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Lynch EM, Pittman S, Daw J, Ikenaga C, Chen S, Dhavale DD, Jackrel ME, Ayala YM, Kotzbauer P, Ly CV, Pestronk A, Lloyd TE, Weihl CC. Seeding competent TDP-43 persists in human patient and mouse muscle. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.04.03.587918. [PMID: 38617354 PMCID: PMC11014586 DOI: 10.1101/2024.04.03.587918] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/16/2024]
Abstract
TAR DNA-binding protein 43 (TDP-43) is an RNA binding protein that accumulates as aggregates in the central nervous system of some neurodegenerative diseases. However, TDP-43 aggregation is also a sensitive and specific pathologic feature found in a family of degenerative muscle diseases termed inclusion body myopathy (IBM). TDP-43 aggregates from ALS and FTD brain lysates may serve as self-templating aggregate seeds in vitro and in vivo, supporting a prion-like spread from cell to cell. Whether a similar process occurs in IBM patient muscle is not clear. We developed a mouse model of inducible, muscle-specific cytoplasmic localized TDP-43. These mice develop muscle weakness with robust accumulation of insoluble and phosphorylated sarcoplasmic TDP-43, leading to eosinophilic inclusions, altered proteostasis and changes in TDP-43-related RNA processing that resolve with the removal of doxycycline. Skeletal muscle lysates from these mice also have seeding competent TDP-43, as determined by a FRET-based biosensor, that persists for weeks upon resolution of TDP-43 aggregate pathology. Human muscle biopsies with TDP-43 pathology also contain TDP-43 aggregate seeds. Using lysates from muscle biopsies of patients with IBM, IMNM and ALS we found that TDP-43 seeding capacity was specific to IBM. Surprisingly, TDP-43 seeding capacity anti-correlated with TDP-43 aggregate and vacuole abundance. These data support that TDP-43 aggregate seeds are present in IBM skeletal muscle and represent a unique TDP-43 pathogenic species not previously appreciated in human muscle disease.
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Affiliation(s)
- Eileen M. Lynch
- Department of Neurology, Washington University in St Louis; St Louis, MO, USA
| | - Sara Pittman
- Department of Neurology, Washington University in St Louis; St Louis, MO, USA
| | - Jil Daw
- Department of Neurology, Washington University in St Louis; St Louis, MO, USA
| | - Chiseko Ikenaga
- Department of Neurology, Johns Hopkins University School of Medicine; Baltimore, MD, USA
| | - Sheng Chen
- Department of Chemistry, Washington University in St Louis; St Louis, MO, USA
| | - Dhruva D. Dhavale
- Department of Neurology, Washington University in St Louis; St Louis, MO, USA
| | - Meredith E. Jackrel
- Department of Chemistry, Washington University in St Louis; St Louis, MO, USA
| | - Yuna M. Ayala
- Department of Biochemistry and Molecular Biology, Saint Louis University; St Louis, MO, USA
| | - Paul Kotzbauer
- Department of Neurology, Washington University in St Louis; St Louis, MO, USA
| | - Cindy V. Ly
- Department of Neurology, Washington University in St Louis; St Louis, MO, USA
| | - Alan Pestronk
- Department of Neurology, Washington University in St Louis; St Louis, MO, USA
| | - Thomas E. Lloyd
- Department of Neurology, Baylor College of Medicine, Houston, TX, USA
| | - Conrad C. Weihl
- Department of Neurology, Washington University in St Louis; St Louis, MO, USA
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