Deficits In Mouse Model Research Articles

Early Cognitive and Behavioral Deficits in Mouse Models for Tauopathy and Alzheimer's Disease.

Neurocognitive disorders, among which Alzheimer’s disease (AD), have become one of the major causes of death in developed countries. No effective disease-modifying therapy is available, possibly because current treatments are administered too late to still be able to intervene in the disease progress. AD is characterized by a gradual onset with subclinical neurobiological and behavioral changes that precede diagnosis with years to even decades. The earlier the diagnosis, the earlier potential treatments can be tested and started. Mouse models are valuable to study the possible causes underlying early phases of neuropathology and their reflection in behavior and other biomarkers, to help improve preclinical detection and diagnosis of AD. Here, we assessed cognitive functioning and social behavior in transgenic mice expressing tau pathology only (Tau-P301L) or a combination of amyloid and tau pathology [amyloid precursor protein (APP)-V717I × Tau-P301L]. The mice were subjected to a variety of behavioral tasks at an age of 3–6 months, i.e., at an early phase of their AD-like pathology. We hypothesized that compared to age-matched wild-type controls, transgenic mice would show specific impairments in both cognitive and non-cognitive tasks. In line with our expectations, transgenic mice showed decreased cognitive flexibility in the Morris water maze, decreased exploratory behavior, decreased performance in a nesting task, and increased anxiety-like behavior. In accordance with the amyloid-cascade hypothesis, some of the behavioral measures showed more severe deficits in APP-V717I × Tau-P301L compared to Tau-P301L mice, indicating an exacerbation of disease processes due to the co-occurrence of amyloid and tau pathology. Our study supports the use of behavioral markers as early indicators of ongoing AD pathology during the preclinical phase.

Diminished social interaction incentive contributes to social deficits in mouse models of autism spectrum disorder.

One of the core symptoms of autism spectrum disorder (ASD) is impaired social interaction. Currently, no pharmacotherapies exist for this symptom due to complex biological underpinnings and distinct genetic models which fail to represent the broad disease spectrum. One convincing hypothesis explaining social deficits in human ASD patients is amotivation, however it is unknown whether mouse models of ASD represent this condition. Here we used two highly trusted ASD mouse models (male Shank3-deficient [Shank3+/ΔC ] mice modeling the monogenic etiology of ASD, and inbred BTBR mice [both male and female] modeling the idiopathic and highly polygenic pathology for ASD) to evaluate the level of motivation to engage in a social interaction. In the behavioral paradigms utilized, a social stimulus was placed in the open arm of the elevated plus maze (EPM), or the light compartment of the light-dark box (LDB). To engage in a social interaction, mice were thus required to endure innately aversive conditions (open areas, height, and/or light). In the modified EPM paradigm, both Shank3+/ΔC and BTBR mice demonstrated decreased open-arm engagement with a social stimulus but not a novel object, suggesting reduced incentive to engage in a social interaction in these models. However, these deficits were not expressed under the less severe aversive pressures of the LDB. Collectively, we show that ASD mouse models exhibit diminished social interaction incentive, and provide a new investigation strategy facilitating the study of the neurobiological mechanisms underlying social reward and motivation deficits in neuropsychiatric disorders.

Concise asymmetric synthesis of (-)-bilobalide.

The Ginkgo biloba metabolite bilobalide is widely ingested by humans but its effect on the mammalian central nervous system is not fully understood1-4. Antagonism of γ-aminobutyric acid A receptors (GABAARs) by bilobalide has been linked to the rescue of cognitive deficits in mouse models of Down syndrome5. A lack of convulsant activity coupled with neuroprotective effects have led some to postulate an alternative, unidentified target4; however, steric congestion and the instability of bilobalide1,2,6 have prevented pull-down of biological targets other than the GABAΑRs. A concise and flexible synthesis of bilobalide would facilitate the development of probes for the identification of potential new targets, analogues with differential selectivity between insect and human GABAΑRs, and stabilized analogues with an enhanced serum half-life7. Here we exploit the unusual reactivity of bilobalide to enable a late-stage deep oxidation that symmetrizes the molecular core and enables oxidation states to be embedded in the starting materials. The same overall strategy may be applicable to G. biloba congeners, including the ginkgolides-some of which are glycine-receptor-selective antagonists8. A chemical synthesis of bilobalide should facilitate the investigation of its biological effects and its therapeutic potential.

The Onset and Progression of Hippocampal Synaptic Plasticity Deficits in the Q175FDN Mouse Model of Huntington Disease.

Huntington disease (HD) is an inherited neurodegenerative disease characterized by a clinical triad of motor, psychiatric and cognitive symptoms. HD is caused by a CAG repeat expansion in the gene encoding the huntingtin protein. Homozygosity for the HD-causing mutation is extremely rare; thus, the majority of HD patients express the mutant huntingtin protein in addition to reduced levels of the non-pathogenic huntingtin protein. Deficits in synaptic plasticity, including hippocampal long-term potentiation (LTP), have been identified in various mouse models of HD and are thought to contribute to the debilitating cognitive symptoms associated with the disease. However, the bulk of these studies used N-terminal fragment or homozygous knock-in mouse models of HD at symptomatic ages, and our understanding of the onset and progression of synaptic plasticity deficits in the HD brain is lacking. To better understand the time-course of synaptic plasticity deficits in HD, as well as the impact of heterozygous and homozygous huntingtin mutations, we quantified basal synaptic connectivity, presynaptic release probability, presynaptically mediated post-tetanic potentiation (PTP) and postsynaptically mediated LTP at presymptomatic, early symptomatic and late symptomatic ages in heterozygous and homozygous Q175FDN knock-in HD mice. Our results demonstrate clear age-dependent effects of the HD-causing mutation on both short and long-term plasticity that generally emerge earlier in homozygous mice. Interestingly, deficits in presynaptic short-term plasticity were more closely linked to disease progression than deficits in postsynaptic LTP, and heterozygous mice were more susceptible to an LTP deficit when induced by high frequency stimulation compared to theta burst stimulation. To the best of our knowledge, the present study represents the most thorough characterization to date of the onset and progression of hippocampal synaptic plasticity deficits in a mouse model of HD, and should prove valuable to future studies exploring cellular mechanisms underlying the debilitating cognitive decline in HD.

Therapeutic potential and underlying mechanism of sarcosine (N-methylglycine) in N-methyl-D-aspartate (NMDA) receptor hypofunction models of schizophrenia.

Compelling animal and clinical studies support the N-methyl-D-aspartate receptor (NMDAR) hypofunction hypothesis of schizophrenia and suggest promising pharmacological agents to ameliorate negative and cognitive symptoms of schizophrenia, including sarcosine, a glycine transporter-1 inhibitor. It is imperative to evaluate the therapeutic potential of sarcosine in animal models, which provide indispensable tools for testing drug effects in detail and elucidating the underlying mechanisms. In this study, a series of seven experiments was conducted to investigate the effect of sarcosine in ameliorating behavioral deficits and the underlying mechanism in pharmacological (i.e., MK-801-induced) and genetic (i.e., serine racemase-null mutant (SR-/-) mice) NMDAR hypofunction models. In Experiment 1, the acute administration of 500/1000 mg/kg sarcosine (i.p.) had no adverse effects on motor function and serum biochemical responses. In Experiments 2-4, sarcosine significantly alleviated MK-801-induced (0.2 mg/kg) brain abnormalities and behavioral deficits in MK-801-induced and SR-/- mouse models. In Experiment 5, the injection of sarcosine enhanced CSF levels of glycine and serine in rat brain. In Experiments 6-7, we show for the first time that sarcosine facilitated NMDAR-mediated hippocampal field excitatory postsynaptic potentials and influenced the movement of surface NMDARs at extrasynaptic sites. Sarcosine effectively regulated the surface trafficking of NMDARs, NMDAR-evoked electrophysiological activity, brain glycine levels and MK-801-induced abnormalities in the brain, which contributed to the amelioration of behavioral deficits in mouse models of NMDAR hypofunction.

Tau is required for progressive synaptic and memory deficits in a transgenic mouse model of \u03b1-synucleinopathy

Parkinson’s disease dementia (PDD) and dementia with Lewy bodies (DLB) are clinically and neuropathologically highly related α-synucleinopathies that collectively constitute the second leading cause of neurodegenerative dementias. Genetic and neuropathological studies directly implicate α-synuclein (αS) abnormalities in PDD and DLB pathogenesis. However, it is currently unknown how αS abnormalities contribute to memory loss, particularly since forebrain neuronal loss in PDD and DLB is less severe than in Alzheimer’s disease. Previously, we found that familial Parkinson’s disease-linked human mutant A53T αS causes aberrant localization of the microtubule-associated protein tau to postsynaptic spines in neurons, leading to postsynaptic deficits. Thus, we directly tested if the synaptic and memory deficits in a mouse model of α-synucleinopathy (TgA53T) are mediated by tau. TgA53T mice exhibit progressive memory deficits associated with postsynaptic deficits in the absence of obvious neuropathological and neurodegenerative changes in the hippocampus. Significantly, removal of endogenous mouse tau expression in TgA53T mice (TgA53T/mTau−/−), achieved by mating TgA53T mice to mouse tau-knockout mice, completely ameliorates cognitive dysfunction and concurrent synaptic deficits without affecting αS expression or accumulation of selected toxic αS oligomers. Among the known tau-dependent effects, memory deficits in TgA53T mice were associated with hippocampal circuit remodeling linked to chronic network hyperexcitability. This remodeling was absent in TgA53T/mTau−/− mice, indicating that postsynaptic deficits, aberrant network hyperactivity, and memory deficits are mechanistically linked. Our results directly implicate tau as a mediator of specific human mutant A53T αS-mediated abnormalities related to deficits in hippocampal neurotransmission and suggest a mechanism for memory impairment that occurs as a consequence of synaptic dysfunction rather than synaptic or neuronal loss. We hypothesize that these initial synaptic deficits contribute to network hyperexcitability which, in turn, exacerbate cognitive dysfunction. Our results indicate that these synaptic changes present potential therapeutic targets for amelioration of memory deficits in α-synucleinopathies.

In vivo neuronal gene editing via CRISPR–Cas9 amphiphilic nanocomplexes alleviates deficits in mouse models of Alzheimer’s disease

In vivo gene editing in post-mitotic neurons of the adult brain may be a useful strategy for treating neurological diseases. Here, we develop CRISPR-Cas9 nanocomplexes and show they were effective in the adult mouse brain, with minimal off-target effects. Using this system to target Bace1 suppressed amyloid beta (Aβ)-associated pathologies and cognitive deficits in two mouse models of Alzheimer's disease. These results broaden the potential application of CRISPR-Cas9 systems to neurodegenerative diseases.

Modified Exosomes Reduce Apoptosis and Ameliorate Neural Deficits Induced by Traumatic Brain Injury.

Apoptosis contributes to the pathogenesis of traumatic brain injury (TBI). Engineered exosomes incorporated with therapeutic nuclear acids have been explored for gene therapy for human diseases. The current study sought to investigate the effect of modified exosome-containing plasmids expressing B-cell lymphoma-2 (Bcl-2) and Bcl-2-associated X-protein (Bax) short hairpin RNA (shRNA) on apoptosis and neural functions after TBI. C57BL/6J mice were subjected to controlled cortical impact injury and were treated with the modified exosomes. The results showed that modified exosomes attenuated the decrease of myeloid cell leukemia-1 (Mcl-1), X-linked inhibitor of apoptosis protein (XIAP), and Survivin protein levels in the brain and reduced Cytochrome c release from mitochondria to cytosol after TBI. They also attenuated the impairments of miniature excitatory postsynaptic current (mEPSC) and long-term potentiation (LTP) in the hippocampus of TBI mice and improved the motor and cognitive behaviors after TBI. These results suggested that the modified exosomes might reduce apoptosis and ameliorate neural and functional deficits in mouse models of TBI.

Effects of rapamycin on social interaction deficits and gene expression in mice exposed to valproic acid in utero

The mammalian target of rapamycin (mTOR) signaling pathway plays a crucial role in cell metabolism, growth, and proliferation. The overactivation of mTOR has been implicated in the pathogenesis of syndromic autism spectrum disorder (ASD), such as tuberous sclerosis complex (TSC). Treatment with the mTOR inhibitor rapamycin improved social interaction deficits in mouse models of TSC. Prenatal exposure to valproic acid (VPA) increases the incidence of ASD. Rodent pups that are exposed to VPA in utero have been used as an animal model of ASD. Activation of the mTOR signaling pathway was recently observed in rodents that were exposed to VPA in utero, and rapamycin ameliorated social interaction deficits. The present study investigated the effect of rapamycin on social interaction deficits in both adolescence and adulthood, and gene expressions in mice that were exposed to VPA in utero. We subcutaneously injected 600 mg/kg VPA in pregnant mice on gestational day 12.5 and used the pups as a model of ASD. The pups were intraperitoneally injected with rapamycin or an equal volume of vehicle once daily for 2 consecutive days. The social interaction test was conducted in the offspring after the last rapamycin administration at 5–6 weeks of ages (adolescence) or 10–11 weeks of age (adulthood). Whole brains were collected after the social interaction test in the adulthood, and microarray and Western blot analyses were performed. Mice that were exposed to VPA and treated with vehicle exhibited a decrease in social interaction compared with control mice that were treated with vehicle. Rapamycin treatment in VPA-exposed mice improved social deficits. Mice that were exposed to VPA and treated with vehicle exhibited the aberrant expression of genes in the mTOR signaling pathway, and rapamycin treatment recovered changes in the expression of some genes, including Fyb and A330094K24Rik. Rapamycin treatment suppressed S6 phosphorylation in VPA-exposed mice. Aberrant gene expression was associated with social interaction deficits in VPA-exposed mice. Rapamycin may be an effective treatment for non-syndromic ASD in adolescent and adult patients who present impairments in the mTOR signaling pathway.

On the Design of Broad-Based Neuropsychological Test Batteries to Assess the Cognitive Abilities of Individuals with Down Syndrome in the Context of Clinical Trials.

Down syndrome (DS) is the most common genetically-defined cause of intellectual disability. Neurodevelopmental deficits displayed by individuals with DS are generally global, however, disproportionate deficits in cognitive processes that depend heavily on the hippocampus and prefrontal cortex are also well documented. Additionally, DS is associated with relative strengths in visual processing and visuospatial short-term memory, and weaknesses in the verbal domain. Although reports of pharmacological rescuing of learning and memory deficits in mouse models of DS abound in the literature, proving the principle that cognitive ability of persons with DS can be boosted through pharmacological means is still an elusive goal. The design of customized batteries of neuropsychological efficacy outcome measures is essential for the successful implementation of clinical trials of potential cognitive enhancing strategies. Here, we review the neurocognitive phenotype of individuals with DS and major broad-based test batteries designed to quantify specific cognitive domains in these individuals, including the one used in a pilot trial of the drug memantine. The main goal is to illustrate the essential considerations in planning trials to enhance cognitive functions in individuals with DS, which should also have implications for the design of similar studies in individuals with other forms of intellectual disability.

Anle138b modulates α-synuclein oligomerization and prevents motor decline and neurodegeneration in a mouse model of multiple system atrophy.

ABSTRACTBackgroundMSA is a fatal neurodegenerative disease characterized by autonomic failure and severe motor impairment. Its main pathological hallmark is the accumulation of α‐synuclein in oligodendrocytes, leading to glial and neuronal dysfunction and neurodegeneration. These features are recapitulated in the PLP‐hαSyn mouse model expressing human α‐synuclein in oligodendrocytes. At present, there is no effective disease‐modifying therapy. Previous experiments have shown that the aggregation inhibitor, anle138b, reduces neurodegeneration and behavioral deficits in mouse models of other proteinopathies.ObjectivesTo test the therapeutic potential of anle138b in a mouse model of MSA.MethodsTwo‐month‐old PLP‐hαSyn mice were fed over a period of 4 months with pellets containing anle138b at two different doses (0.6 and 2 g/kg) and compared to healthy controls and PLP‐hαSyn mice fed with placebo pellets. At the end of the treatment, behavioral and histological analyses were performed.ResultsWe observed a reversal of motor function to healthy control levels when PLP‐hαSyn mice were treated with both doses of anle138b. Histological and molecular analyses showed a significant reduction in α‐synuclein oligomers and glial cytoplasmic inclusions in animals fed with anle138b compared to nontreated mice. These animals also present preservation of dopaminergic neurons and reduction in microglial activation in SN correlating with the α‐synuclein reduction observed.ConclusionsAnle138b reduces α‐synuclein accumulation in PLP‐hαSyn mice, leading to neuroprotection, reduction of microglial activation, and preservation of motor function supporting the use of anle138b in a future clinical trial for MSA. © 2018 The Authors. Movement Disorders published by Wiley Periodicals, Inc. on behalf of International Parkinson and Movement Disorder Society.

Pleiotropic Benefits of the Angiotensin Receptor Blocker Candesartan in a Mouse Model of Alzheimer Disease.

The angiotensin receptor blocker losartan mitigated cerebrovascular and cognitive deficits in mouse models of Alzheimer disease, in line with some clinical evidence of reduced onset and progression to Alzheimer disease. We investigated whether these benefits apply to another angiotensin receptor blocker, namely candesartan. Adult transgenic mice overexpressing a mutated form of the human APP (amyloid precursor protein) and wild-type controls were treated with vehicle or candesartan (cohort 1: 2 months, 1 mg/kg per day, osmotic subcutaneous minipumps; cohort 2: 5 months, 10 mg/kg per day in drinking water). Candesartan largely restored endothelial and smooth muscle function and reduced neuroinflammation in both cohorts, without improving sensory evoked cerebral blood flow responses. Candesartan exerted restorative effects on the reduced number of Ki67-immunopositive proliferating cells in the granule cell layer of the hippocampus but not on that of DCX (doublecortin)-positive immature granule cells, despite normalizing the length of their dendritic projections in the molecular layer. Amyloid plaque load and impaired cognitive function were unaltered by candesartan, and blood pressure was decreased in treated APP and wild-type mice. Overall, findings show that candesartan shared several advantages reported previously for losartan, but it exhibited limited cognitive benefits and stronger blood pressure lowering effects. The choice of angiotensin receptor blocker may thus be critical for therapeutic efficacy in patients with vascular diseases at high risk of developing Alzheimer disease.

Modulation of astrocyte reactivity improves functional deficits in mouse models of Alzheimer\u2019s disease

Astrocyte reactivity and neuroinflammation are hallmarks of CNS pathological conditions such as Alzheimer’s disease. However, the specific role of reactive astrocytes is still debated. This controversy may stem from the fact that most strategies used to modulate astrocyte reactivity and explore its contribution to disease outcomes have only limited specificity. Moreover, reactive astrocytes are now emerging as heterogeneous cells and all types of astrocyte reactivity may not be controlled efficiently by such strategies.Here, we used cell type-specific approaches in vivo and identified the JAK2-STAT3 pathway, as necessary and sufficient for the induction and maintenance of astrocyte reactivity. Modulation of this cascade by viral gene transfer in mouse astrocytes efficiently controlled several morphological and molecular features of reactivity. Inhibition of this pathway in mouse models of Alzheimer’s disease improved three key pathological hallmarks by reducing amyloid deposition, improving spatial learning and restoring synaptic deficits.In conclusion, the JAK2-STAT3 cascade operates as a master regulator of astrocyte reactivity in vivo. Its inhibition offers new therapeutic opportunities for Alzheimer’s disease.

Correction of cognitive deficits in mouse models of Down syndrome by a pharmacological inhibitor of DYRK1A.

ABSTRACTGrowing evidence supports the implication of DYRK1A in the development of cognitive deficits seen in Down syndrome (DS) and Alzheimer's disease (AD). We here demonstrate that pharmacological inhibition of brain DYRK1A is able to correct recognition memory deficits in three DS mouse models with increasing genetic complexity [Tg(Dyrk1a), Ts65Dn, Dp1Yey], all expressing an extra copy of Dyrk1a. Overexpressed DYRK1A accumulates in the cytoplasm and at the synapse. Treatment of the three DS models with the pharmacological DYRK1A inhibitor leucettine L41 leads to normalization of DYRK1A activity and corrects the novel object cognitive impairment observed in these models. Brain functional magnetic resonance imaging reveals that this cognitive improvement is paralleled by functional connectivity remodelling of core brain areas involved in learning/memory processes. The impact of Dyrk1a trisomy and L41 treatment on brain phosphoproteins was investigated by a quantitative phosphoproteomics method, revealing the implication of synaptic (synapsin 1) and cytoskeletal components involved in synaptic response and axonal organization. These results encourage the development of DYRK1A inhibitors as drug candidates to treat cognitive deficits associated with DS and AD.

Intravenously Administered Iduronate-2-Sulfatase Fused with Anti-Human Transferrin Receptor Antibody (Jr-141) Crosses the Blood-Brain Barrier to Address Central Nervous System Disorders in Hunter Syndrome: A Randomised, Open-Label, Phase 1/2 Trial

Background: Hunter syndrome (mucopolysaccharidosis II, MPS II) is an X-linked recessive lysosomal storage disease in which a deficiency of iduronate-2-sulfatase causes an accumulation of glycosaminoglycans, giving rise to multiple systemic as well as central nervous system (CNS) symptoms. The currently available enzyme replacement therapy with idursulfase is ineffective against the associated CNS symptoms, because the blood-brain barrier (BBB) prevents the enzyme from reaching the brain. A novel iduronate-2-sulfatase fused with anti-human transferrin receptor antibody (JR-141) has been shown to penetrate the BBB and ameliorate learning deficits in model mice. This first-in-human translational study evaluated the pharmacokinetics, safety and efficacy of JR-141 in patients with MPS II. Methods: In this phase 1/2 multicentre, open-label, randomised clinical trial, 15 patients with MPS II who were being treated with intravenous idursulfase were recruited in Japan, and treatment was switched to intravenous administration of JR-141. In Part 1 of the study, which was designed to evaluate the safety of JR-141, the dosage was escalated over a period of 4 weeks (from 0.01 to 2.0 mg/kg/week); in Part 2, a 4-week randomised evaluation of the pharmacokinetics, safety and exploratory efficacy of JR-141 (at 1.0 or 2.0 mg/kg/week) was made. Cerebrospinal fluid (CSF) concentrations of heparan sulfate (HS) and dermatan sulfate (DS) were compared at the start of JR-141 administration and after 3 weeks, and plasma and urine concentrations of HS and DS were compared at the start and after 4 weeks. Findings: Between 10th May, 2017 and 25th October, 2017, we recruited a total of 15 male patients from 9 investigational sites in Japan. Of these, 14 were enrolled after 1 was excluded as unsuitable. Two patients without intellectual disabilities were selected for the dose escalation study (Part 1) and were given 0*01, 0*1, 1.0, and 2*0 mg/kg/week of JR-141 intravenously; plasma concentrations of JR-141 were dose-dependent and peaked at 3 h after initiation of each infusion. One patient developed erythema and pyrexia, which abated quickly, and the other exhibited no adverse reactions. In Part 2, the remaining 12 patients were randomly allocated to JR-141 dosing groups of 1*0 or 2*0 mg/kg/week. The plasma concentration profiles of JR-141 did not differ between the first and final administration, indicating no drug accumulation. Plasma and urinary levels of HS and DS were both suppressed by JR-141, and HS concentrations in the CSF had significantly decreased after the last administration (by an average of 25*1% in patients taking 1*0 mg/kg/week, and 31*5% in those taking 2*0 mg/kg/week). Two patients showed some amelioration of neurocognitive and motor symptoms following the 4-week treatment. No drug-related serious adverse events were observed during the study period. Interpretation: Patients with Hunter syndrome who were treated with JR-141 showed significant reductions in neurotoxin levels in the CSF, suggesting the drug successfully penetrated the BBB. Furthermore, JR-141 was no less effective in treating systemic symptoms than conventional enzyme replacement therapy with idursulfase. If JR-141 reduces glycosaminoglycan accumulation in the CSF, it should also be effective in treating CNS symptoms. This will be investigated in future clinical trials. Clinical Trial Number: NCT03128593 Funding Statement: The trial was funded by JCR Pharmaceuticals. Declaration of Interests: Torayuki Okuyama reports research grants from Sanofi, JCR Pharmaceuticals, GC Pharma, Dainippon Sumitomo Pharma, Actelion, Alexion and Anges, along with honoraria from Sanofi, Dainippon Sumitomo Pharma, Actelion and Anges. Yoshikatsu Eto has conducted consultancy for JCR Pharmaceuticals, and he has been awarded grants and research support from Actelion, BioMarin Pharmaceutical Inc. and Sanofi; he has also received honoraria from Actelion, BioMarin Pharmaceutical Inc., Sanofi, Shire and Dainippon Sumitomo Pharma. Norio Sakai has conducted consultancy for JCR Pharmaceuticals, and he has been awarded grant/research support from Sanofi and Dainippon Sumitomo Pharma, and honoraria from Actelion, BioMarin Pharmaceutical Inc., Sanofi, Shire and Dainippon Sumitomo Pharma. Ethics Approval Statement: The study was conducted in 8 hospitals and specialised MPS centres in Japan, and was in compliance with the Declaration of Helsinki. The protocol and patient informed consent were reviewed and approved by the Institutional Review Board at each participating institution.

Beneficial Effect of a Selective Adenosine A2A Receptor Antagonist in the APPswe/PS1dE9 Mouse Model of Alzheimer's Disease.

Consumption of caffeine, a non-selective adenosine A2A receptor (A2AR) antagonist, reduces the risk of developing Alzheimer’s disease (AD) and mitigates both amyloid and Tau lesions in transgenic mouse models of the disease. While short-term treatment with A2AR antagonists have been shown to alleviate cognitive deficits in mouse models of amyloidogenesis, impact of a chronic and long-term treatment on the development of amyloid burden, associated neuroinflammation and memory deficits has never been assessed. In the present study, we have evaluated the effect of a 6-month treatment of APPsw/PS1dE9 mice with the potent and selective A2AR antagonist MSX-3 from 3 to 9-10 months of age. At completion of the treatment, we found that the MSX-3 treatment prevented the development of memory deficits in APP/PS1dE9 mice, without significantly altering hippocampal and cortical gene expressions. Interestingly, MSX-3 treatment led to a significant decrease of Aβ1-42 levels in the cortex of APP/PS1dE9 animals, while Aβ1-40 increased, thereby strongly affecting the Aβ1-42/Aβ1-40 ratio. Together, these data support the idea that A2AR blockade is of therapeutic value for AD.

Gait Analysis of Age-dependent Motor Impairments in Mice with Neurodegeneration.

Motor behavior tests are commonly used to determine the functional relevance of a rodent model and to test newly developed treatments in these animals. Specifically, gait analysis allows recapturing disease relevant phenotypes that are observed in human patients, especially in neurodegenerative diseases that affect motor abilities such as Parkinson's disease (PD), Alzheimer's disease (AD), amyotrophic lateral sclerosis (ALS), and others. In early studies along this line, the measurement of gait parameters was laborious and depended on factors that were hard to control (e.g., running speed, continuous running). The development of ventral plane imaging (VPI) systems made it feasible to perform gait analysis at a large scale, making this method a useful tool for the assessment of motor behavior in rodents. Here, we present an in-depth protocol of how to use kinematic gait analysis to examine the age-dependent progression of motor deficits in mouse models of neurodegeneration; mouse lines with decreased levels of endophilin, in which neurodegenerative damage progressively increases with age, are used as an example.

Elevated levels of brain homocysteine directly modulate the pathological phenotype of a mouse model of tauopathy.

High circulating level of homocysteine (Hcy), also known as hyper-homocysteinemia, is a risk factor for Alzheimer’s disease (AD). Previous studies showed that elevated Hcy promotes brain amyloidosis and behavioral deficits in mouse models of AD. However, whether it also directly modulates the development of tau neuropathology independently of amyloid-beta in vivo is unknown. Herein we investigate the effect of diet-induced elevated levels of brain Hcy on the phenotype of a relevant mouse model of human tauopathy. Compared with controls, tau mice fed low folate and B vitamins diet, had a significant increase in brain Hcy levels and worsening of behavioral deficits. The same mice had a significant elevation of tau phosphorylation, synaptic pathology and astrocytes activation. In vitro studies demonstrated that Hcy effect on tau phosphorylation was mediated by an upregulation of the 5-lipoxygenase via cdk5 kinase pathway activation. Our findings support the novel concept that high Hcy levels in the central nervous system is a metabolic risk factor also for neurodegenerative diseases specifically characterized by the progressive accumulation of tau pathology, namely tauopathies.

High channel count microphone array accurately and precisely localizes ultrasonic signals from freely-moving mice

BackgroundAn integral component in the assessment of vocal behavior in groups of freely interacting animals is the ability to determine which animal is producing each vocal signal. This process is facilitated by using microphone arrays with multiple channels. New method and comparison with existing methodsHere, we made important refinements to a state-of-the-art microphone array based system used to localize vocal signals produced by freely interacting laboratory mice. Key changes to the system included increasing the number of microphones as well as refining the methodology for localizing and assigning vocal signals to individual mice. ResultsWe systematically demonstrate that the improvements in the methodology for localizing mouse vocal signals led to an increase in the number of signals detected as well as the number of signals accurately assigned to an animal. ConclusionsThese changes facilitated the acquisition of larger and more comprehensive data sets that better represent the vocal activity within an experiment. Furthermore, this system will allow more thorough analyses of the role that vocal signals play in social communication. We expect that such advances will broaden our understanding of social communication deficits in mouse models of neurological disorders.

Association Among Gut Microbes, Intestinal Physiology, and Autism

Autism spectrum disorder (ASD) is a set of neurodevelopmental disorders characterized by two core symptoms: social deficits and increase in stereotypic/repetitive behaviors. Along with the core symptoms of ASD, other comorbid conditions can be observed in certain populations of people with ASD, such as gastrointestinal (GI) complications and altered gut microbiome (Adams et al., 2011 ; Parracho et al., 2005). Homeostasis of the GI system is closely regulated by the gut microbiota. Therefore, whether the gut microbiota is a contributing factor for ASD has been postulated recently. Several key questions have been raised. Do gut microbes contribute to the behavioral symptoms in ASD? How do gut microbes affect behavioral output through the gut–brain axis? How do gut and brain communicate with each other? Due to the complexity of the distal connection between gut and brain, these are the key questions that remain unanswered in the field.