Murataeva Natalia, Daily Laura, Taylor Xavier, Dhopeshwarkar Amey, Hu Sherry Shu-Jung, Miller Sally, McHugh Douglas, Oehler Olivia, Li Shimin, Bonanno Joseph A, Mackie Ken, Straiker Alex
The Gill Center for Biomolecular Science and the Department of Psychological and Brain Sciences, Indiana University, Bloomington, IN.
Department of Psychology, National Cheng Kung University, Tainan, Taiwan.
Cornea. 2019 Jul;38(7):905-913. doi: 10.1097/ICO.0000000000001934.
We previously showed that cannabinoid-related GPR18 receptors are present in the murine corneal epithelium, but their function remains unknown. The related CB1 receptors regulate corneal healing, possibly via chemotaxis. We therefore examined a potential role for GPR18 in corneal epithelial chemotaxis and wound healing.
We examined GPR18 messenger RNA (mRNA) and protein expression in the cornea. We additionally examined GPR18 action in cultured bovine corneal epithelial cells (bCECs) using Boyden and tracking assays, as well as proliferation and signaling. Finally, we examined wound closure in murine corneal explants.
GPR18 mRNA was upregulated with injury in the mouse cornea. GPR18 protein was present in basal epithelial cells of the mouse and cow and redistributed to the wound site upon injury. GPR18 ligand N-arachidonoylglycine induced bCEC chemotaxis. The endocannabinoid arachidonoylethanolamine also induced chemotaxis via fatty acid amide hydrolase-mediated metabolism to N-arachidonoylglycine. GPR18 receptor activation additionally induced bCEC proliferation. In an explant model, the GPR18 antagonist O-1918 slowed corneal epithelial cell migration and the rate of corneal wound closure.
Corneal GPR18 activation induced both chemotaxis and proliferation in corneal epithelial cells in vitro and impacted wound healing. GPR18 may contribute to the maintenance of corneal integrity.
我们之前发现大麻素相关的GPR18受体存在于小鼠角膜上皮中，但其功能仍不清楚。相关的CB1受体可能通过趋化作用调节角膜愈合。因此，我们研究了GPR18在角膜上皮趋化和伤口愈合中的潜在作用。
我们检测了角膜中GPR18信使核糖核酸（mRNA）和蛋白质的表达。我们还使用博伊登实验和追踪实验检测了GPR18在培养的牛角膜上皮细胞（bCEC）中的作用，以及细胞增殖和信号传导。最后，我们检测了小鼠角膜外植体的伤口闭合情况。
GPR18 mRNA在小鼠角膜损伤时上调。GPR18蛋白存在于小鼠和牛的基底上皮细胞中，损伤后重新分布到伤口部位。GPR18配体N-花生四烯酰甘氨酸诱导bCEC趋化。内源性大麻素花生四烯酸乙醇胺也通过脂肪酸酰胺水解酶介导的代谢转化为N-花生四烯酰甘氨酸来诱导趋化。GPR18受体激活还诱导bCEC增殖。在一个外植体模型中，GPR18拮抗剂O-1918减缓了角膜上皮细胞迁移和角膜伤口闭合速度。
角膜GPR18激活在体外诱导角膜上皮细胞趋化和增殖，并影响伤口愈合。GPR18可能有助于维持角膜完整性。
