Drosophila complement-like Mcr acts as a wound-induced inflammatory chemoattractant

Area of Science:

• Immunology
• Developmental Biology
• Genetics

Background:

• Sterile tissue injury triggers an acute inflammatory response involving innate immune cell migration.
• The fruit fly Drosophila is a powerful model for studying inflammatory cell migration in vivo using live microscopy and genetics.
• The precise identity and function of early chemotactic signals driving immune cell recruitment remain largely unknown.

Purpose of the Study:

• To identify early wound-induced chemotactic signals responsible for immune cell recruitment in Drosophila.
• To elucidate the mechanisms by which these signals mediate inflammatory cell migration in vivo.
• To develop a predictive model of immune cell migration dynamics.

Main Methods:

• Utilized Drosophila genetics and live time-lapse microscopy.
• Employed mathematical modeling to analyze cell migration dynamics.
• Investigated the role of macroglobulin complement-related (Mcr) in wound healing.

Main Results:

• Identified the fly complement ortholog, macroglobulin complement-related (Mcr), as an early, wound-induced chemotactic signal.
• Demonstrated that epithelial-specific knockdown of Mcr suppresses macrophage recruitment to wounds.
• Combined mathematical modeling with genetic manipulation to understand macrophage migration.

Conclusions:

• Mcr is a crucial chemoattractant for inflammatory immune cells at injury sites in Drosophila.
• Mcr functions alongside hydrogen peroxide to ensure a rapid and efficient immune response to damage.
• This study reveals a novel function for Mcr, paralleling the role of mammalian complement component C5a.