ABSTRACT
Myopia has been discussed as a risk factor for glaucoma. In this study, we characterized the relationship between ametropia and patterns of visual field (VF) loss in glaucoma. Reliable automated VFs (SITA Standard 24-2) of 120,019 eyes from 70,495 patients were selected from five academic institutions. The pattern deviation (PD) at each VF location was modeled by linear regression with ametropia (defined as spherical equivalent (SE) starting from extreme high myopia), mean deviation (MD), and their interaction (SE × MD) as regressors. Myopia was associated with decreased PD at the paracentral and temporal VF locations, whereas hyperopia was associated with decreased PD at the Bjerrum and nasal step locations. The severity of VF loss modulated the effect of ametropia: with decreasing MD and SE, paracentral/nasal step regions became more depressed and Bjerrum/temporal regions less depressed. Increasing degree of myopia was positively correlated with VF depression at four central points, and the correlation became stronger with increasing VF loss severity. With worsening VF loss, myopes have increased VF depressions at the paracentral and nasal step regions, while hyperopes have increased depressions at the Bjerrum and temporal locations. Clinicians should be aware of these effects of ametropia when interpreting VF loss.
ABSTRACT
Fibroblast growth factor (FGF) signaling is an essential regulator of lens epithelial cell proliferation and survival, as well as lens fiber cell differentiation. However, the identities of these FGF factors, their source tissue and the genes that regulate their synthesis are unknown. We have found that Chx10-Cre;Lhx2lox/lox mice, which selectively lack Lhx2 expression in neuroretina from E10.5, showed an early arrest in lens fiber development along with severe microphthalmia. These mutant animals showed reduced expression of multiple neuroretina-expressed FGFs and canonical FGF-regulated genes in neuroretina. When FGF expression was genetically restored in Lhx2-deficient neuroretina of Chx10-Cre;Lhx2lox/lox mice, we observed a partial but nonetheless substantial rescue of the defects in lens cell proliferation, survival and fiber differentiation. These data demonstrate that neuroretinal expression of Lhx2 and neuroretina-derived FGF factors are crucial for lens fiber development in vivo.
Subject(s)
Fibroblast Growth Factors/genetics , LIM-Homeodomain Proteins/physiology , Lens, Crystalline/embryology , Organogenesis/genetics , Retinal Neurons/physiology , Transcription Factors/physiology , Animals , Cell Differentiation/genetics , Embryo, Mammalian , Fibroblast Growth Factors/metabolism , Gene Expression Regulation, Developmental , LIM-Homeodomain Proteins/genetics , Lens, Crystalline/metabolism , Mice , Mice, Transgenic , Microphthalmos/embryology , Microphthalmos/genetics , Receptors, Fibroblast Growth Factor/genetics , Receptors, Fibroblast Growth Factor/metabolism , Retinal Neurons/metabolism , Signal Transduction/genetics , Transcription Factors/geneticsABSTRACT
Eye formation is regulated by a complex network of eye field transcription factors (EFTFs), including LIM-homeodomain gene LHX2. We disrupted LHX2 function at different stages during this process using a conditional knock-out strategy in mice. We find that LHX2 function is required in an ongoing fashion to maintain optic identity across multiple stages, from the formation of the optic vesicle to the differentiation of the neuroretina. At each stage, loss of Lhx2 led to upregulation of a set of molecular markers that are normally expressed in the thalamic eminence and in the anterodorsal hypothalamus in a portion of the optic vesicle or retina. Furthermore, the longer LHX2 function was maintained, the further optic morphogenesis progressed. Early loss of function caused profound mispatterning of the entire telencephalic-optic-hypothalamic field, such that the optic vesicle became mispositioned and appeared to arise from the diencephalic-telencephalic boundary. At subsequent stages, loss of Lhx2 did not affect optic vesicle position but caused arrest of optic cup formation. If Lhx2 was selectively disrupted in the neuroretina from E11.5, the neuroretina showed gross dysmorphology along with aberrant expression of markers specific to the thalamic eminence and anterodorsal hypothalamus. Our findings indicate a continual requirement for LHX2 throughout the early stages of optic development, not only to maintain optic identity by suppressing alternative fates but also to mediate multiple steps of optic morphogenesis. These findings provide new insight into the anophthalmic phenotype of the Lhx2 mutant and reveal novel roles for this transcription factor in eye development.
Subject(s)
Gene Expression Regulation, Developmental/genetics , LIM-Homeodomain Proteins/metabolism , Morphogenesis/genetics , Organogenesis/genetics , Transcription Factors/metabolism , Visual Pathways/physiology , Age Factors , Animals , Body Patterning/genetics , DNA-Binding Proteins/genetics , DNA-Binding Proteins/metabolism , Embryo, Mammalian , Eye Proteins/genetics , Eye Proteins/metabolism , Gene Expression Profiling , Gene Expression Regulation, Developmental/drug effects , Homeodomain Proteins/genetics , Homeodomain Proteins/metabolism , LIM-Homeodomain Proteins/genetics , Mice , Mice, Inbred C57BL , Mice, Transgenic , Mutation/genetics , Nerve Tissue Proteins/metabolism , Oligonucleotide Array Sequence Analysis , PAX6 Transcription Factor , Paired Box Transcription Factors/metabolism , Proteins/genetics , RNA, Untranslated , Repressor Proteins/metabolism , Retina/abnormalities , Retina/pathology , Tamoxifen/pharmacology , Transcription Factors/genetics , Visual Pathways/embryologyABSTRACT
PURPOSE: To evaluate the effect of lysosomal destabilization on NLRP3 inflammasome activation in RPE cells and to investigate the mechanisms by which inflammasome activation may contribute to the pathogenesis of age-related macular degeneration (AMD). METHODS: Human ocular tissue sections from patients with geographic atrophy or neovascular AMD were stained for NLRP3 and compared to tissues from age-matched controls. Expression of the IL-1ß precursor, pro-IL-1ß, was induced in ARPE-19 cells by IL-1α treatment. Immunoblotting was performed to assess expression of NLRP3 inflammasome components (NLRP3, ASC, and procaspase-1) and pro-IL-1ß in ARPE-19 cells. Lysosomes were destabilized using the lysosomotropic agent L-leucyl-L-leucine methyl ester (Leu-Leu-OMe). Active caspase-1 was detected using FAM-YVAD-FMK, a fluorescent-labeled inhibitor of caspases (FLICA) specific for caspase-1. IL-1ß was detected by immunoblotting and ELISA, and cytotoxicity was evaluated by LDH quantification. RESULTS: RPE of eyes affected by geographic atrophy or neovascular AMD exhibited NLRP3 staining at lesion sites. ARPE-19 cells were found to express NLRP3, ASC, and procaspase-1. IL-1α dose-dependently induced pro-IL-1ß expression in ARPE-19 cells. Lysosomal destabilization induced by Leu-Leu-OMe triggered caspase-1 activation, IL-1ß secretion, and ARPE-19 cell death. Blocking Leu-Leu-OMe-induced lysosomal disruption with the compound Gly-Phe-CHN(2) or inhibiting caspase-1 with Z-YVAD-FMK abrogated IL-1ß release and ARPE-19 cytotoxicity. CONCLUSIONS: NLRP3 upregulation occurs in the RPE during the pathogenesis of advanced AMD, in both geographic atrophy and neovascular AMD. Destabilization of RPE lysosomes induces NLRP3 inflammasome activation, which may contribute to AMD pathology through the release of the proinflammatory cytokine IL-1ß and through caspase-1-mediated cell death, known as "pyroptosis."