Compounds that block a novel Candida albicans target

阻断新型白色念珠菌靶标的化合物

• 批准号: 10335276
• 负责人: JULIA R KOEHLER
• 金额: $ 47.63万
• 依托单位: BOSTON CHILDREN'S HOSPITAL
• 依托单位国家: 美国
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-02-01 至 2024-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10335276
• 关键词: Amphotericin; Antifungal Agents; Antifungal Therapy; Antiviral Agents; Binding; Biological; Biological Assay; Candida; Candida albicans; Candidiasis; Cell Wall; Cell membrane; Cell surface; Cells; Centers for Disease Control and Prevention (U.S.); Cessation of life; Chemicals; Chemosensitization; Clinical; Collection; Data; Defect; Development; Disseminated candidiasis; Dose; Drug Efflux; Drug Exposure; Drug Kinetics; Drug Targeting; Engineering; Ensure; Enzymes; FDA approved; Fluorescence; Foscarnet; Fungal Drug Resistance; Genetic; Goals; Gold; Grant; Growth; Human; Infection; Inorganic Phosphate Transporter; Ion Channel; Lead; Libraries; Life Cycle Stages; Micafungin; Modeling; Multi-Drug Resistance; Mus; Mycoses; New Mexico; Organ; Oxidative Stress; Patients; Pharmaceutical Chemistry; Pharmaceutical Preparations; Pharmacodynamics; Pharmacology; Phase; Property; Proteins; Reagent; Reporter; Resistance; Resistance development; Role; Saccharomyces cerevisiae; Sampling; Signal Pathway; Sirolimus; Stress; Structure; Structure-Activity Relationship; System; Testing; Toxic effect; Triage; Tube; Universities; Validation; Virulence; Virulence Factors; Work; analog; attributable mortality; chemical property; design; drug discovery; efflux pump; experimental study; fungus; high throughput screening; in vivo; inhibitor; inorganic phosphate; interest; lead candidate; mouse model; new therapeutic target; novel; pathogen; pathogenic fungus; pressure; receptor; resistance mechanism; resistance mutation; screening; small molecule inhibitor

SUMMARY/ABSTRACT Candida albicans is the most common pathogen causing invasive fungal infections. These infections are dreaded complications of serious illnesses, and are estimated to lead to death in about 20% of patients. There are very few treatment options for fungal infections. This is because many cellular components whose function could be disrupted by drugs are similar between fungi and humans, leading to unacceptable toxicities to human cells. We have identified a potential drug target in C. albicans which has no human homologs, and whose inactivation leads to potentiation of drugs in 2 of the 3 major antifungal classes. This target is conserved among 3 phyla of pathogenic fungi, suggesting that small-molecule inhibitors could potentiate antifungal activity against other fungal pathogens. Because it is a cell-surface transporter, inhibitors of this target are not susceptible to a major multidrug-resistance mechanism of C. albicans, the induction of drug efflux pumps. Other features that render it impervious to development of resistance are that it is not an essential protein, diminishing the selective pressure during drug exposure, and that part of the mechanisms of action of its inhibitors may be its role in virulence activities of the fungus. Virulence factors like hyphal growth and oxidative stress resistance are not required during commensal growth, which comprises the majority of the C. albicans life cycle. We engineered a C. albicans strain in which inhibition of our target of interest induces GFP expression. This reporter strain is amenable to high-throughput screening using the HyperCyt platform developed at The University of New Mexico. We propose to screen library collections of chemically well-defined compounds with desirable physicochemical properties, and with existing data for other indications. Active compounds identified in the screen will be prioritized by their effect in potentiating the “gold standard” antifungal amphotericin, by their potency in blocking virulence factors (e.g. hyphal growth), as well as their toxicity window. In addition, prioritization will involve compound physicochemical properties, chemical tractability, and binding efficiencies using state-of-the-art post-screen triage approaches. Further validation tests will employ an engineered “test tube cell” Saccharomyces cerevisiae strain, in which the target is expressed at the plasma membrane as the only transporter of its substrate. Structure-activity relationships for chemotypes of prioritized hits will be established early. Hit-to-lead medicinal chemistry will be performed on prioritized hits with a focus on low host cell toxicity and physicochemical properties that support the advancement of compounds into in vivo pharmacokinetics and efficacy experiments. This project will provide high-quality lead compounds for further development as an antifungal potentiator, and potentially as a virulence-modifying single agent.

摘要/摘要 白色念珠菌是引起侵袭性真菌感染的最常见病原体。这些感染是 严重疾病的可怕并发症，估计会导致约20%的患者死亡。那里 对于真菌感染的治疗选择非常少。这是因为许多细胞组件的功能 可能被药物破坏在真菌和人类之间是相似的，导致对人类不可接受的毒性 细胞。我们已经在白色念珠菌中确定了一种潜在的药物靶点，它没有人类同源物，而且它的 灭活导致3种主要抗真菌药物中的2种药物增强。这一目标在 3门病原真菌，提示小分子抑制剂可以增强抗真菌活性。 其他真菌病原体。因为它是一种细胞表面转运蛋白，所以这个靶点的抑制剂不容易受到 白色念珠菌的主要耐药机制是诱导药物外排泵。其他功能 使其不受抗药性发展的影响是，它不是一种必需的蛋白质，降低了选择性 药物暴露过程中的压力，其抑制剂作用机制的一部分可能是它在 该真菌的毒力活性。像菌丝生长和抗氧化性这样的毒力因子不是 在白念珠菌生命周期中占大多数的共生生长过程中所需的。 我们设计了一株白色念珠菌，在该菌株中，抑制我们感兴趣的靶标会诱导GFP表达。这 报告菌株可以使用由美国国家卫生研究院开发的HyperCyt平台进行高通量筛选 新墨西哥大学。我们建议用以下方法筛选化学定义明确的化合物的文库收藏 理想的物理化学特性，以及其他适应症的现有数据。鉴定出的活性化合物 在屏幕上将优先考虑它们在增强抗真菌两性霉素的“黄金标准”方面的效果，通过它们的 阻断毒力因子的效力(例如菌丝生长)以及它们的毒性窗口。此外, 优先顺序将涉及化合物的物理化学性质、化学处理能力和结合效率 使用最先进的筛查后分诊方法。进一步的验证测试将采用工程设计的“测试” 试管细胞“酿酒酵母菌株，其靶标在质膜上表达为 只有它的底物的运输者。优先命中的化学类型的结构-活性关系为 很早就建立了。Hit-to-Lead药物化学将在优先命中进行，重点放在低宿主上 支持化合物进入体内的细胞毒性和物理化学性质 药代动力学和药效实验。该项目将为以下项目提供高质量的先导化合物 进一步发展成为一种抗真菌增强剂，并有可能作为一种毒性修饰的单一试剂。