Olfactomedin 4 down-regulates neutrophil killing of Gram-positive and Gram-negat

慢性肉芽肿病（CGD）患者反复出现危及生命的细菌和真菌感染。嗅觉介导蛋白4（OLFM 4）是一种中性粒细胞颗粒蛋白，负调节宿主对细菌感染的防御。本研究的目的是在鼠X连锁CGD模型中评估Olfm 4缺失对宿主防御金黄色葡萄球菌和烟曲霉的影响。在这里，我们假设在CGD中性粒细胞中Olfm 4的缺失可以通过非氧化机制恢复微生物杀伤活性。 我们已经表明，细胞内杀伤和体内清除S。金黄色葡萄球菌，以及对S.与CGD小鼠相比，gp 91 phox和Olfm 4双缺陷小鼠中金黄色葡萄球菌脓毒症的发生率显著增加。Olfm 4基因缺陷小鼠、gp 91 phox和Olfm 4基因双缺陷小鼠的组织蛋白酶C及其下游蛋白酶（中性粒细胞弹性蛋白酶和组织蛋白酶G）活性和血清IL 1、IL 6、IL 12 p40、CXCL 2、G-CSF和GM-CSF水平均显著高于WT和CGD小鼠。金黄色。然而，我们没有观察到对A的增强防御。使用肺感染模型在Olfm 4缺陷型小鼠中检测烟曲霉毒素。这些结果表明Olfm 4缺失可以成功地增强针对S. aureus，而不是A. CGD小鼠中的烟曲霉毒素。为了确定Olfm 4基因缺失对S.金黄色葡萄球菌的免疫防御是通过TLR-MyD 88途径介导的，我们研究了MyD 88和Olfm 4双缺陷小鼠对金黄色葡萄球菌的宿主防御。金黄色葡萄球菌全身感染而MyD 88缺陷小鼠对S.金黄色葡萄球菌感染后，额外的Olfm 4消除显著改善了MyD 88缺陷小鼠的存活率，并提高了一些NF-B靶向的促炎细胞因子和趋化因子的血清水平。这些结果表明，由于Olfm 4缺失而增强的小鼠先天免疫是TLR-MyD 88信号不依赖的，并且NOD介导的NF-B可能起重要作用。 综上所述，我们发现Olfm 4的缺失，一个关键的中性粒细胞蛋白酶活性和NOD介导的途径的负调控因子，可以增强对S.金黄色葡萄球菌感染的CGD小鼠。这一发现提供了可能通过调节OLFM 4水平来增强CGD患者对细菌感染的防御的理论基础。OLFM 4可能被证明是CGD患者增强宿主对细菌感染的防御的重要靶点。

Chronic granulomatous disease (CGD) patients have recurrent life-threatening bacterial and fungal infections. Olfactomedin 4 (OLFM4) is a neutrophil granule protein that negatively regulates host defense against bacterial infection. The goal of this study was to evaluate the impact of Olfm4 deletion on host defense against Staphylococcus aureus and Aspergillus fumigatus in a murine X-linked CGD model. Here we hypothesize that deletion of Olfm4 in CGD neutrophils may restore microbe-killing activities through nonoxidative mechanisms. We have shown that intracellular killing and in vivo clearance of S. aureus, as well as resistance to S. aureus sepsis, were significantly increased in gp91phox and Olfm4 double-deficient mice compared with CGD mice. Activities of cathepsin C and its downstream proteases (neutrophil elastase and cathepsin G) and serum levels of IL1β, IL6, IL12 p40, CXCL2, G-CSF, and GM-CSF in Olfm4-deficient as well as gp91phox and Olfm4 double-deficient mice were significantly higher than those in WT as well as CGD mice after challenged with S. aureus. However, we did not observe enhanced defense against A. fumigatus in Olfm4-deficient mice using a lung-infection model. These results show that Olfm4 deletion can successfully enhance immune defense against S. aureus, but not A. fumigatus in CGD mice. To determine whether the effect of Olfm4 deletion on S. aureus immune defense is mediated through the TLR-MyD88 pathway, we investigated the host defense of MyD88 and Olfm4 double-deficient mice against S. aureus systemic infection. While the MyD88 deficient mice were highly susceptible to S. aureus infection, additional Olfm4 elimination remarkably improved the survival of MyD88-deficient mice and enhanced the serum levels of some NF-κB targeted pro-inflammatory cytokines and chemokines. These results suggest that enhanced mouse innate immunity due to Olfm4 deletion is TLR-MyD88 signal independent, and that NOD-mediated NF-κB may play an important role. Taken together, we found that deletion of Olfm4, a critical negative regulator of neutrophil protease activities and the NOD-mediated pathway, could enhance the immune defense against S. aureus infection in CGD mice. This finding provides a rationale to enhance CGD patient defense against bacterial infections potentially through the modulation of OLFM4 levels. OLFM4 might prove to be an important target in CGD patients to augment host defense against bacterial infection.