Document Detail


Advanced glycation end products impair protein turnover in LLC-PK1: amelioration by trypsin.
MedLine Citation:
PMID:  11168983     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
BACKGROUND: Advanced glycation end products (AGEs) are assumed to play a key role in the pathogenesis of diabetic nephropathy (DN) and other diabetic complications. While AGEs have been shown to exert marked effects on mesangial and endothelial cells as well as on monocytes/macrophages, little is known about their effects on tubule cells. Therefore, we addressed the questions of (1) whether AGE-bovine serum albumin (AGE-BSA) impairs the protein metabolism in the tubule cells, and if so, (2) whether the AGE-induced effects are mediated via a protease sensitive mechanism. METHODS: Arrested LLC-PK1 cells were exposed to a medium containing the vehicle (control, serum free), AGE-BSA (38 micromol/L), or BSA (38 micromol/L) in the presence or absence of trypsin (2.5 microg/mL) for 24 hours. We evaluated cell number, cell size, and cell protein content, as well as protein synthesis and protein degradation. RESULTS: After an incubation period of 24 hours, AGE-BSA decreased the cell number to 84.5 +/- 5.5% of control and 82.5 +/- 5.6% of BSA-treated cells (P < 0.05). [3H]-thymidine incorporation declined to 66% of control (P < 0.05), while BSA was without any effect. The same AGE-BSA dose reduced protein degradation (P < 0.05) and stimulated total protein synthesis slightly, as determined by L-[14C]Phe incorporation into acidic-insoluble proteins. These effects resulted in a rise in cell protein content (AGE-BSA vs. control, 21.9 +/- 6.7%; AGE-BSA vs. BSA, 11.1 +/- 6.0%, P < 0.05) and cell volume (AGE-BSA vs. control 9.4 +/- 3.2%, AGE-BSA vs. BSA 18.4 +/- 3.7%, P < 0.05). Coincubation with AGE-BSA and trypsin was associated with an amelioration of all investigated parameters concerning cell number, cell proliferation, raised cell protein content, decreased protein degradation, and enhanced protein synthesis. CONCLUSION: These data indicate that AGE-BSA impairs cell proliferation and protein turnover in LLC-PK1 cells with a consequent rise in cell protein. Since these alterations were abrogated by coincubation with trypsin, an interference of this serine protease with the AGE-binding proteins on cell surfaces is assumed.
Authors:
G Xiang; R Schinzel; A Simm; K Sebekova; A Heidland
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Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  Kidney international. Supplement     Volume:  78     ISSN:  0098-6577     ISO Abbreviation:  Kidney Int. Suppl.     Publication Date:  2001 Feb 
Date Detail:
Created Date:  2001-02-22     Completed Date:  2001-04-12     Revised Date:  2004-11-17    
Medline Journal Info:
Nlm Unique ID:  7508622     Medline TA:  Kidney Int Suppl     Country:  United States    
Other Details:
Languages:  eng     Pagination:  S53-7     Citation Subset:  IM    
Affiliation:
Department of Internal Medicine, Institute of Physiological Chemistry, University of Würzburg, Würzburg, Germany.
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MeSH Terms
Descriptor/Qualifier:
Animals
Cattle
Cell Division / drug effects
Cell Size / drug effects
Diabetic Nephropathies / etiology,  metabolism
Glycosylation End Products, Advanced / antagonists & inhibitors,  toxicity*
Humans
Kidney Tubules / cytology,  drug effects,  metabolism
LLC-PK1 Cells
Protein Biosynthesis
Proteins / metabolism*
Serum Albumin, Bovine / antagonists & inhibitors,  toxicity*
Swine
Trypsin / pharmacology*
Chemical
Reg. No./Substance:
0/Glycosylation End Products, Advanced; 0/Proteins; 0/Serum Albumin, Bovine; 0/advanced glycation end products-bovine serum albumin; EC 3.4.21.4/Trypsin

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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