Variations in a master regulator affects Clostridioides difficile physiology and virulence

主调节因子的变化影响艰难梭菌的生理学和毒力

• 批准号: 10508951
• 负责人: REVATHI GOVIND
• 金额: $ 22.73万
• 依托单位: KANSAS STATE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-06-14 至 2024-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10508951
• 关键词: Affect; Affinity; Alleles; Amino Acids; Antibiotics; Applications Grants; Asparagine; Bacteria; Binding; Binding Proteins; Biological Assay; Branched-Chain Amino Acids; Cells; Centers for Disease Control and Prevention (U.S.); Clinical; Clostridium difficile; Colon; DNA; DNA Binding; Data; Databases; Development; Disease; Disease Outbreaks; Drops; Environmental Risk Factor; Epidemic; Gene Expression; Genes; Genetic Transcription; Genome; Growth; Guanosine Triphosphate; Hamsters; In Vitro; Individual; Infection; Intervention; Isoleucine; Knowledge; Leucine; Ligand Binding; Ligands; Link; Location; Mediating; Metabolic Pathway; Microbial Physiology; Modeling; Mutation; Nutrient; Nutritional status; Pathogenesis; Pathogenicity; Phase; Physiology; Point Mutation; Positioning Attribute; Production; Proteins; Pseudomembranous Colitis; Radiolabeled; Regulation; Regulon; Reproduction spores; Research; Risk Factors; Testing; Tissues; Toxin; Transcript; Tyrosine; Valine; Variant; Virulence; Virulence Factors; Virulent; alpha Toxin; antibiotic-associated diarrhea; design; detection of nutrient; dimer; experimental study; gene regulatory network; gut microbiota; in vivo; nutrient deprivation; pathogen; pathogenic bacteria; promoter; response; transcriptome sequencing

PROJECT SUMMARY Clostridioides difficile is an important nosocomial pathogen that has been classified as an “urgent threat” by CDC. Antibiotic use is the primary risk factor for the development of C. difficile-associated disease because it disrupts healthy protective gut flora and enables C. difficile to colonize the colon. C. difficile damage host tissue by secreting toxins and disseminates by forming spores. The toxins encoding genes, tcdA, and tcdB are part of a pathogenicity locus and are positively regulated by tcdR. Nutrient availability and other environmental factors greatly influence toxin production in C. difficile. CodY, a protein found in many Gram-positive bacterial pathogens, is an important factor that regulates major metabolic pathways and virulence gene expression in response to nutrient availability. In C. difficile, CodY senses the nutritional status of the cell by binding to ligands, GTP, and branched-chain amino acids (Isoleucine, Leucine, and Valine-ILV), and this active CodY then represses toxin genes transcription by binding to the promoter of tcdR and repressing its transcription. We have identified that the codY gene in an epidemic C. difficile strain (R20291) carries a point mutation that changes its Tyrosine residue at the 146th position to an Asparagine (codYY146N). Following this observation, our search in the database leads us to the codYV58A allele in more than 170 different C. difficile strains of different origins. Similar to Y146 (at the dimer interface), V58 is located (ILV binding domain) at a crucial position in CodY and can influence its activity. Preliminary data indicated that CodYY146N and CodYV58A differ from wild-type CodY in their function and activity. Any change in the activity of a master regulator can alter the gene regulatory networks under its control. Proposed studies in this exploratory grant application will identify the readjusted gene regulatory networks in C. difficile because of the production CodYV58A or CodYY146N and will evaluate their effect in C. difficile physiology and pathogenesis.

项目摘要 梭状芽胞杆菌艰难梭菌是一种重要的医院病原体，已被归类为一种 CDC的“紧急威胁”。抗生素使用是开发C的主要危险因素。 与艰难的疾病相关，因为它破坏了健康的受保护的肠道菌群并启用C。 艰难的结肠定居。艰难梭菌通过分泌毒素和 通过形成孢子来传播。编码基因，TCDA和TCDB的毒素是A的一部分 致病基因座，并由TCDR阳性调节。营养可用性和其他 环境因素极大地影响了艰难梭菌的毒素产生。科迪，一种在 许多革兰氏阳性细菌病原体是调节主要代谢的重要因素 途径和病毒基因表达响应养分的可用性。在艰难梭菌中，科迪 通过与配体，GTP和分支链氨基结合来感知细胞的营养状况 酸（异亮氨酸，亮氨酸和Valine-ilv），然后这种活性的Cody再现毒素基因 通过与TCDR的启动子结合并反映其转录来转录。我们有 鉴定出流行性艰难梭菌菌株（R20291）中的Cody基因带有点突变 这将其在第146位位置的酪氨酸居住区更改为天冬酰胺（Codyy146n）。下列的 这个观察结果，我们在数据库中的搜索使我们进入了170多个的Codyv58a等位基因 不同起源的不同艰难梭菌菌株。类似于Y146（在二聚体接口），V58是 位于Cody至关重要的位置（ILV结合结构域），可以影响其活性。 初步数据表明，Codyy146n和Codyv58a与野生型Cody不同 功能和活动。主调节器的活动的任何变化都可以改变基因 监管网络在其控制之下。在此探索性赠款申请中提出的研究将 确定艰难梭菌中的重新调节基因调节网络，因为 Codyv58a或Codyy146n，将评估它们在艰难梭菌生理和发病机理中的作用。