DNA methylation of a NF-?B binding site in the aquaporin 5 promoter impacts on mortality in sepsis.

ABSTRACT: Altered aquaporin 5 (AQP5) expression in immune cells impacts on key mechanisms of inflammation and is associated with sepsis survival. Since epigenetic regulation via DNA methylation might contribute to a differential AQP5 expression in sepsis, we tested the hypotheses that DNA methylation of the AQP5 promotor (1) influences AQP5 expression, (2) is associated with the 30-day survival of septic patients, and (3) alters the nuclear transcription factor NF-?B binding. AQP5 mRNA expression was quantified by real-time PCR in whole blood samples of 135 septic patients. In silico computer analysis of the AQP5 promoter (nt-567 to nt-975) revealed seven putative inflammatory transcription factor binding sites and methylation of these sites was analyzed. Electrophoretic mobility shift assays were performed to assess the binding of nuclear NF-?B to the AQP5 promoter region nt-937. After adjustment for multiple testing, a greater methylation rate was found at cytosine site nt-937 in the AQP5 promoter linked to NF-?B binding in non-survivors compared to survivors (p?=?0.002, padj?=?0.014). This was associated with greater AQP5 mRNA expression in non-survivors (p?=?0.037). Greater (?16%) promoter methylation at nt-937 was also associated with an independently increased risk of death within 30 days (HR: 3.31; 95% CI: 1.54-6.23; p?=?0.002). We detected a functionally important AQP5 promoter cytosine site (nt-937) linked to the binding of the inflammatorily acting nuclear transcription factor NF-?B, with increased methylation in sepsis non-survivors. Thus, nt-937 APQ5 promoter methylation, presumably related to NF-?B binding, is prognostically relevant in sepsis and demonstrates that epigenetic changes impact on sepsis outcome.

SUBMITTER: Rump K 

PROVIDER: S-EPMC6898603 | biostudies-literature | 2019 Dec

REPOSITORIES: biostudies-literature