Chronic resveratrol treatment reduces the pro-angiogenic effect of human fibroblast "Senescent Associated Secretory Phenotype" (SASP) on endothelial colony forming cells: the role of IL8

Senescent cells are characterized by an increased secretion of inflammatory and growth factors, known as the "senescence-associated secretory phenotype" (SASP), producing a pro-tumoral and pro-angiogenic microenvironment. The present work proposes chronic resveratrol treatment (5 µM for 5 weeks, termed R5) of senescent MRC5 fibroblasts as a mean to mimic and target the angiogenic trait of stromal fibroblast SASP. Senescent fibroblast conditioned medium (CM sen) was effective in enhancing the angiogenic properties of endothelial colony forming cells (ECFC), i.e. invasive activity and capillary morphogenesis capability in vitro, that were significantly reduced when CM were collected after resveratrol pre-treatment (CM senR5). The attenuation of ECFC angiogenic phenotype induced by CM senR5 was accompanied by reduced protein levels of epidermal growth factor and urokinase plasminogen activator receptors (EGFR, uPAR), and by a related decreased activation of receptor-tyrosine-kinase (RTK)-signaling pathways. IL8 levels were found reduced in CM senR5 compared to CM sen, with the associated reduction of IL8/CXCR2 binding in ECFCs. IL8-subtraction mitigated the pro-angiogenic features of CM sen and the associated intracellular signaling in ECFCs, indicating a prominent role of IL8 in the pro-angiogenic effects of CM sen. IL8 modulation is an important mechanism underlying the anti-angiogenic activity of resveratrol on MRC5 SASP.