TGFB1 and idiopathic pulmonary fibrosis: While PGF2α has also been shown in vitro to prompt fibroblast proliferation and collagen production in a TGF-β1–independent fashion, neither the effect size, specific PGF2α-dependent fibroblast subpopulations, nor the integration of this signaling axis into other preclinical PF models or human IPF have been defined.