Tylden Garth D, Hirsch Hans H, Rinaldo Christine Hanssen
Department of Microbiology and Infection Control, University Hospital of North Norway, Tromsø, Norway Department of Medical Biology, UiT The Arctic University of Norway, Tromsø, Norway.
Transplantation & Clinical Virology, Department Biomedicine (Haus Petersplatz), University of Basel, Basel, Switzerland Infectious Diseases & Hospital Epidemiology, University Hospital Basel, Basel, Switzerland.
Antimicrob Agents Chemother. 2015;59(6):3306-16. doi: 10.1128/AAC.00238-15. Epub 2015 Mar 23.
BK polyomavirus (BKPyV)-associated hemorrhagic cystitis (PyVHC) complicates 5 to 15% of allogeneic hematopoietic stem cell transplantations. Targeted antivirals are still unavailable. Brincidofovir (BCV; previously CMX001) has shown inhibitory activity against diverse viruses, including BKPyV in a primary human renal tubule cell culture model of polyomavirus-associated nephropathy. We investigated the effects of BCV in BKPyV-infected and uninfected primary human urothelial cells (HUCs), the target cells of BKPyV in PyVHC. The BCV concentrations causing 50 and 90% reductions (EC50 and EC90) in the number of intracellular BKPyV genome equivalents per cell (icBKPyV) were 0.27 μM and 0.59 μM, respectively. At 0.63 μM, BCV reduced viral late gene expression by 90% and halted progeny release. Preinfection treatment for only 24 h reduced icBKPyV similarly to treatment from 2 to 72 h postinfection, while combined pre- and postinfection treatment suppressed icBKPyV completely. After investigating BCV's effects on HUC viability, mean selectivity indices at 50 and 90% inhibition (SI50 and SI90) calculated for cellular DNA replication were 2.7 and 2.9, respectively, those for mitochondrial activity were 8.9 and 10.4, those for total ATP were 8.6 and 8.2, and those for membrane integrity were 25.9 and 16.7. The antiviral and cytostatic effects, but less so the cytotoxic effects, were inversely related to cell density. The cytotoxic effects at concentrations of ≥10 μM were rapid and likely related to BCV's lipid moiety. After carefully defining the antiviral, cytostatic, and cytotoxic properties of BCV in HUCs, we conclude that a preemptive or prophylactic approach in PyVHC is likely to give the best results.
BK多瘤病毒（BKPyV）相关的出血性膀胱炎（PyVHC）在5%至15%的异基因造血干细胞移植中会出现并发症。目前仍没有针对性的抗病毒药物。布林西多福韦（BCV；以前称为CMX001）在多瘤病毒相关肾病的原代人肾小管细胞培养模型中已显示出对包括BKPyV在内的多种病毒具有抑制活性。我们研究了BCV对BKPyV感染和未感染的原代人尿路上皮细胞（HUCs）的影响，HUCs是PyVHC中BKPyV的靶细胞。使每个细胞内BKPyV基因组当量（icBKPyV）数量减少50%和90%（EC50和EC90）的BCV浓度分别为0.27μM和0.59μM。在0.63μM时，BCV使病毒晚期基因表达降低90%并阻止子代释放。仅感染前处理24小时对icBKPyV的降低作用与感染后2至72小时的处理相似，而感染前和感染后联合处理则完全抑制icBKPyV。在研究了BCV对HUC活力的影响后，针对细胞DNA复制计算的50%和90%抑制率（SI50和SI90）时的平均选择性指数分别为2.7和2.9，针对线粒体活性的分别为8.9和10.4，针对总ATP的分别为8.6和8.2，针对膜完整性的分别为25.9和16.7。抗病毒和细胞生长抑制作用，但细胞毒性作用较小，与细胞密度呈负相关。浓度≥10μM时的细胞毒性作用迅速，可能与BCV的脂质部分有关。在仔细确定BCV在HUCs中的抗病毒、细胞生长抑制和细胞毒性特性后，我们得出结论，对PyVHC采取抢先或预防性方法可能会取得最佳效果。
