HIV Microbicides and the Vaginal Microbiome

描述（由申请人提供）：阴道HIV杀微生物剂为减少HIV传播提供了很大的希望，但3期杀微生物剂试验失败了。在一些研究中，使用杀微生物剂的患者比使用安慰剂的受试者有更高的艾滋病毒传播率。对于这些失败没有明确的解释，但有一种假设认为，杀微生物剂改变了阴道微生物植物群，增加了炎症或激活了潜在的HIV宿主细胞，增强了传播。研究了杀微生物剂对阴道植物群的影响，发现对微生物组几乎没有显著影响，但他们使用了传统的培养技术。最近使用分子、非培养技术的研究表明，包括阴道在内的许多人类微生物环境中的植物群比以前认识到的要复杂得多，并且传统的培养技术只能检测到环境中的一小部分微生物。我们建议使用这些新的不依赖培养的技术来探索杀微生物剂改变阴道微生物组的假设，这些方式可能通过这些特定的目的增强艾滋病毒的传播：1）在CONRAD重复的壬苯醇醚-9（N-9）、硫酸纤维素（CS）的1期研究中，在杀微生物剂应用之前和之后检查阴道微生物植物群，2）在1期研究中使用微生物cDNA测序检查在杀微生物剂应用之前和之后阴道微生物组中表达基因的组合，和3）在使用PhyloChip和直接16 S rRNA基因测序失败的CONRAD CS 3期研究中，检查在应用杀微生物剂之前和之后的微生物物种组成。我们建议从项目的初始R21阶段过渡到R33阶段的主要里程碑是证明杀微生物剂的使用导致阴道植物群的显著改变，正如PhyloChip所评估的那样。确定杀微生物剂的应用是否与阴道微生物组的变化有关，这可能会增加艾滋病毒的传播，这将有助于理解以前3期试验的失败，并有助于未来的杀微生物剂开发工作，因为如果阴道植物群的有害变化与杀微生物剂的使用有关，未来的杀微生物剂开发工作将需要采取谨慎的措施，以避免诱导阴道微生物组的潜在有害变化。预防艾滋病毒性传播的阴道杀微生物剂在理论上为减少艾滋病毒性传播和遏制艾滋病毒流行提供了巨大的希望，特别是在艾滋病毒流行率最高的地区。不幸的是，几个大型的HIV杀微生物剂后期试验由于未知原因失败了，使用杀微生物剂的研究对象的HIV传播率高于使用安慰剂的对象。我们假设，导致杀微生物剂失效的一个因素是，它们的使用对生活在阴道中的微生物植物群产生了有害的变化，这导致炎症或HIV复制细胞的激活，增加了HIV传播的风险。在我们的研究中，我们建议使用新的分子生物学技术来全面分类阴道中的所有微生物，并确定HIV杀微生物剂的使用如何改变微生物的种群。确定HIV杀微生物剂的使用导致阴道植物群的显著的、潜在有害的改变将有助于解释现有杀微生物剂未能预防HIV传播的原因，并可能有助于开发新的、更有效的HIV杀微生物剂。

DESCRIPTION (provided by applicant): Vaginal HIV microbicides offer great promise to reduce HIV transmission, but phase 3 microbicide trials have failed. In some studies, patients using the microbicides had higher HIV transmission rates than did subjects using placebos. There is no clear explanation for these failures, but one hypothesis holds that microbicides alter the vaginal microbial flora in ways that increase inflammation or activate potential HIV host cells, enhancing transmission. Studies examining the effects of microbicides on the vaginal flora found few significant effects on the microbiome, but they used conventional culture techniques. Recent studies using molecular, culture-independent techniques showed that the flora in many human microbial environments, including the vagina, is much more complex than previously appreciated and that conventional culture techniques only detect a small fraction of the microbes in the environment. We propose to use these new culture-independent techniques to explore the hypothesis that microbicides alter the vaginal microbiome in ways that can potentially enhance HIV transmission via these specific aims: 1) Examine the vaginal microbial flora before and after microbicide application in a CONRAD repeat phase 1 study of nonoxynol-9 (N-9), cellulose sulfate (CS), and placebo using Affymetrix PhyloChip microarrays 2) Examine the portfolio of expressed genes in the vaginal microbiome before and after microbicide application using microbial cDNA sequencing in the phase 1 study, and 3) Examine the microbial species composition before and after microbicide application in the CONRAD CS phase 3 study that failed using the PhyloChip and direct 16S rRNA gene sequencing. The main milestone we propose to transition from the initial R21 phase of the project to the R33 phase is the demonstration that microbicide use leads to a significant alteration in the vaginal flora as assessed by the PhyloChip. Determining whether microbicide application is associated with vaginal microbiome changes that could enhance HIV transmission would aid understanding of the failure of the previous phase 3 trials and would help future microbicide development efforts because, if harmful changes in vaginal flora are associated with microbicide use, future microbicide development efforts would require careful measures to avoid inducing potentially harmful changes in the vaginal microbiome. Vaginal microbicides for the prevention of HIV sexual transmission offer great theoretical promise to reduce HIV sexual transmission and blunt the HIV pandemic, particularly in regions with the highest HIV prevalence rates. Unfortunately, several large late phase trials of HIV microbicides have failed for unknown reasons, with the research subjects using the microbicides having rates of HIV transmission higher than subjects using placebos. We hypothesize that one factor contributing to the failure of the microbicides is that their use produces a harmful change in the microbial flora living in the vagina, which leads to inflammation or activation of the cells that HIV replicates in, increasing the risks of HIV transmission. In our study, we propose to use new molecular biological techniques to comprehensively catalog essentially all of the microbes living in the vagina and determine how the use of HIV microbicides alters the population of the microbes. Determining that the use of HIV microbicides lead to a significant, potentially harmful alteration in the population of vaginal flora would help explain the failure of the existing microbicides to prevent HIV transmission and may help enable the development of new, more effect HIV microbicides.