Diabetologie und Stoffwechsel 2006; 1 - A114
DOI: 10.1055/s-2006-943839

RAGE modulates neuronal glyoxalase-1 transcription, expression and activity

SB Stoyanov 1, GM Haag 1, I Konrade 1, IK Lukic 1, P Humpert 1, P Thornalley 2, SR Thorpe 3, PP Nawroth 1, A Bierhaus 1
  • 1University of Heidelberg, Department of Medicine I, Heidelberg, Germany
  • 2University of Essex, Department of Biological Sciences, Essex, United Kingdom
  • 3Medical University of South Carolina, Department of Chemistry and Biochemistry, South Carolina, United States of America

Introduction: Methylglyoxal (MG) is a precursor of a variety of advanced glycation endproducts (AGEs), which are supposed to contribute to the development of late diabetic complications via interaction with their cellular receptor RAGE. MG and other AGE-precursors are detoxified by the glyoxalase-system.

Aim: We study expression of the AGE-detoxifying enzyme glyoxalase-1 (GO-1) in peripheral nerves and dorsal root ganglia (DRG) of healthy and diabetic wildtype (WT)- and RAGE-/– mice to determine the interaction of RAGE and GO-1.

Methods: GO1 transcription (Real time PCR), -expression (Western Blot and IHC) and -activity (Enzyme assay) was determined in various cell cultures including dorsal root ganglia (DRG) and sciatic nerves from WT- and RAGE-/–mice. Neuronal blood flow was measured in sciatic nerves by Laser Doppler blood perfusion method and pain perception was analysed by Hot Plate and Tail flick assays.

Results: Transcription, expression and activity of GO1 were significantly higher in peripheral nerves of healthy RAGE-/–mice when compared to WT-mice. Diabetes reduced GO1 transcription in WT-mice, while, the decrease was less prominent in RAGE-/–mice. Cell culture experiments using DRG isolated from WT and RAGE-/–mice also demonstrated a higher basal GO1 expression in the absence of RAGE. However, GO1 expression was increased in WT cells treated with the RAGE antagonist sRAGE for 48h indicating that inhibition or absence of RAGE improves GO1. Incubation with RAGE-ligands reduced GO1 in WT-, but not RAGE-/–DRG, further implying that engagement of RAGE directly suppresses GO1. The functional significance of GO1 for DN was studied in WT and RAGE-/–mice, kept in the diabetic state for 4 months in the presence or absence of GO1-inhibitors. GO1-inhibitors impaired neuronal blood flow in WT and RAGE-/–mice and increased pain perception in early diabetes in both, WT- and RAGE-/–mice.

Conclusion: Diabetes dependent reduction in GO1, contributes to functional deficits in DN and strongly indicate that GO1-gene is under control of RAGE-dependent signalling.