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bioRxiv

A receptor helps keep muscle stem cells unspecialized in mice

Mouse experiments found that steroid drugs’ effects on muscle repair were largely independent of the receptor in muscle stem cells.

Paper by E. Calvano, A. Bilger, J. G. Rizk, +8 more authorsD. Duteil · Igbmc

Our read

Mechanisms
Studied:
Preprint: experiments in mice
In the record:
One of 64 papers on dexamethasone on record: 13 with results in people, 17 in animals.
Why it’s aging research:
It studies organisms or tissues that aged naturally.

Editor of record: Boris Djordjevic · AgingResearch.News

Paper
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Young and aged mice underwent experiments on a steroid hormone receptor in satellite cells, the stem cells that help repair muscle. Deleting the receptor reduced the number of cells carrying a stem cell marker during regeneration in young mice, but did not substantially impair repair at either age. Gene activity analyses supported a role for the receptor in keeping resting stem cells from committing to become muscle cells.

Chronic treatment with the steroid drug prednisone changed gene activity in regenerating muscle differently with age, without substantially affecting tissue repair. Another steroid drug, dexamethasone, given during the early inflammatory phase, delayed regeneration. Dead tissue persisted, and more collagen, a structural protein, accumulated. The drugs’ effects on repair were comparable in mice with and without the receptor in satellite cells.

Why it matters

Muscle stem cells support tissue repair. Studying their hormone responses in aged mice addresses how that repair is regulated later in life.

Caveats

The muscle-repair results came from mice and do not establish how these drugs affect repair in people. The work is a preprint and has not been peer-reviewed.

Where the evidence stands

Prednisone

Humans: replicated by independent labs. Mice: a single group. Cells and worms or flies: nothing yet.

C, W, M, H: cells, worms or flies, mice, humans. Dark: independent labs found the same change there. Light: one lab or one study. Outline: nothing yet.

Labs are independent when their papers share no last author and no institution.

No results posted: trials that ended over a year ago with no results on ClinicalTrials.gov and no paper reporting them.

  • 8 independent labs in 6 countries
  • 1,260 trials, 348 with no results posted
  • Funders: National Institute of Diabetes and Digestive and Kidney Diseases and others

Dexamethasone

Cells and mice: replicated by independent labs. Humans: a single group. Worms or flies: nothing yet.

C, W, M, H: cells, worms or flies, mice, humans. Dark: independent labs found the same change there. Light: one lab or one study. Outline: nothing yet.

Labs are independent when their papers share no last author and no institution.

Against: findings that point the other way from most findings on the same outcome.

No results posted: trials that ended over a year ago with no results on ClinicalTrials.gov and no paper reporting them.

Company ties: findings with an author at a company, or from a paper whose competing-interests statement declares ties to one.

  • 35 independent labs in 16 countries
  • 4 findings against
  • 2,158 trials, 613 with no results posted
  • Funders: National Institutes of Health and others
  • 1 of 76 findings with company ties
  • 82 of 2,158 trials sponsored by its developers

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