42nd FEBS Congress, From Molecules to Cells and Back, Jerusalem, Israel, September 10-14, 2017

The vessel wall has been reported as a reservoir for different types of vascular stem cells, particularly the mural layers of postnatal vessels contain the multipotent mesenchymogenic population. Increasing evidences suggest that the secretome of stem cells is able to modulate response of resident cells, including endothelial cells, in the pathogenesis of different diseases. Considering the pig an excellent model for translational medicine, we recently isolated and characterized a population of MSC-like cells from porcine aorta, named porcine Aortic Vascular Precursor Cells (pAVPCs) with pericyte-like properties. The aim of the present research was to investigate the ability of pro-inflammatory lipopolysaccharide (LPS) to influence pAVPCs secretome, furthermore the effects of secretome on LPS-induced endothelial cell death was tested. pAVPCs were seeded in a 24 well plate and treated with LPS (10 or 0,1 μg/ml) for 4 hours. A preliminary screening on inflammatory pathway was performed on cells by an RT2 Profiler PCR Arrays (84 genes) and on culture media by Luminex Multiplex Elisa Assays (13 cytokines and chemokines). A significant increase of cytokines (TNF-α, IL-1α, IL1-β, IL-6 and IL-8) and chemokines (CXCL2, CXCL10, CCL1, CCL20, CSF-2) mRNA was detected even with a different degree of intensity. At protein level multiparametric Elisa confirmed a significant increase of IL-6 and IL-8, while IL-1α, IL-2, IL-4, IL-10, IL-18, CSF-2, IFN-γ decreased; TNF- α and IL1- β has never been detectable. Then, conditioned media of pAVPCs were added to LPS-treated endothelial cells and showed a clear protective action against LPS cytotoxicity evaluated by MTT test. Overall, our results indicated that pAVPCs strongly responded to LPS and their conditioned medium is able to protect endothelial cells against pro-inflammatory stimulus.