Genetic Variants Associated with Tacrolimus Metabolism in Kidney Transplant Recipients

摘要 本K 01旨在实现凯西多尔博士的目标，成为一名独立的科学家，同时提高 通过遗传流行病学的临床结果。Dorr博士将：A）发展遗传流行病学技能， 药物基因组学研究B）通过正式的生物信息学和统计建模培养技能 教育和C）流行病学鉴定的遗传变异。在未来，这些技能将用于 分析大型遗传流行病学数据集，将其转化为其他药物的剂量模型， 文化验证研究。多尔博士的咨询委员会由他的主要负责人，流行病学和肾脏病学， 导师，Ajay Israni博士，移植受体科学登记处（SRTR）的副主任。共- 导师Pamala Jacobson博士将在给药模型、药物基因组学和精准医学方面提供建议。其他 委员会成员包括：Hennepin县医疗中心肾病科主任Bertram Kasiske博士， 具有临床试验和结局研究专业知识的SRTR总监，以及Claudia诺伊豪泽和Baolin博士 吴先生，具有统计建模和生物信息学专业知识。非洲裔美国人（AAs）的同种异体移植物更差 比高加索人生存。对于治疗指数较窄的药物，如他克莫司（Tac）， 用于实体器官移植的抑制剂，剂量不足会导致同种异体移植物排斥反应和过量 导致中毒。此外，Tac血药浓度的患者内变异性（IPV）导致不良结局。通过 通过识别和验证改变药物代谢的遗传变异，临床医生可以选择最佳剂量， 降低药物不良反应和IPV的风险。三种常见的CYP 3A（药物代谢酶家族） 最近，我们在AA肾的大规模全基因组关联研究中发现了改变功能的变异 移植患者，但仅能解释~50%的总变化的Tac代谢后， 考虑临床因素。该项目旨在了解Tac代谢的变化， CYP 3A底物，AA肾移植人群。我假设，在基因组中的低频变异 CYP 3A基因（Aim 1）或与Tac相关的非CYP 3A基因（Aim 2）对于确定 合适的紫杉醇剂量Tac是一种CYP 3A模型药物，用于开发精确的个性化给药 在肾移植受者中，常规监测药物的血液浓度。使用极端 具有最高和最低Tac血液浓度的AA肾受体的表型采样模型 （考虑到常见的遗传变异和临床因素），我们将在 CYP 3A基因座，以及影响Tac转运、CYP 3A表达或活性的基因，使用下一个 世代排序将通过计算机模拟分析识别的变体，以识别功能变体。变体， 将通过CRISPR技术工程化到培养的细胞中来验证。 我们将使用细胞培养试验来功能性验证变体。遗传变异的鉴定和验证 与Tac代谢相关的基因将导致更好的Tac给药模型，旨在改善移植结果。

ABSTRACT This K01 aims to achieve Dr. Casey Dorr’s objective to become an independent scientist while improving clinical outcomes via genetic epidemiology. Dr. Dorr will: A) Develop genetic epidemiology skills for pharmacogenomics research B) Develop skills in bioinformatics and statistical modeling through formal education and C) Validate epidemiologically identified genetic variants. In the future, these skills will be used to analyze large genetic epidemiology data sets, translate them into dosing models for other drugs, and for cell culture validation studies. Dr. Dorr’s advisory committee is led by his primary, epidemiology and nephrology, mentor, Dr. Ajay Israni, the Deputy Director of the Scientific Registry of Transplant Recipients (SRTR). Co- mentor Dr. Pamala Jacobson will advise on dosing models, pharmacogenomics and precision medicine. Other committee members include: Dr. Bertram Kasiske, Chief of Nephrology at Hennepin County Medical Center, SRTR Director with clinical trials and outcomes research expertise, and Drs. Claudia Neuhauser and Baolin Wu, with statistical modeling and bioinformatics expertise. African Americans (AAs) have worse allograft survival than Caucasians. For narrow therapeutic index drugs, like tacrolimus (Tac), the primary immune suppressant used in solid organ transplantation, inadequate dosing results in allograft rejection and overdosing results in toxicity. Also, intrapatient variability (IPV) of Tac blood concentrations leads to poor outcomes. By identifying and validating the genetic variants that alter drug metabolism, clinicians can select optimal doses to reduce the risk for adverse drug reactions and IPV. Three common CYP3A (drug metabolism enzyme family) variants that alter function were recently identified in our large genome-wide association study of AA kidney transplant patients but only able to explained ~50% of the total variation in Tac metabolism even after accounting for clinical factors. This project aims to understand the variation in Tac metabolism, a model CYP3A substrate, in an AA kidney transplant population. I hypothesize that low-frequency variants in the CYP3A genes (Aim 1), or in non-CYP3A genes associated with Tac (Aim 2), are critical for determining the appropriate Tac dosage. Tac is a model CYP3A drug for developing personalized dosing in precision medicine as blood concentrations are routinely monitored in kidney transplant recipients. Using an extreme phenotype sampling model of AA renal recipients with the highest and lowest Tac blood concentrations (accounting for common genetic variants and clinical factors) we will identify low-frequency variants in the CYP3A gene locus, and genes that influence Tac transport, CYP3A expression or activity using next generation sequencing. Identified variants will be analyzed in silico to identify functional variants. Variants, associated with Tac metabolism, will be validated by engineering into cultured cells via CRISPR technology. We will use cell culture assays to functionally validate variants. Identification and validation of genetic variants associated with Tac metabolism will lead to better Tac dosing models aimed at improving transplant outcomes.