Macrophage Immunosuppression by Quorum-Induced Streptococcus pyogenes

摘要 群体诱导的化脓性链球菌对巨噬细胞的免疫抑制作用 人类限制的致病共生菌化脓性链球菌(A组)使用 Rgg2/Rgg3 QS系统修饰细菌表面，允许生物膜形成和溶菌酶的协调 抵抗。初步研究结果表明，天然免疫细胞对气体的反应发生了很大的变化。 由细菌的QS状态决定。已发表的和初步的数据显示，巨噬细胞激活，刺激 由多种激动剂并通过细胞因子产生和核因子B活性进行评估，基本上抑制了 与QS-On气体相互作用，但不与QS-Off细菌相互作用。无论是巨噬细胞活性还是细菌黏附 被认为在QS活动状态之间是不同的，而肿瘤坏死因子、IL-6、干扰素水平和一个NFB报告是 在启用QS时显著降低。抑制需要活细菌和巨噬细胞之间的接触。一个 GAS基因组中受QS调控的生物合成基因簇(BGC)编码几种可能的酶。 巨噬细胞的调节也是必需的。新获得的巨噬细胞转录分析(RNA-Seq) 感染QS-ON和QS-OFF气体表明感染之间的基因表达模式存在明显差异 类型。QS-Off感染诱导具有典型激活特征的巨噬细胞特征(M1样)， 而QS-ON感染产生的基因特征与交替激活的(类M2)一致 巨噬细胞，在那里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，当与巨噬细胞接触时，qs-on气体产生一种bgc衍生因子，能够 抑制炎症反应。治疗后QS-对气体的抑制能力消失 使用一种特定的QS抑制剂。这些观察表明，干扰细菌的合作能力 Via QS可以作为一种策略来对抗微生物操纵宿主防御的努力。此应用程序 寻求实现三个主要目标：1)确定由BGC和 生物合成中间体；2)确定抑制核因子B的巨噬细胞靶点和机制；3)评估 GAS对免疫细胞活性的生理影响及其在体内和人体外植体中的优势 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.