Kosugi I, Shinmura Y, Kawasaki H, Arai Y, Li R Y, Baba S, Tsutsui Y
Second Department of Pathology, Hamamatsu University School of Medicine, Japan.
Lab Invest. 2000 Sep;80(9):1373-83. doi: 10.1038/labinvest.3780145.
Cytomegalovirus (CMV) is the most frequent infectious cause of developmental disorders of the central nervous system (CNS) in humans. Infection of the CNS stem cells seems to be primarily responsible for the generation of the brain abnormalities. In this study, we evaluated the infectivity of murine CMV (MCMV) in epidermal growth factor (EGF)-responsive CNS stem cells prepared from fetal mouse brains, and studied the effect of infection on growth and differentiation of the stem cells. The CNS stem cells were permissive for MCMV infection, although MCMV replication was slower than in mouse embryonic fibroblasts. MCMV infection inhibited the growth and DNA replication of the stem cells. A clonogenic assay revealed that MCMV infection suppressed generation of colonies from single stem cells. When uninfected stem cells were induced to differentiate, a decrease in expression of the primitive neuroepidermal marker nestin was observed by immunocytochemistry and flow cytometry, whereas expression of neurofilament and glial fibrillary acidic protein (GFAP) were induced. In virus-infected CNS stem cells, nestin expression was retained, whereas the expression of neurofilament was more severely inhibited than that of GFAP in these cells. Two-color flow cytometry showed that differentiated glial precursor cells were preferentially susceptible to MCMV infection. MCMV-infected and uninfected CNS stem cells were transplanted into the neonatal rat brains. The reduced number of infected stem cells were engulfed into the subventricular zone and expressed GFAP, but did not migrate further, in contrast to the uninfected stem cells. These results suggest that suppression of the growth of the CNS stem cells and inhibition of the neuronal differentiation by CMV infection may be primary causes of disorders of brain development in congenital CMV infection.
巨细胞病毒（CMV）是人类中枢神经系统（CNS）发育障碍最常见的感染性病因。CNS干细胞感染似乎是导致脑部异常的主要原因。在本研究中，我们评估了鼠巨细胞病毒（MCMV）对从胎鼠脑制备的表皮生长因子（EGF）反应性CNS干细胞的感染性，并研究了感染对干细胞生长和分化的影响。CNS干细胞对MCMV感染敏感，尽管MCMV复制比在小鼠胚胎成纤维细胞中慢。MCMV感染抑制了干细胞的生长和DNA复制。克隆形成试验表明，MCMV感染抑制了单个干细胞形成集落。当未感染的干细胞被诱导分化时，通过免疫细胞化学和流式细胞术观察到原始神经表皮标志物巢蛋白的表达减少，而神经丝蛋白和胶质纤维酸性蛋白（GFAP）的表达被诱导。在病毒感染的CNS干细胞中，巢蛋白表达得以保留，而在这些细胞中神经丝蛋白的表达比GFAP受到更严重的抑制。双色流式细胞术显示，分化的神经胶质前体细胞优先易受MCMV感染。将MCMV感染和未感染的CNS干细胞移植到新生大鼠脑中。与未感染的干细胞相比，感染的干细胞数量减少，被吞噬到脑室下区并表达GFAP，但没有进一步迁移。这些结果表明，CMV感染导致的CNS干细胞生长抑制和神经元分化抑制可能是先天性CMV感染中脑发育障碍的主要原因。
