CCN4 and idiopathic pulmonary fibrosis: Furthermore, DAPK1 is an interferon-induced serine/threonine kinase involved in programmed cell death and was significantly decreased by TGFβ1 + WISP1 treatment, making fibroblasts resistant to apoptosis, which further contributes to disease pathophysiology and fibrogenesis in both non-diseased and IPF primary lung fibroblasts.