Perivascular Macrophages Convert Physical Wound Signals Into Rapid Vascular Responses

Area of Science:

• Vascular biology
• Immunology
• Cellular signaling

Background:

• Leukocytes rapidly detect distant wounds, crucial for defense and healing.
• The mechanism for immediate blood vessel wound detection is unknown.
• Rapid vascular response is needed to initiate leukocyte extravasation.

Purpose of the Study:

• To investigate how blood vessels achieve rapid wound detection.
• To elucidate the molecular mechanisms linking wound signals to vascular responses.

Main Methods:

• High-speed live imaging of zebrafish larvae.
• Genetic, pharmacologic, and osmotic perturbations.
• Chemogenetic leukocyte depletion.

Main Results:

• Perivascular macrophages sense osmotic wound signals via the cPla2 pathway.
• These macrophages generate a 5-lipoxygenase (Alox5a)-derived lipid.
• This lipid mediates rapid vessel dilation and serum exudation within seconds of injury.

Conclusions:

• Perivascular macrophages act as physicochemical relays for wound detection.
• They bridge osmotic signals and vascular responses, enabling rapid injury management.
• This study uncovers a novel communication pathway coordinating immune and vascular systems.