SPHK1 and idiopathic pulmonary fibrosis: Accumulating evidence has firmly established a prominent role for SPHK1/ S1P signaling in the pathobiology of IPF and murine lung fibrosis but the detailed molecular mechanisms involved are not fully understood, nor whether blocking SPHK1 activation following exposure to fibrogenic agents is protective [3,4,15,20,21,39,40].