Lkb1 is an important regulator of Treg differentiation and proliferation of amniotic mesenchymal stem cells.

ABSTRACT

In this study, we aimed to explore the role of liver kinase b1 (Lkb1) in the biological characteristics and immune regulation of amniotic mesenchymal stem cells (AMSCs). AMSCs were identified via the cell surface markers using flow cytometry. We knocked down the expression of Lkb1 in AMSCs using lentivirus-mediated Lkb1-specific shRNA. The efficiency of the knockdown was detected by flow cytometry, RT-qPCR, and western blot. The AMSC-related phenotype was determined by flow cytometric analysis via staining surface markers. Fibroblast colony-forming cells (CFU-F) assay and Ki-67 intracellular staining assay were used to determine the proliferative capacity. The differentiated and immunosuppressive capabilities were determined by conditional induction of differentiation and co-culture experiments. We observed that AMSCs along with Lkb1 knockdown (AMSCs-Lkb1) displayed similar cellular morphology and surface antigen expression patterns as those observed in AMSCs. However, AMSCs-Lkb1 exhibited an enhanced differentiation capacity towards osteogenesis and chondrogenesis while it showed defective proliferation and increased apoptosis. Furthermore, AMSCs-Lkb1 showed an enhanced immunosuppressive capacity by directly inhibiting conventional T cells and indirectly inducing production of regulatory T cells (Treg). Interestingly, Treg produced by AMSCs-Lkb1 displayed stronger proliferative capacity as compared to those produced by AMSCs. Our results indicate that Lkb1 plays a vital role in maintaining self-renewal of AMSCs and regulating immune equivalence, and may hold potential for the clinical management of diseases such as GVHD.