The vascular endothelium is key target for immune, and thrombotic responses that has to be controlled in successful xenotransplantation. Several genes were identified that if induced or overexpressed help to regulate the inflammatory response and preserve the transplanted organ function and metabolism. However, few studies addressed combined expression of such genes. The aim of this work was to evaluate in vivo the effects of the simultaneous expression of a three human genes in a mouse generated using the multi-cistronic F2A technology. Male 3-month-old mice that express human heme oxygenase 1 (hHO-1), ecto-5’-nucleotidase (hE5NT), and ecto-nucleoside triphosphate diphosphohydrolase 1 (hENTPD1) (Transgenic) were compared to wild-type FVB mice (Control). Background analysis include extracellular nucleotide catabolism enzymes profile on the aortic surface, blood nucleotide concentration and serum L-arginine metabolites. Furthermore, inflammatory stress induced by LPS in transgenic and control mice was used to characterize interleukin 6 (IL-6) and adhesion molecules endothelium permeabil-ity responses. Transgenic mice had significantly higher rates of extracellular adenosine triphosphate and adenosine monophosphate hydrolysis on the aortic surface in comparison to control. Increased levels of blood AMP and adenosine were also noticed in transgenics. Moreover, transgenic ani-mals demonstrated the decrease in serum monomethyl-L-arginine level and a higher L-arginine/ monomethyl-L-arginine ratio. Importantly, significantly decreased serum IL-6, and adhesion mol-ecule levels were observed in transgenic mice in comparison to control after LPS treatment. Fur-thermore, reduced endothelial permeability in the LPS-treated transgenic mice was noted as com-pared to LPS-treated control. The human enzymes (hHO-1, hE5NT, hENTPD1) simultaneously encoded in transgenic mice demonstrated benefits in sev-eral biochemical and functional aspects of endothelium. This is consistent in use of this approach in the context of xenotransplantation.

The vacuolar proton translocating ATPase (V-ATPase) is a transmembrane multi-protein complex fundamental in maintaining a normal intracellular pH. In the tumoral contest, its role is crucial since the metabolism is mainly based on anaerobic glycolytic reactions. Moreover, the neoplastic cells use the V-ATPase to extrude chemotherapy drugs to the extra-cellular compartment, as a drug-resistance mechanism. In glioblastoma (GBM), the most malignant and incurable primary brain tumor, the expression of this pump is upregulated, making it a new possible therapeutic target. In this work, the bafilomycin A1 induced-inhibition of V-ATPase in patients-derived glioma stem cell (GSC) lines was evaluated together with temozolomide, the first-line line therapy against GBM. In contrast with previous published data, the proposed treatment did not overcome the resistance to the standard therapy. In addition, our data showed that nanomolar dosages of bafilomycin A1 lead to the blockage of the autophagy process and cellular necrosis, making the drug unusable in models that are more complex. Nevertheless, the increased expression of V-ATPase following bafilomycin A1 suggests a critical role of the proton pump in GBM stem component, encouraging the search for novel strategies to limit its activity in order to get around the resistance to the conventional therapy.