CEBPZ and pulmonary fibrosis: In addition, ER stress-induced C/EBPζ upregulation can increase Sonic Hedgehog expression and promote its secretion from type II alveolar epithelial cells, which then activates lung fibroblasts through activating the Hedgehog signaling pathway and polarizes macrophages into the M2 stage in an osteopontin-dependent manner, resulting in pulmonary fibrosis [246, 247].