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Purpose The DBA/2J mouse has been described as a model for congenital experimental glaucoma. It develops anterior segment anomalies with synechiae and pigment dispersion leading to raised intraocular pressure (IOP) and glaucomatous damage. However there are serious practical considerations when using this model in longitudinal studies. Methods We followed 118 mice from 12 - 48 weeks of age in a pharmaceutical trial. Here we report on the findings in control animals (n=37). IOP was measured weekly, electrophysiology and optical coherence tomography (OCT) every 6 weeks. A subset also had invasive IOP measurements performed prior to euthanasia. Results While IOP eventually rose by 9 months in most animals, tonometry was complicated by corneal calcification in the majority of animals rendering IOP measurement unreliable. Invasive IOP did not correlate with non-invasive measures. Loss of scotopic threshold response and thinning of inner retinal layers on OCT was observed over time, suggesting glaucomatous damage but this occurred in some animals without raised IOP. Poor pupil dilation significantly affected electrophysiology, OCT and fundus imaging. 22% of animals developed major systemic complications leading to high dropout rate. Conclusions The DBA/2J experimental glaucoma model shows variability in expression and its pathological changes cause major difficulties in assessing disease progression. From our experience the model presents significant challenges for drug studies in glaucoma, as there are many confounding factors; difficulty with accurate IOP measurement, in vivo imaging, and electrophysiology recording and a high drop-out rate. In addition there may be an underlying neurodegenerative process independent of IOP.

The caveolin (Cav) family of proteins comprises key constituents of caveolar structures in cell membranes, which are involved in receptor-independent endocytosis and cellular signalling pathways. Three isoforms of caveolin viz. cav-1, cav-2 and cav-3 encoded by CAV1 , CAV2 and CAV3 genes respectively, have been reported to be expressed in various tissues. Genetic polymorphism in CAV has been identified as associated with the development of pathological changes in the cardiovascular system, chronic kidney disease as well as neurodegenerative diseases of the brain and retina such as Alzheimer's disease, Parkinson's disease and glaucoma. In this study, we investigate and characterise various polymorphisms associated with CAV1 , CAV2 and CAV3 by using a combination of in silico algorithms such as SIFT, Polyphen 2.0, I-Mutant, PROVEAN, PANTHER, SNP&Go, PhD-SNP, MutPred and SNPEffects. Three-dimensional comparative modelling was performed using Phyre2 server, ab initio modelling, using the I-TASSER and RaptorX program. The predicted models were evaluated using Ramachandran plot to establish the accuracy of the models generated. The resulting mutant and wild type proteins obtained were energy minimized in Swiss Deep Viewer and evaluated. The study has identified two of the non-synonymous single nucleotide polymorphism (nsSNP) in CAV3 gene that may have a damaging effect on the protein stability. The surface residues in the wild type and mutant forms highlight different accessible surface area (ASA) of amino acid residues in the corresponding proteins. Our analysis predicted that none of the known nsSNPs have a negative effect on the CAV1 and CAV2 protein structures. Phylogenetic analysis using ConSurf further identified that most of the disease-associated nsSNPs were within the conserved regions in human cav3.

Accumulation of amyloid β (Aβ) and its aggregates in the ageing central nervous system is regarded synonymous to Alzheimer's disease (AD) pathology. Despite unquestionable advances in mechanistic and diagnostic aspects of the disease understanding, the primary cause of Aβ accumulation as well as its in vivo roles remains elusive; nonetheless, the majority of the efforts to address pathological mechanisms for therapeutic development are focused towards moderating Aβ accumulation in the brain. More recently, Aβ deposition has been identified in the eye and is linked with distinct age-related diseases including age-related macular degeneration, glaucoma as well as AD. Awareness of the Aβ accumulation in these markedly different degenerative disorders has led to an increasing body of work exploring overlapping mechanisms, a prospective biomarker role for Aβ and the potential to use retina as a model for brain related neurodegenerative disorders. Here, we present an integrated view of current understanding of the retinal Aβ deposition discussing the accumulation mechanisms, anticipated impacts and outlining ameliorative approaches that can be extrapolated to the retina for potential therapeutic benefits. Further longitudinal investigations in humans and animal models will determine retinal Aβ association as a potential pathognomonic, diagnostic or prognostic biomarker.

TrkB is a high affinity receptor for the brain derived neurotrophic factor (BDNF) and its phosphorylation stimulates activation of several intracellular signalling pathways linked to cellular growth, differentiation and maintenance. Identification of various activators and inhibitors of the TrkB receptor and greater understanding their binding mechanisms is critical to elucidate the biochemical and pharmacological pathways and analyse various protein crystallization studies. The data presented here is related to the research article entitled “Brain Derived neurotrophic factor is involved in the regulation of glycogen synthase kinase 3β (GSK3β) signalling” [1]. Cyclotraxin B (CTXB) is a disulphide bridge linked cyclic peptide molecule that interacts with TrkB receptor and inhibits the BDNF/TrkB downstream signalling. This article reports for the first time binding mechanism and interaction parameters of CTXB with the TrkB receptor. The molecular model of CTXB has been generated and it’s docking with TrkB domain carried out to determine the critical residues involved in the protein peptide interaction. Keywords: TrkB, Cyclotraxin B, GSK3β, Docking

The noradrenaline transporter (NAT) transfers noradrenaline released into the synaptic cleft back into the presynaptic terminal, thus terminating neurotransmission. Although the distribution of NAT within the central nervous system has been well-characterized, less is known about its distribution elsewhere in the peripheral nervous system and in organs such as the skin. To address this in the present study, NAT expression was investigated using immunohistochemistry in the hind paw skin and more proximally in the sciatic nerve, dorsal root ganglia and spinal cord of five male Wistar rats. It was hypothesised that NAT would be expressed exclusively on nerve fibres labelled by dopamine beta hydroxylase (DβH), an enzyme involved in the conversion of dopamine to noradrenaline. NAT co-localised with DβH in neurons in the spinal cord, dorsal root ganglia and sciatic nerve. Unexpectedly, however, NAT-like immunoreactivity was not observed in DβH immuno-reactive fibres that innervated dermal blood vessels, suggesting that a mechanism other than presynaptic re-uptake of noradrenaline through NAT regulates transmission at neurovascular junctions in the skin. Furthermore, a novel association between NAT-like immunoreactivity and the myelin marker myelin basic protein (MBP) was identified in peripheral nerves. Specifically, NAT and MBP appeared to congregate around primary afferent nerve fibres labelled by neurofilament 200, a marker of neurons with medium- and large-diameter axons. NAT-like immunoreactivity was also detected in cultured Schwann cells immunohistochemically and at the mRNA level. Together, these findings imply a hitherto unrecognised role of Schwann cells in clearance of noradrenaline in the peripheral nervous system.

Neuroserpin is a serine protease inhibitor that regulates the activity of plasmin and its activators in the neuronal tissues. This study provides novel evidence of regulatory effect of the neuroserpin on plasmin proteolytic activity in the retina in glaucoma. Human retinal and vitreous tissues from control and glaucoma subjects as well as retinas from experimental glaucoma rats were analysed to establish changes in plasmin and neuroserpin activity. Neuroserpin undergoes oxidative inactivation in glaucoma which leads to augmentation of plasmin activity. Neuroserpin contains several methionine residues in addition to a conserved reactive site methionine and our study revealed enhanced oxidation of Met residues in the serpin under glaucoma conditions. Met oxidation was associated with loss of neuroserpin inhibitory activity and similar findings were observed in the retinas of superoxide dismutase (SOD) mutant mice that have increased oxidative stress. Treatment of purified neuroserpin with H2O2 further established that Met oxidation inversely correlated with its plasmin inhibitory activity. Dysregulation of the plasmin proteolytic system associated with increased degradation of the extracellular matrix (ECM) proteins in the retina. Collectively, these findings delineate a novel molecular basis of plasmin activation in glaucoma and potentially for other neuronal disorders with implications in disease associated ECM remodelling.

AbstarctGlaucoma is a chronic disease that shares many similarities with other neurodegenerative disorders of the central nervous system. This study was designed to evaluate the association between glaucoma and other neurodegenerative disorders by investigating glaucoma-associated protein changes in the retina and vitreous humour. The multiplexed Tandem Mass Tag based proteomics (TMT-MS3) was carried out on retinal tissue and vitreous humour fluid collected from glaucoma patients and age-matched controls followed by functional pathway and protein network interaction analysis. About 5000 proteins were quantified from retinal tissue and vitreous fluid of glaucoma and control eyes. Of the differentially regulated proteins, 122 were found linked with pathophysiology of Alzheimer’s disease (AD). Pathway analyses of differentially regulated proteins indicate defects in mitochondrial oxidative phosphorylation machinery. The classical complement pathway associated proteins were activated in the glaucoma samples suggesting an innate inflammatory response. The majority of common differentially regulated proteins in both tissues were members of functional protein networks associated brain changes in AD and other chronic degenerative conditions. Identification of previously reported and novel pathways in glaucoma that overlap with other CNS neurodegenerative disorders promises to provide renewed understanding of the aetiology and pathogenesis of age related neurodegenerative diseases.

© 2016 Elsevier Ireland Ltd. The APP-PS1δE9 mouse model of Alzheimer's disease (AD) exhibits age dependent amyloid β (Aβ) plaque formation in their central nervous system due to high expression of mutated human APP and PSEN1 transgenes. Here we evaluated Aβ deposition and changes in soluble Aβ accumulation in the retinas of aged APP-PS1 mice using a combination of immunofluorescence, retinal flat mounts and western blotting techniques. Aβ accumulation in the retina has previously been shown to be associated with retinal ganglion cell apoptosis in animal models of glaucoma. This study investigated changes in the inner retinal function and structure in APP-PS1 mice using electrophysiology and histological approaches respectively. We report for the first time a significant decline in scotopic threshold response (STR) amplitudes which represents inner retinal function in transgenic animals compared to the wild type counterparts (p < 0.0001). Thinning of the retina particularly involving inner retinal layers and reduction in axonal density in the optic nerve was also observed. TUNEL staining was performed to examine neuronal apoptosis in the inner retina. Intraocular pressure (IOP) measurements showed that APP-PS1δE9 mice had a slightly elevated IOP, but the significance of this finding is not yet known. Together, these results substantiate previous observations and highlight that APP-PS1δE9 mice show evidence of molecular, functional and morphological degenerative changes in the inner retina.