Molecular pathology in viral neurophathogenesis of developmental brain disorders

发育中的大脑极易受到巨细胞病毒感染，导致发育性脑障碍。在免疫功能低下的患者中，病毒的再激活也会诱发脑部疾病。为了证实潜伏性巨细胞病毒感染发生在大脑中的假说，我们将新生小鼠感染了小鼠巨细胞病毒（MCMV）并长期饲养，然后切除了大脑。在脑切片培养中观察到再激活。为了进一步分析，巢蛋白启动子gfp插入转基因（Tg）小鼠(Dr.H。Okano，庆应义塾大学)潜伏感染MCMV。在更昔洛韦（GCV）中培养未成熟的神经细胞，然后分离神经球。我们通过空斑实验证明了感染性病毒是从神经球中释放出来的。这一事实表明潜伏感染可能发生在神经干/祖细胞中。我们已经证明，神经元倾向于成为持续感染，并且在转基因小鼠中观察到早期基因e1启动子的神经元表达。我们研究了MCMV感染对NMDA受体表达的影响，NMDA受体是突触可塑性和神经元兴奋毒性所必需的。我们发现NMDA受体的表达在MCMV感染后降低，这可能与持续感染和引起功能障碍有关。此外，与神经干/祖细胞相比，我们发现胚胎干（ES）细胞对MCMV感染不敏感，但在胶质分化过程中获得了易感性。

Developing brains are highly susceptible to cytomegalovirus infection, causing developmental brain disorders. Brain disorders are also induced by reactivation of the virus in immune-compromised patients. In order to certify the hypothesis that latent CMV infection occurs in the brains, neonatal mice were infected with murine CMV (MCMV) and raised for a long time and removed the brains. Reactivation was observed in the brain slice cultures. For further analysis, nestin-promoter-GFP inserted transgenic (Tg) mice (provided Dr.H.Okano, Keio Univ.) were latently infected with MCMV. Immature neural cells cultures in the presence of ganciclovir (GCV), then, neurospheres were isolated. We demonstrated that infective virus is released from the neurospheres by plaque assay. This fact indicates that latent infection may occur in neural stem/progenitor cells. We have showed that neurons tend to become persistent infection and that neuronal expression of the early gene e1-promoter was observed in the transgenic mice. We investigated the effect of MCMV infection on the expression of NMDA rece ptors that are essential for the plasticity of synapses and neuronal excito-toxicity. We showed that expression of NMDA receptors were reduced by MCMV infection, probably relating to establish persistent infection and causing functional disorders. Furthermore, in contrast to neural stem/progenitor cells, we showed that embryonic stem (ES) cells are not susceptible to MCMV infection but acquired the susceptibility during the glial differentiation.