Although biomechanical changes of the trabecular meshwork (TM) are important to the pathogenesis of glucocorticoids-induced ocular hypertension (GC-OHT), there is a knowledge gap in the underlying molecular mechanisms of the development of it. In this study, we performed intravitreal triamcinolone injection (IVTA) in one eye of 3 rhesus macaques. Following IVTA, we assessed TM stiffness using atomic force microscopy and investigated changes in proteomic and miRNA expression profiles. One of 3 macaques developed GC-OHT with a difference in intraocular pressure of 4.2 mmHg and a stiffer TM with a mean increase in elastic moduli of 0.60 kPa versus the non-injected control eye. In the IVTA-treated eyes, proteins associated with extracellular matrix remodeling, cytoskeletal rearrangement, and mitochondrial oxidoreductation were significantly upregulated. The significantly upregulated miR-29b and downregulated miR-335-5p post-IVTA supported the role of oxidative stress and mitophagy in the GC-mediated biomechanical changes in TM, respectively. The significant upregulation of miR-15/16 cluster post-IVTA may indicate a resultant TM cell apoptosis contributing to the increase in outflow resistance. Despite the small sample size, these results expand our knowledge of GC-mediated responses in the TM and furthermore, may help explain steroid responsiveness in clinical settings.

Glaucoma is the leading cause of irreversible blindness globally. The most prevalent subtype, Primary Open Angle Glaucoma (POAG), is characterized by increased intraocular pressure (IOP), damage to the optic nerve head and irreversible visual loss. IOP increases aqueous humor (AqH) outflow is reduced through the trabecular meshwork (TM) and Schlemm\'s canal (SC). Increased outflow resistance is partly due to TM/SC dysregulation, including loss of normal trabecular meshwork cell (TMC) function, following increased levels of oxidative stress within TMC, dysregulated extracellular matrix (ECM) deposition and remodeling alongside alterations in TMC phenotype and apoptosis. Current widely available POAG treatments do not target the aberrant expression of ECM in the TM directly. As a result, most drug treatments can fail as the underlying pathological process continues unabated. Rho-kinase inhibitors have demonstrated the benefit of restoring TM/SC function, however there is a clear need to develop further treatment strategies that can target the underlying cellular processes which become dysregulated within the TMC during POAG pathogenesis. Vitamin D is suggested to be beneficial in alleviating the symptoms of fibrosis and inflammation in soft tissues. It has important functions in many major organ systems, including regulation of calcium, phosphate and parathyroid hormone. Evidence suggests that Vitamin D3 modulates ECM turnover through the conventional TGFβ-SMAD signaling, which is associated with the development of POAG. The link between Vitamin D3, inflammation and fibrosis within ocular tissues will be discussed and the potential roles of Vitamin D3 in the management of POAG patients will be explored within this review.

Glaucoma is the leading cause of irreversible blindness globally, with Primary open angle glaucoma (POAG) being the commonest subtype. POAG is characterized by an increase in intraocular pressure (IOP), leading to optic nerve damage and subsequent visual field defects. Despite the clinical burden this disease poses, current therapies aim to reduce IOP rather than targeting the underling pathogenesis. Although the pathogenesis of POAG is complex, the culprit for this increase in IOP resides in the aqueous humour (AH) outflow pathway; the trabecular meshwork (TM) and Schlemm\'s canal. Dysfunction in these tissues is due to inherent mitochondrial dysfunction, calcium influx sensitivity, increase in reactive oxygen species (ROS) production, TGFβ-2 induction, leading to a sustained inflammatory response. Magnesium is the second most common intracellular cation, and is a major co-factor in over 300 reactions, being highly conserved within energy-dependent organelles such as the mitochondria. Magnesium deficiency has been observed in POAG and is linked to inflammatory and fibrotic responses, as well as increased oxidative stress (OS). Magnesium supplementation been shown to reduce cellular ROS, alleviate mitochondrial dysregulation and has further antifibrotic and anti-inflammatory properties within ocular tissues, and other soft tissues prone to fibrosis, suggesting that magnesium can improve visual fields in patients with POAG. The link between magnesium deficiency and glaucoma pathogenesis as well as the potential role of magnesium supplementation in the management of patients with POAG will be explored within this review.

High-resolution imaging methods of the iridocorneal angle (ICA) will lead to enhanced understanding of aqueous humor outflow mechanisms and a characterization of the trabecular meshwork (TM) morphology at the cellular level will help to better understand glaucoma mechanics (e.g., cellular level biomechanics of the particulate glaucomas). This information will translate into immense clinical value, leading to more informed and customized treatment selection, and improved monitoring of procedural interventions that lower intraocular pressure (IOP). Given ICA anatomy, imaging modalities that yield intrinsic optical sectioning or 3D imaging capability will be useful to aid in the visualization of TM layers. This minireview examines advancements in imaging the ICA in high-resolution.

Primary open angle glaucoma (POAG) is a progressive and chronic disease exhibiting many of the features of fibrosis. The extracellular matrix (ECM) in the trabecular meshwork (TM) undergoes extensive remodeling and enhanced rigidity, resembling fibrotic changes. In addition, there are changes associated with myofibroblast activation and cell contractility that further drives tissue fibrosis and stiffening. This review discusses what is known about the integrins in the TM and their involvement in fibrotic processes.

The trabecular meshwork (TM) from primary open-angle glaucoma (POAG) cases has been found to contain decreased levels of intracellular plasmalogens. Plasmalogens are a subset of lipids involved in diverse cellular processes such as intracellular signaling, membrane asymmetry, and protein regulation. Proper plasmalogen biosynthesis is regulated by rate-limiting enzyme fatty acyl-CoA reductase (Far1). ATPase phospholipid transporting 8B2 (ATP8B2) is a type IV P-type ATPase responsible for the asymmetric distribution of plasmalogens between the intracellular and extracellular leaflets of the plasma membranes. Here we describe the methodology for extraction and culturing of TM cells from corneal tissue and subsequent downregulation of ATP8B2 using siRNA transfection. Further quantification and downstream effects of ATP8B2 gene knockdown will be analyzed utilizing immunoblotting techniques.

Members of the Rho family of small monomeric GTPases regulate a plethora of critical cellular functions including gene expression, cell cycle progression, and the dynamic modeling of the actin cytoskeleton. Diversity among Rho family members is derived, in part, from variations in their subcellular distribution. Localization of newly synthesized (naïve) Rho proteins to target subcellular compartments is largely governed by lipid modifications, including posttranslational prenylation. Here, using well-established and widely available contemporary methodologies, detailed protocols by which to semiquantitatively evaluate the functional consequence of posttranslational prenylation in human trabecular meshwork cells are described. We propose the novel concept that posttranslational prenylation itself is a key regulator of mammalian Rho GTPase protein expression and turnover.

UNASSIGNED: Glucocorticoid-induced glaucoma (GIG) is a prevalent complication associated with glucocorticoids (GCs), resulting in irreversible blindness. GIG is characterized by the abnormal deposition of extracellular matrix (ECM) in the trabecular meshwork (TM), elevation of intraocular pressure (IOP), and loss of retinal ganglion cells (RGCs). The objective of this study is to investigate the effects of nicotinamide riboside (NR) on TM in GIG.
UNASSIGNED: Primary human TM cells (pHTMs) and C57BL/6J mice responsive to GCs were utilized to establish in vitro and in vivo GIG models, respectively. The study assessed the expression of ECM-related proteins in TM and the functions of pHTMs to reflect the effects of NR. Mitochondrial morphology and function were also examined in the GIG cell model. GIG progression was monitored through IOP, RGCs, and mitochondrial morphology. Intracellular nicotinamide adenine dinucleotide (NAD+) levels of pHTMs were enzymatically assayed.
UNASSIGNED: NR significantly prevented the expression of ECM-related proteins and alleviated dysfunction in pHTMs after dexamethasone treatment. Importantly, NR protected damaged ATP synthesis, preventing overexpression of mitochondrial reactive oxygen species (ROS), and also protect against decreased mitochondrial membrane potential induced by GCs in vitro. In the GIG mouse model, NR partially prevented the elevation of IOP and the loss of RGCs. Furthermore, NR effectively suppressed the excessive expression of ECM-associated proteins and mitigated mitochondrial damage in vivo.
UNASSIGNED: Based on the results, NR effectively enhances intracellular levels of NAD+, thereby mitigating abnormal ECM deposition and TM dysfunction in GIG by attenuating mitochondrial damage induced by GCs. Thus, NR has promising potential as a therapeutic candidate for GIG treatment.

OBJECTIVE: To evaluate structural alterations and healing responses in the trabecular meshwork region with optical coherence tomography (AS-OCT) following after gonioscopy assisted transluminal trabeculotomy (GATT) and microincisional trabeculectomy (MIT).
METHODS: 73 eyes of 67 patients (M:F = 45:22) with ≥6 months of follow-up after MIT (n = 41) or GATT (n = 32) with or without combined cataract surgery were included for this prospective study. The angle as seen on AS-OCT at 1, 3, 6 months after surgery were evaluated for structural alterations like peripheral anterior synechiae (PAS), hyphema, and hyperreflective scarring responses. The scarring was graded according to the linear extent measured from the centre of the trabecular meshwork (TM) gutter to the sclera/cornea as mild (<250μ), moderate (250-500μ), and severe(˃500μ), while the pattern of scarring was graded as open saucer/gutter, closed gutter, and trench pattern. The association of the need for medication or surgical outcome and clinical variables and AS-OCT parameters including the pattern and severity of scarring were analysed using multivariate regression.
RESULTS: All eyes achieved significant reduction of IOP and number of medications with a final IOP of 15±3.2mm Hg at a mean follow-up of 8±32. months. While mild scarring was seen more common in MIT, severe scarring was seen in >65% of GATT eyes compared to 31% of MIT eye, p<0.001. An open saucer was equally seen in MIT and GATT while the trench pattern was more commonly seen in GATT eyes (>50%). Severe scarring in a trench pattern seemed to predict the need for medications for IOP control, though they independently did not seem to influence the final IOP or surgical outcome.
CONCLUSIONS: A severe form of scarring in a trench pattern on AS-OCT predicted the need for glaucoma medications after MIGS surgery. Regular monitoring of the scarring responses by AS-OCT and clinical examination are necessary to identify those at need for medications after MIGS.

Primary open-angle glaucoma (POAG) is a progressive optic neuropathy with a complex, multifactorial aetiology. Raised intraocular pressure (IOP) is the most important clinically modifiable risk factor for POAG. All current pharmacological agents target aqueous humour dynamics to lower IOP. Newer therapeutic agents are required as some patients with POAG show a limited therapeutic response or develop ocular and systemic side effects to topical medication. Elevated IOP in POAG results from cellular and molecular changes in the trabecular meshwork driven by increased levels of transforming growth factor β (TGFβ) in the anterior segment of the eye. Understanding how TGFβ affects both the structural and functional changes in the outflow pathway and IOP is required to develop new glaucoma therapies that target the molecular pathology in the trabecular meshwork. In this study, we evaluated the effects of TGF-β1 and -β2 treatment on miRNA expression in cultured human primary trabecular meshwork cells. Our findings are presented in terms of specific miRNAs (miRNA-centric), but given miRNAs work in networks to control cellular pathways and processes, a pathway-centric view of miRNA action is also reported. Evaluating TGFβ-responsive miRNA expression in trabecular meshwork cells will further our understanding of the important pathways and changes involved in the pathogenesis of glaucoma and could lead to the development of miRNAs as new therapeutic modalities in glaucoma.