The early genetic pathway(s) triggering the pathogenesis of coronary artery disease (CAD) and myocardial infarction (MI) remain largely unknown. Here, we describe an autosomal dominant form of CAD/MI ( adCAD1 ) that is caused by the deletion of seven amino acids in transcription factor MEF2A. The deletion disrupts nuclear localization of MEF2A, reduces MEF2A-mediated transcription activation, and abolishes synergistic activation by MEF2A and by the transcription factor GATA-1 through a dominant-negative mechanism. The MEF2A protein demonstrates strong expression in the endothelium of coronary arteries. These results identify a pathogenic gene for a familial vascular disease with features of CAD and implicate the MEF2A signaling pathway in the pathogenesis of CAD/MI.

Endoplasmic reticulum stress is an evolutionarily conserved cell stress response associated with numerous diseases, including cardiac hypertrophy and heart failure. The major endoplasmic reticulum stress signaling pathway causing cardiac hypertrophy involves endoplasmic reticulum stress sensor PERK (protein kinase-like kinase) and eIF2α-ATF4-CHOP signaling. Here, we describe a non-canonical, AGGF1-mediated regulatory system for endoplasmic reticulum stress signaling associated with increased p-eIF2α and ATF4 and decreased sXBP1 and CHOP. Specifically, we see a reduced AGGF1 level consistently associated with induction of endoplasmic reticulum stress signaling in mouse models and human patients with heart failure. Mechanistically, AGGF1 regulates endoplasmic reticulum stress signaling by inhibiting ERK1/2 activation, which reduces the level of transcriptional repressor ZEB1, leading to induced expression of miR-183-5p. miR-183-5p post-transcriptionally downregulates CHOP and inhibits endoplasmic reticulum stress-induced apoptosis. AGGF1 protein therapy and miR-183-5p regulate endoplasmic reticulum stress signaling and block endoplasmic reticulum stress-induced apoptosis, cardiac hypertrophy, and heart failure, providing an attractive paradigm for treatment of cardiac hypertrophy and heart failure.

Objective— Recent genome-wide association studies have identified 4 SNPs on chromosome 9p21 associated with CAD (rs10757274 and rs2383206) and myocardial infarction (MI: rs2383207 and rs10757278) in White populations in Northern Europe and North America. We aimed to determine whether this locus confers significant susceptibility to CAD in a South Korean population, and thus cross-race susceptibility to CAD. Methods and Results— We performed a case-control association study with 611 unrelated CAD patients and 294 normal controls from South Korea. Allelic associations of SNPs and SNP haplotypes with CAD were evaluated. Multivariate logistic regression analysis was used to adjust effects of clinical covariates. We found that 4 SNPs on chromosome 9p21 were associated with susceptibility to CAD in a South Korean population. The association remained significant after adjusting for significant clinical covariates ( P =0.001 to 0.024). We identified one risk haplotype (GGGG; P =0.017) and one protective haplotype (AAAA; P =0.007) for development of CAD. Further analysis suggested that the SNPs probably confer susceptibility to CAD in a dominance model (covariates-adjusted P =0.001 to 0.024; OR=2.37 to 1.54). This represents the first study that expands association of these 9p21 SNPs with CAD beyond White populations. Conclusion— Chromosome 9p21 is an important susceptibility locus that confers high cross-race risk for development of CAD.

In the initiation and maintenance of arrhythmia, inflammatory processes play an important role. IL-2 is a pro-inflammatory factor which is associated with the morbidity of arrhythmias, however, how IL-2 affects the cardiac electrophysiology is still unknown. In the present study, we observed the effect of IL-2 by qRT-PCR on the transcription of ion channel genes including SCN2A, SCN3A, SCN4A, SCN5A, SCN9A, SCN10A, SCN1B, SCN2B, SCN3B, KCNN1, KCNJ5, KCNE1, KCNE2, KCNE3, KCND3, KCNQ1, KCNA5, KCNH2 and CACNA1C. Western blot assays and electrophysiological studies were performed to demonstrate the effect of IL-2 on the translation of SCN3B/scn3b and sodium currents. The results showed that transcriptional level of SCN3B was up-regulated significantly in Hela cells (3.28-fold, p = 0.022 compared with the control group). Consistent results were verified in HL-1 cells (3.73-fold, p = 0.012 compared with the control group). The result of electrophysiological studies showed that sodium current density increased significantly in cells which treated by IL-2 and the effect of IL-2 on sodium currents was independent of SCN3B (1.4 folds, p = 0.023). Western blot analysis showed IL-2 lead to the significantly increasing of p53 and scn3b (2.1 folds, p = 0.021 for p53; 3.1 folds, p = 0.023 for scn3b) in HL-1 cells. Consistent results were showed in HEK293 cells using qRT-PCR analysis (1.43 folds for P53, p = 0.022; 1.57 folds for SCN3B, p = 0.05). The present study suggested that IL-2, may play role in the arrhythmia by regulating the expression of SCN3B and sodium current density.