Proof-of-concept study: APOE4 brain endothelial cells as a phenotypic compound screen.

Area of Science:

• Neuroscience
• Pharmacology
• Cell Biology

Background:

• APOE4 genotype is linked to increased neurodegeneration risk, potentially due to higher cerebrovascular permeability.
• Brain endothelial cell APOE genotype influences cerebrovascular function, with APOE4 cells being more susceptible to dysfunction.
• This study explores therapeutic applications by identifying compounds that protect APOE4 brain endothelial cells.

Purpose of the Study:

• To establish and validate a phenotypic screening assay using APOE4 brain endothelial cells.
• To identify compounds that protect against lipopolysaccharide (LPS)-induced dysfunction in these cells.

Main Methods:

• Adapted an in vitro assay measuring trans endothelial cell electrical resistance (TEER) into a validated phenotypic screen.
• Scaled cell isolation protocols and optimized assay conditions (min, mid, max signals).
• Screened approximately 900 compounds from a bioactive library and validated hits in vivo.

Main Results:

• Identified 33 protective compounds, categorized by their effects on signaling pathways (growth factor receptor, intracellular signaling).
• Two main compound groups emerged: those disrupting cells (often inhibiting mTOR) and those protecting against LPS-induced TEER reduction.
• Four top compounds (Tadalafil, Vorinostat, CCT196969, SGI-7079) mitigated LPS-induced cerebrovascular dysfunction in APOE4 mice.

Conclusions:

• The developed in vitro screen effectively identifies compounds that prevent LPS-induced dysfunction in APOE4 brain endothelial cells.
• This assay holds potential for discovering novel therapeutics targeting APOE4-associated cerebrovascular issues.