Hyperglycemia Altered the Fate of Cardiac Stem Cells to Adipogenesis through Inhibiting the β-Catenin/TCF-4 Pathway

Hyperglycemia is an important risk factor for the most severe cardiovascular diseases in patients with diabetes. It has been demonstrated that cardiac stem cells (CSCs) play a pivotal role in the maintenance of cardiac homeostasis and regeneration. However, the mechanism underlying the influence of diabetes on CSCs remains unclear. This study demonstrated that hyperglycemia might promote adipogenesis in CSCs, which induces a decline in myocardial regeneration capability in diabetes.

CSCs were isolated and cultured in high-glucose medium. The levels of β-catenin and TCF-4 in CSCs were determined by immunofluorescence staining and western blot analysis. Adipogenic transcriptional factors and CSCs markers were also examined by flow cytometry and western blot analysis after adipogenesis induction. In addition, Oil Red O staining was performed to investigate lipid droplet formation during adipogenesis induction with or without LiCl, a potent activator of TCF/β-catenin-dependent transcription.

High-glucose conditions inhibited nuclear translocation of β-catenin/TCF-4 and promoted adipogenesis in CSCs. After adipogenesis induction, expression of adipogenic transcriptional factors (PPARγ, ADD1, and C/EBPα) were increased (P < 0.01) and that of CSCs markers (c-Kit, Sca-1, MDR-1, and isl-1) were decreased (P< 0.01) in CSCs in the high-glucose group. Furthermore, lipid droplet formation was increased in CSCs cultured with high glucose, while LiCl attenuated lipid droplet formation in these CSCs (P < 0.01).

These results demonstrated that hyperglycemia inhibited the β-catenin/TCF-4 pathway and promoted CSCs adipogenesis. Our findings suggest a new opportunity for future interventional strategie for abnormal myocardial regeneration and epicardial fat in patients with diabetes.