Abstract 13972: Metabolic Reprogramming of Diabetic Mesenchymal Stromal Cells by Inhibiting Glypican 3 Enhances Their Cardioprotective Functions via Pyruvate Kinase Activation

Abstract

Mesenchymal stromal cells (MSC) represent promising stem cell therapy for the treatment of cardiovascular diseases. Diabetes affects the functional capability of MSC and is an impediment to cell-based therapy. However, the impact of diabetes on MSC myocardial reparative activity, metabolic fingerprint, and the mechanism of dysfunction is still poorly understood. Therefore, our study aimed to understand the molecular basis of diabetes-induced MSC functions and their metabolic mechanism, and potential metabolic reprogramming of diabetic MSC to reverse these dysfunctions may represent a strategy to enhance cell-based therapeutics for myocardial repair in diabetic patients. The seahorse and 13 C glucose tracing studies identified defective energy metabolism in db/db-MSC. Our data also shows the diminished functional activity of db/db-MSCs to improve post-MI cardiac functions. Furthermore, we found that glypican-3 (GPC3), a heparan sulfate proteoglycan, is highly upregulated in db/db-MSC when compared to WT-MSC. GPC3 overexpression in WT-MSC showed abrogated metabolic fingerprints, lowered immunosuppression activity, and reduced angiogenic potential. Interestingly, GPC3 knockdown in WT-MSC showed an improved metabolic state, increased immunosuppression activity, and enhanced angiogenic potential. Furthermore, GPC3 knockdown in diabetic MSC restored their energy metabolism and their functions. Mechanistically, we revealed that GPC3 binds to pyruvate kinase (PK), which subsequently increases the rate of glycolysis and ATP production. In a mouse model of myocardial infarction (MI), intramyocardial transplantation of GPC3-metabolic reprogrammed db/db-MSC promoting neovascularization (at 28 days, post-MI) and lower cardiac fibrosis, leading to improved left ventricular function. These findings indicate that diabetes increased GPC3 expression and altered the metabolic rates in MSC which is detrimental to its function, and transplantation of GPC3-metabolic reprogrammed db/db-MSC into ischemic myocardium promoted their cardiac functions. Thus, inhibiting GPC3 may potentially be used to restore the metabolic state and functions of db/db-MSC for cell therapy applications.