Identification and antioxidative mechanism of novel mitochondria-targeted MFG-E8 polypeptides in virtual screening...

Area of Science:

• Biochemistry
• Molecular Biology
• Cell Biology

Background:

• Milk fat globule-EGF factor VIII (MFG-E8) contains bioactive peptides.
• The role of MFG-E8 polypeptides in sarcopenia and oxidative stress is not fully understood.
• Oxidative stress contributes to sarcopenia pathogenesis.

Purpose of the Study:

• To identify MFG-E8 derived polypeptides.
• To investigate the effects of these polypeptides on oxidative stress in dexamethasone-induced L6 cell injury.
• To elucidate the molecular mechanisms underlying their protective effects.

Main Methods:

• In vitro simulated digestion and liquid chromatography-tandem mass spectrometry (LC-MS/MS) for peptide identification.
• Molecular docking assays to predict binding affinities.
• Cell viability assays (MTT), oxidative stress assessment (dichlorodihydrofluorescein diacetate), mitochondrial and lysosomal activity tracking, transmission electron microscopy, and Western blotting.

Main Results:

• Ninety-five peptides were identified from MFG-E8 digestion, with 21 exceeding 1% abundance.
• IDLG and KDPG peptides demonstrated high binding affinity to keap1.
• IDLG and KDPG alleviated oxidative stress in L6 cells, improving mitochondrial function, reducing vacuolation, and enhancing autophagy.
• These peptides modulated the keap1/Nrf2/HO-1 signaling pathway by decreasing keap1 and increasing Nrf2, HO-1, and PGC-1α expression.

Conclusions:

• MFG-E8 derived peptides, specifically IDLG and KDPG, possess antioxidant properties.
• These peptides can mitigate oxidative stress-induced cellular damage, suggesting a therapeutic potential for sarcopenia.
• The protective effects are mediated through the keap1/Nrf2/HO-1 signaling pathway, highlighting a novel therapeutic target.