Mesenchymal stem cells and a vitamin D receptor agonist additively suppress T helper 17 cells and the related inflammatory response in the kidney

Mesenchymal stem cells (MSCs) suppress T helper (Th)17 cell differentiation and are being clinically pursued for conditions associated with aberrant Th17 responses. Whether such immunomodulatory effects are enhanced by coadministration of MSCs with other agents is not well known. In the present study, individual and combined effects of MSCs and the vitamin D receptor (VDR) agonist paricalcitol on Th17 induction were investigated in vitro and in a mouse model of sterile kidney inflammation (unilateral ureteral obstruction). In vitro, MSCs and paricalcitol additively suppressed Th17 differentiation, although only MSCs suppressed expression of Th17-associated transcriptions factors. Combined administration of MSCs and paricalcitol resulted in an early (day 3) reduction of intrarenal CD4+ and CD8+ T cells, CD11b+/lymphocyte antigen 6G+ neutrophils, and inflammatory (lymphocyte antigen 6Chi) monocytes as well as reduced transcript for IL-17 compared with untreated animals. Later (day 8), obstructed kidneys of ...