By using genetic knockout mice of the two kinases in various models of renal fibrosis, it was shown that loss of Sphk2 is protective and reduces disease parameters, such as in the unilateral ureteral obstruction (UUO) [12,13,14] and diabetic nephropathy models [15], while inhibition of Sphk1 is still not conclusive because in one study it aggravated fibrosis [16], but in another study reduced fibrosis [17]. Here, SPHK2 is linked to renal fibrosis.