The role of protein kinase C in modulation of aqueous humor outflow facility
The role of protein kinase C in modulation of aqueous humor outflow facility
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DOI：
10.1016/s0014-4835(02)00255-5
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发表时间：
2003-01-01
影响因子：
3.4
通讯作者：
Rao, PV
中科院分区：
文献类型：
--
作者：
Khurana, RN;Deng, PF;Rao, PV
通常与青光眼相关的眼内压升高被认为是由于小梁网（TM）功能受损而引起的。虽然TM和Schlemm氏管（SC）包括主要的路线，为房水流出，鲜为人知的是潜在的信号机制参与的调节水流出。基于对蛋白激酶C（PKC）在血管生物学中作用的认识，我们试图通过研究TM和SC细胞收缩和形态学特征的调节来了解PKC通路对流出功能的贡献。我们研究了PKC参与调节人TM和SC细胞中肌球蛋白轻链（MLC）磷酸化、肌动蛋白应力纤维形成和整合素-ECM粘连（局灶性粘连），并将这些变化与去核猪全眼灌注模型中测量的房水流出设施相关。PKC亚型（α和β）在TM和SC细胞和组织中的表达和分布分别通过Western blot和免疫组织化学分析证实。发现PKC的药理学激活剂（佛波醇-12-肉豆蔻酸酯-13-乙酸酯（PMA）和佛波醇-12，13-二丁酸酯（PDBu））和抑制剂（星形孢菌素和GF 109203 X）均诱导人TM和SC细胞中细胞形状（收缩和变圆）和细胞骨架组织的变化。虽然PMA和PDBu产生的肌动蛋白应力纤维和粘着斑的形成和MLC磷酸化的增加，PKC抑制剂，观察到诱导这些细胞中的对比效果。有趣的是，PDBU和GF 109203 X都引起灌注模型中的房水流出功能的增加。PKC抑制剂（GF 109203 X）使流出增加46%，而PKC激活剂（PDBu）仅使流出增加27%。这些结果表明，PKC可能通过调节MLC磷酸化，从而调节TM和SC细胞的形态和细胞骨架特征，在调节水流出设施中发挥重要作用。(C)2002爱思唯尔科技有限公司。保留所有权利。
The elevated intraocular pressure that is commonly associated with glaucoma is believed to arise due to impairment of trabecular meshwork (TM) function. Although the TM and Schlemm's canal (SC) comprise the major route for aqueous humor outflow, little is known about the potential signaling mechanisms involved in the regulation of aqueous outflow. Based on knowledge regarding the role of protein kinase C (PKC) in vascular biology, we sought to understand the contribution of the PKC pathway towards outflow function by studying the modulation of contractile and morphological characteristics of TM and SC cells. We investigated the involvement of PKC in regulation of myosin light chain (MLC) phosphorylation, formation of actin stress fibers and integrin-ECM adhesions (focal adhesions) in human TM and SC cells and correlated these changes with aqueous outflow facility measured in an enucleated porcine whole eye perfusion model. Expression and distribution of PKC isoforms (alpha and epsilon) in TM and SC cells and tissues was confirmed by Western blot and immunohistochemical analysis, respectively. Both, pharmacological activators (phorbol-12-myristate 13-acetate (PMA) and phorbol-12,13-dibutyrate (PDBu)) and inhibitors (staurosporine and GF109203X) of PKC were found to induce changes in cell shape (retraction and rounding up) and cytoskeletal organization in human TM and SC cells. While PMA and PDBu produced an increase in formation of actin stress fibers and focal adhesions and in MLC phosphorylation, PKC inhibitors were observed to induce contrasting effects in these cells. Intriguingly, both PDBU and GF109203X caused increases in aqueous outflow facility in the perfusion model. The PKC inhibitor (GF109203X) increased outflow by 46% while the PKC activator (PDBu) only increased outflow by 27%. These results suggest that PKC might play an important role in modulation of aqueous outflow facility by regulating MLC phosphorylation and thereby, the morphological and cytoskeletal characteristics of TM and SC cells. (C) 2002 Elsevier Science Ltd. All rights reserved.