Osr1 controls the pro-regenerative response of Fibro-Adipogenic Progenitors

Purpose: To study the requirement of Osr1 expression for FAP function during skeletal muscle regeneration. Methods: We sequenced total mRNAs isolated from adult FAPs FACS sorted from 3 and 7 day post injured hindlimb skeletal muscle of Ctrl (Osr1flox/+ CAGG Cre+) and Osr1 cKO (Osr1flox/flox CAGG Cre+) mice. Results: Loss of Osr1 leads to pro-fibrotic orientation of FAPs and impairs both FAP-macrophage and FAP-MuSCs communication network resulting in impaired regenerative myogenesis and persistent fibrosis. Conclusions: Osr1 is a key transcriptional regulator of FAP regenerative function protecting FAPs from assuming a detrimental pro-fibrotic and anti-myogenic state. Sequencing was performed on RNAs isolated from adult FAPs FACS sorted from 3 and 7 days post injured hindlimb skeletal muscle of Ctrl (Osr1flox/+ CAGG Cre+) and Osr1 cKO (Osr1flox/flox CAGG Cre+) mice.