基于基因组学和代谢组学的硫嘌呤类药物个体化给药

Thiopurine drugs（Azathioprine/6-mercaptopurine）has been widely used as immunosuppressive agents for inducing and maintaining remission of inflammatory bowel disease with the efficacy rate of 55~70%. However, thiopurine drugs have to be withdrawn in 10~30% patients due to serious side effects such as hematotoxicity and hepatotoxicity. Early study results from our lab revealed that the activity of HPRT, the genetic polymorphisms concerned TPMT、MRP4 ,and the concentration of active metabolite 6TGNs were correlated with AZA/6MP pharmacokinetics and pharmacodynamics. But all the results so far cannot fully elucidate the great interindividual variations in thiopurines therapeutic effect and adverse drug reactions（AE）, which suggests that more genetic factors need to be screened and both AZA/6MP metabolites and patients' inherent small molecule metabolite profiles should be concerned. Therefore, the high-throughput mass spectrometry genotyping technology will be adopted to screen the polymorphisms of genetic factors including metabolic enzymes, transporters and nuclear receptors which may influence thiopurines pharmacokinetics and pharmacodynamics in present proposal. Meanwhile, the difference of interindividual post dose metabolic profiles between response and resistance groups, AE and tolerance groups will be detected by metabonomics analysis to discover predictive biomarkers. Finally, significant SNPs predictors and metabolites biomarkers will be adopted to develop a multiple liner regression model for predicting the therapeutic dose of AZA/6MP, and verifying this model in clinic as guidance for personalized medicine.

硫嘌呤类药物(AZA/6MP)是炎性肠病（IBD）经典维持药物，然而治疗窗窄和药动学/药效学个体差异大困扰着临床用药。本课题组前期数据表明，AZA/6MP代谢酶HPRT活性、TPMT、MRP4多态性及6TGN代谢产物浓度与其药动学和药效学有一定相关性，但无法全部解释此类药物药动学和不良反应个体差异原因，这提示需要更广泛基因组学筛查以及药物与内源代谢组分析。因此，本研究拟在前期工作基础上，利用高通量质谱基因分型技术，对AZA/6MP药动学和药效学相关的代谢酶、转运体及核受体遗传多态性，进行更全面基因筛查。同时，利用代谢组学技术分析IBD患者服药后有效组与复发组、不良反应组与耐受组的差异性内源代谢谱，找出具有临床意义的生物标志物，最终结合相关基因的差异性SNP建立AZA/6MP剂量预测方程并通过临床应用进行验证，从而指导其个体化用药。

硫嘌呤类药物(AZA/6MP)是炎性肠病(IBD)经典维持治疗药物，但其治疗窗窄和个体差异大困扰着临床用药。本课题组前期数据表明，AZA/6MP代谢酶TPMT、转运体MRP4多态性及6TGN代谢产物浓度与其药动学和药效学有一定相关性，但无法全部解释此类药物药动学和不良反应个体差异。本研究在前期工作基础上，利用高通量质谱基因分型技术，对AZA/6MP药物相关的代谢酶、转运体以及DNA错配修复通路相关基因遗传多态性，进行更全面筛查。同时，本研究利用代谢组学方法拓展考察红细胞中硫嘌呤三种代谢产物TGTP/TGDP/TGMP以及全血DNA中DNA-TG浓度与药物反应关系，寻找出具有临床意义的生物标志物，为指导其个体化用药提供依据。.研究首次在中国人群发现NUDT15 R139C与硫嘌呤药物所致白细胞减少症存在显著相关性，并通过随机对照试验证明基于NUDT15 R139C基因型指导的个体给药剂量方案相比传统给药方案能显著的降低硫嘌呤药物不良反应发生率,同时不影响该类药物治疗效果。目前，该基因型检测已被纳入《炎症性肠病诊断与治疗的共识意见》。此外，本研究率先发现IBD患者DNA-TG浓度与硫嘌呤药物所致不良反应存在显著相关性，基于DNA-TG危险浓度阈值333.8 fmol/ug DNA预测硫嘌呤所致白细胞减少症敏感性高达90.6%，特异性为59.1%，该结果提示对于中国IBD患者DNA-TG比6TGN更适合作为预测该类不良反应的生物标志物；基于 NUDT15 rs186364861，MOCOS rs73430958，AOX1 rs12993144，NEIL2 rs809206 的多重线性回归模型可解释27.8%的DNA-TG药动学差异，表明该模型能够较有效的预测DNA-TG的浓度，并对白细胞减少症的发生有一定的预测作用。