Characterization of novel virulence factors in Candida

摘要 白念珠菌是大多数微生物区系中唯一的共生成分。 人类，不会对我们大多数人造成伤害，但它会引起从轻微到生命的一系列感染- 基于宿主的免疫状态，具有威胁性。白念珠菌与白念珠菌的相互作用 哺乳动物吞噬细胞是至关重要的，念珠菌-巨噬细胞共培养已成为一种 发现促进毒力和共生的特定适应的宝贵模式。至 进一步探索这种相互作用的新生物学，我们使用转录图谱来鉴定 吞噬时诱导的真菌基因。虽然其中一些具有可识别的功能， 大部分在新陈代谢(已知的对吞噬作用的反应)中，超过一半的诱导基因 没有特征，也没有得到广泛的保护。这些基因中有数量惊人的是 小，在早期的注释中遗漏了。鉴于白念珠菌的独特性--人类 关联，这组基因可能是丰富的，以适应白色念珠菌的宿主生态位。在……里面 证明了这一原理，我们已经突变了这些基因中的三个，并且这三个基因都与宿主相关 表型，其中一种是一种新的与细胞壁相关的微粘附素，需要与 生物和非生物表面以及小鼠模型中的毒力。我们建议将其集群 常规粘附素进入细胞表面的异质复合体，增强了细胞表面的强度 结合到底物上。另外两种虽然很小，但同样具有抗氧化特性。 蛋白质(68和99个氨基酸)。因此，它们是功能的独特调停者 被认为对念珠菌的毒力(粘附性和抗氧化性)至关重要。我们 建议进行研究，以辨别这两种表型背后的机制细节。基于 我们的初步基因分析的成功，我们建议进行更大规模的努力，以产生 所有未鉴定的巨噬细胞诱导基因的突变文库，并在多个 体外、体外和体内检测。这项建议的优势在于我们在分析 这种关键的宿主-病原体相互作用，我们彻底的遗传方法和筛查方案， 以及多种动物模型的使用。创新潜力巨大，因为重点是 寄主-病原体界面的新基因和新生物学。这项提议的结果是 对基因功能的更深层次和更广泛的理解 真菌的共生性和致病性。

Abstract Candida albicans is uniquely associated as a commensal component of the microbiota of most humans, without harm to most of us, yet it causes a range of infections from mild to life- threatening, based on the immune status of the host. The interaction between C. albicans and mammalian phagocytes is critical, and the Candida-macrophage co-culture has become a valuable model to uncover specific adaptations that promote virulence and commensalism. To further probe the novel biology of this interaction, we used transcriptional profiling to identify fungal genes induced upon phagocytosis. While some of these have recognizable functions, mostly in metabolism (a known response to phagocytosis), more than half the induced genes are uncharacterized and not widely conserved. A surprising number of these genes are quite small and missed in early annotations. Given the uniqueness of the C. albicans-human association, this set of genes is likely enriched for adaptations of C. albicans to host niches. In proof of this principle, we have mutated three of these genes and all three have host-relevant phenotypes, with one as a novel cell wall-associated microadhesin required for adhesion to biotic and abiotic surfaces and for virulence in mouse models. We propose that it clusters conventional adhesins into heterogeneous complexes on the cell surface that strengthens binding to substrates. Two others have antioxidant properties, again despite being quite small proteins (68 and 99 amino acids). These are therefore unique mediators of functions appreciated to be critical for Candida virulence (adhesion and oxidative stress resistance). We propose studies to discern the mechanistic details underlying both phenotypes. Based on the successes of our preliminary genetic analysis, we propose a larger-scale effort to generate a mutant library of all of the uncharacterized macrophage-induced genes and test them in multiple in vitro, ex vivo, and in vivo assays. The strength of this proposal is in our expertise in analyzing this critical host-pathogen interaction, our thorough genetic methods and screening protocols, and the use of multiple animal models. The innovative potential is significant given the focus on novel genes and novel biology at the host-pathogen interface. The outcome of this proposal is a deeper and broader understanding of the genetic functions that are required for commensalism and pathogenicity in fungi.