Social Deficits and Repetitive Behaviors Are Improved by Early Postnatal Low-Dose VPA Intervention in a Novel shank3-Deficient Zebrafish Model

Abstract

Mutations of the SHANK3 gene are found in some autism spectrum disorder (ASD) patients, and animal models harboring SHANK3 mutations exhibit a variety of ASD-like behaviors, presenting a unique opportunity to explore the underlying neuropathological mechanisms and potential pharmacological treatments. The histone deacetylase (HDAC) valproic acid (VPA) has demonstrated neuroprotective and neuroregenerative properties, suggesting possible therapeutic utility for ASD. Therefore, SHANK3-associated ASD-like symptoms present a convenient model to evaluate the potential benefits, therapeutic window, and optimal dose of VPA. We constructed a novel shank3-deficient (shank3ab–/–) zebrafish model through CRISPR/Cas9 editing and conducted comprehensive morphological and neurobehavioral evaluations, including of core ASD-like behaviors, as well as molecular analyses of synaptic proteins expression levels. Furthermore, different VPA doses and treatment durations were examined for effects on ASD-like phenotypes. Compared to wild types (WTs), shank3ab–/– zebrafish exhibited greater developmental mortality, more frequent abnormal tail bending, pervasive developmental delay, impaired social preference, repetitive swimming behaviors, and generally reduced locomotor activity. The expression levels of synaptic proteins were also dramatically reduced in shank3ab–/– zebrafish. These ASD-like behaviors were attenuated by low-dose (5 μM) VPA administered from 4 to 8 days post-fertilization (dpf), and the effects persisted to adulthood. In addition, the observed underexpression of grm5, encoding glutamate metabotropic receptor 5, was significantly improved in VPA-treated shank3ab–/– zebrafish. We report for the first time that low-dose VPA administered after neural tube closure has lasting beneficial effects on the social deficits and repetitive behavioral patterns in shank3-deficient ASD model zebrafish. These findings provide a promising strategy for ASD clinical drug development.

The Potency of Goat Milk in Reducing the Induced Neurotoxic Effects of Valproic Acid in Rat Pups as a Rodent Model of Autism Spectrum Disorder

“…Additionally, the results of the behavior interaction test following the nutritional intervention period revealed a significantly better outcome in the GM treatment group for the autistic rodent model compared to the GM treatment group for controls, as well as a marginally better result in the GM treatment group compared to the CM treatment group (Figure 1). This can be explained by the work of [32,33], in which it was shown that the consumption of goat's milk increased dopamine, oxytocin, serotonin, synaptophysin, and α-MSH, which are neurotransmitters and neuropeptides related to ASD, suggesting a potential neuroprotective effect in brain functions, which could enhance social interaction behavior [34][35][36][37].…”

“…and Lactobacillus spp. as probiotics and a decreased abundance of Clostridium perfringens as bacterial species known to be dramatically altered in autistic patients and rodent models [37,[53][54][55].…”

Neuropathological insights from SHANK3 mutant animal models

“…The adult brains of shank3b deficient zebrafish showed significantly reduced levels of both postsynaptic homer1 and presynaptic synaptophysin. These reductions were accompanied by a decrease in locomotor activity, impaired social interaction, and significant repetitive swimming behaviors [36] . Another shank3b mutant zebrafish model also exhibited reductions in synaptic proteins and locomotor activity [37] .…”

Early 7,8-Dihydroxyflavone Administration Ameliorates Synaptic and Behavioral Deficits in the Young FXS Animal Model by Acting on BDNF-TrkB Pathway

“…Several previously published studies support that applying the intervention strategies in the early developmental stages is critical to ameliorate pathological phenotypes of neurodevelopmental disorders [20][21][22]. Early intervention strategies during critical developmental periods exhibit successful improvement in ASD before major symptoms develop [23][24][25]20]. For example, early inhibition of group1 mGlu signaling at development stage, but not in adulthood, could rescue dendritic spine abnormalities in Fmr1 KO mice [26].…”

“…For example, early inhibition of group1 mGlu signaling at development stage, but not in adulthood, could rescue dendritic spine abnormalities in Fmr1 KO mice [26]. Early postnatal low-dose VPA treatment improve ASD-like behaviors associated with sustained rescue of repetitive behavior and social de cits in shank3ab KO zebra sh model [25]. Administration with lovastatin during the early age of Fmr1 KO rats was able to correct associative learning de cits and also has lasting bene cial effects [23].…”