Blake, M.; Prins, S.; Blake, J.; Hartweck, L. M.; Mendelson, J. B.; Provencher, S.; Breuils-Bonnet, S.; Bonnet, S.; Prins, K.

Right ventricular failure (RVF) is a robust predictor of mortality in pulmonary arterial hypertension (PAH); however, the mechanisms linking RVF to end-organ dysfunction remain unclear. Hepatic impairments portend poor outcomes in PAH, but the cell-specific effects of PAH on the human liver are unknown. Here, we performed single nucleus RNA sequencing on autopsy-derived liver tissue from five PAH patients and four non-PAH controls and compared these findings to non-alcoholic steatohepatitis (NASH) and Fontan-associated liver disease (FALD). PAH hepatocytes were characterized by a pro-proliferative, Warburg-like metabolic phenotype. PAH endothelial cells (ECs) also adopted a Warburg-like profile. Although EC PI3K-Akt activation was present in PAH and FALD ECs, only PAH ECs demonstrated impaired adhesion/barrier signaling. In PAH hepatic stellate cells (HSCs), PI3K-Akt signaling was enriched, while NASH and FALD HSCs co-activated PI3K-Akt and TGF-b;. Activated HSC abundances were increased in PAH livers and associated with heightened central vein fibrosis. PAH and NASH macrophages showed elevated complement signaling but reduced JAK-STAT activity. PAH livers exhibited dysregulated vasoactive gene expression, increased interleukin-6 expression in HSCs, and suppressed hepatocyte ketone metabolism. Correlational analysis demonstrated that HSC HIF-1 activation was associated with PAH severity. In total, these findings define the metabolic and inflammatory hepatopathy of PAH.