Sex differences in neuronal systems function and behaviour: beyond a single diagnosis in autism spectrum disorders

Profiling clinical heterogeneity in Autism Spectrum Disorder at time of children's diagnosis: A cluster analysis from the ELENA cohort

BACKGROUND

Autism Spectrum Disorder (ASD) encompass a heterogeneous group of neurodevelopmental conditions characterized by deficits in social communication and repetitive behaviors. The rising prevalence of ASD highlights the urgent need for effective diagnostic and intervention strategies. However, the significant clinical, cognitive and etiological heterogeneity within ASD populations poses substantial challenges to these efforts.

AIMS

This study aimed to identify distinct ASD subtypes at time of diagnosis within the ELENA cohort by incorporating not only DSM-5 criteria but also measures of adaptive functioning and behavioral problems.

MATERIAL AND METHODS

Data from 458 children and adolescents with ASD were analyzed using hierarchical agglomerative clustering. Variables included autistic symptoms, intellectual quotient, adaptive behavior and behavioral problems. Clusters were identified based on these parameters, and post-hoc analyses were conducted to assess statistically significant differences in sex and age among the four clusters using Chi-square test and Student's t-tests.

RESULTS

Four distinct clusters were identified from the analysis: (1) High Autistic Symptom Severity with Lowest Behavioral Problems, (2) High Autistic Symptom Severity with High Behavioral Problems, (3) Low Autistic Symptom Severity with Highest Behavioral Problems and (4) Low Autistic Symptom Severity with low behavioral problems, while significant age differences were observed across clusters, no significant sex differences were found.

DISCUSSION

These clusters exhibited significant variability in adaptive functioning and behavioral problems, suggesting that DSM-5 criteria alone do not fully capture the complexity of ASD. The findings underscore the importance of incorporating measures of adaptive functioning and behavioral problems into ASD assessments and interventions. Future research should aim to validate these clusters in larger and more diverse populations and explore the integration of genetic and neuroimaging data to further refine the characterization of ASD subtypes. Additionally, longitudinal studies are needed to assess the stability and clinical relevance of these subtypes over time.

TRIAL REGISTRATION NUMBER

NCT02625116.

Prenatal exposure to valproic acid induces sex-specific alterations in rat cortical and hippocampal neuronal structure and function in vitro

There are substantial differences in the characteristics of males and females with an autism spectrum disorder (ASD), yet there is little knowledge surrounding the mechanistic underpinnings of these differences. The valproic acid (VPA) rodent model is based upon the human fetal valproate spectrum disorder, which is associated with increased risk of developing ASD. This model, which displays significant social, learning, and memory alterations, has therefore been widely used to further our understanding of specific biological features of ASD. However, to date, almost all of the studies employing this model have used male rodents. To fill this knowledge gap, we evaluated sex differences for neuronal activity, morphology, and glycogen synthase kinase-3 (GSK-3) signaling in primary cortical (CTX) and hippocampal (HIP) neurons prepared from rats exposed to VPA in utero. In vivo, sex-specific VPA-induced alterations in the frontal CTX transcriptome at birth were also determined. Overall, VPA induced more robust changes in neuronal function and structure in the CTX than in the HIP. Male- and female-derived primary CTX neurons from rats exposed to prenatal VPA had elevated activity and showed more disorganized firing. In the HIP, only the female VPA neurons showed elevated firing, while the male VPA neurons exhibited disorganized activity. Dendritic arborization of CTX neurons from VPA rats was less complex in both sexes, though this was more pronounced in the females. Conversely, both female and male HIP neurons from VPA rats showed elevated complexity distal to the soma. Female VPA CTX neurons also had an elevated number of dendritic spines. The relative activity of the α and β isoforms of GSK-3 were suppressed in both female and male VPA CTX neurons, with no changes in the HIP neurons. On postnatal day 0, alterations in CTX genes associated with neuropeptides (e.g., penk, pdyn) and receptors (e.g., drd1, adora2a) were seen in both sexes, though they were downregulated in females and upregulated in males. Together these findings suggest that substantial sex differences in neuronal structure and function in the VPA model may have relevance to the reported sex differences in idiopathic ASD.

Abnormalities in cerebellar subregions' volume and cerebellocerebral structural covariance in autism spectrum disorder

The cerebellum plays a crucial role in functions, including sensory-motor coordination, cognition, and emotional processing. Compared to the neocortex, the human cerebellum exhibits a protracted developmental trajectory. This delayed developmental timeline may lead to increased sensitivity of the cerebellum to external influences, potentially extending the vulnerability period for neurological disorders. Abnormal cerebellar development in individuals with autism has been confirmed, and these atypical cerebellar changes may affect the development of the neocortex. However, due to the heterogeneity of autism spectrum disorder (ASD), the regional changes in the cerebellum and cerebellocerebral structural relationship remain unknown. To address these issues, we utilized imaging methods optimized for the cerebellum and cerebrum on 817 individuals aged 5-18 years in the ABIDE II dataset. After FDR correction, significant differences between groups were found in the right crus II/VIIB and vermis VI-VII. Structural covariance analysis revealed enhanced structural covariance in individuals with autism between the cerebellum and parahippocampal gyrus, pars opercularis, and transverse temporal gyrus in the right hemisphere after FDR correction. Furthermore, the structural covariance between the cerebellum and some regions of the cerebrum varied across sexes. A significant increase in structural covariance between the cerebellum and specific subcortical structures was also observed in individuals with ASD. Our study found atypical patterns in the structural covariance between the cerebellum and cerebrum in individuals with autism, which suggested that the underlying pathological processes of ASD might concurrently affect these brain regions. This study provided insight into the potential of cerebellocerebral pathways as therapeutic targets for ASD.

Effects of dopamine receptor antagonists and radiation on mouse neural stem/progenitor cells

BACKGROUND

Dopamine receptor antagonists have recently been identified as potential anti-cancer agents in combination with radiation, and a first drug of this class is in clinical trials against pediatric glioma. Radiotherapy causes cognitive impairment primarily by eliminating neural stem/progenitor cells and subsequent loss of neurogenesis, along with inducing inflammation, vascular damage, and synaptic alterations. Here, we tested the combined effects of dopamine receptor antagonists and radiation on neural stem/progenitor cells.

METHODS

Using transgenic mice that report the presence of neural stem/progenitor cells through Nestin promoter-driven expression of EGFP, the effects of dopamine receptor antagonists alone or in combination with radiation on neural stem/progenitor cells were assessed in sphere-formation assays, extreme limiting dilution assays, flow cytometry and real-time PCR in vitro and in vivo in both sexes.

RESULTS

We report that hydroxyzine and trifluoperazine exhibited sex-dependent effects on murine newborn neural stem/progenitor cells in vitro. In contrast, amisulpride, nemonapride, and quetiapine, when combined with radiation, significantly increased the number of neural stem/progenitor cells in both sexes. In vivo, trifluoperazine showed sex-dependent effects on adult neural stem/progenitor cells, while amisulpride demonstrated significant effects in both sexes. Further, amisulpride increased sphere forming capacity and stem cell frequency in both sexes when compared to controls.

CONCLUSION

We conclude that a therapeutic window for dopamine receptor antagonists in combination with radiation potentially exists, making it a novel combination therapy against glioblastoma. Normal tissue toxicity following this treatment scheme likely differs depending on age and sex and should be taken into consideration when designing clinical trials.

Resting-state EEG patterns of preschool-aged boys with autism spectrum disorder: A pilot study

Defective cognition development during preschool years is believed to be linked with core symptoms of autism spectrum disorder (ASD). Neurophysiological research on mechanisms underly the cognitive disabilities of preschool-aged children with ASD is scarce currently. This pilot study aimed to compare the resting spectral EEG power of preschool-aged boys with ASD with their matched typically developing peers. Children in the ASD group demonstrated reduced central and posterior absolute delta (1-4 Hz) and enhanced frontal absolute beta (12-30 Hz) and gamma (30-45 Hz). The relative power of the ASD group was elevated in delta, theta (4-8 Hz), alpha (8-12 Hz), beta, and gamma bands as compared to the controls. The theta/beta ratio decreased in the frontal regions and enhanced at Cz and Pz electrodes in the ASD group. Correlations between the inhibition and metacognition indices of the behavior rating inventory of executive function-preschool version (BRIEF-P) and the theta/beta ratio for children of both groups were significant. In conclusion, the present study revealed atypical resting spectral characteristics of boys with ASD at preschool ages. Future large-sampled studies for the generalization of our findings and a better understanding of the relationships between brain oscillations and phenotypes of ASD are warranted.

Sex-specific and cell-specific regulation of ER stress and neuroinflammation after traumatic brain injury in juvenile mice

Endoplasmic reticulum (ER) stress and neuroinflammation play an important role in secondary brain damage after traumatic brain injury (TBI). Due to the complex brain cytoarchitecture, multiple cell types are affected by TBI. However, cell type-specific and sex-specific responses to ER stress and neuroinflammation remain unclear. Here we investigated differential regulation of ER stress and neuroinflammatory pathways in neurons and microglia during the acute phase post-injury in a mouse model of impact acceleration TBI in both males and females. We found that TBI resulted in significant weight loss only in males, and sensorimotor impairment and depressive-like behaviors in both males and females at the acute phase post-injury. By concurrently isolating neurons and microglia from the same brain sample of the same animal, we were able to evaluate the simultaneous responses in neurons and microglia towards ER stress and neuroinflammation in both males and females. We discovered that the ER stress and anti-inflammatory responses were significantly stronger in microglia, especially in female microglia, compared with the male and female neurons. Whereas the degree of phosphorylated-tau (pTau) accumulation was significantly higher in neurons, compared with the microglia. In conclusion, TBI resulted in behavioral deficits and cell type-specific and sex-specific responses to ER stress and neuroinflammation, and abnormal protein accumulation at the acute phase after TBI in immature mice.

MEF2C Hypofunction in GABAergic Cells Alters Sociability and Prefrontal Cortex Inhibitory Synaptic Transmission in a Sex-Dependent Manner

Background

Heterozygous mutations or deletions of MEF2C cause a neurodevelopmental disorder termed MEF2C haploinsufficiency syndrome (MCHS), characterized by autism spectrum disorder and neurological symptoms. In mice, global Mef2c heterozygosity has produced multiple MCHS-like phenotypes. MEF2C is highly expressed in multiple cell types of the developing brain, including GABAergic (gamma-aminobutyric acidergic) inhibitory neurons, but the influence of MEF2C hypofunction in GABAergic neurons on MCHS-like phenotypes remains unclear.

Methods

We employed GABAergic cell type-specific manipulations to study mouse Mef2c heterozygosity in a battery of MCHS-like behaviors. We also performed electroencephalography, single-cell transcriptomics, and patch-clamp electrophysiology and optogenetics to assess the impact of Mef2c haploinsufficiency on gene expression and prefrontal cortex microcircuits.

Results

Mef2c heterozygosity in developing GABAergic cells produced female-specific deficits in social preference and altered approach-avoidance behavior. In female, but not male, mice, we observed that Mef2c heterozygosity in developing GABAergic cells produced 1) differentially expressed genes in multiple cell types, including parvalbumin-expressing GABAergic neurons, 2) baseline and social-related frontocortical network activity alterations, and 3) reductions in parvalbumin cell intrinsic excitability and inhibitory synaptic transmission onto deep-layer pyramidal neurons.

Conclusions

MEF2C hypofunction in female, but not male, developing GABAergic cells is important for typical sociability and approach-avoidance behaviors and normal parvalbumin inhibitory neuron function in the prefrontal cortex of mice. While there is no apparent sex bias in autism spectrum disorder symptoms of MCHS, our findings suggest that GABAergic cell-specific dysfunction in females with MCHS may contribute disproportionately to sociability symptoms.

A cohort study of neurodevelopmental disorders and/or congenital anomalies using high resolution chromosomal microarrays in southern Brazil highlighting the significance of ASD

Chromosomal microarray (CMA) is the reference in evaluation of copy number variations (CNVs) in individuals with neurodevelopmental disorders (NDDs), such as intellectual disability (ID) and/or autism spectrum disorder (ASD), which affect around 3-4% of the world's population. Modern platforms for CMA, also include probes for single nucleotide polymorphisms (SNPs) that detect homozygous regions in the genome, such as long contiguous stretches of homozygosity (LCSH). These regions result from complete or segmental chromosomal homozygosis and may be indicative of uniparental disomy (UPD), inbreeding, population characteristics, as well as replicative DNA repair events. In this retrospective study, we analyzed CMA reading files requested by geneticists and neurologists for diagnostic purposes along with available clinical data. Our objectives were interpreting CNVs and assess the frequencies and implications of LCSH detected by Affymetrix CytoScan HD (41%) or 750K (59%) platforms in 1012 patients from the south of Brazil. The patients were mainly children with NDDs and/or congenital anomalies (CAs). A total of 206 CNVs, comprising 132 deletions and 74 duplications, interpreted as pathogenic, were found in 17% of the patients in the cohort and across all chromosomes. Additionally, 12% presented rare variants of uncertain clinical significance, including LPCNVs, as the only clinically relevant CNV. Within the realm of NDDs, ASD carries a particular importance, owing to its escalating prevalence and its growing repercussions for individuals, families, and communities. ASD was one clinical phenotype, if not the main reason for referral to testing, for about one-third of the cohort, and these patients were further analyzed as a sub-cohort. Considering only the patients with ASD, the diagnostic rate was 10%, within the range reported in the literature (8-21%). It was higher (16%) when associated with dysmorphic features and lower (7%) for "isolated" ASD (without ID and without dysmorphic features). In 953 CMAs of the whole cohort, LCSH (≥ 3 Mbp) were analyzed not only for their potential pathogenic significance but were also explored to identify common LCSH in the South Brazilians population. CMA revealed at least one LCSH in 91% of the patients. For about 11.5% of patients, the LCSH suggested consanguinity from the first to the fifth degree, with a greater probability of clinical impact, and in 2.8%, they revealed a putative UPD. LCSH found at a frequency of 5% or more were considered common LCSH in the general population, allowing us to delineate 10 regions as potentially representing ancestral haplotypes of neglectable clinical significance. The main referrals for CMA were developmental delay (56%), ID (33%), ASD (33%) and syndromic features (56%). Some phenotypes in this population may be predictive of a higher probability of indicating a carrier of a pathogenic CNV. Here, we present the largest report of CMA data in a cohort with NDDs and/or CAs from the South of Brazil. We characterize the rare CNVs found along with the main phenotypes presented by each patient and show the importance and usefulness of LCSH interpretation in CMA results that incorporate SNPs, as well as we illustrate the value of CMA to investigate CNV in ASD.

Oscillatory activity underlying cognitive performance in children and adolescents with autism: a systematic review

Autism spectrum disorder (ASD) is a neurodevelopmental condition that exhibits a widely heterogeneous range of social and cognitive symptoms. This feature has challenged a broad comprehension of this neurodevelopmental disorder and therapeutic efforts to address its difficulties. Current therapeutic strategies have focused primarily on treating behavioral symptoms rather than on brain psychophysiology. During the past years, the emergence of non-invasive brain stimulation techniques (NIBS) has opened alternatives to the design of potential combined treatments focused on the neurophysiopathology of neuropsychiatric disorders like ASD. Such interventions require identifying the key brain mechanisms underlying the symptomatology and cognitive features. Evidence has shown alterations in oscillatory features of the neural ensembles associated with cognitive functions in ASD. In this line, we elaborated a systematic revision of the evidence of alterations in brain oscillations that underlie key cognitive processes that have been shown to be affected in ASD during childhood and adolescence, namely, social cognition, attention, working memory, inhibitory control, and cognitive flexibility. This knowledge could contribute to developing therapies based on NIBS to improve these processes in populations with ASD.

Association of two variable number of tandem repeats in the monoamine oxidase A gene promoter with suicide completion: The present study and meta-analysis

BACKGROUND

One potential cause of suicide is serotonergic dysfunction. Sex differences have been reported to modulate the effects of serotonergic polymorphisms. Monoamine oxidase A (MAOA) is an enzyme that degrades serotonin and is located on the X chromosome. A previous study indicated that the upstream (u) variable number of tandem repeat (VNTR) in the MAOA gene promoter may be associated with suicide. However, a meta-analysis showed that this polymorphism may not be related to suicide. According to a recent study, compared with the uVNTR, the distal (d)VNTR and the haplotypes of the two VNTRs modulate MAOA expression.

METHODS

We examined the two VNTRs in the MAOA gene promoter in 1007 subjects who committed suicide and 844 healthy controls. We analyzed the two VNTRs using fluorescence-based polymerase chain reaction assays. We conducted a meta-analysis for the two VNTRs to update it.

RESULTS

Our results demonstrated that neither the genotype-based associations nor allele/haplotype frequencies of the two VNTRs were significantly associated with suicide. In the meta-analysis, we did not indicate relationships between uVNTR and suicide nor did we identify articles analyzing dVNTR in suicide.

CONCLUSION

Overall, we did not find a relationship between the two VNTRs in the MAOA promoter and suicide completion; thus, warranting further studies are required.

Complexity of Sex Differences and Their Impact on Alzheimer's Disease

Sex differences are present in brain morphology, sex hormones, aging processes and immune responses. These differences need to be considered for proper modelling of neurological diseases with clear sex differences. This is the case for Alzheimer's disease (AD), a fatal neurodegenerative disorder with two-thirds of cases diagnosed in women. It is becoming clear that there is a complex interplay between the immune system, sex hormones and AD. Microglia are major players in the neuroinflammatory process occurring in AD and have been shown to be directly affected by sex hormones. However, many unanswered questions remain as the importance of including both sexes in research studies has only recently started receiving attention. In this review, we provide a summary of sex differences and their implications in AD, with a focus on microglia action. Furthermore, we discuss current available study models, including emerging complex microfluidic and 3D cellular models and their usefulness for studying hormonal effects in this disease.

Risk prediction of autism spectrum disorder behaviors among children based on blood elements by nomogram: A cross-sectional study in Xinjiang from 2018 to 2019

BACKGROUND

Changes of toxic metals and essential elements during childhood may be the risk factor of autism spectrum disorder (ASD). This research established an accurate personalized predictive model of ASD behaviors among children by using the blood element detection index of children in Xinjiang, China.

METHODS

A total of 1537 children (240 ASD behavior children and 1297 non-ASD behavior children) aged 0-7 were collected from September 2018 to September 2019 in Urumqi Children's Hospital and the health management institute of Xinjiang Medical University. For measuring the copper (Cu), zinc (Zn), magnesium (Mg), iron (Fe), calcium (Ca), lead (Pb), and cadmium (Cd), 80 μL of blood was taken from each participant's ring finger. Univariate logistic regression analysis was used to select predictors, then the multivariate logistic regression was used to establish the predictive model. The discriminability, calibration and clinical validity of the model were evaluated by the receiver operating characteristic (ROC) curve, Hosmer-Lemeshow test and decision curve analysis (DCA).

RESULTS

Gender, concentrations of Pb, Ca and Zn in children's blood specimens were found to be the independent risk factors of ASD behaviors and were used to develop the nomogram model. The area under the ROC curve (AUC) in the development group (AUC = 0.778) and the validation group (AUC = 0.775) showed the model had discrimination ability. The calibration curve indicated the model was accurate, and the DCA proved its clinical application value.

CONCLUSION

The nomogram model can be used as a reliable tool to predict the risk of ASD behaviors among children.

Granulocyte Colony-Stimulating Factor Has a Sex-Dependent Positive Effect in the Maternal Immune Activation-Induced Autism Model

OBJECTIVE

The medical intervention for autism spectrum disorder (ASD) is restricted to ameliorating comorbid situations. Granulocyte colony-stimulating factor (G-CSF) is a growth factor that enhances the proliferation, differentiation and survival of hematopoietic progenitor cells. In the present study, we aimed to investigate the effects of G-CSF in a maternal immune activation-induced autism model.

METHODS

Sixteen female and 6 male Wistar adult rats were included in the study. After 21 days, forty-eight littermates (8 male controls, 8 female controls, 16 male lipopolysaccharide (LPS)-exposed rats and 16 female LPS-exposed rats) were divided into groups. Sixteen male LPS-exposed and 16 female LPS-exposed rats were divided into saline and G-CSF treatment groups.

RESULTS

In male rats, the LPS-exposed group was found to have significantly higher levels of TNF-α, IL-2, and IL-17 than the LPS-exposed G-CSF group. Levels of nerve growth factor, brain PSD-95 and brain GAD67 were higher in the LPS-exposed G-CSF group than in the LPS-exposed group in male rats. In female rats, brain NGF levels were similar between groups. There was no difference between groups in terms of brain GAD 67 levels. Brain PSD-95 levels were higher in the control group than in both the LPS-exposed and LPS-exposed G-CSF groups in female rats. Both neuronal CA1 and neuronal CA2 levels were lower, and the GFAP immunostaining index (CA1) and GFAP immunostaining index (CA3) were higher in the LPS-exposed group than in the LPS-exposed G-CSF group in male rats. However, neuronal count CA1 and Neuronal count CA3 values were found to be similar between groups in female rats.

CONCLUSIONS

The present research is the first to demonstrate the beneficial effects of G-CSF on core symptoms of ASD experimentally depending on male sex. G-CSF can be a good candidate for ameliorating the core symptoms of ASD without serious side effects in males.

Theta and gamma oscillatory dynamics in mouse models of Alzheimer's disease: A path to prospective therapeutic intervention

Understanding the neural basis of cognitive deficits, a key feature of Alzheimer's disease (AD), is imperative for achieving the therapy of the disease. Rhythmic oscillatory activities in neural systems are a fundamental mechanism for diverse brain functions, including cognition. In several neurological conditions like AD, aberrant neural oscillations have been shown to play a central role. Furthermore, manipulation of brain oscillations in animals has confirmed their impact on cognition and disease. In this article, we review the evidence from mouse models that shows how synchronized oscillatory activity is intricately linked to AD machinery. We primarily focus on recent reports showing abnormal oscillatory activities at theta and gamma frequencies in AD condition and their influence on cellular disturbances and cognitive impairments. A thorough comprehension of the role that neuronal oscillations play in AD pathology should pave the way to therapeutic interventions that can curb the disease.