Cytotoxicity of Abeta1-42, RAGE23-54, and an Abeta-RAGE complex in PC-12 cells.
The receptor for advanced glycation end products (RAGE) binds amyloid peptides with high affinity. Soluble RAGE-like peptides and Abeta-like peptides occur in relatively high concentrations in the circulation of individuals with Alzheimer's disease. Protein complexes with epitopes for both Abeta and RAGE are also present. At physiological concentrations, forms of Abeta have different, but relatively low potencies as cytotoxicants in neural cells in culture. The purpose of this study was to determine whether a synthetic peptide complex composed of Abeta(1-42) and RAGE(23-54), a conserved N-terminal fragment of RAGE, exhibited increased cytotoxicity in comparison with the constituent peptides. Western analysis indicated that Abeta(1-42) and RAGE(23-54) remained primarily in their original low molecular weight states (4-6 kDa) during the maintenance of the individual peptides (37 degrees C) in water from 1 to 4 weeks. In contrast, over the same maintenance periods the combined Abeta(1-42) and RAGE(23-54) peptides shifted to higher molecular weight complexes (up to 80-120 kDa). Protein complexes of similar molecular weights with epitopes for Abeta and RAGE antibodies were identified in human plasma. Incubation of differentiated PC-12 cells with 10-100 microM Abeta(1-42) or with RAGE(23-54) resulted in concentration-dependent decreases in cell viability. The cytotoxicity of each peptide was slightly enhanced by the progressive maintenance of Abeta(1-42) and RAGE(23-54) in water over 3 weeks prior to the assay. Under the same conditions, the Abeta(1-42) - RAGE(23-54) complex became significantly more cytotoxic. These results suggest that the formation of soluble Abeta-RAGE complexes in Alzheimer's disease could represent a mechanism for enhancing the neurotoxicity of amyloid peptides.
Mruthinti
Shyamala
S
Veterans Administration Medical Center, Augusta, Georgia 30904-6285, USA.
Capito
Nicholas
N
Sood
Ajay
A
Buccafusc
Jerry J
JJ
D016229:Amyloid beta-Peptides / Q000378:metabolism / Q000633:toxicity*; D000704:Analysis of Variance; D000818:Animals; D002470:Cell Survival / Q000187:drug effects*; D004338:Drug Combinations; D017127:Glycation End Products, Advanced / Q000737:chemistry*; D006801:Humans; D016716:PC12 Cells / Q000187:drug effects* / Q000378:metabolism; D010446:Peptide Fragments / Q000633:toxicity*; D051381:Rats; D013997:Time Factors
D016229:Amyloid beta-Peptides; D004338:Drug Combinations; D017127:Glycation End Products, Advanced; D010446:Peptide Fragments; C075222:amyloid beta-protein (1-42)