Song Julia, Deng Pei-Feng, Stinnett Sandra S, Epstein David L, Rao P Vasantha
Department of Ophthalmology, Duke University School of Medicine, Durham, NC 27710, USA.
Invest Ophthalmol Vis Sci. 2005 Jul;46(7):2424-32. doi: 10.1167/iovs.04-0776.
To investigate the effects of cholesterol-lowering statin drugs on trabecular meshwork cellular properties and aqueous humor outflow.
Primary cell cultures of porcine trabecular meshwork (PTM) and ciliary body (PCB) were treated with either lovastatin or compactin, to determine the effects of statins on cell shape, actin cytoskeletal organization, and cell-extracellular matrix interactions (focal adhesions) by immunofluorescence staining. Changes in myosin light-chain (MLC) phosphorylation were evaluated by Western blot analysis. Changes in Rho GTPase content of membrane fractions from lovastatin-treated PTM cells were assessed by Western blot analysis. A constant-flow, organ-culture perfusion system was used to measure the effects of statins on aqueous humor outflow facility in the anterior segments of porcine eyes.
PTM and PCB cells treated with lovastatin or compactin exhibited dramatic changes in cell shape and cytoskeletal organization within 24 hours, consisting of cell rounding, actin depolymerization, and decreased focal adhesions. These effects were found to be reversible on supplementation with geranylgeranyl pyrophosphate. Both lovastatin and compactin decreased MLC phosphorylation in PTM and PCB cells. PTM cells treated with lovastatin exhibited marked decreases in membrane-bound Rho GTPase. In addition, perfusion of organ-cultured porcine eye anterior segments with 100 microM lovastatin for 96 hours caused a significant increase in aqueous humor outflow facility (110%) compared with control eyes, in a reversible manner.
This study demonstrates that the statin drugs lovastatin and compactin induce changes in cell shape and actin cytoskeletal organization and decrease MLC phosphorylation in PTM and PCB cells, all of which are events that are likely to lead to cellular and tissue relaxation. In addition, these effects of the statins appear to be mediated by inhibition of isoprenylation of the small GTP-binding proteins such as Rho GTPase. An important finding is that statins exert an ocular hypotensive response in an organ-culture perfusion model, indicating the potential for this class of drugs in glaucoma therapy.
研究降胆固醇他汀类药物对小梁网细胞特性及房水流出的影响。
用洛伐他汀或康帕丁处理猪小梁网（PTM）和睫状体（PCB）的原代细胞培养物，通过免疫荧光染色确定他汀类药物对细胞形状、肌动蛋白细胞骨架组织及细胞 - 细胞外基质相互作用（粘着斑）的影响。通过蛋白质印迹分析评估肌球蛋白轻链（MLC）磷酸化的变化。通过蛋白质印迹分析评估洛伐他汀处理的PTM细胞的膜组分中Rho GTP酶含量的变化。使用恒流器官培养灌注系统测量他汀类药物对猪眼前段房水流出易度的影响。
用洛伐他汀或康帕丁处理的PTM和PCB细胞在24小时内细胞形状和细胞骨架组织出现显著变化，包括细胞变圆、肌动蛋白解聚和粘着斑减少。发现补充香叶基香叶基焦磷酸后这些作用是可逆的。洛伐他汀和康帕丁均降低了PTM和PCB细胞中的MLC磷酸化。用洛伐他汀处理的PTM细胞膜结合的Rho GTP酶显著减少。此外，用100微摩尔/升洛伐他汀灌注器官培养的猪眼前段96小时，与对照眼相比，房水流出易度显著增加（110%），且呈可逆性。
本研究表明，他汀类药物洛伐他汀和康帕丁可诱导PTM和PCB细胞的细胞形状和肌动蛋白细胞骨架组织发生变化，并降低MLC磷酸化，所有这些都是可能导致细胞和组织松弛的事件。此外，他汀类药物的这些作用似乎是通过抑制小GTP结合蛋白如Rho GTP酶的异戊二烯化介导的。一个重要发现是他汀类药物在器官培养灌注模型中产生眼压降低反应，表明这类药物在青光眼治疗中的潜力。
