Lactobacilli as a source of natural microbicides against HIV-1

描述：局部杀微生物剂配制用于阴道使用可能有助于阻止进一步传播艾滋病毒-1减少妇女的新感染人数。正在考虑的一种杀微生物剂策略是加强发生HIV-1传播的阴道粘膜的天然防御。乳杆菌属是在健康女性生殖道分泌物中发现的主要肠道细菌。在厌氧条件下，这些细菌产生乳酸，某些菌株还产生过氧化氢，这是一种有效的抗菌剂，已被证明可以在体外抑制HIV-1。乳酸菌还产生一系列称为细菌素的抗菌分子，这些分子对当地环境中的竞争生物体有效。这些天然抗菌因子是否能抑制HIV-1在阴道组织中的传播和复制尚不清楚。在初步研究中，我们已经表明，条件培养基（CM）从培养的鼠李糖乳杆菌GG（LGG）抑制HIV-1的复制2至4个logs 10在原代CD 4 + T淋巴细胞，这种抗病毒活性是不同的乳酸和过氧化氢。我们假设，由阴道乳酸菌产生的天然细菌素样分子可以增强阴道粘膜的先天免疫力，并可以抑制这些靶组织中HIV-1的感染和/或复制。探索性（R21）阶段拟定的研究目标是纯化和鉴定LGG细菌产生的低分子量活性因子，并确定LGG纯化因子（LGG-PF）：1）体外抑制HIV-1的复制，2）调节细胞活化、增殖和转录调节，和3）影响来自人类女性生殖道的原代上皮细胞的先天免疫因子的分泌。在发育（R33）阶段，我们将评估LGG-PF对人类宫颈和阴道组织原代外植体培养物中HIV-1感染和先天免疫因子分泌的影响，并将进一步评估局部阴道杀微生物剂临床前评价的小鼠模型中的宫颈阴道毒性和炎症。如果LGG细菌分泌的纯化因子显示出在体外抑制相关靶细胞中的HIV-1复制，并调节女性生殖道组织外植体中先天免疫因子的表达，这将提供新的有益作用的证据，该作用远远超出这些细菌的既定抗微生物功能。此外，这些结果将为乳酸杆菌衍生产品单独或与阻断HIV-1感染和复制的靶向化合物组合作为HIV杀微生物剂的应用奠定基础。

DESCRIPTION: Topical microbicides formulated for vaginal use may help stem further spread of HIV-1 by reducing the number of new infections in women. One microbicide strategy under consideration is to strengthen the natural defenses in the vaginal mucosa where HIV-1 transmission takes place. Lactobacillus species are the predominant commensal bacteria found in genital tract secretions of healthy women. Under anaerobic conditions, these bacteria produce lactic acid and certain strains also produce hydrogen peroxide, a potent antimicrobial that has been shown to inactivate HIV-1 in vitro. Lactic acid bacteria also produce an array of antimicrobial molecules, termed bacteriocins, that are effective against competing organisms in the local milieu. Whether these natural antimicrobial factors can inhibit transmission and replication of HIV-1 in vaginal tissues is unknown. In preliminary studies, we have shown that conditioned media (CM) from cultures of Lactobacillus rhamnosus GG (LGG) inhibits replication of HIV-1 by 2 to 4 logs10 in primary CD4+ T lymphocytes, and this antiviral activity is distinct from both lactic acid and hydrogen peroxide. We hypothesize that natural bacteriocin-like molecule(s) produced by commensal lactic acid bacteria can enhance innate immuity in the vaginal mucosa and can inhibit infection and/or replication of HIV-1 in these target tissues. The goal of studies proposed in the exploratory (R21) phase is to purify and identify the low molecular weight active factor(s) produced by LGG bacteria, and determine the extent to which the LGG-purified factors (LGG-PF): 1) inhibit replication of HIV-1 in vitro, 2) modulate cell activation, proliferation and transcriptional regulation, and 3) affect the secretion of innate immune factors from primary epithelial cells from the human female reproductive tract. In the developmental (R33) phase, we will evaluate the effect of LGG-PF on HIV-1 infection and secretion of innate immune factors in primary explant cultures of human cervical and vaginal tissues, and will further evaluate cervicovaginal toxicity and inflammation in a mouse model developed for preclinical evaluation of topical vaginal microbicides. If the purified factor(s) secreted by LGG bacteria are shown to inhibit HIV-1 replication in relevant target cells in vitro, and modulate expression of innate immune factors in female genital tract tissue explants, this would provide evidence of a novel and beneficial effect that extends well beyond the established antimicrobial function of these bacteria. Moreover these results would lay the foundation for application of lactobacilli-derived products as HIV microbicides either alone or in combination with targeted compounds that block HIV-1 infection and replication.