Effects of single-dose antipurinergic therapy on behavioral and molecular alterations in the valproic acid-induced animal model of autism

Autism spectrum disorder (ASD) is characterized by deficits in communication and social interaction, restricted interests, and stereotyped behavior. Environmental factors, such as prenatal exposure to valproic acid (VPA), may contribute to the increased risk of ASD. Since disturbed functioning of the purinergic system has been associated with the onset of ASD and used as a potential therapeutic target for ASD in both clinical and preclinical studies, we analyzed the effects of suramin, a non-selective purinergic antagonist, on behavioral, molecular and immunological in an animal model of autism induced by prenatal exposure to VPA. Treatment with suramin (20 mg/kg, intraperitoneal) restored sociability in the three-chamber apparatus and decreased anxiety measured by elevated plus maze apparatus, but had no impact on decreased reciprocal social interactions or higher nociceptive threshold in VPA rats. Suramin treatment had no impact on VPA-induced upregulation of P2X4 and P2Y2 in hippocampus, and P2X4 in medial prefrontal cortex, but normalized an increased level of interleukin 6 (IL-6). Our results suggest an important role of purinergic modulation in behavioral, molecular, and immunological aberrations described in VPA model, and suggest that purinergic system might be a potential target for pharmacotherapy in preclinical studies of ASD

Defining Microbial Signatures of Gut Dysbiosis in Models of Anxiety-related Disorders

The gut microbiome is a complex community featuring a bewildering array of microbial species. Over the past couple decades, there has been an explosion of research demonstrating that the gut microbiota plays critical roles in a variety of host functions, including immune modulation, metabolism, brain function, and behavior. Mechanistic approaches such as fecal microbiota transfer from disease models into healthy animals have demonstrated direct effects of gut microbiota on host parameters but sequencing of fecal samples from similar subjects across different cohorts often reveals wide differences in microbial composition. This wide variability is also seen in clinical subjects within specific disease states postulated to be influenced by gut microbiota. Nevertheless, there are likely core features of the gut microbiota that may be modulated across different disease conditions to transmit similar signals to the host. In this dissertation, I focus on potential core features of gut dysbiosis, or alterations in gut microbiota associated with various disease states. In Chapter 2, I will explore variations in gut microbiota observed across a genetic model exhibiting varying behavioral profiles, namely Brattleboro rats. In Chapter 3, I explore the potential mechanistic links between gut microbiota and host behavior, using a treatment that compromises the integrity of the gut barrier (namely, adding food emulsifiers to the diet). Compromising the gut barrier allows increased access of microbial byproducts that affect the CNS. I explored this potential mechanism in Chapter 4 by testing the effects of gut-derived LPS on host behavior, as LPS can compromise gut barrier integrity even further and act on immune cells and vagal gut innervations that communicate with the CNS to affect host behavior. In Chapter 5, I discuss the tools and multivariate investigative approaches employed in the studies discussed in this dissertation, and how multivariate approaches lend required dimensionality to studying a complex gut-brain signaling axis. Gut barrier dysfunction is a common theme observed in various disorders exhibiting altered anxiety behavior and gut dysbiosis of widely-varying microbial compositions. Understanding core functional features of gut dysbiosis will provide an important handle on ameliorating the gut environment in future attempts to treat CNS disorders

CONTINUOUS PREFERENCE DRINKING: A NOVEL PARADIGM TO MODEL FETAL ALCOHOL SPECTRUM DISORDERS

The C57BL/6J inbred mouse strain has been used extensively to study human alcoholism because of its well-established tendency to preferentially consume alcohol-containing solutions over those of pure water. In the current study, this innate preference was exploited to examine the effects of self-administered ethanol by pregnant dams on the outcomes of offspring as a novel rodent model for the Fetal Alcohol Spectrum Disorders (FASD) observed in human populations. Behavioural analyses determined that the acquisition of developmental milestones, spontaneous and nocturnal activity levels, anxiety, learning and memory were significantly altered in offspring of mothers who consumed ethanol during the periods of mouse pup neurodevelopment that correlate with the three trimesters of human pregnancy. Moreover, these behavioural and neuro­ developmental changes were associated with the altered expression of several genes considered important for learning, anxiety, and disorders of central nervous system dysfunction

An investigation into the repetitive pathophysiology and the effect of a noninvasive targeted treatment strategy in an animal model overexpressing the dopamine transporter

Introduction: Treatment of neuropsychiatric disorders may be optimized through targeted strategies that interact with neurobiological processes responsible for symptom generation. The overexpression of the dopamine transporter (DAT) has been linked to a wide range of neuropsychiatric afflictions with a specific involvement in repetitive disorders. However, the direct consequences of DAT overexpression remain unexplored. Transcranial direct current stimulation (tDCS) is a non-invasive technique suggested as a treatment for repetitive disorders. In-depth investigation into the role of DAT overexpression in repetitive pathophysiology and how tDCS potentially regulates these processes are clinically challenging, yet possible by employment of adequate animal models. Objectives: The aim of the present thesis was to investigate the direct consequences of DAT overexpression in relation to the pathophysiology of repetitive behavior and to test the potency of tDCS as a therapeutic approach for repetitive disorders. Methods: Initially, a transgenic rat overexpressing DAT (DAT-tg) was generated and its neurobiological and behavioral properties were assessed (study 1+2). Extensive deep brain stimulation (DBS) was applied to identify, which brain areas were involved in modulating repetitive behavior in the DAT-tg rat. Subsequently, DAT-tg rats received tDCS above the frontal cortex followed by behavioral and neurobiological assessment (study 3). Results: The DAT-tg rat displayed several neurobiological deficits within the corticostriatal circuit related to repetitive pathophysiology, which translated into repetitive behavior and treatment sensitivity as observed Tourette syndrome. Further, DAT-tg rats presented with profound cognitive deficits. The application of frontal anodal tDCS led to a decrease in repetitive symptoms in the DAT-tg rats, which was assigned to a specific modulation within the corticostriatal sensorimotor circuit. Conclusion: This thesis shows that DAT overexpression is implicated in the generation of among others repetitive pathophysiology, thus supporting the need for further investigations into its role in repetitive disorders. It further shows that the DAT-tg rat constitutes an ideal model for this endeavor, as it allows for a direct assessment of the neurobiological implications and how new interventions interact with these processes. This thesis further found, that following application of the appropriate stimulation parameters, tDCS reduces repetitive behavior by modulating the neuronal circuit considered responsible for symptom manifestation in the DAT-tg rats. This sets the stage for investigations into tDCS as targeted treatment for repetitive disorders.Einleitung: Die Behandlung neuropsychiatrischer Erkrankungen kann durch gezielte Therapiestrategien, die in die neurobiologischen Prozesse der Symptomgenerierung eingreifen, optimiert werden. Die Überexpression des Dopamin-Transporters (DAT) wird mit einer Vielzahl neuropsychiatrischer Erkrankungen, die mit repetitiven Störungen einhergehen, in Verbindung gebracht. Dennoch sind die direkten Folgen der Überexpression des DAT bisher unerforscht. Die transkranielle Gleichstromstimulation (tDCS) ist eine nichtinvasive Technik, die zur Behandlung repetitiver Störungen vorgeschlagen wird. Die ausführliche Untersuchung der Rolle der DAT-Überexpression in der repetitiven Pathophysiologie sowie der potentiellen Regulation dieser Prozesse durch die tDCS ist klinisch herausfordernd, jedoch durch die Verwendung geeigneter Tiermodelle möglich. Ziele: Ziel der vorliegenden Studie war es, die direkten Konsequenzen einer DAT-Überexpression in Bezug auf die Pathophysiologie von repetitivem Verhalten zu untersuchen und die Wirksamkeit von tDCS als therapeutischen Ansatz für repetitive Störungen zu testen. Methoden: Zunächst wurde eine transgene Ratte mit überexprimiertem DAT (DAT-tg) generiert und ihre neurobiologischen und Verhaltensmerkmale untersucht (Studie 1+2). Um herauszufinden, welche Gehirnbereiche bei der Modulation des repetitiven Verhaltens in der DAT-tg-Ratte involviert sind, wurde eine umfassende Tiefenhirnstimulation (DBS) angewendet. Anschließend erhielten DAT-tg-Ratten tDCS über dem Frontalkortex und Auswirkungen auf Verhalten und Neurobiologie wurden geprüft (Studie 3). Ergebnisse: Die DAT-tg-Ratte wies in den kortikostriatalen Verbindungen mehrere neurobiologische Defizite auf, wie sie sich im repetitivem Verhalten und der Behandlungsempfindlichkeit bei Tourette- Syndrom beobachten lassen. Des weiteren zeigten DAT-tg-Ratten schwerwiegende kognitive Defizite. Die Anwendung von einer frontalen anodalen tDCS führte zu einer Abnahme der repetitiven Symptomatik bei den DAT-tg-Ratten, die einer spezifischen Modulation innerhalb des kortikostriatalen-sensomotorischen Schaltkreises zugeordnet werden konnte. Schlussfolgerung: Diese Studie zeigt, dass die Überexpression des DAT unter anderem bei der Entstehung von repetitiver Pathophysiologie eine Rolle spielt. Dies unterstreicht die Notwendigkeit weiterer Untersuchungen zur Rolle der DAT Überexpression bei repetitiven Störungen. Es zeigt außerdem, dass die DAT-tg-Ratte ein ideales Modell dafür darstellt, als dass es die direkte Untersuchung neurobiologischer Implikationen und die Wirkung neuartiger Interventionen auf diese Prozesse ermöglicht. Diese Arbeit zeigt, dass tDCS nach Anwendung geeigneter Stimulationsparameter repetitives Verhalten durch Modulation des neuronalen Schaltkreises, welcher für die Symptommanifestation bei den DAT-tg-Ratten verantwortlich gemacht wird, reduziert. Damit sind die Voraussetzungen für tDCS als gezielte Behandlung von repetitiven Erkrankungen geschaffen

Amelioration of prenatal alcohol effects by environmental enrichment in a mouse model of FASD

Maternal alcohol consumption during pregnancy results in a spectrum of behavioural and cognitive deficits collectively known as Fetal Alcohol Spectrum Disorders (FASD). Currently, little is know about if and how the external environment may modulate these deficits. I have used C57BL/6 mice to study this interaction between prenatal alcohol exposure and the postnatal environment. Alcohol exposure during synaptogenesis produces high levels of anxiety-like traits and decreased memory performance. Alcohol-exposed mice (and matched unexposed controls) were put in \u27environmentally-enriched\u27 conditions of voluntary exercise, physical activities and cognitive stimulation to ascertain the effects of a positive postnatal environment. The results show that environmental enrichment ameliorates anxiety-like behaviour and memory deficits of alcohol-exposed mice. However this recovery is incomplete, indicative of the long-lasting, potentially permanent damage of prenatal alcohol exposure on the developing brain. In follow-up studies, I have uncovered gene expression changes in the hippocampus that are associated with behavioural and cognitive amelioration. To accomplish this, I have used mouse hippocampal RNA for microarray and RNA-Seq. My results have identified several key genes and molecular pathways that are associated with synaptic and structural plasticity, neurogenesis, long-term potentiation and angiogenesis. The behavioural and molecular results of this project represent a novel finding in the field of FASD research. The genes and pathways uncovered provide a possible explanation to understand FASD. They are also potential targets when formulating behavioural and pharmacological rehabilitative therapies

Association of limbic system-associated membrane protein (LSAMP) to male completed suicide

<p>Abstract</p> <p>Background</p> <p>Neuroimaging studies have demonstrated volumetric abnormalities in limbic structures of suicide victims. The morphological changes might be caused by some inherited neurodevelopmental defect, such as failure to form proper axonal connections due to genetically determined dysfunction of neurite guidance molecules. Limbic system-associated membrane protein (LSAMP) is a neuronal adhesive molecule, preferentially expressed in developing limbic system neuronal dendrites and somata. Some evidence for the association between LSAMP gene and behavior has come from both animal as well as human studies but further investigation is required. In current study, polymorphic loci in human LSAMP gene were examined in order to reveal any associations between genetic variation in <it>LSAMP </it>and suicidal behaviour.</p> <p>Methods</p> <p>DNA was obtained from 288 male suicide victims and 327 healthy male volunteers. Thirty SNPs from LSAMP gene and adjacent region were selected by Tagger algorithm implemented in Haploview 3.32. Genotyping was performed using the SNPlex™ (Applied Biosystems) platform. Data was analyzed by Genemapper 3.7, Haploview 3.32 and SPSS 13.0.</p> <p>Results</p> <p>Chi square test revealed four allelic variants (rs2918215, rs2918213, rs9874470 and rs4821129) located in the intronic region of the gene to be associated with suicide, major alleles being overrepresented in suicide group. However, the associations did not survive multiple correction test. Defining the haplotype blocks using confidence interval algorithm implemented in Haploview 3.32, we failed to detect any associated haplotypes.</p> <p>Conclusion</p> <p>Despite a considerable amount of investigation on the nature of suicidal behaviour, its aetiology and pathogenesis remain unknown. This study examined the variability in LSAMP gene in relation to completed suicide. Our results indicate that LSAMP might play a role in pathoaetiology of suicidal behaviour but further studies are needed to understand its exact contribution.</p

Resolving the neural circuits of anxiety

Although anxiety disorders represent a major societal problem demanding new therapeutic targets, these efforts have languished in the absence of a mechanistic understanding of this subjective emotional state. While it is impossible to know with certainty the subjective experience of a rodent, rodent models hold promise in dissecting well-conserved limbic circuits. The application of modern approaches in neuroscience has already begun to unmask the neural circuit intricacies underlying anxiety by allowing direct examination of hypotheses drawn from existing psychological concepts. This information points toward an updated conceptual model for what neural circuit perturbations could give rise to pathological anxiety and thereby provides a roadmap for future therapeutic development.National Institute of Diabetes and Digestive and Kidney Diseases (U.S.) (NIH Director’s New Innovator Award DP2-DK-102256-01)National Institute of Mental Health (U.S.) (NIH) R01-MH102441-01)JPB Foundatio

Celebration Schedule 2015 (Friday)

Full presentation schedule for Celebration, Friday, May 1, 201

Transgenic mice expressing constitutive active MAPKAPK5 display gender-dependent differences in exploration and activity

<p>Abstract</p> <p>Background</p> <p>The mitogen-activated protein kinases, MAPKs for short, constitute cascades of signalling pathways involved in the regulation of several cellular processes that include cell proliferation, differentiation and motility. They also intervene in neurological processes like fear conditioning and memory. Since little remains known about the MAPK-Activated Protein Kinase, MAPKAPK5, we constructed the first MAPKAPK knockin mouse model, using a constitutive active variant of MAPKAPK5 and analyzed the resulting mice for changes in anxiety-related behaviour.</p> <p>Methods</p> <p>We performed primary SHIRPA observations during background breeding into the C57BL/6 background and assessed the behaviour of the background-bred animals on the elevated plus maze and in the light-dark test. Our results were analyzed using Chi-square tests and homo- and heteroscedatic T-tests.</p> <p>Results</p> <p>Female transgenic mice displayed increased amounts of head dips and open arm time on the maze, compared to littermate controls. In addition, they also explored further into the open arm on the elevated plus maze and were less active in the closed arm compared to littermate controls. Male transgenic mice displayed no differences in anxiety, but their locomotor activity increased compared to non-transgenic littermates.</p> <p>Conclusion</p> <p>Our results revealed anxiety-related traits and locomotor differences between transgenic mice expressing constitutive active MAPKAPK5 and control littermates.</p

Dorsal Periaqueductal gray ensembles represent approach and avoidance states

Animals must balance needs to approach threats for risk assessment and to avoid danger. The dorsal periaqueductal gray (dPAG) controls defensive behaviors, but it is unknown how it represents states associated with threat approach and avoidance. We identified a dPAG threatavoidance ensemble in mice that showed higher activity farther from threats such as the open arms of the elevated plus maze and a predator. These cells were also more active during threat avoidance behaviors such as escape and freezing, even though these behaviors have antagonistic motor output. Conversely, the threat approach ensemble was more active during risk assessment behaviors and near threats. Furthermore, unsupervised methods showed that avoidance/approach states were encoded with shared activity patterns across threats. Lastly, the relative number of cells in each ensemble predicted threat avoidance across mice. Thus, dPAG ensembles dynamically encode threat approach and avoidance states, providing a flexible mechanism to balance risk assessment and danger avoidance