ER stress and virulence of Aspergillus fumigatus

描述(申请人提供)：烟曲霉是一种重要的机会性真菌病原体，已成为免疫功能低下患者的主要感染模式。尽管在治疗方面取得了一些进展，但侵袭性曲霉病的预后仍然很差，这强调了需要更多关于真菌途径的信息，这些途径对生物在体内的生长至关重要。作为正常腐生生活方式的一部分，烟曲霉会分泌大量的胞外蛋白质，这使其处于蛋白质展开和内质网(ER)应激的高风险中。未折叠蛋白反应(UPR)通过上调参与蛋白质折叠、分泌和降解的基因的表达来对抗这种压力。在这项资助中，我们提供了烟曲霉菌严重依赖UPR来支持其在内质网应激中生存并从宿主组织中获取营养所需的分泌活动的初步数据。其次，我们证明了UPR功能的丧失与现有的抗真菌药物对烟曲霉菌具有很强的协同作用。使用UPR和相关的ER相关降解途径(ERAD)的突变体，我们建议验证ER应激反应作为曲霉病的治疗靶点，并深入了解反应的关键成分。目的验证UPR在内质网应激条件下对烟曲霉的生长是必需的，并有助于机体在体内致病的假说。AIM II将测试ERAD也是在内质网应激条件下维持生长所必需的假设，并且它与UPR协同工作以支持体内生物体的毒力。目的III将使用全基因组方法，通过检验烟曲霉菌对内质网应激反应涉及转录和翻译的特定变化这一假说，来鉴定内质网应激反应的新成分。这些研究有可能为曲霉病的治疗确定新的靶点，并对提高对现有抗真菌药物具有内在耐药性的真菌物种的抗真菌敏感性具有更广泛的影响。

DESCRIPTION (provided by applicant): Aspergillus fumigatus is an important opportunistic fungal pathogen that has become the leading infectious mould of immunocompromised patients. Despite some advances in therapy, invasive aspergillosis continues to have a poor outcome, emphasizing the need for more information on fungal pathways that are essential to the growth of the organism in vivo. A. fumigatus secretes tremendous quantities of extracellular proteins as part of its normal saprophytic lifestyle, which places it at high risk for protein unfolding and endoplasmic reticulum (ER) stress. The unfolded protein response (UPR) counters this stress by upregulating the expression of genes involved in protein folding, secretion and degradation. In this grant, we provide preliminary data that A. fumigatus relies heavily upon the UPR to support the secretory activity that it needs to survive ER stress and acquire nutrients from host tissue. Secondly, we demonstrate that loss of UPR function exhibits potent synergism with existing antifungal drugs against A. fumigatus. Using mutants of the UPR and the related ER- associated degradation pathway (ERAD), we propose to validate ER stress responses as a therapeutic target for aspergillosis, and to gain insight into the key components of the response. The following specific Aims are proposed: Aim I will test the hypothesis that the UPR is essential for the growth of A. fumigatus under conditions of ER stress, and that it contributes to the ability of the organism to cause disease in vivo. Aim II will test the hypothesis that ERAD is also required to sustain growth under conditions of ER stress, and that it works in concert with the UPR to support the virulence of the organism in vivo. Aim III will use a genome-wide approach to identify novel components of the A. fumigatus ER stress response by testing the hypothesis that the response of A. fumigatus to ER stress involves specific changes in the transcription and translation of a subset of mRNAs. These studies have the potential to identify novel targets for the treatment of aspergillosis, and have broader implications for increasing the antifungal susceptibility profile of fungal species that are intrinsically resistant to existing antifungals.