Oral Epithelial Cells, Candida and PMN Activation

描述（由申请人提供）：鹅口疮（假膜性念珠菌病）继续困扰着不可接受的高比例的免疫功能低下的个体，特别是儿童。由于这种口腔感染的不稳定性，主要由C。白念珠菌的感染可能归因于其生物膜形成活性，了解粘膜生物膜形成的不同阶段和伴随的宿主反应对于理解这种感染的发病机制和设计有效的抗感染策略至关重要。在下一个竞争周期中，拟议研究的目标是更好地了解宿主对口腔念珠菌形成的粘膜生物膜的反应，以及促炎细胞因子和中性粒细胞在预防或消除此类生物膜中的作用。在当前的资金周期中，我们建立了一个三维口腔组织模型，该模型忠实地再现了伪膜性念珠菌病病变的组织学和细胞学特征，并纳入了中性粒细胞，以便我们可以原位检查其杀念珠菌活性。在研究这种组织类似物时，我们发现念珠菌不与口腔粘膜组织作为单细胞生物相互作用，而是形成复杂的粘膜生物膜。我们能够复制和验证口腔食管念珠菌病小鼠模型中粘膜组织生物膜的存在。本申请将建立在当前资助周期期间产生的数据的基础上，以解决以下目标：a）表征口腔粘膜中生物膜的发育阶段、细胞组成和空间排列，并测试念珠菌组织生物膜影响粘膜促炎细胞因子对感染的反应的假设; B）检验嗜中性粒细胞抗念珠菌应答在生物膜环境内被抑制的假设，并检查这种抑制的机制;和c）研究特异性念珠菌基因产物在促进口腔粘膜生物膜形成、组织侵袭和损伤中的作用。由于浅表真菌病的特点是在复层上皮表面形成念珠菌生物膜，影响其他胃肠道粘膜部位，如食管粘膜，这可能更容易受到侵袭，我们的研究可能对预防播散性感染有深远的影响。我们设想我们的研究将导致开发新的口服抗真菌药物，其靶向通过C.促进局部中性粒细胞抗真菌功能。公共卫生意义：口腔假膜性念珠菌病仍然是免疫系统减弱或不成熟的患者（如HIV阳性儿童、新生儿和恶性肿瘤患者）中最常见的念珠菌感染形式。我们认为，在这种感染中，生物膜为念珠菌提供了一个保护环境，使其免受先天防御机制的影响，这可能会促进其持久性。我们设想，我们在组织生物膜的研究将导致新的口服抗真菌药物的发展，目标生物膜调节的途径，由C。促进中性粒细胞抗真菌功能。

DESCRIPTION (provided by applicant): Oral thrush (pseudomembranous candidiasis) continues to afflict an unacceptably high percentage of immunocompromised individuals, particularly children. Since the recalcitrant nature of this oral infection, triggered primarily by C. albicans, could be attributed to its biofilm forming activities, knowledge of the distinct stages in mucosal biofilm formation and concomitant host responses is of paramount importance in understanding the pathogenesis of this infection and designing effective anti-infective strategies. The goals of the proposed studies in the next competitive cycle are directed toward a better understanding of the host response to mucosal biofilms formed by Candida in the oral cavity and the role of proinflammatory cytokines and neutrophils in the prevention or elimination of such biofilms. In the current funding cycle we established a three-dimensional oral tissue model which faithfully reproduces the histologic and cellular characteristics of pseudomembranous candidiasis lesions and incorporated neutrophils so that we can examine their candidacidal activities in situ. While working with this tissue analogue we discovered that Candida does not interact with oral mucosal tissues as single cell organisms, but forms a complex mucosal biofilm. We were able to reproduce and validate the presence of a mucosal tissue biofilm in a mouse model of oroesophageal candidiasis. This application will build on data generated during the current funding cycle to address the following Aims: a) characterize the stages in development, cellular composition and spatial arrangement of biofilms in the oral mucosa and test the hypothesis that Candida tissue biofilms affect the mucosal proinflammatory cytokine response to infection; b) test the hypothesis that neutrophil anti-Candida responses are inhibited within the biofilm environment and examine the mechanisms of this inhibition; and c) investigate the role of specific Candida gene products in facilitating oral mucosal biofilm formation, tissue invasion and damage. Since superficial mycoses characterized by Candida biofilm formation on the surface of stratified epithelia affect other GI tract mucosal sites, such as the esophageal mucosa, which may be more vulnerable to invasion our studies may have far reaching implications in preventing disseminated infection. We envision that our studies will lead to the development of new oral anti-mycotic agents which target pathways of mucosal biofilm regulation by C. albicans and promote local neutrophil antifungal functions. Public Health Significance: Oral pseudomembranous candidiasis is still the most prevalent form of Candida infection in patients with weakened or immature immune systems, such as HIV+ children, neonates and patients with malignancies. We propose that in this infection biofilms provide a protective environment for Candida from innate defense mechanisms, which may promote its persistence. We envision that our studies in tissue biofilms will lead to the development of new oral anti-mycotic agents which target pathways of biofilm regulation by C. albicans and promote neutrophil antifungal functions.