Role for anions in pulmonary endothelial permeability

Area of Science:

• Cell biology
• Physiology
• Biophysics

Background:

• Beta-adrenergic stimulation impacts pulmonary endothelial cell permeability and morphology, mediated by chloride (Cl-) flux.
• Endothelial cell function is sensitive to extracellular ion concentrations, influencing barrier properties.

Purpose of the Study:

• To investigate how different extracellular anions affect endothelial permeability.
• To determine if anion-mediated changes in endothelial cells alter endothelial permeability.
• To elucidate the role of anion channels in regulating pulmonary endothelial barrier function.

Main Methods:

• Measured radiolabeled albumin permeation across bovine pulmonary arterial endothelial monolayers with various extracellular anions (Cl-, Br-, I-, F-, acetate, gluconate, propionate).
• Assessed the effect of 3-isobutyl-1-methylxanthine (IBMX) on albumin permeability.
• Utilized anion channel blockers (4-acetamido-4'-isothiocyanotostilbene-2,2'-disulfonic acid, anthracene-9-carboxylic acid) and anion transport blockers (bumetanide, furosemide).

Main Results:

• Extracellular anions significantly influenced endothelial permeability to albumin.
• Chloride (Cl-) demonstrated the greatest reduction in albumin permeability upon IBMX addition, indicating a specific role.
• Anion channel blockers altered permeability, while other anion transport blockers did not, suggesting involvement of anion channels.

Conclusions:

• Extracellular anions modulate pulmonary arterial endothelial permeability.
• The observed effects align with the activity of anion channels rather than other anion transport mechanisms.
• Chloride ions play a critical role in regulating endothelial barrier function, influenced by anion channel activity.