Regulation of Sexual Biofilm Development in Candida albicans

真菌白色念珠菌是人类微生物群的一种寄生菌。它也是一种经常分离的机会致病菌，可引起多种粘膜和危及生命的全身感染。这些感染中的大多数是由于C.白念珠菌细胞存在于生物膜中-弹性，表面相关，具有独特特性的细胞群落。许多严重的感染与植入的医疗器械高度相关，这些器械为生物膜形成提供了有效的基质。 近年来的研究表明，信息素信号是一种新的促进C.白色念珠菌生物膜信息素信号传导被很好地建立起来，以编排C。白色念珠菌细胞然而，令人惊讶的是，该程序也可以诱导应答细胞粘附并经历生物膜发育。信息素可以在相反交配类型的细胞的共培养物中驱动生物膜形成。此外，该途径的自动激活甚至可以发生在单一性别培养物中，这类似地导致C.白色念珠菌细胞和生物膜发育。因此，很明显，信息素可以发挥多效性的作用，在驱动生物膜的形成由多个C。白念珠菌细胞类型，通过常规和非常规信息素信号传导途径。在这个建议中，我们试图研究信息素诱导的生物膜形成的机制，并解决它们在体内形成的可能性，使用两种哺乳动物模型的生物膜感染。该提案的两个目标是：目标1。明确信息素诱导生物膜形成的机理。我们将确定的机制，信息素信号诱导生物膜形成的C。白色念珠菌在信息素诱导的生物膜形成期间，将对一组不同的临床分离株进行转录谱分析，并通过CRISPR删除与生物膜形成有关的靶基因，并评估它们在该过程中的作用。目标2.确定信息素信号在生物膜形成中的作用。我们将使用两种不同的哺乳动物生物膜形成模型（大鼠导管模型和义齿性口炎模型）来确定信息素信号通路是否导致生物膜形成增强。 总之，这些实验的完成将揭示信息素信号通路如何影响C。白念珠菌在体外和体内。我们的方法是基于有趣的初步数据，表明在动物模型中引入两种交配类型的混合物会导致生物膜增强。如果成功的话，这个提议有可能改变我们对C的理解。白色念珠菌生物膜形成，并对治疗患者的真菌感染具有直接的临床分支。总的来说，最先进的基因组方法、分子遗传学、高分辨率显微镜、微流体模型和设计用于模拟人类生物膜感染的两种经验证的动物模型的组合提供了研究该重要临床问题的强有力的组合方法。

The fungus Candida albicans is a commensal species of the human microbiota. It is also a frequently isolated opportunistic pathogen, responsible for a variety of mucosal and life-threatening systemic infections. The majority of these infections are a result of the ability of C. albicans cells to exist in biofilms – resilient, surface-associated, communities of cells with unique properties. Many serious infections are highly correlated with implanted medical devices, which provide efficient substrates for biofilm formation. Recent studies have revealed that pheromone signaling is a novel mechanism promoting the formation of C. albicans biofilms. Pheromone signaling is well established to choreograph mating between C. albicans cells. Surprisingly, however, this program can also induce responding cells to become adherent and undergo biofilm development. Pheromones can drive biofilm formation in co-cultures of cells of opposite mating types. In addition, auto-activation of this pathway can even occur in single sex cultures, which similarly results in enhanced adherence of C. albicans cells and biofilm development. It is therefore clear that pheromones can play a pleiotropic role in driving biofilm formation by multiple C. albicans cell types, both by conventional and non-conventional pheromone signaling pathways. In this proposal, we seek to investigate the mechanism of pheromone-induced biofilm formation, and to address the potential for them to form in vivo using two mammalian models of biofilm infection. The two Aims of the proposal are: Aim 1. To define the mechanism of pheromone-induced biofilm formation. We will determine the mechanism by which pheromone signaling induces biofilm formation in C. albicans. Transcriptional profiling will be performed on a diverse set of clinical isolates during pheromone-induced biofilm formation, and target genes implicated in biofilm formation will be deleted by CRISPR and evaluated for their roles in this process. Aim 2. To determine the role of pheromone signaling on biofilm formation in vivo. We will determine if pheromone-signaling pathways lead to enhanced biofilm formation using two distinct mammalian models of biofilm formation, a rat catheter model and a denture stomatitis model. Together, completion of these experiments will reveal how pheromone-signaling pathways impact biofilm formation in C. albicans both in vitro and in vivo. Our approach is based on intriguing preliminary data that indicates that introduction of a mixture of two mating types results in enhanced biofilms in an animal model. If successful, this proposal has the potential to transform our understanding of C. albicans biofilm formation, and has direct clinical ramifications for treatment of fungal infections in patients. Overall, the combination of state- of-the-art genomic approaches, molecular genetics, high-resolution microscopy, microfluidic models, and two validated animal models designed to mimic human biofilm infections, provides a powerful combinatorial approach to studying this important clinical problem.