Department of Biotechnology, INIA, Ctra. Coruña Km. 7.5, 28040 Madrid, Spain.
Viruses. 2018 Feb 23;10(2):91. doi: 10.3390/v10020091.
Flaviviruses are relevant animal and human pathogens that include West Nile virus (WNV), Japanese encephalitis virus, dengue virus, or Zika virus, among others. Currently, no licensed therapy is available to fight flaviviral infections. Protein kinases C (PKCs) constitute a family of multifunctional lipid-dependent isoenzymes that regulate a wide variety of cellular processes (apoptosis, differentiation, proliferation, cellular transformation, motility, adhesion, etc.) being currently considered at the front line of drug development for the treatment of diverse human disorders. PKCs have also been implicated in different steps during viral replication; however, nowadays, results regarding their role in flavivirus replication are controversial. Here we demonstrate that calphostin C and chelerythrine, two broad-PKC inhibitors that target conventional, novel and atypical PKCs, significantly inhibit WNV multiplication in cell culture without affecting cell viability. A reduction of viral yields was observed in treated cells when compared with mock-treated cells. Likewise, immunofluorescence detection of viral enveloped E protein was reduced in treated cells, as was the amount of viral RNA released to the supernatant, mainly in those treated with chelerythrine. On the other hand, two PKC inhibitors specific for conventional and novel isoforms (staurosporine and enzastaurine) did not show any significant effect in WNV multiplication. These results suggested that PKCs, more probably atypical PKCs, are likely involved in WNV multiplication, although both broad-spectrum tested drugs seem to act through different mechanisms, and point to them as potential antiviral candidates for WNV, as well as for other related flaviviruses.
黄病毒是重要的动物和人类病原体，包括西尼罗河病毒（WNV）、日本脑炎病毒、登革热病毒、寨卡病毒等。目前，尚无针对黄病毒感染的许可疗法。蛋白激酶 C（PKCs）是一个多功能的脂依赖性同工酶家族，可调节多种细胞过程（凋亡、分化、增殖、细胞转化、运动、黏附等），目前被认为是治疗各种人类疾病的药物开发的前沿。PKCs 也被牵连到病毒复制的不同阶段；然而，目前关于它们在黄病毒复制中的作用的结果存在争议。在这里，我们证明 calphostin C 和 chelerythrine，两种广谱 PKC 抑制剂，靶向经典、新型和非典型 PKCs，可显著抑制细胞培养中的 WNV 增殖，而不影响细胞活力。与对照细胞相比，处理细胞中的病毒产量减少。同样，用处理细胞进行免疫荧光检测时，病毒包膜 E 蛋白的表达减少，上清液中释放的病毒 RNA 量也减少，主要是用 chelerythrine 处理的细胞。另一方面，两种针对经典和新型同工酶的 PKC 抑制剂（staurosporine 和 enzastaurine）在 WNV 增殖中没有显示出任何显著效果。这些结果表明，PKCs，更可能是非典型 PKCs，可能参与了 WNV 的增殖，尽管两种广谱测试药物似乎通过不同的机制发挥作用，这表明它们可能是 WNV 以及其他相关黄病毒的潜在抗病毒候选药物。
