HIF1A and idiopathic pulmonary fibrosis: As such, we utilized an in vitro model of IPF wherein cells were cultured in the presence of CoCl2 under hypoxic conditions rather than TGF-β1 (Huang et al., 2020), as this has been shown to induce fibroblast proliferation and nuclear HIF-1α accumulation (Song et al., 2018).