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，影响美国约10万人，主要是非洲裔。b-珠蛋白基因E6 V单突变导致血红蛋白S（HbS）的产生和慢性溶血性贫血的发展。我们最近对一项全国出院调查的分析显示，SCD与HIV-1诊断频率较低（优势比0.33）相关，这表明SCD可能提供对HIV-1的保护。我们推测SCD患者的溶血性贫血通过激活血红素、铁和氧依赖性途径抑制HIV-1的转录。血红素诱导巨噬细胞铁调节基因的转录，包括血红素加氧酶-1（HO-1）、铁蛋白和铁输出蛋白，膜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，而调节膜铁转运蛋白内化和降解的铁调素的表达减少（以及我们的初步数据）。血红素诱导HO-1抑制体外巨噬细胞和T细胞中以及HIV-1感染的人源化小鼠中的HIV-1感染。我们以前已经表明，HIV-1转录抑制铁螯合剂或ferroportin。铁螯合剂抑制CDK 2和CDK 9的细胞活性，这两者对HIV-1转录至关重要。我们最近的研究结果表明，CDK 2直接磷酸化CDK 9的Ser 90，导致HIV-1转录的激活。因此，我们假设血血红素浓度增加、缺血和铁调素减少将升高HO-1和膜铁转运蛋白的水平和活性，减少细胞铁并上调HIF-1通路，导致Egr-1、p21的诱导和CDK 2和CDK 9的抑制。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。在具体目标1中，我们将分析SCD和SCD性状中的HIV-1抑制。在具体目标2中，我们将分析HIV-1抑制SCD和SCD性状的分子机制。在具体目标3中，我们将分析体内新型抑制剂HO-1，ferroportin和hepcidin途径。总的来说，我们提出的研究旨在阐明HIV-1抑制SCD和SCD性状的分子机制。我们的研究将揭示血红素、膜铁转运蛋白、铁调素和铁对HIV-1调控的新机制。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，如使用氯化血红素和铁螯合剂。

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.