Advanced glycation end-products suppress neuropilin-1 expression in podocytes

Kidney Int. 2009 Mar;75(6):605-16. doi: 10.1038/ki.2008.603. Epub 2008 Nov 26.

Abstract

Advanced glycation end products (AGEs) have been linked to the pathogenesis of diabetic nephropathy. Here we tested the effect of AGE-modified bovine serum albumin (AGE-BSA) on differentiated mouse podocytes in culture. Differential display and real-time PCR analyses showed that in addition to neuropilin-1, the entire signaling receptor complex of neuropilin-2, semaphorin-3A, and plexin-A1, was significantly reduced by AGE-BSA as was neuropilin-1 protein. The effect was specific for podocytes compared to isolated mesangial and tubular epithelial cells. Further, AGE-BSA was not toxic to podocytes. Neuropilin-1 expression was decreased in glomeruli of diabetic db/db mice compared to their non-diabetic littermates. Transcripts of both neuropilins were found to be decreased in renal biopsies from patients with diabetic nephropathy compared to transplant donors. Podocyte migration was inhibited by AGE-BSA with similar results found in the absence of AGE-BSA when neuropilin-1 expression was down-regulated by siRNA. In contrast, podocyte migration was stimulated by overexpression of neuropilin-1 even in the presence of AGE-BSA. Our study shows that AGE-BSA inhibited podocyte migration by down-regulating neuropilin-1. The decreased migration could lead to adherence of uncovered areas of the glomerular basement membrane to Bowman's capsule contributing to focal glomerulosclerosis.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Diabetes Mellitus
  • Diabetic Nephropathies / genetics
  • Down-Regulation / drug effects*
  • Gene Expression Profiling / methods
  • Gene Expression Regulation / drug effects
  • Glycation End Products, Advanced / pharmacology*
  • Humans
  • Kidney / metabolism
  • Mice
  • Nerve Tissue Proteins / genetics
  • Neuropilin-1 / antagonists & inhibitors*
  • Neuropilin-1 / genetics
  • Neuropilin-2 / genetics
  • Podocytes / metabolism*
  • RNA, Messenger / analysis
  • Receptors, Cell Surface / genetics
  • Semaphorin-3A / genetics
  • Serum Albumin, Bovine / pharmacology*

Substances

  • Glycation End Products, Advanced
  • Nerve Tissue Proteins
  • Neuropilin-2
  • Plxna1 protein, mouse
  • RNA, Messenger
  • Receptors, Cell Surface
  • Semaphorin-3A
  • advanced glycation end products-bovine serum albumin
  • Neuropilin-1
  • Serum Albumin, Bovine