Differential Expression of microRNAs following activated protein C treatment in a rat model of septic shock

Sepsis induces systemic stress by augmenting inflammatory and pro-coagulant responses resulting in microvascular dysfunction and end organ failure, events modulated by the Protein C pathway. MicroRNAs (miRNAs) are small non-coding RNAs involved in post-transcriptional regulation of gene transcription yet their role in sepsis remains poorly defined. We hypothesized that aPC selectively alters the expression of specific miRNAs implicated in protection of hepatic function during septic shock. Male Sprague-Dawley rats underwent sham surgery or cecal ligation and puncture (CLP). Twenty-four later, animals were randomized and treated with aPC (1mg/kg) or vehicle (0.9% (w/v) saline) via an indwelling venous catheter at 12 hour intervals for 24 hours. Gene array was performed on hepatic RNA to determine miRNA expression, and predicted mRNA targets determined using a bioinformatics approach. Of 351 rat miRNAs examined by microarray hybridization, 17 were highly expressed during sepsis and restored to basal levels after aPC treatment. In silico analysis identified 9 miRNAs significantly regulating target genes of the focal adhesion pathway. These data suggest aPC treatment coordinates beneficial cytoprotective effects during sepsis by modulating miRNA expression. While translational effects remain to be fully elucidated in a clinical setting, we demonstrate herein the potential experimental and computational benefits for use of microRNA analysis in sepsis.脓毒症（Sepsis）通过增强炎症与促凝血反应诱发全身应激，进而引发微血管功能障碍及终末器官衰竭，此类病理事件受蛋白C（Protein C）通路调控。微小RNA（miRNAs）是一类参与基因转录后调控的小型非编码RNA，但其在脓毒症中的作用仍未得到充分阐明。本研究提出假说：活化蛋白C（activated Protein C，aPC）可在脓毒性休克期间，选择性改变与肝功能保护相关的特定miRNAs的表达水平。实验选用雄性斯普拉格-道利（Sprague-Dawley）大鼠，分别接受假手术或盲肠结扎穿刺术（cecal ligation and puncture，CLP）造模。造模24小时后，将大鼠随机分组，通过留置静脉导管每12小时给予aPC（1mg/kg）或溶剂（0.9%[w/v]生理盐水），持续给药24小时。采集肝组织RNA进行基因芯片检测以分析miRNAs表达谱，并通过生物信息学方法预测其mRNA靶标基因。在芯片杂交检测的351种大鼠miRNAs中，17种在脓毒症模型中呈高表达状态，经aPC治疗后恢复至基础水平。计算机模拟（in silico）分析显示，其中9种miRNAs可显著调控黏着斑（focal adhesion）通路的靶基因。本研究数据表明，aPC治疗可通过调控miRNAs的表达，在脓毒症进程中介导协同性的有益细胞保护效应。尽管其临床转化效应仍需在临床场景中进一步全面阐明，但本研究证实了miRNAs分析在脓毒症研究中所具备的实验与计算生物学应用价值。