Dataset Information

Investigation of Association of Complement 5 Genetic Polymorphisms with Sepsis and Sepsis-Induced Inflammatory Responses.

ABSTRACT:

Background

Complement 5 (C5) and C5a production play a pivotal role in the pathophysiology of sepsis. Strong evidence demonstrates an association of C5 gene polymorphisms with various inflammatory diseases. However, no current studies have explored the clinical relevance of C5 polymorphisms in sepsis.

Methods

Two C5 gene polymorphisms, rs17611 and rs2269067, were identified by genotyping in 636 sepsis patients and 753 controls in a Han Chinese population. C5 gene expression was detected via quantitative real-time PCR. C5a and proinflammatory cytokine production was measured by enzyme-linked immunosorbent assay. An Annexin V apoptosis assay was performed to assess cell apoptosis.

Results

Our results showed significantly lower frequencies of rs2269067 GC/CC genotypes or C allele in sepsis patients than healthy controls. The frequencies of rs17611 CC/CT genotypes or C allele were significantly overrepresented in both the septic shock and non-survivor subgroups. Patients with this sepsis-associated high-risk rs17611 C allele exhibited a significant increase in C5a, TNF-α and IL-6 production. However, no significant difference in C5a and downstream proinflammatory cytokine production was observed among patients with different rs2269067 genotypes. In addition, in vitro experiments showed an effect of recombinant C5a on enhancing LPS-stimulated IL-1β, IL-6 and TNF-α production and cell apoptosis in THP-1 monocytes.

Conclusion

The rs2269067 polymorphism conferred protection against sepsis susceptibility. The rs17611 polymorphism was associated with increased C5a production, which ultimately potentiated the secretion of downstream proinflammatory cytokines and conferred susceptibility to sepsis progression and poor prognosis.

SUBMITTER: Chen K

PROVIDER: S-EPMC8648101 | biostudies-literature |

REPOSITORIES: biostudies-literature

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Project description:BACKGROUND:Previous studies have identified critical roles of IL-27 in the pathological mechanisms of sepsis, and blockade of IL-27 may be a promising alternative therapy for sepsis. The purpose of this study was to evaluate the clinical relevance of IL-27 genetic polymorphisms in sepsis and to further characterize their effect on IL-27 expression and inflammatory processes following sepsis. METHODS:A total of 885 septic patients and 1101 healthy controls were enrolled and genotyped for IL-27 genetic variants (rs153109/-964A?>?G and rs17855750/2905 T?>?G). Quantitative real-time PCR and enzyme-linked immunosorbent assays were performed to detect IL-27 expression and cytokine production. The effect of the rs153109 polymorphism on IL-27 promoter activity was evaluated using a luciferase reporter assay, and THP-1 cell apoptosis was calculated using an annexin V apoptosis assay. RESULTS:No significant differences in the genotype/allele frequencies were observed between patients with sepsis and healthy controls, suggesting that these two IL-27 polymorphisms may not influence susceptibility to sepsis. The -964AA genotype was overrepresented in patients with severe sepsis/septic shock relative to patients with the sepsis subtype, and the A allele was significantly associated with 28-mortality in sepsis. Patients carrying the -964AA genotype exhibited significantly higher expression levels of IL-27 than the GA/GG genotype carriers. The results of an in vitro (lipopolysaccharide (LPS))-stimulated experiment showed that this sepsis-associated high-risk AA genotype significantly increased IL-27 levels and enhanced TNF-? and IL-1? production in the peripheral blood mononuclear cells (PBMCs) upon exposure to LPS in vitro. Furthermore, luciferase reporter assays indicated that the high-risk -964A allele resulted in increased promoter activities compared to the non-risk allele in THP-1 and 293 T cells. Additionally, IL-27 treatment significantly enhanced TNF-? and IL-6 secretion and apoptosis of THP-1 cells upon LPS stimulation. CONCLUSIONS:These results provided evidence that the IL-27 -964A?>?G polymorphism functionally enhanced IL-27 expression and promoted sepsis-induced inflammatory responses, which ultimately resulted in promoting the progression of sepsis and poor prognosis.

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