Signalling pathways in autism spectrum disorder: mechanisms and therapeutic implications

Autism spectrum disorder: difficulties in diagnosis and microRNA biomarkers

We performed a PubMed search for microRNAs in autism spectrum disorder that could serve as diagnostic biomarkers in patients and selected 17 articles published from January 2008 to December 2023, of which 4 studies were performed with whole blood, 4 with blood plasma, 5 with blood serum, 1 with serum neural cell adhesion molecule L1-captured extracellular vesicles, 1 with blood cells, and 2 with peripheral blood mononuclear cells. Most of the studies involved children and the study cohorts were largely males. Many of the studies had performed microRNA sequencing or quantitative polymerase chain reaction assays to measure microRNA expression. Only five studies had used real-time polymerase chain reaction assay to validate microRNA expression in autism spectrum disorder subjects compared to controls. The microRNAs that were validated in these studies may be considered as potential candidate biomarkers for autism spectrum disorder and include miR-500a-5p, -197-5p, -424-5p, -664a-3p, -365a-3p, -619-5p, -664a-3p, -3135a, -328-3p, and -500a-5p in blood plasma and miR-151a-3p, -181b-5p, -320a, -328, -433, -489, -572, -663a, -101-3p, -106b-5p, -19b-3p, -195-5p, and -130a-3p in blood serum of children, and miR-15b-5p and -6126 in whole blood of adults. Several important limitations were identified in the studies reviewed, and need to be taken into account in future studies. Further studies are warranted with children and adults having different levels of autism spectrum disorder severity and consideration should be given to using animal models of autism spectrum disorder to investigate the effects of suppressing or overexpressing specific microRNAs as a novel therapy.

Behavioral and transcriptomic effects of a novel cannabinoid on a rat valproic acid model of autism

Autism spectrum disorder (ASD) is a complex neurodevelopmental condition characterized by impaired social communication, restricted interests, repetitive behavior and irritability. Exposure to valproic acid (VPA) during pregnancy has been shown to increase the risk of autism in children and has led to the development of the in-utero VPA rat model that elicits neurodevelopmental autistic-like features. Offspring exhibit behavioral and neurobiological alterations modelling ASD symptoms. We performed a behavioral and molecular assessment in a rat in-utero VPA model treated with a novel botanical cannabinoid, JZP541. Male offspring from dams treated with VPA were tested acutely and sub-chronically with JZP541 (10, 30, or 100 mg/kg, intraperitoneally). A behavioral testing battery was performed, and brain frontal cortex and hippocampus used for RNA sequencing. In utero exposure to VPA resulted in progeny showing behavioral phenotypes characteristic of ASD. JZP541 attenuated these deficits in social, stereotypic, hyperactivity and irritability behavior in a dose-dependent fashion. VPA exposure was associated with a substantial transcriptional dysregulation impacting multiple key biological processes in a tissue-dependent manner. The expression profiles were integrated with publicly available datasets of autism-associated genes to support the validity of the model used and to focus on the effects of treatment on known autism-relevant transcriptional targets. This approach indicated a strong and dose-dependent reduction of the autism-associated gene expression signature in brain samples from animals dosed with JZP541. Our findings demonstrate JZP541 was able to ameliorate ASD associated behavioral deficits, and this was supported by improvements in putative transcriptional biomarkers of ASD.

Postnatal propionic acid exposure disrupts hippocampal agmatine homeostasis leading to social deficits and cognitive impairment in autism spectrum disorder-like phenotype in rats

Autism Spectrum Disorder (ASD) is a complex neurodevelopmental condition characterized by a range of symptoms including impaired social interaction and cognitive deficits. Although the exact pathogenesis of ASD is not well established, recent clinical findings suggest a decline in levels of biogenic amine agmatine in autistic patients. The present study was designed to investigate the impact of postnatal propionic acid (PPA) exposure on hippocampal agmatine homeostasis in male rat pups and to explore a new therapeutic intervention for ASD using agmatine as a biological target. PPA is commonly used in experimental models of ASD due to its ability to induce social deficits, cognitive impairments, and stereotyped behaviors, which closely resemble key characteristics of ASD. Male rat pups were administered with PPA via the intrahippocampal route bilaterally (25 μg/0.25 μl per side) on PND-21 to simulate the ASD phenotype, and its subsequent effect on the endogenous agmatinergic system. The influence of agmatine treatment and its endogenous modulation on ASD-like phenotypes was also investigated. Behavioral assessments revealed that PPA exposure reduced sociability and social preference, caused learning and memory impairment in the Morris water maze, increased anxiety-like behavior in the elevated plus maze, and reduced exploratory behavior in the hole board test. Neurochemical analyses showed a decrease in agmatine concentration and an increase in its degrading enzyme agmatinase in the hippocampus. PPA treatment altered the content of GABA, glutamate, TNF-α, IL-6, BDNF, and also resulted in increased astrogliosis and neurotoxicity within the hippocampus. Chronic agmatine treatment and its endogenous modulation ameliorated the behavioral and biochemical disruptions induced by PPA exposure. This study highlights the critical role of hippocampal agmatinergic pathway in the etiopathogenesis of ASD, positioning agmatine as a promising therapeutic target for its treatment.

Neural connections and molecular mechanisms underlying motor skill deficits in genetic models of autism spectrum disorders

Autism spectrum disorders (ASDs) comprise a broad category of neurodevelopmental disorders that include repetitive behaviors and difficulties in social interactions. Notably, individuals with ASDs exhibit significant impairments in motor skills even prior to the manifestation of other core symptoms. These skills are crucial for daily activities, such as communication, imitation, and exploration, and hold significant importance for individuals with ASDs. This review seeks to offer new insights into the understanding of motor skill impairments by delineating the pathological mechanisms underlying motor skill learning impairments associated with gene mutations in Fmr1, Chd8, Shank3, BTBR, 16p11.2, and Mecp2, predominantly drawing from well-characterized genetic mouse model studies and proposing potential targets for future therapeutic interventions. We further discuss the underlying pathogenic abnormalities associated with the development of specific brain regions within the cerebellum and cerebrum, as well as disruptions in the structure and function of critical neuronal connectivity pathways. Additional research utilizing epidemiological data, clinical observations, and animal research methodologies is warranted to enhance our understanding of the effect of motor skill learning on the growth, development, and social integration of children. Ultimately, our review suggests potential targets for future therapeutic interventions.

Evaluation of Erythropoietin and Erythropoietin Receptor Levels in Children with Autistic Spectrum Disorder: Cross-sectional Study

Objective

Autistic spectrum disorders (ASD) are a heterogeneous collection of neurodevelopmental disorders with an unknown etiology. Erythropoietin is a versatile growth factor that plays a crucial role in the nervous system, exhibiting high expression in various regions of the brain, including neurons, glial cells and endothelial cells. Recent animal studies have demonstrated that Epo exerts neuroprotective and neurotrophic effects. The objective of this study was to examine the levels of erythropoietin-(Epo) and its receptor-(EpoR) in children with ASD and to elucidate the potential effects of Epo in the disorder.

Methods

The study involved 50 children diagnosed with ASD based on the 5th Edition of the Diagnostic and Statistical Manual of Mental Disorders criteria, with ASD severity assessed using the Childhood Autism Rating Scale. Additionally, a control group of 50 healthy children was included. Serum samples were collected from both groups, and levels of Epo and its EpoR.

Results

There were no statistically significant differences between the age and sex distributions of the ASD and control groups (p > 0.05). However, analysis of the serum samples revealed a statistically significant reduction in Epo levels in the ASD cohort compared to the control.

Conclusion

The results of our study indicate that Epo may have potential as an adjunctive therapy for children with ASD. The observed decrease in Epo levels and increase in EpoR levels in children with ASD suggest a dysregulation in the Epo-EpoR axis that may contribute to the pathophysiology of ASD. Further research is required to investigate the therapeutic effects of modulating Epo levels in ASD and to elucidate the mechanisms underlying these changes.

Molecular basis of autism spectrum disorders

Autism is a prevalent neurological disorder that affects the development of children worldwide. With the advent of genome wide association studies and whole exome sequencing methods, associated genes and molecular pathways that lead to the development of autism spectrum disorder (ASD) have garnered recent attention. However, the etiology of ASD is still rudimentary and poorly understood. Thus, understanding the specific molecular pathways that contribute to autism aids in its clinical diagnosis, management, and treatment. Currently, the genes involved are expansive and affect many molecular pathways. These include transcriptional and translational regulation, proteostasis, cytoskeletal organization, synaptic development and plasticity, and autophagy. Additionally, there are a multitude of factors involved in ASD pathogenesis, including neuroinflammation, signaling defects, and vitamin deficiencies. This review aims to provide a comprehensive understanding regarding the genes and underlying molecular mechanisms that contribute to ASD and the translational therapies for the management of ASD.

Genomic diversity in functionally relevant genes modifies neurodevelopmental versus neoplastic risks in individuals with germline PTEN variants

Individuals with germline PTEN variants (PHTS) have increased risks of the seemingly disparate phenotypes of cancer and neurodevelopmental disorders (NDD), including autism spectrum disorder (ASD). Etiology of the phenotypic variability remains elusive. Here, we hypothesized that decreased genomic diversity, manifested by increased homozygosity, may be one etiology. Comprehensive analyses of 376 PHTS patients of European ancestry revealed significant enrichment of homozygous common variants in genes involved in inflammatory processes in the PHTS-NDD group and in genes involved in differentiation and chromatin structure regulation in the PHTS-ASD group. Pathway analysis revealed pathways germane to NDD/ASD, including neuroinflammation and synaptogenesis. Collapsing analysis of the homozygous variants identified suggestive modifier NDD/ASD genes. In contrast, we found enrichment of homozygous ultra-rare variants in genes modulating cell death in the PHTS-cancer group. Finally, homozygosity burden as a predictor of ASD versus cancer outcomes in our validated prediction model for NDD/ASD performed favorably.

Calcitriol Modulates Hippocampal Axon Guidance Through Enhanced EfnA4-Mediated PI3K/AKT Signaling in an Autism Mouse Model

AIMS

Autism spectrum disorder (ASD) is a complex neurodevelopmental condition arising from the interplay of genetic predispositions and environmental influences. Recent studies have suggested that vitamin D (VitD) supplementation play a role in reducing the risk of ASD and alleviating some of its core symptoms. However, variations in individual responses to VitD due to biological heterogeneity have led to inconsistent clinical outcomes, and the precise molecular mechanisms through which VitD might exert its effects on ASD remain poorly understood.

METHODS

We investigated the effects of calcitriol, the biologically active form of VitD, on ASD-associated phenotypes in BTBR mice, a well-established autism model. Behavioral assessments were used to evaluate social and repetitive behaviors. Mechanistic insights were obtained through RNA sequencing, immunohistochemistry, biochemical assays, and stripe guidance assays.

RESULTS

Calcitriol supplementation significantly improved autism-like behaviors in BTBR mice, alleviating hippocampal hypoplasia and correcting axon guidance abnormalities. These effects were mediated by modulation of the EfnA4-PI3K signaling pathway in hippocampal neural progenitor cells and other brain regions, highlighting its role in neurodevelopmental processes.

CONCLUSION

Our findings demonstrate that calcitriol targets axon-guidance-related signaling pathways, providing a theoretical framework and potential clinical strategy for targeted ASD interventions.

Enhanced detection of autism spectrum disorder through neuroimaging data using stack classifier ensembled with modified VGG-19

BackgroundAutism spectrum disorder (ASD) is a neurodevelopmental disease marked by a variety of repetitive behaviors and social communication difficulties.PurposeTo develop a generalizable machine learning (ML) classifier that can accurately and effectively predict ASD in children.Material and MethodsThis paper makes use of neuroimaging data from the Autism Brain Imaging Data Exchange (ABIDE I and II) datasets through a combination of structural and functional magnetic resonance imaging data. Several ML models, such as Support Vector Machines (SVM), CatBoost, random forest (RF), and stack classifiers, were tested to demonstrate which model performs the best in ASD classification when used alongside a deep convolutional neural network.ResultsResults showed that stack classifier performed the best among the models, with the highest accuracy of 81.68%, sensitivity of 85.08%, and specificity of 79.13% for ABIDE I, and 81.34%, 83.61%, and 82.21% for ABIDE II, showing its superior ability to identify complex patterns in neuroimaging data. SVM performed poorly across all metrics, showing its limitations in dealing with high-dimensional neuroimaging data.ConclusionThe results show that the application of ML models, especially ensemble approaches like stack classifier, holds significant promise in improving the accuracy with which ASD is detected using neuroimaging and thus shows their potential for use in clinical applications and early intervention strategies.

Deregulated mRNA and microRNA Expression Patterns in the Prefrontal Cortex of the BTBR Mouse Model of Autism

Autism spectrum disorder (ASD) is a neurodevelopmental condition caused by both genetic and environmental factors. Since no single gene variant accounts for more than 1% of the cases, the converging actions of ASD-related genes and other factors, including microRNAs (miRNAs), may contribute to ASD pathogenesis. To date, few studies have simultaneously investigated the mRNA and miRNA profiles in an ASD-relevant model. The BTBR mouse strain displays a range of behaviors with ASD-like features but little is known about the protein-coding and noncoding gene expression landscape that may underlie the ASD-like phenotype. Here we performed parallel mRNA and miRNA profiling using the prefrontal cortex (PFC) of BTBR and C57BL/6 J (B6) mice. This identified 1063 differentially expressed genes and 48 differentially expressed miRNAs. Integration of mRNA and miRNA data identified a strong inverse relationship between upregulated (DEGs) and downregulated miRNAs, and vice versa. Pathway analysis, taking account of the inverse relationship between differentially expressed miRNAs and their target mRNAs highlighted significant shared enrichment in immune signaling, myelination, and neurodevelopmental processes. Notably, miRNA changes were predicted to affect synapse-related functions but we did not find enrichment of protein-coding genes linked to cellular components or biological processes related to synapses in the PFC of BTBR mice, indicating processes may evade miRNA control. In contrast, other miRNAs were predicted to have extensive relationships with DEGs suggesting their role as potential hub coordinators of gene expression. Profiling findings were confirmed via qRT-PCR for representative protein-coding transcripts and miRNAs. Our study underscores the complex interplay between gene expression and miRNA regulation within immune and inflammatory pathways in the BTBR model, offering insights into the neurodevelopmental mechanisms of ASD. These results support the value of the BTBR mouse model and identify strategies that could adjust molecular pathways for therapeutic applications in ASD research.

Multilevel Factors and Indicators of Atypical Neurodevelopment During Early Infancy in Japan: Prospective, Longitudinal, Observational Study

Background

The early identification of developmental concerns requires understanding individual differences that may represent early signs of neurodevelopmental conditions. However, few studies have longitudinally examined how child and maternal factors interact to shape these early developmental characteristics.

Objective

We aim to identify factors from the perinatal to infant periods associated with early developmental characteristics that may precede formal diagnoses and propose a method for evaluating individual differences in neurodevelopmental trajectories.

Methods

A prospective longitudinal observational study of 147 mother-child pairs was conducted from gestation to 12 months post partum. Assessments included prenatal questionnaires and blood collection, cord blood at delivery, and postpartum questionnaires at 1, 6, and 12 months. The Modified Checklist for Autism in Toddlers (M-CHAT) was used to evaluate developmental characteristics that might indicate early signs of atypical neurodevelopment. Polychoric or polyserial correlation coefficients assessed relationships between M-CHAT scores and longitudinal variables. L2-regularized logistic regression and Shapley Additive Explanations predicted M-CHAT scores and determined feature contributions.

Results

Twenty-one factors (4 prenatal, 3 at birth, and 14 postnatal) showed significant associations with M-CHAT scores (adjusted P values<.05). The predictive accuracy for M-CHAT scores demonstrated reasonable predictive accuracy (area under the receiver operating characteristic curve=0.79). Key predictors included infant sleep status after 6 months (nighttime sleep duration, bedtime, and difficulties falling asleep), maternal Kessler Psychological Distress Scale scores, and Mother-to-Infant Bonding Scale scores after late gestation.

Conclusions

Maternal psychological distress, mother-infant bonding, and infant sleep patterns were identified as significant predictors of early developmental characteristics that may indicate emerging developmental concerns. This study advances our understanding of early developmental assessment by providing a novel approach to identifying and evaluating early indicators of atypical neurodevelopment.

Genetic advances in neurodevelopmental disorders

Neurodevelopmental disorders (NDDs) are a group of highly heterogeneous diseases that affect children's social, cognitive, and emotional functioning. The etiology is complicated with genetic factors playing an important role. During the past decade, large-scale whole exome sequencing (WES) and whole genome sequencing (WGS) have vastly advanced the genetic findings of NDDs. Various forms of variants have been reported to contribute to NDDs, such as de novo mutations (DNMs), copy number variations (CNVs), rare inherited variants (RIVs), and common variation. By far, over 200 high-risk NDD genes have been identified, which are involved in biological processes including synaptic function, transcriptional and epigenetic regulation. In addition, monogenic, oligogenic, polygenetic, and omnigenic models have been proposed to explain the genetic architecture of NDDs. However, the majority of NDD patients still do not have a definitive genetic diagnosis. In the future, more types of risk factors, as well as noncoding variants, are await to be identified, and including their interplay mechanisms are key to resolving the etiology and heterogeneity of NDDs.

The epilepsy-autism phenotype associated with developmental and epileptic encephalopathies: New mechanism-based therapeutic options

Epilepsy and autism often co-occur in genetic developmental and epileptic encephalopathies (DEEs), but their underlying neurobiological processes remain poorly understood, complicating treatment. Advances in molecular genetics and understanding the neurodevelopmental pathogenesis of the epilepsy-autism phenotype may lead to mechanism-based treatments for children with DEEs and autism. Several genes, including the newly reported PPFIA3, MYCBP2, DHX9, TMEM63B, and RELN, are linked to various neurodevelopmental and epileptic disorders, intellectual disabilities, and autistic features. These findings underscore the clinical heterogeneity of genetic DEEs and suggest diverse neurobiological mechanisms influenced by genetic, epigenetic, and environmental factors. Mechanisms linking epilepsy and autism include γ-aminobutyric acidergic (GABAergic) signaling dysregulation, synaptic plasticity, disrupted functional connectivity, and neuroinflammatory responses. GABA system abnormalities, critical for inhibitory neurotransmission, contribute to both conditions. Dysregulation of the mechanistic target of rapamycin (mTOR) pathway and neuroinflammation are also pivotal, affecting seizure generation, drug resistance, and neuropsychiatric comorbidities. Abnormal synaptic function and connectivity further underscore the epilepsy-autism phenotype. New treatment options targeting specific mechanisms linked to the epilepsy-autism phenotype are emerging. Genetic variants in potassium channel genes like KCNQ2 and KCNT1 are frequent causes of early onset DEEs. Personalized treatments like retigabine and quinidine have been explored with heterogeneous responses. Efforts are ongoing to develop more effective KCNQ activators and KCNT1 blockers. SCN1A genetic variants, particularly in Dravet syndrome, show potential for treatment of autistic symptoms with low-dose clonazepam, fenfluramine, and cannabidiol, although human trials have yet to consistently replicate animal model successes. Early intervention before the age of 3 years, particularly in SCN1A- and tuberous sclerosis complex-related DEEs, is crucial. Additionally, targeting the mTOR pathway shows promise for seizure control and managing epilepsy-associated comorbidities. Understanding the distinct autism spectrum disorder phenotype in DEEs and implementing early behavioral interventions are essential for improving outcomes. Despite genetic advances, significant challenges persist in diagnosing and treating DEE-associated epilepsy-autism phenotypes. Future clinical trials should adopt precision health approaches to improve neurodevelopmental outcomes.

Lactobacillus paracasei-derived extracellular vesicles reverse molecular and behavioral deficits in mouse models of autism spectrum disorder

Autism spectrum disorder (ASD) is a heterogeneous group of neurodevelopmental disorders characterized by social communication deficits and repetitive behaviors. Although our current understanding the mechanisms underlying ASD is growing, effective treatment options are still underdevelopment. Extracellular vesicles derived from the probiotic Lactobacillus paracasei (LpEV) have shown neuroprotective effects in both in vitro and in vivo models. Here we investigate whether LpEV can alleviate core symptoms in genetic ASD models that exhibit accumulated developmental deficits. Dopamine receptor D2 (Drd2)-knockout (KO) mice exhibit social behavior deficits and excessive grooming, core symptoms of ASD. LpEV treatment significantly improves these autistic-like behaviors in Drd2-KO mice, suggesting that LpEVs can mitigate the persistent dysregulation of signaling pathways in these mice. RNA sequencing followed by Gene Ontology enrichment analysis of LpEV-treated Drd2-KO mice identifies distinct groups of genes altered in the brain of Drd2-KO mice, which were reversed by LpEV treatment. Notably, a high proportion of these genes overlap significantly with known ASD genes in the SFARI database, strengthening the potential of LpEV to target relevant pathways in ASD. Further investigation identifies oxytocin and oxytocin receptor (Oxtr) as potential therapeutic targets. LpEV treatment significantly improves autistic-like behaviors in Oxtr-KO heterozygous mice, adenylyl cyclase-5 KO mice and Shank3-KO mice, suggesting its therapeutic potential to target ASD through broader mechanisms beyond a single gene pathway. These results highlight the therapeutic potential of LpEV in reversing the accumulated dysregulated signaling pathways leading to ASD symptoms and improving autistic-like behaviors.

Psychedelics and Pro-Social Behaviors: A Perspective on Autism Spectrum Disorders

Autism Spectrum Disorders (ASD) are complex neurodevelopmental conditions characterized by deficits in social interaction, communication, and repetitive behaviors. This viewpoint explores the potential mechanisms through which psychedelics such as lysergic acid diethylamide (LSD), psilocybin, and 3,4-methylenedioxymethamphetamine (MDMA) may positively influence pro-social behaviors, focusing on their implications for individuals with ASD.

Molecular mechanisms of GDNF/GFRA1/RET and PI3K/AKT/ERK signaling interplay in neuroprotection: Therapeutic strategies for treating neurological disorders

Neurological disorders, marked by progressive neuronal degeneration, impair essential cognitive functions like memory and motor coordination… This manuscript explores the significant roles of glial cell line-derived neurotrophic factor (GDNF), its co-receptors (GFRA1), and the receptor tyrosine kinase (RET) in mediating neuronal survival and function in various neurodegenerative conditions. The interplay between pivotal signaling pathways-PI3K/AKT and ERK1/2-facilitated by GDNF/GFRA1/RET, is emphasized for its neuroprotective effects. Dysregulation of these pathways is implicated in neurodegenerative and neuropsychiatric processes, with overactivation of GSK3β contributing to neuronal damage and apoptosis. Experimental evidence supports that activation of the RET receptor by GDNF enhances AKT signaling, promoting cell survival by inhibiting apoptotic pathways-therapeutic strategies incorporating GDNF delivery and RET activation present promising neuronal protection and regeneration options. Furthermore, inhibition of GSK3β demonstrates potential in ameliorating tau-related pathologies, while small molecule RET agonists may enhance therapeutic efficacy. This review explores the knowledge of GDNF/GFRA1/RET and PI3K/AKT/ERK1/2 associated signaling cascades, underscoring their significance in neuroprotection and therapeutic targeting to combat neurodegenerative diseases. Emerging approaches such as gene therapy and small-molecule RET agonists may offer novel avenues for treatment, although challenges like targeted delivery across the blood-brain barrier remain pertinent.

Biological subtyping of autism via cross-species fMRI

It is frequently assumed that the phenotypic heterogeneity in autism spectrum disorder reflects underlying pathobiological variation. However, direct evidence in support of this hypothesis is lacking. Here, we leverage cross-species functional neuroimaging to examine whether variability in brain functional connectivity reflects distinct biological mechanisms. We find that fMRI connectivity alterations in 20 distinct mouse models of autism (n=549 individual mice) can be clustered into two prominent hypo- and hyperconnectivity subtypes. We show that these connectivity profiles are linked to distinct signaling pathways, with hypoconnectivity being associated with synaptic dysfunction, and hyperconnectivity reflecting transcriptional and immune-related alterations. Extending these findings to humans, we identify analogous hypo- and hyperconnectivity subtypes in a large, multicenter resting state fMRI dataset of n=940 autistic and n=1036 neurotypical individuals. Remarkably, hypo- and hyperconnectivity autism subtypes are replicable across independent cohorts (accounting for 25.1% of all autism data), exhibit distinct functional network architecture, are behaviorally dissociable, and recapitulate synaptic and immune mechanisms identified in corresponding mouse subtypes. Our cross-species investigation, thus, decodes the heterogeneity of fMRI connectivity in autism into distinct pathway-specific etiologies, offering a new empirical framework for targeted subtyping of autism.

The impact of physical exercise interventions on social, behavioral, and motor skills in children with autism: a systematic review and meta-analysis of randomized controlled trials

Background

Autism Spectrum Disorder (ASD) is a neurodevelopmental disorder characterized by social impairments, sensory processing issues, repetitive behavior patterns, motor abnormalities, and executive function impairments.

Objective

To systematically review and meta-analyze the effects of various exercise modalities on flexibility and cognitive control, social skills, behavioral problems, motor skills, and coordination in children with ASD, providing scientific evidence for clinical practice to guide effective exercise interventions for children with ASD.

Methods

Literature searches were conducted in PubMed, EMbase, Cochrane Library, EBSCOhost, and Web of Science databases, covering the period from database inception to February 15, 2024. Inclusion criteria included studies involving children with ASD, any form of exercise intervention, reporting at least one ASD-related outcome, and designed as randomized controlled trials (RCTs) or quasi-experimental studies. Exclusion criteria included reviews, conference abstracts, commentary articles, and studies lacking sufficient statistical data for meta-analysis. Study quality was assessed using the PEDro scale. Effect sizes were calculated using standardized mean differences (SMD). Heterogeneity was assessed with the I 2 statistic. Multiple subgroup analyses were conducted, and publication bias was evaluated using Begg's Test and Egger's Test.

Results

23 RCTs were included in this study, showing positive effects of exercise interventions in various domains.Upper grade students showed significant improvement in flexibility and cognitive control (SMD = -0.282, p = 0.161). Lower grade children showed the most significant improvement in motor skills and coordination (SMD = 0.475, p = 0.043). Preschool children showed significant enhancement in social skills (SMD = 0.312, p = 0.041). Behavioral problems improved significantly across all age groups (SMD = -0.674, p < 0.001). Martial arts and ball games were particularly effective in enhancing these domains, and appropriate periodic exercise interventions effectively improved various abilities in children with ASD. Results varied across different ages and intervention types.

Conclusion

Exercise interventions significantly improve flexibility, cognitive control, motor skills, coordination, social skills, and behavioral problems in children with ASD. This study supports exercise interventions as an effective method to enhance multiple abilities in children with ASD and emphasizes the importance of designing personalized intervention programs tailored to different ages and needs. Future research should focus on larger sample sizes and long-term follow-ups to confirm the sustainability and generalizability of intervention effects.

Cortex-Specific Tmem169 Deficiency Induces Defects in Cortical Neuron Development and Autism-Like Behaviors in Mice

The development of the nervous system is a complex process, with many challenging scientific questions yet to be resolved. Disruptions in brain development are strongly associated with neurodevelopmental disorders, such as intellectual disability and autism. While the genetic basis of autism is well established, the precise pathological mechanisms remain unclear. Variations on chromosome 2q have been linked to autism, yet the specific genes responsible for the disorder have not been identified. This study investigates the role of the transmembrane protein 169 (TMEM169) gene, located on human chromosome 2q35, which has not been previously characterized. Our findings indicate that Tmem169 is highly expressed in the nervous system, and its deletion in the male mouse dorsal forebrain results in neuronal morphological abnormalities and synaptic dysfunction. Notably, Tmem169-deficient mice, irrespective of sex, display behavioral traits resembling those observed in individuals with autism. These results suggest that Tmem169 interacts with several key neuronal proteins, many of which are implicated in neurodevelopmental diseases. Furthermore, we demonstrate that Tmem169 promotes neuronal process and synapse development through its interaction with Shank3.

Protein arginine methyltransferase 7 linked to schizophrenia through regulation of neural progenitor cell proliferation and differentiation

Genome-wide association studies (GWASs) have identified numerous genomic loci linked to schizophrenia (SCZ), while their pathogenic mechanisms largely remain unclear. This study demonstrated protein arginine methyltransferase 7 (PRMT7) as a key target of SCZ risk SNPs with allele-specific enhancer activity at 16q22.1. Downregulating PRMT7 in neural progenitor cells (NPCs) decreased proliferation, increased neuronal differentiation, and also led to longer neurites in these neurons. Conversely, overexpressing PRMT7 enhanced NPC proliferation and reduced neuronal differentiation. In three-dimensional (3D) cerebral organoids, similar NPC phenotypic changes were noted following PRMT7 depletion. Mechanistically, PRMT7 regulates the expression of genes related to the cell cycle and neuronal functions, such as CDKN2A and SYP, via symmetrical di-methylation at arginine 3 of histone 4 (H4R3me2s) modification in their promoters. Notably, these genes have a stronger association with SCZ compared to other mental disorders. Together, the results of this study reveal that PRMT7 is a functional gene at 16q22.1, contributing to the etiology of SCZ by modulating NPC proliferation and differentiation as an epigenetic regulator.

Available Treatments for Autism Spectrum Disorder: From Old Strategies to New Options

Autism spectrum disorder (ASD) is a condition that is gaining increasing interest in research and clinical fields. Due to the improvement of screening programs and diagnostic procedures, an increasing number of cases are reaching clinical attention. Despite this, the available pharmacological options for treating ASD-related symptoms are still very limited, and while a wide number of studies are focused on children or adolescents, there is a need to increase research about the treatment of ASD in adult subjects. Given this framework, this work aims to review the available literature about pharmacological treatments for ASD, from older strategies to possible new therapeutic targets for this condition, which are often poorly responsive to available resources. The literature, besides confirming the efficacy of the approved drugs for ASD, shows a lack of adequate research for several psychopharmacological treatments despite possible promising results that need to be further investigated.

Effects of gastrointestinal symptoms on the efficacy of washed microbiota transplantation in patients with autism

Objective

Washed microbiota transplantation (WMT) has emerged as a promising therapeutic strategy for autism spectrum disorder (ASD), though the factors that influence its efficacy remain poorly understood. This study explores the impact of gastrointestinal (GI) symptoms on the effectiveness of WMT in ASD.

Methods

Clinical data encompassing ASD symptoms, GI disturbances, and sleep disorders were collected from patients with ASD undergoing WMT. The therapeutic impact of WMT and the contributing factors to its efficacy were assessed.

Results

WMT significantly reduced scores on the Aberrant Behavior Checklist (ABC), Childhood Autism Rating Scale (CARS), and Sleep Disturbance Scale for Children (SDSC), alongside a significant reduction in the incidence of constipation, abnormal stool forms, and diarrhea (all p < 0.05). After six courses of WMT, substantial reductions were observed in ABC, CARS, and SDSC scores, with increased treatment courses correlating with greater improvement (p < 0.05). Multiple linear regression analysis revealed that WMT efficacy was enhanced in patients with pre-existing GI symptoms (diarrhea: β = 0.119, p < 0.001; abnormal stool form: β = 0.201, p < 0.001) and those receiving a higher number of treatment courses (β = 0.116, p < 0.001). Additionally, the analysis indicated that treatment outcomes were more favorable in patients who had not undergone adjunct interventions (β = -0.041, p = 0.002), had a longer disease duration (β = 0.168, p = 0.007), and exhibited more severe disease symptoms (β = 0.125, p < 0.001).

Conclusion

WMT significantly alleviates both ASD and GI symptoms, along with sleep disturbances, in affected individuals. Six treatment courses resulted in notable improvement, with increased course numbers further improving therapeutic outcomes. Furthermore, pre-treatment GI symptoms, such as diarrhea and abnormal stool forms, may influence the effectiveness of WMT. Notably, patients who did not receive additional interventions, had a prolonged disease duration, and presented with more severe symptoms experienced markedly improved treatment responses.

Gangliosides and Cholesterol: Dual Regulators of Neuronal Membrane Framework in Autism Spectrum Disorder

Autism spectrum disorder (ASD) is a neurodevelopmental disorder with heterogeneous clinical presentation. Diagnosing ASD is complex, and the criteria for diagnosis, as well as the term ASD, have changed during the last decades. Diagnosis is made based on observation and accomplishment of specific diagnostic criteria, while a particular biomarker of ASD does not yet exist. However, studies universally report a disequilibrium in membrane lipid content, pointing to a unique neurolipid signature of ASD. This review sheds light on the possible role of cholesterol and gangliosides, complex membrane glycosphingolipids, in the development of ASD. In addition to maintaining membrane integrity, neuronal signaling, and synaptic plasticity, these lipids play a role in neurotransmitter release and calcium signaling. Evidence linking ASD to lipidome changes includes low cholesterol levels, unusual ganglioside levels, and unique metabolic profiles. ASD symptoms may be mitigated with therapeutic interventions targeting the lipid composition of membranes. However, restoring membrane equilibrium in the central nervous system remains a challenge. This review underscores the need for comprehensive research into lipid metabolism to uncover practical insights into ASD etiology and treatment as lipidomics emerges as a major area in ASD research.

Genomic exploration of pediatric neurological disorders: a case series

BACKGROUND

Pediatric neurological disorders include neurodegenerative diseases causing cognitive impairment and vision loss. They are one of the important causes of morbidity and mortality in children with diverse etiologies. Diagnosis is difficult despite genetic work, and a final diagnosis can be achieved in only 60% of cases.

CASE PRESENTATION

We explore three Indian cases of pediatric neurological diseases (with age presented at the clinic), viz. arthrogryposis (8 years), autism (18 months), and congenital bilateral cataract (3 years), by analyzing clinical exomes. In this work, we attempt to understand rare neurological disorders in an Indian pediatric cohort using exome studies.

CONCLUSION

We used our benchmarked CONVEX pipeline for screening consensus variants, wherein EIF2B2 was found to be inherently pathogenic. We map the association of variants and genes and disease correlation to neuroleptic malignant syndrome, which matches the phenotype to the cases.

Research progress on melatonin, 5-HT, and orexin in sleep disorders of children with autism spectrum disorder

Sleep disorders are among the common comorbidities of autism spectrum disorder (ASD), which not only affect the daily life and learning ability of children but may also exacerbate other symptoms of ASD, seriously impacting the quality of life of children and their families. Given this, understanding the neurobiological mechanisms of sleep disorders in children with ASD has significant research value for developing effective intervention strategies. Melatonin, 5-hydroxytryptamine (5-HT), and orexin are key neurotransmitters that regulate the sleep-wake cycle. Through in-depth analysis of the biological functions and regulatory pathways of these neurotransmitters, new perspectives may be provided for personalized treatment of sleep disorders in children with ASD. This article reviews the research progress on melatonin, 5-HT, and orexin in sleep disorders among children with ASD, focusing on exploring the mechanisms of these key neurotransmitters in sleep disorders of children with ASD and how they affect the sleep-wake cycle, providing a theoretical basis for improving the sleep quality of children with ASD.

The neurobiological mechanisms underlying the effects of exercise interventions in autistic individuals

Autism spectrum disorder is a pervasive and heterogeneous neurodevelopmental condition characterized by social communication difficulties and rigid, repetitive behaviors. Owing to the complex pathogenesis of autism, effective drugs for treating its core features are lacking. Nonpharmacological approaches, including education, social-communication, behavioral and psychological methods, and exercise interventions, play important roles in supporting the needs of autistic individuals. The advantages of exercise intervention, such as its low cost, easy implementation, and high acceptance, have garnered increasing attention. Exercise interventions can effectively improve the core features and co-occurring conditions of autism, but the underlying neurobiological mechanisms are unclear. Abnormal changes in the gut microbiome, neuroinflammation, neurogenesis, and synaptic plasticity may individually or interactively be responsible for atypical brain structure and connectivity, leading to specific autistic experiences and characteristics. Interestingly, exercise can affect these biological processes and reshape brain network connections, which may explain how exercise alleviates core features and co-occurring conditions in autistic individuals. In this review, we describe the definition, diagnostic approach, epidemiology, and current support strategies for autism; highlight the benefits of exercise interventions; and call for individualized programs for different subtypes of autistic individuals. Finally, the possible neurobiological mechanisms by which exercise improves autistic features are comprehensively summarized to inform the development of optimal exercise interventions and specific targets to meet the needs of autistic individuals.

Probing Autism and ADHD subtypes using cortical signatures of the T1w/T2w-ratio and morphometry

Autism spectrum disorder (ASD) and attention-deficit/hyperactivity disorder (ADHD) are neurodevelopmental conditions that share genetic etiology and frequently co-occur. Given this comorbidity and well-established clinical heterogeneity, identifying individuals with similar brain signatures may be valuable for predicting clinical outcomes and tailoring treatment strategies. Cortical myelination is a prominent developmental process, and its disruption is a candidate mechanism for both disorders. Yet, no studies have attempted to identify subtypes using T1w/T2w-ratio, a magnetic resonance imaging (MRI) based proxy for intracortical myelin. Moreover, cortical variability arises from numerous biological pathways, and multimodal approaches can integrate cortical metrics into a single network. We analyzed data from 310 individuals aged 2.6-23.6 years, obtained from the Province of Ontario Neurodevelopmental (POND) Network consisting of individuals diagnosed with ASD (n = 136), ADHD (n = 100), and typically developing (TD) individuals (n = 74). We first tested for differences in T1w/T2w-ratio between diagnostic categories and controls. We then performed unimodal (T1w/T2w-ratio) and multimodal (T1w/T2w-ratio, cortical thickness, and surface area) spectral clustering to identify diagnostic-blind subgroups. Linear models revealed no statistically significant case-control differences in T1w/T2w-ratio. Unimodal clustering mostly isolated single individual- or minority clusters, driven by image quality and intensity outliers. Multimodal clustering suggested three distinct subgroups, which transcended diagnostic boundaries, showing separate cortical patterns but similar clinical and cognitive profiles. T1w/T2w-ratio features were the most relevant for demarcation, followed by surface area. While our analysis revealed no significant case-control differences, multimodal clustering incorporating the T1w/T2w-ratio among cortical features holds promise for identifying biologically similar subsets of individuals with neurodevelopmental conditions.

Molecular switch of the dendrite-to-spine transport of TDP-43/FMRP-bound neuronal mRNAs and its impairment in ASD

BACKGROUND

Regulation of messenger RNA (mRNA) transport and translation in neurons is essential for dendritic plasticity and learning/memory development. The trafficking of mRNAs along the hippocampal neuron dendrites remains translationally silent until they are selectively transported into the spines upon glutamate-induced receptor activation. However, the molecular mechanism(s) behind the spine entry of dendritic mRNAs under metabotropic glutamate receptor (mGluR)-mediated neuroactivation and long-term depression (LTD) as well as the fate of these mRNAs inside the spines are still elusive.

METHOD

Different molecular and imaging techniques, e.g., immunoprecipitation (IP), RNA-IP, Immunofluorescence (IF)/fluorescence in situ hybridization (FISH), live cell imaging, live cell tracking of RNA using beacon, and mouse model study are used to elucidate a novel mechanism regulating dendritic spine transport of mRNAs in mammalian neurons.

RESULTS

We demonstrate here that brief mGluR1 activation-mediated dephosphorylation of pFMRP (S499) results in the dissociation of FMRP from TDP-43 and handover of TDP-43/Rac1 mRNA complex from the dendritic transport track on microtubules to myosin V track on the spine actin filaments. Rac1 mRNA thus enters the spines for translational reactivation and increases the mature spine density. In contrast, during mGluR1-mediated neuronal LTD, FMRP (S499) remains phosphorylated and the TDP-43/Rac1 mRNA complex, being associated with kinesin 1-FMRP/cortactin/drebrin, enters the spines owing to Ca2+-dependent microtubule invasion into spines, but without translational reactivation. In a VPA-ASD mouse model, this regulation become anomalous.

CONCLUSIONS

This study, for the first time, highlights the importance of posttranslational modification of RBPs, such as the neurodevelopmental disease-related protein FMRP, as the molecular switch regulating the dendrite-to-spine transport of specific mRNAs under mGluR1-mediated neurotransmissions. The misregulation of this switch could contribute to the pathogenesis of FMRP-related neurodisorders including the autism spectrum disorder (ASD). It also could indicate a molecular connection between ASD and neurodegenerative disease-related protein TDP-43 and opens up a new perspective of research to elucidate TDP-43 proteinopathy among patients with ASD.

Microalgae-based bacteria for oral treatment of ASD through enhanced intestinal colonization and homeostasis

Rationale: Exogenous supplementation of beneficial intestinal bacteria can alleviate the behavioural symptoms of psychiatric disorders, such as autism spectrum disorder (ASD), through gut-brain interactions. However, the application of beneficial bacteria, such as Lactobacillus reuteri (L. reuteri), for treating ASD is hindered by limited gut colonization. Methods: Utilizing Spirulina platensis (SP) as a natural microcarrier for intestinal bacteria, a safer and more natural binding approach was employed to bind intestinal bacteria to the surface of SP to produce SP-intestinal bacteria. Due to the high adhesion efficiency and long residence time of SP in the intestines, SP-intestinal bacteria exhibit stronger intestinal colonization ability and better therapeutic effects on ASD. Results: SP is an effective carrier that can bind and deliver bacteria of different shapes and with different gram-staining properties. SP-intestinal bacteria exhibited enhanced colonization capabilities both ex vivo and in vivo. Further research showed that SP-L. reuteri had greater intestinal colonization efficiency than L. reuteri. SP-L. reuteri showed a stronger therapeutic effect on alleviating social deficits in an ASD mouse model by modulating the gut microbiota, enhancing intestinal barrier integrity, reducing lipopolysaccharide entry into the blood and mediating the neuroinflammatory response in the paraventricular thalamic nucleus. Conclusions: This study reports a microalgae-assisted intestinal bacterial delivery system for enhancing intestinal bacterial transplantation for gut-brain axis- or other intestinal-related diseases.

Unraveling pathogenesis and potential biomarkers for autism spectrum disorder associated with HIF1A pathway based on machine learning and experiment validation

BACKGROUND

Autism spectrum disorder (ASD) is a neurodevelopmental disorder with a high social burden and limited treatments. Hypoxic condition of the brain is considered an important pathological mechanism of ASD. HIF1A is a key participant in brain hypoxia, but its contribution to the pathophysiological landscape of ASD remains unclear.

METHODS

ASD-related datasets were obtained from GEO database, and HIF1A-related genes from GeneCards. Co-expression module analysis identified module genes, which were intersected with HIF1A-related genes to identify common genes. Machine learning identified hub genes from intersection genes and PPI networks were constructed to explore relationships among hub and HIF1A. Single-cell RNA sequencing analyzed hub gene distribution across cell clusters. ASD mouse model was created by inducing maternal immune activation (MIA) with poly(I:C) injections, verified through behavioral tests. Validation of HIF1A pathway and hub genes was confirmed through Western Blot, qPCR, and immunofluorescence in ASD mice and microglia BV-2 cells.

RESULTS

Using CEMiTool and GeneCards, 45 genes associated with ASD and HIF1A pathway were identified. Machine learning identified CDKN1A, ETS2, LYN, and SLC16A3 as potential ASD diagnostic markers. Single-cell sequencing pinpointed activated microglia as key immune cells. Behavioral tests showed MIA offspring mice exhibited typical ASD-like behaviors. Immunofluorescence confirmed the activation of microglia and HIF1A pathway in frontal cortex of ASD mice. Additionally, IL-6 contributed to ASD by activating JUN/HIF1A pathway, affecting CDKN1A, LYN, and SLC16A3 expression in microglia.

CONCLUSIONS

HIF1A-related genes CDKN1A, ETS2, LYN, and SLC16A3 are strong diagnostic markers for ASD and the activation of IL-6/JUN/HIF1A pathway in microglia contributes to the pathogenesis of ASD.

tVNS alters inflammatory response in adult VPA-induced mouse model of autism: evidence for sexual dimorphism

Autism is a neurodevelopmental disorder with limited treatment alternatives and which incidence is increasing. Some research suggests that vagus nerve simulation might lead to the reduction of certain symptom. Therefore, we aimed to examine the effect of bilateral transcutaneous auricular vagus nerve stimulation (tVNS) on the inflammatory response in an adult valproic acid (VPA) induced mouse (C57BL6) model of autism for the first time. The autism model was induced by oral VPA administration (600 mg·kg-1) to C57BL/6 pregnant mice on E12.5 days. The study included three groups: the VPA Transcutaneous Auricular Stimulation Group (VPA + tVNS), the VPA Control Group (VPA + sham), and the Healthy Control Group (Control + sham). Each group included 16 mice (8 M/8 F). Our results show that serum IL-1β and IL-6 levels were significantly higher in male VPA-exposed mice than controls. However, IL-1β was significantly lower, and IL-6, TNF- α, and IL-22 were not different in female VPA-exposed mice compared to the control group. Brain NLRP3 levels were significantly higher in both sexes in the VPA autism model (P < 0.05). tVNS application increased brain NLRP3 levels in both sexes and reduced serum IL-1β levels in male mice. We conclude that cytokine dysregulation is associated with the VPA-induced adult autism model, and the inflammatory response is more pronounced in male mice. tVNS application altered the inflammatory response and increased brain NLPR3 levels in both sexes. Further studies are needed to understand the beneficial or detrimental role of the inflammatory response in autism and its sexual dimorphism.

IUPHAR review: Targeted therapies of signaling pathways based on the gut microbiome in autism spectrum disorders: Mechanistic and therapeutic applications

Autism spectrum disorders (ASD) are complex neurodevelopmental disorders characterized by impairments in social interaction, communication and repetitive activities. Gut microbiota significantly influences behavior and neurodevelopment by regulating the gut-brain axis. This review explores gut microbiota-influenced treatments for ASD, focusing on their therapeutic applications and mechanistic insights. In addition, this review discusses the interactions between gut microbiota and the immune, metabolic and neuroendocrine systems, focusing on crucial microbial metabolites including short-chain fatty acids (SCFAs) and several neurotransmitters. Furthermore, the review explores various therapy methods including fecal microbiota transplantation, dietary modifications, probiotics and prebiotics and evaluates their safety and efficacy in reducing ASD symptoms. The discussion shows the potential of customized microbiome-based therapeutics and the integration of multi-omics methods to understand the underlying mechanisms. Moreover, the review explores the intricate relationship between gut microbiota and ASD, aiming to develop innovative therapies that utilize the gut microbiome to improve the clinical outcomes of ASD patients. Microbial metabolites such as neurotransmitter precursors, tryptophan metabolites and SCFAs affect brain development and behavior. Symptoms of ASD are linked to changes in these metabolites. Dysbiosis in the gut microbiome may impact neuroinflammatory processes linked to autism, negatively affecting immune signaling pathways. Research indicates that probiotics and prebiotics can improve gut microbiota and alleviate symptoms in ASD patients. Fecal microbiota transplantation may also improve behavioral symptoms and restore gut microbiota balance. The review emphasizes the need for further research on gut microbiota modification as a potential therapeutic approach for ASD, highlighting its potential in clinical settings.

Autism spectrum disorder and various mechanisms behind it

Autism Spectrum Disorder (ASD) is a complex and heterogeneous neurodevelopmental condition characterized by a range of social, communicative, and behavioral challenges. This comprehensive review delves into key aspects of ASD. Clinical Overview and genetic features provide a foundational understanding of ASD, highlighting the clinical presentation and genetic underpinnings that contribute to its complexity. We explore the intricate neurobiological mechanisms at play in ASD, including structural and functional differences that may underlie the condition's hallmark traits. Emerging research has shed light on the role of the immune system and neuroinflammation in ASD. This section investigates the potential links between immunological factors and ASD, offering insights into the condition's pathophysiology. We examine how atypical functional connectivity and alterations in neurotransmitter systems may contribute to the unique cognitive and behavioral features of ASD. In the pursuit of effective interventions, this section reviews current therapeutic strategies, ranging from behavioral and educational interventions to pharmacological approaches, providing a glimpse into the diverse and evolving landscape of ASD treatment. This holistic exploration of mechanisms in ASD aims to contribute to our evolving understanding of the condition and to guide the development of more targeted and personalized interventions for individuals living with ASD.

Investigating brain-gut microbiota dynamics and inflammatory processes in an autistic-like rat model using MRI biomarkers during childhood and adolescence

Autism spectrum disorder (ASD) is characterized by social interaction deficits and repetitive behaviors. Recent research has linked that gut dysbiosis may contribute to ASD-like behaviors. However, the exact developmental time point at which gut microbiota alterations affect brain function and behavior in patients with ASD remains unclear. We hypothesized that ASD-related brain microstructural changes and gut dysbiosis induce metabolic dysregulation and proinflammatory responses, which collectively contribute to the social behavioral deficits observed in early childhood. We used an autistic-like rat model that was generated via prenatal valproic acid exposure. We analyzed brain microstructural changes using diffusion tensor imaging (DTI) and examined microbiota, blood, and fecal samples for inflammation biomarkers. The ASD model rats exhibited significant brain microstructural changes in the anterior cingulate cortex, hippocampus, striatum, and thalamus; reduced microbiota diversity (Prevotellaceae and Peptostreptococcaceae); and altered metabolic signatures. The shift in microbiota diversity and density observed at postnatal day (PND) 35, which is a critical developmental period, underscored the importance of early ASD interventions. We identified a unique metabolic signature in the ASD model, with elevated formate and reduced acetate and butyrate levels, indicating a dysregulation in short-chain fatty acid (SCFA) metabolism. Furthermore, increased astrocytic and microglial activation and elevated proinflammatory cytokines-interleukin-1 beta (IL-1β), interleukin-6 (IL-6), interferon-gamma (IFN-γ), and tumor necrosis factor-alpha (TNF-α)-were observed, indicating immune dysregulation. This study provided insights into the complex interplay between the brain and the gut, and indicated DTI metrics as potential imaging-based biomarkers in ASD, thus emphasizing the need for early childhood interventions.

Tact Training with Augmentative Gestural Support for Language Disorder and Challenging Behaviors: A Case Study in an Italian Community-Based Setting

BACKGROUND

Gestures or manual signing are valid options for augmentative and alternative communication. However, the data in the literature are limited to a few neurodevelopmental disorders, and less is known about its application in the community setting.

OBJECTIVES

This case report explores the feasibility and preliminary efficacy of tact training with augmentative gestural support intervention for a child affected by a language disorder with challenging behaviors in a community setting.

METHODS

Baseline assessments were conducted using the Verbal Behavior Milestone Assessment and Placement Program (VB-MAPP) and Griffiths Mental Developmental Scale-III (GMDS-III). The patient received six months of standard treatment, consisting of neuropsychomotor and speech therapy each twice a week, with improved cooperation in proposed activities, but no improvement in language. Afterward, a total of 24 sessions of tact training with augmentative gestural support interventions were performed. Data were collected by two independent observers and analyzed to measure language and behavioral outcomes.

RESULTS

VB-MAPP scores increased form minimal communication and social interaction at T0 (baseline) to improved compliance but unchanged language skills at T1 (after standard therapy). After tack training with augmentative gestural support (T2), VB-MAPP scores showed significant improvements, with notable increases in verbal operants, independence in communication, and intersubjectivity skills. GMDS-III scores at T2 also demonstrated growth in social, communicative, and cognitive skills. Additionally, challenging behaviors were reduced by more than 70% and nearly resolved by the end of the intervention.

CONCLUSIONS

Personalized approaches appear to be essential for interventions tailored to developmental age. Further research is needed to determine the effectiveness of these approaches for other neurodevelopmental disorders, identify patient characteristics that may be predictors of outcomes to tailor the intervention, and explore the generalization of the results obtained with these strategies.

Assembloid models of cell-cell interaction to study tissue and disease biology

Neurodevelopment involves the migration, projection, and integration of various cell types across different regions of the nervous system. Assembloids are self-organizing systems formed by the integration of multiple organoids or cell types. Here, we outline the generation and application of assembloids. We illustrate how assembloids recapitulate critical neurodevelopmental steps, like migration, axon projection, and circuit formation, and how they are starting to provide biological insights into neuropsychiatric disorders. Additionally, we review how assembloids can be used to study properties emerging from cell-cell interactions within non-neural tissues. Overall, assembloid platforms represent a powerful tool for discovering human biology and developing therapeutics.

Relationship between global warming and autism spectrum disorder from 1990 to 2019

BACKGROUND

Despite mounting evidence linking neurological diseases with climate change, the link between autism spectrum disorder (ASD) and global warming has yet to be explored.

AIMS

To examine the relationship between the incidence of ASD and global warming from 1990 to 2019 and estimate the trajectory of ASD incidence from 2020 to 2100 globally.

METHOD

We extracted meteorological data from TerraClimate between 1990 and 2019. To estimate the association between global ASD incidence and temperature variation, we adopted a two-stage analysis strategy using a generalised additive regression model. Additionally, we projected future ASD incidence under four representative shared socioeconomic pathways (SSPs: 126, 245, 370 and 585) by bootstrapping.

RESULTS

Between 1990 and 2019, the global mean incidence of ASD in children under 5 years old was 96.9 per 100 000. The incidence was higher in males (147.5) than in females (46.3). A 1.0 °C increase in the temperature variation was associated with a 3.0% increased risk of ASD incidence. The association was stronger in boys and children living in a low/low-middle sociodemographic index region, as well as in low-latitude areas. According to the SSP585 scenario, by 2100, the children living in regions between 10 and 20° latitude, particularly in Africa, will experience a 68.6% increase in ASD incidence if the association remains. However, the SSP126 scenario is expected to mitigate this increase, with a less than 10% increase in incidence across all latitudes.

CONCLUSIONS

Our study highlights the association between climate change and ASD incidence worldwide. Prospective studies are warranted to confirm the association.

Perindopril Ameliorates Sodium Valproate-Induced Rat Model of Autism: Involvement of Sirtuin-1, JAK2/STAT3 Axis, PI3K/Akt/GSK-3β Pathway, and PPAR-Gamma Signaling

Background and Objectives: Autism is a developmental disability characterized by impairment of motor functions and social communication together with the development of repetitive or stereotyped behaviors. Neither the exact etiology or the curative treatment of autism are yet completely explored. The goals of this study were to evaluate the possible effects of perindopril on a rat model of autism and to elucidate the possible molecular mechanisms that may contribute to these effects. Materials and Methods: In a rat model of sodium valproate (VPA)-induced autism, the effect of postnatal administration of different doses of perindopril on growth and motor development, social and repetitive behaviors, sirtuin-1, oxidative stress and inflammatory markers, PI3K/Akt/GSK-3β pathway, JAK2/STAT3 axis, and PPAR-gamma signaling in the hippocampal tissues were investigated. The histopathological and electron microscopic changes elicited by administration of the different treatments were also investigated. Results: Perindopril dose-dependently combatted the effects of prenatal exposure to VPA on growth and maturation, motor development, and social and repetitive behaviors. In addition, the different doses of perindopril ameliorated the effects of prenatal exposure to VPA on sirtuin-1, oxidative stress and inflammatory markers, PI3K/Akt/GSK-3β pathway, JAK2/STAT3 axis, and PPAR-gamma signaling. These effects had a mitigating impact on VPA-induced histopathological and electron microscopic changes in the hippocampal tissues. Conclusions: Perindopril may emerge as a promising agent for amelioration of the pathologic changes of autism spectrum disorders.

Targeting epigenetic dysregulation in autism spectrum disorders

Autism spectrum disorders (ASD) comprise a range of neurodevelopmental pathologies characterized by deficits in social interaction and repetitive behaviors, collectively affecting almost 1% of the worldwide population. Deciphering the etiology of ASD has proven challenging due to the intricate interplay of genetic and environmental factors and the variety of molecular pathways affected. Epigenomic alterations have emerged as key players in ASD etiology. Their research has led to the identification of biomarkers for diagnosis and pinpointed specific gene targets for therapeutic interventions. This review examines the role of epigenetic alterations, resulting from both genetic and environmental influences, as a central causative factor in ASD, delving into its contribution to pathogenesis and treatment strategies.

Cerebellar impairments in genetic models of autism spectrum disorders: A neurobiological perspective

Functional and molecular alterations in the cerebellum are among the most widely recognised associates of autism spectrum disorders (ASD). As a critical computational hub of the brain, the cerebellum controls and coordinates a range of motor, affective and cognitive processes. Despite well-described circuits and integrative mechanisms, specific changes that underlie cerebellar impairments in ASD remain elusive. Studies in experimental animals have been critical in uncovering molecular pathology and neuro-behavioural correlates, providing a model for investigating complex disease conditions. Herein, we review commonalities and differences of the most extensively characterised genetic lines of ASD with reference to the cerebellum. We revisit structural, functional, and molecular alterations which may contribute to neurobehavioral phenotypes. The cross-model analysis of this study provides an integrated outlook on the role of cerebellar alterations in pathobiology of ASD that may benefit future translational research and development of therapies.

Transient CSF1R inhibition ameliorates behavioral deficits in Cntnap2 knockout and valproic acid-exposed mouse models of autism

Microglial abnormality and heterogeneity are observed in autism spectrum disorder (ASD) patients and animal models of ASD. Microglial depletion by colony stimulating factor 1-receptor (CSF1R) inhibition has been proved to improve autism-like behaviors in maternal immune activation mouse offspring. However, it is unclear whether CSF1R inhibition has extensive effectiveness and pharmacological heterogeneity in treating autism models caused by genetic and environmental risk factors. Here, we report pharmacological functions and cellular mechanisms of PLX5622, a small-molecule CSF1R inhibitor, in treating Cntnap2 knockout and valproic acid (VPA)-exposed autism model mice. For the Cntnap2 knockout mice, PLX5622 can improve their social ability and reciprocal social behavior, slow down their hyperactivity in open field and repetitive grooming behavior, and enhance their nesting ability. For the VPA model mice, PLX5622 can enhance their social ability and social novelty, and alleviate their anxiety behavior, repetitive and stereotyped autism-like behaviors such as grooming and marble burying. At the cellular level, PLX5622 restores the morphology and/or number of microglia in the somatosensory cortex, striatum, and hippocampal CA1 regions of the two models. Specially, PLX5622 corrects neurophysiological abnormalities in the striatum of the Cntnap2 knockout mice, and in the somatosensory cortex, striatum, and hippocampal CA1 regions of the VPA model mice. Incidentally, microglial dynamic changes in the VPA model mice are also reported. Our study demonstrates that microglial depletion and repopulation by transient CSF1R inhibition is effective, and however, has differential pharmacological functions and cellular mechanisms in rescuing behavioral deficits in the two autism models.

Key Synaptic Pathology in Autism Spectrum Disorder: Genetic Mechanisms and Recent Advances

Autism spectrum disorder (ASD) is a neurodevelopmental disorder characterized by impaired social interactions and verbal communication, accompanied by symptoms of restricted and repetitive patterns of behavior or interest. Over the past 30 years, the morbidity of ASD has increased in most areas of the world. Although the pathogenesis of ASD is not fully understood, it has been associated with over 1000 genes or genomic loci, indicating the importance and complexity of the genetic mechanisms involved. This review focuses on the synaptic pathology of ASD and particularly on genetic variants involved in synaptic structure and functions. These include SHANK, NLGN, NRXN, FMR1, and MECP2 as well as other potentially novel genes such as CHD8, CHD2, and SYNGAP1 that could be core elements in ASD pathogenesis. Here, we summarize several pathological pathways supporting the hypothesis that synaptic pathology caused by genetic mutations may be the pathogenic basis for ASD.

Alleviation of Autophagic Deficits and Neuroinflammation by Histamine H3 Receptor Antagonist E159 Ameliorates Autism-Related Behaviors in BTBR Mice

BACKGROUND/OBJECTIVES

Autism spectrum disorder (ASD) is a neurodevelopmental condition marked by social interaction difficulties, repetitive behaviors, and immune dysregulation with elevated pro-inflammatory markers. Autophagic deficiency also contributes to social behavior deficits in ASD. Histamine H3 receptor (H3R) antagonism is a potential treatment strategy for brain disorders with features overlapping ASD, such as schizophrenia and Alzheimer's disease.

METHODS

This study investigated the effects of sub-chronic systemic treatment with the H3R antagonist E159 on social deficits, repetitive behaviors, neuroinflammation, and autophagic disruption in male BTBR mice.

RESULTS

E159 (2.5, 5, and 10 mg/kg, i.p.) improved stereotypic repetitive behavior by reducing self-grooming time and enhancing spontaneous alternation in addition to attenuating social deficits. It also decreased pro-inflammatory cytokines in the cerebellum and hippocampus of treated BTBR mice. In BTBR mice, reduced expression of autophagy-related proteins LC3A/B and Beclin 1 was observed, which was elevated following treatment with E159, attenuating the disruption in autophagy. The co-administration with the H3R agonist MHA (10 mg/kg, i.p.) reversed these effects, highlighting the role of histaminergic neurotransmission in observed behavioral improvements.

CONCLUSIONS

These preliminary findings suggest the therapeutic potential of H3R antagonists in targeting neuroinflammation and autophagic disruption to improve ASD-like behaviors.

Modelling cell type-specific lncRNA regulatory network in autism with Cycle

BACKGROUND

Autism spectrum disorder (ASD) is a class of complex neurodevelopment disorders with high genetic heterogeneity. Long non-coding RNAs (lncRNAs) are vital regulators that perform specific functions within diverse cell types and play pivotal roles in neurological diseases including ASD. Therefore, exploring lncRNA regulation would contribute to deciphering ASD molecular mechanisms. Existing computational methods utilize bulk transcriptomics data to identify lncRNA regulation in all of samples, which could reveal the commonalities of lncRNA regulation in ASD, but ignore the specificity of lncRNA regulation across various cell types.

RESULTS

Here, we present Cycle (Cell type-specific lncRNA regulatory network) to construct the landscape of cell type-specific lncRNA regulation in ASD. We have found that each ASD cell type is unique in lncRNA regulation, and more than one-third and all cell type-specific lncRNA regulatory networks are characterized as scale-free and small-world, respectively. Across 17 ASD cell types, we have discovered 19 rewired and 11 stable modules, along with eight rewired and three stable hubs within the constructed cell type-specific lncRNA regulatory networks. Enrichment analysis reveals that the discovered rewired and stable modules and hubs are closely related to ASD. Furthermore, more similar ASD cell types tend to be connected with higher strength in the constructed cell similarity network. Finally, the comparison results demonstrate that Cycle is a potential method for uncovering cell type-specific lncRNA regulation.

CONCLUSION

Overall, these results illustrate that Cycle is a promising method to model the landscape of cell type-specific lncRNA regulation, and provides insights into understanding the heterogeneity of lncRNA regulation between various ASD cell types.

Decoding the genetic landscape of autism: A comprehensive review

BACKGROUND

Autism spectrum disorder (ASD) is a complex neurodevelopmental condition characterized by heterogeneous symptoms and genetic underpinnings. Recent advancements in genetic and epigenetic research have provided insights into the intricate mechanisms contributing to ASD, influencing both diagnosis and therapeutic strategies.

AIM

To explore the genetic architecture of ASD, elucidate mechanistic insights into genetic mutations, and examine gene-environment interactions.

METHODS

A comprehensive systematic review was conducted, integrating findings from studies on genetic variations, epigenetic mechanisms (such as DNA methylation and histone modifications), and emerging technologies [including Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR)-Cas9 and single-cell RNA sequencing]. Relevant articles were identified through systematic searches of databases such as PubMed and Google Scholar.

RESULTS

Genetic studies have identified numerous risk genes and mutations associated with ASD, yet many cases remain unexplained by known factors, suggesting undiscovered genetic components. Mechanistic insights into how these genetic mutations impact neural development and brain connectivity are still evolving. Epigenetic modifications, particularly DNA methylation and non-coding RNAs, also play significant roles in ASD pathogenesis. Emerging technologies like CRISPR-Cas9 and advanced bioinformatics are advancing our understanding by enabling precise genetic editing and analysis of complex genomic data.

CONCLUSION

Continued research into the genetic and epigenetic underpinnings of ASD is crucial for developing personalized and effective treatments. Collaborative efforts integrating multidisciplinary expertise and international collaborations are essential to address the complexity of ASD and translate genetic discoveries into clinical practice. Addressing unresolved questions and ethical considerations surrounding genetic research will pave the way for improved diagnostic tools and targeted therapies, ultimately enhancing outcomes for individuals affected by ASD.

AOP-based framework for predicting the joint action mode of di-(2-ethylhexyl) phthalate and bisphenol A co-exposure on autism spectrum disorder

Autism spectrum disorder (ASD), also known as autism, is a common, highly hereditary and heterogeneous neurodevelopmental disorder. The global prevalence of ASD among children continues to rise significantly, which is partially attributed to environmental pollution. It has been reported that pre- or post-natal exposure to di-(2-ethylhexyl) phthalate (DEHP) or bisphenol A (BPA), two prevalent environmental endocrine disruptors, increases the risk of ASD in offspring. Yet, the joint action mode linking DEHP and BPA with ASD is incompletely understood. This study aims to unravel the joint action mode of DEHP and BPA co-exposure on the development of ASD. An adverse outcome pathway (AOP) framework was employed to integrate data from multiple public database and construct chemical-gene-phenotype-disease networks (CGPDN) for DEHP- and BPA-related ASD. Topological analysis and comprehensive literature exploration of the CGPDN were performed to build the AOP. By analysis of shared key events (KEs) or phenotypes within the AOP or the CGPDN, we uncovered two AOPs, decreased N-methyl-D-aspartate receptor (NMDAR) and estrogen antagonism that were likely linked to ASD, both with moderate confidence. Our analysis further predicted that the joint action mode of DEHP and BPA related ASD was possibly an additive or synergistic action. Thus, we propose that the co-exposure to BPA and DEHP perhaps additively or synergistically increases the risk of ASD.

Calcium Hexacyanoferrate (III) Nanocatalyst Enables Redox Homeostasis for Autism Spectrum Disorder Treatment

Autism spectrum disorder (ASD) is a multifaced neurodevelopmental disorder with considerable heterogeneity, in which over-generated reactive oxygen species (ROS) induce a cascade of pathological changes, including cellular apoptosis and inflammatory responses. Given the complex etiology of ASD, no effective treatment is available for ASD. In this work, a specific catalytic nanoenzyme, calcium hexacyanoferrate (III) nanocatalysts (CaH NCs), is designed and engineered for efficient ASD treatment. CaH NCs can mimic the activities of natural enzymes including superoxide dismutase, peroxidase, catalase, and glutathione peroxidase, which mitigates intracellular excessive ROS and regulates redox equilibrium. These CaH NCs modulate mitochondrial membrane potential, elevate B-cell lymphoma-2 levels, and suppress pro-apoptotic proteins, including Caspase-3 and B-cell lymphoma-2-associated X, thus effectively reducing cellular apoptosis. Importantly, CaH NCs alleviate inflammation by upregulating anti-inflammatory cytokine interleukin-10 and downregulating pro-inflammatory factors, resulting in attenuated activation of microglial and astrocytic and subsequent reduction in neuroinflammation. Subsequently, CaH NCs enhance social abilities, decrease anxiety levels, ameliorate repetitive behaviors, and improve learning and memory in ASD animal models through inflammation regulation and apoptosis inhibition. The CaH NCs in managing and preventing ASD represents a paradigm shift in autism treatment, paving the alternative but efficient way for clinical interventions in neurological conditions.

Assessment of Expression of lncRNAs in Autistic Patients

Autism is a severe neurodevelopmental condition with unknown pathobiology. Nevertheless, multiple pieces of evidence suggest long non-coding RNA (lncRNA) dysregulation may be a contributing factor to this disorder. We investigated the association between the expression of five specific lncRNAs and autism. Peripheral blood was collected from 30 children with autism and 41 healthy children. The expression levels of PCAT-29, lincRNA-ROR, LINC-PINT, lincRNA-p21, and PCAT-1 were calculated. Then, their significance as biomarkers was also evaluated. The expression of LincRNA-ROR (27 times), LINC-PINT (5.26 times), LincRNA-p21 (4.54 times), PCAT-29 (16.66 times), and PCAT-1 (25 times) genes was significantly decreased in patients compared to the control group (p values < 0.05). According to the ROC curve analysis for each lncRNA, LincRNA-ROR, LINC-PINT, LincRNA-p21, PCAT-29, and PCAT-1 lncRNAs with diagnostic power of 0.85, 0.67, 0.64, 0.74, and 0.84, respectively, could be used as diagnostic biomarkers for autism. Additionally, significant positive correlations were reported between expression levels of PCAT-1 and PCAT-29 genes. Moreover, a positive correlation was detected between expression levels of lincRNA-ROR and patients' age. The current study shows further pieces of evidence for deregulation of lncRNAs in autistic patients that show these lncRNAs may play an important part in the pathogenesis of ASD. However, the role of lncRNA in the neurobiology of autism needs to be investigated further.

Structural Variations Identified in Patients with Autism Spectrum Disorder (ASD) in the Chinese Population: A Systematic Review of Case-Control Studies

Autistic spectrum disorder (ASD) is a neurodevelopmental disability characterised by the impairment of social interaction and communication ability. The alarming increase in its prevalence in children urged researchers to obtain a better understanding of the causes of this disease. Genetic factors are considered to be crucial, as ASD has a tendency to run in families. In recent years, with technological advances, the importance of structural variations (SVs) in ASD began to emerge. Most of these studies, however, focus on the Caucasian population. As a populated ethnicity, ASD shall be a significant health issue in China. This systematic review aims to summarise current case-control studies of SVs associated with ASD in the Chinese population. A list of genes identified in the nine included studies is provided. It also reveals that similar research focusing on other genetic backgrounds is demanded to manifest the disease etiology in different ethnic groups, and assist the development of accurate ethnic-oriented genetic diagnosis.

Pilot Study of Personalized Transcranial Magnetic Stimulation with Spectral Electroencephalogram Analyses for Assessing and Treating Persons with Autism

Autism spectrum condition (ASC) is a neurodevelopmental condition that is only partly responsive to prevailing interventions. ASC manifests core challenges in social skills, communication, and sensory function and by repetitive stereotyped behaviors, along with imbalances in the brain's excitatory (E) and inhibitory (I) signaling. Repetitive transcranial magnetic stimulation (rTMS) has shown promise in ASC and may be a useful addition to applied behavioral analysis (ABA), a gold-standard psychotherapeutic intervention. We report an open-label clinical pilot (initial) study in which ABA-treated ASC persons (n = 123) received our personalized rTMS protocol (PrTMS). PrTMS uses low TMS pulse intensities and continuously updates multiple cortical stimulation locales and stimulation frequencies based on the spectral EEG and psychometrics. No adverse effects developed, and 44% of subjects had ASC scale scores reduced to below diagnostic cutoffs. Importantly, in PrTMS responders, the spectral EEG regression flattened, implying a more balanced E/I ratio. Moreover, with older participants, alpha peak frequency increased, a positive correlate of non-verbal cognition. PrTMS may be an effective ASC intervention, offering improved cognitive function and overall symptomatology. This warrants further research into PrTMS mechanisms and specific types of subjects who may benefit, along with validation of the present results and exploration of broader clinical applicability.