Estrogens maintain skeletal muscle and satellite cell functions

Area of Science:

• Endocrinology
• Muscle Physiology
• Cell Biology

Background:

• Estrogens regulate critical physiological functions, including cellular processes and metabolism.
• Estrogen receptors (ERs) are present in skeletal muscle and its stem cells (satellite cells).
• The impact of prolonged estrogen deficiency on muscle and satellite cell function is not well understood.

Purpose of the Study:

• To investigate the effects of estrogen reduction on skeletal muscle function and regeneration in young female mice.
• To determine how prolonged estrogen insufficiency influences muscle atrophy, force generation, fiber type, and satellite cell behavior.

Main Methods:

• Utilized young ovariectomized (OVX) female mice to model prolonged estrogen insufficiency.
• Assessed muscle mass, muscle force generation, and myosin heavy chain (MHC) isoforms.
• Quantified satellite cell number, expansion, differentiation, and self-renewal capacity.
• Evaluated muscle regeneration capacity post-injury.

Main Results:

• Estrogen reduction led to time-dependent muscle atrophy and reduced muscle force generation in OVX mice.
• Prolonged estrogen insufficiency induced a shift towards faster myosin heavy chain isoforms in muscle fibers.
• While satellite cell numbers remained unchanged, their expansion, differentiation, and self-renewal capabilities were significantly impaired.
• Muscle regeneration was markedly compromised in OVX mice compared to controls.

Conclusions:

• Estrogens are essential for maintaining overall muscle function in young female mice.
• Estrogen insufficiency negatively affects muscle strength, fiber type composition, and regenerative capacity.
• Impaired satellite cell function is a key mechanism by which estrogen deficiency compromises muscle regeneration.