Abstract:

Objective： The therapeutic potential of umbilical cord mesenchymal stem cells (UC-MSCs) in rheumatoid arthritis (RA) has attracted more and more attention, because of it can suppress the various inflammatory effects of T cells. Galectin-1 is highly expressed in UC-MSCs, as the first lectin mediating the immunomodulatory effect of MSCs. Our study will investigate the effects of galectin-1 in regulation of UC-MSCs on rheumatoid arthritis T cells. Methods: Lentivirus transfected shRNA technique was used to knock down the expression of galectin-1 in UC-MSCs to construct UC-MSCs(Gal-1-). The effects of UC-MSCs and UC-MSCs(Gal-1-) on CD4+ T cells in RA patients were investigated by contact system, including negative control group (CD4+ T cells), positive control group ［CD4+ T-phytohemagg lutinin (PHA)］, UC-MSCs-CD4+ T cells co-culture group, UC-MSCs(control shRNA)-CD4+ T cells co-culture group, and UC-MSCs(Gal-1-)-CD4+ T cells co-culture group. The proliferation of CD4+ T cells was detected by MTS assay. The level of tumor necrosis factors α (TNF-α) in cells supernatant was detected by enzyme linked immunosorbent assay (ELISA). The effect of UC-MSCs on helper T cell (Th) subset was detected by flow cytometry. Results: In vitro, UC-MSCs were capable of inhibiting PHA induced proliferation of CD4+ T cells from RA patients, but UC-MSCs(Gal-1-) did not show the significant inhibitory effect. Galectin-1 affect the TNF-α level of CD4+ T cells regulated by UC-MSCs. UC-MSCs and UC-MSCs(control shRNA) significantly inhibited the expression of TNF-α in PHA-induced CD4+ T cells. However, UC-MSCs(Gal-1-) had no significant inhibitory effect. Furthermore, the Th1 cells were also significantly suppressed by UC-MSCs and UC-MSCs(control shRNA) (4.83%±1.37% and 5.13%±0.87%，P=0.012 and P=0.018). These was no significant difference in the proportion of the Th1 cells between the control group and UC-MSCs(Gal-1-) group (8.51%±2.04% and 6.41%±0.96%，P=0.101). The Th2 cells were protected after silence galectin-1 in UC-MSCs, whereas there was no significant difference. The proportion of Th17 was decreased by co-culture with UC-MSCs and UC-MSCs(control shRNA), but these was also no significant difference. Conclusion: UC-MSCs can inhibit the proliferation and differentiation of CD4+ T cells from RA patients, but these effect declined after knocking down the expression of galectin-1. Galectin-1 maybe take part in the regulation of UC-MSCs on rheumatoid arthritis CD4+ T cells.

Key words: Arthritis, rheumatoid, Mesenchymal stem cells, Galectins