Aging preserves mTORC1 but attenuates JNK-SMAD2L signaling sensitivity to passive stretch-induced tension development in isolated mouse skeletal muscle.

Kristiansen JB, Andresen J, Jakobsgaard JE, Vissing K · 2026 · Experimental gerontology · Atlas ID KRISTIANSEN2026

What this study shows

Passive mechanical stretch activates mTORC1 signaling (mTOR, p70S6K, rpS6, 4E-BP1) equally in adult and old mouse skeletal muscle, but JNK-SMAD2L signaling sensitivity to the same stretch is blunted with age — suggesting age-related anabolic resistance in muscle arises alongside or downstream of mTORC1, not from a defect in mTORC1 mechanosensing itself.

Abstract

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Aging is associated with impaired skeletal muscle mass and function, often attributed to reduced sensitivity to anabolic stimuli. This study investigated whether aging influences the sensitivity of key anabolic signaling pathways to mechanical tension development in skeletal muscle. Using an ex vivo model, extensor digitorum longus (EDL) muscles from adult (16 weeks) and old (24 months) female mice were subjected to a standardized passive stretch protocol, with contralateral muscles serving as controls.

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At a glance

Evidence type	A Animal model Marked A because it is an animal intervention or observation study measuring an organismal outcome (model: Mouse (ex vivo EDL muscle, adult 16-week vs old 24-month female mice)); the code names the system studied -- animal work can be rigorous and still not be human data.
Study type	4 - Animal Study
Model system	Mouse (ex vivo EDL muscle, adult 16-week vs old 24-month female mice)
Journal	Experimental gerontology
Year	2026
Peer reviewed	Yes
Record last updated	2026-08-22
Source	DOI 10.1016/j.exger.2026.113265 · PMID 42551770

Extracted findings

Intervention	Passive mechanical stretch
Target	mTORC1 (p70S6K, rpS6, 4E-BP1)
Model	Mouse
Effect	mTORC1 mechanosensitivity preserved with aging; differential anabolic pathway response

In the Atlas

Cite this paper

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Kristiansen, J. B., Andresen, J., Jakobsgaard, J. E., & Vissing, K. (2026). Aging preserves mTORC1 but attenuates JNK-SMAD2L signaling sensitivity to passive stretch-induced tension development in isolated mouse skeletal muscle. Experimental gerontology. https://doi.org/10.1016/j.exger.2026.113265

@article{KRISTIANSEN2026,
  author       = {Kristiansen, J. B. and Andresen, J. and Jakobsgaard, J. E. and Vissing, K.},
  title        = {{Aging preserves mTORC1 but attenuates JNK-SMAD2L signaling sensitivity to passive stretch-induced tension development in isolated mouse skeletal muscle}},
  journal      = {Experimental gerontology},
  year         = {2026},
  doi          = {10.1016/j.exger.2026.113265},
  note         = {PMID: 42551770},
}

Cite this Atlas record

The record is the Atlas's own work — the evidence label, the extracted findings and the links. It is cited as part of the dataset, not as the paper.

Barton, O. (2026). Oliver's mTOR Atlas (record KRISTIANSEN2026) [Data set]. https://mtor-atlas.org/study/KRISTIANSEN2026/ · Dataset DOI 10.5281/zenodo.22059963

@misc{atlas_KRISTIANSEN2026,
  author       = {Barton, Oliver},
  title        = {{Oliver's mTOR Atlas}, record KRISTIANSEN2026},
  howpublished = {Data set},
  year         = {2026},
  url          = {https://mtor-atlas.org/study/KRISTIANSEN2026/},
  doi          = {10.5281/zenodo.22059963}
}