Bacterial-induced hepoxilin A3 secretion as a pro-inflammatory mediator

Area of Science:

• Immunology
• Molecular Biology
• Cell Biology

Background:

• Bacterial infections trigger neutrophil migration to epithelial surfaces.
• Chemoattractants from pathogen-stimulated cells orchestrate this immune response.
• A specific factor for neutrophil attraction across epithelia remained unidentified.

Purpose of the Study:

• To highlight recent findings on hepoxilin A(3) in mucosal inflammation.
• To establish hepoxilin A(3) as a key regulator of inflammatory responses.
• To elucidate the role of hepoxilin A(3) in neutrophil recruitment to epithelial surfaces.

Main Methods:

• Identification of hepoxilin A(3) secreted from stimulated human intestinal and lung epithelial cells.
• Investigation of hepoxilin A(3) function in guiding neutrophils across epithelial tight junctions.
• Analysis of the effects of interrupting the hepoxilin A(3) synthetic pathway on neutrophil transmigration in vitro and in vivo.

Main Results:

• Hepoxilin A(3) was identified as selectively secreted from epithelial cells upon stimulation with Salmonella Typhimurium or Pseudomonas aeruginosa.
• Hepoxilin A(3) functions to guide neutrophils by establishing a gradient across the epithelial tight junction complex.
• Interruption of hepoxilin A(3) synthesis blocked its apical release and neutrophil transmigration in models of inflammation.

Conclusions:

• Hepoxilin A(3) is a novel chemoattractant critical for neutrophil recruitment during bacterial infections at mucosal surfaces.
• The hepoxilin A(3) pathway represents a significant discovery in understanding mucosal inflammation.
• These findings have broad implications for inflammatory responses affecting the gut and lung epithelia.