Progranulin Increases Phagocytosis by Retinal Pigment Epithelial Cells in Culture
Progranulin Increases Phagocytosis by Retinal Pigment Epithelial Cells in Culture
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DOI：
10.1002/jnr.24081
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发表时间：
2017-12-01
影响因子：
4.2
通讯作者：
Hara, Hideaki
中科院分区：
文献类型：
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作者：
Murase, Hiromi;Tsuruma, Kazuhiro;Hara, Hideaki
视网膜色素上皮(RPE)细胞每天都参与视网膜的保存，如吞噬脱落的光感受器外节(POS)。吞噬功能的不完全加速了RPE的退化和有毒副产物脂褐素的形成。脂褐素过度积聚是人类眼部各种致盲疾病的特征。原颗粒蛋白是一种富含半胱氨酸的蛋白质，具有多种生物活性，在视网膜中含量很高。原颗粒蛋白已被认为与脑内巨噬细胞吞噬功能有关。本研究的目的是确定原颗粒是否影响RPE细胞的吞噬功能。所有实验均在原代培养的人RPE(HRPE)细胞上进行。用pHrodo标记分离的猪POS，用pHrodo荧光定量测定吞噬程度。采用Western blotting和免疫组织化学方法对吞噬过程中的关键蛋白进行分析，以阐明原颗粒的作用机制。原颗粒增强过氧化氢处理和未处理的RPE细胞的RPE吞噬功能。在原颗粒蛋白暴露的细胞中，对POS内化起重要作用的Mer酪氨酸激酶的磷酸化形式显著增加。这种增加可被肝生长因子受体抑制剂SU11274减弱。在氧化应激条件下，PRO颗粒导致整合素α-v增加近两倍，这与RPE细胞识别POS的第一步有关。提示原颗粒可能是一种有效的RPE吞噬刺激因子，对RPE功能具有修复作用。(C)2017威利期刊公司。
Retinal pigment epithelium (RPE) cells take part in retinal preservation, such as phagocytizing the shed photoreceptor outer segments (POS), every day. The incomplete phagocytic function accelerates RPE degeneration and formation of the toxic by-product lipofuscin. Excessive lipofuscin accumulation is characteristic of various blinding diseases in the human eye. Progranulin is a cysteine-rich protein that has multiple biological activities, and it has a high presence in the retina. Progranulin has been recognized to be involved in macrophage phagocytosis in the brain. The purpose of this study is to determine whether progranulin influences phagocytosis by RPE cells. All experiments were performed on primary human RPE (hRPE) cells in culture. pHrodo was used to label the isolated porcine POS, and quantification of pHrodo fluorescence was used to determine the degree of phagocytosis. Western blotting and immunohistochemistry of key proteins involved in phagocytosis were used to clarify the mechanism of progranulin. Progranulin increased RPE phagocytosis in hydrogen peroxide-treated and nontreated RPE cells. The phosphorylated form of Mer tyrosine kinase, which is important for POS internalization, was significantly increased in the progranulin-exposed cells. This increase was attenuated by SU11274, an inhibitor of hepatic growth factor receptor. Under the oxidative stress condition, exposure to progranulin led to an approximately twofold increase in integrin alpha-v, which is associated with the first step in recognition of POS by RPE cells. These results suggest that progranulin could be an effective stimulator for RPE phagocytosis and could repair RPE function. (C) 2017 Wiley Periodicals, Inc.