Effects of novel polymorphisms in the RAGE gene on transcriptional regulation and their association with diabetic retinopathy

Interactions between advanced glycation end products (AGEs) and the recepto r for AGE (RAGE) are implicated in the vascular complications in diabetes. We have identified eight novel polymorphisms, of which the -1420 (GGT)n, -1 393 G/T, -1390 G/T, and -1202 G/A were in the overlapping PBX2 3' untransla ted region (UTR), and the -429 T/C (66.5% TT, 33.5% TC/CC), -407 to -345 de letion (99% I, 1% I/D, 0% D), -374 T/A (66.4% TT, 33.6% TA/AA), and +20 TIA were in the RAGE promoter. To evaluate the effects on transcriptional acti vity, me measured chloramphenicol acetyl transferase (CAT) reporter gene ex pression, driven by variants of the -738 to +49 RAGE gene fragment containi ng the four polymorphisms identified close to the transcriptional start sit e. The -429 C, -374 A, and 63-bp deletion alleles resulted in a mean increa se of CAT expression of twofold (P < 0.0001), threefold (P < 0.001), and fo urfold (P < 0.05), respectively, with the -374 T and A alleles yielding hig hly differential binding of nuclear protein extract from both monocyte- and hepatocyte-derived cell lines. The prevalence of the functional polymorphi sms were investigated in subjects with type 2 diabetes (106 with and 109 wi thout retinopathy), with the -429 C allele showing an increase in the retin opathy group (P < 0.05). These data suggest that the polymorphisms involved in differences in RAGE gene regulation may influence the pathogenesis of d iabetic vascular complications.