Non-cyp51A-mutation Mediated Triazole Resistance in Aspergillus fumigatus

非 cyp51A 突变介导的烟曲霉三唑耐药性

• 批准号: 10358515
• 负责人: Jarrod R. Fortwendel
• 金额: $ 65.83万
• 依托单位: UNIVERSITY OF TENNESSEE HEALTH SCI CTR
• 依托单位国家: 美国
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-03-01 至 2025-02-28
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10358515
• 关键词: Address; Affect; Alleles; Anabolism; Antifungal Agents; Antifungal Therapy; Aspergillosis; Aspergillus; Aspergillus fumigatus; Automobile Driving; CRISPR/Cas technology; Clinical; Collection; Complex; Coupled; DNA Sequence Alteration; Data; Diagnosis; Diffusion; Disease; Drug Transport; Ensure; Ergosterol; Evolution; Exhibits; Fungal Drug Resistance; Gene Expression Profile; Gene Expression Profiling; Genes; Genetic; Genome; Genomics; Goals; Hydroxymethylglutaryl-CoA reductase; Immunocompromised Host; In Vitro; Individual; Infection; Knowledge; Laboratories; Mediating; Methods; Molds; Molecular; Molecular Analysis; Molecular Genetics; Morbidity - disease rate; Mutation; Outcome; Pathway interactions; Play; Predisposition; Proteins; Regulation; Research; Resistance; Resistance development; Resistance profile; Risk; Role; Sequence Analysis; Sterol Biosynthesis Pathway; Sterols; System; Techniques; Testing; Therapeutic; Transcriptional Activation; Translating; Treatment Failure; Triazoles; Voriconazole; Work; base; clinical predictors; clinically relevant; differential expression; effective therapy; enzyme biosynthesis; experimental study; genetic analysis; genetic manipulation; genome analysis; human pathogen; improved; inhibitor; innovation; insight; mortality; mutant; novel; novel strategies; overexpression; patient population; prevent; public health relevance; resistance mechanism; resistance mutation; resistant Aspergillus; stem; treatment choice; whole genome

A critical barrier to overcoming triazole resistance in Aspergillus fumigatus is the significant lack of understanding of its genetic and molecular basis. We have shown that the known mechanisms of resistance do not fully explain resistance observed among most clinical isolates. Our long-term goal is to improve antifungal therapy and ensure the sustained clinical utility of the triazole class for treatment of infections caused by Aspergillus species. Our central hypothesis is that non-cyp51A-mutation mediated mechanisms are essential to triazole resistance in clinical isolates of A. fumigatus and involve complex genetic changes altering 1) sterol biosynthesis and its transcriptional activation, 2) triazole transport and its transcriptional activation, and 3) as yet unknown mechanisms. Our current objective is to address critical knowledge gaps by identifying the genetic and molecular determinants of non-cyp51A-mutation mediated resistance. Our preliminary data suggest that while mutations in cyp51A among triazole resistant clinical isolates are common, their overall contribution to resistance is minimal. We have observed mutations, unique to resistant isolates in our collection, in genes encoding sterol sensing proteins, regulators of sterol biosynthesis, and sterol biosynthesis enzymes. We have also observed clinical isolates that overexpress not only cyp51A, but most genes of the ergosterol biosynthesis pathway, suggesting its constitutive activation. We have observed several potential transporters that are up- regulated among triazole resistant isolates in our collection, suggesting a role for triazole efflux and resistance by these transporters. We have also shown that clinical isolates of A. fumigatus take up triazole antifungals via facilitated diffusion and we believe that altered triazole import may represent an important mechanism of resistance. To accomplish our objective we will undertake experiments that will lead to an understanding of what genetic and molecular determinants influence triazole susceptibility through altered sterol biosynthesis or its transcriptional activation (Aim 1) and triazole transport and its regulation (Aim 2). In Aim 3, we will also utilize an unbiased whole genome comparisons, coupled with in vitro evolution experiments, to identify completely novel mechanisms of resistance in clinical isolates. Our approach is innovative as we will use the latest genetic and genomic techniques to study and discover novel non-cyp51A-mutation mediated mechanisms of triazole resistance that are operative in a U.S.-based collection of triazole resistant clinical isolates. The proposed research is significant as it represents a comprehensive analysis of the molecular and genetic basis of non- cyp51A-mutation mediated triazole resistance in A. fumigatus and will provide novel insights into ways in which triazole activity can be improved against this important human pathogen.

克服烟曲霉对三唑耐药性的一个关键障碍是缺乏