STUB1 and heart failure: To investigate potential interactions of monocytes with cardiac cell types, we integrated single-cell RNA-sequencing data from circulating monocytes derived from patients with chronic heart failure with reduced ejection fraction (HFrEF), who either carried DNMT3A CHIP-driver mutations (n = 5) or were No-CHIP carriers (n = 4)15, with publicly available single-nuclei RNA-sequencing data of human healthy heart tissue (n = 14)23 and from heart failure with reduced ejection fraction (HFrEF) patients (n = 3) (Fig. 1a, b and Supplementary Table 1).