Adenoviral infection or deferoxamine? Two approaches to overexpress VEGF in β-cell lines

Abstract

Rapid and adequate revascularization of transplanted islets is important for their survival and function during transplantation. Vascular endothelial growth factor (VEGF) could play a critical role with respect to islet revascularization. The aim of this study was to compare two strategies that are used to overexpress VEGF in beta-cells: (1) gene therapy through adenoviral infection and (2) a pharmacological approach using deferoxamine (DFO). beta-Cell lines from rat insulinoma (RINm5F) were either infected using an adenovirus encoding the gene of human VEGF 165 or incubated with DFO. One day after treatment, the viability of RINm5F cells was preserved with 10 micromol/L of DFO (103.95 +/- 5.66% toward control; n = 4). In addition, adenoviral infection maintained the viability of cells for all the concentrations used. In both treatments, overexpression of VEGF was in a comparable level. Finally, the ratio of Bax/Bcl-2 indicated that the apoptosis increased in infected beta-cells whereas treatment with DFO seems to be antiapoptotic. Our results suggest that the use of DFO could be a realistic approach to improve the vascularization of islets during transplantation.

Early Effects of Liver Regeneration on Endocrine Pancreas: In Vivo Change in Islet Morphology and In Vitro Assessment of Systemic Effects on β-Cell Function and Viability in the Rat Model of Two-Thirds Hepatectomy

“…Although HGF is known to be a β-cell protector factor [29], the similar serum HGF levels found 3 days after two-thirds hepatectomy in our study did not support the role of HGF in the maintained RIN-m5F viability. In vitro, VEGF improves RIN-m5F viability [30]. In our study, a trend to the increased VEGF serum concentrations suggest that VEGF secretion following two-thirds hepatectomy would partly impact liver regeneration.…”

In Vitro and In Vivo Investigation of the Angiogenic Effects of Liraglutide during Islet Transplantation

“…Western blotting was performed as described previously [ 16 ] using the appropriate primary and secondary antibodies: anti-rat HIF-1α mouse monoclonal antibody (R&D Systems, Minneapolis, USA; 1/1000); anti-rat mTOR and phosphorylated mTOR (Ser2448) rabbit polyclonal antibodies (Cell Signalling, Ozyme, St Quentin Yvelines, France; 1/500); anti-mouse goat peroxidase (HRP)-conjugated and anti-rabbit goat peroxidase (HRP)-conjugated antibodies (Sigma-Aldrich, St Louis, MO, USA; 1/8000). Proteins were visualized with the Luminata ™ Forte Western HRP Substrate (Millipore) and detected using enhanced chemilumiscence (Bio-Rad).…”

“…Thus, a pharmacological approach to increase VEGF expression may be more suitable for clinical application. We previously reported that pre-treatment of pancreatic islets with deferoxamine, an iron chelator already in clinical use, induced VEGF overexpression by activating the hypoxia inducible factor-1α (HIF-1α) pathway; this approach improved metabolic control in diabetic rats [ 14 ], [ 16 ]. However, long-term maintenance of graft function was not achieved, probably due to the stabilisation of HIF-1α, which triggers apoptosis at high concentrations [ 17 ].…”

Endurance training stimulates growth and survival pathways and the redox balance in rat pancreatic islets

“…The activation of ERK1/2 seems to be involved with the increase of Bcl2 mRNA and protein content, as well as the inactivation of caspase-3, mediated by an enhanced CREB expression (11). In islets from TRE5ϫ rats, we also found a significant decrease in the Bax/Bcl-2 ratio, a well known predictor of ␤-cell survival (20,25). This observation agrees with the previous description of reduced ␤-cell apoptosis in islets from trained rats (8) and provides evidence that endurance training improves ␤-cell survival through the activation of the AKT and ERK1/2 signaling pathways.…”