Antibiotic tolerance: membraneless organelles and autolysin regulation

抗生素耐药性和耐受性是治疗感染性疾病的主要威胁 疾病。肺炎链球菌，肺炎、败血症和脑膜炎的主要原因 是了解抗生素诱导的自溶和失败的模式生物 抗生素耐药引起的治疗：细菌停止生长但没有被杀死的一种表型。 主要的肺炎球菌自溶素LytA驱动自溶，但其下调模式在 耐受性是未知的。我们发现了一种新的LytA活动：胶囊脱落并通过其 分析首次发现LytA监管机构的候选人也可能 解释导致耐受和治疗失败的青霉素反应的调节。vbl.使用 以肺炎球菌为模型，我们实验室已经揭示，对于包膜脱落，LytA是被激活的 不裂解细胞壁对抗菌肽的反应，典型但不限于LL- 37.相反，LytA在保护性反应中移除了表面附着的胶囊，以避免LL-37。我们 已经确定了3个调节LytA这些活性的基因座。这些LytA调节因子的突变 (Lym)基因座概括了临床分离株的青霉素耐药表型：产生 生物活性LytA，但青霉素治疗后未能触发自溶。 我们的发现提供了在定义机制方面取得重要进展的工具 管理抗生素裂解反应(LytA是如何被控制的第一个机械发现)。 从对链球菌病原体基因组的总体分析来看，很明显，Lym基因座是 分布广泛，并具有与青霉素耐药表型不同的等位基因。新见解 转化为自溶素和青霉素的反应需要促进细菌的这两个领域 生理学和传染病。 我们在目标1中建议采取生化、遗传和微观相结合的方法。 分析LYM蛋白和LYM基因座在LytA调控中的作用。在目标2中，我们将利用 我们的新发现：3个Lym蛋白是第一个形成生物分子的细菌蛋白 冷凝物和启动相分离。这一特性在真核生物中被广泛用于调节 复杂的时空多蛋白质过程，因此特别适合作为高度 3个LYM支持LytA调控的新机制。在目标3中，我们将检查LYM等位基因 耐药肺炎球菌临床分离株。这些分离株来自于死于 由于治疗失败而导致的脑膜炎，在脑膜炎的动物模型中反复出现。我们会 将LYMS定义为由于耐受性而导致抗生素有效杀菌作用失败的原因。

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.