miR-628 Promotes Burn-Induced Skeletal Muscle Atrophy via Targeting IRS1

Area of Science:

• Biochemistry
• Molecular Biology
• Physiology

Background:

• Skeletal muscle atrophy is common in severe burn patients.
• MicroRNAs (miRNAs) regulate stress-induced muscle atrophy.
• Our prior work identified miR-628 in burn-induced atrophy.

Purpose of the Study:

• To investigate the role of miR-628 in burn-induced skeletal muscle atrophy.
• To elucidate the molecular mechanisms underlying miR-628's function.
• To explore potential therapeutic targets for burn-induced muscle wasting.

Main Methods:

• Burn injury model in rats and L6 myocyte cell culture.
• miRNA array analysis to quantify miR-628 levels.
• Western blotting for protein expression (IRS1, Akt, FoxO3a, cleaved caspase 3).
• In vivo forced miR-628 expression and apoptosis inhibition (Z-VAD-FMK).

Main Results:

• Burn injury induced skeletal muscle atrophy, increased cell apoptosis, and elevated miR-628 levels.
• miR-628 overexpression in myocytes increased apoptosis and decreased IRS1/Akt, while increasing FoxO3a and cleaved caspase 3.
• Forced miR-628 expression in rats mimicked burn-induced atrophy and pathway changes.
• Apoptosis inhibition partially alleviated burn-induced skeletal muscle atrophy.

Conclusions:

• miR-628 is a key mediator of burn-induced skeletal muscle atrophy.
• miR-628 regulates atrophy by modulating the IRS1/Akt/FoxO3a signaling pathway.
• Targeting miR-628 or downstream apoptotic pathways may offer therapeutic benefits.