251: MuSCs, laminin-α2 and LAMA2 MD

McGowan TJ et al., Nature Communications, doi:10.1038/s41467-025-65703-1 - Activated muscle stem cells express and secrete laminin-α2 to remodel their niche, and loss of MuSC-derived laminin-α2 slows MuSC proliferation and delays regeneration in mouse models and human iPSC-derived precursors. Key terms: laminin-α2, muscle stem cells, LAMA2 MD, regeneration, proliferation.

Study Highlights:
Activated MuSCs upregulate Lama2 and deposit laminin-α2 around proliferating cells during early regeneration. MuSCs from Lama2-deficient dyW/dyW mice progress more slowly through S phase, accumulate in G1, and show reduced expansion ex vivo and in vivo. Transplantation of dyW/dyW MuSCs into wild-type muscle does not restore their proliferative capacity, indicating a cell-intrinsic defect. A MuSC-specific Lama2 knockout recapitulates the slower proliferation and reduces early injury-associated laminin-α2, delaying muscle repair. Isogenic human LAMA2 knockout myogenic precursors also incorporate less EdU and show transcriptional changes consistent with impaired cell-cycle progression.

Conclusion:
Self-secreted laminin-α2 is required cell-autonomously for efficient MuSC proliferation and timely muscle regeneration, implicating MuSC dysfunction as a contributor to LAMA2-related muscular dystrophy pathology

Music:
Enjoy the music based on this article at the end of the episode.

Article title:
Loss of cell-autonomously secreted laminin-α2 drives muscle stem cell dysfunction in LAMA2-related muscular dystrophy

First author:
McGowan TJ

Journal:
Nature Communications, doi:10.1038/s41467-025-65703-1

DOI:
10.1038/s41467-025-65703-1

Reference:
McGowan TJ, Reinhard JR, Lewerenz N, Białobrzeska M, Lin S, Stępniewski J, Szade K, Dulak J & Rüegg MA. Loss of cell-autonomously secreted laminin-α2 drives muscle stem cell dysfunction in LAMA2-related muscular dystrophy. Nature Communications (2025) 16:10674. https://doi.org/10.1038/s41467-025-65703-1

License:
This episode is based on an open-access article published under the Creative Commons Attribution 4.0 International License (CC BY 4.0) – https://creativecommons.org/licenses/by/4.0/

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QC:
This episode was checked against the original article PDF and publication metadata for the episode release published on 2026-01-06.

QC Scope:
- article metadata and core scientific claims from the narration
- excludes analogies, intro/outro, and music
- transcript coverage: Substantively audited the transcript’s coverage of: MuSC expression/secreted laminin-α2; intrinsic MuSC proliferation defects in dyW/dyW mice; transplantation results; MuSC-specific Lama2 knockout; human LAMA2 KO hiPSC model; and downstream signaling/cell-cycle implications.
- transcript topics: MuSC activation and Lama2 expression; MuSC secretion and remodeling with laminin-α2; dyW/dyW mouse model: regeneration defects and MuSC proliferation; ex vivo MuSC proliferation assays (EdU, cell cycle); MuSC transplantation experiments and intrinsic vs extrinsic defect; MuSC-specific Lama2 knockout effects on proliferation

QC Summary:
- factual score: 10/10
- metadata score: 10/10
- supported core claims: 8
- claims flagged for review: 0
- metadata checks passed: 4
- metadata issues found: 0

Metadata Audited:
- article_doi
- article_title
- article_journal
- license

Factual Items Audited:
- Activated MuSCs express Lama2 and deposit laminin-α2 into their microenvironment
- MuSC-derived laminin-α2 is essential for rapid MuSC expansion and timely muscle regeneration
- Lama2-deficient MuSCs proliferate more slowly ex vivo and show delayed regeneration in dyW/dyW mice
- Transplantation of Lama2-deficient MuSCs shows reduced tissue remodeling capacity in vivo
- MuSC-specific Lama2 knockout slows MuSC proliferation and delays regeneration
- LAMA2 knockout in human hiPSCs slows cell-cycle progression and downregulates G2/M and E2F-related pathways (p53 pathway up)

QC result: Pass.