Pathogenesis of a JC Virus Variant in Pyramidal Neurons

描述（由申请人提供）：我们描述了一种在免疫抑制个体中由JC病毒（JCV）感染皮质锥体神经元引起的新的临床实体。该患者在MRI上表现为局限于半球灰质的病变，出现失语、进行性认知功能障碍和癫痫发作，并迅速死亡。我们称这种疾病为JCV脑病（JCVE），因为它不同于由JCV感染神经胶质细胞引起的进行性多灶性白质脑病（PML）。死后组织学评价首次证实了JCV对皮质锥体神经元的产生性和溶解性感染。我们分析了从该患者大脑中获得的JCV分子克隆JCVCPN1的全长序列，发现了一个原型样调控区（RR）和Agnoprotein基因中一个新的143 bp的缺失。随后在另外三名PML患者的神经元或脑脊液中发现了CPN突变体。我们假设JCV序列的改变是导致该患者皮质锥体神经元特异性感染的原因。然而，JCVCPN1在神经元中的生长是通过其RR、新的Agnoprotein缺失，还是两者兼而有之，目前尚不清楚。此外，我们假设皮质神经元的JCV感染也可能发生在其他个体中，包括位于灰质交界处或灰质内脱髓鞘病变的PML患者。最后，我们假设位于海马区的其他锥体神经元也可能被JCV变异感染，这可能导致癫痫发作的发生。为了验证这些假设，我们将追求以下一系列具体目标：目的1)确定体外JCVCPN1的宿主细胞范围；目的2)确定Agnoprotein缺失和原型样RR对体外JCVCPN1表型的贡献；目的3)利用免疫组织化学和激光捕获显微解剖技术表征PML患者档案样本中皮质锥体神经元JCV感染的流行程度，并鉴定CPN1突变；目的4)研究免疫抑制个体和小鼠海马锥体神经元JCV感染海马硬化或顽固性癫痫患者

DESCRIPTION (provided by applicant): We have described a novel clinical entity caused by JC virus (JCV) infection of cortical pyramidal neurons in an immunosuppressed individual. This patient presented with lesions restricted to the hemispheric gray matter on MRI, developed aphasia, progressive cognitive dysfunction and seizures and had a rapid fatal outcome. We called this disease JCV encephalopathy (JCVE), since it is distinct from Progressive Multifocal Leukoencephalopathy (PML), caused by JCV infection of glial cells. Post mortem histological evaluation demonstrated for the first time a productive and lytic infection of cortical pyramidal neurons by JCV. We have analyzed the full length sequence of a molecular clone of JCV obtained from the brain of this patient, JCVCPN1, which revealed an archetype-like regulatory region (RR), and a novel 143 bp deletion in the Agnoprotein gene. The CPN mutant was subsequently found in the neurons or cerebrospinal fluid of three other patients with PML. We hypothesize that changes in JCV sequence are responsible for the specific infection of cortical pyramidal neurons in this patient. However, whether JCVCPN1 growth in neurons is made possible by its RR, the novel Agnoprotein deletion, or both, remains unclear. Furthermore, we postulate that JCV infection of cortical neurons may also occur in other individuals, including in PML patients with demyelinating lesions located at the gray white- junction or within the gray matter. Finally, we hypothesize that other pyramidal neurons, located in the hippocampus may also be infected by JCV variants, which could lead to the development of seizures. To test these hypotheses, we will pursue the following set of Specific Aims: Aim 1) Characterize the host cell range of JCVCPN1 in vitro Aim 2) Determine the contributions of the Agnoprotein deletion and archetype-like RR to the phenotype of JCVCPN1 in vitro Aim 3) Characterize the prevalence of JCV infection of cortical pyramidal neurons in archival samples from PML patients and identify the CPN1 mutation using immunohistochemistry and laser capture microdissection Aim 4) Investigate JCV infection of hippocampal pyramidal neurons in immunosuppressed individuals and in patients with hippocampal sclerosis or intractable epilepsy