抗dsDNA抗体交叉反应NMDAR调控CREB-BDNF及PI3K/Akt信号通路在HIV相关神经认知紊乱发病中的作用机制研究

HIV-associated neurocognitive disorder (HAND) has a high incidence in AIDS patients. The pathogenesis remains to be revealed, and there is a lack of early diagnostic biomarker, which seriously threatens the life of patients. According to the literature, anti-dsDNA antibody cross-reacting with NMDAR can induce neuronal excitotoxicity. Previously, our team found that 57% of the antibodies cloned from HIV-infected individuals were anti-dsDNA antibodies, while there were no such antibodies in healthy people. The anti-dsDNA antibodies could recognize NMDAR, enhance Ca2+ influx, inhibit the activation of CREB and Akt, and finally induce SH-SY5Y cell apoptosis. According to the literature update and our preliminary data, we hypothesize that the anti-dsDNA antibodies of HIV-infected individuals can regulate the downstream CREB-BDNF and PI3K/Akt signaling pathways by cross-reacting with NMDAR, and mediate the occurrence of HAND. We plan to analyze the correlation between the serum NMDAR cross-reactive anti-dsDNA antibody levels and the disease progression in patients with HAND. Then, we will measure the expression and activation levels of molecules and proteins involved in CREB-BDNF and PI3K/Akt signaling pathways and evaluate the cell survival rate in vitro, and symptoms of neuronal cognitive impairment in vivo. This study is aimed to reveal the molecular mechanism of anti-dsDNA cross-reactive with NMDAR in the pathogenesis of HAND, and provide theoretical basis for the finding of new biomarkers to achieve early diagnosis of HAND.

HIV相关神经认知紊乱（HAND）在AIDS患者中发病率高，发病机制尚不明确，缺乏早期诊断标志，严重威胁患者生命安全。文献报道：抗dsDNA抗体交叉反应NMDAR可介导的神经兴奋性毒性。课题组前期发现：HIV感染者抗体库有57%是抗dsDNA抗体，而健康人无此类抗体；该种抗体可识别NMDAR，增强Ca2+内流，抑制CREB和Akt活化，使神经细胞凋亡。我们推测：HIV感染者的抗dsDNA抗体可通过交叉反应NMDAR，调控下游CREB-BDNF和PI3K/Akt信号通路，介导HAND发生。本研究拟分析HAND患者血清NMDAR交叉反应性抗dsDNA抗体水平与疾病进程的相关性，并观察细胞和动物实验中CREB-BDNF及PI3K/Akt通路相关分子表达、细胞生存率和小鼠症状，揭示抗dsDNA抗体交叉反应NMDAR参与HAND发生的机制，为HAND早期诊断寻找新的生物标志物提供理论依据。

HIV相关神经认知紊乱（HAND）在AIDS患者中发病率高，发病机制尚不明确，缺乏早期诊断标志，严重威胁患者生命安全。文献报道：抗dsDNA抗体交叉反应NMDAR可介导的神经兴奋性毒性。我们通过单细胞PCR的方法扩增了接受抗逆转录病毒治疗(ART)的慢性HIV感染者(HIVD)和健康供者(HD)的外周血单个母细胞免疫球蛋白重链和轻链可变区，为进一步的免疫组库分析奠定基础。我们比较了多个慢性HIVDs在ART治疗后、停止治疗和HD中的浆母细胞免疫组库表达谱，阐明了慢性HIV感染期间浆母细胞免疫组库的特征。同时，我们通过慢性HIV感染者浆母细胞克隆的抗体对自身抗原的鉴定识别，发现NMDAR上有与双链DNA（dsDNA）有相似的多肽序列DWEYS，这些抗体因此能够识别NMDAR，通过细胞实验证明抗体可通过相同表位与神经细胞结合，介导NDMAR内吞并引起钙离子内流信号改变，对神经细胞的活性造成影响；通过免疫荧光染色发现小鼠神经组织切片上这些抗体同样能够结合。这些结果初步揭示慢性HIV感染者可产生自身反应性抗体，并有潜在的致病性，可能通过NMDAR的结合攻击如神经细胞等，为HIV相关神经认知功能紊乱这一在慢性HIV感染者中发生率高的并发症提供一个新的致病机制。