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. Csf1^op/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 Csf1^op/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.

组织巨噬细胞普遍存在于先天免疫细胞中，在发育和器官发生中起多种作用。在发育过程中，巨噬细胞会在神经元发育过程中修剪短暂或不必要的突触，并在血管发育过程中修剪血管，从而促进适当的组织重塑。在本研究中，我们确定巨噬细胞有助于瞳孔形态的发展。CSF1 ^{OP / OP}几乎没有眼巨噬细胞的突变小鼠表现出异常的瞳孔边缘，并且多余的虹膜组织异常突出进入瞳孔空间。位于瞳孔边缘附近的巨噬细胞吞噬了色素残渣，这些碎片可能由不必要的虹膜突起组成，这些突起在瞳孔边缘变平滑期间出现。确实，瞳孔边缘巨噬细胞在表型上具有M2巨噬细胞的某些特征，与强大的组织吞噬和重塑活动相一致。有趣的是，仅在回归血管之间的间隙中检测到Csf1 ^{op / op}小鼠中突出的虹膜。综上所述，我们的发现揭示了眼巨噬细胞的新作用，表明该细胞群对于发育过程中的虹膜修剪很重要。