Mesenchymal stem cells inhibit the activation and proliferation of CD4+ T cells in Sjögren syndrome by promoting prostaglandin E2, hepatocyte growth factor and indoleamine 2, 3-dioxygenase secretion

Abstract

Objective To investigate the suppressive effect of prostaglandin E2 (PGE2), hepatocyte growth factor (HGF) and indoleamine 2, 3-dioxygenase (IDO) whose secretion was promoted by human um-bilical cord mesenchymal stem cells(MSCs) on the activated peripheral blood CD4+ T cells in primary Sjogren syndrome (pSS) in vitro. Methods Primary cultured umbilical cord MSCs were identified by flow cytometry, and peripheral blood CD4+ T cells were sorted in pSS patients. CD4+ T cells were cultured with CD3, CD28 antibody for 72 h to be the activated(control group); the activated CD4+ T cells were co-cultured with MSCs for 72 h(MSCs group) or MSCs were pre-stimulated with interferon-γ (IFN-γ), then the activated CD4+ T cells were co-cultured with pre-stimulated MSCs for 72 h (pre-stimulated group). The suspension of CD4+ T cells were collected and counted. PGE2, HGF and IDO in the supernatants were detected by ELISA. Mean in groups were compared using ANOVA, and multiple comparisons were used with LSD method. Results The concentrations of PGE2 in the supernatant of the control group, MSCs group and pre-stimulated group were (111±4) pg/ml,(2 814±6) pg/ml and (2 716±8) pg/ml (F=167 292.12, P<0.01) respectively. The concentrations of HGF in the above groups were (597±9) pg/ml, (383±9) pg/ml and (727±12) pg/ml(F=878.61, P<0.01) respectively. The concentrations of IDO in the above groups were (143±4) pg/ml, (835±5) pg/ml and (588±3) pg/ml (F=21 104.41, P<0.01) respectively. Compared with the control group, levels of PGE2 significantly increased in the MSCs group and the pre-stimulated group that CD4+ T cells were co-cultured with MSCs (t=509.88, P<0.01 and t=491.48, P<0.01), and levels of IDO also significantly increased (t=202.69, P<0.01 and t=130.39, P<0.01), while the activation and proliferation of CD4+ T cells were inhibited (t=-16.20, P<0.01 and t=-31.48, P<0.01). Compared with MSCs group, levels of PGE2 and IDO significantly decreased in pre-stimulated group(t=-18.40, P<0.01 and t=-72.30, P<0.01), and levels of HGF significantly increased in pre-stimulated group(t=41.51, P<0.01), while the activation and proliferation of CD4+ T cells were further inhibited(t=-15.28, P<0.01). Conclusion MSCs can inhibit the activation and proliferation of CD4+ T cells in pSS in vitro. The suppressive effect of MSCs may be achieved by promoting secretion of cytokines such as PGE2, HGF and IDO. HGF plays a more important role in the suppressive effect of MSCs pre-stimulated with IFN-γ. Too much PGE2 or IDO propably results in negative feedback regulation of MSCs. Key words: Sjogren's syndrome; Mesenchymal stem cells; Umbilical cord; Dinoprostone; Hepato-cyte growth factor; Indoleamine-pyrrole 2, 3-dioxygenase; CD4-positive T-lymphocytes