SGCB and pulmonary fibrosis: The results from this study link CYB5R3 deficiency to the upregulation of pro-fibrotic TGF-β1 signaling, suggesting that strategies aiming at CYB5R3 expression and activity, such as the use of sGC agonists, may lessen the severity of pulmonary fibrosis, specifically in the context of the aging lung.