Delayed denervation-induced muscle atrophy in Opg knockout mice.

Area of Science:

• Muscle physiology and regeneration
• Skeletal biology
• Molecular signaling pathways

Background:

• The osteoprotegerin/receptor activator of nuclear factor κ-B ligand/RANK (OPG/RANKL/RANK) signaling axis is implicated in bone and muscle tissue.
• The specific role of OPG in muscle atrophy remains incompletely understood.

Purpose of the Study:

• To investigate the effect of OPG deficiency on muscle atrophy and functional recovery following denervation.
• To elucidate the molecular mechanisms underlying OPG's role in denervated muscle.

Main Methods:

• Utilized OPG knockout mice subjected to denervation.
• Assessed muscle functional recovery and atrophy.
• Analyzed ubiquitin-proteasome pathway activation.
• Performed transcriptome sequencing on denervated muscle.
• Conducted in vitro experiments on satellite cells.

Main Results:

• OPG knockout mice showed delayed muscle atrophy and improved functional recovery, particularly in type IIB fibers.
• OPG deficiency led to milder activation of the ubiquitin-proteasome pathway in denervated muscle.
• Transcriptome analysis revealed altered expression of genes including Inpp5k, Rbm3, Tet2, and Deptor in OPG-deficient muscle.
• Satellite cells from OPG knockout mice exhibited enhanced differentiation capacity, with higher Tet2 expression.

Conclusions:

• OPG plays a novel role in the muscle atrophy process.
• OPG deficiency confers protection against denervation-induced muscle damage.
• The findings expand the understanding of the OPG/RANKL/RANK signaling axis in muscle biology.