Hypoxia Postconditioning Attenuates Hypoxia-Induced Inflammation and Endothelial Barrier Dysfunction

Area of Science:

• Cell Biology
• Physiology
• Biochemistry

Background:

• Hypoxia reoxygenation (HR) can cause endothelial barrier dysfunction and inflammation.
• P38 mitogen-activated protein kinase (P38 MAPK) activation contributes to endothelial barrier breakdown during HR.
• The specific effect of hypoxia postconditioning (HPC) on P38 MAPK in human dermal microvascular endothelial cells remains unclear.

Purpose of the Study:

• To investigate the protective function of HPC against HR-induced endothelial injury in human dermal microvascular endothelial cells.
• To determine the role of P38 MAPK signaling in HPC's protective effects.
• To examine the impact of HPC on endothelial barrier integrity and inflammatory markers.

Main Methods:

• Human dermal microvascular endothelial cells were subjected to hypoxia reoxygenation (HR) or hypoxia postconditioning (HPC).
• Cell activity, inflammatory cytokine levels (IL-6, IL-8, IL-1β), and endothelial barrier permeability were assessed.
• P38 MAPK activation (P-P38 MAPK), P38 MAPK expression, and claudin-5 levels and localization were analyzed using Western blot and immunofluorescence.

Main Results:

• HR led to increased endothelial hyperpermeability, inflammation, and P-P38 MAPK levels.
• HPC treatment significantly reduced cell injury and maintained endothelial barrier integrity.
• HPC inhibited P-P38 MAPK, increased claudin-5 expression, and promoted its continuous localization on the cell membrane.

Conclusions:

• HPC demonstrates a protective effect against hypoxia reoxygenation-induced endothelial barrier dysfunction.
• The mechanism involves the inhibition of P38 MAPK signaling pathway.
• HPC preserves endothelial barrier integrity by modulating claudin-5 expression and localization.