The effect of down-regulation of CCL5 on lipopolysaccharide-induced WI-38 fibroblast injury: a potential role for infantile pneumonia

OBJECTIVE(S): Aberrant expression of CCL5 has been found in several kinds of inflammatory diseases, and the roles of CCL5 in these diseases have also been reported. However, the role of CCL5 in infantile pneumonia is still unclear. Thus, the function and acting mechanism of CCL5 in the in vitro model of infantile pneumonia were researched in this study. MATERIALS AND METHODS: Human fetal lung fibroblast WI-38 cells were subjected with lipopolysaccharide (LPS) to mimic an in vitro model of pneumonia. CCL5 was silenced by transfection with CCL5-targeted siRNA, and then cell viability, apoptosis, and the expressions of apoptosis-associated factors were respectively assessed by CCK-8 assay, flow cytometry and Western blot. Besides, expressions of CCL5 and pro-inflammatory factors were analyzed by qRT-PCR and Western blot. The secretions of pro-inflammatory factors were measured by ELISA. Finally, the expressions of main factors in JNK and NF-κB pathways were detected. RESULTS: LPS treatment suppressed cell viability, promoted cell apoptosis, and enhanced the secretion of IL-6, MCP-1, and TNF-α. Overexpression of CCL5 was found in LPS-treated cells. CCL5 silence protected WI-38 cells from LPS-induced inflammatory damage, with increasing cell viability, inhibiting cell apoptosis, and reducing the production of pro-inflammatory cytokines. Besides, CCL5 silence inhibited LPS-induced activations of JNK and NF-κB pathways. CONCLUSION: Down-regulation of CCL5 could protect WI-38 cells from LPS-induced inflammatory damage via inactivating JNK and NF-κB pathways.