SUPEROXIDE DISMUTASE OF CRYPTOCOCCUS NEOFORMANS

新型隐球菌超氧化物歧化酶

• 批准号: 6313655
• 负责人: SUDHA CHATURVEDI
• 金额: $ 21.6万
• 依托单位: WADSWORTH CENTER
• 依托单位国家: 美国
• 财政年份: 2001
• 资助国家: 美国
• 起止时间: 2001-01-01 至 2004-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6313655
• 关键词: Cryptococcus neoformans; animal breeding; antioxidants; clinical research; disease /disorder model; enzyme activity; enzyme induction /repression; enzyme mechanism; genetic regulation; genetically modified animals; host organism interaction; human subject; laboratory mouse; male; molecular genetics; oxidative stress; phagocytes; postmortem; stress; superoxide dismutase; tissue /cell culture

DESCRIPTION: Cryptococcus neoformans (Cn), a facultative intracellular yeast, is a serious cause of meningoencephalitis in normal and immunocompromised patients. The susceptibility of immunocompromised patients to cryptococcosis may be related to intrinsic defects in the functions of phagocytic cells combined with impaired T cell functions. The host immune defense against Cn has been extensively studied. However, few studies are available defining how Cn protects itself against human phagocytes. There is preliminary evidence that CuZn-SOD (product of SOD1 gene) act as antioxidant at permissive temperature of 37 degreeC. In addition, a significant reduction in Cn neutrophil killing by exogenous addition of SOD suggests a possible role for CuZn-SOD against phagocytic killing. Therefore, the central hypotheses to be tested in this project are that; 1) CuZn-SOD is an accessory pathogenic factor that enables Cn yeast to survive intracellular killing by phagocytes and, 2) the regulation, expression and cellular localization of CuZn-SOD is of critical importance in Cn response to host oxidative burst. The cDNA and genomic DNA of SOD1 from Cn yeast were recently cloned by functional complementation of SOD1delta mutant of Saccharomyces cerevisiae and by Southern hybridization of cosmid library using Cn SOD1 cDNA as a probe. The deduced 154 amino acid sequence of Cn SOD1 cDNA showed approximately 62 percent identity with other fungal SODs. This preliminary data will be the basis for the proposed study which aims at (i) construction of SOD1 knockout and revertant mutants to define the phenotypic and biochemical consequences of CuZn-SOD deficiency and its role in animal virulence (ii) determination of protective mechanisms of CuZn-SOD against oxidative damage produced by human phagocytes in vitro, (iii) regulation of SOD] transcripts and proteins during oxidative and other stress conditions to define the role of this oxidant in Cn biology. These studies are potentially significant because the results are expected to (a) define the precise antioxidant role of CuZn-SOD, (b) characterize the mechanism used by Cn to survive under oxidative stress, (c) expand understanding of host-pathogen interactions in cryptococcosis, which may aid in improved design of drugs and or vaccines, and (d) provide methodological basis for study of other fungal antioxidants.

描述：辅助细胞内酵母菌（ 是正常和免疫功能低下的脑膜脑炎的严重原因 患者。免疫功能低下的患者对隐球菌病的敏感性 可能与吞噬细胞功能的固有缺陷有关 结合T细胞功能受损。主机免疫防御CN已 被广泛研究。但是，很少有研究可以定义CN 保护自己免受人类吞噬细胞的侵害。有初步证据表明 Cuzn-SOD（SOD1基因的产物）在允许温度下起到抗氧化作用 37 degreec。另外，通过 SOD的外源性添加表明Cuzn-Sod可能起作用 吞噬杀戮。因此，在此中要检验的中心假设 项目是； 1）Cuzn-Sod是一种辅助病原因子，可实现CN 酵母可在吞噬细胞杀死细胞内杀害，2）调节， Cuzn-SOD的表达和细胞定位在 CN对宿主氧化爆发的反应。来自CN的SOD1的cDNA和基因组DNA 最近，通过sod1delta突变体的功能互补来克隆酵母 酿酒酵母和宇宙文库的南部杂交使用Saccharomyces CN SOD1 cDNA作为探针。推导的154个CN SOD1 cDNA的氨基酸序列 与其他真菌草皮显示约62％的身份。这 初步数据将是拟议研究的基础，该研究旨在（i） SOD1敲除和恢复突变体的构建以定义表型 以及库兹尼 - 模化缺乏及其在动物中的作用的生化后果 毒力（ii）确定库兹尼的保护机制 人吞噬细胞在体外产生的氧化损伤，（iii）调节 SOD]在氧化和其他应力条件期间的转录本和蛋白质 定义该氧化剂在CN生物学中的作用。这些研究可能是 意义重大，因为预期结果将（a）定义精确 Cuzn-Sod的抗氧化作用，（B）表征CN使用的机制 在氧化应激下生存，（c）扩大对宿主病原的理解 隐球菌病中的相互作用，这可能有助于改善药物的设计和 或疫苗，（d）为研究其他真菌提供方法论基础 抗氧化剂。