TGF-β1 enhanced myocardial differentiation through inhibition of the Wnt/β-catenin pathway with rat BMSCs

Research Progress on Cardiac Tissue Construction of Mesenchymal Stem Cells for Myocardial Infarction

Heart failure is still the main complication affecting the prognosis of acute myocardial infarction (AMI), and mesenchymal stem cells (MSCs) are an effective treatment to replace necrotic myocardium and improve cardiac functioning. However, the transplant survival rate of MSCs still presents challenges. In this review, the biological characteristics of MSCs, the progress of mechanism research in the treatment of myocardial infarction, and the advances in improving the transplant survival rate of MSCs in the replacement of necrotic myocardial infarction are systematically described. From a basic to advanced clinical research, MSC transplants have evolved from a pure injection, an exosome injection, the genetic modification of MSCs prior to injection to the cardiac tissue engineering of MSC patch grafting. This study shows that MSCs have wide clinical applications in the treatment of AMI, suggesting improved myocardial tissue creation. A broader clinical application prospect will be explored and developed to improve the survival rate of MSC transplants and myocardial vascularization.

The effects of β-catenin on cardiomyogenesis via Islet-1 and MLIP ubiquitination

Mesenchymal stem cells (MSCs) can treat myocardial injury-related diseases by differentiating into cardiomyocytes. Islet-1 plays an essential role in cardiac maturation. We have discovered that Islet-1 plays a crucial role in the histone acetylation regulation in this process. In addition, to increase GATA4/Nkx2.5 expression, Islet-1 may bind to Gcn5 and then guide Gcn5 to the GATA4/Nkx2.5 promoters, thereby facilitating the differentiation of MSCs into cardiomyocytes. Islet-1 is an important factor in the maturation of the heart. We have previously found that the pivotal factor in histone acetylation regulation in this process is Islet-1. Furthermore, Islet-1 and Gcn5 may boost GATA4/Nkx2.5 expression, which in turn promotes cardiomyocyte differentiation from MSCs. But the molecular mechanism of Islet-1 binding to GCN5 has not been elucidated. In this study, we found that the competitive binding relationship between Islet-1 and MLIP and GCN5 affected myocardial differentiation. The key enzymes of ubiquitination modification of MLIP and Islet-1 are UBE3C and WWP1, respectively. When short hairpin RNA (shRNA) was used to inhibit β-catenin expression, we found that the expression of UBE3C was upregulated, modifying MLIP ubiquitination and reducing its expression, and it upregulated Islet-1 by inhibiting the expression of WWP1. By using the chromatin immunoprecipitation (ChIP) and luciferase reporter system, we found that when MLIP binds to Islet-1, it significantly inhibits the transcriptional activity of Islet-1. In summary, our results show that decreasing β-catenin regulates the ubiquitination of Islet-1 and MLIP, affecting their expression, reducing the amount of Islet-1 binding to MLIP, and increasing the amount of binding to GCN5 in the nucleus. Therefore, the transcriptional activity of Islet-1 is significantly activated, inducing C3H10T1/2 cells to differentiate into myocytes. Further knowledge of biochemical pathways, including molecular signaling pathways, can provide more insights into the myocardial differentiation mechanism of MSCs.

Tangshen Formula Improves Diabetes-Associated Myocardial Fibrosis by Inhibiting TGF-β/Smads and Wnt/β-Catenin Pathways

Cardiovascular disease has become the main cause of death among complications of diabetes. Myocardial fibrosis is a crucial pathological change of cardiovascular disease. Tangshen Formula (TSF) shows a good clinical effect in the treatment of diabetic kidney disease (DKD). However, whether TSF alleviates diabetes-associated myocardial fibrosis is still unknown. In the present research, we studied the effect and mechanism of TSF in the treatment of myocardial fibrosis in vivo and in vitro. We found that TSF treatment significantly downregulates myocardial fibrosis-related markers, including collagens I and III, and α-SMA. TSF also protects primary mouse cardiac fibroblast (CF) from transforming growth factor-β1- (TGF-β1-) induced damage. Moreover, TSF decreased the expression levels of TGF-β/Smad-related genes (α-SMA, collagens I and III, TGF-β1, and pSmad2/3), and increased Smad7 gene expression. Finally, TSF decreased the expressions of wnt1, active-β-catenin, FN, and MMP7 to regulate the Wnt/β-catenin pathway. Taken together, TSF seems to attenuate myocardial fibrosis in KKAy mice by inhibiting TGF-β/Smad2/3 and Wnt/β-catenin signaling pathways.