Induction of AApoAII and AA amyloidosis by the injections of various amyloid fibrils

Preformed amyloid fibrils accelerate conformational changes of amyloid precursor proteins and result in a rapid extension of amyloid fibrils in vitro. In this paper, we show the induction of AApoAII amyloidosis in vivo by various human and mouse amyloid fibrils isolated from human and mouse tissues or formed in vitro from synthetic peptides and recombinant proteins. These fibrils were injected intravenously into R1.P1-Apoa2(c) mice. At 3 and 6 months after injection, amyloid deposition was examined. Severe amyloid depositions were detected in the tissues of mice injected with AApoAII (C) amyloid fibrils. Mild or slight amyloid depositions were also detected in the tissues of mice, which were injected with other types of fibrils, including synthetic peptides. However, no amyloid depositions were found in the control mice, which were injected with non-amyloid fibril proteins. In addition, AA amyloidosis was accelerated by the various amyloid fibrils in C57BL/6 mice, which were injected simultaneously and subcutaneously with 1.0% AgNO3. These results demonstrated that various exogenous substances with a common structure could work as seeds for amyloid fibril formation in vivo. These findings suggested a prion-like mechanism of protein conformation in the pathogenesis of mouse AApoAII and AA amyloidosis. (C) 2003 Elsevier B.V. All rights reserved.