Sided Stimulation of Endothelial Cells Modulates Neutrophil Trafficking in an In Vitro Sepsis Model

Area of Science:

• Cell Biology
• Immunology
• Biomedical Engineering

Background:

• Dysregulated polymorphonuclear leukocyte (PMN) transmigration is a key factor in sepsis-mediated tissue damage.
• Current therapeutic strategies to control aberrant transmigration remain limited.
• Microphysiological systems (MPS) offer advanced in vitro models for studying human diseases, including endothelial physiology.

Purpose of the Study:

• To evaluate the role of endothelial cell (EC) apicobasal polarity in leukocyte trafficking.
• To investigate PMN transmigration using a novel microphysiological system (µSiM-MVM).
• To model sepsis-like conditions and assess their impact on PMN behavior.

Main Methods:

• Utilized the µSiM-MVM, a microphysiological system with a silicon membrane, to mimic microvasculature.
• Stimulated endothelial cells (ECs) apically or basally with a cytokine cocktail to simulate a septic-like challenge.
• Introduced healthy donor PMNs to assess transmigration in response to different EC stimulation conditions and bacterial peptide chemoattractants.

Main Results:

• Basal EC stimulation resulted in a stronger PMN transmigratory response compared to apical stimulation.
• Apical EC stimulation with a septic-like challenge attenuated PMN chemotaxis, preventing migration towards bacterial chemoattractants.
• A five-fold increase in apical inflammatory stimulus was required to achieve high PMN transmigration levels.

Conclusions:

• Endothelial cell apicobasal polarity is a critical regulator of PMN transmigratory behavior.
• The findings provide novel insights into the mechanisms underlying sepsis-associated leukocyte trafficking.
• This study highlights the potential of MPS in dissecting complex cellular interactions in disease models.