Pathogen trapping by genital mucus secretions

描述（由申请人提供）：女性生殖道的粘液分泌物即使被病毒大小的物体也极难穿透。那么，为什么这些屏障有时不能防止性传播病原体呢？我们的试点数据表明，一些病原体太大而无法穿透黏液的网距（孔径），黏液也会在病原体到达目标细胞之前将它们像苍蝇纸一样困住。相反，异常的粘液可能没有那么强的保护作用。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、细菌和原生动物病原体的风险增加了2-6倍。细菌性阴道炎是一种阴道菌群的多微生物过度生长，大量杀灭健康的乳酸菌，将阴道粘液转化为水样分泌物，并部分消除阴道的酸性。我们已经开发出粘液穿透颗粒（MPP）来揭示新鲜人体样本中的粘液网间距。因此，我们可以识别出在体外生殖器黏液中通过空间位阻（病原体大小为100网距）和/或通过粘附被阻滞的病原体。我们的初步观察表明，来自健康阴道菌群的女性的天然（酸性）宫颈阴道粘液粘附性地捕获HPV， HIV和HSV。但是，如果用NaOH部分中和以模仿BV的中和作用，HIV和HSV可以穿透这个粘液屏障。我们的总体假设是，阴道菌群健康的女性的粘液分泌物对病原体的渗透具有很强的保护作用，但这种保护作用在感染细菌性阴道炎的女性中大大减弱。为了验证这一点，Aim 1将扩展我们的试点观察，并包括性病病原体通常通过的所有粘液分泌物：宫颈粘液、健康的宫颈阴道粘液、细菌性阴道炎分泌物和精液。我们将使用多粒子跟踪和MPP来表征病原体在纳米到微尺度上这些生殖器分泌物的网格间距和保护性粘弹性特性。目标2将确定能够阻止或延缓主要性病病原体（艾滋病毒、HSV、HPV、淋病奈瑟菌和沙眼衣原体）渗透的分泌物，以及迅速渗透的分泌物。我们还将确定每种病原体在各种人类分泌物中所经历的确切粘度和弹性。这将为每种病原体所受的阻碍程度提供重要的定量。综上所述，Aims 1和Aims 2的结果也将区分每种分泌物中被立体阻断的病原体和被粘附性捕获的病原体。目的3将研究乳酸和乳酸阴离子在引起STD病原体被粘液捕获中的作用。我们的试验结果显示乳酸特异性地改变了HIV和HSV的表面，这可能有助于解释它们是如何被健康的粘液所捕获的。该项目可能会阐明由细菌性阴道炎引起的异常粘液分泌物如何增加对广泛的病毒、细菌和原生动物病原体渗透的敏感性。该结果也可能支持使用乳酸帮助预防细菌性脑膜炎和增强粘液分泌物保护作用的新方法的创建

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 PUBLIC HEALTH RELEVANCE: Women with healthy vaginal flora (lactobacilli) are at markedly less risk of HIV, HSV, HPV, and several STD bacteria and protozoa than women with bacterial vaginosis (BV). Unfortunately, only a minority of women (<40%) have healthy vaginal flora and at any given time about 1 in 3 women have BV. This project will help reveal how healthy vaginal flora helps protect against infection and how BV increases susceptibility to infections; the results will likely support developing vaginal products and microbicides that reinforce the broad- spectrum protective actions of vaginal lactic acid.