Functional properties of muscle-derived cells related to morphological characteristics

Satellite cells represent a specific lineage of myogenic progenitors that allow skeletal muscle postnatal growth and repair. They have been described as being heterogeneous in nature, a characteristic associated with functional disparities. Here, we aimed at determining whether the morphometric characteristics of freshly extracted turkey muscle-derived cells (MDC) could represent a distinctive criterion between them and could also be associated with their behavioural features. Morphometric analysis showed that MDC displayed wide cell size diversity, from 4 to 10 mum. Lineage marker analysis was performed on MDC sorted by their size using counterflow centrifugal elutriation and showed that the cell size was associated with the specific expression of myogenic markers, revealing different commitment levels. In vitro, the smallest MDC exhibited limited myogenic activity while larger MDC displayed a myogenic potential that increased with their size. Ultrastructural analysis revealed that the smallest MDC shared quiescent cell features, whereas the other cells displayed metabolic activity that also increased as a function of their size. Collectively, our results demonstrate that the size of freshly extracted MDC is indicative of their respective progression towards myogenic differentiation lineage. This criterion could be useful for the early separation of more or less committed cells in the myogenic programme.