Amyloid seeding of transthyretin by ex vivo cardiac fibrils and its inhibition

Abstract

Significance Transthyretin (TTR) cardiac amyloidosis is characterized by the deposition of TTR amyloid fibrils in the heart. No therapy is currently available for wild-type cardiac amyloidosis. Hereditary cases are treated by liver transplantation, a crude form of gene therapy which replaces amyloidogenic mutant TTR by the more stable wild-type form, with the goal of halting further deposition and disease progression. However, wild-type TTR continues to deposit in the heart of many patients after the procedure. Until now, seeding of TTR fibril formation has not been demonstrated in vitro. We show that patient-extracted cardiac fibrils can seed both wild-type and mutant TTR fibril formation in vitro. This process can be inhibited by structure-based peptide inhibitors, thereby providing an alternative approach to therapy.