p22 phox expression in macrophages regulates the neutrophil wound response. (A) Representative images of neutrophil wound recruitment with or without cyba MO in 3-dpf Tg(mpx:gfp) or Tg(mpx:cyba-gfp) 3-dpf larvae fixed 3 hpw. (B) Quantification of the number of neutrophils at the wound obtained in A. (C) Representative images of neutrophil and macrophage wound recruitment 3 hpw with or without cyba MO in Tg(mpx;mcherry) larvae that transiently express mpeg-gfp or mpeg:cyba-gfp (D) Quantification of the number of macrophages (left) and neutrophils (right) present at 3 hpw in 3-dpf larvae depicted in C. Ctrl, control. (n) = number of larvae. Horizontal lines indicate means. Error bars indicate SEM. *, P < 0.05; **, P < 0.01, two-tailed unpaired t test. The triangles indicate wound location. Bars, 50 µm. (E) Schematic representation of redox/SFK signaling in adjacent tissues that control leukocyte recruitment to wounds (left), resolution of inflammation, and wound regeneration (right). After tissue injury, hydrogen peroxide (H2O2) is released and triggers the activation of the SFK Lyn in neutrophils. We report here that macrophages also require hydrogen peroxide production for their directed migration and identify the pivotal role of NADPH oxidase and the SFK Yrk in macrophage chemotaxis and indirectly on neutrophil reverse migration.
