Oral Epithelial Cells, Candida and PMN Activation

描述(申请人提供)：口腔鹅口疮，一种粘膜生物膜感染，继续困扰着免疫功能低下的人，特别是新生儿和服用免疫抑制药物的患者，比例高得令人无法接受。虽然白色念珠菌是该病的主要病原菌，但由于其含有内源性菌群，所以其微生物生态复杂。念珠菌在口腔中与链球菌形成混合生物膜，但这些生物膜在黏膜相关或侵袭性感染过程中的作用尚不清楚。在拟议的工作中，白色念珠菌和口腔葡萄球菌将被用作模式生物，以研究非致病口腔细菌群与已建立毒力的机会真菌(如白色念珠菌)之间的致病作用。 我们的研究依赖于一种系统和全面的方法来表征宿主和病原体介导的混合机会性粘膜感染的发病机制。我们假设，增强的促炎宿主反应和增加的念珠菌毒力介导了这些微生物在口腔和食道黏膜中的致病协同作用。在目标I中，我们将表征链球菌对TLR2/4介导的宿主对混合感染的反应的影响，并检验对念珠菌-链球菌混合生物膜的夸大的促炎和中性粒细胞反应导致病理增加的假说。在AIM II中，我们将研究混合微生物群落组装和毒力的机制。链球菌葡萄糖转移酶是促进生物被膜的胞外粘液的主要酶，它的作用将被研究。在白念珠菌中，我们将鉴定控制双重群落组装的转录因子(S)。我们还将使用小鼠口腔联合感染模型，通过调节几个依赖于Rim101的毒力基因来验证这一假设，即口腔葡萄球菌通过调节几个在口腔粘膜侵袭中起重要作用的毒力基因来增加白色念珠菌的毒力。了解口腔链球菌对念珠菌毒力和粘膜炎症反应的影响，将为口腔和食道宿主生态位内真菌感染的发病机制提供重要的新见解。更重要的是，口腔细菌在发病机制中的协同作用的发现 可能对目前仅基于抗真菌药物的口腔鹅口疮的治疗具有重要的临床意义。

DESCRIPTION (provided by applicant): Oral thrush, a mucosal biofilm infection, continues to afflict an unacceptably high percentage of immunocompromised individuals, particularly neonates and patients on immunosuppressive medications. Although C. albicans is the primary etiologic pathogen, the microbial ecology of this infection is complex since it contains members of the endogenous bacterial flora. Candida forms mixed biofilms with streptococci in the oral cavities of humans but the role of these biofilms during the course of mucosa-associated or invasive infections is unknown. In the proposed work C. albicans and S. oralis will be used as model organisms to study the mucosal disease-promoting interactions of the non-pathogenic oral bacterial flora with opportunistic fungi that have established virulence, such as C. albicans. Our studies rely upon a systematic and comprehensive approach to characterize both host- and pathogen-mediated aspects of the pathogenesis of mixed opportunistic mucosal infections. We hypothesize that enhanced proinflammatory host responses and increased Candida virulence mediate a pathogenic synergy of these microorganisms in the oral and esophageal mucosa. In aim I we will characterize the influence of streptococci on the TLR2/4-mediated host response to mixed infection and test the hypothesis that the exaggerated proinflammatory and neutrophilic response to mixed Candida-streptococcal biofilms leads to increased pathology. In aim II we will examine mechanisms of mixed microbial community assembly and virulence. The role of streptococcal glucosyltransferases, major enzymes contributing to the extracellular slime that promotes biofilms, will be examined. In C. albicans we will identify the transcription factor(s) tht control dual community assembly. We will also test the hypothesis that S. oralis increases the virulence of C. albicans by modulating several Rim101-dependent virulence genes, important in oral mucosal invasion, using a mouse oral co-infection model. An understanding of the effects of oral streptococci on Candida virulence and the mucosal inflammatory response will provide important novel insights into the pathogenesis of fungal infection within the oral and esophageal host niche. More importantly, the discovery of a synergistic role for oral bacteria in pathogenesis may have important clinical implications in the treatment of oral thrush which is currently based solely on antifungals.