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Co-infection with two α-synuclein strains reveals novel synergistic interactions
Sara A M Holec, Chase R Khedmatgozar, Shelbe J Schure, Jason C Bartz, Amanda L Woerman. Acta neuropathologica, 2025-11-08
Topic: Disease mechanisms in lab and animal studies
In synucleinopathies, the protein α-synuclein misfolds into Lewy bodies (LBs) in patients with Lewy body disease (LBD) or into glial cytoplasmic inclusions (GCIs) in patients with multiple system atrophy (MSA). The ability of a single misfolded protein to cause disparate diseases is explained by the prion strain hypothesis, which argues that protein conformation is a major determinant of disease. We recently reported the unexpected finding of a novel α-synuclein strain in a Parkinson's disease with dementia patient sample containing GCI-like co-pathology along with widespread LB pathology, which led us to question if two α-synuclein strains can interact with one another in a patient and, if so, can strain competition occur. To test this possibility, we used the strain interference model developed in the prion field, in which a slower replicating strain-in this study, mouse-passaged MSA-is used to compete with a faster replicating strain-here, recombinant preformed fibrils (PFFs)-following sciatic nerve (sc.n.) inoculation. Unexpectedly, we found that PFFs generated using the same method differed in their ability to neuroinvade following sc.n. inoculation based on α-synuclein monomer source. Using a PFF preparation that does spread from the periphery, we conducted strain competition studies by first injecting TgM83+/- mice with mouse-passaged MSA into the sc.n. followed by a second injection with PFFs at 30, 45, and 60% of the MSA incubation period. We found that the two α-synuclein strains exhibited a synergistic effect during neuroinvasion, which was characterized by a decrease in incubation period along with evidence of the mouse-passaged MSA strain in the brain of terminal animals. These findings indicate that two α-synuclein strains can synergize with one another to accelerate the progression of clinical disease, representing a novel outcome in mixed infection studies.
Key findings
- Unexpectedly, we found that PFFs generated using the same method differed in their ability to neuroinvade following sc.n. inoculation based on α-synuclein monomer source.
- We found that the two α-synuclein strains exhibited a synergistic effect during neuroinvasion, which was characterized by a decrease in incubation period along with evidence of the mouse-passaged MSA strain in the brain of terminal animals.
- These findings indicate that two α-synuclein strains can synergize with one another to accelerate the progression of clinical disease, representing a novel outcome in mixed infection studies.
Study details
- Evidence strengthLow
How this study scored 46/100
Published in a leading specialty journal. Scored zero for study design, sample size, effect reported, studied in people and randomised / blinded because the record does not state it. We have no data on journal's citation record, times cited, citations per year, impact for its field and year, cited by studies here, still being cited, senior author's track record, institution's track record, multi-centre collaboration and free to read, so those were left out: it earned 26 of the 56 points we could judge it on, which is 46 out of 100.
| Component | Points | Why |
|---|---|---|
| Journal tier | 9 / 10 | Tier 2 — leading specialty journal (Acta neuropathologica) |
| Journal's citation record | — / 4 | No journal record from OpenAlex — left out of this score |
| Study design | 0 / 12 | No study design recorded — scores zero, not guessed (not stated in the record — scored 0) |
| Strength of evidence | 1 / 5 | Rated “low” in our summary |
| Peer-review validation | 10 / 10 | Peer-reviewed. Published as an article in a named peer-reviewed journal. |
| How recent | 4 / 5 | 2025 — within 3 year(s) of the newest study here |
| Sample size | 0 / 4 | Participant count not stated — scores zero (not stated in the record — scored 0) |
| Effect reported | 0 / 3 | No effect size reported — scores zero (not stated in the record — scored 0) |
| Studied in people | 0 / 3 | Not stated whether this was studied in people — scores zero (not stated in the record — scored 0) |
| Randomised / blinded | 0 / 2 | No randomisation or blinding stated — scores zero (not stated in the record — scored 0) |
| Times cited | — / 7 | No citation count (not found in OpenAlex) — left out of this score |
| Citations per year | — / 5 | No citation count or no year — left out of this score |
| Impact for its field and year | — / 6 | No field-weighted citation impact (OpenAlex has none yet) — left out of this score |
| Cited by studies here | — / 6 | Not yet checked against this library's citation graph — left out of this score |
| Still being cited | — / 4 | No yearly citation counts — left out of this score |
| Senior author's track record | — / 4 | Senior author's record not available — left out of this score |
| Institution's track record | — / 3 | No institution listed in OpenAlex — left out of this score |
| Multi-centre collaboration | — / 3 | Institutions not listed — left out of this score |
| Indexed in PubMed | 2 / 2 | Indexed in PubMed (PMID 41206373) |
| Free to read | — / 2 | Access not recorded — left out of this score |
| Points | 26 / 56 | Scored on 10 of 20 parts. We have no data for the rest, so they are left out: 26 of the 56 points we could judge it on is 46 out of 100. |
| Total | 46 / 100 | — |
What each of these 20 components measures, and what this score is not →
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Cite this study APA, Vancouver, BibTeX · download .bib or .ris
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APA 7th
Holec, S. A. M., Khedmatgozar, C. R., Schure, S. J., Bartz, J. C., & Woerman, A. L. (2025). Co-infection with two α-synuclein strains reveals novel synergistic interactions. Acta neuropathologica. https://doi.org/10.1007/s00401-025-02957-5
Vancouver
Holec SAM, Khedmatgozar CR, Schure SJ, Bartz JC, Woerman AL. Co-infection with two α-synuclein strains reveals novel synergistic interactions. Acta neuropathologica. 2025. doi:10.1007/s00401-025-02957-5. PMID: 41206373.
BibTeX
@article{holec2025-41206373,
author = {Holec, Sara A M and Khedmatgozar, Chase R and Schure, Shelbe J and Bartz, Jason C and Woerman, Amanda L},
title = {{Co-infection with two α-synuclein strains reveals novel synergistic interactions}},
journal = {Acta neuropathologica},
year = {2025},
doi = {10.1007/s00401-025-02957-5},
pmid = {41206373},
url = {https://doi.org/10.1007/s00401-025-02957-5}
}
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