Abstract
Purpose: :
Methyl-CpG-binding protein 2 (MeCP2) is an orchestrator of epithelial myofibroblast transdifferentiation and a pivotal regulator in the development of fibrotic response. MeCP2, especially phosphorylatd MeCP2 421, plays an important role in the pathogenesis of neovascularization and the response to stress and inflammation. The current research sought to investigate the expression of phosphorylated MeCP2 in human proliferative diabetic retinopathy (PDR) membranes and its association with VEGF and PEDF expression.
Methods: :
Five surgically excised membranes from patients (ages 45-70; 3 male, 2 female) with PDR were prepared for immunostaining. Tissues were snap frozen and sectioned at 6 µm. Thawed tissue sections were air dried, rehydrated with PBS (pH 7.4), fixed in acetone, and blocked with 5% normal goat serum. Sections were stained with anti-MeCP2 phosphorylated forms (80 and 421), and anti-VEGF, anti-PEDF and anti-DNA methyltransferase3a (DNMT3a). The red chromagen color was developed using amino ethyl carbazole . The co-localization of MeCP2 and VEGF or PEDF in the membranes was visualized using FITC and rhodamine-labeled secondary antibodies. Slides were examined using a Zeiss LSM510 confocal microscope.
Results: :
Both phosphorylated MeCP2 80 and 421 were positively stained in the PDR membranes; however, the expression of MeCP2 421 was much stronger than that of MeCP2 80. The high MeCP2 421 expression was associated with strong expression of VEGF and negatively correlated with expression of PEDF in the membranes. The immunoreactivity of DNMT was also abundant in the PDR sections.
Conclusions: :
The expression of phosphorylated MeCP2 421 is increased in the membranes of PDR. The upregulated expression of MeCP2 421 may be related to the high expression of VEGF in the membranes.
Keywords: diabetic retinopathy • pathology: human • neovascularization