Havelange, W. | bioRxiv Science

bioRxiv2024

Disrupting fzd9b in zebrafish recapitulates stress- and anxiety-like behaviours associated with Williams syndrome

Williams syndrome (WS) is a multifaceted developmental disorder characterized by a spectrum of physical and intellectual traits. Individuals with WS exhibit friendly, impulsive, and hyper-social behaviours, often coupled with anxiety. WS is attributed to a microdeletion on chromosome 7q11.23, affecting several genes, including FZD9, which plays an important role in neurodevelopment. Thus, we postulated that disruptions in FZD9 might contribute to the behavioural features of WS including anxiety, and that pharmacological interventions targeting Wnt signalling, particularly the canonical pathway, might hold therapeutic potential for WS and related conditions. To test our hypothesis, we generated two mutant zebrafish lines with fzd9b disruptions. Our behavioural analysis revealed significant differences in stress- and anxiety-related responses at both larval and adult stages. Our attempt to restore stress reactivity by manipulating the Wnt/{beta}-catenin pathway using a GSK-3 inhibitor was unsuccessful. Our qPCR data indicated a compensatory mechanism involving the upregulation of fzd9b, wnt5b, and tafa5l genes, potentially contributing to the observed phenotypes. These findings highlight the role of Fzd9b in modulating anxiety responses in zebrafish, offering potential avenues for novel therapeutics to address the neurological features of WS and related disorders. Summary statementsO_LIWe created mutant zebrafish lines to study stress reactivity and social behaviour, mirroring features found in Williams Syndrome (WS). C_LIO_LIConfirmation of fzd9b disruption revealed altered anxiety responses in larval and adult zebrafish. C_LIO_LIMarginal sociability increase was observed in the heterozygous fish for one of the two lines generated. C_LIO_LIAttempts to restore stress reactivity via the Wnt/{beta}-catenin pathway manipulation were unsuccessful. C_LIO_LIWe have identified compensation mechanisms involving upregulation of wnt5b and tafa5l genes. C_LI

neuroscience↗

bioRxiv2022

Behavioural analysis of loss of function zebrafish supports baz1b as master regulator of domestication

Domestication is associated with both morphological and behavioural phenotypic changes that differentiate domesticated species from their wild counterparts. Some of the traits are those purposely targeted by the selection process, whilst others co-occur as a result of selection. The combination of traits is referred to as the domestication syndrome and their shared characteristics has given rise to the neural crest domestication syndrome (NCDS) hypothesis. According to this hypothesis, the phenotypic changes are a consequence of a selection towards animals with mild underdevelopment of the neural crest. A similar mechanism is suggested to affect some species of "self-domesticated" animals, including humans. Recent research supports a role for BAZ1B, one of the haplo-insufficient genes in Williams syndrome (WS), in the evolution of craniofacial features of modern humans. Interestingly, WS recapitulates some of the traits observed in the domestication syndrome, including hypersociability and reduced facial bones. However, the evidence linking BAZ1B to behavioural phenotypes associated with domestication is presumptive. Here, we use zebrafish as a model to test the hypothesis that baz1b loss-of-function leads to both morphological and behavioural phenotypes associated with the domestication syndrome by influencing the development of the neural crest. Our research provides further evidence supporting the NCDS hypothesis and bazlbs role in this process.

animal behavior and cognition↗