5,6-DiHETE attenuates vascular hyperpermeability by inhibiting Ca²⁺ elevation in endothelial cells

Area of Science:

• Vascular biology
• Lipid metabolism
• Inflammation research

Background:

• Over 100 lipid metabolites exist, but their functions are largely unknown.
• Intestinal lipid metabolite production changes significantly during colitis.
• 5,6-dihydroxyeicosatetraenoic acid (DiHETE) exhibits anti-inflammatory properties in the vasculature.

Purpose of the Study:

• To investigate the vascular mechanisms of lipid metabolites, focusing on 5,6-DiHETE.
• To determine how 5,6-DiHETE affects histamine-induced inflammatory responses in endothelial cells.
• To elucidate the role of intracellular calcium signaling in 5,6-DiHETE's vascular activity.

Main Methods:

• Utilized mouse models and human umbilical vein endothelial cells (HUVECs).
• Administered 5,6-DiHETE and histamine to assess inflammatory reactions, vascular dilation, and hyperpermeability.
• Measured vascular contraction, relaxation, nitric oxide (NO) production, and intracellular calcium concentrations.

Main Results:

• 5,6-DiHETE did not induce inflammation but inhibited histamine-induced vascular dilation and hyperpermeability in mouse ears.
• In HUVECs, 5,6-DiHETE prevented histamine-induced barrier disruption and reduced NO production.
• Crucially, 5,6-DiHETE suppressed histamine-induced increases in intracellular calcium levels in HUVECs.

Conclusions:

• 5,6-DiHETE attenuates vascular hyperpermeability by inhibiting endothelial calcium elevation during inflammation.
• These findings suggest 5,6-DiHETE as a potential therapeutic agent for inflammatory diseases.
• Targeting endothelial calcium signaling offers a novel pharmacological strategy against vascular inflammation.