Abstract
Abstract: :
Purpose: 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–ß binding protein. The member of TGF–ß 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. Methods: The expression of pP344 mRNA 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. Results: 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 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. Conclusions: PP344 protein promoted tubule formation in in vitro angiogenesis assay. These results indicated that PP344 protein may have a significant role in ocular neovascularization.
Keywords: retinal pigment epithelium • immunohistochemistry • growth factors/growth factor receptors