Salvianolic Acid B Facilitates Endothelial Differentiation of Human Induced Pluripotent Stem Cells via Piezo1/MEK/Erk

Abstract

Background: Piezo1 is a mechanosensitive Ca²⁺ channel protein that participates in stem cells fate. Salvianolic acid B (Sal-B) is a polyphenolic compound that promotes endothelial differentiation. This study aims to assess the role of Sal-B in facilitating endothelial differentiation by regulating the activity of Piezo1. Methods: The system of human-induced pluripotent stem cells (iPSCs) differentiating into endothelial cells (ECs) in vitro was established to study the role and underlying mechanism of Piezo1 and Sal-B in the regulation of endotheliogenesis. Human iPSCs were divided into four groups, including the normal Sal-B shPiezo1, shPiezo1+Sal-B, shNT and shNT+Sal-B. Fura2-AM was used to record intracellular calcium ion changes. The relative mRNA levels of Piezo1, CD144, endothelial Nitric Oxide Synthase (eNOS), mitogen-activated protein kinase (MAPK) kinase (MEK) and extracellular signal-regulated kinase1/2 (Erk1/2) were identified by Quantitative Reverse Transcription-Polymerase Chain Reaction (RT-qPCR) while the protein levels were measured by Western blotting (WB). Results: The addition of 50 μM Sal-B significantly increased the differentiation of ECs. WB and RT-qPCR results showed that Sal-B increased the relative levels of eNOS mRNA, CD144 mRNA, CD144 protein and the tube formation in vitro. Sal-B treatment enhanced Piezo1 expression and Yoda1 activated Ca²⁺ influx, and amplified MEK/Erk1/2 phosphorylation of endothelial cells (ECs) derived from iPSCs (iPSC-ECs). Silencing of Piezo1 impeded the effect of Sal-B on increasing the rate of endotheliogenesis, as well as the MEK/Erk1/2 phosphorylation of iPSC-ECs. Conclusions: The results indicate that Sal-B promotes endothelial differentiation of iPSCs through Piezo1 by triggering the internal flow of Ca²⁺ and thus further amplifying MAPK/Erk1/2 signaling. Here, we found that Sal-B allows the increase in the number and quality of ECs differentiated from iPSCs. These in-vitro studies constitute a starting point for the future use of this compound in regenerative medicine.