Larger cages with housing unit environment enrichment improve the welfare of marmosets.

The provision of adequate space for laboratory animals is essential not only for good welfare but accurate studies. For example, housing conditions for primates used in biomedical research may negatively affect welfare and thus the reliability of findings. In common marmosets (Callithrix jacchus), an appropriate cage size enables a socially harmonious family environment and optimizes reproductive potential.

Adaptive responses to alloxan-induced mild oxidative stress ameliorate certain tauopathy phenotypes.

Oxidative stress is considered to promote aging and age-related disorders such as tauopathy. Although recent reports suggest that oxidative stress under certain conditions possesses anti-aging properties, no such conditions have been reported to ameliorate protein-misfolding diseases. Here, we used neuronal and murine models that overexpress human tau to demonstrate that mild oxidative stress generated by alloxan suppresses several phenotypes of tauopathy.

Differential regional distribution of phosphorylated tau and synapse loss in the nucleus accumbens in tauopathy model mice.

Tauopathies differ in terms of the brain regions that are affected. In Alzheimer's disease, basal forebrain and hippocampus are mainly involved, while frontotemporal lobar degeneration affects the frontal and temporal lobes and subcortical nuclei including striatum. Over 90% of human cases of tauopathies are sporadic, although the majority of established tau-transgenic mice have had mutations.

Aggregation of detergent-insoluble tau is involved in neuronal loss but not in synaptic loss.

Neurofibrillary tangles (NFTs), which consist of highly phosphorylated tau, are hallmarks of neurodegenerative diseases including Alzheimer disease (AD). In neurodegenerative diseases, neuronal dysfunction due to neuronal loss and synaptic loss accompanies NFT formation, suggesting that a process associated with NFT formation may be involved in neuronal dysfunction. To clarify the relationship between the tau aggregation process and synapse and neuronal loss, we compared two lines of mice expressing human tau with or without an aggregation-prone P301L mutation.

GSK-3beta is required for memory reconsolidation in adult brain.

Activation of GSK-3beta is presumed to be involved in various neurodegenerative diseases, including Alzheimer's disease (AD), which is characterized by memory disturbances during early stages of the disease. The normal function of GSK-3beta in adult brain is not well understood. Here, we analyzed the ability of heterozygote GSK-3beta knockout (GSK+/-) mice to form memories.

GABA(A) receptor-mediated acceleration of aging-associated memory decline in APP/PS1 mice and its pharmacological treatment by picrotoxin.

Advanced age and mutations in the genes encoding amyloid precursor protein (APP) and presenilin (PS1) are two serious risk factors for Alzheimer's disease (AD). Finding common pathogenic changes originating from these risks may lead to a new therapeutic strategy. We observed a decline in memory performance and reduction in hippocampal long-term potentiation (LTP) in both mature adult (9-15 months) transgenic APP/PS1 mice and old (19-25 months) non-transgenic (nonTg) mice.

Hyperphosphorylated tau in parahippocampal cortex impairs place learning in aged mice expressing wild-type human tau.

To investigate how tau affects neuronal function during neurofibrillary tangle (NFT) formation, we examined the behavior, neural activity, and neuropathology of mice expressing wild-type human tau. Here, we demonstrate that aged (>20 months old) mice display impaired place learning and memory, even though they do not form NFTs or display neuronal loss. However, soluble hyperphosphorylated tau and synapse loss were found in the same regions.

Expression analysis of actin-related genes as an underlying mechanism for mood disorders.

In this study, we explored the newly postulated 'disturbed cytoskeletal' theory of mood disorders. Firstly, we identified Cap1, a gene for important mediator of actin turnover, as a cogent quantitative trait gene for depressive trait of mice by combining the results of our prior genetic and current genome-wide expression analyses. Then we rigorously examined 'core' actin-related gene expression in the frontal cortex of C57BL/6 (B6) (prone to depression) and C3H/He (C3) (resistant to depression) mice.