Jiang Aihua, Hu Wenzheng, Meng Hongdi, Gao Hua, Qiao Xiaoxi
Department of Ophthalmology, Indiana University School of Medicine, Indianapolis, Indiana 46202, USA.
Invest Ophthalmol Vis Sci. 2009 Feb;50(2):844-50. doi: 10.1167/iovs.08-2447. Epub 2008 Oct 20.
The very low-density lipoprotein receptor (VLDLR) knockout (vldlr(-/-)) mouse has been identified as a model for retinal angiomatous proliferation with subretinal neovascularization (SNV) evolving from retinal vessels. The effects of VLDLR on the angiogenic functions of retinal vascular endothelial cells (RVECs) in vivo and in vitro were examined.
Immunofluorescent staining of markers for activated endothelial cells was performed with CD105 and CD106 antibodies. Proliferation, tube formation, and migration assays were carried out in RVECs isolated from wild-type and vldlr(-/-) mice to assess the angiogenic functions in vitro. The effect of VLDLR blockage on wild-type RVEC proliferation was also examined.
The expression of CD105 and CD106 was significantly upregulated in the retinas of adult vldlr(-/-) mice, especially at lesion sites. An intense CD105 signal was found in the inner retinas of vldlr(-/-) mice starting at postnatal day 14, before the onset of SNV. In vitro proliferation assays revealed a significantly enhanced (approximately 20%-100%) growth rate in vldlr(-/-) RVECs compared with that in the wild-type RVECs. The formation of capillary-like structures in vldlr(-/-) RVECs was approximately 3 to 11 times greater than in wild-type RVECs. Migration of vldlr(-/-) RVECs was 1.3 to 3.7 times that of wild-type. VLDLR blockage using a receptor-associated protein or neutralizing anti-VLDLR antibodies significantly enhanced the proliferation rate in wild-type RVECs by more than 200% and 30%, respectively.
VLDLR is a potent endogenous inhibitor that negatively regulates the angiogenic properties of RVECs. Loss of VLDLR activates RVECs and significantly enhances angiogenesis in vivo and in vitro.
极低密度脂蛋白受体（VLDLR）基因敲除（vldlr(-/-)）小鼠已被确定为视网膜血管瘤样增殖伴视网膜下新生血管形成（SNV）从视网膜血管演变而来的模型。研究了VLDLR对体内外视网膜血管内皮细胞（RVECs）血管生成功能的影响。
用CD105和CD106抗体对活化内皮细胞标志物进行免疫荧光染色。对从野生型和vldlr(-/-)小鼠分离的RVECs进行增殖、管形成和迁移试验，以评估体外血管生成功能。还研究了VLDLR阻断对野生型RVEC增殖的影响。
CD105和CD106在成年vldlr(-/-)小鼠视网膜中的表达显著上调，尤其是在病变部位。在出生后第14天，在SNV开始之前，在vldlr(-/-)小鼠的视网膜内层发现了强烈的CD105信号。体外增殖试验显示，与野生型RVECs相比，vldlr(-/-) RVECs的生长速率显著提高（约20%-100%）。vldlr(-/-) RVECs中毛细血管样结构的形成比野生型RVECs大约多3至11倍。vldlr(-/-) RVECs的迁移是野生型的1.3至3.7倍。使用受体相关蛋白或中和抗VLDLR抗体阻断VLDLR分别使野生型RVECs的增殖率显著提高200%以上和30%。
VLDLR是一种有效的内源性抑制剂，对RVECs的血管生成特性起负调节作用。VLDLR的缺失激活了RVECs，并在体内外显著增强了血管生成。
