Endothelial Cell Transition: Preliminary Data on Cross-Organ Shift from Brain to Liver

Area of Science:

• Vascular Biology
• Cell Biology
• Biochemistry

Background:

• Endothelial cells (EC) are vital for vascular homeostasis and respond to pathological stimuli.
• Hepatocyte growth factor (HGF) has a complex role in vascular barrier function, with its effects on endothelial cells being poorly understood.
• This study investigates the impact of high HGF concentrations on mouse brain endothelial cells (MBECs).

Purpose of the Study:

• To examine how supraphysiological HGF concentrations affect MBEC integrity and morphology.
• To analyze the alterations in tight junction protein ZO-1 and endothelial marker von Willebrand factor (vWf) expression and localization.
• To assess the functional impact on the MBEC barrier using TEER and TEDP assays.

Main Methods:

• MBECs were cultured and treated with HGF (4 µL/mL) at early (p5) and late (p41) passages.
• Morphological changes were observed using brightfield microscopy.
• Protein expression and localization of ZO-1 and vWf were analyzed via Western blotting, immunocytochemistry, and confocal microscopy.
• Intercellular barrier function was measured using Transendothelial Electric Resistance (TEER) and Transendothelial Dextran Permeability (TEDP) assays.

Main Results:

• HGF treatment induced morphological changes in MBECs, shifting from spindle-like to spheroid shapes.
• Western blotting showed a decrease in ZO-1 expression in HGF-treated cells, while vWf expression remained unchanged.
• Immunocytochemistry and confocal microscopy revealed disrupted ZO-1 localization, with a shift from membrane-associated to diffuse cytoplasmic patterns, and disorganization of the actin cytoskeleton.
• TEER values significantly decreased, and TEDP increased, indicating compromised barrier function.

Conclusions:

• Supraphysiological HGF disrupts the organization of tight junctions (TJs) in MBECs.
• This disruption leads to morphological alterations and functional weakening of the endothelial barrier.
• The study highlights the uncoupling of ZO-1 and the F-actin cytoskeleton, reduced barrier resistance, and increased paracellular permeability under high HGF conditions.