NR AWGH
AU Hafner Bratkovic,I.; Gaspersic,J.; Smid,L.M.; Bresjanac,M.; Jerala,R.
TI In vitro study of curcumin labeling of prion plaques and prion fibrils
QU International Conference - Prion 2006: Strategies, advances and trends towards protection of society - 3.10.-6.10.2006, Torino, Italy, Lingotto Conference Centre - Poster sessions DIA-22
PT Konferenz-Poster
AB
Amyloid fibril formation and aggregation in the brain is a hallmark of several neurodegenerative diseases for which there is no treatment, yet. Representatives of these diseases are Alzheimer disease and prion diseases. In both neurodegenerative disorder types the diagnosis is typically achieved either late in the manifest stage of the clinical disease, or even postmortem. Amyloidbinding molecules that can serve as imaging agents to quantify amyloid plaque loads in living brain have the potential to determine the extent of in vivo pathology. Several compounds have been developed and may be particularly useful for evaluating antiamyloid-directed therapeutic interventions. Some of the tested compounds that bind and fluorescently label amyloid in vitro like the yellow curry pigment curcumin, may have additional effects. For example, curcumin has potent antiinflammatory and antioxidant activities and can suppress oxidative damage and inflammation. Low dose curcumin has recently also been shown to effectively disaggregate amyloid beta aggregates and to prevent fibril and oligomer formation (1), revealing its tentative therapeutic potential. Interestingly, it had also been shown to potently inhibit scrapie prion accumulation in scrapie agent-infected neuroblastoma cells (2). The aim of our ongoing work has been to evaluate curcumin for its ability to label prion amyloid plaques in postmortem brain sections of human prion disease victims. Furthermore, we have aimed at determining the binding characteristics of curcumin to recombinant prion protein fibrills in vitro. We employed sequential labeling of 5microm thick tissue sections of paraformaldehyde-fixed paraffin-embedded brain of a variant Creutzfeldt-Jakob disease victim: curcumin labeling was applied first and the labeled sites were photographed. This was followed with immunohistochemistry to prion protein and repeat photographing of the same sites. Fluorimetric binding assay was performed to determine the binding characteristics of curcumin to recombinant prion protein fibrills. The results showed that: (a) curcumin reproducibly and selectively labeled prion plaques in brain tissue sections, and (b) in the fluorimetric assay, curcumin labeled prion protein fibrills (but not the natively folded prion protein) with the binding constant in the submicromolar (Kd=0.3 microM) range. Our results suggest that curcumin may have a considerable diagnostic potential and prompt further studies to better assess its usefulness in prion diseases.
1 Yang et al. 2005, J biol chem 280, 5892-5901. 2 Caughey et al. 2003, J Virol 77, 5499-5502. This work has been supported by grants from Slovenian Research Agency (M.B., R.J.)
AD I. Hafner Bratkovic, J. Gaspersic, R. Jerala: Laboratory of biotechnology, National Institute of Chemistry, Hajdrihova 19, Slovenia; L.M. Smid, M. Bresjanac: LNPR, Institute of Pathophysiology, Medical faculty, University of Ljubljana, Zaloska 4 1000 Ljubljana, Slovenia
SP englisch
PO Italien