The present study, performed in primary human lung fibroblasts (isolated from healthy and IPF lung tissues), lung-fibroblasts cell lines and a mouse model of lung fibrosis, identified new regulatory pathways concerning fibroblasts activation and proliferation, involving circTADA2A, miR-526b, miR-203, Cav1, and Cav2. This evidence concerns the gene CAV1 and idiopathic pulmonary fibrosis.