The SGLT2I Dapagliflozin reverses metabolic stress driving myocardial inflammation in a mouse model of heart failure with preserved ejection fraction: insights from single-cell RNA sequencing

Abstract Background Heart failure with preserved ejection fraction (HFpEF) is often associated with metabolic distress and represents a therapeutic challenge. Metabolism-induced systemic inflammation links comorbidities with HFpEF. How metabolic changes impact myocardial inflammation in the context of HFpEF is not known. Methods We generated a model of metabolic HFpEF by feeding ApoE knockout (ApoE KO) mice a high-fat diet (HFD), and used single-cell expression analysis (scRNA-seq) on CD45+ cardiac cells to evaluate the involvement of inflammation. By focusing our analysis on macrophages, we obtained high-resolution identification of subsets of these cells in the heart, enabling us to study the outcomes of metabolic distress on the cardiac macrophage infiltrate and identify a macrophage-to-cardiomyocyte (CMC) regulatory axis. To test whether a clinically relevant sodium glucose cotransporter-2 inhibitor (SGLT2i) could ameliorate the cardiac immune infiltrate profile in our model, ApoE KO-HDF mice were randomized to receive the SGLT2i dapagliflozin (DAPA) or vehicle for 8 weeks. Results We describe a new metabolic HFpEF model: mice present with reduced diastolic function, reduced exercise tolerance, and increased pulmonary congestion associated with cardiac lipid overload and reduced polyunsaturated fatty acids. The main immune cell types infiltrating the heart included 4 sub-populations of resident and monocyte-derived macrophages displaying a pro-inflammatory profile exclusively in ApoE KO-HFD mice. Lipid overload had a direct effect on inflammatory gene activation in macrophages, mediated through endoplasmic-reticulum stress pathways. Investigation of the macrophage-to-CMC regulatory axis revealed the potential effects on CMCs of multiple inflammatory cytokines secreted by macrophages, impacting pathways such as hypertrophy, fibrosis, and autophagy. Finally, we describe the anti-inflammatory effect of SGLT2i. Conclusions Through a newly described model of HFpEF based on metabolic stress, and using scRNA-seq, we have determined the effects of metabolic distress on cardiac inflammatory cells, in particular on macrophages, and suggest SGLT2i as potential therapeutic agents for the targeting of a specific phenotype of HFpEF.