The effect of angiogenesis of the product of RPE specific pp344 gene

pP344基因被鉴定为鸡视网膜色素上皮（RPE）的标记物。预测的pP344蛋白与一类新型抑制tgf - β结合蛋白具有高度同源性。tgf - β超家族的成员具有血管生成的各种作用。本研究通过体外血管生成实验，测定pP344蛋白在猴视网膜中的表达和分布，探讨pP344蛋白对视网膜小管形成的影响。RT-PCR检测pP344基因对应mRNA的表达。采用免疫组化方法研究PP344蛋白在猴眼组织中的分布。研究了纯化pP344蛋白对人脐静脉内皮细胞小管形成的影响，并将其与人成纤维细胞在24孔板中共培养11天。第11天用CD31免疫染色法观察内皮小管的形成。通过计算机图像分析对内皮细胞源性小管进行定量分析。RT-PCR分析证实pP344基因在猴RPE中有表达。免疫组化分析显示PP344蛋白在猴RPE和脉络膜中的分布。pP344蛋白也广泛分布于猴视网膜。加入pP344融合蛋白后，内皮细胞衍生小管的长度呈浓度依赖性增加。在体外血管生成实验中，pP344融合蛋白促进小管形成。这些结果表明pPP344蛋白可能在眼部新生血管中起重要作用。

The pP344 gene was identified as a marker of chick retinal pigment epithelium(RPE). The predicted pP344 protein has high homology to a protein which represents a novel class of inhibitory TGF-beta binding protein. The member of TGF-beta superfamily has the various effects of angiogenesis. This study was undertaken to determine the expression and distribution of pP344 protein in the monkey retina, and investigate the effects of the pP344 protein on tubule formation in in vitro angiogenesis assay. The expression of mRNA corresponding to pP344 gene was examined by RT-PCR. The distribution of PP344 protein in monkey eye was investigated by immunohistochemical study. The effects of purified pP344 protein on tubule formation were studied in human umbilical vein endothelial cells, which were co-cultured with human fibroblasts in a 24-well plate over a period of 11 days. Endothelial tubulogenesis was visualized by immunostaining for CD31 on day 11. Endothelial cell-derived tubules were quantified by computer image analysis. RT-PCR analysis demonstrated the expression of pP344 gene in monkey RPE. By immunohistochemical analysis, the distribution of the PP344 protein was shown in the monkey RPE and choroid. The pP344 protein was also widely distributed in the monkey retina. With the addition of pP344 fusion protein, the length of endothelial cell derived tubules was increased in a concentration-dependent manner. The pP344 fusion protein promotes tubule formation in in vitro angiogenesis assay. These results indicated pPP344 protein may have a significant role in ocular neovascularization.