ИСТИНА

INTRODUCTION: Synthetic and natural charged polymer, i.e. polyelectrolytes, are known to exhibit chaperone-like activity protecting the bound enzyme against aggregation [1,2]. In the present work, we performed a comprehensive study of influence of different polyelectrolytes on amyloid transformation and amyloid aggregation of two proteins: ovine prion protein associated with many prionopathies such as Creutzfeldt-Jakob and mad cow diseases, and alpha-synuclein associated with Parkinson’s disease. MATERIALS & METHODS: A range of polyanions and polycations differed in charge group, structure and molecular weight were examined. We used full-length ovine prion protein, variant VRQ, and recombinant alpha-synuclein, and analyzed propagation of amyloid structures, the size and structure of the complexes as well as its amyloidogenity and toxicity. Molecular modelling, namely atomistic molecular dynamics simulations, was used to look inside the mechanism of the action. RESULTS: All tested sulfated/sulfonated polymers induced amyloid transformation and oligomerization of prion protein. However, poly(styrene sulfonate) partially suppressed formation of amyloid fibrils by formation of the soluble complexes which exhibited reduced amyloidogenic capability in seeding experiments. Furthermore, treatment of prion fibrils with long chains of poly(styrene sulfonate) resulted in decrease of amount of amyloid structures. The same results were observed for amyloid inclusion bodies of prion protein [3]. Finally, sulfated polymers enhanced proteolytic degradation of amyloid fibrils by proteinase K. Besides, synthetic polyelectrolytes have been shown to efficiently suppress amyloid aggregation of alpha-synuclein. The presence of pyridinium polycations changed the aggregation mechanism from amyloid to amorphous. On the other hand, in the presence of poly(anethole sulfonate) or poly(styrene sulfonate) soluble complexes with size of 30 – 150 nm were formed instead of large amyloid fibrils according to dynamic light scattering and electron microscopy data. The binding of thioflavin T by these particles was significantly lower as compared to control fibrils indicating less amount of amyloid structures. DISCUSSION & CONCLUSIONS: The use of synthetic polyelectrolytes, especially sulfated and sulfonated polymers, is a prospective approach to treat amyloidosis. Although injection of the tested model polymers into brain or blood of patients seems to be impossible, our results provide a platform for creation of anti-amyloid complexes on the basis of tested and natural polymers. Furthermore, sulfated polymers can be used “as is” for treatment of products which potentially contain infectious prion species such as meat and bone meal used in cattle feed. Since amyloid fibrils are extremely stable, the possibility of its degradation including disruption of the fibrils and efficient proteolytic digestion is of special interest.