
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Affiliation(s)
- Valerie Horsley
- Department of Pharmacology, Emory University, Atlanta, Ga., USA.
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7
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Mejia-Luna L, Avila G. Ca2+ channel regulation by transforming growth factor-beta 1 and bone morphogenetic protein-2 in developing mice myotubes. J Physiol 2004; 559:41-54. [PMID: 15218061 PMCID: PMC1665083 DOI: 10.1113/jphysiol.2004.066852] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
In skeletal muscle myogenesis, precursor cells or myoblasts fuse to form multinucleated cells (myotubes), which then further develop into functional muscle. We investigated if the inhibition of myogenesis by transforming growth factor-beta1 (TGF-beta1) and bone morphogenetic protein-2 (BMP-2) involve regulation of voltage-dependent Ca(2+) channels. Primary cultured myoblasts were kept in fusion medium (0-6 days) in either the absence (control conditions) or the presence of 40 pm TGF-beta1 or 5 nm BMP-2. Subsequently, the developing myotubes were transferred to a growth factor-free recording solution, and subjected to whole cell patch-clamp experiments. At day 0, 14% of non-fusing myoblasts exhibited T-current, whereas the L-current was practically absent. Under control conditions, however, the percentage of T- and L-channel-expressing myotubes increased sharply, from 25% at day 1 to approximately 100% at days 2-6. In addition, parallel increases were determined for Ca(2+)-currents density and cell membrane capacitance (C(m)), which is proportional to the size of myotubes. Interestingly, at days 1-2 TGF-beta1 and BMP-2 eliminated the T-current on initial 14% of T-channel-expressing myoblasts. Moreover, at day 6 the growth factors significantly reduced the maximal values of both T-current density (80%) and C(m) (60%). The effect of BMP-2 was selective on T-channels, whereas TGF-beta1 decreased also the L-current density (90%). A similar reduction in maximal conductance of the Ca(2+) channels was determined, in the absence of significant alterations in other essential properties of the channels, including the time course and voltage dependence of activation and inactivation. The results suggest these growth factors markedly reduce the number of functional T- (both TGF-beta1 and BMP-2) and L-channels (only TGF-beta1) in the surface of the plasma membrane, and contribute to explaining the associated effects on myogenesis.
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Affiliation(s)
- Lizbeth Mejia-Luna
- Department of Biochemistry, Cinvestav-IPN, AP 14-740, Mexico City, DF 07000, Mexico
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8
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Abmayr SM, Balagopalan L, Galletta BJ, Hong SJ. Cell and molecular biology of myoblast fusion. INTERNATIONAL REVIEW OF CYTOLOGY 2003; 225:33-89. [PMID: 12696590 DOI: 10.1016/s0074-7696(05)25002-7] [Citation(s) in RCA: 59] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
In organisms from Drosophila to mammals, the musculature is comprised of an elaborate array of distinct fibers that are generated by the fusion of committed myoblasts. These muscle fibers differ from each other in features that include location, pattern of innervation, site of attachment, and size. The sizes of the newly formed muscles of an embryo are controlled in large part by the number of cells that form the syncitial fiber. Over the past few decades, an extensive body of literature has described the process of myoblast fusion in vertebrates, relying primarily on the strengths of tissue culture model systems. More recently, genetic studies in Drosophila embryos have provided new insights into the process. Together, these studies define the steps necessary for myoblast differentiation, the acquisition of fusion competence, the recognition and adhesion between myoblasts, and the fusion of two lipid bilayers into one. In this review, we have attempted to combine insights from both Drosophila and vertebrate studies to trace the processes and molecules involved in myoblast fusion. Implicit in this approach is the assumption that fundamental aspects of myoblast fusion will be similar, independent of the organism in which it is occurring.
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MESH Headings
- Animals
- Cell Adhesion/physiology
- Cell Differentiation/physiology
- Cell Membrane/metabolism
- Drosophila melanogaster/embryology
- Drosophila melanogaster/metabolism
- Drosophila melanogaster/ultrastructure
- Embryo, Nonmammalian/embryology
- Embryo, Nonmammalian/metabolism
- Embryo, Nonmammalian/ultrastructure
- Humans
- Membrane Fusion/physiology
- Muscle Fibers, Skeletal/metabolism
- Muscle Fibers, Skeletal/ultrastructure
- Muscle, Skeletal/embryology
- Muscle, Skeletal/metabolism
- Muscle, Skeletal/ultrastructure
- Myoblasts, Skeletal/metabolism
- Myoblasts, Skeletal/ultrastructure
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Affiliation(s)
- Susan M Abmayr
- Department of Biochemistry and Molecular Biology, Pennsylvania State University, University Park, Pennsylvania 16802, USA
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9
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Toogood PL. Inhibition of protein-protein association by small molecules: approaches and progress. J Med Chem 2002; 45:1543-58. [PMID: 11931608 DOI: 10.1021/jm010468s] [Citation(s) in RCA: 221] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Peter L Toogood
- Department of Medicinal Chemistry, Pfizer Global Research and Development, 2800 Plymouth Road, Ann Arbor, Michigan 48105, USA.
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10
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Friday BB, Horsley V, Pavlath GK. Calcineurin activity is required for the initiation of skeletal muscle differentiation. J Cell Biol 2000; 149:657-66. [PMID: 10791979 PMCID: PMC2174840 DOI: 10.1083/jcb.149.3.657] [Citation(s) in RCA: 194] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Differentiation of skeletal muscle myoblasts follows an ordered sequence of events: commitment, cell cycle withdrawal, phenotypic differentiation, and finally cell fusion to form multinucleated myotubes. The molecular signaling pathways that regulate the progression are not well understood. Here we investigate the potential role of calcium and the calcium-dependent phosphatase calcineurin in myogenesis. Commitment, phenotypic differentiation, and cell fusion are identified as distinct calcium-regulated steps, based on the extracellular calcium concentration required for the expression of morphological and biochemical markers specific to each of these stages. Furthermore, differentiation is inhibited at the commitment stage by either treatment with the calcineurin inhibitor cyclosporine A (CSA) or expression of CAIN, a physiological inhibitor of calcineurin. Retroviral-mediated gene transfer of a constitutively active form of calcineurin is able to induce myogenesis only in the presence of extracellular calcium, suggesting that multiple calcium-dependent pathways are required for differentiation. The mechanism by which calcineurin initiates differentiation includes transcriptional activation of myogenin, but does not require the participation of NFAT. We conclude that commitment of skeletal muscle cells to differentiation is calcium and calcineurin-dependent, but NFAT-independent.
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Affiliation(s)
- Bret B. Friday
- Department of Pharmacology, Emory University School of Medicine, Atlanta, Georgia 30322
| | - Valerie Horsley
- Department of Pharmacology, Emory University School of Medicine, Atlanta, Georgia 30322
| | - Grace K. Pavlath
- Department of Pharmacology, Emory University School of Medicine, Atlanta, Georgia 30322
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11
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Temm-Grove CJ, Wert D, Thompson VF, Allen RE, Goll DE. Microinjection of calpastatin inhibits fusion in myoblasts. Exp Cell Res 1999; 247:293-303. [PMID: 10047471 DOI: 10.1006/excr.1998.4362] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Rat satellite cells (RSC) were microinjected with purified calpastatin or m-calpain, and myoblasts from a C2C12 mouse line were microinjected with purified calpastatin. Microinjection with calpastatin completely prevented fusion of myoblasts from both sources, whereas microinjection with m-calpain significantly increased the rate of fusion of cultured RSC; 44% of the nuclei of RSC cultures were in multinucleated myotubes within 48 h after microinjection with m-calpain plus labeled dextran, whereas only 15% of the nuclei were in multinucleated myotubes after microinjection with dextran alone. Western analyses indicated that neither RSC nor C2C12 myoblasts contained detectable amounts of mu-calpain before fusion. The levels of calpastatin in C2C12 myoblasts increased as cells passed from the proliferative stage to the onset of fusion, and these levels increased substantially in both the C2C12 and the RSC cells as they progressed to the late or postfusion stage. Both RSC and C2C12 myoblasts contained an 80-kDa polypeptide that was labeled with an anti-m-calpain antibody in Western blots. The results are consistent with a role of the calpain system (m-calpain in these myoblast lines) in remodeling of the cytoskeletal/plasma membrane interactions during cell fusion.
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Affiliation(s)
- C J Temm-Grove
- Muscle Biology Group, University of Arizona, Tucson, Arizona, 85721, USA
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12
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Wells C, Coles D, Entwistle A, Peckham M. Myogenic cells express multiple myosin isoforms. J Muscle Res Cell Motil 1997; 18:501-15. [PMID: 9350004 DOI: 10.1023/a:1018607100730] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
In vivo and in vitro, proliferating motile myoblasts form aligned groups of cells, with a characteristic bipolar morphology, subsequently become post-mitotic, begin to express skeletal myosin and fuse. We were interested in whether members of the myosin superfamily were involved in myogenesis. We found that the myoblasts expressed multiple myosin isoforms, from at least five different classes of the myosin superfamily (classes I, II, V, VII and IX), using RT-PCR and degenerate primers to conserved regions of myosin. All of these myosin isoforms were expressed most highly in myoblasts and their expression decreased as they differentiated into mature myotubes, by RNAse protection assays, and Western analysis. However, only myosin I alpha, non-muscle myosin IIA and IIB together with actin relocalize in response to the differentiative state of the cell. In single cells, myosin I alpha was found at the leading edge, in rear microspikes and had a punctate cytoplasmic staining, and non-muscle myosin was associated with actin bundles as previously described for fibroblasts. In aligned groups of cells, all these proteins were found at the plasma membrane. Co-staining for skeletal myosin II, and myosin I alpha showed that myosin I alpha also appeared to be expressed at higher levels in post-mitotic myoblasts that had begun to express skeletal myosin prior to fusion. In early myotubes, actin and non-muscle myosin IIA and IIB remained localized at the membrane. All of the other myosin isoforms we looked at, myosin V, myosin IX and a second isoform of myosin I (mouse homologue to myr2) showed a punctate cytoplasmic staining which did not change as the myoblasts differentiated. In conclusion, although we found that myoblasts express many different isoforms of the myosin superfamily, only myosin I alpha, non-muscle myosin IIA and IIB appear to play any direct role in myogenesis.
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Affiliation(s)
- C Wells
- Molecular Biology and Biophysics Group, Randall Institute, King's College London, UK
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13
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Doberstein SK, Fetter RD, Mehta AY, Goodman CS. Genetic analysis of myoblast fusion: blown fuse is required for progression beyond the prefusion complex. J Cell Biol 1997; 136:1249-61. [PMID: 9087441 PMCID: PMC2132517 DOI: 10.1083/jcb.136.6.1249] [Citation(s) in RCA: 174] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
The events of myoblast fusion in Drosophila are dissected here by combining genetic analysis with light and electron microscopy. We describe a new and essential intermediate step in the process, the formation of a prefusion complex consisting of "paired vesicles." These pairs of vesicles from different cells align with each other across apposed plasma membranes. This prefusion complex resolves into dense membrane plaques between apposed cells; these cells then establish cytoplasmic continuity by fusion of small areas of plasma membrane followed by vesiculation of apposed membranes. Different steps in this process are specifically blocked by mutations in four genes required for myoblast fusion. One of these genes, blown fuse, encodes a novel cytoplasmic protein expressed in unfused myoblasts that is essential for progression beyond the prefusion complex stage.
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Affiliation(s)
- S K Doberstein
- Department of Molecular and Cell Biology, University of California, Berkeley 94720, USA
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14
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Hernández EO, Trejo R, Espinosa AM, González A, Mújica A. Calmodulin binding proteins in the membrane vesicles released during the acrosome reaction and in the perinuclear material in isolated acrosome reacted sperm heads. Tissue Cell 1994; 26:849-65. [PMID: 7886673 DOI: 10.1016/0040-8166(94)90036-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Calmodulin has been suggested as the Ca(2+)-mediator in diverse cellular functions via its interaction with a number of proteins in a calcium-dependent manner. Its participation in the acrosome reaction has been suggested based on its localization in the acrosome region, on the effects produced by calmodulin antagonists, and by the changes in calmodulin compartmentation observed to occur throughout guinea pig acrosome reaction. To define the role of calmodulin in the membrane fusion events that occur during the acrosome reaction, the identification of calmodulin-binding proteins, by the overlay technique with biotinylated or unmodified calmodulin, was made in the following sperm fractions: in the membrane vesicles released during the acrosome reaction, in the remaining perinuclear material of acrosome reacted sperm heads and in a total membrane fraction from intact spermatozoa. The membrane vesicles released after the acrosome reaction showed four major calmodulin-binding proteins, M(r)s 66, 95, 97 and 110 kDa. The perinuclear material showed a 31-34, 43 and 97 kDa calmodulin-binding polypeptides. The membrane fraction from intact sperm showed eleven calmodulin-binding proteins, M(r)s between 14-110 kDa. Most of the binding proteins detected by this method corresponded to the class of calcium-independent calmodulin-binding proteins but proteins which only interacted with calmodulin in a calcium-inhibited mode were also observed. No calcium-dependent calmodulin-binding proteins were detected in any of the fractions studied. A possible role of these binding proteins in calmodulin compartmentation is discussed. The potential role of these binding proteins in membrane fusion and in membrane receptor localization in the postacrosomal region remain to be defined.
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Affiliation(s)
- E O Hernández
- Departamento de Biología Celular, Instituto Politécnico Nacional, México, D.F. México
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15
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Klöppel K, Gerlach J, Neuhaus P. [The electrolyte composition of liver preservation solutions for hepatocytes in a model of in vitro preservation and reoxygenation]. LANGENBECKS ARCHIV FUR CHIRURGIE 1994; 379:210-7. [PMID: 7934578 DOI: 10.1007/bf00186360] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The cation and anion content in liver preservation solutions have been investigated in order to justify the use of "intracellular" or "extracellular" electrolyte compositions. Various concentrations of sodium and potassium with chloride or lactobionate as anions and with added calcium and/or magnesium were made up as preservation solutions and incubated with in vitro adherent cultures of pig hepatocytes. In vitro hypoxia and hypothermia (4 degrees C, PO2 < 0.1 mmHg) for 24 h, with reoxygenation for 3 h, in standard culture medium was used as a model for preservation. Measurements of cell viability and detachment rate by light microscopy and of LDH and GOT liberation were used as parameters of cell damage. Cell swelling was estimated in suspension cultures of isolated hepatocytes. When chloride was used as the anion, significant cell toxicity from potassium concentrations over 75 mM was found within 6 h of preservation. Enzyme liberation decreased with increasing content of sodium cations in the preservation solution. Calcium ions had a protective effect at a concentration of 0.8 mM. Addition of magnesium to an "intracellular" ion composition minimized the toxic effect of potassium cations. Using lactobionate as an impermeant anion, there was no difference between the sodium and the potassium salt and the choice of cation had no effect on enzyme leakage or cell volume. An "extracellular" solution with high sodium chloride content and 0.8 mM calcium resulted in better preservation than was obtained with lactobionate solutions. With chloride as the anion, a significant increase in cell swelling was found when potassium replaced sodium in the solutions. Cell swelling decreased with increasing concentration of sodium cations.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- K Klöppel
- Chirurgische Klinik und Poliklinik, Universitätsklinikum Rudolf Virchow, Freie Universität, Berlin
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16
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Kim HS, Lee IH, Chung CH, Kang MS, Ha DB. Ca2+/calmodulin-dependent phosphorylation of the 100-kDa protein in chick embryonic muscle cells in culture. Dev Biol 1992; 150:223-30. [PMID: 1312962 DOI: 10.1016/0012-1606(92)90237-b] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The pattern of protein phosphorylation was found to change in differentiating chick embryonic myoblasts in culture. The extent of phosphorylation of 42-, 50-, and 100-kDa proteins increased while that of a 63-kDa protein declined in extracts of myoblasts that had been cultured for increasing periods. Of these, the increase in phosphorylation of the 100-kDa protein occurred most dramatically in extracts of myoblasts in an early stage of differentiation and was specifically inhibited by trifluoperazine (TFP) and other calmodulin (CaM) antagonists including chlorpromazine and N-(6-aminohexyl)-5-chloro-1-naphthalene-sulfonamide (W-7). Treatment of increasing concentrations of TFP to culture medium also decreased the phosphorylation state of the 100-kDa protein and the degree of myoblast fusion in parallel. In addition, levels of both the kinase activity and the 100-kDa protein but not of CaM appeared to rise in the cells cultured for longer periods. These results suggest that (1) a Ca2+/CaM-dependent protein kinase is responsible for phosphorylation of the 100-kDa protein, (2) the TFP-mediated myoblast fusion block may be associated with the inhibitory effect of the drug against the kinase activity, and (3) the increase in phosphorylation state of the 100-kDa protein during myogenic differentiation is due to the rise in levels of the kinase and its substrate.
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Affiliation(s)
- H S Kim
- Department of Molecular Biology, College of Natural Sciences, Seoul National University, Korea
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17
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Abstract
The involvement of Ca2+ and PGE1 in myoblast fusion has been well documented. Extracellular Ca2+ is essential for myoblast adhesion, alignment, and fusion. There is an obligatory increase in Ca2+ influx immediately preceding fusion and the Ca2+ ionophore A23187 promotes precocious fusion. PGE1 receptors appear just prior to fusion, and an antagonist of PGE1 binding to cell surface receptors blocks fusion when added prior to Ca2+ influx. Finally, exogenous PGE1 induces precocious fusion. The present study was an initial test of the hypothesis that membrane protein phosphorylation by protein kinase C (PKC) links PGE1 receptor occupancy and the increase in Ca2+ influx. Our conclusion that PKC is an essential component in the regulation of myoblast fusion is based in part on the following evidence: (1) an activator of PKC, the tumor promoter 12-O-tetradecanoylphorbol-13-acetate (TPA), at low concentration and for a brief exposure period, induces precocious fusion and stimulates Ca2+ influx; (2) 4 alpha-phorbol-12,13-didecanoate, an inactive analog of TPA, has no discernible effect on fusion or Ca2+ influx; (3) 1-oleoyl-2-acetyl glycerol, an analog of endogenous diacylglycerol (DAG) which activates PKC, promotes precocious fusion, as does the DAG kinase inhibitor R59022 (6-[2-[4-[(4-fluorophenyl)phenylmethylene]-1-piperidinyl]ethyl]-7- methyl-5H-thiazole-[3,2 alpha]-pyrimidin-5-one) which raises the level of endogenous DAG by inhibiting its catabolism; (4) 1-(5-isoquinolinesulfonyl)-2-methylpiperazine (H-7), a highly potent PKC inhibitor, reversibly blocks myogenesis at a point between alignment and fusion; and (5) H-7 also blocks the normal increase in Ca2+ influx preceding fusion.
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Affiliation(s)
- J D David
- Division of Biological Sciences, University of Missouri, Columbia 65211
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18
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Malvoisin E, Wild F. Effect of drugs which inhibit cholesterol synthesis on syncytia formation in vero cells infected with measles virus. BIOCHIMICA ET BIOPHYSICA ACTA 1990; 1042:359-64. [PMID: 2306487 DOI: 10.1016/0005-2760(90)90165-t] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
We found that nontoxic doses of two inhibitors of cholesterol synthesis, namely W-7 and cerulenin, delayed syncytia formation in vero cells infected with measles virus. To correlate syncytia formation and lipidic membrane changes induced by these drugs, we labelled cell lipids with [14C]acetate. Measles virus infection increased the incorporation of radiolabel into fatty acids, triacylglycerol, cholesterol ester, and decreased its incorporation into cholesterol and 1,2-diacylglycerol. The ratios phosphatidylcholine/sphingomyelin and free cholesterol/lanosterol-dihydrolanosterol also decreased during the infection. W-7 and cerulenin greatly altered lipid metabolism. Both decreased the phosphatidylcholine to sphingomyelin and the cholesterol to lanosterol-dihydrolanosterol ratios. Z-D-Phe-L-Phe-L-Gly, a tripeptide which corresponds to the N-terminal sequence of the viral fusion protein (responsible for syncytia formation) and which inhibits virus-induced cell fusion without affecting virus synthesis also perturbed cholesterol metabolism. The tripeptide reversed the phosphatidylcholine to sphingomyelin ratio in infected cells. At non-toxic doses, W-7 inhibited the synthesis of infectious virus. Cerulenin which inhibited strongly the lipid synthesis did not. Finally, the well characterized inhibitors of cholesterol synthesis, mevinolin, ketoconazole and miconazole were shown to inhibit the syncytia formation. We conclude that the inhibition of syncytia by W-7 and cerulenin is associated with their capacity to alter the cholesterol metabolism, whereas the antiviral effect of W-7 does not seem related to this capacity.
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Affiliation(s)
- E Malvoisin
- Laboratoire d'Immunovirologie Moléculaire et Cellulaire, Faculté de Médicine Alexis Carrel, Lyon, France
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19
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Rapuano M, Ross AF, Prives J. Opposing effects of calcium entry and phorbol esters on fusion of chick muscle cells. Dev Biol 1989; 134:271-8. [PMID: 2472983 DOI: 10.1016/0012-1606(89)90099-7] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Studies utilizing cultured muscle cells have shown that myoblast fusion requires extracellular Ca2+ and involves transient coordinated changes in cell membrane topography and cytoskeletal organization. However, neither the mechanisms by which Ca2+ influences these changes nor its cellular sites of action are known. We have investigated the effects of Ca2+ channel modulators and phorbol esters on fusion of embryonic chick myoblasts in culture. Myoblast fusion was inhibited by the Ca2+ channel blockers D600 and nitrendipine and stimulated by the Ca2+ channel activator Bay K 8644. We have obtained evidence that the tumor promoting phorbol ester 12-O-tetradecanoylphorbol-13-acetate (TPA) inhibits fusion through activation of protein kinase C. Myoblasts prevented from fusing by Ca2+ channel blockers or TPA display a distinctive elongated morphology that is characteristic of cells prevented from fusion by Ca2+ deprivation. The inhibition of fusion by D600 and TPA is significantly diminished in the presence of the Ca2+ ionophore A23187. TPA arrest of myoblast fusion was found to be accompanied by an increase in phosphorylation of the 20-kDa light chain of cytoplasmic myosin in a dose- and time-dependent manner. The effects of TPA on myoblast fusion and phosphorylation of myosin light chain were mimicked by the cell permeant diacylglycerol sn-1,2-dioctanoylglycerol, a potent activator of protein kinase C. The present results suggest that activators of protein kinase C block fusion by interfering with a Ca2+ signal transduction pathway and that this interference may be associated with a protein kinase C catalyzed inhibitory phosphorylation of myosin light chain.
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Affiliation(s)
- M Rapuano
- Cellular and Developmental Biology Program, State University of New York, Stony Brook 11794
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20
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Aitken RJ, Clarkson JS, Hulme MJ, Henderson CJ. Analysis of calmodulin acceptor proteins and the influence of calmodulin antagonists on human spermatozoa. GAMETE RESEARCH 1988; 21:93-111. [PMID: 2852636 DOI: 10.1002/mrd.1120210111] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
The possible role of calmodulin in regulating a number of calcium-dependent functions exhibited by human spermatozoa was investigated by using the antagonists trifluoperazine and calmidazolium. At high doses both antagonists inhibited the motility of human spermatozoa and induced a concomitant rise in [Ca2+]i and a decline in cAMP. Lower doses of these antagonists, particularly calmidazolium, suppressed the ability of human spermatozoa to generate reactive oxygen species and exhibit sperm-oocyte fusion, without influencing [Ca2+]i, cAMP, or motility. This inhibition of sperm-oocyte fusion was effective even if the spermatozoa were subsequently exposed to A23187, suggesting that calmodulin may regulate this aspect of human sperm function at a point downstream from calcium influx. Both radiolabelling and affinity chromatography techniques were used to detect a number of calcium-dependent and calcium-independent calmodulin acceptor proteins in the human spermatozoon. The major calcium-dependent acceptor proteins exhibited Mr values of 32,000 and 22,000-27,000, respectively, and did not appear to be associated with the sperm plasma membrane.
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Affiliation(s)
- R J Aitken
- MRC Unit of Reproductive Biology, Edinburgh, Scotland
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21
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Chapter 3 Myoblast Fusion–A Mechanistic Analysis. ACTA ACUST UNITED AC 1988. [DOI: 10.1016/s0070-2161(08)60131-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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22
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RAPUANO MARY, PRIVES JOAV. 12-0-Tetradecanoylphorbol-13-Acetate Blocks Myogenic Cell Fusion by Interfering with the Ca2+Signal Transduction Pathway. Ann N Y Acad Sci 1987. [DOI: 10.1111/j.1749-6632.1987.tb29509.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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23
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Watanabe N, Kobayashi M, Iwasaki M, Ishibashi O, Takata Y, Shigeta Y. Insulin binding to differentiating muscle cell line L6. Diabetes Res Clin Pract 1986; 2:283-9. [PMID: 3536369 DOI: 10.1016/s0168-8227(86)80005-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
We studied insulin binding to cultured differentiating muscle cell line L6. Insulin binding to the cells reached a plateau after incubation with 125I-insulin for 4 h at 22 degrees C, and was at an optimum at pH 7.8. Preincubation with 10 microM of hydrocortisone for 36 h at 37 degrees C resulted in significantly increased insulin binding (1.73 +/- 0.12 ng/mg protein for treated cells vs. 1.13 +/- 0.025 ng/mg protein for control cells, mean +/- SD, P less than 0.001). Preincubation with 1 microM of hydrocortisone or 1 microM of dexamethasone also led to increased binding. The number of insulin-binding sites per cell increased 2.5-fold in glucocorticoid-treated cells (9.7 X 10(3) sites/cell for treated vs. 3.8 X 10(3) sites/cell for control cells). Preincubation with trifluoperazine (5 microM), a calmodulin inhibitor, did not affect insulin binding to the cells. These results indicate that glucocorticoid might have some important role in regulating the number of insulin receptors in L6 muscle cells.
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24
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Abe S, Takeda J. Possible involvement of calmodulin and the cytoskeleton in electrofusion of plant protoplasts. PLANT PHYSIOLOGY 1986; 81:1151-5. [PMID: 16664960 PMCID: PMC1075502 DOI: 10.1104/pp.81.4.1151] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
Calmodulin antagonists, trifluoperazine, chlorpromazine, calmidazolium, N-(6-aminohexyl)-5-chloro-1-naphthalenesulfonamide (W-7), strongly inhibited the electrofusion of barley (Hordeum vulgare L. cv Moor) protoplasts with a marked increase of broken fusion products, after 60 minutes of incubation. W-5, a dechlorinated analog of W-7, was found less effective for the inhibition than W-7. Ethyleneglycol-bis(beta- aminoethylether)-N,N'-tetraacetic acid a Ca(2+) chelator, La(3+), a surface Ca(2+) antagonist, and verapamil, a Ca(2+) channel blocker, also inhibited electrofusion. Dielectrophoresis was inhibited by La(3+). A microtubule inhibitor, vinblastine, inhibited electrofusion strongly while colchicine, slightly. A microfilament inhibitor, cytochalasin B, promoted fused cells to become spherical while phalloidin did not affect electrofusion.
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Affiliation(s)
- S Abe
- Institute of Agricultural Environment Control, College of Agriculture, Ehime University, 3-5-7 Tarumi, Matsuyama 790, Japan
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25
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Ohno-Shosaku T, Okada Y. Electric pulse-induced fusion of mouse lymphoma cells: roles of divalent cations and membrane lipid domains. J Membr Biol 1985; 85:269-80. [PMID: 3897548 DOI: 10.1007/bf01871522] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Mouse leukemic lymphoblasts (L5178Y) brought into close contact by dielectrophoresis underwent cell fusion following the application of electrical pulses in the presence of electrolytes. The electrically fused cells became spherical after switching off the dielectrophoretic field. Fusion between a cell vitally stained with Janus Green and that with Neutral Red resulted in the homokaryon with a mixed color. Intracellular potentials simultaneously recorded from the two cells located on both sides of the homokaryon were identical. The fusion efficiency was remarkably dependent upon temperature, displaying a discontinuity at about 11 degrees C in the Arrhenius plot. The extracellular application of phospholipase-A2 or -C suppressed the fusion yield. Thus, it appears that the phospholipid domains play a crucial role in the electric pulse-induced cell fusion. Treatment of the cells with proteolytic enzymes markedly enhanced the fusion yield, presumably due to removing the glycocalix and/or giving rise to fusion-potent, protein-free lipid domains. The presence of millimolar concentrations of divalent cations (irrespective of Mg2+ or Ca2+) as well as of micromolar concentrations of Ca2+ (but not Mg2+) was prerequisite to the resealing of membranes suffered from electrical breakdown upon exposure to electric pulses. In addition, extracellular Ca2+ (but not Mg2+) ions at more than micromolar concentrations were indispensable for the cell fusion.
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26
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Knudsen KA. The calcium-dependent myoblast adhesion that precedes cell fusion is mediated by glycoproteins. J Biophys Biochem Cytol 1985; 101:891-7. [PMID: 4030897 PMCID: PMC2113721 DOI: 10.1083/jcb.101.3.891] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Presumptive myoblasts from explants of chick embryo pectoral muscle proliferate, differentiate, and fuse to form multinucleate myotubes. One event critical to multinucleate cell formation is the specific adhesion of myoblasts before union of their membranes. In the studies reported here five known inhibitors of myotube formation--trifluoperazine, sodium butyrate, chloroquine, 1,10 phenanthroline, and tunicamycin--were tested for their effect on the Ca++-dependent myoblast adhesion step. The first four inhibitors of myotube formation do not perturb myoblast adhesion but rather block fusion of aggregated cells, which suggests that these agents perturb molecular events required for the union of the lipid bilayers. By contrast, tunicamycin exerts its effect by inhibiting the myoblast adhesion step, thereby blocking myotube formation. The effect of tunicamycin can be blocked by a protease inhibitor, however, which implies that the carbohydrate residues protect the glycoproteins from proteolytic degradation rather than participate directly in cell-cell adhesion. Whereas trypsin treatment of myoblasts in the absence of Ca++ destroys the cells' ability to exhibit Ca++-dependent adhesion, the presence of Ca++ during trypsin treatment inhibits the enzyme's effect, which suggests that myoblast adhesion is mediated by a glycoprotein(s) that has a conformation affected by Ca++. Finally, myoblast adhesion is inhibited by an antiserum raised against fusion-competent myoblasts. The effect of the antiserum is blocked by a fraction from the detergent extract of pectoral muscle that binds to immobilized wheat germ agglutinin, which again suggests that glycoproteins mediate Ca++-dependent myoblast adhesion.
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27
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Grimes HD, Boss WF. Intracellular calcium and calmodulin involvement in protoplast fusion. PLANT PHYSIOLOGY 1985; 79:253-8. [PMID: 16664381 PMCID: PMC1074861 DOI: 10.1104/pp.79.1.253] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
(45)Ca(2+) uptake was compared between fusogenic and nonfusogenic Daucus carota L. protoplasts. Fusogenic protoplasts took 10 minutes to reach calcium equilibrium compared to 5 minutes in the nonfusogenic protoplasts. Intracellular stores of calcium were manipulated by isolating protoplasts in different calcium regimes. Lowering of intracellular calcium lowered fusion potential, while raising intracellular stores of calcium enhanced fusion potential. Regardless of the amount of calcium sequestered in a store, mobilization with A23187 increased fusion levels within 10 minutes. Calmodulin antagonists were potent inhibitors of protoplast fusion. This inhibition was obtained by treating cells with the calmodulin antagonists during protoplast isolation. A23187, however, only allowed a partial recovery from this inhibition, indicating that calcium flux alone was not sufficient for maximum fusion potential. On the basis of the evidence presented, we propose that calcium fluxes during protoplast isolation activate a calmodulin-mediated biochemical process that is necessary for the formation or maintenance of a fusion permissive state.
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Affiliation(s)
- H D Grimes
- Department of Botany, North Carolina State University, Raleigh, North Carolina 27695-7612
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28
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29
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Micklem KJ, Nyaruwe A, Alder GM, Pasternak CA. The effect of Ca2+ on virus-cell fusion and permeability changes. Cell Calcium 1984; 5:537-50. [PMID: 6098375 DOI: 10.1016/0143-4160(84)90030-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Sendai virus-mediated permeability changes in Lettre cells or red blood cells are affected by extracellular Ca2+ in the following way: the lag period to onset of permeability changes is lengthened and the subsequent extent of leakage is reduced. Ca2+ neither stimulates nor inhibits fusion of the viral envelope to the plasma membrane of Lettre cells or red blood cells. It is concluded that Ca2+ protects cells against virally-induced permeability changes in a manner not involving membrane fusion.
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30
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Micklem KJ, Alder GM, Pasternak CA. Effect of Ca2+-antagonists on virally-induced cell-permeability changes. Cell Biochem Funct 1984; 2:249-53. [PMID: 6097372 DOI: 10.1002/cbf.290020412] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Sendai virus-mediated permeability changes in cells are affected by extracellular Ca2+ or Mn2+ as follows: the lag period to onset of permeability changes is lengthened and the subsequent extent of leakage is reduced. Drugs that block Ca2+ action in excitable cells, such as verapamil and prenylamine, and drugs that inhibit the action of calmodulin, such as trifluoperazine and R24571, have an effect opposite to that of Ca2+: lag is shortened and extent of leakage is increased. The concentration at which either type of drug shows 50% of maximal effect is similar to the concentration at which 50% of binding by drug to calmodulin is achieved. It is concluded that calmodulin may be involved in protecting cells against virally-mediated membrane damage; alternatively the action of calmodulin-binding drugs may not be as specific as currently thought.
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