HIV Microbicides and the Vaginal Microbiome

描述（由申请人提供）：阴道杀菌剂为减少艾滋病毒传播提供了巨大的希望，但三期杀菌剂试验失败了。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。对于这些失败还没有明确的解释，但有一种假设认为，杀菌剂会以增加炎症或激活潜在的HIV宿主细胞的方式改变阴道微生物菌群，从而增强传播。研究杀微生物剂对阴道菌群的影响，发现对微生物群的影响不大，但他们使用的是传统的培养技术。最近使用分子培养独立技术的研究表明，包括阴道在内的许多人类微生物环境中的菌群比以前认识到的要复杂得多，而传统的培养技术只能检测到环境中微生物的一小部分。我们建议使用这些新的与培养无关的技术来探索杀微生物剂改变阴道微生物组的假设，这些方法可能会通过以下特定目的增强艾滋病毒的传播：1)在CONRAD重复一期研究中，使用Affymetrix PhyloChip芯片检测应用杀菌剂前后阴道微生物菌群，分别为壬氧醇-9 （N-9）、硫酸纤维素（CS）和安慰剂。2)在一期研究中，使用微生物cDNA测序检测应用杀菌剂前后阴道微生物菌群表达基因组合。3)使用PhyloChip和直接16S rRNA基因测序，检测在CONRAD CS 3期研究中使用杀菌剂失败前后的微生物种类组成。我们建议将项目从最初的R21阶段过渡到R33阶段的主要里程碑是证明杀菌剂的使用会导致经PhyloChip评估的阴道菌群发生重大变化。确定杀微生物剂的应用是否与阴道微生物组的变化有关，而阴道微生物组的变化可能会增强艾滋病毒的传播，这将有助于了解之前3期试验的失败，并有助于未来的杀微生物剂开发工作，因为如果阴道菌群的有害变化与杀微生物剂的使用有关，那么未来的杀微生物剂开发工作将需要谨慎的措施，以避免引起阴道微生物组的潜在有害变化。用于预防艾滋病毒性传播的阴道杀微生物剂在理论上有望减少艾滋病毒性传播和遏制艾滋病毒大流行，特别是在艾滋病毒流行率最高的区域。不幸的是，一些大型的艾滋病毒杀微生物剂后期试验由于未知的原因失败了，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，导致杀微生物剂失效的一个因素是，它们的使用会对生活在阴道内的微生物菌群产生有害的变化，从而导致炎症或激活HIV复制的细胞，增加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对生活在阴道中的所有微生物进行全面分类，并确定使用HIV杀菌剂如何改变微生物的数量。确定使用艾滋病毒杀菌剂会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菌剂无法预防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.