Forkhead box A1 induces angiogenesis through activation of the S100A8/p38 MAPK axis in cutaneous wound healing.

BACKGROUND: The association between S100 calcium-binding protein A8 (S100A8) and angiogenesis has been reported in previous reports. This study focuses on the roles of S100A8 in the angiogenesis of human dermal microvascular endothelial cells (HDMECs) and in cutaneous wound healing in mice. METHODS: Candidate genes related to angiogenesis activity were screened using a GSE83582 dataset. The overexpression DNA plasmid of S100A8 was transfected into HDMECs to analyze its effect on cell proliferation, migration, and angiogenesis. Full-thickness skin wounds were induced on mice, followed by adenovirus treatments to analyze the function of gene alteration in wound healing and pathological changes. The upstream regulator of S100A8 was predicted by bioinformatics analysis and verified by luciferase and immunoprecipitation assays. The role of the forkhead box A1 (FOXA1)-S100A8 interaction in p38 MAPK activation and angiogenesis were validated by rescue experiments. RESULTS: S100A8 was identified as a gene significantly correlated with angiogenesis. The S100A8 upregulation promoted the proliferation, migration, and angiogenesis of HDMECs, and it promoted p38 MAPK phosphorylation. Treatment of SB203580, a p38 MAPK inhibitor, blocked the promoting effect of S100A8. FOXA1 was identified as an upstream factor of S100A8 promoting its transcription. FOXA1 overexpression in HDMECs increased p38 MAPK phosphorylation and enhanced the activity of cells, which were blocked by the S100A8 inhibition. Similar results were reproduced in vivo where FOXA1 overexpression accelerated whereas the S100A8 knockdown retarded the cutaneous wound healing in mice. CONCLUSION: FOXA1 mediates the phosphorylation of p38 MAPK through transcription activation of S100A8, thereby inducing angiogenesis and promoting cutaneous wound healing.

Astragaloside IV - mediated endothelial progenitor cell exosomes promote autophagy and inhibit apoptosis in hyperglycemic damaged endothelial cells via miR-21/PTEN axis.

INTRODUCTION: As one of the basic components of Astragalus, Astragaloside IV (AS-IV) has a protective effect on endothelial injury caused by diabetes. AS-IV stimulated endothelial progenitor cells (EPCs) to secrete exosomes loaded with miR-21. This study aimed to investigate the effects of AS-IV-mediated EPCs exosomal miR-21 (EPC-exos-miR-21) on high glucose (HG) damaged endothelial cells. MATERIALS AND METHODS: After the isolation of EPCs derived from fetal umbilical cord blood, exosomes of EPCs were obtained by differential centrifugation. The morphology of exosomes was observed by electron microscopy. The particle size distribution of exosomes was detected by Nanoparticle Tracking Analysis. Human umbilical vein endothelial cells (HUVECs) were treated with 33 mM glucose to establish an HG injury model. Flow cytometry and TUNEL assay were used to characterize the surface markers of primary EPCs and the apoptosis of HUVECs. The gene and protein expression were detected by qPCR, immunofluorescence, and Western blotting. A dual luciferase assay was used to verify the targeting relationship of miR-21 with PTEN. RESULTS: HG environment led to time- and dose-dependent inhibition and enhancement of autophagy and apoptosis in HUVECs. AS-IV stimulated EPCs to secrete exosomes loaded with miR-21. Exosomes secreted by EPCs pretreated with AS-IV [EPC-exo(ASIV)] promoted autophagy and inhibited apoptosis in HG-impaired HUVECs. PTEN is a target of miR-21. MiR-21 carried by EPC-exo(ASIV) repressed PTEN expression in HG-impaired HUVECs. In contrast, p-AKT, p-mTOR, p-PI3K, cleaved PARP and PARP levels were upregulated. Compared to the HG group, the expression of autophagy regulatory genes (ATG5, beclin1 and LC3) was enhanced in the EPC-exo(ASIV) group and EPC-exo(ASIV)-miR-21 mimic group. In contrast, apoptosis-positive regulatory genes (Bax, caspase-3 and caspase-9) were attenuated. Further overexpression of PTEN reversed the expression of these genes. CONCLUSIONS: AS-IV-mediated EPC-exos-miR-21 could enhance autophagy and depress apoptosis in HG-damaged endothelial cells via the miR-21/PTEN axis.

Pro-angiogenic role of ZEB1 in skin wound healing by upregulating VEGFA via microRNA-206 suppression.

Angiogenesis has been identified to assume a critical role in skin wound healing. Moreover, zinc finger E-box binding homeobox 1 (ZEB1) was capable of promoting skin wound healing. Herein, cell and animal experiments were implemented in this study to figure out whether ZEB1 orchestrated angiogenesis during skin wound healing. Subsequent to gain- and loss-of-function approaches in human dermal microvascular endothelial cells (HDMECs), HDMEC proliferation, migration and angiogenesis were evaluated by CCK8, EdU, wound healing, Transwell and angiogenesis in vitro assays. The relationship among ZEB1, microRNA (miR)-206 and vascular endothelial growth factor A (VEGFA) was assessed by microarray analysis, dual-luciferase, ChIP and RIP assays. Finally, the mechanism of ZEB1 in skin wound healing was confirmed by in vivo experiments. Mechanically, ZEB1 upregulation resulted in miR-206 downregulation by binding to miR-206 promoter, and miR-206 repressed VEGFA expression by directly targeting. ZEB1 overexpression enhanced HDMEC proliferation, migration and angiogenesis, which was neutralized by miR-206 upregulation or VEGFA inhibition. Moreover, ZEB1 significantly promoted skin wound healing in mice, which was negated by overexpression of miR-206. Conclusively, ZEB1 augmented angiogenesis to promote skin wound healing by elevating VEGFA expression via miR-206 repression.