Altogether, our data showed that, in interstitial fibroblasts, activation of S1P1 and S1P3 can trigger Epo production (Figure 6), and this could have a therapeutic impact for future treatment strategies of anemia in patients with CKD, or where a tissue-protective effect of Epo is desirable to prevent organ injury during acute and chronic inflammatory disease. Here, S1PR3 is linked to chronic kidney disease.