HIV Microbicides and the Vaginal Microbiome

描述(由申请人提供)：经阴道的艾滋病毒杀菌剂提供了减少艾滋病毒传播的巨大希望，但第三阶段杀微生物剂试验失败了。在一些研究中，使用杀菌剂的患者比使用安慰剂的患者有更高的艾滋病毒传播率。这些失败还没有明确的解释，但有一种假设认为，杀菌剂改变阴道微生物区系的方式增加了炎症或激活了潜在的艾滋病毒宿主细胞，从而加强了传播。研究了杀菌剂对阴道菌群的影响，发现对微生物群几乎没有显著影响，但他们使用了传统的培养技术。最近使用与培养无关的分子技术的研究表明，包括阴道在内的许多人类微生物环境中的菌群比之前所了解的要复杂得多，传统的培养技术只检测到环境中的一小部分微生物。我们建议使用这些新的独立于培养的技术来探索这样一个假设，即杀菌剂改变阴道微生物群的方式可以通过这些特定的目的潜在地增强艾滋病毒的传播：1)在使用Affymetrix PhyloChip芯片进行的关于壬氧基-9(N-9)、硫酸纤维素(CS)和安慰剂的Conrad重复第一阶段研究中，检查使用杀菌剂之前和之后的阴道微生物菌群2)在第一阶段研究中使用微生物DNA测序来检查使用杀菌剂前后阴道微生物组中的表达基因组合，3)在使用PhyloChip和直接16S rRNA基因测序失败的Conrad CS 3期研究中，检查使用杀菌剂前后的微生物种类组成。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，根据PhyloChip的评估，杀微生物剂的使用导致阴道菌群的显著变化。确定杀微生物剂的应用是否与可能促进艾滋病毒传播的阴道微生物群变化有关，将有助于理解先前第三阶段试验的失败，并将有助于今后的杀微生物剂开发工作，因为如果阴道菌群的有害变化与杀菌剂的使用有关，未来的杀微生物剂开发工作将需要谨慎的措施，以避免在阴道微生物群中引起潜在的有害变化。用于预防艾滋病毒性传播的阴道杀微生物剂在减少艾滋病毒性传播和遏制艾滋病毒大流行方面提供了巨大的理论希望，特别是在艾滋病毒流行率最高的地区。不幸的是，几个大型的艾滋病毒杀微生物剂后期试验都失败了，原因不明，使用杀微生物剂的研究对象的艾滋病毒传播率高于使用安慰剂的研究对象。我们假设，导致杀微生物剂失败的一个因素是，它们的使用会使阴道内的微生物菌群产生有害的变化，从而导致艾滋病毒复制细胞的炎症或激活，从而增加艾滋病毒传播的风险。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地对几乎所有生活在阴道中的微生物进行分类，并确定艾滋病毒杀菌剂的使用如何改变微生物的数量。确定艾滋病毒杀微生物剂的使用导致阴道菌群发生重大的、潜在的有害变化，将有助于解释现有杀微生物剂未能防止艾滋病毒传播的原因，并可能有助于开发新的、更有效的艾滋病毒杀菌剂。

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.