Thrombospondin-1 in the trabecular meshwork:: localization in normal and glaucomatous eyes, and induction by TGF-β1 and dexamethasone in vitro
Thrombospondin-1 in the trabecular meshwork:: localization in normal and glaucomatous eyes, and induction by TGF-β1 and dexamethasone in vitro
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DOI：
10.1016/j.exer.2004.07.005
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发表时间：
2004-11-01
影响因子：
3.4
通讯作者：
Tamm, ER
中科院分区：
文献类型：
--
作者：
Flügel-Koch, C;Ohlmann, A;Tamm, ER
转化生长因子- β 2 （tgf - β 2）在原发性开角型青光眼（POAG）患者房水中升高，高水平的tgf - β 2被认为与POAG的发病机制有关。大多数tgf - β 2在眼睛中以潜伏的、无活性的形式存在，其体内激活的机制尚不清楚。由于血栓反应蛋白-1 （TSP-1）是体内最有效的tgf - β激活分子之一，我们研究了TSP-1在房水流出通路中的定位和表达。对8例正常人和17例青光眼供体进行TSP-1免疫组化。此外，还研究了Tsp-1（-/-）缺失小鼠和正常Tsp-1（+/+）小鼠的眼睛。通过逆转录聚合酶链反应和Northern印迹法检测新鲜小梁网（TM）、人和小鼠TM细胞中TSP-1 mRNA的表达。此外，对tgf - β和地塞米松培养后的TM细胞进行Northern和Western blot分析。在大多数眼睛中，TSP-1免疫标记主要出现在TM关节旁（筛状）部分的细胞外区域。在TM的角膜巩膜和膜部观察到一些局灶性染色。在6例青光眼患者（包括1例类固醇性青光眼）的眼睛中，TSP-1的免疫反应性明显增强，TM的所有区域都被阳性标记。在双标记实验中，TSP-1的染色与纤维连接蛋白或VI型胶原的染色不重叠。在新鲜和培养的TM细胞中均检测到TSP-1的rnRNA。tgf - β 1和地塞米松在TM细胞中孵育后，TSP-1的表达明显增加。TM中的TSP-1可能是房水中tgf - β的一种有效的局部内源性激活剂，并介导tgf - β和/或地塞米松对房水流出的任何局部影响。(C) 2004 Elsevier Ltd.版权所有。
Transforming growth factor-beta2 (TGF-beta2) is elevated in the aqueous humor of patients with primary open-angle glaucoma (POAG), and high levels of TGF-beta2 are thought to contribute to the pathogenesis of POAG. Most TGF-beta2 in the eye is present in a latent, inactive form and the mechanisms of its in vivo activation are unclear. Since thrombospondin-1 (TSP-1) is one of the most potent in vivo activating molecules of TGF-betas, we investigated the localization and expression of TSP-1 in the aqueous humor outflow pathways. TSP-1 immunohistochemistry was performed in the eyes of human donors (8 normal and 17 with glaucoma). In addition, the eyes of Tsp-1(-/-)-deficient mice and normal Tsp-1(+/+) mice were investigated. TSP-1 mRNA expression was assessed by reverse transcription-polymerase chain reaction and Northern blotting of RNA from fresh trabecular meshwork (TM), and human and mouse TM cells in vitro. In addition, Northern and Western blot analyses of TM cells after incubation with TGF-beta and dexamethasone were performed. In most of the eyes, TSP-1 immunolabeling was predominately observed in extracellular areas of the juxtacanalicular (cribriform) part of the TM. Some focal staining was observed in the corneoscleral and uveal parts of the TM. In the eyes of six glaucoma patients (including one with steroid-induced glaucoma), TSP-1 immunoreactivity was considerably more intense and all regions of the TM were positively labeled. In double labeling experiments, staining for TSP-1 did not overlap with that of fibronectin or type VI collagen. rnRNA for TSP-1 was detected in both fresh and cultured TM cells. Incubation of TM cells with TGF-beta1 and dexamethasone caused a marked increase in TSP-1 expression. TSP-1 in the TM might act as a potent local endogenous activator of TGF-betas in the aqueous humor and mediate any local effects of TGF-beta and/or dexamethasone on the outflow of aqueous humor. (C) 2004 Elsevier Ltd. All rights reserved.