Dendritic cell-endothelial cell cross-talk in angiogenesis.

Dendritic cells (DCs) are professional antigen-presenting cells that have a pivotal role in the onset and regulation of adaptive immune responses. DCs have the ability to regulate inflammation through their capacity to release cytokines and chemokines and kill pathogens, which they share with other phagocytes. Recent observations have shown that different DC subsets produce and release various pro- and anti-angiogenic mediators depending on their activation status and cytokine milieu. In particular, alternatively activated DCs exert a potent pro-angiogenic activity that is mediated by the prototypic angiogenic growth factor vascular endothelial growth factor-A (VEGF-A). In turn, pro- and anti-angiogenic mediators can affect the biology of DCs, modulating their differentiation and maturation. Finally, DCs can trans-differentiate into endothelial-like cells, possibly contributing to vasculogenesis in the adult. Thus, DCs might exert an important impact on the neovascularization process in different physiopathological conditions.