Genetic Risk, Inflammation, and Therapeutics: An Editorial Overview of Recent Advances in Aging Brains and Neurodegeneration.

Neurodegenerative disorders, including Dementia, Parkinson's disease, various Vision disorders, Multiple sclerosis, and transsynaptic degenerative changes represent a significant challenge in aging populations. This editorial synthesizes and discusses recent advancements in understanding the genetic and environmental factors contributing to these diseases. Central to these advancements is the role of neuroinflammation and oxidative stress, which exacerbate neuronal damage and accelerate disease progression. Emerging research underscores the significance of mitochondrial dysfunction and protein aggregation in neurodegenerative pathology, highlighting shared mechanisms across various disorders. Innovative therapeutic strategies, including gene therapy, CRISPR-Cas technology, and the use of naturally occurring antioxidant molecules, are being investigated to target and manage these conditions. Additionally, lifestyle interventions such as exercise and healthy diet have shown promise in enhancing brain plasticity and reducing neuroinflammation. Advances in neuroimaging and biomarker discovery are necessary to improve early diagnosis, while clinical and preclinical studies are essential for the translation of these novel treatments. This edition aims to bridge the gap between molecular mechanisms and therapeutic applications, offering insights into potential interventions to mitigate the impact of neurodegenerative diseases. By establishing a deeper understanding of these complex processes, we aim to move closer to effective prevention and treatment strategies, ultimately improving the quality of life for those affected by neurodegenerative disorders.

RXR agonist, 9-cis-13,14-dihydroretinoic acid (9CDHRA), reduces damage and protects from demyelination in transsynaptic degeneration model.

Neurodegenerative and demyelinating disease, such as multiple sclerosis (MS) are at the forefront of medical research and the discovery of new drugs and therapeutics. One phenomenon of degeneration seen in these diseases is transsynaptic degeneration (TSD), where damage from one axon spreads to the other axons that are connected to it synaptically. It has previously been found that demyelination occurs prior to neuronal loss in an experimental form of induced TSD. Retinoid-x receptor (RXR) agonists have been shown to promote remyelination. Therefore, this study aimed to reveal the effects of a novel endogenous RXR-γ agonist, 9-cis-13,14-dihydroretinoic acid (9CDHRA), on preventing or restoring the effects of TSD. 9CDHRA was administered to mice following optic nerve crush (ONC) procedures, and electrophysiology (visual evoked potential, VEP) and histological (immunofluorescent) assessments were performed. It was found that 9CDHRA treatment effectively delayed glial activation and reduced the presence of apoptosis at the site of injury and further anterogradely in the visual system, including the lateral geniculate nucleus (LGN) and primary visual cortex (V1). Most notably, 9CDHRA was able to maintain myelin levels following ONC, and effectively protected from demyelination. This was corroborated by VEP recordings with improved P1 latency. The promising findings regarding the injury attenuating and myelin protecting properties of 9CDHRA necessitates further investigations into the potential therapeutic uses of this compound.

Neuropeptide Y receptor activation preserves inner retinal integrity through PI3K/Akt signaling in a glaucoma mouse model.

Neuropeptide Y (NPY), an endogenous peptide composed of 36 amino acids, has been investigated as a potential therapeutic agent for neurodegenerative diseases due to its neuroprotective attributes. This study investigated the neuroprotective effects of NPY in a mouse model of glaucoma characterized by elevated intraocular pressure (IOP) and progressive retinal ganglion cell degeneration. Elevated IOP in mice was induced through intracameral microbead injections, accompanied by intravitreal administration of NPY peptide. The results demonstrated that NPY treatment preserved both the structural and functional integrity of the inner retina and mitigated axonal damage and degenerative changes in the optic nerve under high IOP conditions. Further, NPY treatment effectively reduced inflammatory glial cell activation, as evidenced by decreased expression of glial fibrillary acidic protein and Iba-1. Notably, endogenous NPY expression and its receptors (NPY-Y1R and NPY-Y4R) levels were negatively affected in the retina under elevated IOP conditions. NPY treatment restored these changes to a significant extent. Molecular analysis revealed that NPY mediates its protective effects through the mitogen-activated protein kinase (MAPK) and PI3K/Akt signaling pathways. These findings highlight the therapeutic potential of NPY in glaucoma treatment, underscoring its capacity to preserve retinal health, modulate receptor expression under stress, reduce neuroinflammation, and impart protection against axonal impairment.

Mitochondrial signaling pathways and their role in cancer drug resistance.

Mitochondria, traditionally known as cellular powerhouses, now emerge as critical signaling centers influencing cancer progression and drug resistance. The review highlights the role that apoptotic signaling, DNA mutations, mitochondrial dynamics and metabolism play in the development of resistance mechanisms and the advancement of cancer. Targeted approaches are discussed, with an emphasis on managing mitophagy, fusion, and fission of the mitochondria to make resistant cancer cells more susceptible to traditional treatments. Additionally, metabolic reprogramming can be used to effectively target metabolic enzymes such GLUT1, HKII, PDK, and PKM2 in order to avoid resistance mechanisms. Although there are potential possibilities for therapy, the complex structure of mitochondria and their subtle role in tumor development hamper clinical translation. Novel targeted medicines are put forth, providing fresh insights on combating drug resistance in cancer. The study also emphasizes the significance of glutamine metabolism, mitochondrial respiratory complexes, and apoptotic pathways as potential targets to improve treatment effectiveness against drug-resistant cancers. Combining complementary and nanoparticle-based techniques to target mitochondria has demonstrated encouraging results in the treatment of cancer, opening doors to reduce resistance and enable individualized treatment plans catered to the unique characteristics of each patient. Suggesting innovative approaches such as drug repositioning and mitochondrial drug delivery to enhance the efficacy of mitochondria-targeting therapies, presenting a pathway for advancements in cancer treatment. This thorough investigation is a major step forward in the treatment of cancer and has the potential to influence clinical practice and enhance patient outcomes.

Tau modulation through AAV9 therapy augments Akt/Erk survival signalling in glaucoma mitigating the retinal degenerative phenotype.

The microtubule-associated protein Tau is a key player in various neurodegenerative conditions, including Alzheimer's disease (AD) and Tauopathies, where its hyperphosphorylation disrupts neuronal microtubular lattice stability. Glaucoma, a neurodegenerative disorder affecting the retina, leads to irreversible vision loss by damaging retinal ganglion cells and the optic nerve, often associated with increased intraocular pressure. Prior studies have indicated Tau expression and phosphorylation alterations in the retina in both AD and glaucoma, yet the causative or downstream nature of Tau protein changes in these pathologies remains unclear. This study investigates the impact of Tau protein modulation on retinal neurons under normal and experimental glaucoma conditions. Employing AAV9-mediated gene therapy for Tau overexpression and knockdown, both manipulations were found to adversely affect retinal structural and functional measures as well as neuroprotective Akt/Erk survival signalling in healthy conditions. In the experimental glaucoma model, Tau overexpression intensified inner retinal degeneration, while Tau silencing provided significant protection against these degenerative changes. These findings underscore the critical role of endogenous Tau protein levels in preserving retinal integrity and emphasize the therapeutic potential of targeting Tau in glaucoma pathology.

Brain-Derived Neurotrophic Factor Val66Met is Associated with Variation in Cortical Structure in Healthy Aging Subjects.

Aging is associated with progressive brain atrophy and declines in learning and memory, often attributed to hippocampal or cortical deterioration. The role of brain-derived neurotrophic factor (BDNF) in modulating the structural and functional changes in the brain and visual system, particularly in relation to BDNF Val66Met polymorphism, remains underexplored. In this present cross-sectional observational study, we aimed to assess the effects of BDNF polymorphism on brain structural integrity, cognitive function, and visual pathway alterations. A total of 108 older individuals with no evidence of dementia and a mean (SD) age of 67.3 (9.1) years were recruited from the Optic Nerve Decline and Cognitive Change (ONDCC) study cohort. The BDNF Met allele carriage had a significant association with lower entorhinal cortex volume (6.7% lower compared to the Val/Val genotype, P = 0.02) and posterior cingulate volume (3.2% lower than the Val/Val group, P = 0.03), after adjusting for confounding factors including age, sex and estimated total intracranial volumes (eTIV). No significant associations were identified between the BDNF Val66Met genotype and other brain volumetric or diffusion measures, cognitive performances, or vision parameters except for temporal retinal nerve fibre layer thickness. Small but significant correlations were found between visual structural and functional, cognitive, and brain morphological metrics. Our findings suggest that carriage of BDNF Val66Met polymorphism is associated with lower entorhinal cortex and posterior cingulate volumes and may be involved in modulating the cortical morphology along the aging process.

Glial Cell Activation and Immune Responses in Glaucoma: A Systematic Review of Human Postmortem Studies of the Retina and Optic Nerve.

Although researched extensively the understanding regarding mechanisms underlying glaucoma pathogenesis remains limited. Further, the exact mechanism behind neuronal death remains elusive. The role of neuroinflammation in retinal ganglion cell (RGC) death has been prominently theorised. This review provides a comprehensive summary of neuroinflammatory responses in glaucoma. A systematic search of Medline and Embase for articles published up to 8th March 2023 yielded 32 studies using post-mortem tissues from glaucoma patients. The raw data were extracted from tables and text to calculate the standardized mean differences (SMDs). These studies utilized post-mortem tissues from glaucoma patients, totalling 490 samples, compared with 380 control samples. Among the included studies, 27 reported glial cell activation based on changes to cellular morphology and molecular staining. Molecular changes were predominantly attributed to astrocytes (62.5%) and microglia (15.6%), with some involvement of Muller cells. These glial cell changes included amoeboid microglial cells with increased CD45 or HLA-DR intensity and hypertrophied astrocytes with increased glial fibrillary acidic protein labelling. Further, changes to extracellular matrix proteins like collagen, galectin, and tenascin-C suggested glial cells' influence on structural changes in the optic nerve head. The activation of DAMPs-driven immune response and the classical complement cascade was reported and found to be associated with activated glial cells in glaucomatous tissue. Increased pro-inflammatory markers such as interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-α) were also linked to glial cells. Glial cell activation was also associated with mitochondrial, vascular, metabolic and antioxidant component disruptions. Association of the activated glial cells with pro-inflammatory responses, dysregulation of homeostatic components and antigen presentation indicates that glial cell responses influence glaucoma progression. However, the exact mechanism triggering these responses and underlying interactions remains unexplored. This necessitates further research using human samples for an increased understanding of the precise role of neuroinflammation in glaucoma progression.

Quantitative Proteomics Reveal Region-Specific Alterations in Neuroserpin-Deficient Mouse Brain and Retina: Insights into Serpini1 Function.

Neural regeneration and neuroprotection represent strategies for future management of neurodegenerative disorders such as Alzheimer's disease (AD) or glaucoma. However, the complex molecular mechanisms that are involved in neuroprotection are not clearly understood. A promising candidate that maintains neuroprotective signaling networks is neuroserpin (Serpini1), a serine protease inhibitor expressed in neurons which selectively inhibits extracellular tissue-type plasminogen activator (tPA)/plasmin and plays a neuroprotective role during ischemic brain injury. Abnormal function of this protein has been implicated in several conditions including stroke, glaucoma, AD, and familial encephalopathy with neuroserpin inclusion bodies (FENIB). Here, we explore the potential biochemical roles of Serpini1 by comparing proteome changes between neuroserpin-deficient (NS-/-) and control mice, in the retina (RE), optic nerve (ON), frontal cortex (FC), visual cortex (VC), and cerebellum (CB). To achieve this, a multiple-plex quantitative proteomics approach using isobaric tandem mass tag (TMT) technology was employed followed by functional enrichment and protein-protein interaction analysis. We detected around 5000 proteins in each tissue and a pool of 6432 quantified proteins across all regions, resulting in a pool of 1235 differentially expressed proteins (DEPs). Principal component analysis and hierarchical clustering highlighted similarities and differences in the retina compared to various brain regions, as well as differentiating NS-/- proteome signatures from control samples. The visual cortex revealed the highest number of DEPs, followed by cerebellar regions. Pathway analysis unveiled region-specific changes, including visual perception, focal adhesion, apoptosis, glutamate receptor activation, and supramolecular fiber organization in RE, ON, FC, VC, and CB, respectively. These novel findings provide comprehensive insights into the region-specific networking of Serpini1 in the central nervous system, further characterizing its potential role as a neuroprotective agent. Data are available via ProteomeXchange with identifier PXD046873.

The role of myelin in neurodegeneration: implications for drug targets and neuroprotection strategies.

Myelination of axons in the central nervous system offers numerous advantages, including decreased energy expenditure for signal transmission and enhanced signal speed. The myelin sheaths surrounding an axon consist of a multi-layered membrane that is formed by oligodendrocytes, while specific glycoproteins and lipids play various roles in this formation process. As beneficial as myelin can be, its dysregulation and degeneration can prove detrimental. Inflammation, oxidative stress, and changes in cellular metabolism and the extracellular matrix can lead to demyelination of these axons. These factors are hallmark characteristics of certain demyelinating diseases including multiple sclerosis. The effects of demyelination are also implicated in primary degeneration in diseases such as glaucoma and Alzheimer's disease, as well as in processes of secondary degeneration. This reveals a relationship between myelin and secondary processes of neurodegeneration, including resultant degeneration following traumatic injury and transsynaptic degeneration. The role of myelin in primary and secondary degeneration is also of interest in the exploration of strategies and targets for remyelination, including the use of anti-inflammatory molecules or nanoparticles to deliver drugs. Although the use of these methods in animal models of diseases have shown to be effective in promoting remyelination, very few clinical trials in patients have met primary end points. This may be due to shortcomings or considerations that are not met while designing a clinical trial that targets remyelination. Potential solutions include diversifying disease targets and requiring concomitant interventions to promote rehabilitation.

Molecular Mechanisms of Glaucoma Pathogenesis with Implications to Caveolin Adaptor Protein and Caveolin-Shp2 Axis.

Glaucoma is a common retinal disorder characterized by progressive optic nerve damage, resulting in visual impairment and potential blindness. Elevated intraocular pressure (IOP) is a major risk factor, but some patients still experience disease progression despite IOP-lowering treatments. Genome-wide association studies have linked variations in the Caveolin1/2 (CAV-1/2) gene loci to glaucoma risk. Cav-1, a key protein in caveolae membrane invaginations, is involved in signaling pathways and its absence impairs retinal function. Recent research suggests that Cav-1 is implicated in modulating the BDNF/TrkB signaling pathway in retinal ganglion cells, which plays a critical role in retinal ganglion cell (RGC) health and protection against apoptosis. Understanding the interplay between these proteins could shed light on glaucoma pathogenesis and provide potential therapeutic targets.

Signalling pathways and cell death mechanisms in glaucoma: Insights into the molecular pathophysiology.

Glaucoma is a complex multifactorial eye disease manifesting in retinal ganglion cell (RGC) death and optic nerve degeneration, ultimately causing irreversible vision loss. Research in recent years has significantly enhanced our understanding of RGC degenerative mechanisms in glaucoma. It is evident that high intraocular pressure (IOP) is not the only contributing factor to glaucoma pathogenesis. The equilibrium of pro-survival and pro-death signalling pathways in the retina strongly influences the function and survival of RGCs and optic nerve axons in glaucoma. Molecular evidence from human retinal tissue analysis and a range of experimental models of glaucoma have significantly contributed to unravelling these mechanisms. Accumulating evidence reveals a wide range of molecular signalling pathways that can operate -either alone or via intricate networks - to induce neurodegeneration. The roles of several molecules, including neurotrophins, interplay of intracellular kinases and phosphates, caveolae and adapter proteins, serine proteases and their inhibitors, nuclear receptors, amyloid beta and tau, and how their dysfunction affects retinal neurons are discussed in this review. We further underscore how anatomical alterations in various animal models exhibiting RGC degeneration and susceptibility to glaucoma-related neuronal damage have helped to characterise molecular mechanisms in glaucoma. In addition, we also present different regulated cell death pathways that play a critical role in RGC degeneration in glaucoma.

Anti-inflammatory Effects of Siponimod in a Mouse Model of Excitotoxicity-Induced Retinal Injury.

Glaucoma is a leading cause of permanent blindness worldwide and is characterized by neurodegeneration linked to progressive retinal ganglion cell (RGC) death, axonal damage, and neuroinflammation. Glutamate excitotoxicity mediated through N-methyl-D-aspartate (NMDA) receptors plays a crucial role in glaucomatous RGC loss. Sphingosine 1-phosphate receptors (S1PRs) are important mediators of neurodegeneration and neuroinflammation in the brain and the retina. Siponimod is an immunomodulatory drug for multiple sclerosis and is a selective modulator of S1PR subtypes 1 and 5 and has been shown to have beneficial effects on the central nervous system (CNS) in degenerative conditions. Our previous study showed that mice administered orally with siponimod protected inner retinal structure and function against acute NMDA excitotoxicity. To elucidate the molecular mechanisms behind these protective effects, we investigated the inflammatory pathways affected by siponimod treatment in NMDA excitotoxicity model. NMDA excitotoxicity resulted in the activation of glial cells coupled with upregulation of the inflammatory NF-kB pathway and increased expression of TNFα, IL1-ß, and IL-6. Siponimod treatment significantly reduced glial activation and suppressed the pro-inflammatory pathways. Furthermore, NMDA-induced activation of NLRP3 inflammasome and upregulation of neurotoxic inducible nitric oxide synthase (iNOS) were significantly diminished with siponimod treatment. Our data demonstrated that siponimod induces anti-inflammatory effects via suppression of glial activation and inflammatory singling pathways that could protect the retina against acute excitotoxicity conditions. These findings provide insights into the anti-inflammatory effects of siponimod in the CNS and suggest a potential therapeutic strategy for neuroinflammatory conditions.

Retinal thickness and vascular parameters using optical coherence tomography in Alzheimer's disease: a meta-analysis.

Examining the retinal tissue has the potential to provide a unique method and technique to quantify Alzheimer's disease-related changes in participants at various stages of the disease. In this meta-analysis, we aimed to investigate the association of various optical coherence tomography parameters with Alzheimer's disease and whether retinal measurements can be used to differentiate between Alzheimer's disease and control subjects. Scientific databases including Google Scholar, Web of Science, and PubMed were systematically searched for published articles that evaluated retinal nerve fiber layer thickness and retinal microvascular network in Alzheimer's disease and control subjects. Seventy-three studies (5850 participants, including 2249 Alzheimer's disease patients and 3601 controls) were included in this meta-analysis. Relative to controls, Alzheimer's disease patients had a significantly lower global retinal nerve fiber layer thickness (standardized mean difference [SMD] = -0.79, 95% confidence intervals [CI]: -1.03 to -0.54, P < 0.00001) as well as each quadrant being thinner in Alzheimer's disease versus controls. Regarding macular parameters, values measured by optical coherence tomography were significantly lower in Alzheimer's disease than controls for macular thickness (pooled SMD: -0.44, 95% CI: -0.67 to -0.20, P = 0.0003), foveal thickness (pooled SMD = -0.39, 95% CI: -0.58 to -0.19, P < 0.0001), ganglion cell inner plexiform layer (SMD = -1.26, 95% CI: -2.24 to -0.27, P = 0.01) and macular volume (pooled SMD = -0.41, 95% CI -0.76 to -0.07, P = 0.02). Analysis using optical coherence tomography angiography parameters revealed mixed results between Alzheimer's disease and controls. Superficial vessel density (pooled SMD = -0.42, 95% CI: -0.68 to -0.17, P = 0.0001) and deep vessel density (pooled SMD = -0.46, 95% CI: -0.75 to -0.18, P = 0.001) were found to be thinner in Alzheimer's disease patients whereas the foveal avascular zone (SMD = 0.84, 95% CI: 0.17-1.51, P = 0.01) was larger in controls. Vascular density and thickness of various retinal layers were decreased in Alzheimer's disease patients compared to controls. Our results provide evidence for optical coherence tomography technology having the potential to detect retinal and microvascular changes in patients diagnosed with Alzheimer's disease and aid in monitoring and early diagnosis methods.

Oxidative Stress Induced Dysfunction of Protein Synthesis in 661W Mice Photoreceptor Cells.

Photoreceptor cells are highly susceptible to oxidative-stress-induced damage due to their high metabolic rate. Oxidative stress plays a key role in driving pathological events in several different ocular diseases, which lead to retinal degeneration and ultimately blindness. A growing number of studies have been performed to understand downstream events caused by ROS induced oxidative stress in photoreceptor cells; however, the underlying mechanisms of ROS toxicity are not fully understood. To shed light on ROS induced downstream pathological events, we employed a tandem mass tag (TMT) labelling-based quantitative mass-spectrometric approach to determine proteome changes in 661W photoreceptor cells following oxidative stress induction via the application of different concentrations of H2O2 at different time points. Overall, 5920 proteins were identified and quantified, and 450 differentially expressed proteins (DEPs) were identified, which were altered in a dose and time dependent manner in all treatment groups compared to the control group. These proteins were involved in several biological pathways, including spliceosome and ribosome response, activated glutathione metabolism, decreased ECM-receptor interaction, oxidative phosphorylation, abnormally regulated lysosome, apoptosis, and ribosome biogenesis. Our results highlighted ECM receptor interaction, oxidative phosphorylation and spliceosome pathways as the major targets of oxidative stress that might mediate vascular dysfunction and cellular senescence.

Neuroserpin gene therapy inhibits retinal ganglion cell apoptosis and promotes functional preservation in glaucoma.

Our research has proven that the inhibitory activity of the serine protease inhibitor neuroserpin (NS) is impaired because of its oxidation deactivation in glaucoma. Using genetic NS knockout (NS-/-) and NS overexpression (NS+/+ Tg) animal models and antibody-based neutralization approaches, we demonstrate that NS loss is detrimental to retinal structure and function. NS ablation was associated with perturbations in autophagy and microglial and synaptic markers, leading to significantly enhanced IBA1, PSD95, beclin-1, and LC3-II/LC3-I ratio and reduced phosphorylated neurofilament heavy chain (pNFH) levels. On the other hand, NS upregulation promoted retinal ganglion cell (RGC) survival in wild-type and NS-/- glaucomatous mice and increased pNFH expression. NS+/+Tg mice demonstrated decreased PSD95, beclin-1, LC3-II/LC3-I ratio, and IBA1 following glaucoma induction, highlighting its protective role. We generated a novel reactive site NS variant (M363R-NS) resistant to oxidative deactivation. Intravitreal administration of M363R-NS was observed to rescue the RGC degenerative phenotype in NS-/- mice. These findings demonstrate that NS dysfunction plays a key role in the glaucoma inner retinal degenerative phenotype and that modulating NS imparts significant protection to the retina. NS upregulation protected RGC function and restored biochemical networks associated with autophagy and microglial and synaptic function in glaucoma.

Extracellular vesicles as reconfigurable therapeutics for eye diseases: Promises and hurdles.

A large number of people worldwide suffer from visual impairment. However, most available therapies rely on impeding the development of a particular eye disorder. Therefore, there is an increasing demand for effective alternative treatments, specifically regenerative therapies. Extracellular vesicles, including exosomes, ectosomes, or microvesicles, are released by cells and play a potential role in regeneration. Following an introduction to EV biogenesis and isolation methods, this integrative review provides an overview of our current knowledge about EVs as a communication paradigm in the eye. Then, we focused on the therapeutic applications of EVs derived from conditioned medium, biological fluid, or tissue and highlighted some recent developments in strategies to boost the innate therapeutic potential of EVs by loading various kinds of drugs or being engineered at the level of producing cells or EVs. Challenges faced in the development of safe and effective translation of EV-based therapy into clinical settings for eye diseases are also discussed to pave the road toward reaching feasible regenerative therapies required for eye-related complications.

Chitosan modified 5-fluorouracil nanostructured lipid carriers for treatment of diabetic retinopathy in rats: A new dimension to an anticancer drug.

Diabetic retinopathy (DR) is one of the chronic complications of diabetes. It includes retinal blood vessels' damage. If untreated, it leads to loss of vision. The existing treatment strategies for DR are expensive, invasive, and need expertise during administration. Hence, there is a need to develop a non-invasive topical formulation that can penetrate deep to the posterior segment of retina and treat the damaged retinal vessels. In addition, it should also provide sustained release. In recent years, novel drug delivery systems (NDDS) have been explored for treating DR and found successful. In this study, chitosan (CS) modified 5-Fluorouracil Nanostructured Lipid Carriers (CS-5-FU-NLCs) were prepared by modified melt emulsification-ultrasonication method and optimized by Box-Behnken Design. The size, polydispersity index, zeta potential and entrapment efficiency of CS-5-FU-NLCs were 163.2 ± 2.3 nm, 0.28 ± 1.52, 21.4 ± 0.5 mV and 85.0 ± 0.2 %, respectively. The in vitro drug release and ex vivo permeation study confirmed higher and sustained drug release in CS-5-FU-NLCs as compared to 5-FU solution. HET-CAM Model ensured the non-irritant nature of CS-5-FU-NLCs. In vivo ocular studies of CS-5-FU-NLCs confirmed antiangiogenic effect of 5-FU by CAM model and diabetic retinopathy induced rat model, indicating successful delivery of 5-FU to the retina.

Computational refinement identifies functional destructive single nucleotide polymorphisms associated with human retinoid X receptor gene.

Alterations in the nuclear retinoid X receptor (RXRs) signalling have been implicated in neurodegenerative disorders such as Alzheimer's disease, Parkinson's disease, stroke, multiple sclerosis and glaucoma. Single nucleotide polymorphisms (SNPs) are the main cause underlying single nucleic acid variations which in turn determine heterogeneity within various populations. These genetic polymorphisms have been suggested to associate with various degenerative disorders in population-wide analysis. This bioinformatics study was designed to investigate, search, retrieve and identify deleterious SNPs which may affect the structure and function of various RXR isoforms through a computational and molecular modelling approach. Amongst the 1,813 retrieved SNPs several were found to be deleterious with rs140464195_G139R, rs368400425_R358W and rs368586400_L383F RXRα mutant variants being the most detrimental ones causing changes in the interatomic interactions and decreasing the flexibility of the mutant proteins. Molecular genetics analysis identified seven missense mutations in RXRα/ß/γ isoforms. Two novel mutations SNP IDs (rs1588299621 and rs1057519958) were identified in RXRα isoform. We used several in silico prediction tools such as SIFT, PolyPhen, I-Mutant, Protein Variation Effect Analyzer (PROVEAN), PANTHER, SNP&Go, PhD-SNP and SNPeffect to predict pathogenicity and protein stability associated with RXR mutations. The structural assessment by DynaMut tool revealed that hydrogen bonds were affected along with hydrophobic and carbonyl interactions resulting in reduced flexibility at the mutated residue positions but ultimately stabilizing the molecule as a whole. Summarizing, analysis of the missense mutations in RXR isoforms showed a mix of conclusive and inconclusive genotype-phenotype correlations suggesting the use of sophisticated computational analysis tools for studying RXR variants.Communicated by Ramaswamy H. Sarma.

Siponimod exerts neuroprotective effects on the retina and higher visual pathway through neuronal S1PR1 in experimental glaucoma.

Sphingosine-1-phosphate receptor (S1PR) signaling regulates diverse pathophysiological processes in the central nervous system. The role of S1PR signaling in neurodegenerative conditions is still largely unidentified. Siponimod is a specific modulator of S1P1 and S1P5 receptors, an immunosuppressant drug for managing secondary progressive multiple sclerosis. We investigated its neuroprotective properties in vivo on the retina and the brain in an optic nerve injury model induced by a chronic increase in intraocular pressure or acute N-methyl-D-aspartate excitotoxicity. Neuronal-specific deletion of sphingosine-1-phosphate receptor (S1PR1) was carried out by expressing AAV-PHP.eB-Cre recombinase under Syn1 promoter in S1PR1flox/flox mice to define the role of S1PR1 in neurons. Inner retinal electrophysiological responses, along with histological and immunofluorescence analysis of the retina and optic nerve tissues, indicated significant neuroprotective effects of siponimod when administered orally via diet in chronic and acute optic nerve injury models. Further, siponimod treatment showed significant protection against trans-neuronal degenerative changes in the higher visual center of the brain induced by optic nerve injury. Siponimod treatment also reduced microglial activation and reactive gliosis along the visual pathway. Our results showed that siponimod markedly upregulated neuroprotective Akt and Erk1/2 activation in the retina and the brain. Neuronal-specific deletion of S1PR1 enhanced retinal and dorsolateral geniculate nucleus degenerative changes in a chronic optic nerve injury condition and attenuated protective effects of siponimod. In summary, our data demonstrated that S1PR1 signaling plays a vital role in the retinal ganglion cell and dorsolateral geniculate nucleus neuronal survival in experimental glaucoma, and siponimod exerts direct neuroprotective effects through S1PR1 in neurons in the central nervous system independent of its peripheral immuno-modulatory effects. Our findings suggest that neuronal S1PR1 is a neuroprotective therapeutic target and its modulation by siponimod has positive implications in glaucoma conditions.