Dynamic and functional changes in vascular endothelial cell monolayers under combined hypoxic and inflammatory...

Area of Science:

• * Cellular and Molecular Biology
• * Physiology
• * Pathophysiology

Background:

• * Sepsis is characterized by dysregulated inflammation, microthrombi, and organ hypoxia.
• * Endothelial cell (EC) responses to inflammation are known, but combined hypoxia and inflammation effects are unclear.
• * Understanding EC behavior under these combined stressors is crucial for sepsis pathophysiology.

Purpose of the Study:

• * To investigate endothelial cell (EC) dynamics and function under simultaneous hypoxia and lipopolysaccharide (LPS) exposure.
• * To elucidate the interplay between hypoxia-inducible factor 1-alpha (HIF-1α) and nuclear factor-kappa B (NF-κB) signaling pathways.
• * To model sepsis-related EC changes using advanced microfluidic technology.

Main Methods:

• * Utilized microfluidic devices to control oxygen concentration and simulate hypoxic conditions.
• * Quantified collective cell migration using particle image velocimetry.
• * Assessed monolayer permeability via fluorescent dextran diffusion and measured adhesion molecule expression.

Main Results:

• * Hypoxia decreased EC migration speed, but LPS attenuated this effect, suggesting modulation of hypoxic responses.
• * Both hypoxia and LPS increased EC permeability; LPS preconditioning showed partial suppression.
• * LPS increased ICAM-1 and VCAM-1 expression, with VCAM-1 altered under hypoxia, indicating complex pathway crosstalk.
• * NF-κB inhibition significantly reduced collective migration and permeability.

Conclusions:

• * Combined hypoxia and LPS exposure induce complex phenotypic alterations in endothelial cells.
• * The NF-κB pathway plays a critical role in mediating EC migration and permeability changes under these conditions.
• * This in vitro model effectively recapitulates key aspects of sepsis-induced EC dysfunction, offering insights into therapeutic targets.