Inhibition of HIV-1 in Sickle Cell Disease

描述（由申请人提供）：镰状细胞病（SCD）是一种遗传性疾病，在美国影响约100,000人，主要是非洲人后裔。b-球蛋白基因E6V单突变可导致血红蛋白S （HbS）的产生和慢性溶血性贫血的发生。我们最近对一项全国医院出院调查的分析显示，SCD与HIV-1诊断频率较低相关（优势比0.33），这表明SCD可能对HIV-1有保护作用。我们假设SCD中的溶血性贫血通过激活血红素、铁和氧依赖途径导致HIV-1转录的抑制。血红素诱导巨噬细胞中铁调控基因的转录，包括血红素氧合酶-1 （HO-1）、铁蛋白和铁输出蛋白，铁转运蛋白导致铁输出增加和细胞铁减少。在SCD中，HO-1的表达增加，而调节铁转运蛋白内化和降解的hepcidin的表达减少（这也是我们的初步数据）。血红素诱导HO-1抑制体外巨噬细胞和t细胞以及HIV-1感染人源化小鼠的HIV-1感染我们之前已经证明HIV-1转录被铁螯合剂或铁转运蛋白抑制。铁螯合剂抑制CDK2和CDK9的细胞活性，两者都是HIV-1转录的关键。我们最近的研究结果表明，CDK2直接磷酸化CDK9的Ser90，导致HIV-1转录的激活。因此，我们假设血血红素浓度升高、缺血和hepcidin降低会升高HO-1和铁转运蛋白的水平和活性，减少细胞铁，上调HIF-1通路，从而诱导Egr-1、p21和抑制CDK2和CDK9。该蛋白网络的上调将导致SCD条件下HIV-1转录和病毒复制的抑制。在Specific Aim 1中，我们将分析HIV-1在SCD和SCD性状中的抑制作用。在Specific Aim 2中，我们将分析HIV-1抑制SCD的分子机制和SCD性状。在Specific Aim 3中，我们将分析新的抑制剂HO-1、铁转运蛋白和hepcidin在体内的途径。总的来说，我们提出的研究旨在阐明SCD和SCD性状设置中HIV-1抑制的分子机制。我们的研究将揭示血红素、铁转运蛋白、hepcidin和铁调控HIV-1的新机制。我们提出的研究是重要的，因为它们可能导致新的治疗方法，如使用血红素和铁螯合剂。

DESCRIPTION (provided by applicant): Sickle-cell disease (SCD) is a hereditary disorder that affects approximately 100,000 people in the USA, primarily of African descent. Single E6V mutation in b-globin gene leads to the production of hemoglobin S (HbS) and development of chronic hemolytic anemia. Our recent analysis of a national hospital discharge survey showed an association of SCD with lower frequency of HIV-1 diagnosis (odds ratio 0.33) suggesting that SCD might offer a protection from HIV-1. We hypothesize that hemolytic anemia in SCD leads to inhibition of HIV-1 transcription through the activation of heme-, iron and oxygen-dependent pathways. Heme induces transcription of iron regulatory genes in macrophages, including heme oxygenase-1 (HO-1), ferritin and iron export protein, ferroportin leading to the increased iron export and reduction of cellular iron. In SCD, expression of HO-1 is increased whereas expression of hepcidin that regulates internalization and degradation of ferroportin is decreased (and also our preliminary data). Induction of HO-1 by heme inhibits HIV-1 infection in macrophages and T-cells in vitro and in HIV-1 infected humanized mice. We have previously shown that HIV-1 transcription is inhibited by iron chelators or ferroportin. Iron chelators inhibi cellular activities of CDK2 and CDK9, both critical for HIV-1 transcription. Our recent findings demonstrate that CDK2 directly phosphorylates CDK9's Ser90 resulting in the activation of HIV-1 transcription. We, therefore, hypothesize that increased blood heme concentration, ischemia and decreased hepcidin will elevate levels and activity of HO-1 and ferroportin, reduce cellular iron and upregulate HIF-1 pathway leading to the induction of Egr-1, p21 and inhibition of CDK2 and CDK9. Upregulation of this protein network will lead to the inhibition HIV-1 transcription and viral replication in SCD condition. In Specific Aim 1, we will analyze HIV-1 inhibition in SCD and SCD trait. In Specific Aim 2, we will analyze molecular mechanisms of HIV-1 inhibition in SCD and SCD trait. In Specific Aim 3, we will analyze novel inhibitors HO-1, ferroportin and hepcidin pathways in vivo. Collectively, our proposed research is designed to elucidate the molecular mechanisms of HIV-1 inhibition in the settings of SCD and SCD trait. Our studies will uncover novel mechanisms of HIV-1 regulation by heme, ferroportin, hepcidin, and iron. Our proposed studies are significant because they may lead to novel therapeutics, such as the use of hemin and iron chelators.