Studies on the Epigenetic and Transcriptional Regulation of LSD1 in Inflammatory Response

Abstract

The inflammatory response is an essential host defense mechanism against invading pathogens. NF-κB signaling plays a key role in regulating the inflammatory response, and misregulation of NF-κB signaling is involved in cancer and autoimmune disease. Although protein kinase C (PKC) signaling is shown to be crucial for the activation of the inflammatory response, the molecular mechanism of activation of the inflammatory response by PKC remains unclear. Here, I find that PKCα is translocated into the nucleus in response to inflammatory signal and directly phosphorylates lysine specific demethylase 1 (LSD1) in the nucleus. Lipopolysaccharide (LPS)-induced LSD1 phosphorylation by PKCα is required for its interaction with p65, and phosphorylated LSD1 facilitates demethylation of p65 leading to enhanced p65 protein stability. Genome-wide analysis reveals that LPS-induced LSD1 phosphorylation leads to activation of NF-κB target genes involved in sepsis. Importantly, Lsd1SA/SA mice with ablation of LSD1 phosphorylation show attenuated LPS-induced lung inflammatory injury and sepsis-induced mortality with greater survival rates than wild-type (WT) mice. Together, our data indicate that targeting PKCα signaling with its downstream LSD1 could be potentially powerful therapeutic strategy for inflammatory diseases such as sepsis.