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Updated: Mar 28, 2026
A Microphysiological System to Study Leukocyte-Endothelial Cell Interaction during Inflammation
Published on: December 9, 2021
IL-1α-induced microvascular endothelial cells promote neutrophil killing by increasing MMP-9 concentration and
Xiaoye Liu1,2, Hong Dong3, Mingming Wang1
1Beijing Traditional Chinese Veterinary Engineering Center and Beijing Key Laboratory of Traditional Chinese Veterinary Medicine, Beijing University of Agriculture, No.7 BeiNong Road, Changping, Beijing, 102206, China.
Abstract:
The recruitment of neutrophils by endothelial cells during infection has been extensively studied, but little is known about the regulation of neutrophils activity by endothelial cells. To examine the role of microvascular endothelial cells in neutrophil killing, we established a transmigration model using rat intestinal microvascular endothelial cells (RIMVECs) and measured the extracellular and intracellular killing of Escherichia coli, Lactobacillus acidophilus, and Staphylococcus aureus by transendothelial neutrophils. We observed that blood neutrophils engulfed bacteria but did not kill them, and lipopolysaccharide- or hemolysin-injured RIMVECs inhibited the extracellular and intracellular bactericidal activity of transendothelial neutrophils. In comparison, interleukin-1α-induced RIMVECs promoted the extracellular and intracellular killing activity of transendothelial neutrophils and significantly increased MMP-9 concentration and lysozyme activity in transendothelial neutrophils (p < 0.01 and p < 0.001, respectively). Our results demonstrated that activation of endothelial cells enhanced bactericidal activity of transendothelial neutrophils and bacterial toxin damage of endothelial cells led to reduction in bactericidal activity of transendothelial neutrophils. These findings offered new insight into the role of endothelial cells in the bactericidal activity of neutrophils.
Insights
Endothelial cells regulate neutrophil antimicrobial activity. Activated endothelial cells enhance neutrophil killing of bacteria, while damaged cells reduce it, offering new insights into infection control.
Area of Science:
- Immunology
- Cell Biology
- Microbiology
Background:
- Neutrophil recruitment by endothelial cells is well-studied.
- The regulation of neutrophil activity by endothelial cells remains unclear.
Purpose of the Study:
- To investigate the role of microvascular endothelial cells in neutrophil bactericidal activity.
- To determine how endothelial cell activation and injury affect neutrophil killing of bacteria.
Main Methods:
- Established a transmigration model using rat intestinal microvascular endothelial cells (RIMVECs).
- Assessed extracellular and intracellular killing of Escherichia coli, Lactobacillus acidophilus, and Staphylococcus aureus by transendothelial neutrophils.
- Measured MMP-9 concentration and lysozyme activity.
Main Results:
- Transmigrated neutrophils engulfed bacteria but showed limited killing.
- Lipopolysaccharide- or hemolysin-injured RIMVECs inhibited neutrophil bactericidal activity.
- Interleukin-1α-activated RIMVECs promoted neutrophil killing and increased MMP-9 and lysozyme activity.
Conclusions:
- Endothelial cell activation enhances transendothelial neutrophil bactericidal capacity.
- Bacterial toxin-induced endothelial cell damage impairs neutrophil antimicrobial function.
- Endothelial cells play a crucial regulatory role in neutrophil-mediated host defense against bacterial infections.
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