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09:00-11:00 Session 6: Symposium 1

Genetics & neurobiology of disordered eating


Elucidation of Secretin in thirst regulation within subfornical organ neurons in the brain

ABSTRACT. Precise regulation of plasma osmolality is critical in all terrestrial animals to maintain a constant internal environment and prevent continual water loss. Dysregulation of water homeostasis can result in life-threatening disorders including congestive heart failure and cerebral trauma. Secretin (SCT), a classical gastrointestinal hormone, has been newly described as an osmoregulatory neurohormone that modulates hyperosmolality-induced water drinking behaviour and vasopressin (Vp) release in the hypothalamus. Yet, its molecular mechanism and neural circuitry within the osmoregulatory brain centres is still ripe for exploration. When plasma osmolality changes, subfornical organ (SFO) acts as the first station to detect the changes and transduce them into neuronal signals to other brain regions for corresponding responses. Previous data have shown a wide expression of SCT and its receptor (SCTR) in SFO, and dehydration would increase this expression in SFO. Therefore, we hypothesized that SCT may serve as a neurotransmitter in SFO and modulate water drinking behaviour and Vp release. In this study, we established two specific conditional knockout mice models (SCTSFO-/- and SCTRSFO-/-) to elucidate the role of SCT/SCTR in SFO and investigate its downstream pathway regarding dehydration-induced water intake. We found a marked reduction of water intake in both SCTSFO-/- and SCTRSFO-/- mice (72% drop, p=0.0015; 65% drop, p=0.0387 v.s. sham control) under water-depleted condition. Dehydration-induced cFos expression in SFO was abolished if SCT and SCTR were locally deleted. Thus, current data adds a new piece of information into SCT-mediated osmoregulatory mechanism and may also provide new insights into curing water balance disorders.

Sarah O.K. Mak1, Billy K.C. Chow1 1School of Biological Sciences, The University of Hong Kong, Hong Kong SAR, China

Funding support: This work is supported by Hong Kong Government Research Grant Council Grants GRF HKU17127718 (to B.K.C.C.). The authors declare no conflicts of interest.

Forward genetic and gene validation studies of binge-like eating in mice: Sex-sensitive genetic loci, including male-specific linkage with the Tas2r locus

ABSTRACT. Eating disorders, including binge eating disorder, bulimia nervosa, and anorexia nervosa are highly lethal, heritable disorders with psychiatric and metabolic components. However, the genetic basis of binge eating is completely unknown. Discovery-based genetic and genomic studies in rodents complement human GWAS and can inform genes, networks, and biological pathways underlying maladaptive feeding. We mapped and validated Cyfip2 as a causal genetic factor underlying binge-like eating (BE) in a Reduced Complexity Cross (RCC) and extended these findings to Cyfip1 where we found complex, sex-specific, parent-of-origin selective effects of Cyfip1 haploinsufficiency on BE. In extending our BE model toward additional genetic crosses, we report robust inbred strain differences in BE and conditioned reward between C57BL/6J and DBA/2J strains in our intermittent, limited access, conditioned place preference paradigm. Candidate locus analysis in F2 mice (N=133) identified a male-specific association of the Tas2r locus on chromosome 6 (133 Mb) with escalated BE. Subsequent genome-wide analysis of BE in the same mice with 3K markers confirmed male-specific genome-wide significant linkage on chromosome 6 (LOD=6.0) and resolved the peak location to 53 cM [113 Mb; 48-59 cM). We also identified a sex-averaged QTL on chromosome 5 [peak=28 cM (53 Mb); LOD=5.2; 21-58 cM), and a female-sensitive QTL on chromosome 8 [LOD=4.1; peak=53 cM (109 Mb); 52-59 cM]. The emerging sex-sensitive genetic architecture of BE in mice has important implications for human GWAS and future therapeutics. Future studies will determine the role of sex hormones and sex chromosomes in the genetic architecture of BE.

Camron D. Bryant1, Richard K. Babbs1, Emily Yao1, Melanie M. Chen1, Julia C. Kelliher1, Julia L. Scotellaro1, Kimberly P. Luttik1, Qiu T. Ruan1,2, Megan K. Mulligan3

1.Laboratory of Addiction Genetics, Department of Pharmacology and Experimental Therapeutics and Psychiatry, Boston University School of Medicine 2. Ph.D. Training Program in Biomolecular Pharmacology, Department of Pharmacology and Experimental Therapeutics, Boston University School of Medicine 3.Department of Genetics, Genomics, and Informatics, University of Tennessee Health Science Center

Dopamine D2 receptor overexpression in the nucleus accumbens core indirect pathway increases activity-based anorexia selectively in female mice

ABSTRACT. Anorexia nervosa (AN) is an eating disorder observed predominantly in females that is characterized by hypophagia, weight loss, and compulsive exercise. Increased dopamine D2/D3 receptor binding in the anteroventral striatum has been previously reported in AN. Activity-based anorexia (ABA) refers to the hyperactivity and hypophagia exhibited by rodents exposed simultaneously to running wheels and scheduled feeding, and provides a rodent model for maladaptive behaviors in AN. We virally overexpressed D2Rs on indirect striatal pathway neurons of the nucleus accumbens (NAc) core (D2R-OENacInd), which endogenously express D2Rs, and tested mice of both sexes in the open field and ABA paradigms. D2R-OENacInd did not alter baseline bodyweight, but increased locomotor activity in the open field across both sexes. In addition, D2R-OENacInd mice of both sexes consumed more food than controls when food and running wheels were continuously available during the baseline period of the ABA paradigm. Yet paradoxically, when food was available only 7 hours a day during the restriction phase of ABA, female, but not male, D2R-OENacInd mice showed robust reductions in food intake and survival. Female D2R-OENacInd mice also showed reduced bodyweight, increased wheel running activity, and increased food anticipatory activity. The only effect of D2R-OENacInd on male mice during restriction was a small increase in wheel running, which began late in the restriction period. Our findings indicate that D2R-OENacInd selectively increases ABA behavior in female, but not male, mice. D2R-OENacInd may play a causal role in the maladaptive feeding and exercise behaviors observed in AN patients.

Amanda C Welch BA1, Jonathan A. Javitch2,3, Matthew S McMurray PhD4, Christoph Kellendonk2, Stephanie C Dulawa PhD1*

1Department of Psychiatry, University of California, San Diego, La Jolla, CA 92093, USA 2Departments of Psychiatry and Pharmacology, Columbia University, New York, NY, 10032 3Division of Molecular Therapeutics, New York State Psychiatric Institute, New York, NY, 10032 4Department of Psychology, Miami University, Oxford, OH 45056, USA

Taste reward circuitry in women remitted from anorexia nervosa and bulimia nervosa: hunger, satiety, and the motivation to eat

ABSTRACT. Eating disorders are serious and difficult-to-treat psychiatric disorders that may involve altered motivation to eat. Typically, hunger enhances, while satiety decreases, reward sensitivity, yet individuals with anorexia nervosa (AN) restrict eating despite emaciation, and individuals with bulimia nervosa (BN) engage in episodes of binge eating, marked by loss of control and eating despite fullness. In a series of studies, we investigated whether AN and BN are associated with abnormal food reward response when hungry and fed in a neural circuit involved in translating taste signals into motivated behavior. Twenty-six women remitted from AN (RAN; to reduce confounding effects of malnutrition), 26 women remitted from BN (RBN) and 22 control women (CW) were administered water and sucrose during 2 counterbalanced fMRI visits, one after a 16-hr fast and one after a standardized breakfast. As expected, CW were more responsive to taste when hungry versus fed. Group (RAN, CW) x Condition (hungry, fed) interactions in the ventral caudal putamen and insula indicated RAN had a decreased brain response when hungry. In contrast, Group (RBN, CW) x Condition (hungry, fed) interactions in the ventral caudal putamen and amygdala indicated increased CW brain response when hungry, but RBN response did not differ between conditions. RBN also responded more than CW in the amygdala when fed. Failure to integrate taste information with motivational (ventral caudal putamen [in AN and BN], amygdala [in BN]) and homeostatic (insula [in AN]) drives may promote food avoidance and diminished drive to eat in AN and binge eating in BN.

Christina E Wierenga1, Amanda Bischoff-Grethe1, Alice V Ely2, Laura A Berner1, Walter H Kaye1

1Department of Psychiatry, University of California San Diego, San Diego CA, USA Department of Neuroscience, 2Christiana Care Health System, Department of Heart and Vascular Care, 4755 Ogletown-Stanton Rd, Newark DE 19718 Funding Support: Supported by NIH grants R01-MH042984-17A1, R01-MH042984-18S1, 5T32MH018399-28, the Wismer Foundation, and the Price Foundation.

Genome-wide association study of anorexia nervosa implicates metabolic and psychiatric origins

ABSTRACT. Anorexia nervosa (AN) is a severe eating disorder characterised by pathological eating behaviour and in certain cases by higher physical activity accompanied by low body fat and fat-free mass. Over the last two decades, family and twin studies have shown that AN has a considerable heritable component with heritability estimates ranging from about 40 to 60%. Genome-wide association studies (GWASs) have yielded eight independent genomic loci associated with AN and its single nucleotide-based heritability has been estimated at 11-17%, indicating a polygenic trait. Analyses partitioning the heritability indicated the involvement of central nervous tissues and cell types in AN. Bivariate linkage disequilibrium score regression (LDSC) can estimate the amount of shared genomics between two traits: Our LDSC analysis showed genomic overlap between AN and psychiatric traits and disorders, such as obsessive-compulsive disorder (OCD), major depressive disorder (MDD), and anxiety, as expected by its clinical comorbidity profile. Surprisingly, AN showed significant negative genetic correlations with anthropometric traits, including body fat percentage and body mass index (BMI), indicating that genomic variants that predispose to lower body mass may also increase liability for AN. Complementing these findings, we also reported genomic overlap between AN and metabolic traits, such as fasting insulin and glucose concentrations as well as high-density lipoprotein concentrations, encouraging a reconceptualization of AN as both a psychiatric and metabolic disorder. Extending these findings by estimating sex-specific genetic correlations, we were able to demonstrate that body fat percentage in females is more highly correlated with AN than in males, suggesting a set of genomic variants associated with body fat percentage in females also operative in AN that potentially contributes to the extreme sex bias observed in its prevalence.

Christopher Huebel, MD, MSc

Social, Genetic & Developmental Psychiatry Centre, Institute of Psychiatry, Psychology & Neuroscience, King’s College London, UK UK National Institute for Health Research (NIHR) Biomedical Research Centre, South London and Maudsley Hospital, London, UK Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, Stockholm, Sweden

11:00-11:30Coffee Break
11:30-12:30 Session 7: Outstanding Travel Awardees

Outstanding Travel Awardees

CLIP-seq analysis of the RNA binding protein hnRNP H in striatum following methamphetamine administration in Hnrnph1+/- mice

ABSTRACT. Hnrnph1 (heterogeneous nuclear ribonucleoprotein H1) is a quantitative trait gene for reduced methamphetamine (MA) behavioral sensitivity. Mice with heterozygous 16-bp deletion in the first coding exon of Hnrnph1 (Hnrph1+/-) showed reduced sensitivity to the stimulant, rewarding, reinforcing effect of MA as well as a decrease in MA-induced dopamine release relative to the wildtype. While accumulating literature indicates a role of Hnrnph1 in neurodevelopment, there is very little known about the mRNA targets of hnRNP H in the brain or the in vivo neurobehavioral function of this RNA binding protein. Given the very modest effects we previously observed on the number of dopaminergic neurons and their forebrain projections, we have since hypothesized that there is an active, drug-induced cell biological mechanism by which Hnrnph1 deletion decreases MA-induced dopamine release and behavior. Therefore, we examined the change in RNA targets of hnRNP H in response to MA. We optimized and performed cross-linking immunoprecipitation coupled with high-throughput sequencing (CLIP-seq) to reveal hnRNP H-RNA interactions in the striatum (a brain region involved in addiction) of both wildtype and Hnrnph1+/- at baseline and in response to an acute dose of MA (2 mg/kg i.p.). CLIP-seq involves the use of ultraviolet irradiation to generate covalent bond between RNA and proteins that are in close contact. An antibody specific to hnRNP H was used to immunoprecipitate the protein-RNA complex followed by RNA extraction and reverse transcription of the extracted RNA into a cDNA library to be sequenced. This is the first CLIP-seq study to examine drug-induced changes in protein-RNA interactions in a specific, functionally relevant brain region and we expect it will shed light on the molecular mechanisms through which hnRNP H regulates methamphetamine-induced dopamine release and addictive behaviors.

Qiu T. Ruan1,2, Michael A. Rieger3, Jacob A. Beierle1,2, Melanie M. Chen1, Karen Zheng1, Amarpreet Kandola1, W. Evan Johnson4, Joseph D. Dougherty3, and Camron D. Bryant1,2,5

1Biomolecular Pharmacology Training Program, Department of Pharmacology and Experimental Therapeutics, Boston University School of Medicine; 2Transformative Training Program in Addiction Science, Boston University School of Medicine; 3Department of Genetics, Washington University School of Medicine; 4Department of Medicine, Computational Biomedicine, Boston University School of Medicine; 5Department of Psychiatry, Boston University School of Medicine

Amygdala NPY circuits are critical for the development of accelerated obesity under chronic stress

ABSTRACT. Neuropeptide Y (NPY) exerts powerful feeding related functions in the hypothalamus. However, NPY is also present in extra-hypothalamic nuclei, however their influence on energy homeostasis is unclear. Here we uncover a previously unknown feeding stimulatory pathway that is activated under conditions of stress in combination with calorie dense food with NPY neurons in the central amygdala (CeA) being responsible for an exacerbated response to a combined stress and high fat diet intervention. CeA NPY neuron specific Npy overexpression mimics the obese phenotype seen in a stress/HFD model, which is prevented by the selective ablation of Npy. Using food intake and energy expenditure (EE) as readout we demonstrate that selective activation of CeA NPY neurons results in increased food intake and a decrease in EE, which requires the presence of NPY. Mechanistically it is the diminished insulin signalling capacity on CeA NPY neurons under stress combined with HFD conditions that leads to the exaggerated development of obesity. Additionally, transcriptome analysis of CeA NPY specific neurons by using translational affinity purification assay (TRAP) with Next-Generation sequencing revealed feeding and stress related markers being dramatically altered during the post-stress period.

Chi Kin Ip1,2, Lei Zhang1,2, Aitak Farzi1,2, Ireni Clarke1, Felicia Reed1, Yan-Chuan Shi1,2, Ronaldo Enriquez 1, Yue Qi1, Chris Dayas3, Bret Graham3, Denovan Begg4, Jens C Brüning5, Diana Hernandez-Sanchez1, Ramon Tasan6, Günther Sperk6 and Herbert Herzog1,2

1Neuroscience Division, Garvan Institute of Medical Research, 384 Victoria Street, Darlinghurst, Sydney, NSW, 2010, Australia; 2Faculty of Medicine, University of New South Wales, Sydney, NSW 2052, Australia; 3School of Biomedical Sciences & Pharmacy, University of Newcastle, NSW Australia; 4School of Psychology, University of New South Wales, Sydney, NSW, 2052, Australia; 5Max Planck Institute for Metabolism Research, Cologne, Germany; 6Department of Pharmacology, Medical University Innsbruck, 6020 Innsbruck, Austria.

Alcohol causes lasting transcriptomic changes in the Drosophila mushroom body

ABSTRACT. The characterization of dynamic transcriptional responses in specific neurons is key to understanding organismal behavior. RNA sequencing data can help reveal the plasticity and specificity of differentially expressed transcripts and genes. Here, we used Drosophila’s genetic accessibility to investigate whether repeated alcohol exposures have long-lasting effects on the active transcriptome of memory-encoding mushroom body neurons, and whether effects change when alcohol is paired with an odor cue. Statistically significant changes were experience-dependent and occurred more at the transcript, and not gene, level. Further gene ontology analysis suggested enrichment for genes known to be alternatively spliced. This suggests that alternative splicing is important for memory encoding and changes after repeated alcohol exposure. The functional implications and specificity of this splicing is currently being investigated. Ultimately these findings suggest a layer of molecular plasticity through which alcohol could influence memory formation and alcohol-associated behaviors.

1Department of Biological Sciences, Southern Illinois University Edwardsville, PO Box 1651, Edwardsville, IL 62026. 2Washington University in Saint Louis MSTP, Washington University, Box 8226, Saint Louis, MO 63110-1093. 2Department of Neuroscience, Brown University, Box GL-N, Providence, RI 02912.

12:30-13:30Lunch Break
13:30-15:30 Session 8: Symposium 2

Laterality and cognition

Colony-level lateralisation of forelimb movements in wood ants

ABSTRACT. Lateralised behaviour was once thought to be a uniquely human trait but more recent work has revealed its presence in other vertebrates and in invertebrates. Insects have been shown to be lateralised in a variety of behaviours including forelimb reaching. The Hymenoptera (bees, wasps, ants) have emerged as a model system in which to study the evolution of lateralised behaviour because it contains species with a different grades of social organisation from solitary and eusocial that have evolved multiple times. This permits direct assessment of how conflict and co-operation among conspecifics contributes to the evolution of laterality. Previous studies have linked eusociality to the presence of population-level laterality but have ignored the presence of colonies in eusocial species such as bees and ants. Our game theoretic and Bayesian models predict that colony-level laterality should be present but also predict that such laterality will be weak, and that colonies in which all individuals were lateralised in the same direction would be punished because of predictability. By assessing the forelimb reaching movements of individual ants, we show that colony-level laterality does exist in the wood ant, Formica rufa, and is weak; colonies typically contain individuals with only a slight bias in forelimb use. Our findings explain why so many behaviours in social insects show relatively weak laterality and provide experimental evidence supporting colony-level laterality, which has previously been overlooked.

Jeremy E. Niven School of Life Sciences, University of Sussex, Falmer Brighton BN1 9QG, UK

Handedness and neurodevelopmental disorders: a genetic approach

ABSTRACT. Filippo Abbondanza1, Silvia Paracchini1

The human brain appears symmetric, but the two hemispheres are functionally and structurally asymmetric. Handedness is the most accessible index of lateralization, and it partially reflects brain asymmetries. Worldwide, ~10% of individuals are left-handed, and an increase of non-right handedness frequency has been reported in neurodevelopmental conditions including dyslexia, schizophrenia and autism. These disorders are characterised, among others features, by atypical brain asymmetries. These findings highlight the potential of handedness to investigate brain structure and neurodevelopmental disorders.

Genetic studies of handedness have largely failed, with two exceptions. A first GWAS found an association between PCSK6, implicated in left-right body axes, and relative hand skills (pegboard test) in a dyslexia cohort. In the general population, genes involved in structural asymmetries and cytoskeleton dynamics were highlighted. A second GWAS in a large cohort identified four SNPs - in genes involved in microtubule growth, essential for cytoskeleton maturation - statistically associated with the categorical definition of handedness.

Building on these findings, this talk will address the effect of phenotypic measurements as well as follow up genetic studies. The relationship of different handedness/lateralisation indexes (including eye and leg preference) are investigated in large datasets (N~10,000). This analysis will inform genetic studies currently underway. In particular, a large meta-analysis of GWAS data for laterality measures is being conducted enriching the sample set with individuals presenting neurodevelopmental disorders. These data will contribute to our understanding of the role of asymmetries in neurodevelopment.

1: School of medicine, University of St Andrews, UK

Behavioral laterality predicts fear avoidance responses but does not predict anxiety-related behavior in zebrafish (Danio rerio)

ABSTRACT. Introduction: Behavioral laterality is an evolutionarily conserved characteristic which is observed at populational level in humans. Zebrafish (Danio rerio) is an increasingly popular animal model in neuroscience due its high physiological homology to mammals. The objective of this study was to identify zebrafish with strong behavioral lateralization using an unconditioned y-maze protocol and evaluate if laterality bias played a role in conditioned fear response and anxiety-like phenotypes. Methods: 101 adult zebrafish were assessed in the y-maze for 1 hour. Behavioral lateralization was considered when an animal presented >60% bias for left or right turn. Following y-maze characterization, animals were pair housed for 24h and further tested on Pavlovian fear conditioning or novel tank diving task (NT), based on previously studies. Results: Zebrafish present robust behavioral lateralization in the y-maze (left-biased 27.18%, right-biased 27.18 % and non-biased 45.63%). Left (p<0.001) and right-bias (p<0.005) fish showed significantly more repetitions and lower number of alternations compared to the non-biased animals. In the conditioned fear test, fish that showed behavioral lateralization showed a significantly stronger avoidance response to a shock stimulus than non-biased animals (p<0.05). No significant bias effect was observed in the NT. Conclusions: Our data suggest that, in zebrafish, behavioral lateralization is related to different behavioral phenotypes in the y-maze and predicts performance on a conditioned fear test. Overall, our novel findings suggest that the y-maze test can be a valuable protocol to measure behavioral lateralization and could be used to further understand the evolutionary origins and functional relevance of left-right asymmetry.

Fish as animal models to explore the relation between anatomical and functional asymmetries

ABSTRACT. Studies over the past few decades have shown that brain lateralization is not exclusive to humans but is rather widespread in animals. In recent years fish have become valuable models to address brain lateralization at different levels of complexity: from genes to behaviour. For instance, behavioural studies have shown that the advantages of having an asymmetric brain, such as the possibility of processing multiple information in parallel, may be balanced by some disadvantages associated with poorer interhemispheric integration. However, the impact of brain lateralization on behaviour was not investigated leaving open the question of how these two aspects are linked. With respect to this issue, research on zebrafish has provided important insights into the relation between anatomical and functional asymmetries showing how altered brain lateralization affects behaviour.

ME Miletto Petrazzini1, M Dadda2

1School of Biological and Chemical Sciences, Queen Mary University of London, London, UK, 2 Department of General Psychology, University of Padova, Padova, Italy.

Spontaneous and light induced brain lateralization of c-Fos expression in the newly-hatched chick

ABSTRACT. Different forms of embryonic stimulation, such as temperature changes or acoustical experiences, induce long-lasting effects on the baseline level of c-Fos expression in different brain regions of domestic chicks (Gallus gallus). In the avian brain, thanks to the asymmetrical position in the egg determined by the Nodal cascade, embryonic light stimulation reaches selectively the left hemisphere (right-eye), inducing brain and behavioral asymmetries later in development. Here we investigated the role of embryonic light stimulation on the pattern of spontaneous c-Fos expression in different brain regions of the two hemispheres. We estimated c-Fos immunoreactivity in septum, intermediate medial mesopallium, hippocampus and preoptic area of the hypothalamus of chicks hatched from either dark-incubated or light-stimulated eggs. We found c-Fos expression to be asymmetrically modulated by light in a region-dependent fashion. Septum showed higher c-Fos expression in the left hemisphere only after embryonic light stimulation, whereas preoptic area showed a spontaneous right lateralization only in the absence of stimulation. Hippocampus and intermediate medial mesopallium did not show any significant lateralization nor any difference between the two conditions. Cell counting performed with DAPI staining revealed that differences found in c-Fos expression were not related to underlying differences in the overall cell densities. We thus confirmed the crucial role of environmental factors, such as light in embryo, on the development of brain lateralization, showing that it also affects c-Fos expression. Interestingly, however, we provided evidence that some forms of brain asymmetries might be genetically predisposed or at least independent from the effect of light exposure.

E Lorenzi1, U Mayer1, O Rosa-Salva1, A Morandi-Raikova1, G Vallortigara1

1CIMeC, University of Trento, Rovereto, TN, Italy Funding Support: European Research Council under the European Union’s Seventh Framework Programme (FP7/2007-2013)/ Advanced Grant ERC PREMESOR G.A. [n_ 295517] to G Vallortigara

What is the role of new-neurons in the development of individual behaviour?

ABSTRACT. J Bogado-Lopes1,2, F Ehret1,2, AN Grzyb1,2, AE Rünker1,2, G Kempermann1,2

The interaction of individuals with their environment leads to the development of distinct behavioural patterns. Previously, we showed that isogenic mice kept in an enriched environment (ENR) established divergent and stable social and exploratory trajectories. Remarkably, the amount of exploratory activity, measured as roaming entropy (RE), correlated positively with adult hippocampal neurogenesis (AHN), a cellular plasticity mechanism in the hippocampus. We hypothesised that the feedback between activity (and hence experience of the environment) and brain plasticity, including AHN, is a core mechanism underlying brain individualization in ENR. To investigate whether disruption of AHN would compromise the exploratory activity and individualisation processes, we here used cyclin D2-ko mice with constitutively suppressed AHN (but normal hippocampal development), and their wild-type littermates (n = 40). Animals were housed together for 3-months in a novel large ENR enclosure consisting of 70 connected cages equipped with radio antennae for longitudinal tracking. Their cognitive performance was evaluated in the Morris Water Maze task (MWM) and AHN levels were assessed using BrdU labeling. We confirmed that the number of BrdU+ cells correlated with RE in the wild-type animals, and cyclinD2-ko mice had impaired performance in the reversal phase of MWM. Whereas wild-type animals developed stable exploratory trajectories, the behaviour of cyclinD2-ko mice remained more random. Furthermore, different patterns of correlations between exploratory behavior, cognitive performance and AHN were observed in wild-type and knockout mice. Together, these results suggest that adult neurogenesis may have a crucial role at the individualisation of brain-related phenotypes.

1German Center for Neurodegenerative Diseases (DZNE) Dresden, 2Center for Regenerative Therapies TU Dresden (CRTD), Technische Universität Dresden, Dresden, Germany. Funding Support: Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES), Brazil.

15:30-17:30 Session 9: Poster Session

Poster Session I 

Odd Number Posters

P1 – Reward sensitivity in Hnrnph1+/- mice following acute methamphetamine administration as measured via intracranial self-stimulation

ABSTRACT. Kristyn N. Borrelli1, A. Carlezon Jr2, Elena H. Chartoff2, Camron D. Bryant1

1Department of Pharmacology and Experimental Therapeutics, Boston University School of Medicine, Boston, MA; 2McLean Hospital, Department of Psychiatry, Harvard Medical School, Belmont, MA

Psychostimulant addiction is a heritable substance use disorder whose genetic basis is largely unknown. Several quantitative trait loci (QTL) in mice have been linked to addiction-related behaviors. The genes underlying these loci could provide clinical insight to the contribution of genetic factors in addictive disorders. We previously mapped and validated Hnrnph1 (heterogeneous nuclear ribonucleoprotein H1) as a quantitative trait gene underlying variance in methamphetamine (MA)-induced locomotor activity. Mice heterozygous for a frameshift deletion in coding exon IV of Hnrnph1 (Hnrnph1+/-) display decreased locomotor activity in response to MA compared to their wild-type littermates (Hnrnph1+/+). Microdialysis studies additionally show reduced MA-induced dopamine release in Hnrnph1+/- mice. We employed Intracranial self-stimulation (ICSS), an operant behavioral paradigm commonly used to assess shifts in sensitivity to stimulation of the dopaminergic mesolimbic reward circuit, to assess changes in ICSS responding following acute MA administration in Hnrnph1+/- mice. Using stereotaxic surgery, we implanted a unilateral, stimulating electrode into the medial forebrain bundle (MFB). Activation of these fibers produces robust brain stimulation reward (BSR). Mice were trained on a fixed ratio 1 (FR1) schedule to receive MFB stimulation for each 1/4 turn of a response wheel. Increasing doses of MA were then administered every other day to detect MA-induced changes in BSR-associated reinforcement. We identified sex- and dose-dependent changes in the rate of ICSS responding in Hnrnph1+/- mice compared to wild-type littermates following acute MA administration. These findings support our previous work suggesting that Hnrnph1 dysfunction disrupts the rewarding properties of MA, further implicating this RNA binding protein in reward circuitry modulation.

P3 – Role of epigenetic mechanisms in intergenerational effects of anesthesia with sevoflurane in young adult rats

ABSTRACT. Each year millions of patients have surgeries under general anesthesia. Anesthetic exposure in early childhood or old age is linked to neurocognitive deficiencies. The adverse effects of anesthetics in young adults remain largely unexplored and there is practically no information on vulnerability of their future offspring. To investigate potential intergenerational effects of young adult anesthetic exposure, Sprague-Dawley postnatal day 56 rats (generation 1, G1) were anesthetized with 2.1% sevoflurane on 3 alternate days and mated 25 days later to produce offspring (G2). The G1 males and females had elevated systemic corticosterone, but only males had decreased hypothalamic cell surface K+-2Cl- (KCC2) Cl- exporter expression 1 h after the last sevoflurane exposure. Only G1 males exhibited persistent neurobehavioral deficiencies, exaggerated hypothalamic-pituitary-adrenal (HPA) axis responses to restraint, elevated levels of testosterone and reduced testis weight. Changes in hypothalamic-pituitary-testicular (HPT) axis functioning and expression of hypothalamic aromatase and estrogen receptors were consistent with a role for systemic testosterone/brain estradiol in G1 sex-specific effects of sevoflurane. Only the male offspring (G2) of exposed parents exhibited neurobehavioral deficiencies, but had unaltered HPA and HPT axis functioning. Finally, down-regulated Kcc2 expression in G1 and G2 male hypothalamus and hippocampus, and hyper-methylated Kcc2 promoter in G1 sperm and ovary and G2 male hypothalamus and hippocampus support the involvement of epigenetic mechanisms in sevoflurane’s intergenerational effects. Repeated exposure of young adult rats to sevoflurane results in sex-specific central and systemic abnormalities, some of which are passed to offspring, which could increase risk for disease later in life.

LS Ju1, JJ Yang1, N Xu1, J Li1, TE Morey1, N Gravenstein1,2, CN Seubert1, B Setlow2,3, and AE Martynyuk1,2

Department of Anesthesiology1, the McKnight Brain Institute2, and Department of Psychiatry3, University of Florida College of Medicine, Gainesville, FL, USA.

Funding Support: Supported by the National Institutes of Health (R01NS091542 and R01NS091542-S to AEM), the Escher Autism Fund (AEM), the I. Heermann Anesthesia Foundation (LSJ), and the Jerome H. Modell, M.D., F.A.H.A. Endowed Professorship, Gainesville, Florida (NG).

P5 – The Role of Glutamate-related Proteins in Genetic Risk for High Methamphetamine Intake

ABSTRACT. The methamphetamine (MA) high drinking (MAHDR) and MA low drinking (MALDR) lines were selectively bred for voluntary MA consumption, and thus represent a model of differential genetic risk for MA intake. These lines differ in accumbal expression of a number of glutamate-related proteins. The MAHDR line expresses higher levels of the metabotropic glutamate receptor 5 (mGluR5) and the related scaffolding protein, Homer2a/b. Homer2a/b and mGluR5 have been implicated in intake and rewarding effects of other addictive drugs. There are no drugs that target Homer2a/b; however, there are drugs that target mGluR5, although they have never been tested in a model of high genetic risk for MA addiction, such as the MAHDR mice. Expression differences for glutamate-related proteins were found in one replicate of the MA drinking lines, and it is important to confirm these differences in an independent replicate. The nucleus accumbens from a separate replicate of MAHDR and MALDR lines was obtained and the same proteins analyzed. Expression of Homer2a/b was approximately 1.5x greater in MAHDR than MALDR mice, a difference nearly identical to the difference in the previous replicate. Results for mGluR5 are unclear at this time; however, when two highly selective mGluR5 negative allosteric modulators were tested in MAHDR mice in which MA drinking had been established, neither significantly altered established MA intake levels. These results provide additional evidence of a role for Homer2a/b in MA intake, and suggest that mGluR5 may not be an effective treatment target for individuals with high genetic risk for MA addiction.

JRK Mootz1, TJ Phillips1,2 1Oregon Health & Science University, 2Veterans Affairs Health Care System, Portland, OR, USA. Funding Support: Department of Veterans Affairs I01BX002106, NIH NIDA P50DA018165, U01DA041579, and R01DA046081

P7 – Light duration changes locomotor response dependence on HPA axis signaling

ABSTRACT. When vertebrates face acute stressors, their bodies rapidly undergo a repertoire of physiological and behavioral adaptations, which is termed the stress response (SR). These adaptations are mediated via the interaction of glucocorticoids and their cognate receptors following hypothalamic-pituitary-adrenal (HPA) axis activation. Rapid SR is observed within minutes of encountering a stressor and the rapid time domain rules out genomic responses that require gene expression changes. Using larval zebrafish, we showed that rapid locomotor response is elicited in acute light changes (acclimation in infrared (darkness)—1-min white light illumination—back to infrared) and that such response is dependent on mc2r (adrenocorticotropic hormone receptor) and nr3c1 (glucocorticoid receptor), but not on nr3c2 (mineralocorticoid receptor). However, when we tested larval zebrafish with 7.5-min light-dark repeat assays (7.5-min white light illumination—7.5 min infrared repeated four times), we found that both mc2r and nr3c1 homozygous mutants showed equivalent locomotor response to wild-type (WT) fish. This 7.5-min repeat assay is commonly used in the zebrafish community and described as eliciting stress- or anxiety-like behavior. Nonetheless, our results indicate that this locomotor response is not dependent on key HPA axis receptors (mc2r or nr3c1). Since stress is often operationally defined as increased HPA axis activity, we propose that this 7.5-min repeat assay should be more carefully characterized and defined before being reported as stress-like behavior. We want to further explore and understand how similar stimuli show altered dependence on HPA axis signaling for observed locomotor responses based on changes in duration of the stimuli.

HB Lee, AN Sigafoos, and KJ Clark

Department of Biochemistry and Molecular Biology, Mayo Clinic, 221 Fourth Ave. SW, Rochester, MN 55902

P9 – Molecular and neural mechanisms of alcohol-induced sleep disruption in Drosophila

ABSTRACT. Exposure to alcohol is known to trigger homeostatic adaptations in the brain that lead to the development of tolerance and dependence. These adaptations are also believed to be the root of a series of disturbances in sleep patterns that often manifest during the development of alcoholism and can have significant clinical and economic consequences. Unfortunately, the genetic pathways that control the effects of alcohol on sleep homeostasis are currently unknown, thus limiting our efforts to find effective treatment. Here, we report the use of Drosophila melanogaster as a biological model to understand the molecular underpinnings of the effects of alcohol on the neuronal substrates that control sleep. We show that in Drosophila, acute alcohol exposure causes disturbances in sleep patterns that resemble those described in mammals. These disturbances include an increase in total sleep duration, decrease sleep latency, as well as an increased number of sleep episode per day (fragmented sleep). Furthermore, we show that genes implicated in the neural adaptations behind alcohol tolerance, are also implicated in the regulation of sleep cycles. Manipulation of these alcohol responsive genes in the neuronal circuits involved in sleep/wake regulation in Drosophila significantly reduces the effects of alcohol on sleep patterns. Our results suggest that sleep and alcohol neuroadaptation share a common regulatory mechanism. We believe that the integration of genetic analyses with physiological modulation of neural activity within specific sleep circuits has tremendous potential to uncover the functionally relevant molecular targets whose action contributes to the deleterious effect of alcohol on sleep.

ME Ramirez-Roman1, A Anqueira-Gonzalez1, JL Agosto, A Ghezzi1 1Department of Biology, University of Puerto Rico, Rio Piedras; San Juan, PR 00931

P11 – Transcriptomic analysis of differential treatment of Qi-dysregulation phenotypes revealed the participation of neuroengery in depression using Balb/cJ mouse strain

ABSTRACT. Stratified treatment by identification and treatment with specific antidepressants remain a challenge in the western medicine. Traditional Chinese Medicine (TCM) is a personalized medicine in which the diagnosis and treatment is based on identification of dysfunctional patterns, which may be shared by different diseases. The most prevalent TCM dysfunctional patterns in depression clinically include Qi stagnation, the repression of energy and Qi deficiency, the deficiency of energy. Previously we shown Balb/cJ mouse strain demonstrated both Qi-stagnation-like and Qi-deficiency-like phenotypes following chronic stress. Here, we found treatment with Qi-tonifying formula Sijunzi showed better efficacy than Qi-stagnation unblocking formula Yueju or regular antidepressant fluoxetine. Here, to further understand the genetic architecture underlying depression/antidepressant activity, we made transcritpomic sequencing and bioinformatic analysis of the prefrontal cortex, the crucial depression regulation region, on chronically-stressed mice, followed with these drug treatment. All three treatment groups showed different patterns of normalization of the gene expression perturbed by stress, with only 3 genes that were shared by three groups. Interestingly, two of the genes tkl2 and lct both process lactate, the important neuroenergenic molecule to maintain the normal function of the neurons. Furthermore, Sijunzi normalized additional lactate processing gene. Accumulating evidence suggests lactate and neuroengery were associated with depression, and depressive patients showed increased lactate concentration. We using unbiased systematic approaches, detected novel genes for lactate pathway implicated in depression pathogenesis, and potentially useful as the key target for treatment. This also suggests that the neural energy may serve as the common pathway underlying depression and supports the scientific connotation of the traditional medicine in treating depression.

Liantiao Xu 1,Wenjia Li1, Houxi Xu2, Wenda Xue1, Gang Chen 3, 4*

1 Center for Translational Systems Biology and Neuroscience and Key Laboratory of Integrative Biomedicine for Brain Diseases, Nanjing University of Chinese Medicine, Nanjing 210023, China; 2 Nanjing University of Chinese Medicine, Nanjing 210023, China 3 Interdisciplinary Institute for Personalized Medicine in Brain Disorders and Research Center for TCM Fang-Zheng, Jinan University, Guangzhou, 510632, China. 4 Co-innovation Center of Neuroregeneration, Nantong University, Nantong, Jiangsu 226001, China. Support: by the National Science Foundation of China (81874374) .

P13 – Examining the Association Between Polygenic Risk Scores for Neuroticism and Extraversion, Cognitive Biases and Psychopathology Among Adolescents

ABSTRACT. Adolescence is a critical developmental period regarding individuals’ mental health. Studies have shown that personality traits such as neuroticism, extraversion and cognitive biases are involved in the onset and maintenance of psychiatric disorders. While genetic variants have been shown to influence each of these factors, the extent to which they are caused by the same genetic factors remains unknown. We aimed to test potential associations between polygenic risk scores for neuroticism and extraversion obtained from the GPC (Genetics of Personality Consortium) and mental health and cognitive biases. To examine this, we used whole genome data and phenotypic data including psychological self-report measures (e.g. depression, anxiety) and performance on a range of attention, memory and interpretative bias tasks from 390 adolescents as part of the CogBIAS longitudinal study at Oxford University. Multilevel modelling across three time points revealed few associations between genetic risk for neuroticism and psychiatric disorders or cognitive biases. However, there were significant associations between extraversion and several of the anxiety subtypes as well as cognitive biases; most notably the memory bias. We also found evidence for time-by-genotype interactions for memory biases. These interactions suggested that those with a high polygenic score for extraversion develop an increasingly positive memory bias during adolescence. Our findings provide some potential causal pathways between genetic risk and protective factors and psychopathology, that if replicated, may represent novel targets for prevention and intervention.

Sumeyye Ozkaya1, John Vincent1, Charlotte Booth2, Anabelle Songco2, Sam Parsons2, Lauren Heathcote2, Elaine Fox2, Robert Keers1

1Department of Biological and Chemical Sciences, Experimental Psychology, Queen Mary University London, London, E1 4NS, UK 2Department of Experimental Psychology, University of Oxford, New Richards Building, Oxford, Headington OX3 7LG, UK

P15 – Different social behavior and oxytocin responses to acute methamphetamine treatment in juvenile female rats perinatally exposed to stress and/or drug administration

ABSTRACT. Methamphetamine (MA) is an addictive psychostimulant, often abused by drug addicted women during pregnancy. The offspring of drug-addicted mothers are often exposed to perinatal stressors. The present study examines the effect of perinatal stressors and drug exposure on plasma oxytocin (OXY) levels and social behavior in female progeny. Rat mothers were divided into three groups according to drug treatment during pregnancy: intact controls (C); saline (SA, s.c., 1 ml/kg); MA (s.c., 5 mg/kg). Litters were divided into four groups according to postnatal stressors lasting from PD1 to 21: non-stressed controls; maternal separation; maternal cold-water stress; maternal separation plus cold-water stress. On postnatal day 30, acute MA or SA were administrated and female progeny was exposed to Social play test lasting 15 minutes. Immediately after Social play test, the rats were sacrificed. Trunk blood was collected and plasma OXY was measured by specific ELISA after extraction. Our results showed that acute MA administration changes the social play and social exploration differently. Acute MA also significantly increases plasma OXY levels in juvenile female rats; this effect was observed in prenatally intact rats only. Prenatal exposure of rats to mild stressor of daily SA injection prevented both acute MA induced OXY stimulation and also stress induced OXY inhibition. Although postnatal MA and stress exposure exert opposite effects on OXY release in juvenile rats, our data point out the modulatory role of prenatal mild stress in OXY response to postnatal stressors or MA treatment.

A Holubová1, S Poništ1, J Jurčovičová1, R Šlamberová1

1Department of Physiology, Third Faculty of Medicine, Charles University, Prague, Czech Republic Funding support: PROGRES Q 35, GAUK 850317, 260388/SVV/2019 from Charles University, 18-09296S from the Grant Agency of the Czech Republic, PharmaBrain CZ.02.1.01/0.0/0.0/16_025/0007444 funded from OP VVV.

P17 – Early-life low-level chronic lead (Pb) exposure alters anxiety-like behavior, but not alcohol intake, in adult C57BL/6J mice

ABSTRACT. Human association studies have found that childhood lead (Pb) exposure is highly correlated with substance use disorder (SUD) in adulthood. Since 2012, the average blood Pb levels (BLL) found among children in lower socioeconomic income environments has generally ranged from 3-5 mg/dL. Although historically lower, these Pb exposure levels may still be sufficient to alter brain and behavior. Here we sought to model such low-level Pb exposure in mice. At weaning (PND 21) C57BL/6J mice were assigned to three-week Pb (30 or 0 ppm) exposure via the drinking water resulting in BLL of 6.6±0.5 and 5.1±0.4 mg/dl in males and females, respectively. Once mice reached adulthood (PND 70±5) they were tested for anxiety- (elevated plus maze) and depressive- (forced swim) like behavior, and then given access to alcohol (20% v/v) for 2hrs per day for three weeks. We hypothesized that mice with early-life low-level Pb exposure would exhibit heightened anxiety- and depressive-like behavior, and consume more alcohol, than their non-Pb exposed counterparts. Early data suggest that although Pb exposure does not alter immobility latency or time in the forced swim task, or limited-access alcohol intake, it significantly decreases open arm entries on the elevated plus maze (p<0.05), suggesting that early-life low-level Pb exposure increases anxiety-like behavior. These results suggest that low-level childhood exposure to Pb may alter the developing brain sufficiently to produce adult changes in overall anxiety, but not necessarily propensity to consume alcohol.

S.L. Boehm II1, 3, M. Hernández1, Y. Zhang1, M. R. Watson1, and G.M. Filippelli2

1Department of Psychology, Indiana University – Purdue University Indianapolis, Indianapolis, IN 46202. 2Department of Earth Sciences, Indiana University – Purdue University Indianapolis, Indianapolis, IN 46202, 3Indiana Alcohol Research Center, Indiana University School of Medicine, Indianapolis, IN 46202. Funding support: Indiana University Addictions Grand Challenge initiative (IU Vice President for Research Office).

P19 – Longitudinal DNA methylation changes related to reinforcement psychopathology in adolescence

ABSTRACT. In recent years, much interest has been focused on epigenetic mechanisms underlying environmental influences related to the development of behaviour and psychopathology. In particular, DNA methylation, one of the key epigenetic processes, has been the central topic of mental health research. While DNA methylation has been associated with environmental influences and the development of psychiatric illnesses, longitudinal methylation changes have not been well described. Current analyses of DNA methylation variations over time have mostly been related to age-related changes. With the advantage of having access to the longitudinal adolescent IMAGEN cohort, our aim is to identify novel DNA methylation patterns over time and relate them to neurobehavioural features and development of psychopathologies. Here I will present our preliminary findings on dynamic changes in methylation patterns identified within the IMAGEN cohort. I will also describe how these dynamic methylation patterns observed relate to environmental influences and neurobehavioural features.

Nicole Tay1, Yan Sun1, Tianye Jia1,2,3, Yun Liu4, Alex Ing1, Zuo Zhang1, Riya Paul5, Bertram Mueller-Myhsok5, Gunter Schumann1

1Centre for Population Neuroscience and Stratified Medicine (PONS) and SGDP Centre, Institute of Psychiatry, Psychology and Neuroscience, King’s College, London, UK; 2Institute of Science and Technology of Brain-inspired Intelligence, Fudan University, Shanghai, China; 3Key Laboratory of Computational Neuroscience and Brain-inspired Intelligence, Fudan University, Ministry of Education, Shanghai, China; 4MOE Key Laboratory of Metabolism and Molecular Medicine, Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Fudan University, Shanghai, PR China; 5 Department of Translational Research in Psychiatry, Max Planck Institute of Psychiatry, Munich, Germany

P21 – Forced swim test and CB-1 receptor expression in hippocampus of offspring of obese male mice

ABSTRACT. Offspring of obese male mice demonstrate impaired metabolism, obesity, and changes of behaviour. We performed a forced swim test (FST) and detected the expression of type 1 endocanabioid receptor (CB1-R) in hippocampus to understand the stress coping strategy to an acute inescapable stress in such animals. Methods: Male C57Bl6/N mice were placed for 12 weeks on either a high fat diet (HFD, 45% kcal fat) to induce obesity or a normal fat diet (LFD, 10% kcal fat) and then mated with females on LFD. Offspring of both parents on LFD formed Group 1 and offspring of males on HFD and females on LFD formed Group 2. Pups were fed regular chow and tested at 1.5 and 6 months. The FST was performed and CB-1R expression was detected in different regions of hippocampus by immunohistochemistry staining. Results: Analysis of FST has shown that all 1.5 month offspring from Groups 1 an 2 demonstrated more “struggling” behaviour than at 6 months. At 1.5 months male offspring from Group 2 demonstrated less “struggling” behaviour than Group 1 male offspring. At 6 months female offspring of Group 2 swam more and floated less than females of Group 1 or the animals of the same group at 1.5 months. Direct parallelism between the results of FST and expression of CB-1R in different regions of hippocampus were not observed. Conclusion: Paternal HFD results in offspring with changed results of FST that are not related to the expression of CB-1R in hippocampus.

Y.Slyvka1, Y. Zang1, G. Sindi1, A.Zontini1, F.V. Nowak1

1Department of Biomedical Sciences, Ohio University, Athens, OH 45701 USA

P23 – The Adult Neurogenesis Map

ABSTRACT. The hippocampus is a key brain structure for learning and memory. It not only processes input from the environment, but also fundamentally influences behaviour. This means that the neural network in the hippocampus is a core part of an information loop connecting environmental stimulus and response. It is particularly intriguing that this special brain region is also home to a population of neural stem cells which allow the environmentally-regulated creation of new neurons, throughout the life of the organism, that add an extra level of flexibility to hippocampal performance. We have previously shown that the regulation of the stem cell pool and the generation of new neurons are under complex genetic control. We also maintain a structured database of all genes reported to affect adult hippocampal neurogenesis in some way. We are now extending this effort to encompass behavioural phenotypes and environmental stimuli. The resulting information is being organised into a structured SBML map to enable interactive browsing and complex searching of the knowledgebase, as well as to provide a platform for predictive modelling. We present here an outline and working draft of the Adult Neurogenesis Map and look forward to community feedback as the project expands.

RW Overall1

1German Center for Neurodegenerative Diseases (DZNE), Dresden, Germany

P25 – The role of ErbB3 binding protein 1 (EBP1) in brain development and gene silencing control in mice

ABSTRACT. ErbB3-binding protein 1 (EBP1) is a well-conserved DNA/RNA-binding protein that is implicated in cell growth, apoptosis, and differentiation. . To define the physiological function of EBP1 in vivo, we generated Ebp1-mutant mice that showed loss of Ebp1 expression. Here, we report that EBP1 is essential for embryonic development including and regulation of transcriptional repression. Loss of Ebp1 in mice results in aberrant organogeneses, including malformation of the brain and death between E13.5 and 15.5 owing to severe hemorrhages, with massive cell death and cessation of cell proliferation. Consistently, mice lacking EBP1 in the central nervous system [Nestin-Cre; Ebp1flox/flox] showed developmental defects of the brain, with substantial neuron loss. Importantly, the Ebp1(-/-) mice demonstrated upregulation of Suv39H1-dependent histone H3 lysine 9 (H3K9) trimethylation and subsequent activation of DNMT1, displaying markedly increased global DNA methylation. Moreover, EBP1 suppressed the transcriptional expression of Dnmt1 by altering the recruitment of RNA polymerase II at its promoter region and also interrupted DNMT1 binding at its target gene, at the survivin promoter region. Our finding uncovers a key role of EBP1 in embryonic development and as a potent co-regulator of gene expression that might coordinate epigenetic modification.

Hyo Rim Ko1, Inwoo Hwang1,2, Taegwan Yun1,2, Eun-Ju Jin1, and Jee-Yin Ahn1,2,*

1Department of Molecular Cell Biology, 2Single Cell Network Research Center, Sungkyunkwan University School of Medicine, Suwon 16419, Korea Funding Support: A grant of the Korea Health Technology R&D Project through the Korea Health Industry Development Institute (KHIDI), funded by the Ministry of Health & Welfare, Republic of Korea (HI17C0227

P27 – Functional characterisation of ADHD-associated gene variants using the zebrafish as an animal model

ABSTRACT. Attention deficit hyperactivity disorder (ADHD) is the most common neuropsychiatric disorder of childhood, affecting around 5% of children worldwide. Individuals are typically diagnosed with high levels of activity, inattention, and impulsivity, which have strong negative impacts on their academic and interpersonal development. Despite research into the genetic background of ADHD uncovering several associated genes, the functional validation of these genes is lacking. To address this, we have investigated the function of two ADHD associated genes to determine their roles in this disorder. These genes are CHMP7, a gene predicted to be functionally relevant to ADHD, and DUSP6, one of the first significant ADHD genome wide association hits. This led us to generate zebrafish mutant lines for chmp7 and dusp6 to examine how variants in these genes contribute to the ADHD phenotype. Individuals homozygous for the ADHD associated variant in CHMP7 have a 33% reduction in CHMP7 transcript. Therefore we investigated activity in heterozygous fish, and demonstrate significantly increased activity compared to their siblings. Similarly, we have examined fish mutants for dusp6 and identified significant increases in activity in homozygous mutant fish compared to siblings. Together these provide the first examples of functional validation for ADHD associated variants from genome wide association studies or functional prediction pathways, and provide insight into the potential mechanisms underlying the ADHD phenotype. I will present functional data confirming the relevance of these genes in the development of ADHD, as well as data exploring the mechanisms underlying their roles in the disorder.

Callum Dark1, Caitlin Williams, Dr Ziarih Hawi2, Dr Janette Tong2, Prof Mark Bellgrove2 and Dr Robert Bryson-Richardson1

1 School of Biological Sciences, 2 School of Psychological Sciences; Monash University, Melbourne, Australia

P29 – Natural polymorphism in protein kinase G modulates functional senescence in D. melanogaster

ABSTRACT. The common fruit fly, Drosophila melanogaster, is a well characterized model for neurological disorders and is widely used to investigate the biology of aging, stress tolerance and pleiotropy. The foraging (for) gene encodes a cGMP-dependent protein kinase (PKG), which has been implicated in several behavioral phenotypes including feeding, sleep, learning and memory, and environmental stress tolerance. We used the well-established Drosophila activity monitor (DAM) to investigate the effects of the conserved NO/cGMP/PKG signaling pathway on functional senescence. Our results show that the polymorphic for gene confers protection during low oxygen stress at the expense of longevity and a decline in locomotor activity with age in D. melanogaster, which suggests a novel role for the PKG pathway in healthy aging and senescence.

Stephanie P. Kelly and Ken Dawson-Scully* Florida Atlantic University, Department of Biological Sciences, Boca Raton, FL, 33431

P31 Using C. elegans social behaviour to investigate genes associated with autism spectrum disorder

ABSTRACT. Autism spectrum disorder (ASD) is characterised by a triad of impairments, one of which is impaired social behaviour. Several different gene mutations are implicated in ASD however it is not clear how these result in behavioural impairment. C. elegans provides a tractable system to investigate the impact of genetic variants on cellular function and relate this to neural circuits that co-ordinate behaviour. We have shown that C. elegans adults elicit a social behaviour in response to progeny1. Using this paradigm, we can probe how genetic variants impact the function of neural circuits that underpin social behaviour. Neuroligin is a synaptic adhesion protein which aids synaptic function. Genetic variations in neuroligin have been shown to be highly penetrant in ASD. The C. elegans genome encodes a single neuroligin orthologue, nlg-1. The nlg-1(ok259) allele is a functional null and has been used in this study to investigate the role of neuroligin in co-ordinating progeny dependent social behaviour. We have identified that nlg-1(ok259) adult worms have an impaired social behaviour in response to progeny. To further our investigations, we have used CRISPR/Cas9 to edit the C. elegans genome to contain an arginine to cysteine amino acid substitution identified in individuals with ASD. In this way we hope to provide further insight into how genetic variations in neuroligin impact on the function of neuronal circuits to cause the behavioural impairments diagnosed in ASD.

Helena Rawsthorne, Umaymah El Ghiffari Barnett, Evie Goss-Sampson, Fernando Calahorro, James Dillon, Vincent O’Connor, Lindy Holden-Dye

1. Scott, E. et al. An oxytocin-dependent social interaction between larvae and adult C. elegans. Sci Rep 7, 10122 (2017). Biological Sciences, University of Southampton, SO17 1BJ. Funding support: The Gerald Kerkut Charitable Trust