Human biopsy-defined ischemia-reperfusion injury-selective reperfusion signature prioritizes reperfusion-timed mitogen-activated protein kinase kinase inhibition after donation after circulatory death liver transplantation.

Early post-liver transplant ischemia-reperfusion injury (IRI) in donation after circulatory death grafts lacks therapies targeted to the immediate postreperfusion window, in part because generic reperfusion transcription obscures IRI-selective amplification. We analyzed paired prereperfusion/postreperfusion liver biopsies from 2 cohorts (GSE151648 and GSE87487) using a difference-in-differences interaction estimand (ΔΔ = [Post-Pre]IRI+ - [Post-Pre]IRI-) to define an IRI-selective early reperfusion program. Genome-wide ΔΔ effects were summarized using pathway-responsive genes, and pathway concordance was tested using permutation (B = 5000). The reproducible ΔΔ footprint highlighted epidermal growth factor receptor-mitogen-activated protein kinase signaling (Spearman ρ = 0.811; P = .001). Directional ΔΔ gene sets (interaction P < .05) were submitted to the L1000 characteristic direction signature search engine2; cross-cohort overlap identified 8 shared perturbagens, including 3 mitogen-activated protein kinase kinase (MEK)1/2 inhibitors. In a hepatic ischemia/reperfusion time course (GSE117915), epidermal growth factor receptor and mitogen-activated protein kinase activities increased within 0.5 hours of reperfusion, and transplant single-cell RNA sequencing (GSE189539) localized MEK/extracellular signal-regulated kinase pathway engagement predominantly to parenchymal cells. A representative MEK inhibitor, PD-0325901, reduced hepatocyte oxygen-glucose deprivation/reoxygenation injury and, when administered at reperfusion in a rat donation after circulatory death liver transplantation model (5-20 mg/kg), attenuated histologic and biochemical injury, apoptosis, and redox-inflammatory readouts and improved 7-day survival. Collectively, this biopsy-anchored ΔΔ interaction-phenotype framework, with cross-cohort concordance as a prespecified robustness gate, nominates reperfusion-timed MEK inhibition as a mechanism- and window-aligned strategy to blunt early post-liver transplant IRI.