To further evaluate the role of GPR‐81 in lactate‐mediated myofibroblast differentiation under hypoxic conditions, we next treated control and IPF fibroblasts with lactate in the presence or absence of the GPR‐81 antagonist, 3‐hydroxybutyric acid (Chen, Zhou, et al., 2021; Shen et al., 2015). The gene discussed is HCAR1; the disease is idiopathic pulmonary fibrosis.