Maternal immune activation as an epidemiological risk factor for neurodevelopmental disorders: Considerations of timing, severity, individual differences, and sex in human and rodent studies

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 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.

Prenatal Exposure to Lipopolysaccharide or Valproate Leads to Abnormal Accumulation of the NMDA Receptor Agonist D-Aspartate in the Adolescent Rat Brain

Autism spectrum disorder (ASD) is a neurodevelopmental psychiatric condition linked to glutamatergic neurotransmission disruption. Although endogenous D-serine and D-aspartate modulate glutamatergic N-methyl D-aspartate receptor (NMDAR) activity, their involvement in ASD remains elusive. We measured the levels of D-aspartate, D-serine, and other key neuroactive amino acids, and their direct precursors in brain regions, plasma, and feces of environmental ASD rat models prenatally exposed to lipopolysaccharide or valproate, both during adolescence and early adulthood, as well as in a genetic ASD model, the Fmr1-Δexon8 rat. No significant changes were found in plasma and feces. Conversely, we observed a prominent accumulation of D-aspartate in several brain regions of lipopolysaccharide- and valproate-exposed rats, selectively during adolescence, while D-serine level variations were more limited. No significant amino acid changes were observed in the Fmr1-Δexon8 rat brain. We also assayed the activity of the main enzymes involved in cerebral D-serine and D-aspartate metabolism, suggesting that their regulation extends beyond their metabolic enzymes. These findings highlight that prenatal environmental stressors disrupt D-amino acid levels selectively in ASD rat brains, emphasizing the role of early NMDAR dysfunction in ASD-related phenotypes.

Association between redox dysregulation and vulnerability to cognitive deficits induced by maternal immune activation

Exposure to maternal immune activation (MIA) in utero is a major risk factor for neurodevelopmental disorders, including schizophrenia. However, a proportion of individuals are resilient to developing schizophrenia following exposure to MIA, which has also been reported in animal models of MIA. The molecular mechanisms leading to resilient and vulnerable behavioural phenotypes remain poorly understood, and we currently lack reliable blood biomarkers that predict resilience or vulnerability. Redox dysregulation, caused by an imbalance between oxidative stress and antioxidant defence mechanisms, has recently been predicted to be central to the pathogenesis of schizophrenia. Here, we use a poly(I:C)-induced MIA model of schizophrenia to investigate mechanisms underlying cognitive dysfunction and redox dysregulation in resilient and vulnerable individuals. We show that activity of the antioxidant enzyme superoxide dismutase (SOD) was reduced in the plasma of poly(I:C) offspring with a cognitive deficit, in contrast to individuals with typical cognition during both adolescence and adulthood. However, SOD activity in the hippocampus was not significantly different between vulnerable and resilient offspring. In addition, the lipid peroxidation marker malondialdehyde (MDA) and the pro-inflammatory cytokine IL-6 were not differentially expressed within the hippocampus or plasma of vulnerable poly(I:C) offspring. Our results suggest that reduced plasma SOD activity may be a potential blood biomarker to identify resilience or vulnerability to MIA-induced cognitive deficits. Further research is necessary to determine if reduced antioxidant capacity is present in plasma prior to symptom presentation and to understand if this predicts redox dysregulation in the brain.

Abnormal microbiota due to prenatal antibiotic as a possible risk factor for Attention-Deficit / Hyperactivity Disorder (ADHD)

One of the major issues modern medicine faces is the increasing use of antibiotics in reaction to the increased incidence of infectious agents. The current trend of antibiotic overuse contributes to microbial dysbiosis. Recent studies have hypothesized that antibiotic exposure during pregnancy, which alters the composition of the microbiome, might increase the likelihood of attention deficit hyperactivity disorder (ADHD). In addition to the ongoing discussion about the potential links between antibiotic usage, microbiome dysbiosis, and ADHD, there is a rising interest in integrating AI and ML into healthcare practices. Diagnosis, treatment plans, and prognoses are all enhanced by these technological advancements. Remote monitors or telemedicine monitoring are among the management techniques described in this chapter for effectively managing illnesses. Also discussed are ways to halt the progression of diseases by preventative measures that use biosensor technology and dietary approaches. Personalized treatment programs, disease progression stages, and prognosis evaluations are all made possible with the use of artificial intelligence and machine learning. By using these technologies to provide individualized therapy, healthcare practitioners may get a better understanding of ADHD and perhaps improve patient outcomes.

Prenatal Maternal Immune Activation with Lipopolysaccharide Accelerates the Developmental Acquisition of Neonatal Reflexes in Rat Offspring Without Affecting Maternal Care Behaviors

Maternal immune activation (MIA)-infection with an immunogen during pregnancy-is linked to an increased risk of neurodevelopmental disorders (NDDs) in offspring. Both MIA and NDDs are associated with developmental delays in offsprings' motor behavior. Therefore, the current study examined the effects of MIA on neonatal reflex development in male and female offspring. Sprague Dawley rats were administered lipopolysaccharide (LPS; 50 μg/mL/kg, i.p.) or saline on embryonic day (E)15 of gestation. The offspring were then tested daily from postnatal day (P)3-P21 to determine their neonatal reflex abilities. The maternal care behaviors of the dam were also quantified on P1-P5, P10, and P15. We found that, regardless of sex, the E15 LPS offspring were able to forelimb grasp, cliff avoid, and right with a correct posture at an earlier postnatal age than the E15 saline offspring did. The E15 LPS offspring also showed better performance of forelimb grasping, hindlimb grasping, righting with correct posture, and walking with correct posture than the E15 saline offspring did. There were no significant differences in maternal licking/grooming, arched-back nursing, non-arched-back nursing, or total nursing across the E15 groups. Overall, these findings suggest that MIA with LPS on E15 accelerates reflex development in offspring without affecting maternal care. This may be explained by the stress acceleration hypothesis, whereby early-life stress accelerates development to promote survival.

Resveratrol prevents offspring's behavioral impairment associated with immunogenic stress during pregnancy

Evidence suggests that prenatal maternal immunological stress is associated with an increased risk of neurological and psychiatric disorders in the developing offspring. Protecting the embryo during this critical period of neurodevelopment, when the brain is especially vulnerable, is therefore crucial. Polyphenols, with their antioxidant and anti-inflammatory properties, offer promising therapeutic approaches. This study demonstrated a series of behavioral changes induced by maternal immune activation (MIA) triggered by an antigenic solution derived from the H1N1 virus. These changes include significant differences in anxiety and risk assessment behaviors, increased immobility in the forced swim test, impairments in memory and object recognition, and social deficits resembling autism. The phenolic compound resveratrol (RSV) was evaluated for its in vitro antioxidant capacity and characterized using infrared spectroscopy. Administering RSV from embryonic day 14 (E14) to embrionyc day 19 (E19) during MIA effectively reduced its harmful effects on the offspring. This was evidenced by a significant restoration of social behaviors, memory, and recognition, as well as anxiolytic and antidepressant effects in the adult offspring. These findings contribute to new therapeutic strategies for preventing psychiatric disorders associated with neurodevelopmental stressors.

Birth Order and Family Size of UK Biobank Subjects Identified as Asexual, Bisexual, Heterosexual, or Homosexual According to Self-Reported Sexual Histories

This study used a recently developed statistical technique to investigate the relations between various elements of a subject's family background and the odds of that subject reporting a sexual history indicative of a minority sexual orientation. The subjects were 78,983 men and 92,150 women who completed relevant questionnaire items in the UK Biobank, a large-scale biomedical database of volunteers aged 40-69 years. The men were divided into three sexual minority groups-homosexual, bisexual, and asexual-and a comparison group of heterosexual men. The same was done for the women. The analytic procedure consisted of logistic regressions specifically designed to disentangle the effects of birth order and family size. The results showed that older brothers increased the odds of homosexuality in both men and women, and that older sisters increased the odds in men. In contrast, neither older brothers or older sisters affected the odds of bisexuality or asexuality in men or in women. These results suggest that birth order effects may be specific to homosexuality and not common to all minority orientations. The only family size finding was the negative association between family size and the odds of asexuality in both men and women. The outcomes of this study indicate that the maternal immune hypothesis, which was advanced to explain the relation between older brothers and homosexuality in later-born males, might have to be abandoned or else expanded to explain the findings concerning females. A few such modifications are considered.

From womb to world: The interplay between maternal immune activation, neuroglia, and neurodevelopment

This chapter introduces and discusses maternal immune activation (MIA) as a contributing factor in increasing the risk of neurodevelopmental disorders, particularly in relation to its interactions with neuroglia. Here we first provide an overview of the neuroglia-astroglia, oligodendroglia, microglia, and radial glial cells-and their important role during early brain development and in adulthood. We then present and discuss MIA, followed by a critical overview of inflammatory molecules and temporal stages associated to maternal inflammation during pregnancy. We provide an overview of animal and human models used to mimic and study MIA. Furthermore, we review the possible interaction between MIA and neuroglia, focusing on the current advances in both modeling and therapeutics. Additionally, we discuss and provide preliminary and interesting insights into the most recent pandemic, COVID-19, and how the infection may be associated to MIA and increased risk for neurodevelopmental disorders. Finally, we provide a critical overview of challenges and future opportunities to study how MIA may contribute to higher risk of developing neurodevelopmental disorders.

Prenatal maternal infections and early childhood developmental outcomes: analysis of linked administrative health data for Greater Glasgow & Clyde, Scotland

BACKGROUND

Previous research has linked prenatal maternal infections to later childhood developmental outcomes and socioemotional difficulties. However, existing studies have relied on retrospectively self-reported survey data, or data on hospital-recorded infections only, resulting in gaps in data collection.

METHODS

This study used a large linked administrative health dataset, bringing together data from birth records, hospital records, prescriptions and routine child health reviews for 55,856 children born in Greater Glasgow & Clyde, Scotland, 2011-2015, and their mothers. Logistic regression models examined associations between prenatal infections, measured as both hospital-diagnosed prenatal infections and receipt of infection-related prescription(s) during pregnancy, and childhood developmental concern(s) identified by health visitors during 6-8 week or 27-30 month health reviews. Secondary analyses examined whether results varied by (a) specific developmental outcome types (gross-motor-skills, hearing-communication, vision-social-awareness, personal-social, emotional-behavioural-attention and speech-language-communication) and (b) the trimester(s) in which infections occurred.

RESULTS

After confounder/covariate adjustment, hospital-diagnosed infections were associated with increased odds of having at least one developmental concern (OR: 1.30; 95% CI: 1.19-1.42). This was broadly consistent across all developmental outcome types and appeared to be specifically linked to infections occurring in pregnancy trimesters 2 (OR: 1.34; 95% CI: 1.07-1.67) and 3 (OR: 1.33; 95% CI: 1.21-1.47), that is the trimesters in which foetal brain myelination occurs. Infection-related prescriptions were not associated with any clear increase in odds of having at least one developmental concern after confounder/covariate adjustment (OR: 1.03; 95% CI: 0.98-1.08), but were associated with slightly increased odds of concerns specifically related to personal-social (OR: 1.12; 95% CI: 1.03-1.22) and emotional-behavioural-attention (OR: 1.15; 95% CI: 1.08-1.22) development.

CONCLUSIONS

Prenatal infections, particularly those which are hospital-diagnosed (and likely more severe), are associated with early childhood developmental outcomes. Prevention of prenatal infections, and monitoring of support needs of affected children, may improve childhood development, but causality remains to be established.

A microglia-containing cerebral organoid model to study early life immune challenges

Prenatal infections and activation of the maternal immune system have been proposed to contribute to causing neurodevelopmental disorders (NDDs), chronic conditions often linked to brain abnormalities. Microglia are the resident immune cells of the brain and play a key role in neurodevelopment. Disruption of microglial functions can lead to brain abnormalities and increase the risk of developing NDDs. How the maternal as well as the fetal immune system affect human neurodevelopment and contribute to NDDs remains unclear. An important reason for this knowledge gap is the fact that the impact of exposure to prenatal risk factors has been challenging to study in the human context. Here, we characterized a model of cerebral organoids (CO) with integrated microglia (COiMg). These organoids express typical microglial markers and respond to inflammatory stimuli. The presence of microglia influences cerebral organoid development, including cell density and neural differentiation, and regulates the expression of several ciliated and mesenchymal cell markers. Moreover, COiMg and organoids without microglia show similar but also distinct responses to inflammatory stimuli. Additionally, IFN-γ induced significant transcriptional and structural changes in the cerebral organoids, that appear to be regulated by the presence of microglia. Specifically, interferon-gamma (IFN-γ) was found to alter the expression of genes linked to autism. This model provides a valuable tool to study how inflammatory perturbations and microglial presence affect neurodevelopmental processes.

High level of immunoglobulin G targeting mycoplasma or cytomegalovirus in the newborn increases risk of ADHD

Attention-deficit hyperactivity disorder (ADHD) is a neurodevelopmental disorder typically detected in childhood. Although ADHD has been demonstrated to have a strong genetic component, environmental risk factors, such as maternal infections during pregnancy, may also play a role. We therefore measured the immunological response to 5 abundant microorganisms (Toxoplasmosis Gondii, cytomegalovirus (CMV), Herpes Simplex Virus 1, Epstein Barr Virus and mycoplasma pneumoniae) in newborn heel prick samples of 1679 ADHD cases and 2948 matching controls as part of the iPSYCH Danish case-cohort study. We found an association between high anti-CMV (OR 1.30, 95 % CI [1.09,1.55], p = 0.015) and anti-mycoplasma (OR 1.30, 95 % CI [1.07,1.59], p = 0.037) signal and those newborns later being diagnosed with ADHD. The risk estimate remained increased when controlling for ADHD polygenic risk score as well as penicillin prescriptions. We saw a dose-response association with the amount of positive anti-microorganism titers increasing the risk of being diagnosed with ADHD later in life (p = 0.01 for the trend), suggesting that the more activated the immune system is prior to or at birth, the higher the risk is for a later diagnosis with ADHD. If the associations are causal, they emphasize the importance of a healthy life style during pregnancy to reduce the risk of infections when pregnant and the associated risks for the child.

Adverse neurodevelopment in children associated with prenatal exposure to fine particulate matter (PM2.5) - Possible roles of polycyclic aromatic hydrocarbons (PAHs) and mechanisms involved

Prenatal exposure to ambient fine particles (PM2.5) and polycyclic aromatic hydrocarbons (PAHs) has been associated with adverse birth outcomes including neurodevelopmental effects with cognitive and/or behavioral implications in early childhood. As a background we first briefly summarize human studies on PM2.5 and PAHs associated with adverse birth outcomes and modified neurodevelopment. Next, we add more specific information from animal studies and in vitro studies and elucidate possible biological mechanisms. More specifically we focus on the potential role of PAHs attached to PM2.5 and explore whether effects of these compounds may arise from disturbance of placental function or more directly by interfering with neurodevelopmental processes in the fetal brain. Possible molecular initiating events (MIEs) include interactions with cellular receptors such as the aryl hydrocarbon receptor (AhR), beta-adrenergic receptors (βAR) and transient receptor potential (TRP)-channels resulting in altered gene expression. MIE linked to the binding of PAHs to cytochrome P450 (CYP) enzymes and formation of reactive electrophilic metabolites are likely less important. The experimental animal and in vitro studies support the epidemiological findings and suggest steps involved in mechanistic pathways explaining the associations. An overall evaluation of the doses/concentrations used in experimental studies combined with the mechanistic understanding further supports the hypothesis that prenatal PAHs exposure may cause adverse outcomes (AOs) linked to human neurodevelopment. Several MIEs will likely occur simultaneously in various cells/tissues involving several key events (KEs) which relative importance will depend on dose, time, tissue, genetics, other environmental factors, and neurodevelopmental endpoint in study.

Neurotoxic effects of perinatal exposure to Bisphenol F on offspring mice

Bisphenols constitute a diverse group of endocrine-disrupting chemicals (EDCs) that impact hormone activity. Bisphenol F (BPF) is commonly used as a substitute for Bisphenol A (BPA). The disruption of the immune system by EDCs during embryonic brain development has been suggested as a plausible factor to neurodevelopmental disorders. We investigated the neurotoxic effects of perinatal exposure to BPF on offspring mice. Female mice were exposed to BPF through their drinking water on day 0.5 of pregnancy, and this exposure continued until the offspring mice were weaned, throughout the perinatal period. Our findings revealed that exposure to BPF hindered both growth and neurodevelopment in offspring mice, with a more pronounced effect observed in males. Additionally, transcriptomic analysis was conducted on the brains of male offspring mice exposed to high doses of BPF. In summary, our study indicates that perinatal exposure to BPF results in neurodevelopmental impairments in male offspring mice, linked to oxidative stress, inflammatory responses, and immune dysregulation. These findings underscore that BPF may not be a safe substitute for BPA. Thus, there is a pressing need to reevaluate the current regulation of BPF.

The Importance of Including Maternal Immune Activation in Animal Models of Hypoxic-Ischemic Encephalopathy

Hypoxic-ischemic encephalopathy (HIE) is a perinatal brain injury that is the leading cause of cerebral palsy, developmental delay, and poor cognitive outcomes in children born at term, occurring in about 1.5 out of 1000 births. The only proven therapy for HIE is therapeutic hypothermia. However, despite this treatment, many children ultimately suffer disability, brain injury, and even death. Barriers to implementation including late diagnosis and lack of resources also lead to poorer outcomes. This demonstrates a critical need for additional treatments for HIE, and to facilitate this, we need translational models that accurately reflect risk factors and interactions present in HIE. Maternal or amniotic infection is a significant risk factor and possible cause of HIE in humans. Maternal immune activation (MIA) is a well-established model of maternal infection and inflammation that has significant developmental consequences largely characterized within the context of neurodevelopmental disorders such as autism spectrum disorder and schizophrenia. MIA can also lead to long-lasting changes within the neuroimmune system, which lead to compounding negative outcomes following a second insult. This supports the importance of understanding the interaction of maternal inflammation and hypoxic-ischemic outcomes. Animal models have been invaluable to understanding the pathophysiology of this injury and to the development of therapeutic hypothermia. However, each model system has its own limitations. Large animal models such as pigs may more accurately represent the brain and organ development and complexity in humans, while rodent models are more cost-effective and offer more possible molecular techniques. Recent studies have utilized MIA or direct inflammation prior to HIE insult. Investigators should thoughtfully consider the risk factors they wish to include in their HIE animal models. In the incorporation of MIA, investigators should consider the type, timing, and dose of the inflammatory stimulus, as well as the timing, severity, and type of hypoxic insult. Using a variety of animal models that incorporate the maternal-placental-fetal system of inflammation will most likely lead to a more robust understanding of the mechanisms of this injury that can guide future clinical decisions and therapies.

Developmental functions of microglia: Impact of psychosocial and physiological early life stress

Microglia play numerous important roles in brain development. From early embryonic stages through adolescence, these immune cells influence neuronal genesis and maturation, guide connectivity, and shape brain circuits. They also interact with other glial cells and structures, influencing the brain's supportive microenvironment. While this central role makes microglia essential, it means that early life perturbations to microglia can have widespread effects on brain development, potentially resulting in long-lasting behavioral impairments. Here, we will focus on the effects of early life psychosocial versus physiological stressors in rodent models. Psychosocial stress refers to perceived threats that lead to stress axes activation, including prenatal stress, or chronic postnatal stress, including maternal separation and resource scarcity. Physiological stress refers to physical threats, including maternal immune activation, postnatal infection, and traumatic brain injury. Differing sources of early life stress have varied impacts on microglia, and these effects are moderated by factors such as developmental age, brain region, and sex. Overall, these stressors appear to either 1) upregulate basal microglia numbers and activity throughout the lifespan, while possibly blunting their responsivity to subsequent stressors, or 2) shift the developmental curve of microglia, resulting in differential timing and function, impacting the critical periods they govern. Either could contribute to behavioral dysfunctions that occur after the resolution of early life stress. Exploring how different stressors impact microglia, as well as how multiple stressors interact to alter microglia's developmental functions, could deepen our understanding of how early life stress changes the brain's developmental trajectory. This article is part of the Special Issue on "Microglia".

Correlation of biochemical markers and inflammatory cytokines in autism spectrum disorder (ASD)

INTRODUCTION

Autism Spectrum Disorder (ASD) is a disorder that severely affects neurodevelopment, and its underlying causes are not yet entirely understood. Research suggests that there may be a connection between the occurrence of ASD and changes in immune responses. This study aims to know if some biochemical and inflammatory cytokines are promising biomarkers for ASD and whether they are involved in the pathogenesis of ASD.

METHODS

The serum levels of CRP, TNF-α, TGF-β, IL-1β, IL-10, 1 L-8, and IL-6 were measured in all of the patients (n = 22) and in the healthy (n = 12) children using ELISA method.

RESULTS

The serum concentrations of IL-10 and IL-8 were significantly lower in the ASD patients compared to the control group (p < 0.05) and there were not significant differences between CRP, TNF-α, TGF-β, IL-6 and IL-1β levels in two groups. There were positive correlations between CRP and IL-10, also CRP and IL-8, in ASD group. In contrast to the ASD patients, the correlations of IL-8, IL-10, and CRP were not significant in the control group.

CONCLUSION

In conclusion, this study highlights the potential role of certain biochemical markers and inflammatory cytokines in ASD. Specifically, the lower levels of IL-10 and IL-8 in ASD patients, along with the significant correlations between CRP and these cytokines, suggest an altered immune response in individuals with ASD. These findings support the hypothesis that immune dysregulation may be involved in ASD pathogenesis. Further research is needed to explore these biomarkers and their mechanistic links to ASD, which could lead to improved diagnostics or therapeutic strategies.

Salivary IL-1 Beta Level Associated with Poor Sleep Quality in Children/Adolescents with Autism Spectrum Disorder

BACKGROUND

Sleep disorders are common in youths with autism spectrum disorders. Inflammatory cytokines such as Il-1 beta and Il-6 in saliva have been associated with alterations in sleep quality in various conditions. We assessed whether there were associations between the salivary concentration of IL-1 beta and IL-6 and sleep quality in youths with ASD versus typically developing (TD) age- and gender-matched youths.

METHOD

Forty children and adolescents with ASD or TD participated in this study (20% females). Their parents answered the items of a validated questionnaire on sleep quality (Pittsburgh Sleep Quality Index).

RESULTS

The mean Pittsburgh score was significantly higher (i.e., the quality of sleep was poorer) in the ASD group (8.68 ± 0.35 (SEM), ranging from 7 to 12 points), compared to the TD group (7.35 ± 0.54 (SEM), ranging from 2 to 12 points) (p = 0.02, Mann-Whitney U test). There were no significant differences in the salivary concentration of Il-1 beta and IL-6 receptor between the two groups, but salivary IL-1 beta concentration was inversely associated with poor sleep quality in the ASD group. No associations between the salivary Il-6 concentration and sleep quality were found in either group. Linear regression analysis by separate groups revealed significant associations between the sleep quality score and the concentration of IL-1 beta in the ASD group (p = 0.01, OR = -0.53, 95% CI -0.008-0.001). In contrast, no significant associations were observed in the TD group, or for IL-6 in either group. No significant effects of sex, age, or use of psychotropic medications were found.

CONCLUSIONS

Children and adolescents with ASD showed significantly poorer sleep quality based on their parents' reports compared to the TD group, and the salivary IL-1 beta concentration was inversely associated with sleep quality only in the ASD group. Further studies on the associations between inflammatory cytokines and sleep in ASD are needed.

An integrative exploration of environmental stressors on the microbiome-gut-brain axis and immune mechanisms promoting neurological disorders

The microbiome-gut-brain axis is altered by environmental stressors such as heat, diet, and pollutants as well as microbes in the air, water, and soil. These stressors might alter the host's microbiome and symbiotic relationship by modifying the microbial composition or location. Compartmentalized mutualistic microbes promote the beneficial interactions in the host leading to circulating metabolites and hormones such as insulin and leptin that affect inter-organ functions. Inflammation and oxidative stress induced by environmental stressors may alter the composition, distribution, and activities of the microbes in the microbiomes such that the resultant metabolite and hormone changes are no longer beneficial. The microbiome-gut-brain axis and immune adverse changes that may accompany environmental stressors are reviewed for effects on innate and adaptive immune cells, which may make host immunity less responsive to pathogens and more reactive to self-antigens. Cardiovascular and fluid exchanges to organs might adversely alter organ functionality. Organs, especially the brain, need a consistent supply of nutrients and clearance of debris; disruption of these exchanges by stressors, and involvement of gut microbiome are discussed regarding neural dysfunctions with Alzheimer's disease, autistic spectrum disorders, viral infections, and autoimmune diseases. The focus of this review includes the manner in which environmental stressors may disrupt gut microbiota leading to adverse immune and hormonal influences on development of neuropathology related to hyperhomocysteinemia, inflammation, and oxidative stress, and how certain therapeutics may be beneficial. Strategies are explored to lessen detrimental effects of environmental stressors on central and peripheral health navigated toward (1) understanding neurological disorders and (2) promoting environmental and public health and well-being.

In Utero Exposure to Maternal COVID-19 and Offspring Neurodevelopment Through Age 24 Months

Importance

In utero exposure to maternal infections has been associated with abnormal neurodevelopment among offspring. The emergence of a new, now endemic infection (SARS-CoV-2) warrants investigating developmental implications for exposed offspring.

Objective

To assess whether in utero exposure to maternal COVID-19 is associated with abnormal neurodevelopmental scores among children ages 12, 18, and 24 months.

Design, Setting, and Participants

Data were ascertained from the ASPIRE (Assessing the Safety of Pregnancy in the Coronavirus Pandemic) trial, a prospective cohort of pregnant individuals aged 18 years or older who were enrolled before 10 weeks' gestation and their children. Individuals were recruited online from May 14, 2020, to August 23, 2021, using the Society for Assisted Reproductive Technology and BabyCenter, an online media platform. Participants from all 50 states and Puerto Rico completed activities remotely.

Exposure

In utero exposure to COVID-19.

Main Outcomes and Measures

Birth mothers completed the Ages & Stages Questionnaires, Third Edition, a validated screening tool for developmental delays, at 12, 18, and 24 months' post partum. A score below the cutoff in any domain (communication, gross motor, fine motor, problem-solving, and social skills) was considered an abnormal developmental screen (scores range from 0 to 60 in each domain, with higher scores indicating less risk for neurodevelopmental delay).

Results

The cohort included 2003 pregnant individuals (mean [SD] age, 33.3 [4.2] years) enrolled before 10 weeks' gestation and who completed study activities; 1750 (87.4%) had earned a college degree. Neurodevelopmental outcomes were available for 1757 children at age 12 months, 1522 at age 18 months, and 1523 at age 24 months. The prevalence of abnormal screens for exposed vs unexposed offspring at age 12 months was 64 of 198 (32.3%) vs 458 of 1559 (29.4%); at age 18 months, 36 of 161 (22.4%) vs 279 of 1361 (20.5%); and at age 24 months, 29 of 151 (19.2%) vs 230 of 1372 (16.8%). In an adjusted mixed-effects logistics regression model, no difference in risk of abnormal neurodevelopmental screens was observed at age 12 months (adjusted risk ratio [ARR], 1.07 [95% CI, 0.85-1.34]), age 18 months (ARR, 1.15 [95% CI, 0.84-1.57]), or age 24 months (ARR, 1.01 [95% CI, 0.69-1.48]). Supplemental analyses did not identify differential risk based on trimester of infection, presence vs absence of fever, or breakthrough infection following vaccination vs primary infection.

Conclusions and Relevance

In this cohort study of pregnant individuals and offspring, exposure to maternal COVID-19 was not associated with abnormal neurodevelopmental screening results through 24 months' post partum. Continued study of diverse groups of children is needed because, among other factors, evidence suggests sensitivity of the developing fetal brain to maternal immune activation.

Maternal immune response during pregnancy and neurodevelopmental outcomes: A longitudinal approach

Background and objectives

The neurodevelopment of the offspring is suggested to be influenced by the maternal immune system's responses throughout pregnancy, which in turn is also vulnerable to maternal psychosocial stress conditions. Therefore, our main goal was to investigate whether maternal peripheral immunological biomarkers (IB) during two stages of gestation are associated with distinct neurodevelopmental trajectories in the first two years of life. As a second goal, we also explored the association between maternal distal (childhood) and proximal (gestation) stressful experiences and the immunological markers assessed during pregnancy.

Methods

Maternal childhood trauma, depressive and anxiety symptoms, and peripheral IB (IFNγ, IL-10, IL1β, IL6, IL8, TNFα, EGF, IL13, IL17, IL1Ra and IL4) were measured at baseline (8-16 weeks of pregnancy) and at 30 weeks of pregnancy in 160 women. The participants had the blood samples collected from two randomized clinical trials conducted by the same team and methods in the same community. A Principal Component Analysis (PCA) was implemented to create meaningful composite variables that describe the cytokines joint variation. Finally, linear mixed-effects modeling was used to investigate the influence of inflammatory biomarkers, maternal childhood trauma, anxiety, and depressive symptoms on Bayley's III scores trajectories.

Results

The IB profile during the 3rd trimester of pregnancy predicted the offspring's neurodevelopmental trajectories in the first two years of life. The components derived from PCA were important predictors and captured different immune responses, reflecting both pro- and anti-inflammatory states. Maternal stressful experiences did not correlate with the immunological markers. Although not a reliable predictor alone, maternal psychosocial stress at the 1st trimester of pregnancy interacted with the mother's immune response while predicting the neurodevelopmental scores during the first two years of life.

Conclusions

Our results underscore the importance of the maternal immune response during pregnancy in shaping the neurodevelopmental trajectory of the offspring. Additionally, we observed that the maternal distress at the early stages of pregnancy has an incremental effect on the neurodevelopmental outcome but depends upon the immune response.

Synaptic proteome perturbations after maternal immune activation: Identification of embryonic and adult hippocampal changes

BACKGROUND

Maternal immune activation (MIA) triggers neurobiological changes in offspring, potentially reshaping the molecular synaptic landscape, with the hippocampus being particularly vulnerable. However, critical details regarding developmental timing of these changes and whether they differ between males and females remain unclear.

METHODS

We induced MIA in C57BL/6J mice on gestational day nine using the viral mimetic poly(I:C) and performed mass spectrometry-based proteomic analyses on hippocampal synaptoneurosomes of embryonic (E18) and adult (20 ± 1 weeks) MIA offspring.

RESULTS

In the embryonic synaptoneurosomes, MIA led to lipid, polysaccharide, and glycoprotein metabolism pathway disruptions. In the adult synaptic proteome, we observed a dynamic shift toward transmembrane trafficking, intracellular signalling cascades, including cell death and growth, and cytoskeletal organisation. In adults, many associated pathways overlapped between males and females. However, we found distinct sex-specific enrichment of dopaminergic and glutamatergic pathways. We identified 50 proteins altered by MIA in both embryonic and adult samples (28 with the same directionality), mainly involved in presynaptic structure and synaptic vesicle function. We probed human phenome-wide association study data in the cognitive and psychiatric domains, and 49 of the 50 genes encoding these proteins were significantly associated with the investigated phenotypes.

CONCLUSIONS

Our data emphasise the dynamic effects of viral-like MIA on developing and mature hippocampi and provide novel targets for study following prenatal immune challenges. The 22 proteins that changed directionality from the embryonic to adult hippocampus, suggestive of compensatory over-adaptions, are particularly attractive for future investigations.

A Novel Non-Invasive Murine Model of Neonatal Hypoxic-Ischemic Encephalopathy Demonstrates Developmental Delay and Motor Deficits with Activation of Inflammatory Pathways in Monocytes

Neonatal hypoxic-ischemic encephalopathy (HIE) occurs in 1.5 per 1000 live births, leaving affected children with long-term motor and cognitive deficits. Few animal models of HIE incorporate maternal immune activation (MIA) despite the significant risk MIA poses to HIE incidence and diagnosis. Our non-invasive model of HIE pairs late gestation MIA with postnatal hypoxia. HIE pups exhibited a trend toward smaller overall brain size and delays in the ontogeny of several developmental milestones. In adulthood, HIE animals had reduced strength and gait deficits, but no difference in speed. Surprisingly, HIE animals performed better on the rotarod, an assessment of motor coordination. There was significant upregulation of inflammatory genes in microglia 24 h after hypoxia. Single-cell RNA sequencing (scRNAseq) revealed two microglia subclusters of interest following HIE. Pseudobulk analysis revealed increased microglia motility gene expression and upregulation of epigenetic machinery and neurodevelopmental genes in macrophages following HIE. No sex differences were found in any measures. These results support a two-hit noninvasive model pairing MIA and hypoxia as a model for HIE in humans. This model results in a milder phenotype compared to established HIE models; however, HIE is a clinically heterogeneous injury resulting in a variety of outcomes in humans. The pathways identified in our model of HIE may reveal novel targets for therapy for neonates with HIE.

Maternal immune activation and its multifaceted effects on learning and memory in rodent offspring: A systematic review

This systematic review explored the impact of maternal immune activation (MIA) on learning and memory behavior in offspring, with a particular focus on sexual dimorphism. We analyzed 20 experimental studies involving rodent models (rats and mice) exposed to either lipopolysaccharide (LPS) or POLY I:C during gestation following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Our findings reveal that most studies report a detrimental impact of MIA on the learning and memory performance of offspring, highlighting the significant role of prenatal environmental factors in neurodevelopment. Furthermore, this review underscores the complex effects of sex, with males often exhibiting more pronounced cognitive impairment compared to females. Notably, a small subset of studies report enhanced cognitive function following MIA, suggesting complex, context-dependent outcomes of prenatal immune challenges. This review also highlights sex differences caused by the effects of MIA in terms of cytokine responses, alterations in gene expression, and differences in microglial responses as factors that contribute to the cognitive outcomes observed.

Inhibitory Systems in Brain Evolution: Pathways of Vulnerability in Neurodevelopmental Disorders

BACKGROUND

The evolution of the primate brain has been characterized by the reorganization of key structures and circuits underlying derived specializations in sensory systems, as well as social behavior and cognition. Among these, expansion and elaboration of the prefrontal cortex has been accompanied by alterations to the connectivity and organization of subcortical structures, including the striatum and amygdala, underlying advanced aspects of executive function, inhibitory behavioral control, and socioemotional cognition seen in our lineages. At the cellular level, the primate brain has further seen an increase in the diversity and number of inhibitory GABAergic interneurons. A prevailing hypothesis holds that disruptions in the balance of excitatory to inhibitory activity in the brain underlies the pathophysiology of many neurodevelopmental and psychiatric disorders.

SUMMARY

This review highlights the evolution of inhibitory brain systems and circuits and suggests that recent evolutionary modifications to GABAergic circuitry may provide the substrate for vulnerability to aberrant neurodevelopment. We further discuss how modifications to primate and human social organization and life history may shape brain development in ways that contribute to neurodivergence and the origins of neurodevelopmental disorders.

KEY MESSAGES

Many brain systems have seen functional reorganization in the mammalian, primate, and human brain. Alterations to inhibitory circuitry in frontostriatal and frontoamygdalar systems support changes in social behavior and cognition. Increased complexity of inhibitory systems may underlie vulnerabilities to neurodevelopmental and psychiatric disorders, including autism and schizophrenia. Changes observed in Williams syndrome may further elucidate the mechanisms by which alterations in inhibitory systems lead to changes in behavior and cognition. Developmental processes, including altered neuroimmune function and age-related vulnerability of inhibitory cells and synapses, may lead to worsening symptomatology in neurodevelopmental and psychiatric disorders.

BACKGROUND

The evolution of the primate brain has been characterized by the reorganization of key structures and circuits underlying derived specializations in sensory systems, as well as social behavior and cognition. Among these, expansion and elaboration of the prefrontal cortex has been accompanied by alterations to the connectivity and organization of subcortical structures, including the striatum and amygdala, underlying advanced aspects of executive function, inhibitory behavioral control, and socioemotional cognition seen in our lineages. At the cellular level, the primate brain has further seen an increase in the diversity and number of inhibitory GABAergic interneurons. A prevailing hypothesis holds that disruptions in the balance of excitatory to inhibitory activity in the brain underlies the pathophysiology of many neurodevelopmental and psychiatric disorders.

SUMMARY

This review highlights the evolution of inhibitory brain systems and circuits and suggests that recent evolutionary modifications to GABAergic circuitry may provide the substrate for vulnerability to aberrant neurodevelopment. We further discuss how modifications to primate and human social organization and life history may shape brain development in ways that contribute to neurodivergence and the origins of neurodevelopmental disorders.

KEY MESSAGES

Many brain systems have seen functional reorganization in the mammalian, primate, and human brain. Alterations to inhibitory circuitry in frontostriatal and frontoamygdalar systems support changes in social behavior and cognition. Increased complexity of inhibitory systems may underlie vulnerabilities to neurodevelopmental and psychiatric disorders, including autism and schizophrenia. Changes observed in Williams syndrome may further elucidate the mechanisms by which alterations in inhibitory systems lead to changes in behavior and cognition. Developmental processes, including altered neuroimmune function and age-related vulnerability of inhibitory cells and synapses, may lead to worsening symptomatology in neurodevelopmental and psychiatric disorders.

From Womb to World: Exploring the Immunological Connections between Mother and Child

Mother and child are immunologically interconnected by mechanisms that we are only beginning to understand. During pregnancy, multiple molecular and cellular factors of maternal origin are transferred across the placenta and influence the development and function of the fetal and newborn immune system. Altered maternal immune states arising from pregnancy-associated infections or immunizations have the potential to program offspring immune function in ways that may have long-term health consequences. In this study, we review current literature on the impact of prenatal infection and vaccination on the developing immune system, highlight knowledge gaps, and look to the horizon to envision maternal interventions that could benefit both the mother and her child.

Risk of Neurodevelopmental Disorders in Offspring of Parents with Major Depressive Disorder: A Birth Cohort Study

Studies have reported inconsistent results regarding associations between parental depression and offspring neurodevelopmental disorders, such as developmental delay and autism spectrum disorder (ASD). In all, 7,593 children who were born between 1996 and 2010 in Taiwan and had at least one parent with major depressive disorder and 75,930 birth-year- and sex-matched children of parents without major depressive disorder were followed from 1996 or time of birth to the end of 2011. Intergroup differences in neurodevelopmental conditions-including ASD, attention-deficit hyperactivity disorder (ADHD), tic disorder, developmental delay, and intellectual disability (ID)-were assessed. Compared with the children in the control group, the children of parents with major depression were more likely [hazard ratio (HR), 95% confidence interval (CI)] to develop ADHD (1.98, 1.80-2.18), ASD (1.52, 1.16-1.94), tic disorder (1.40, 1.08-1.81), developmental delay (1.32, 1.20-1.45), and ID (1.26, 1.02-1.55). Parental depression was associated with offspring neurodevelopmental disorders, specifically ASD, ADHD, developmental delay, ID, and tic disorder. Therefore, clinicians should closely monitor the neurodevelopmental conditions of children of parents with depression.

Dynamic stress- and inflammatory-based regulation of psychiatric risk loci in human neurons

The prenatal environment can alter neurodevelopmental and clinical trajectories, markedly increasing risk for psychiatric disorders in childhood and adolescence. To understand if and how fetal exposures to stress and inflammation exacerbate manifestation of genetic risk for complex brain disorders, we report a large-scale context-dependent massively parallel reporter assay (MPRA) in human neurons designed to catalogue genotype x environment (GxE) interactions. Across 240 genome-wide association study (GWAS) loci linked to ten brain traits/disorders, the impact of hydrocortisone, interleukin 6, and interferon alpha on transcriptional activity is empirically evaluated in human induced pluripotent stem cell (hiPSC)-derived glutamatergic neurons. Of ~3,500 candidate regulatory risk elements (CREs), 11% of variants are active at baseline, whereas cue-specific CRE regulatory activity range from a high of 23% (hydrocortisone) to a low of 6% (IL-6). Cue-specific regulatory activity is driven, at least in part, by differences in transcription factor binding activity, the gene targets of which show unique enrichments for brain disorders as well as co-morbid metabolic and immune syndromes. The dynamic nature of genetic regulation informs the influence of environmental factors, reveals a mechanism underlying pleiotropy and variable penetrance, and identifies specific risk variants that confer greater disorder susceptibility after exposure to stress or inflammation. Understanding neurodevelopmental GxE interactions will inform mental health trajectories and uncover novel targets for therapeutic intervention.

Interplay of polygenic liability with birth-related, somatic, and psychosocial factors in anorexia nervosa risk: a nationwide study

BACKGROUND

Although several types of risk factors for anorexia nervosa (AN) have been identified, including birth-related factors, somatic, and psychosocial risk factors, their interplay with genetic susceptibility remains unclear. Genetic and epidemiological interplay in AN risk were examined using data from Danish nationwide registers. AN polygenic risk score (PRS) and risk factor associations, confounding from AN PRS and/or parental psychiatric history on the association between the risk factors and AN risk, and interactions between AN PRS and each level of target risk factor on AN risk were estimated.

METHODS

Participants were individuals born in Denmark between 1981 and 2008 including nationwide-representative data from the iPSYCH2015, and Danish AN cases from the Anorexia Nervosa Genetics Initiative and Eating Disorder Genetics Initiative cohorts. A total of 7003 individuals with AN and 45 229 individuals without a registered AN diagnosis were included. We included 22 AN risk factors from Danish registers.

RESULTS

Risk factors showing association with PRS for AN included urbanicity, parental ages, genitourinary tract infection, and parental socioeconomic factors. Risk factors showed the expected association to AN risk, and this association was only slightly attenuated when adjusted for parental history of psychiatric disorders or/and for the AN PRS. The interaction analyses revealed a differential effect of AN PRS according to the level of the following risk factors: sex, maternal age, genitourinary tract infection, C-section, parental socioeconomic factors and psychiatric history.

CONCLUSIONS

Our findings provide evidence for interactions between AN PRS and certain risk-factors, illustrating potential diverse risk pathways to AN diagnosis.

A microglia-containing cerebral organoid model to study early life immune challenges

Prenatal infections and activation of the maternal immune system have been proposed to contribute to causing neurodevelopmental disorders (NDDs), chronic conditions often linked to brain abnormalities. Microglia are the resident immune cells of the brain and play a key role in neurodevelopment. Disruption of microglial functions can lead to brain abnormalities and increase the risk of developing NDDs. How the maternal as well as the fetal immune system affect human neurodevelopment and contribute to NDDs remains unclear. An important reason for this knowledge gap is the fact that the impact of exposure to prenatal risk factors has been challenging to study in the human context. Here, we characterized a model of cerebral organoids (CO) with integrated microglia (COiMg). These organoids express typical microglial markers and respond to inflammatory stimuli. The presence of microglia influences cerebral organoid development, including cell density and neural differentiation, and regulates the expression of several ciliated mesenchymal cell markers. Moreover, COiMg and organoids without microglia show similar but also distinct responses to inflammatory stimuli. Additionally, IFN-γ induced significant transcriptional and structural changes in the cerebral organoids, that appear to be regulated by the presence of microglia. Specifically, interferon-gamma (IFN-γ) was found to alter the expression of genes linked to autism. This model provides a valuable tool to study how inflammatory perturbations and microglial presence affect neurodevelopmental processes.

Altered cytokine and chemokine profile linked to autoantibody and pathogen reactivity in mothers of autistic children

Maternal autoimmunity, and more specifically, the production of specific maternal autoantibodies, has been associated with altered offspring neurodevelopment. Maternal autoantibody-related (MAR) autism is a subtype of autism that is linked to gestational exposure to certain combinations of autoantibodies to proteins known to be important for fetal neurodevelopment. We wanted to address whether mothers with autism-specific patterns of autoantibodies have a skewed cytokine and chemokine profile during an immune response to infection. To do so, we examined a subset of mothers from the Early Markers for Autism (EMA) study who either produced known patterns of MAR autoantibodies (MAR+) or did not (MAR-). We compared the cytokine/chemokine profiles of MAR+ and MAR- mothers in the context of positive immunoglobulin G (IgG) reactivity to several viral and parasitic agents. We observed that MAR+ mothers have a higher level of proinflammatory cytokine interferon-gamma regardless of IgG status. Additionally, when comparing MAR+ and MAR- mothers in the context of the different pathogens, MAR+ mothers consistently had increases in multiple proinflammatory cytokines and chemokines.

Whole exome sequencing identified a homozygous novel variant in DOP1A gene in the Pakistan family with neurodevelopmental disabilities: case report and literature review

Background

Hereditary neurodevelopmental disorders (NDDs) are prevalent in poorly prognostic pediatric diseases, but the pathogenesis of NDDs is still unclear. Irregular myelination could be one of the possible causes of NDDs.

Case presentation

Here, whole exome sequencing was carried out for a consanguineous Pakistani family with NDDs to identify disease-associated variants. The co-segregation of candidate variants in the family was validated using Sanger sequencing. The potential impact of the gene on NDDs has been supported by conservation analysis, protein prediction, and expression analysis. A novel homozygous variant DOP1A(NM_001385863.1):c.2561A>G was identified. It was concluded that the missense variant might affect the protein-protein binding sites of the critical MEC interaction region of DOP1A, and DOP1A-MON2 may cause stability deficits in Golgi-endosome protein traffic. Proteolipid protein (PLP) and myelin-associate glycoprotein (MAG) could be targets of the DOP1A-MON2 Golgi-endosome traffic complex, especially during the fetal stage and the early developmental stages. This further supports the perspective that disorganized myelinogenesis due to congenital DOP1A deficiency might cause neurodevelopmental disorders (NDDs).

Conclusion

Our case study revealed the potential pathway of myelinogenesis-relevant NDDs and identified DOP1A as a potential NDDs-relevant gene in humans.

Current perspectives on perinatal mental health and neurobehavioral development: focus on regulation, coregulation and self-regulation

PURPOSE OF REVIEW

Perinatal mental health research provides an important perspective on neurobehavioral development. Here, we aim to review the association of maternal perinatal health with offspring neurodevelopment, providing an update on (self-)regulation problems, hypothesized mechanistic pathways, progress and challenges, and implications for mental health.

RECENT FINDINGS

(1) Meta-analyses confirm that maternal perinatal mental distress is associated with (self-)regulation problems which constitute cognitive, behavioral, and affective social-emotional problems, while exposure to positive parental mental health has a positive impact. However, effect sizes are small. (2) Hypothesized mechanistic pathways underlying this association are complex. Interactive and compensatory mechanisms across developmental time are neglected topics. (3) Progress has been made in multiexposure studies. However, challenges remain and these are shared by clinical, translational and public health sciences. (4) From a mental healthcare perspective, a multidisciplinary and system level approach employing developmentally-sensitive measures and timely treatment of (self-)regulation and coregulation problems in a dyadic caregiver-child and family level approach seems needed. The existing evidence-base is sparse.

SUMMARY

During the perinatal period, addressing vulnerable contexts and building resilient systems may promote neurobehavioral development. A pluralistic approach to research, taking a multidisciplinary approach to theoretical models and empirical investigation needs to be fostered.

Shedding a Light on Dark Genes: A Comparative Expression Study of PRR12 Orthologues during Zebrafish Development

Haploinsufficiency of the PRR12 gene is implicated in a human neuro-ocular syndrome. Although identified as a nuclear protein highly expressed in the embryonic mouse brain, PRR12 molecular function remains elusive. This study explores the spatio-temporal expression of zebrafish PRR12 co-orthologs, prr12a and prr12b, as a first step to elucidate their function. In silico analysis reveals high evolutionary conservation in the DNA-interacting domains for both orthologs, with significant syntenic conservation observed for the prr12b locus. In situ hybridization and RT-qPCR analyses on zebrafish embryos and larvae reveal distinct expression patterns: prr12a is expressed early in zygotic development, mainly in the central nervous system, while prr12b expression initiates during gastrulation, localizing later to dopaminergic telencephalic and diencephalic cell clusters. Both transcripts are enriched in the ganglion cell and inner neural layers of the 72 hpf retina, with prr12b widely distributed in the ciliary marginal zone. In the adult brain, prr12a and prr12b are found in the cerebellum, amygdala and ventral telencephalon, which represent the main areas affected in autistic patients. Overall, this study suggests PRR12's potential involvement in eye and brain development, laying the groundwork for further investigations into PRR12-related neurobehavioral disorders.

Loss of interleukin 1 signaling causes impairment of microglia- mediated synapse elimination and autistic-like behaviour in mice

In the last years, the hypothesis that elevated levels of proinflammatory cytokines contribute to the pathogenesis of neurodevelopmental diseases has gained popularity. IL-1 is one of the main cytokines found to be elevated in Autism spectrum disorder (ASD), a complex neurodevelopmental condition characterized by defects in social communication and cognitive impairments. In this study, we demonstrate that mice lacking IL-1 signaling display autistic-like defects associated with an excessive number of synapses. We also show that microglia lacking IL-1 signaling at early neurodevelopmental stages are unable to properly perform the process of synapse engulfment and display excessive activation of mammalian target of rapamycin (mTOR) signaling. Notably, even the acute inhibition of IL-1R1 by IL-1Ra is sufficient to enhance mTOR signaling and reduce synaptosome phagocytosis in WT microglia. Finally, we demonstrate that rapamycin treatment rescues the defects in IL-1R deficient mice. These data unveil an exclusive role of microglial IL-1 in synapse refinement via mTOR signaling and indicate a novel mechanism possibly involved in neurodevelopmental disorders associated with defects in the IL-1 pathway.

In Utero Exposure to Maternal COVID-19 Vaccination and Offspring Neurodevelopment at 12 and 18 Months

Importance

Uptake of COVID-19 vaccines among pregnant individuals was hampered by safety concerns around potential risks to unborn children. Data clarifying early neurodevelopmental outcomes of offspring exposed to COVID-19 vaccination in utero are lacking.

Objective

To determine whether in utero exposure to maternal COVID-19 vaccination was associated with differences in scores on the Ages and Stages Questionnaire, third edition (ASQ-3), at 12 and 18 months of age.

Design, Setting, and Participants

This prospective cohort study, Assessing the Safety of Pregnancy During the Coronavirus Pandemic (ASPIRE), enrolled pregnant participants from May 2020 to August 2021; follow-up of children from these pregnancies is ongoing. Participants, which included pregnant individuals and their offspring from all 50 states, self-enrolled online. Study activities were performed remotely.

Exposure

In utero exposure of the fetus to maternal COVID-19 vaccination during pregnancy was compared with those unexposed.

Main Outcomes and Measures

Neurodevelopmental scores on validated ASQ-3, completed by birth mothers at 12 and 18 months. A score below the established cutoff in any of 5 subdomains (communication, gross motor, fine motor, problem solving, social skills) constituted an abnormal screen for developmental delay.

Results

A total of 2487 pregnant individuals (mean [SD] age, 33.3 [4.2] years) enrolled at less than 10 weeks' gestation and completed research activities, yielding a total of 2261 and 1940 infants aged 12 and 18 months, respectively, with neurodevelopmental assessments. In crude analyses, 471 of 1541 exposed infants (30.6%) screened abnormally for developmental delay at 12 months vs 203 of 720 unexposed infants (28.2%; χ2 = 1.32; P = .25); the corresponding prevalences at 18 months were 262 of 1301 (20.1%) vs 148 of 639 (23.2%), respectively (χ2 = 2.35; P = .13). In multivariable mixed-effects logistic regression models adjusting for maternal age, race, ethnicity, education, income, maternal depression, and anxiety, no difference in risk for abnormal ASQ-3 screens was observed at either time point (12 months: adjusted risk ratio [aRR], 1.14; 95% CI, 0.97-1.33; 18 months: aRR, 0.88; 95% CI, 0.72-1.07). Further adjustment for preterm birth and infant sex did not affect results (12 months: aRR, 1.16; 95% CI, 0.98-1.36; 18 months: aRR, 0.87; 95% CI, 0.71-1.07).

Conclusions and Relevance

Results of this cohort study suggest that COVID-19 vaccination was safe during pregnancy from the perspective of infant neurodevelopment to 18 months of age. Additional longer-term research should be conducted to corroborate these findings and buttress clinical guidance with a strong evidence base.

Existing and Future Strategies to Manipulate the Gut Microbiota With Diet as a Potential Adjuvant Treatment for Psychiatric Disorders

Nutrition and diet quality play key roles in preventing and slowing cognitive decline and have been linked to multiple brain disorders. This review compiles available evidence from preclinical studies and clinical trials on the impact of nutrition and interventions regarding major psychiatric conditions and some neurological disorders. We emphasize the potential role of diet-related microbiome alterations in these effects and highlight commonalities between various brain disorders related to the microbiome. Despite numerous studies shedding light on these findings, there are still gaps in our understanding due to the limited availability of definitive human trial data firmly establishing a causal link between a specific diet and microbially mediated brain functions and symptoms. The positive impact of certain diets on the microbiome and cognitive function is frequently ascribed with the anti-inflammatory effects of certain microbial metabolites or a reduction of proinflammatory microbial products. We also critically review recent research on pro- and prebiotics and nondietary interventions, particularly fecal microbiota transplantation. The recent focus on diet in relation to brain disorders could lead to improved treatment outcomes with combined dietary, pharmacological, and behavioral interventions.

A choroid plexus apocrine secretion mechanism shapes CSF proteome and embryonic brain development

We discovered that apocrine secretion by embryonic choroid plexus (ChP) epithelial cells contributes to the cerebrospinal fluid (CSF) proteome and influences brain development in mice. The apocrine response relies on sustained intracellular calcium signaling and calpain-mediated cytoskeletal remodeling. It rapidly alters the embryonic CSF proteome, activating neural progenitors lining the brain's ventricles. Supraphysiological apocrine secretion induced during mouse development by maternal administration of a serotonergic 5HT2C receptor agonist dysregulates offspring cerebral cortical development, alters the fate of CSF-contacting neural progenitors, and ultimately changes adult social behaviors. Critically, exposure to maternal illness or to the psychedelic drug LSD during pregnancy also overactivates the ChP, inducing excessive secretion. Collectively, our findings demonstrate a new mechanism by which maternal exposure to diverse stressors disrupts in utero brain development.

Developmental synapse pathology triggered by maternal exposure to the herbicide glufosinate ammonium

Environmental and genetic factors influence synapse formation. Numerous animal experiments have revealed that pesticides, including herbicides, can disturb normal intracellular signals, gene expression, and individual animal behaviors. However, the mechanism underlying the adverse outcomes of pesticide exposure remains elusive. Herein, we investigated the effect of maternal exposure to the herbicide glufosinate ammonium (GLA) on offspring neuronal synapse formation in vitro. Cultured cerebral cortical neurons prepared from mouse embryos with maternal GLA exposure demonstrated impaired synapse formation induced by synaptic organizer neuroligin 1 (NLGN1)-coated beads. Conversely, the direct administration of GLA to the neuronal cultures exhibited negligible effect on the NLGN1-induced synapse formation. The comparison of the transcriptomes of cultured neurons from embryos treated with maternal GLA or vehicle and a subsequent bioinformatics analysis of differentially expressed genes (DEGs) identified "nervous system development," including "synapse," as the top-ranking process for downregulated DEGs in the GLA group. In addition, we detected lower densities of parvalbumin (Pvalb)-positive neurons at the postnatal developmental stage in the medial prefrontal cortex (mPFC) of offspring born to GLA-exposed dams. These results suggest that maternal GLA exposure induces synapse pathology, with alterations in the expression of genes that regulate synaptic development via an indirect pathway distinct from the effect of direct GLA action on neurons.

Modulation of vagal activity may help reduce neurodevelopmental damage in the offspring of mothers with pre-eclampsia

Maternal Immune Activation (MIA) has been linked to the pathogenesis of pre-eclampsia and adverse neurodevelopmental outcomes in the offspring, such as cognitive deficits, behavioral abnormalities, and mental disorders. Pre-eclampsia is associated with an activation of the immune system characterized by persistently elevated levels of proinflammatory cytokines, as well as a decrease in immunoregulatory factors. The Cholinergic Anti-inflammatory Pathway (CAP) may play a relevant role in regulating the maternal inflammatory response during pre-eclampsia and protecting the developing fetus from inflammation-induced damage. Dysregulation in the CAP has been associated with the clinical evolution of pre-eclampsia. Some studies suggest that therapeutic stimulation of this pathway may improve maternal and fetal outcomes in preclinical models of pre-eclampsia. Modulation of vagal activity influences the CAP, improving maternal hemodynamics, limiting the inflammatory response, and promoting the growth of new neurons, which enhances synaptic plasticity and improves fetal neurodevelopment. Therefore, we postulate that modulation of vagal activity may improve maternal and fetal outcomes in pre-eclampsia by targeting underlying immune dysregulation and promoting better fetal neurodevelopment. In this perspective, we explore the clinical and experimental evidence of electrical, pharmacological, physical, and biological stimulation mechanisms capable of inducing therapeutical CAP, which may be applied in pre-eclampsia to improve the mother's and offspring's quality of life.

Editorial for the Molecular Mechanisms in Neurodevelopmental Disorders Special Issue

Neurodevelopmental disorders are a group of neurological disorders that may give rise to delayed or impaired cognition, communication, adaptive behavior, and psychomotor skills [...].