Genetic Variants Associated with Tacrolimus Metabolism in Kidney Transplant Recipients

摘要 这款K01旨在实现Casey Dorr博士的目标，即成为一名独立的科学家，同时改进 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)发展生物信息学和统计建模的技能 教育和c)验证流行病学确定的基因变异。在未来，这些技能将被用于 分析大型遗传流行病学数据集，将其转换为其他药物和细胞的剂量模型 文化验证研究。多尔医生的咨询委员会由他的初级、流行病学和肾脏学领导， 导师，移植受者科学登记处副主任阿贾伊·伊斯拉尼博士。共同-- 导师帕马拉·雅各布森博士将就给药模型、药物基因组学和精确医学提供建议。其他 委员会成员包括：亨内平县医疗中心肾脏科主任Bertram Kasiske博士， 具有临床试验和结果研究专长的SRTR主任，以及Claudia Neuhauser博士和Balin博士 拥有统计建模和生物信息学专业知识的吴先生说。非裔美国人(AA)的同种异体移植更严重 比高加索人更能生存。对于治疗指数较小的药物，如他克莫司(Tac)，主要免疫 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排斥反应和过量用药 会导致中毒。此外，Tac血药浓度的患者内变异性(IPV)会导致较差的结果。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。三种常见的细胞色素P3A(药物代谢酶家族) 在我们对AA肾脏的大型全基因组关联研究中，最近发现了改变功能的变异 移植患者，但即使在移植后也只能解释Tac代谢总变异的50% 考虑了临床因素。该项目旨在了解Tac代谢的变化，这是一个模型 细胞色素P3A底物，在AA肾移植人群中。我假设基因中的低频率变异 细胞色素P3A基因(目标1)，或在与Tac相关的非细胞色素P3A基因(目标2)中，对决定 适当的Tac剂量。TAC是一种用于开发精确个性化给药的模型CYP3A药物 对肾移植受者的血药浓度进行常规监测.使用一种极端 血药浓度最高和最低的AA肾移植受者的表型抽样模型 (考虑到常见的遗传变异和临床因素)我们将在 CyP3A基因座，以及影响Tac转运、CyP3A表达或活性的基因 世代排序。已确定的变体将在电子计算机中进行分析，以确定功能变体。变种， 与Tac代谢相关的基因，将通过CRISPR技术工程进入培养细胞进行验证。 我们将使用细胞培养分析来从功能上验证变种。基因变异体的鉴定和验证 与Tac代谢相关的Tac将导致更好的Tac剂量模型，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.