Mitochondrial pathogenic mechanism and degradation in optineurin E50K mutation-mediated retinal ganglion cell degeneration.

Mutations in optineurin (OPTN) are linked to the pathology of primary open angle glaucoma (POAG) and amyotrophic lateral sclerosis. Emerging evidence indicates that OPTN mutation is involved in accumulation of damaged mitochondria and defective mitophagy. Nevertheless, the role played by an OPTN E50K mutation in the pathogenic mitochondrial mechanism that underlies retinal ganglion cell (RGC) degeneration in POAG remains unknown.

Optineurin: The autophagy connection.

Optineurin is a cytosolic protein encoded by the OPTN gene. Mutations of OPTN are associated with normal tension glaucoma and amyotrophic lateral sclerosis. Autophagy is an intracellular degradation system that delivers cytoplasmic components to the lysosomes.

Angiogenesis in glaucoma filtration surgery and neovascular glaucoma: A review.

Angiogenesis may pose a clinical challenge in glaucoma, for example, during the wound healing phase after glaucoma filtration surgery and in the severe secondary glaucoma called neovascular glaucoma (NVG). Upregulation of vascular endothelial growth factor (VEGF), a key mediator of angiogenesis, occurs in eyes that have undergone glaucoma filtration surgery, as well as those with NVG. This has led investigation of the ability of anti-vascular endothelial growth factor therapy to improve outcomes, and we examine the findings with respect to the safety and efficacy of anti-vascular endothelial growth factor agents, mainly bevacizumab and ranibizumab, in eyes that have undergone glaucoma filtration surgery or have NVG.

Induction of autophagy in rats upon overexpression of wild-type and mutant optineurin gene.

Background: Optineurin is a gene associated with normal tension glaucoma and amyotrophic lateral sclerosis. It has been reported previously that in cultured RGC5 cells, the turnover of endogenous optineurin involves mainly the ubiquitin-proteasome pathway (UPP). When optineurin is upregulated or mutated, the UPP function is compromised as evidenced by a decreased proteasome β5 subunit (PSMB5) level and autophagy is induced for clearance of the optineurin protein.

ABCB1 transporter and Toll-like receptor 4 in trabecular meshwork cells.

Purpose: The aqueous humor nourishes the avascular tissues of the anterior segment, and the trabecular meshwork (TM) plays a role in the efflux of endogenous substances and xenobiotics from the aqueous humor. ATP (ATP)-binding cassette (ABC) transporter superfamily members respond to stressors such as hypoxia, cytokine signaling, and aging. The innate immune system within the TM, particularly Toll-like receptor 4 (TLR4) and its ligands, e.

Cellular processing of myocilin.

Background: Myocilin (MYOC) is a gene linked directly to juvenile- and adult-onset open angle glaucoma. Mutations including Pro370Leu (P370L) and Gln368stop (Q368X) have been identified in patients. In the present study, we investigated the processing of myocilin in human trabecular meshwork (TM) cells as well as in inducible, stable RGC5 cell lines.

Differential expression of genes in cells cultured from juxtacanalicular trabecular meshwork and Schlemm's canal.

Purpose: The purpose of this study was to distinguish differences in gene expression between cells cultured from the juxtacanalicular trabecular meshwork (JCTM) and those from Schlemm's canal (SC), to gain clues to differences between those cell types, and to add to our baseline knowledge of gene expression differences in these cell types for later comparison between cells from nonprimary open-angle glaucoma (POAG) and POAG outflow tissues.

Methods: A set of JCTM and SC cells was cultured from each of 2 donor eyes by an explant method, grown to passage 3, and frozen in liquid nitrogen. The cells were thawed, total RNA was extracted, and the probes made from total RNAs were hybridized to MICROMAX human cDNA microarray slides in 2 separate trials.

sCD44 overexpression increases intraocular pressure and aqueous outflow resistance.

Purpose: CD44 plays major roles in multiple physiologic processes. The ectodomain concentration of the CD44 receptor, soluble CD44 (sCD44), is significantly increased in the aqueous humor of primary open-angle glaucoma (POAG). The purpose of this study was to determine if adenoviral constructs of CD44 and isolated 32-kDa sCD44 change intraocular pressure (IOP) in vivo and aqueous outflow resistance in vitro.

Sustained release of matrix metalloproteinase-3 to trabecular meshwork cells using biodegradable PLGA microparticles.

Accumulation of extracellular matrix (ECM) materials in the trabecular meshwork (TM) is believed to be a contributing factor to intraocular pressure (IOP) elevation, a risk factor/cause of primary open angle glaucoma, a major blinding disease. Matrix metalloproteinase-3 (MMP-3) is one of the proteinases that can effectively degrade ECM elements such as fibronectin, and MMP-3 delivery to the TM represents a promising approach for IOP reduction and treatment of glaucoma. In this study, we tested the feasibility of using polymeric microparticles to achieve a slow and sustained release of active MMP-3 to cultured human TM cells.

Establishment of inducible wild type and mutant myocilin-GFP-expressing RGC5 cell lines.

Background: Myocilin is a gene linked directly to juvenile- and adult-onset open angle glaucoma. Mutations including Gln368stop (Q368X) and Pro370Leu (P370L) have been identified in patients. The exact role of myocilin and its functional association with glaucoma are still unclear.

Wnt activation by wild type and mutant myocilin in cultured human trabecular meshwork cells.

Background: Myocilin is a gene linked to the most prevalent form of glaucoma, a major blinding disease. The trabecular meshwork (TM), a specialized eye tissue, is believed to be involved, at least in part, in the development of glaucoma. The Pro³⁷⁰ to Leu (P370L) mutation of myocilin is associated with severe glaucoma phenotypes and Gln³⁶⁸ stop (Q368X) is the most common myocilin mutation reported.

Cellular and molecular biology of optineurin.

Optineurin is a gene linked to glaucoma, amyotrophic lateral sclerosis, other neurodegenerative diseases, and Paget's disease of bone. This review describes the characteristics of optineurin and summarizes the cellular and molecular biology investigations conducted so far on optineurin. Data from a number of laboratories indicate that optineurin is a cytosolic protein containing 577 amino acid residues.

Decellularized human cornea for reconstructing the corneal epithelium and anterior stroma.

In this project, we strived to develop a decellularized human cornea to use as a scaffold for reconstructing the corneal epithelium and anterior stroma. Human cadaver corneas were decellularized by five different methods, including detergent- and nondetergent-based approaches. The success of each method on the removal of cells from the cornea was investigated.

Novel mutation and three other sequence variants segregating with phenotype at keratoconus 13q32 susceptibility locus.

Keratoconus (KTCN), a non-inflammatory corneal disorder characterized by stromal thinning, represents a major cause of corneal transplantations. Genetic and environmental factors have a role in the etiology of this complex disease. Previously reported linkage analysis revealed that chromosomal region 13q32 is likely to contain causative gene(s) for familial KTCN.

Myocilin and Optineurin: Differential Characteristics and Functional Consequences.

Myocilin and optineurin are two genes linked to glaucoma, a major blinding disease characterized by progressive loss of retinal ganglion cells and their axons. This review describes the characteristics of myocilin and optineurin protein products and summarizes the consequences of ectopically expressed wild type and mutant myocilin and optineurin in trabecular meshwork and/or neuronal cells. Myocilin and optineurin exhibit differential characteristics and have divergent functional consequences.

Processing of optineurin in neuronal cells.

Optineurin is a gene linked to amyotrophic lateral sclerosis, Paget disease of bone, and glaucoma, a major blinding disease. Mutations such as E50K were identified in glaucoma patients. We investigated herein the involvement of ubiquitin-proteasome pathway (UPP) and autophagy, two major routes for protein clearance, in processing of optineurin in a retinal ganglion cell model line RGC5 and neuronal PC12 cells.

Suppression of transforming growth factor-β effects in rabbit subconjunctival fibroblasts by activin receptor-like kinase 5 inhibitor.

Purpose: Transforming growth factor-β (TGF-β) activity has been implicated in subconjunctival scarring in eyes following glaucoma filtration surgery (GFS). The purpose of this study is to determine whether an inhibitor for activin receptor-like kinase (ALK) 5 (also known as TGF-β receptor type I) could suppress TGF-β activity and thereby promote filtering bleb survival after GFS in a rabbit model.

Methods: An ALK-5 inhibitor, SB-505124, was used.

The role of crumbs genes in the vertebrate cornea.

Purpose: To evaluate the role of crumbs genes and related epithelial polarity loci in the vertebrate cornea.

Methods: The authors used histologic analysis and electron microscopy to evaluate the corneas of zebrafish mutant for a crumbs locus oko meduzy (ome) and in mutants of four other loci, nagie oko (nok), heart and soul (has), mosaic eyes (moe), and ncad (formerly glass onion), that function in the same or related genetic pathways. In parallel, they performed an evaluation of corneas in human carriers of a crumbs gene, CRB1, and mutations using topography and biomicroscopy.

Impairment of protein trafficking upon overexpression and mutation of optineurin.

Background: Glaucoma is a major blinding disease characterized by progressive loss of retinal ganglion cells (RGCs) and axons. Optineurin is one of the candidate genes identified so far. A mutation of Glu(50) to Lys (E50K) has been reported to be associated with a more progressive and severe disease.

Posttranslational modifications, localization, and protein interactions of optineurin, the product of a glaucoma gene.

Background: Glaucoma is a major blinding disease. The most common form of this disease, primary open angle glaucoma (POAG), is genetically heterogeneous. One of the candidate genes, optineurin, is linked principally to normal tension glaucoma, a subtype of POAG.

Wnt gene expression in human trabecular meshwork cells.

Purpose: The aim of this study was to examine the expression of genes related to the Wnt signaling pathway, such as beta-catenin (CTNNB1) and secreted frizzled-related protein-1 (sFRP1), in human trabecular meshwork (TM) cells. In addition, the effect of oxidative stress on Wnt signaling was evaluated.

Methods: All experiments were conducted using second- or third-passaged human TM cells.

In vitro antiviral activity of neem (Azardirachta indica L.) bark extract against herpes simplex virus type-1 infection.

Herpes simplex virus type 1 (HSV-1) causes significant health problems from periodical skin and corneal lesions to encephalitis. We report here that an aqueous extract preparation from the barks of neem plant Azardirachta indica acts as a potent entry inhibitor against HSV-1 infection into natural target cells. The neem bark extract (NBE) significantly blocked HSV-1 entry into cells at concentrations ranging from 50 to 100 microg/ml.

Differential effects of myocilin and optineurin, two glaucoma genes, on neurite outgrowth.

Myocilin and optineurin are two genes linked to glaucoma, a major blinding disease characterized by progressive loss of retinal ganglion cells (RGCs) and their axons. To investigate the effects of force-expressed wild-type and mutant myocilin and optineurin on neurite outgrowth in neuronal cells, we transiently transfected cells with pEGFP-N1 (mock control) as well as myocilin and optineurin plasmids including pMYOC(WT)-EGFP, pMYOC(P370L)-EGFP, pMYOC(1-367)-EGFP, pOPTN(WT)-EGFP, and pOPTN(E50K)-EGFP. PC12 cells transfected with pEGFP-N1 produced, as anticipated, long and extensive neuritis on nerve growth factor induction.

Effects of Sp1 overexpression on cultured human corneal stromal cells.

Sp1, a transcription factor, is upregulated in keratoconus, a cornea-thinning disease. Keratoconus corneas have also been shown to contain increased levels of degradative enzymes such as cathepsin B and decreased proteinase inhibitors such as alpha1-proteinase inhibitor (alpha1-PI). We transfected cultured human corneal stromal cells to overexpress Sp1.