The long-range goal of this proposal is to understand the role that tight junctions play in regulating the outer blood-retinal barrier. Malfunction of the blood-retinal barrier is implicated in many retinopathies. This proposal examines how immature, leaky, tight junctions are converted into an effective barrier, and how this process is regulated by the neural retina. During development, rudimentary tight junctions of the retinal pigment epithelium (RPE) undergo this conversion to form the outer blood-retinal barrier. This laboratory devised an innovative culture model that revealed different stages in the assembly of a continuous network of tight junctions followed by its conversion to a low permeability form. The current proposal focuses on the ability of retinal conditioned medium to reorganize patches of tight junctions into a continuous network, and on the differences in the permeability of tight junctional strands that are obtained in older versus younger embryonic RPE. Differential screening of high density microarrays and more traditional molecular techniques will be used to address two hypotheses: 1) Retinal factors regulate the formation and assembly of junctional strands into a functional network by regulating the expression of tight junctional proteins and the effectors of tight junctional proteins. 2) The permeability properties of individual junctional strands assembled under retinal stimulation depends upon the embryonic age of the RPE because of the differential expression of interchangeable tight junction components. Although studies reported in the literature suggest candidate proteins to fill these roles, the unbiased genomic screen proposed here is expected to reveal novel tight junctional proteins and regulatory pathways. The regulation of the tight junction has proved to be enigmatic. Recent advances in the development of reagents coupled with this novel culture model will advance our understanding of this essential structure of the outer blood-retinal barrier. ? ?

Agency
National Institute of Health (NIH)
Institute
National Eye Institute (NEI)
Type
Research Project (R01)
Project #
5R01EY008694-13
Application #
7025619
Study Section
Special Emphasis Panel (ZRG1-VISC (01))
Program Officer
Mariani, Andrew P
Project Start
1993-07-01
Project End
2008-02-28
Budget Start
2006-03-01
Budget End
2008-02-28
Support Year
13
Fiscal Year
2006
Total Cost
$319,316
Indirect Cost
Name
Yale University
Department
Surgery
Type
Schools of Medicine
DUNS #
043207562
City
New Haven
State
CT
Country
United States
Zip Code
06520
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Cong, Lidan; Sun, Dawei; Zhang, Zhongyu et al. (2008) A novel rabbit model for studying RPE transplantation. Invest Ophthalmol Vis Sci 49:4115-25
Rizzolo, Lawrence J (2007) Development and role of tight junctions in the retinal pigment epithelium. Int Rev Cytol 258:195-234
Rizzolo, Lawrence J; Chen, Xiang; Weitzman, Matthew et al. (2007) Analysis of the RPE transcriptome reveals dynamic changes during the development of the outer blood-retinal barrier. Mol Vis 13:1259-73
Luo, Yan; Fukuhara, Masayuki; Weitzman, Matthew et al. (2006) Expression of JAM-A, AF-6, PAR-3 and PAR-6 during the assembly and remodeling of RPE tight junctions. Brain Res 1110:55-63
Luo, Yan; Zhuo, Yehong; Fukuhara, Masayuki et al. (2006) Effects of culture conditions on heterogeneity and the apical junctional complex of the ARPE-19 cell line. Invest Ophthalmol Vis Sci 47:3644-55
Rahner, Christoph; Fukuhara, Masayuki; Peng, Shaomin et al. (2004) The apical and basal environments of the retinal pigment epithelium regulate the maturation of tight junctions during development. J Cell Sci 117:3307-18
Peng, Shaomin; Rahner, Christoph; Rizzolo, Lawrence J (2003) Apical and basal regulation of the permeability of the retinal pigment epithelium. Invest Ophthalmol Vis Sci 44:808-17
Kojima, S; Rahner, C; Peng, S et al. (2002) Claudin 5 is transiently expressed during the development of the retinal pigment epithelium. J Membr Biol 186:81-8
Bumsted, K M; Rizzolo, L J; Barnstable, C J (2001) Defects in the MITF(mi/mi) apical surface are associated with a failure of outer segment elongation. Exp Eye Res 73:383-92

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