Functional analysis of the common haplotype in the receptor for advanced glycation end-products gene previously identified as a susceptibility factor for diabetic nephropathy.

The Receptor for Advanced Glycation End-products (RAGE) belongs to the family of pattern-recognition receptors and is significantly involved in the molecular mechanisms mediating pro-inflammatory action of hyperglycemia in diabetes. The aim of the current study was to elucidate the possible functional impact of the genetic variability in the AGER gene constituting previously identified risk haplotype for diabetic nephropathy (-429C/-374T/2184G) by testing the haplotype-specific effect on the AGER gene transcriptional activity IN VITRO. Promotor and intron 8 constructs carrying respective substitutions were amplified and cloned into pGL3-Basic reporter vector and subsequently used for transfection of HEK293 cells. Following 48hrs incubation in either normo- (5 mM/L) or hyperglycemic (25 mM/L) culture medium luciferase activity was measured to assess transcriptional efficiency. Risk haplotype was associated with the highest transcriptional activity in hyperglycemia and greatest relative increase of activity between normo- and hyperglycemia conditions (approx. 3-times). We conclude that ascertained functional differences in the regulatory regions of the AGER gene might have significant consequences for the development of hyperglycemia-related pathology in diabetics. J. A. Barth Verlag in Georg Thieme Verlag KG Stuttgart. New York.