Investigating CovRS activation within skin microenvironments to drive heterogenicity of Streptococcus pyogenes gene expression

研究皮肤微环境中的 CovRS 激活以驱动化脓性链球菌基因表达的异质性

• 批准号: 10751462
• 负责人: Stephanie Corinne Guerra
• 金额: $ 4.77万
• 依托单位: EMORY UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-09-01 至 2026-08-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10751462
• 关键词: Acute Rheumatic Heart Disease; Antibiotics; Antibodies; Bacteria; Bacterial Infections; Biological Assay; Cell Culture Techniques; Cell Death; Cell Density; Cells; Cellular Structures; Cessation of life; Clustered Regularly Interspaced Short Palindromic Repeats; Confocal Microscopy; Cytolysis; Data; Diffusion; Disease; Disease Progression; Distant; Drug Targeting; Engineering; Enzyme-Linked Immunosorbent Assay; Exposure to; Gene Expression; Gene Expression Regulation; Genetic; Genetic Techniques; Genome; Goals; Health; Healthcare Systems; Heterogeneity; Human; Immune; Immune Evasion; Immune response; Immunity; Impairment; Impetigo; In Vitro; Infection; Infectious Skin Diseases; Inflammation; Inflammatory; Integration Host Factors; Knock-out; Life; Measures; Mediating; Metabolic; Microscopy; Modeling; Morbidity - disease rate; Mus; Necrotizing fasciitis; Operative Surgical Procedures; Pathogenesis; Pathology; Pathway interactions; Patients; Peptide Hydrolases; Peptides; Pharyngitis; Phosphorylation; Play; Population; Production; Regulation; Regulon; Reporter; Research; Resistance; Role; Series; Signal Transduction; Signaling Molecule; Skin; Streptococcus pyogenes; System; Testing; Toxic Shock Syndrome; Toxin; Transforming Growth Factor beta; United States; VDAC1 gene; Vaccines; Variant; Virulence; Virulence Factors; Virulent; Western Blotting; alternative treatment; antimicrobial peptide LL-37; cathelicidin antimicrobial peptide; chronic infection; erythrogenic toxin; experimental study; fighting; inflammatory milieu; insight; keratinocyte; keratinocyte differentiation; lactate dehydrogenase A; mortality; mutant; new therapeutic target; pathogen; response; single cell analysis; small molecule; three dimensional cell culture; treatment strategy

ABSTRACT Streptococcus pyogenes infections are a major burden to the healthcare system in the United States and globally. Most infections are mild and superficial, such as pharyngitis and impetigo. However, rapid disease progression may result in life-threatening invasive infections, such as necrotizing fasciitis and toxic shock syndrome. Furthermore, recovered patients often suffer post-infection chronic complications, including acute rheumatic heart disease. Altogether, S. pyogenes infections and post-infection complications result in more than 600,000 global deaths annually. Currently, there is no vaccine against S. pyogenes and high instances of morbidity and mortality highlight the urgent need for alternative treatment strategies. Unlike most pathogens, S. pyogenes thrives in inflammatory environments by expressing virulence factors that promote immune evasion, which is often associated with invasive infections. Approximately 15% of the genome, including most virulence factors, is regulated by a two-component system called CovRS (or CsrRS). CovRS detects the host peptide LL- 37, which functions as a potent signal for virulence factor regulation. However, it remains unclear how changes in LL-37 availability due to cell death alters CovRS regulation during the progression of an infection. Further, distinct toxins of S. pyogenes are expressed in CovRS “on/off” activity states, yet all are essential during infection. This indicates that sub-populations of genetically identical bacteria in different CovRS “on/off” states may release varying toxins during different stages of infection and within distinct microenvironments that collectively contribute to pathogenesis. I hypothesize that heterogenous CovRS regulation is controlled by variations of LL- 37 levels due to inflammatory cell death, allowing heterogenous toxin production necessary for S. pyogenes infections. I will test my hypothesis by 1) using genetics techniques within the host and pathogen to identify how inflammatory cell death impacts LL-37 release and CovRS regulons, and 2) using microscopy for single cell analysis to examine how local LL-37 concentration contributes to CovRS signaling in engineered S. pyogenes reporter strains. Collectively, these studies will provide insight into the mechanisms responsible for S. pyogenes- induced inflammation and identify novel drug targets that stall disease progression.

摘要