IL-1β enhances human placenta-derived mesenchymal stromal cells ability to mediate Th1/Th2 and Th1/CD4±IL-10± T cell balance and regulates its adhesion, proliferation and migration via PD-L1

Human placenta-derived mesenchymal stromal cells (hPMSCs) are promising candidates for the treatment of graft-versus-host disease (GVHD), which is associated with high IL-1beta levels. In this study, the effects of IL-1beta and hPMSCs on each other were investigated by analyzing the proportion of Th1, Th2 and CD4(+)IL-10(+) T cells and PD-L1 expression, as well as the adhesion, migration, and proliferation of hPMSCs. The results showed that hPMSCs decreased IL-1beta levels and downregulated Th1/Th2 and Th1/CD4(+)IL-10(+) T cells ratios in the GVHD model. The in vitro results revealed that IL-1beta strengthened the hPMSCs capacity to reduce the Th1/Th2 and Th1/CD4(+)IL-10(+) T cell ratios, inhibited the adhesion and proliferation of hPMSCs and increased PD-L1 expression on hPMSCs via the JAK and NF-kappaB pathways. Overall, these findings suggested that hPMSCs alleviate GVHD by decreasing IL-1beta level and maintaining the balance among different T cell subsets. IL-1beta enhanced the ability of hPMSCs to balance different T cell subsets and inhibited hPMSCs adhesion and proliferation by regulating PD-L1 expression via the JAK and NF-kappaB pathways.