Yu Alice L, Lorenz Reinhard L, Haritoglou Christos, Kampik Anselm, Welge-Lussen Ulrich
Department of Ophthalmology, Ludwig-Maximilians-University, Munich, Germany.
Exp Eye Res. 2009 Mar;88(3):495-503. doi: 10.1016/j.exer.2008.10.028. Epub 2008 Nov 27.
Age-related macular degeneration (AMD) and artherosclerosis share common characteristics in their pathogenesis. In this study, we investigated the effects of lipoproteins like native (n)-LDL, oxidized (ox)-LDL and high-density lipoprotein (HDL) on advanced senescence, extracellular matrix accumulation, cell loss, and transforming growth factor-beta2 (TGF-beta2) expression in cultured human retinal pigment epithelial (RPE) cells. Primary human RPE cells were incubated with 10-100 microg/ml n-LDL, ox-LDL, and HDL for 24h. For determination of advanced senescence, beta-galactosidase staining was used. The induction of fibronectin (Fn), laminin alpha 1 (Laa1), and collagen type IV alpha 2 (Col4a2) mRNA was quantified by real-time PCR. Cell loss was investigated by live dead assay. Expression of TGF-beta2 was analyzed by real-time PCR and ELISA assays. Ox-LDL accelerated dose-dependently the onset of RPE senescence, whereas LDL and HDL had no effect. LDL and ox-LDL led to induced expression of Fn, Laa1 and Col4a2, whereas HDL had no influence. Incubation of RPE cells with 100 microg/ml ox-LDL induced marked cell death compared to untreated control cells. Expression of TGF-beta2 was dose-dependently increased by LDL and ox-LDL. LDL and ox-LDL induced cellular changes in RPE cells in vitro, which may resemble pathogenic events of AMD. These results may provide further information about the effects of LDL and ox-LDL in the human RPE and their potential role in the pathogenesis of AMD.
年龄相关性黄斑变性（AMD）和动脉粥样硬化在发病机制上具有共同特征。在本研究中，我们调查了天然（n）-低密度脂蛋白（LDL）、氧化（ox）-LDL和高密度脂蛋白（HDL）等脂蛋白对培养的人视网膜色素上皮（RPE）细胞衰老、细胞外基质积累、细胞丢失以及转化生长因子-β2（TGF-β2）表达的影响。将原代人RPE细胞与10 - 100μg/ml的n-LDL、ox-LDL和HDL孵育24小时。采用β-半乳糖苷酶染色法测定细胞衰老。通过实时定量PCR对纤连蛋白（Fn）、层粘连蛋白α1（Laa1）和IV型胶原α2（Col4a2）mRNA的诱导情况进行定量分析。通过死活细胞检测法研究细胞丢失情况。采用实时定量PCR和酶联免疫吸附测定法分析TGF-β2的表达。Ox-LDL呈剂量依赖性加速RPE细胞衰老的发生，而LDL和HDL则无此作用。LDL和ox-LDL可诱导Fn、Laa1和Col4a2的表达，而HDL则无影响。与未处理的对照细胞相比，用100μg/ml ox-LDL孵育RPE细胞可诱导明显的细胞死亡。LDL和ox-LDL可使TGF-β2的表达呈剂量依赖性增加。LDL和ox-LDL在体外诱导RPE细胞发生细胞变化，这可能类似于AMD的致病过程。这些结果可能为LDL和ox-LDL对人RPE细胞的影响及其在AMD发病机制中的潜在作用提供更多信息。
