Macrophages fine-tune pupil shape during development

Dev Biol. 2020 Aug 15;464(2):137-144. doi: 10.1016/j.ydbio.2020.06.004. Epub 2020 Jun 18.


Tissue macrophages, which are ubiquitously present innate immune cells, play versatile roles in development and organogenesis. During development, macrophages prune transient or unnecessary synapses in neuronal development, and prune blood vessels in vascular development, facilitating appropriate tissue remodeling. In the present study, we identified that macrophages contributed to the development of pupillary morphology. Csf1op/op mutant mice, in which ocular macrophages are nearly absent, exhibited abnormal pupillary edges, with abnormal protrusions of excess iris tissue into the pupillary space. Macrophages located near the pupillary edge engulfed pigmented debris, which likely consisted of unnecessary iris protrusions that emerge during smoothening of the pupillary edge. Indeed, pupillary edge macrophages phenotypically possessed some features of M2 macrophages, consistent with robust tissue engulfment and remodeling activities. Interestingly, protruding irises in Csf1op/op mice were only detected in gaps between regressing blood vessels. Taken together, our findings uncovered a new role for ocular macrophages, demonstrating that this cell population is important for iris pruning during development.

Keywords: Angiogenesis; Dll4; Macrophage; Pupillary membrane; Retina; VEGF.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Macrophage Colony-Stimulating Factor / genetics
  • Macrophage Colony-Stimulating Factor / metabolism
  • Macrophages / cytology
  • Macrophages / metabolism*
  • Mice
  • Mice, Mutant Strains
  • Pupil*


  • CSF1 protein, mouse
  • Macrophage Colony-Stimulating Factor