Inhibiting sequential biosynthetic steps of a fungal-specific organelle

抑制真菌特异性细胞器的连续生物合成步骤

• 批准号: 10165488
• 负责人: JULIA R KOEHLER
• 金额: $ 47.38万
• 依托单位: BOSTON CHILDREN'S HOSPITAL
• 依托单位国家: 美国
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-05-15 至 2024-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10165488
• 关键词: Affect; Affinity; Amphotericin; Anabolism; Antibiotics; Antifungal Agents; Biochemistry; Biological; Biological Assay; Candida; Candida albicans; Candida auris; Candidiasis; Cell Wall; Cell physiology; Cells; Centers for Disease Control and Prevention (U.S.); Cessation of life; Chemicals; Combined Antibiotics; Complex; Cotrimoxazole; Defect; Development; Disease; Drug Targeting; Elements; Equilibrium; Funding; Genetic; Glucans; Glucose; Glucosyltransferase; Goals; Growth; Homeostasis; Homologous Gene; Human; Hypersensitivity; Immunocompromised Host; Individual; Infection; Inorganic Phosphate Transporter; Lead; Libraries; Link; Micafungin; Mucorales; Mycoses; Nucleotides; Nutritional; Organelles; Outcome; Oxidative Stress; Patients; Pharmaceutical Chemistry; Pharmaceutical Preparations; Pharmacology; Phenotype; Polymers; Process; Production; Resistance; Signal Transduction; Sirolimus; Specificity; Stress; Sulfamethoxazole; System; Tetrahydrofolates; Toxic effect; Trimethoprim; Trimethoprim-Sulfamethoxazole; United States; Uridine Diphosphate; Validation; Virulence; Work; antimicrobial; attributable mortality; base; chemical genetics; clinical care; design; drug development; drug discovery; emerging pathogen; experience; fitness; fungus; glucan synthase; high throughput screening; inhibitor/antagonist; inorganic phosphate; metabolomics; microbial; novel; novel therapeutics; optimal treatments; pathogenic fungus; response; screening; sugar nucleotide

PROJECT SUMMARY/ABSTRACT Candida albicans is the most frequently isolated fungus causing invasive disease in the United States. These infections are dreaded complications of serious illnesses, especially in hospitalized or immunocompromised patients. C. albicans infections are challenging to eradicate, and are still estimated to lead to death in 20% of the affected patients. Currently only 3 classes of antifungal drugs are available to treat invasive fungal infections. Antifungal drug development is difficult because of the similarity between fungal and human cells, which leads to unacceptable toxicity of many compounds that damage or kill fungi. Developing antifungal agents whose targets are absent in human cells would circumvent this difficulty. Increasing potency of antifungal drugs could also lead to better outcomes. A paradigm for increased antimicrobial potency is the important combination antibiotic Cotrimoxazole, whose two components target sequential steps in the biosynthesis of tetrahydrofolate. The goal of this proposal is to find compounds that can be developed into specific inhibitors of two cellular processes unique to fungi, whose combination could give rise to a more potent antifungal agent. Two fungal cellular processes that are fundamentally different or absent in humans are phosphate homeostasis and cell wall construction. We previously found that the major C. albicans high-affinity phosphate transporter Pho84 is required for normal nutritional (Target of Rapamycin-) signaling, cell wall stress- and oxidative stress resistance, hyphal growth and virulence. Since humans manage their phosphate balance completely differently from fungi, blocking Pho84 is not predicted to impact human cellular functions. Pho84 is highly conserved across the fungal kingdom, including in emerging pathogens like Candida auris. Cells that lack Pho84 contain diminished concentrations of nucleotides, whose production requires ample intracellular phosphate supplies, and of their downstream metabolites, nucleotide sugars. Nucleotide sugars are precursors for biosynthesis of the major cell wall polymers. We propose to take advantage of this defect to sequentially perturb major steps in cell wall biosynthesis by combining inhibition of Pho84 with inhibition of glucan biosynthesis. To do this, we established a novel high-throughput assay system to detect specific inhibitors of these fungal targets. We will prioritize hit compounds according to their biological effects in virulence-associated or essential cellular processes, and according to their chemical features. This work will lay the ground to apply the paradigm of stepwise inhibition of a critical biosynthetic process to antifungal drug development. The proposal is intended to select screen hits that meet defined biological and medicinal chemistry criteria for further development.

项目摘要/摘要 白色念珠菌是美国最常见的真菌，在美国引起侵入性疾病。 这些感染是严重疾病的可怕并发症，尤其是住院或 免疫功能低下的患者。白色念珠菌感染具有挑战性，仍在估计 导致20％的患者死亡。目前只有3类抗真菌药物可用 治疗侵入性真菌感染。抗真菌药物开发很困难，因为 真菌和人类细胞，这会导致许多损害或杀死真菌的化合物的不可接受的毒性。 开发抗真菌剂的靶标在人类细胞中不存在靶标会规避这一困难。 抗真菌药物的效力的提高也可能导致更好的预后。增加的范式 抗微生物效力是重要组合抗生素共瑞唑唑，其两个成分靶向 四氢叶酸的生物合成的顺序步骤。 该提案的目的是找到可以发展为两个的特定抑制剂的化合物 真菌独有的细胞过程，其组合可能会导致更有效的抗真菌剂。 在人类中根本不同或不存在的两个真菌细胞过程是磷酸盐 体内平衡和细胞壁结构。我们以前发现白色念珠菌高亲和力 磷酸转运蛋白PHO84是正常营养（雷帕霉素）信号传导所必需的 应激和氧化应激性，菌丝生长和毒力。自从人类管理他们的 磷酸盐平衡与真菌完全不同，预计阻止PHO84不会影响人类 细胞功能。 Pho84在真菌王国中高度保守，包括在新兴病原体中 像念珠菌一样。缺乏PHO84的细胞含有浓度降低的核苷酸，它们的核苷酸的浓度降低 生产需要充足的细胞内磷酸盐供应及其下游代谢产物， 核苷酸糖。核苷酸糖是主要细胞壁聚合物生物合成的前体。我们 提议利用这种缺陷来依次扰动细胞壁生物合成的主要步骤 将PHO84的抑制作用与葡萄糖生物合成的抑制作用。为此，我们建立了一本小说 高通量测定系统以检测这些真菌靶标的特定抑制剂。我们将优先级命中 根据其在毒力相关或必需的细胞过程中的生物学作用，以及 根据他们的化学特征。这项工作将奠定地面以应用逐步的范式 抑制抗真菌药物开发的关键生物合成过程。该提议旨在 符合定义的生物学和药物化学标准以进一步发展的精选屏幕命中。