Modulation of Prion Protein Oligomerization, Aggregation, and β-sheet Conversion by 4,4′-Dianilino-1,1′-binaphthyl-5,5′-sulfonate (bis-ANS)

Yraima Cordeiro,Luís Maurício T.R Lima,Mariana P.B Gomes,Débora Foguel,Jerson L Silva

doi:10.1074/jbc.m312262200

Yraima Cordeiro, Luís Maurício T.R Lima + Show 3 more

Open Access

https://doi.org/10.1074/jbc.m312262200

Copy DOI

Abstract

The prion protein (PrP) is the major agent implicated in the diseases known as transmissible spongiform encephalopathies. The onset of transmissible spongiform encephalopathy is related to a change in conformation of the PrP(C), which loses most of its alpha-helical content, becoming a beta-sheet-rich protein, known as PrP(Sc). Here we have used two Syrian hamster prion domains (PrP 109-141 and PrP 109-149) and the murine recombinant PrP (rPrP 23-231) to investigate the effects of anilino-naphtalene compounds on prion oligomerization and aggregation. Aggregation in the presence of bis-ANS (4,4'-dianilino-1,1'-binaphthyl-5,5'-sulfonate), ANS (1-anilinonaphthalene-8-sulfonate), and AmNS (1-amino-5-naphtalenesulfonate) was monitored. Bis-ANS was the most effective inhibitor of prion peptide aggregation. Bis-ANS binds strongly to rPrP 23-231 leading to a substantial increase in beta-sheet content and to limited oligomerization. More strikingly, the binding of bis-ANS to full-length rPrP is diminished by the addition of nanomolar concentrations of oligonucleotides, demonstrating that they compete for the same binding site. Thus, bis-ANS displays properties similar to those of nucleic acids, causing oligomerization and conversion to beta-sheet (Cordeiro, Y., Machado, F., Juliano, L., Juliano, M. A., Brentani, R. R., Foguel, D., and Silva, J. L. (2001) J. Biol. Chem. 276, 49400-49409). This dual effect of bis-ANS on prion protein makes this compound highly important to sequester crucial conformations of the protein, which may be useful to the understanding of the disease and to serve as a lead for the development of new therapeutic strategies.

Highlights

The prion protein (PrP)1 is known to be responsible for the diseases called transmissible spongiform encephalopathies, which are invariably fatal, including scrapie of sheep and goats, bovine spongiform encephalopathy (BSE) in cattle, and several human diseases such as Creutzfeldt-Jakob disease (CJD), Gerstmann-Straussler-Scheinker syndrome (GSS), and fatal familial insomnia (FFI) [1,2,3]
The onset of transmissible spongiform encephalopathy is related to a change in conformation of the PrPC, which loses most of its ␣-helical content, becoming a ␤-sheet-rich protein, known as PrPSc
The onset of a particular transmissible spongiform encephalopathy is caused by the conversion of the cellular PrP (PrPC), which is found predominantly on the outer surface of neurons attached to the membrane by a glycosyl phosphatidylinositol anchor, into an abnormal isoform, designated PrPSc [1]

Summary

The abbreviations used are

PrP, prion protein; PrPC, cellular prion protein; PrPSc, Scrapie prion protein; rPrP, full-length recombinant murine prion protein; bis-ANS, 4,4Ј-dianilino-1,1Ј-binaphthyl-5,5Ј-sulfonate; ANS, 1-anilinonaphthalene-8-sulfonate; AmNS, 1-amino-5naphtalenesulfonate; BSE, bovine spongiform encephalopathy. Our results show that bis-ANS inhibits prion peptide aggregation to a greater extent than AmNS and ANS, both aniline-naphtalene derived compounds (bis-ANS and ANS) bind to the prion domains studied in this work. When we tested the effect of bis-ANS binding on the recombinant murine prion protein, this compound triggered protein oligomerization, but inhibited aggregation. These results suggest a dual role for bis-ANS in the aggregation process, highly dependent on protein domain and conformational state.

EXPERIMENTAL PROCEDURES

DISCUSSION