miR-29调控心肌细胞葡萄糖代谢在心室重构中的作用机制

The metabolic disorders of cardiomyocytes are an important etiology of heart failure. Previous studies have found that: 1) compared to normal myocardium, atrophic myocardium presents with reduced glucose uptake rates and different pattern of protein expression involved in glucose metabolism; 2) the diabetic biomarker miR-29 is significantly over-expressed in the remodeled myocardium. Basing on these issues, we formulate the hypothesis: miR-29 play an important role in the process of ventricular remodeling through regulating the glucose metabolism. In the present study, we will employ the bioinformatics and dual luciferase reporter assay to identify potential miR-29 target genes related to the process of ventricular remodeling Subsequently, we will evaluate the effect of miR-29 over-expression/inhibition on target mRNA, signal pathway, cellular morphology and glucose uptake in the primary culture of the cardiomyocytes of neonatal rats; furthermore, we will investigate the mechanism of miR-29 being related to the process of ventricular remodeling through the regulation of glucose metabolism in animal models. This study will provide some theoretical support for the clinical use of miR-29 as a diagnostic and therapeutic biomarker in the management of heart failure.

心肌细胞代谢紊乱是导致心力衰竭的重要病因。前期研究发现：1）与正常心肌相比，萎缩心肌细胞对葡萄糖摄取显著下降，多种葡萄糖代谢相关蛋白差异性表达；2）糖尿病分子标记物miR-29在重构心肌中表达显著增加。由此推测：miR-29可能通过调控心肌细胞葡萄糖代谢参与心室重构的发生发展。本项目应用生物信息学技术，双荧光酶报告基因法初步筛选并验证与心室重构相关的miR-29靶基因。以体外培养的原代新生大鼠心肌细胞为研究对象，观察心肌细胞中miR-29沉默和过表达对miR-29候选靶基因、信号通路、心肌细胞形态及葡萄糖摄取率等指标的影响，探讨miR-29通过调控心肌细胞葡萄糖代谢参与心室重构的机制，并以动物模型加以验证，为miR-29成为心衰诊治新靶点提供理论依据。

心肌细胞代谢紊乱是导致心力衰竭的重要病因，前期研究显示miR-29通过调节葡萄糖代谢在糖尿病心血管并发症的发生发展过程中起重要作用，我们推测：miR-29可能通过调控心肌细胞葡萄糖代谢参与调节心室重构。本项目应用生物信息学技术，筛选与心室重构相关的miR-29预测靶基因；探索并确定以10-6umol/L血管紧张素-II（Ang-II）诱导大鼠心肌细胞系H9C2肥大模型，观察到以Ang-II诱导的肥大H9C2细胞中，miR-29及其与葡萄糖代谢相关预测靶基因INSIG1、PIK3R3、COX4、G6PC、GLUT1以及胰岛素信号通路分子AKT、mTORC1等表达上调；在经Ang-II处理的CHOK1和Movas细胞中，miR-29表达加强；在牵张力诱导小鼠心肌细胞系HL-1肥大模型中，与细胞肥大相关信号通路的重要分子Akt、ERK1/2磷酸化水平提高；我们还发现miR-29强化血管紧张素II受体-1（AT1R）激活的细胞内钙转移。在动物试验水平，我们建立腹主动脉结扎术诱导大鼠心室肥厚模型，并将在组织和器官水平进一步验证miR-29及上述靶基因与心室肥厚型重构的关系。我们的研究表明，在机械牵张力刺激或药物诱导心肌细胞肥大模型中，miR-29均发挥重要作用，参与心肌细胞葡萄糖代谢是机制之一。本研究为miR-29作为心衰生物标志物和诊治靶点提供了一定理论依据。