The Aim of the Study is to Decipher the Alterations in Signalling Pathways of Skeletal Muscle Stem Cells (Satellite Cells (SCs)) in Individuals With COPD, as Well as to Examine the Effect of Exercise Training on SCs.

Chronic obstructive pulmonary disease (COPD) is now to be considered as a multimorbid disease, originating from a combination of several risk factors (respiratory events in childhood, exposure to inhaled particles, physical inactivity, etc.), and simultaneously affecting several organs. This multi-organ impairment is likely to arise from common biological processes such as systemic inflammation or repair failure. Studying these processes in an organ that is easily accessible to biopsy, such as skeletal muscle, can help in the overall management of COPD. Skeletal muscle wasting (or sarcopenia: loss of muscle mass and force) is also a major comorbidity in COPD, both frequent and associated to increased mortality. Muscle stem cells (satellite cells) are responsible for repairing skeletal muscle tissue after injury, notably after micro-lesions induced by exercise. However, they have been scarcely studied in COPD. In the present project, the team proposes to study repair abnormalities in skeletal muscle tissue by comparing the signalling pathways activated in satellite cells of patients with COPD, before and after a respiratory rehabilitation programme (20 sessions over 8 to 12 weeks). The team will carry out an exhaustive respiratory and muscular assessment at inclusion and at the end of the 20 sessions, evaluating in particular respiratory function and exercise capacity (Pulmonary Function Tests, cardio-pulmonary exercise testing with VO2max measurement, 6-minute walking test, handgrip test) as well as a quadricipital muscle biopsy with the modified Bergström's technique. Muscle biopsies will be used to culture satellite cells and assess their regenerative capacity in vitro, as well as to analyse dysregulated signalling pathways at the transcriptomic level with single-cell RNAsequencing. The results should help to identify new therapeutic avenues for the comprehensive management of multimorbid COPD.