Résumé :
|
Purpose: The comprehension of the human skeletal muscle development, homeostasis and physiopathology, and the set up of new therapeutic tools, mandate the cellular investigation of skeletal muscle compartments. In situ, we assessed the phenotype and localization of muscle cells on biopsy sections. In vitro, we analysed the main cell populations from the onset of cell culture, their potential relationships and phenotypical evolutions, and their differentiation abilities. Methods: Immunohistochemistry was performed on human muscle cryostat sections. Primary cell cultures were established upon enzymatic dissociation. Immunophenotypic analyses were performed by flow cytometry and completed by immunocytochemistry. The two main cell populations were separated using immunomagnetic beads, and expanded. Differentiation studies were performed in vitro using specific media. Results: Classical mesenchymal (MSC) markers and additional ones (CD 10, 13, 15, 29, 34, 44, 47, 49, 56, 62, 73, 90, 105, 106, 146) were expressed by resident muscle cells, which were classified according to their position relatively to muscle fibers, basement membranes, and intramuscular vessels. CD56+ satellite cells co-expressed rarely the CD90, CD146 or CD34 markers but no other MSC marker. In culture, two main populations were identified, separated, and distinguished by expression of CD56+ or CD15+ antigens, while a third population of CD34+ cells disappeared rapidly. When expanded, CD56+ and CD15+ cells expressed all MSC markers, similar to that harbored by human BM-MSC, while keeping heterogeneity. The CD56+ cells expressed myogenic and chondrogenic abilities and osteogenic markers, while CD15+ presented adipogenic and chondrogenic capacities, and osteogenic markers. Conclusions: These data underline the diversity of cells participating to human muscle structures. They suggest that different populations express phenotypical markers typical of myogenic and/or MSC, and present mutually exclusive lineage restrictions. Supported by grants from Genostem and the AFM.
|