Defining cardiac functional recovery in end-stage heart failure at single cell resolution
Recovery of cardiac function is the ultimate goal of heart failure therapy yet is infrequently observed and remains poorly understood. Here we characterize the cellular landscape and predictors of cardiac recovery by performing single nucleus RNA-sequencing (snRNA-seq) from 40 heart failure patients who recovered LV systolic function following left ventricular assist device (LVAD) implantation and patients who did not recover and non-diseased donors. We identify cell type specific transcriptional signatures of recovery in all cell types, most prominently in macrophages and fibroblasts. Pro-inflammatory macrophages and inflammatory signalling in fibroblasts were negative predictors of recovery, while downregulation of RUNX1 transcriptional activity in macrophages and fibroblasts was associated with recovery. In silico perturbation of RUNX1 in macrophages and fibroblasts recapitulated the transcriptional state of recovery. In a mouse model of cardiac recovery mediated by BRD4 inhibition, we observed a decrease in macrophage and fibroblast Runx1 expression, diminished chromatin accessibility within a Runx1 intronic peak, and acquisition of human recovery signatures. These findings suggest that cardiac recovery is a unique biological state and identify RUNX1 as a possible therapeutic target to facilitate cardiac recovery. Overall design: snRNA-seq in donor and HF (pre-post LVAD split by responders and non-responders)