Investigating a signaling molecule that cooperates with quorum sensing to induce biofilm formation in C. neoformans

研究与群体感应配合诱导新型隐球菌生物膜形成的信号分子

• 批准号: 10550504
• 负责人: Xiaorong Lin
• 金额: $ 22.65万
• 依托单位: UNIVERSITY OF GEORGIA
• 依托单位国家: 美国
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-11-25 至 2024-10-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10550504
• 关键词: Adhesions; Affect; Ascomycota; Bacterial Adhesins; Basidiomycota; Behavior; Candida; Cell surface; Clinical; Communicable Diseases; Communication; Communities; Complex; Coupling; Cryptococcus; Cryptococcus neoformans; Environment; Farnesol; Foundations; Future; Gene Deletion; Gene Expression; Gene Targeting; Genes; Genetic; Goals; HIV/AIDS; Homologous Gene; Human; Intercellular Communication Process; Investigation; Knowledge; Laboratories; Mass Spectrum Analysis; Mating Types; Meningoencephalitis; Microbe; Microbial Biofilms; Microbiology; Modeling; Mutagenesis; Mutation; Nature; Opportunistic Infections; Partner in relationship; Pathogenesis; Pathway interactions; Peptides; Persons; Pheromone; Prevalence; Process; Production; Proteins; Public Health; Regulation; Research; Role; Saccharomyces; Signal Induction; Signal Transduction; Signaling Molecule; Signaling Protein; Specificity; Structural Protein; Structure; System; T-DNA; Transcription Repressor; Work; congenic; fast protein liquid chromatography; fungus; gene discovery; in vivo; insight; intercellular communication; microbial community; mutant; novel; overexpression; pathogenic fungus; prevent; quorum sensing; response; transcription factor; transcriptome

ABSTRACT The objectives of this exploratory R21 proposal are to identify and characterize an intercellular communication signal that induces biofilm formation in cooperation with quorum sensing in the human fungal pathogen Cryptococcus neoformans. C. neoformans is a basidiomycetous fungus that causes cryptococcal meningoencephalitis (CME), one of the most fatal and common opportunistic infections affecting people with HIV/AIDS. Like many other infectious microbes, C. neoformans forms biofilm-like structures known as cryptococcoma in vivo. However, we know very little about the structural requirements for biofilms or their genetic regulation in this fungal pathogen, partly because Cryptococcus forms biofilms poorly under laboratory conditions, and partly because this basidiomycete does not carry homologues of any known biofilm-relevant proteins established in ascomycetes like Saccharomyces and Candida species. Here we found that disruption of a transcription repressor Ssn6 in a mating-type a strain, but not in the congenic mating-type α strain, leads to robust biofilm formation in C. neoformans, which provides an entry point for us to investigate genetic regulation of biofilm formation in this fungus. Interestingly, ssn6a biofilm colonies induce the nearby ssn6α colonies to also form biofilms and this process is independent of the mating pheromone. We discovered that the intercellular communication system which activates biofilm formation requires the quorum-sensing molecule Qsp1 and an unknown peptide-based signaling molecule. Here we propose to (1) identify the secreted biofilm signaling molecule and (2) elucidate the pathway involved in biofilm formation activated by this signaling molecule. The proposed work is expected to yield insights into this layered communication system that regulates such complex community behaviors in a clinically important fungal pathogen. We also expect to identify novel biofilm structural proteins like adhesins in Cryptococcus in this process, which will fill the critical gap in our knowledge about biofilm formation and regulation in basidiomycetes. The findings from this exploratory research will also provide a foundation for future investigation of the impact of biofilm regulation on cryptococcal pathogenesis.

抽象的 该探索性 R21 提案的目标是识别和表征细胞间通讯 与人类真菌病原体中的群体感应配合诱导生物膜形成的信号 新型隐球菌是一种担子菌真菌，可引起隐球菌。 脑膜脑炎 (CME) 是影响脑膜脑炎患者的最致命和最常见的机会性感染之一 与许多其他传染性微生物一样，新型隐球菌形成生物膜状结构，称为生物膜样结构。 然而，我们对生物膜或其结构要求知之甚少。 这种真菌病原体的遗传调控，部分原因是隐球菌在实验室下很难形成生物膜 条件，部分原因是这种担子菌不携带任何已知的生物膜相关的同源物 在子囊菌如酵母菌和念珠菌属中建立的蛋白质。 在这里，我们发现交配型 a 菌株中的转录阻遏蛋白 Ssn6 受到破坏，但在 同源交配型α菌株，导致新型隐球菌中强大的生物膜形成，这提供了一个入口 我们研究这种真菌生物膜形成的遗传调控。 菌落诱导附近的 ssn6α 菌落也形成生物膜，并且该过程与交配无关 我们发现激活生物膜形成的细胞间通讯系统。 需要群体感应分子 Qsp1 和未知的基于肽的信号分子。 提议（1）识别分泌的生物膜信号分子和（2）阐明参与生物膜的途径 由这种信号分子激活的形成预计将产生对这种分层的深入了解。 在临床上重要的真菌中调节如此复杂的群落行为的通信系统 我们还期望在此鉴定隐球菌中的新型生物膜结构蛋白，例如粘附素。 过程，这将填补我们关于生物膜形成和调节的知识的关键空白 这项探索性研究的结果也将为未来奠定基础。 研究生物膜调节对隐球菌发病机制的影响。