HIV突破血视网膜屏障引起眼部并发症的分子机制研究

Under highly active antiretroviral therapy (HAART) of HIV/AIDS patients, the HIV virus in blood can be kept in low level, researches show that HIV-1 virus could be detected in intraocular tissue such as aqueous humor of HIV/AIDS patients , even the virus in plasma is tested negative，and complications such as retinitis are induced. These results indicate that HIV-1 viruses breakthrough the blood-retinal barrier and possibly form HIV ocular reservoirs but the establishment mechanism is unclear. Our works have shown that the outer blood-retinal barrier layer, retinal pigment epithelial cell (RPE) can bind and uptake HIV-1. RPE cells express cell surface receptor DC-SIGN, which is HIV gp120 binding receptor. These data indicate that HIV-1 can penetrate blood retinal barrier and cause ocular complications. To explore the mechanism of HIV-1 virus breaking through the blood retinal barrier, we will observe the binding of DC-SIGN with HIV gp120 in vitro. We will package HIV-1 virus and observe the down-regulation of tight junctions proteins of RPE cells and RCEC cells. Then, we will explore the activation of cellular NFκB pathway-dependent MMPs induction. By collecting intraocular tissue samples, we will screen the target infectious cells and we explore the source of HIV-1 virus in intraocular tissue and its infection, replication and release. Then, we can investigate the possible mechanism of intraocular HIV-1 virus reservoir and HIV associated ocular complications. We aim to identify the mechanism of the disruption of the blood-barriers by HIV-1 virus, further, to clarify the mechanism of the establishment of HIV-1 ocular reservoir. Our studies will provide new methods for prevention and treatment of HIV-associated ocular complications.

高效抗逆转录病毒治疗可有效控制HIV/AIDS患者血液中病毒水平，而血液检测结果为阴性的患者眼内组织仍可检出病毒，HIV突破血-视网膜屏障可能形成眼部HIV储存库，但机制尚不明确。本项目组前期研究证明视网膜色素上皮细胞（RPE）表达HIV-1包膜糖蛋白gp120结合受体DC-SIGN，可结合病毒，提示HIV可能通过该途径突破屏障引起眼部并发症。为探讨可能的分子机制，本项目拟包装HIV-1病毒，体外观察HIV-1通过gp120结合DC-SIGN影响RPE、RCEC细胞间连接蛋白的表达，及此过程中NFκB信号通路与靶基因基质金属蛋白酶 MMPs间的相互作用；通过采集病人眼内组织标本，筛查眼内感染靶细胞，探讨病毒来源及其感染、复制、释放，形成眼部储存库与发生眼部并发症的可能机理，探究HIV破坏血-视网膜屏障建立眼部HIV储存库的分子机制，为诊治HIV相关眼部并发症提供思路。

在HAART治疗下，HIV患者眼内仍可以检测到高载量HIV病毒，甚至超过血液内载量，提示了眼内病毒感染难以清除。本课题组前期研究发现HIV突破血眼屏障进入眼内，并感染靶细胞形成可能的眼部储存库。吡格列酮，作为FDA批准用于治疗2型糖尿病的临床用药，可以减轻HIV炎症反应且减少HIV复制。基于以上推论，本课题组对血视网膜屏障视网膜色素上皮细胞的完整性及PPARγ保护血视网膜屏障的机制进行研究。发现PPARγ配体吡格列酮可以减轻HIV引起的RPE细胞炎症反应，通过NFKB通路减少MMPs的表达，从而保护HIV对血视网膜屏障的破坏作用。.视网膜是脑组织的延伸，视网膜小胶质细胞与脑小胶质统一来源，可能是眼内感染HIV的靶细胞。本课题组通过HIV患者眼内组织验证HIV患者眼内高载量HIV病毒，且视网膜组织内整合有gp120蛋白，通过进一步细胞实验，发现视网膜小胶质细胞表达HIV受体CD4，并且感染复制HIV病毒，成为眼内感染HIV的可能的靶细胞，为眼内形成HIV病毒储存库提供有力依据。