PB0164 - Anti-inflammatory effect of archaeolipid nanovesicles on human endothelial cells

Background: New generation of liposomes called nanoarchaeosomes (ARC) are nanovesicles (NVs) made of archaeolipids employed as drug delivery systems that exhibit high structural stability. So far there are no reports on the effects of ARC on human vascular endothelium, data crucial for their eventual clinical use.

Aims: The present study investigated the effects of ARC on human umbilical vein endothelial cells (HUVEC) in physiological conditions and under inflammatory conditions and compared it with conventional liposomes (LIP).

Methods: HUVEC were non-stimulated or stimulated with LPS, Pam3CSK4, E. coli, TNF-α or IL-1β in the absence or presence of nanovesicles. We analyzed cell viability and apoptosis (acridine orange/ethidium bromide), cell proliferation (EdU assay), expression of ICAM-1 and E-selectin (cytometry), secretion of IL-6 and von Willebrand Factor (vWF) (ELISA), mRNA expression of ICAM-1 and vWF (RT-qPCR), uptake of NVs (cytometry and confocal microscopy) and signaling pathways (cytometry and western blot). Results were analyzed by ANOVA followed by Bonferroni test (p < 0.05, n=4-6).

Results: None of the NVs affected the viability, cell proliferation and expression of ICAM-1 and E-selectin under basal conditions, but ARC reduced the expression of both molecules and the secretion of IL-6 induced by LPS, Pam3CSK4 or E.coli, an effect not observed with TNF-α or IL-1 beta (Figure 1). Interestingly, ARC significantly decreased basal vWF levels and those induced by all stimuli (Figure 1). None of these parameters were modified by the liposomes. Only ARC were endocytosed by HUVEC and reduced mRNA expression of ICAM-1 and vWF via NF-kB and ERK1/2 in LPS-stimulated endothelial cells (Figure 2).

Conclusion(s): This is the first report on the anti-inflammatory and anti-thrombotic effect of ARC on endothelial cells. Loaded with anti-inflammatory drugs, ARC could magnify their activity on inflamed endothelium, and therefore their research in vasculopathies is of special interest.