Endothelial cells from human umbilical vein inhibit generation of monocyte-derived dendritic cells

This study was aimed to investigate the effect of human umbilical vein endothelial cells (HUVEC) on dendritic cell (DC) development. First, HUVEC were isolated from human umbilical cord by collagenase digestion, and then the morphology, immunophenotypes and functions were identified. Furthermore, the HUVEC were cocultured with CD14(+) monocytes under the cytokine condition for detecting the influence of HUVEC on differentiation of CD14(+) cells to DC. The phenotype of dendritic cells derived from CD14(+) cells was analyzed by flow cytometry, the immunoregulatory function of DC was tested by mixed lymphocyte reaction (MLR). The change of IL-6 and VEGF as well as EPK and p38 signal pathway were analyzed by neutral antibody experiment and Western blot. The results showed that HUVEC isolated from human umbilical cord were characterized by spindle-shaped morphology, homogenous immunophenotypes (vWF(+)CD31(+)CD73(+)CD45(-)HLA-DR(-)CD86(-)CD34(low)), Dil-Ac-LDL incorporation ability and forming capillary-like structures. Following stimulation with granulocyte-macrophage colony-stimulating factor (GM-CSF) plus interleukin-4 (IL-4), HUVEC cocultures could inhibit the initial differentiation of CD14(+) monocyte to DC. Interestingly, IL-6 and VEGF enhanced the suppression effect of HUVEC on generation of DC via activation of the ERK or p38 mitogen activated protein kinase pathway. It is concluded that HUVEC are involved in DC development and can suppress the differentiation of monocyte to DC.