PRMT4 inhibitor TP-064 inhibits the pro-inflammatory macrophage lipopolysaccharide response in vitro and ex vivo and induces peritonitis-associated neutrophilia in vivo

• Published in: Biochimica et biophysica acta. Molecular basis of disease Vol. 1867; no. 11; p. 166212
• Main Authors: Zhang, Yiheng, de Boer, Miriam, van der Wel, Ezra J., Van Eck, Miranda, Hoekstra, Menno
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01.11.2021
• Subjects: Animals; CARM1; Disease Models, Animal; Enzyme Inhibitors - pharmacology; Enzyme Inhibitors - therapeutic use; Gene expression; Humans; Lipopolysaccharides - administration & dosage; Lipopolysaccharides - immunology; LPS; Macrophage Activation - drug effects; Macrophages, Peritoneal - drug effects; Macrophages, Peritoneal - immunology; Macrophages, Peritoneal - metabolism; Male; Mice; Neutrophils - drug effects; Neutrophils - immunology; Peritonitis - blood; Peritonitis - chemically induced; Peritonitis - drug therapy; Peritonitis - immunology; Pro-inflammatory cytokines; Protein-Arginine N-Methyltransferases - antagonists & inhibitors; Protein-Arginine N-Methyltransferases - metabolism; RAW 264.7 Cells; Thioglycolates - administration & dosage; Thioglycolates - toxicity; Thioglycollate-induced peritonitis; Pro-inflammatory cytokines; Thioglycollate-induced peritonitis; Gene expression; CARM1; LPS
• ISSN: 0925-4439; 1879-260X
• DOI: 10.1016/j.bbadis.2021.166212

Previous in vitro studies have shown that protein arginine N-methyltransferase 4 (PRMT4) is a co-activator for an array of cellular activities, including NF-κB-regulated pro-inflammatory responses. Here we investigated the effect of PRMT4 inhibitor TP-064 treatment on macrophage inflammation in vitro and in vivo. Exposure of RAW 264.7 monocyte/macrophages to TP-064 was associated with a significant decrease in the production of pro-inflammatory cytokines upon a lipopolysaccharide challenge. Similarly, thioglycollate-elicited peritoneal cells isolated from wildtype mice treated with TP-064 showed lowered mRNA expression levels and cytokine production of pro-inflammatory mediators interleukin (IL)-1β, IL-6, IL-12p40, and tumor necrosis factor-α in response to lipopolysaccharide exposure. However, TP-064-treated mice exhibited an ongoing pro-inflammatory peritonitis after 5 days of thioglycollate exposure, as evident from a shift in the peritoneal macrophage polarization state from an anti-inflammatory LY6ClowCD206hi to a pro-inflammatory LY6ChiCD206low phenotype. In addition, TP-064-treated mice accumulated (activated) neutrophils within the peritoneum as well as in the blood (7-fold higher; P < 0.001) and major organs such as kidney and liver, without apparent tissue toxicity. TP-064 treatment downregulated hepatic mRNA expression levels of the PRMT4 target genes glucose-6-phosphatase catalytic subunit (−50%, P < 0.05) and the cyclin-dependent kinases 2 (−50%, P < 0.05) and 4 (−30%, P < 0.05), suggesting a direct transcriptional effect of PRMT4 also in hepatocytes. In conclusion, we have shown that the PRMT4 inhibitor TP-064 induces peritonitis-associated neutrophilia in vivo and inhibits the pro-inflammatory macrophage lipopolysaccharide response in vitro and ex vivo. Our findings suggest that TP-064 can possibly be applied as therapy in NF-κB-based inflammatory diseases. •PRMT4 is a potential regulator of monocyte/macrophage inflammation.•PRMT4 inhibitor TP-064 induces peritonitis-associated neutrophilia in vivo.•TP-064 inhibits LPS-induced pro-inflammatory cytokine secretion by macrophages.•TP-064 can possibly be applied as therapy in inflammatory diseases.