Aging increases CCN1 expression leading to muscle senescence.

Area of Science:

• Muscle biology
• Aging research
• Cellular senescence

Background:

• Sarcopenia, age-related muscle loss, impacts mobility and health.
• The role of specific proteins and signaling pathways in sarcopenia is not fully understood.
• Identifying molecular mechanisms driving muscle aging is crucial for therapeutic development.

Purpose of the Study:

• To investigate the role of the matricellular protein CCN1 in age-related sarcopenia.
• To identify potential circulating factors that regulate CCN1 expression in aging muscle.
• To elucidate the molecular mechanisms by which CCN1 contributes to muscle cell senescence.

Main Methods:

• Microarray analysis to assess gene expression changes in aging muscle.
• Western blot analysis to quantify protein levels of CCN1 and related cell cycle regulators.
• In vitro experiments treating muscle progenitor cells (MPCs) with recombinant CCN1 and aged serum.
• Transduction of C2C12 myoblasts with Wnt-3a to study its effect on CCN1 expression.

Main Results:

• CCN1 mRNA and protein levels were significantly elevated in the muscles of aged rats and mice.
• Recombinant CCN1 treatment decreased MPC proliferation and induced senescence markers, alongside increased p53, p16(Ink4A), and pRP levels.
• Aged serum increased CCN1 expression in MPCs, suggesting a circulating regulator.
• Wnt-3a levels were higher in aged human and rodent serum and Wnt-3a treatment increased CCN1 in myoblasts.

Conclusions:

• The matricellular protein CCN1 is upregulated in aging muscle and contributes to muscle progenitor cell senescence.
• The circulating factor Wnt-3a stimulates CCN1 expression in aging muscle.
• This Wnt-3a/CCN1 pathway promotes muscle senescence by activating cell growth arrest proteins, offering potential therapeutic targets.