Soluble epoxide hydrolase inhibitors might prevent ischemic arrhythmias via microRNA-1 repression in primary neonatal mouse ventricular myocytes

Abstract

Ischemic arrhythmias are the main causes of sudden cardiac death. It has been reported that soluble epoxide hydrolase inhibitors (sEHis) could prevent arrhythmias; however, the underlying molecular mechanisms remain unclear. In recent years, the proarrhythmic role of microRNA-1 (miR-1) has been investigated. This study aimed to elucidate whether sEHis prevented ischemic arrhythmias by suppressing miR-1. The primary neonatal mouse ventricular myocyte model of miR-1 overexpression was established by incubating with agonist microONTM mmu-miR-1a-3p agomir (DAEDstain Dye) (agomiR-1). The sEHi, trans-4-[4-(3-adamantan-1-yl-ureido)-cyclohexyloxy]-benzoic acid (t-AUCB), was administered following miR-1 overexpression. Quantitative real-time PCR (qPCR) and western blotting were used to test alterations in the expression of miR-1 and its target mRNAs GJA1 and KCNJ2 and their respective encoded proteins connexin 43 (Cx43) and the K channel subunit (Kir2.1). The whole-cell patch-clamp technique was used to record the alterations of the inward rectifying K current (I). Compared with the control group, miR-1 levels were significantly increased in the agomiR-1 group (p < 0.05), which suggested the successful construction of the miR-1 overexpression model. Compared with the control group, the levels of GJA1 and KCNJ2 mRNAs and Cx43 and Kir2.1 proteins in the agomiR-1 group were significantly decreased, and I was significantly impaired (all p < 0.05). The miR-1 levels were dose-dependently decreased by t-AUCB, whereas t-AUCB dose-dependently increased the levels of GJA1 and KCNJ2 mRNAs and Cx43 and Kir2.1 proteins. Furthermore, t-AUCB restored the impaired I (all p < 0.05). In conclusion, the sEHi t-AUCB has the ability to down-regulate proarrhythmic miR-1 and up-regulate its target genes and proteins, eventually restoring I.

Soluble epoxide hydrolase inhibitors, t-AUCB, regulated microRNA-1 and its target genes in myocardial infarction mice

“…Here, we demonstrated for the first time, that the sEHi t-AUCB dose-dependently suppressed miR-1 upregulation in ischemic myocardium, which might be one of the mechanisms underlying the anti-arrhythmic effect of sEHi. Consistently, our previous in vitro whole-cell patch-clamp recording demonstrated that the current density of I k1 was markedly decreased in miR-1 overexpression model of neonatal cardiac myocytes [ 24 ]. The decreased I k1 was an important proarrhythmic factor in cardiac myocytes..…”

“…Most importantly, we found that t-AUCB suppressed miR-1 overexpression and restored the impaired target mRNA and protein, which further suggested that the inverse relationship between sEHIs and miR-1 expression. Moreover, we previous studies also showed the beneficial effects of sEHIs on the expression of miR-1 and its target arrhythmia-related genes in neonatal cardiac myocytes [ 24 ].…”

Potential roles of microRNA-1 and microRNA-133 in cardiovascular disease

“…Soluble epoxide hydrolase inhibitor (sEHi) increases EET concentration by inhibiting their degradation (Duflot et al, 2014). EETs play an antiarrhythmic role by downregulating abnormally upregulated miR-1 and miR-133 in the myocardium after myocardial infarction (Gui et al, 2018;Liu et al, 2017), but the specific mechanism remains unclear ( Fig. 1).…”

Vascular smooth muscle cell phenotypic transition regulates gap junctions of cardiomyocyte

“…There is an emerging role of microRNA (miRNA) in connexins regulation of cardiomyocytes [15,16]. MiRNAs are short nucleotide sequences that bind to the 3′-untranslated region of mRNA, thereby regulating gene expression at the post-transcriptional level by inhibiting the translation of a protein or by promoting mRNA degradation.…”