title: Extracellular matrix is modulated in advanced glycation end products milieu via a RAGE receptor dependent pathway boosted by transforming growth factor-β1 RAGE.
abstract: BACKGROUND
  Interstitial fibrosis is induced by imbalances in extracellular matrix homeostasis. Advanced glycation end products (AGEs) can bind and activate the receptor for AGEs (RAGE), which is involved in diabetic nephropathy. We set out to identify the role of AGEs in producing alterations leading to matrix hypertrophy and the pathway through which aminoguanidine, as well as anti-RAGE and anti-transforming growth factor (TGF)-β1 antibody treatments could prevent these modifications.
  
  
  METHODS
  Human embryonic kidney (HEK-293) cells were exposed to glycated bovine serum albumin (AGE-BSA) and co-treated with neutralizing antibodies or aminoguanidine. The effects on the transcriptional and translational levels of RAGE, TGF-β1 and collagen IV were evaluated, while metalloproteinase activity was assessed by gelatin zymography.
  
  
  RESULTS
  AGE-BSA (200 μg/mL) upregulated RAGE's expression, while TGF-β1 synthesis and the formation of its bioactive form were increased in a dose-dependent manner by AGEs. AGE-BSA exposure increased both matrix metalloproteinase (MMP) activity and collagen IV synthesis, boosted by TGF-β1 upregulation. Aminoguanidine's effects revealed that small concentrations (10 μmol/L) enhance AGE-BSA effects, by increasing the expression of RAGE and TGF-β1, while higher concentrations (100 μmol/L) contribute to their downregulation.
  
  
  CONCLUSIONS
  Although AGEs regulate RAGE and TGF-β1 by distinct pathways, RAGE activation leads to a further increase of TGF-β1 levels. MMP-2 activity seems to rely on TGF-β1, while MMP-9 was dependent on RAGE. These factors converge to control collagen IV turnover. Furthermore, although the antibody treatments might appear more efficient than AG in decreasing collagen IV levels, the cells compensate the RAGE and TGF-β1 blockade by increasing the mRNA expression of these proteins.
authors.affiliation: Department of Preclinical Sciences, University of Agronomical Sciences and Veterinary Medicine, Bucharest, Romania.
authors.forename: Andreea Iren
authors.initials: AI
authors.lastname: Serban
authors.forename: Loredana
authors.initials: L
authors.lastname: Stanca
authors.forename: Ovidiu Ionut
authors.initials: OI
authors.lastname: Geicu
authors.forename: Maria Cristina
authors.initials: MC
authors.lastname: Munteanu
authors.forename: Marieta
authors.initials: M
authors.lastname: Costache
authors.forename: Anca
authors.initials: A
authors.lastname: Dinischiotu
mesh_terms: D000818:Animals; D015153:Blotting, Western; D002417:Cattle; D024141:Collagen Type IV / Q000235:genetics / Q000378:metabolism*; D003928:Diabetic Nephropathies; D005109:Extracellular Matrix / Q000378:metabolism*; D005355:Fibrosis; D005786:Gene Expression Regulation; D017127:Glycation End Products, Advanced / Q000235:genetics / Q000378:metabolism / Q000494:pharmacology*; D057809:HEK293 Cells; D006801:Humans; D020778:Matrix Metalloproteinase 2 / Q000235:genetics / Q000378:metabolism*; D020780:Matrix Metalloproteinase 9 / Q000235:genetics / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics; D060888:Real-Time Polymerase Chain Reaction; D000067759:Receptor for Advanced Glycation End Products; D011971:Receptors, Immunologic / Q000235:genetics / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012710:Serum Albumin, Bovine / Q000235:genetics / Q000378:metabolism*; D053773:Transforming Growth Factor beta1 / Q000494:pharmacology*; D015854:Up-Regulation
chemical_list: D024141:Collagen Type IV; D017127:Glycation End Products, Advanced; D012333:RNA, Messenger; D000067759:Receptor for Advanced Glycation End Products; D011971:Receptors, Immunologic; D053773:Transforming Growth Factor beta1; C081628:advanced glycation end products-bovine serum albumin; D012710:Serum Albumin, Bovine; C522361:MMP2 protein, human; D020778:Matrix Metalloproteinase 2; C579270:MMP9 protein, human; D020780:Matrix Metalloproteinase 9
keywords: advanced glycation end products; aminoguanidine; matrix hypertrophy; matrix metalloproteinase; transforming growth factor-β1; 关键词：晚期糖基化终末产物，氨基胍，基质增生，基质金属蛋白酶，转化生长因子-β1