Adele Leggieri1 , Judit García-González2 , Saeedeh Hosseinian1 , Peter Ashdown1 , Sofia Anagianni1 , Xian Wang1 , William Havelange1 , Noèlia Fernàndez-Castillo3,4,5,6 , Bru Cormand3,4,5,6 and Caroline H. Brennan1

RBFOX1 regulates transcriptional networks linked to synaptic transmission and neurodevelopment. Mutations in the RBFOX1 gene are associated with psychiatric disorders but how RBFOX1 influences psychiatric disorder vulnerability remains unclear. Recent studies showed that RBFOX1 mediates the alternative splicing of PAC1, a critical HPA axis activator. Further, RBFOX1 dysfunction is linked to dysregulation of BDNF/TrkB, a pathway promoting neuroplasticity, neuronal survival, and stress resilience. Hence, RBFOX1 dysfunction may increase psychiatric disorder vulnerability via HPA axis dysregulation, leading to disrupted development and allostatic overload. To test this hypothesis, we generated a zebrafish rbfox1 loss of function (LoF) line and examined behavioural and molecular effects during development. In larvae and adults, rbfox1 LoF resulted in hyperactivity, impulsivity and hyperarousal, and alterations in proliferation, fertility and survival, traits associated with allostatic overload. In larvae, rbfox1 LoF disrupted expression of pac1a, bdnf, trkb2, and HPI axis genes. These latter were restored after chronic TrkB agonist/antagonist treatment. In adults, bdnf/trkb2 and HPI axes dysregulation was only seen following acute stress. Our findings revealed a strict interplay between RBFOX1 and BDNF/TrkB in stress resilience and suggest that RBFOX1 LoF predisposes to psychiatric diseases through HPA axis hyperactivation during development, impairing adaptation and heightening vulnerability to allostatic overload.

1 School of Biological and Behavioural Sciences, Queen Mary University of London, Mile End Rd, London, E1 4NS, United Kingdom 2 Department of Genetics and Genomic Sciences, Icahn School of Medicine, Mount Sinai, New York City, NY 10029, USA 3 Departament de Genètica, Microbiologia i Estadística, Facultat de Biologia, Universitat de Barcelona, Barcelona, Catalunya, 08028, Spain 4 Centro de Investigación Biomédica en Red de Enfermedades raras (CIBERER), Spain 5 Institut de Biomedicina de la Universitat de Barcelona, Barcelona, Catalunya, 08028, Spain 6 Institut de recerca Sant Joan de Déu, Espluges de Llobregat, Catalunya, 08950, Spain

Alanna E. Carey, Halley L. Dante, Kevin M. Delgado, Rhea Singh, Jerry L. Chen

Individuals exhibit significant variation in their ability to learn complex tasks. This variation could reflect intrinsic or environmental factors. This project aims to understand the neurobiology of individual heritable differences using rodent models and examine how genetic variation alters gene expression and cellular function that influences individual learning and behavior. Utilizing an automated homecage, goal-directed learning paradigm, we assayed learning in Diversity Outbred (DO) mice (n=244) and groups consisting of the eight founder inbred lines (129S1, NZO, CAST, A/J, WSB, C57, NOD, PWK, n=6 per strain). Learning performance highly varied for DO mice, and differences were observed between inbred lines that grouped strains into three learning variance groups. The low-variance learner strain (NZO) learned the task to expert levels compared to the total inbred founder lines, while low-variance non-learner strains (PWK, NOD) failed to advance through procedural learning. Genetic contributions to learning performance were identified in DO animals through Quantitative Trait Loci analysis (QTL), expression QTL (eQTL), and differential expression of genes (DEG) across the neocortex, hippocampus, and striatum. DEG revealed genes influenced by multiple learning phenotypes, and eQTL analysis aligned with QTL and DEG results. We performed spatial transcriptomics utilizing 10X Xenium, exploring candidate genes’ cellular representation in low-variance founder strains. We found cell-type-specific differences between learner and non-learner strains in oligodendrocytes and cholinergic striatal neurons. These findings offer valuable insights into how genetic variation influences goal-directed learning at the cellular and molecular levels. Moreover, these experiments will lay the foundational work toward understanding heterogeneity in cognitive abilities.

Jacob A Beierle¹, Gautam Sabnis¹, Brian Geuther¹, Elaina Cote¹, Stephanie Puig², and Vivek Kumar¹

Migraine is a chronic neurovascular disorder that affects ~15% of the global population. There is a high need for novel migraine therapeutics, as a large percentage of migraineurs do not respond to existing treatment options. Mouse models provide an opportunity to study the biology of migraine to improve treatment, but migraine intensity is typically quantified through mechanical allodynia, which reduces the complex symptomology of migraine to a single feature and suffers from low face validity. Using ethology to infer migraine intensity is an enticing option but determining behaviors that are associated with migraine and manually scoring them has previously been too laborious to be feasible. In this work I leverage machine vision to empower the quantification of a diverse index of voluntary behaviors in the open field arena and from these features construct a score predicting nitroglycerin evoked migraine in male and female C57BL/6J mice. Using this score, I observe sex differences in the male and female response to nitroglycerin, in agreement with previous work in this model and the human migraine literature. I then use Trpa1 knock out mice to validate the specificity of this model to predict migraine, deconvoluting it from other effects of nitroglycerin administration. In the future the throughput of this approach will provide an efficient way to validate human GWAS candidate genes in single gene knockout mice, to assess the impact of genetic background on migraine intensity, and to screen putative therapeutics.

1. The Jackson Laboratory; 2, UMass Chan Medical School

MS Totten1 , AL Peterson1 , DM Pierce2 and KM Erikson2

High fat diets (HFD) have been linked to gene expression alterations, negative behavior changes, and brain disease. Genes such as alpha-synuclein (SNCA) and amyloid precursor protein (APP) are expressed in the hippocampus and are associated with many behaviors. The aims of this study were to evaluate the impact of a HFD on various behaviors and hippocampal SNCA and APP expression in male and female mice from different strains. We hypothesized that behavior and gene expression would be impacted the most in male mice fed a HFD based on our previous diet studies. Mice from strains C57BL/6J and DBA/2J (n=36 per strain; n=36 per sex) were randomly assigned either a control diet (10% kcal fat) or a HFD (60% kcal fat) for 16 weeks. Behavior was measured using the open field test for anxiety, nestlet shredding for general welfare, and novel object recognition for memory. Male C57BL/6J mice fed a HFD had a 7-fold upregulation of hippocampal SNCA expression (p<0.0001) and a 10-fold upregulation of APP expression (p<0.0001) compared to the control diet group. Furthermore, HFD-fed male C57BL/6J mice showed higher anxiety-like behavior assessed by fecal boli (p=0.021) and 183% less nestlet shredding (p=0.017). We found no significant impact of diet on memory. Overall, the HFD treatment impacted male C57BL/6J mice the most in terms of mRNA expression, anxiety, and general welfare. This study demonstrates important biological sex and genetic factors that should be considered when examining the impact of diet on behavior and the brain.

1 Chemistry, Biochemistry, and Nutrition Program, Salem College, Winston-Salem, NC, USA 2 Department of Nutrition, University of North Carolina Greensboro, Greensboro, NC, USA Funding Support: UNC Greensboro Health and Human Sciences Research Grant and Faculty First Award