Pathogen trapping by genital mucus secretions

描述(申请人提供)：女性生殖道的粘液分泌物即使是病毒大小的物体也极难穿透。那么，为什么这些屏障有时无法防止性传播的病原体？我们的试验数据表明，一些病原体太大，无法穿透粘液网孔间距(孔隙大小)，而且粘液还会在一些病原体到达目标细胞之前捕获它们，比如苍蝇纸。相比之下，异常粘液可能就没有那么好的保护作用了。大约三分之一的女性患有细菌性阴道病(BV)，她们感染艾滋病毒和其他病毒、细菌和原虫病原体的风险增加了2-6倍。BV是一种阴道菌群的多菌体过度生长，可以杀死健康的乳酸菌，将阴道粘液转化为水状分泌物，并部分消除阴道的酸性。我们已经开发出粘液穿透颗粒(MPP)，可以揭示新鲜人体样本中粘液的网状间距。因此，我们可以识别在体外生殖器粘液中被空间封闭(病原体大小和网目间距)和/或被粘连捕获的病原体。我们的初步观察表明，来自具有健康阴道菌群的妇女的天然(酸性)宫颈阴道粘液可以粘连HPV、HIV和HSV。但是，如果用NaOH部分中和模拟BV的中和作用，HIV和HSV可以穿透这一粘液屏障。我们的总体假设是，具有健康阴道菌群的女性的粘液分泌物对病原体渗透具有高度保护作用，但这种保护在患有BV的女性中大大减弱。为了测试这一点，目标1将扩大我们的试点观察范围，包括所有通常通过STD病原体传播的粘液：宫颈内粘液、健康的宫颈阴道粘液、BV分泌物和精液。我们将使用多粒子跟踪和MPP来表征病原体经历的纳米到微米尺度上这些生殖器分泌物的介层间距和保护性粘弹性特性。目的2将确定哪些分泌物可以阻止或延缓主要性病病原体(HIV、HSV、HPV、淋球菌和沙眼衣原体)的渗透，以及哪些分泌物可以快速渗透。我们还将确定每个病原体在各种人类分泌物中所经历的确切粘度和弹性。这将提供每个病原体所经历的障碍程度的重要量化。总而言之，AIMS 1和AIMS 2的结果还将区分在每个分泌物中被空间阻断的病原体和被粘连捕获的病原体。目的3将研究乳酸和乳酸阴离子在导致STD病原体被粘液捕获中的作用。我们的试验结果表明，乳酸特定地改变了艾滋病毒和单纯疱疹病毒的表面，这可能有助于解释它们是如何被健康的粘液捕获的。这个项目可能会阐明BV引起的异常粘液分泌如何增加对广泛的病毒、细菌和原虫病原体渗透的敏感性。这一结果也可能支持使用乳酸来帮助预防BV并增强粘液分泌物的保护作用的新方法的创造

DESCRIPTION (provided by applicant): Mucus secretions from the female reproductive tract are extremely difficult to penetrate even by virus-sized objects. Why then do these barriers sometimes fail to protect against sexually transmitted pathogens? Our pilot data suggests some pathogens are too large to penetrate mucus mesh-spacing (pore size), and mucus also traps some pathogens like fly-paper before they can reach target cells. In contrast, abnormal mucus may not be so protective. About 1 in 3 women have bacterial vaginosis (BV), and they are at >2-6-fold increased risk of infection by HIV and other viral, bacterial, and protozoan pathogens. BV is a polymicrobial overgrowth of vaginal flora that decimates healthy lactobacilli, transforms vaginal mucus to a watery secretion, and partially eliminates the acidity of the vagina. We have developed mucus penetrating particles (MPP) that reveal the mucus mesh-spacing in fresh human samples. We can thus identify pathogens that are slowed in ex vivo genital mucus fluids by steric occlusion (pathogen size > mesh-spacing) and/or trapped by adhesion. Our pilot observations indicate native (acidic) cervicovaginal mucus from women with healthy vaginal flora adhesively traps HPV, HIV, and HSV. But, if partially neutralized with NaOH to mimic neutralizing actions of BV, HIV and HSV can penetrate this mucus barrier. Our overall hypothesis is that mucus secretions from women with healthy vaginal flora are highly protective against pathogen penetration, but that this protection is greatly diminished in women with BV. To test this, Aim 1 will extend our pilot observations and include all mucus secretions through which STD pathogens are usually transmitted: endocervical mucus, healthy cervicovaginal mucus, BV secretions, and semen. We will use multiple particle tracking and MPP to characterize the meshspacing and protective viscoelastic properties of these genital secretions at the nano- to micro- length scales experienced by pathogens. Aim 2 will identify the secretions that can block or retard penetration by major STD pathogens (HIV, HSV, HPV, N. gonorrhoeae and C. trachomatis), and secretions that are rapidly penetrated. We will also determine the exact viscosity and elasticity experienced by each pathogen in the various human secretions. This will provide important quantitation of the extent of impediment each pathogen experiences. Taken together, the results from Aims 1 & 2 will also distinguish pathogens blocked sterically, and those trapped adhesively, in each secretion. Aim 3 will investigate the roles of lactic acid, and lactate anions, in causing STD pathogens to be trapped by mucus. Our pilot results show lactic acid specifically alters the surfaces of HIV and HSV, and this may help explain how they are trapped by healthy mucus. This project will likely clarify how abnormal mucus secretions caused by BV increase susceptibility to penetration of a broad range of viral, bacterial, and protozoal pathogens. The results may also support the creation of new methods that use lactic acid to help prevent BV and enhance the protective effects of mucus secretions