Biomedical subjects

Jean-Jacques De Laey

Publications and source records attributed to Jean-Jacques De Laey.

4 recordsLinked to original sources

PubMed2004

Mutations of VMD2 splicing regulators cause nanophthalmos and autosomal dominant vitreoretinochoroidopathy (ADVIRC).

PURPOSE: To investigate the genetic basis of autosomal dominant vitreoretinochoroidopathy (ADVIRC), a rare, inherited retinal dystrophy that may be associated with defects of ocular development, including nanophthalmos. METHODS: A combination of linkage analysis and DNA sequencing in five families was used to identify disease-causing mutations in VMD2. The effect of these mutations on splicing was assessed using a minigene system. RESULTS: Three pathogenic sequence alterations in VMD2 were identified in five families with nanophthalmos associated with ADVIRC. All sequences showed simultaneous missense substitutions and exon skipping. CONCLUSIONS: VMD2 encodes bestrophin, a transmembrane protein located at the basolateral membrane of the RPE, that is also mutated in Best macular dystrophy. We support that each heterozygous affected individual produces three bestrophin isoforms consisting of the wild type and two abnormal forms: one containing a missense substitution and the other an in-frame deletion. The data showed that VMD2 mutations caused defects of ocular patterning, supporting the hypothesized role for the RPE, and specifically VMD2, in the normal growth and development of the eye.

Bestrophins↗

PubMed2004

[Geriatric eye diseases].

Ageing of the eye affects all ocular structures. Presbyopia is an early manifestation of physiological ageing resulting in the impossibility to read without additional spectacle correction. Some systemic disorders may interfere with the physiological ageing of the eye and cause blindness. In the western countries blindness is caused by age-related macular degeneration (26%), glaucoma (20.5%), cataract (11.2%), diabetic retinopathy (8.9%) and ischemic optic neuropathy (4 %).

Aged↗

PubMed2003

Invasion of retinal pigment epithelial cells: N-cadherin, hepatocyte growth factor, and focal adhesion kinase.

PURPOSE: To investigate the role of N-cadherin and hepatocyte growth factor (HGF) in the invasion of collagen type I by human retinal pigment epithelial (RPE) cells. METHODS: RPE sheets from eight human eyes were used for characterization through Western blot analysis of the expression of cadherin in total lysates or after immunoprecipitation with anti beta-catenin antibody. First-passage primary cultures of RPE sheets were successfully established from 28 of 56 human eyes. First-passage primary RPE cell cultures on glass substrate, consisting of patches of cells, were used for immunocytochemistry. Fifteen first-passage primary RPE cell cultures in culture vessels were grown to confluence. Four of the 15 first-passage primary RPE cell cultures were investigated for cadherin expression by immunocytochemistry, and the other 11 were further subcultured for two to six passages. These 11 cultures were used for functional assays and investigated for expression of cadherin at regular time intervals. Cells from passage-3 to -4 primary RPE cell cultures were tested for invasion into collagen type I gels, with or without neutralizing antibodies for HGF and N-cadherin, respectively. Activation of the c-Met receptor for HGF and of focal adhesion kinase (FAK) was investigated by immunoprecipitation with anti-phosphotyrosine antibody, gel electrophoresis, and immunostaining on Western blot. Levels of HGF in conditioned medium (CM) of RPE cells were determined by ELISA. RESULTS: RPE cells in culture displayed two phenotypes: Both fibroblast-like and epithelioid cells were present in all 15 first-passage primary cultures and in further passaged cultures derived therefrom. When seeded on collagen, all RPE cells acquired a fibroblast-like phenotype and invaded the collagen type I gel. RPE cells also stimulated branching morphogenesis of MDCK/AZ epithelial canine kidney cell colonies inside collagen. HGF was found in RPE CM, suggesting an autocrine loop for invasion through its c-Met receptor. HGF-neutralizing antibody inhibited invasion of collagen. The major cadherin expressed by RPE cells in culture was N(euronal)-cadherin. Invasion of collagen by RPE cells was also inhibited by an N-cadherin-neutralizing antibody. N-cadherin and c-Met coimmunoprecipitated in RPE cells. FAK and c-Met were both phosphorylated in RPE cells in culture, and phosphorylation was inhibited by antibodies neutralizing either N-cadherin or HGF. CONCLUSIONS: The present investigation provides evidence for an autocrine HGF/c-Met loop that stimulates RPE cell invasion into collagen through FAK. The invasion-stimulatory molecule N-cadherin also activates FAK in invasive RPE cells.

Animals↗

PubMed2002

Structure and function of the N-cadherin/catenin complex in retinoblastoma.

PURPOSE: To identify in human retinoblastoma and normal retinal tissue the type of cadherin, its relationship with cytoplasmic catenins, and its participation in invasion. METHODS: The cadherin/catenin complex was characterized in surgical retinoblastoma specimens from five patients and human retinas from four donor eyes by immunocytochemistry, flow cytometry, and coimmunoprecipitation with antibodies against N-cadherin, alpha-catenin, and beta-catenin, followed by Western blot analysis or autoradiography. Y79 and WERI-Rb-1 retinoblastoma cell lines serve the evaluation of the cadherin/catenin complex in aggregation and collagen type I invasion in vitro. The association of the cadherin/catenin complex with the cytoskeleton was examined by an antibody-capping assay. RESULTS: In retinoblastoma and normal retina N-cadherin associated with alpha-catenin and beta-catenin but not E- or P-cadherin. The N-cadherin/catenin complex formed a regular, linear, and continuous honeycomb pattern in normal retina that was irregular, clustered, and interrupted in retinoblastoma. The N-cadherin/catenin complex was found also in the retinoblastoma cell lines WERI-Rb and Y79, in which it also showed an irregular pattern. Both cell lines were invasive in collagen type I, and invasion was inhibited by the GC-4 antibody, which functionally neutralizes N-cadherin. Less GC-4 antibody was needed to inhibit invasion of Y79 cells, which expressed N-cadherin at a lower level, than to inhibit invasion of WERI-Rb-1 cells. In both cell lines, antibody capping of the N-cadherin/catenin complex indicated that its linkage with the cytoskeleton were weak or absent. CONCLUSIONS: Retinoblastoma cells, in contrast with normal retina, express an N-cadherin/catenin complex that is irregularly distributed and weakly linked to the cytoskeleton. In retinoblastoma, this complex acts as an invasion promoter.

Autoradiography↗