ABSTRACT. 1Jiaru Huang, 2Yin Chen, 1Hailou Zhang, 1Gang Chen

Fatigue is a common and important symptom of depression and more resistant to conventional antidepressant treatment. We argued that shared genetics may underlie the co-susceptibility to these two symptoms. We compared two mouse strain Balb/c and 129S1, following different protocols for chronic stress. Fatigue is a typical Qi-deficiency symptom in Traditional Chinese Medicine and usually treated with Qi-tonifying drug Sijunzi-decotion. In the chronic unpredictable mild stress model, we found both Balb/c and 129S1 mice showed depression-like symptoms, including hedonic deficit in sucrose preference and behavior despair. However, only Balb/c mice showed fatigue-like symptoms, including reduction in the strength of grips and the floating time in exhaustive swim test. Exposure to other chronic stress protocols such as chronic social defeat or chronic learned helplessness led to similar results, supporting the significant genetic impacts on the co-susceptibility. Treatment with Sijunzi improved both fatigue and depression-like behaviors selectively in stressed Balb/c mice, but failed to show antidepressant response in stressed 129/S1 mice. Conventional antidepressant fluoxetine was less effective in relieving the fatigue symptom in Balb/c Sequencing the mRNA in the prefrontal cortex in mice exposed to chronic stress and treated with Sijunzi showed both strain-dependent and treatment-dependent impacts. Multiple signaling pathways have been identified. One of the most interesting gene associated with the depression and fatigue co-susceptibility is ACSS3, which has been reported to be associated with both depression and resistant to antidepressant treatment in human GWAS studies, and verification of the role of this gene is under investigation.

1Interdisciplinary Institute for Personalized Medicine in Brain Disorders, Jinan University, Guangzhou, 510632, China. 2. Center for Translational Systems Biology and Neuroscience, Key Laboratory of Integrative Biomedicine for Brain Diseases, Nanjing University of Chinese Medicine, Nanjing, 210023, China. Funding Support: National Science Foundation of China (81874374, 81803748, 81873096)

ABSTRACT. Hailou Zhang1, Yan Sun1, Wenda Xue2, Gang Chen1#

The rapidly-acting antidepressant is urgently needed for treatment of depression, which may be developed from natural products. Here we found Yueju, a traditional herbal medicine conferring rapid antidepressant-like activity, uniquely up-regulated hippocampal expression of neuropeptide pituitary adenylate cyclase activating polypeptide (PACAP) from a transcriptomic analysis. Blockade of hippocampal PACAP blunted the antidepressant activity of Yueju. High concentration of geniposide (GP) and low concentration of an iridiods compound A (IA) were identified in Yueju. Mixture of them with the dose proportional to Yueju, but not each alone, synergically elicited rapid antidepressant response and up-regulated PACAP expression. High concentration of IA alone was capable to up-regulate PACAP expression and elicit rapid antidepressant response in novelty suppressed feeding, both of which were, however, abrogated when it was mixed with low dose of GP. Optogenetic inactivation of hippocampal PACAP-expressing neurons prevented the antidepressant activity of the synergistic mixture. The synergistic mixture immediate inhibited CaMKII and activated PKA/CREB signaling. In a chronic corticosterone-induced depression model, a single dose synergistic mixture improved performance in depression-related tests and PACAP-related signaling. The present study mechanistically dissected individual compound interaction effects characteristic of traditional medicine, and disclosed a synergism of GP and IA in rapid antidepressant response via a novel mechanism of promoting hippocampal PACAP signaling.

1 Interdisciplinary Institute for Personalized Medicine in Brain Disorders & School of Chinese Medicine, Jinan University, Guangzhou, 510632, China. 2 Center for Translational Systems Biology and Neuroscience, Key Laboratory of Integrative Biomedicine for Brain Diseases, Nanjing University of Chinese Medicine, Nanjing, 210023, China. Funding Support: National Science Foundation of China (81673625, 81803748), the Priority Academic Program Development of Jiangsu Higher Education Institutions (PAPD)

ABSTRACT. Eva Sheardown1, Jose Vicente Torres-Perez1, Sofia Anagianni1, Scott E. Fraser2, Giorgio Vallortigara3, Brian Butterworth4, Maria Elena Miletto-Petrazzini5, Caroline H. Brennan1.

Non-symbolic number cognition based on an approximate sense of magnitude has been documented in a variety of vertebrate species. However, little is known of its neural and molecular bases, especially in developmental and behavioral genetic model species, such as zebrafish. In our experiments, we first examined the ontogeny of numerosity discrimination using a group size preference assay. Fish showed group size preference from 26 days post fertilization (dpf) and from 27 dpf fish reliably chose the larger group when presented with discrimination ratios from 1:8 to 2:3. When the ratio between the number of conspecifics in each group was maintained at 1:2, fish could discriminate between 1 vs. 2 individuals and 3 vs. 6, but not when given a choice between 2 vs. 4 individuals. These findings suggest numerosity processing is the result of an interplay between attentional, cognitive and memory-related mechanisms that orchestrate numerical competence both in humans and animals. To explore the genetics of numerosity cognition, we generated CRISPR loss of function lines in genes associated with poor number cognition in humans; Cytoplasmic FMR1-Interacting Protein (CYFIP) 1 and 2 (Chen et al, 2017). Both CYFIP 1 and 2 mutants have significantly reduced performance of 5 v 2, however, they successfully perform 4 v s 2. This suggests the CYFIP gene plays a role in the abilities and processing of numerical information in zebrafish, further supporting their role human number cognition.

1 School of Biological and Chemical Science, Queen Mary University of London, Mile end road, London, England, E1 4NS. 2 Michelson Center for Convergent Bioscience, University of Southern California, Los Angeles, USA. 3 Center for Mind/Brain Sciences, University of Trento, Rovereto, Italy. 4 UCL Institute of Cognitive Neuroscience, 17 Queen Square, London WC1N 3AZ, UK. 5 Department of Biomedical Sciences, University of Padova, 35131 Padova, Italy.

Funding support: This project has received funding from a Human Frontiers Research Grant to CHB, SEF and GV (HFSP Research Grant RGP0008/2017), from the Leverhulme Trust to CHB, BB and GV (RPG-2016-143), from STARS@UNIPD-2019 (MetaZeb) and Marie Skłodowska-Curie Individual Fellowship (750200) from the European Union’s Horizon 2020 to MEMP, and from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (grant agreement No 833504-SPANUMBRA) to GV.

ABSTRACT. Aleksandra M. Mech1, Saeedeh Husseinian1, Munise Merteroglu2, William Havelange1, Adele Leggieri1, Elisabeth M. Busch-Nentwich2, Caroline Brennan1 

Addiction, including nicotine addiction, is one of the major mental health disorders and a leading cause of death in the world. Previous studies have shown the relevance of genetic factors responsible for a progression to abusive usage, with heritability for smoking estimated to stand at 0.5. Increased understanding of the genetics of smoking is necessary to identify novel drug targets and improve treatment. Here, we used a novel self-administration assay for juvenile fish to screen ENU-mutagenized zebrafish lines for nicotine seeking. The assay consists of 3 asymmetrically connected chambers with nicotine being administered to one of the chambers by diffusion from a point source thereby setting up a concentration gradient across the 3 chambers. Increased time spent in proximity to the nicotine source is taken as evidence of nicotine seeking behavior. We screened 54 families covering 3318 dominant and 1037 recessive alleles for nicotine seeking. Wild-type fish showed limited tendency to approach or avoid the nicotine source. However, 10 families of ENU mutagenized fish showed preference for, or aversion to, the nicotine chamber. Two of these families are predicted to house a dominant mutation affecting the behavior and 8 recessive mutations. So far, we have shown the heritability of the observed phenotype for two of the lines. Future work will assess the heritability for the remaining families and identify the pathways affected.

1School of Biological and Chemical Science, Queen Mary University of London; 2Cambridge Institute of Therapeutic Immunology & Infectious Disease, University of Cambridge

Funding support: NIH R01 grant number U01 DA044400-01 to CHB and EMB

ABSTRACT. Ana Filošević Vujnović1, Milan Petrović2, Ana Meštrović2,3, Rozi Andretić Waldowski1

Drug-dependence is a multifactorial biological and behavioral disorder, commonly studied using simple behavioral response in isolated individuals. Scoring of drug-induced behaviors has been technologically challenging, and knowledge about types and dynamics of social interaction is limited. To investigate group social behavior in Drosophila we used network analysis and deep learning methods, and to validate our approach we compared results with the social behavior of cocaine exposed flies. Groups of 30 adult male wild type flies were kept for 24 hours on molasses food without (CTRL) or with 0.5 mg/mL of cocaine (COC). From 10 minutes video recording we calculated Social Interaction Networks (SINs). CTRL group had higher amount of single pair interactions. We propose that information spreads faster between flies in the CTRL group, supported by the shorter duration of interactions between flies in the CTRL group. Number of communities in CTRL and COC networks does not differ, however CTRL networks have denser connections within the community, while COC networks have more interconnected communities. By applying deep learning analysis, we were able to extract set of classifiers characteristic for CTRL and COC individuals and distinguish individuals from CTRL and COC videos with 90% precision. Our approach can be used useful tool in the study of social behavior of drug treated flies and can expand our knowledge about the rich behavioral repertoire of Drosophila. The results we have obtained will be used for the future studies of sensory cues that are important in social interaction and are modulated by COC administration.

1University of Rijeka, Department of Biotechnology, Rijeka, Croatia, 2University of Rijeka, Department of Informatics, Rijeka, Croatia, 3Center for Artificial Intelligence and Cybersecurity, University of Rijeka, Rijeka, Croatia Funding support: Croatian Science Foundation (HRRZ) project number 2794 and University of Rijeka foundation project uniri-mladi-intpo-20-38.

ABSTRACT. Elisha Wachman, MD1

Rates of Neonatal Opioid Withdrawal Syndrome (NOWS) have increased significantly over the past decade. Approximately 30-80% of affected infants receive pharmacologic treatment with average hospitalizations of 2-3 weeks. The mainstreams of treatment have shifted towards non-pharmacologic interventions, with the use of less medication in current treatment protocols. NOWS remains a highly variable condition that is poorly understood with multiple clinical contributors to incidence and severity. However, clinical variables alone cannot accurately predict the need for pharmacologic treatment. Genetic and epigenetic factors have been identified that could help us to better understand NOWS variability. Small studies to date have identified single nucleotide polymorphisms (SNPs) in opioid receptor and stress response genes that are associated with differences in NOWS outcomes. In addition, differences in DNA methylation were identified within the mu opioid receptor gene (OPRM1) in association with NOWS outcomes. DNA methylation patterns within the placenta of opioid-exposed mothers have also been explored. However, studies to date have been limited by small sample size, lack of replication, and unclear clinical application of the findings. There remains an important role for the study of genetic and epigenetic variation in NOWS. Understanding genetic variation may help to individualize pharmacologic treatment regimens, particularly pharmacogenomic variants. The examination of various maternal treatments for opioid use disorder and the impact on epigenetic profiles in the offspring is also of interest. Lastly, the study of transgenerational epigenetic modification will help us to understand how in-utero opioid exposure can alter responses to opioid medications and risk for addiction in adulthood.

Affiliations: 1Department of Pediatrics, Boston Medical Center, Boston MA, US Funding Support: NICHD R01 HD96798; NIDA Clinical Trials Network UG1DA013732

ABSTRACT. Sex-specific Reward Modulation and Inflammatory Impact of Prenatal Opioid Exposure on the Developing Brain Elizabeth Yen1,2, Tomoko Kaneko-Tarui2, Neel Madan1, Samuel Carpenter3, Alice Graham3, Tomo Tarui1,2, Jonathan Davis1, Jill Maron1,2

1 Department of Pediatrics, Tufts University School of Medicine, Tufts Children’s Hospital, Boston, USA 2 Mother Infant Research Institute, Tufts Medical Center, Boston, USA 3 Department of Psychiatry, Oregon and Health Science University, Portland, USA

Opioid-exposed males are at risk of developing severe withdrawal called neonatal abstinence syndrome (NAS) and require pharmacotherapy (NAS-Tx). The underlying mechanism for this sex-specific risk is unknown. Our laboratory showed that males with NAS-Tx had significantly higher expression of DRD2 (key reward gene) than females, evidence that heightened reward signaling may play a sex-specific role in the severity of NAS. Emerging animal data show that inflammation may modulate the reward property of opioids. Opioid binding to TLR4 on glial cells creates an inflammatory cascade that reinforces its reward/addictive properties with deleterious effects on cognition. Using saliva and brain MRI we aim to understand the potential sex-specific impact of prenatal opioids on pro-inflammatory pathways and the developing brain. Saliva samples collected within 48 hours of birth from 16 neonates with NAS and 16 sex- and age-matched nonexposed controls underwent transcriptomic analyses of IL1B, IL6, TNFα, CXCL1, MCP1 IL10, and DRD2. Compared to controls, neonates with NAS had a 3-fold expression of IL6 and MCP1, with even higher expression (5-fold) in NAS-Tx (p≤0.05). Females with NAS-Tx had a 4-fold expression of IL1B, IL6, MCP1, and downregulation of IL10 than males (p≤0.05); expression of IL6 and MCP1 correlated with DRD2 (r=0.99, p<0.05). Structural MRI showed white matter hyperintensity in four of five females with NAS. All controls had normal MRIs. Functional MRI is ongoing. Prenatal opioids modulate inflammation and reward signaling in a sex-specific manner. Whether prenatal opioids contribute to the white matter changes on the developing brain is subject to further studies.

Funded by: Natalie V. Zucker Research Center for Women’s Scholars Grant, K12 BIRCWH Grant (5K12HD092535-04), Charles H. Hood Foundation Child Health Research A

ABSTRACT. Julie A. Blendy1 , Amelia Dunn1, Shivon Robinson1,2, Crystal Lemchi1, Juliet Mengaziol1, Daniele Mattei3, Michelle Ehrlich3

Opioid use among pregnant women is a growing public health concern in the United States. Infants exposed to opioids in utero are at high risk of exhibiting Neonatal Opioid Withdrawal Syndrome (NOWS). We have developed a mouse model of 3-trimester opioid exposure [gestation to postnatal day 14 (PND 14)] and withdrawal and found that neonatal morphine exposure blunts weight gain, and alters the time to reach developmental milestones. Morphine treated animals undergoing spontaneous somatic withdrawal vocalize significantly more than saline-treated and show increased thermal sensitivity. Changes in microglia activation are also observed and correlated with differential regulation of a variety of cytokines and immune factors. Further, the Oprm1 A118G SNP appears to have a protective effect on these outcomes. To examine if up-regulation of these immune genes persisted into adulthood, and/or were further regulated by opioid exposure in adulthood, mice were allowed to grow to adulthood (PND 84) and were re-exposed to chronic morphine or saline. Of interest, cytokines that were upregulated on PND 15 were significantly downregulated in mice exposed to morphine in utero and during adulthood. Bulk RNA sequencing in cortex following either the first two trimesters of opioid exposure (PND1) or just the third trimester of exposure (PND15) indicate that morphine treatment interferes with the expression of genes associated with key neurodevelopmental and energy utilization processes. The long-term effects of chronic morphine treatment during early life are not well-characterized, particularly the susceptibility to drug-abuse in adulthood or alterations in affect. However, we found no major impact of 3-trimester opioid exposure on reward or anxiety-like behavior. We do see alterations in social behavior with males showing reductions and females showing increases in social affiliation. Using morphine as a prototypical opioid, we are now in a position to exploit our model to investigate underlying mechanisms associated with NOWS including inflammatory response and contribution of the Oprm1 A118G SNP.

1Department of Systems Pharmacology and Translational Therapeutics, Perelman school of Medicine, University of Pennsylvania, Philadelphia , PA 19104, 2Department of Psychology, Williams College, Williamstown, Massachusetts01267, 3Department of Neurology, Icahn School of Medicine, Mount Sinai, New York, NY, 10029. Funding Support: R21 DA044017, R01 DA047743, K12 GM081259

ABSTRACT. Kristyn N. Borrelli 1, Emily J. Yao 1, William W. Yen 2, Qiu T. Ruan 1, Julia C. Kelliher 1, Melanie M. Chen 1, Richard K. Babbs 1, Jacob A. Beierle 1, Elisha M. Wachman 3,4, Alberto Cruz-Martin 2, Camron D. Bryant 1

1Laboratory of Addiction Genetics, Department of Pharmacology and Experimental Therapeutics and Psychiatry, Boston University School of Medicine; 2Department of Biology and Pharmacology, Boston University; 3Department of Pediatrics, Boston Medical Center; 4Grayken Center for Addiction Medicine, Boston Medical Center The Opioid Use Disorder epidemic has led to higher incidence of Neonatal Opioid Withdrawal Syndrome (NOWS). The neurobiological basis of NOWS is largely unknown, but mouse models will help facilitate mechanistic discovery. We aimed to induce repeated cycles of spontaneous opioid withdrawal during a sensitive period of neurodevelopment to understand both short- and long-term behavioral and neurodevelopmental implications of perinatal opioid exposure. We treated neonatal outbred Cartworth Farms White (CFW) mice (Swiss Webster) with morphine sulfate (MOR; 15.0 mg/kg, s.c.) once or twice daily from postnatal day 1 (P1) to P14, the approximate third trimester-equivalent of human gestation. Brainstem (containing pons and medulla) was collected on P15 and processed for transcriptome analysis via mRNA sequencing (RNA-seq). In a separate cohort, adolescent testing was performed from ~P25-36. MOR treatment resulted in weight deficits (P2- 14) that were sustained at P21 and P50. MOR also induced a delayed self-righting latency (P4, P7) and increased ultrasonic vocalizations (USVs; P7, P14). Thermal nociception via hot plate and tail withdrawal assays indicated thermal hyperalgesia in morphine mice (P7, P14). MOR-treated mice also exhibited anxiety-like behavior at P21 (open field). Brainstem transcriptome pathway analysis indicated opposing effects on ribosomal and mitochondrial gene expression by sex, as there was downregulation of genes within these networks in males and upregulation in females, potentially indicating sex-dependent modulation of metabolic function in response to perinatal MOR. During adolescence, MOR treatment was linked to decreased spatial memory performance, reduced anxiety-like behaviors, and increased locomotor activity following treatment with 2.0 mg/kg methamphetamine.

ABSTRACT. Lucy Hall2,4, Kyle T. Brown1,2, Daniel Foster3, Winona Booher2,4, Laura Saba3, Ryan K. Bachtell1,2, Marissa A. Ehringer2,4,

To identify the genes and pathways involved in opioid use disorder, we utilized a longitudinal behavioral paradigm in male and female SHR/Ola and ACI inbred rat strains prior to performing RNA sequencing. Several phenotypes were measured including tests of analgesia, oxycodone intake, tolerance, and withdrawal. SHR/Ola rats were resistant to oxycodone-induced analgesia and showed minimal tolerance after chronic oxycodone self-administration. In contrast, ACI rats displayed an initial robust analgesic response that diminished after chronic oxycodone self-administration. Acquisition of oxycodone self-administration and escalation of oxycodone intake was similar across strains. The motivation to self-administer oxycodone was measured in a progressive ratio test conducted before and after escalated oxycodone intake. SHR/Ola rats showed minimal escalation in the motivation to self-administer oxycodone compared with ACI rats. Transcriptome expression differences were analyzed using RNA sequencing of amygdala and prefrontal cortex tissue collected from both strains following oxycodone self-administration. In the amygdala, 147 genes had a significant oxycodone effect and for 81 of these 147, the oxycodone effects differed significantly between strains. In the prefrontal cortex, 518 genes exhibited an oxycodone effect and in 53 of these genes, the effect of oxycodone differed between strains. Comparison of tissues revealed nine genes that had a significant oxycodone effect in both the prefrontal cortex and amygdala. Pathway-based analyses suggest genes involved in inflammatory response, neural development, and synaptic plasticity show oxycodone-related differences. These data demonstrate that genetics can influence both molecular responses to oxycodone exposure and behavioral responses in this oxycodone consumption paradigm.

1Department of Psychology and Neuroscience University of Colorado Boulder; 2Institute for Behavioral Genetics, University of Colorado Boulder; 3Department of Pharmaceutical Sciences, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of Colorado Anschutz Medical Campus; 4Department of Integrative Physiology, University of Colorado Boulder Funding Support: NIDA U01 DA051937 and NIDA P30 DA044223.

ABSTRACT. Arojit Mitra, Kyungin Kim, Sean P. Deats, Zhong-Wei Zhang, Vivek Kumar. The Jackson Laboratory, Bar Harbor, Maine.

Cytoplasmic FMR1 Interacting Protein-2 (Cyfip2) gene is a key regulator of acute and chronic exposure to psychostimulants. A non-synonymous point mutation [serine (S) – 968 – phenylalanine (F)] in C57BL/6NJ substrain dramatically affects cocaine-induced acute and sensitized responses. To establish causation, we created two new mouse models where we either introduced (S968F) Cyfip2-mutation in the C57BL/6J or corrected it (F968S) in C57BL/6NJ sub-strains using CRISPR/Cas9. Leveraging these models, we causally linked the Cyfip2 mutation with cocaine-induced behavioral outcomes such as acute and sensitized locomotor responses, self-administration, and conditioned place preference, in a background independent manner. For mechanistic insight, a comprehensive electrophysiological investigation was carried out on medium spiny neurons (MSN) of accumbens shell region. Compelling evidences demonstrate Cyfip2 S968F mutation leads to changes in intrinsic and synaptic properties of MSN, in a drug-naïve state, thereby regulating the function of the mesolimbic circuitry that controls cocaine responses. In conclusion, Cyfip2-regulated functional state of MSN provides rationale and direction for further exploration of its role in substance-use disorder and other reward-related maladaptive behaviors.

ABSTRACT. It is a great honor to receive the 2020 IBANGS Distinguished Investigator Award. IBANGS has been central to my development as a scientist, providing me with a sense of community and encouragement in a career that can sometimes be isolating and discouraging. I am also grateful for the many ways in which IBANGS has helped current and former members of my lab to develop their own careers. I will organize my talk by highlighting my 20 publications in the society’s journal, Genes, Brain and Behavior, the first in 2003 and the most recent on April 23rd of this year. I will use these publications to describe multiple projects in my lab, emphasizing the science but also the people who did the science, many of whom also have close connections to IBANGS. This journey will start with postdoctoral work with Dr. Tamara Phillips (Past President and past recipient of this award) on allopregnanolone and a subsequent postdoc with Dr. Conrad Gilliam where I explored the genetics of Autism and fear conditioning. I will describe some of the postdoctoral work of Dr. Camron Bryant (President-elect of IBANGS), who was a postdoc in my lab, on the genetics of methamphetamine sensitivity. I will also review the work of Dr. Clarissa Parker (currently the Secretary of IBANGS), which used advanced intercross lines to explore the genetics of fear and anxiety-related traits in mice and describe how that served as a foundation for some of our future work together and ongoing work in my lab. I will describe early collaborative work with Dr. Harriet de Wit on human genetic studies of the sensitivity to amphetamine and how that was impetus for ongoing collaborative work with 23andMe. I will then highlight several early publications in which my lab began to explore the use of rats rather than mice for genetic studies, which was the basis for what is now the major focus on my lab. Finally, I will discuss my longstanding interest in techniques to integrate ongoing genetic studies of similar traits in humans and rodents.

ABSTRACT. HB Lee1, R Modhurima1, EM Hall1, AN Sigafoos1, AA Heeren1, GE Boyum1, and KJ Clark1,2,3

The hypothalamic-pituitary-adrenal (HPA) axis is the central pathway that leads to glucocorticoid secretion (e.g. cortisol) from the adrenal gland. Cortisol interacts with corticosteroid receptors (e.g. glucocorticoid, mineralocorticoid receptor) to modulate the stress response. We previously reported that abrupt light changes (e.g. dark acclimation followed by 1-min white light exposure and back to darkness) evokes increased locomotion in larval zebrafish during the post-light exposure period. The locomotion was mc2r (adrenocorticotropic hormone receptor) and nr3c1 (glucocorticoid receptor) dependent. However, when we increased the light exposure to 2, 4, 6, and 7.5 min, mc2r and nr3c1 homozygous mutants produced increasing locomotion in light-dose dependent manner with a fully comparable response to WT after 7.5-min light exposure. We tested other genes that interact with HPA signaling. Loss of fkbp5 gene, a glucocorticoid receptor chaperone, shows increased locomotion whereas potential negative regulators of nr3c1, arhgap35a and arhgap35b, do not modify the locomotor response. gabbr2 (enriched in the retinal cells in zebrafish) homozygous mutants showed decreased locomotion even after 7.5-min light exposure. Our findings imply that increased locomotion after 7.5-min white light exposure likely involves at least a second non-HPA signaling pathway. Vision seems to be involved (gabbr2). Glucocorticoid receptor signaling can impact this movement (fkbp5), yet GR is not required (nr3c1 knockouts). Even central HPA axis signaling to produce cortisol is not required (mc2r knockouts). Given that 7.5-min dark-light repeat experiments in zebrafish have been interpreted as producing stress-like or anxiety-like phenotypes, the field will need to proceed with caution when interpreting these responses.

1Biochemistry and Molecular Biology, 2Center for Individualized Medicine, Mayo Clinic, Rochester, MN, 3Neuroscience, Mayo Clinic Graduate School of Biomedical Sciences, Rochester, MN Funding Support: GM134732 R01, National Institute of General Medical Sciences, USA

ABSTRACT. GJ Preston 1, T Kozicz 1

The etiology of psychiatric disorders is complex and poorly understood. Mitochondrial metabolic dysfunction has been strongly implicated in vulnerability to several psychopathologies, including posttraumatic stress disorder (PTSD). We recently identified both brain mitochondrial energy metabolism and the abundance of circulating acetylcarnitine as highly predictive of PTSD-like behavior in a cohort of male mice following exposure to a recently-developed paradigm for the induction of PTSD-like behavior. We therefore hypothesized that supplementation with the antidepressant L-acetylcarnitine (LAC) would mitigate PTSD-like behavior in male mice following exposure to trauma. We exposed 96 C57BL/6J male mice to a PTSD-induction paradigm comprised of two decontextualized sessions of inescapable electric foot shock. Immediately following induction, 48 animals were supplemented with ~100mg/kg/day LAC (0.06% in drinking water ad libitum). All animals were then assayed for light/dark transfer, marble burying, acoustic startle response, and light phase activity, in order to identify PTSD-like and resilient animals. Animals were sacrificed and metabolomic analysis for mitochondrial organic acids, acylcarnitines, and amino acids was performed in circulating plasma. PTSD-like animals supplemented with LAC displayed significantly reduced severity of PTSD-like behavior relative to those supplemented with vehicle alone. Supplementation with LAC also significantly mitigated the corticosterone response to restraint stress in PTSD-like animals. We also observed evidence of significant multisystem mitochondrial stress in both PTSD-like and resilient animals following exposure to the PTSD-induction paradigm, which was significantly mitigated by LAC-supplementation. These data provide valuable evidence on the mechanisms of an emerging antidepressant therapy as a potential intervention in PTSD. 1 Department of Clinical Genomics

ABSTRACT. Antonios M. Diab1, Michael Wigerius1, Dylan P. Quinn1, Jiansong Qi1, Ibrahim Shahin1, Julia Paffile1, Barbara Karten2, Stefan R. Krueger3, and James P. Fawcett1,4

Memory formation and maintenance is a dynamic process involving the modulation of the actin cytoskeleton within the synapse. Understanding the signaling pathways that contribute to this modulation is important for our understanding of synapse formation and function, and in learning and memory. Here, we assess the role of an actin regulator, non-catalytic region of tyrosine kinase adaptor protein 1 (NCK1), in the hippocampus and on behaviour. We report that male mice lacking NCK1 have impairments in short-term memory in a social recognition task, in working memory in a Y-maze, and in spatial learning in the Morris water maze. We find that NCK1 is expressed in post-mitotic neurons but is dispensable for neuronal proliferation and migration in the developing hippocampus. Morphologically, we find that NCK1 is not necessary for overall neuronal dendrite development. However, NCK1-deficient neurons have lower dendritic spine and synapse densities in vitro and in vivo. EM studies reveal that mice lacking NCK1 show an increase in PSD volume and thickness in the CA1 region. Functionally, using FRAP and actin incorporation assays, we find that NCK1 influences the rate of actin turnover in dendritic spines. Together, our study implicates NCK1 as an important molecule in the stabilization of actin dynamics and functions in the formation of dendritic spines, and in hippocampal dependent memory.

1Department of Pharmacology, 2Department of Biochemistry and Molecular Biology, 3Department of Physiology and Biophysics, 4Department of Surgery, Faculty of Medicine, Dalhousie University, Halifax, NS, Canada Funding Support: Canadian Institutes of Health Research (MOP 84366, 79413 and PJT 159738)