The formation of intracellular glyceraldehyde-derived advanced glycation end-products and cytotoxicity.
BACKGROUND
Nonalcoholic steatohepatitis (NASH) is a feature of metabolic syndrome. Advanced glycation end-products (AGEs) are formed by the Maillard reaction, which contributes to aging and to certain pathological complications of diabetes. A recent study has suggested that glyceraldehyde-derived AGEs (Glycer-AGEs) are elevated in the sera of patients with NASH. Furthermore, immunohistochemistry of Glycer-AGEs showed intense staining in the livers of patients with NASH. The present study aimed to examine the effect of intracellular Glycer-AGEs on hepatocellular carcinoma (Hep3B) cells.


METHODS
Cell viability was determined by the WST-1 assay. The slot blot and Western blot were used to detect intracellular Glycer-AGEs, and their localization was analyzed by confocal microscopy. Real-time reverse transcription-polymerase chain reaction was used to quantify the mRNA for the acute phase reactant C-reactive protein (CRP).


RESULTS
Glyceraldehyde (GA), which is the precursor of Glycer-AGEs, induced a concentration- and time-dependent increase in cell death, which was associated with an increase in intracellular Glycer-AGEs formation. Aminoguanidine (AG), which prevents AGEs formation, inhibited the formation of intracellular Glycer-AGEs and prevented cell death. Among the intracellular Glycer-AGEs that were formed, heat shock cognate 70 (Hsc70) was identified as a GA-modified protein, and its modification reduced the activity of Hsc70. Furthermore, intracellular Glycer-AGEs increased the CRP mRNA concentration.


CONCLUSIONS
These results suggest that intracellular Glycer-AGEs play important roles in promoting inflammation and hepatocellular death.
Takino
Jun-ichi
J
Department of Pathophysiological Science, Faculty of Pharmaceutical Sciences, Hokuriku University, Kanazawa, 920-1181, Japan.
Kobayashi
Yuka
Y
Takeuchi
Masayoshi
M
D015153:Blotting, Western; D002097:C-Reactive Protein / Q000378:metabolism; D006528:Carcinoma, Hepatocellular / Q000503:physiopathology*; D016923:Cell Death; D045744:Cell Line, Tumor; D002470:Cell Survival; D004305:Dose-Response Relationship, Drug; D005234:Fatty Liver / Q000503:physiopathology; D017127:Glycation End Products, Advanced / Q000378:metabolism*; D005985:Glyceraldehyde / Q000008:administration & dosage / Q000378:metabolism*; D050883:HSC70 Heat-Shock Proteins / Q000378:metabolism; D006801:Humans; D007249:Inflammation / Q000209:etiology / Q000503:physiopathology; D008113:Liver Neoplasms / Q000503:physiopathology*; D018613:Microscopy, Confocal; D012333:RNA, Messenger / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013997:Time Factors
D017127:Glycation End Products, Advanced; D050883:HSC70 Heat-Shock Proteins; D012333:RNA, Messenger; D005985:Glyceraldehyde; D002097:C-Reactive Protein