Innate immune dysfunction and neuroinflammation in autism spectrum disorder (ASD)

Mouse strain-specific responses along the gut-brain axis upon fecal microbiota transplantation from children with autism

Several factors are linked to the pathophysiology of autism spectrum disorders (ASD); however, the molecular mechanisms of the condition remain unknown. As intestinal problems and gut microbiota dysbiosis are associated with ASD development and severity, recent studies have focused on elucidating the microbiota-gut-brain axis' involvement. This study aims to explore mechanisms through which gut microbiota might influence ASD. Briefly, we depleted the microbiota of conventional male BALB/cAnNCrl (Balb/c) and C57BL/6J (BL/6) mice prior to human fecal microbiota transplantation (hFMT) with samples from children with ASD or their neurotypical siblings. We found mouse strain-specific responses to ASD hFMT. Notably, Balb/c mice exhibit decreased exploratory and social behavior, and show evidence of intestinal, systemic, and central inflammation accompanied with metabolic shifts. BL/6 mice show less changes after hFMT. Our results reveal that gut microbiota alone induce changes in ASD-like behavior, and highlight the importance of mouse strain selection when investigating multifactorial conditions like ASD.

Dip2a regulates stress susceptibility in the basolateral amygdala

JOURNAL/nrgr/04.03/01300535-202506000-00025/figure1/v/2024-08-05T133530Z/r/image-tiff Dysregulation of neurotransmitter metabolism in the central nervous system contributes to mood disorders such as depression, anxiety, and post-traumatic stress disorder. Monoamines and amino acids are important types of neurotransmitters. Our previous results have shown that disco-interacting protein 2 homolog A (Dip2a) knockout mice exhibit brain development disorders and abnormal amino acid metabolism in serum. This suggests that DIP2A is involved in the metabolism of amino acid-associated neurotransmitters. Therefore, we performed targeted neurotransmitter metabolomics analysis and found that Dip2a deficiency caused abnormal metabolism of tryptophan and thyroxine in the basolateral amygdala and medial prefrontal cortex. In addition, acute restraint stress induced a decrease in 5-hydroxytryptamine in the basolateral amygdala. Additionally, Dip2a was abundantly expressed in excitatory neurons of the basolateral amygdala, and deletion of Dip2a in these neurons resulted in hopelessness-like behavior in the tail suspension test. Altogether, these findings demonstrate that DIP2A in the basolateral amygdala may be involved in the regulation of stress susceptibility. This provides critical evidence implicating a role of DIP2A in affective disorders.

Data independent acquisition proteomics and machine learning reveals that proteins associated with immunity are potential molecular markers for early diagnosis of autism

BACKGROUND

Early diagnosis of autism is critical to its treatment, but so far, there is no clear molecular marker for early diagnosis in children.

METHODS

We used data independent acquisition (DIA) mass spectrometry to compare protein expression in serum from 99 Chinese children with autism spectrum disorders with 70 healthy children.

RESULTS

We identified 347 downregulated and 394 upregulated proteins. Based on bioinformatics analysis, differential proteins were enriched in the immune system, immune disease, cell motility, and focal adhesion. Machine learning revealed a model with eight proteins (IGH c1898_heavy_IGHV3-33_IGHD3-9_IGHJ4, LYZ, IGL c1860_light_IGLV8-61_IGLJ2, SERPINA10, IG c1421_light_IGKV1-27_IGKJ4, rheumatoid factor RF-ET1, IGL c600_light_IGKV4-1_IGKJ4, and SELL) that were mostly associated with immunity, and accurate for diagnosis of autism. The protein family was verified by a logic-regression leave-one cross-validation method with bidirectional feature screening. The accuracy of this model was 0.9527, and the kappa coefficient was 0.9025.

CONCLUSIONS

Our study showed that immunity is closely related to the onset of autism and can be used for early screening of patients. A model with eight proteins (IGH c1898_heavy_IGHV3-33_IGHD3-9_IGHJ4, LYZ, IGL c1860_light_IGLV8-61_IGLJ2, SERPINA10, IG c1421_light_IGKV1-27_IGKJ4, rheumatoid factor RF-ET1, IGL c600_light_IGKV4-1_IGKJ4, and SELL), which are mostly associated with immunity, is accurate for diagnosis of autism.

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.

Dysregulation of immune system markers, gut microbiota and short-chain fatty acid production following prenatal alcohol exposure: A developmental perspective

Prenatal alcohol exposure (PAE) can severely impact fetal development, including alterations to the developing immune system. Immune perturbations, in tandem with gut dysbiosis, have been linked to brain and behavioral dysfunction, but this relationship is poorly understood in the context of PAE. This study takes an ontogenetic approach to evaluate PAE-induced alterations to brain and serum cytokine levels and both the composition and metabolic output of the gut microbiota. Using a well-established rat model of PAE, cytokine levels in the serum, prefrontal cortex, amygdala, and hypothalamus as well as gut microbiota composition and short-chain fatty acid (SCFA) levels were assessed at three postnatal (P) timepoints: P8 (infancy), P22 (weaning), and P38 (adolescence). Male PAE rats had increased cytokine levels in the amygdala and hypothalamus, but not prefrontal cortex, at P8. This altered neuroimmune function was not seen in the PAE females. The effect of PAE on central cytokine levels was reduced at P22/38, the same age at which PAE-induced alterations in serum cytokine levels emerge in both sexes. PAE reduced bacterial diversity in both sexes at P8, but only in females at P38, where a PAE-induced unique community composition emerged. Both sexes had alterations to specific bacterial taxa (e.g., Firmicutes), some of which are important in producing the SCFA butyric acid, which was decreased in PAE animals at P22. These results demonstrate that PAE leads to sex- and age-specific alterations in immune function, gut microbiota and SCFA production, highlighting the need to consider both age and sex in future work.

Regional skull translocator protein elevation in autistic adults detected by PET-MRI

Immune processes have been implicated in the pathophysiology of autism spectrum disorder (ASD). Brain borders, such as the skull, have recently been highlighted as sites where neuro-immune interactions occur with key consequences for brain immunity. Translocator protein (TSPO), a mitochondrial protein involved in immune functions, was measured in the skull using [11C]PBR28 positron emission tomography-magnetic resonance imaging (PET-MRI) in 38 autistic adults (26 males, 12 females) and 29 age-and sex-matched healthy controls (19 males, 10 females). [11C]PBR28 uptake relative to a pseudo-reference region assessed using standardized uptake value ratio (SUVR) revealed elevated TSPO in autistic adults in frontal and temporal skull. We did not observe an association between [11C]PBR28 uptake in total or regional skull areas and autism symptom severity. C-reactive protein levels were positively associated with [11C]PBR28 uptake in the total skull across participants. Lastly, [11C]PBR28 uptake in the total skull was stable across a 4-month period. This work indicates regional TSPO elevations in the skull in autistic adults, which may suggest immune involvement.

Peripheral Blood Monocytes as Biomarkers of Neurodevelopmental Disorders: A Systematic Review and Meta-Analysis

Accumulating evidence implicates immune dysregulation and chronic inflammation in neurodevelopmental disorders (NDDs), often manifesting as abnormal alterations in peripheral blood immune cell levels. The mononuclear phagocyte system, including monocytes and microglia, has been increasingly recognized for its involvement in the pathogenesis of NDDs. However, due to inconsistent findings in the literature, whether monocytes can serve as a reliable biomarker for NDDs remains controversial. To address this issue, we conducted a systematic review and meta-analysis of studies examining monocyte counts in NDD individuals. A comprehensive search was conducted across PubMed, Web of Science, and Scopus databases. Variables extracted for analysis encompassed the author's name, year of study, sample size, patient's age, type of disease, mean, standard deviation of monocytes and sex ratio. A total of 2503 articles were found by searching the three databases. After removed duplicates and screening titles, abstracts, and full texts, 17 articles met the inclusion criteria, and 20 independent studies were included in the meta-analysis. The results indicated significantly increased monocyte counts in 5 type NDDs compared to Typical Development (TD) groups (g = 0.36, 95%CI [0.23, 0.49]). Subgroup analyses revealed no significant differences in monocyte counts across different NDD types, gender, or age. These findings suggest that aberrant alterations in monocyte counts are common in NDD cases, indicating their potential as biomarkers for these conditions. Future research should further investigate the role of monocyte in understanding the mechanisms, early detection, and clinical diagnosis of NDDs.

One cell to rule them all: Immune regulation of the brain in autism spectrum disorder

For 80 years there has been a link between autism and immune activation. Studies point to dysfunction in immune responses in peripheral blood, gut mucosa, and brain. Human postmortem brain studies in autism show increased differential expression of inflammatory immune genes, increased pro-inflammatory cytokine levels, and glial activation. Immune cells in the brain are comprised of both tissue-resident cells and those recruited from the blood. This includes regulatory T cells (Tregs) that foster immune tolerance and tissue repair. Tregs reduce microglial reactivity, assist in regenerative and reparative processes, and promote differentiation of myelin-producing oligodendrocytes in the brain, thus modulating white matter development. Neuroinflammation may be a universal autism phenotype independent of the underlying etiology that can be controlled by Tregs promoting homeostasis, microglia and oligodendrocyte function, and white matter development.

Retrotransposon: an insight into neurological disorders from perspectives of neurodevelopment and aging

Neurological disorders present considerable challenges in diagnosis and treatment due to their complex and diverse etiology. Retrotransposons are a type of mobile genetic element that are increasingly revealed to play a role in these diseases. This review provides a detailed overview of recent developments in the study of retrotransposons in neurodevelopment, neuroaging, and neurological diseases. Retrotransposons, including long interspersed nuclear elements-1, Alu, SINE-VNTR-Alu, and endogenous retrovirus, play important regulatory roles in the development and aging of the nervous system. They have also been implicated in the pathological processes of several neurological diseases, including Alzheimer's disease, X-linked dystonia-parkinsonism, amyotrophic lateral sclerosis, autism spectrum disorder, and schizophrenia. Retrotransposons provide a new perspective for understanding the molecular mechanisms underlying neurological diseases and provide insights into diagnostic and therapeutic strategies of these diseases.

What are the levels and interactions of neuroligin-1, neuroligin-3, and inflammatory cytokines (IL-6, IL-8) in children diagnosed with autism spectrum disorder?

Autism spectrum disorder (ASD) is characterized by deficits in social interaction, restricted interests, and repetitive behaviors. Several genes, including synaptic proteins and environmental risk factors, play a role in the etiology of autism. We aimed to evaluate the relationship between neuroligin-1 (NLGN-1) and neuroligin-3 (NLGN-3) levels, which are neuronal cell adhesion molecules (CAMs), and inflammatory cytokine (IL-6, IL-8) levels with disease severity and symptom clusters and with each other in children with ASD. Eighty children diagnosed with autism who met the inclusion criteria and sixty-five typically developing children matched for age and sex were included in the study. The children were evaluated psychiatrically through a semi-structured interview, DSM-5 criteria, the Childhood Autism Rating Scale (CARS), and the Social Communication Questionnaire (SCQ). IL-6, IL-8, NLGN-1, and NLGN-3 levels were analyzed in peripheral serum samples using human ELISA kits. IL-8 and NLGN-3 levels were higher in the autism group (p < 0.001, p < 0.001). IL-6 was positively related to CARS and SCQ total scores (p = 0.021, p = 0.040, respectively). IL-8, and NLGN-3 were positively associated with the all subtests of the SCQ and the SCQ total score (all p values <0.001). NLGN-1, NLGN-3, and inflammatory cytokine (IL-6, IL-8) levels were positively correlated (all p values <0.001). Neuroligins play a central role in the brain's ability to process information and maybe a key target in the pathogenesis of ASD. Further research is needed to determine whether, to what extent and how neuronal CAMs and immunity modulate each other and whether this contributes to ASD pathogenesis. Future studies should also be expanded to investigate the influence of variables such as oxidative stress, metalloproteases responsible for ectodomain shedding, or epigenetic regulation.

Lung-specific SFTPC mutations lead to neurodevelopmental disorders with neuroinflammation

Neurodevelopmental disorders (NDDs) are characterized by diverse genetic underpinnings and abnormalities in the structure and function of the central nervous system. While the lung-specific SFTPC gene is critical for pulmonary development and homeostasis, its potential involvement in NDDs has not been previously explored. In this study, we identified compound heterozygous variants of SFTPC in two children diagnosed with NDDs, inherited from carrier parents. Bioinformatic analyses predicted these variants to be deleterious, and patient blood samples confirmed reduced SFTPC protein levels. To investigate the functional impact of these mutations, we generated a Sftpc-knock-in (Sftpc-KI) mouse model carrying the defective alleles. The Sftpc-KI mice exhibited significantly reduced Sftpc expression in both lung and blood samples. Remarkably, despite its lung-specific expression, Sftpc-KI mice displayed pronounced impairments in neurobehavioral performance. Proteomic analyses of the Sftpc-KI mouse brain revealed dysregulated proteins associated with neuroinflammation. Furthermore, primary microglial cells isolated from these mice exhibited heightened expression of M1 activation markers, indicating aberrant microglial activation. Our findings uncover a previously unrecognized connection between lung-specific SFTPC dysfunction and neurodevelopmental disorders, suggesting the existence of a novel brain-lung axis and opening new avenues for research into the molecular mechanisms underlying NDDs.

The kinase RIPK3 promotes neuronal survival by suppressing excitatory neurotransmission during central nervous system viral infection

While recent work has identified roles for immune mediators in regulating neural activity, how innate immune signaling within neurons influences neurotransmission remains poorly understood. Emerging evidence suggests that the modulation of neurotransmission may serve important roles in host protection during infection of the central nervous system. Here, we showed that receptor-interacting protein kinase-3 (RIPK3) preserved neuronal survival during flavivirus infection through the suppression of excitatory neurotransmission. These effects occurred independently of the traditional functions of RIPK3 in promoting necroptosis and inflammatory transcription. Instead, RIPK3 promoted phosphorylation of the neuronal regulatory kinase calcium/calmodulin-dependent protein kinase II (CaMKII), which in turn activated the transcription factor cyclic AMP response element-binding protein (CREB) to drive a neuroprotective transcriptional program and suppress deleterious glutamatergic signaling. These findings identify an unexpected function for a canonical cell death protein in promoting neuronal survival during viral infection through the modulation of neuronal activity, highlighting mechanisms of neuroimmune crosstalk.

Autologous cord blood vs individualized supplements in autistic spectrum disorder: CORDUS study results

BACKGROUND

Cellular therapies have started an important new therapeutic direction in autistic spectrum disorder (ASD), and the ample diversity of ASD pathophysiology and the different types of cell therapies prompt an equally ample effort to employ clinical studies for studying the ASD causes and cell therapies. Stem cells have yielded so far mixed results in clinical trials, and at patient level the results varied from impressive to no improvement. In this context we have administered autologous cord blood (ACB) and a non-placebo, material intervention represented by an individualized combination of supplements (ICS) to ASD children.

AIM

To compare the efficacy of ACB vs ICS and find markers correlated with the child's progress in order to better predict ACB efficacy.

METHODS

CORDUS clinical study is a crossover study in which both oral ICS and intravenous ACB were sequentially administered to 56 children; ACB was infused as an inpatient procedure. Treatment efficacy was evaluated pre-treatment and post-treatment at 6 months by an independent psychotherapist with Autism Treatment Evaluation Checklist, Quantitative Checklist for Autism in Toddlers and a 16-item comparative table score, after interviewing the children’s parents and therapists. Before and after each intervention participants had a set of blood tests including inflammatory, metabolic and oxidative markers, and the neuronal specific enolase.

RESULTS

No serious adverse reactions were noted during and after cord blood or supplement administration. ACB improved evaluation scores in 78% of children with age 3–7-years (n = 28), but was much less effective in kids older than 8 years or with body weight of more than 35 kg (n = 28; only 11% of children improved scores). ICS yielded better results than ACB in 5 cases out of 28, while in 23 kids ACB brought more improvement than ICS (P < 0.05); high initial levels of inflammation and ferritin were associated with no improvement. Ample individual differences were noted in children's progress, and statistically significant improvements were seen after ACB on areas such as verbalization and social interaction, but not on irritability or aggressive behavior.

CONCLUSION

ACB has superior efficacy to ICS in ASD; high inflammation, ferritin, age and body weight predict less improvement; more clinical studies are needed for studying ACB efficacy in ASD.

Profiling of activated monocyte populations in autism and associations with increased severity and comorbid behaviors

Immune dysfunction in autism spectrum disorder (ASD) has been widely reported and is associated with increased impairments in social interactions, communication, repetitive behaviors, anxiety and gastrointestinal problems. Several lines of evidence point towards increased activation of the innate immune system including activation of microglia, increases in innate inflammatory cytokines/chemokines in blood, brain tissue and CSF, activated dendritic cells and macrophages, and abnormal peripheral monocyte cell function. Monocytes are major players in innate immunity and have important functions in the phagocytosis of pathogens or debris, immune defense and cytokine/chemokine production. However, little is known about the frequencies of different circulating monocytes populations in ASD compared with similarly aged typically developing (TD) controls. In this study, the profile of circulating monocytes exhibiting different markers of activation were assessed in 77 children with ASD, and 49 TD controls who were enrolled as part of the Autism Phenome Project and were of a similar age, 2-4 years old. The frequencies of monocytes expressing the activation marker CD137 (4-1BB) were significantly increased in children with ASD and associated with greater behavioral impairments. In addition, although the frequencies of non-classical monocytes (CD14+CD16+) were not significantly different across groups, they were linked to worse behaviors in both the context of ASD and TD. Conversely classical monocytes were associated with better behavioral outcomes. These data further implicate monocytes and innate immune cells in the complex pathophysiology of ASD. Monocyte cells play key roles in modulating immune responses and differences in the activation profiles of these cells may result in immune dysfunction in children with ASD.

Research trends of inflammation in autism spectrum disorders: a bibliometric analysis

Background

Inflammation has been recognized as a significant factor in the pathophysiology of autism spectrum disorders (ASD), which have garnered increasing scholarly attention over the past few decades. This study aims to explore research trends related to inflammation and ASD through bibliometric analysis.

Method

A comprehensive literature search was conducted in the Web of Science Core Collection (WoSCC) on August 28, 2024. This study was restricted to literature published in English. The bibliometric analysis utilized VOSviewer, CiteSpace, and the R package "bibliometrix" to visualize collaborations, keyword co-occurrences, and emerging research trends.

Results

A total of 1,752 articles addressing inflammation and ASD were published, demonstrating a consistent upward trend in research output. The United States emerged as the country with the highest volume of publications. Saleh A. Bakheet was identified as the most prolific authors, significantly contributing to the literature with 54 publications. The University of California System was recognized as the most productive institution in this area of study. The journal of Brain Behavior and Immunity was noted as a prominent venue for publication in this field, exhibiting high citation metrics that reflect its considerable influence. The keyword "children" was the most frequently occurring term, with other significant terms including "oxidative stress" and "brain." The keyword burst analysis revealed notable periods of increased research focus on topics such as "inflammatory bowel disease," "cytokine production," "neurodevelopmental disorders," and "microbiota."

Conclusion

This bibliometric analysis highlights the growing scholarly attention devoted to the relationship between inflammation and ASD. Significant contributions and emerging trends emphasize the pivotal role of neuroinflammation in ASD, indicating a necessity for further exploration in this domain.

Threshold effects of prenatal stress on striatal microglia and relevant behaviors

Prenatal stress, a risk factor for neurodevelopmental disorders (NDDs), leads to immune alterations, including offspring neuroimmune cells. Differences in offspring outcomes may arise from whether the extent of prenatal stress crosses "thresholds" for effects on specific outcomes. Therefore, we sought to determine offspring outcomes using models with different extents of prenatal stress. We focused on striatal outcomes, because of their relevance for NDDs. Pregnant CD1 mice were assigned to four groups (each: N=6): no stress ("NoS") or one of the following stressors administered three times daily: i.p. saline injections (low prenatal stress, LoS), Interleukin-6 injections as a component of prenatal stress (immune prenatal stress; ImS), or restraint stress + saline injections (high prenatal stress, HiS), embryonic day 12-18. In adult offspring, HiS altered striatal-dependent behavior across males and females, while ImS induced fewer behavioral changes, and LoS did not affect behavior. Adult striatal microglia morphologies were mostly unchanged across groups, with only HiS leading to altered striatal density of minimally ramified cells. However, embryonic striatal microglia were affected by all models of stress, albeit in distinct ways. The HiS model, and to a lesser extent LoS, also influenced immune components of the maternal-fetal interface: placental macrophages. In conclusion, high and immune stress affected adult striatal-dependent behavior, exceeding the threshold necessary for persistent impacts, but all stress models affected embryonic microglia, suggesting that early neuroimmune outcomes had a lower threshold for impacts. Distinct severities and aspects of prenatal stress may therefore underlie different outcomes relevant to NDDs.

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.

Identification of Bacterial Lipopolysaccharide-Associated Genes and Molecular Subtypes in Autism Spectrum Disorder

Background

Autism spectrum disorder (ASD) is a complex neurodevelopmental condition marked by diverse symptoms affecting social interaction, communication, and behavior. This research aims to explore bacterial lipopolysaccharide (LPS)- and immune-related (BLI) molecular subgroups in ASD to enhance understanding of the disorder.

Methods

We analyzed 89 control samples and 157 ASD samples from the GEO database, identifying BLI signatures using least absolute shrinkage and selection operator regression (LASSO) and logistic regression machine learning algorithms. A nomogram prediction model was developed based on these signatures, and we performed Gene Set Enrichment Analysis (GSEA), Gene Set Variation Analysis (GSVA), and immune cell infiltration analysis to assess the impact of BLI subtypes and their underlying mechanisms.

Results

Our findings revealed 17 differentially expressed BLI genes in children with ASD, with BLNK, MAPK8, PRKCQ, and TNFSF12 identified as potential biomarkers. The nomogram demonstrated high diagnostic accuracy for ASD. We delineated two distinct molecular subtypes (Cluster 1 and Cluster 2), with GSVA indicating that Cluster 2 showed upregulation of immune- and inflammation-related pathways. This cluster exhibited increased levels of antimicrobial agents, chemokines, cytokines, and TNF family cytokines, alongside activation of bacterial lipoprotein-related pathways. A significant correlation was found between these pathways and distinct immune cell subtypes, suggesting a potential mechanism for neuroinflammation and immune cell infiltration in ASD.

Conclusion

Our research highlights the role of BLI-associated genes in the immune responses of individuals with ASD, indicating their contribution to the disorder's typification. The interplay between bacterial components, genetic predisposition, and immune dysregulation offers new insights for understanding ASD and developing personalized interventions.

EEG Abnormalities and Phenotypic Correlates in Preschoolers with Autism Spectrum Disorder: A Single-Center Study

Background: The literature suggests the existence of an association between autism spectrum disorders (ASDs) and subclinical electroencephalographic abnormalities (SEAs), which show a heterogeneous prevalence rate (12.5-60.7%) within the pediatric ASD population. The aim of this study was to investigate the EEG findings in a cohort of ASD preschoolers and their correlation with the phenotypic characteristics. Methods: We retrospectively reviewed data on 141 ASD preschoolers evaluated in a tertiary care university hospital over the period 2008-2018. All participants underwent at least one standard polygraphic electroencephalogram (EEG) and a clinical multidisciplinary assessment with standardized instruments. Results: 77 patients (55%) showed SEAs, which were mainly represented by epileptiform discharges (p < 0.00001), especially focal and multifocal (p = 0.010). Abnormal EEG (p = 0.035) and epileptiform discharges (p = 0.014) were associated with seizure onset and were predominant in sleep (p < 0.00001). Patients with abnormal tracing (p = 0.031) and slow abnormalities (p < 0.001) were significantly younger. ASD severity was not found to be correlated with EEG results, which showed a potential, albeit non-significant, association with some psychometric parameters. Very similar results were found when patients were divided according to sex. Conclusions: EEG abnormalities appear to correlate more with ASD internalizing, externalizing and emotional comorbidities, rather than with ASD core symptoms; larger samples are needed to further investigate this association.

[Assessment of developmental neurotoxicity of pharmaceuticals using zebrafish behavior]

Pharmaceuticals used for pregnant women must be safe for the babies while therapeutic to the mothers. To ensure the safety of drugs, developmental neurotoxicity should be evaluated although it is currently not a mandatory requirement in the US and Europe at the regulatory level. Organisation for Economic Co-operation and Development (OECD) has constituted the test guideline (TG426) to assess developmental neurotoxicity. TG426 requires various assessments using animals (assuming rats), including the brain weight, neuropathology, locomotion, sensorimotor function, and learning ability of dams from the mother treated with the chemical during pregnancy. Due to the huge burden of the cost, time, and labor, the number of chemicals evaluated for developmental neurotoxicity by TG426 remains around 200. To boost the pace of the assessment, OCED has constituted a novel guideline (No. 377) adopting in vitro test batteries. OCED has also evaluated the utility of the neurobehavior of zebrafish larvae in the assessment of developmental neurotoxicity. In this review, I focus on valproic acid, a therapeutic drug to treat epilepsy and bipolar disorder and a well-known developmental neurotoxicant, and summarize the studies using zebrafish neurobehavior to assess the developmental neurotoxicity of valproic acid. The utility and validity of zebrafish neurobehavior for developmental neurotoxicity testing are discussed by comparing the findings from rodents and humans.

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.

Targeting S100A9 attenuates social dysfunction by modulating neuroinflammation and myelination in a mouse model of autism

Growing evidence supports a role for dysregulated neuroinflammation in autism. However, the underlying mechanisms of microglia-evoked neuroinflammation in the development of autistic phenotypes have not been elucidated. This study aimed to investigate the role and underlying mechanisms of microglial S100 calcium-binding protein A9 (S100A9) in autistic phenotypes. We utilized the BTBR T + tf/J (BTBR) mouse, a reliable preclinical model for autism that displays core behavioral features of autism as well as persistent immune dysregulation. A combination of behavioral, pharmacological, immunological, genetic, molecular, and transcriptomics approaches were used to uncover the potential role of S100A9 in autism. Significant overexpression of microglial S100A9 was observed in the hippocampus of BTBR mice. BTBR mice displayed decreased social communication and increased repetitive behaviors compared to C57BL/6 mice. Interestingly, the above social dysfunction was attenuated by a pharmacological inhibitor of S100A9, accompanied by a significant reduction in the activated microglia morphological phenotype, inflammatory receptors, and proinflammatory cytokines. Notably, S100A9 inhibition decreased c-Fos+ cells and promoted myelination in the cornu ammonis 3 of BTBR mice. Furthermore, the promyelinating compound administration ameliorated the autism-relevant behaviors in BTBR mice. Our findings indicate that microglia-derived S100A9 triggers the neuroinflammation cascade, myelination deficits, and social dysfunction. Targeting S100A9 could, therefore, be a promising therapeutic strategy for neuroinflammation-related neurodevelopmental disorders.

Bi-allelic NRXN1α deletion in microglia derived from iPSC of an autistic patient increases interleukin-6 production and impairs supporting function on neuronal networking

Autism spectrum disorder (ASD) is a set of heterogeneous neurodevelopmental conditions, with a highly diverse genetic hereditary component, including altered neuronal circuits, that has an impact on communication skills and behaviours of the affected individuals. Beside the recognised role of neuronal alterations, perturbations of microglia and the associated neuroinflammatory processes have emerged as credible contributors to aetiology and physiopathology of ASD. Mutations in NRXN1, a member of the neurexin family of cell-surface receptors that bind neuroligin, have been associated to ASD. NRXN1 is known to be expressed by neurons where it facilitates synaptic contacts, but it has also been identified in glial cells including microglia. Asserting the impact of ASD-related genes on neuronal versus microglia functions has been challenging. Here, we present an ASD subject-derived induced pluripotent stem cells (iPSC)-based in vitro system to characterise the effects of the ASD-associated NRXN1 gene deletion on neurons and microglia, as well as on the ability of microglia to support neuronal circuit formation and function. Using this approach, we demonstrated that NRXN1 deletion, impacting on the expression of the alpha isoform (NRXN1α), in microglia leads to microglial alterations and release of IL6, a pro-inflammatory interleukin associated with ASD. Moreover, microglia bearing the NRXN1α-deletion, lost the ability to support the formation of functional neuronal networks. The use of recombinant IL6 protein on control microglia-neuron co-cultures or neutralizing antibody to IL6 on their NRXN1α-deficient counterparts, supported a direct contribution of IL6 to the observed neuronal phenotype. Altogether, our data suggest that, in addition to neurons, microglia are also negatively affected by NRXN1α-deletion, and this significantly contributes to the observed neuronal circuit aberrations.

Ontogenetic Neuroimmune Changes Following Prenatal Alcohol Exposure: Implications for Neurobehavioral Function

This chapter reviews the enduring effects of prenatal alcohol exposure (PAE) on neuroimmune function across the lifespan, including discussion of associated neurobehavioral alterations. Alcohol has potent teratogenic effects, with a large body of work linking PAE to perturbations in neuroimmune function. These PAE-related neuroimmune disturbances may have downstream effects on neurobehavioral function given the critical role of the neuroimmune system in central nervous system development. The neuroimmune system matures over time, playing distinct roles depending on the developmental processes occurring within that maturational stage. This chapter thus takes an ontogenetic approach to understanding how PAE induces unique neuroimmune changes across the lifespan, beginning with a review of changes in early life before moving into adolescence and ending in adulthood. The focus will be on work utilizing rodent models, which allow for more tightly controlled conditions than are possible in human research. The chapter concludes with a discussion of possible mechanisms underlying the developmental changes in neuroimmune function following PAE, with a specific focus on the role of the gut microbiota.

Toward a better understanding of T cell dysregulation in autism: An integrative review

Autism spectrum disorder (ASD) is a highly heterogeneous disorder characterized by impairments in social, communicative, and restrictive behaviors. Over the past 20 years, research has highlighted the role of the immune system in regulating neurodevelopment and behavior. In ASD, immune abnormalities are frequently observed, such as elevations in pro-inflammatory cytokines, alterations in immune cell frequencies, and dysregulated mechanisms of immune suppression. The adaptive immune system - the branch of the immune system conferring cellular immunity - may be involved in the etiology of ASD. Specifically, dysregulated T cell activity, characterized by altered cellular function and increased cytokine release, presence of inflammatory phenotypes and altered cellular signaling, has been consistently observed in several studies across multiple laboratories and geographic regions. Similarly, mechanisms regulating their activation are also disrupted. T cells at homeostasis coordinate the healthy development of the central nervous system (CNS) during early prenatal and postnatal development, and aid in CNS maintenance into adulthood. Thus, T cell dysregulation may play a role in neurodevelopment and the behavioral and cognitive manifestations observed in ASD. Outside of the CNS, aberrant T cell activity may also be responsible for the increased frequency of immune based conditions in the ASD population, such as allergies, gut inflammation and autoimmunity. In this review, we will discuss the current understanding of T cell biology in ASD and speculate on mechanisms behind their dysregulation. This review also evaluates how aberrant T cell biology affects gastrointestinal issues and behavior in the context of ASD.

A Wonderful Journey: The Diverse Roles of Adenosine Deaminase Action on RNA 1 (ADAR1) in Central Nervous System Diseases

BACKGROUND

Adenosine deaminase action on RNA 1 (ADAR1) can convert the adenosine in double-stranded RNA (dsRNA) molecules into inosine in a process known as A-to-I RNA editing. ADAR1 regulates gene expression output by interacting with RNA and other proteins; plays important roles in development, including growth; and is linked to innate immunity, tumors, and central nervous system (CNS) diseases.

RESULTS

In recent years, the role of ADAR1 in tumors has been widely discussed, but its role in CNS diseases has not been reviewed. It is worth noting that recent studies have shown ADAR1 has great potential in the treatment of neurodegenerative diseases, but the mechanisms are still unclear. Therefore, it is necessary to elaborate on the role of ADAR1 in CNS diseases.

CONCLUSIONS

Here, we focus on the effects and mechanisms of ADAR1 on CNS diseases such as Aicardi-AicardiGoutières syndrome, Alzheimer's disease, Parkinson's disease, glioblastoma, epilepsy, amyotrophic lateral sclerosis, and autism. We also evaluate the impact of ADAR1-based treatment strategies on these diseases, with a particular focus on the development and treatment strategies of new technologies such as microRNAs, nanotechnology, gene editing, and stem cell therapy. We hope to provide new directions and insights for the future development of ADAR1 gene editing technology in brain science and the treatment of CNS diseases.

Lipopolysaccharide induces neuroinflammation in a valproic acid male model of autism

BACKGROUND

Autism spectrum disorders (ASD) are characterized by social skill deficits and behavior impairments. Exposure to valproic acid (VPA) has been linked to ASD in humans and ASD-like behaviors in rodents. Clinical evidence suggests that immunological damage can worsen ASD symptoms in humans.

OBJECTIVE

This study aimed to investigate the potential of lipopolysaccharide (LPS) to induce neuroinflammation in a VPA-induced autism male model.

MATERIALS

and methods: Pregnant Sprague Dawley rats were injected with 500 mg/kg of VPA on gestational day 12.5 to create an ASD rat model in their offspring. Male offspring from VPA-injected group received 10 mg/kg of LPS on postnatal day 20. Immunohistochemistry, western blotting, and immunofluorescence were used to assess the expression of NF-κB signaling pathway-related proteins and microglia in the prefrontal cortex and hippocampus. Gene Ontology and pathway enrichment analyses were conducted to predict the function of key synaptic proteins, which were further validated through real-time polymerase chain reaction analysis.

RESULTS

The results showed that VPA exposure led to increased locomotor activity, social impairment, and repetitive behaviors in male rats. NF-κB signaling pathway-related proteins were upregulated, and microglial numbers were elevated in the VPA-induced group. Furthermore, synaptic dysfunction was observed in the brains of offspring exposed to VPA. Importantly, LPS administration exacerbated autism-related behaviors in VPA-exposed male rats by promoting NF-κB signaling pathway activation, increasing microglial numbers, and downregulating key synaptic proteins.

CONCLUSIONS

This study not only contributed to understanding the importance of the NF-κB signaling pathway, microglia, and synaptic proteins in the progression of ASD, but also identified that LPS induces neuroinflammation in a valproic acid-induced male model of autism.

Causal Relationship between Attention-Deficit Hyperactivity Disorder and Autism Spectrum Disorder: A Two-Sample Mendelian Randomization

Aims/Background Despite the exponential increase in the incidence rate of Autism spectrum disorder (ASD), effective therapies for the disorder are still limited. According to vast clinical observations, the pathogeneses of ASD and Attention-deficit hyperactivity disorder (ADHD) share a great deal of similarities. This serves as a prompt to investigate, in this study, whether patients with ADHD are at a higher risk for ASD, which is significant for disease prevention. Methods Data concerning ADHD as the exposure variable and ASD as the outcome variable were collected from the publicly available Integrative Epidemiology Unit Open GWAS project (IEU GWAS) database. After screening the instrumental variables (IVs), statistical analysis was performed using the TwoSampleMR package of version R4.3.1, and sensitivity testing was conducted to evaluate the stability and reliability of the results. Results After screening the Single nucleotide polymorphisms (SNPs) through the calculation of F-value and Mendelian randomization (MR) Pleiotropy RESidual Sum and Outlier test (MR-PRESSO), seven SNPs that satisfied the three major assumptions of Mendelian randomization were selected as IVs and could be used in place of ADHD in exploring the aforementioned causal relationship. The Odds ratio (OR) for the random-effect Inverse-variance weighted (IVW) method was 1.31 (95% Confidence interval [CI]: 1.14-1.52; p = 0.0001). A similar trend was observed for the Weighted median estimator (WME) method, with an OR of 1.37 (wider 95% CI: 1.15-1.64; p = 0.0005). Conclusion This study includes the pooled data on ADHD and ASD from the IEU GWAS public database, and there is sufficient evidence that patients with ADHD have a higher risk of ASD.

Vasostatin-1 restores autistic disorders in an idiopathic autism model (BTBR T+ Itpr3tf/J mice) by decreasing hippocampal neuroinflammation

Chromogranin A (CgA), a ∼ 49 kDa acidic secretory protein, is ubiquitously distributed in endocrine and neuroendocrine cells and neurons. As a propeptide, CgA is proteolytically cleaved to generate several peptides of biological importance, including pancreastatin (PST: hCgA250-301), Vasostatin 1 (VS1: hCgA1-76), and catestatin (CST: CgA 352-372). VS1 represents the most conserved fragment of CgA. A 20 amino acid domain within VS1 (CgA 47-66) exhibits potent antimicrobial and anti-inflammatory activities. Autism is known to be associated with inflammation. Therefore, we seek to test the hypothesis that VS1 modulates autism behaviors by reducing inflammation in the hippocampus. Treatment of C57BL/6 (B6) and BTBR (a mouse model of idiopathic autism) mice with VS1 revealed the following: BTBR mice showed a significant decrease in chamber time in the presence of a stranger or a novel object. Treatment with VS1 significantly increased chamber time in both cases, underscoring a crucial role for VS1 in improving behavioral deficits in BTBR mice. In contrast to chamber time, sniffing time in BTBR mice in the presence of a stranger was less compared to B6 control mice. VS1 did not improve this latter parameter. Surprisingly, sniffing time in BTBR mice in the presence of a novel object was comparable with B6 mice. Proinflammatory cytokines such as IL-6 and IL-1b, as well as other inflammatory markers, were elevated in BTBR mice, which were dramatically reduced after supplementation with VS1. Interestingly, even Beclin-1/p62, pAKT/AKT, and p-p70-S6K/p70-S6K ratios were notably reduced by VS1. We conclude that VS1 plays a crucial role in restoring autistic spectrum disorders (ASD) plausibly by attenuating neuroinflammation.

The intersection of inflammation and DNA damage as a novel axis underlying the pathogenesis of autism spectrum disorders

Autism spectrum disorders (ASD) affects 1 in 36 children and is characterized by repetitive behaviors and difficulties in social interactions and social communication. The etiology of ASD is extremely heterogeneous, with a large number of ASD cases that are of unknown or complex etiology, which suggests the potential contribution of epigenetic risk factors. In particular, epidemiological and animal model studies suggest that inflammation during pregnancy could lead to an increased risk of ASD in the offspring. However, the molecular mechanisms that contribute to ASD pathogenesis in relation to maternal inflammation during pregnancy in humans are underexplored. Several pro-inflammatory cytokines have been associated with increased autistic-like behaviors in animal models of maternal immune activation, including IL-17A. Using a combination of ASD patient lymphocytes and stem cell-derived human neurons exposed to IL-17A we discovered a shared molecular signature that highlights a metabolic and translational node that could lead to altered neuronal excitability. Further, our work on human neurons brings forward the possibility that defects in the DNA damage response could be underlying the effect of IL-17A on human excitatory neurons, linking exacerbated unrepaired DNA damage to the pathogenicity of maternal inflammation in connection to ASD.

An Update on Microbial Interventions in Autism Spectrum Disorder with Gastrointestinal Symptoms

In the United States, autism spectrum disorder (ASD) affects 1 in 33 children and is characterized by atypical social interactions, communication difficulties, and intense, restricted interests. Microbial dysbiosis in the gastrointestinal (GI) tract is frequently observed in individuals with ASD, potentially contributing to behavioral manifestations and correlating with worsening severity. Moreover, dysbiosis may contribute to the increased prevalence of GI comorbidities in the ASD population and exacerbate immune dysregulation, further worsening dysbiosis. Over the past 25 years, research on the impact of microbial manipulation on ASD outcomes has gained substantial interest. Various approaches to microbial manipulation have been preclinically and clinically tested, including antibiotic treatment, dietary modifications, prebiotics, probiotics, and fecal microbiota transplantation. Each method has shown varying degrees of success in reducing the severity of ASD behaviors and/or GI symptoms and varying long-term efficacy. In this review, we discuss these microbiome manipulation methods and their outcomes. We also discuss potential microbiome manipulation early in life, as this is a critical period for neurodevelopment.

Maternal separation alters peripheral immune responses associated with IFN-γ and OT in mice

The co-evolution of social behavior and the immune system plays a critical role in individuals' adaptation to their environment. However, also need for further research on the key molecules that co-regulate social behavior and immunity. This study focused on neonatal mice that were separated from their mothers for 4 hours per day between the 6th and 16th day after birth. The results showed that these mice had lower plasma levels of IFN-γ and oxytocin, but higher levels of plasma glucocorticoids (GC), then impacting their social abilities. Additionally, maternal separation led to decreased levels of BDNF, IGF2, and CREB mRNAs in the hippocampus, while levels in the prefrontal cortex (PFC) remained unaffected. Maternal separation also resulted in increased levels of oxytocin and CRH mRNA in the hypothalamus, as well as an increase in CD45+ lymphocyte subsets in the meninges and choroid plexus (CP), with CD8+ lymphocytes in meninges and CD4+ lymphocytes in CP showing an increase. In IFN-γ-/- mice, a decrease in social preference was observed alongside lower plasma oxytocin levels. Moreover, IFN-γ-/- mice exhibited reduced numbers of oxytocin neurons in the paraventricular nucleus of the paraventricular nucleus of hypothalamus (PVN), decreased BDNF levels in the PFC and hippocampus, and alterations in CD45+ lymphocytes in CP and meninges, with an increase in CD8+ lymphocytes in meninges and CD4+ lymphocytes in CP. These findings highlight the immunological impact of social stress on IFN-γ regulation, suggesting that the immunomodulatory molecule IFN-γ may influence social behavior by affecting synaptic efficiency in brain regions such as the hippocampus and PFC, which are linked to oxytocin in the PVN.

NLRP3 inflammasome-mitochondrion loop in autism spectrum disorder

Autism spectrum disorder (ASD) is a neurodevelopmental disorder characterized by deficits in social communication and the presence of restricted interests and repetitive behavior. To date, no single cause has been demonstrated but both genetic and environmental factors are believed to be involved in abnormal brain development. In recent years, immunological and mitochondrial dysfunctions acquired particular interest in the study of the molecular mechanisms underlying the pathophysiology of ASD. For this reason, our study focused on evaluating the mitochondrial component and activation of the NLRP3 inflammasome, a critical player of the innate immune system. The assembly of NLRP3 with ASC mediates activation of Caspase-1, which in turn, by proteolytic cleavage, activates Gasdermin D and the proinflammatory cytokines IL-1β/IL-18 with their subsequent secretion. Using primary fibroblasts of autistic and control patients we studied basal and stimulated conditions. Specifically, LPS and ATP were used to activate the NLRP3 inflammasome and MCC950 for its inhibition. In addition, FCCP was used as a mitochondrial stressor and MitoTEMPO as a scavenger of mitochondrial ROS. Our results showed a hyperactivation of NLRP3 inflammasome in ASDs, as evidenced by the co-localization of the two main components, NLRP3 and ASC, by the higher levels of ASC specks, oligomers and dimers and by the increased amounts of active Caspase-1 and IL-1β. In addition, increased mitochondrial superoxide anion and reduced mitochondrial membrane potential were detected in ASD cells. These data are in accordance with the abnormal mitochondrial morphology evidenced by transmission electron microscopy analysis. Interestingly, NLRP3 inflammasome inhibition with MCC950 improved mitochondrial parameters, while the use of MitoTEMPO, in addition to decrease mitochondrial ROS production, was able to prevent NLRP3 inflammasome activation suggesting for the first time an abnormal bidirectional crosstalk between mitochondria and NLRP3 inflammasome in 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.

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.

Shared Genetic Determinants of Schizophrenia and Autism Spectrum Disorder Implicate Opposite Risk Patterns: A Genome-Wide Analysis of Common Variants

BACKGROUND AND HYPOTHESIS

The synaptic pruning hypothesis posits that schizophrenia (SCZ) and autism spectrum disorder (ASD) may represent opposite ends of neurodevelopmental disorders: individuals with ASD exhibit an overabundance of synapses and connections while SCZ was characterized by excessive pruning of synapses and a reduction. Given the strong genetic predisposition of both disorders, we propose a shared genetic component, with certain loci having differential regulatory impacts.

STUDY DESIGN

Genome-Wide single nucleotide polymorphism (SNP) data of European descent from SCZ (N cases = 53 386, N controls = 77 258) and ASD (N cases = 18 381, N controls = 27 969) were analyzed. We used genetic correlation, bivariate causal mixture model, conditional false discovery rate method, colocalization, Transcriptome-Wide Association Study (TWAS), and Phenome-Wide Association Study (PheWAS) to investigate the genetic overlap and gene expression pattern.

STUDY RESULTS

We found a positive genetic correlation between SCZ and ASD (rg = .26, SE = 0.01, P = 7.87e-14), with 11 genomic loci jointly influencing both conditions (conjFDR <0.05). Functional analysis highlights a significant enrichment of shared genes during early to mid-fetal developmental stages. A notable genetic region on chromosome 17q21.31 (lead SNP rs2696609) showed strong evidence of colocalization (PP.H4.abf = 0.85). This SNP rs2696609 is linked to many imaging-derived brain phenotypes. TWAS indicated opposing gene expression patterns (primarily pseudogenes and long noncoding RNAs [lncRNAs]) for ASD and SCZ in the 17q21.31 region and some genes (LRRC37A4P, LINC02210, and DND1P1) exhibit considerable variation in the cerebellum across the lifespan.

CONCLUSIONS

Our findings support a shared genetic basis for SCZ and ASD. A common genetic variant, rs2696609, located in the Chr17q21.31 locus, may exert differential risk regulation on SCZ and ASD by altering brain structure. Future studies should focus on the role of pseudogenes, lncRNAs, and cerebellum in synaptic pruning and neurodevelopmental disorders.

Autism Spectrum Disorder Pathogenesis-A Cross-Sectional Literature Review Emphasizing Molecular Aspects

The etiology of autism spectrum disorder (ASD) has not yet been completely elucidated. Through time, multiple attempts have been made to uncover the causes of ASD. Different theories have been proposed, such as being caused by alterations in the gut-brain axis with an emphasis on gut dysbiosis, post-vaccine complications, and genetic or even autoimmune causes. In this review, we present data covering the main streams that focus on ASD etiology. Data collection occurred in many countries covering ethnically diverse subjects. Moreover, we aimed to show how the progress in genetic techniques influences the explanation of medical White Papers in the ASD area. There is no single evidence-based pathway that results in symptoms of ASD. Patient management has constantly only been symptomatic, and there is no ASD screening apart from symptom-based diagnosis and parent-mediated interventions. Multigene sequencing or epigenetic alterations hold promise in solving the disjointed molecular puzzle. Further research is needed, especially in the field of biogenetics and metabolomic aspects, because young children constitute the patient group most affected by ASD. In summary, to date, molecular research has confirmed multigene dysfunction as the causative factor of ASD, the multigene model with metabolomic influence would explain the heterogeneity in ASD, and it is proposed that ion channel dysfunction could play a core role in ASD pathogenesis.

Causal Metabolomic and Lipidomic Analysis of Circulating Plasma Metabolites in Autism: A Comprehensive Mendelian Randomization Study with Independent Cohort Validation

BACKGROUND

The increasing prevalence of autism spectrum disorder (ASD) highlights the need for objective diagnostic markers and a better understanding of its pathogenesis. Metabolic differences have been observed between individuals with and without ASD, but their causal relevance remains unclear.

METHODS

Bidirectional two-sample Mendelian randomization (MR) was used to assess causal associations between circulating plasma metabolites and ASD using large-scale genome-wide association study (GWAS) datasets-comprising 1091 metabolites, 309 ratios, and 179 lipids-and three European autism datasets (PGC 2015: n = 10,610 and 10,263; 2017: n = 46,351). Inverse-variance weighted (IVW) and weighted median methods were employed, along with robust sensitivity and power analyses followed by independent cohort validation.

RESULTS

Higher genetically predicted levels of sphingomyelin (SM) (d17:1/16:0) (OR, 1.129; 95% CI, 1.024-1.245; p = 0.015) were causally linked to increased ASD risk. Additionally, ASD children had higher plasma creatine/carnitine ratios. These MR findings were validated in an independent US autism cohort using machine learning analysis.

CONCLUSION

Utilizing large datasets, two MR approaches, robust sensitivity analyses, and independent validation, our novel findings provide evidence for the potential roles of metabolomics and circulating metabolites in ASD diagnosis and etiology.

Parasagittal dural volume correlates with cerebrospinal fluid volume and developmental delay in children with autism spectrum disorder

BACKGROUND

The parasagittal dura, a tissue that lines the walls of the superior sagittal sinus, acts as an active site for immune-surveillance, promotes the reabsorption of cerebrospinal fluid, and facilitates the removal of metabolic waste products from the brain. Cerebrospinal fluid is important for the distribution of growth factors that signal immature neurons to proliferate and migrate. Autism spectrum disorder is characterized by altered cerebrospinal fluid dynamics.

METHODS

In this retrospective study, we investigated potential correlations between parasagittal dura volume, brain structure volumes, and clinical severity scales in young children with autism spectrum disorder. We employed a semi-supervised two step pipeline to extract parasagittal dura volume from 3D-T2 Fluid Attenuated Inversion Recovery sequences, based on U-Net followed by manual refinement of the extracted parasagittal dura masks.

RESULTS

Here we show that the parasagittal dura volume does not change with age but is significantly correlated with cerebrospinal fluid (p-value = 0.002), extra-axial cerebrospinal fluid volume (p-value = 0.0003) and severity of developmental delay (p-value = 0.024).

CONCLUSIONS

These findings suggest that autism spectrum disorder children with severe developmental delay may have a maldeveloped parasagittal dura that potentially perturbs cerebrospinal fluid dynamics.

Protective effects of rosmarinic acid against autistic-like behaviors in a mouse model of maternal separation stress: behavioral and molecular amendments

Autism spectrum disorder (ASD) is a neurodevelopmental disorder with worldwide increasing incidence. Maternal separation (MS) stress at the beginning of life with its own neuroendocrine changes can provide the basis for development of ASD. Rosmarinic acid (RA) is a phenolic compound with a protective effect in neurodegenerative diseases. The aim of this study was to determine the effect of RA on autistic-like behaviors in maternally separated mice focusing on its possible effects on neuroimmune response and nitrite levels in the hippocampus. In this study, 40 mice were randomly divided into five groups of control (received normal saline (1 ml/kg)) and MS that were treated with normal saline (1 ml/kg) or doses of 1, 2, and 4 mg/kg RA, respectively, for 14 days. Three-chamber sociability, shuttle box, and marble burying tests were used to investigate autistic-like behaviors. Nitrite level and gene expression of inflammatory cytokines including TNF-α, IL-1β, TLR4, and iNOS were assessed in the hippocampus. The results showed that RA significantly increased the social preference and social novelty indexes, as well as attenuated impaired passive avoidance memory and the occurrence of repetitive and obsessive behaviors in the MS mice. RA reduced the nitrite level and gene expression of inflammatory cytokines in the hippocampus. RA, probably via attenuation of the nitrite level as well as of the neuroimmune response in the hippocampus, mitigated autistic-like behaviors in maternally separated mice.

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.

Treating reactivated EBV, HHV-6, HHV-7 infections in children with Autism Spectrum disorder associated with genetic folate cycle disruptions: Outcomes after Valacyclovir, Valganciclovir and Artesunate

Immune dysfunction causes the reactivation of herpesviruses in children with autism spectrum disorder (ASD) associated with the genetic folate cycle deficiency (GFCDs). The aim – to investigate the efficacy of valaciclovir, valganciclovir, and artesunate in reactivated Epstein-Barr virus (EBV), herpes virus type 6 (HHV-6) and herpes virus type 7 (HHV-7) infections in children with ASD. The treatment group consisted of 225 children aged 2 to 9 years who had GFCDs and ASD. The diagnosis of EBV, HHV-6, and HHV-7 reactivations was made by blood leukocyte PCR. Valacyclovir (500-1000 mg twice per day), valganciclovir (225-450mg twice per day), and artesunate (25-50mg twice a day) were prescribed for 3 months. The control group (no antiviral treatment) included 52 children who were comparable in age and diagnosis. Valacyclovir treatment achieved undetectable EBV DNA in 39% of cases. Valganciclovir and artesunate performed complete response rates of 47 and 62%, respectively (р<0.05; Z<Z0.05). HHV-6 DNA was undetectable in 29% of valacyclovir-treated patients. Valganciclovir and artesunate achieved complete response rates of 32 and 57%, respectively (p <0.05; Z<Z0.05). HHV-7 DNA was not detected in 24% of valacyclovir-treated patients, but in 35 and 44%, respectively (p <0.05, Z<Z0.05) in valganciclovir and artesunate groups. There was an association found between negative PCR results and normalized S-100 protein and neuron-specific enolase serum concentrations. Antiviral treatments disrupted the natural course of reactivated EBV, HHV-6, and HHV-7 infections in ASD children, exerting a neuroprotective effect, with artesunate being the most effective option and EBV - the most sensitive to antiviral drugs.

Immunological Biomarkers in Autism Spectrum Disorder: The Role of TNF-Alpha and Dependent Trends in Serum IL-6 and CXCL8

BACKGROUND

Autism spectrum disorder (ASD) has seen a rise in prevalence, and the immune system's role in brain development is increasingly recognized. This study investigates the relationship between immune dysregulation and ASD by examining serum concentrations of interleukin 6 (IL-6), interleukin 8 (CXCL8), and tumor necrosis factor alpha (TNF-alpha) in children.

METHODS

Serum samples from 45 children with ASD and 30 controls, aged 2 to 12 years, were analyzed using electrochemiluminescence, chemiluminescent microparticle immunoassay, and chemiluminescent immunoassay. ASD symptoms were assessed using the Autism Spectrum Rating Scale (ASRS) and Social Communication Questionnaire (SCQ).

RESULTS

No significant correlation was observed between CXCL8 levels and ASD. IL-6 levels showed a trend toward elevation in boys with ASD. TNF-alpha levels were significantly higher in children with ASD under 5 years compared to older children and controls, though no correlation with symptom severity was found.

CONCLUSIONS

TNF-alpha may be a potential biomarker for early ASD detection, especially in younger children. Further research on larger cohorts is needed to understand the role of immune dysregulation in ASD.

Associations of the immune system in aggression traits and the role of microglia as mediators

There is an important relationship between the immune system and aggressive behavior. Aggressive encounters acutely increase the levels of proinflammatory cytokines, and there are positive correlations between aggressive traits and peripheral proinflammatory cytokines. Endotoxin lipopolysaccharide (LPS) treatment, which results in peripheral immune activation, decreases aggressive behavior as one of the sickness behavioral symptoms. In contrast, certain brain infections and chronic interferon treatment are associated with increased aggression. Indeed, the effects of proinflammatory cytokines on the brain in aggressive behavior are bidirectional, depending on the type and dose of cytokine, target brain region, and type of aggression. Some studies have suggested that microglial activation and neuroinflammation influence intermale aggression in rodent models. In addition, pathological conditions as well as physiological levels of cytokines produced by microglia play an important role in social and aggressive behavior in adult animals. Furthermore, microglial function in early development is necessary for the establishment of the social brain and the expression of juvenile social behaviors, including play fighting. Overall, this review discusses the important link between the immune system and aggressive traits and the role of microglia as mediators of this link.

Clec7a Worsens Long-Term Outcomes after Ischemic Stroke by Aggravating Microglia-Mediated Synapse Elimination

Ischemic stroke (IS) is a leading cause of morbidity and mortality globally and triggers a series of reactions leading to primary and secondary brain injuries and permanent neurological deficits. Microglia in the central nervous system play dual roles in neuroprotection and responding to ischemic brain damage. Here, an IS model is employed to determine the involvement of microglia in phagocytosis at excitatory synapses. Additionally, the effects of pharmacological depletion of microglia are investigated on improving neurobehavioral outcomes and mitigating brain injury. RNA sequencing of microglia reveals an increase in phagocytosis-associated pathway activity and gene expression, and C-type lectin domain family 7 member A (Clec7a) is identified as a key regulator of this process. Manipulating microglial Clec7a expression can potentially regulate microglial phagocytosis of synapses, thereby preventing synaptic loss and improving neurobehavioral outcomes after IS. It is further demonstrat that microglial Clec7a interacts with neuronal myeloid differentiation protein 2 (MD2), a key molecule mediating poststroke neurological injury, and propose the novel hypothesis that MD2 is a ligand for microglial Clec7a. These findings suggest that microglial Clec7a plays a critical role in mediating synaptic phagocytosis in a mouse model of IS, suggesting that Clec7a may be a therapeutic target for IS.

Community-Engaged Research and the Use of Open Access ToxVal/ToxRef In Vivo Databases and New Approach Methodologies (NAM) to Address Human Health Risks From Environmental Contaminants

BACKGROUND

The paper analyzes opportunities for integrating Open access resources (Abstract Sifter, US EPA and NTP Toxicity Value and Toxicity Reference [ToxVal/ToxRefDB]) and New Approach Methodologies (NAM) integration into Community Engaged Research (CEnR).

METHODS

CompTox Chemicals Dashboard and Integrated Chemical Environment with in vivo ToxVal/ToxRef and NAMs (in vitro) databases are presented in three case studies to show how these resources could be used in Pilot Projects involving Community Engaged Research (CEnR) from the University of California, Davis, Environmental Health Sciences Center.

RESULTS

Case #1 developed a novel assay methodology for testing pesticide toxicity. Case #2 involved detection of water contaminants from wildfire ash and Case #3 involved contaminants on Tribal Lands. Abstract Sifter/ToxVal/ToxRefDB regulatory data and NAMs could be used to screen/prioritize risks from exposure to metals, PAHs and PFAS from wildfire ash leached into water and to investigate activities of environmental toxins (e.g., pesticides) on Tribal lands. Open access NAMs and computational tools can apply to detection of sensitive biological activities in potential or known adverse outcome pathways to predict points of departure (POD) for comparison with regulatory values for hazard identification. Open access Systematic Empirical Evaluation of Models or biomonitoring exposures are available for human subpopulations and can be used to determine bioactivity (POD) to exposure ratio to facilitate mitigation.

CONCLUSIONS

These resources help prioritize chemical toxicity and facilitate regulatory decisions and health protective policies that can aid stakeholders in deciding on needed research. Insights into exposure risks can aid environmental justice and health equity advocates.

Association between maternal multimorbidity and neurodevelopment of offspring: a prospective birth cohort study from the Japan Environment and Children's Study

OBJECTIVES

To investigate the association between multimorbidity during pregnancy and neurodevelopmental delay in offspring using data from a Japanese nationwide birth cohort study.

DESIGN

This study was a prospective birth cohort study.

SETTING

This study population included 104 059 fetal records who participated in The Japan Environment and Children's Study from 2011 to 2014.

PARTICIPANTS

Pregnant women whose children had undergone developmental testing were included in this analysis.

PRIMARY AND SECONDARY OUTCOME MEASURES

Neurodevelopment of offspring was assessed using the Japanese version of the Ages and Stages Questionnaire, third edition, comprising five developmental domains. The number of comorbidities among the pregnant women was categorised as zero, single disease or multimorbidity (two or more diseases). Maternal chronic conditions included in multimorbidity were defined as conditions with high prevalence among women of reproductive age. A multivariate logistic regression analysis was conducted to examine the association between multimorbidity in pregnant women and offspring development.

RESULTS

Pregnant women with multimorbidity, single disease and no disease accounted for 3.6%, 30.6% and 65.8%, respectively. The ORs for neurodevelopmental impairment during the follow-up period were similar for infants of mothers with no disease comorbidity and those with a single disease comorbidity. However, the ORs for neurodevelopmental impairment were significantly higher for children born to mothers with multimorbidity compared with those born to healthy mothers.

CONCLUSION

An association was observed between the number of comorbidities in pregnant women and developmental delay in offspring. Multimorbidity in pregnant women may be associated with neurodevelopmental delay in their offspring. Further research is required in this regard in many other regions of the world.

Prebiotic diet normalizes aberrant immune and behavioral phenotypes in a mouse model of autism spectrum disorder

Autism spectrum disorder (ASD) is a cluster of neurodevelopmental disorders characterized by deficits in communication and behavior. Increasing evidence suggests that the microbiota-gut-brain axis and the likely related immune imbalance may play a role in the development of this disorder. Gastrointestinal deficits and gut microbiota dysfunction have been linked to the development or severity of autistic behavior. Therefore, treatments that focus on specific diets may improve gastrointestinal function and aberrant behavior in individuals with ASD. In this study, we investigated whether a diet containing specific prebiotic fibers, namely, 3% galacto-oligosaccharide/fructo-oligosaccharide (GOS/FOS; 9:1), can mitigate the adverse effects of in utero exposure to valproic acid (VPA) in mice. Pregnant BALB/cByJ dams were injected with VPA (600 mg/kg, sc.) or phosphate-buffered saline (PBS) on gestational day 11 (G11). Male offspring were divided into four groups: (1) in utero PBS-exposed with a control diet, (2) in utero PBS-exposed with GOS/FOS diet, (3) in utero VPA-exposed with a control diet, and (4) in utero VPA-exposed with GOS/FOS diet. Dietary intervention started from birth and continued throughout the duration of the experiment. We showed that the prebiotic diet normalized VPA-induced alterations in male offspring, including restoration of key microbial taxa, intestinal permeability, peripheral immune homeostasis, reduction of neuroinflammation in the cerebellum, and impairments in social behavior and cognition in mice. Overall, our research provides valuable insights into the gut-brain axis involvement in ASD development. In addition, dietary interventions might correct the disbalance in gut microbiota and immune responses and, ultimately, might improve detrimental behavioral outcomes in ASD.

Bioenergetic and Inflammatory Alterations in Regressed and Non-Regressed Patients with Autism Spectrum Disorder

Autism spectrum disorder (ASD) is associated with multiple physiological abnormalities. Current laboratory and clinical evidence most commonly report mitochondrial dysfunction, oxidative stress, and immunological imbalance in almost every cell type of the body. The present work aims to evaluate oxygen consumption rate (OCR), extracellular acidification rate (ECAR), and inflammation-related molecules such as Cyclooxygenase-2 (COX-2), chitinase 3-like protein 1 (YKL-40), Interleukin-1 beta (IL-1β), Interleukin-9 (IL-9) in ASD children with and without regression compared to healthy controls. Children with ASD (n = 56) and typically developing children (TDC, n = 12) aged 1.11 to 11 years were studied. Mitochondrial activity was examined in peripheral blood mononuclear cells (PBMCs) isolated from children with ASD and from the control group, using a metabolic analyzer. Gene and protein levels of IL-1β, IL-9, COX-2, and YKL-40 were investigated in parallel. Our results showed that PBMCs of the ASD subgroup of regressed patients (ASD R(+), n = 21) had a specific pattern of mitochondrial activity with significantly increased maximal respiration, respiratory spare capacity, and proton leak compared to the non-regressed group (ASD R(-), n = 35) and TDC. Furthermore, we found an imbalance in the studied proinflammatory molecules and increased levels in ASD R(-) proving the involvement of inflammatory changes. The results of this study provide new evidence for specific bioenergetic profiles of immune cells and elevated inflammation-related molecules in ASD. For the first time, data on a unique metabolic profile in ASD R(+) and its comparison with a random group of children of similar age and sex are provided. Our data show that mitochondrial dysfunction is more significant in ASD R(+), while in ASD R(-) inflammation is more pronounced. Probably, in the group without regression, immune mechanisms (immune dysregulation, leading to inflammation) begin initially, and at a later stage mitochondrial activity is also affected under exogenous factors. On the other hand, in the regressed group, the initial damage is in the mitochondria, and perhaps at a later stage immune dysfunction is involved.

Harnessing the Gut Microbiome: To What Extent Can Pre-/Probiotics Alleviate Immune Activation in Autism Spectrum Disorder?

Children diagnosed with autism spectrum disorder (ASD) are at an increased risk of experiencing gastrointestinal (GI) discomfort, which has been linked to dysfunctions in the microbiome-gut-brain axis. The bidirectional communication between gut and brain plays a crucial role in the overall health of individuals, and alterations in the gut microbiome can contribute to immune activation and gut-brain dysfunction in ASD. Despite the limited and controversial results of pre-/probiotic applications in ASD, this review comprehensively maps the association between ASD clinical symptoms and specific bacterial taxa and evaluates the efficacy of pre-/probiotics in modulating microbiota composition, reducing inflammatory biomarkers, alleviating difficulties in GI distress, sleep problems, core and other ASD-associated symptoms, as well as relieving parental concerns, separately, in individuals with ASD. Beyond simply targeting core ASD symptoms, this review highlights the potential of pre-/probiotic supplementations as a strategy to modulate gut homeostasis and immune response, and to delineate the potential mechanisms by which its direct or mediating effects can alleviate gut-brain dysfunction and poor nutritional status in ASD management. Further well-designed randomized controlled trials are needed to strengthen the existing evidence and establish optimal protocols for the use of pre-/probiotics in the context of ASD.