Dopaminergic control of ADAMTS2 expression through cAMP/CREB and ERK: molecular effects of antipsychotics.

A better understanding of the molecular mechanisms that participate in the development and clinical manifestations of schizophrenia can lead to improve our ability to diagnose and treat this disease. Previous data strongly associated the levels of deregulated ADAMTS2 expression in peripheral blood mononuclear cells (PBMCs) from patients at first episode of psychosis (up) as well as in clinical responders to treatment with antipsychotic drugs (down). In this current work, we performed an independent validation of such data and studied the mechanisms implicated in the control of ADAMTS2 gene expression. Using a new cohort of drug-naïve schizophrenia patients with clinical follow-up, we confirmed that the expression of ADAMTS2 was highly upregulated in PBMCs at the onset (drug-naïve patients) and downregulated, in clinical responders, after treatment with antipsychotics. Mechanistically, ADAMTS2 expression was activated by dopaminergic signalling (D1-class receptors) and downstream by cAMP/CREB and mitogen-activated protein kinase (MAPK)/ERK signalling. Incubation with antipsychotic drugs and selective PKA and MEK inhibitors abrogated D1-mediated activation of ADAMTS2 in neuronal-like cells. Thus, D1 receptors signalling towards CREB activation might participate in the onset and clinical responses to therapy in schizophrenia patients, by controlling ADAMTS2 expression and activity. The unbiased investigation of molecular mechanisms triggered by antipsychotic drugs may provide a new landscape of novel targets potentially associated with clinical efficacy.

Selective up-regulation of cannabinoid CB1 receptor coupling to Go-proteins in suicide victims with mood disorders.

Brain endocannabinoid system is proposed to play a role in the pathogenesis of affective disorders. In the present study, we analyzed the functionality of the cannabinoid receptor type 1 (CB1 receptor) at different transduction levels in prefrontal cortex (PFC) of depressed suicide victims. We examined stimulation of [35S]GTPγS binding, activation of Gα protein subunits and inhibition of adenylyl cyclase by the cannabinoid agonist WIN55,212-2, as well as [3H]CP55,940 binding, in PFC homogenates from suicide victims with major depression (MD) and matched control subjects. CB1 receptor-stimulated [35S]GTPγS binding was significantly greater in the PFC of MD compared with matched controls (23%, p < 0.05). This increase was most evident in the PFC from MD subgroup with negative blood test for antidepressants (AD) at the time of death (AD-free) (38%, p < 0.05), being absent when comparing the AD-treated MD cases with their controls. The density of CB1 receptors and their coupling to adenylyl cyclase were similar between MD and control cases, regardless of the existence of AD intake. Analysis of [35S]GTPγS-labelled Gα subunits allowed for the detection of upregulated CB1 receptor coupling to Gαo, but not to Gαi1, Gαi2, Gαi3, Gαz subunits, in the PFC from AD-free MD suicides. These results suggest that increased CB1 receptor functionality at the Gαi/o protein level in the PFC of MD subjects is due to enhanced coupling to Gαo proteins and might be modulated by AD intake. These data provide new insights into the role of endocannabinoid neurotransmission in the pathobiology of MD and suggest its regulation by ADs.

Effects of aripiprazole, quetiapine and ziprasidone on plasma prolactin levels in individuals with first episode nonaffective psychosis: Analysis of a randomized open-label 1year study.

RATIONALE: Hyperprolactinemia is considered a troubling adverse effect of antipsychotics. Direct comparisons among second generation antipsychotics are scant in clinical practice. We hypothesize prolactin-sparing second-generation antipsychotics may have differential effects on prolactin levels and that they may be influenced by sex. OBJECTIVES: To explore the differential effect of three widely used prolactin-sparing antipsychotics, aripiprazole, quetiapine and ziprasidone, on prolactin plasma levels in first episode non-affective psychosis during a 1year of treatment. METHOD: From October 2005 to January 2011 a prospective, randomized, open-label study was undertaken. 141 patients who were randomly allocated to aripiprazole (N=56), quetiapine (N=36) or ziprasidone (N=49) were analyzed. The main outcome was differences in prolactin plasma levels over 1year follow-up among the three antipsychotics. Prolactin levels had a skewed distribution and therefore they were log-transformed before statistical analyses. RESULTS: Male patients on aripiprazole had a lower risk of suffering an increase on prolactin plasma levels (N=71; F=12.645; p<0.001). There was a gender effect with smaller changes in mean prolactin values only in males. Aripiprazole had a reduced risk of hyperprolactinemia (aripiprazole 19.6%) compared to quetiapine (44.4%) and ziprasidone (32.7%) (p=0.038); and quite similar findings were found when investigating males (p=0.040). No significant differences were found in females. The percentages of mild prolactin excess were: 14.3% on aripiprazole, 36.1% on quetiapine and 18.4% on ziprasidone (χ2=6.611 p=0.037). CONCLUSIONS: Our findings provide additional evidence of differential effects of three sparing-prolactin antipsychotics on prolactin release and may help clinicians to decide among therapeutic options.

The Addiction-Related Protein ANKK1 is Differentially Expressed During the Cell Cycle in Neural Precursors.

TaqIA is a polymorphism associated with addictions and dopamine-related traits. It is located in the ankyrin repeat and kinase domain containing 1 gene (ANKK1) nearby the gene for the dopamine D2 receptor (D2R). Since ANKK1 function is unknown, TaqIA-associated traits have been explained only by differences in D2R. Here we report ANKK1 studies in mouse and human brain using quantitative real-time PCR, Western blot, immunohistochemistry, and flow cytometry. ANKK1 mRNA and protein isoforms vary along neurodevelopment in the human and mouse brain. In mouse adult brain ANKK1 is located in astrocytes, nuclei of postmitotic neurons and neural precursors from neurogenic niches. In both embryos and adults, nuclei of neural precursors show significant variation of ANKK1 intensity. We demonstrate a correlation between ANKK1 and the cell cycle. Cell synchronization experiments showed a significant increment of ANKK1-kinase in mitotic cells while ANKK1-kinase overexpression affects G1 and M phase that were found to be modulated by ANKK1 alleles and apomorphine treatment. Furthermore, during embryonic neurogenesis ANKK1 was expressed in slow-dividing neuroblasts and rapidly dividing precursors which are mitotic cells. These results suggest a role of ANKK1 during the cell cycle in neural precursors thus providing biological support to brain structure involvement in the TaqIA-associated phenotypes.

Behavioral, neurochemical and molecular changes after acute deep brain stimulation of the infralimbic prefrontal cortex.

Deep brain stimulation (DBS) is a treatment that has shown some efficacy in treatment-resistant depression. In particular, DBS of the subcallosal cingulate gyrus (Brodmann's area 25, Cg25) has been successfully applied to treat refractory depression. In the rat, we have demonstrated that DBS applied to infralimbic (IL) cortex elevates the levels of glutamate and monoamines in the prefrontal cortex, and requires the stimulation of cortical α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) glutamate receptors for its antidepressant-like effects. However, the molecular targets of IL DBS are not fully known. To gain insight into these pathways, we have investigated whether IL DBS is able to reverse the behavioral, biochemical and molecular changes exhibited by the olfactory bulbectomized (OBX) rat. Our results revealed that 1 h IL DBS diminished hyperlocomotion, hyperemotionality and anhedonia, and increased social interaction shown by the OBX rats. Further, IL DBS increased prefrontal efflux of glutamate and serotonin in both sham-operated and OBX rats. With regard to molecular targets, IL DBS increases the synthesis of brain-derived neurotrophic factor (BDNF) and the GluA1 AMPA receptor subunit, and stimulates the Akt/mammalian target of rapamycin (mTOR) as well as the AMPA receptor/c-AMP response element binding (CREB) pathways. Temsirolimus, a known in vivo mTOR blocker, suppressed the antidepressant-like effect of IL DBS in naïve rats in the forced swim test, thus demonstrating for the first time that mTOR signaling is required for the antidepressant-like effects of IL DBS, which is in line with the antidepressant response of other rapid-acting antidepressant drugs.

Clinical outcome after antipsychotic treatment discontinuation in functionally recovered first-episode nonaffective psychosis individuals: a 3-year naturalistic follow-up study.

OBJECTIVE: The timing of antipsychotic discontinuation in patients who have fully recovered from their initial episode of psychosis is still open to discussion. We aimed to evaluate the risk of symptom recurrence during the 3 years after antipsychotic discontinuation in a sample of functionally recovered first-episode nonaffective psychosis (FEP) patients (DSM-IV criteria) with schizophrenia spectrum disorder. METHOD: Participants in this open-label, nonrandomized, prospective study were drawn from an ongoing longitudinal intervention program of FEP from a university hospital setting in Spain. From July 2004 to February 2011, functionally recovered FEP individuals were eligible if they met the inclusion criteria of (1) a minimum of 18 months on antipsychotic treatment, (2) clinical remission for at least 12 months, (3) functional recovery for at least 6 months, and (4) stabilization at the lowest effective doses for at least 3 months. Forty-six individuals who were willing to discontinue medication were included in the discontinuation group (target group). Twenty-two individuals opted to stay on the prescribed antipsychotic medication and therefore were included in the maintenance group (control group). Primary outcome measures were relapse rate at 18 and 36 months and time to relapse. RESULTS: The rates of relapse over the 3-year period were 67.4% (31 of 46) in the discontinuation group and 31.8% (7 of 22) in the maintenance group. The mean time to relapse was 209 (median = 122) days and 608 (median = 607) days, respectively (log rank = 10.106, P = .001). The resumption of antipsychotic medication after the relapse occurred was associated with clinical stability and lack of further relapses. When the overall group of relapsed individuals from the 2 conditions (N = 38) was compared to those who remained asymptomatic after 3 years (N = 30), there were significant differences (P < .05) in total scores on the Scale for the Assessment of Negative Symptoms, the Clinical Global Impressions scale, and the Disability Assessment Schedule. CONCLUSIONS: Antipsychotic treatment discontinuation in individuals who had accomplished a functional recovery after a single psychotic episode was associated with a high risk of symptom recurrence. Relapsed individuals had a greater severity of symptoms and lower functional status after 3 years. TRIAL REGISTRATION: ClinicalTrials.gov identifier: NCT02220504.

Individualized strategies to target specific mechanisms of disease in malignant melanoma patients displaying unique mutational signatures.

Targeted treatment of advanced melanoma could benefit from the precise molecular characterization of melanoma samples. Using a melanoma-specific selection of 217 genes, we performed targeted deep sequencing of a series of biopsies, from advanced melanoma cases, with a Breslow index of ≥ 4 mm, and/or with a loco-regional infiltration in lymph nodes or presenting distant metastasis, as well of a collection of human cell lines. This approach detected 3-4 mutations per case, constituting unique mutational signatures associated with specific inhibitor sensitivity. Functionally, case-specific combinations of inhibitors that simultaneously targeted MAPK-dependent and MAPK-independent mechanisms were most effective at inhibiting melanoma growth, against each specific mutational background. These observations were challenged by characterizing a freshly resected biopsy from a metastatic lesion located in the skin and soft tissue and by testing its associated therapy ex vivo and in vivo using melanocytes and patient-derived xenografted mice, respectively. The results show that upon mutational characterization of advanced melanoma patients, specific mutational profiles can be used for selecting drugs that simultaneously target several deregulated genes/pathways involved in tumor generation or progression.

Small Molecule Inhibition of ERK Dimerization Prevents Tumorigenesis by RAS-ERK Pathway Oncogenes.

Nearly 50% of human malignancies exhibit unregulated RAS-ERK signaling; inhibiting it is a valid strategy for antineoplastic intervention. Upon activation, ERK dimerize, which is essential for ERK extranuclear, but not for nuclear, signaling. Here, we describe a small molecule inhibitor for ERK dimerization that, without affecting ERK phosphorylation, forestalls tumorigenesis driven by RAS-ERK pathway oncogenes. This compound is unaffected by resistance mechanisms that hamper classical RAS-ERK pathway inhibitors. Thus, ERK dimerization inhibitors provide the proof of principle for two understudied concepts in cancer therapy: (1) the blockade of sub-localization-specific sub-signals, rather than total signals, as a means of impeding oncogenic RAS-ERK signaling and (2) targeting regulatory protein-protein interactions, rather than catalytic activities, as an approach for producing effective antitumor agents.

Desarrollo profesional en investigación traslacional en neurociencias y salud mental: educación y formación dentro del Centro de Investigación Biomédica en Red en Salud Mental / Building up careers in translational neuroscience and mental health research: Education and training in the Centre for Biomedical Research in Mental Health

Aumenta el número de redes de investigación colaborativas en salud mental y con ello la importancia de los programas de formación como parte esencial de la especialización de sus miembros. A continuación revisamos de un modo crítico la implementación específica de un programa de formación en investigación traslacional en salud mental y neurociencias en el Centro de Investigación Biomédica en Red en Salud Mental, con el fin de informar sobre la integración estratégica de la investigación básica dentro de la práctica clínica y lograr un impacto positivo en los sistemas de salud mental y la sociedad. Se examinan las actividades de formación y los programas específicos desarrollados por la red de investigación, así como los desafíos de su implementación. El Centro de Investigación Biomédica en Red en Salud Mental ha centrado su formación a través de diferentes actividades que han dado lugar al desarrollo de un máster interuniversitario y a un programa de posgrado en Investigación en Salud Mental, certificado por la Agencia Nacional de Evaluación de la Calidad y Acreditación. La consolidación de los programas de formación dentro del Centro de Investigación Biomédica en Red en Salud Mental ha supuesto un avance considerable para la formación de los investigadores, a fin de satisfacer las necesidades actuales de competencia en materia de investigación. El máster constituye una oportunidad única para el desarrollo de las habilidades necesarias en investigación en neurociencia y salud mental dentro del marco oficial de los programas universitarios en España (AU)

The number of large collaborative research networks in mental health is increasing. Training programs are an essential part of them. We critically review the specific implementation of a research training program in a translational Centre for Biomedical Research in Mental Health in order to inform the strategic integration of basic research into clinical practice to have a positive impact in the mental health system and society. Description of training activities, specific educational programs developed by the research network, and challenges on its implementation are examined. The Centre for Biomedical Research in Mental Health has focused on training through different activities which have led to the development of an interuniversity master's degree postgraduate program in mental health research, certified by the National Spanish Agency for Quality Evaluation and Accreditation. Consolidation of training programs within the Centre for Biomedical Research in Mental Health has considerably advanced the training of researchers to meet competency standards on research. The master's degree constitutes a unique opportunity to accomplish neuroscience and mental health research career-building within the official framework of university programs in Spain (AU)

Building up careers in translational neuroscience and mental health research: Education and training in the Centre for Biomedical Research in Mental Health.

The number of large collaborative research networks in mental health is increasing. Training programs are an essential part of them. We critically review the specific implementation of a research training program in a translational Centre for Biomedical Research in Mental Health in order to inform the strategic integration of basic research into clinical practice to have a positive impact in the mental health system and society. Description of training activities, specific educational programs developed by the research network, and challenges on its implementation are examined. The Centre for Biomedical Research in Mental Health has focused on training through different activities which have led to the development of an interuniversity master's degree postgraduate program in mental health research, certified by the National Spanish Agency for Quality Evaluation and Accreditation. Consolidation of training programs within the Centre for Biomedical Research in Mental Health has considerably advanced the training of researchers to meet competency standards on research. The master's degree constitutes a unique opportunity to accomplish neuroscience and mental health research career-building within the official framework of university programs in Spain.

The endocannabinoid system is altered in the post-mortem prefrontal cortex of alcoholic subjects.

There is strong biochemical, pharmacological and genetic evidence for the involvement of the endocannabinoid system (ECS) in alcohol dependence. However, the majority of studies have been performed in animal models. The aim of the present study was to assess the state of the CB1 receptor, the enzymes fatty acid amide hydrolase (FAAH) and monoacylglycerol lipase (MAGL), and the extracellular signal-regulated kinase (ERK) and cyclic-AMP response element-binding protein (CREB) in the post-mortem prefrontal cortex of alcoholic subjects. Experiments were performed in samples from 44 subjects classified in four experimental groups: (1) non-suicidal alcoholic subjects (n = 11); (2) suicidal alcoholic subjects (n = 11); (3) non-alcoholic suicide victims (n = 11); and (4) control subjects (n = 11). We did not observe statistically significant differences in CB1 mRNA relative expression among the four experimental groups. Conversely, our results showed an increase in CB1 receptor protein expression in the prefrontal cortex of the suicidal alcoholic group (127.2 ± 7.3%), with no changes in functionality with regard to either G protein activation or the inhibition of adenylyl cyclase. In parallel, alcoholic subjects presented lower levels of MAGL activity, regardless of the cause of death. A significant decrease in the active form of ERK and CREB levels was also observed in both alcoholic groups. Taken together, our data are consistent with a role for the ECS in the neurobiological mechanisms underlying alcoholism. Moreover, the alterations reported here should be of great interest for the therapeutic treatment of this chronic psychiatric disease.

Increased SP4 and SP1 transcription factor expression in the postmortem hippocampus of chronic schizophrenia.

Altered levels of transcription factor specificity protein 4 (SP4) and 1 (SP1) in the cerebellum, prefrontal cortex and/or lymphocytes have been reported in severe psychiatric disorders, including early psychosis, bipolar disorder, and chronic schizophrenia subjects who have undergone long-term antipsychotic treatments. SP4 transgenic mice show altered hippocampal-dependent psychotic-like behaviours and altered development of hippocampal dentate gyrus. Moreover, NMDAR activity regulates SP4 function. The aim of this study was to investigate SP4 and SP1 expression levels in the hippocampus in schizophrenia, and the possible effect of antipsychotics and NMDAR blockade on SP protein levels in rodent hippocampus. We analysed SP4 and SP1 expression levels in the postmortem hippocampus of chronic schizophrenia (n = 14) and control (n = 11) subjects by immunoblot and quantitative RT-PCR. We tested the effect of NMDAR blockade on SP factors in the hippocampus of mouse treated with an acute dose of MK801. We also investigated the effect of subacute treatments with haloperidol and clozapine on SP protein levels in the rat hippocampus. We report that SP4 protein and both SP4 and SP1 mRNA expression levels are significantly increased in the hippocampus in chronic schizophrenia. Likewise, acute treatment with MK801 increased both SP4 and SP1 protein levels in mouse hippocampus. In contrast, subacute treatment with haloperidol and clozapine did not significantly alter SP protein levels in rat hippocampus. These results suggest that SP4 and SP1 upregulation may be part of the mechanisms deregulated downstream of glutamate signalling pathways in schizophrenia and might be contributing to the hippocampal-dependent cognitive deficits of the disorder.

TGF-ß and opioid receptor signaling crosstalk results in improvement of endogenous and exogenous opioid analgesia under pathological pain conditions.

Transforming growth factor-ß1 (TGF-ß1) protects against neuroinflammatory events underlying neuropathic pain. TGF-ß signaling enhancement is a phenotypic characteristic of mice lacking the TGF-ß pseudoreceptor BAMBI (BMP and activin membrane-bound inhibitor), which leads to an increased synaptic release of opioid peptides and to a naloxone-reversible hypoalgesic/antiallodynic phenotype. Herein, we investigated the following: (1) the effects of BAMBI deficiency on opioid receptor expression, functional efficacy, and analgesic responses to endogenous and exogenous opioids; and (2) the involvement of the opioid system in the antiallodynic effect of TGF-ß1. BAMBI-KO mice were subjected to neuropathic pain by sciatic nerve crash injury (SNI). Gene (PCR) and protein (Western blot) expressions of µ- and δ-opioid receptors were determined in the spinal cord. The inhibitory effects of agonists on the adenylyl cyclase pathway were investigated. Two weeks after SNI, wild-type mice developed mechanical allodynia and the functionality of µ-opioid receptors was reduced. By this time, BAMBI-KO mice were protected against allodynia and exhibited increased expression and function of opioid receptors. Four weeks after SNI, when mice of both genotypes had developed neuropathic pain, the analgesic responses induced by morphine and RB101 (an inhibitor of enkephalin-degrading enzymes, which increases the synaptic levels of enkephalins) were enhanced in BAMBI-KO mice. Similar results were obtained in the formalin-induced chemical-inflammatory pain model. Subcutaneous TGF-ß1 infusion prevented pain development after SNI. The antiallodynic effect of TGF-ß1 was naloxone-sensitive. In conclusion, modulation of the endogenous opioid system by TGF-ß signaling improves the analgesic effectiveness of exogenous and endogenous opioids under pathological pain conditions.

Treatment of first-episode non-affective psychosis: a randomized comparison of aripiprazole, quetiapine and ziprasidone over 1 year.

RATIONALE: Discontinuation of antipsychotic treatment at early phases increases the risk of poor adherence to maintenance drug therapy. Differences among antipsychotics in terms of effectiveness may determine a good adherence to treatment. OBJECTIVES: The aim of this study is to compare the clinical effectiveness of aripiprazole, ziprasidone and quetiapine in the treatment of first-episode schizophrenia spectrum disorders at 1 year. METHOD: From October 2005 to January 2011 a prospective, randomized, open-label study was undertaken. Two hundred two first-episode drug-naïve patients were randomly assigned to aripiprazole (N = 78), ziprasidone (N = 62), or quetiapine (N = 62) and followed up for 1 year. The primary effectiveness measure was all-cause of treatment discontinuation. In addition, an analysis based on intention-to-treat principle was conducted in the analysis for clinical efficacy. RESULTS: The overall dropout rate at 1 year was 13.37 %. The treatment discontinuation rate differed significantly between treatment groups (aripiprazole = 43.6 %, ziprasidone = 66.1 % and quetiapine = 82.3 %) (χ 2 = 22.545; p < 0.001). Insufficient efficacy in the group of quetiapine is the most important reason for differences in discontinuation rates between agents (χ 2 = 19.436; p < 0.001). The mean time to all-cause discontinuation was significantly different between groups (LogRank = 30.732 p < 0.001). The profile of extrapyramidal symptoms varies between treatments. Patients on ziprasidone were more likely to be prescribed antidepressants. CONCLUSIONS: First episode patients treated with quetiapine have a higher risk of treatment discontinuation at midterm due to insufficient efficacy. Establishing differences between SGAs may help clinicians on prescribing decision for treatment of individuals presenting with first-episode non-affective psychosis.

Signaling pathways involved in antidepressant-induced cell proliferation and synaptic plasticity.

In the last years it has been proposed that the antidepressant action is mediated not only by changes in monoamine levels but also in association with modifications involving cell proliferation and plasticity in some brain limbic areas as hippocampus, and also frontal cortex and amygdala. This leads to the merging of the classic "monoaminergic hypothesis of depression", with the newer "neurotrophic hypothesis of depression". Here we review two important signaling pathways: the Wnt/ß-catenin pathway -implicated in cellular proliferation and synaptic plasticity- that is downregulated in major depression and upregulated after antidepressant treatment; and the mTOR pathway -controling synaptic plasticity- recently related to present disrupted functioning in major depression, and as the target of some drugs with fast-acting potential antidepressant action. These pieces of evidences are confirmed in a variety of animal models of depression and are predictive of antidepressant actions. We also review the role of another two important neurotrophic factors: brain derived neurotrophic factor (BDNF) and vascular endothelial growth factor (VEGF) that mediate the antidepressant effects. All of the above intracellular pathways interact by a crosstalk mediated by Akt, a key regulator molecule that may underlie the fine tuning between proliferative and neuroplasticity changes induced by antidepressant drugs.

Serotonin 5-HT4 receptors: A new strategy for developing fast acting antidepressants?

The regulation of the activity of brain monoaminergic systems has been the focus of attention of many studies since the first antidepressant drug emerged 50 years ago. The search for novel antidepressants is deeply linked to the search for fast-acting strategies, taking into account that 2-4 weeks of treatment with classical antidepressant are required before clinical remission of the symptoms becomes evident. In the recent years several hypotheses have been proposed on the basis of the existence of alterations in brain synaptic plasticity in major depression. Recent evidences support a role for 5-HT4 receptors in the pathogenesis of depression as well as in the mechanism of action of antidepressant drugs. In fact, chronic treatment with antidepressant drugs appears to modulate, at different levels, the signaling pathway associated to 5-HT4 receptors, as well as their levels of expression in the brain. Moreover, several experimental studies have identified this receptor subtype as a promising new target for fast-acting antidepressant strategy: the administration of partial agonists of this receptor induces a number of responses similar to those observed after chronic treatment with classical antidepressants, but with a rapid onset of action. They include efficacy in behavioral models of depression, rapid desensitization of 5-HT1A autoreceptors, and modifications in the expression of several molecular markers of brain neuroplasticity. Although much work remains to be done in order to clarify the real therapeutic potential of these drugs, the evidences reviewed below support the hypothesis that 5-HT4 receptor partial agonists could behave as rapid and effective antidepressants.

Absence of core autophagy gene expression in an ex vivo central nervous system model infected with Listeria monocytogenes

Estudios recientes han evidenciado que la autofagia puede actuar como un mecanismo inmune protector frente a la infección con Listeria monocytogenes. L. monocytogenes es una bacteria grampositiva, intracelular facultativa, que causa enfermedades invasivas en humanos y animales, especialmente en el sistema nervioso central (SNC). La listeriosis humana en el SNC puede manifestarse de diferentes maneras, incluyendo meningitis y abscesos cerebrales. La línea principal de defensa frente a las infecciones bacterianas es proporcionada por la microglía, fagocitos residentes del parénquima del SNC. Las células de microglía son conocidas, también, por eliminar las células dañadas o muertas tras un daño cerebral, y por lo tanto desempeñan un papel clave en las enfermedades infecciosas y neurodegenerativas. Se sabe poco sobre el papel de la autofagia en las interacciones entre el hospedador y el patógeno, debido a que la mayoría de los estudios in vitro han usado macrófagos o células epiteliales. En el presente trabajo hemos utilizado matrices de PCR en tiempo real para analizar la expresión de genes de autofagia en un modelo organotípico de cerebro de rata infectado con L. monocytogenes. Hemos observado que, en general, la expresión de genes centrales de la autofagia no está modulada por la infección, a pesar de la presencia de una intensa actividad fagocítica de la microglía en la superficie del tejido cerebral, observada mediante microscopia electrónica de barrido. Concluimos que, en nuestro modelo, la autofagia podría desempeñar un papel clave en la homeostasis del tejido dañado en lugar de tener un papel inmune relevante(AU)

Recent studies have suggested that autophagy can act as a protective immune mechanism against Listeria monocytogenes infection. L. monocytogenes is a Gram-positive, facultative intracellular bacterium that causes invasive diseases in humans and animals, particularly in the central nervous system (CNS). Human listeriosis of the CNS can manifest in many ways, including meningitis and brain abscesses. The initial line of defence against bacterial colonisation is provided by microglia, resident phagocytes of the CNS parenchyma. Microglial cells are also well known for clearing dead and dying neural cells after injury, and therefore play a key role in infectious diseases and neurodegeneration. Little is known about the role of the autophagy pathway in host–pathogen interactions in the brain as most in vitro studies have used macrophages or epithelial cells to study this interaction. In the present work, a quantitative real time-PCR array analysis was performed to assess autophagy-related gene expression in a brain rat ex vivo organotypic nervous system model during L. monocytogenes infection. We found that, in brief, core autophagy gene expression is not modulated by the infection, despite the presence of intense microglial phagocytic activity on the brain tissue surface that can be seen by scanning electron microscopy. We conclude that, in our model, autophagy could play a role in homeostasis in the damaged brain tissue instead of an immune-relevant pathway (AU)

Neural plasticity and proliferation in the generation of antidepressant effects: hippocampal implication.

It is widely accepted that changes underlying depression and antidepressant-like effects involve not only alterations in the levels of neurotransmitters as monoamines and their receptors in the brain, but also structural and functional changes far beyond. During the last two decades, emerging theories are providing new explanations about the neurobiology of depression and the mechanism of action of antidepressant strategies based on cellular changes at the CNS level. The neurotrophic/plasticity hypothesis of depression, proposed more than a decade ago, is now supported by multiple basic and clinical studies focused on the role of intracellular-signalling cascades that govern neural proliferation and plasticity. Herein, we review the state-of-the-art of the changes in these signalling pathways which appear to underlie both depressive disorders and antidepressant actions. We will especially focus on the hippocampal cellularity and plasticity modulation by serotonin, trophic factors as brain-derived neurotrophic factor (BDNF), and vascular endothelial growth factor (VEGF) through intracellular signalling pathways-cAMP, Wnt/ ß -catenin, and mTOR. Connecting the classic monoaminergic hypothesis with proliferation/neuroplasticity-related evidence is an appealing and comprehensive attempt for improving our knowledge about the neurobiological events leading to depression and associated to antidepressant therapies.

Aripiprazole, Ziprasidone and Quetiapine in the treatment of first-episode nonaffective psychosis: a 12-week randomized, flexible-dose, open-label trial.

BACKGROUND: Differences among antipsychotics in terms of effectiveness have turned out to be a topic of increasing research interest, although comparisons between the different second generation antipsychotics (SGAs) are scarce. We aimed to compare the clinical effectiveness in the short-term of Aripiprazole, Ziprasidone and Quetiapine in the treatment of first-episode schizophrenia-spectrum disorders. METHOD: From October 2005 to January 2011, a prospective, randomized, open-label study was undertaken. 202 first-episode drug-naïve patients were randomly assigned to Aripiprazole (N = 78), Ziprasidone (N = 62), or Quetiapine (N = 62) and followed-up for 3 months. The primary effectiveness measure was all-cause of treatment discontinuation. In addition, an analysis based on intention-to-treat populations was conducted in the analysis for clinical efficacy. RESULTS: The overall dropout rate at 3 months was small (13.86%). The treatment discontinuation rate differed significantly between treatment groups (Aripiprazole = 23.1%, Ziprasidone = 37.1% and Quetiapine = 61.3%) (χ(2) = 21.334; p < 0.001). Insufficient efficacy in the group of Quetiapine is the main reason for discontinuation rate differences (χ(2) = 20.223; p < 0.001). The mean time to all-cause discontinuation was significantly different between groups (LogRank = 23.467 p < 0.001). Aripiprazole and Quetiapine were associated with a greater depressive symptoms improvement (p = 0.043). The profile of side-effects varies between treatments. Patients on Quetiapine were less likely to be prescribed hypnotics. CONCLUSIONS: Patients treated with Quetiapine had a higher risk of treatment discontinuation in the short-term after a first episode due to insufficient efficacy. Establishing differences between SGAs may help clinicians in prescribing decisions for the treatment of individuals presenting with first-episode schizophrenia.