Department of Emergency Medicine, Seoul National University College of Medicine, 103 Daehak-ro, Jongno-gu, Seoul 03080, Republic of Korea.
Department of Emergency Medicine, Seoul National University Hospital, 101 Daehak-ro, Jongno-gu, Seoul 03080, Republic of Korea.
J Leukoc Biol. 2024 Nov 4;116(5):1169-1183. doi: 10.1093/jleuko/qiae169.
During recovery from septic shock, circulating mitochondrial N-formyl peptides predispose to secondary infection by occupying formyl peptide receptor 1 on the neutrophil (polymorphonuclear leukocyte) membrane, suppressing cytosolic calcium ([Ca2+]i)-dependent responses to secondarily encountered bacteria. However, no study has yet investigated therapeutic clearance of circulating mitochondrial N-formyl peptides in clinical settings. Thus, we studied how to remove mitochondrial N-formyl peptides from septic-shock plasma and whether such removal could preserve cell-surface formyl peptide receptor 1 and restore sepsis-induced polymorphonuclear leukocyte dysfunction by normalizing [Ca2+]i flux. In in vitro model systems, mitochondrial N-formyl peptide removal rescued polymorphonuclear leukocyte formyl peptide receptor 1-mediated [Ca2+]i flux and chemotaxis that had been suppressed by prior mitochondrial N-formyl peptide exposure. However, polymorphonuclear leukocyte functional recovery occurred in a stepwise fashion over 30 to 90 min. Intracellular Ca2+-calmodulin appears to contribute to this delay. In ex vivo model, systems using blood samples obtained from patients with septic shock, antimitochondrial N-formyl peptide antibodies alone failed to eliminate mitochondrial N-formyl peptides from septic-shock plasma or inhibit mitochondrial N-formyl peptide activity. We therefore created a beads-based antimitochondrial N-formyl peptide antibody cocktail by combining protein A/sepharose with antibodies specific for the most potent human mitochondrial N-formyl peptide chemoattractants. The beads-based antimitochondrial N-formyl peptide antibody cocktail treatment successfully removed those active mitochondrial N-formyl peptides from septic-shock plasma. Furthermore, the beads-based antimitochondrial N-formyl peptide antibody cocktail treatment significantly restored chemotactic and bactericidal dysfunction of polymorphonuclear leukocytes obtained from patients with septic shock who developed secondary infections. By clearing circulating mitochondrial N-formyl peptides, the immobilized antimitochondrial N-formyl peptide antibody therapy prevented mitochondrial N-formyl peptide interactions with surface formyl peptide receptor 1, thereby restoring [Ca2+]i-dependent polymorphonuclear leukocyte antimicrobial function in clinical septic-shock environments. This approach may help prevent the development of secondary, nosocomial infections in patients recovering from septic shock.
在脓毒性休克的恢复过程中，循环线粒体 N-甲酰肽通过占据中性粒细胞（多形核白细胞）膜上的形式肽受体 1，抑制对二次遇到的细菌的细胞质钙 ([Ca2+]i) 依赖性反应，从而易患二次感染。然而，尚无研究调查临床环境中循环线粒体 N-甲酰肽的治疗清除情况。因此，我们研究了如何从脓毒性休克血浆中去除线粒体 N-甲酰肽，以及这种去除是否可以通过使 [Ca2+]i 通量正常化来保留细胞表面形式肽受体 1 并恢复脓毒症引起的多形核白细胞功能障碍。在体外模型系统中，线粒体 N-甲酰肽去除挽救了先前线粒体 N-甲酰肽暴露抑制的多形核白细胞形式肽受体 1 介导的 [Ca2+]i 通量和趋化性。然而，多形核白细胞功能恢复以 30 到 90 分钟的步幅发生。细胞内钙-钙调蛋白似乎对此延迟有贡献。在使用从脓毒性休克患者获得的血液样本的离体模型系统中，单独的抗线粒体 N-甲酰肽抗体未能从脓毒性休克血浆中消除线粒体 N-甲酰肽或抑制线粒体 N-甲酰肽活性。因此，我们通过将蛋白 A/琼脂糖与针对最有效的人类线粒体 N-甲酰肽趋化剂的抗体相结合，创建了基于珠的抗线粒体 N-甲酰肽抗体鸡尾酒。基于珠的抗线粒体 N-甲酰肽抗体鸡尾酒治疗成功地从脓毒性休克血浆中去除了那些活性线粒体 N-甲酰肽。此外，基于珠的抗线粒体 N-甲酰肽抗体鸡尾酒治疗显著恢复了从发生二次感染的脓毒性休克患者获得的多形核白细胞的趋化和杀菌功能障碍。通过清除循环线粒体 N-甲酰肽，固定化抗线粒体 N-甲酰肽抗体疗法阻止了线粒体 N-甲酰肽与表面形式肽受体 1 的相互作用，从而在临床脓毒性休克环境中恢复了 [Ca2+]i 依赖性多形核白细胞抗菌功能。这种方法可能有助于防止从脓毒性休克中恢复的患者发生二次医院获得性感染。
