Abstract
Abstract: :
Purpose:The present study focuses on the role of CD81 (TAPA, the target of the antiproliferative antibody) and other members of the tetraspanin family in the cellular proliferation that occurs following retinal injury. Tetraspanins and specifically CD81 in association with adhesion molecules regulate, cell proliferation, cell migration and stable cell contacts. In association with membrane proteins in lymphocytes, this family of proteins can regulate inflammatory and immune responses following injury. Methods:The retina of adult Sprague-Dawley rats were injured by scraping the retina with a needle. A time course of protein levels after injury was examined comparing the normal retina to injured retina: 1, 2, 3, 6, 13 and 30 days following injury. The level and distribution of proteins was defined by immunoblot and immunohistochemical methods. An Affymetrics microarray analysis and real time PCR defined the level of specific mRNAs. Results:We observed that CD81 was found in all layers of the normal retina and that it was upregulated following injury. The microarray analysis revealed a 1.8 fold increase in the CD81 mRNA. In addition we found other members of the tetraspanin family in the retina: CD82, CD37, CD9, CD63 and RDS peripherin. Most of the tetraspanins were upregulated 7 days after a retinal injury. We are currently analyzing the cellular localization of CD81 with a specific emphasis on retinal pigment epithelium (RPE). Currently, we know that CD81 is expressed by Muller cells and RPE. CD81 is upregulated in both of these cell types following injury. Conclusion:CD81 as well as other members of the tetraspanin family are found in the normal rat retina. Previous work demonstrates that CD81 was expressed in retinal glia (Müller cells, astrocytes and RPE) and that it is part of the molecular complex controlling glial cell proliferation. The present study demonstrated that CD81 as well as other tetraspanins are upregulated following injury. We are in the process of defining the role the tetraspanins in regulating cell proliferation following retinal injury.
Keywords: 561 retinal degenerations: cell biology • 631 wound healing • 316 animal model