Genetic Pathways of Human Cytomegalovirus Drug Resistance

项目摘要 毒性和耐药性限制了巨细胞病毒抗病毒治疗的疗效 巨细胞病毒(CMV)病在免疫抑制的宿主，如癌症和移植受者。 目前的治疗方法包括DNA聚合酶抑制剂更昔洛韦、磷甲酸钠和西多福韦。 终止酶抑制剂来特莫韦最近被批准用于预防，UL97 激酶抑制剂maribavir正在进行晚期试验，作为替代疗法。在临床实践中， CMV耐药性不能通过病毒分离株的直接表型测试来诊断， 而是依赖于检测到的病毒突变和 相关耐药表型。这项研究的持久目标是 探讨CMV耐药的遗传机制以提高临床疗效 诊断和替代疗法的发展。许多耐药突变和 巨细胞病毒UL97激酶、UL54 DNA聚合酶和UL56/UL89/UL51基因的多态性 终止酶基因已经并将继续进行表型，具有诊断意义 在每个项目期间发现重要的新抗性基因座。技术 重组表型和全基因组深度测序的研究进展 为这项研究提供便利。在即将到来的项目期间，新的重点领域包括 药物暴露后选择的已知基因突变的特征 抗病毒靶点，以及基线病毒株变异对药物的影响分析 敏感度。具体目标是(1)继续评价进化和表型 在体外或体内暴露于抗病毒化合物后发生的CMV突变 和组合；(2)评估已识别的遗传变化的表型意义 通过对已知抗病毒靶基因以外的病毒全基因组深度测序， 以及(3)确定基线病毒株对药物敏感性表型的影响 可选择的病毒克隆和宿主细胞的特征。

Project Summary Toxicity and drug resistance limit the efficacy of antiviral therapy for cytomegalovirus (CMV) disease in immunosuppressed hosts such as cancer and transplant recipients. Current therapy includes DNA polymerase inhibitors ganciclovir, foscarnet and cidofovir. The terminase inhibitor letermovir was recently approved for prophylaxis, and the UL97 kinase inhibitor maribavir is in late stage trial as alternative therapy. In clinical practice, CMV drug resistance cannot be diagnosed by direct phenotypic testing of viral isolates, and instead is dependent on an accurate correlation of detected viral mutations and associated resistance phenotypes. The enduring objective of this research is to determine the genetic mechanisms of CMV drug resistance in order to improve clinical diagnosis and the development of alternate therapies. Many resistance mutations and polymorphisms in the CMV UL97 kinase, UL54 DNA polymerase and UL56/UL89/UL51 terminase genes have been and continue to be phenotyped, with diagnostically important new resistance loci being identified during each project period. Technical advances in recombinant phenotyping and whole genome deep sequencing are facilitating this research. In the upcoming project period, new focus areas include the characterization of mutations selected after drug exposure in genes outside of known antiviral targets, and analysis of the effects of baseline viral strain variation on drug susceptibility. Specific aims are (1) continued evaluation of the evolution and phenotypes of CMV mutations that develop after in vitro or in vivo exposure to antiviral compounds and combinations; (2) evaluate the phenotypic significance of genetic changes identified by viral whole genome deep sequencing that are outside of known antiviral target genes, and (3) determine the impact of baseline viral strain on drug susceptibility phenotypes by characterization of alternative viral clones and host cells.