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.

慢性真菌感染往往难以治疗。慢性感染的预防效果不好 可以理解，但可能涉及多种因素，包括生物膜形成和缓慢生长。此外，多样 从细菌感染到人类肿瘤的不同系统的研究发现， 即使在治疗开始之前，也存在异质性药物敏感性，导致治疗失败。 真菌病原体种群内的异源性还没有得到很好的研究。我们发现了慢性的 高负荷C。在三个不相关的患有囊性纤维化（CF）的受试者中的lusitaniae肺部感染。C.卢西塔尼亚河 以前在CF肺部感染中有报道，但感染以C. lusitaniae并不广泛 报道在所有三个科目中，C.每个群体中的lusitaniae菌株在抗真菌药物中表现出很高的变异性， 敏感性，测量为最小抑菌浓度（MIC），一些分离株稳定耐药。我们 通过全基因组测序，进一步表征了来自一个受试者的分离物， 可变MIC与MRR 1等位基因的异质性相关，MRR 1是一种与临床耐药相关的基因 在其它念珠菌属中，接触毒品MRR 1等位基因在单个群体中的变异是令人惊讶的， 该受试者在前一年未被处方抗真菌药。由于易于操作， C. lusitaniae是一种单倍体、遗传上易处理、有交配能力酵母，我们建议利用这些分离物 收集研究耐药性的基础，促进选择增加耐药性的因素， 以及促进肺中异质群体结构的因素。在目标1中，我们将检验假设 Mrr 1中央调控结构域的取代和Mrr 1 C-末端截短导致 活性（1.1），共同和不同的基因由不同类型的Mrr 1变体控制（1.2）， 差异表达的Mrr 1调节基因导致氟康唑耐药（1.3）。在目标2中，我们将测试 特定SNP影响代谢多样性的假设（2.1），高Mrr 1活性促进了 糖酵解速率高的分离株（2.2），代谢多样化促进了药物的异质性， 在营养复杂的环境中的抵抗力（2.3）。由于C. lusitaniae发展 对强力药物如阿替西霉素B（通常是最后的抗真菌药物）的耐药性，以及 C. lusitaniae和最近关注的多重耐药真菌病原体，耳念珠菌，这些 这些研究与发现更好地了解慢性感染的组成， 限制抗真菌药物耐药性的发展，并在耐药菌株产生后立即与之斗争。