Wednesday, May 8, 2024
5/8/2024
Project Summary Type 2 diabetes (T2D) is a leading cause of death nationwide, with 65% of mortality due to cardiovascular disease. The term “diabetic cardiomyopathy (T2DCM)” refers to a condition with adverse myocardial remodeling in the absence of hypertension and vascular pathology. Although T2D and CVD are tightly intertwined, we lack a deeper understanding of T2DCM at the molecular and cellular levels. Pathological mechanisms within the primary constituents of the heart – cardiomyocytes, fibroblasts, and endothelial cells – are incompletely understood. Furthermore, how these metabolic signals converge within the cardiac microenvironment remains elusive. First developed to treat T2D, sodium-glucose cotransporter-2 inhibitors (SGLT2i) prevent glucose reabsorption by the kidney. However, recent clinical trials of SGLT2i (canagliflozin, dapagliflozin, and empagliflozin) further demonstrated an unexpected and substantial reduction in heart failure hospitalizations in patients with and without T2D. Since SGLT2 is lowly expressed in the heart, its off-target mechanisms present a fascinating opportunity to elucidate cardiac protective targets beyond glycemic control. I hypothesize that metabolic interplay between cardiomyocytes, endothelial cells, and fibroblasts play a role in T2DCM pathogenesis, and SGLT2 inhibition is a tool to dissect cell-specific protective mechanisms. Since access to human cardiac samples is limited by primary culture or post-mortem autopsy, the pre-clinical testing of cardiovascular drugs difficult. Thus, induced pluripotent stem cells (iPSCs) have become a valuable platform for biomedical research by providing tissue-specific human cells that retain patients' genetic integrity and display disease phenotypes in a dish. In this F32 proposal, I will harness iPSC technology to generate T2DCM models of cardiovascular cell types for cellular and metabolic phenotyping with and without SGLT2 inhibition (Aim 1). The iPSCs of T2D patients (10 healthy, 20 T2D) are readily available from the Stanford Cardiovascular Institute Biobank. They will be differentiated into three cardiovascular cell types using robust protocols followed by contractility, mitochondrial oxygen consumption rate, cellular (viability, migration, proliferation), and metabolic function (13C-metabolomics) measurements. Next, I will construct iPSC-derived engineered heart tissues for functional phenotyping of cellular interplay (Aim 2). I will further determine the SGLT2i-protein interactome using limited proteolysis coupled to liquid chromatography-mass spectrometry (LiP-MS). Using a systems-level approach compatible with complex biological samples will enable elucidation of drug-protein interactions relevant to T2DCM with peptide-level resolution. In summary, this research plan presents a novel, comprehensive view of metabolic mechanisms conferred by T2DCM pathogenesis, and SGLT2 inhibition and can be used as a springboard for discovering new cardiac protective agents. Taken together, this project will bolster an innovative direction for the cardiovascular community while providing me with the necessary training to become an independent researcher of cardiac metabolic disease.
HHS’ Tracking Accountability in Government Grants System (TAGGS) website provides access to detailed descriptions of grants, loans, aggregated direct payments and other types of financial assistance awarded by the HHS Operating Divisions (OPDIVs) and the Office of the Secretary Staff Divisions (STAFFDIVs).
