SPHK1 and idiopathic pulmonary fibrosis: Targeting the SPHK1/S1P/S1PR axis, PF543 (SPHK1 inhibitor), Mito TEMPO (mitochondria-targeted superoxide dismutase, which can reduce mtROS) and verteporfin (YAP inhibitor) have been reported, but these drugs have not entered clinical trials on IPF treatment.