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Abstract Since the identification of vacuolar protein sorting (VPS) 35, as a causative molecule for familial Parkinson’s disease (PD), retromer-mediated endosomal machinery has been a rising factor in the pathogenesis of the disease. The retromer complex cooperates with sorting nexin (SNX) dimer and DNAJC13, another causal molecule in PD, to transport cargoes from endosomes to the trans-Golgi network, and is also involved in mitochondrial dynamics and autophagy. Retromer dysfunction may induce neuronal death leading to PD via several biological cascades, including misfolded, insoluble α-synuclein (aS) accumulation and mitochondrial dysfunction; however, the detailed mechanisms remain poorly understood. In this study, we showed that the stagnation of retromer-mediated retrograde transport consistently occurs in different PD-mimetic conditions, i.e., overexpression of PD-linked mutant DNAJC13, excess aS induction, or toxin-induced mitochondrial dysfunction. Mechanistically, DNAJC13 was found to be involved in clathrin-dependent retromer transport as a functional modulator of SNX1 together with heat shock cognate 70 kDa protein (Hsc70), which was controlled by the binding and dissociation of DNAJC13 and SNX1 in an Hsc70 activity-dependent manner. In addition, excess amount of aS decreased the interaction between SNX1 and VPS35, the core component of retromer. Furthermore, R33, a pharmacological retromer chaperone, reduced insoluble aS and mitigated rotenone-induced neuronal apoptosis. These findings suggest that retrograde transport regulated by SNX1-retromer may be profoundly involved in the pathogenesis of PD and is a potential target for disease-modifying therapy for the disease.

Background: Recently, the hypothesis that pathological α-Synuclein propagates from the gut to the brain has gained attention. Although results from animal studies support this hypothesis, the specific mechanism remains unclear. This study focused on the intestinal fatty acid-binding protein (FABP2), which is one of the subtypes of fatty acid binding proteins localizing in the gut, with the hypothesis that FABP2 is involved in the gut-to-brain propagation of α-synuclein. The aim of this study was to clarify the pathological significance of FABP2 in the pathogenesis and progression of synucleinopathy. Methods: We examined the relationship between FABP2 and α-Synuclein in the uptake of α-Synuclein into enteric neurons using primary cultured neurons derived from mouse small intestinal myenteric plexus. We also quantified disease-related protein concentrations in the plasma of patients with synucleinopathy and related diseases, and analyzed the relationship between plasma FABP2 level and progression of the disease. Results: Experiments on α-Synuclein uptake in primary cultured enteric neurons showed that following uptake, α-Synuclein was concentrated in areas where FABP2 was localized. Moreover, analysis of the plasma protein levels of patients with Parkinson’s disease revealed that the plasma FABP2 and α-Synuclein levels fluctuate with disease duration. The FABP2/α-Synuclein ratio fluctuated more markedly than either FABP2 or α-Synuclein alone, depending on the duration of disease, indicating a higher discriminant ability of early Parkinson’s disease patients from healthy patients. Conclusions: These results suggest that FABP2 potentially contributes to the pathogenesis and progression of α-synucleinopathies. Thus, FABP2 is an important molecule that has the potential to elucidate the consistent mechanisms that lead from the prodromal phase to the onset and subsequent progression of synucleinopathies.

Abstract Background It is possible that increased synthesis of metallothioneins (MTs), Zn2+-binding proteins is linked with the protective effect of Ninjin-yoei-to (NYT) on Zn2+ toxicity ferried by amyloid β1-42 (Aβ1-42). Methods Judging from the biological half-life (18-20 h) of MTs, the effective period of newly synthesized MT on capturing Zn2+ is estimated to be approximately 2 days. In the present paper, a diet containing 3% NYT was administered to mice for 2 days and then Aβ1-42 was injected into the lateral ventricle of mice. Results MT level in the dentate granule cell layer was elevated 2 days after administration of NYT diet, while the administration reduced intracellular Zn2+ level increased 1 h after Aβ1-42 injection, resulting in rescuing neuronal death in the dentate granule cell layer, which was observed 14 days after Aβ1-42 injection. Furthermore, Pre-administration of NYT diet rescued object recognition memory loss via affected perforant pathway long-term potentiation after local injection of Aβ1-42 into the dentate granule cell layer of rats. Conclusion The present study indicates that pre-administration of NYT diet for 2 days increases synthesis of MTs, which reduces intracellular Zn2+ toxicity ferried by extracellular Aβ1-42, resulting in protecting neuronal death in the dentate gyrus and memory loss after exposure to Aβ1-42.

Abstract Background Increasing evidence suggests that alpha‐synuclein (αSyn) accumulation in cholinergic and adrenergic fibers in the skin is a useful biomarker to diagnose idiopathic Parkinson's disease (IPD). It has been widely reported that phosphorylated αSyn (p‐αSyn) deposits in autonomic fibers in IPD are a biomarker in the skin, but other tissue localizations have not been fully investigated. Objective It has been previously suggested that αSyn aggregates activate peripheral macrophages and that peripheral macrophages ingest pathological αsyn aggregates in aged rats or IPD patients. However, it remains to be elucidated whether peripheral macrophages in the skin of IPD patients accumulate αSyn. We evaluated whether (1) p‐αSyn deposits in dermal macrophages might represent a useful biomarker for IPD and (2) dermal macrophages play a role in the underlying pathogenesis of IPD. Methods We performed an immunohistological analysis of skin biopsy specimens from IPD patients and controls. Results We found that (1) p‐αSyn accumulation is present in dermal macrophages in skin biopsy specimens from patients with IPD, (2) not only dermal adrenergic fibers with p‐αSyn deposits but also dermal macrophages with p‐αSyn deposits are useful biomarkers for IPD patients and (3) the number of macrophages was significantly positively correlated with the number of macrophages with p‐αSyn deposits in the dermis of IPD patients. Interpretation Our results suggest that dermal macrophages, which are innate immune cells, play an important role in IPD patients and are a novel biomarker for IPD.

Prescription doses of levodopa in patients with advanced Parkinson’s disease (PD) are generally lower in Japan than in the United States or Europe, although Japanese guidelines for the management of PD recommend increasing the dosage as the disease progresses. However, data regarding levodopa prescription practices in patients with advanced PD in the clinical setting are limited. This retrospective observational study analyzed patterns of drug use for patients with advanced PD in Japan using claims data from hospitalized patients in the Medical Data Vision Co. database. Eligible patients had at least two PD-associated claims in two different quarters between April 1, 2008, and November 30, 2018, and a 10-item activities of daily living score

An increase in the global aging population is leading to an increase in age-related conditions such as dementia and movement disorders, including Alzheimer’s disease (AD), Parkinson’s disease (PD), and dementia with Lewy bodies (DLB). The accurate prediction of risk factors associated with these disorders is crucial for early diagnosis and prevention. Biomarkers play a significant role in diagnosing and monitoring diseases. In neurodegenerative disorders like α-synucleinopathies, specific biomarkers can indicate the presence and progression of disease. We previously demonstrated the pathogenic impact of fatty acid-binding proteins (FABPs) in α-synucleinopathies. Therefore, this study investigated FABPs as potential biomarkers for Lewy body diseases. Plasma FABP levels were measured in patients with AD, PD, DLB, and mild cognitive impairment (MCI) and healthy controls. Plasma FABP3 was increased in all groups, while the levels of FABP5 and FABP7 tended to decrease in the AD group. Additionally, FABP2 levels were elevated in PD. A correlation analysis showed that higher FABP3 levels were associated with decreased cognitive function. The plasma concentrations of Tau, GFAP, NF-L, and UCHL1 correlated with cognitive decline. A scoring method was applied to discriminate between diseases, demonstrating high accuracy in distinguishing MCI vs. CN, AD vs. DLB, PD vs. DLB, and AD vs. PD. The study suggests that FABPs could serve as potential biomarkers for Lewy body diseases and aid in early disease detection and differentiation.

The vegetative cell nucleus proceeds ahead of a pair of sperm cells located beneath the pollen tube tip during germination. The tip-localized vegetative nucleus had been considered to play a pivotal role in the control of directional pollen tube growth and double fertilization. However, we recently reported the female-targeting behavior of pollen tubes from mutant plants, of which the vegetative nucleus and sperm nuclei were artificially immotile. We showed that the apical region of the mutant pollen tubes became physiologically enucleated after the first callose plug formation, indicating the autonomously growing nature of pollen tubes without the vegetative nucleus and sperm cells. Thus, in this study, we further analyzed another Arabidopsis thaliana mutant producing physiologically enucleated pollen tubes and discussed the mechanism by which a pollen tube can grow without de novo transcription from the vegetative nucleus. We propose several possible molecular mechanisms for persistent pollen tube growth, such as the contribution of transcripts before and immediately after germination and the use of persistent transcripts, which may be important for a competitive race among pollen tubes.

Summary: Background: Dementia greatly contributes to poor prognosis in patients with Parkinson's disease (PD). We previously reported that severe olfactory dysfunction may be a good predictor of Parkinson's disease dementia (PDD). In this trial, we investigated whether early administration of donepezil to patients with severe hyposmia can reduce the development of PDD. Methods: This was a multi-centre, randomized, double-blind, parallel group, placebo-controlled trial in patients with non-demented PD with severe hyposmia (The Donepezil Application for Severe Hyposmic Parkinson's Disease [DASH-PD] study). A total of 201 patients were randomly allocated to receive donepezil or placebo in addition to standard therapy for PD. Patients were followed up every 6 months until the onset of PDD or for a maximum of 4 years. The primary endpoint was the onset of dementia. The secondary endpoint was cognitive impairment measured by Addenbrooke's Cognitive Examination-Revised (ACE-R) and the Clinical Dementia Rating (CDR).(UMIN000009958: February 2013 to May 2019). Findings: A total of 201 hyposmic patients with PD were randomly assigned to a treatment: 103 to donepezil and 98 to placebo. Overall, 141 (70%) patients completed the 4-year intervention. During follow-up, 7 of 103 (6.8%) patients in the donepezil group and 12 of 98 (12.2%) patients in the placebo group developed PDD; however, the hazard ratio of PDD incidence was not statistically significant (hazard ratio (HR), 0.609; 95% confidence interval, 0.240 to 1.547; p = 0.2969). At week 208, the patients in the donepezil group had better scores on the ACE-R (p

Arabidopsis pollen contains a vegetative nucleus and two sperm cells that move to the apical region during pollen tube growth. Here, Motomura et al. make use of transgenic pollen with immobilized nuclei and show that, contrary to previous assumptions, movement of the vegetative nucleus is not needed for pollen tube guidance.

BackgroundIn recent years, there has been increasing evidence that several lipid metabolism abnormalities play an important role in the pathogenesis of neurodegenerative diseases. However, it is still unclear which lipid metabolism abnormalities play the most important role in neurodegenerative diseases. Plasma lipid metabolomics (lipidomics) has been shown to be an unbiased method that can be used to explore lipid metabolism abnormalities in neurodegenerative diseases. Plasma lipidomics in neurodegenerative diseases has been performed only in idiopathic Parkinson's disease (IPD) and Alzheimer's disease (AD), and comprehensive studies are needed to clarify the pathogenesis.MethodsIn this study, we investigated plasma lipids using lipidomics in individuals with neurodegenerative diseases and healthy controls (CNs). Plasma lipidomics was evaluated by liquid chromatography-tandem mass spectrometry (LC-MS/MS) in those with IPD, dementia with Lewy bodies (DLB), multiple system atrophy (MSA), AD, and progressive supranuclear palsy (PSP) and CNs.ResultsThe results showed that (1) plasma sphingosine-1-phosphate (S1P) was significantly lower in all neurodegenerative disease groups (IPD, DLB, MSA, AD, and PSP) than in the CN group. (2) Plasma monohexylceramide (MonCer) and lactosylceramide (LacCer) were significantly higher in all neurodegenerative disease groups (IPD, DLB, MSA, AD, and PSP) than in the CN group. (3) Plasma MonCer levels were significantly positively correlated with plasma LacCer levels in all enrolled groups.ConclusionS1P, Glucosylceramide (GlcCer), the main component of MonCer, and LacCer are sphingolipids that are biosynthesized from ceramide. Recent studies have suggested that elevated GlcCer and decreased S1P levels in neurons are related to neuronal cell death and that elevated LacCer levels induce neurodegeneration by neuroinflammation. In the present study, we found decreased plasma S1P levels and elevated plasma MonCer and LacCer levels in those with neurodegenerative diseases, which is a new finding indicating the importance of abnormal sphingolipid metabolism in neurodegeneration.

Mirror writing (MW) is the production of individual letters, words, or word strings in the reverse direction. Parkinson's disease (PD) is a progressive neurodegenerative disorder, and high MW rates have been reported in patients with PD. Thus, the present study sought to identify the factors that cause MW in patients with PD. We examined the frequency of MW in patients with PD and investigated the area of the brain where such frequency inversely correlates with reduced regional cerebral metabolic rates of glucose (rCMRglc). We also examined whether this area satisfied the motor and visual monitoring hypotheses of MW that have been presented in previous studies. Thirty-six subjects with idiopathic PD and 23 healthy controls were included in the study. We asked the participants to write down words, numerals, and sentences from left to right using their dominant and non-dominant hands. Patients with PD underwent an 18F-fluorodeoxyglucose positron emission tomography scan to measure the rCMRglc. Neither the patients with PD nor the healthy subjects exhibited MW in the use of the right hand. In the use of the left hand, MW occurred in 15 of the 36 patients with PD, but in none of the healthy controls. The right intraparietal sulcus was identified as the area where rCMRglc was inversely correlated with the number of left-right reversed characters. Previous functional imaging studies have suggested that the right superior parietal cortex and intraparietal sulcus play an important role in recognizing left-right reversed letters. Therefore, dysfunction in the intraparietal sulcus may hinder the recognition of left-right reversed characters, resulting in MW. Consequently, our findings in patients with PD are consistent with the visual-monitoring hypothesis of MW.

Background. Safinamide is a selective, reversible monoamine oxidase-B inhibitor with a sodium channel inhibitory effect. Published clinical evidence supports safinamide as an effective therapy for Parkinson’s disease (PD) with wearing-off. However, to date, no consensus recommendations have been available to guide physicians in Asia on the optimal use of safinamide in clinical practice. To summarize opinions on the optimal patient profile and methods of using safinamide in common clinical scenarios, Japanese movement disorder specialists with expertise in PD investigated the perspectives of neurologists and neurosurgeons. Methods. The Delphi panel approach was used to summarize the opinions of panelists. The panel comprised doctors from Japan with extensive clinical practice experience in the use of safinamide (n = 46 at the final round). The consensus was defined as 80% or more agreement between panelists for each scenario at the final round. Results. There was a high level of agreement that patients with the following symptoms are suitable for safinamide treatment such as bradykinesia (100%), rigidity (95.7%), and/or gait disorder (89.1%) based on motor symptoms and PD-related pain (97.8%) and/or depression or apathy (93.5%) based on non-motor symptoms. Morning-off (95.7%), but not dyskinesia (71.7%), also reached consensus. The use of high-dose safinamide (100 mg/day) was recommended when the improvement in PD symptoms is insufficient and increasing the doses of other anti-PD medications is difficult (97.8%) or when the abovementioned non-motor symptoms adversely affect daily life (93.5%). Conclusions. This report provides expert perspectives on the use of safinamide for a wide range of clinical scenarios in Japan.

Background Identifying the factors that influence health-related quality of life (HRQoL) is of great scientific interest, but a potential causal relationship between treatment and HRQoL has yet to be fully elucidated. Japanese patients reported better HRQoL outcomes on the Parkinson’s Disease Questionnaire (PDQ-39) emotional well-being domain, a 6-question subset of the PDQ-39 which is considered to reflect the emotional aspects of the disease-specific HRQoL, when treated with rasagiline, than placebo, in both a monotherapy clinical trial (NCT02337725) and an adjunctive therapy clinical trial in patients with wearing-off phenomena (NCT02337738). Objective To investigate how rasagiline exerts its effect on the PDQ-39 emotional well-being domain in Japanese patients with Parkinson’s disease. Methods A path analysis was performed to assess the direct treatment effects of rasagiline on the PDQ-39 emotional well-being domain and the effects mediated indirectly through the influence on items related to motor symptoms by a post-hoc analysis of two clinical trials in Japan. Results In the monotherapy trial, the PDQ-39 emotional well-being domain was mainly affected indirectly through items related to motor symptoms (80.7%) composed of the Movement Disorder Society-Unified Parkinson’s Disease Rating Scale (MDS-UPDRS) Part II (67.2%) and Part III (13.5%). In the adjunctive therapy trial, the PDQ-39 emotional well-being domain was also mainly influenced indirectly through effects on items related to motor symptoms (1 mg/day: 54.7%, 0.5 mg/day: 57.6%) composed of MDS-UPDRS Part II (1 mg/day: 35.6%, 0.5 mg/day: 40.9%), Part III (1 mg/day: 8.0%, 0.5 mg/day: 8.3%) and mean daily OFF-time (1 mg/day: 11.1%, 0.5 mg/day: 8.4%). Conclusions The effects of rasagiline on the PDQ-39 emotional well-being domain were mediated primarily by influence on the subjective aspects of motor experiences of daily living.

Introduction: We aimed to determine whether in vivo tau deposits and monoamine oxidase B (MAO-B) detection using 18F-THK5351 positron emission tomography (PET) can assist in the differential distribution in patients with corticobasal syndrome (CBS), progressive supranuclear palsy (PSP), and Alzheimer’s disease (AD) and whether 18F-THK5351 retention of lesion sites in CBS and PSP can correlate with clinical parameters.Methods:18F-THK5351 PET was performed in 35 participants, including 7, 9, and 10 patients with CBS, PSP, and AD, respectively, and 9 age-matched normal controls. In CBS and PSP, cognitive and motor functions were assessed using the Montreal Cognitive Assessment, Addenbrooke’s Cognitive Examination–Revised, and Frontal Assessment Battery, Unified Parkinson’s Disease Rating Scale Motor Score, and PSP Rating Scale.Results:18F-THK5351 retention was observed in sites susceptible to disease-related pathologies in CBS, PSP, and AD. 18F-THK5351 uptake in the precentral gyrus clearly differentiated patients with CBS from those with PSP and AD. Furthermore, 18F-THK5351 uptake in the inferior temporal gyrus clearly differentiated patients with AD from those with CBS and PSP. Regional 18F-THK5351 retention was associated with the cognitive function in CBS and PSP.Conclusion: Measurement of the tau deposits and MAO-B density in the brain using 18F-THK5351 may be helpful for the differential diagnosis of tauopathies and for understanding disease stages.

Summary: The path of ribosomes on mRNAs can be impeded by various obstacles. One such example is halting of ribosome movement by microRNAs, but the exact mechanism and physiological role remain unclear. Here, we find that ribosome stalling caused by the Argonaute-microRNA-SGS3 complex regulates production of secondary small interfering RNAs (siRNAs) in plants. We show that the double-stranded RNA-binding protein SGS3 interacts directly with the 3′ end of the microRNA in an Argonaute protein, resulting in ribosome stalling. Importantly, microRNA-mediated ribosome stalling correlates positively with efficient production of secondary siRNAs from target mRNAs. Our results illustrate a role of paused ribosomes in regulation of small RNA function that may have broad biological implications across the plant kingdom.

We conducted a phase I study investigating the efficacy, safety, and tolerability of ONO-2160, a newly developed levodopa pro-drug, and carbidopa compared with levodopa and carbidopa to stabilize levodopa plasma concentration fluctuations in Japanese patients with Parkinson's disease. In an open-label two-period design, patients (n = 12) with Parkinson's disease received levodopa and carbidopa for 3 days before 7 days of treatment with ONO-2160 and carbidopa. Patients were primarily evaluated using the Unified Parkinson's Disease Rating Scale Part III, a Parkinson's disease symptom diary, and analysis of adverse events. Pharmacokinetic analysis of plasma levodopa concentration was also performed.ONO-2160 and carbidopa therapy stabilized effective plasma levodopa concentration. No adverse events with safety concerns were observed. The combination of ONO-2160 and carbidopa produced a prolonged and stable plasma levodopa concentration with a reduction in Unified Parkinson's Disease Rating Scale Part III total scores. The combination was well tolerated, with no safety concerns, when administered to Japanese patients with Parkinson's disease. Keywords: ONO-2160, Levodopa, Parkinson's disease, Motor fluctuations

Parkinson’s disease (PD) and multiple system atrophy are types of adult-onset neurodegenerative disorders named synucleinopathies, which are characterized by prominent intracellular α-synuclein (αSyn) aggregates. We have previously found that αSyn aggregates and the vulnerability of dopaminergic neurons in the mouse brain are partly associated with the expression of fatty acid-binding protein 3 (FABP3, heart FABP). However, it remains to be elucidated whether FABP3 accumulation is associated with αSyn aggregates in human tissues. Here, we histologically studied FABP3 expression in human tissues obtained from patients with synucleinopathies, patients with Alzheimer disease (AD) and controls. We found that (1) a variety of neurons expressed the FABP3 protein in human brain tissues, (2) FABP3 was colocalized with αSyn aggregates in the brains of individuals with synucleinopathies but not with amyloid β or p-tau aggregates in the brains of individuals with AD, and (3) FABP3 was not present in p-αSyn deposits in biopsied skin tissues from individuals with PD. These findings suggest that FABP3 expression is associated with αSyn aggregation in synucleinopathies and provide new insights into the involvement of FABP3 in synucleinopathies.

Neuroimaging evidence suggests that areas of the higher-order visual cortex, including the lateral occipital complex (LOC), are engaged in the perception of illusory contours; however, these findings remain unsubstantiated by human lesion data. Therefore, we assessed the presentation time necessary to perceive two types of illusory contours formed by Kanizsa figures or aligned line ends in patients with Parkinson's disease (PD). Additionally, we used 18F-fluorodeoxyglucose positron emission tomography (FDG-PET) to measure regional cerebral glucose metabolism in PD patients. Although there were no significant differences in the stimulus durations required for perception of illusory contours formed by aligned line ends between PD patients and controls, PD patients required significantly longer stimulus durations for the perception of Kanizsa illusory figures. Difficulty in perceiving Kanizsa illusory figures was correlated with hypometabolism in the higher-order visual cortical areas, including the posterior inferior temporal gyrus. These findings indicate an association between dysfunction in the posterior inferior temporal gyrus, a region corresponding to a portion of the LOC, and impaired perception of Kanizsa illusory figures in PD patients.

Abstract Introduction The neural substrates associated with the development of micrographia remain unknown. We aimed to elucidate the neural substrates underlying micrographia in Parkinson's disease (PD) patients. Methods Forty PD patients and 20 healthy controls underwent handwriting tests that involved free writing and copying. We measured the size of each letter and the resting cerebral glucose metabolic rate of the PD patients and another group of age‐ and sex‐matched 14 healthy controls (HCs), who had not participated in the writing tests, using resting‐state 18F‐fluorodeoxyglucose positron emission tomography. Results In the PD patients, the prevalence of consistent micrographia (CM) associated with free writing was 2.5% for both tasks. Alternatively, the prevalence of progressive micrographia (PM) was 15% for free writing and 17.5% for copying. In the PD patients, there was no significant difference in the letter sizes between these tasks, whereas the variability of the letter sizes for copying was significantly different from that for free writing. The means and decrements in letter sizes in either task were not significantly correlated with the severity of brady/hypokinesia in the PD patients. For free writing, the PD patients with PM showed glucose hypometabolism in the anterior part of the right middle cingulate cortex, including the rostral cingulate motor area, compared with those without PM. For copying, the PD patients with PM showed glucose hypometabolism in the right superior occipital gyrus, including V3A, compared with those without PM. Conclusions These findings suggest that PM in free writing in PD patients is caused by the difficulty of monitoring whether the actual handwriting movements are desirable for maintaining letter size during self‐paced handwriting. By contrast, PM in copying in PD patients is evoked by a lack of visual information about the personal handwriting and hand motions that are used as cues for maintaining letter sizes.

Parkinson’s disease (PD) is a common neurodegenerative disorder characterized by loss of dopamine neurons. Since a seminal report was published in the early twentieth century, a growing body of literature has suggested that patients with PD display characteristic personality traits, such as cautiousness and inflexibility. Notably, PD patients have also been described as “honest,” indicating that they have a remarkable tendency to avoid behaving dishonestly. In this study, we predicted that PD patients show reduced cheating behavior in opportunities for dishonest gain due to dysfunction of the dopaminergic reward system. Thirty-two PD patients without dementia and 20 healthy controls (HC) completed an incentivized prediction task where participants were rewarded based on their self-reported accuracy, affording them the opportunity to behave dishonestly. Compared with HC, PD patients showed significantly lower accuracy in the prediction task. Furthermore, the mean accuracy of PD patients was virtually equivalent to the chance level. These results indicate that PD patients exhibit reduced cheating behavior when confronted with opportunities for dishonest gain.

BACKGROUND:There is increasing evidence for predictive coding theories of psychosis, which state that hallucinations arise from abnormal perceptual priors or biases. However, psychological processes that foster abnormal priors/biases in patients suffering hallucinations have been largely unexplored. The widely recognized relationship between affective disorders and psychosis suggests a role for mood and emotion. METHODS:Thirty-six patients with dementia with Lewy bodies (DLB), a representative condition associated with psychosis of neurological origin, and 12 patients with Alzheimer's disease (AD) were enrolled. After an experimental mood induction, the participants underwent the pareidolia test, in which visual hallucination-like illusions were evoked and measured. RESULTS:In DLB patients, the number of pareidolic illusions was doubled under negative mood compared to that under neutral mood. In AD patients, there was no significant difference in the number of pareidolic responses between negative and neutral mood conditions. A signal detection theory analysis demonstrated that the observed affective modulation of pareidolic illusions was mediated through heightened perceptual bias, not sensory deterioration. CONCLUSIONS:The current findings demonstrated that abnormal perceptual priors in psychotic false perception have an affective nature, which we suggest are a type of cognitive feeling that arises in association with perception and cognition.

Mutations in vacuolar protein sorting 35 (VPS35) have been linked to familial Parkinson's disease (PD). VPS35, a component of the retromer, mediates the retrograde transport of cargo from the endosome to the trans-Golgi network. Here we showed that retromer depletion increases the lysosomal turnover of the mannose 6-phosphate receptor, thereby affecting the trafficking of cathepsin D (CTSD), a lysosome protease involved in α-synuclein (αSYN) degradation. VPS35 knockdown perturbed the maturation step of CTSD in parallel with the accumulation of αSYN in the lysosomes. Furthermore, we found that the knockdown of Drosophila VPS35 not only induced the accumulation of the detergent-insoluble αSYN species in the brain but also exacerbated both locomotor impairments and mild compound eye disorganization and interommatidial bristle loss in flies expressing human αSYN. These findings indicate that the retromer may play a crucial role in αSYN degradation by modulating the maturation of CTSD and might thereby contribute to the pathogenesis of the disease.

Freezing of gait (FOG) is one of the factors that reduce the quality of life in patients with Parkinson's disease (PD). Imagining bicycling before gait start provided improvement in FOG in 2 PD patients. Imagining and mimicking bicycling after the initiation of gait allowed the rhythmic gait to continue without interruption. We suggest that imagining and mimicking bicycling, which are nonexternal cues, could serve as a helpful therapeutic approach for the intractable freezing and interruption of gait of PD patients.

Abnormal cardiac uptake of 123I-metaiodobenzylguanidine (123I-MIBG) is a diagnostic marker of Lewy body diseases (LBDs), e.g., Parkinson's disease (PD) and dementia with Lewy bodies (DLB). Planar imaging is generally used to assess cardiac sympathetic dysfunction in 123I-MIBG scintigraphy; however, its clinical utility requires further improvement. We hypothesized that the co-registration of single-photon emission tomography (SPECT) and computed tomography (CT) images would improve the diagnostic accuracy of 123I-MIBG cardiac scintigraphy for LBDs. This study sought to evaluate the effects of SPECT/CT imaging on 123I-MIBG cardiac scintigraphy for diagnosing LBDs.We retrospectively investigated data of 54 patients (consecutive 18 patients in each PD, DLB, and idiopathic normal pressure hydrocephalus [iNPH] groups) who underwent 123I-MIBG cardiac scintigraphy (planar and SPECT/CT) because of suspected LBDs at the Tohoku University hospital from June 2012 to June 2015. We compared the diagnostic accuracies of the conventional planar 123I-MIBG method and SPECT/CT methods (manual and semi-automatic).In the conventional planar analysis, 123I-MIBG uptake decreased only in the DLB group compared with the iNPH group. In contrast, the SPECT/CT analysis revealed significantly lower 123I-MIBG uptake in both the PD and DLB groups compared with the iNPH group. Furthermore, a receiver operating characteristic analysis revealed that both the manual and semi-automatic SPECT/CT methods were superior to the conventional planar method in differentiating the 3 disorders.SPECT/CT 123I-MIBG cardiac scintigraphy can detect mild cardiac sympathetic dysfunction in LDBs. Our results suggest that the SPECT/CT technique improves diagnostic accuracy for LBDs.

The basal levels of extracellular Zn2+ are in the range of low nanomolar concentrations and less attention has been paid to Zn2+, compared to Ca2+, for synaptic activity. However, extracellular Zn2+ is necessary for synaptic activity. The basal levels of extracellular zinc are age-dependently increased in the rat hippocampus, implying that the basal levels of extracellular Zn2+ are also increased age-dependently and that extracellular Zn2+ dynamics are linked with age-related cognitive function and dysfunction. In the hippocampus, the influx of extracellular Zn2+ into postsynaptic neurons, which is often linked with Zn2+ release from neuron terminals, is critical for cognitive activity via long-term potentiation (LTP). In contrast, the excess influx of extracellular Zn2+ into postsynaptic neurons induces cognitive decline. Interestingly, the excess influx of extracellular Zn2+ more readily occurs in aged dentate granule cells and intracellular Zn2+-buffering, which is assessed with ZnAF-2DA, is weakened in the aged dentate granule cells. Characteristics (easiness) of extracellular Zn2+ influx seem to be linked with the weakened intracellular Zn2+-buffering in the aged dentate gyrus. This paper deals with the impact of synaptic Zn2+ signaling on cognition and its decline in comparison with synaptic Ca2+ signaling.

We investigated the effects of Evodiae Fructus and synephrine, one of the components of Evodiae Fructus, on blood vessels. We found that Evodiae Fructus (1 × 10−4 g/mL) had constrictive effects on rat aorta. The vasoconstrictive effects of Evodiae Fructus were significantly inhibited by pretreatment with prazosin (adrenergic α1-receptor antagonist), BRL15572 [5-hydroxytryptamine (5-HT)1D antagonist], and ketanserin (5-HT2A antagonist), but its vasoconstrictive effects were not inhibited by pretreatment with SB216641 (5-HT1B antagonist) or propranolol (adrenergic β-receptor antagonist). These results suggest that Evodiae Fructus constricts rat aorta via adrenergic and serotonergic receptors. We also investigated the constrictive effects of synephrine on blood vessels. The vasoconstrictive effects of synephrine (1 × 10−7– 3 × 10−5 mol /L) were significantly inhibited by pretreatment with prazosin, BRL15572, and ketanserin. However, its constrictive effects were not inhibited by pretreatment with SB216641 and propranolol. The pA2 values of prazosin or ketanserin were nearly equal between Evodiae Fructus and synephrine. Because the constrictive effects of both Evodiae Fructus and synephrine were exerted via adrenergic α1-receptors and serotonergic (5-HT1D and 5-HT2A) receptors, synephrine may be one of the important components in the constrictive effects of Evodiae Fructus. Keywords:: Evodiae Fructus, synephrine, adrenergic α1, 5-hydroxytryptamine (5-HT)1D, 5-HT2A

Although cellular RNA is subjected to the same oxidative insults as DNA and other cellular macromolecules, oxidative damage to RNA has not been a major focus in investigations of the biological consequences of free radical damage. In fact, because it is largely single-stranded and its bases lack the protection of hydrogen bonding and binding by specific proteins, RNA may be more susceptible to oxidative insults than is DNA. Oxidative damage to protein-coding RNA or non-coding RNA will, in turn, potentially cause errors in proteins and/or dysregulation of gene expression. While less lethal than mutations in the genome, such sublethal insults to cells might be associated with underlying mechanisms of several chronic diseases, including neurodegenerative disease. Recently, oxidative RNA damage has been described in several neurodegenerative diseases including Alzheimer disease, Parkinson disease, dementia with Lewy bodies, and prion diseases. Of particular interest, oxidative RNA damage can be demonstrated in vulnerable neurons early in disease, suggesting that RNA oxidation may actively contribute to the onset of the disease. An increasing body of evidence suggests that, mechanistically speaking, the detrimental effects of oxidative RNA damage to protein synthesis are attenuated, at least in part, by the existence of protective mechanisms that prevent the incorporation of the damaged ribonucleotides into the translational machinery. Further investigations aimed at understanding the processing mechanisms related to oxidative RNA damage and its consequences may provide significant insights into the pathogenesis of neurodegenerative and other degenerative diseases and lead to better therapeutic strategies.

The effects of goshuyuto and chotosan, traditional Japanese medicines, on collagen-induced platelet aggregation were examined using guinea-pig blood. Goshuyuto at the concentration of 1,000 μg/mL inhibited collagen-induced platelet hyper-aggregation to the same degree as aspirin at the concentration of 100 μmol/L, but chotosan did not. Goshuyuto is composed of four medicinal herbs. Of them, aqueous extracts of Evodiae Fructus and Zingiberis Rhizoma inhibited platelet aggregation, but aqueous extracts of Zizyphi Fructus and Ginseng Radix did not. Two components of Zingiberis Rhizoma, 6-shogaol and 6-gingerol, also inhibited platelet aggregation. These results suggest that Evodiae Fructus and Zingiberis Rhizoma may play important roles in the anti-aggregation effects of goshuyuto and that 6-shogaol and 6-gingerol are among the active ingredients. Therefore, goshuyuto may ameliorate migraine by preventing the hyper-aggregation of platelets in migraine with aura. Keywords:: goshuyuto, Evodiae Fructus, Zingiberis Rhizoma, 6-shogaol, 6-gingerol

The 3a movement protein (MP) plays a central role in the movement of the RNA plant virus, Brome mosaic virus (BMV). To identify host factor genes involved in viral movement, a cDNA library of Nicotiana benthamiana, a systemic host for BMV, was screened with far-Western blotting using a recombinant BMV MP as probe. One positive clone encoded a protein with sequence similarity to the α chain of nascent-polypeptide-associated complex from various organisms, which is proposed to contribute to the fidelity of translocation of newly synthesized proteins. The orthologous gene from N. benthamiana was designated NbNACa1. The binding of NbNACa1 to BMV MP was confirmed in vivo with an agroinfiltration-immunoprecipitation assay. To investigate the involvement of NbNACa1 in BMV multiplication, NbNACa1-silenced (GSNAC) transgenic N. benthamiana plants were produced. Downregulation of NbNACa1 expression reduced virus accumulation in inoculated leaves but not in protoplasts. A microprojectile bombardment assay to monitor BMV-MP-assisted viral movement demonstrated reduced virus spread in GSNAC plants. The localization to the cell wall of BMV MP fused to green fluorescent protein was delayed in GSNAC plants. From these results, we propose that NbNACa1 is involved in BMV cell-to-cell movement through the regulation of BMV MP localization to the plasmodesmata.

BACKGROUND/AIMS: The GNAS1 locus encodes the Gas protein, which stimulates the formation of cycloadenosinemonophosphate (cAMP). The cAMP pathway mediates pleiotropic effects, including the regulation of apoptosis and proliferation. We have recently shown that TT genotypes of the single-nucleotide polymorphism T393C in the gene GNAS1 predict the clinical outcome of patients with various carcinomas. METHODS: Eighty-seven patients with intrahepatic cholangiocarcinoma (ICC) were retrospectively genotyped to elucidate a potential association between T393C genotypes and clinical outcome. RESULTS: ICCs of patients with homozygous TT genotypes revealed a higher proliferation rate and a lower apoptotic rate. Homozygous TT patients were at highest risk for cancer-related deaths (hazard ratio = 2.74; 95% confidence interval = 1.03-7.28) compared with C-allele carriers. Kaplan-Meier curves for disease-specific overall and local recurrence-free survival in a subgroup with Ro-resected ICC showed a significant association of T393 homozygosity with outcome, which was confirmed in multivariate Cox regression analysis. CONCLUSIONS: GNAS1 T393C is a novel independent host factor for disease progression in patients with ICC. Our finding that TT homozygosity (and not CC homozygosity) was associated with unfavorable clinical outcome points to the complex and differing functional effects induced by GNAS1 T393C polymorphism in various human carcinomas.

In eukaryotes, ARGONAUTE proteins (AGOs) associate with microRNAs (miRNAs), short interfering RNAs (siRNAs), and other classes of small RNAs to regulate target RNA or target loci. Viral infection in plants induces a potent and highly specific antiviral RNA silencing response characterized by the formation of virus-derived siRNAs. Arabidopsis thaliana has ten AGO genes of which AGO1, AGO2, and AGO7 have been shown to play roles in antiviral defense. A genetic analysis was used to identify and characterize the roles of AGO proteins in antiviral defense against Turnip mosaic virus (TuMV) in Arabidopsis. AGO1, AGO2 and AGO10 promoted anti-TuMV defense in a modular way in various organs, with AGO2 providing a prominent antiviral role in leaves. AGO5, AGO7 and AGO10 had minor effects in leaves. AGO1 and AGO10 had overlapping antiviral functions in inflorescence tissues after systemic movement of the virus, although the roles of AGO1 and AGO10 accounted for only a minor amount of the overall antiviral activity. By combining AGO protein immunoprecipitation with high-throughput sequencing of associated small RNAs, AGO2, AGO10, and to a lesser extent AGO1 were shown to associate with siRNAs derived from silencing suppressor (HC-Pro)-deficient TuMV-AS9, but not with siRNAs derived from wild-type TuMV. Co-immunoprecipitation and small RNA sequencing revealed that viral siRNAs broadly associated with wild-type HC-Pro during TuMV infection. These results support the hypothesis that suppression of antiviral silencing during TuMV infection, at least in part, occurs through sequestration of virus-derived siRNAs away from antiviral AGO proteins by HC-Pro. These findings indicate that distinct AGO proteins function as antiviral modules, and provide a molecular explanation for the silencing suppressor activity of HC-Pro.

An in situ approach was used to identify the oxidized RNA nucleoside 8-hydroxyguanosine (8OHG) in the frontal cortex of familial Alzheimer's disease (FAD) with a mutation in presenilin-1 (PS-1) or amyloid β protein precursor (AβPP) gene (n = 13, age 47–81 years). Neurons with marked 8OHG immunoreaction in the cytoplasm were widely distributed in the superior/middle frontal gyrus of FAD. Relative intensity measurements of neuronal 8OHG immunoreactivity showed that there was a significant increase in FAD compared with controls (n = 15, age 59–81 years), while there was no difference in relative 8OHG between the PS-1 and the AβPP FAD. Interestingly, a presymptomatic case carrying a PS-1 mutation showed a considerable level of relative 8OHG, and the increased levels of neuronal 8OHG in FAD were more prominent in cases with a lower percentage area of Aβ42 burden. These results suggest that oxidative stress is an early event involved in the pathological cascade of FAD.

8-hydroxy-2′-deoxyguanosine (8-OHdG) or 8-hydroxyguanosine (8-OHG), a product of oxidized DNA or RNA, is a good marker of oxidative cellular damage. In this study, we measured the 8-OHdG/8-OHG levels in the serum and cerebrospinal fluid (CSF) of patients with Parkinson's disease (PD) and multiple system atrophy (MSA). Compared to age-matched controls, the mean levels of serum 8-OHdG/8-OHG were significantly higher in PD (P < 0.0001). Although no gender differences were observed in the controls, the mean values of serum 8-OHdG/8-OHG were significantly higher in female PD cases (P < 0.005) than in male patients. 8-OHdG/8-OHG levels in CSF were also increased significantly in patients with PD and MSA, however, their relative values were generally much lower than those in the serum. Together with previous studies showing increased peripheral 8-OHdG levels in Alzheimer's disease and amyotrophic lateral sclerosis, the data presented here suggest that systemic DNA/RNA oxidation is commonly observed in neurodegenerative diseases. Our results also imply that female patients with PD show higher levels of oxidative stress, which may explain the faster progression of this disease in females.

We examined an idea that short-term cognition is transiently affected by a state of confusion in Zn2+ transport system due to a local increase in amyloid-β (Aβ) concentration. A single injection of Aβ (25 pmol) into the dentate gyrus affected dentate gyrus long-term potentiation (LTP) 1 h after the injection, but not 4 h after the injection. Simultaneously, 1-h memory of object recognition was affected when the training was performed 1 h after the injection, but not 4 h after the injection. Aβ-mediated impairments of LTP and memory were rescued in the presence of zinc chelators, suggesting that Zn2+ is involved in Aβ action. When Aβ was injected into the dentate gyrus, intracellular Zn2+ levels were increased only in the injected area in the dentate gyrus, suggesting that Aβ induces the influx of Zn2+ into cells in the injected area. When Aβ was added to hippocampal slices, Aβ did not increase intracellular Zn2+ levels in the dentate granule cell layer in ACSF without Zn2+, but in ACSF containing Zn2+. The increase in intracellular Zn2+ levels was inhibited in the presence of CaEDTA, an extracellular zinc chelator, but not in the presence of CNQX, an AMPA receptor antagonist. The present study indicates that Aβ-mediated Zn2+ influx into dentate granule cells, which may occur without AMPA receptor activation, transiently induces a short-term cognitive deficit. Extracellular Zn2+ may play a key role for transiently Aβ-induced cognition deficits.

BACKGROUND: The neuropsychological features and neuropathological progression patterns associated with rapidly evolving cognitive decline or dementia in Parkinson's disease (PD) remain to be elucidated. METHODS: Fifty-three PD patients without dementia were recruited to participate in a 3-year longitudinal cohort study. The patients were grouped according to the Clinical Dementia Rating (CDR). Group-wise comparisons were made with regard to demographic characteristics, motor symptoms, neuropsychological performances and 18F-fluorodeoxyglucose positron emission tomography. RESULTS: Patients who had memory-plus cognitive impairment (patients whose CDR was 0 at baseline and 0.5 in memory and other domains at follow-up, and those whose baseline CDR was 0.5 in memory and other domains) exhibited higher age at onset, visuoperceptual impairment, non-tremor-dominant motor disturbance, rapid symptomatic progression and posterior neocortical hypometabolism. In patients who were cognitively unimpaired and those who had memory-dominant cognitive impairment (patients whose CDR was 0 at baseline and 0.5 only in memory domain at follow-up, and those whose baseline CDR was 0.5 only in memory domain), the posterior neocortex was relatively unaffected until a later stage of the disease. CONCLUSIONS: These results suggest that visuoperceptual impairment and the early involvement of the posterior neocortex may be risk factors for rapid symptomatic progression and dementia in PD.

RationaleAppropriate ischemia models are required for successful studies of therapeutic angiogenesis. While collateral routes are known to be present within the innate vasculature, there are no reports describing the detailed vascular anatomy of the murine hindlimb. In addition, differences in the descriptions of anatomical names and locations in the literature impede understanding of the circulation and the design of hindlimb ischemia models. To understand better the collateral circulation in the whole hindlimb, clarification of all the feeding arteries of the hindlimb is required.ObjectiveThe aim of this study is to reveal the detailed arterial anatomy and collateral routes in murine hindlimb to enable the appropriate design of therapeutic angiogenesis studies and to facilitate understanding of the circulation in ischemia models.Methods and resultsArterial anatomy in the murine hindlimb was investigated by contrast-enhanced X-ray imaging and surgical dissection. The observed anatomy is shown in photographic images and in a schema. Previously unnoticed but relatively large arteries were observed in deep, cranial and lateral parts of the thigh. The data indicates that there are three collateral routes through the medial thigh, quadriceps femoris, and the biceps femoris muscles. Furthermore, anatomical variations were found at the origins of the three feeding arteries.ConclusionsThe detailed arterial anatomy of murine hindlimb and collateral routes deduced from the anatomy are described. Limitations on designs of ischemia models in view of anatomical variations are proposed. These observations will contribute to the development of animal studies of therapeutic angiogenesis using murine hindlimb ischemia models.

The RNA exosome is a multi-subunit complex that is responsible for 3' to 5' degradation and processing of cellular RNA. Rrp44/Dis3 is the catalytic center of the exosome in yeast and humans. However, the role of Rrp44/Dis3 homologs in plants is still unidentified. Here, we show that Arabidopsis AtRRP44A is the functional homolog of Rrp44/Dis3, is essential for plant viability and is required for RNA processing and degradation. We characterized AtRRP44A and AtRRP44B/SOV, two predicted Arabidopsis Rrp44/Dis3 homologs. AtRRP44A could functionally replace S. cerevisiae Rrp44/Dis3, but AtRRP44B/SOV could not. rrp44a knock-down mutants showed typical phenotypes of exosome function deficiency, 5.8S rRNA 3' extension and rRNA maturation by-product over-accumulation, but rrp44b mutants did not. Conversely, AtRRP44B/SOV mutants showed elevated levels of a selected mRNA, on which rrp44a did not have detectable effects. Although T-DNA insertion mutants of AtRRP44B/SOV had no obvious phenotype, those of AtRRP44A showed defects in female gametophyte development and early embryogenesis. These results indicate that AtRRP44A and AtRRP44B/SOV have independent roles for RNA turnover in plants.

Zinc homeostasis in the brain is associated with the etiology and manifestation of epileptic seizures. Adult Noda epileptic rats (NER, >12-week-old) exhibit spontaneously generalized tonic-clonic convulsion about once a day. To pursue the involvement of synaptic Zn(2+) signal in susceptibility to spontaneous seizures, in the present study, the effect of zinc chelators on epileptogenesis was examined using adult NER. Clioquinol (CQ) and TPEN are lipophilic zinc chelotors, transported into the brain and reduce the levels of synaptic Zn(2+). The incidence of tonic-clonic convulsion was markedly increased after i.p. injection of CQ (30-100 mg/kg) and TPEN (1 mg/kg). The basal levels of extracellular Zn(2+) measured by ZnAF-2 were decreased before tonic-clonic convulsion was induced with zinc chelators. The hippocampal electroencephalograms during CQ (30 mg/kg)-induced convulsions were similar to those during sound-induced convulsions in NER reported previously. Exocytosis of hippocampal mossy fibers, which was measured with FM4-64, was significantly increased in hippocampal slices from CQ-injected NER that did not show tonic-clonic convulsion yet. These results indicate that the abnormal excitability of mossy fibers is induced prior to epileptic seizures by injection of zinc chelators into NER. The incidence of tonic-clonic convulsion induced with CQ (30 mg/kg) was significantly reduced by co-injection with aminooxyacetic acid (5-10 mg/kg), an anticonvulsant drug enhancing GABAergic activity, which did not affect locomotor activity. The present paper demonstrates that the abnormal excitability in the brain, especially in mossy fibers, which is potentially associated with the insufficient GABAergic neuron activity, may be a factor to reduce the threshold for epileptogenesis in NER.

Dietary zinc deficiency increases glucocorticoid secretion from the adrenal cortex via enhanced hypothalamo-pituitary-adrenocortical (HPA) axis activity and induces neuropsychological symptoms, i.e., behavioral abnormality. Behavioral abnormality is due to the increase in glucocorticoid secretion rather than disturbance of brain zinc homeostasis, which occurs after the increase in glucocorticoid secretion. A major target of glucocorticoids is the hippocampus and their actions are often associated with disturbance of glutamatergic neurotransmission, which may be linked to behavioral abnormality, such as depressive symptoms and aggressive behavior under zinc deficiency. Glucocorticoid-mediated disturbance of glutamatergic neurotransmission in the hippocampus is also involved in the pathophysiology of, not only psychiatric disorders, such as depression, but also neurodegenerative disorders, e.g., Alzheimer’s disease. The evidence suggests that zinc-deficient animals are models for behavioral and psychological symptoms of dementia (BPSD), as well as depression. To understand validity to apply zinc-deficient animals as a behavioral abnormality model, this paper deals with the effect of antidepressive drugs and herbal medicines on hippocampal dysfunctions and behavioral abnormality, which are induced by enhanced HPA axis activity under dietary zinc deficiency.

The attentional set-shifting deficit that has been observed in Parkinson's disease (PD) has long been considered neuropsychological evidence of the involvement of meso-prefrontal and prefrontal-striatal circuits in cognitive flexibility. However, recent studies have suggested that non-dopaminergic, posterior cortical pathologies may also contribute to this deficit. Although several neuroimaging studies have addressed this issue, the results of these studies were confounded by the use of tasks that required other cognitive processes in addition to set-shifting, such as rule learning and working memory. In this study, we attempted to identify the neural correlates of the attentional set-shifting deficit in PD using a compound letter task and 18F-fluoro-deoxy-glucose (FDG) positron emission tomography during rest. Shift cost, which is a measure of attentional set-shifting ability, was significantly correlated with hypometabolism in the right dorsolateral prefrontal cortex, including the putative human frontal eye field. Our results provide direct evidence that dysfunction in the dorsolateral prefrontal cortex makes a primary contribution to the attentional set-shifting deficit that has been observed in PD patients.

Zinc is released from glutamatergic (zincergic) neuron terminals in the hippocampus, followed by the increase in Zn2+ concentration in the intracellular (cytosol) compartment, as well as that in the extracellular compartment. The increase in Zn2+ concentration in the intracellular compartment during synaptic excitation is mainly due to Zn2+ influx through calcium-permeable channels and serves as Zn2+ signaling as well as the case in the extracellular compartment. Synaptic Zn2+ homeostasis is important for glutamate signaling and altered under numerous pathological processes such as Alzheimer's disease. Synaptic Zn2+ homeostasis might be altered in old age, and this alteration might be involved in the pathogenesis and progression of Alzheimer's disease; Zinc may play as a key-mediating factor in the pathophysiology of Alzheimer's disease. This paper summarizes the role of Zn2+ signaling in glutamate excitotoxicity, which is involved in Alzheimer's disease, to understand the significance of synaptic Zn2+ homeostasis in the pathophysiology of Alzheimer's disease.

Many neurodegenerative diseases share a common pathological feature: the deposition of amyloid-like fibrils composed of misfolded proteins. Emerging evidence suggests that these proteins may spread from cell-to-cell and encourage the propagation of neurodegeneration in a prion-like manner. Here, we demonstrated that α-synuclein (αSYN), a principal culprit for Lewy pathology in Parkinson's disease (PD), was present in endosomal compartments and detectably secreted into the extracellular milieu. Unlike prion protein, extracellular αSYN was mainly recovered in the supernatant fraction rather than in exosome-containing pellets from the neuronal culture medium and cerebrospinal fluid. Surprisingly, impaired biogenesis of multivesicular body (MVB), an organelle from which exosomes are derived, by dominant-negative mutant vacuolar protein sorting 4 (VPS4) not only interfered with lysosomal targeting of αSYN but facilitated αSYN secretion. The hypersecretion of αSYN in VPS4-defective cells was efficiently restored by the functional disruption of recycling endosome regulator Rab11a. Furthermore, both brainstem and cortical Lewy bodies in PD were found to be immunoreactive for VPS4. Thus, VPS4, a master regulator of MVB sorting, may serve as a determinant of lysosomal targeting or extracellular secretion of αSYN and thereby contribute to the intercellular propagation of Lewy pathology in PD.

The translocation of synaptic Zn(2+) to the cytosolic compartment has been studied to understand Zn(2+) neurotoxicity in neurological diseases. However, it is unknown whether the moderate increase in Zn(2+) in the cytosolic compartment affects memory processing in the hippocampus. In the present study, the moderate increase in cytosolic Zn(2+) in the hippocampus was induced with clioquinol (CQ), a zinc ionophore. Zn(2+) delivery by Zn-CQ transiently attenuated CA1 long-term potentiation (LTP) in hippocampal slices prepared 2 h after i.p. injection of Zn-CQ into rats, when intracellular Zn(2+) levels was transiently increased in the CA1 pyramidal cell layer, followed by object recognition memory deficit. Object recognition memory was transiently impaired 30 min after injection of ZnCl(2) into the CA1, but not after injection into the dentate gyrus that did not significantly increase intracellular Zn(2+) in the granule cell layer of the dentate gyrus. Object recognition memory deficit may be linked to the preferential increase in Zn(2+) and/or the preferential vulnerability to Zn(2+) in CA1 pyramidal neurons. In the case of the cytosolic increase in endogenous Zn(2+) in the CA1 induced by 100 mM KCl, furthermore, object recognition memory was also transiently impaired, while ameliorated by co-injection of CaEDTA to block the increase in cytosolic Zn(2+). The present study indicates that the transient increase in cytosolic Zn(2+) in CA1 pyramidal neurons reversibly impairs object recognition memory.