MicroRNA miR-21 Attenuates Human Cytomegalovirus Replication in Neural Cells by Targeting Cdc25a
MicroRNA miR-21 Attenuates Human Cytomegalovirus Replication in Neural Cells by Targeting Cdc25a
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MicroRNA miR-21 通过靶向 Cdc25a 减弱神经细胞中的人巨细胞病毒复制
DOI：
10.1128/jvi.01740-14
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发表时间：
2015-01-01
影响因子：
5.4
通讯作者：
Luo, Min-Hua
中科院分区：
文献类型：
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作者：
Fu, Ya-Ru;Liu, Xi-Juan;Luo, Min-Hua
摘要先天性人巨细胞病毒（HCMV）感染是导致出生缺陷的主要原因，主要表现为神经系统疾病。HCMV感染改变了细胞microRNA（miR）的表达，并诱导细胞周期停滞，这反过来又改变了细胞环境，有利于病毒复制。先前的观察发现，HCMV感染降低了神经祖细胞/干细胞（NPC）中的miR-21表达。在这里，我们发现NPC和U-251 MG细胞的感染抑制miR-21，同时增加Cdc 25 a的水平，Cdc 25 a是一种细胞周期调节因子，也是miR-21的已知靶点。这些对感染的相反反应促使研究miR-21，Cdc 25 a和病毒复制之间的关系。miR-21在NPC和U-251 MG细胞中的过表达抑制了病毒基因表达、基因组复制和感染性子代的产生，而在U-251 MG细胞中的miR-21的shRNA敲低增加了病毒基因表达。相反，Cdc 25 a在U-251 MG细胞中的过表达增加了病毒基因表达和感染性子代的产生，并克服了miR-21过表达的抑制作用。三种病毒基因产物-IE 1，pp 71和UL 26-显示在转录水平上抑制miR-21表达。这些结果表明，Cdc 25 a促进HCMV复制和HCMV感染后Cdc 25 a水平的升高部分是由于HCMV介导的miR-21的抑制。因此，miR-21是受HCMV感染调节的内在抗病毒因子。这表明miR-21下调在发育中的CNS的HCMV感染的神经发病机制中的作用。人类巨细胞病毒（human cytomegalovirus，HCMV）是一种普遍存在的病原体，在我国人群中具有很高的患病率，先天性HCMV感染是导致出生缺陷的主要原因。阐明病毒-宿主相互作用控制HCMV在神经元细胞中的复制对于理解先天性感染导致的出生缺陷的神经发病机制至关重要。在这项研究中，我们证实HCMV感染下调miR-21，但上调Cdc 25 a。进一步确定细胞miRNA miR-21对神经祖细胞/干细胞和U-251 MG胶质母细胞瘤/星形细胞瘤细胞中HCMV复制的负面影响。更重要的是，我们的研究结果提供了第一个证据，证明miR-21通过靶向Cdc 25 a（一种重要的细胞周期调节因子）负调控HCMV复制。我们进一步发现IE 1、pp 71和UL 26的病毒基因产物在抑制miR-21表达中起作用，这反过来又导致Cdc 25 a增加并有利于HCMV复制。因此，miR-21似乎是一种内在的抗病毒因子，代表了治疗干预的潜在靶点。
ABSTRACT Congenital human cytomegalovirus (HCMV) infection is a leading cause of birth defects, primarily manifesting as neurological disorders. HCMV infection alters expression of cellular microRNAs (miRs) and induces cell cycle arrest, which in turn modifies the cellular environment to favor virus replication. Previous observations found that HCMV infection reduces miR-21 expression in neural progenitor/stem cells (NPCs). Here, we show that infection of NPCs and U-251MG cells represses miR-21 while increasing the levels of Cdc25a, a cell cycle regulator and known target of miR-21. These opposing responses to infection prompted an investigation of the relationship between miR-21, Cdc25a, and viral replication. Overexpression of miR-21 in NPCs and U-251MG cells inhibited viral gene expression, genome replication, and production of infectious progeny, while shRNA-knockdown of miR-21 in U-251MG cells increased viral gene expression. In contrast, overexpression of Cdc25a in U-251MG cells increased viral gene expression and production of infectious progeny and overcame the inhibitory effects of miR-21 overexpression. Three viral gene products—IE1, pp71, and UL26—were shown to inhibit miR-21 expression at the transcriptional level. These results suggest that Cdc25a promotes HCMV replication and elevation of Cdc25a levels after HCMV infection are due in part to HCMV-mediated repression of miR-21. Thus, miR-21 is an intrinsic antiviral factor that is modulated by HCMV infection. This suggests a role for miR-21 downregulation in the neuropathogenesis of HCMV infection of the developing CNS. IMPORTANCE Human cytomegalovirus (HCMV) is a ubiquitous pathogen and has very high prevalence among population, especially in China, and congenital HCMV infection is a major cause for birth defects. Elucidating virus-host interactions that govern HCMV replication in neuronal cells is critical to understanding the neuropathogenesis of birth defects resulting from congenital infection. In this study, we confirm that HCMV infection downregulates miR-21 but upregulates Cdc25a. Further determined the negative effects of cellular miRNA miR-21 on HCMV replication in neural progenitor/stem cells and U-251MG glioblastoma/astrocytoma cells. More importantly, our results provide the first evidence that miR-21 negatively regulates HCMV replication by targeting Cdc25a, a vital cell cycle regulator. We further found that viral gene products of IE1, pp71, and UL26 play roles in inhibiting miR-21 expression, which in turn causes increases in Cdc25a and benefits HCMV replication. Thus, miR-21 appears to be an intrinsic antiviral factor that represents a potential target for therapeutic intervention.