The gene silencing mediated by RNA interference on macrophage migration inhibitory factor expression in human alveolar epithelial cell line A549

Abstract

Objective To study the inhibitory effect on macrophage migratory inhibitory factor (MIF) expression by MIF small interference RNA (siRNA)in human alveolar epithelial cell line A549. Methods After MIF siRNA was transfected into human alveolar epithial cells A549 with Interferin, RT-PCR was carried out to assess the dose-response of MIF siRNA's effect on MIF expression. Cell immumofluorescence method was used to analyze the expression of MIF protein. MTT cell proliferation assay was performed to detect the cytotoxicity of MIF siRNA to A549 cells, and the survival rate of A549 cells caused by lipopolysaccharide(LPS). Results (1) Only when the concentration was over 50 nmol/L, MIF siRNA significantly downregulated the MIF mRNA expression. (2) MIF siRNA also greatly reduced the expression of MIF fluorescent protein, which could be reversed by MIF. (3)MIF siRNA transfection had almost no toxicity to A549 cells, but also could reduce the cell mortality and increase the survival rate caused by LPS. Conclusions MIF siRNA can specially silence the expression of target gene MIF mRNA and reduce the MIF protein in A549 cells, therefore MIF siRNA may exert its safeguard to the death of cell induced by LPS. Key words: Macrophage migration inhibitory factor; Small interference RNA; Human alevolar epithelial cell A549; Lipopolysaccharide