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

嗅介素4调节嗜中性粒细胞对S. aureus和E.通过抑制组织蛋白酶C介导的蛋白酶活性， 中性粒细胞通常通过氧化和非氧化机制杀死细菌。尽管许多研究集中在嗜中性粒细胞杀伤所必需的酶上，但对负责这种杀伤的调节分子知之甚少。在这项研究中，我们研究了嗅觉调节素4（OLFM 4），嗅觉调节素相关的糖蛋白，在中性粒细胞杀菌能力和宿主先天免疫的作用。中性粒细胞 OLFM 4-/-小鼠在体外增加了对金黄色葡萄球菌和大肠杆菌的细胞内杀伤。OLFM 4-/-小鼠增强了体内细菌清除，并且在用S. aureus或E.大肠杆菌感染。OLFM 4被发现与组织蛋白酶C相互作用，组织蛋白酶C是一种半胱氨酸蛋白酶，在细菌杀伤和免疫调节中起重要作用。我们证明了OLFM 4在体外和体内抑制组织蛋白酶C活性。OLFM 4-/-小鼠的中性粒细胞中的组织蛋白酶C活性显著高于野生型同窝小鼠的中性粒细胞。三个丝氨酸蛋白酶（中性粒细胞弹性蛋白酶，组织蛋白酶G和蛋白酶3），这需要组织蛋白酶C活性的加工和成熟，也显着更高的OLFM 4-/-中性粒细胞。在OLFM 4-/-小鼠中观察到的相对于WT小鼠增强的细菌杀伤和清除能力被OLFM 4和组织蛋白酶C双重缺陷的小鼠中组织蛋白酶C的额外损失显著损害。这些结果表明，OLFM 4是通过限制组织蛋白酶C活性及其下游颗粒相关丝氨酸蛋白酶来调节嗜中性粒细胞杀菌活性的重要负调节剂。 OLFM 4基因缺失可挽救小鼠X连锁慢性肉芽肿病中宿主对金黄色葡萄球菌的防御缺陷，但不能挽救烟曲霉菌 慢性肉芽肿病（CGD）患者由于呼吸爆发氧化酶（NADPH-氧化酶）四个亚基之一的突变而具有反复的危及生命的细菌和真菌感染。嗅觉调节蛋白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。我们的目的是评估OLFM 4缺失对宿主防御金黄色葡萄球菌和烟曲霉菌在小鼠X-连锁CGD模型的影响。我们发现，细胞内杀伤以及体内清除S。金黄色葡萄球菌（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。但双虚对宿主防御肺部感染的能力无影响。烟熏。这些结果表明OLFM 4缺失可以成功地挽救针对S. aureus，而不是A. CGD小鼠中的烟曲霉毒素。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。

Olfactomedin 4 modulates neutrophil killing of S. aureus and E. coli in mice through inhibiting cathepsin C-mediated protease activities Neutrophils kill bacteria generally through oxidative and nonoxidative mechanisms. Whereas much research has focused on the enzymes essential for neutrophil killing, little is known about the regulatory molecules responsible for such killing. In this study we investigated the role of olfactomedin 4 (OLFM4), an olfactomedin-related glycoprotein, in neutrophil bactericidal capability and host innate immunity. Neutrophils from OLFM4-/- mice have increased intracellular killing of Staphylococcus aureus and Escherichia coli in vitro. The OLFM4-/- mice have enhanced in vivo bacterial clearance and are more resistant to sepsis when challenged with S. aureus or E. coli by intraperitoneal injection. OLFM4 was found to interact with cathepsin C, a cysteine protease that plays an important role in bacterial killing and immune regulation. We demonstrated that OLFM4 inhibited cathepsin C activity in vitro and in vivo. The cathepsin C activity in neutrophils from OLFM4-/- mice was significantly higher than that in neutrophils from wild-type littermate mice. The activities of three serine proteases (neutrophil elastase, cathepsin G, and proteinase 3), which require cathepsin C activity for processing and maturity, were also significantly higher in OLFM4-/- neutrophils. The bacterial killing and clearance capabilities observed in OLFM4-/- mice that was enhanced relative to WT mice was significantly compromised by the additional loss of cathepsin C in mice with OLFM4 and cathepsin C double deficiency. These results indicate that OLFM4 is an important negative regulator of neutrophil bactericidal activity by restricting cathepsin C activity and its downstream granule-associated serine proteases. Deletion of OLFM4 Rescues Defective Host Defense Against Staphylococcus aureus, but not Aspergillus fumigatus in Murine X-linked Chronic Granulomatous Disease Chronic granulomatous disease (CGD) patients have recurrent life-threating bacterial and fungal infections due to the mutation of one of four subunits of the respiratory burst oxidase (NADPH-oxidase). Olfactomedin 4 (OLFM4) is a neutrophil granule protein that negatively regulates host defense against bacteria infection. We aimed to evaluate the impact of OLFM4 deletion on host defense against Staphylococcus aureus and Aspergillus fumigatus in a murine X-linked CGD model. We found that intracellular killings as well as in vivo clearance of S. aureus, and resistance to S. aureus sepsis were significantly increased in gp91phox-and OLFM4-double deficient mice compared with CGD mice. However, double deficiency had no effect on host defense against pulmonary infection by A. fumigatus. These results show that OLFM4 deletion can successfully rescue immune deficiency against S. aureus, but not A. fumigatus in CGD mice. OLFM4 might prove to be an important target in CGD patients to augment host defense against bacterial infection.