Hindlimb Unloading Induces Bone Microarchitectural and Transcriptomic Changes in Murine Long Bones in an
Biorxiv : the Preprint Server for Biology
|October 24, 2023
Summary
Hindlimb unloading (HLU) causes bone loss similar to aging, affecting bone microarchitecture and gene expression. While HLU impacts younger mice by activating the senescence pathway, aging causes more significant changes in bone tissue and gene expression.
Area of Science:
- Bone biology and aging research.
- Skeletal physiology and disuse atrophy.
- Molecular mechanisms of bone loss.
Background:
- Bone mineral density, cortical thickness, and trabecular bone structure decrease with age and disuse.
- Disuse leads to physiological bone changes mirroring those of aging.
- Epiphyseal trabecular bone is particularly vulnerable to disuse-induced changes.
Approach:
- Compared bone microarchitecture and biomechanical properties in young, aged, and hindlimb unloaded (HLU) mice.
- Analyzed gene expression profiles from tibiae of HLU and control mice across different ages.
- Integrated publicly available datasets and used Ingenuity Pathway Analysis (IPA) to identify key pathways and regulators.
Key Points:
- HLU induced an intermediate bone phenotype between age-matched and aged controls, with epiphyseal trabecular bone being most affected.
- Gene expression changes due to HLU were age-dependent, affecting cellular processes in younger mice and mitochondrial function in older mice.
- The senescence pathway was activated by HLU in younger mice (3-4 months) but inhibited in skeletally mature mice (6 months).
Conclusions:
- Hindlimb unloading and aging induce similar bone microarchitecture and gene expression alterations.
- Aging results in more substantial transcriptome and tissue-level changes than hindlimb unloading.
- Disuse impacts bone health through age-dependent molecular pathways, including senescence and mitochondrial function.
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