MicroRNA expression following activated protein C treatment during septic shock

BackgroundSepsis induces systemic stress by augmenting inflammatory and procoagulant responses, resulting in microvascular dysfunction and end organ failure, events modulated by the protein C pathway. MicroRNAs (miRNAs) are small noncoding RNAs involved in post-transcriptional regulation of genes; yet, their role in sepsis is poorly defined. We hypothesized that activated protein C (aPC) selectively alters specific miRNA expression implicated in protection of hepatic function during septic shock.MethodsMale Sprague-Dawley rats underwent sham or cecal ligation and puncture surgery; 24 h later, we randomized them to aPC (1 mg/kg) or vehicle (0.9% [w/v] saline) treatment via an indwelling venous catheter (12-h intervals for 24 h). We performed gene array and quantitative reverse transcriptase–polymerase chain reaction analysis on hepatic RNA to determine miRNA expression and determined predicted mRNA targets using a bioinformatics approach. We confirmed beneficial effects of aPC treatment in the cecal ligation and puncture model of sepsis by survival and blood chemistries, and histologically.ResultsOf 351 rat miRNAs examined, 17 were highly expressed during sepsis and restored to basal levels after aPC treatment. We confirmed expression of select miRNAs (miR-182, -199a-5p, -203, -211, -222, and -29b) using quantitative reverse transcriptase–polymerase chain reaction. In silico analysis identified nine miRNAs significantly regulating target genes of the focal adhesion pathway.ConclusionsThese data suggest that aPC treatment coordinates beneficial cytoprotective effects during sepsis by modulating miRNA expression. Whereas translational effects remain to be fully elucidated in a clinical setting, we demonstrate here the potential experimental and computational benefits of using of microRNA analysis in sepsis.