SPHK1 and pulmonary fibrosis: Our results here showed that the deletion of Sphk1 in AECs and fibroblasts conferred the protection against BLM-induced lung fibrosis in mice (Figure 1 and Figure 2), while the deletion of Sphk1 in endothelial cells did not protect the mice from BLM-induced lung fibrosis, suggesting a differential role for SPHK1-derived S1P from lung epithelial cells and fibroblasts in fibrogenesis compared to the endothelium.