Cold Storage of Lung Allograft Modulates microRNA-223 Expression & NF-kB-Mediated Reperfusion Response

Purpose Ischemia-reperfusion injury after lung transplantation is associated with worse clinical outcomes including primary graft dysfunction. Previously, microRNA (miR)-223 was shown to regulate the NF-kB pathway in lung injury models. Herein, we aim to examine the microRNA-mRNA interactions during human lung response to cold storage/ex-vivo lung perfusion (CS/EVLP) and identify correlations between miR-223 and the transcriptome. Methods Tissue samples were obtained from 5 human lungs after CS and after 2hrs of EVLP. Control samples were obtained from 5 different donors without CS/EVLP. The NanoString platform was used for miR profiling and mRNA sequencing. Ingenuity Pathway Analysis was used to study network interactions between miR expression and the transcriptome. Validation in vitro experiments were performed in a specialized oxygenation chamber using A549 cells. Results Microarray analysis showed significant differential expression of 44 mRNA & 123 microRNA after cold storage, and 61 mRNA & 157 miR after EVLP compared to control (p 5 fold). Showing in the in-vitro model, miR-223 was down-regulated in A549 cells during reperfusion (20-22°C, 40% O2) after 4 hr of CS (4°C, 100% O2) while it was up-regulated when the experiment repeated under normothermia conditions storage (20-22°C, 100% O2). Conclusion This study provides for the first time evidence for miR-223 targeting NF-kB pathway in human lung response to CS/EVLP which could serve as a novel therapy to mitigate reperfusion injury. The finding that CS modulates miR-223 expression in human lungs is novel and warrant further investigation.