Résumé :
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Saba Abdul-Hussein, Homa Tajsharghi Department of Pathology, Institute of Biomedicine, University of Gothenburg, 413 45 Gothenburg, Sweden In vertebrates skeletal muscle is found throughout the body and forms during the entire life span. Adult skeletal muscle displays high regenerative capacity with satellite cells as the primary source of this remarkable ability. Satellite cells are quiescent muscle progenitors located between myofibers and their surrounding basal lamina. The formation of muscular tissue (myogenesis) is a complex process, taking place during embryonic development, postnatal growth and adult muscle regeneration. Myogennesis is a procedure marked by specific changes in muscle cell morphology and cytoarchitecture through the fusion of myoblasts into multinucleated myotubes and assembly of contractile sarcomeric myofibrils. The formation of contractile myofibrils involves the transition of myoblast cytoarchitecture, which requires change in expression of proteins from non-muscle-specific to muscle-specific isoforms.In this study, combined molecular and immunocytochemistry methods were used to investigate the sarcomeric gene and protein expression profile during myoblast proliferation and differentiation in both human and mouse muscle cell lines. We observed expression of all the investigated panel of sarcomeric gene transcripts and also early expression of a number of the investigated sarcomeric proteins at the proliferated myoblasts. In addition, a majority of day-6-differentiated cells expressed all the investigated sarcomeric proteins. The results presented herein provide novel insights into the onset of the expression pattern of the sarcomeric gene and protein. In addition, our study demonstrates the effectiveness of differentiation system in vitro, which transforms undifferentiated and star-shaped myoblasts, into long multinucleated myotubes, showing the features of contractile muscle cell, which might lead to the clinical usage of skeletal muscle tissue engineering.
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