Dysregulation of the inflammatory response by Francisella tularensis

图拉热症是一种潜在的致命疾病，其病原体是图拉氏菌(Ft)，是为数不多的几种 可感染中性粒细胞(中性粒细胞，PMN)和巨噬细胞的细菌病原体。 值得注意的是，巨噬细胞和中性粒细胞似乎在图拉热症的发病机制中扮演着截然不同的角色， 巨噬细胞是细菌生长和传播的主要载体，中性粒细胞起核心作用 在宿主组织的破坏中。中性粒细胞是短暂的，与其他白细胞不同的是，中性粒细胞被预先编程为 释放到循环中24小时后发生细胞凋亡。对这一过程的严格的时空控制是 对于消除感染和消退炎症至关重要，因此PMN周转存在缺陷 例证了一种失控和无效的炎症反应，它促进了组织破坏和疾病。 与此相一致，我们发现Ft抑制了人中性粒细胞的凋亡，并显著延长了细胞 寿命，并证明这是通过影响内在和外在的凋亡途径实现的， 以及中性粒细胞转录组的变化，包括365个独特的显著差异表达 与细胞凋亡和细胞命运相关的基因。然而，电池寿命的延长只是部分原因 明白了。在此，我们提出了基于我们发现的中性粒细胞代谢的开创性研究。 重编程作为一种新的细胞凋亡抑制机制。我们建议的研究得到了广泛的支持 初步数据，具有很高的创新性，因为糖酵解和细胞器功能的综合操纵 以前没有文献记载在感染期间作为调节PMN寿命的机制。潜力 这些变化对细菌生长的影响及PMN代谢产物对巨噬细胞极化的影响 也将被确定。此外，我们最近发现细菌脂蛋白(Blp)是Ft的活性因子。 条件培养液(CM)，通过依赖于普通单细胞的机制延长PMN的寿命 人类TLR1(rs5743618，T1805G)的核苷酸多态(SNP)对严重程度有显著影响 败血症的致命性以及许多感染性和炎症性疾病的结果，包括但不是 仅限于肺结核、肾盂肾炎、动脉粥样硬化、关节炎、狼疮、结肠炎和癌症。澄清 本研究的第二个目标是BLP和TLR2/1诱导的细胞凋亡抑制机制(S)。我们的 实验设计还将利用针对HIF-1和TLR2、有丝分裂、糖酵解或 其他相关的信号中间体，以确定治疗干预点，预计 与许多影响退伍军人的疾病有关。我们的具体目标是：1)阐明机制和 中性粒细胞代谢重编程的功能后果。2)阐明BLP和BLP的发病机制 TLR2/1介导的细胞凋亡抑制及其治疗干预的潜力。

Tularemia is a potentially fatal disease and the causative agent, Francisella tularensis (Ft), is one of few bacterial pathogens that can infect both neutrophils (polymorphonuclear leukocytes, PMNs) and macrophages. Notably, macrophages and neutrophils appear to play distinctly different roles in tularemia pathogenesis, with macrophages acting as major vehicles for bacterial growth and dissemination, and PMNs playing a central role in host tissue destruction. Neutrophils are short lived, and unlike other leukocytes are preprogrammed to undergo apoptosis 24 h after release into the circulation. Tight spatial and temporal control of this process is critical for elimination of infection and resolution of inflammation, and for this reason defects in PMN turnover exemplify a dysregulated and ineffective inflammatory response that promotes tissue destruction and disease. In keeping with this, we discovered that Ft inhibits human neutrophil apoptosis and markedly prolongs cell lifespan, and demonstrated that this is achieved via effects on the intrinsic and extrinsic apoptosis pathways, as well as changes in the neutrophil transcriptome that include significant differential expression of 365 unique genes linked to apoptosis and cell fate. Nevertheless, how cell lifespan is prolonged is only partially understood. Herein, we propose groundbreaking studies based on our discovery of neutrophil metabolic reprogramming as a new mechanism for apoptosis inhibition. Our proposed studies are supported by extensive preliminary data, and are highly innovative, as integrated manipulation of glycolysis and organelle function has not been previously documented as a mechanism for regulation of PMN lifespan during infection. Potential effects of these changes on bacterial growth and the influence of PMN metabolites on macrophage polarization will also be determined. In addition, we recently identified bacterial lipoproteins (BLPs) as active factors in Ft conditioned medium (CM) that extend PMN lifespan via a mechanism that is dependent on a common single nucleotide polymorphism (SNP) in human TLR1 (rs5743618, T1805G) that significantly influences the severity and lethality of sepsis as well as the outcomes of many infectious and inflammatory diseases, including but not limited to tuberculosis, pyelonephritis, atherosclerosis, arthritis, lupus, colitis, and cancer. Elucidating the mechanism(s) of BLP and TLR2/1-driven apoptosis inhibition is a second objective of this study. Our experimental design will also utilize drugs that specifically target HIF-1 and TLR2, mitophagy, glycolysis or other relevant signaling intermediates to identify points for therapeutic intervention that are expected to be relevant to many diseases that affect Veterans. Our specific aims are: 1) To elucidate the mechanisms and functional consequences of neutrophil metabolic reprogramming. 2) To elucidate the mechanisms of BLP and TLR2/1-mediated apoptosis inhibition and potential for theraputic intervention.