immunomodulatory effects of human umbilical cord wharton's jelly-derived mesenchymal stem cells on differentiation, maturation and endocytosis of monocyte-derived dendritic cells.

the wharton’s jelly of the umbilical cord is believed to be a source of mesenchymal stem cells (mscs) which can be therapeutically applied in degenerative diseases. in this study, we investigated the immunomodulatory effect of umbilical cord derived- mesenchymal stem  cells (uc-mscs) and  bone  marrow-derived-mesenchymal stem  cells (bm-mscs) on differentiation, maturation, and endocytosis of monocyte-derived dendritic cells in a transwell culture system under laboratory conditions. monocytes were differentiated into immature dendritic cells (idcs) in the presence of gm-csf and il-4 for 6 days and then differentiated into mature dendritic cells (mdcs) in the presence of tnf-α for 2 days. in every stage of differentiation, immature and mature dendritic cells were separately co- cultured with uc-mscs and bm-mscs. the findings showed that uc-mscs and bm-mscs inhibited strongly differentiation and maturation of dendritic cells at higher dilution ratios (1:1). the bm-mscs and uc-mscs showed more inhibitory effect on cd1a, cd83, cd86 expression, and dendritic cell endocytic activity, respectively. on the other hand, these cells severely up-regulated cd14 marker expression.  we concluded that uc-mscs and bm-mscs could inhibit differentiation, maturation and endocytosis in monocyte-derived dcs through the secreted factors and free of any cell- cell contacts  under  laboratory conditions. as dcs  are believed to  be the  main antigen presenting cells for naïve t cells in triggering immune responses, it would be logical that their inhibitory effect on differentiation, maturation and function can decrease or modulate immune and inflammatory responses.