Endorepellin-evoked Autophagy Contributes to Angiostasis

Area of Science:

• Cell Biology
• Molecular Biology
• Biophysics

Background:

• Endorepellin, the C-terminal domain of perlecan, is known to possess angiostatic properties.
• Its mechanism of action involves inducing autophagy, a cellular degradation process, through interaction with VEGFR2.

Purpose of the Study:

• To investigate the effects of endorepellin on endothelial cell morphology and biophysical properties.
• To elucidate the role of autophagy in endorepellin-mediated angiostasis.

Main Methods:

• Atomic force microscopy was used to assess changes in endothelial cell surface roughness, height, and elastic modulus.
• Immunofluorescence microscopy was employed to observe the co-localization of autophagy-related proteins (mTOR, LC3, Beclin 1).
• Inhibition of AMP-activated kinase α (AMPKα) was performed using compound C to study its role in endorepellin's effects.

Main Results:

• Endorepellin induced significant morphological and biophysical changes in endothelial cells, including increased surface roughness and height, without altering elastic modulus.
• Endorepellin triggered autophagic flux, evidenced by the co-localization of mammalian target of rapamycin (mTOR) with LC3-positive autophagosomes.
• Endorepellin's action was upstream of AMPKα, as its inhibition blocked endorepellin-induced autophagy.
• Both endorepellin and a known autophagy inducer (Torin 1) inhibited ex vivo angiogenesis.

Conclusions:

• Autophagy is a novel mechanism by which endorepellin exerts its anti-angiogenic effects.
• Endorepellin-induced angiostasis is independent of nutrient deprivation.
• These findings highlight endorepellin as a potential therapeutic agent targeting angiogenesis via autophagy modulation.