preclinical validation of the heparin-reactive peptide p5+14 as a molecular imaging agent for visceral amyloidosis
;Jonathan S. Wall;Emily B. Martin;Tina Richey;Alan C. Stuckey;Sallie Macy;Craig Wooliver;Angela Williams;James S. Foster;Penney McWilliams-Koeppen;Ed Uberbacher;Xiaolin Cheng;Stephen J. Kennel
Journal of ethnopharmacology2015Vol. 20pp. 7657-7682
277
wall2015moleculespreclinical
Abstract
Amyloid is a complex pathologic matrix comprised principally of paracrystalline protein fibrils and heparan sulfate proteoglycans. Systemic amyloid diseases are rare, thus, routine diagnosis is often challenging. The glycosaminoglycans ubiquitously present in amyloid deposits are biochemically and electrochemically distinct from those found in the healthy tissues due to the high degree of sulfation. We have exploited this unique property and evaluated heparin-reactive peptides, such as p5+14, as novel agents for specifically targeting and imaging amyloid. Herein, we demonstrate that radiolabeled p5+14 effectively bound murine AA amyloid in vivo by using molecular imaging. Biotinylated peptide also reacted with the major forms of human amyloid in tissue sections as evidenced immunohistochemically. Furthermore, we have demonstrated that the peptide also binds synthetic amyloid fibrils that lack glycosaminoglycans implying that the dense anionic motif present on heparin is mimicked by the amyloid protein fibril itself. These biochemical and functional data support the translation of radiolabeled peptide p5+14 for the clinical imaging of amyloid in patients.