长链非编码RNA Lnc-TG调控APOA5致高甘油三酯血症促进动脉粥样硬化的机制研究

Recently, mendelian randomization data based on large cohort strongly suggest that hypertriglyceridemia (HTG) causes atherosclerotic cardiovascular disease , and so triglyceride (TG) level-lowering treatment in HTG is now more strongly recommended to reduce the cardiovascular residual risk(CRR) than has been indicated in published guidelines. Genome-wide association study(GWAS) and Exome sequencing have identified APOA5/A4/C3/A1 as the strongest signal,which increases serum TG level and confers risk for coronary heart disease. Our previous studies found that there was a novel long non-coding RNA, named Lnc-TG, expressing in HTG Rat liver and involving in APOA5 transcriptional regulation. However,the potential detailed molecular mechanism remained unknown. To test this hypothesis, we will make a comprehensive study by using HTG and atherosclerosis rat model along with rAAV injection, as well as EMSA,CHIP,RNA pull down, RIP and dul report method, to systematically determinate potential mechanism of Lnc-TG regulation APOA5 expression, resulting in HTG and accentuating arteriosclerosis. Our research may led to innovative lipid target therapies for reducing CRR.

基于大规模人群的的孟德尔随机化分析提示高甘油三酯（HTG）水平是动脉粥样硬化性疾病的致病因素，针对HTG的治疗也被指南推荐用于降低残余心血管风险(CRR)。全基因组关联分析（GWAS）和外显子组测序发现APOA5/A4/C3/A1基因簇是体内升高甘油三酯（TG）水平最强的信号并与冠心病显著相关。我们前期采用RNA-seq技术在高TG血症大鼠肝脏中发现新的非编码RNA Lnc-TG，预实验证实Lnc-TG可能通过调节APOA5表达致高TG血症，但其具体调控机制尚不清楚。本项目将在前期工作基础上利用大鼠高TG血症及动脉粥样硬化模型，通过重组腺相关病毒的干预，综合运用EMSA、CHIP、RNA pull down、RIP和报告基因等转录调控研究手段，充分阐明Lnc-TG调控APOA5表达致高TG血症，促进动脉粥样硬化的作用机制。本研究将为血脂治疗靶点开发和CRR管控提供全新思路。

长链非编码RNA(Long noncoding RNAs, lncRNAs)目前被认为具有重要而广泛的生物学功能，但lncRNAs作为重要的非编码RNA参与甘油三酯代谢的机制尚不清楚。我们通过转录组测序发掘和鉴定高甘油三酯血症大鼠肝脏中lnc19959.2(Lnc-TG)显著高表达。在体内和体外实验中证实lnc19959.2有特异性降低甘油三酯的作用。全基因组表达谱分析lnc19959.2敲除影响TG稳态基因表达。进一步的机制研究表明lnc19959.2通过泛素化转录抑制因子Purb表达来上调ApoA4基因表达，并特异性与hnRNPA2B1相互作用来分别下调Cpt1a、Tm7sf2和Gpam基因表达。在上游通路中，棕榈酸通过CCAAT/增强子结合蛋白β(Cebpb)来促进与lnc19959.2启动子的结合提高lnc19959.2的转录活性。我们的发现为lncRNA调节甘油三酯稳态的新层面的复杂调控提供了新见解。