Desmin forms toxic, seeding-competent amyloid aggregates that persist in muscle fibers

Niraja Kedia, Khalid Arhzaouy, Sara K. Pittman, Yuanzi Sun, Mark Batchelor, Conrad C. Weihl, Jan Bieschke

Research output: Contribution to journalArticle

5 Scopus citations

Abstract

Desmin-associated myofibrillar myopathy (MFM) has pathologic similarities to neurodegeneration-associated protein aggregate diseases. Desmin is an abundant muscle-specific intermediate filament, and disease mutations lead to its aggregation in cells, animals, and patients. We reasoned that similar to neurodegeneration-associated proteins, desmin itself may form amyloid. Desmin peptides corresponding to putative amyloidogenic regions formed seeding-competent amyloid fibrils. Amyloid formation was increased when disease-associated mutations were made within the peptide, and this conversion was inhibited by the anti-amyloid compound epigallocatechin-gallate. Moreover, a purified desmin fragment (aa 117 to 348) containing both amyloidogenic regions formed amyloid fibrils under physiologic conditions. Desmin fragment-derived amyloid coaggregated with full-length desmin and was able to template its conversion into fibrils in vitro. Desmin amyloids were cytotoxic to myotubes and disrupted their myofibril organization compared with desmin monomer or other nondesmin amyloids. Finally, desmin fragment amyloid persisted when introduced into mouse skeletal muscle. These data suggest that desmin forms seeding-competent amyloid that is toxic to myofibers. Moreover, small molecules known to interfere with amyloid formation and propagation may have therapeutic potential in MFM.

Original languageEnglish
Pages (from-to)16835-16840
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Volume116
Issue number34
DOIs
StatePublished - Aug 20 2019

Keywords

  • Amyloid
  • Desmin
  • Myofibrillar myopathy

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