SIRT2 regulates macrophage chemotaxis by de-modifying histone H4K8 lactylation

Abstract

Objective·To explore the regulatory role of silent information regulator 2 (SIRT2) in modulating the immune phenotype of macrophages after infection by removing the lactylation at H4K8 site of histone and the corresponding mechanism.Methods·Human THP-1 leukemia cells were induced by phorbol 12-myristate 13-acetate (PMA) and stimulated by lipopolysaccharide (LPS) to establish a macrophage infection model. Macrophages without LPS treatment (pTHP-1) were set as the control (CTRL) group, and macrophages with LPS treatment were set as the infected (LPS) group. Western blotting was used to detect the level of histone modification and SIRT2 protein in macrophages. RT-qPCR was used to detect the expression level of glycolytic key enzymes [phosphofructokinase liver type (PFKL), lactate dehydrogenase A (LDHA)] and modulators genes hypoxia inducible factor 1α (HIF-1α), and the expression level of Sirtuin genes and HDAC genes between the two groups. Transwell was used to detect the ability of macrophage chemotaxis. Lentivirus packaging and cell infection were used to construct SIRT2 overexpression cell line. The interaction analysis method of RNA sequencing (RNA-seq) and chromatin immunoprecipitation sequencing (ChIP-seq) was used to analyze the difference and pathway enrichment of the genes specifically bound to H4K8 lactylation (H4K8la).Results·Compared to the CTRL group, macrophage glycolysis was upregulated and the level of H4K8la was significantly increased in the LPS group (P0.05). The interactive analysis of ChIP-seq and RNA-seq revealed that chemotaxis-related genes were regulated by H4K8la, and macrophage chemotaxis ability significantly decreased after the overexpression of SIRT2 and downregulation of H4K8la (P<0.05).Conclusion·SIRT2 can change the expression of target genes related to chemotaxis by removing H4K8la modification, thereby reducing the chemotaxis ability of macrophages. Targeting SIRT2 and H4K8la modification may help control inflammation mediated by macrophages.

Keywords

• macrophage
• chemotaxis
• lactylation
• post-translational modification
• silent information regulator 2 (sirt2)