Abstract
Background: Glucocorticoid could induce injury and apoptosis of bone microvascular endothelial cells (BMECs) in the femoral head and the application of icariin showed a protective effect. However, the impact of autocrine exosomes during these processes is still to be confirmed.Methods: Exosomes were extracted from BMECs treated with hydrocortisone or hydrocortisone plus icariin by super-speed centrifugation; exosome-carried proteins were evaluated via BCA assay, Western blotting, protein array assay and Elisa test, while miRNA expression profile was assessed via high-throughput sequencing and confirmed by quantitative polymerase chain reaction (qPCR) to screen candidate molecules responsible for BMEC-Exo function. BMECs were incubated with and without exosomes before glucocorticoid intervention and then the impact of BMECs-derived exosomes on BMECs viability, apoptosis, migration, angiogenesis, and protein expression was further assessed by a series of functional assays. Results: Exosomes secreted by BMECs could ameliorate glucocorticoid-induced endothelial cellular injury, improve cell viability, decrease cell apoptosis, and promote cell migration and angiogenesis compared with the blank control. These effects of secreted exosomes could be reinforced by icariin intervention. Meanwhile, mechanism studies showed that expression level of eNOS, COX-2, and pERK were significantly increased while the cleaved caspase-3 level was decreased in BMECs after coculture with exosomes. Although icariin treatment would not significantly change the size and total protein content of BMECs-derived exosomes, expression of exosome-carried vascular endothelial growth factor (VEGF) and transforming growth factor β1 (TGF-β1) was enhanced and numerous miRNAs involved in cell proliferation and apoptosis were up-regulated (e.g., hsa-miR-1469 and hsa-miR-133a-5p) or down-regulated (e.g., hsa-miR-10b-5p) (p < 0.05). 29 differentially expressed inflammatory factors were detected between the exosomes secreted by the Icariin-treated and the Model groups.Conclusion: To sum up, the present study indicates that autocrine exosomes could significantly improve glucocorticoid-induced injury of BMECs, partially mediated by activation of MAPK/ERK pathway and regulation of several inflammation/apoptosis/proliferation-associated proteins. Icariin intervention could reinforce these effects and may act as a promising drug for improving glucocorticoid-induced injury of BMECs. In vivo or animal studies are still required to better understand the function of BMEC-derived exosomes.
Hepatocyte Growth Factor is a Regulator in the Proliferation of Microvascular Endothelial Cells in Bovine Corpus Luteum
