Amyloid-β peptide (Aβ) conformational change and toxicity have been implicated in the etiology of Alzheimer's disease (1). In the present study, aimed to elucidate the micro-environmental conditions that drive peptide assembly and conformational state changes responsible of toxicity, we measured the effects of Aβ25-35 and Aβ1-42 incubation under pro-glycating conditions on its status of aggregation and toxicity.The lyophilized peptide Aβ25-35 was pre-treated with hexafluoro-2-propanol (HFIP), followed by treatment at 37°C for 72h in PBS pH 7,4, alone, or in the presence of copper and/or ribose. Aβ25-35 conformational changes were assayed by Dot-Blot using an anti-oligomer antibody (A-11) and Circular Dicroism (CD) measurements. Aβ25-35 toxicity was tested in human neuroblastoma cells (SH-SY5Y) treated for 24h with the different Aβ preparations measuring cell viability by MTT and also LDH release.CD spectra in the UV region of not treated Aβ25-35 showed a characteristic random coil structure, while CD spectra of treated Aβ25-35 owned a typical β-sheet conformation. Further details, obtained by Dot-Blot analysis of oligomers, revealed strongest signals (about +50% vs. the freshly prepared) after incubation in the presence of ribose and copper. Higher toxic activity was observed after Aβ25-35 incubation in the presence of ribose. Peptide aggregation and toxicity were inhibited in the presence of the dipeptide carnosine (β-alanyl-L-histidine). These results are in agreement with the notion that soluble Aβ oligomers and protofilaments, are responsible of cell death and demonstrate that pro-glycating microenviromental conditions favor changes toward toxic activity (2). New tools against amyloidogenesis, like treatment with carnosine and its derivatives, can be proposed to counteract the mechanism of glycation-induced protein cross-linking.1) Gong Y. et al PNAS 2003 100(18):10417-22.2) Loske C. et al Eur. J. Biochem. 2000 267(13):4171-8.Acknowledgements: FIRB RBNE 03PX83.
Aβ peptides oligomerization and toxicity under proglycating conditions
NICOLETTI, Vincenzo Giuseppe;SPINA, Vittoria Rita Annamaria;
2008-01-01
Abstract
Amyloid-β peptide (Aβ) conformational change and toxicity have been implicated in the etiology of Alzheimer's disease (1). In the present study, aimed to elucidate the micro-environmental conditions that drive peptide assembly and conformational state changes responsible of toxicity, we measured the effects of Aβ25-35 and Aβ1-42 incubation under pro-glycating conditions on its status of aggregation and toxicity.The lyophilized peptide Aβ25-35 was pre-treated with hexafluoro-2-propanol (HFIP), followed by treatment at 37°C for 72h in PBS pH 7,4, alone, or in the presence of copper and/or ribose. Aβ25-35 conformational changes were assayed by Dot-Blot using an anti-oligomer antibody (A-11) and Circular Dicroism (CD) measurements. Aβ25-35 toxicity was tested in human neuroblastoma cells (SH-SY5Y) treated for 24h with the different Aβ preparations measuring cell viability by MTT and also LDH release.CD spectra in the UV region of not treated Aβ25-35 showed a characteristic random coil structure, while CD spectra of treated Aβ25-35 owned a typical β-sheet conformation. Further details, obtained by Dot-Blot analysis of oligomers, revealed strongest signals (about +50% vs. the freshly prepared) after incubation in the presence of ribose and copper. Higher toxic activity was observed after Aβ25-35 incubation in the presence of ribose. Peptide aggregation and toxicity were inhibited in the presence of the dipeptide carnosine (β-alanyl-L-histidine). These results are in agreement with the notion that soluble Aβ oligomers and protofilaments, are responsible of cell death and demonstrate that pro-glycating microenviromental conditions favor changes toward toxic activity (2). New tools against amyloidogenesis, like treatment with carnosine and its derivatives, can be proposed to counteract the mechanism of glycation-induced protein cross-linking.1) Gong Y. et al PNAS 2003 100(18):10417-22.2) Loske C. et al Eur. J. Biochem. 2000 267(13):4171-8.Acknowledgements: FIRB RBNE 03PX83.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
