A3707 Myocardial microRNA-101 downregulates classical B1-adrenoreceptor signing cascade resulting in improving the cardiac function

Abstract

Objectives: We tested the hypothesis that the miR-101 down-regulates β1-AR expression and signaling resulting in improving the cardiac function. Methods: Bioinformatic analysis andhe dual luciferase assays was used to determine whether miR-101 target β1-AR mRNA. Through miR-101 mimic or inhibitor in H9C2 cell, the expression of β1-AR and protein kinase A (PKA), PKA phosphorylation (p-PKA) were tested by western blot. Quantitative real-time polymerase chain reaction (qRT-PCR) was employed to determine miR-101 expression profiles in the heart of spontaneously hypertensive rats (SHR) and age-matched Wistar-Kyoto (WKY) rats (n = 6, respectively). Rats were treated with miR-101 agomiR or antagomiR to build a miR-101-upregulated/ downregulated animal model. Cardiac function and HR were assessed by ultrasound diagnostic instrument, systolic blood pressure (SBP) was determined by non-invasive blood pressure analyzer, the expression of β1-AR, PKA, p-PKA protein were detected. Results: I The dual luciferase assays confomed that β1-AR is a direct target gene of miR-101. In vitro study, the expression level of β1-AR, PKA, p-PKA protein were decreased in H9C2 cell transfected with miR-101 mimic (p < 0.05). Meanwhile the expression level of β1-AR expression, PKA protein, p-PKA protein elevated in both H9C2 cell transfected with miR-101 inhibitor; In vivo study, the level of myocardial miR-101 expression were decreased in SHR rats compared to β1-AR (−/ − ) rats and WKY rats (p < 0.05). Elevated of β1-AR protein, PKA protein, p-PKA protein, cAMP level as well as BP, EF, FS in SHR rats was descresed by miR-101 mimic transfection. (p < 0.05). Conclusion: Myocardial microRNA-101 downregulates classical β1-adrenoreceptor signing cascade resulting in improving the cardiac function