Interleukin-10 overexpression improves the function of endothelial progenitor cells stimulated with TNF-α through the activation of the STAT3 signaling pathway

Lentivirus vector-interleukin-10 green fluorescent protein (LV-IL-10-GFP) was transfected into endothelial progenitor cells (EPCs) in the present study. The aim was to detect the function of IL-10-modified EPCs and analyze the molecular mechanism. EPCs were cultured and identified by fluorescent labeling with the von Willebrand factor antibody, vascular endothelial growth factor (VEGF) receptor, Ulex europaeus agglutinin-1 and acetylated low-density lipoprotein. Subsequently, EPCs were transfected with LV-IL-10-GFP and lentivirus vector-noncontain-GFP as the control group. Enzyme-linked immunosorbent assay (ELISA) was used to detect the concentrations of cytokines in the supernatant with or without tumor necrosis factor-alpha (TNF-alpha). All types of cells were assessed by a tube formation assay, adhesion assay and migration assay induced with or without TNF-alpha. Cell cycle was assessed by flow cytometry. Western blot analysis was applied to detect the expression of proteins in the cells. ELISA analysis showed that the levels of TNF-alpha and IL-8 in the supernatant without TNF-alpha significantly decreased in EPC-LV-IL-10-GFP (P<0.05 for all). By contrast, the levels of IL-10 and VEGF were contrasting in association with these. The concentrations of cytokines in the supernatant with TNF-alpha were consistent to the supernatant without TNF-alpha. There was no statistically significant difference in the average number of EPCs undergoing migration, adhesion, total length and cell growth among the EPC, EPC-LV-IL-10-GFP and EPC-LV-NC-GFP groups without TNF-alpha. Further study showed that EPC-LV-IL-10-GFP with TNF-alpha significantly enhanced EPC migration, adhesion and promoted tube formation (P<0.05 for all). Western blot analysis revealed that the expression of VEGF, matrix metallopeptidase-9 and phosphorylated-signal transducer and activator of transcription 3 (p-STAT3) significantly increased in the EPC-LV-IL-10-GFP group. Conversely, STAT-3 expression decreased in the EPC-LV-IL-10-GFP group. The present study suggested that overexpression of IL-10 had no effect on migration, adhesion, tubule formation and cell growth of EPCs without TNF-alpha. Furthermore, in EPCs stimulated with TNF-alpha, the overexpression of IL-10 improved EPC function, including migration, adhesion and tubule formation by activating the STAT3 signal pathway.