Autism spectrum disorder at the crossroad between genes and environment: contributions, convergences, and interactions in ASD developmental pathophysiology

Involvement of disulfidptosis in the pathophysiology of autism spectrum disorder

Autism Spectrum Disorder (ASD) is a complex neurodevelopmental disorder, with oxidative stress recognized as a key pathogenic mechanisms. Oxidative stress disrupts intracellular dynamic- thiol/disulfide homeostasis (DTDH), potentially leading to disulfidptosis, a newly identified cell death mechanism. While studies suggest a link between DTDH and ASD, direct evidence implicating disulfidptosis in ASD pathogenesis remains limited. In this study, Mendelian randomization analysis revealed a significant causal association between disulfidptosis-related sulfhydryl oxidase 1 and 2 and ASD (OR1 = 0.883, OR2 = 0.924, p < 0.05). A positive correlation between protein disulfide-isomerase and cognitive performance (OR = 1.021, p < 0.01) further supported the role of disulfidptosis in ASD. Seven disulfidptosis-related genes (TIMP1, STAT3, VWA1, ADA, IL5, PF4, and TXNDC12) were identified and linked to immune cell alterations. A TF-miRNA-mRNA regulatory network and a predictive model (AUC = 0.759) were constructed and external validation datasets (AUC = 0.811). Immune infiltration analysis demonstrated altered expression of naive B cells and three other types of immune cells in ASD children. Animal experiments further validated the differential expression of key genes, highlighting their relevance to ASD pathogenesis. Animal experiments found that BTBR mice exhibit glucose starvation and NADPH depletion, with the specific indicator Slc7a11 being highly expressed. Silencing Slc7a11 can improve core ASD impairments in BTBR mice. CONCLUSION: This study establishes the first mechanistic link between disulfidptosis and ASD, identifies seven key genes and their regulatory network, and develops a predictive model with clinical utility. Animal experiments further confirmed the strong association between disulfidpotosis and ASD phenotypes. These findings offer novel therapeutic targets for modulating oxidative stress in ASD.

Selenium promotes neural development through the regulation of GPX4 and SEPP1 in an iPSC-derived neuronal model

Selenium (Se) is incorporated into selenoproteins in the form of selenocysteine, which has biological functions associated with neural development. Unfortunately, the specific roles and mechanisms of selenoproteins at different stages of neuronal development are still unclear. Therefore, in this study, we successfully established a neuronal model derived from induced pluripotent stem cells (iPSC-iNeuron) and used Se nanoparticles (SeNPs@LNT) with high bioavailability to intervene at different stages of neural development in iPSC-iNeuron model. Interestingly, our results showed that SeNPs@LNT could not only accelerate the proliferation of neural progenitor cells (NPCs) by upregulating glutathione peroxidase 4 (GPX4) during the NPC stage, but also can promote neuronal differentiation by increasing selenoprotein P (SEPP1) during the neuronal stage, resulting in efficient and rapid neural development. In addition, further mechanistic studies showed that SeNPs@LNT can regulate selenoproteins by activating the PI3K/Akt/Nrf2 signaling pathway, thereby affecting neuronal development. Notably, Further analysis of ASD patients in National Center for Biotechnology Information single-cell RNA-seq datasets also revealed significantly lower GPX4 expression within NRGN-expressing neurons in ASD patients, and GO enrichment analysis of genes in NRGN-expressing neurons from ASD patients showed that the downregulation of selenoproteins due to aberrant selenoprotein synthesis may be closely associated with decreased ATP synthesis resulting from abnormal mitochondrial and respiratory chain signaling pathways. Taken together, this study provides evidence that SeNPs@LNT exerts a beneficial effect on early neural development through the regulation of selenoproteins.

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.

Cerebrospinal fluid metabolomics in autistic regression reveals dysregulation of sphingolipids and decreased β-hydroxybutyrate

BACKGROUND

Autism is highly heritable, however actionable genetic findings are only found in a minority of patients. Many people with autism suffer loss of neurodevelopmental skills, known as autistic regression. The cause of regression is poorly understood, and the diagnostic and therapeutic pathways are lacking.

METHODS

We used untargeted metabolomics using a UPLC-Q-Exactive-HFx Mass Spectrometry to examine cerebrospinal fluid (CSF) from twenty-two patients with autistic regression compared to sixteen controls with neurodevelopmental disorders (but not autistic regression) and thirty-four controls with other neurological disease (headache, encephalitis, epilepsy). The twenty-two patients with autistic regression consisted of two groups: early (infantile) autistic regression <2 years of age (n = 8), and later regression of skills >4 years of age, often in the context of pre-existing developmental concerns (n = 14). Metabolites of interest were then quantified and validated using targeted assays.

FINDINGS

Untargeted case-control studies revealed good separation of patients from controls using multivariate analysis. β-hydroxybutyrate was significantly decreased in the CSF of patients with autistic regression, and the findings were validated using a targeted β-hydroxybutyrate assay. The sphingolipid, sphingosine-1-phosphate was significantly elevated in the discovery case-control studies, and sphingolipid metabolism pathways were also significantly dysregulated. We therefore developed a targeted metabolite assay of forty sphingolipids. After FDR correction, 21 of the 40 sphingolipids were significantly dysregulated (pFDR < 0.05) (Benjamini-Hochberg correction) in autistic regression compared to the neurodevelopmental controls, and 26 of the 40 sphingolipids were significantly dysregulated in autistic regression compared to other neurological controls, with elevated ceramides, hexosylceramides, sphingosines (including sphingosine-1-phosphate), and sulfatides. By contrast, sphingomyelin levels were generally decreased in autistic regression.

INTERPRETATION

Our data shows the potential utility of CSF metabolomics in the context of autistic regression, a clinical syndrome which has historically lacked pathophysiological biomarkers and disease modifying therapies.

FUNDING

Financial support for the study was granted by Dale NHMRC Investigator grant APP1193648, Petre Foundation, Cerebral Palsy Alliance, and Ainsworth and SCHF Neuroscience grant scheme.

Capsule DenseNet++: Enhanced autism detection framework with deep learning and reinforcement learning-based lifestyle recommendation

Autism Spectrum Disorder (ASD) is a complex neurological condition that impairs the ability to interact, communicate, and behave. It is becoming increasingly prevalent worldwide, with an increase in the number of young children diagnosed with ASD in Saudi Arabia. Timely identification and customized interventions are essential for enhancing developmental outcomes. However, existing diagnostic approaches are subjective, limiting the cost-effectiveness of their utilization and the uniformity of their outcomes across different communities. In light of these concerns, this study presents a two-phase deep learning framework for autism detection with lifestyle advice using reinforcement learning. In the first phase, the proposed framework utilizes advanced multiscale statistical techniques for feature extraction, such as measures of central tendencies, variability indices, and percentiles, incorporated with the CosmoNest Optimizer, which is a hybrid of the African Vultures Optimization Algorithm and Butterfly Optimization Algorithm. For accurate ASD identification, these optimized features were classified using Capsule DenseNet++, an advanced deep learning model that increases feature representation efficiency and interpretability. In the second stage, we implement a personalized lifestyle recommendation system using the Proximal Policy Optimization (PPO) algorithm, a reinforcement learning algorithm. In the PPO approach, lifestyle decisions are sequential actions aimed at optimizing interventions, therapies, or daily activities for a given person. The PPO system dynamically learns and adapts recommendations over time to improve its effectiveness. The framework was developed in Python and tested on two datasets: autism screening data and ASD screening data for toddlers in Saudi Arabia. The performance of the detection model was recorded in terms of accuracy (99.2 % and 99.3 %, respectively), precision (98.5 % and 98.7 %, respectively), sensitivity (98.7 % and 98.9 %, respectively), and F1-score (99.1 % and 99.2 %, respectively), demonstrating its robustness for ASD detection across both datasets.

Large-scale effects of prenatal inflammation and early life circadian disruption in mice: Implications for neurodevelopmental disorders

Around 80 % of individuals with neurodevelopmental disorders such as schizophrenia and autism spectrum disorders experience disruptions in sleep/circadian rhythms. We explored whether environmental circadian disruption interacts with prenatal infection, a risk factor for neurodevelopmental disorders, to induce sex-specific deficits in mice. A maternal immune activation (MIA) protocol was used by injecting pregnant mice with a viral mimic poly IC or saline at E9.5. Juvenile/adolescent male and female offspring (3-7 weeks old) were then subjected to a standard light:dark cycle (12:12LD) or to constant light (LL). Significant interactions between treatment (MIA, control) and lighting (12:12LD, LL) were evident in behaviors related to cognition, anxiety, and sociability. This pattern persisted in our RNA sequencing analysis of the dorsal hippocampus, where poly IC exposure resulted in numerous differentially expressed genes (DEGs) in males, while exposure to both poly IC and LL led to a marked reduction in DEGs. Through WGCNA analysis, many significant gene modules were found to be positively associated with poly IC (vs. saline) and LL (vs. LD) in males (fewer in females). Many of the identified hub-bottleneck genes were homologous to human genes associated with sleep/circadian rhythms and neurodevelopmental disorders as revealed by GWA studies. The MIA- and LL-associated modules were enriched in microglia gene signatures, which was paralleled by trends of effects of each of the factors on microglia morphology. In conclusion, in a mouse model of prenatal infection, circadian disruption induced by LL during adolescence acts as a modulator of the effects of MIA at behavioral, cellular, and molecular levels.

The Effects of Air Pollution on Neurological Diseases: A Narrative Review on Causes and Mechanisms

Air pollution has well-documented adverse effects on human health; however, its impact on neurological diseases remains underrecognized. The mechanisms by which various components of air pollutants contribute to neurological disorders are not yet fully understood. This review focuses on key air pollutants, including particulate matter (PM2.5 and PM10), nitrogen dioxide (NO2), ozone (O3), carbon monoxide (CO), and diesel exhaust particles (DEPs). This paper summarizes key findings on the effects of air pollution on neurological disorders, including autism spectrum disorder (ASD), attention deficit hyperactivity disorder (ADHD), Alzheimer's disease (AD), and Parkinson's disease (PD). Although the precise biological mechanisms remain to be fully elucidated, evidence suggests that multiple pathways are involved, including blood-brain barrier disruption, oxidative stress, inflammation, and the activation of microglia and astrocytes. This review underscores the role of environmental pollutants as significant risk factors for various neurological diseases and explores their mechanisms of action. By advancing our understanding of these interactions, this work aims to inform new insights for mitigating the adverse effects of air pollution on neurological diseases, ultimately contributing to the establishment of a cleaner and healthier environment for future generations.

Disruption of tryptophan metabolism by high-fat diet-triggered maternal immune activation promotes social behavioral deficits in male mice

Diet-related maternal obesity has been implicated in neurodevelopmental disorders in progeny. Although the precise mechanisms and effective interventions remain uncertain, our research elucidates some of these complexities. We established that a prenatal high-fat diet triggered maternal immune activation (MIA), marked by elevated serum lipopolysaccharide levels and inflammatory-cytokine overproduction, which dysregulated the maternal tryptophan metabolism promoting the accumulation of neurotoxic kynurenine metabolites in the embryonic brain. Interventions aimed at mitigating MIA or blocking the kynurenine pathway effectively rescued the male mice social performance. Furthermore, excessive kynurenine metabolites initiated oxidative stress response causing neuronal migration deficits in the fetal neocortex, an effect that was mitigated by administering the glutathione synthesis precursor N-Acetylcysteine, underscoring the central role of maternal immune-metabolic homeostasis in male mice behavioral outcomes. Collectively, our study accentuated the profound influence of maternal diet-induced immuno-metabolic dysregulation on fetal brain development and provided the preventive strategies for addressing neurodevelopmental disorders.

Understanding Sensory-Motor Disorders in Autism Spectrum Disorders by Extending Hebbian Theory: Formation of a Rigid-Autonomous Phase Sequence

Autism spectrum disorder is a neuropsychiatric disorder characterized by persistent deficits in social communication and social interaction and restricted, repetitive patterns of behavior, interests, or activities. The symptoms invariably appear in early childhood and cause significant impairment in social, occupational, and other important functions. Various abnormalities in the genetic, neurological, and endocrine systems of patients with autism spectrum disorder have been reported as the etiology; however, no clear factor leading to the onset of the disease has been identified. Additionally, higher order cognitive dysfunctions, which are represented by a lack of theory of mind, sensorimotor disorders, and memory-related disorders (e.g., flashbacks), have been reported in recent years, but no theoretical framework has been proposed to explain these behavioral abnormalities. In this study, we extended Hebb's biopsychology theory to provide a theoretical framework that comprehensively explains the various behavioral abnormalities observed in autism spectrum disorder. Specifically, we propose that a wide range of symptoms in autism spectrum disorder may be caused by the formation of a rigid-autonomous phase sequence (RAPS) in the brain. Using the RAPS formation theory, we propose a biopsychological mechanism that could be a target for the treatment of autism spectrum disorders.

Iron metabolism dysfunction in neuropsychiatric disorders: Implications for therapeutic intervention

Iron is a trace metal that takes part in the maintenance of body homeostasis by, for instance, aiding in energy production and immunity. A body of evidence now demonstrates that dysfunction in iron metabolism can have detrimental effects and is intricately associated with the development of neuropsychiatric disorders, including Major Depressive Disorder (MDD), anxiety, and schizophrenia. For instance, changes in serum and central nervous system (CNS) levels of iron and in proteins mediating iron metabolism have been documented in patients grappling with the aforementioned diseases. By contrast, targeting iron metabolism by using iron chelators, for instance, has proven to be effective in alleviating disease burden. Therefore, here we review the state-of-the-art regarding the role of iron metabolism and its dysfunction in the context of neuropsychiatric disorders. Furthermore, we discuss how targeting iron metabolism can be an effective therapeutic option to tackle this class of diseases. Finally, we discuss the mechanisms linking this dysfunction to behavioral changes in these disorders. Harnessing the knowledge of iron metabolism is not only key to the characterization of novel molecular targets and disease biomarkers but also crucial to drug repurposing and drug design.

Potential similarities in gut microbiota composition between autism spectrum disorder and neurotypical siblings: Insights from a comprehensive meta-analysis

BACKGROUND

Previous studies have explored the differences in gut microbiota (GM) between individuals with autism spectrum disorder (ASD) and neurotypical controls. However, factors such as diet, lifestyle, and environmental exposure influence GM, leading to significant variability, even among neurotypical individuals. Comparing the GM of ASD individuals with neurotypical siblings, who share similar genes and living conditions, may offer better insights into the GM mechanisms associated with ASD. Therefore, this study aims to analyze the GM composition in ASD by comparing it to that of neurotypical siblings, potentially identifying microbiota that influence ASD.

METHODS

We explored electronic databases up to July 2024, including EBSCOhost, PubMed, ScienceDirect, Web of Science, and Scopus. Meta-analysis using RevMan 5.4 assessed the relative abundance (RA) of gut bacteria from 8 phyla and 4 genera in ASD individuals and neurotypical siblings.

RESULTS

Eight studies were included, involving 248 people with ASD and 197 neurotypical siblings. Significant but unstable differences were observed in the RA of Bacteroidetes, Firmicutes, and Fusobacteria. No significant differences were found in the RA of Proteobacteria, Cyanobacteria, Actinobacteria, Verrucomicrobia, Tenericutes, or Bacteroides, Roseburia, Sutterella, Bifidobacterium.

CONCLUSIONS

GM composition in ASD individuals closely resembles that of neurotypical siblings, with only a few unstable differences. This suggests that other crucial bacteria or certain interacting environmental factors play a role. Further studies are needed to gather stronger evidence to uncover the differences in GM and their mechanisms in ASD people.

Chronic exposure to glucocorticoids amplifies inhibitory neuron cell fate during human neurodevelopment in organoids

Disruptions in the tightly regulated process of human brain development have been linked to increased risk for brain and mental illnesses. While the genetic contribution to these diseases is well established, important environmental factors have been less studied at molecular and cellular levels. Here, we used single-cell and cell type-specific techniques to investigate the effect of glucocorticoid (GC) exposure, a mediator of antenatal environmental risk, on gene regulation and lineage specification in unguided human neural organoids. We characterized the transcriptional response to chronic GC exposure during neural differentiation and studied the underlying gene regulatory networks by integrating single-cell transcriptomics with chromatin accessibility data. We found lasting cell type-specific changes that included autism risk genes and several transcription factors associated with neurodevelopment. Chronic GC exposure influenced lineage specification primarily by priming the inhibitory neuron lineage through transcription factors like PBX3. We provide evidence for convergence of genetic and environmental risk factors through a common mechanism of altering lineage specification.

Multiplexing cortical brain organoids for the longitudinal dissection of developmental traits at single-cell resolution

Dissecting human neurobiology at high resolution and with mechanistic precision requires a major leap in scalability, given the need for experimental designs that include multiple individuals and, prospectively, population cohorts. To lay the foundation for this, we have developed and benchmarked complementary strategies to multiplex brain organoids by pooling cells from different pluripotent stem cell (PSC) lines either during organoid generation (mosaic models) or before single-cell RNA sequencing (scRNA-seq) library preparation (downstream multiplexing). We have also developed a new computational method, SCanSNP, and a consensus call to deconvolve cell identities, overcoming current criticalities in doublets and low-quality cell identification. We validated both multiplexing methods for charting neurodevelopmental trajectories at high resolution, thus linking specific individuals' trajectories to genetic variation. Finally, we modeled their scalability across different multiplexing combinations and showed that mosaic organoids represent an enabling method for high-throughput settings. Together, this multiplexing suite of experimental and computational methods provides a highly scalable resource for brain disease and neurodiversity modeling.

Human pluripotent stem cell (hPSC)-derived models for autism spectrum disorder drug discovery

INTRODUCTION

Autism spectrum disorder (ASD) is a prevalent and complex neurodevelopmental disorder (NDD) with genetic and environmental origins. Currently, there are no effective pharmacological treatments targeting core ASD features. This leads to unmet medical needs of individuals with ASD and requires relevant human disease models recapitulating genetic and clinical heterogeneity to better understand underlying mechanisms and identify potential pharmacological therapies. Recent advancements in stem cell technology have enabled the generation of human pluripotent stem cell (hPSC)-derived two-dimensional (2D) and three-dimensional (3D) neural models, which serve as powerful tools for ASD modeling and drug discovery.

AREAS COVERED

This article reviews the applications of hPSC-derived 2D and 3D neural models in studying various forms of ASD using pharmacological perturbation and drug screenings, highlighting the potential use of these models to develop novel pharmacological treatment strategies for ASD.

EXPERT OPINION

hPSC-derived models recapitulate early human brain development spatiotemporally and have allowed patient-specific mechanistic investigation and therapeutic development using advanced molecular technologies, which will contribute to precision medicine for ASD therapy. Improvements are still required in hPSC-based models to further enhance their physiological relevance, clinical translation, and scalability for ASD drug discovery.

Can memantine treat autism? Answers from preclinical and clinical studies

Autism Spectrum Disorder (ASD) represents a clinical challenge due to its diverse behavioral symptoms and complex neuro-pathophysiology. Finding effective treatments that target the fundamental mechanisms of ASD remains a top priority. This narrative review presents the potential of the NMDA-receptor blocker memantine in managing ASD symptoms. Preclinical studies indicate that memantine could abrogate excitotoxicity, GABA/glutamate imbalance, reduced levels of brain-derived neurotrophic factor (BDNF), blood-brain barrier (BBB) leakage, and neuroinflammation, offering hope for managing core deficits associated with ASD like impaired social interaction and repetitive behaviors. However, clinical trials yield conflicting results, with some showing slight improvements in symptom severity and cognitive function, while others demonstrate limited efficacy. Further exploration of memantine's neurobiological mechanisms and refinement of treatment approaches are crucial for comprehensively tackling ASD complexities. Drawing from both animal models and clinical data, this review examines memantine's impact on core ASD symptoms, cognitive function, and potential mechanisms of action. Lastly, it identifies research gaps and proposes avenues for future investigations to enhance our understanding and utilization of memantine in ASD management.

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.

Implications of prenatal exposure to hyperandrogen for hippocampal neurodevelopment and autism-like behavior in offspring

Autism spectrum disorder (ASD) is a highly heterogeneous neurodevelopmental disorder that significantly jeopardizes the physical and mental well-being of children. Autism spectrum disorder results from a combination of environmental and genetic factors. Hyperandrogenic exposure during pregnancy increases their risk of developing autism. Nevertheless, the prenatal exposure to androgens affects offspring neurodevelopment and the underlying mechanisms have not been fully elucidated. In the present study, administration of excessive dihydrotestosterone (DHT) to pregnant mice was found to impair neuronal development and dendritic spine formation in offspring, inducing autism-like behaviors. Furthermore, through mRNA transcriptome sequencing technology, the key molecule Nr4a2 was identified during this process of change. Overexpression of Nr4a2 and treatment with amodiaquine (AQ) significantly improved the abnormal phenotypes in offspring caused by prenatal exposure to androgens. Overall, Nr4a2 emerges as a crucial molecule involved in the impairment of offspring neurodevelopment due to prenatal androgen exposure, which provides a new perspective for the in-depth study of the influencing factors and underlying mechanisms.

Medial prefrontal cortex circuitry and social behaviour in autism

Autism spectrum disorder (ASD) has proven to be highly enigmatic due to the diversity of its underlying genetic causes and the huge variability in symptom presentation. Uncovering common phenotypes across people with ASD and pre-clinical models allows us to better understand the influence on brain function of the many different genetic and cellular processes thought to contribute to ASD aetiology. One such feature of ASD is the convergent evidence implicating abnormal functioning of the medial prefrontal cortex (mPFC) across studies. The mPFC is a key part of the 'social brain' and may contribute to many of the changes in social behaviour observed in people with ASD. Here we review recent evidence for mPFC involvement in both ASD and social behaviours. We also highlight how pre-clinical mouse models can be used to uncover important cellular and circuit-level mechanisms that may underly atypical social behaviours in ASD. This article is part of the Special Issue on "PFC circuit function in psychiatric disease and relevant models".

Dysregulation of the mTOR-FMRP pathway and synaptic plasticity in an environmental model of ASD

Autism Spectrum Disorder (ASD) is caused by genetic, epigenetic, and environmental factors. Mutations in the human FMR1 gene, encoding the Fragile X Messenger Ribonucleoprotein 1 (FMRP), cause the most common monogenic form of ASD, the Fragile X Syndrome (FXS). This study explored the interaction between the FMR1 gene and a viral-like infection as an environmental insult, focusing on the impact on core autistic-like behaviors and the mGluR1/5-mTOR pathway. Pregnant heterozygous Fmr1 mouse females were exposed to maternal immune activation (MIA), by injecting the immunostimulant Poly (I:C) at the embryonic stage 12.5, simulating viral infections. Subsequently, ASD-like behaviors were analyzed in the adult offspring, at 8-10 weeks of age. MIA exposure in wild-type mice led to ASD-like behaviors in the adult offspring. These effects were specifically confined to the intrauterine infection, as immune activation at later stages, namely puberty (Pubertal Immune Activation, PIA) at post-natal day 35 or adulthood (Adult Immune Activation, AIA) at post-natal day 56, did not alter adult behavior. Importantly, combining the Fmr1 mutation with MIA exposure did not intensify core autistic-like behaviors, suggesting an occlusion effect. Mechanistically, MIA provided a strong activation of the mGluR1/5-mTOR pathway, leading to increased LTP and downregulation of FMRP specifically in the hippocampus. Finally, FMRP modulates mTOR activity via TSC2. These findings further strengthen the key role of the mGluR1/5-mTOR pathway in causing ASD-like core symptoms.

Is exposure to Bisphenol A associated with Attention-deficit hyperactivity disorder (ADHD) and associated executive or behavioral problems in children? A comprehensive systematic review

Numerous studies have investigated environmental risk factors in ADHD, and Bisphenol A (BPA), an endocrine disruptor, is suspected by several reviews. However, the quality of the studies has never been carefully assessed, leading us to rigorously examine associations between BPA exposure and ADHD and associated symptoms in children. Using PRISMA criteria, we conducted a systematic review on the MEDLINE/PubMed, Web of Science, EBSCOhost, PsycINFO, PsycARTICLES and Cochrane databases. We used the ROBINS-E tool to assess the quality, and the GRADE Approach. This study was registered with PROSPERO, CRD42023377150. Out of 10446 screened articles, 46 were included. Unlike pre-existing reviews, most studies failed to find clear links with ADHD or associated symptoms, with a high risk of bias and a very low level of certainty. Our systematic review reveals insufficient evidence regarding the impact of BPA on ADHD, despite some behavioral results that cannot be generalized. Future studies will require improved consideration of confounding factors and more precise sampling methods. This study did not receive specific funding.

Evaluation of the Efficacy of a Full-Spectrum Low-THC Cannabis Plant Extract Using In Vitro Models of Inflammation and Excitotoxicity

Evidence has accumulated that Cannabis-derived compounds have the potential to treat neuroinflammatory changes present in neurodevelopmental conditions such as autism spectrum disorder. However, research is needed on the specific brain health benefits of strains of whole Cannabis extract that are ready for commercial production. Here, we explore the anti-inflammatory and neuroprotective effects of NTI-164, a genetically unique high-cannabidiol (CBD), low-Δ9-tetrahydrocannabinol extract, and also CBD alone on BV-2 microglia and SHSY-5Y neurons. Inflammation-induced up-regulation of microglial inflammatory markers was significantly attenuated by NTI-164, but not by CBD. NTI-164 promoted undifferentiated neuron proliferation and differentiated neuron survival under excitotoxic conditions. These effects suggest the potential for NTI-164 as a treatment for neuropathologies.

Intestinal Symptoms Among Children aged 2-7 Years with Autism Spectrum Disorder in 13 Cities of China

BACKGROUND

Autism spectrum disorder (ASD) is a multifactorial, pervasive, neurodevelopmental disorder, of which intestinal symptoms collectively represent one of the most common comorbidities.

METHODS

In this study, 1,222 children with ASD and 1,206 typically developing (TD) children aged 2-7 years were enrolled from 13 cities in China. Physical measurement and basic information questionnaires were conducted in ASD and TD children. The Childhood Autism Rating Scale (CARS), Social Responsiveness Scale (SRS), and Autism Behavior Checklist (ABC) were used to evaluate the clinical symptoms of children with ASD. The six-item Gastrointestinal Severity Index (6-GSI) was used to evaluate the prevalence of intestinal symptoms in two groups.

RESULTS

The detection rates of constipation, stool odor, and total intestinal symptoms in ASD children were significantly higher than those in TD children (40.098% vs. 25.622%, 17.021% vs. 9.287%, and 53.601% vs. 41.294%, respectively). Autistic children presenting with intestinal comorbidity had significantly higher scores on the ABC, SRS, CARS, and multiple subscales than autistic children without intestinal symptoms, suggesting that intestinal comorbidity may exacerbates the core symptoms of ASD children.

CONCLUSION

Intestinal dysfunction was significantly more common in autistic than in TD children. This dysfunction may aggravate the core symptoms of children with ASD.

Dysregulated plasma autoantibodies are associated with B cell dysfunction in young Arab children with autism spectrum disorder in Qatar

Autism spectrum disorder (ASD) is a neurodevelopmental disorder characterized by impaired social interaction and communication, as well as the occurrence of stereotyped and repetitive behaviors. Previous studies have provided solid evidence of dysregulated immune system in ASD; however, limited studies have investigated autoantibody profiles in individuals with ASD. This study aims to screen plasma autoantibodies in a well-defined cohort of young children with ASD (n = 100) and their matched controls (n = 60) utilizing a high-throughput KoRectly Expressed (KREX) i-Ome protein-array technology. We identified differential protein expression of 16 autoantibodies in ASD, which were correlated with differential gene expression of these markers in independent ASD cohorts. Meanwhile, we identified a distinct list of 33 autoantibodies associated with ASD severity; several of which were correlated with maternal age and birth weight in ASD. In addition, we found dysregulated numbers of circulating B cells and activated HLADR+ B cells in ASD, which were correlated with altered levels of several autoantibodies. Further in-depth analysis of B cell subpopulations revealed an increased frequency of activated naïve B cells in ASD, as well as an association of resting naïve B cells and transitional B cells with ASD severity. Pathway enrichment analysis revealed disrupted MAPK signaling in ASD, suggesting a potential relevance of this pathway to altered autoantibodies and B cell dysfunction in ASD. Finally, we found that a combination of eight autoantibodies associated with ASD severity showed an area under the curve (ROC-AUC) of 0.937 (95% CI = 0.890, 0.983; p < 0.001), which demonstrated the diagnostic accuracy of the eight-marker signature in the severity classification of ASD cases. Overall, this study determined dysregulated autoantibody profiles and B cell dysfunction in children with ASD and identified an eight-autoantibody panel for ASD severity classification.

Therapeutic Potential of Fingolimod on Psychological Symptoms and Cognitive Function in Neuropsychiatric and Neurological Disorders

Neuropsychiatric and neurological disorders pose a significant global health burden, highlighting the need for innovative therapeutic approaches. Fingolimod (FTY720), a common drug to treat multiple sclerosis, has shown promising efficacy against various neuropsychiatric and neurological disorders. Fingolimod exerts its neuroprotective effects by targeting multiple cellular and molecular processes, such as apoptosis, oxidative stress, neuroinflammation, and autophagy. By modulating Sphingosine-1-Phosphate Receptor activity, a key regulator of immune cell trafficking and neuronal function, it also affects synaptic activity and strengthens memory formation. In the hippocampus, fingolimod decreases glutamate levels and increases GABA levels, suggesting a potential role in modulating synaptic transmission and neuronal excitability. Taken together, fingolimod has emerged as a promising neuroprotective agent for neuropsychiatric and neurological disorders. Its broad spectrum of cellular and molecular effects, including the modulation of apoptosis, oxidative stress, neuroinflammation, autophagy, and synaptic plasticity, provides a comprehensive therapeutic approach for these debilitating conditions. Further research is warranted to fully elucidate the mechanisms of action of fingolimod and optimize its use in the treatment of neuropsychiatric and neurological disorders.

Groups and Subgroups in Autism Spectrum Disorder (ASD) Considering an Advanced Integrative Model (AIM)

BACKGROUND

Autism spectrum disorder (ASD) is related to social communication difficulties, repetitive behaviors, and highly restricted interests beginning early in life. Currently, ASD is more diagnosed than in the past, and new models are needed. The Advanced Integrative Model (AIM) is a new model in which genes and concomitant medical problems to diagnosis (CMPD) and the impact of their rigorous and adequate treatment are considered.

METHODS

The role of a dynamic encephalopathy from which the individual response, susceptibilities in the brain and outside the brain, gut barrier and brain-blood-barrier permeabilities, and the plastic nature of the brain is proposed as a tool for diagnosis. The concomitant medical problems (CMP) are those at and outside the brain. The individual response to treatments of CMP is analyzed.

RESULTS

The AIM allows for classification into 3 main groups and 24 subgroups.

CONCLUSIONS

The groups and subgroups in ASD are obtained taking into account CMPD treatments and individual response.

Prenatal environmental risk factors for autism spectrum disorder and their potential mechanisms

Autism spectrum disorder (ASD) is a neurodevelopmental disorder that is globally increasing in prevalence. The rise of ASD can be partially attributed to diagnostic expansion and advocacy efforts; however, the interplay between genetic predisposition and modern environmental exposures is likely driving a true increase in incidence. A range of evidence indicates that prenatal exposures are critical. Infection during pregnancy, gestational diabetes, and maternal obesity are established risk factors for ASD. Emerging areas of research include the effects of maternal use of selective serotonin reuptake inhibitors, antibiotics, and exposure to toxicants during pregnancy on brain development and subsequent ASD. The underlying pathways of these risk factors remain uncertain, with varying levels of evidence implicating immune dysregulation, mitochondrial dysfunction, oxidative stress, gut microbiome alterations, and hormonal disruptions. This narrative review assesses the evidence of contributing prenatal environmental factors for ASD and associated mechanisms as potential targets for novel prevention strategies.

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.

Role of mitochondria-endoplasmic reticulum contacts in neurodegenerative, neurodevelopmental and neuropsychiatric conditions

Mitochondria-endoplasmic reticulum contacts (MERCs) mediate a close and continuous communication between both organelles that is essential for the transfer of calcium and lipids to mitochondria, necessary for cellular signalling and metabolic pathways. Their structural and molecular characterisation has shown the involvement of many proteins that bridge the membranes of the two organelles and maintain the structural stability and function of these contacts. The crosstalk between the two organelles is fundamental for proper neuronal function and is now recognised as a component of many neurological disorders. In fact, an increasing proportion of MERC proteins take part in the molecular and cellular basis of pathologies affecting the nervous system. Here we review the alterations in MERCs that have been reported for these pathologies, from neurodevelopmental and neuropsychiatric disorders to neurodegenerative diseases. Although mitochondrial abnormalities in these debilitating conditions have been extensively attributed to the high energy demand of neurons, a distinct role for MERCs is emerging as a new field of research. Understanding the molecular details of such alterations may open the way to new paths of therapeutic intervention.

Impact of interaction between individual genomes and preeclampsia on the severity of autism spectrum disorder symptoms

OBJECTIVES

Autism spectrum disorder (ASD) is a complex neurodevelopmental disorder. Prior research suggests that genetic susceptibility and environmental exposures, such as maternal preeclampsia (PE) during pregnancy, play key roles in ASD pathogenesis. However, the specific effects of the interaction between genetic and environmental factors on ASD phenotype severity remain unclear. This study aims to investigate how interactions between de novo variants (DNVs) and common variants in individual genomes and PE exposure affect ASD symptom severity by constructing a gene-environment model.

METHODS

Phenotypic data were obtained from the Simons Simplex Collection (SSC) database for idiopathic ASD patients aged 4-18. Subjects were divided based on maternal PE status: PE+ (exposed) and PE- (unexposed) groups. Those without DNVs were divided into DNV-PE+ and DNV-PE- groups, and those with DNVs into DNV+PE+ and DNV+PE- groups. Based on polygenic risk scores (PRS), subjects below the median were classified into PRSlowPE+ and PRSlowPE- groups, and those at or above the median into PRShighPE+ and PRShighPE- groups. Core ASD phenotypic assessed included adaptive and cognitive abilities, social reciprocity, language and communication skills, and repetitive behaviors. Adaptive and cognitive abilities were scored using adaptive behavior composite scores from the Vineland Adaptive Behavior Scales, Second Edition (VABS-II), along with verbal intelligence quotient (VIQ) and nonverbal intelligence quotient (NVIQ) scores from the SSC database. Social reciprocity abilities were measured using the social domain scores from the Autism Diagnostic Interview-Revised (ADI-R SD), social affective domain scores from the Autism Diagnostic Observation Schedule (ADOS SA), and normalized scores from the Social Responsiveness Scale (SRS). Language and communication abilities were assessed through verbal communication domain (ADI-R VC), nonverbal communication domain (ADI-R NVC) scores from ADI-R, and the communication and social domain scores from ADOS (ADOS CS). Repetitive behaviors were measured using the restricted and repetitive behaviors domain scores from ADI-R (ADI-R RRB), the repetitive domain scores from ADOS (ADOS REP), and the overall scores from the Repetitive Behavior Scale-Revised (RBS-R). Linear regression models were constructed to explore the impact of PE exposure and its interaction with individual genomes (including DNVs and common variants) on core ASD phenotypes. Additionally, ASD candidate genes associated with DNVs underwent gene ontology (GO) enrichment analysis via Metascape, and temporal and spatial gene expression patterns were examined using RNA sequencing (RNA-seq) data from the BrainSpan database.

RESULTS

A total of 2 439 ASD patients with recorded DNV information and confirmed PE exposure status were included, with 146 in the PE+ group and 2 293 in the PE- group. There was a trend toward differences between these two groups in SRS (β=2.01, P=0.08) and ADI-R NVC (β=-0.62, P=0.09). Among the 2 439 participants, there were 1 454 in the DNV-PE- group, 90 in the DNV-PE+ group, 839 in the DNV+PE- group, and 56 in the DNV+PE+ group. Analysis of the main effect of PE exposure showed significant impacts on SRS (β=3.71, P=0.01) and RBS-R (β=4.54, P=0.05). Interaction analysis between DNVs and PE exposure revealed a trend toward significance in SRS (β=-4.17, P=0.06). In the 2 236 participants with available PRS data, there were 1 033 in the PRSlowPE- group, 72 in the PRSlowPE+ group, 1 069 in the PRShighPE- group, and 62 in the PRShighPE+ group. Analysis of the main effect of PE exposure showed significant impacts on SRS (β=4.32, P<0.001) and RBS-R (β=5.87, P=0.02). The interaction between PRS and PE exposure showed significant effects on SRS (β=-4.90, P=0.03) and ADI-R NVC (β=-1.43, P=0.04), with trends in NVIQ (β=9.61, P=0.08) and RBS-R (β=-6.20, P=0.08). Additionally, DNV-enriched genes in PE-exposed patients were associated with regulatory of epithelial-to-mesenchymal transition and DNA-binding transcription factor activity. Temporal and spatial expression pattern analysis indicated that genes enriched in these regulatory processes showed higher expression levels prenatally compared to postnatally.

CONCLUSIONS

PE exposure, an environmental factor influencing ASD, is associated with increased ASD symptom severity. The interaction of PE exposure with genetic factors is crucial in modulating ASD phenotypes. Among PE-exposed individuals, ASD patients with high genetic risk for common variants may show improvements in social reciprocity and communication skills. In contrast, while DNVs may also aid in symptom improvement, their impact is less pronounced than that of common variants. These differences suggest that under similar PE exposure conditions, ASD patients with DNVs or high-risk common variants may exhibit varying degrees of symptom changes. ASD pathology research should consider the combined influence of genetic and environmental factors.

Assessing the COX-2/PGE2 Ratio and Anti-Nucleosome Autoantibodies as Biomarkers of Autism Spectrum Disorders: Using Combined ROC Curves to Improve Diagnostic Values

Autism spectrum disorder (ASD) is a neurodevelopmental condition marked by restricted and repetitive behaviors as well as difficulties with social interaction. Numerous studies have revealed aberrant lipid mediators and autoimmunity as a recognized etiological cause of ASD that is amenable to therapeutic intervention. In this study, the relationship between the relative cyclooxygenase-2/prostaglandin E2 ratio (COX-2/PGE2) as a lipid mediator marker and anti-nucleosome autoantibodies as an autoimmunity marker of ASD was investigated using multiple regression and combined receiver operating characteristic (ROC) curve analyses. The study also sought to identify the linear combination of these variables that optimizes the partial area under the ROC curves. There were forty ASD children and forty-two age- and gender-matched controls included in the current study. Using combined ROC curve analysis, a notable increase in the area under the curve was seen in the patient group, using the control group as a reference group. Additionally, it was reported that the combined markers had improved specificity and sensitivity. This study demonstrates how the predictive value of particular biomarkers associated with lipid metabolism and autoimmunity in children with ASD can be measured using a ROC curve analysis. This technique should help us better understand the etiological mechanism of ASD and how it may adversely affect cellular homeostasis, which is essential to maintaining healthy metabolic pathways. Early diagnosis and intervention may be facilitated by this knowledge.

Neonatal immune stimulation results in sex-specific changes in ultrasonic vocalizations but does not affect seizure susceptibility in neonatal mice

Neuroinflammation during the neonatal period has been linked to disorders such as autism and epilepsy. In this study, we investigated the early life behavioral consequences of a single injection of lipopolysaccharide (LPS) at postnatal day 10 (PD10) in mice. To assess deficits in communication, we performed the isolation-induced ultrasonic vocalizations (USVs) test at PD12. To determine if early life immune stimulus could alter seizure susceptibility, latency to flurothyl-induced generalized seizures was measured at 4 hours (hrs), 2 days, or 5 days after LPS injections. LPS had a sex-dependent effect on USV number. LPS-treated male mice presented significantly fewer USVs than LPS-treated female mice. However, the number of calls did not significantly differ between control and LPS for either sex. In male mice, we found that downward, short, and composite calls were significantly more prevalent in the LPS treatment group, while upward, chevron, and complex calls were less prevalent than in controls (p < 0.05). Female mice that received LPS presented a significantly higher proportion of short, frequency steps, two-syllable, and composite calls in their repertoire when compared with female control mice (p < 0.05). Seizure latency was not altered by early-life inflammation at any of the time points measured. Our findings suggest that early-life immune stimulation at PD10 disrupts vocal development but does not alter the susceptibility to flurothyl-induced seizures during the neonatal period. Additionally, the effect of inflammation in the disruption of vocalization is sex-dependent.

The Association Between Branched-Chain Amino Acid Concentrations and the Risk of Autism Spectrum Disorder in Preschool-Aged Children

Several studies have linked branched-chain amino acid (BCAA) metabolism disorders with autism spectrum disorder (ASD), but the results have been inconsistent. The purpose of this study was to explore the association between BCAA concentrations and the risk of ASD. A total of 313 participants were recruited from two tertiary referral hospitals from May 2018 to July 2021. Concentrations of BCAAs in dried blood spots were analyzed using liquid chromatography-tandem mass spectrometry-based analysis. Multivariate analyses and restricted cubic spline models were used to identify the association between BCAAs and the risk of ASD, and a nomogram was developed by using multivariate logistic regression and the risk was determined by receiver operating characteristic curve analysis and calibration curve analysis. Concentrations of total BCAA, valine, and leucine/isoleucine were higher in the ASD group, and all of them were positively and non-linearly associated with the risk of ASD even after adjusting for potential confounding factors such as age, gender, body mass index, and concentrations of BCAAs (P < 0.05). The nomogram integrating total BCAA and valine showed a good discriminant AUC value of 0.756 (95% CI 0.676-0.835). The model could yield net benefits across a reasonable range of risk thresholds. In the stratified analysis, the diagnostic ability of the model was more pronounced in children older than 3 years. We provide evidence that increased levels of BCAAs are associated with the risk of ASD, and the nomogram model of BCAAs presented here can serve as a marker for the early diagnosis of ASD.

Biomimetic nanoparticles with enhanced rapamycin delivery for autism spectrum disorder treatment via autophagy activation and oxidative stress modulation

Rationale: Autism spectrum disorder (ASD) represents a complex neurodevelopmental condition lacking specific pharmacological interventions. Given the multifaced etiology of ASD, there exist no effective treatment for ASD. Rapamycin (RAPA) can activate autophagy by inhibiting the mTOR pathway and has exhibited promising effects in treating central nervous system disorders; however, its limited ability to cross the blood-brain barrier (BBB) has hindered its clinical efficacy, leading to substantial side effects. Methods: To address this challenge, we designed a drug delivery system utilizing red blood cell membrane (CM) vesicles modified with SS31 peptides to enhance the brain penetration of RAPA for the treatment of autism. Results: The fabricated SCM@RAPA nanoparticles, with an average diameter of 110 nm, exhibit rapid release of RAPA in a pathological environment characterized by oxidative stress. In vitro results demonstrate that SCM@RAPA effectively activate cellular autophagy, reduce intracellular ROS levels, improve mitochondrial function, thereby ameliorating neuronal damage. SS31 peptide modification significantly enhances the BBB penetration and rapid brain accumulation of SCM@RAPA. Notably, SCM@RAPA nanoparticles demonstrate the potential to ameliorate social deficits, improve cognitive function, and reverse neuronal impairments in valproic acid (VPA)-induced ASD models. Conclusions: The therapeutic potential of SCM@RAPA in managing ASD signifies a paradigm shift in autism drug treatment, holding promise for clinical interventions in diverse neurological conditions.

Insulin-Like Growth Factor 1 Has the Potential to Be Used as a Diagnostic Tool and Treatment Target for Autism Spectrum Disorders

Autism spectrum disorder (ASD), a heterogeneous group of neurodevelopmental disorders, is characterized by social impairment and repetitive and stereotypic behaviors. Because of the lack of approved laboratory diagnostic markers and effective therapeutic medications, it is one of the most challenging diseases. Therefore, it is urgent to explore potential diagnosis markers or therapeutic targets. Insulin-like growth factor 1 (IGF-1) is a neurotrophic growth factor that enhances brain development. IGF-1 levels in body fluids are lower in preschool children with ASD than in typically developing children, which may serve as a potential diagnostic marker. In various ASD models associated with genetic or environmental exposure, IGF-1 treatment can improve core symptoms or pathological changes, including neuronal development, neural cell survival, balance of synaptic excitation and inhibition, neuroimmunology, and oxidative stress status. In March 2023 an IGF-1 derivative was approved as the first drug for treating Rett syndrome, an ASD-related neurodevelopmental disorder, to improve fundamental symptoms such as social communication. Thus, in this review, we present accumulating evidence of altered IGF-1 levels in ASD patients and the possible mechanisms, as well as evidence that IGF-1 treatment improves the pathophysiology in various ASD models. IGF-1 has the potential to be an early diagnosis marker and an effective therapeutic for ASD.

NASP gene contributes to autism by epigenetic dysregulation of neural and immune pathways

BACKGROUND

Epigenetics makes substantial contribution to the aetiology of autism spectrum disorder (ASD) and may harbour a unique opportunity to prevent the development of ASD. We aimed to identify novel epigenetic genes involved in ASD aetiology.

METHODS

Trio-based whole exome sequencing was conducted on ASD families. Genome editing technique was used to knock out the candidate causal gene in a relevant cell line. ATAC-seq, ChIP-seq and RNA-seq were performed to investigate the functional impact of knockout (KO) or mutation in the candidate gene.

RESULTS

We identified a novel candidate gene NASP (nuclear autoantigenic sperm protein) for epigenetic dysregulation in ASD in a Chinese nuclear family including one proband with autism and comorbid atopic disease. The de novo likely gene disruptive variant tNASP(Q289X) subjects the expression of tNASP to nonsense-mediated decay. tNASP KO increases chromatin accessibility, promotes the active promoter state of genes enriched in synaptic signalling and leads to upregulated expression of genes in the neural signalling and immune signalling pathways. Compared with wild-type tNASP, tNASP(Q289X) enhances chromatin accessibility of the genes with enriched expression in the brain. RNA-seq revealed that genes involved in neural and immune signalling are affected by the tNASP mutation, consistent with the phenotypic impact and molecular effects of nasp-1 mutations in Caenorhabditis elegans. Two additional patients with ASD were found carrying deletion or deleterious mutation in the NASP gene.

CONCLUSION

We identified novel epigenetic mechanisms mediated by tNASP which may contribute to the pathogenesis of ASD and its immune comorbidity.

Massively parallel in vivo Perturb-seq reveals cell-type-specific transcriptional networks in cortical development

Leveraging AAVs' versatile tropism and labeling capacity, we expanded the scale of in vivo CRISPR screening with single-cell transcriptomic phenotyping across embryonic to adult brains and peripheral nervous systems. Through extensive tests of 86 vectors across AAV serotypes combined with a transposon system, we substantially amplified labeling efficacy and accelerated in vivo gene delivery from weeks to days. Our proof-of-principle in utero screen identified the pleiotropic effects of Foxg1, highlighting its tight regulation of distinct networks essential for cell fate specification of Layer 6 corticothalamic neurons. Notably, our platform can label >6% of cerebral cells, surpassing the current state-of-the-art efficacy at <0.1% by lentivirus, to achieve analysis of over 30,000 cells in one experiment and enable massively parallel in vivo Perturb-seq. Compatible with various phenotypic measurements (single-cell or spatial multi-omics), it presents a flexible approach to interrogate gene function across cell types in vivo, translating gene variants to their causal function.

Mesenchymal Stem Cells and Purinergic Signaling in Autism Spectrum Disorder: Bridging the Gap between Cell-Based Strategies and Neuro-Immune Modulation

The prevalence of autism spectrum disorder (ASD) is still increasing, which means that this neurodevelopmental lifelong pathology requires special scientific attention and efforts focused on developing novel therapeutic approaches. It has become increasingly evident that neuroinflammation and dysregulation of neuro-immune cross-talk are specific hallmarks of ASD, offering the possibility to treat these disorders by factors modulating neuro-immunological interactions. Mesenchymal stem cell-based therapy has already been postulated as one of the therapeutic approaches for ASD; however, less is known about the molecular mechanisms of stem cell influence. One of the possibilities, although still underestimated, is the paracrine purinergic activity of MSCs, by which stem cells ameliorate inflammatory reactions. Modulation of adenosine signaling may help restore neurotransmitter balance, reduce neuroinflammation, and improve overall brain function in individuals with ASD. In our review article, we present a novel insight into purinergic signaling, including but not limited to the adenosinergic pathway and its role in neuroinflammation and neuro-immune cross-talk modulation. We anticipate that by achieving a greater understanding of the purinergic signaling contribution to ASD and related disorders, novel therapeutic strategies may be devised for patients with autism in the near future.

New advances in the diagnosis and treatment of autism spectrum disorders

Autism spectrum disorders (ASD) are a group of neurodevelopmental disorders that affect individuals' social interactions, communication skills, and behavioral patterns, with significant individual differences and complex etiology. This article reviews the definition and characteristics of ASD, epidemiological profile, early research and diagnostic history, etiological studies, advances in diagnostic methods, therapeutic approaches and intervention strategies, social and educational integration, and future research directions. The highly heritable nature of ASD, the role of environmental factors, genetic-environmental interactions, and the need for individualized, integrated, and technology-driven treatment strategies are emphasized. Also discussed is the interaction of social policy with ASD research and the outlook for future research and treatment, including the promise of precision medicine and emerging biotechnology applications. The paper points out that despite the remarkable progress that has been made, there are still many challenges to the comprehensive understanding and effective treatment of ASD, and interdisciplinary and cross-cultural research and global collaboration are needed to further deepen the understanding of ASD and improve the quality of life of patients.

Environmental pollution and extreme weather conditions: insights into the effect on mental health

Environmental pollution exposures, including air, soil, water, light, and noise pollution, are critical issues that may implicate adverse mental health outcomes. Extreme weather conditions, such as hurricanes, floods, wildfires, and droughts, may also cause long-term severe concerns. However, the knowledge about possible psychiatric disorders associated with these exposures is currently not well disseminated. In this review, we aim to summarize the current knowledge on the impact of environmental pollution and extreme weather conditions on mental health, focusing on anxiety spectrum disorders, autism spectrum disorders, schizophrenia, and depression. In air pollution studies, increased concentrations of PM2.5, NO2, and SO2 were the most strongly associated with the exacerbation of anxiety, schizophrenia, and depression symptoms. We provide an overview of the suggested underlying pathomechanisms involved. We highlight that the pathogenesis of environmental pollution-related diseases is multifactorial, including increased oxidative stress, systematic inflammation, disruption of the blood-brain barrier, and epigenetic dysregulation. Light pollution and noise pollution were correlated with an increased risk of neurodegenerative disorders, particularly Alzheimer's disease. Moreover, the impact of soil and water pollution is discussed. Such compounds as crude oil, heavy metals, natural gas, agro-chemicals (pesticides, herbicides, and fertilizers), polycyclic or polynuclear aromatic hydrocarbons (PAH), solvents, lead (Pb), and asbestos were associated with detrimental impact on mental health. Extreme weather conditions were linked to depression and anxiety spectrum disorders, namely PTSD. Several policy recommendations and awareness campaigns should be implemented, advocating for the advancement of high-quality urbanization, the mitigation of environmental pollution, and, consequently, the enhancement of residents' mental health.

Gestational hypothyroxinemia induces ASD-like phenotypes in behavior, proinflammatory markers, and glutamatergic protein expression in mouse offspring of both sexes

Background

The prevalence of autism spectrum disorder (ASD) has significantly risen in the past three decades, prompting researchers to explore the potential contributions of environmental factors during pregnancy to ASD development. One such factor of interest is gestational hypothyroxinemia (HTX), a frequent condition in pregnancy associated with cognitive impairments in the offspring. While retrospective human studies have linked gestational HTX to autistic traits, the cellular and molecular mechanisms underlying the development of ASD-like phenotypes remain poorly understood. This study used a mouse model of gestational HTX to evaluate ASD-like phenotypes in the offspring.

Methods

To induce gestational HTX, pregnant mice were treated with 2-mercapto-1-methylimidazole (MMI), a thyroid hormones synthesis inhibitor, in the tap-drinking water from embryonic days (E) 10 to E14. A separate group received MMI along with a daily subcutaneous injection of T4, while the control group received regular tap water during the entire pregnancy. Female and male offspring underwent assessments for repetitive, anxious, and social behaviors from postnatal day (P) 55 to P64. On P65, mice were euthanized for the evaluation of ASD-related inflammatory markers in blood, spleen, and specific brain regions. Additionally, the expression of glutamatergic proteins (NLGN3 and HOMER1) was analyzed in the prefrontal cortex and hippocampus.

Results

The HTX-offspring exhibited anxious-like behavior, a subordinate state, and impaired social interactions. Subsequently, both female and male HTX-offspring displayed elevated proinflammatory cytokines in blood, including IL-1β, IL-6, IL-17A, and TNF-α, while only males showed reduced levels of IL-10. The spleen of HTX-offspring of both sexes showed increased Th17/Treg ratio and M1-like macrophages. In the prefrontal cortex and hippocampus of male HTX-offspring, elevated levels of IL-17A and reduced IL-10 were observed, accompanied by increased expression of hippocampal NLGN3 and HOMER1. All these observations were compared to those observed in the Control-offspring. Notably, the supplementation with T4 during the MMI treatment prevents the development of the observed phenotypes. Correlation analysis revealed an association between maternal T4 levels and specific ASD-like outcomes.

Discussion

This study validates human observations, demonstrating for the first time that gestational HTX induces ASD-like phenotypes in the offspring, highlighting the need of monitoring thyroid function during pregnancy.

Zebrafish and nematodes as whole organism models to measure developmental neurotoxicity

Despite the growing epidemiological evidence of an association between toxin exposure and developmental neurotoxicity (DNT), systematic testing of DNT is not mandatory in international regulations for admission of pharmaceuticals or industrial chemicals. However, to date around 200 compounds, ranging from pesticides, pharmaceuticals and industrial chemicals, have been tested for DNT in the current OECD test guidelines (TG-443 or TG-426). There are calls for the development of new approach methodologies (NAMs) for DNT, which has resulted in a DNT testing battery using in vitro human cell-based assays. These assays provide a means to elucidate the molecular mechanisms of toxicity in humans which is lacking in animal-based toxicity tests. However, cell-based assays do not represent all steps of the complex process leading to DNT. Validated models with a multi-organ network of pathways that interact at the molecular, cellular and tissue level at very specific timepoints in a life cycle are currently missing. Consequently, whole model organisms are being developed to screen for, and causally link, new molecular targets of DNT compounds and how they affect whole brain development and neurobehavioral endpoints. Given the practical and ethical restraints associated with vertebrate testing, lower animal models that qualify as 3 R (reduce, refine and replace) models, including the nematode (Caenorhabditis elegans) and the zebrafish (Danio rerio) will prove particularly valuable for unravelling toxicity pathways leading to DNT. Although not as complex as the human brain, these 3 R-models develop a complete functioning brain with numerous neurodevelopmental processes overlapping with human brain development. Importantly, the main signalling pathways relating to (neuro)development, metabolism and growth are highly conserved in these models. We propose the use of whole model organisms specifically zebrafish and C. elegans for DNT relevant endpoints.

Gut microbial and clinical characteristics of individuals with autism spectrum disorder differ depending on the ecological structure of the gut microbiome

Understanding the relationship between the gut microbiome and autism spectrum disorder (ASD) is challenging due to the heterogeneous nature of ASD. Here, we analyzed the microbial and clinical characteristics of individuals with ASD using enterotypes. A total of 456 individuals participated in the study, including 249 participants with ASD, 106 typically developing siblings, and 101 controls. The alpha and beta diversities of the ASD, sibling, and control groups did not show significant differences. Analysis revealed a negative association between the Bifidobacterium longum group and the Childhood Autism Rating Scale, as well as a negative association between the Streptococcus salivarus group and the Social Responsiveness Scale (SRS) within the ASD group. When clustered based on microbial composition, participants with ASD exhibited two distinct enterotypes, E1 and E2. In the E2 group, the SRS score was significantly higher, and the Vineland Adaptive Behavior Scale score was significantly lower compared to the E1 group. Machine learning results indicated that the microbial species predicting SRS scores were distinct between the two enterotypes. Our study suggests that the microbial composition in individuals with ASD exhibits considerable variability, and the patterns of associations between the gut microbiome and clinical symptoms may vary depending on the enterotype.

Maternal separation stress through triggering of the neuro-immune response in the hippocampus induces autistic-like behaviors in male mice

Autism spectrum disorder (ASD) is the fastest-growing neurodevelopmental disease throughout the world. Neuro-immune responses from prenatal to adulthood stages of life induce developmental defects in synaptic signaling, neurotransmitter imbalance, and even structural changes in the brain. In this study, we aimed to focus on the possible role of neuroinflammatory response in the hippocampus in development of the autistic-like behaviors following maternal separation (MS) stress in mice. To do this, mice neonates daily separated from their mothers from postnatal day (PND) 2 to PND 14 for 3 h. During PND45-60, behavioral tests related to autistic-like behaviors including three-chamber sociability, Morris water maze (MWM), shuttle box, resident-intruder, and marble burying tests were performed. Then, hippocampi were dissected out, and the gene expression of inflammatory mediators including TNF-α, IL-1β, TLR4, HMGB1, and NLRP3 was assessed in the hippocampus using RT-PCR. Results showed that MS mice exerted impaired sociability preference, repetitive behaviors, impaired passive avoidance, and spatial memories. The gene expression of inflammatory mediators significantly increased in the hippocampi of MS mice. We concluded that MS stress probably via activating of the HMGB1/TLR4 signaling cascade in the hippocampus induced autistic-like behaviors in mice.

Genetic Alterations in a Large Population of Italian Patients Affected by Neurodevelopmental Disorders

Neurodevelopmental disorders are a group of complex multifactorial disorders characterized by cognitive impairment, communication deficits, abnormal behaviour, and/or motor skills resulting from abnormal neural development. Copy number variants (CNVs) are genetic alterations often associated with neurodevelopmental disorders. We evaluated the diagnostic efficacy of the array-comparative genomic hybridization (a-CGH) method and its relevance as a routine diagnostic test in patients with neurodevelopmental disorders for the identification of the molecular alterations underlying or contributing to the clinical manifestations. In the present study, we analysed 1800 subjects with neurodevelopmental disorders using a CGH microarray. We identified 208 (7%) pathogenetic CNVs, 2202 (78%) variants of uncertain significance (VOUS), and 504 (18%) benign CNVs in the 1800 patients analysed. Some alterations contain genes potentially related to neurodevelopmental disorders including CHRNA7, ANKS1B, ANKRD11, RBFOX1, ASTN2, GABRG3, SHANK2, KIF1A SETBP1, SNTG2, CTNNA2, TOP3B, CNTN4, CNTN5, and CNTN6. The identification of interesting significant genes related to neurological disorders with a-CGH is therefore an essential step in the diagnostic procedure, allowing a better understanding of both the pathophysiology of these disorders and the mechanisms underlying their clinical manifestations.

Association between interpregnancy interval and risk of autism spectrum disorder: a systematic review and Bayesian network meta-analysis

Although the risk of autism spectrum disorder (ASD) has been reported to be associated with interpregnancy intervals (IPIs), their association remains debatable due to inconsistent findings in existing studies. Therefore, the present study aimed to explore their association. PubMed, Embase, Web of Science, and the Cochrane Library were systematically retrieved up to May 25, 2022. An updated search was performed on May 25, 2023, to encompass recent studies. The quality of the included studies was assessed using the Newcastle-Ottawa Scale (NOS). Our primary outcome measures were expressed as adjusted odds ratios (ORs). Given various control measures for IPI and diverse IPI thresholds in the included studies, a Bayesian network meta-analysis was performed. Eight studies were included, involving 24,865 children with ASD and 2,890,289 children without ASD. Compared to an IPI of 24 to 35 months, various IPIs were significantly associated with a higher risk of ASD (IPIs < 6 months: OR = 1.63, 95% CI 1.53-1.74, n = 5; IPIs of 6-11 months: OR = 1.50, 95% CI 1.42-1.59, n = 4; IPIs of 12-23 months: OR = 1.19, 95% CI 1.12-1.23, n = 10; IPIs of 36-59 months: OR = 0.96, 95% CI 0.94-0.99, n = 2; IPIs of 60-119 months: OR = 1.15, 95% CI 1.10-1.20, n = 4; IPIs > 120 months: OR = 1.57, 95% CI 1.43-1.72, n = 4). After adjusting confounding variables, our analysis delineated a U-shaped restricted cubic spline curve, underscoring that both substantially short (< 24 months) and excessively long IPIs (> 72 months) are significantly correlated with an increased risk of ASD.  Conclusion: Our analysis indicates that both shorter and longer IPIs might predispose children to a higher risk of ASD. Optimal childbearing health and neurodevelopmental outcomes appear to be associated with a moderate IPI, specifically between 36 and 60 months. What is Known: • An association between autism spectrum disorder (ASD) and interpregnancy intervals (IPIs) has been speculated in some reports. • This association remains debatable due to inconsistent findings in available studies. What is New: • Our study delineated a U-shaped restricted cubic spline curve, suggesting that both shorter and longer IPIs predispose children to a higher risk of ASD. • Optimal childbearing health and neurodevelopmental outcomes appear to be associated with a moderate IPI, specifically between 36 and 60 months.

Cannabinoid treatment for the symptoms of autism spectrum disorder

INTRODUCTION

Autism spectrum disorder (ASD) is a neurodevelopmental disorder affecting approximately 3% of school-age children. The core symptoms are deficits in social communication and restricted and repetitive patterns of behavior. Associated problems in cognition, language, behavior, sleep and mood are prevalent. Currently, no established pharmacological treatment exists for core ASD symptoms. Risperidone and aripiprazole are used to manage associated irritability, but their effectiveness is limited and adverse events are common.

AREAS COVERED

This mini-review summarizes existing scientific literature and ongoing clinical trials concerning cannabinoid treatment for ASD. Uncontrolled case series have documented improvements in both core ASD symptoms and related behavioral challenges in children treated with cannabis extracts rich in cannabidiol (CBD). Placebo-controlled studies involving CBD-rich cannabis extracts and/or pure CBD in children with ASD have demonstrated mixed efficacy results. A similar outcome was observed in a placebo-controlled study of pure CBD addressing social avoidance in Fragile X syndrome. Importantly, these studies have shown relatively high safety and tolerability.

EXPERT OPINION

While current clinical data suggest the potential of CBD and CBD-rich cannabis extract in managing core and behavioral deficits in ASD, it is prudent to await the results of ongoing placebo-controlled trials before considering CBD treatment for ASD.

Severity of Autism Spectrum Disorder Symptoms Associated with de novo Variants and Pregnancy-Induced Hypertension

Genetic factors, particularly, de novo variants (DNV), and an environment factor, exposure to pregnancy-induced hypertension (PIH), were reported to be associated with risk of autism spectrum disorder (ASD); however, how they jointly affect the severity of ASD symptom is unclear. We assessed the severity of core ASD symptoms affected by functional de novo variants or PIH. We selected phenotype data from Simon's Simplex Collection database, used genotypes from previous studies, and created linear regression models. We found that ASD patients carrying DNV with PIH exposure had increased adaptive and cognitive ability, decreased social problems, and enhanced repetitive behaviors; however, there was no difference in patients without DNV between those with or without PIH exposure. In addition, the DNV genes carried by patients exposed to PIH were enriched in ubiquitin-dependent proteolytic processes, highlighting how candidate genes in pathways and environments interact. The results indicate the joint contribution of DNV and PIH to ASD.

Cranio-Facial Characteristics in Autism Spectrum Disorder: A Scoping Review

Autism spectrum disorders (ASD) consist of a complex group of neurodevelopmental disorders characterised by qualitative impairments of social interactions, communication abilities, and a limited, stereotyped, and repetitive selection of interests and activities. In light of the imperative to identify a possible biomarker for ASD, it has been determined that craniofacial anomalies serve as significant risk factors for neurodevelopmental disorders. The aim of this scoping review is to deepen the knowledge of the scientific literature related to cranio-facial characteristics in individuals with ASD, with a particular focus on recent research advancements. The review was performed by employing the search strings (("Autism Spectrum Disorder" OR autism OR ASD OR "Autism Spectrum") AND ("facial morphology" OR "facial phenotype")) on the databases PubMed/MEDLINE, Scopus, and ERIC as of March 9, 2023. The review comprised seven studies whose findings were obtained through quantitative analysis of Euclidean distances between anatomical landmarks. The examination of facial abnormalities represents a possible reliable diagnostic biomarker that could aid in the timely identification of ASD. Phenotypic characteristics that may serve as predictive indicators of the severity of autistic symptoms can be observed in certain individuals with ASD by applying anthropometric and instrumental measurements. The presence of a phenotype characterised by an increased intercanthal distance and a reduced facial midline height appears to be associated with a higher degree of severity in autistic symptoms. In addition, it is worth noting that facial asymmetry and facial masculinity can be considered reliable indicators for predicting a more severe manifestation of symptoms.

Interaction between Per- and Polyfluorinated Substances (PFAS) and Acetaminophen in Disease Exacerbation-Focusing on Autism and the Gut-Liver-Brain Axis

This review presents a new perspective on the exacerbation of autism spectrum disorder (ASD) by per- and polyfluoroalkyl substances (PFAS) through the gut-liver-brain axis. We have summarized evidence reported on the involvement of the gut microbiome and liver inflammation that led to the onset and exacerbation of ASD symptoms. As PFAS are toxicants that particularly target liver, this review has comprehensively explored the possible interaction between PFAS and acetaminophen, another liver toxicant, as the chemicals of interest for future toxicology research. Our hypothesis is that, at acute dosages, acetaminophen has the ability to aggravate the impaired conditions of the PFAS-exposed liver, which would further exacerbate neurological symptoms such as lack of social communication and interest, and repetitive behaviors using mechanisms related to the gut-liver-brain axis. This review discusses their potential interactions in terms of the gut-liver-brain axis and signaling pathways that may contribute to neurological diseases.

The Association between Long-Term DDT or DDE Exposures and an Altered Sperm Epigenome-a Cross-Sectional Study of Greenlandic Inuit and South African VhaVenda Men

BACKGROUND

The organochlorine dichlorodiphenyltrichloroethane (DDT) is banned worldwide owing to its negative health effects. It is exceptionally used as an insecticide for malaria control. Exposure occurs in regions where DDT is applied, as well as in the Arctic, where its endocrine disrupting metabolite, p , p ' -dichlorodiphenyldichloroethylene (p , p ' -DDE) accumulates in marine mammals and fish. DDT and p , p ' -DDE exposures are linked to birth defects, infertility, cancer, and neurodevelopmental delays. Of particular concern is the potential of DDT use to impact the health of generations to come via the heritable sperm epigenome.

OBJECTIVES

The objective of this study was to assess the sperm epigenome in relation to p , p ' -DDE serum levels between geographically diverse populations.

METHODS

In the Limpopo Province of South Africa, we recruited 247 VhaVenda South African men and selected 50 paired blood serum and semen samples, and 47 Greenlandic Inuit blood and semen paired samples were selected from a total of 193 samples from the biobank of the INUENDO cohort, an EU Fifth Framework Programme Research and Development project. Sample selection was based on obtaining a range of p , p ' -DDE serum levels (mean = 870.734 ± 134.030  ng / mL ). We assessed the sperm epigenome in relation to serum p , p ' -DDE levels using MethylC-Capture-sequencing (MCC-seq) and chromatin immunoprecipitation followed by sequencing (ChIP-seq). We identified genomic regions with altered DNA methylation (DNAme) and differential enrichment of histone H3 lysine 4 trimethylation (H3K4me3) in sperm.

RESULTS

Differences in DNAme and H3K4me3 enrichment were identified at transposable elements and regulatory regions involved in fertility, disease, development, and neurofunction. A subset of regions with sperm DNAme and H3K4me3 that differed between exposure groups was predicted to persist in the preimplantation embryo and to be associated with embryonic gene expression.

DISCUSSION

These findings suggest that DDT and p , p ' -DDE exposure impacts the sperm epigenome in a dose-response-like manner and may negatively impact the health of future generations through epigenetic mechanisms. Confounding factors, such as other environmental exposures, genetic diversity, and selection bias, cannot be ruled out. https://doi.org/10.1289/EHP12013.