Evolved Heterogeneity Contributes to Chronic Fungal Lung Infections

进化的异质性导致慢性肺部真菌感染

• 批准号: 9381399
• 负责人: DEBORAH A HOGAN
• 金额: $ 41.87万
• 依托单位: DARTMOUTH COLLEGE
• 依托单位国家: 美国
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-07-19 至 2021-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9381399
• 关键词: Address; Alleles; Amphotericin B; Antifungal Agents; Antifungal Therapy; Bacteria; Bacterial Infections; C-terminal; Candida; Candida albicans; Caspofungin; Cells; Chronic; Clinical; Code; Collection; Complex; Cystic Fibrosis; Data; Development; Diagnosis; Disease Outbreaks; Drug resistance; Environment; Evolution; Fluconazole; Fluconazole resistance; Fungal Drug Resistance; Genes; Genetic; Genome; Genomics; Glycolysis; Growth; Haploidy; Heterogeneity; Human; Infection; Infection prevention; Lead; Lung; Maintenance; Measures; Metabolic; Microbial Biofilms; Minimum Inhibitory Concentration measurement; Multi-Drug Resistance; Mutation; Mycoses; Nutritional; Partner in relationship; Pharmaceutical Preparations; Phenotype; Population; Population Density; Population Heterogeneity; Predisposition; Pulmonary Fibrosis; Reporting; Resistance; Resistance development; Resort; Sampling; Structure; System; Testing; Time; Treatment Failure; Variant; Yeasts; combat; differential expression; effective therapy; fitness; genome sequencing; in vivo; metabolic phenotype; multi-drug resistant pathogen; pathogen; pressure; resilience; resistance factors; resistance mechanism; transcription factor; tumor; whole genome

Chronic fungal infections are often recalcitrant to treatment. The recalcitrance of chronic infections is not well understood, but likely involves multiple factors including biofilm formation, and slow growth. In addition, diverse studies in different systems from bacterial infections to human tumors, found that populations can have heterogeneous drug susceptibilities even before treatment is initiated, leading to treatment failures. Heterogeneity within populations of fungal pathogens has not been well studied. We have identified chronic high burden C. lusitaniae lung infections in three unrelated subjects with cystic fibrosis (CF). C. lusitaniae has been documented in CF lung infections previously, but infections dominated by C. lusitaniae are not widely reported. In all three subjects, C. lusitaniae isolates within each population showed high variance in antifungal sensitivity, measured as the minimum inhibitory concentration (MIC), with some isolates stably resistant. We characterized the isolates from one subject further and discovered, through whole genome sequencing, that variable MICs correlated with heterogeneity in alleles of MRR1, a gene associated with clinical drug resistance in other Candida spp. exposed to drugs. Variation in MRR1 alleles within a single population was surprising as this subject had not been prescribed antifungals in the preceding year. Because of the ease of manipulation of C. lusitaniae, a haploid, genetically tractable, mating competent, yeast, we propose to leverage these isolate collections to study the basis for drug resistance, factors that promote selection for increased drug resistance, and factors that promote heterogeneous population structures in the lung. In Aim 1, we will test the hypothesis that substitutions in the Mrr1 central regulatory domain and Mrr1 C-terminal truncations lead to increased activity (1.1), that common and distinct genes are controlled by different classes of Mrr1 variants (1.2), and that differentially expressed Mrr1-regulated genes contribute to fluconazole resistance (1.3). In Aim 2, we will test the hypothesis that specific SNPs impact metabolic diversity (2.1), high Mrr1 activity promotes fitness in isolates with high rates of glycolysis (2.2), and that metabolic diversification promotes heterogeneity in drug resistance in nutritionally complex environments (2.3). Because of the propensity of C. lusitaniae to develop resistance to potent drugs like amphotericin B, often the antifungal of last resort, and the close relationship between C. lusitaniae and a recent multi-drug resistant fungal pathogen of concern, Candida auris, these studies are highly relevant to discovering ways to better understand the composition of chronic infections, to limit the development of antifungal resistance, and to combat resistant isolates once they develop.

慢性真菌感染通常是治疗的顽固性。慢性感染的顽固性不好 理解，但可能涉及多种因素，包括生物膜形成和生长缓慢。另外，多样化 从细菌感染到人类肿瘤的不同系统的研究，发现种群可以拥有 甚至在开始治疗之前，都会导致治疗失败。 真菌病原体种群中的异质性尚未得到很好的研究。我们已经确定了慢性 三名无关的患有囊性纤维化（CF）的无关受试者中的高负荷肺癌肺部感染。 C. lusitaniae拥有 以前是在CF肺部感染中记录的，但卢西塔尼亚的感染并不广泛 报告。在所有三个受试者中，每个种群中的卢西塔尼亚分离株均显示出抗真菌的差异很大 灵敏度，以最小抑制浓度（MIC）测量，一些分离株稳定抗性。我们 进一步表征了来自一个主题的分离株，并通过整个基因组测序发现 可变麦克风与MRR1等位基因的异质性相关，MRR1的等位基因与临床耐药性相关的基因 在其他念珠菌中。暴露于药物。单个人群中MRR1等位基因的变化令人惊讶，因为 在上一年，该主题尚未被处方抗真菌。因为很容易操纵 C. lusitaniae，一种单倍体，遗传性的，交配能力，酵母，我们建议利用这些分离株 收集以研究耐药性的基础，促进选择耐药性的选择的因素， 以及促进肺部异质种群结构的因素。在AIM 1中，我们将检验假设 在MRR1中央调节结构域和MRR1 C末端截断中取代导致增加 活动（1.1），常见和不同的基因由不同类别的MRR1变体（1.2）控制，并且 差异表达的MRR1调节基因有助于氟康唑耐药性（1.3）。在AIM 2中，我们将测试 特定SNP会影响代谢多样性的假设（2.1），高MRR1活性促进了适应性 糖酵解率高的分离株（2.2），而代谢多样性促进了药物的异质性 营养复杂环境中的抗性（2.3）。因为卢西塔尼亚念珠菌的倾向 对有效药物（例如两性霉素B）的抗性，通常是最后一度的抗真菌和密切关系 在Lusitaniae和最近的多药耐药真菌病原体之间，Auris，这些 研究与发现更好地了解慢性感染的组成的方法高度相关 限制抗真菌性抗性的发展，并在产生抗性分离株后打击。