Extracellular vesicles as masters of endothelial plasticity: bridging the gap between health and disease

Chronic non-communicable diseases contribute to over 70% of global deaths, and vascular alterations play a pivotal role in development and severity of these. Cells communicate in multiple ways, including secretion of extracellular vesicles (EVs). EVs transport regulatory factors that can alter the phenotype of target cells. This thesis focuses on the impact of pathological cancer cell-derived EVs (CA-EVs) on angiogenesis, contrasting with the pro-angiogenic capacity of therapeutical adipose tissue-derived stem cell-EVs (ASCs-EVs). We investigated the EV components influencing angiogenesis, the effect of hypoxia on EV's characteristics, composition, and function; and the extracellular matrix (ECM) influence in the EV effect. Both CA-EVs and ASCs-EVs promoted sprouting angiogenesis, stabilized the sprouts and displayed differential effects in response to ECM stiffness. Hypoxia i) induced high enrichment in the already pro-angiogenic proteome of CA-EVs, ii) increased EV rigidity, proteins related to membrane rigidity, and endothelial EV uptake, and iii) increased EV enrichment of molecules associated with the angio-metabolic switch activation and tip cell phenotype. In contrast, hypoxia did not greatly influence the EVs-miRNAome. We described a set of angiogenesis regulators and tested the pro-angiogenic effect of miR23b-3p. CA-EVs and ASCs-EVs shared ∼75-94% of their miRNAome, and more than 80% of it was represented in 10 shared families/clusters. We identified redundant co-regulatory cross-talkers in angiogenesis activation and emphasized the need for a holistic understanding of EV biology beyond individual molecules. Results suggest a potent regulatory role of EVs in fine-tuning paracrine signaling. Pathological and therapeutical EVs might be on the same side of the river and may not need a bridge in terms of angiogenesis (largely overlapping). However, other influences were not studied, and further research is needed for effective EV-based therapy.