BACKGROUND: Lipopolysaccharide (LPS) in bacterial infection of skin wounds delays wound healing. This study aimed to investigate the effects of LPS and endoplasmic reticulum stress in cultured skin fibroblasts and microRNA-211-3p (miR-211-3p) signaling.

MATERIAL AND METHODS: Human skin fibroblasts were cultured in increasing concentrations of LPS at 0 ng/ml, 5 ng/ml, 10 ng/ml, and 20 ng/ml for 0, 12 h, 24 h, 36 h, and 48 h. Cell proliferation was determined using the MTT assay. Protein expression levels of the transcription factors GRP78, CHOP, p-JNK, and the endoplasmic reticulum stress apoptosis proteins, caspase-12 and Bcl-2, were determined by Western blot. The expression of miR-211-3p in human skin fibroblasts was detected by quantitative polymerase chain reaction (qPCR).

RESULTS: Cell proliferation of human skin fibroblasts decreased with increasing concentrations of LPS in a dose-dependent and time-dependent way. Protein levels of GRP78, CHOP, p-JNK, caspase-12, and Bcl-2 were increased 8 h and 12 h after LPS treatment compared with 0 h and 4 h after treatment. However, the expression of miR-211-3p was decreased in human skin fibroblasts after treatment with LPS. When miR-211-3p was overexpressed, the endoplasmic reticulum stress/CHOP related proteins, including GRP78, CHOP, p-JNK, caspase-12, and Bcl-2 were unchanged after the addition of LPS. Overexpression of miR-211-3p also reduced inhibitory effects of LPS on the growth of human skin fibroblasts.

CONCLUSIONS: This study showed that microRNA-211-3p had a role in the effects of LPS on endoplasmic reticulum stress and CHOP activation in cultured human skin fibroblasts.

Keywords: Endoplasmic reticulum stress, Lipopolysaccharides, Endoplasmic Reticulum Chaperone BiP, Skin