潜在原因性eQTL影响阿托伐他汀内酯生成和肌毒性风险的代谢机制

Statin-induced myotoxicity (SIM) is one of the principal reasons for atorvastatin (AT) non-adherence and/or discontinuation, contributing to adverse cardiovascular outcomes. To date, the genetic mechanism of SIM is far from well-illustrated. Published data in vitro and in vivo indicated that atorvastatin lactone (ATL) is the key metabolite to induce myotoxicity. We therefore hypothesis that genetic variants increasing the formation of ATL can increase the risk to statin-induced myotoxicity. Based on the hypothesis, we have investigated the impact of candidate genetic variants on the formation of ATL. UGT1A1*6 and UGT2B7*2 were identified to be associated with the formation. However, they can only explain less than 14% variation in the formation of ATL. In the proposal, to further systematically discover novel functional genetic variants contributing to the formation of atorvastatin lactone and the risk to statin-induced myotoxicity, (1) a transcriptome-wide association study integrating genome wide variants and gene expression data will applied to identify expression quantitative trait loci (eQTL) associated with the formation of ATL and different bioinformatic tools will then be applied to reveal the potential causal impact of eQTLs on the formation of ATL. (2) Then, the effect of 30 eQTLs with the strongest causal relationship with the formation of ATL on the circulating explosure of ATL and the risk to SIM in patients with coronary artery disease (CAD) will be evaluated. (3) Last, the molecular mechanism of the eQTL with the highest risk to SIM on the metabolic network of ATL will be illustrated at three levels of patients with CAD, liver tissures, and cell models. The results of this study will give us insight into the metabolic mechanism of eQTLs on SIM and will help clinic optimize the therapy strategy of atorvastatin.

阿托伐他汀（AT）所致肌毒性是患者停药一个主要原因，常导致心血管事件，目前其遗传机制尚不清楚。研究表明阿托伐他汀内酯（ATL）是引起肌毒性的关键物质，我们认为影响ATL生成增多的基因变异可增加肌毒性风险。为了阐明这个问题，我们前期研究了多个代谢酶基因变异对ATL生成的影响，但这些基因变异解释个体差异不到14%。为了进一步系统地发现新的影响ATL生成和肌毒性风险的基因变异，本课题拟：①用人肝微粒体代谢模型，通过整合全基因组基因型和转录组数据进行基因表达数量性状位点（eQTL）分析，发现影响ATL生成的eQTL，并用不同生物信息学工具揭示其因果关系；②在冠心病患者中，明确关系最强的30个eQTL对ATL循环暴露的影响及对肌毒性的危险度；③靶向ATL代谢网络，从体内、肝组织和细胞模型三个层次阐明eQTL影响生成ATL的环节。研究结果有助阐明eQTL影响肌毒性的代谢机制和提高肌毒性风险预测能力。

阿托伐他汀（AT）所致肌毒性是患者停药一个主要原因，常导致心血管事件，目前其遗传机制尚不清楚。研究表明阿托伐他汀内酯（ATL）是引起肌毒性的关键物质，我们认为影响ATL生成增多的基因变异可增加肌毒性风险。为了阐明这个问题，本研究在中国冠心病随访队列人群中，以阿托伐他汀及其代谢物的血浆暴露量作为研究有效性和毒副作用的物质基础，分析其对临床终点事件的影响；进一步通过多阶段的基因组学分析，发现影响阿托伐他汀体内代谢的ADME基因变异。首先，在2448例冠心病随访队列中考察阿托伐他汀及代谢物血浆暴露量对主要心血管不良事件、再次缺血事件和死亡事件风险的影响；另在1219例冠心病队列人群中考察阿托伐他汀血浆暴露量对造影剂引起的急性肾损伤（CI-AKI）风险的影响。结果表明中等浓度的他汀可以在复合心血管事件方面达到相同或更好的效果，而高浓度的他汀及代谢物则显著增加患者死亡事件和CI-AKI事件的发生风险。进一步在857名冠心病患者中针对295个关键ADME基因进行基因组学分析，筛选出10个可能影响阿托伐他汀代谢的候选SNP位点。然后在另一228名冠心病队列中，验证候选SNP对阿托伐他汀血浆暴露量及代谢物转化率的影响，确定了UGT1A1*6基因多态性可以影响冠心病患者体内阿托伐他汀的代谢。综合两阶段共1085名冠心病患者，分析候选SNP基因分型与临床终点事件的关系。结果表明，UGT1A1*6基因多态性与死亡事件发生风险显著相关，UGT1A1*60基因多态性与MACE发生风险相关。结合上述结果，推测UGT1A1*6是通过影响阿托伐他汀在体内代谢过程进而影响临床终点事件的发生风险。最后，收集55名患者正常肝组织，制备肝微粒体酶，建立并优化阿托伐他汀在人肝微粒体的体外混合相代谢反应；分析候选SNP多态性是否对阿托伐他汀的代谢活化有影响。结果表明，阿托伐他汀在肝微粒体中的代谢与CYP3A、UGT1A1和UGT1A9酶活性呈正相关，UGT1A1*6与2-羟基阿托伐他汀的代谢显著相关。综上所述，本研究发现了他汀及代谢物的高暴露量会显著增加死亡事件、CI-AKI的的发生风险，中等浓度的他汀可以在复合心血管事件方面达到相同或更好的效果；并通过多阶段的研究系统发现了UGT1A1*6基因多态性能显著影响阿托伐他汀代谢。临床上可通过监测冠心病患者他汀及代谢物的血药浓度、检测基因分型为个体化治疗提供参考。

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