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Abstract Aim Nicotinic acetylcholine receptors (nAChRs) expressed in midbrain dopaminergic (mDA) neurons modulate mDA neuronal activity. However, their expression patterns and functional roles during mDA neuronal development remain unknown. Here, we profiled the expression and function of nAChR subtypes during mDA neuron differentiation from human induced pluripotent stem cells (hiPSCs). Methods Midbrain dopaminergic neurons were differentiated from hiPSCs using a recently developed proprietary method that replicates midbrain development. The expression patterns of developmental marker proteins were monitored during mDA neuronal differentiation using immunohistochemical analysis. Gene expression of nAChR subtypes was analyzed by reverse transcription polymerase chain reaction. Pharmacological nAChR agonists and antagonists were used to reveal the role of the α6 nAChR subunit in the differentiation of mDA neurons from hiPSCs. Results CHRNA4 expression was detected at the mDA neural progenitor stage, whereas CHRNA6 expression began during the mDA neuronal stage. CHRNA7 was expressed throughout the differentiation process, including in the undifferentiated hiPSCs. We also found that LMO3, a gene expressed in a subset of substantia nigra pars compacta (SNC) DA neurons in the midbrain, showed increased expression following nicotine treatment in a concentration‐dependent manner. Additionally, 5‐iodo A85380, a selective α6 nAChR agonist, also increased LMO3 expression in hiPSC‐derived mDA neurons, and this increase was suppressed by simultaneous treatment with bPiDi, a selective α6 nAChR antagonist. Conclusion Our findings suggest that stimulating the α6 nAChR subunit on hiPSC‐derived mDA neurons may induce neuronal maturation that is biased toward SNC DA neurons.

Background The AT(N) classification was proposed for categorising individuals according to biomarkers. However, AT(N) profiles may vary depending on the markers chosen and the target population.Methods We stratified 177 individuals who participated in the Japanese Alzheimer’s Disease Neuroimaging Initiative by AT(N) classification according to cerebrospinal fluid (CSF) biomarkers. We compared the frequency of AT(N) profiles between the classification using total tau and neurofilament light chain (NfL) as N markers (AT(N)tau and AT(N)NfL). Baseline characteristics, and longitudinal biological and clinical changes were examined between AT(N) profiles.Results We found that 9% of cognitively unimpaired subjects, 49% of subjects with mild cognitive impairment, and 61% of patients with Alzheimer’s disease (AD) dementia had the biological AD profile (ie, A+T+) in the cohort. The frequency of AT(N) profiles substantially differed between the AT(N)tau and AT(N)NfL classifications. When we used t-tau as the N marker (AT(N)tau), those who had T− were more frequently assigned to (N)−, whereas those who had T+were more frequently assigned to (N)+ than when we used NfL as the N marker (AT(N)NfL). During a follow-up, the AD continuum group progressed clinically and biologically compared with the normal biomarker group in both the AT(N)tau and AT(N)NfL classifications. More frequent conversion to dementia was observed in the non-AD pathological change group in the AT(N)tau classification, but not in the AT(N)NfL classification.Conclusions AT(N)tau and AT(N)NfL in CSF may capture different aspects of neurodegeneration and provide a different prognostic value. The AT(N) classification aids in understanding the AD continuum biology in various populations.

Abstract HLA genotype-clinical phenotype correlations are not established for multiple sclerosis (MS) and neuromyelitis optica spectrum disorders (NMOSD). We studied HLA-DRB1/DPB1 genotype–phenotype correlations in 528 MS and 165 NMOSD cases using Japan MS/NMOSD Biobank materials. HLA-DRB1*04:05, DRB1*15:01 and DPB1*03:01 correlated with MS susceptibility and DRB1*01:01, DRB1*09:01, DRB1*13:02 and DPB1*04:01 were protective against MS. HLA-DRB1*15:01 was associated with increased optic neuritis and cerebellar involvement and worsened visual and pyramidal functional scale (FS) scores, resulting in higher progression index values. HLA-DRB1*04:05 was associated with younger onset age, high visual FS scores, and a high tendency to develop optic neuritis. HLA-DPB1*03:01 increased brainstem and cerebellar FS scores. By contrast, HLA-DRB1*01:01 decreased spinal cord involvement and sensory FS scores, HLA-DRB1*09:01 decreased annualized relapse rate, brainstem involvement and bowel and bladder FS scores, and HLA-DRB1*13:02 decreased spinal cord and brainstem involvement. In NMOSD, HLA-DRB1*08:02 and DPB1*05:01 were associated with susceptibility and DRB1*09:01 was protective. Multivariable analysis revealed old onset age, long disease duration, and many relapses as independent disability risks in both MS and NMOSD, and HLA-DRB1*15:01 as an independent risk only in MS. Therefore, both susceptibility and protective alleles can influence the clinical manifestations in MS, while such genotype–phenotype correlations are unclear in NMOSD.

Human induced pluripotent stem cells (hiPSCs) are powerful tools for modeling human brain development and treating neurodegenerative diseases. Here we established a robust protocol with high scalability for generating striatal medium spiny neurons (MSNs) from hiPSCs using small molecules under two- and three-dimensional culture conditions. Using this protocol, GSH2+ lateral ganglionic eminence (LGE) progenitors were generated in two-dimensional culture by Sonic hedgehog signaling activation using purmorphamine, WNT signaling inhibition using XAV939, and dual-SMAD inhibition using LDN193189 and A83-01. Quantitative PCR analysis revealed sequential expression of LGE and striatal genes during differentiation. These LGE progenitors subsequently gave rise to DARPP32+ MSNs exhibiting spontaneous and evoked monophasic spiking activity. Applying this protocol in three-dimensional culture, we generated striatal neurospheres with gene expression profiles and cell layer organization resembling that of the developing striatum, including distinct ventricular and subventricular zones and DARPP32+ neurons at the surface. This protocol provides a useful experimental model for studying striatal development and yields cells potentially applicable for regenerative medicine to treat striatum-related disorders such as Huntington’s disease.

Objectives Multiple system atrophy (MSA) is a refractory neurodegenerative disease, but novel treatments are anticipated. An accurate natural history of MSA is important for clinical trials, but is insufficient. This regional registry was launched to complement clinical information on MSA.Setting Patient recruitment started in November 2014 and is ongoing at the time of submission. The number of participating facilities was 66. Postal surveys were sent to medical facilities and patients with MSA in Hokkaido, Japan.Participants After obtaining written consent from 196 participants, 184 overview surveys and 115 detailed surveys were conducted.Primary and secondary outcome measures An overview survey evaluated conformity to diagnostic criteria and a detailed survey implemented an annual assessment based on the Unified Multiple System Atrophy Rating Scale (UMSARS).Results At the time of registration, 58.2% of patients were diagnosed with cerebellar symptoms predominant type MSA (MSA-C) and 29.9% were diagnosed with parkinsonism predominant type MSA (MSA-P). UMSARS Part Ⅳ score of 4 or 5 accounted for 53.8% of participants. The higher the UMSARS Part Ⅳ score, the higher the proportion of MSA-P. At baseline, levodopa was used by 69 patients (37.5%) and the average levodopa dose was 406.7 mg/day. The frequency of levodopa use increased over time. Eleven cases changed from MSA-C to MSA-P during the study, but the opposite was not observed. Information about survival and causes of death was collected on 54 cases. Half of deaths were respiratory-related. Sudden death was recorded even in the group with UMSARS Part Ⅳ score of 1.Conclusions This study is the first large-scale prospective MSA cohort study in Asia. MSA-C was dominant, but the use of antiparkinsonian drugs increased over the study period. Changes from MSA-C to MSA-P occurred, but not vice versa.

Amyloid-β (Aβ) accumulation and tauopathy are considered the pathological hallmarks of Alzheimer’s disease (AD), but attenuation in choline signaling, including decreased nicotinic acetylcholine receptors (nAChRs), is evident in the early phase of AD. Currently, there are no drugs that can suppress the progression of AD due to a limited understanding of AD pathophysiology. For this, diagnostic methods that can assess disease progression non-invasively before the onset of AD symptoms are essential, and it would be valuable to incorporate the concept of neurotheranostics, which simultaneously enables diagnosis and treatment. The neuroprotective pathways activated by nAChRs are attractive targets as these receptors may regulate microglial-mediated neuroinflammation. Microglia exhibit both pro- and anti-inflammatory functions that could be modulated to mitigate AD pathogenesis. Currently, single-cell analysis is identifying microglial subpopulations that may have specific functions in different stages of AD pathologies. Thus, the ability to image nAChRs and microglia in AD according to the stage of the disease in the living brain may lead to the development of new diagnostic and therapeutic methods. In this review, we summarize and discuss the recent findings on the nAChRs and microglia, as well as their methods for live imaging in the context of diagnosis, prophylaxis, and therapy for AD.

Activation of SIRT1, an NAD+-dependent protein deacetylase, ameliorates muscular pathophysiology of δ-sarcoglycan-deficient TO-2 hamsters and dystrophin-deficient mdx mice. We found that SIRT1 was highly expressed beneath the cellular membranes of muscle cells. To elucidate functional roles of SIRT1 on muscles, skeletal muscle-specific SIRT1 knockout mice (SIRT1-MKO) were generated. SIRT1-MKO mice showed muscular pathology similar to mild muscular dystrophies with increased numbers of centrally nucleated small myofibers and decreased numbers of middle-sized (2000-3001 μm2) myofibers compared to those of wild-type (WT) mice. Accordingly, SIRT1-MKO mice showed significantly decreased exercise capacity in treadmill and inverted hanging tests with higher levels of serum creatine kinase activities compared with those in WT mice. Evans blue dye uptake after exercise was greater in the muscles of SIRT1-MKO than those of WT mice, suggesting membrane fragility in SIRT1-MKO mice. Because SIRT1 was dominantly localized beneath the membranes of muscular cells, SIRT1 may have a new role in the membranes. We found that levels of fluorescent FM1-43 dye intake after laser-induced membrane disruption in C2C12 cells were significantly increased by SIRT1 inhibitors or Sirt1-siRNA compared with those of control cells. Inhibition of SIRT1 or SIRT1-knockdown severely disturbed the dynamic aggregation of membrane vesicles under the injured site but did not affect expression levels of membrane repair proteins. These data suggested that SIRT1 had a critical role in the resealing of membrane-ruptured muscle cells, which could affect phenotypes of SIRT1-MKO mice. To our knowledge, this report is the first to demonstrate that SIRT1 affected plasma-membrane repair mechanisms.

In an analysis of amyloid pathology in Alzheimer disease, we used an in situ approach to identify amyloid-β (Aβ) accumulation and oxidative damage to nucleic acids in postmortem brain tissue of the hippocampal formation from subjects with Alzheimer disease. When carboxyl-terminal-specific antibodies directed against Aβ40 and Aβ42 were used for immunocytochemical analyses, Aβ42 was especially apparent within the neuronal cytoplasm, at sites not detected by the antibody specific to Aβ-oligomer. In comparison to the Aβ42-positive neurons, neurons bearing oxidative damage to nucleic acids were more widely distributed in the hippocampus. Comparative density measurements of the immunoreactivity revealed that levels of intraneuronal Aβ42 were inversely correlated with levels of intraneuronal 8-hydroxyguanosine, an oxidized nucleoside (r=− 0.61, p

Obesity and type 2 diabetes are risk factors of Alzheimer's disease (AD). We reported that a high fat diet (HFD) promotes amyloid precursor protein (APP) cleavage by β-site APP cleaving enzyme 1 (BACE1) without increasing BACE1 levels in APP transgenic mice. However, the detailed mechanism had remained unclear. Here we demonstrate that HFD promotes BACE1/Adaptor protein-2 (AP-2)/clathrin complex formation by increasing AP-2 levels in APP transgenic mice. In Swedish APP overexpressing Chinese hamster ovary (CHO) cells as well as in SH-SY5Y cells, overexpression of AP-2 promoted the formation of BACE1/AP-2/clathrin complex, increasing the level of the soluble form of APP β (sAPPβ). On the other hand, mutant D495R BACE1, which inhibits formation of this trimeric complex, was shown to decrease the level of sAPPβ. Overexpression of AP-2 promoted the internalization of BACE1 from the cell surface, thus reducing the cell surface BACE1 level. As such, we concluded that HFD may induce the formation of the BACE1/AP-2/clathrin complex, which is followed by its transport of BACE1 from the cell surface to the intracellular compartments. These events might be associated with the enhancement of β-site cleavage of APP in APP transgenic mice. Here we present evidence that HFD, by regulation of subcellular trafficking of BACE1, promotes APP cleavage.

DJ-1 has recently been shown to be responsible for onset of familial Parkinson’s disease (PD), PARK7. DJ-1 has been shown to play roles in transcriptional regulation and anti-oxidative stress, and loss of its function is thought to trigger onset of PD. In this study, a recombinant DJ-1 protein was administrated into the brain of PD model rats that had been injected to 6-hydroxydopamine (6-OHDA) in the left substantia nigra. PD phenotypes, including dopaminergic neuron death in the substantia nigra, decrease in dopamine, and dopamine transporter levels in the striatum, and motor abnormality, were dramatically improved by wild-type DJ-1 but not L166P DJ-1, a mutant form of DJ-1 found in PD patients. Furthermore, production of reactive oxygen species and cell death induced by 6-OHDA in SH-SY5Y cells and mesencephalic neurons were inhibited by addition of the recombinant DJ-1. These findings suggest that DJ-1 is a therapeutic target for PD.

Presenilin 1 (PS1) is a multifunctional protein, and its mutations are highly related to familial Alzheimer’s disease (AD). In this study, we examined the effects of PS1 overexpression on neuronal morphology using SH-SY5Y cells. Overexpression of dominant-negative D385A PS1 induced morphological change and impairment of neurite formation, while those of wild-type and pathogenic P117L mutant PS1 did not change cellular morphology compared with native cells. Moreover, filopodium-formation-related proteins were decreased only in cells overexpressing D385A PS1. Therefore, PS1 may be involved in neuritogenesis and morphological change in SH-SY5Y cells, and P117L mutation may linked to AD by different mechanisms. Keywords:: presenilin 1, SH-SY5Y cell, neuritogenesis

The function of microglia in the brain parenchyma is not fully understood. Occlusion of the middle cerebral artery (MCA) and reperfusion caused behavioral dysfunction with massive neuronal loss in the rat cerebral cortex and striatum. When exogenous microglia were microinjected into the intracerebroventricle (i.c.v.) during MCA occlusion, focal ischemia-induced behavioral dysfunction was significantly inhibited. At that time, many microglia migrated into the ischemic lesion, and microglia-derived neuron-like cells were barely detectable. These results suggest that exogenous microglia protect against focal ischemia-induced neurodegeneration and improve behavioral dysfunction. Keywords:: behavioral recovery, microglia, focal brain ischemia

Parkinson’s disease is characterized by dopaminergic neuronal death and the presence of Lewy bodies in the substantia nigra pars compacta (SNpc). α-Synuclein and ubiquitin are components of Lewy bodies, but the process of Lewy body formation and the relationship between inclusion formation and dopaminergic neuronal death have not been resolved. In this study, unilateral intranigral microinjection of 6-hydroxydopamine caused a significant loss of tyrosine hydroxylase-immunopositive neurons in both the substantia nigra and striatum and apomorphine-induced contralateral rotation. The co-administration of proteasome inhibitors, such as lactacystin or carbobenzoxy-L-leucyl-L-leucyl-L-leucinal (MG-132), significantly prevented both dopaminergic neurodegeneration and apomorphine-induced rotational asymmetry. Proteasome inhibitors markedly formed intracellular protein inclusions labeled by thioflavin-S in the SNpc. Inclusion-like immunoreactivities for α-synuclein and ubiquitin were detected after 4 weeks. These results suggest that proteasome plays an important role in both the early phase of dopaminergic neuronal death and inclusion body formation. Keywords:: proteasome inhibitor, neuroprotection, dopaminergic neuron, substantia nigra, Parkinson’s disease

Embryonic stem (ES) cells have many of the characteristics of an optimal cell source for cell-replacement therapy. Although the usefulness of the in vitro generation of dopamine (DA)-neural precursors from ES cells has been widely discussed, functional recovery in animal models of Parkinson’s disease is not fully understood. In 6-hydroxydopamine-lesioned rats, apomorphine markedly induced contralateral rotation. Apomorphine-induced rotation was significantly reduced by transplantation of neuron-like cells that had differentiated from mouse ES cells using nicotinamide, but not L-lysine. In addition, methamphetamine-induced ipsilateral rotation was significantly reduced. On the other hand, picrotoxin did not inhibit apomorphine-induced rotational asymmetry. Fluoxetine alone and fenfluramine alone induced slight contralateral rotation and rotation in both directions, respectively, and these effects were similar in transplanted rats. Although immunoreactivity for tyrosine hydroxylase (TH) was almost completely lost in the ipsilateral striatum in hemiparkinsonian rats, TH immunoreactivity was detected in transplanted cells and sprouting fibers. In contrast, immunoreactivities for γ-aminobutyric acid (GABA) and serotonin (5-HT) neurons were not changed. These results suggest that improvement of rotational behavior may be induced predominantly by transplantation of nicotinamide-treated ES cell-derived DA neurons, rather than by changes in the activities of GABA or 5-HT neural systems, in hemiparkinsonian rats. Keywords:: mouse embryonic stem cell, dopaminergic differentiation, transplantation, rat striatum, Parkinson’s disease

Alzheimer’s disease (AD) is characterized by the accumulation of extracellular amyloid-β (Aβ) fibrils with microglia. Recently, there has been great interest in the microglial phagocytosis of Aβ, because the microglial pathway is considered to be one of the Aβ clearance pathways in the brain parenchyma. However, the mechanism of microglial phagocytosis of Aβ is not fully understood and, thus, was investigated in this study. At one minute after exposure to Aβ(1 – 42) (Aβ42), Aβ immunoreactivity was detected at the cell surface of microglia. After 1 h, marked immunoreactivity was observed in the cytosolic vesicles. At 12 h, delayed phagocytosis of fibrillar Aβ42 was also observed with the formation of a large phagocytic cup. The microglial cell shape rapidly changed to an ameboid form during the process of phagocytosis. Although neither neural Wiskott-Aldrich syndrome protein (N-WASP) nor WASP interacting SH3 protein (WISH) immunoreactivity was co-localized with filamentous actin (F-actin) distribution, both WASP family verprolin-homologous protein (WAVE) and Rac1 immunoreactivity was co-localized with F-actin in the lamellipodia of phogocytic microglia. These results suggest that WAVE and Rac1 participate in the phagocytosis of Aβ42 by microglia.

It has been known that rotenone and 1-methyl-4-phenylpyridinium ion (MPP+, a metabolite of MPTP), which inhibit mitochondrial complex I, are useful tools for parkinsonian models in vertebrates such as primates and rodents. Planarian, an invertebrate flatworm, has a high potential for regeneration, and dopamine plays a key role in its behavior. In the present study, we examined a cloned planarian, the GI strain from Dugesia japonica. Planarians that were treated with rotenone or MPTP underwent autolysis and individual death in a concentration- and time-dependent manner. In addition, these effects induced by rotenone or MPTP were inhibited by several antiparkinsonian drugs and caspase inhibitors. These results suggest that the degeneration of planarian dopaminergic system induced by rotenone or MPTP may be mediated through caspase-like activation.

In Alzheimer’s disease, fibrillar amyloid-β (Aβ) peptides form senile plaques associated with microglia. However, the relationship between Aβ peptides and microglia is not fully understood. In this study, the incubation of Aβ1-40 (Aβ40) produced small oligomers, while incubation with Aβ1-42 (Aβ42) caused large molecular aggregates. Microglial production of nitrite, interleukin-6 and tumor necrosis factor-a was induced by Aβ40, but not Aβ42. This production was significantly reduced by 15-deoxy-Δ12,14 prostaglandin J2, and it was completely suppressed by β-sheet breaker peptide, Leu-Pro-Phe-Phe-Asp. These results suggest that small oligomers, rather than large molecular aggregates, mediate microglial activation induced by Aβ peptides.

High fat diet (HFD) is prevalent in many modern societies and HFD-induced metabolic condition is a growing concern worldwide. It has been previously reported that HFD clearly worsens cognitive function in amyloid precursor protein (APP) transgenic mice. On the other hand, we have demonstrated that voluntary exercise in an enriched environment is an effective intervention to rescue HFD-induced β-amyloid (Aβ) deposition and memory deficit. However, it had been unclear whether consumption of HFD after exercising abolished the beneficial effect of exercise on the inhibition of Alzheimer's disease (AD) pathology. To examine this question, we exposed wild type (WT) and APP mice fed with HFD to exercise conditions at different time periods. In our previous experiment, we gave HFD to mice for 20 weeks and subjected them to exercise during weeks 10-20. In the present study, mice were subjected to exercise conditions during weeks 0-10 or weeks 5-15 while being on HFD. Interestingly, we found that the effect of exercise during weeks 0-10 or weeks 5-15 on memory function was not abolished in WT mice even if they kept having HFD after finishing exercise. However, in APP transgenic mice, HFD clearly disrupted the effect of exercise during weeks 0-10 or weeks 5-15 on memory function. Importantly, we observed that the level of Aβ oligomer was significantly elevated in the APP mice that exercised during weeks 0-10: this might have been caused by the up-regulation of Aβ production. These results provide solid evidence that continuation of exercise is necessary to rescue HFD-induced aggravation of cognitive decline in the pathological setting of AD.

In Alzheimer disease (AD) patient brains, the accumulation of amyloid-β (Aβ) peptides is associated with activated microglia. Aβ is derived from the amyloid precursor protein; two major forms of Aβ, that is, Aβ1-40 (Aβ40) and Aβ1-42 (Aβ42), exist. We previously reported that rat microglia phagocytose Aβ42, and high mobility group box protein 1 (HMGB1), a chromosomal protein, inhibits phagocytosis. In the present study, we investigated the effects of exogenous HMGB1 on rat microglial Aβ40 phagocytosis. In the presence of exogenous HMGB1, Aβ40 markedly increased in microglial cytoplasm, and the reduction of extracellular Aβ40 was inhibited. During this period, HMGB1 was colocalized with Aβ40 in the cytoplasm. Furthermore, exogenous HMGB1 inhibited the degradation of Aβ40 induced by the rat microglial cytosolic fraction. Thus, extracellular HMGB1 may internalize with Aβ40 in the microglial cytoplasm and inhibit Aβ40 degradation by microglia. This may subsequently delay Aβ40 clearance. We further confirmed that in AD brains, the parts of senile plaques surrounded by activated microglia are composed of Aβ40, and extracellular HMGB1 is deposited on these plaques. Taken together, microglial Aβ phagocytosis dysfunction may be caused by HMGB1 that accumulates extracellularly on Aβ plaques, and it may be critically involved in the pathological progression of AD.

Cu/Zn superoxide dismutase (SOD1) is a major component of Lewy body-like hyaline inclusion (LBHI) found in the postmortem tissue of SOD1-linked familial amyotrophic lateral sclerosis (FALS) patients. In our recent studies, 14-3-3 proteins have been found in the ubiquitinated inclusions inside the anterior horn cells of spinal cords with sporadic amyotrophic lateral sclerosis (ALS). To further investigate the role of 14-3-3 proteins in ALS, we performed immunohistochemical analysis of 14-3-3 proteins and compared their distributions with those of SOD1 in FALS patients and SOD1-overexpressing mice.We examined the postmortem brains and the spinal cords of three FALS cases (A4V SOD1 mutant). Transgenic mice expressing the G93A mutant human SOD1 (mutant SOD1-Tg mice), transgenic mice expressing the wild-type human SOD1 (wild-type SOD1-Tg mice), and non-Tg wild-type mice were also subjected to the immunohistochemical analysis.In all the FALS patients, LBHIs were observed in the cytoplasm of the anterior horn cells, and these inclusions were immunopositive intensely for pan 14-3-3, 14-3-3β, and 14-3-3γ. In the mutant SOD1-Tg mice, a high degree of immunoreactivity for misfolded SOD1 (C4F6) was observed in the cytoplasm, with an even greater degree of immunoreactivity present in the cytoplasmic aggregates of the anterior horn cells in the lumbar spinal cord. Furthermore, we have found increased 14-3-3β and 14-3-3γ immunoreactivities in the mutant SOD1-Tg mice. Double immunofluorescent staining showed that C4F6 and 14-3-3 proteins were partially co-localized in the spinal cord with FALS and the mutant SOD1-Tg mice. In comparison, the wild-type SOD1-Tg and non-Tg wild-type mice showed no or faint immunoreactivity for C4F6 and 14-3-3 proteins (pan 14-3-3, 14-3-3β, and 14-3-3γ) in any neuronal compartments.These results suggest that 14-3-3 proteins may be associated with the formation of SOD1-containing inclusions, in FALS patients and the mutant SOD1-Tg mice.

Parkinson's disease (PD) is a common progressive neurodegenerative disorder. The major pathological hallmarks of PD are the selective loss of nigrostriatal dopaminergic neurons and the presence of intraneuronal aggregates termed Lewy bodies (LBs), but the pathophysiological mechanisms are not fully understood. Epidemiologically, environmental neurotoxins such as pesticides are promising candidates for causative factors of PD. Oxidative stress and mitochondrial dysfunction induced by these toxins could contribute to the progression of PD. While most cases of PD are sporadic, specific mutations in genes that cause familial forms of PD have led to provide new insights into its pathogenesis. This paper focuses on animal models of both toxin-induced and genetically determined PD that have provided significant insight for understanding this disease. We also discuss the validity, benefits, and limitations of representative models.

Background: The mental rotation task is well-known for the assessment of visuospatial function; however, it has not been used for screening of dementia patients.Objective: The aim of this study was to create a simple screening test for patients with mild cognitive impairment (MCI) and Alzheimer's disease (AD) by focusing on non-amnestic symptoms.Methods: Age-matched healthy controls (age 75.3±6.8), patients with MCI (76.5±5.5), and AD (78.2±5.0) participated in this study. They carried out mental rotation tasks targeting geometric graphics or alphabetical characters with three rotating angles (0°, 90°, and 180°) and indicated the correct answer. Response accuracy and reaction time were recorded along with their eye movements using an eye tracker. To quantify their visual processing strategy, the run count ratio (RC ratio) was calculated by dividing the mean number of fixations in incorrect answers by that in correct answers.Results: AD patients showed lower accuracy and longer reaction time than controls. They also showed a significantly greater number of fixation and smaller saccade amplitude than controls, while fixation duration did not differ significantly. The RC ratio was higher for AD, followed by MCI and control groups. By setting the cut-off value to 0.47 in the 180° rotating angle task, we could differentiate MCI patients from controls with a probability of 80.0%.Conclusions: We established a new screening system for dementia patients by evaluating visuospatial function. The RC ratio during a mental rotation task is useful for discriminating MCI patients from controls. [ABSTRACT FROM AUTHOR]

In response to changes of the central nervous system environment, microglia are capable of acquiring diverse phenotypes for cytotoxic or immune regulation and resolution of injury. Alzheimer's disease (AD) pathology also induces several microglial activations, resulting in production of pro-inflammatory cytokines and reactive oxygen species or clearance of amyloid-β (Aβ) through phagocytosis. We previously demonstrated that microglial activation and increase in oxidative stress started from the middle age in APPswe/PS1dE9 mice, and hypothesized that M1 activation occurs in middle-aged AD mice by Aβ stimulation. In the present study, we analyzed in vivo expressions of pro-inflammatory cytokines (M1 microglial markers), M2 microglial markers, and suppressor of cytokine signaling (SOCS) family, and examined the microglial phenotypic profile in APPswe/PS1dE9 mice. Then we compared the in vitro gene expression patterns of Aβ- and lipopolysaccharide (LPS)-stimulated primary-cultured microglia. Microglia in APPswe/PS1dE9 mice exhibited an M1-like phenotype, expressing tumor necrosis factor α (TNFα) but not interleukin 6 (IL6). Aβ-stimulated primary-cultured microglia also expressed TNFα but not IL6, whereas LPS-stimulated primary-cultured microglia expressed both pro-inflammatory cytokines. Furthermore, both microglia in APPswe/PS1dE9 mice and Aβ-stimulated primary-cultured microglia expressed SOCS3. Reduction of SOCS3 expression in Aβ-challenged primary-cultured microglia resulted in upregulation of IL6 expression. Our findings indicate that SOCS3 suppresses complete polarization to M1 phenotype through blocking IL6 production, andAβ-challenged primary-cultured microglia replicate the in vivo gene expression pattern of microglia in APPswe/PS1dE9 mice.Aβmay induce the M1-like phenotype through blocking of IL6 by SOCS3. [ABSTRACT FROM AUTHOR]

Previously, DJ-1 modulator UCP0054278/comp-B was identified by virtual screening, where comp-B interacts with DJ-1 to produce antioxidant and neuroprotective responses in Parkinson's disease models. However, the effect of comp-B in an in vivo Alzheimer's disease (AD) model is yet undetermined. Thus, we examined the effect of comp-B on spatial learning, memory, and amyloid-’ (A’) clearance in a transgenic mouse model of AD. We found that comp-B resolved the cognitive deficits, reduced insoluble A’42 levels, and prevented the degeneration of synaptic functions, thereby suggesting that comp-B may become a major compound for AD treatment. [ABSTRACT FROM AUTHOR]

Background: Higher latitude and human leukocyte antigen (HLA)-DRB1*04:05 increase susceptibility to multiple sclerosis (MS) in the Japanese population, but their effects on disease severity are unknown. We aimed to clarify the effects of latitude and the HLA-DRB1 and HLA-DPB1 genes on disease severity in Japanese patients with MS.Methods: We enrolled 247 MS patients and 159 healthy controls (HCs) from the northernmost main island of Japan, Hokkaido Island (42-45° north), and 187 MS patients and 235 HCs from the southern half (33-35° north) of the Japanese archipelago (33-45° north). We genotyped HLA-DRB1 and HLA-DPB1 alleles, compared demographic features, and analyzed factors contributing to differences in clinical and laboratory findings between MS patients from southern and northern Japan. The Multiple Sclerosis Severity Score (MSSS), which adjusts the Kurtzke's Expanded Disability Status Scale score according to disease duration, was used to estimate disease severity.Results: The HLA-DRB1*04:05 and DRB1*15:01 alleles conferred susceptibility to MS in our Japanese population (p (corr) = 0.0004 and p (corr) = 0.0019, respectively). Southern patients had higher MSSS scores than northern patients (p = 0.003). Northern patients had higher frequencies of brain lesions meeting the Barkhof criteria (Barkhof brain lesions) and cerebrospinal fluid (CSF) IgG abnormalities than southern patients (p = 0.0012 and p < 0.0001, respectively). DRB1*04:05-positive MS patients had lower MSSS scores and lower frequencies of Barkhof brain lesions and CSF IgG abnormalities than DRB1*04:05-negative MS patients (p = 0.0415, p = 0.0026, and p < 0.0001, respectively). Multivariate analyses revealed that latitude and DRB1*04:05 were independently associated with the lowest quartile of MSSS and that latitude was positively associated with Barkhof brain lesions and CSF IgG abnormalities. DRB1*04:05 was negatively associated with these parameters. MSSS was decreased by 0.57 per DRB1*04:05 allele (p = 0.0198).Conclusions: Living at a higher latitude and carrying the DRB1*04:05 allele independently lessens MS symptom severity as defined by MSSS. However, these factors influence the frequency of Barkhof brain lesions and CSF IgG abnormalities in opposite ways; higher latitude increases the frequency of Barkhof brain lesions and CSF IgG abnormalities, whereas DRB1*04:05 decreases them. [ABSTRACT FROM AUTHOR]

Background: Alzheimer's disease (AD) is characterized by senile plaques, extracellular deposits composed primarily of amyloid-beta (Aβ), and neurofibrillary tangles, which are abnormal intracellular inclusions containing hyperphosphorylated tau. The amyloid cascade hypothesis posits that the deposition of Aβ in the brain parenchyma initiates a sequence of events that leads to dementia. However, the molecular process by which the extracellular accumulation of Aβ peptides promotes intracellular pathologic changes in tau filaments remains unclear. To elucidate this process, we presumed that astrocytes might trigger neuronal reactions, leading to tau phosphorylation. In this study, we examined AD pathology from the perspective of the astrocyte-neuron interaction. Results: A cytokine-array analysis revealed that Aβ stimulates astrocytes to release several chemical mediators that are primarily related to inflammation and cell adhesion. Among those mediators, insulin-like growth factor (IGF)-binding protein 3 (IGFBP-3) was highly upregulated. In AD brains, the expression of IGFBP-3 was found to be increased by western blot analysis, and increased expression of IGFBP-3 was observed in astrocytes via fluorescence microscopy. In addition, we reproduced the increase in IGFBP-3 after treatment with Aβ using human astrocytoma cell lines and found that IGFBP-3 was expressed via calcineurin. In AD brains, the activated forms of calcineurin were found to be increased by western blot analysis, and increased expression of calcineurin was observed in astrocytes via fluorescence microscopy. When Ser9 of glycogen synthase kinase-3β (GSK-3β) is phosphorylated, GSK-3β is controlled and tau phosphorylation is suppressed. Aβ suppresses the phosphorylation of GSK-3β, leading to tau phosphorylation. In this study, we found that IGF-? suppressed tau phosphorylation induced by Aβ, although IGFBP-3 inhibited this property of IGF-?. As a result, IGFBP-3 contributed to tau phosphorylation and cell death induced by Aβ. Conclusions: Our study suggested that calcineurin in astrocytes was activated by Aβ, leading to IGFBP-3 release. We further demonstrated that IGFBP-3 produced by astrocytes induced tau phosphorylation in neurons. Our study provides novel insights into the role of astrocytes in the induction of tau phosphorylation and suggests that IGFBP-3 could be an important link between Aβ and tau pathology and an important therapeutic target. [ABSTRACT FROM AUTHOR]

Very long-chain acyl-CoA dehydrogenase (VLCAD) deficiency is characterized by impaired mitochondrial β-oxidation of fatty acids. The fatty acid oxidation plays a significant role in energy production especially in skeletal muscle. VLCAD is one of four acyl-CoA dehydrogenases with different-chain length specificity and catalyzes the initial step in mitochondrial β-oxidation of fatty acids. While the clinical phenotypes in neonates and infants are described as severe, adolescent-onset or adult-onset VLCAD deficiency has a more benign course with only skeletal muscle involvement. These myopathic phenotypes are characterized by episodic muscle weakness and rhabdomyolysis triggered by fasting and strenuous exercise. We report a male teenager who manifested repeated episodes of rhabdomyolysis immediately after exertional exercise. Rhabdomyolysis was diagnosed based on the marked elevation of serum creatine kinase and myoglobinuria. Acylcarnitine analysis by tandem mass spectrometry (MS/MS) revealed elevation of serum tetradecenoylcarnitine (C14:1-AC), which represents an abnormal acylcarnitine profile associated with the mitochondrial β-oxidation defect. High performance liquid chromatographic analysis showed decreased production of 2-hexadecenoyl-CoA (C16:1) from palmitoyl-CoA (C16:0), indicating the defect of VLCAD activity. Direct sequencing of the acyl-CoA dehydrogenase, very long-chain gene (ACADVL) that codes VLCAD revealed a heterozygous mutation (c.1242G>C) in exon 12 (E414D), which is a novel mutation in myopathic-type VLCAD deficiency. Because VLCAD functions as a homodimer, we assume that this heterozygous mutation may exhibit dominant-negative effect. This patient remains asymptomatic thereafter by avoiding exertional exercise. The findings of reduction of enzyme activity and clinical features associated with this novel missense mutation of VLCAD are discussed. [ABSTRACT FROM AUTHOR]

Background: Mutations of the lamin A/C gene have been associated with several diseases such as Emery-Dreifuss muscular dystrophy, dilated cardiomyopathy and Charcot-Marie-Tooth disease, referred to as laminopathies. Only one report of spinal muscular atrophy and cardiomyopathy phenotype with lamin A/C gene mutations has been published. The concept that lamin A/C gene mutations cause spinal muscular atrophy has not been established. Case presentation: We report a man aged 65 years who presented with amyotrophy of lower limbs, arrhythmia and cardiac hypofunction. He showed gait disturbance since childhood, and his family showed similar symptoms. Neurological and electrophysiological findings suggested spinal muscular atrophy type 3. Gene analysis of lamin A/C gene showed a novel nonsense mutation p.Q353X (c.1057C > T). Further investigations revealed that he and his family members had cardiac diseases including atrioventricular block. Conclusions: We report the first Japanese case of spinal muscular atrophy phenotype associated with lamin A/C mutation. When a patient presents a spinal muscular atrophy phenotype and unexplained cardiac disease, especially when the family history is positive, gene analysis of lamin A/C gene should be considered. [ABSTRACT FROM AUTHOR]

The mechanisms underlying the selective neuronal death in Alzheimer's disease are largely unresolved. Nonetheless, it is apparent that the environment of the diseased brain is extremely rich in proapoptotic stimuli and that these lead to an activation of the apoptotic death cascade. However, there is surprisingly little evidence for the completion of the death pathway indicating that the apoptotic death program is terminated by a mechanism termed abortosis. This review discusses the concept of abortosis in relation to Alzheimer's disease. [ABSTRACT FROM AUTHOR]

Epidemiologic studies revealed that the prevalence of Parkinson disease is higher in males than in females and that the progression of the disease might be rapid in males compared with females. The reason for the gender difference is unknown; however, estrogens may be involved. Many studies have revealed that estrogens provide neuroprotective effects and that the protective mechanisms include antioxidant property and upregulation of Bcl-2, brain-derived neurotrophic factor, and glial cell-derived neurotrophic factor (GDNF). Upregulation of Bcl-2 or GDNF is mediated by nonnuclear estrogen receptor (ER) in addition to transcription regulation by ER. To avoid undesirable effect of estrogens, several selective ER modulators, raloxifene and genistein are considered. [ABSTRACT FROM AUTHOR]