Centre for Pathophysiology Toulouse-Purpan (CPTP), INSERM, CNRS, University of Toulouse, Toulouse, France.
Hôpital Necker-Enfants Malades, Assistance Publique-Hôpitaux de Paris, Paris, France.
J Pathol. 2021 May;254(1):92-102. doi: 10.1002/path.5640. Epub 2021 Mar 24.
Congenital infection of the central nervous system by human cytomegalovirus (HCMV) is a leading cause of permanent sequelae, including mental retardation or neurodevelopmental abnormalities. The most severe complications include smooth brain or polymicrogyria, which are both indicative of abnormal migration of neural cells, although the underlying mechanisms remain to be determined. To gain better insight on the pathogenesis of such sequelae, we assessed the expression levels of a set of neurogenesis-related genes, using HCMV-infected human neural stem cells derived from embryonic stem cells (NSCs). Among the 84 genes tested, we found dramatically increased expression of the gene PAFAH1B1, encoding LIS1 (lissencephaly-1), in HCMV-infected versus uninfected NSCs. Consistent with these findings, western blotting and immunofluorescence analyses confirmed the increased levels of LIS1 in HCMV-infected NSCs at the protein level. We next assessed the migratory abilities of HCMV-infected NSCs and observed that infection strongly impaired the migration of NSCs, without detectable effect on their proliferation. Moreover, we observed increased immunostaining for LIS1 in brains of congenitally infected fetuses, but not in control samples, highlighting the clinical relevance of our findings. Of note, PAFAH1B1 mutations (resulting in either haploinsufficiency or gain of function) are primary causes of hereditary neurodevelopmental diseases. Notably, mutations resulting in PAFAH1B1 haploinsufficiency cause classic lissencephaly. Taken together, our findings suggest that PAFAH1B1 is a critical target of HCMV infection. They also shine a new light on the pathophysiological basis of the neurological outcomes of congenital HCMV infection, by suggesting that defective neural cell migration might contribute to the pathogenesis of the neurodevelopmental sequelae of infection. © 2021 The Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
人类巨细胞病毒 (HCMV) 引起的中枢神经系统先天感染是导致永久性后遗症的主要原因，包括智力迟钝或神经发育异常。最严重的并发症包括无脑回或多小脑回，这两者都表明神经细胞的异常迁移，尽管其潜在机制仍有待确定。为了更好地了解此类后遗症的发病机制，我们使用源自胚胎干细胞的 HCMV 感染的人神经干细胞评估了一组与神经发生相关的基因的表达水平。在测试的 84 个基因中，我们发现 HCMV 感染的神经干细胞中编码 LIS1（无脑回畸形 1）的基因 PAFAH1B1 的表达水平显著增加。这些发现与 Western blot 和免疫荧光分析一致，证实了 HCMV 感染的神经干细胞中 LIS1 蛋白水平增加。我们接下来评估了 HCMV 感染的神经干细胞的迁移能力，观察到感染强烈损害了神经干细胞的迁移，而对其增殖没有可检测的影响。此外，我们观察到先天性感染胎儿大脑中 LIS1 的免疫染色增加，但在对照样本中没有，这突出了我们发现的临床相关性。值得注意的是，PAFAH1B1 突变（导致杂合不足或功能获得）是遗传性神经发育疾病的主要原因。值得注意的是，导致 PAFAH1B1 杂合不足的突变导致经典无脑回畸形。总之，我们的研究结果表明 PAFAH1B1 是 HCMV 感染的关键靶标。它们还通过表明有缺陷的神经细胞迁移可能有助于感染后神经发育后遗症的发病机制，为先天性 HCMV 感染的神经后果的病理生理基础提供了新的认识。
