Glaucoma Heritability: Molecular Mechanisms of Disease

Nanozymes for Treating Ocular Diseases

Nanozymes, characterized by their nanoscale size and enzyme-like catalytic activities, exhibit diverse therapeutic potentials, including anti-oxidative, anti-inflammatory, anti-microbial, and anti-angiogenic effects. These properties make them highly valuable in nanomedicine, particularly ocular therapy, bypassing the need for systemic delivery. Nanozymes show significant promise in tackling multi-factored ocular diseases, particularly those influenced by oxidation and inflammation, like dry eye disease, and age-related macular degeneration. Their small size, coupled with their ease of modification and integration into soft materials, facilitates the effective penetration of ocular barriers, thereby enabling targeted or prolonged therapy within the eye. This review is dedicated to exploring ocular diseases that are intricately linked to oxidation and inflammation, shedding light on the role of nanozymes in managing these conditions. Additionally, recent studies elucidating advanced applications of nanozymes in ocular therapeutics, along with their integration with soft materials for disease management, are discussed. Finally, this review outlines directions for future investigations aimed at bridging the gap between nanozyme research and clinical applications.

Modeling complex age-related eye disease

Modeling complex eye diseases like age-related macular degeneration (AMD) and glaucoma poses significant challenges, since these conditions depend highly on age-related changes that occur over several decades, with many contributing factors remaining unknown. Although both diseases exhibit a relatively high heritability of >50%, a large proportion of individuals carrying AMD- or glaucoma-associated genetic risk variants will never develop these diseases. Furthermore, several environmental and lifestyle factors contribute to and modulate the pathogenesis and progression of AMD and glaucoma. Several strategies replicate the impact of genetic risk variants, pathobiological pathways and environmental and lifestyle factors in AMD and glaucoma in mice and other species. In this review we will primarily discuss the most commonly available mouse models, which have and will likely continue to improve our understanding of the pathobiology of age-related eye diseases. Uncertainties persist whether small animal models can truly recapitulate disease progression and vision loss in patients, raising doubts regarding their usefulness when testing novel gene or drug therapies. We will elaborate on concerns that relate to shorter lifespan, body size and allometries, lack of macula and a true lamina cribrosa, as well as absence and sequence disparities of certain genes and differences in their chromosomal location in mice. Since biological, rather than chronological, age likely predisposes an organism for both glaucoma and AMD, more rapidly aging organisms like small rodents may open up possibilities that will make research of these diseases more timely and financially feasible. On the other hand, due to the above-mentioned anatomical and physiological features, as well as pharmacokinetic and -dynamic differences small animal models are not ideal to study the natural progression of vision loss or the efficacy and safety of novel therapies. In this context, we will also discuss the advantages and pitfalls of alternative models that include larger species, such as non-human primates and rabbits, patient-derived retinal organoids, and human organ donor eyes.

Functional role of translocator protein and its ligands in ocular diseases (Review)

The 18 kDa translocator protein (TSPO) is an essential outer mitochondrial membrane protein that is responsible for mitochondrial transport, maintenance of mitochondrial homeostasis and normal physiological cell function. The role of TSPO in the pathogenesis of ocular diseases is a growing area of interest. More notably, TSPO exerts positive effects in regulating various pathophysiological processes, such as the inflammatory response, oxidative stress, steroid synthesis and modulation of microglial function, in combination with a variety of specific ligands such as 1‑(2‑chlorophenyl‑N‑methylpropyl)‑3‑isoquinolinecarboxamide, 4'‑chlorodiazepam and XBD173. In the present review, the expression of TSPO in ocular tissues and the functional role of TSPO and its ligands in diverse ocular diseases was discussed.

Tongqiao Mingmu formula alleviates retinal ganglion cell autophagy through PI3K/AKT/mTOR pathway

Glaucoma is a severe blindness-causing optic nerve disease characterized by a loss of retinal ganglion cells (RGCs). Previous studies have shown that the Tongqiao Mingmu (TQMM) formula can reduce retinal and optic nerve damage, but its mechanism of action requires further elucidation. In this study, an RGC injury model was prepared using glutamate and then treated with serum-containing drug from the TQMM formula (hereafter called "TQMM formula serum"). In the glutamate-induced RGC injury model, cell viability decreased with an increase in glutamate concentration, whereas the expression of autophagy-related biomarkers LC3 and Belicin-1 increased. An adenovirus transfection experiment revealed that glutamate markedly promoted autophagic flux in RGCs. Notably, TQMM formula serum inhibited the expression of autophagy-related biomarkers, reduced autophagy flux, and reversed the damage caused by glutamate to RGCs. Furthermore, the PI3K inhibitor LY294002 was used to intervene in the RGC autophagy model and was found to suppress the PI3K/AKT/mTOR pathway and enhance RGC autophagy. However, TQMM formula serum could generate an opposite effect and upregulate the expressions of the PI3K/AKT/mTOR pathway genes and proteins. In conclusion, the TQMM formula can prevent glutamate-induced autophagy in RGCs, possibly by activating the PI3K/AKT/mTOR pathway and reducing the expression of autophagy-related biomarkers LC3 and Belicin-1 to attenuate autophagy and maintain RGC viability.

A rare optineurin mutation in an Indian family with coexistence of JOAG and PCG

Purpose

This study focused on the genetic screening of Myocilin (MYOC), Cytochrome P450 family 1 subfamily B member 1 (CYP1B1), Optineurin (OPTN), and SIX homeobox 6 (SIX6) genes in a family with coexistence of primary congenital glaucoma (PCG) and juvenile open-angle glaucoma (JOAG).

Methods

Sanger sequencing was used to examine the coding region of all four genes. Six different online available algorithms were used for the pathogenicity prediction of missense variant. Structural analysis was done using Garnier-Osguthorpe-Robson (GOR), PyMol, ChimeraX, and Molecular Dynamic (MD) Simulations (using Graphics Processing Unit (GPU)-enabled Desmond module of Schrödinger).

Results

There were a total of three sequence variants within the family. All seven algorithms determined that a single mutation, G538E, in the OPTN gene is pathogenic. The loops connecting the strands became more flexible, as predicted structurally and functionally by pathogenic mutations. Mutations create perturbations and conformational rearrangements in proteins, hence impairing their functioning.

Conclusion

In this study, we describe a North Indian family in which members were having JOAG and PCG due to a rare homozygous/heterozygous mutation in OPTN. The coexistence of two types of glaucoma within a single pedigree suggests that certain OPTN mutations may be responsible for the onset of different glaucoma phenotypes.

Pathologically high intraocular pressure induces mitochondrial dysfunction through Drp1 and leads to retinal ganglion cell PANoptosis in glaucoma

Glaucoma is a common neurodegenerative disease characterized by progressive retinal ganglion cell (RGC) loss and visual field defects. Pathologically high intraocular pressure (ph-IOP) is an important risk factor for glaucoma, and it triggers molecularly distinct cascades that control RGC death and axonal degeneration. Dynamin-related protein 1 (Drp1)-mediated abnormalities in mitochondrial dynamics are involved in glaucoma pathogenesis; however, little is known about the precise pathways that regulate RGC injury and death. Here, we aimed to investigate the role of the ERK1/2-Drp1-reactive oxygen species (ROS) axis in RGC death and the relationship between Drp1-mediated mitochondrial dynamics and PANoptosis in ph-IOP injury. Our results suggest that inhibiting the ERK1/2-Drp1-ROS pathway is a potential therapeutic strategy for treating ph-IOP-induced injuries. Furthermore, inhibiting Drp1 can regulate RGC PANoptosis by modulating caspase3-dependent, nucleotide-binding oligomerization domain-like receptor-containing pyrin domain 3(NLRP3)-dependent, and receptor-interacting protein (RIP)-dependent pathways in the ph-IOP model. Overall, our findings provide new insights into possible protective interventions that could regulate mitochondrial dynamics to improve RGC survival.

Lack of Association of Polymorphism Located Upstream of ABCA1 (rs2472493), in FNDC3B (rs7636836), and Near ANKRD55–MAP3K1 Genes (rs61275591) in Primary Open-Angle Glaucoma Patients of Saudi Origin

Polymorphisms rs2472493 near ABCA1, rs7636836 in FNDC3B, and rs61275591 near the ANKRD55–MAP3K1 genes were previously reported to exhibit genome-wide significance in primary open-angle glaucoma (POAG). Since these polymorphisms have not been investigated in the Arab population of Saudi Arabia, we examined their association with POAG in a Saudi cohort. Genotyping was performed in 152 POAG cases and 246 controls using Taqman real-time assays and their associations with POAG and clinical markers, such as intraocular pressure, cup/disc ratio, and the number of antiglaucoma medications, were tested by statistical methods. There was no association observed between POAG and the minor allele frequencies of rs2472493[G], rs7636836[T], or rs61275591[A]. None of the genetic models such as co-dominant, dominant, recessive, over-dominant, and log-additive demonstrated any genotype link. The Rs2472493 genotype showed a modest association (p = 0.044) with the number of antiglaucoma medications in the POAG group, but no significant genotype effect on post hoc analysis. In addition, a G-T allelic haplotype of rs2472493 (ABCA1) and rs7636836 (FNDC3B) did show an over two-fold increased risk of POAG (odds ratio = 2.18), albeit non-significantly (p = 0.092). Similarly, no other allelic haplotype of the three variants showed any significant association with POAG. Our study did not replicate the genetic association of rs2472493 (ABCA1), rs763683 (FNDC3B), and rs61275591 (ANKRD55–MAP3K1) in POAG and related clinical phenotypes, suggesting that these polymorphisms are not associated with POAG in a Saudi cohort of Arab ethnicity. However, large population-based multicenter studies are needed to validate these results.

Relationship between high dose intake of vitamin B12 and glaucoma: Evidence from NHANES 2005-2008 among United States adults

Objective

Glaucoma has currently become the second leading cause of blindness in the world. Serum vitamin B12 level has been found to be involved in the development and progression of glaucoma. We performed the present study to confirm this association.

Methods

This cross-sectional study included 594 participants aged 40 years and older in the National Health and Nutrition Examination Survey (NHANES) from 2005 to 2008. Retinal imaging was performed using the Ophthalmic Digital Imaging system (Retinography) to assess the retina for the presence of features of glaucomatous lesions. Logistic regression models were used to assess the association between dietary vitamin intake and glaucoma.

Results

After screening, 594 subjects were finally included. Among all vitamin intakes, we observed significant differences between the two groups for vitamin B12 intake (5.93 vs. 4.77 mg, p = 0.033). According to the logistic regression results, the intake of vitamin B12 was significantly positively associated with glaucoma (model 1: OR = 1.078, 95% CI = 1.019-1.141; model 2: OR = 1.092, 95% CI = 1.031-1.158; model 3: OR = 1.092, 95% CI = 1.029-1.158). After performing a quantile regression, we observed a significant positive association between vitamin B12 intake and incident glaucoma in the fourth quartile (model 1: OR = 1.133, 95% CI = 1.060-1.210; model 2: OR = 1.141, 95% CI = 1.072-1.215; model 3: OR = 1.146, 95% CI = 1.071-1.226).

Conclusions

Therefore, the above results, high-dose intake of vitamin B12 may promote the development of glaucoma.

Clinical pharmacology and pharmacogenetics of prostaglandin analogues in glaucoma

Glaucoma is the main cause of irreversible visual loss worldwide, and comprises a group of progressive, age-related, and chronic optic neuropathies. Prostaglandin analogs are considered a first-line treatment in the management of glaucoma and have the best efficacy in reducing intraocular pressure. When comparing these therapeutic agents between them, long-term therapy with 0.03% bimatoprost is the most effective followed by treatment with 0.005% latanoprost and 0.004% travoprost. The prevalence of adverse events is lower for latanoprost than for other prostaglandin analogs. However, some patients do not respond to the treatment with prostaglandin analogs (non-responders). Intraocular pressure-lowering efficacy differs significantly between individuals partly owing to genetic factors. Rs1045642 in ABCB1, rs4241366 in SLCO2A1, rs9503012 in GMDS, rs10306114 in PTGS1, rs11568658 in MRP4, rs10786455 and rs6686438 in PTGFR were reported to be positive with the response to prostaglandin analogs in patients with glaucoma. A negative association was found between single nucleotide polymorphisms of PTGFR (rs11578155 and rs6672484) and the response to prostaglandin analogs in patients with glaucoma. The current review is an analysis of the information relevant to prostaglandin analog treatments based on previous literatures. It describes in detail the clinical pharmacology and pharmacogenetics of drugs belonging to this therapeutical class to provide a sound pharmacological basis for their proper use in ophthalmological clinical practice.

Glucocorticoid therapy reduces ocular hypertension in active moderate-severe thyroid-associated orbitopathy

PURPOSE

Ocular hypertension (OHT) is an important clinical feature of thyroid-associated orbitopathy (TAO).While the prevalence and outcome of OHT in TAO remains unclear. This study investigates this in moderate-severe active TAO.

METHODS

Sixty-eight patients with active moderate-severe TAO were recruited, 49 of whom were treated with 12-week GC therapy.The clinical and biochemical parameters were collected.Treatment outcomes were evaluated after GC therapy.

RESULTS

The prevalence of OHT was 44.85% in moderate-severe active TAO patients,including 81.97% of mild hypertension, 13.11% of moderate hypertension and 4.92% of severe hypertension. Clinical and biochemical parameters had no significant difference between OHT patients and non-OHT patients,such as age, sex distributions, smoking status, the kind and the duration of thyroid disease,the duration of eye symptoms and the level of FT3,FT4,TSH, TR-Ab, and Tpo-Ab, Tg-Ab(all P > 0.05). After GC therapy,the intraocular pressure(IOP) in OHT eyes decreased significantly (P < 0.05), while IOP in non-OHT eyes remained unchanged (P > 0.05).There was no significant difference in CAS and the effective rate of GC therapy between OHT eyes and non-OHT eyes (P > 0.05).

CONCLUSION

In moderate-severe active TAO, the prevalence of OHT was 44.85%, most of which were mild hypertension.OHT was relieved by GC therapy,which had no effect on the efficacy of GC therapy.Our results will enhance physicians' confidence in GC therapy.

The Intertwined Roles of Oxidative Stress and Endoplasmic Reticulum Stress in Glaucoma

Glaucoma is the leading cause of irreversible blindness worldwide, and the burden of the disease continues to grow as the global population ages. Currently, the only treatment option is to lower intraocular pressure. A better understanding of glaucoma pathogenesis will help us to develop novel therapeutic options. Oxidative stress has been implicated in the pathogenesis of many diseases. Oxidative stress occurs when there is an imbalance in redox homeostasis, with reactive oxygen species producing processes overcoming anti-oxidant defensive processes. Oxidative stress works in a synergistic fashion with endoplasmic reticulum stress, to drive glaucomatous damage to trabecular meshwork, retinal ganglion cells and the optic nerve head. We discuss the oxidative stress and endoplasmic reticulum stress pathways and their connections including their key intermediary, calcium. We highlight therapeutic options aimed at disrupting these pathways and discuss their potential role in glaucoma treatment.

Association of GSTO1, GSTO2, GSTP1, GPX1 and SOD2 polymorphism with primary open angle glaucoma

It is becoming increasingly evident that oxidative stress has a supporting role in pathophysiology and progression of primary open angle glaucoma (POAG). The aim of our study was to assess the association between polymorphisms in genes encoding enzymes involved in redox homeostasis, mitochondrial superoxide dismutase (SOD2), glutathione peroxidase (GPX1) and glutathione transferases (GSTs) with susceptibility to POAG. Single nucleotide polymorphisms in GST omega (GSTO1rs4925, GSTO2 rs156697), pi 1 (GSTP1 rs1695), as well as GPX1 (rs1050450) and SOD2 (rs4880) were determined by quantitative polymerase chain reaction (qPCR) in 102 POAG patients and 302 respective controls. The risk for POAG development was noted in carriers of both GSTO2*GG and GSTO1*AA variant genotypes (OR = 8.21, p = 0.002). Individuals who carried GPX1*TT and SOD2*CC genotypes had also an increased risk of POAG development but without significance after Bonferroni multiple test correction (OR = 6.66, p = 0.005). The present study supports the hypothesis that in combination, GSTO1/GSTO2, modulate the risk of primary open angle glaucoma.