Apoptosis in Murine Norovirus-Infected RAW264.7 Cells Is Associated with Downregulation of Survivin
Apoptosis in Murine Norovirus-Infected RAW264.7 Cells Is Associated with Downregulation of Survivin
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DOI：
10.1128/jvi.02028-08
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发表时间：
2009-04-15
影响因子：
5.4
通讯作者：
Sosnovtsev, Stanislav V.
中科院分区：
文献类型：
--
作者：
Bok, Karin;Prikhodko, Victor G.;Sosnovtsev, Stanislav V.
诺如病毒(NV)被认为是人类非细菌性胃肠炎的主要原因。由于无法在任何细胞培养系统中繁殖，对人类NV的研究继续受到阻碍。直到最近，大多数关于新城疫病毒复制的数据都来自对猫杯状病毒和兔出血症病毒的研究，这两种病毒都是杯状病毒科的可培养成员。从这些研究中，有人提出杯状病毒诱导细胞凋亡，以促进病毒后代在宿主中的传播。MNV-1在RAW264.7细胞中生长的发现为研究细胞凋亡在NV感染中的作用提供了第一个细胞培养体系。我们首先证明了MNV-1复制触发了RAW264.7细胞的凋亡，然后证明了细胞死亡与caspase-9和caspase-3的激活通过线粒体途径有关。这一过程依赖于病毒复制，因为灭活的病毒未能诱导细胞凋亡的迹象。为了更好地了解MNV-1感染RAW264.7细胞诱导细胞凋亡的过程，我们研究了MNV-1感染细胞和模型感染细胞的表达谱。Survivin是凋亡抑制蛋白家族中的一员，其表达水平显著下调，与病毒基因组复制呈负相关。这项研究表明，与其他上调Survivin的病毒不同，MNV-1是第一个发现下调Survivin水平的病毒。我们观察到，MNV-1在RAW264.7细胞中的复制激活了caspase，导致了通过线粒体途径的凋亡，这可能是Survivin下调的结果。
Noroviruses (NVs) are recognized as a major cause of nonbacterial gastroenteritis in humans. Studies of the human NVs continue to be hampered by the inability to propagate them in any cell culture system. Until recently, most data concerning NV replication were derived from studies of feline calicivirus and rabbit hemorrhagic disease virus, which are cultivable members of the family Caliciviridae. From such studies, it was proposed that caliciviruses induce apoptosis to facilitate the dissemination of viral progeny in the host. The discovery that MNV type 1 (MNV-1) grows in RAW264.7 cells provided the first cell culture system for use in studying the role of apoptosis in NV infection. We first showed that MNV-1 replication triggered apoptosis in infected RAW264.7 cells and then demonstrated that cell death was associated with activation of caspase-9 and caspase-3 through the mitochondrial pathway. This process was dependent on virus replication, since inactivated virus failed to induce signs of apoptosis. In order to better understand the apoptotic process induced by MNV-1 infection of RAW264.7 cells, we investigated the expression profiles of MNV-1-infected versus mock-infected cells. Survivin, a member of the inhibitor of apoptosis protein family, was found to be significantly downregulated in an inverse relationship with the virus genome replication. This study showed that, unlike other viruses that upregulate survivin, MNV-1 is the first virus found to downregulate the levels of survivin. We observed that MNV-1 replication in RAW264.7 cells activated caspases, resulting in apoptosis through the mitochondrial pathway, possibly as a result of downregulation of survivin.