Integrated Chinese and Western Medicine Postdoctoral Research Station, Jinan University, Guangzhou, China.
International Ocular Surface Research Center and Institute of Ophthalmology, Jinan University Medical School, Guangzhou, China.
Mucosal Immunol. 2017 Sep;10(5):1145-1159. doi: 10.1038/mi.2016.139. Epub 2017 Jan 25.
Macrophages are distributed throughout the body and are crucial for the restoration of damaged tissues. However, their characteristics in the cornea and roles in the repair of corneal injures are unclear. Here we show that corneal macrophages can be classified as CCR2 macrophages, which already exist in the cornea at embryonic day 12.5 (E12.5) and are similar to yolk sac-derived macrophages, microglia, in phenotype and gene expression, and CCR2 macrophages, which do not appear in the cornea until E17.5. At a steady state, CCR2 corneal macrophages have local proliferation capacity and are rarely affected by monocytes; however, following corneal epithelial abrasion, most CCR2 corneal macrophages are replaced by monocytes. In contrast, CCR2 macrophages are repopulated by monocytes under both a steady-state condition and following corneal wounding. Depletion of CCR2 macrophages decreases corneal inflammation after epithelial abrasion, whereas depletion of CCR2 macrophages increases inflammation of the injured cornea. Loss of either cell type results in a delay in corneal healing. These data indicate that there are two unique macrophage populations present in the cornea, both of which participate in corneal wound healing by balancing the inflammatory response.
巨噬细胞分布于全身，对于受损组织的修复至关重要。然而，它们在角膜中的特征以及在角膜损伤修复中的作用尚不清楚。在这里，我们发现角膜巨噬细胞可分为 CCR2 巨噬细胞，这些细胞在胚胎第 12.5 天（E12.5）就已经存在于角膜中，其表型和基因表达与卵黄囊来源的巨噬细胞和小神经胶质细胞相似，而 E17.5 时才出现 CCR2 表达的角膜巨噬细胞。在稳态下，CCR2 角膜巨噬细胞具有局部增殖能力，很少受单核细胞影响；然而，在角膜上皮磨损后，大多数 CCR2 角膜巨噬细胞被单核细胞取代。相反，在稳态和角膜损伤后，CCR2 巨噬细胞通过单核细胞重新填充。CCR2 巨噬细胞耗竭可减少上皮磨损后的角膜炎症，而 CCR2 巨噬细胞耗竭则增加损伤角膜的炎症。这两种细胞类型的缺失都会导致角膜愈合延迟。这些数据表明，角膜中存在两种独特的巨噬细胞群体，它们通过平衡炎症反应参与角膜伤口愈合。
