OBJECTIVETo establish the stably lower expression of vascular cell adhesion molecule-1 (VCAM-1) in MSC cell line (C3H10T1/2) by siRNA technology, and explore the effect of knockdown of VCAM-1 on the immunologic regulation capacity of murine MSC.

METHODSThe mouse GV118-VCAM-1-RNAi retrovirus vector was constructed by gene recombination technology. The recombinant plasmid was identified by restriction analysis and sequencing, and then the recombinant plasmid GV118-VCAM-1-RNAi was transfected into 293 cells by Lipofectamine, and the supernatant was collected to transfect C3H10T1/2. Moreover, the VCAM-1 lower expression on MSC was evaluated by flow cytometry and fluorescent microscopy. The knockdown VCAM-1 MSC was sorted by flow cytometry. Furthermore, the inhibitory effect of the knockdown VCAM-1 MSC on lymphocyte proliferation was tested by lymphoblast transformation assay (LTT) and mixed lymphocyte reaction assay(MLR).

RESULTSThe recombinant retroviral vector of knockdown VCAM-1 (GV118-VCAM-1-RNAi) was successfully constructed and transfected into mouse MSC cell line C3H10T1/2. The knockdown VCAM-1/MSC was obtained by flow cytometric sorting. The LTT and MLR assay showed that the immunosuppressive effect of MSC lower-expressing VCAM-1 dramatically decreased (P<0.05).

CONCLUSIONKnockdown VCAM-1 in MSC can significantly down-regulate the inhibitory capability of MSC on the proliferation of T-cells. The data of this study laid an experimental foundation for studying effect of VCAM-1 transfecting into MSC on immune function.