SMAD3 and idiopathic pulmonary fibrosis: TGF-β1, a profibrotic cytokine with a major role in IPF pathogenesis25,33 and SMAD3, integral to the TGF-β signaling pathway57, were predicted as upstream regulators in human AbBa and mouse ADI fibrotic niches, pointing to a shared TGF-β-driven fibrotic signaling pathway.