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Antibiotic tolerance: membraneless organelles and autolysin regulation

抗生素耐受：无膜细胞器和自溶素调节

基本信息

批准号：
10618131
负责人：
Elaine I Tuomanen
金额：
$ 45.5万
依托单位：
ST. JUDE CHILDREN'S RESEARCH HOSPITAL
依托单位国家：
美国
项目类别：
财政年份：
2022
资助国家：
美国
起止时间：
2022-05-05 至 2027-04-30
项目状态：
未结题

来源：
https://reporter.nih.gov/project-details/10618131
关键词：
Affect Algorithms Alleles Amino Acid Sequence Animal Model Antibiotic Resistance Antibiotics Autolysin Autolysis Bacteria Bacterial Physiology Bacterial Proteins Binding Biochemical Biological Biological Assay Brain Cell Nucleolus Cell Wall Cessation of life Cleaved cell Clinical Communicable Diseases Compensation Complex Cytolysis Data Dissection Doctor of Philosophy Down-Regulation Engineering Enzymes Eukaryota Excision Failure Family Genetic Genome Goals Grant Growth Host Defense Immune Immunocompromised Host Individual Infection Laboratories Lytic Membrane Meningitis Methods Microscopic Modeling Molecular Multiprotein Complexes Mus Mutation Nyssa Organelles Pathway interactions Patients Penicillins Phase Phenotype Physical condensation Physiological Pneumonia Process Production Property Proteins Regulation Relapse Role Sepsis South Africa Streptococcus Streptococcus pneumoniae Study models Sum Surface System Testing Time Tissues Treatment Failure Variant antibiotic tolerance antimicrobial peptide bactericide biological adaptation to stress capsule cathelicidin antimicrobial peptide clinical phenotype combat genome analysis in vivo insight model organism multidrug tolerance mutant novel pathogen pressure response skills spatiotemporal suicidal tool

项目摘要

Antibiotic resistance and tolerance are a major increasing threat to treating infectious diseases. Streptococcus pneumoniae, the leading cause of pneumonia, sepsis, and meningitis worldwide, is a model organism for understanding antibiotic-induced autolysis and failure of therapy due to antibiotic tolerance: a phenotype when bacteria stop growing but are not killed. The main pneumococcal autolysin, LytA, drives autolysis but its mode of downregulation during tolerance is unknown. We have discovered a new LytA activity: capsule shedding and through its analysis have, for the first time, discovered candidates for regulators of LytA that also could explain the modulation of penicillin responses that lead to tolerance and treatment failure. Using the pneumococcus as a model, our lab has revealed that, for capsule shedding, LytA is activated to cleave cell wall without lysis in response to antimicrobial peptides, typified but not limited to LL- 37. Rather, LytA removes surface attached capsule in a protective response to avoid LL-37. We have identified 3 loci that regulate these activities of LytA. Mutation of these LytA modulating (Lym) loci recapitulates the penicillin tolerance phenotype of clinical isolates: production of bioactive LytA, but a failure to trigger autolysis after penicillin treatment. Our discovery provides tools to make important inroads into defining the mechanisms governing antibiotic lytic responses (the first mechanistic discovery of how LytA is controlled). From analysis of genomes of streptococcal pathogens in general, it is apparent that lym loci are widespread and have alleles that cluster with distinct penicillin tolerant phenotypes. New insights into autolysin and penicillin responses are needed to advance both the fields of bacterial physiology and infectious diseases. We propose in Aim 1 to take a combined biochemical, genetic, and microscopic approach to analyze the roles of the Lym proteins and lym loci on LytA regulation. In aim 2, we will exploit our new discovery that 3 Lym proteins are the first bacterial proteins shown to form biomolecular condensates and initiate phase separation. This property is widely used in eukaryotes to regulate complex spatiotemporal multi-protein processes and is thus especially well-suited as a highly novel mechanism to underpin LytA regulation by 3 Lyms. In Aim 3, we will examine lym alleles in tolerant clinical isolates of pneumococcus. These isolates are derived from patients dying of meningitis due to treatment failure that is recapitulated in the animal model of meningitis. We will define Lyms as a cause of failure of potent bactericidal action of antibiotics due to tolerance.

抗生素耐药性和耐受性是治疗感染性疾病日益严重的主要威胁