The -172A>G polymorphism in ADAM17 promoter region enhances its binding to EGR1 and confers susceptibility to sepsis progression

Abstract

Background: A disintegrin and metalloproteinase 17 (ADAM17) is a proteolytic cleaving protein with a crucial function in inflammatory responses, especially sepsis. But the clear role of ADAM17 in sepsis and the underlying mechanism remained unknown. In this study, we aim to determine the clinical relevance of the ADAM17 rs12692386 (-172A>G) promoter polymorphism in sepsis progression and to further explore the effect and mechanism of the early growth response 1 (EGR1) /ADAM17 pathway in the inflammatory process following sepsis. Methods: A case-control study with a total of 903 sepsis patients and 1150 controls were enrolled to determine the association of ADAM17 -172A>G polymorphism with sepsis. The transcription factor binding to the promoter region of ADAM17 gene was predicted by bioinformatics analysis and verified by Chromatin Immunoprecipitation (ChIP) and luciferase assays. Quantitative real-time PCR and Western blot were performed to detect EGR1 and ADAM17 expression. Cytokine production was detected by enzyme-linked immunosorbent assay. The effect of EGR1/ADAM17 pathway on sepsis-induced inflammatory responses was evaluated in EGR1-silenced cells and endotoxemia mouse model.Results: Patients with sepsis subtype exhibited significantly lower frequencies of the -172AG/GG genotypes compared to those with severe sepsis (29.3% vs. 45.9%, P=0.0002) or septic shock (29.3% vs. 42.4%, P=0.0032). The frequency of -172G allele in the 28-day non-surviving patients was significantly higher than that in the surviving patients (29.3% vs. 21.8%, P=0.0188). The results of in vitro lipopolysaccharide-stimulated and luciferase assays indicated that the −172 A-to-G variation could functionally upregulate promoter activity and transcription of ADAM17 gene via enhancing the binding affinity of its promoter region with the EGR1. The ChIP assay identified the direct interaction. Further studies demonstrated that the EGR1/ADAM17 intervention could significantly decrease the pro-inflammatory cytokine secretion in vitro and improve the survival and inflammatory response of sepsis mouse model.Conclusions: These results provide evidence that the ADAM17 -172A>G polymorphism can functionally enhance ADAM17 expression and promote sepsis-induced inflammatory responses via the EGR1/ADAM17 pathway, which ultimately promote sepsis progression and poor prognosis.