Macrophage Immunosuppression by Quorum-Induced Streptococcus pyogenes

摘要 化脓性链球菌群体诱导的巨噬细胞免疫抑制作用 人类限制性致病共生菌化脓性链球菌（A组链球菌，GAS）使用 Rgg 2/Rgg 3 QS系统修饰细菌表面，允许生物膜形成和溶菌酶的协调 阻力初步研究结果表明，天然免疫细胞对GAS的反应发生了实质性改变， 细菌的QS状态。已发表的和初步的数据表明，巨噬细胞活化，刺激 通过多种激动剂并通过细胞因子产生和NF κ B B活性评估， 与QS-ON GAS相互作用，但不与QS-OFF细菌相互作用。巨噬细胞活力和细菌粘附 在QS活性状态之间存在差异，但TNF α、IL-6、INF β水平和NF β B报告基因在QS活性状态之间存在差异。 抑制需要活细菌和巨噬细胞之间的接触。一 GAS基因组中的QS调节的生物合成基因簇（BGC），编码几种假定的酶， 也是巨噬细胞调节所必需的。巨噬细胞的新获得性转录组学分析（RNA-Seq） 感染QS-ON和QS-OFF GAS表明感染之间基因表达模式明显不同 类型QS-OFF感染诱导巨噬细胞具有经典活化（M1样）的特征， 而QS-ON感染产生的遗传特征与交替激活（M2样） 巨噬细胞，其中氧化磷酸化和脂肪酸β-氧化的代谢途径被诱导。 我们提出了一个模型，即与巨噬细胞接触后，QS-ON GAS产生BGC衍生因子， 抑制炎症反应。治疗后QS-ON GAS的抑制能力消失 特定的QS抑制剂这些观察结果表明，干扰细菌的协作能力， 通过QS可以作为一种策略，以抵消微生物的努力，操纵宿主的防御。本申请 旨在实现三个主要目标：1）确定BGC和 生物合成中间体; 2）鉴定巨噬细胞靶标和NF κ B B抑制机制;和3）评估 对免疫细胞活性的生理影响以及GAS在体内和人外植体中提供的优势 组织模型

Abstract Macrophage Immunosuppression by Quorum-Induced Streptococcus pyogenes The human-restricted pathosymbiont Streptococcus pyogenes (Group A Streptococcus, GAS) uses the Rgg2/Rgg3 QS system to modify the bacterial surface, allowing coordination of biofilm formation and lysozyme resistance. Preliminary findings demonstrate that innate immune cell responses to GAS are substantially altered by the QS status of the bacteria. Published and preliminary data show that macrophage activation, stimulated by multiple agonists and assessed by cytokine production and NFB activity, was substantially suppressed upon interaction with QS-ON GAS but not QS-OFF bacteria. Neither macrophage viability nor bacterial adherence were seen as different between QS activity states, yet TNF, IL-6, INF levels and an NFB reporter were drastically lower when QS was ON. Suppression required contact between viable bacteria and macrophages. A QS-regulated biosynthetic gene cluster (BGC) in the GAS genome, encoding several putative enzymes, was also required for macrophage modulation. Newly acquired transcriptomic analysis (RNA-Seq) of macrophages infected with QS-ON and QS-OFF GAS indicate clear divergence in gene expression patterns between infection types. QS-OFF infections induce macrophage characteristics with signatures of classic activation (M1-like), whereas QS-ON infections produced genetic signatures consistent with alternatively activated (M2-like) macrophages, where metabolic pathways of oxidative phosphorylation and fatty acid beta-oxidation are induced. We propose a model that upon contact with macrophages, QS-ON GAS produce a BGC-derived factor capable of suppressing inflammatory responses. The suppressive capability of QS-ON GAS is abolished after treatment with a specific QS inhibitor. These observations suggest that interfering with the ability of bacteria to collaborate via QS can serve as a strategy to counteract microbial efforts to manipulate host defenses. This application seeks to accomplish three primary objectives: 1) identify the QS-regulated factor generated by the BGC and the biosynthetic intermediates; 2) identify the macrophage target and mechanism of NFB inhibition; and 3) evaluate the physiological impact on immune cell activity and the advantage provided to GAS in vivo and in human explant tissue models.