Human immunodeficiency virus type 1 Vpr induces apoptosis in human neuronal cells
Human immunodeficiency virus type 1 Vpr induces apoptosis in human neuronal cells
复制标题
DOI：
10.1128/jvi.74.20.9717-9726.2000
复制
发表时间：
2000-10-01
影响因子：
5.4
通讯作者：
Pomerantz, RJ
中科院分区：
文献类型：
--
作者：
Patel, CA;Mukhtar, M;Pomerantz, RJ
人类免疫缺陷病毒I型(HIV-1)感染中枢神经系统(CNS)会在某些感染者中导致艾滋病痴呆综合征(ADC)。最近的研究表明，ADC患者神经细胞凋亡的发生率增加，导致神经元脱落。值得注意的是，在患有神经系统疾病的艾滋病患者的脑脊液中检测到了较高水平的HIV-1辅助蛋白VPR。此外，细胞外VPR可形成离子通道，导致培养的大鼠海马神经元死亡。基于这些先前的发现，我们首先研究了HIV-1VPR蛋白在不同浓度范围内对人神经前体NT2细胞系的凋亡效应。这些研究表明，与HIV-1整合酶、麦芽糖结合蛋白(MBP)和MBP-VPR蛋白处理相比，VPR和包膜糖蛋白gp120以剂量依赖的方式诱导未分化的NT2细胞发生凋亡，对于成熟的分化神经元，VPR和gp120在1到100 ng/ml的浓度范围内也以剂量依赖的方式诱导细胞凋亡，末端脱氧核苷酸转移酶(TDT)介导的dUTP-生物素缺口末端标记和Annexin V细胞凋亡检测都证明了这一点。为了阐明vpr和gp120诱导NT2细胞系和分化的成熟神经细胞凋亡的细胞内途径和分子机制，我们在这些研究中检测了细胞裂解物中caspase-8的活性。VPR和gp120处理组在成熟神经元和未分化的NT2细胞中caspase-8的活性均显著增加，提示VPR可能通过激活caspase-8而在神经前体细胞系和成熟的人类神经元中发挥选择性的细胞毒作用，这些数据代表了VPR诱导的人神经细胞凋亡的特征，并提示细胞外VPR与其他慢病毒蛋白一起可能增加中枢神经系统的神经元凋亡，此外，鉴定VPR诱导的人神经细胞凋亡中caspase-8的细胞内激活可能为对抗HIV-1诱导的患有ADC的艾滋病患者的神经细胞凋亡提供治疗途径。
Human immunodeficiency virus type I (HIV-1) infection of the central nervous system (CNS) causes AIDS dementia complex (ADC) in certain infected individuals. Recent studies have suggested that patients with ADC have an increased incidence of neuronal apoptosis leading to neuronal dropout. Of note, a higher level of the HIV-1 accessory protein Vpr has been detected in the cerebrospinal fluid of AIDS patients with neurological disorders. Moreover, extracellular Vpr has been shown to form ion channels, leading to cell death of cultured rat hippocampal neurons. Based on these previous findings, we first investigated the apoptotic effects of the HIV-1 Vpr protein on the human neuronal precursor NT2 cell line at a range of concentrations. These studies demonstrated that apoptosis induced by both Vpr and the envelope glycoprotein, gp120, occurred in a dose-dependent manner compared to protein treatment with HIV-1 integrase, maltose binding protein (MBP), and MBP-Vpr in the undifferentiated NT2 cells, For mature, differentiated neurons, apoptosis was also induced in a dose-dependent manner by both Vpr and gp120 at concentrations ranging from 1 to 100 ng/ml, as demonstrated by both the terminal deoxynucleotidyltransferase (Tdt)-mediated dUTP-biotin nick end labeling and Annexin V assays for apoptotic cell death. In order to clarify the intracellular pathways and molecular mechanisms involved in Vpr- and gp120-induced apoptosis in the NT2 cell line and differentiated mature human neurons, we then examined the cellular lysates for caspase-8 activity in these studies. Vpr and gp120 treatments exhibited a potent increase in activation of caspase-8 in both mature neurons and undifferentiated NT2 cells, This suggests that Vpr may be exerting selective cytotoxicity in a neuronal precursor cell line and in mature human neurons through the activation of caspase-8, These data represent a characterization of Vpr-induced apoptosis in human neuronal cells, and suggest that extracellular Vpr, along with other lentiviral proteins, may increase neuronal apoptosis in the CNS, Also, identification of the intracellular activation of caspase-8 in Vpr-induced apoptosis of human neuronal cells may Lead to therapeutic approaches which can be used to combat HIV-1-induced neuronal apoptosis in AIDS patients with ADC.