Adenosine A2B receptor mediates an increase on VEGF-A production in rat kidney glomeruli

Up-regulation of the glomerular expression and the activity of vascular endothelial growth factor-A (VEGF) have been identified as an early pathogenic event for the progression of diabetic nephropathy. Currently, however the mediators are not yet clearly recognized. In this study we identified all four adenosine receptor (AR) subtypes, i.e. A1, A2A, A2B and A3 in isolated rat kidney glomeruli. We localized the expression of A2BAR in podocytes, the primary VEGF producing cells. The ex vivo treatment of kidney glomeruli with adenosine or a general AR agonist NECA, increases VEGF protein content. In addition, NECA treatment elicits VEGF release. These effects were blocked by the A2BAR selective antagonist MRS1754 supplementation. Furthermore, we showed that A2BAR activation was necessary to promote a higher expression of VEGF in kidney glomeruli upon exposure to high d-glucose concentration, a pathogenic condition like those observed in diabetic nephropathy.