Candida albicans responses to antifungals and cell wall stress

白色念珠菌引起侵袭性感染，如念珠菌血症和腹腔内念珠菌病（IAC）， 常见于住院患者。梭白念珠菌细胞壁是念珠菌病发病机制的核心，但 细胞壁调节和毒力之间的联系机制才刚刚开始被理解。细胞壁活性 棘白菌素抗真菌剂是对抗侵袭性念珠菌病的一线药物。然而， 用棘白菌素治疗的念珠菌血症或IAC患者为40%或更高。我们证明了C. 白色念珠菌迅速离域磷脂酰肌醇-（4，5）-二磷酸（PI（4，5）P2）和septins作为天然 对棘白菌素的反应有针对性地破坏C.白色念珠菌INP 51，其编码PI（4，5）P2特异性5 '- 磷酸酶，导致PI（4，5）P2和septin失调，棘白菌素过敏，过度激活 PKC-Mkc 1细胞壁完整性途径在应激反应中的作用，细胞壁损伤基因表达谱 缺乏压力，并在血源性播散性念珠菌病（DC）和IAC期间减弱毒力， 小鼠我们的数据表明，平衡的PI（4，5）P2调节促进保护性细胞壁反应， 通过激活PKC-Mkc 1途径，而PI（4，5）P2失调与 有害的细胞分裂素、质膜和细胞壁反应。最近，我们建立了C。白色 CAS 5，其编码Inp 51和Mkc 1下游的主要转录因子，以及RIM 101，其编码 在pH>5.5，IAC期间和inp 51突变体中诱导的转录因子，是 棘白菌素反应和毒力。本项目的目标是确定C. 白色念珠菌CAS 5和RIM 101调节细胞壁应激反应并有助于棘白菌素抗性， 侵袭性念珠菌病的发病机制。目的一是验证C.白色念珠菌CAS 5 IAC作为毒力决定因子，并对其生物学功能进行了研究.为了达到这些目的，我们将使用RNA-Seq 进行cas 5无效突变体和CAS 5重建菌株的体外和时间转录谱分析， 在小鼠的IAC期间在空间上。然后，我们将通过以下方式验证某些Cas 5调控的基因作为毒力决定因子： 在IAC和DC小鼠模型中测试突变株，并表征其功能。在目标2中，我们 使用类似的方法来验证在IAC期间由RIM 101调控的基因作为毒力决定因素，并确定 它们的功能。在目标3中，我们将鉴定由C.白色念珠菌CAS 5和RIM 101响应于 米卡芬净在IAC中的作用，并验证它们在棘白菌素耐药或敏感性中的作用。我们将执行 RNA-Seq转录谱分析C.白色念珠菌野生型SC 5314、cas 5、rim 101和相应的重建 在体外和IAC期间对米卡芬净有反应的菌株，并验证某些基因对米卡芬净有贡献 体内反应。本项目将为棘白菌素和细胞壁应激反应提供新的见解。 白色念珠菌，与侵袭性念珠菌病的治疗和发病机制有关， 以确定新的治疗和诊断目标。

Candida albicans causes invasive infections like candidemia and intra-abdominal canididiasis (IAC) that are common among hospitalized patients. The C. albicans cell wall is central to the pathogenesis of candidiasis, but mechanisms that link cell wall regulation and virulence are only beginning to be understood. Cell wall-active echinocandin antifungals are front-line agents against invasive candidiasis. However, mortality rates among patients with candidemia or IAC who are treated with echinocandins are 40% or higher. We have shown that C. albicans rapidly delocalizes phosphatidylinositol-(4,5)-bisphosphate (PI(4,5)P2) and septins as part of the natural response to echinocandins. Targeted disruption of C. albicans INP51, which encodes a PI(4,5)P2-specific 5'- phosphatase, results in PI(4,5)P2 and septin dysregulation, echinocandin hypersusceptibility, over-activation of the PKC-Mkc1 cell wall integrity pathway in response to stress, cell wall damage gene expression profiles in absence of stress, and attenuated virulence during hematogenously disseminated candidiasis (DC) and IAC in mice. Our data demonstrate that balanced PI(4,5)P2 regulation promotes protective cell wall responses and virulence through activation of the PKC-Mkc1 pathway, while PI(4,5)P2 dysregulation is associated with deleterious septin, plasma membrane and cell wall responses. More recently, we established that C. albicans CAS5, which encodes a major transcription factor downstream of Inp51 and Mkc1, and RIM101, which encodes a transcription factor induced at pH>5.5, during IAC and in the inp51 mutant, are important determinants of echinocandin responses and virulence. The objectives of this project are to determine mechanisms by which C. albicans CAS5 and RIM101 regulate cell wall stress responses and contribute to echinocandin resistance and the pathogenesis of invasive candidiasis. In aim 1, we will validate genes regulated by C. albicans CAS5 during IAC as virulence determinants, and identify their biologic functions. Toward these ends, we will use RNA-Seq to perform transcriptional profiling of cas5 null mutant and CAS5 reconstitution strains in vitro and temporal- spatially during IAC of mice. Then, we will validate certain Cas5-regulated genes as virulence determinants by testing mutant strains in the mouse models of IAC and DC, and characterize their functions. In aim 2, we will use similar approaches to validate genes regulated by RIM101 during IAC as virulence determinants, and identify their functions. In aim 3, we will identify genes regulated by C. albicans CAS5 and RIM101 in response to micafungin during IAC, and validate their roles in echinocandin resistance or susceptibility. We will perform RNA-Seq transcriptional profiling of C. albicans wild-type SC5314, cas5, rim101 and the respective reconstitution strains in response to micafungin in vitro and during IAC, and validate certain genes as contributing to micafungin responses in vivo . This project will provide new insights into echinocandin and cell wall stress responses by C. albicans that are relevant to the treatment and pathogenesis of invasive candidiasis, and which have the potential to identify new therapeutic and diagnostic targets.