Kleinschmidt Malte C, Michaelis Martin, Ogbomo Henry, Doerr Hans-Wilhelm, Cinatl Jindrich
Institute for Medical Virology, Johann Wolfgang Goethe-University, Frankfurt am Main, Germany.
BMC Microbiol. 2007 May 29;7:49. doi: 10.1186/1471-2180-7-49.
West Nile virus (WNV) infection can cause severe meningitis and encephalitis in humans. Apoptosis was recently shown to contribute to the pathogenesis of WNV encephalitis. Here, we used WNV-infected glioma cells to study WNV-replication and WNV-induced apoptosis in human brain-derived cells.
T98G cells are highly permissive for lytic WNV-infection as demonstrated by the production of infectious virus titre and the development of a characteristic cytopathic effect. WNV replication decreased cell viability and induced apoptosis as indicated by the activation of the effector caspase-3, the initiator caspases-8 and -9, poly(ADP-ribose)polymerase (PARP) cleavage and the release of cytochrome c from the mitochondria. Truncation of BID indicated cross-talk between the extrinsic and intrinsic apoptotic pathways. Inhibition of the caspases-8 or -9 inhibited PARP cleavage, demonstrating that both caspases are involved in WNV-induced apoptosis. Pan-caspase inhibition prevented WNV-induced apoptosis without affecting virus replication.
We found that WNV infection induces cell death in the brain-derived tumour cell line T98G by apoptosis under involvement of constituents of the extrinsic as well as the intrinsic apoptotic pathways. Our results illuminate the molecular mechanism of WNV-induced neural cell death.
西尼罗河病毒（WNV）感染可导致人类严重的脑膜炎和脑炎。最近研究表明，细胞凋亡在WNV脑炎的发病机制中起作用。在此，我们使用WNV感染的胶质瘤细胞来研究WNV在人脑源细胞中的复制及WNV诱导的细胞凋亡。
T98G细胞对WNV的裂解性感染高度敏感，这可通过感染性病毒滴度的产生及特征性细胞病变效应的出现得以证明。WNV复制降低了细胞活力并诱导细胞凋亡，这可通过效应半胱天冬酶-3、起始半胱天冬酶-8和-9的激活、聚（ADP-核糖）聚合酶（PARP）的裂解以及细胞色素c从线粒体的释放得以表明。BID的截断表明外源性和内源性凋亡途径之间存在相互作用。对半胱天冬酶-8或-9的抑制可抑制PARP裂解，表明这两种半胱天冬酶均参与WNV诱导的细胞凋亡。泛半胱天冬酶抑制可预防WNV诱导的细胞凋亡，而不影响病毒复制。
我们发现WNV感染通过外源性和内源性凋亡途径的成分参与，在脑源肿瘤细胞系T98G中诱导细胞凋亡。我们的结果阐明了WNV诱导神经细胞死亡的分子机制。
