Differential Lysyl oxidase like 1 expression in pseudoexfoliation glaucoma is orchestrated via DNA methylation.

Pseudoexfoliation syndrome (PXF) is the most common cause of secondary open angle glaucoma worldwide. Single nucleotide polymorphisms (SNPs) in the gene Lysyl oxidase like 1 (LOXL1) are strongly associated with the development of pseudoexfoliation glaucoma (PXFG). However, these SNPs are also present in 50-80% of the general population, suggestive of other factors being involved in the pathogenesis of PXFG.

The role of lamina cribrosa tissue stiffness and fibrosis as fundamental biomechanical drivers of pathological glaucoma cupping.

The primary biomechanical driver of pathological glaucomatous cupping remains unknown. Finite element modeling indicates that stress and strain play key roles. In this article, primarily a review, we utilize known biomechanical data and currently unpublished results from our lab to propose a three-stage, tissue stiffness-based model to explain glaucomatous cupping occurring at variable levels of translaminar pressure (TLP).

Lysyl Oxidase Like 1: Biological roles and regulation.

Lysyl Oxidase Like 1 (LOXL1) is a gene that encodes for the LOXL1 enzyme. This enzyme is required for elastin biogenesis and collagen cross-linking, polymerising tropoelastin monomers into elastin polymers. Its main role is in elastin homeostasis and matrix remodelling during injury, fibrosis and cancer development.

Increased Substrate Stiffness Elicits a Myofibroblastic Phenotype in Human Lamina Cribrosa Cells.

Purpose: Alteration in the extracellular matrix (ECM) of the optic nerve head (ONH) causes lamina cribrosa (LC) fibrosis and affects the mechanical integrity of the ONH. Increased ECM tissue stiffness drives myofibroblast activation leading to tissue fibrosis throughout the body. Here using primary human LC cells, we investigate the effect of substrate stiffness on profibrotic changes, which might be a key molecular mechanism driving ECM remodeling of the LC in primary open-angle glaucoma (POAG) glaucoma.

Increased Global DNA Methylation and Decreased TGFβ1 Promoter Methylation in Glaucomatous Lamina Cribrosa Cells.

Background: Glaucoma is an optic neuropathy that affects 60 million people worldwide. There is an underlying fibrosis associated with the lamina cribrosa (LC) in glaucoma. DNA methylation is well established in regulating fibrosis and may be a therapeutic target for glaucoma.

Hypoxia-Induced Changes in DNA Methylation Alter RASAL1 and TGFβ1 Expression in Human Trabecular Meshwork Cells.

Purpose: Fibrosis and a hypoxic environment are associated with the trabecular meshwork (TM) region in the blinding disease glaucoma. Hypoxia has been shown to alter DNA methylation, an epigenetic mechanism involved in regulating gene expression such as the pro-fibrotic transforming growth factor (TGF) β1 and the anti-fibrotic Ras protein activator like 1 (RASAL1). The purpose of this study was to compare DNA methylation levels, and the expression of TGFβ1 and RASAL1 in primary human normal (NTM) with glaucomatous (GTM) cells and in NTM cells under hypoxic conditions.

The role of lamina cribrosa cells in optic nerve head fibrosis in glaucoma.

Glaucoma is a chronic progressive optic neuropathy. There are extracellular matrix (ECM) changes associated with optic disc cupping in the optic nerve head (ONH) and subsequent visual field defects. The primary risk factor for onset and progression of glaucoma is raised intraocular pressure (IOP).

The Function of Matricellular Proteins in the Lamina Cribrosa and Trabecular Meshwork in Glaucoma.

Purpose: To review the current literature regarding the role of matricellular proteins in glaucoma, specifically in the lamina cribrosa (LC) region of the optic nerve head (ONH) and the trabecular meshwork (TM).

Methods: A literature search was performed for published articles describing the expression and function of matricellular proteins such as thrombospondin (TSP), connective tissue growth factor (CTGF), secreted protein acidic and rich in cysteine (SPARC), and periostin in glaucoma.

Results: In glaucoma, there are characteristic extracellular matrix (ECM) changes associated with optic disc cupping in the ONH and subsequent visual field defects.

Lipofuscin accumulation and autophagy in glaucomatous human lamina cribrosa cells.

Background: Disease associated alterations in the phenotype of lamina cribrosa (LC) cells are implicated in changes occurring at the optic nerve head (ONH) in glaucoma. Lipofuscin, the formation of which is driven by reactive oxygen species (ROS), is an intralysosomal, non-degradable, auto-fluorescent macromolecule which accumulates with age and can affect autophagy - the lysosomal degradation of a cell's constituents. We aimed to compare the content of lipofuscin-like material and markers of autophagy in LC cells from normal and glaucoma donor eyes.

The role of matricellular proteins in glaucoma.

Glaucoma is an optic neuropathy affecting approximately 60million people worldwide and is the second most common cause of irreversible blindness. Elevated intraocular pressure (IOP) is the main risk factor for developing glaucoma and is caused by impaired aqueous humor drainage through the trabecular meshwork (TM) and Schlemm's canal (SC). In primary open angle glaucoma (POAG), this elevation in IOP in turn leads to deformation at the optic nerve head (ONH) specifically at the lamina cribrosa (LC) region where there is also a deposition of extracellular matrix (ECM) molecules such as collagen and fibronectin.

Elevated maxi-K(+) ion channel current in glaucomatous lamina cribrosa cells.

The connective tissue plates of the lamina cribrosa (LC) region are continuously exposed to a mechanically dynamic environment. To study how the LC cells respond to these mechanical forces, we measured the mechano-sensitive calcium dependent maxi-K(+) ion channel current in the cell membrane of LC cells of glaucoma and normal subjects. Primary culture LC cells from 7 normal and 7 age matched glaucoma donors were studied.

Preparation of pre-confluent retinal cells increases graft viability in vitro and in vivo: a mouse model.

Purpose: Graft failure remains an obstacle to experimental subretinal cell transplantation. A key step is preparing a viable graft, as high levels of necrosis and apoptosis increase the risk of graft failure. Retinal grafts are commonly harvested from cell cultures.

Protein macroarray profiling of serum autoantibodies in pseudoexfoliation glaucoma.

Purpose: Complex repertoires of IgG autoantibodies have been detected against ocular antigens in patients with glaucoma. The goal was to identify and characterize the IgG autoantibody repertoires in sera of patients with pseudoexfoliation glaucoma (PXFG) with protein macroarrays.

Methods: Serum samples of 21 patients with PXFG and 19 age- and sex-matched control subjects were profiled on high-density colony protein macroarrays expressing His-tagged recombinant human proteins derived from a human fetal brain cDNA library.

Rosiglitazone acts as a neuroprotectant in retinal cells via up-regulation of sestrin-1 and SOD-2.

Rosiglitazone is a member of the thiazolidinedione family of synthetic peroxisome proliferator-activated receptor (PPAR) agonists. It is a selective ligand of the PPARgamma subtype and functions by regulating the transcription of insulin-responsive genes. A screen of FDA-approved compounds identified rosiglitazone as a novel anti-apoptotic agent in retinal cells both in vitro and in vivo, functioning as a neuroprotectant in response to oxidative and calcium stress.

Histone deacetylase activity in conjunction with E2F-1 and p53 regulates Apaf-1 expression in 661W cells and the retina.

Apaf-1 and the cysteine proteases known as caspases are genes central to the intrinsic apoptotic pathway in the retina. Previously, we have shown that histone deacetylase (HDAC) activity regulates Apaf-1 expression in the retina. In this study, we unravel the detailed molecular mechanism of HDAC-mediated regulation of Apaf-1 initially by use of a cell line (661W), which expresses some cone-specific genes and then by means of an ex vivo retinal explant system.

A novel antioxidant function for the tumor-suppressor gene p53 in the retinal ganglion cell.

Purpose: Recent evidence has suggested that the tumor-suppressor gene p53 has a role in regulating antioxidant response in cancer cells. This study was conducted to determine whether p53 regulates redox enzymes in a neuronal context in RGCs and whether this regulation contributes to an increased survival signal.

Methods: The expression of p53, and its putative responsive antioxidant enzymes sestrin 2, catalase, Cu/ZnSOD, and MnSOD were evaluated in the developing rat retina by immunohistochemistry and Western blot.

Histone deacetylase activity regulates apaf-1 and caspase 3 expression in the developing mouse retina.

Purpose: Apoptosis is a form of programmed cell death essential for both tissue development and maintenance of tissue homeostasis. Apoptosis protease activating factor (Apaf)-1 and caspase 3 are downregulated in the retina during postnatal development. The decreased expression of these genes is potentially a critical survival strategy adopted to protect against accidental cell death.

Rab11-FIP4 interacts with Rab11 in a GTP-dependent manner and its overexpression condenses the Rab11 positive compartment in HeLa cells.

We have recently identified Rab11-FIP4 as the sixth member of the Rab11-FIP family of Rab11 interacting proteins. Here, we demonstrate that Rab11-FIP4 interacts with Rab11 in a GTP-dependent manner and that its C-terminal region allows the protein to self-interact and interact with pp75/Rip11, Rab11-FIP2, and Rab11-FIP3. However, Rab11-FIP4 does not appear to interact directly with Rab coupling protein (RCP).

The novel Rab11-FIP/Rip/RCP family of proteins displays extensive homo- and hetero-interacting abilities.

The Rab11-FIP/Rip/RCP proteins are a recently described novel protein family, whose members interact with Rab GTPases that function in endosomal recycling. To date, five such proteins have been described in humans, all of which interact with Rab11, and one (RCP) also interacts with Rab4. Here, we characterise several of these proteins with respect to their ability to interact with Rab4, as well as their ability to self-interact, and to interact with each other.