Pigment epithelium-derived factor in the monkey retinal pigment epithelium and interphotoreceptor matrix: apical secretion and distribution
Pigment epithelium-derived factor in the monkey retinal pigment epithelium and interphotoreceptor matrix: apical secretion and distribution
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DOI：
10.1016/j.exer.2003.10.013
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发表时间：
2004-02-01
影响因子：
3.4
通讯作者：
Pfeffer, BA
中科院分区：
文献类型：
--
作者：
Becerra, SP;Fariss, RN;Pfeffer, BA
色素上皮衍生因子（PEDF）是一种来源于视网膜色素上皮（RPE）的细胞外蛋白，RPE是一种由极化细胞形成的组织，以定向方式释放生长和营养因子。我们研究了PEDF蛋白在猴视网膜色素上皮的分布和定向释放。我们建立了表达PEDF基因的猴RPE细胞的原代培养物，并合成和分泌PEDF蛋白。RPE培养物和猴眼组织的北方分析显示，与其他几种猴眼组织相比，PEDF转录物在RPE中高度表达，在培养的细胞中甚至比它们在天然RPE中更丰富。体外培养的RPE细胞分泌的蛋白具有PEDF的免疫学、生化学和生物学特性。培养8天后，RPE条件培养基中的总PEDF水平达到6.5 mg/ml（-）（即每个RPE细胞1.1 pg PEDF）。将RPE细胞在可渗透的支持物上培养为单层，在顶室和基底室之间形成屏障。在18个周期中，以三天或四天的间隔对顶端和基础培养基进行取样，并对PEDF含量进行定量。在最初的恢复时间间隔，大多数PEDF蛋白在顶端培养基中显著高于在基础培养基中（>4倍），在后面的时间间隔仅在顶端培养基中检测到。在原生猴眼中，感光细胞间基质中可溶性PEDF的浓度（144 nM）分别是玻璃体和水相中的7倍和25倍。PEDF是丰富的视杆细胞和视锥细胞外节周围的interphotoreceptor基质，并在较低的水平，通过共聚焦显微镜可视化的RPE检测。我们的结论是，PEDF合成的RPE分泌优先从顶端表面和顶端分布的RPE接壤的光感受器的外节。PEDF可作为RPE极化和分化的有用标志物。RPE的极化可能是控制PEDF分泌的重要机制，我们的研究结果为PEDF的调控提供了有趣的可能性。(C)2004 Elsevier Ltd.保留所有权利。
Pigment epithelium-derived factor (PEDF) is an extracellular protein derived from the retinal pigment epithelium (RPE), a tissue formed by polarized cells that release growth and trophic factors in a directional fashion. We have investigated the distribution and directional release of PEDF protein by the monkey RPE. We established primary cultures of monkey RPE cells that expressed the PEDF gene, and that synthesized and secreted the PEDF protein. Northern analysis of RPE cultures and monkey ocular tissues showed that PEDF transcripts were highly expressed in RPE as compared with several other monkey ocular tissues, being even more abundant in cultured cells than they were in the native RPE. The differentiated RPE cells in culture secreted protein that shared the immunological, biochemical and biological characteristics of PEDF. The overall PEDF levels in the RPE conditioned media reached 6.5 mg ml(-) after 8 days in culture (i.e. 1.1 pg of PEDF per RPE cell). RPE cells were cultivated on permeable supports as monolayers forming a barrier between apical and basal compartments. Apical and basal culture media were sampled at three or four-day intervals for 18 cycles, and the PEDF content was quantified. Most of the PEDF protein was significantly higher in the apical than in the basal medium (>4 times) at the initial recovery intervals, to be detected only in the apical medium at the latter intervals. In the native monkey eye, the concentration of soluble PEDF in the interphotoreceptor matrix (144 nM) was 7-fold and 25-fold greater than in vitreous and aqueous, respectively. PEDF was abundant in the interphotoreceptor matrix surrounding rod and cone outer segments, and was detectable at lower levels in the RPE as visualized by confocal microscopy. We concluded that PEDF synthesized by the RPE is secreted preferentially from the apical surface and is distributed apically to the RPE bordering the outer segments of photoreceptors. PEDF can be a useful marker for RPE polarization and differentiation. The polarization of RPE may be an important mechanism to control PEDF secretion and our results offer interesting possibilities on regulation of PEDF. (C) 2004 Elsevier Ltd. All rights reserved.