TGF-beta in the UCB-MSCs inhibit TNF-alpha in human mast cells and atopic dermatitis

Abstract

Abstract It is well known that umbilical cord blood-derived mesenchymal stem cells (UCB-MSCs) have been effective therapy in autoimmune inflammatory disease such as atopic dermatitis (AD), rheumatoid arthritis (RA) and psoriasis. Especially, UCB-MSC has a prominent therapeutic effect on AD. However, there is not much research on the mechanism of alleviation of AD by UCB-MSCs. In this study, we investigated the mechanism of AD therapy by UCB-MSCs, using human mast cells as the major pathogenic cells in AD. LAD2 cells were stimulated with IL- 33(30ng/ml) and Ionomycin (1uM) under IgE-XL condition and they secreted a significant amount of TNF-a. TNFa was significantly inhibited by co-culture with UCB-MSCs. UCB-MSCs secreted TGF-beta and PGE2, which play a crucial role in immune regulation. TNF-a of LAD2 was increased when co-cultured with UCB-MSCs after TGF-b siRNA transfection. Nevertheless, inhibition of PGE2 using indomethacin, NS398 and celecoxib did not restore secretion of TNF-a. At the protein level, we examined the ERK, JNK and AKT signaling pathways involved in TNF-α, and only the ERK signaling pathway was associated with TNF-α inhibition. Finally, we found that TNFa is regulated by TGFb induced by UCB-MSC in a DF-induced mouse model. Taken together, our findings suggest that TGF-b may play an important role in regulating mast cells in AD rather than PGE2 in UCB-MSCs.