Secher Thomas, Vasseur Virginie, Poisson Didier Marc, Mitchell Jane A, Cunha Fernando Q, Alves-Filho José Carlos, Ryffel Bernhard
Molecular Immunology and Embryology, University of Orleans and Centre National de la Recherche Scientifique, France.
J Immunol. 2009 Jun 15;182(12):7855-64. doi: 10.4049/jimmunol.0804008.
Sepsis is still a major cause of mortality in the intensive critical care unit and results from an overwhelming immune response to the infection. TNF signaling pathway plays a central role in the activation of innate immunity in response to pathogens. Using a model of polymicrobial sepsis by i.p. injection of cecal microflora, we demonstrate a critical role of TNFR1 and R2 activation in the deregulated immune responses and death associated with sepsis. A large and persistent production of TNF was found in wild-type (B6) mice. TNFR1/R2-deficient mice, compared with B6 mice, survive lethal polymicrobial infection with enhanced neutrophil recruitment and bacterial clearance in the peritoneal cavity. Absence of TNFR signaling leads to a decreased local and systemic inflammatory response with diminished organ injury. Furthermore, using TNFR1/R2-deficient mice, TNF was found to be responsible for a decrease in CXCR2 expression, explaining reduced neutrophil extravasation and migration to the infectious site, and in neutrophil apoptosis. In line with the clinical experience, administration of Enbrel, a TNF-neutralizing protein, induced however only a partial protection in B6 mice, with no improvement of clinical settings, suggesting that future TNF immunomodulatory strategies should target TNFR1 and R2. In conclusion, the present data suggest that the endogenous TNFR1/R2 signaling pathway in polymicrobial sepsis reduces neutrophil recruitment contributing to mortality and as opposed to pan-TNF blockade is an important therapeutic target for the treatment of polymicrobial sepsis.
脓毒症仍然是重症监护病房患者死亡的主要原因,是由对感染的过度免疫反应所致。肿瘤坏死因子(TNF)信号通路在病原体感染引发的固有免疫激活过程中发挥核心作用。通过腹腔注射盲肠微生物群建立多微生物脓毒症模型,我们证明了TNFR1和R2激活在脓毒症相关的免疫反应失调和死亡中起关键作用。野生型(B6)小鼠体内发现大量且持续产生TNF。与B6小鼠相比,TNFR1/R2基因敲除小鼠在致死性多微生物感染中存活下来,且腹腔内中性粒细胞募集增加、细菌清除增强。缺乏TNFR信号会导致局部和全身炎症反应减弱,器官损伤减轻。此外,利用TNFR1/R2基因敲除小鼠发现,TNF导致CXCR2表达下降,这解释了中性粒细胞渗出减少以及向感染部位迁移减少和中性粒细胞凋亡的原因。与临床经验一致,给予TNF中和蛋白恩利(Enbrel)仅能使B6小鼠获得部分保护,临床症状并无改善,这表明未来的TNF免疫调节策略应针对TNFR1和R2。总之,目前的数据表明,多微生物脓毒症中的内源性TNFR1/R2信号通路减少了中性粒细胞募集,这是导致死亡发生的原因,与泛TNF阻断不同,它是治疗多微生物脓毒症的重要治疗靶点。