Serotonergic innervation of the amygdala is increased in autism spectrum disorder and decreased in Williams syndrome

Metabolomic profiles in serum uncover novel biomarkers in children with Williams-Beuren syndrome

Williams-Beuren syndrome (WBS, OMIM-no.194050) is a rare congenital genetic disorder primarily marked by developmental delays and cardiovascular anomalies, with potential involvement of metabolic dysregulation. Despite this, the metabolic features of WBS have not been extensively studied. Thus, our objective was to examine the serum metabolome profile in children with WBS, elucidating metabolic changes and associated pathways in the disorder. We recruited 25 children with WBS (mean age 5.0 ± 2.6 years, 40% female) from the Children's Hospital affiliated to Zhejiang University between 2020 and 2023. An age and sex matched healthy control group (N = 25) were recruited from the Health Management Center in the same hospital. Clinical information of WBS were extracted from the medical records. Blood samples were obtained for untargeted metabolomics analysis using UPLC-MS/MS. The metabolomic profiles of WBS patients were compared to those of healthy controls to identify metabolites with differential abundance. Enrichment analysis was conducted to identify potentially impacted KEGG pathways. Associations between metabolites and phenotypes were evaluated. Children with WBS exhibited a unique metabolic profile compared to healthy controls, as evidenced by the identification of 465 untargeted metabolites in serum. Of these metabolites, 169 showed differential abundance in WBS children. The top enriched KEGG pathways in WBS children included nicotine addiction, cholesterol metabolism, arginine biosynthesis, retrograde endocannabinoid signaling. Additionally, there were indications of potential metabolic alterations in the L-tryptophan pathway, with a shift from serotonin to L-kynurenine, as well as disruptions in bile acid metabolism. Metabolome data in children with WBS showed neurological and amino acid metabolism changes, indicating multisystem involvement and developmental delay. This data can help monitor and manage the disease, but further studies are needed to understand the underlying mechanisms and consequences.

Autism Spectrum Disorder: Neurodevelopmental Risk Factors, Biological Mechanism, and Precision Therapy

Autism spectrum disorder (ASD) is a heterogeneous, behaviorally defined neurodevelopmental disorder. Over the past two decades, the prevalence of autism spectrum disorders has progressively increased, however, no clear diagnostic markers and specifically targeted medications for autism have emerged. As a result, neurobehavioral abnormalities, neurobiological alterations in ASD, and the development of novel ASD pharmacological therapy necessitate multidisciplinary collaboration. In this review, we discuss the development of multiple animal models of ASD to contribute to the disease mechanisms of ASD, as well as new studies from multiple disciplines to assess the behavioral pathology of ASD. In addition, we summarize and highlight the mechanistic advances regarding gene transcription, RNA and non-coding RNA translation, abnormal synaptic signaling pathways, epigenetic post-translational modifications, brain-gut axis, immune inflammation and neural loop abnormalities in autism to provide a theoretical basis for the next step of precision therapy. Furthermore, we review existing autism therapy tactics and limits and present challenges and opportunities for translating multidisciplinary knowledge of ASD into clinical practice.

Oxytocin receptor activation does not mediate associative fear deficits in a Williams Syndrome model

Williams Syndrome results in distinct behavioral phenotypes, which include learning deficits, anxiety, increased phobias and hypersociability. While the underlying mechanisms driving this subset of phenotypes is unknown, oxytocin (OT) dysregulation is hypothesized to be involved as some studies have shown elevated blood OT and altered OT receptor expression in patients. A "Complete Deletion" (CD) mouse, modeling the hemizygous deletion in Williams Syndrome, recapitulates many of the phenotypes present in humans. These CD mice also exhibit impaired fear responses in the conditioned fear task. Here, we address whether OT dysregulation is responsible for this impaired associative fear memory response. We show direct delivery of an OT receptor antagonist to the central nervous system did not rescue the attenuated contextual or cued fear memory responses in CD mice. Thus, increased OT signaling is not acutely responsible for this phenotype. We also evaluated OT receptor and serotonin transporter availability in regions related to fear learning, memory and sociability using autoradiography in wild type and CD mice. While no differences withstood correction, we identified regions that may warrant further investigation. There was a nonsignificant decrease in OT receptor expression in the lateral septal nucleus and nonsignificant lowered serotonin transporter availability in the striatum and orbitofrontal cortex. Together, these data suggest the fear conditioning anomalies in the Williams Syndrome mouse model are independent of any alterations in the oxytocinergic system caused by deletion of the Williams locus.

Decreased density of cholinergic interneurons in striatal territories in Williams syndrome

Williams syndrome (WS) is a rare neurodevelopmental disorder caused by the hemideletion of approximately 25-28 genes at 7q11.23. Its unusual social and cognitive phenotype is most strikingly characterized by the disinhibition of social behavior, in addition to reduced global IQ, with a relative sparing of language ability. Hypersociality and increased social approach behavior in WS may represent a unique inability to inhibit responses to specific social stimuli, which is likely associated with abnormalities of frontostriatal circuitry. The striatum is characterized by a diversity of interneuron subtypes, including inhibitory parvalbumin-positive interneurons (PV+) and excitatory cholinergic interneurons (Ch+). Animal model research has identified an important role for these specialized cells in regulating social approach behavior. Previous research in humans identified a depletion of interneuron subtypes associated with neuropsychiatric disorders. Here, we examined the density of PV+ and Ch+ interneurons in the striatum of 13 WS and neurotypical (NT) subjects. We found a significant reduction in the density of Ch+ interneurons in the medial caudate nucleus and nucleus accumbens, important regions receiving cortical afferents from the orbitofrontal and ventromedial prefrontal cortex, and circuitry involved in language and reward systems. No significant difference in the distribution of PV+ interneurons was found. The pattern of decreased Ch+ interneuron densities in WS differs from patterns of interneuron depletion found in other disorders.