Diversity of T Cells Restricted by the MHC Class I-Related Molecule MR1 Facilitates Differential Antigen Recognition.

A characteristic of mucosal-associated invariant T (MAIT) cells is the expression of TRAV1-2(+) T cell receptors (TCRs) that are activated by riboflavin metabolite-based antigens (Ag) presented by the MHC-I related molecule, MR1. Whether the MR1-restricted T cell repertoire and associated Ag responsiveness extends beyond these cells remains unclear. Here, we describe MR1 autoreactivity and folate-derivative reactivity in a discrete subset of TRAV1-2(+) MAIT cells. This recognition was attributable to CDR3ß loop-mediated effects within a consensus TRAV1-2(+) TCR-MR1-Ag footprint. Furthermore, we have demonstrated differential folate- and riboflavin-derivative reactivity by a diverse population of "atypical" TRAV1-2(-) MR1-restricted T cells. We have shown that TRAV1-2(-) T cells are phenotypically heterogeneous and largely distinct from TRAV1-2(+) MAIT cells. A TRAV1-2(-) TCR docks more centrally on MR1, thereby adopting a markedly different molecular footprint to the TRAV1-2(+) TCR. Accordingly, diversity within the MR1-restricted T cell repertoire leads to differing MR1-restricted Ag specificity.

The classical D1 dopamine receptor antagonist SCH23390 is a functional sigma-1 receptor allosteric modulator.

SCH23390 is a widely used D1 dopamine receptor (D1R) antagonist that also elicits some D1R-independent effects. We previously found that the benzazepine, SKF83959, an analog of SCH23390, produces positive allosteric modulation of the Sigma-1 receptor (Sig1R). SCH23390 does not bind to the orthodoxic site of Sig1R but enhances the binding of 3H (+)-pentazocine to Sig1R. In this study, we investigated whether SCH23390 functions as an allosteric modulator of Sig1R. We detected increased Sig1R dissociation from binding immunoglobulin protein (BiP) and translocation of Sig1R to the plasma membrane in response to SCH23390 in transfected HEK293T and SH-SY5Y cells, respectively. Activation of Sig1R by SCH23390 was further confirmed by inhibition of GSK3ß activity in a time- and dose-dependent manner; this effect was blocked by pretreatment with the Sig1R antagonist, BD1047, and by knockdown of Sig1R. SCH23390 also inhibited GSK3ß in wild-type mice but not in Sig1R knockout mice. Finally, we showed that SCH23390 allosterically modulated the effect of the Sig1R agonist SKF10047 on inhibition of GSK3ß. This positive allosteric effect of SCH23390 was further confirmed via promotion of neuronal protection afforded by SKF10047 in primary cortical neurons challenged with MPP+. These results provide the first evidence that SCH23390 elicits functional allosteric modulation of Sig1R. Our findings not only reveal novel pharmacological effects of SCH23390 but also indicate a potential mechanism for SCH23390-mediated D1R-independent effects. Therefore, attention should be paid to these Sig1R-mediated effects when explaining pharmacological responses to SCH23390.

Adolescence as a critical period for nandrolone-induced muscular strength in relation to abuse liability, alone and in conjunction with morphine, using accumbal dopamine efflux in freely moving rats.

Nandrolone, an anabolic androgenic steroid, is included in the prohibited list of the World Anti-Doping Agency. Drugs of abuse activate brain dopamine neurons and nandrolone has been suspected of inducing dependence. Accordingly, possible critical periods for the effects of nandrolone on muscular strength and dopaminergic activity have been investigated, including the effects of chronically administered nandrolone alone and on morphine-induced increases in dopamine efflux in the nucleus accumbens. Six- or 10-week-old male Sprague-Dawley rats were used. Treatment with nandrolone was initiated in adolescent (6-week-old) and young adult (10-week-old) rats. Nandrolone (5.0 mg/kg s.c.) or sesame oil vehicle was given once daily, on six consecutive days per week, for 3 weeks and then once per day for 4 consecutive days. Nandrolone enhanced the developmental increase in grip strength of 6- but not 10-week-old rats, without altering the developmental increase in body weight of either age group. Using in vivo microdialysis in freely moving 6-week-old rats given nandrolone for 4 weeks, basal accumbal dopamine efflux was unaltered, while the increase in dopamine efflux induced by acute administration of morphine (1.0 mg/kg s.c.) was reduced. The present study provides in vivo evidence that adolescence constitutes a critical period during which repeated administration of nandrolone enhances increases in muscular strength without influencing increases in body weight. Though repeated administration of nandrolone during this period of adolescence did not stimulate in vivo mesolimbic dopaminergic activity, it disrupted stimulation by an opioid, the drug class that is most commonly coabused with nandrolone.

Dysbindin-1A modulation of astrocytic dopamine and basal ganglia dependent behaviors relevant to schizophrenia.

The mechanisms underlying the dichotomic cortical/basal ganglia dopaminergic abnormalities in schizophrenia are unclear. Astrocytes are important non-neuronal modulators of brain circuits, but their role in dopaminergic system remains poorly explored. Microarray analyses, immunohistochemistry, and two-photon laser scanning microscopy revealed that Dys1 hypofunction increases the reactivity of astrocytes, which express only the Dys1A isoform. Notably, behavioral and electrochemical assessments in mice selectively lacking the Dys1A isoform unraveled a more prominent impact of Dys1A in behavioral and dopaminergic/D2 alterations related to basal ganglia, but not cortical functioning. Ex vivo electron microscopy and protein expression analyses indicated that selective Dys1A disruption might alter intracellular trafficking in astrocytes, but not in neurons. In agreement, Dys1A disruption only in astrocytes resulted in decreased motivation and sensorimotor gating deficits, increased astrocytic dopamine D2 receptors and decreased dopaminergic tone within basal ganglia. These processes might have clinical relevance because the caudate, but not the cortex, of patients with schizophrenia shows a reduction of the Dys1A isoform. Therefore, we started to show a hitherto unknown role for the Dys1A isoform in astrocytic-related modulation of basal ganglia behavioral and dopaminergic phenotypes, with relevance to schizophrenia.

In vivo microdialysis reveals that blockade of accumbal orexin OX2 but not OX1 receptors enhances dopamine efflux in the nucleus accumbens of freely moving rats.

The nucleus accumbens contain orexinergic neural inputs and orexin OX1 - and OX2 -receptors. Behavioural studies suggest that accumbal orexin receptors modulate accumbal dopaminergic activity-dependent locomotion in rats. We studied the effects of intra-accumbal injection of orexin receptor ligands on accumbal extracellular dopamine levels in freely moving rats, using in vivo microdialysis and analysed the roles of OX1 - and OX2 -receptors in the regulation of basal accumbal dopamine efflux. The orexin receptor ligands were applied intra-accumbally though a microinjection needle attached with a dialysis probe. Neither the nonselective OX1 - and OX2 -receptor agonist orexin-A nor the preferential OX2 -receptor agonist orexin-B (500.0 pg and 5.0 ng) altered accumbal dopamine levels. The nonselective OX1 - and OX2 -receptor antagonist MK-4305 (suvorexant, 500.0 pg, 2.5 and 5.0 ng) enhanced dopamine efflux. A 2-h tetrodotoxin infusion into nucleus accumbens through the probe or co-administration of orexin-A (500.0 pg) strongly inhibited MK-4305 (5.0 ng)-induced accumbal dopamine efflux. The selective OX2 -receptor antagonist EMPA (90.0 and 900.0 pg, 9.0 ng) increased dopamine efflux. Intra-accumbal infusion of tetrodotoxin abolished EMPA (9.0 ng)-induced dopamine efflux. The selective OX1 -receptor antagonist SB-334867 (10.0 and 20.0 ng) failed to alter dopamine efflux. Co-administration of orexin-B (500.0 pg) inhibited both EMPA (9.0 ng)- and MK-4305 (5.0 ng)-induced dopamine efflux. Intraperitoneal injection of MK-4305 (10.0 mg/kg) did not affect accumbal dopamine efflux. The present study provides in vivo neuropharmacological evidence that accumbal OX2 - but not OX1 -receptors exert inhibitory regulation of basal accumbal dopamine efflux and that blockade of accumbal OX2 -receptors enhances dopamine efflux in nucleus accumbens of freely moving rats.

Gender, age at onset, and duration of being ill as predictors for the long-term course and outcome of schizophrenia: an international multicenter study.

BACKGROUND: The aim of the current study was to explore the effect of gender, age at onset, and duration on the long-term course of schizophrenia. METHODS: Twenty-nine centers from 25 countries representing all continents participated in the study that included 2358 patients aged 37.21 ± 11.87 years with a DSM-IV or DSM-5 diagnosis of schizophrenia; the Positive and Negative Syndrome Scale as well as relevant clinicodemographic data were gathered. Analysis of variance and analysis of covariance were used, and the methodology corrected for the presence of potentially confounding effects. RESULTS: There was a 3-year later age at onset for females (P < .001) and lower rates of negative symptoms (P < .01) and higher depression/anxiety measures (P < .05) at some stages. The age at onset manifested a distribution with a single peak for both genders with a tendency of patients with younger onset having slower advancement through illness stages (P = .001). No significant effects were found concerning duration of illness. DISCUSSION: Our results confirmed a later onset and a possibly more benign course and outcome in females. Age at onset manifested a single peak in both genders, and surprisingly, earlier onset was related to a slower progression of the illness. No effect of duration has been detected. These results are partially in accord with the literature, but they also differ as a consequence of the different starting point of our methodology (a novel staging model), which in our opinion precluded the impact of confounding effects. Future research should focus on the therapeutic policy and implications of these results in more representative samples.

Dysregulation of iron homeostasis and methamphetamine reward behaviors in Clk1-deficient mice.

Chronic administration of methamphetamine (METH) leads to physical and psychological dependence. It is generally accepted that METH exerts rewarding effects via competitive inhibition of the dopamine transporter (DAT), but the molecular mechanism of METH addiction remains largely unknown. Accumulating evidence shows that mitochondrial function is important in regulation of drug addiction. In this study,  we investigated the role of Clk1, an essential mitochondrial hydroxylase for ubiquinone (UQ), in METH reward effects. We showed that Clk1+/- mutation significantly suppressed METH-induced conditioned place preference (CPP), accompanied by increased expression of DAT in plasma membrane of striatum and hippocampus due to Clk1 deficiency-induced inhibition of DAT degradation without influencing de novo synthesis of DAT. Notably, significantly decreased iron content in striatum and hippocampus was evident in both Clk1+/- mutant mice and PC12 cells with Clk1 knockdown. The decreased iron content was attributed to increased expression of iron exporter ferroportin 1 (FPN1) that was associated with elevated expression of hypoxia-inducible factor-1α (HIF-1α) in response to Clk1 deficiency both in vivo and in vitro. Furthermore, we showed that iron played a critical role in mediating Clk1 deficiency-induced alteration in DAT expression, presumably via upstream HIF-1α. Taken together, these data demonstrated that HIF-1α-mediated changes in iron homostasis are involved in the Clk1 deficiency-altered METH reward behaviors.

Systematic epidemiological and clinical comparisons across all 12 DSM-IV psychotic diagnoses in the Cavan-Monaghan First Episode Psychosis Study (CAMFEPS).

BACKGROUND: Research on psychotic illness is loosening emphasis on diagnostic stringency in favour of including a more dimensionally based conceptualization of psychopathology and pathobiology. However, to clarify these notions requires investigation of the full scope of psychotic diagnoses. METHODS: The Cavan-Monaghan First Episode Psychosis Study ascertained cases of first episode psychosis across all 12 DSM-IV psychotic diagnoses via all routes to care: public, private or forensic; home-based, outpatient or inpatient. There was no arbitrary upper age cut-off and minimal impact of factors associated with variations in social milieu, ethnicity or urbanicity. Cases were evaluated epidemiologically and assessed for psychopathology, neuropsychology, neurology, antecedent factors, insight and quality of life. RESULTS: Among 432 cases, the annual incidence of any DSM-IV psychotic diagnosis was 34.1/100 000 of population and encompassed functional psychotic diagnoses, substance-induced psychopathology and psychopathology due to general medical conditions, through to psychotic illness that defied contemporary diagnostic algorithms. These 12 DSM-IV diagnostic categories, including psychotic disorder not otherwise specified, showed clinical profiles that were consistently more similar than distinct. CONCLUSIONS: There are considerable similarities and overlaps across a broad range of diagnostic categories in the absence of robust discontinuities between them. Thus, psychotic illness may be of such continuity that it cannot be fully captured by operational diagnostic algorithms that, at least in part, assume discontinuities. This may reflect the impact of diverse factors each of which acts on one or more overlapping components of a common, dysfunctional neuronal network implicated in the pathobiology of psychotic illness.

Modeling psychological function in patients with schizophrenia with the PANSS: an international multi-center study.

BACKGROUND: The aim of the current study was to explore the changing interrelationships among clinical variables through the stages of schizophrenia in order to assemble a comprehensive and meaningful disease model. METHODS: Twenty-nine centers from 25 countries participated and included 2358 patients aged 37.21 ± 11.87 years with schizophrenia. Multiple linear regression analysis and visual inspection of plots were performed. RESULTS: The results suggest that with progression stages, there are changing correlations among Positive and Negative Syndrome Scale factors at each stage and each factor correlates with all the others in that particular stage, in which this factor is dominant. This internal structure further supports the validity of an already proposed four stages model, with positive symptoms dominating the first stage, excitement/hostility the second, depression the third, and neurocognitive decline the last stage. CONCLUSIONS: The current study investigated the mental organization and functioning in patients with schizophrenia in relation to different stages of illness progression. It revealed two distinct "cores" of schizophrenia, the "Positive" and the "Negative," while neurocognitive decline escalates during the later stages. Future research should focus on the therapeutic implications of such a model. Stopping the progress of the illness could demand to stop the succession of stages. This could be achieved not only by both halting the triggering effect of positive and negative symptoms, but also by stopping the sensitization effect on the neural pathways responsible for the development of hostility, excitement, anxiety, and depression as well as the deleterious effect on neural networks responsible for neurocognition.

Structural alterations in brainstem, basal ganglia and thalamus associated with parkinsonism in schizophrenia spectrum disorders.

The relative roles of brainstem, thalamus and striatum in parkinsonism in schizophrenia spectrum disorder (SSD) patients are largely unknown. To determine whether topographical alterations of the brainstem, thalamus and striatum contribute to parkinsonism in SSD patients, we conducted structural magnetic resonance imaging (MRI) of SSD patients with (SSD-P, n = 35) and without (SSD-nonP, n = 64) parkinsonism, as defined by a Simpson and Angus Scale (SAS) total score of ≥ 4 and < 4, respectively, in comparison with healthy controls (n = 20). FreeSurfer v6.0 was used for segmentation of four brainstem regions (medulla oblongata, pons, superior cerebellar peduncle and midbrain), caudate nucleus, putamen and thalamus. Patients with parkinsonism had significantly smaller medulla oblongata (p = 0.01, false discovery rate (FDR)-corrected) and putamen (p = 0.02, FDR-corrected) volumes when compared to patients without parkinsonism. Across the entire patient sample (n = 99), significant negative correlations were identified between (a) medulla oblongata volumes and both SAS total (p = 0.034) and glabella-salivation (p = 0.007) scores, and (b) thalamic volumes and both SAS total (p = 0.033) and glabella-salivation (p = 0.007) scores. These results indicate that brainstem and thalamic structures as well as basal ganglia-based motor circuits play a crucial role in the pathogenesis of parkinsonism in SSD.

Early intervention in psychosis: health economic evaluation using the net benefit approach in a real-world setting.

BACKGROUND: Early intervention in psychosis is a complex intervention, usually delivered in a specialist stand-alone setting, which aims to improve outcomes for people with psychosis. Previous studies have been criticised because the control used did not accurately reflect actual practice. AIMS: To evaluate the cost-effectiveness of early intervention by estimating the incremental net benefit (INB) of an early-intervention programme, delivered in a real-world setting. INB measures the difference in monetary terms between alternative interventions. METHOD: Two contemporaneous incidence-based cohorts presenting with first-episode psychosis, aged 18-65 years, were compared. Costs and outcomes were measured over 1 year. The main outcome was avoidance of a relapse that required admission to hospital or home-based treatment. RESULTS: From the health sector perspective, the probability that early intervention was cost-effective was 0.77. The INB was €2465 per person (95% CI - €4418 to €9347) when society placed a value of €6000, the cost of an in-patient relapse, on preventing a relapse requiring admission or home care. Following adjustment, the probability that early intervention was cost-effective was 1, and the INB to the health sector was €3105 per person (95% CI -€8453 to €14 663). From a societal perspective, the adjusted probability that early intervention was cost-effective was 1, and the INB was €19 928 per person (95% CI - €2075 to €41 931). CONCLUSIONS: Early intervention has a modest INB from the health sector perspective and a large INB from the societal perspective. The perspective chosen is critical when presenting results of an economic evaluation of a complex intervention.

Psychosis in Parkinson's disease and parkinsonism in antipsychotic-naive schizophrenia spectrum psychosis: clinical, nosological and pathobiological challenges.

Following the formulation of operational criteria for the diagnosis of psychosis in Parkinson's disease, a neurodegenerative disorder, the past decade has seen increasing interest in such nonmotor psychopathology that appears to be independent of dopaminergic therapy. Similarly, there has been a resurgence of interest in motor aspects of the neurodevelopmental disorder of schizophrenia, including spontaneous parkinsonism that appears to be independent of antipsychotic treatment. This review first addresses the clinical and nosological challenges of these superficially paradoxical insights and then considers pathobiological challenges. It proposes that diverse modes of disturbance to one or more element(s) in a cortical-striatal-thalamocortical neuronal network, whether neurodegenerative or neurodevelopmental, can result in movement disorder, psychosis or both. It then proposes that time- and site-dependent dysfunction in such a neuronal network may be a generic substrate for the emergence of psychosis not only in Parkinson's disease and schizophrenia-spectrum disorders but also in other neuropsychiatric disorders in which psychosis, and sometimes movement disorders, can be encountered; these include substance abuse, cerebrovascular disease, cerebral trauma, cerebral neoplasia, epilepsy, Huntington's disease, frontotemporal dementia, Alzheimer's disease and multiple sclerosis.

Development and characterization of an inducible Dicer conditional knockout mouse model of Parkinson's disease: validation of the antiparkinsonian effects of a sigma-1 receptor agonist and dihydromyricetin.

Parkinson's disease (PD) is a common neurodegenerative disease characterized by motor impairment and progressive loss of dopamine (DA) neurons. At present, the acute application of neurotoxic drugs such as 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) and 6-hydroxydopamine (6-OHDA) are commonly used to simulate the pathology of PD; however, it is difficult to induce the progressive pathogenesis of PD with these models. In this study, we employed DAT promoter-mediated Cre transgenic mice to establish tamoxifen-inducible Dicer conditional knockout (cKO) mice in an effort to mimic the progressive loss of DA neurons and the development of PD-like behavioral phenotypes. The results showed that Dicer cKO mice exhibited progressive loss of DA neurons in the substantia nigra (SN) following tamoxifen administration. Significant DA loss was observed 6 weeks after tamoxifen administration; accordingly, progressive motor function impairment was also observed. We also found that a significant neuroinflammatory response, as evidenced by microglial proliferation, another hallmark of PD pathogenesis, accompanied the loss of DA neurons. The acute application of levo-DOPA (L-DOPA) relieved the PD-like motor impairments in Dicer cKO mice to exert its antiparkinsonian action, indicating that the model can be used to evaluate the antiparkinsonian efficacy of PD drugs. To further elucidate the potential application of this novel PD animal model for PD drug development, we employed the powerful neuroprotective agent dihydromyricetin (DHM) (10 mg/kg) and the selective sigma-1 receptor agonist PRE-084 (1 mg/kg), both of which were previously shown to produce antiparkinsonian effects. The results indicated that the chronic administration of either DHM or PRE-084 attenuated the Dicer cKO-induced loss of DA neurons and motor impairments, although the two drugs acted through different mechanisms. These data indicate that the Dicer cKO mouse model may be a useful model for investigating the pathological development of PD and intervention-mediated changes. In conclusion, this transgenic mouse model appears to simulate the progressive pathogenesis of PD and may be a potentially useful model for PD drug discovery.

Dopaminergic mechanisms in the lateral hypothalamus regulate feeding behavior in association with neuropeptides.

This study investigated dopaminergic function in the lateral hypothalamus (LH) in the regulation of feeding behavior. Refeeding increased dopamine levels in the LH. Glucose injection also increased dopamine levels in the LH. When the retrograde tracer Fluoro-Gold (FG) was injected into the LH, FG-positive cells were found in the ventral tegmental area (VTA) and the substantia nigra pars compacta (SNC), which were mostly tyrosine hydroxylase-positive. Injection of the dopamine D1 receptor agonist SKF 38393, but not the antagonist SCH 23390, into the LH increased food intake. Similarly, injection of the dopamine D2 receptor agonist quinpirole, but not the antagonist l-sulpiride, into the LH increased food intake. The effect of each agonist was blocked by its respective antagonist. Furthermore, injection of quinpirole, but not SKF 38393, decreased the mRNA level of preproorexin. In addition, injection of SKF 38393 decreased the mRNA levels of neuropeptide Y and agouti-related peptide, whereas the injection of quinpirole increased the mRNA level of proopiomelanocortin. These results indicate that food intake activates dopamine neurons projecting from the VTA/SNC to the LH through an increase in blood glucose levels, which terminates food intake by stimulation of dopamine D1 and D2 receptors. It is also possible that stimulation of dopamine D1 and D2 receptors in the LH inhibits feeding behavior through different neuropeptides.

Staging of Schizophrenia With the Use of PANSS: An International Multi-Center Study.

INTRODUCTION: A specific clinically relevant staging model for schizophrenia has not yet been developed. The aim of the current study was to evaluate the factor structure of the PANSS and develop such a staging method. METHODS: Twenty-nine centers from 25 countries contributed 2358 patients aged 37.21 ± 11.87 years with schizophrenia. Analysis of covariance, Exploratory Factor Analysis, Discriminant Function Analysis, and inspection of resultant plots were performed. RESULTS: Exploratory Factor Analysis returned 5 factors explaining 59% of the variance (positive, negative, excitement/hostility, depression/anxiety, and neurocognition). The staging model included 4 main stages with substages that were predominantly characterized by a single domain of symptoms (stage 1: positive; stages 2a and 2b: excitement/hostility; stage 3a and 3b: depression/anxiety; stage 4a and 4b: neurocognition). There were no differences between sexes. The Discriminant Function Analysis developed an algorithm that correctly classified >85% of patients. DISCUSSION: This study elaborates a 5-factor solution and a clinical staging method for patients with schizophrenia. It is the largest study to address these issues among patients who are more likely to remain affiliated with mental health services for prolonged periods of time.

In vivo neurochemical evidence that stimulation of accumbal GABAA and GABAB receptors each reduce acetylcholine efflux without affecting dopamine efflux in the nucleus accumbens of freely moving rats.

Cholinergic neurons in the nucleus accumbens contain GABAA and GABAB receptors that are thought to inhibit neural activity. We analyzed the roles of GABAA and GABAB receptors in regulating accumbal acetylcholine efflux of freely moving rats using in vivo microdialysis. The effects of GABA receptor ligands on the accumbal dopamine efflux were also analyzed because accumbal cholinergic and dopaminergic neurons could mutually interact. Drugs were applied intracerebrally through the dialysis probe. Doses of compounds indicate total amount administered (mol) during 30-60 min infusions. To monitor basal acetylcholine, a low concentration of physostigmine (50 nM) was added to the perfusate. GABAA receptor agonist muscimol (3 and 30 pmol) induced a dose-related decrease in accumbal acetylcholine. GABAB receptor agonist baclofen (30 and 300 pmol) also produced a dose-related decrease in acetylcholine. GABAA receptor antagonist bicuculline (60 pmol) which failed to alter baseline acetylcholine counteracted the muscimol (30 pmol)-induced decrease in acetylcholine. GABAB receptor antagonist 2-hydroxysaclofen (12 nmol) which failed to change baseline acetylcholine, counteracted the baclofen (300 pmol)-induced decrease in acetylcholine. Neither muscimol (30 pmol) nor baclofen (300 pmol) which reduced accumbal acetylcholine altered baseline accumbal dopamine. Neither bicuculline (60 pmol) nor 2-hydroxysaclofen (12 nmol) also affected the baseline dopamine. These results show that GABAA and GABAB receptors each exert inhibitory roles in the regulation of accumbal cholinergic neural activity. The present results also provides in vivo neurochemical evidence that stimulation of GABAA and GABAB receptors each reduce acetylcholine efflux without affecting dopamine efflux in the nucleus accumbens of freely moving rats.

Activation of AMPK/mTORC1-Mediated Autophagy by Metformin Reverses Clk1 Deficiency-Sensitized Dopaminergic Neuronal Death.

The autophagy-lysosome pathway (ALP) plays a critical role in the pathology of Parkinson's disease (PD). Clk1 (coq7) is a mitochondrial hydroxylase that is essential for coenzyme Q (ubiquinone) biosynthesis. We have reported previously that Clk1 regulates microglia activation via modulating microglia metabolic reprogramming, which contributes to dopaminergic neuronal survival. This study explores the direct effect of Clk1 on dopaminergic neuronal survival. We demonstrate that Clk1 deficiency inhibited dopaminergic neuronal autophagy in cultured MN9D dopaminergic neurons and in the substantia nigra pars compacta of Clk+/- mutant mice and consequently sensitized dopaminergic neuron damage and behavioral defects. These mechanistic studies indicate that Clk1 regulates the AMP-activated protein kinase (AMPK)/rapamycin complex 1 pathway, which in turn impairs the ALP and TFEB nuclear translocation. As a result, Clk1 deficiency promotes dopaminergic neuronal damage in vivo and in vitro, which ultimately contributes to sensitizing 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced dopaminergic neuronal death and behavioral impairments in Clk1-deficient mice. Moreover, we found that activation of autophagy by the AMPK activator metformin increases dopaminergic neuronal survival in vitro and in the MPTP-induced PD model in Clk1 mutant mice. These results reveal that Clk1 plays a direct role in dopaminergic neuronal survival via regulating ALPs that may contribute to the pathologic development of PD. Modulation of Clk1 activity may represent a potential therapeutic target for PD.

Clk1 deficiency promotes neuroinflammation and subsequent dopaminergic cell death through regulation of microglial metabolic reprogramming.

Clock (Clk)1/COQ7 is a mitochondrial hydroxylase that is necessary for the biosynthesis of ubiquinone (coenzyme Q or UQ). Here, we investigate the role of Clk1 in neuroinflammation and consequentially dopaminergic (DA) neuron survival. Reduced expression of Clk1 in microglia enhanced the LPS-induced proinflammatory response and promoted aerobic glycolysis. Inhibition of glycolysis abolished Clk1 deficiency-induced hypersensitivity to the inflammatory stimulation. Mechanistic studies demonstrated that mTOR/HIF-1α and ROS/HIF-1α signaling pathways were involved in Clk1 deficiency-induced aerobic glycolysis. The increase in neuronal cell death was observed following treatment with conditioned media from Clk1 deficient microglia. Increased DA neuron loss and microgliosis were observed in Clk1+/- mice after treatment with MPTP, a rodent model of Parkinson's disease (PD). This increase in DA neuron loss was due to an exacerbated microglial inflammatory response, rather than direct susceptibility of Clk1+/- DA cells to MPP+, the active species of MPTP. Exaggerated expressions of proinflammatory genes and loss of DA neurons were also observed in Clk1+/- mice after stereotaxic injection of LPS. Our results suggest that Clk1 regulates microglial metabolic reprogramming that is, in turn, involved in the neuroinflammatory processes and PD.

An inherited duplication at the gene p21 Protein-Activated Kinase 7 (PAK7) is a risk factor for psychosis.

Identifying rare, highly penetrant risk mutations may be an important step in dissecting the molecular etiology of schizophrenia. We conducted a gene-based analysis of large (>100 kb), rare copy-number variants (CNVs) in the Wellcome Trust Case Control Consortium 2 (WTCCC2) schizophrenia sample of 1564 cases and 1748 controls all from Ireland, and further extended the analysis to include an additional 5196 UK controls. We found association with duplications at chr20p12.2 (P = 0.007) and evidence of replication in large independent European schizophrenia (P = 0.052) and UK bipolar disorder case-control cohorts (P = 0.047). A combined analysis of Irish/UK subjects including additional psychosis cases (schizophrenia and bipolar disorder) identified 22 carriers in 11 707 cases and 10 carriers in 21 204 controls [meta-analysis Cochran-Mantel-Haenszel P-value = 2 × 10(-4); odds ratio (OR) = 11.3, 95% CI = 3.7, ∞]. Nineteen of the 22 cases and 8 of the 10 controls carried duplications starting at 9.68 Mb with similar breakpoints across samples. By haplotype analysis and sequencing, we identified a tandem ~149 kb duplication overlapping the gene p21 Protein-Activated Kinase 7 (PAK7, also called PAK5) which was in linkage disequilibrium with local haplotypes (P = 2.5 × 10(-21)), indicative of a single ancestral duplication event. We confirmed the breakpoints in 8/8 carriers tested and found co-segregation of the duplication with illness in two additional family members of one of the affected probands. We demonstrate that PAK7 is developmentally co-expressed with another known psychosis risk gene (DISC1) suggesting a potential molecular mechanism involving aberrant synapse development and plasticity.