First-in-human phase I study of ISTH0036, an antisense oligonucleotide selectively targeting transforming growth factor beta 2 (TGF-β2), in subjects with open-angle glaucoma undergoing glaucoma filtration surgery

Corneal fibrosis: From in vitro models to current and upcoming drug and gene medicines

Fibrotic diseases are characterised by myofibroblast differentiation, uncontrolled pathological extracellular matrix accumulation, tissue contraction, scar formation and, ultimately tissue / organ dysfunction. The cornea, the transparent tissue located on the anterior chamber of the eye, is extremely susceptible to fibrotic diseases, which cause loss of corneal transparency and are often associated with blindness. Although topical corticosteroids and antimetabolites are extensively used in the management of corneal fibrosis, they are associated with glaucoma, cataract formation, corneoscleral melting and infection, imposing the need of far more effective therapies. Herein, we summarise and discuss shortfalls and recent advances in in vitro models (e.g. transforming growth factor-β (TGF-β) / ascorbic acid / interleukin (IL) induced) and drug (e.g. TGF-β inhibitors, epigenetic modulators) and gene (e.g. gene editing, gene silencing) therapeutic strategies in the corneal fibrosis context. Emerging therapeutical agents (e.g. neutralising antibodies, ligand traps, receptor kinase inhibitors, antisense oligonucleotides) that have shown promise in clinical setting but have not yet assessed in corneal fibrosis context are also discussed.

Introduction of sugar-modified nucleotides into CpG-containing antisense oligonucleotides inhibits TLR9 activation

Antisense oligonucleotides (ASOs) are synthetic single-stranded oligonucleotides that bind to RNAs through Watson-Crick base pairings. They are actively being developed as therapeutics for various human diseases. ASOs containing unmethylated deoxycytidylyl-deoxyguanosine dinucleotide (CpG) motifs are known to trigger innate immune responses via interaction with toll-like receptor 9 (TLR9). However, the TLR9-stimulatory properties of ASOs, specifically those with lengths equal to or less than 20 nucleotides, phosphorothioate linkages, and the presence and arrangement of sugar-modified nucleotides-crucial elements for ASO therapeutics under development-have not been thoroughly investigated. In this study, we first established SY-ODN18, an 18-nucleotide phosphorothioate oligodeoxynucleotide with sufficient TLR9-stimulatory activity. We demonstrated that an unmethylated CpG motif near its 5'-end was indispensable for TLR9 activation. Moreover, by utilizing various sugar-modified nucleotides, we systematically generated model ASOs, including gapmer, mixmer, and fully modified designs, in accordance with the structures of ASO therapeutics. Our results illustrated that introducing sugar-modified nucleotides in such designs significantly reduces TLR9-stimulatory activity, even without methylation of CpG motifs. These findings would be useful for drug designs on several types of ASOs.

Advances and Challenges in Targeting TGF-β Isoforms for Therapeutic Intervention of Cancer: A Mechanism-Based Perspective

The TGF-β family is a group of 25 kDa secretory cytokines, in mammals consisting of three dimeric isoforms (TGF-βs 1, 2, and 3), each encoded on a separate gene with unique regulatory elements. Each isoform plays unique, diverse, and pivotal roles in cell growth, survival, immune response, and differentiation. However, many researchers in the TGF-β field often mistakenly assume a uniform functionality among all three isoforms. Although TGF-βs are essential for normal development and many cellular and physiological processes, their dysregulated expression contributes significantly to various diseases. Notably, they drive conditions like fibrosis and tumor metastasis/progression. To counter these pathologies, extensive efforts have been directed towards targeting TGF-βs, resulting in the development of a range of TGF-β inhibitors. Despite some clinical success, these agents have yet to reach their full potential in the treatment of cancers. A significant challenge rests in effectively targeting TGF-βs' pathological functions while preserving their physiological roles. Many existing approaches collectively target all three isoforms, failing to target just the specific deregulated ones. Additionally, most strategies tackle the entire TGF-β signaling pathway instead of focusing on disease-specific components or preferentially targeting tumors. This review gives a unique historical overview of the TGF-β field often missed in other reviews and provides a current landscape of TGF-β research, emphasizing isoform-specific functions and disease implications. The review then delves into ongoing therapeutic strategies in cancer, stressing the need for more tools that target specific isoforms and disease-related pathway components, advocating mechanism-based and refined approaches to enhance the effectiveness of TGF-β-targeted cancer therapies.

Future directions of glaucoma treatment: emerging gene, neuroprotection, nanomedicine, stem cell, and vascular therapies

PURPOSE OF REVIEW

The aim of this article is to summarize current research on novel gene, stem cell, neuroprotective, nanomedicine, and vascular therapies for glaucoma.

RECENT FINDINGS

Gene therapy using viral vectors and siRNA have been shown to reduce intraocular pressure by altering outflow and production of aqueous humor, to reduce postsurgical fibrosis with few adverse effects, and to increase retinal ganglion cell (RGC) survival in animal studies. Stem cells may treat glaucoma by replacing or stimulating proliferation of trabecular meshwork cells, thus restoring outflow facility. Stem cells can also serve a neuroprotective effect by differentiating into RGCs or preventing RGC loss via secretion of growth factors. Other developing neuroprotective glaucoma treatments which can prevent RGC death include nicotinamide, the NT-501 implant which secretes ciliary neurotrophic factor, and a Fas-L inhibitor which are now being tested in clinical trials. Recent studies on vascular therapy for glaucoma have focused on the ability of Rho Kinase inhibitors and dronabinol to increase ocular blood flow.

SUMMARY

Many novel stem cell, gene, neuroprotective, nanomedicine, and vascular therapies have shown promise in preclinical studies, but further clinical trials are needed to demonstrate safety and efficacy in human glaucomatous eyes. Although likely many years off, future glaucoma therapy may take a multifaceted approach.

Gene therapies and gene product-based drug candidates for normalizing and preserving tissue functions in animal models of ocular hypertension and glaucoma

More than 76 million people worldwide are afflicted with the neurodegenerative eye diseases described and grouped together as glaucoma. A common feature amongst the many forms of glaucoma is chronically elevated intraocular pressure (IOP) within the anterior chamber of the eye that physically damages the retina, optic nerve and parts of the brain connected with visual perception. The mediators of the contusing raised IOP responsible for such damage and loss of vision include locally released inflammatory agents, tissue remodeling enzymes and infiltrating immune cells which damage the retinal ganglion cell (RGC) axons and eventually kill a significant number of the RGCs. Additional culprits include genetic defects of the patient that involve aberrations in receptors, enzymes and/or endogenous ligands and possible over- or under-production of the latter. Other genetic abnormalities may include issues with signal transduction machinery within key cells of critical tissues in the front (e.g. trabecular meshwork [TM] and Schlemm's canal [SC]) and back of the eye (e.g. retinal ganglion cells and their axons). Genome-wide associated studies (GWAS) coupled with next generation sequencing have provided powerful linkage of certain gene defects and polymorphic variants to the onset and progression of diseases of the tissues involved in fluid dynamics in the TM and SC, and many retinal elements (lamina cribosa, optic nerve head) at the back of the eye which cause ocular hypertension (OHT) and glaucomatous optic neuropathy (GON), respectively. Despite the availability of some drugs, fluid drainage microshunts and full surgical techniques to lower and control intraocular pressure, the major modifiable biomarker of open-angle and other forms of glaucoma, their side-effect profiles, less than optimum effectiveness and short duration of action present opportunities to clinically manage the glaucomas with next generation of treatments with high therapeutic indices, including gene therapies. Thus, identification, characterization and deployment of genetic data coupled with traditional drug discovery and novel gene replacement, gene editing and genetic engineering technologies may provide some solutions to the aforementioned problems. These aspects will be discussed in this article.

Advances in targeting the extracellular matrix for glaucoma therapy: current updates

INTRODUCTION

Elevated intraocular pressure (IOP) is a well-recognized risk factor for development of primary open angle glaucoma (POAG), a leading cause of irreversible blindness. Ocular hypertension is associated with excessive extracellular matrix (ECM) deposition in trabecular meshwork (TM) resulting in increased aqueous outflow resistance and elevated IOP. Hence, therapeutic options targeting ECM remodeling in TM to lower IOP in glaucomatous eyes are of considerable importance.

AREAS COVERED

This paper discusses the complex process of ECM regulation in TM and explores promising therapeutic targets. The role of Transforming Growth Factor-β as a central player in ECM deposition in TM is discussed. We elaborate the key regulatory processes involved in its activation, release, signaling, and cross talk with other signaling pathways including Rho GTPase, Wnt, integrin, cytokines, and renin-angiotensin-aldosterone. Further, we summarize the therapeutic agents that have been explored to target ECM dysregulation in TM.

EXPERT OPINION

Targeting molecular pathways to reduce ECM deposition and/or enhance its degradation are of considerable significance for IOP lowering. Challenges lie in pinpointing specific targets and designing drug delivery systems to precisely interact with pathologically active/inactive signaling. Recent advances in monoclonal antibodies, fusion molecules, and vectored nanotechnology offer potential solutions.

Elevated Intraocular Pressure and Glaucomatous Optic Neuropathy: Genes to Disease Mechanisms, Therapeutic Drugs, and Gene Therapies

This review article focuses on the pathogenesis of and genetic defects linked with chronic ocular hypertension (cOHT) and glaucoma. The latter ocular disease constitutes a group of ocular degenerative diseases whose hallmark features are damage to the optic nerve, apoptotic demise of retinal ganglion cells, disturbances within the brain regions involved in visual perception and considerable visual impairment that can lead to blindness. Even though a number of pharmaceuticals, surgical and device-based treatments already exist addressing cOHT associated with the most prevalent of the glaucoma types, primary open-angle glaucoma (POAG), they can be improved upon in terms of superior efficacy with reduced side-effects and with longer duration of activity. The linkage of disease pathology to certain genes via genome-wide associated studies are illuminating new approaches to finding novel treatment options for the aforementioned ocular disorders. Gene replacement, gene editing via CRISPR-Cas9, and the use of optogenetic technologies may replace traditional drug-based therapies and/or they may augment existing therapeutics for the treatment of cOHT and POAG in the future.

Recently Approved Drugs for Lowering and Controlling Intraocular Pressure to Reduce Vision Loss in Ocular Hypertensive and Glaucoma Patients

Serious vision loss occurs in patients affected by chronically raised intraocular pressure (IOP), a characteristic of many forms of glaucoma where damage to the optic nerve components causes progressive degeneration of retinal and brain neurons involved in visual perception. While many risk factors abound and have been validated for this glaucomatous optic neuropathy (GON), the major one is ocular hypertension (OHT), which results from the accumulation of excess aqueous humor (AQH) fluid in the anterior chamber of the eye. Millions around the world suffer from this asymptomatic and progressive degenerative eye disease. Since clinical evidence has revealed a strong correlation between the reduction in elevated IOP/OHT and GON progression, many drugs, devices, and surgical techniques have been developed to lower and control IOP. The constant quest for new pharmaceuticals and other modalities with superior therapeutic indices has recently yielded health authority-approved novel drugs with unique pharmacological signatures and mechanism(s) of action and AQH drainage microdevices for effectively and durably treating OHT. A unique nitric oxide-donating conjugate of latanoprost, an FP-receptor prostaglandin (PG; latanoprostene bunod), new rho kinase inhibitors (ripasudil; netarsudil), a novel non-PG EP2-receptor-selective agonist (omidenepag isopropyl), and a form of FP-receptor PG in a slow-release intracameral implant (Durysta) represent the additions to the pharmaceutical toolchest to mitigate the ravages of OHT. Despite these advances, early diagnosis of OHT and glaucoma still lags behind and would benefit from further concerted effort and attention.

Nanotechnology Lighting the Way for Gene Therapy in Ophthalmopathy: From Opportunities toward Applications

Hereditary ophthalmopathy is a well-described threat to human visual health affecting millions of people. Gene therapy for ophthalmopathy has received widespread attention with the increasing understanding of pathogenic genes. Effective and safe delivery of accurate nucleic acid drugs (NADs) is the core of gene therapy. Efficient nanodelivery and nanomodification technologies, appropriate targeted genes, and the choice of drug injection methods are the guiding lights of gene therapy. Compared with traditional drugs, NADs can specifically change the expression of specific genes or restore the normal function of mutant genes. Nanodelivery carriers can improve targeting and nanomodification can improve the stability of NADs. Therefore, NADs, which can fundamentally solve pathogeny, hold great promise in the treatment of ophthalmopathy. This paper reviews the limitations of ocular disease treatment, discusses the classification of NADs in ophthalmology, reveals the delivery strategies of NADs to improve bioavailability, targeting, and stability, and summarizes the mechanisms of NADs in ophthalmopathy.

RNA-targeting strategies as a platform for ocular gene therapy

Genetic medicine is offering hope as new therapies are emerging for many previously untreatable diseases. The eye is at the forefront of these advances, as exemplified by the approval of Luxturna® by the United States Food and Drug Administration (US FDA) in 2017 for the treatment of one form of Leber Congenital Amaurosis (LCA), an inherited blindness. Luxturna® was also the first in vivo human gene therapy to gain US FDA approval. Numerous gene therapy clinical trials are ongoing for other eye diseases, and novel delivery systems, discovery of new drug targets and emerging technologies are currently driving the field forward. Targeting RNA, in particular, is an attractive therapeutic strategy for genetic disease that may have safety advantages over alternative approaches by avoiding permanent changes in the genome. In this regard, antisense oligonucleotides (ASO) and RNA interference (RNAi) are the currently popular strategies for developing RNA-targeted therapeutics. Enthusiasm has been further fuelled by the emergence of clustered regularly interspersed short palindromic repeats (CRISPR)-CRISPR associated (Cas) systems that allow targeted manipulation of nucleic acids. RNA-targeting CRISPR-Cas systems now provide a novel way to develop RNA-targeted therapeutics and may provide superior efficiency and specificity to existing technologies. In addition, RNA base editing technologies using CRISPR-Cas and other modalities also enable precise alteration of single nucleotides. In this review, we showcase advances made by RNA-targeting systems for ocular disease, discuss applications of ASO and RNAi technologies, highlight emerging CRISPR-Cas systems and consider the implications of RNA-targeting therapeutics in the development of future drugs to treat eye disease.

[The value of lamina cribrosa in the diagnosis and treatment of glaucoma. Remodeling of lamina cribrosa collagen and approaches to its therapeutic treatment]

Among the first structures suffering damage with an increase in intraocular pressure (IOP) and in early stage of glaucoma are the lamina cribrosa (LC) and peripapillary sclera (ppScl). Changes in these structures occur at the molecular and cellular level. Extracellular matrix (ECM) is the basis of connective tissue, provides mechanical support for the cells, facilitates intercellular interactions and transport of chemicals, including in LC and ppScl. Mechanical stress causes remodeling and disorganization of the ECM, which leads to changes in the structure of the tissue itself, an increase in its rigidity and a decrease in elasticity. Taking into account the molecular and cellular mechanisms of damage to LC and ppScl, various researchers have developed strategies and tactics for therapeutic intervention on these structures, contributing to a decrease in ECM secretion and, as a consequence, suspension of their remodeling. These approaches may in the future form the basis for the treatment of glaucomatous optic neuropathy.

Transforming growth factor-β signaling: from tumor microenvironment to anticancer therapy

Transforming growth factor-β (TGF-β) signaling is an important pathway for promoting the pathogenesis of inflammatory diseases, including cancer. The roles of TGF-β signaling are heterogeneous and versatile in cancer development and progression, both anticancer and protumoral actions are reported. Interestingly, increasing evidence suggests that TGF-β enhances disease progression and drug resistance via immune-modulatory actions in the tumor microenvironment (TME) of solid tumors. A better understanding of its regulatory mechanisms in the TME at the molecular level can facilitate the development of precision medicine to block the protumoral actions of TGF-β in the TME. Here, the latest information about the regulatory mechanisms and translational research of TGF-β signaling in the TME for therapeutic development had been summarized.

TGF-beta signal transduction: biology, function and therapy for diseases

The transforming growth factor beta (TGF-β) is a crucial cytokine that get increasing concern in recent years to treat human diseases. This signal controls multiple cellular responses during embryonic development and tissue homeostasis through canonical and/or noncanonical signaling pathways. Dysregulated TGF-β signal plays an essential role in contributing to fibrosis via promoting the extracellular matrix deposition, and tumor progression via inducing the epithelial-to-mesenchymal transition, immunosuppression, and neovascularization at the advanced stage of cancer. Besides, the dysregulation of TGF-beta signal also involves in other human diseases including anemia, inflammatory disease, wound healing and cardiovascular disease et al. Therefore, this signal is proposed to be a promising therapeutic target in these diseases. Recently, multiple strategies targeting TGF-β signals including neutralizing antibodies, ligand traps, small-molecule receptor kinase inhibitors targeting ligand-receptor signaling pathways, antisense oligonucleotides to disrupt the production of TGF-β at the transcriptional level, and vaccine are under evaluation of safety and efficacy for the forementioned diseases in clinical trials. Here, in this review, we firstly summarized the biology and function of TGF-β in physiological and pathological conditions, elaborated TGF-β associated signal transduction. And then, we analyzed the current advances in preclinical studies and clinical strategies targeting TGF-β signal transduction to treat diseases.

Selective Activation of the Wnt-Signaling Pathway as a Novel Therapy for the Treatment of Diabetic Retinopathy and Other Retinal Vascular Diseases

Retinal ischemia, often associated with various disorders such as diabetic retinopathy (DR), retinal vein occlusion, glaucoma, optic neuropathies, stroke, and other retinopathies, is a major cause of visual impairment and blindness worldwide. As proper blood supply to the retina is critical to maintain its high metabolic demand, any impediment to blood flow can lead to a decrease in oxygen supply, resulting in retinal ischemia. In the pathogenesis of DR, including diabetic macular edema (DME), elevated blood glucose leads to blood-retina barrier (BRB) disruptions, vascular leakage, and capillary occlusion and dropouts, causing insufficient delivery of oxygen to the retina, and ultimately resulting in visual impairment. Other potential causes of DR include neuronal dysfunction in the absence of vascular defect, genetic, and environmental factors. The exact disease progression remains unclear and varies from patient to patient. Vascular leakage leading to edema clearly links to visual impairment and remains an important target for therapy. Despite recent advances in the treatment of DME and DR with anti-VEGFs, effective therapies with new mechanisms of action to address current treatment limitations regarding vessel regeneration and reperfusion of ischemic retinal areas are still needed. The Wnt signaling pathway plays a critical role in proper vascular development and maintenance in the retina, and thus provides a novel therapeutic approach for the treatment of diabetic and other retinopathies. In this review, we summarize the potential of this pathway to address treatment gaps with current therapies, its promise as a novel and potentially disease modifying therapy for patients with DR and opportunities in other retinal vascular diseases.

XEN45 Gelstent Implantation in the Treatment of Glaucoma Secondary to Fuchs Uveitis Syndrome

PURPOSE

Evaluation of treatment efficacy of XEN45 gelstent for glaucoma secondary to Fuchs uveitis syndrome (FUS).

METHODS

This retrospective case series evaluated patients with glaucoma secondary to FUS, who underwent XEN45 implantation. Complete success was defined as IOP lowering of ≥ 20% and cutoff IOP at ≤18 mmHg. Success was qualified if additional glaucoma medication was necessary. Additional glaucoma surgery except for needling and open bleb revision was regarded as failure.

RESULTS

Twelve eyes of 12 patients were included. Qualified and complete success rates were 50% after one year (n = 10). Qualified success was achieved in 66.6% of patients with 33.3% of patients achieving complete success after two years (n = 6).

CONCLUSIONS

XEN45 implantation had some success in the treatment of glaucoma secondary to FUS, but needling was frequently necessary to improve outcome.

TGF-β Superfamily Signaling in the Eye: Implications for Ocular Pathologies

The TGF-β signaling pathway plays a crucial role in several key aspects of development and tissue homeostasis. TGF-β ligands and their mediators have been shown to be important regulators of ocular physiology and their dysregulation has been described in several eye pathologies. TGF-β signaling participates in regulating several key developmental processes in the eye, including angiogenesis and neurogenesis. Inadequate TGF-β signaling has been associated with defective angiogenesis, vascular barrier function, unfavorable inflammatory responses, and tissue fibrosis. In addition, experimental models of corneal neovascularization, diabetic retinopathy, proliferative vitreoretinopathy, glaucoma, or corneal injury suggest that aberrant TGF-β signaling may contribute to the pathological features of these conditions, showing the potential of modulating TGF-β signaling to treat eye diseases. This review highlights the key roles of TGF-β family members in ocular physiology and in eye diseases, and reviews approaches targeting the TGF-β signaling as potential treatment options.

Remodeling of the Lamina Cribrosa: Mechanisms and Potential Therapeutic Approaches for Glaucoma

Glaucomatous optic neuropathy is the leading cause of irreversible blindness in the world. The chronic disease is characterized by optic nerve degeneration and vision field loss. The reduction of intraocular pressure remains the only proven glaucoma treatment, but it does not prevent further neurodegeneration. There are three major classes of cells in the human optic nerve head (ONH): lamina cribrosa (LC) cells, glial cells, and scleral fibroblasts. These cells provide support for the LC which is essential to maintain healthy retinal ganglion cell (RGC) axons. All these cells demonstrate responses to glaucomatous conditions through extracellular matrix remodeling. Therefore, investigations into alternative therapies that alter the characteristic remodeling response of the ONH to enhance the survival of RGC axons are prevalent. Understanding major remodeling pathways in the ONH may be key to developing targeted therapies that reduce deleterious remodeling.

Degeneration of retina-brain components and connections in glaucoma: Disease causation and treatment options for eyesight preservation

Eyesight is the most important of our sensory systems for optimal daily activities and overall survival. Patients who experience visual impairment due to elevated intraocular pressure (IOP) are often those afflicted with primary open-angle glaucoma (POAG) which slowly robs them of their vision unless treatment is administered soon after diagnosis. The hallmark features of POAG and other forms of glaucoma are damaged optic nerve, retinal ganglion cell (RGC) loss and atrophied RGC axons connecting to various brain regions associated with receipt of visual input from the eyes and eventual decoding and perception of images in the visual cortex. Even though increased IOP is the major risk factor for POAG, the disease is caused by many injurious chemicals and events that progress slowly within all components of the eye-brain visual axis. Lowering of IOP mitigates the damage to some extent with existing drugs, surgical and device implantation therapeutic interventions. However, since multifactorial degenerative processes occur during aging and with glaucomatous optic neuropathy, different forms of neuroprotective, nutraceutical and electroceutical regenerative and revitalizing agents and processes are being considered to combat these eye-brain disorders. These aspects form the basis of this short review article.

Potential Therapeutics Targeting Upstream Regulators and Interactors of EHMT1/2

Simple Summary

The expression of Euchromatin histone lysine methyltransferase 1 and 2 (EHMT1/2) is deregulated in many cancers. Most studies thus far have focused on the downstream targets and pathways regulated by EHMTs. However, the mechanisms that lead to their deregulated expression, and the interacting proteins that could impact EHMT activity are not well understood. In this review, we summarize our current understanding of the upstream regulators and the interactors that provide alternative therapeutic approaches to tackle EHMT driven malignancies.

Abstract

Euchromatin histone lysine methyltransferases (EHMTs) are epigenetic regulators responsible for silencing gene transcription by catalyzing H3K9 dimethylation. Dysregulation of EHMT1/2 has been reported in multiple cancers and is associated with poor clinical outcomes. Although substantial insights have been gleaned into the downstream targets and pathways regulated by EHMT1/2, few studies have uncovered mechanisms responsible for their dysregulated expression. Moreover, EHMT1/2 interacting partners, which can influence their function and, therefore, the expression of target genes, have not been extensively explored. As none of the currently available EHMT inhibitors have made it past clinical trials, understanding upstream regulators and EHMT protein complexes may provide unique insights into novel therapeutic avenues in EHMT-overexpressing cancers. Here, we review our current understanding of the regulators and interacting partners of EHMTs. We also discuss available therapeutic drugs that target the upstream regulators and binding partners of EHMTs and could potentially modulate EHMT function in cancer progression.

Reintervention rate in glaucoma filtering surgery: A systematic review and meta-analysis

PURPOSE

Reintervention rate is an important factor impacting on patients, surgeons, and society. To date, only a few studies have focused on this topic. For this reason, a systematic review and meta-analysis was undertaken to assess the reintervention rate after glaucoma filtering surgery.

MATERIALS AND METHODS

Prospective studies reporting the reintervention rate after glaucoma filtering surgery and with at least 12 months of follow-up were systematically searched on PubMed, Medline and Embase databases. The primary outcome was the total reintervention rate following surgery. Secondary outcomes were: the rate of manipulation, in-clinic and in-operating room reintervention; the reintervention rate for intraocular pressure (IOP) control and for complications; demographic, clinical and surgical variables associated with reintervention rate.

RESULTS

Ninety-three studies with a total of 8345 eyes were eligible. The total reintervention rate was 1.84 (95% CI 1.57-2.13), with a lower rate for Baerveldt (0.53, 95% CI 0.29-0.83) and Preserflo (0.60, 95% CI 0.15-1.29), and a higher rate for Xen (4.26, 95% CI 2.59-6.31). The manipulation rate was 0.99 (95% CI 0.77-1.23), the in-clinic reintervention rate was 0.08 (95% CI 0.05-0.12) and the in-operating room reintervention rate was 0.28 (95% CI 0.22-0.35). The reintervention rate for IOP control was 1.26 (95% CI 1.04-1.51) and the reintervention rate for complications was 0.27 (95% CI 0.21-0.35).

CONCLUSIONS

All types of surgery presented a total reintervention rate similar to the overall findings, except studies on Baerveldt and Preserflo Microshunt, with a lower rate, and Xen, with a higher rate. None of the variables evaluated were found to be directly associated with the explored outcomes.

Emerging Evidence of Noncoding RNAs in Bleb Scarring after Glaucoma Filtration Surgery

Purpose: To conduct a narrative review of research articles on the potential anti- and pro-fibrotic mechanisms of noncoding RNAs following glaucoma filtration surgery. Methods: Keyword searches of PubMed, and Medline databases were conducted for articles discussing post-glaucoma filtration surgeries and noncoding RNA. Additional manual searches of reference lists of primary articles were performed. Results: Fifteen primary research articles were identified. Four of the included papers used microarrays and qRT-PCR to identify up- or down-regulated microRNA (miRNA, miR) profiles and direct further study, with the remainder focusing on miRNAs or long noncoding RNAs (lncRNAs) based on previous work in other organs or disease processes. The results of the reviewed papers identified miR-26a, -29b, -139, -155, and -200a as having anti-fibrotic effects. In contrast, miRs-200b and -216b may play pro-fibrotic roles in filtration surgery fibrosis. lncRNAs including H19, NR003923, and 00028 have demonstrated pro-fibrotic effects. Conclusions: Noncoding RNAs including miRNAs and lncRNAs are emerging and promising therapeutic targets in the prevention of post-glaucoma filtration surgery fibrosis.

Antisense RNA Therapeutics: A Brief Overview

Nucleic acid therapeutics is a growing field aiming to treat human conditions that has gained special attention due to the successful development of mRNA vaccines against SARS-CoV-2. Another type of nucleic acid therapeutics is antisense oligonucleotides, versatile tools that can be used in multiple ways to target pre-mRNA and mRNA. While some years ago these molecules were just considered a useful research tool and a curiosity in the clinical market, this has rapidly changed. These molecules are promising strategies for personalized treatments for rare genetic diseases and they are in development for very common disorders too. In this chapter, we provide a brief description of the different mechanisms of action of these RNA therapeutic molecules, with clear examples at preclinical and clinical stages.

Allele-Selective Locked Nucleic Acid Gapmers for the Treatment of Fibrodysplasia Ossificans Progressiva Knock Down the Pathogenic ACVR1R206H Transcript and Inhibit Osteogenic Differentiation

Fibrodysplasia ossificans progressiva (FOP) is a rare autosomal dominant disorder characterized by episodic heterotopic ossification. The median life span of people with this disorder is ∼40 years, and currently, there is no effective treatment available. More than 95% of cases are caused by a recurrent mutation (c.617G>A; R206H) of Activin A receptor, type I (ACVR1)/Activin receptor-like kinase-2 (ALK2), a bone morphogenetic protein type I receptor. The mutation renders ACVR1 responsive to activin A, which does not activate wild-type ACVR1. Ectopic activation of ACVR1^R206H by activin A induces heterotopic ossification. Since ACVR1^R206H is a hyperactive receptor, a promising therapeutic strategy is to decrease the activity of mutated ACVR1. To accomplish this goal, we developed locked nucleic acid (LNA) gapmers. These are short DNA oligonucleotides with LNA modification at both ends. They induce targeted mRNA degradation and specific knockdown of gene expression. We demonstrated that some of these gapmers efficiently knocked down ACVR1^R206H expression at RNA levels, while ACVR1^WT was mostly unaffected in human FOP fibroblasts. Also, the gapmers suppressed osteogenic differentiation induced by ACVR1^R206H and activin A. These gapmers may be promising drug candidates for FOP. This novel strategy will also pave the way for antisense-mediated therapy of other autosomal dominant disorders.

Oligonucleotide Therapeutics: From Discovery and Development to Patentability

Following the first proof of concept of using small nucleic acids to modulate gene expression, a long period of maturation led, at the end of the last century, to the first marketing authorization of an oligonucleotide-based therapy. Since then, 12 more compounds have hit the market and many more are in late clinical development. Many companies were founded to exploit their therapeutic potential and Big Pharma was quickly convinced that oligonucleotides could represent credible alternatives to protein-targeting products. Many technologies have been developed to improve oligonucleotide pharmacokinetics and pharmacodynamics. Initially targeting rare diseases and niche markets, oligonucleotides are now able to benefit large patient populations. However, there is still room for oligonucleotide improvement and further breakthroughs are likely to emerge in the coming years. In this review we provide an overview of therapeutic oligonucleotides. We present in particular the different types of oligonucleotides and their modes of action, the tissues they target and the routes by which they are administered to patients, and the therapeutic areas in which they are used. In addition, we present the different ways of patenting oligonucleotides. We finally discuss future challenges and opportunities for this drug-discovery platform.

Reduction of Off-Target Effects of Gapmer Antisense Oligonucleotides by Oligonucleotide Extension

Aim

Antisense oligonucleotide (ASO) has the potential to induce off-target effects by inadvertent binding of ASOs to unintended RNAs that have a sequence similar to the target RNA. In the present study, we focused on the association between oligonucleotide length and off-target effects. Oligonucleotide extension is assumed to have bilateral effects on hybridization-dependent changes in gene expression, i.e., one is the decrease of off-target effects based on the reduced number of off-target candidate genes with perfect matches, and the other is the increase of off-target effects based on the increased binding affinity between the ASO and the complementary RNAs that leads to better tolerability for mismatches.

Methods

To determine the effects of oligonucleotide extension of gapmer ASOs on off-target effects, an extensive microarray analysis was performed using human cells treated with a 14-mer gapmer ASO and the extended 18-mer derivatives with the same core 14-mer region.

Results and Discussion

Our data indicated that change in gene expression in the cells treated with 18-mer ASOs was significantly smaller than those with a 14-mer ASO, showing the decrease of off-target effects by oligonucleotide extension.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40291-021-00573-z.

Overcoming TGFβ-mediated immune evasion in cancer

Transforming growth factor-β (TGFβ) signalling controls multiple cell fate decisions during development and tissue homeostasis; hence, dysregulation of this pathway can drive several diseases, including cancer. Here we discuss the influence that TGFβ exerts on the composition and behaviour of different cell populations present in the tumour immune microenvironment, and the context-dependent functions of this cytokine in suppressing or promoting cancer. During homeostasis, TGFβ controls inflammatory responses triggered by exposure to the outside milieu in barrier tissues. Lack of TGFβ exacerbates inflammation, leading to tissue damage and cellular transformation. In contrast, as tumours progress, they leverage TGFβ to drive an unrestrained wound-healing programme in cancer-associated fibroblasts, as well as to suppress the adaptive immune system and the innate immune system. In consonance with this key role in reprogramming the tumour microenvironment, emerging data demonstrate that TGFβ-inhibitory therapies can restore cancer immunity. Indeed, this approach can synergize with other immunotherapies - including immune checkpoint blockade - to unleash robust antitumour immune responses in preclinical cancer models. Despite initial challenges in clinical translation, these findings have sparked the development of multiple therapeutic strategies that inhibit the TGFβ pathway, many of which are currently in clinical evaluation.

The Effect of CHIR 99021, a Glycogen Synthase Kinase-3β Inhibitor, on Transforming Growth Factor β-Induced Tenon Fibrosis

Purpose

This study investigated the effect of glycogen synthase kinase-3β (GSK-3β) inhibition on the fibrosis of human Tenon's fibroblasts (HTFs) induced by transforming growth factor-β (TGF-β).

Methods

Quantitative real-time PCR and Western blot analyses were performed to determine the expression levels of molecules associated with the fibrosis of HTFs by TGF-β (fibronectin, collagen Iα, and α-smooth muscle actin) and GSK-3β. The levels of phosphorylated Smad2 and Smad3 were also analyzed in the presence of the GSK-3β inhibitor CHIR 99021. The wound healing assay was performed to determine the effect of CHIR 99021 on the migration of HTFs. All experiments were conducted using primary cultured HTFs or human tenon tissues obtained from normal subjects and patients with glaucoma.

Results

Treatment with TGF-β resulted in an increase in the levels of molecules associated with the fibrosis of HTFs. The expression levels of these molecules were higher in the tenon tissues obtained from patients with glaucoma than those from normal subjects. When the HTFs were treated with TGF-β, a significant increase in the active form of GSK-3β (Y216) was observed. A significant decrease in the active form of GSK-3β and molecules associated with fibrosis by TGF-β was noted in HTFs treated with CHIR 99021. CHIR 99021 treatment reduced the phosphorylated Smad2/Smad2 and phosphorylated Smad3/Smad3 ratios in HTFs and attenuated HTF migration.

Conclusions

Our results demonstrated the effect of GSK-3β inhibition on the regulation of TGF-β–mediated fibrosis of HTFs, suggesting GSK-3β to be a potential target for maintaining bleb function after glaucoma filtration surgery.

TGF-β-induced fibrosis: A review on the underlying mechanism and potential therapeutic strategies

Transforming growth factor-beta (TGF-β) plays multiple homeostatic roles in the regulation of inflammation, proliferation, differentiation and would healing of various tissues. Many studies have demonstrated that TGF-β stimulates activation and proliferation of fibroblasts, which result in extracellular matrix deposition. Its increased expression can result in many fibrotic diseases, and the level of expression is often correlated with disease severity. On this basis, inhibition of TGF-β and its activity has great therapeutic potential for the treatment of various fibrotic diseases such as pulmonary fibrosis, renal fibrosis, systemic sclerosis and etc. By understanding the molecular mechanism of TGF-β signaling and activity, researchers were able to develop different strategies in order to modulate the activity of TGF-β. Antisense oligonucleotide was developed to target the mRNA of TGF-β to inhibit its expression. There are also neutralizing monoclonal antibodies that can target the TGF-β ligands or α_vβ₆ integrin to prevent binding to receptor or activation of latent TGF-β respectively. Soluble TGF-β receptors act as ligand traps that competitively bind to the TGF-β ligands. Many small molecule inhibitors have been developed to inhibit the TGF-β receptor at its cytoplasmic domain and also intracellular signaling molecules. Peptide aptamer technology has been used to target downstream TGF-β signaling. Here, we summarize the underlying mechanism of TGF-β-induced fibrosis and also review various strategies of inhibiting TGF-β in both preclinical and clinical studies.

Therapeutic Drugs and Devices for Tackling Ocular Hypertension and Glaucoma, and Need for Neuroprotection and Cytoprotective Therapies

Damage to the optic nerve and the death of associated retinal ganglion cells (RGCs) by elevated intraocular pressure (IOP), also known as glaucoma, is responsible for visual impairment and blindness in millions of people worldwide. The ocular hypertension (OHT) and the deleterious mechanical forces it exerts at the back of the eye, at the level of the optic nerve head/optic disc and lamina cribosa, is the only modifiable risk factor associated with glaucoma that can be treated. The elevated IOP occurs due to the inability of accumulated aqueous humor (AQH) to egress from the anterior chamber of the eye due to occlusion of the major outflow pathway, the trabecular meshwork (TM) and Schlemm’s canal (SC). Several different classes of pharmaceutical agents, surgical techniques and implantable devices have been developed to lower and control IOP. First-line drugs to promote AQH outflow via the uveoscleral outflow pathway include FP-receptor prostaglandin (PG) agonists (e.g., latanoprost, travoprost and tafluprost) and a novel non-PG EP2-receptor agonist (omidenepag isopropyl, Eybelis^®). TM/SC outflow enhancing drugs are also effective ocular hypotensive agents (e.g., rho kinase inhibitors like ripasudil and netarsudil; and latanoprostene bunod, a conjugate of a nitric oxide donor and latanoprost). One of the most effective anterior chamber AQH microshunt devices is the Preserflo^® microshunt which can lower IOP down to 10–13 mmHg. Other IOP-lowering drugs and devices on the horizon will be also discussed. Additionally, since elevated IOP is only one of many risk factors for development of glaucomatous optic neuropathy, a treatise of the role of inflammatory neurodegeneration of the optic nerve and retinal ganglion cells and appropriate neuroprotective strategies to mitigate this disease will also be reviewed and discussed.

From bench side to clinic: Potential and challenges of RNA vaccines and therapeutics in infectious diseases

The functional and structural versatility of Ribonucleic acids (RNAs) makes them ideal candidates for overcoming the limitations imposed by small molecule-based drugs. Hence, RNA-based biopharmaceuticals such as messenger RNA (mRNA) vaccines, antisense oligonucleotides (ASOs), small interfering RNAs (siRNAs), microRNA mimics, anti-miRNA oligonucleotides (AMOs), aptamers, riboswitches, and CRISPR-Cas9 are emerging as vital tools for the treatment and prophylaxis of many infectious diseases. Some of the major challenges to overcome in the area of RNA-based therapeutics have been the instability of single-stranded RNAs, delivery to the diseased cell, and immunogenicity. However, recent advancements in the delivery systems of in vitro transcribed mRNA and chemical modifications for protection against nucleases and reducing the toxicity of RNA have facilitated the entry of several exogenous RNAs into clinical trials. In this review, we provide an overview of RNA-based vaccines and therapeutics, their production, delivery, current advancements, and future translational potential in treating infectious diseases.

Is the Conjunctiva a Potential Target for Advanced Therapy Medicinal Products?

The conjunctiva is a complex ocular tissue that provides mechanical, sensory, and immune protection for the ocular surface. It is affected by many diseases through different pathological mechanisms. If a disease is not treated and conjunctival function is not fully restored, the whole ocular surface and, therefore, sight is at risk. Different therapeutic approaches have been proposed, but there are still unsolved conjunctival alterations that require more sophisticated therapeutic options. Advanced therapy medicinal products (ATMPs) comprise a wide range of products that includes cell therapy, tissue engineering, and gene therapy. To the best of our knowledge, there is no commercialized ATMP specifically for conjunctival treatment yet. However, the conjunctiva can be a potential target for ATMPs for different reasons. In this review, we provide an overview of the advances in experimental phases of potential ATMPs that primarily target the conjunctiva. Important advances have been achieved through the techniques of cell therapy and tissue engineering, whereas the use of gene therapy in the conjunctiva is still marginal. Undoubtedly, future research in this field will lead to achieving commercially available ATMPs for the conjunctiva, which may provide better treatments for patients.

Antisense Oligonucleotide Therapy for Ophthalmic Conditions

Antisense oligonucleotides (AON) are synthetic single-stranded fragments of nucleic acids that bind to a specific complementary messenger RNA (mRNA) sequence and change the final gene product. AON were initially approved for treating cytomegalovirus retinitis and have shown promise in treating Mendelian systemic disease. AON are currently being investigated as a treatment modality for many ophthalmic diseases, including inherited retinal disorders (IRD), inflammatory response and wound healing after glaucoma surgery, and macular degeneration. They provide a possible solution to gene therapy for IRD that are not candidates for adeno-associated virus (AAV) delivery. This chapter outlines the historical background of AON and reviews clinical applications and ongoing clinical trials.

Antisense technology: an overview and prospectus

Antisense technology is now beginning to deliver on its promise to treat diseases by targeting RNA. Nine single-stranded antisense oligonucleotide (ASO) drugs representing four chemical classes, two mechanisms of action and four routes of administration have been approved for commercial use, including the first RNA-targeted drug to be a major commercial success, nusinersen. Although all the approved drugs are for use in patients with rare diseases, many of the ASOs in late- and middle-stage clinical development are intended to treat patients with very common diseases. ASOs in development are showing substantial improvements in potency and performance based on advances in medicinal chemistry, understanding of molecular mechanisms and targeted delivery. Moreover, the ASOs in development include additional mechanisms of action and routes of administration such as aerosol and oral formulations. Here, we describe the key technological advances that have enabled this progress and discuss recent clinical trials that illustrate the impact of these advances on the performance of ASOs in a wide range of therapeutic applications. We also consider strategic issues such as target selection and provide perspectives on the future of the field.

Looking into the future: Gene and cell therapies for glaucoma

Glaucoma is a complex group of optic neuropathies that affects both humans and animals. Intraocular pressure (IOP) elevation is a major risk factor that results in the loss of retinal ganglion cells (RGCs) and their axons. Currently, lowering IOP by medical and surgical methods is the only approved treatment for primary glaucoma, but there is no cure, and vision loss often progresses despite therapy. Recent technologic advances provide us with a better understanding of disease mechanisms and risk factors; this will permit earlier diagnosis of glaucoma and initiation of therapy sooner and more effectively. Gene and cell therapies are well suited to target these mechanisms specifically with the potential to achieve a lasting therapeutic effect. Much progress has been made in laboratory settings to develop these novel therapies for the eye. Gene and cell therapies have already been translated into clinical application for some inherited retinal dystrophies and age-related macular degeneration (AMD). Except for the intravitreal application of ciliary neurotrophic factor (CNTF) by encapsulated cell technology for RGC neuroprotection, there has been no other clinical translation of gene and cell therapies for glaucoma so far. Possible application of gene and cell therapies consists of long-term IOP control via increased aqueous humor drainage, including inhibition of fibrosis following filtration surgery, RGC neuroprotection and neuroregeneration, modification of ocular biomechanics for improved IOP tolerance, and inhibition of inflammation and neovascularization to prevent the development of some forms of secondary glaucoma.

RNA therapeutics in ophthalmology - translation to clinical trials

The use of RNA interference technology has proven to inhibit the expression of many target genes involved in the underlying pathogenesis of several diseases affecting various systems. First established in in vitro and later in animal studies, small interfering RNA (siRNA) and antisense oligonucleotide (ASO) therapeutics are now entering clinical trials with the potential of clinical translation to patients. Gene-silencing therapies have demonstrated promising responses in ocular disorders, predominantly due to the structure of the eye being a closed and compartmentalised organ. However, although the efficacy of such treatments has been observed in both preclinical studies and clinical trials, there are issues pertaining to the use of these drugs which require more extensive research with regards to the delivery and stability of siRNAs and ASOs. This would improve their use for long-term treatment regimens and alleviate the difficulties experienced by patients with ocular diseases. This review provides a detailed insight into the recent developments and clinical trials that have been conducted for several gene-silencing therapies, including ISTH0036, SYL040012, SYL1001, PF-04523655, Sirna-027, QR-110, QR-1123, QR-421a and IONIS-FB-L_RX in glaucoma, dry eye disease, age-related macular degeneration, diabetic macular oedema and various inherited retinal diseases. Our aim is to explore the potential of these drugs whilst evaluating their associated advantages and disadvantages, and to discuss the future translation of RNA therapeutics in ophthalmology.

Antisense technology: A review

Antisense technology is beginning to deliver on the broad promise of the technology. Ten RNA-targeted drugs including eight single-strand antisense drugs (ASOs) and two double-strand ASOs (siRNAs) have now been approved for commercial use, and the ASOs in phase 2/3 trials are innovative, delivered by multiple routes of administration and focused on both rare and common diseases. In fact, two ASOs are used in cardiovascular outcome studies and several others in very large trials. Interest in the technology continues to grow, and the field has been subject to a significant number of reviews. In this review, we focus on the molecular events that result in the effects observed and use recent clinical results involving several different ASOs to exemplify specific molecular mechanisms and specific issues. We conclude with the prospective on the technology.

Novel Drug Delivery Systems Fighting Glaucoma: Formulation Obstacles and Solutions

Glaucoma is considered to be one of the biggest health problems in the world. It is the main cause of preventable blindness due to its asymptomatic nature in the early stages on the one hand and patients' non-adherence on the other. There are several approaches in glaucoma treatment, whereby this has to be individually designed for each patient. The first-line treatment is medication therapy. However, taking into account numerous disadvantages of conventional ophthalmic dosage forms, intensive work has been carried out on the development of novel drug delivery systems for glaucoma. This review aims to provide an overview of formulation solutions and strategies in the development of in situ gel systems, nanosystems, ocular inserts, contact lenses, collagen corneal shields, ocular implants, microneedles, and iontophoretic devices. The results of studies confirming the effectiveness of the aforementioned drug delivery systems were also briefly presented.

Recent progress in TGF-β inhibitors for cancer therapy

Transforming growth factor-β (TGF-β) is a multifunctional cytokine that is involved in proliferation, metastasis, and many other important processes in malignancy. Inhibitors targeting TGF-β have been considered by pharmaceutical companies for cancer therapy, and some of them are in clinical trial now. Unfortunately, several of these programs have recently been relinquished, and most companies that remain in the contest are progressing slowly and cautiously. This review summarizes the TGF-β signal transduction pathway, its roles in oncogenesis and fibrotic diseases, and advancements in antibodies and small-molecule inhibitors of TGF-β.

Antisense drug discovery and development technology considered in a pharmacological context

When coined, the term "antisense" included oligonucleotides of any structure, with any chemical modification and designed to work through any post-RNA hybridization mechanism. However, in practice the term "antisense" has been used to describe single stranded oligonucleotides (ss ASOs) designed to hybridize to RNAswhile the term "siRNA" has come to mean double stranded oligonucleotides designed to activate Ago2. However, the two approaches share many common features. The medicinal chemistry developed for ASOs greatly facilitated the development of siRNA technology and remains the chemical basis for both approaches. Many of challenges faced and solutions achieved share many common features. In fact, because ss ASOs can be designed to activate Ago2, the two approaches intersect at this remarkably important protein. There are also meaningful differences. The pharmacokinetic properties are quite different and thus potential routes of delivery differ. ASOs may be designedto use a variety of post-RNA binding mechanismswhile siRNAs depend solely on the robust activity of Ago2. However, siRNAs and ASOs are both used for therapeutic purposes and both must be and can be understood in a pharmacological context. Thus, the goals of this review are to put ASOs in pharmacological context and compare their behavior as pharmacological agents to the those of siRNAs.

Corneal thinning and cornea guttata in patients with mutations in TGFB2

OBJECTIVE

Human genome-wide association studies and animal models suggest a role for TGFB2 in contributing to the corneal thickness phenotype. No specific mutations, however, have been reported in this gene that affect corneal thickness. We sought to determine if haploinsufficiency of TGFB2 in humans associated with Loeys-Dietz syndrome type 4 is associated with corneal thinning.

DESIGN

Observational cohort study of families with Loeys-Dietz syndrome type 4, caused specifically by TGFB2 mutations, in a tertiary care setting.

PARTICIPANTS

Three probands with pathogenic mutations in TGFB2 and family members underwent comprehensive ophthalmic examination.

METHODS

Clinical assessment included Scheimpflug imaging, specular microscopy, and slit-lamp biomicroscopy. We measured visual acuity, axial length, refractive error, and central corneal thickness.

RESULTS

Clinical evaluation of 2 probands identified corneal thinning and cornea guttata, despite a young age and distinct mutations in TGFB2 (c.905G>A, p.Arg302His; c.988C>A, p.Arg330Ser). In the third family, corneal thinning co-segregated with a TGFB2 mutation (c.1103G>A, p.Gly368Glu), although without apparent guttae.

CONCLUSIONS

In this series, participants with TGFB2 mutations associated with Loeys-Dietz syndrome type 4 demonstrated decreased corneal thickness, and in 2 cases with splice site mutations, also demonstrated cornea guttata. The data demonstrate the importance of considering distinct phenotype-genotype correlations within this condition.

Lowered Decorin With Aberrant Extracellular Matrix Remodeling in Aqueous Humor and Tenon's Tissue From Primary Glaucoma Patients

Purpose

To evaluate the inflammatory cytokine, growth factors, extracellular matrix (ECM) remodeling genes, profibrotic and antifibrotic molecules in patients undergoing glaucoma filtration surgery (GFS). Additionally, the effect of preoperative antiglaucoma medications (AGMs) and postoperative bleb status were related to these parameters.

Methods

Tenon's tissue and aqueous humour (AH) were collected from 207 patients undergoing GFS with primary open-angle glaucoma (POAG) (n = 77), primary angle-closure glaucoma (PACG) (n = 62), and cataract controls (n = 68). Monocyte chemoattractant protein-1 (MCP-1), connective tissue growth factor (CTGF), transforming growth factor β1/2 (TGF-β1/2), lysyl oxidase (LOX), lysyl oxidase L2 (LOXL2), elastin (ELN), collagen type 1 α 1 (COL1A1), secreted protein acidic and rich in cysteine (SPARC), α-smooth muscle actin (α-SMA), and decorin (DCN) were determined in tenon's tissue by real-time PCR and in AH using ELISA.

Results

A significant increase was observed in the transcripts of MCP-1, TGF-β2, and SPARC in POAG and PACG (P < 0.05); CTGF, TGF-β1, LOX, LOXL2, ELN, COL1A1, and α-SMA in PACG (P < 0.05) compared with control. DCN transcript was significantly decreased in POAG and PACG (P < 0.05) compared with control. The protein levels of CTGF, TGF-β1/β2, ELN, SPARC, and LOXL2 was significantly elevated in POAG and PACG (P < 0.05); DCN was decreased (P < 0.05) compared with control. These parameters showed significant association with duration of preoperative AGMs and postoperative bleb status.

Conclusions

This study demonstrates increased expression of growth factors and ECM molecules, both at protein and transcript levels in GFS patients. A decreased DCN in AH seems striking, and if restored might have a therapeutic role in minimizing postoperative scarring to improve GFS outcome.

Cross-talk between MYOC p. Y437H mutation and TGF-β2 in the pathology of glaucoma

Objective: To identify the interaction between the MYOC Y437H mutation and TGF-β2 in a family with primary open-angle glaucoma (POAG). Methods: The MYOC Y437H mutation was identified in a family with POAG; the family was a fourth-generation family with 27 members, of which 6 members were affected. Analysis focused on the secreted myocilin protein and TGF-β2 found in the aqueous humor. Samples were taken both from normal controls and MYOC mutant carriers and cross-talk between MYOC Y437H and TGF-β2 were evaluated in the trabecular meshwork (TM) cells. Results: Aqueous humor secreted myocilin protein levels were reduced while TGF-β2 levels were increased in patients with the MYOC (c.1309T>C) mutation. This inverse relationship indicated that elevated TGF-β2 may be an important pathogenic mechanism in the progression of myocilin-related POAG. In TM cells expressing the MYOC Y437H mutant, exogenous TGF-β2 also significantly increased myocilin expression as well as the endoplasmic reticulum (ER) stress markers GRP94 and CHOP. This increase in TGF-β2 was also associated with increased cell death in cells carrying the MYOC Y437H mutation. Conclusion: These data collectively suggest that the mutual interaction between glaucomatous MYOC mutation and TGF-β2 contributed to the cell death of TM cells. This relationship also provides a new, therapeutic targets for the treatment of glaucoma.

RNA Therapeutics: How Far Have We Gone?

In recent years, the RNA molecule became one of the most promising targets for therapeutic intervention. Currently, a large number of RNA-based therapeutics are being investigated both at the basic research level and in late-stage clinical trials. Some of them are even already approved for treatment. RNA-based approaches can act at pre-mRNA level (by splicing modulation/correction using antisense oligonucleotides or U1snRNA vectors), at mRNA level (inhibiting gene expression by siRNAs and antisense oligonucleotides) or at DNA level (by editing mutated sequences through the use of CRISPR/Cas). Other RNA approaches include the delivery of in vitro transcribed (IVT) mRNA or the use of oligonucleotides aptamers. Here we review these approaches and their translation into clinics trying to give a brief overview also on the difficulties to its application as well as the research that is being done to overcome them.

Mapping mRNA Expression of Glaucoma Genes in the Healthy Mouse Eye

Purpose/Aim: Many genes have been associated with primary open-angle glaucoma (POAG). Knowing exactly where they are expressed in the eye helps to unravel POAG pathology and to select optimal targets for intervention. We investigated whether RNA in situ hybridization (RNA-ISH) is a convenient technique to obtain detailed pan-ocular expression data of these genes. We tested this for four diverse candidate POAG genes, selected because of unclear ocular distribution (F5 and Dusp1) and relevance for potential new therapies (Tnf, Tgfβr3). Optn, a POAG gene with well-known ocular expression pattern served as control. Methods: We made a list of candidate glaucoma genes reported in genetic studies. A table of their ocular expression at the tissue level was compiled using publicly available microarray data (the ocular tissue database). To add cellular detail we performed RNA-ISH for Optn, Tnf, Tgfβr3, F5, and Dusp1 on eyes of healthy, 2-month-old, pigmented, and albino mice. Results: Expression of the Optn control matched with published immunohistochemistry data. Ocular expression of Tnf was generally low, with patches of higher Tnf expression, superficially in the corneal epithelium. F5 had a restricted expression pattern with high expression in the nonpigmented ciliary body epithelium and moderate expression in the peripapillary region. Tgfβr3 and Dusp1 showed ubiquitous expression. Conclusions: RNA-ISH is a suitable technique to determine the ocular expression pattern of POAG genes, adding meaningful cellular detail to existing microarray expression data. For instance, the high expression of F5 in the nonpigmented ciliary body epithelium suggests a role of this gene in aqueous humor dynamics and intraocular pressure. In addition, the ubiquitous expression of Tgfβr3 has implications for designing TGF-β-related glaucoma therapies, with respect to side effects. Creating pan-ocular expression maps of POAG genes with RNA-ISH will help to identify POAG pathways in specific cell types and to select targets for drug development.

Causative glaucoma treatment: promising targets and delivery systems

Glaucoma is one of the most common causes of blindness worldwide. Elevated intraocular pressure (IOP) is the major modifiable risk factor of the disease. Conventional therapy suffers from poor compliance, low bioavailability, and the lack of causative treatment options. To improve therapeutic success, it is crucial to identify major mediators of pathological changes associated with elevated IOP and to intervene at the molecular level. Here, we discuss relevant key functions of transforming growth factor-β2 (TGF-β2), connective tissue growth factor (CTGF), integrins, Rho-associated kinase (ROCK), and nitric oxide (NO) with regard to the onset of glaucoma, highlighting new drug delivery approaches for causative treatment.

Inhibitory role of transforming growth factor β2 in experimental autoimmune anterior uveitis

PURPOSE

Experimental autoimmune anterior uveitis (EAAU) is a clinically relevant animal model for human idiopathic anterior uveitis (IAU). The role of the immunomodulator transforming growth factor β2 (TGF-β2) in EAAU pathology is unknown. In this study, we investigated the regulatory role of TGF-β2 in EAAU.

METHODS

EAAU was induced in male Lewis rats by footpad injection of melanin-associated antigen (MAA). TGF-β2 was administered intravenously (iv) in MAA-sensitized rats during the induction of EAAU, or after the clinical onset of uveitis. MAA-sensitized rats injected similarly with an equal volume of PBS served as control. Animals were examined daily between days 7 and 30 post-injection for the clinical signs of uveitis using slit lamp biomicroscopy. Animals were sacrificed at various time points and eyes were harvested for histological analysis to assess the course and severity of inflammation. For histopathological analysis, paraffin sections of harvested eyes were stained with hematoxylin and eosin. Popliteal lymph nodes (LNs) were used for CD4⁺CD25⁺FoxP3⁺ T regulatory (Tregs) population analysis and for CD4⁺ T cell proliferation assay.

RESULTS

Administration of recombinant TGF-β2 during the early stages of EAAU prevented the induction of uveitis. Compared to PBS, the presence of TGF-β2 in the cell culture significantly (p < 0.05) inhibited the proliferation of CD4⁺ T cells in response to MAA. In MAA-sensitized Lewis rats, iv treatment with recombinant TGF-β2 resulted in significantly (p < 0.05) increased percentage of Tregs compared to animals treated similarly with PBS. Thus, TGF-β2 inhibited the induction of EAAU by inhibiting CD4⁺ T cell proliferation and increasing the number of Tregs. Injection of TGF-β2 in rats with active EAAU resulted in diminished disease activity. Unfortunately, this treatment did not lead to the early resolution of EAAU.

CONCLUSIONS

TGF-β2 plays a critical role in regulation of intraocular inflammation in EAAU. Findings reported in this study improve our understanding of immunopathology of IAU and suggest that recombinant TGF-β2 may be a promising therapeutic agent for human IAU.

Glaucoma - Next Generation Therapeutics: Impossible to Possible

The future of next generation therapeutics for glaucoma is strong. The recent approval of two novel intraocular pressure (IOP)-lowering drugs with distinct mechanisms of action is the first in over 20 years. However, these are still being administered as topical drops. Efforts are underway to increase patient compliance and greater therapeutic benefits with the development of sustained delivery technologies. Furthermore, innovations from biologics- and gene therapy-based therapeutics are being developed in the context of disease modification, which are expected to lead to more permanent therapies for patients. Neuroprotection, including the preservation of retinal ganglion cells (RGCs) and optic nerve is another area that is actively being explored for therapeutic options. With improvements in imaging technologies and determination of new surrogate clinical endpoints, the therapeutic potential for translation of neuroprotectants is coming close to clinical realization. This review summarizes the aforementioned topics and other related aspects.