Research topic: The project aims at studying cell communication during human skeletal muscle regeneration in aging and pathological conditions. Muscle releases ‘myokines’, especially during the early stages of differentiation, which corresponds to the early stage of muscle regeneration. Tissue repair involves many cell types: inflammatory, interstitial, or even fibrotic in pathological situation. The complex orchestration of muscle regeneration necessitates a well-defined set of secreted molecules allowing cell-cell communication and therefore co-regulation. Muscle regeneration is less efficient in the elderly after falls or surgery, while we have previously shown that muscle stem cells have a good potential for proliferation and differentiation. In addition, it has been shown that the muscle secretome can be disturbed in several pathological situations. This project investigates the secretome of adult muscle cells across control, aged and pathological subjects and the impact of these secreted molecules on muscle regeneration. Secretome of muscle cells have already been performed and the post-doctoral research fellow will perform functional follow-up experiments to assess the impact of selected myokines on muscle regeneration. Using innovative approaches with co-culture systems and a xenograft model, the project will deliver novel mechanistic insights into how the kinetics of muscle regeneration is deregulated by secreted molecules during aging and in pathologies, and how these can be proposed as therapeutic targets to promote muscle health.