PKN1 promotes synapse maturation by inhibiting mGluR-dependent silencing through neuronal glutamate transporter activation.

Abnormal metabotropic glutamate receptor (mGluR) activity could cause brain disorders; however, its regulation has not yet been fully understood. Here, we report that protein kinase N1 (PKN1), a protein kinase expressed predominantly in neurons in the brain, normalizes group 1 mGluR function by upregulating a neuronal glutamate transporter, excitatory amino acid transporter 3 (EAAT3), and supports silent synapse activation. Knocking out PKN1a, the dominant PKN1 subtype in the brain, unmasked abnormal input-nonspecific mGluR-dependent long-term depression (mGluR-LTD) and AMPA receptor (AMPAR) silencing in the developing hippocampus. mGluR-LTD was mimicked by inhibiting glutamate transporters in wild-type mice. Knocking out PKN1a decreased hippocampal EAAT3 expression and PKN1 inhibition reduced glutamate uptake through EAAT3. Also, synaptic transmission was immature; there were more silent synapses and fewer spines with shorter postsynaptic densities in PKN1a knockout mice than in wild-type mice. Thus, PKN1 plays a critical role in regulation of synaptic maturation by upregulating EAAT3 expression.

Admission of people with dementia to psychiatric hospitals in Japan: factors that can shorten their hospitalizations.

AIM: People exhibiting serious behavioural and psychological symptoms of dementia are usually voluntarily or involuntarily committed to psychiatric hospitals for treatment. In Japan, the average hospital stay for individuals with dementia is about 2 years. Ideally, individuals should be discharged once their symptoms have subsided. However, we see cases in Japan where individuals remain institutionalized long after behavioural and psychological symptoms of dementia are no longer apparent. This study will attempt to identify factors contributing to shorter stays in psychiatric hospitals for dementia patients. METHODS: Questionnaires consisting of 17 items were mailed to 121 psychiatric hospitals with dementia treatment wards in western Japan. RESULTS: Out of 121 hospitals that received the questionnaires, 45 hospitals returned them. The total number of new patient admissions at all 45 hospitals during the month of August 2014 was 1428, including 384 dementia patients (26.9%). The average length of stay in the dementia wards in August 2014 was 482.7 days. Our findings revealed that the rate of discharge after 2 months was 35.4% for the dementia wards. In addition, we found that the average stay in hospitals charging or planning to charge the rehabilitation fee to dementia patients was significantly shorter than in hospitals not charging the rehabilitation fee. CONCLUSION: In Japan, dementia patients account for over 25% of new admissions to psychiatric hospitals with dementia wards. The average length of stay in a psychiatric hospital dementia ward is more than 1 year. A discharge after fewer than 2 months is exceedingly rare for those in a dementia ward compared with dementia patients in other wards. If institutions focus on rehabilitation, it may be possible to shorten the stay of dementia patients in psychiatric hospitals.

S6 kinase phosphorylated at T229 is involved in tau and actin pathologies in Alzheimer's disease.

The 70-kDa ribosomal protein S6 kinase (S6K), a serine/threonine kinase that modulates the phosphorylation of the 40S ribosomal protein S6, regulates cell cycle progression and is known as a tau kinase in Alzheimer's disease (AD). In AD brains, neurofibrillary tangles (NFTs) have been shown to be positively stained with antibodies against S6K proteins phosphorylated at T389 (pT389-S6K) or T421/S424 (pT421/S424-S6K) by the mammalian target of rapamycin and mitogen-activated protein kinase pathways, respectively. However, there is little information available about S6K proteins directly phosphorylated at T229 (pT229-S6K) by the PI3K-PDK1 pathway. In the present study, we investigated the distribution of pT229-S6K in post mortem human brain tissues from elderly (control) and patients with AD using immnunoblotting and immunohistochemistry. pT229-S6K immunoreactivity was localized to small granular structures in neurons and endothelial cells in control and AD brains. In AD brains, intense pT229-S6K immunoreactivity was detected in 16.3% of AT8-positive NFTs, neuropil threads, and dystrophic neurites in the hippocampus and other vulnerable brain areas. In addition, Hirano bodies were also positive for pT229-S6K but were negative for pT389-S6K or pT421/S424-S6K. The present results indicate that S6K phosphorylation via the PI3K-PD1 pathway is involved in tau pathology in NFTs and abnormal neurites as well as actin pathology in Hirano bodies.

Action observation with kinesthetic illusion can produce human motor plasticity.

After watching sports, people often feel as if their sports skills might have been improved, even without any actual training. On some occasions, this motor skill learning through observation actually occurs. This phenomenon may be due to the fact that both action and action observation (AO) can activate shared cortical areas. However, the neural basis of performance gain through AO has not yet been fully clarified. In the present study, we used transcranial magnetic stimulation to investigate whether primary motor cortex (M1) plasticity is a physiological substrate of AO-induced performance gain and whether AO itself is sufficient to change motor performance. The excitability of M1, especially that of its intracortical excitatory circuit, was enhanced after and during AO with kinesthetic illusion but not in interventions without this illusion. Moreover, behavioral improvement occurred only after AO with kinesthetic illusion, and a significant correlation existed between the performance gain and the degree of illusion. Our findings indicated that kinesthetic illusion is an essential component of the motor learning and M1 plasticity induced by AO, and this insight may be useful for the strategic rehabilitation of stroke patients.

[Survey for management of BPSD in care managers and special psychiatric wards for people with severe dementia].

OBJECTIVES: The integration of medical care and long-term care services is very important in managing dementia patients. We performed two surveys to explore how dementia patients and their symptoms were managed in care facilities (study 1) and at special psychiatric wards for people with severe dementia (study 2). METHODS: (Study 1) One hundred and sixty-six care managers were subjects for the survey. The questionnaires were distributed at the meeting and recovered at the same meeting place. (Study 2) The questionnaires were sent by mail to 405 psychiatric hospitals with special psychiatric wards. The questionnaires were recovered from 105 wards (recovery rate: 26.0%). RESULTS: (Study 1) Over 60% of people the care managers take care of have dementia, and 1/3 of them showed severe dementia. The care managers felt that it is very difficult to manage dementia patients with severe BPSD. They were of the opinion that psychiatric care should be administered to those people. (Study 2) The average period of stay on the wards was about 2 years. One third of people stayed on the wards for over 3 years. The reasons why the people have to stay longer on the wards were as follows: severe BPSD, limited number of care facilities for patients to go to after discharge from the wards, and patients' families do not accept them in their homes. CONCLUSIONS: Care managers supposed that dementia patients with severe BPSD should be managed by specialists in dementia, psychiatrists, etc., at psychiatric hospitals. Patients on special psychiatric wards stayed for longer because of a limited number of care facilities which can manage them.

Mirror visual feedback can induce motor learning in patients with callosal disconnection.

Mirror therapy using mirror visual feedback (MVF) has been applied to the stroke rehabilitation of hemiparesis. One possible mechanism of mirror therapy is the functional interhemispheric connectivity between sensorimotor areas via corpus callosum. To test this hypothesis, we investigated the MVF-induced motor learning in 2 patients with callosal disconnection. Callosal connection in patients was evaluated by clinical measures and the interhemispheric inhibition (IHI) using transcranial magnetic stimulation. Both patients suffered from somatosensory cognitive disconnection, and one showed the loss of IHI. Motor training with MVF significantly improved the motor behavior of both patients. Extending our previous study, the results of callosal patients suggested that the visual feedback through a mirror might play the crucial important role for the improvement of motor performance, rather than interhemispheric interaction via corpus callosum.

Kendrin is a novel substrate for separase involved in the licensing of centriole duplication.

The centrosome, consisting of a pair of centrioles surrounded by pericentriolar material, directs the formation of bipolar spindles during mitosis. Aberrant centrosome number can promote chromosome instability, which is implicated in tumorigenesis. Thus, centrosome duplication needs to be tightly regulated to occur only once per cell cycle. Separase, a cysteine protease that triggers sister chromatid separation, is involved in centriole disengagement, which licenses centrosomes for the next round of duplication. However, at least two questions remain unsolved: what is the substrate relevant to the disengagement, and how does separase, activated at anaphase onset, act on the disengagement that occurs during late mitosis. Here, we show that kendrin, also named pericentrin, is cleaved by activated separase at a consensus site in vivo and in vitro, and this leads to the delayed release of kendrin from the centrosome later in mitosis. Furthermore, we demonstrate that expression of a noncleavable kendrin mutant suppresses centriole disengagement and subsequent centriole duplication. Based on these results, we propose that kendrin is a novel and crucial substrate for separase at the centrosome, protecting the engaged centrioles from premature disengagement and thereby blocking reduplication until the cell passes through mitosis.

Human motor plasticity induced by mirror visual feedback.

The clinical use of mirror visual feedback (MVF) was initially introduced to alleviate phantom pain, and has since been applied to the improvement of hemiparesis following stroke. However, it is not known whether MVF can restore motor function by producing plastic changes in the human primary motor cortex (M1). Here, we used transcranial magnetic stimulation to test whether M1 plasticity is a physiological substrate of MVF-induced motor behavioral improvement. MVF intervention in normal volunteers using a mirror box improved motor behavior and enhanced excitatory functions of the M1. Moreover, behavioral and physiological measures of MVF-induced changes were positively correlated with each other. Improved motor performance occurred after observation of a simple action, but not after repetitive motor training of the nontarget hand without MVF, suggesting the crucial importance of visual feedback. The beneficial effects of MVF were disrupted by continuous theta burst stimulation (cTBS) over the M1, but not the control site in the occipital cortex. However, MVF following cTBS could further improve the motor functions. Our findings indicate that M1 plasticity, especially in its excitatory connections, is an essential component of MVF-based therapies.

Effect of perceptual learning on motor skills of hands: a functional magnetic resonance imaging study.

Our aim was to clarify the mechanism by which perceptual learning improves motor skills of hands. We included 18 healthy volunteers (age 21.3 ± 0.3 years, mean ± standard deviation) in the study with a crossover design. The subjects were randomly classified into 3 groups, and they performed a 2-ball quick rotation task with a hand. The role of perceptual learning in improving the ability to discern the length of a wooden stick held between the left thumb and index finger was studied between the first and second sessions of the task in group A, and between the second and third sessions in groups B and C with a period of rest interval between the first and second sessions. Functional magnetic resonance imaging (fMRI) was performed for each group during the perceptual learning session. The effect of intervention, in the form of perceptual learning, on the task performance was significantly greater than that of non-intervention in all subjects (p = 0.022). Among all the activated brain areas, the bilateral prefrontal cortices, right premotor area, right supplementary motor area, right primary sensory area, right primary motor area, right inferior parietal lobe, right thalamus, and left cerebellar posterior lobe showed positive correlations between the respective contrasts from the single-subject analysis and the behavioral data before and after the interventions (p < 0.001). This result indicates a pivotal role of the frontoparietal or frontocerebellar circuits in sensorimotor integration; a specific approach that activates these circuits should be developed for clinical rehabilitation of patients.

Parkinsonian Symptomatology May Correlate with CT Findings before and after Shunting in Idiopathic Normal Pressure Hydrocephalus.

We aimed to investigate the characteristics of Parkinsonian features assessed by the unified Parkinson's disease rating scale (UPDRS) and determine their correlations with the computed tomography (CT) findings in patients with idiopathic normal pressure hydrocephalus (iNPH). The total score and the scores for arising from chair, gait, postural stability, and body hypokinesia in the motor examination section of UPDRS were significantly improved after shunt operations. Stepwise multiple regression analysis revealed that postural stability was the determinant of the gait domain score of the iNPH grading scale. The canonical correlation analysis between the CT findings and the shunt-responsive Parkinsonian features indicated that Evans index rather than midbrain diameters had a large influence on the postural stability. Thus, the pathophysiology of postural instability as a cardinal feature of gait disturbance may be associated with impaired frontal projections close to the frontal horns of the lateral ventricles in the iNPH patients.

Accumulation of tumor-suppressor PTEN in Alzheimer neurofibrillary tangles.

The phosphatase and tensin homologue deleted on chromosome 10 (PTEN) negatively regulates intracellular levels of PIP3 and antagonizes the PI3K signaling pathway important for cell survival. The present study determined whether altered distribution of PTEN occurs in Alzheimer's disease (AD) brains. We investigated a possible role for PTEN in postmortem brain tissues from elderly controls and patients with AD using immunoblotting and microscopic analyses. Intense immunolabeling was found in the large neurons such as pyramidal cells. In normal neurons, PTEN was located in the nucleus, the cytoplasm of cell bodies and the proximal portion of apical dendrites. Reduced expression and redistribution of PTEN was seen in the remaining neurons in AD. In addition, PTEN was redistributed in damaged neurons from the nucleus and cytoplasm to neuritic pathology such as intracellular neurofibrillary tangles (NFTs), neuropil threads and dystrophic neurites within senile plaques in AD hippocampus, subiculum, entorhinal cortex and angular gyrus. Furthermore, double immunofluorescence staining showed dual labeling of intracellular NFTs for PTEN and tau, labeling of some axons for PTEN and phosphorylated neurofilament, and weak labeling of a few reactive astrocytes around senile plaques for PTEN and GFAP. Double labeling of NFTs was observed in a subset of tangle-bearing neurons either for PTEN and GSK3beta or for PTEN and MEK. Thus our results suggest that PTEN delocalized from the nucleus to the cytoplasm and to intracellular NFTs may cause a deregulation of PI3K pathway in the cytoplasm and may induce the nuclear dysfunction of PTEN in AD degenerating neurons.

A peptidyl-prolyl isomerase, FKBP12, accumulates in Alzheimer neurofibrillary tangles.

We investigated a possible role in Alzheimer's disease (AD) for FKBP12, a peptidyl-prolyl cis-trans isomerase known to be important in protein assembly, folding and transportation by using Western blotting and microscopic analyses in postmortem brain tissues from elderly controls and the patients with AD. FKBP12 was enriched and localized to neuronal cell bodies and neurites in control brains. Intense immunoreactivity was found in large neurons such as pyramidal cells. Many FKBP12 positive granules were located in the cytoplasm and the proximal portion of dendrites and axons, and in the nuclei. By contrast, the expression of FKBP12 in AD brains was lower than in control brains. Furthermore, numerous intracellular neurofibrillary tangles (NFTs) were stained for FKBP12 in the hippocampal CA1 subfield, subiculum, entorhinal cortex and angular gyrus. Neuritic pathology such as neuropil threads and dystrophic neurites (DNs) within senile plaques (SPs) and some reactive astrocytes were also immunolabeled for FKBP12 in AD. Double immunofluorescence staining showed dual labeling of intracellular NFTs for FKBP12 and tau. Similar results were obtained in reactive astrocytes for the combination of FKBP12 and glial fibrillary acidic protein (GFAP). Labeling for FKBP12 was dense in axons stained for highly phosphorylated neurofilament protein. Thus our results suggest that FKBP12 may be involved in neuronal or astrocytic cytoskeletal organization and in the abnormal metabolism of tau protein in AD damaged neurons.

The effects of visual, auditory, and mixed cues on choice reaction in Parkinson's disease.

We investigated the effects of visual, auditory, and mixed cues on complex choice reaction in people with Parkinson's disease (PD). The paradigm using a computerized task was based on a game, "paper-rock-scissors." Four types of sensory cues were employed: simple visual cues, auditory cues, visual cues with auditory distracters, and auditory cues with visual distracters. Subjects were instructed to win, draw, or even lose the games and were required to respond as soon as possible after the sensory cues. When bradykinesia was taken into account, the PD patients had slower motor reactions. Further, when asked to lose in response to auditory cues, they displayed a significant delay in cognitive processing as compared to the healthy controls (HC), with a greater delay in the presence of a visual distracter. The error rates in the PD group were significantly higher than those in the HC group. These results suggest that PD patients are more influenced in choice reaction than the HC and by visual rather than auditory cues, especially under conditions with stimulus-response incompatibility that requires overriding habitual behavior. These data may be helpful in designing effective rehabilitation programs for PD to avoid inhibition of overlearned and contextually compatible reactions with visual distracters.

Expression of Kruppel-like factor 5 gene in human brain and association of the gene with the susceptibility to schizophrenia.

Genome-wide gene expression analysis using DNA microarray technology is a potential tool to search for unexpected genes that have a susceptibility to schizophrenia. We carried out a microarray analysis in the postmortem prefrontal cortex and found that the expression of the KLF5 gene, whose locus is on 13q21, was down-regulated in schizophrenia patients. This result was confirmed by a Western blot analysis. In a genetic study, we found that a polymorphism of the KLF5 gene (-1593T>C) was associated with schizophrenia. We identified neurons in the prefrontal cortex of human brain as sites of KLF5 expression by in situ hybridization and immunohistochemistry. KLF5 was immunohistochemically localized in granular and pyramidal cells in the hippocampus, which are the principal source of glutamatergic neurotransmission. These findings suggest that the KLF5 gene is a novel schizophrenia-susceptibility gene, and that the expression of the gene is involved in the pathophysiology of schizophrenia via glutamatergic neurotransmission.

Phenotypic heterogeneity within a new family with the MAPT p301s mutation.

Mutations in the gene encoding the microtubule-associated protein tau (MAPT) cause frontotemporal dementia and parkinsonism linked to chromosome 17. Clinical variability is seen not only among families with different mutations, but also among family members with the same mutation. We investigated a newly identified familial frontotemporal dementia and parkinsonism family. The disease was of early onset and was inherited as an autosomal dominant trait. Clinically, parkinsonism was the prominent and often early feature, and it preceded dementia. Three autopsied cases shared involvement predominantly in the frontal and temporal lobes and also in the subcortical nuclei, including substantia nigra, globus pallidus, and subthalamic nucleus, that microscopically consisted of neuronal loss, microvacuolation, and astrocytic fibrosis. Immunohistochemistry demonstrated neuropil threads, ballooned cells, and glial fibrillary tangles. Sequencing analysis of the MAPT gene showed an alteration in one allele, resulting in a P301S substitution. These findings suggest that the MAPT P301S mutation can cause pathologically subcortical-predominant, neuropil thread-rich, tau-containing lesions, which could result in consistent parkinsonism. Our study confirms the notion that the phenotype observed in affected individuals from P301S MAPT mutation families is heterogeneous and is broader than the phenotypes seen to date in affected family members carrying other MAPT mutations.

Inflammatory glial activation in the brain of a patient with hereditary sensory neuropathy type 1 with deafness and dementia.

The brain of a patient with hereditary sensory neuropathy type 1 (HSN-1) associated with sensorineural deafness and early-onset dementia was neuropathologically investigated. Widespread neuronal degeneration in cerebral neocortex, hippocampus and basal ganglia was revealed, accounting for the clinical features. Loss of neurons with ballooning of residual neurons was remarkable in the hippocampus and frontal, parietal, and occipital lobes. Neuronal degeneration in these regions was accompanied by axonal dystrophy and glial reactions such as microgliosis and astrocytosis, however, only glial responses were prominent in the basal ganglia, brain-stem and cerebellum with mild neuronal loss. These results indicate that the widespread neuronal degeneration may be accelerated by inflammatory processes including glial activation in the brain of a patient with HSN-1 associated with deafness and dementia.

Expression of septin 3 isoforms in human brain.

Septin 3 is a novel member of the septin subfamily of GTPase domain proteins. Human septin 3 was originally cloned during a screening of genes expressed in human teratocarcinoma cells induced to differentiate with retinoic acid. Alternative splicing of the septin 3 gene transcript produces two isoforms, A and B, in the human brain, though their regional expression and physiological function remain to be determined. The purpose of the present study was to identify the expression patterns of human septin 3 isoforms in normal human brain and a human neuroblastoma cell line, SH-SY5Y, after retinoic acid-induced differentiation. The expression and distribution patterns of septin 3 isoforms A and B were similar and resembled that of another septin, CDCrel-1. Septin 3A and 3B were expressed in normal human brain in a region-specific manner, with the highest level in the temporal cortex and hippocampus and the lowest level in the brainstem regions. Prominent immunoreactivity was observed diffusely in the neocortices in association with neuropils and punctate structures suggestive of synaptic junctions. Immunoprecipitation studies revealed that septin 3A, 3B, and CDCrel-1 form a complex in the frontal cortex of human brain. These findings, taken together, suggest that septin 3A and 3B, along with CDCrel-1, play some fundamental role(s) in synaptogenesis and neuronal development.

Nanomolar amyloid beta protein activates a specific PKC isoform mediating phosphorylation of MARCKS in Neuro2A cells.

Myristoylated alanine-rich C kinase substrate (MARCKS), a protein associated with cell growth, neurosecretion and macrophage activation, is activated by protein kinase C (PKC) phosphorylation. We reported that amyloid beta protein (Abeta) activated MARCKS through a tyrosine kinase and PKC-delta in rat cultured microglia. Here we report that Abeta signaling pathway through a specific PKC isoform is involved in the phosphorylation of MARCKS in Neuro2A cells. Selective PKC inhibitors but not tyrosine kinase inhibitors significantly inhibited the phosphorylation of MARCKS induced by Abeta. Abeta selectively activated PKC-alpha among the four PKC isoforms localized in Neuro2A cells. PKC-alpha activated by Abeta directly phosphorylated a recombinant MARCKS in vitro, Translocation of PKC-alpha from the cytoplasm to the membrane and accumulation of phospho-MARCKS in the cytoplasm were induced by Abeta. These results suggest involvement of a phosphoinositide signaling system through PKC-alpha in the phosphorylation of MARCKS in neurons, an event which may be associated with mechanisms underlying neurotrophic and neurotoxic effects of Abeta.