Using Chemo-Proteomics to Identify New SGLT2 Inhibitor Targets in the Heart

ABSTRACT Diseases caused by reduced or dysregulated contractile function of the heart are a major clinical problem. More than six million Americans have heart failure with either reduced (HFrEF) or preserved contractile function (HFpEF), and another ~700,000 Americans have inherited genetic mutations in the protein components of the contractile machinery that have been directly linked to inheritable heart diseases. The ‘four pillars’ of guideline-directed medical therapy for heart failure include beta-blockers, angiotensin receptor-neprilysin inhibitors, mineralocorticoid receptors antagonists and sodium-glucose co-transporter-2 inhibitors (SGLT2i). Although traditionally known as anti-hyperglycemic drugs that inhibit re-absorption of glucose and sodium in the kidneys, SGLT2i have established themselves as a pivotal part of modern heart failure therapy. In addition to the on-target effects in the kidneys, SGLT2i have been shown to have off- target effects in the heart that likely contribute to the cardiovascular benefits seen in heart failure patients. However, the precise molecular mechanisms of action of SGLT2i in the heart have remained unknown. We will use a chemo-proteomics approach to test the hypothesis that SGLT2i have a direct beneficial effect on the contractile cardiomyocytes. We will identify potential protein targets by incubating isolated cultured cardiomyocytes with custom-synthesized SGLT2i derivatives containing chemical ‘warheads’ that covalently link the drugs to their protein binding partners. Cells will subsequently be harvested, and protein targets identified via mass spectrometry and proteomics techniques. We will subsequently use the American Heart Association Protein Atlas and Precision Medicine Platform to analyze the mass spectrometry data, create an integrated map of the SGLT2i interactome and model the structure of the protein-drug complexes. The proposal will not only allow new mechanistic insights into SGLT2 inhibitor function in the heart but also underpin the development of potential new therapies for heart failure by identifying new targets for drug development.