Estrogen reverses progestin-mediated loss of genital mucosal barrier function

总结 艾滋病毒对妇女的影响超过任何其他威胁生命的传染病。它最常通过性传播， 其中病毒必须避开生殖器粘膜屏障以引起全身感染。临床研究表明艾滋病毒 更容易穿透这种防御的妇女使用注射性甲孕酮 乙酸盐（DMPA）。我们的研究小组为这种可能性提供了生物学上的可能性， 通过减少细胞间粘附分子的表达，促进小鼠对HSV-2感染的易感性 桥粒芯糖蛋白-1（DSG 1）和增加生殖器粘膜通透性。DMPA同样提高了 人源化小鼠生殖器HIV感染。确定这些结果的潜在机制，我们发现DMPA 对小鼠的治疗降低了阴道中肝配蛋白A3（EFNA 3）的水平;一种雌激素（E）受体靶基因显示， 促进上皮组织中DSG 1的表达。为我们的研究结果提供临床相关性，我们显示， 开始使用DMPA显示宫颈外DSG 1表达和粘膜渗透性变化与 在老鼠身上看到的。同样，与DMPA剂量相关的生殖器粘膜损伤也会增加， 恒河猴（RM）的渗透性。这些数据新揭示DMPA损害粘膜屏障保护。 然而，使用HIV感染的人源化小鼠模型，我们还发现， DMPA和阴道内（ivag）E通过增强生殖器粘膜完整性阻断病毒获得。这些结果 因此，确定了激素避孕策略的一个意想不到的优势，该策略联合收割机使用外源性 白蛋白和E（即，它们避免了由于单独使用抗氧化剂而导致的屏障保护的损失）。作为必要步骤 在建立这一方法，这一建议将阐明机制E介导的增强生殖 粘膜屏障功能，并确定E-释放ivag环（E-IVR）保护RM免受生殖器感染的能力 SIV传播。当然，我们将使用小鼠来确定E介导的EFNA 3通路的调节， DSG 1表达和增强生殖器粘膜屏障功能（Aim 1）。我们会制定一个RM大小的E-IVR， 递送与药物剂量相关的药物，并使用这些环比较EFNA 3和DSG 1表达 DMPA、DMPA和安慰剂IVR或DMPA和E-IVR治疗的RM中的粘膜屏障功能（目的2）。 最后，我们将比较给予DMPA、DMPA和安慰剂IVR的RM的生殖器SIV传播，或 DMPA和E-IVR随着病毒接种量的增加而出现重复性生殖器挑战（目标3）。这项工作 将确定E诱导EFNA 3信号通路促进生殖器上皮完整性的机制， 并证明E-IVRs通过消除DMPA介导的生殖器官功能减弱来阻断SIV传播， 粘膜屏障功能因此，这些研究将在高度相关的临床研究中提供重要的新信息。 模型，并证明在艾滋病毒感染高危人群中探索类似的避孕策略是合理的。

SUMMARY HIV affects more women than any other life-threatening infectious agent. It is most often sexually transmitted, where virus must evade the genital mucosal barrier to cause systemic infection. Clinical studies suggest HIV more easily penetrates this defense among women using the injectable progestin depot-medroxyprogesterone acetate (DMPA). Offering biological plausibility for this possibility, our research group showed that DMPA promoted mouse susceptibility to HSV-2 infection by reducing expression of the cell-cell adhesion molecule desmoglein-1 (DSG1) and increasing genital mucosal permeability. DMPA similarly boosted susceptibility of humanized mice to genital HIV infection. Identifying a potential mechanism for these results, we found DMPA treatment of mice lowered vaginal levels of ephrin A3 (EFNA3); an estrogen (E) receptor target gene shown to promote DSG1 expression in epithelial tissue. Providing clinical relevance for our findings, we showed women initiating DMPA use display changes in ectocervical DSG1 expression and mucosal permeability identical to those seen in mice. Likewise, pharmacologically relevant DMPA doses comparably enhanced genital mucosal permeability in rhesus macaques (RMs). These data newly reveal DMPA impairs mucosal barrier protection. However, using a humanized mouse model of HIV infection, we also uncovered that combined treatment with DMPA and intravaginal (ivag) E blocks virus acquisition by enhancing genital mucosal integrity. These results thus identified an unexpected advantage of hormonal contraceptive strategies that combine use of exogenous progestin and E (i.e., they avert loss of barrier protection caused by progestin use alone). As necessary steps in establishing this approach, this proposal will elucidate mechanisms of E-mediated enhancement of genital mucosal barrier function and define capacity of an E-releasing ivag ring (E-IVR) to protect RMs from genital SIV transmission. Expressly, we will use mice to define E-mediated regulation of EFNA3 pathways that induce DSG1 expression and boost genital mucosal barrier function (Aim 1). We will formulate a RM-sized E-IVR to deliver pharmacologically relevant drug doses, and use these rings to compare EFNA3 and DSG1 expression and mucosal barrier function in RM treated with DMPA, DMPA and placebo IVR, or DMPA and E-IVR (Aim 2). Finally, we will compare genital SIV transmission in RMs administered DMPA, DMPA and placebo IVR, or DMPA and E-IVR with repetitive genital challenges with escalating inoculums of the virus (Aim 3). This work will identify mechanisms by which E induces EFNA3 signaling pathways promoting genital epithelial integrity, and demonstrate that E-IVRs block SIV transmission by abrogating DMPA-mediated weakening of genital mucosal barrier function. These studies will thus deliver important new information in a highly relevant clinical model, and justify exploration of similar contraceptive strategies in populations at high risk for HIV acquisition.