CRISPR/Cas9-Induced Inactivation of the Autism-Risk Gene setd5 Leads to Social Impairments in Zebrafish

Abstract

Haploinsufficiency of the SETD5 gene, encoding a SET domain-containing histone methyltransferase, has been identified as a cause of intellectual disability and Autism Spectrum Disorder (ASD). Recently, the zebrafish has emerged as a valuable model to study neurodevelopmental disorders because of its genetic tractability, robust behavioral traits and amenability to high-throughput drug screening. To model human SETD5 haploinsufficiency, we generated zebrafish setd5 mutants using the CRISPR/Cas9 technology and characterized their morphological, behavioral and molecular phenotypes. According to our observation that setd5 is expressed in adult zebrafish brain, including those areas controlling social behavior, we found that setd5 heterozygous mutants exhibit defective aggregation and coordination abilities required for shoaling interactions, as well as indifference to social stimuli. Interestingly, impairment in social interest is rescued by risperidone, an antipsychotic drug used to treat behavioral traits in ASD individuals. The molecular analysis underscored the downregulation of genes encoding proteins involved in the synaptic structure and function in the adult brain, thus suggesting that brain hypo-connectivity could be responsible for the social impairments of setd5 mutant fishes. The zebrafish setd5 mutants display ASD-like features and are a promising setd5 haploinsufficiency model for drug screening aimed at reversing the behavioral phenotypes.

Shedding a Light on Dark Genes: A Comparative Expression Study of PRR12 Orthologues during Zebrafish Development

“…ISH on frozen tissue sections was performed as described in Gabellini et al [25], with some modifications. Cryosections were thawed and washed in PBT (PBS + 0.5% Triton X-100) and incubated with either 300 ng/mL prr21a-201 or prr12b-201 antisense probes at 65 • C O/N.…”

Assessing Drug Administration Techniques in Zebrafish Models of Neurological Disease

“…ENU (N-ethyl-N-nitrosourea) mutagenesis has been utilized to generate knockdown models of FMR1 [252], resulting in zebrafish with ASD-like behavior [157]. Other monogenic zebrafish models of ASD involve the knockout of arid1b [253], chd8 [254], shank3b [64], mecp2 [255], and setd5 [256], among others. Importantly, the monogenic nature of zebrafish models of ASD does not fully recapitulate the environmental influences or the typically polygenic nature of ASD in humans; however, it can provide a simplistic and targeted approach to studying the effects of different therapeutic modalities in reducing the ASD phenotype under specific conditions.…”

“…Few attempts at rescuing autistic-like phenotypes were performed using compounds administered through simple water immersion. Gabellini et al showed that bath immer-sion with risperidone rescued social interest behaviors in setd5 knockout zebrafish [256]. Rahmati-Holasoo et al found that bath immersion with oxytocin provided neuroprotective effects and improved social behaviors in a valproic acid-induced ASD model of zebrafish larvae [260].…”