The Canadian Consortium on Neurodegeneration in Aging (CCNA) was created by the Canadian federal government through its health research funding agency, the Canadian Institutes for Health Research (CIHR), in 2014, as a response to the G7 initiative to fight dementia. Two five-year funding cycles (2014-2019; 2019-2024) have occurred following peer review, and a third cycle (Phase 3) has just begun. A unique construct was mandated, consisting of 20 national teams in Phase I and 19 teams in Phase II (with research topics spanning from basic to clinical science to health resource systems) along with cross-cutting programs to support them. Responding to the needs of researchers within the CCNA teams, a unique sample of 1173 deeply phenotyped patients with various forms of dementia was accrued and studied over eight years (COMPASS-ND). In the second phase of funding (2019-2024), a national dementia prevention program (CAN-THUMBS UP) was set up. In a short time, this prevention program became a member of the World Wide FINGERS prevention consortium. In this article, the challenges, successes, and impacts of CCNA in Canada and internationally are discussed. Short-term deliverables have occurred, along with considerable promise of impacts in the longer term. The creation of synergy, networking, capacity building, engagement of people with lived experience, and economies of scale have contributed to the considerable success of CCNA by all measures. CCNA is evidence that an organized "centrally-organized" approach to dementia research can catalyze important progress nationally and yield significant and measurable results.

Glaucoma is a chronic neurodegenerative disorder characterized by progressive damage and loss of retinal ganglion cells (RGCs). It is considered one of the leading causes of irreversible blindness in the older population. There are estimates that glaucoma will affect 80 million individuals worldwide by the end of this decade, and yet we are still not able to identify the signals and the mechanisms that trigger this neurodegenerative disease. Various hypotheses have been generated to address the causes of the progressive RGC death that characterizes the disease. Age and increased intraocular pressure (IOP) have been established as the main risk factors for the development of glaucoma. Recent studies have identified additional factors that play a role in the pathogenesis of this complex multifactorial disease, including inflammation, oxidative stress, vascular dysregulation, disrupted axonal transport of neurotrophic factors, and the release of neurotoxic agents such as glutamate, nitric oxide and free radicals. The currently approved therapies for glaucoma that seek to reduce IOP, including medications, laser treatment, and surgery, are unable to reliably stop RGC loss and functional impairment. Considering the significant personal, medical and socio-economic impacts of glaucoma as a leading cause of blindness, there is a pressing need for new innovative treatment strategies. Here we focus on the role of neuroinflammation in glaucoma and the opportunities that new findings in this area have for the development of future therapeutics.

Background: Prenatal alcohol exposure is the leading preventable cause of behavioral and cognitive deficits, which may affect between 2 and 5 % of children in North America. While the underlying mechanisms of alcohol's effects on development remain relatively unknown, emerging evidence implicates epigenetic mechanisms in mediating the range of symptoms observed in children with fetal alcohol spectrum disorder (FASD). Thus, we investigated the effects of prenatal alcohol exposure on genome-wide DNA methylation in the NeuroDevNet FASD cohort, the largest cohort of human FASD samples to date.Methods: Genome-wide DNA methylation patterns of buccal epithelial cells (BECs) were analyzed using the Illumina HumanMethylation450 array in a Canadian cohort of 206 children (110 FASD and 96 controls). Genotyping was performed in parallel using the Infinium HumanOmni2.5-Quad v1.0 BeadChip.Results: After correcting for the effects of genetic background, we found 658 significantly differentially methylated sites between FASD cases and controls, with 41 displaying differences in percent methylation change >5 %. Furthermore, 101 differentially methylated regions containing two or more CpGs were also identified, overlapping with 95 different genes. The majority of differentially methylated genes were highly expressed at the level of mRNA in brain samples from the Allen Brain Atlas, and independent DNA methylation data from cortical brain samples showed high correlations with BEC DNA methylation patterns. Finally, overrepresentation analysis of genes with up-methylated CpGs revealed a significant enrichment for neurodevelopmental processes and diseases, such as anxiety, epilepsy, and autism spectrum disorders.Conclusions: These findings suggested that prenatal alcohol exposure is associated with distinct DNA methylation patterns in children and adolescents, raising the possibility of an epigenetic biomarker of FASD.

Additional file 5: Table S4. Table of pyrosequencing primers.

Background: Significant protease activations have been reported after traumatic brain injury (TBI). These proteases are responsible for cleavage of transmembrane proteins in neurons, glial, and endothelial cells and this results in the release of their extracellular domains (ectodomains).Methods: Two TBI models were employed here, representing both closed head injury (CHI) and open head injury (OHI). In situ zymography, immunohistochemistry, bright field and confocal microscopy, quantification of immunopositive cells and statistical analysis were applied.Results: We found, using in situ zymography, that gelatinase activity of matrix metalloproteinases (MMP)-2 and MMP-9 was upregulated in cortex of both injury models. Using immunohistochemistry for several MPPs (Matrix metalloproteinases) and ADAMs (disintegrin and metalloproteinases), including MMP-2, -9, ADAM-10, -17, distinct patterns of induction were observed in the two TBI models. In closed head injury, an early increase in protein expression of MMP-2, -9 and ADAM -17 was found as early as 10 min post injury in cortex and peaked at 1 h for all 4 proteases examined. In contrast, after OHI the maximal expression was observed locally neighboring the impact site, at a later time-point, as long as 24 h after the injury for MMP-2 and MMP-9. Confocal microscopy revealed colocalization of the 4 proteases with the neuronal marker NeuN in CHI, but only MMP2 colocalized with NeuN in OHI.Conclusions: The findings may lead to a trauma-induced therapeutic strategy triggered soon after a primary insult to improve survival and to reduce brain damage following TBI. (C) 2016 Published by Elsevier Ltd.

The functional organization of intrinsic con- nections within area 18 of cat visual cortex was studied using combined electrophysiological and anatomical techniques. Physiological recordings were first used to map the distribu- tion of orientation preference, ocular dominance, and recep- tive-field location relative to the cortical surface. Next, local- ized injections of lectin-conjugated horseradish peroxidase were made into physiologically identified regions within area 18. We found that (i) the local cortical interconnections are made preferentially between cell populations with orthogonal preferred orientations and are independent of the ocular domi- nance of the cortical cells, (ii) the map of visual space in the cortex is anisotropic with the magnification factor for vertical at least twice that for horizontal visual space, and (iii) the pat- tern of cortical projections compensates for the functional asymmetry so that a population of interconnected cells repre- sents a roughly circular region of visual space.

: Traumatic eye injury (TEI) is one of the leading causes of monocular blindness in military personnel and young males worldwide. This profound and frequently irreversible posttraumatic loss of vision has a poor prognosis due to retinal cell death, scar formation, and lack of functional regeneration. Proliferative vitreoretinopathy (PVR), a form of intraocular fibrosis, is often the primary reason for the loss of vision after ocular trauma, and frequently occurs after blunt trauma and open globe injuries caused by penetration, rupture, perforation, and presence of intraocular foreign bodies as well as after retinal re-attachment surgery. We genetically engineered protease activity sensor (PAS) as chimeric transmembrane protein that can respond to increase in metalloproteinase activity by shedding/releasing tagged-ectodomains in the vicinity of affected cells after traumatic eye injury and induction of PVR. We demonstrated that upon infection with AAV carrying our construct, HEK293 cells and neurons in culture expressed the engineered HA-tagged PAS proteins. Their HA-tagged ectodomains were detected in the extracellular medium within minutes following stimulation with ionomycin and glutamate respectively. We used a rabbit PVR model of ocular trauma in which autologous blood was injected into the vitreous cavity of one eye after a surgical incision through the pars plana. We have successfully developed engineered adeno-associated virus (AAV) with CAG and CMV promoters, to transduce primary cortical neurons and retinal cells. These vectors will be applied in vivo to deliver therapeutic genes after ocular trauma.

The brain undergoes rapid changes throughout development. Balancing the formation and elimination of synapses is essential for proper neural circuit formation. Many of these processes are driven by activity the brain receives during development. Therefore, a significant amount of time and effort has been given to understanding how activity shapes the brain. Current in vitro and in vivo methods have provided us with many insights. However, with in vivo methods, it is difficult to observe the changes that occur at the molecular level. Current in vitro methods allow us to see those molecular changes but regional influences of activity is difficult to control. We begin bridge the gap between the two modes of analysis by using microfluidics. Through the use of 3-compartment microfluidic chambers, neuronal cell bodies are both physically and environmentally isolated while their axons are free to interact between groups of cells. Here we outline the steps to establish such a system.

TDP-43 (TAR DNA binding protein 43) is a heterogeneous nuclear ribonucleoprotein (hnRNP) that has been found to play an important role in neurodegenerative diseases. TDP-43’s involvement in nuclear factor-kappaB pathways has been reported in both neurons and microglial cells. The NF-κB pathway targets hundreds of genes, many of which are involved in inflammation, immunity and cancer. p50/p65 (p50/RelA) heterodimers, as the major Rel complex in the NF-κB family, are induced by diverse external physiological stimuli and modulate transcriptional activity in almost all cell types. Both p65 and TDP-43 translocation occur through the classic nuclear transportation system. In this study, we report that TDP-43 overexpression prevents TNF-α induced p65 nuclear translocation in a dose dependent manner, and that this further inhibits p65 transactivation activity. The inhibition by TDP-43 does not occur through preventing IκB degradation but probably by competing for the nuclear transporter-importin α3 (KPNA4). This competition is dependent on the presence of the nuclear localization signal (NLS) in TDP-43. Silencing TDP-43 using a specific siRNA also increased p65 nuclear localization upon TNF-α stimulation, suggesting that endogenous TDP-43 may be a default suppressor of the NF-κB pathway. Our results indicate that TDP-43 may play an important role in regulating the levels of NF-κB activity by controlling the nuclear translocation of p65.

Synaptic competition is widely believed to be central to the formation and function of neuronal networks, yet the underlying mechanisms are poorly described. To investigate synaptic competition in vitro, we have developed a novel two input pathway competition model using a 3-compartment microfluidic device. Axons from cultured rat cortical neurons from two different lateral compartments (inputs) innervate a common neuronal population in a separate central compartment. Inhibiting one input's activity, using the GABAAR agonist muscimol, resulted in increased synapse numbers and axon elongation of the opposing untreated (uninhibited) inputs in the central compartment. Time lapse imaging revealed that uninhibited inputs outgrew and outconnected their inhibited counterparts. This form of competition occurs during a sensitive period ending prior to 21 DIV and is NMDAR and CamKII dependent. Surprisingly, this form of plasticity was dependent on the age of the center compartment neurons but not of the competing inputs.

Secretory trafficking through the Golgi complex is critical for neuronal development, function, and stress response. Altered secretion is associated with the pathogenesis of various neurological diseases. We found that c-Jun amino-terminal kinase 3 (JNK3) inhibited secretory trafficking by promoting the depletion of phosphatidylinositol 4-phosphate (PI4P) in the Golgi complex of COS7 cells and primary rat neurons. Exposure of cultured primary rat neurons to excitotoxic concentrations of NMDA (N-methyl-d-aspartate), an agonist of a class of ionotropic glutamate receptors, or overexpression of zD17 (a palmitoyl transferase) resulted in JNK3 palmitoylation and association with the Golgi complex. Analysis of mutant constructs of JNK3 indicated that Golgi association was independent of its kinase activity but depended on its palmitoylation. The association of JNK3 with the Golgi in cultured neurons decreased the secretory trafficking of the α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor subunit GluR1 (glutamate receptor subunit 1), a component of ionotropic glutamate receptors found at glutamatergic synapses. Palmitoylated JNK3 bound to the phosphatase Sac1, increasing its abundance at the Golgi and thereby decreasing the abundance of PI4P, a lipid necessary for post-Golgi trafficking. Disrupting the JNK3-Sac1 interaction with two synthetic peptides prevented the loss of surface GluR1 and preserved synaptic integrity in cultured neurons exposed to NMDA. Together, our results suggest that JNK3 participates in an adaptive response to neuronal hyperexcitation by impeding secretory trafficking at the Golgi complex.

Loss-of-function mutations in the progranulin (GRN) gene are a common cause of autosomal dominant frontotemporal lobar degeneration, a fatal and progressive neurodegenerative disorder common in people less than 65 years of age. In the brain, progranulin is expressed in multiple regions at varying levels, and has been hypothesized to play a neuroprotective or neurotrophic role. Four neurotoxic agents were injected in vivo into constitutive progranulin knockout (Grn(-/-)) mice and their wild-type (Grn(+/+)) counterparts to assess neuronal sensitivity to toxic stress. Administration of 3-nitropropionic acid, quinolinic acid, kainic acid, and pilocarpine induced robust and measurable neuronal cell death in affected brain regions, but no differential cell death was observed between Grn(+/+) and Grn(-/-) mice. Thus, constitutive progranulin knockout mice do not have increased sensitivity to neuronal cell death induced by the acute chemical models of neuronal injury used in this study. (C) 2013 Published by Elsevier Inc.

Background: The presence of an extra whole or part of chromosome 21 in people with Down syndrome (DS) is associated with multiple neurological changes, including pathological aging that often meets the criteria for Alzheimer's Disease (AD). In addition, trisomies have been shown to disrupt normal epigenetic marks across the genome, perhaps in response to changes in gene dosage. We hypothesized that trisomy 21 would result in global epigenetic changes across all participants, and that DS patients with cognitive impairment would show an additional epigenetic signature.Methods: We therefore examined whole-genome DNA methylation in buccal epithelial cells of 10 adults with DS and 10 controls to determine whether patterns of DNA methylation were correlated with DS and/or cognitive impairment. In addition we examined DNA methylation at the APP gene itself, to see whether there were changes in DNA methylation in this population. Using the Illumina Infinium 450 K Human Methylation Array, we examined more than 485,000 CpG sites distributed across the genome in buccal epithelial cells.Results: We found 3300 CpGs to be differentially methylated between the groups, including 495 CpGs that overlap with clusters of differentially methylated probes. In addition, we found 5 probes that were correlated with cognitive function including two probes in the TSC2 gene that has previously been associated with Alzheimer's disease pathology. We found no enrichment on chromosome 21 in either case, and targeted analysis of the APP gene revealed weak evidence for epigenetic impacts related to the AD phenotype.Conclusions: Overall, our results indicated that both Trisomy 21 and cognitive impairment were associated with distinct patterns of DNA methylation.

Background TAR DNA-binding protein 43 (TDP-43) is a protein that is involved in the pathology of Amyotrophic Lateral Sclerosis (ALS) and Frontotemporal Lobar Degeneration (FTLD). In patients with these neurodegenerative diseases, TDP-43 does not remain in its normal nuclear location, but instead forms insoluble aggregates in both the nucleus and cytoplasm of affected neurons. Results We used high density peptide array analysis to identify regions in TDP-43 that are bound by TDP-43 itself and designed candidate peptides that might be able to reduce TDP-43 aggregation. We found that two of the synthetic peptides identified with this approach could effectively inhibit the formation of TDP-43 protein aggregates in a concentration-dependent manner in HeLa cells in which a mutated human TDP-43 gene was overexpressed. However, despite reducing aggregation, these peptides did not reduce or prevent cell death. Similar results were observed in HeLa cells treated with arsenite. Again we found reduced aggregation, in this case of wild type TDP-43, but no difference in cell death. Conclusions Our results suggest that TDP-43 aggregation is associated with the cell death process rather than being a direct cause.

Click to increase image sizeClick to decrease image sizeKeywords:: palmitoylationstress responseGluR1JNKPI4PSac1palmitoyl acyltransferasesynaptoprotectionthe Golgi complexzDHHC17This article is related to:

Progranulin (PGRN) haploinsufficiency accounts for up to 10% of frontotemporal lobe dementia. PGRN has also been implicated in neuroinflammation in acute and chronic neurological disorders. Here we report that both protein and mRNA levels of cortical and hippocampal PGRN are significantly enhanced following pilocarpine-induced status epilepticus. We also identify intense PGRN immunoreactivity that colocalizes with CD11b in seizure-induced animals, suggesting that PGRN elevation occurs primarily in activated microglia and macrophages. To test the role of PGRN in activation of microglia/macrophages, we apply recombinant PGRN protein directly into the hippocampal formation, and observe no change in the number of CD11b(+) microglia/macrophages in the dentate gyrus. However, with pilocarpine-induced status epilepticus, PGRN application significantly increases the number of CD11b(+) microglia/macrophages in the dentate gyrus, without affecting the extent of hilar cell death. In addition, the number of CD11b(+) microglia/macrophages induced by status epilepticus is not significantly different between PGRN knockout mice and wildtype. Our findings suggest that status epilepticus induces PGRN expression, and that PGRN potentiates but is not required for seizure-induced microglia/macrophage activation.

The NMDAR plays a unique and vital role in subcellular signaling. Calcium influx initiates signaling cascades important for both synaptic plasticity and survival; however, overactivation of the receptor leads to toxicity and cell death. This dichotomy is partially explained by the subcellular location of the receptor. NMDARs located at the synapse stimulate cell survival pathways, while extrasynaptic receptors signal for cell death. Thus far, this interplay between synaptic and extrasynaptic NMDARs has been studied exclusively in cortical (CTX) and hippocampal neurons. It was unknown whether other cell types, such as GABAergic medium-sized spiny projection neurons of the striatum (MSNs), which bear the brunt of neurodegeneration in Huntington's disease, follow the same pattern. Here we report synaptic versus extrasynaptic NMDAR signaling in striatal MSNs and resultant activation of cAMP response element binding protein (CREB), in rat primary corticostriatal cocultures. Similarly to CTX, we found in striatal MSNs that synaptic NMDARs activate CREB, whereas extrasynaptic NMDARs dominantly oppose CREB activation. However, MSNs are much less susceptible to NMDA-mediated toxicity than CTX cells and show differences in subcellular GluN2B distribution. Blocking NMDARs with memantine (30 μm) or GluN2B-containing receptors with ifenprodil (3 μm) prevents CREB shutoff effectively in CTX and MSNs, and also rescues both neuronal types from NMDA-mediated toxicity. This work may provide cell and NMDAR subtype-specific targets for treatment of diseases with putative NMDAR involvement, including neurodegenerative disorders and ischemia.