Identification of a new way to induce differentiation of dermal fibroblasts into vascular endothelial cells.

BACKGROUND: Human dermal fibroblasts (HDFs) have the potential to differentiate into vascular endothelial cells (VECs), but their differentiation rate is low and the mechanism involved is not clear. The small molecule pathway controls the phenotype of fibroblasts by activating cellular signaling pathways, which is a more convenient method in the differentiation strategy of HDFs into VECs. METHODS: In this study, HDFs were treated with the different doses of CPP ((E)-4-(4-(4-(7-(diethylamino)-2-oxo-2H-chromene-3-carbonyl) piperazin-1-yl) styryl)-1-methylpyridin-1-ium iodide), and the mRNA and protein levels of HDFs were detected by qPCR, Western blot, flow cytometry and immunofluorescent staining. The matrigel assays, acetylated-LDL uptake and angiogenesis assays of chick embryo chorioallantoic membrane (CAM) and hindlimb ischemia model of nude mice were performed to evaluate the functions of VECs derived from HDFs. RESULTS: Here, we report that the small chemical molecule, CPP, can effectively induce HDFs to differentiate into VECs. First, we observed the morphological changes of HDFS treated with CPP. Flow cytometry, Western blot and qRT-PCR analyses showed that CPP effectively decreased the level of the HDFs-marker Vimentin and increased levels of the VEC-markers CD31, CD133, TEK, ERG, vWF, KDR and CDH5. Detection of the percentage of CD31-positive cells by immunofluorescent staining confirmed that CPP can effectively induce HDFs to differentiate into VECs. The results of Matrigel assays, DiI-ac-LDL uptake, angiogenesis assays on CAM and hindlimb ischemia model of nude mice showed that CPP-induced HDFs have the functions of VECs in vitro and in vivo. Western blot and qRT-PCR analysis showed that CPP induces HDFs to differentiate into VECs by promoting the expression of pro-angiogenic factors (VEGF, FGF-2 and PDGF-BB). CONCLUSIONS: Our data suggest that the small chemical molecule CPP efficiently induces the differentiation of HDFs into VECs. Simultaneously, this new inducer provides a potential to develop new approaches to restore vascular function for the treatment of ischemic vascular diseases.

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 (HOCl) 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-1α. 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-1α level through the modulation of PHD2 at Cys302 by HOCl in HDFs. Furthermore, RNA-seq experiments showed that CPP could induce the expression of HEY1, which is not only a target gene regulated by HIF1α, 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 HOCl in cell differentiation, and elucidated the mechanism by which HOCl probe CPP induced the differentiation of HDFs into VECs.

Grp94 Inhibitor HCP1 Inhibits Human Dermal Fibroblast Senescence.

Researchers are paying more and more attention to aging, especially skin aging. Therefore, it is urgent to find an effective way to inhibit aging. Here, we report a small chemical molecule, HCP1, that inhibited the senescence of human dermal fibroblasts (HDFs). First, we performed morphological experiment and found that HCP1-treated HDFs were no longer elongated and flat compared to DMSO-treated groups. Next, we found that the number of ß-gal positive cells decreased compared to DMSO-treated groups. Through flow cytometry, western blot, and immunofluorescence, we found that HCP1 could inhibit the senescence of HDFs. In the study of the mechanism, we found that HCP1 could regulate the AMPK/mTOR signal pathway through glucose-regulated protein 94 (Grp94). In addition, we found that HCP1 could promote the interaction between Grp94 and lysosomes, which led to an increase in the activity of lysosomes and inhibited the senescence of HDFs. At the same time, we found that HCP1 decreased the concentration of Ca2+ in mitochondria, inhibiting the senescence of HCP1. Therefore, we propose that HCP1 is a potential aging-inhibiting compound, and provide a new idea for the development of senescence-inhibiting drugs.