Coactivator-associated arginine methyltransferase 1 targeted by miR-15a regulates inflammation in acute coronary syndrome

Objective Coactivator-associated arginine methyltransferase 1 (CARM1) is essential for the activation of a subset of NF-кB-dependent genes, which code the chemokines triggering plaque vulnerability. Unstable atherosclerotic plaques lead to the onset of acute coronary syndrome (ACS). Therefore, we aimed to investigate whether CARM1 is involved in the pathogenesis of ACS and ascertain the regulatory mechanism of CARM1 expression at posttranscriptional level. Methods Peripheral blood mononuclear cells (PBMCs) were isolated from peripheral blood of 19 patients with ACS and 22 subjects with risk factors for coronary heart disease. Gene expression was determined by quantitative real-time PCR and Western blot. The effects of CARM1 and miR-15a on their target genes expression were assessed by gain-of-function and loss-of-function approaches. Results PBMCs from patients with ACS showed higher levels of CARM1 mRNA and protein expression. The levels of CARM1 mRNA were positively correlated with three chemokines including interferon-inducible protein-10 (IP-10), monocyte chemoattractant protein 1 (MCP-1), and interleukin-8 (IL-8) in PBMCs ( CARM1 and IP-10 : r = 0.55, P = 0.008; CARM1 and MCP-1 : r = 0.64, P = 0.002; CARM1 and IL-8 : r = 0.55, P = 0.008). Moreover, CARM1 regulated the transcription of these chemokines in human embryonic kidney 293T (HEK293T) cells. We also found that the levels of miR-15a were decreased by 37% in patients with ACS and miR-15a modulated CARM1 expression through targeted binding to CARM1 3′-UTR. Conclusion The present study demonstrated that CARM1 targeted by miR-15a played an important role in chemokine activation in the pathogenesis of ACS.