Lysine demethylase 1A exacerbates LPS-induced inflammation of vascular smooth muscle cells through modulation of NF-κB activation

Abstract

Purpose: To study the effect of lysine demethylase 1A (LSD1) on inflammatory responses of vascular smooth muscle cells (VSMCs), and investigate the mechanism. Methods: VSMCs were treated with lipopolysaccharide (LPS). Overexpression and knockdown of LSD1 in VSMCs were performed by transfecting with LSD1 overexpression plasmid and small interfering RNAs (siRNAs), respectively. Western blot and quantitative real-time polymerase chain reaction (qRTPCR) were used to measure protein and mRNA levels. Enzyme-linked immunosorbent (ELISA) assay was used to determine the levels of inflammatory cytokines. Results: Phosphorylation of LSD1 (p-LSD1) was significantly increased in LPS-induced VSMCs. Monocyte chemoattractant protein-1 and IL-6 levels were also increased by LPS, but attenuated by LSD1 knockdown in VSMCs. Activation of NF-κB was increased by LPS, but was also decreased by LSD1 knockdown. Level of methylated p65 (p65-me) in VSMCs was increased by treatment with SET7/9 (p65 methyltransferase), but this effect was attenuated by overexpression of LSD1. Besides, the increased levels of MCP-1 and IL-6 induced by overexpression of LSD1 were reversed by NF-κB signaling inhibitor, PDTC. Conclusion: LSD1 exacerbates LPS-induced inflammation of VSMCs through NF-κB activation via p65 demethylation, which indicates that LSD1 might be a potential target for the treatment of cardiovascular diseases. Keywords: Vascular smooth muscle cells, Lysine demethylase 1A, Phosphorylation, NF-κB, p65, Demethylation