Department of Ophthalmology & Visual Sciences, The Chinese University of Hong Kong, Hong Kong, China; Beijing Institute of Ophthalmology, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing Ophthalmology and Visual Sciences Key Laboratory, Beijing, China; Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing Ophthalmology and Visual Sciences Key Laboratory, Beijing, China.
Tissue Engineering and Stem Cell Group, Singapore Eye Research Institute, Singapore.
Exp Eye Res. 2018 Apr;169:149-156. doi: 10.1016/j.exer.2018.01.015. Epub 2018 Jan 31.
The pathogenesis of pterygium has been linked to limbal stem cell damage, abnormal apoptosis and cellular proliferation. In this study, we investigated the epigenetic regulation through microRNA expression in the pathogenesis of pterygium.
Human full-length primary pterygia were microdissected into head and body regions. Specific microRNA and mRNA expression was assayed by TaqMan real-time quantitative polymerase chain reaction (qPCR). Tissue localization of target microRNAs was performed by LNA-based in situ hybridization. MicroRNA-145 (miR-145) mimics were transfected to primary culture of human pterygial cells, followed by analyses of cell cycle changes, apoptosis, p53 and MDM2 expression using flow cytometry and qPCR.
The expression of miR-145 was markedly higher in primary human pterygium than in limbus and conjunctiva. Both miR-143 and miR-145 were predominantly expressed in the basal pterygial epithelium. Oncogene MDM2 expression was abundant in pterygial epithelium and stroma, while the expression pattern was opposite to that of miR-145. Ectopic expression of miR-145 in pterygial cells induced G1 arrest, down-regulated MDM2 and elevated p53 expression.
Our study showed that miR-145 suppressed MDM2 expression, which subsequently influenced the p53-related cell growth pattern in pterygial epithelium. The regulatory miR-145/MDM2-p53 loop can serve as a potential target for treatment of pterygium.
翼状胬肉的发病机制与角膜缘干细胞损伤、异常凋亡和细胞增殖有关。本研究通过 microRNA 表达探讨翼状胬肉发病机制中的表观遗传调控。
将人全长原发性翼状胬肉细分为头部和体部。通过 TaqMan 实时定量聚合酶链反应（qPCR）检测特定的 microRNA 和 mRNA 表达。采用基于 LNA 的原位杂交技术检测靶 microRNA 的组织定位。将 microRNA-145（miR-145）模拟物转染至人翼状胬体原代培养细胞，然后通过流式细胞术和 qPCR 分析细胞周期变化、细胞凋亡、p53 和 MDM2 表达。
miR-145 在原发性人翼状胬肉中的表达明显高于角膜缘和结膜。miR-143 和 miR-145 主要在翼状胬状上皮的基底层表达。癌基因 MDM2 在翼状胬状上皮和基质中的表达丰富，而表达模式与 miR-145 相反。在翼状胬状细胞中异位表达 miR-145 可诱导 G1 期阻滞，下调 MDM2 并上调 p53 表达。
本研究表明，miR-145 抑制 MDM2 表达，进而影响翼状胬状上皮中的 p53 相关细胞生长模式。调节 miR-145/MDM2-p53 环可作为治疗翼状胬肉的潜在靶点。
