Advanced glycated end-products affect HIF-transcriptional activity in renal cells

Mol Endocrinol. 2013 Nov;27(11):1918-33. doi: 10.1210/me.2013-1036. Epub 2013 Sep 12.

Abstract

Advanced glycated end-products (AGEs) are ligands of the receptor for AGEs and increase in diabetic disease. MAPK organizer 1 (Morg1) via its binding partner prolyl-hydroxylase domain (PHD)-3 presumably plays a role in the regulation of hypoxia-inducible factor (HIF)-1α and HIF-2α transcriptional activation. The purpose of this study was to analyze the influence of AGEs on Morg1 expression and its correlation to PHD3 activity and HIF-transcriptional activity in various renal cell types. The addition of glycated BSA (AGE-BSA) significantly up-regulated Morg1 mRNA levels in murine mesangial cells and down-regulated it in murine proximal tubular cells and differentiated podocytes. These effects were reversible when the cells were preincubated with a receptor for α-AGE antibody. AGE-BSA treatment induced a relocalization of the Morg1 cellular distribution compared with nonglycated control-BSA. Analysis of PHD3 activity demonstrated an elevated PHD3 enzymatic activity in murine mesangial cells but an inhibition in murine proximal tubular cells and podocytes after the addition of AGE-BSA. HIF-transcriptional activity was also affected by AGE-BSA treatment. Reporter gene assays and EMSAs showed that AGEs regulate HIF- transcriptional activity under nonhypoxic conditions in a cell type-specific manner. In proximal tubular cells, AGE-BSA stimulation elevated mainly HIF-1α transcriptional activity and to a lesser extent HIF-2α. We also detected an increased expression of the HIF-1α and the HIF-2α proteins in kidneys from Morg1 heterozygous (HZ) placebo mice compared with the Morg1 wild-type (WT) placebo-treated mice, and the HIF-1α protein expression in the Morg1 HZ streptozotocin-treated mice was significantly higher than the WT streptozotocin-treated mice. Analysis of isolated mesangial cells from Morg1 HZ (±) and WT mice showed an inhibited PHD3 activity and an increased HIF-transcriptional activity in cells with only one Morg1 allele. These findings are important for a better understanding of the molecular mechanisms of diabetic nephropathy.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adaptor Proteins, Signal Transducing / genetics
  • Adaptor Proteins, Signal Transducing / metabolism
  • Animals
  • Cells, Cultured
  • Diabetes Mellitus, Experimental / metabolism
  • Glycation End Products, Advanced / physiology*
  • Hypoxia-Inducible Factor 1, alpha Subunit / genetics
  • Hypoxia-Inducible Factor 1, alpha Subunit / metabolism*
  • Mice
  • Mice, Inbred C57BL
  • Mice, Transgenic
  • Podocytes / metabolism
  • Procollagen-Proline Dioxygenase / metabolism
  • Receptor for Advanced Glycation End Products
  • Receptors, Immunologic / genetics
  • Receptors, Immunologic / metabolism
  • Serum Albumin, Bovine / physiology
  • Transcription Factors / genetics
  • Transcription Factors / metabolism*
  • Transcription, Genetic*
  • Transcriptional Activation

Substances

  • Adaptor Proteins, Signal Transducing
  • Glycation End Products, Advanced
  • HIF-2 protein, mouse
  • Hif1a protein, mouse
  • Hypoxia-Inducible Factor 1, alpha Subunit
  • MORG1 protein, mouse
  • Receptor for Advanced Glycation End Products
  • Receptors, Immunologic
  • Transcription Factors
  • advanced glycation end products-bovine serum albumin
  • Serum Albumin, Bovine
  • PHD3 protein, mouse
  • Procollagen-Proline Dioxygenase

Grants and funding

This work was supported by a grant from the Deutsche Forschungsgemeinschaft (Wo 460/14-2, 17-1).