Atherosclerotic cardiovascular disease is a metabolic and inflammatory disorder. In vitro studies have suggested that protein arginine methyltransferase 4 (PRMT4) may act as a transcriptional... Show moreAtherosclerotic cardiovascular disease is a metabolic and inflammatory disorder. In vitro studies have suggested that protein arginine methyltransferase 4 (PRMT4) may act as a transcriptional coactivator to modulate inflammatory and metabolic processes. Here we investigated the potential anti-atherogenic effect of PRMT4 inhibitor TP-064 in vivo.\nMale apolipoprotein E knockout mice fed a high cholesterol/high fat Western-type diet were intraperitoneally injected three times a week with 2.5 mg/kg (low dose) or 10 mg/kg (high dose) TP-064 or with DMSO control.\nTP-064 induced a dose-dependent decrease in lipopolysaccharide-induced ex vivo blood monocyte Tnfα secretion (p < 0.05 for trend) in the context of unchanged blood monocyte concentrations and neutrophilia induction (p < 0.01 for trend). A dose-dependent decrease in gonadal white adipose tissue expression levels of PPARγ target genes was detected, which translated into a reduced body weight gain after high dose TP-064 treatment (p < 0.05). TP-064 treatment also dose-dependently downregulated gene expression of the glycogen metabolism related protein G6pc in the liver (p < 0.001 for trend). In addition, a trend towards lower plasma insulin and higher blood glucose levels was observed, which was paralleled by a reduction in hepatic mRNA expression levels of the insulin-responsive genes Fasn (-55%; p < 0.001) and Gck (-47%; p < 0.001) in high dose-treated mice. Plasma triglyceride levels were reduced by high dose TP-064 treatment (-30%; p < 0.05). However, no change was observed in the size or composition of aortic root atherosclerotic lesions.\nThe PRMT4 inhibitor TP-064 impacts both inflammatory and metabolic processes without changing atherosclerosis susceptibility of male apolipoprotein E knockout mice. Show less
Zhang, Y.; Boer, M. de; Wel, E.J. van der; Eck, M. van; Hoekstra, M. 2021
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.... Show morePrevious 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. Show less