Pyoverdine-induced iron dysregulation exacerbates vascular endothelial barrier dysfunction under hyperglycemic...

Area of Science:

• Vascular Biology
• Microbial Pathogenesis
• Diabetic Complications

Background:

• Diabetic foot infections (DFI) are a major cause of morbidity and mortality.
• Pseudomonas aeruginosa is a key pathogen in DFI, utilizing virulence factors like pyoverdine (PVD).
• The impact of PVD on endothelial barrier function, particularly under hyperglycemia, is not well understood.

Purpose of the Study:

• To investigate the effects of PVD and high glucose (HG) on human umbilical vein endothelial cells (HUVECs).
• To elucidate the mechanisms by which PVD compromises endothelial integrity.

Main Methods:

• Transcriptomic analysis (RNA-seq) of HUVECs exposed to PVD.
• In vitro functional assays measuring cell viability, ROS production, and mitochondrial function.
• Transmission electron microscopy for ultrastructural analysis.
• Assessment of transendothelial flux and tight junction protein expression.

Main Results:

• PVD altered gene expression in HUVECs, upregulating iron homeostasis genes and affecting ECM and barrier function pathways.
• PVD reduced cell viability, increased ROS, and damaged mitochondria.
• PVD impaired endothelial barrier integrity, evidenced by increased FITC-dextran flux and decreased ZO-1 and Claudin-5 expression.
• High glucose exacerbated PVD-induced damage.

Conclusions:

• PVD disrupts endothelial barrier function by interfering with iron homeostasis and inducing oxidative stress.
• PVD downregulates junctional proteins, compromising vascular integrity in DFI.
• Targeting iron metabolism and oxidative stress may offer therapeutic strategies for PVD-related vascular injury in DFI.