Influence of dendrimer’s structure on its activity against amyloid fibril formation

doi:10.1016/j.bbrc.2006.04.041

Biochemical and Biophysical Research Communications

Volume 345, Issue 1, 23 June 2006, Pages 21-28

https://doi.org/10.1016/j.bbrc.2006.04.041 Get rights and content

Abstract

Inhibition of fibril assembly is a potential therapeutic strategy in neurodegenerative disorders such as prion and Alzheimer’s diseases. Highly branched, globular polymers—dendrimers—are novel promising inhibitors of fibril formation. In this study, the effect of polyamidoamine (PAMAM) dendrimers (generations 3rd, 4th, and 5th) on amyloid aggregation of the prion peptide PrP 185–208 and the Alzheimer’s peptide Aβ 1–28 was examined. Amyloid fibrils were produced in vitro and their formation was monitored using the dye thioflavin T (ThT). Fluorescence studies were complemented with electron microscopy. The results show that the higher the dendrimer generation, the larger the degree of inhibition of the amyloid aggregation process and the more effective are dendrimers in disrupting the already existing fibrils. A hypothesis on dendrimer–peptide interaction mechanism is presented based on the dendrimers’ molecular structure.

Section snippets

Materials and methods

Materials. Synthetic peptides Aβ 1–28 [DAEFRHDSGYEVHHQKLVFFAEDVGSNK] and PrP 185–208 [KQHTVTTTTKGENFTETDVKMMER] were purchased from JPT Peptide Technologies GmbH (Germany). Stock peptide solutions were kept in aqueous buffer at pH 7.5. Thioflavin T (T-3516) and heparin–sodium salt (H-4784) were purchased from Sigma Chemical Company. Dendrimers PAMAM G3, PAMAM G4, and PAMAM G5 were obtained from Dendritic NanoTechnologies Inc. (USA) and dissolved in aqueous buffer. All other chemicals were of

Results

The fluorescence of thioflavin T is normally used to monitor the formation of amyloid fibrils. Fig. 1, Fig. 2 show the fluorescence variation of ThT for Aβ 1–28 and PrP 185–208 in the absence and presence of increasing concentrations of dendrimers. The time-dependent increase in ThT fluorescence follows a sigmoidal curve typical of a nucleated polymerization reaction. Peptide monomers slowly combine to form non-fibrilar structures known as nuclei (lag phase). Addition of peptide monomers to

Discussion

The presence of abnormal aggregates, so-called amyloid fibrils, is observed in several neurodegenerative disorders such as prion diseases and Alzheimer’s disease. The search for an effective treatment for these disorders is an up-to-date issue. Alzheimer’s dementia is a disease that threatens to overwhelm a health care system in the developed world. In contrast to Alzheimer’s disease, prion diseases can be transmitted from one organism to another. It was believed that the process cannot occur

Acknowledgments

This study was sponsored by Grant No. 12/IV/2005 from POLPHARMA Foundation for Development of Polish Pharmacy and Medicine and by Grants EET2002-05139 and BIO2003-02848 from the Spanish Ministry of Science and Education to J.C.

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Influence of dendrimer’s structure on its activity against amyloid fibril formation

Abstract

Section snippets

Materials and methods

Results

Discussion

Acknowledgments

FEBS Lett.

Biochem. Biophys. Res. Commun.

J. Biol. Chem.

Peptides

J. Struct. Biol.

Biophys. Chem.

J. Mol. Biol.

Biochim. Biophys. Acta

Biochim. Biophys. Acta

Bioelectrochem

Biochem. Biophys. Res. Commun.

J. Biol.Chem.

Drug Discovery Today

J. Mol. Biol.

J. Struct. Biol.

J. Struct. Biol.