Small molecule inhibitors of a Candida albicans histone modifying enzyme

白色念珠菌组蛋白修饰酶的小分子抑制剂

• 批准号: 8008804
• 负责人: Jessica Ramos Lopes da Rosa-Spiegler
• 金额: $ 2.63万
• 依托单位: UNIV OF MASSACHUSETTS MED SCH WORCESTER
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-01-20 至 2013-01-19
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8008804
• 关键词: Acetylation; Acquired Immunodeficiency Syndrome; Antibodies; Antifungal Agents; Biochemical; Biological Assay; Candida; Candida albicans; Candidiasis; Cells; Chemicals; Development; Enzymatic Biochemistry; Enzyme-Linked Immunosorbent Assay; Enzymes; Eukaryota; Eukaryotic Cell; Family; Funding; Gene Expression; Genes; Genetic Transcription; Genome Stability; Goals; Growth; Health; Histone Acetylation; Histone H3; Histones; Homologous Gene; Human; Immunocompromised Host; In Vitro; Individual; Infection; Laboratories; Laboratory Research; Lysine; Mammalian Cell; Massachusetts; Measures; Microbial Genetics; Modeling; Mus; Mutagens; Mycoses; Pathogenesis; Pathogenicity; Pathology; Patients; Phagosomes; Physiological; Predisposition; Proteins; Protocols documentation; Reactive Oxygen Species; Recombinants; Research; Resistance; Role; Saccharomyces cerevisiae; Saccharomycetales; Screening procedure; Stress; Systemic infection; Testing; Therapeutic; Therapeutic Intervention; Tissues; Toxic effect; Training; Universities; Virulence; Virulence Factors; Yeasts; base; combat; fungus; high throughput screening; histone acetyltransferase; histone modification; in vivo; inhibitor/antagonist; killings; macrophage; medical schools; microbial; mortality; mutant; novel; novel therapeutic intervention; pathogen; pre-doctoral; research study; response; small molecule; small molecule libraries

DESCRIPTION (provided by applicant): Candida albicans is a widespread human fungal pathogen that causes high rates of mortality during systemic infections, and is particularly dangerous for immunocompromised AIDS patients. Because fungi such as C. albicans are eukaryotes, development of antifungal therapeutics that is non-toxic to humans is often challenging. Recently, RU109 was identified as the enzyme that catalyzes acetylation of histone H3 lysine 56 in the budding yeast, Saccharomyces cerevisiae. Mutants lacking Rtt109 are viable, but is slow growing and extremely sensitive to genotoxic agents. Notably, no close homologs of RTT109 genes are found outside of fungal species, and Rtt109 proteins do not contain signature residues found in the other families of histone acetyltransferase (HAT) enzymes. Therefore, we hypothesize that we can identify small molecules that inhibit Rtt109 function without substantial effect on other HAT enzymes. Furthermore, as Rtt109 homologs are restricted to fungi, they represent promising targets for small molecule therapeutic intervention with minimal toxicity for mammalian hosts. In this revised proposal, I aim to elucidate the role of Rtt109 in pathogenesis by C. albicans and to discover Rtt109 inhibitory compounds that are efficient in vivo. I have confirmed the functional conservation of the C. albicans Rtt109 enzyme, because it is essential for H3K56 acetylation and for resistance to genotoxic agents. I will test whether C. albicans rtt109-/- mutants display increased sensitivity to macrophages in vitro and whether they are pathogenic in the established murine candidiasis model. Second, I will screen a library of small molecules for inhibition of histone acetylation by Rtt109 in vitro. To do this, we have developed a high-throughput assay which will allow quantitative assessment of histone acetylation by purified, recombinant Rtt109, detected with an anti-H3K56-acetyl antibody. Finally, I will begin to characterize candidate compounds that are non-toxic to mammalian cells for their effects on histone modification in Candida, and on pathogenesis in mice. PUBLIC HEALTH RELEVANCE: Candida albicans is a pathogenic fungus that is particularly dangerous to immunocompromised individuals, including AIDS patients. Recently, a new enzyme was discovered that is important for normal growth of fungi. I propose to study how this enzyme contributes to growth and virulence of Candida albicans. I will also identify compounds that inhibit this enzyme, with the goal of developing new therapeutic approaches to combat fungal infections.

描述（申请人提供）：白色念珠菌是一种广泛存在的人类真菌病原体，在全身感染期间导致高死亡率，对于免疫功能低下的艾滋病患者尤其危险。由于真菌如C.白色念珠菌是真核生物，开发对人类无毒的抗真菌疗法往往具有挑战性。最近，RU 109被鉴定为在芽殖酵母（Saccharomyces cerevisiae）中催化组蛋白H3赖氨酸56乙酰化的酶。缺乏Rtt 109的突变体是可行的，但生长缓慢，对遗传毒性剂极其敏感。值得注意的是，在真菌物种之外没有发现RTT 109基因的同源物，并且Rtt 109蛋白不包含在组蛋白乙酰转移酶（HAT）酶的其他家族中发现的特征残基。因此，我们假设，我们可以识别小分子抑制Rtt 109功能，而对其他HAT酶没有实质性的影响。此外，由于Rtt 109同源物仅限于真菌，它们代表了对哺乳动物宿主具有最小毒性的小分子治疗干预的有希望的靶标。 在这个修订的建议中，我的目的是阐明Rtt 109在C.白色念珠菌，并发现在体内有效的Rtt 109抑制化合物。证实了C.白色念珠菌Rtt 109酶，因为它是H3 K56乙酰化和耐遗传毒性剂所必需的。我将测试C。白色念珠菌RTT 109-/-突变体在体外显示出对巨噬细胞的敏感性增加，以及它们在建立的鼠念珠菌病模型中是否是致病性的。第二，我将在体外筛选一个小分子库，用于Rtt 109抑制组蛋白乙酰化。为此，我们开发了一种高通量测定法，该测定法将允许通过纯化的重组Rtt 109定量评估组蛋白乙酰化，用抗H3 K56-乙酰基抗体检测。最后，我将开始描述候选化合物，这些化合物对哺乳动物细胞无毒，对念珠菌组蛋白修饰和小鼠发病机制有影响。 公共卫生相关性：白色念珠菌是一种致病性真菌，对免疫功能低下的人特别危险，包括艾滋病患者。最近，发现了一种新的酶，对真菌的正常生长很重要。我建议研究这种酶如何促进白色念珠菌的生长和毒力。我还将确定抑制这种酶的化合物，目的是开发新的治疗方法来对抗真菌感染。