Inhibition of transmembrane TNF-\u03b1 shedding by a specific antibody protects against septic shock

Chenxi Li,Bingjiao Yin,Jing Wang,Peng Yang,Meng Zhang,Zhuoya Li,Mingxia Yu,Haiyan Gu,Yue Yin,Hongping Ba,Xiaoxi Zhou

doi:10.1038/s41419-019-1808-6

Abstract

Transmembrane TNF-α (tmTNF-α) and secretory TNF-α (sTNF-α) display opposite effects in septic shock. Reducing tmTNF-α shedding can offset the detrimental effects of sTNF-α and increase the beneficial effect of tmTNF-α. We previously developed a monoclonal antibody that is specific for tmTNF-α and does not cross-react with sTNF-α. In this study, we show that this antibody can specifically suppress tmTNF-α shedding by competing with a TNF-α converting enzyme that cleaves the tmTNF-α ectodomain to release sTNF-α. This tmTNF-α antibody significantly inhibited LPS-induced secretion of interleukin (IL)-1β, IL-6, interferon-β, and nitric oxide by monocytes/macrophages, and protected mice from septic shock induced by lipopolysaccharide (LPS) or cecal ligation and puncture, while reducing the bacterial load. The mechanism associated with the protective effect of this tmTNF-α antibody involved promotion of LPS-induced toll-like receptor 4 (TLR4) internalization and degradation by recruiting Triad3A to TLR4. Moreover, the tmTNF-α antibody inhibited LPS-induced activation of nuclear factor-κB and interferon regulatory factor 3 pathways by upregulating expression of A20 and monocyte chemotactic protein-induced protein 1. Similarly, treatment of macrophages with exogenous tmTNF-α suppressed LPS/TLR4 signaling and release of proinflammatory cytokines, indicating that increased levels of tmTNF-α promoted by the antibody contributed to its inhibitory effect. Thus, use of this tmTNF-α antibody for specific suppression of tmTNF-α shedding may be a promising strategy to treat septic shock.

Highlights

1234567890():,; 1234567890():,; 1234567890():,; 1234567890():,; Introduction Tumor necrosis factor-α (TNF-α) is first synthesized as transmembrane TNF-α, which is cleaved by the TNF-α converting enzyme (TACE) to release secretory TNF-α1,2. sTNF-α is widely recognized as a prototypic inflammatory cytokine that plays a pivotal role in the pathogenesis of early endotoxin shock[3,4,5]
This antibody effectively kills transmembrane TNF-α (tmTNF-α) expressing breast cancer cells[18] and leukemia cells[19] by antibodydependent cell-mediated cytotoxicity and complementdependent cytotoxicity. We show that this tmTNF-α monoclonal antibody (mAb) can compete with TACE for binding to tmTNF-α and inhibit tmTNF-α ectodomain shedding to protect against endotoxin shock by facilitating LPSinduced toll-like receptor 4 (TLR4) internalization and degradation, and actively suppressing TLR4 signaling pathways
As the epitope recognized by tmTNF-α mAb is closer to the TACE cleavage site, we hypothesized that tmTNF-α

Summary

Introduction

Tumor necrosis factor-α (TNF-α) is first synthesized as transmembrane TNF-α (tmTNF-α), which is cleaved by the TNF-α converting enzyme (TACE) to release secretory TNF-α (sTNF-α)1,2. sTNF-α is widely recognized as a prototypic inflammatory cytokine that plays a pivotal role in the pathogenesis of early endotoxin shock[3,4,5]. Our previous study revealed that, compared with a transient elevation in the levels of serum sTNF-α at 90 min after injection of bacterial into rats, tmTNF-α expression on peritoneal macrophages and liver tissue increased gradually, to peak at 4.5 h after injection, and declined and stabilized at relatively higher levels up to 24 h after induction of endotoxin shock[8]. This finding indicates a role of tmTNF-α in sepsis. These data imply that tmTNF-α, unlike sTNF-α, is beneficial in controlling sepsis and septic shock

Methods

Results

Conclusion