HOCI Probe CPP Induces the Differentiation of Human Dermal Fibroblasts into Vascular Endothelial Cells through PHD2/HIF-1α/HEY1 Signaling Pathway

Human dermal fibroblasts (HDFs) have the potential to differentiate into endothelial cells (VECs). In our previous research, we reported that a hypochlorous acid (HOCI) probe CPP efficiently induced the differentiation of HDFs into VECs, however, the mechanism of differentiation was not clear. As an HOCI probe, CPP binds HOCI to modulate its effects. In this study, through Western blotting, qPCR, and PHD2 enzyme activity assay, we found that CPP inhibited the enzyme activity of prolyl-4-hydroxylase 2 (PHD2), thereby stabilizing HIF-1 alpha. To further clarify the mechanism by which CPP inhibits PHD2 enzyme activity, we constructed plasmids, and found that CPP inhibited PHD2 activity to increase the HIF-1 alpha level through the modulation of PHD2 at Cys302 by HOCI in HDFs. Furthermore, RNA-seq experiments showed that CPP could induce the expression of HEY1, which is not only a target gene regulated by HIF1 alpha, but also a key transcription factor for VECs. We used siRNA transfection and in vivo experiments to confirm that CPP could induce HDFs to differentiate into VECs by HEY1. In summary, we identified a new inhibitor of PHD2, demonstrated the new role of HOCI in cell differentiation, and elucidated the mechanism by which HOCI probe CPP induced the differentiation of HDFs into VECs.

Automated summary

In this study, we identified a new inhibitor of PHD2 and demonstrated the new role of HOCI in cell differentiation. Moreover, we elucidated the mechanism by which the HOCI probe CPP induced the differentiation of HDFs into VECs.