Macrophage morphological plasticity and migration is Rac signalling and MMP9 dependant

Sci Rep. 2021 May 12;11(1):10123. doi: 10.1038/s41598-021-88961-7.


In vitro, depending on extracellular matrix (ECM) architecture, macrophages migrate either in amoeboid or mesenchymal mode; while the first is a general trait of leukocytes, the latter is associated with tissue remodelling via Matrix Metalloproteinases (MMPs). To assess whether these stereotyped migrations could be also observed in a physiological context, we used the zebrafish embryo and monitored macrophage morphology, behaviour and capacity to mobilise haematopoietic stem/progenitor cells (HSPCs), as a final functional readout. Morphometric analysis identified 4 different cell shapes. Live imaging revealed that macrophages successively adopt all four shapes as they migrate through ECM. Treatment with inhibitors of MMPs or Rac GTPase to abolish mesenchymal migration, suppresses both ECM degradation and HSPC mobilisation while differently affecting macrophage behaviour. This study depicts real time macrophage behaviour in a physiological context and reveals extreme reactivity of these cells constantly adapting and switching migratory shapes to achieve HSPCs proper mobilisation.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cell Movement* / drug effects
  • Cell Plasticity*
  • Fluorescent Antibody Technique
  • Humans
  • Macrophages / cytology*
  • Macrophages / drug effects
  • Macrophages / metabolism*
  • Matrix Metalloproteinase 9 / metabolism*
  • Matrix Metalloproteinase Inhibitors / pharmacology
  • Signal Transduction* / drug effects
  • Zebrafish
  • rac GTP-Binding Proteins / metabolism*


  • Matrix Metalloproteinase Inhibitors
  • Matrix Metalloproteinase 9
  • rac GTP-Binding Proteins