Guo Xiaoling, Zhu Deliang, Lian Ruiling, Han Yuting, Guo Yonglong, Li Zhijie, Tang Shibo, Chen Jiansu
Key Laboratory for Regenerative Medicine, Ministry of Education, Jinan University, Guangzhou 510632, China.
The Department of Ophthalmology, the First Clinical Medical College, Jinan University, Guangzhou 510632, China.
Exp Eye Res. 2016 Jun;147:37-49. doi: 10.1016/j.exer.2016.04.021. Epub 2016 Apr 26.
Age-related macular degeneration (AMD) is a leading cause of blindness among the aging population. Currently, replacement of diseased retinal pigment epithelium (RPE) cells with transplanted healthy RPE cells could be a feasible approach for AMD therapy. However, maintaining cell-cell contact and good viability of RPE cells cultured in vitro is difficult and fundamentally determines the success of RPE cell transplantation. This study was conducted to examine the role of Matrigel and Activin A (MA) in regulating cell-cell contact and anti-apoptotic activity in human RPE (hRPE) cells, as assessed by atomic force microscopy (AFM), scanning electron microscope (SEM), immunofluorescence staining, quantitative polymerase chain reaction (qPCR) analysis, Annexin V/propidium iodide (PI) analysis, mitochondrial membrane potential (△Ψ m) assays, intracellular reactive oxygen species (ROS) assays and Western blotting. hRPE cells cultured in vitro could maintain their epithelioid morphology after MA treatment over at least 4 passages. The contact of N-cadherin to the lateral cell border was promoted in hRPE cells at P2 by MA. MA treatment also enhanced the expression of tight junction-associated genes and proteins, such as Claudin-1, Claudin-3, Occludin and ZO-1, as well as polarized ZO-1 protein distribution and barrier function, in cultured hRPE cells. Moreover, MA treatment decreased apoptotic cells, ROS and Bax and increased △Ψ m and Bcl2 in hRPE cells under serum withdrawal-induced apoptosis. In addition, MA treatment elevated the protein expression levels of β-catenin and its target proteins, including Cyclin D1, c-Myc and Survivin, as well as the gene expression levels of ZO-1, β-catenin, Survivin and TCF-4, all of which could be down-regulated by the Wnt/β-catenin pathway inhibitor XAV-939. Taken together, MA treatment could effectively promote cell-cell contact and anti-apoptotic activity in hRPE cells, partly involving the Wnt/β-catenin pathway. This study will benefit the understanding of hRPE cells and future cell therapy.
年龄相关性黄斑变性(AMD)是老年人群失明的主要原因。目前,用移植的健康视网膜色素上皮(RPE)细胞替代病变的RPE细胞可能是一种可行的AMD治疗方法。然而,在体外培养中维持RPE细胞的细胞间接触和良好活力具有挑战性,并且从根本上决定了RPE细胞移植的成功与否。本研究旨在通过原子力显微镜(AFM)、扫描电子显微镜(SEM)、免疫荧光染色、定量聚合酶链反应(qPCR)分析、膜联蛋白V/碘化丙啶(PI)分析、线粒体膜电位(△Ψm)测定、细胞内活性氧(ROS)测定和蛋白质印迹法,研究基质胶和激活素A(MA)在调节人RPE(hRPE)细胞的细胞间接触和抗凋亡活性中的作用。体外培养的hRPE细胞在MA处理后至少传代4次仍能保持其上皮样形态。MA促进了第2代hRPE细胞中N-钙黏蛋白与细胞外侧边界的接触。MA处理还增强了培养的hRPE细胞中紧密连接相关基因和蛋白的表达,如Claudin-1、Claudin-3、闭合蛋白和ZO-1,以及极化的ZO-1蛋白分布和屏障功能。此外,在血清剥夺诱导的凋亡中,MA处理减少了hRPE细胞中的凋亡细胞、ROS和Bax,并增加了△Ψm和Bcl2。此外,MA处理提高了β-连环蛋白及其靶蛋白(包括细胞周期蛋白D1、c-Myc和生存素)的蛋白表达水平,以及ZO-1、β-连环蛋白、生存素和TCF-4的基因表达水平,而这些均可被Wnt/β-连环蛋白通路抑制剂XAV-939下调。综上所述,MA处理可有效促进hRPE细胞的细胞间接触和抗凋亡活性,部分涉及Wnt/β-连环蛋白通路。本研究将有助于对hRPE细胞的理解以及未来的细胞治疗。