The angiopoietin/tie-2 system regulates pericyte survival and recruitment in diabetic retinopathy
The angiopoietin/tie-2 system regulates pericyte survival and recruitment in diabetic retinopathy
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DOI：
10.1167/iovs.07-1206
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发表时间：
2008-05-01
影响因子：
4.4
通讯作者：
Boulton, Michael E.
中科院分区：
文献类型：
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作者：
Cai, Jun;Kehoe, Oksana;Boulton, Michael E.
目的.血管生成素（Angiopoietin，Ang）系统在血管稳定和病理性新生血管形成中起重要作用。该研究的假设是，除了调节内皮细胞的行为，血管生成素/Tie-2系统还调节与糖尿病视网膜病变相关的周细胞凋亡和/或血管成熟。通过ELISA、Western Blot分析和流式细胞术分析培养的视网膜周细胞中Tie-2的表达。通过Western印迹分析测定周细胞中的CD 13（氨肽酶N）表达，并且用Tie-2反义处理验证Ang作用。通过结晶紫摄取监测细胞增殖，并在刮伤中评估周细胞迁移。Annexin V-FITC流式细胞术用于定量周细胞增殖。Ang-1和Ang-2均上调周细胞表达功能活性的Tie-2受体（P < 0.05）。在经历TNF-α或高糖诱导的凋亡的周细胞中，Ang-1增加存活率（TNF-α P < 0.05;高糖P < 0.01），而Ang-2增加凋亡。在合成基质伤口愈合试验中，Ang-1以剂量依赖性方式增强CD 13表达（P < 0.05），并刺激周细胞迁移，这与F-肌动蛋白组织的变化有关。Tie-2反义核酸的加入证实了血管生成素通过Tie-2发挥作用。这些发现表明，Tie-2在周细胞中起作用，并可能通过调节周细胞损失和影响周细胞的激活状态和募集在糖尿病视网膜病变的进展中发挥重要作用。
PURPOSE. The angiopoietin (Ang) system plays an important role in vascular stabilization and pathologic neovascularization. The hypothesis for the study was that, in addition to modulating endothelial cell behavior, the angiopoietin/Tie-2 system also regulates the pericyte apoptosis and/or the vessel maturation associated with diabetic retinopathy.METHODS. Tie-2 expression in cultured retinal pericytes was analyzed by using ELISA, Western Blot analysis, and flow cytometry. CD13 (aminopeptidase N) expression in pericytes was determined by Western blot analysis and Ang effects verified with Tie-2 antisense treatment. Cell proliferation was monitored by crystal violet uptake, and pericyte migration was assessed in a scrape wound. Annexin V-FITC flow cytometry was used to quantify pericyte apoptosis.RESULTS. Pericytes expressed a functionally active Tie-2 receptor upregulated by both Ang-1 and -2 (P < 0.05). In pericytes undergoing apoptosis induced by either TNF-alpha or high glucose Ang-1 increased survival (P < 0.05 for TNF- alpha; P < 0.01 for high glucose), whereas Ang-2 increased apoptosis. Ang-1 enhanced CD13 expression in a dose-dependent manner (P < 0.05) and stimulated pericyte migration in a synthetic matrix wound-healing assay that was associated with a change in F-actin organization. Addition of Tie-2 antisense confirmed that angiopoietins act through Tie-2.CONCLUSIONS. These findings demonstrate that Tie-2 is functional in pericytes and may play an important role in the progression of diabetic retinopathy, by regulating pericyte loss and influencing the activation state and recruitment of pericytes.