Investigation of sex differences in the expression of RORA and its transcriptional targets in the brain as a potential contributor to the sex bias in autism

Mechanistic perspective on the actions of vitamin a in autism spectrum disorder etiology

Vitamin A (VA) has many functions in the body, some of which are key for the development and functioning of the nervous system, while some others might indirectly influence neural function. Both hypovitaminosis and hypervitaminosis A can lead to clinical manifestations of concern for individuals and for general global health. Scientific evidence on the link between VA and autism spectrum disorder (ASD) is growing, with some clinical studies and accumulating results obtained from basic research using cellular and animal models. Remarkably, it has been shown that VA deficiency can exacerbate autistic symptomatology. In turn, VA supplementation has been shown to be able to improve autistic symptomatology in selected groups of individuals with ASD. However, it is important to recognize that ASD is a highly heterogeneous condition. Therefore, it is important to clarify how and when VA supplementation can be of benefit for affected individuals. Here we delve into the relationship between VA and ASD, discussing clinical observations and mechanistic insights obtained from research on selected autistic syndromes and laboratory models to advance in defining how the VA signaling pathway can be exploited for treatment of ASD.

Androgen levels in autism spectrum disorders: a systematic review and meta-analysis

Background

Accumulating evidence suggests that the autism spectrum disorder (ASD) population exhibits altered hormone levels, including androgens. However, studies on the regulation of androgens, such as testosterone and dehydroepiandrosterone (DHEA), in relation to sex differences in individuals with ASD are limited and inconsistent. We conducted the systematic review with meta-analysis to quantitatively summarise the blood, urine, or saliva androgen data between individuals with ASD and controls.

Methods

A systematic search was conducted for eligible studies published before 16 January 2023 in six international and two Chinese databases. We computed summary statistics with a random-effects model. Publication bias was assessed using funnel plots and heterogeneity using I2 statistics. Subgroup analysis was performed by age, sex, sample source, and measurement method to explain the heterogeneity.

Results

17 case-control studies (individuals with ASD, 825; controls, 669) were assessed. Androgen levels were significantly higher in individuals with ASD than that in controls (SMD: 0.27, 95% CI: 0.06-0.48, P=0.01). Subgroup analysis showed significantly elevated levels of urinary total testosterone, urinary DHEA, and free testosterone in individuals with ASD. DHEA level was also significantly elevated in males with ASD.

Conclusion

Androgen levels, especially free testosterone, may be elevated in individuals with ASD and DHEA levels may be specifically elevated in males.

Giftedness and atypical sexual differentiation: enhanced perceptual functioning through estrogen deficiency instead of androgen excess

Syndromic autism spectrum conditions (ASC), such as Klinefelter syndrome, also manifest hypogonadism. Compared to the popular Extreme Male Brain theory, the Enhanced Perceptual Functioning model explains the connection between ASC, savant traits, and giftedness more seamlessly, and their co-emergence with atypical sexual differentiation. Overexcitability of primary sensory inputs generates a relative enhancement of local to global processing of stimuli, hindering the abstraction of communication signals, in contrast to the extraordinary local information processing skills in some individuals. Weaker inhibitory function through gamma-aminobutyric acid type A (GABAA) receptors and the atypicality of synapse formation lead to this difference, and the formation of unique neural circuits that process external information. Additionally, deficiency in monitoring inner sensory information leads to alexithymia (inability to distinguish one's own emotions), which can be caused by hypoactivity of estrogen and oxytocin in the interoceptive neural circuits, comprising the anterior insular and cingulate gyri. These areas are also part of the Salience Network, which switches between the Central Executive Network for external tasks and the Default Mode Network for self-referential mind wandering. Exploring the possibility that estrogen deficiency since early development interrupts GABA shift, causing sensory processing atypicality, it helps to evaluate the co-occurrence of ASC with attention deficit hyperactivity disorder, dyslexia, and schizophrenia based on phenotypic and physiological bases. It also provides clues for understanding the common underpinnings of these neurodevelopmental disorders and gifted populations.

The role and impact of abnormal vitamin levels in autism spectrum disorders

The prevalence of autism spectrum disorder (ASD), a neurodevelopmental disorder with a predominance of social behavioral disorders, has increased dramatically in various countries in recent decades. The interplay between genetic and environmental factors is believed to underlie ASD pathogenesis. Recent analyses have shown that abnormal vitamin levels in early life are associated with an increased risk of autism. As essential substances for growth and development, vitamins have been shown to have significant benefits for the nervous and immune systems. However, it is unknown whether certain vitamin types influence the emergence or manifestation of ASD symptoms. Several studies have focused on vitamin levels in children with autism, and neurotypical children have provided different insights into the types of vitamins and their intake. Here, we review the mechanisms and significance of several vitamins (A, B, C, D, E, and K) that are closely associated with the development of ASD in order to prevent, mitigate, and treat ASD. Efforts have been made to discover and develop new indicators for nutritional assessment of children with ASD to play a greater role in the early detection of ASD and therapeutic remission after diagnosis.

Sex Differences in Brain Disorders

A remarkable feature of the brain is its sexual dimorphism. Sexual dimorphism in brain structure and function is associated with clinical implications documented previously in healthy individuals but also in those who suffer from various brain disorders. Sex-based differences concerning some features such as the risk, prevalence, age of onset, and symptomatology have been confirmed in a range of neurological and neuropsychiatric diseases. The mechanisms responsible for the establishment of sex-based differences between men and women are not fully understood. The present paper provides up-to-date data on sex-related dissimilarities observed in brain disorders and highlights the most relevant features that differ between males and females. The topic is very important as the recognition of disparities between the sexes might allow for the identification of therapeutic targets and pharmacological approaches for intractable neurological and neuropsychiatric disorders.

Transcript levels of 4 genes in umbilical cord blood are predictive of later autism development: a longitudinal follow-up study

BACKGROUND

Over recent decades, autism spectrum disorder (ASD) has been of increasing epidemiological importance, given the substantial increase in its prevalence; at present, clinical diagnosis is possible only after 2 years of age. In this study, we sought to develop a potential predictive model for ASD screening.

METHODS

We conducted a longitudinal follow-up study of newborns over 3 years. We measured transcript levels of 4 genes (superoxide dismutase-2 [SOD2], retinoic acid-related orphan receptor-α [RORA], G protein-coupled estrogen receptor-1 [GPER], progesterone receptor [PGR]), 2 oxidative stress markers and epigenetic marks at the RORA promoter in case-control umbilical cord blood mononuclear cell (UCBMC) samples.

RESULTS

We followed 2623 newborns; we identified 41 children with ASD, 63 with delayed development and 2519 typically developing children. We matched the 41 children with ASD to 41 typically developing children for UCBMC measurements. Our results showed that children with ASD had significantly higher levels of H3K9me3 histone modifications at the RORA promoter and oxidative stress in UCBMC than typically developing children; children with delayed development showed no significant differences. Children with ASD had significantly lower expression of SOD2, RORA and GPER, but higher PGR expression than typically developing children. We established a model based on these 4 candidate genes, and achieved an area under the curve of 87.0% (standard deviation 3.9%) with a sensitivity of 1.000 and specificity of 0.854 to predict ASD in UCBMC.

LIMITATIONS

Although the gene combinations produced a good pass/fail cut-off value for ASD evaluation, relatively few children in our study sample had ASD.

CONCLUSION

The altered gene expression in UCBMC can predict later autism development, possibly providing a predictive model for ASD screening immediately after birth.

Neuroprotective role for RORA in Parkinson's disease revealed by analysis of post-mortem brain and a dopaminergic cell line

Parkinson's disease (PD) is almost twice as prevalent in men, which has largely been attributed to neuroprotective effect of oestradiol in women. RORA (retinoic acid receptor-related orphan receptor alpha) regulates the transcription of central aromatase, the enzyme responsible for local oestradiol synthesis, simultaneously, RORA expression is regulated by sex hormones. Moreover, RORA protects neurones against oxidative stress, a key mechanism contributing to the loss of dopaminergic neurones in PD. Therefore, we hypothesized that there would be sex differences in RORA expression in the substantia nigra pars compacta (SNpc), which could contribute to sex differences observed in PD prevalence and pathogenesis. In a case control study, qPCR and western blot analyses were used to quantify gene and protein expression in the SNpc of post-mortem brains (n = 14 late-stage PD and 11 age and sex matched controls). The neuroprotective properties of a RORA agonist were then investigated directly using a cell culture toxin-based model of PD coupled with measures of viability, mitochondrial function and apoptosis. RORA was expressed at significantly higher levels in the SNpc from control females' brains compared to males. In PD, we found a significant increase in SNpc RORA expression in male PD compared to female PD. Treatment with a RORA agonist showed a significant neuroprotection in our cell culture model of PD and revealed significant effects on intracellular factors involved in neuronal survival and demise. This study is the first to demonstrate a sex specific pattern of RORA protein and gene expression in the SNpc of controls post-mortem human brains, and to show that this is differentially altered in male and female PD subjects, thus supporting a role for RORA in sex-specific aspects of PD. Furthermore, our in vitro PD model indicates mechanisms whereby a RORA agonist exerts its neuroprotective effect, thereby highlighting the translational potential for RORA ligands in PD.

G protein-coupled estrogen receptor (GPER) selective agonist G1 attenuates the neurobehavioral, molecular and biochemical alterations induced in a valproic acid rat model of autism

AIMS

Autism Spectrum Disorder (ASD) is a neurodevelopmental disorder with a rising prevalence in boys rather than girls. G protein-coupled estrogen receptor (GPER) activation by its agonist G1 showed a neuroprotective effect, similar to estradiol. The present study aimed to examine the potential of the selective GPER agonist G1 therapy on the behavioral, histopathological, biochemical, and molecular alterations induced in a valproic acid (VPA)-rat model of autism.

MAIN METHODS

VPA (500 mg/kg) was intraperitoneally administered to female Wistar rats (on gestational day 12.5) to induce the VPA-rat model of autism. The male offspring were intraperitoneally administered with G1 (10 and 20 μg/kg) for 21 days. After the treatment process, rats performed behavioral assessments. Then, sera and hippocampi were collected for biochemical and histopathological examinations and gene expression analysis.

KEY FINDINGS

GPER agonist G1 attenuated behavioral deficits, including hyperactivity, declined spatial memory and social preferences, anxiety, and repetitive behavior in VPA rats. G1 improved neurotransmission and reduced oxidative stress and histological alteration in the hippocampus. G1 reduced serum free T levels and interleukin-1β and up-regulated GPER, RORα, and aromatase gene expression levels in the hippocampus.

SIGNIFICANCE

The present study suggests that activation of GPER by its selective agonist G1 altered the derangements induced in a VPA-rat model of autism. G1 normalized free T levels via up-regulation of hippocampal RORα and aromatase gene expression. G1 provoked estradiol neuroprotective functions via up-regulation of hippocampal GPER expression. The G1 treatment and GPER activation provide a promising therapeutic approach to counteract the autistic-like symptoms.

Epigenetic Gene-Regulatory Loci in Alu Elements Associated with Autism Susceptibility in the Prefrontal Cortex of ASD

Alu elements are transposable elements that can influence gene regulation through several mechanisms; nevertheless, it remains unclear whether dysregulation of Alu elements contributes to the neuropathology of autism spectrum disorder (ASD). In this study, we characterized transposable element expression profiles and their sequence characteristics in the prefrontal cortex tissues of ASD and unaffected individuals using RNA-sequencing data. Our results showed that most of the differentially expressed transposable elements belong to the Alu family, with 659 loci of Alu elements corresponding to 456 differentially expressed genes in the prefrontal cortex of ASD individuals. We predicted cis- and trans-regulation of Alu elements to host/distant genes by conducting correlation analyses. The expression level of Alu elements correlated significantly with 133 host genes (cis-regulation, adjusted p < 0.05) associated with ASD as well as the cell survival and cell death of neuronal cells. Transcription factor binding sites in the promoter regions of differentially expressed Alu elements are conserved and associated with autism candidate genes, including RORA. COBRA analyses of postmortem brain tissues showed significant hypomethylation in global methylation analyses of Alu elements in ASD subphenotypes as well as DNA methylation of Alu elements located near the RNF-135 gene (p < 0.05). In addition, we found that neuronal cell density, which was significantly increased (p = 0.042), correlated with the expression of genes associated with Alu elements in the prefrontal cortex of ASD. Finally, we determined a relationship between these findings and the ASD severity (i.e., ADI-R scores) of individuals with ASD. Our findings provide a better understanding of the impact of Alu elements on gene regulation and molecular neuropathology in the brain tissues of ASD individuals, which deserves further investigation.

Sex differences in antioxidant defence and the regulation of redox homeostasis in physiology and pathology

Reactive oxygen species (ROS) is a term that defines a group of unstable compounds derived from exogenous sources or endogenous metabolism. Under physiological conditions, low levels of ROS play a key role in the regulation of signal transduction- or transcription-mediated cellular responses. In contrast, excessive and uncontrolled loading of ROS results in a pathological state known as oxidative stress (OS), a leading contributor to aging and a pivotal factor for the onset and progression of many disorders. Evolution has endowed cells with an antioxidant system involved in stabilizing ROS levels to a specific threshold, preserving ROS-induced signalling function and limiting negative side effects. In mammals, a great deal of evidence indicates that females defence against ROS is more proficient than males, determining a longer lifespan and lower incidence of most chronic diseases. In this review, we will summarize the most recent sex-related differences in the regulation of redox homeostasis. We will highlight the peculiar aspects of the antioxidant defence in sex-biased diseases whose onset or progression is driven by OS, and we will discuss the molecular, genetic, and evolutionary determinants of female proficiency to cope with ROS.

Investigation of autism-related transcription factors underlying sex differences in the effects of bisphenol A on transcriptome profiles and synaptogenesis in the offspring hippocampus

BACKGROUND

Bisphenol A (BPA) has been linked to susceptibility to autism spectrum disorder (ASD). Our recent studies have shown that prenatal BPA exposure disrupted ASD-related gene expression in the hippocampus, neurological functions, and behaviors associated with ASD in a sex-specific pattern. However, the molecular mechanisms underlying the effects of BPA are still unclear.

METHODS

Transcriptome data mining and molecular docking analyses were performed to identify ASD-related transcription factors (TFs) and their target genes underlying the sex-specific effects of prenatal BPA exposure. Gene ontology analysis was conducted to predict biological functions associated with these genes. The expression levels of ASD-related TFs and targets in the hippocampus of rat pups prenatally exposed to BPA were measured using qRT-PCR analysis. The role of the androgen receptor (AR) in BPA-mediated regulation of ASD candidate genes was investigated using a human neuronal cell line stably transfected with AR-expression or control plasmid. Synaptogenesis, which is a function associated with genes transcriptionally regulated by ASD-related TFs, was assessed using primary hippocampal neurons isolated from male and female rat pups prenatally exposed to BPA.

RESULTS

We found that there was a sex difference in ASD-related TFs underlying the effects of prenatal BPA exposure on the transcriptome profiles of the offspring hippocampus. In addition to the known BPA targets AR and ESR1, BPA could directly interact with novel targets (i.e., KDM5B, SMAD4, and TCF7L2). The targets of these TFs were also associated with ASD. Prenatal BPA exposure disrupted the expression of ASD-related TFs and targets in the offspring hippocampus in a sex-dependent manner. Moreover, AR was involved in the BPA-mediated dysregulation of AUTS2, KMT2C, and SMARCC2. Prenatal BPA exposure altered synaptogenesis by increasing synaptic protein levels in males but not in females, but the number of excitatory synapses was increased in female primary neurons only.

CONCLUSIONS

Our findings suggest that AR and other ASD-related TFs are involved in sex differences in the effects of prenatal BPA exposure on transcriptome profiles and synaptogenesis in the offspring hippocampus. These TFs may play an essential role in an increased ASD susceptibility associated with endocrine-disrupting chemicals, particularly BPA, and the male bias of ASD.

Exome-wide analysis identify multiple variations in olfactory receptor genes (OR12D2 and OR5V1) associated with autism spectrum disorder in Saudi females

Background

Autism Spectrum Disorder (ASD) is a multifactorial, neurodevelopmental disorder, characterized by deficits in communication, restricted and repetitive behaviors. ASD is highly heritable in Saudi Arabia; indecencies of affected individuals are increasing.

Objectives

To identify the most significant genes and SNPs associated with the increased risk of ASD in Saudi females to give an insight for early diagnosis.

Methods

Pilot case-control study mostly emphasized on the significant SNPs and haplotypes contributing to Saudi females with ASD patients (n = 22) compared to controls (n = 51) without ASD. With the use of allelic association analysis tools, 243,345 SNPs were studied systematically and classified according to their significant association. The significant SNPs and their genes were selected for further investigation for mapping of ASD candidate causal variants and functional impact.

Results

In females, five risk SNPs at p ≤ 2.32 × 10^-05 was identified in association with autism. The most significant exonic variants at chromosome 6p22.1 with olfactory receptor genes (OR12D2 and OR5V1) clustered with high linkage disequilibrium through haplotyping analysis. Comparison between highly associated genes (56 genes) of male and female autistic patients with female autistic samples revealed that 39 genes are unique biomarkers for Saudi females with ASD.

Conclusion

Multiple variations in olfactory receptor genes (OR5V1 and OR12D2) and single variations on SPHK1, PLCL2, AKAP9 and LOC107984893 genes are contributing to ASD in females of Arab origin. Accumulation of these multiple predisposed coding SNPs can increase the possibility of developing ASD in Saudi females.

Prenatal Sex Hormone Exposure Is Associated with the Development of Autism Spectrum Disorder

Sexual differentiation is a major developmental process. Sex differences resulting from sexual differentiation have attracted the attention of researchers. Unraveling what contributes to and underlies sex differences will provide valuable insights into the development of neurodevelopmental disorders that exhibit sex biases. Autism spectrum disorder (ASD) is a neurodevelopmental disorder that affects an individual's social interaction and communication abilities, and its male preponderance has been consistently reported in clinical studies. The etiology of male preponderance remains unclear, but progress has been made in studying prenatal sex hormone exposure. The present review examined studies that focused on the association between prenatal testosterone exposure and ASD development, as well as sex-specific behaviors in individuals with ASD. This review also included studies on maternal immune activation-induced developmental abnormalities that also showed striking sex differences in offspring and discussed its possible interacting roles in ASD so as to present a potential approach for future studies on sex biases in ASD.

Cerebellum and neurodevelopmental disorders: RORα is a unifying force

Errors of cerebellar development are increasingly acknowledged as risk factors for neuro-developmental disorders (NDDs), such as attention deficit hyperactivity disorder (ADHD), autism spectrum disorder (ASD), and schizophrenia. Evidence has been assembled from cerebellar abnormalities in autistic patients, as well as a range of genetic mutations identified in human patients that affect the cerebellar circuit, particularly Purkinje cells, and are associated with deficits of motor function, learning and social behavior; traits that are commonly associated with autism and schizophrenia. However, NDDs, such as ASD and schizophrenia, also include systemic abnormalities, e.g., chronic inflammation, abnormal circadian rhythms etc., which cannot be explained by lesions that only affect the cerebellum. Here we bring together phenotypic, circuit and structural evidence supporting the contribution of cerebellar dysfunction in NDDs and propose that the transcription factor Retinoid-related Orphan Receptor alpha (RORα) provides the missing link underlying both cerebellar and systemic abnormalities observed in NDDs. We present the role of RORα in cerebellar development and how the abnormalities that occur due to RORα deficiency could explain NDD symptoms. We then focus on how RORα is linked to NDDs, particularly ASD and schizophrenia, and how its diverse extra-cerebral actions can explain the systemic components of these diseases. Finally, we discuss how RORα-deficiency is likely a driving force for NDDs through its induction of cerebellar developmental defects, which in turn affect downstream targets, and its regulation of extracerebral systems, such as inflammation, circadian rhythms, and sexual dimorphism.

Qishen Yiqi dropping pills improve cardiomyocyte hypertrophy via the lncRNA TINCR/miR-193b-3p/RORA axis

BACKGROUND

This study was designed to explore the therapeutic effect and mechanism of action of Qishen Yiqi dropping pills (QYDP) in chronic heart failure (CHF) via a long non-coding RNA (lncRNA)-microRNA (miRNA)-messenger RNA (mRNA) axis. Here, the mechanism of action of the lncRNA terminal differentiation-induced non-coding RNA (TINCR), miR-193b-3p, and RAR-related orphan receptor A (RORA) mRNA was analyzed in an angiotensin (Ang) II-induced H9C2 cardiomyocyte hypertrophy model treated with QYDP.

METHODS

Reverse transcription-quantitative polymerase chain reaction (RT-qPCR) was used to analyze the gene expression changes of lncRNA, miRNA, and mRNA in H9C2 induced by QYDP on Ang II. The Gene Expression Omnibus (GEO) was used to analyze differentially expressed genes (DEGs) potentially affecting CHF progression. Cell Counting Kit-8 (CCK-8) was used to analyze the effect of QYDP on the proliferation of H9C2, RNA pull-down was used to analyze the binding of lncRNA and miRNA, and dual luciferase was used to analyze the targeting of miRNA and lncRNA or mRNA.

RESULTS

Ang II induced TINCR and RORA downregulation, miR-193b-3p upregulation, and hypertrophy in the H9C2 cardiomyocytes, which were alleviated by QYDP. In contrast, TINCR inhibition reversed the effects of QYDP by increasing miR-193b-3p expression and downregulating RORA expression. According to subsequent double luciferase and RNA pull-down experiments, TINCR adsorbed miR-193b-3p by acting as a competitive endogenous RNA sponge and miR-193b-3p directly targeted RORA. Lastly, we showed that the Ang-II-induced inhibition of TINCR and RORA expression and promotion of cardiac hypertrophy were both reversed by a TINCR overexpression plasmid (ov-TINCR), whereas the effects of ov-TINCR were suppressed by a miR-193b-3p mimic.

CONCLUSIONS

Administration of QYDP improves Ang II-induced H9C2 cardiomyocyte hypertrophy and increase cell proliferation rate through the TINCR/miR-193b-3p/RORA axis.

Regulation of Circadian Genes Nr1d1 and Nr1d2 in Sex-Different Manners during Liver Aging

Background: Circadian rhythm is associated with the aging process and sex differences; however, how age and sex can change circadian regulation systems remains unclear. Thus, we aimed to evaluate age- and sex-related changes in gene expression and identify sex-specific target molecules that can regulate aging. Methods: Rat livers were categorized into four groups, namely, young male, old male, young female, and old female, and the expression of several genes involved in the regulation of the circadian rhythm was confirmed by in silico and in vitro studies. Results: Gene Ontology and the Kyoto Encyclopedia of Genes and Genomes pathway enrichment analyses showed that the expression of genes related to circadian rhythms changed more in males than in females during liver aging. In addition, differentially expressed gene analysis and quantitative real-time polymerase chain reaction/western blotting analysis revealed that Nr1d1 and Nr1d2 expression was upregulated in males during liver aging. Furthermore, the expression of other circadian genes, such as Arntl, Clock, Cry1/2, Per1/2, and Rora/c, decreased in males during liver aging; however, these genes showed various gene expression patterns in females during liver aging. Conclusions: Age-related elevation of Nr1d1/2 downregulates the expression of other circadian genes in males, but not females, during liver aging. Consequently, age-related upregulation of Nr1d1/2 may play a more crucial role in the change in circadian rhythms in males than in females during liver aging.

Elevated exposures to persistent endocrine disrupting compounds impact the sperm methylome in regions associated with autism spectrum disorder

Environmental exposures to endocrine disrupting compounds (EDCs) such as the organochlorines have been linked with various diseases including neurodevelopmental disorders. Autism spectrum disorder (ASD) is a highly complex neurodevelopmental disorder that is considered strongly genetic in origin due to its high heritability. However, the rapidly rising prevalence of ASD suggests that environmental factors may also influence risk for ASD. In the present study, whole genome bisulfite sequencing was used to identify genome-wide differentially methylated regions (DMRs) in a total of 52 sperm samples from a cohort of men from the Faroe Islands (Denmark) who were equally divided into high and low exposure groups based on their serum levels of the long-lived organochlorine 1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene (DDE), a primary breakdown product of the now banned insecticide dichlorodiphenyltrichloroethane (DDT). Aside from being considered a genetic isolate, inhabitants of the Faroe Islands have a native diet that potentially exposes them to a wide range of seafood neurotoxicants in the form of persistent organic pollutants (POPs). The DMRs were mapped to the human genome using Bismark, a 3-letter aligner used for methyl-seq analyses. Gene ontology, functional, and pathway analyses of the DMR-associated genes showed significant enrichment for genes involved in neurological functions and neurodevelopmental processes frequently impacted by ASD. Notably, these genes also significantly overlap with autism risk genes as well as those previously identified in sperm from fathers of children with ASD in comparison to that of fathers of neurotypical children. These results collectively suggest a possible mechanism involving altered methylation of a significant number of neurologically relevant ASD risk genes for introducing epigenetic changes associated with environmental exposures into the sperm methylome. Such changes may provide the potential for transgenerational inheritance of ASD as well as other disorders.

Androgens Tend to Be Higher, but What about Altered Progesterone Metabolites in Boys and Girls with Autism?

Background: Evidence exists that steroid hormones are altered in individuals with autism, especially androgens. Despite lower prevalence in girls than boys, evidence of potential alterations in progesterone metabolites is sparse, so the aim of this study was to elucidate different progesterone metabolites in affected children with autism versus healthy controls. Material and Methods: Circadian urine samples from 48 boys and 16 girls with autism spectrum disorders and a matched case−control group were analysed for progesterone metabolites by gas chromatography−mass spectrometry and normalised for creatinine excretion. Results: In boys with autism, the majority of progesterone metabolites were reduced, such as progesterone, 6a-OH-3a5b-TH-progesterone, or 20a-DH-progesterone (p < 0.01 for all). In girls with autism, a similar pattern of reduction in progesterone metabolites was detected; however, potentially due to the relatively small sample, this pattern was only detectable on the level of a trend. Discussion: As stated, androgen levels are higher in boys and girls with autism, but evidence for progesterone metabolites is much sparser. The pattern of a decrease in progesterone metabolites suggests the existence of an altered routing of steroid metabolites, probably in combination with a dysregulation of the HPAG axis. As, recently, increased CYP17A1 activity has been suggested, the stronger routing towards androgens is further implied in line with our findings of lower progesterone concentrations in boys and girls with autism than healthy controls.

How Is CYP17A1 Activity Altered in Autism? A Pilot Study to Identify Potential Pharmacological Targets

Background: Increasing evidence exists that higher levels of androgens can be found in individuals with autism. Evidence yields to a susceptible role of Cytochrome P450 17A1 (CYP17A1) with its catalyzation of the two distinct types of substrate oxidation by a hydroxylase activity (17-alpha hydroxylase) and C17/20 lyase activity. However, to what extent steps are altered in affected children with autism versus healthy controls remains to be elucidated. Methods: Urine samples from 48 boys with autism (BMI 19.1 ± 0.6 kg/m², age 14.2 ± 0.5 years) and a matched cohort of 48 healthy boys (BMI 18.6 ± 0.3 kg/m², 14.3 ± 0.5 years) as well as 16 girls with autism (BMI 17.5 ± 0.7 kg/m², age 13.8 ± 1.0 years) and a matched cohort of 16 healthy girls (BMI 17.2 ± 0.8 kg/m², age 13.2 ± 0.8 years) were analyzed for steroid hormone metabolites by gas chromatography-mass spectrometry. Results: The activity of 17-alpha Hydroxylase increased by almost 50%, whereas activity of 17/20 Lyase activity increased by around 150% in affected children with autism. Furthermore, the concentration of Cortisol was higher as compared to the average increase of the three metabolites TH-Corticosterone, 5α-TH-Corticosterone and TH-11β-DH-Corticosterone, indicating, in addition, a stimulation by the CRH-ACTH system despite a higher enzymatic activity. Discussion: As it was shown that oxidative stress increases the 17/20-lyase activity via p38α, a link between higher steroid hormone levels and oxidative stress can be established. However, as glucocorticoid as well as androgen metabolites showed higher values in subjects affected with autism as compared to healthy controls, the data indicate, despite higher CYP17A1 activity, the presence of increased substrate availability in line with the Cholesterol theory of autism.

Vitamin A Status Is More Commonly Associated With Symptoms and Neurodevelopment in Boys With Autism Spectrum Disorders-A Multicenter Study in China

Background

Autism spectrum disorder (ASD) is a neurodevelopmental disorder, and show a striking male bias in prevalence. Vitamin A (VA) is essential for brain development, and abnormalities in its metabolite retinoic acid are associated with the pathophysiology of ASD. This national multicenter study was conducted to investigate the relationship between serum VA level and core symptoms in ASD children and whether there are still sex differences.

Method

A total of 1,300 children with ASD and 1,252 typically-developing (TD) controls aged 2-7 years old from 13 cities in China were enrolled in this study. The symptoms of children with ASD were evaluated by the Autism Behavior Checklist (ABC), Social Responsiveness Scale (SRS), and Childhood autism rating scale (CARS). The neurodevelopmental level of the children was evaluated with the revised Children Neuropsychological and Behavior Scale (CNBS-R2016). The serum level of VA was measured by high-performance liquid chromatography (HPLC).

Results

The serum VA level in children with ASD was significantly lower than that in TD children, especially in boys with ASD. Furthermore, VA levels in male children with ASD were lower than those in female children with ASD. In addition, we found that serum VA level was negatively correlated the SRS, CARS and communication warming behavior of CBNS-R2016 scores in boys with ASD. In terms of developmental quotients, serum VA level was positively associated with the general quotient, language quotient, gross motor quotient and personal-social quotient of boys with ASD, but no difference was found in girls with ASD.

Conclusions

ASD children, especially boys, have lower serum VA levels than TD children. Moreover, serum VA status is more commonly associated with clinical symptoms and neurodevelopment in boys with ASD.

A Longitudinal Cohort Study of Precocious Puberty and Autism Spectrum Disorder

INTRODUCTION

Autism spectrum disorder (ASD) is defined by persistent deficits in communication, socialization, and stereotypic behaviors. It was previously hypothesized that hormone dysfunction is a frequent occurrence among children diagnosed with an ASD.

OBJECTIVES

A hypothesis-testing epidemiological study examined the relationship between precocious puberty (PP) (a known disorder of childhood sex hormone dysfunction) and ASD diagnoses.

METHODS

The Independent Healthcare Research Database is composed of de-identified linked eligibility and claims health-care records prospectively generated from the Florida Medicaid system. A cohort of 101,736 children eligible for Florida Medicaid from 1990 to 2009 and continuously eligible with ≥10 outpatient office visits during the 120-month period following birth were examined using SAS and StatsDirect software. There were 1,593 children (15,738 person-years) in the ASD diagnosed cohort utilizing the Diagnostic and Statistical Manual of Mental Disorders, 4th revision criteria (the International Code for Disease, 9th revision [ICD-9] codes: 299.00 or 299.80) and 100,143 children (996,835 person-years) in the undiagnosed cohort.

RESULTS

The incidence rate of PP (ICD-9 code: 259.1) was examined using Cox proportional hazards ratio (HR) and frequency models. PP per 10,000 person-years in the ASD cohort (43.2) relative to the undiagnosed cohort (13.7) was significantly increased in frequency modeling (risk ratio = 3.15, p < 0.0001) and Cox proportional HR modeling (adjusted HR = 4.64, p < 0.0001). Further analyses revealed the incidence rate of PP diagnosed after 3 years of age was significantly increased (adjusted HR = 5.16, p < 0.0001) in the ASD cohort relative to the undiagnosed cohort but not for the incidence rate of PP diagnosed before 3 years (adjusted HR = 1.57, p = 0.44).

CONCLUSION

This hypothesis-testing study provides strong evidence of an increased incidence rate of PP among children diagnosed with an ASD.

Rethinking autism: the impact of maternal risk factors on autism development

Autism spectrum disorders (ASD) are a group of lifelong neurodevelopmental disorders characterized by cognitive deficits and impaired social and communicative development that have been rising in prevalence in recent decades. These disorders may be accompanied by disabling health issues and often lead to a substantial economic burden. The causes and mechanisms of ASD have not yet been fully elucidated, although it has been reported that genetic background, epigenetic modification, and environmental risk factors all contribute to the development of ASD. Environmental factors, which include prenatal circumstances or events, all play a very important role in the early development of autism, yet the exact mechanism remains largely undetermined. In this review, we promote a 'rethinking' of autism as a neurodevelopmental disease that originates from early life development. We focus on the impact of the prenatal and maternal risk factors such as maternal diabetes, prenatal chemical exposure, and hormone imbalances during pregnancy on the risk for ASD development in children and offspring, identifying important pathological bases and prevention measures for future decades. Further research focused on understanding the role of the environmental factors in the etiology of ASD will drive forward innovation strategies towards intervention and the prevention of the maternal risk factors for autism.

Maternal diabetes-mediated RORA suppression contributes to gastrointestinal symptoms in autism-like mouse offspring

BACKGROUND

Retinoic acid-related orphan receptor alpha (RORA) has been reported to be suppressed in autistic patients and is associated with autism spectrum disorders (ASD), although the potential role and mechanism of RORA on gastrointestinal (GI) symptoms in ASD patients is still not reported. In this study, we aim to investigate the contribution of RORA to GI symptoms through a maternal diabetes-mediated autism-like mouse model.

RESULTS

Male offspring of diabetic dams were treated with either superoxide dismutase (SOD) mimetic MnTBAP or RORA agonist SR1078, or were crossbred with intestine epithelial cells (IEC)-specific RORA knockout (RORA^-/-) mouse. Gene expression, oxidative stress and inflammation were measured in brain tissues, peripheral blood mononuclear cells (PBMC) and IEC, and GI symptoms were evaluated. Our results showed that SOD mimetic MnTBAP completely, while RORA agonist SR1078 partly, reversed maternal diabetes-mediated oxidative stress and inflammation in the brain, PBMC and IEC, as well as GI symptoms, including intestine permeability and altered gut microbiota compositions. IEC-specific RORA deficiency either mimicked or worsened maternal diabetes-mediated GI symptoms as well as oxidative stress and inflammation in IEC, while there was little effect on maternal diabetes-mediated autism-like behaviors.

CONCLUSIONS

We conclude that RORA suppression contributes to maternal diabetes-mediated GI symptoms in autism-like mouse offspring, this study provides a potential therapeutical target for maternal diabetes-mediated GI symptoms in offspring through RORA activation.

Alterations of Prefrontal-Posterior Information Processing Patterns in Autism Spectrum Disorders

Autism spectrum disorder (ASD) is a heterogeneous disorder characterized by different levels of repetitive and stereotypic behavior as well as deficits in social interaction and communication. In this current study, we explored the changes in cerebral neural activities in ASD. The purpose of this study is to investigate whether there exists a dysfunction of interactive information processing between the prefrontal cortex and posterior brain regions in ASD. We investigated the atypical connectivity and information flow between the prefrontal cortex and posterior brain regions in ASD utilizing the entropy connectivity (a kind of directional connectivity) method. Eighty-nine patients with ASD and 94 typical developing (TD) teenagers participated in this study. Two-sample t-tests revealed weakened interactive entropy connectivity between the prefrontal cortex and posterior brain regions. This result indicates that there exists interactive prefrontal-posterior underconnectivity in ASD, and this disorder might lead to less prior knowledge being used and updated. Our proposals highlighted that aforementioned atypical change might accelerate the deoptimization of brain networks in ASD.

Maternal diabetes-mediated RORA suppression in mice contributes to autism-like offspring through inhibition of aromatase

Retinoic acid-related orphan receptor alpha (RORA) suppression is associated with autism spectrum disorder (ASD) development, although the mechanism remains unclear. In this study, we aim to investigate the potential effect and mechanisms of RORA suppression on autism-like behavior (ALB) through maternal diabetes-mediated mouse model. Our in vitro study in human neural progenitor cells shows that transient hyperglycemia induces persistent RORA suppression through oxidative stress-mediated epigenetic modifications and subsequent dissociation of octamer-binding transcription factor 3/4 from the RORA promoter, subsequently suppressing the expression of aromatase and superoxide dismutase 2. The in vivo mouse study shows that prenatal RORA deficiency in neuron-specific RORA null mice mimics maternal diabetes-mediated ALB; postnatal RORA expression in the amygdala ameliorates, while postnatal RORA knockdown mimics, maternal diabetes-mediated ALB in offspring. In addition, RORA mRNA levels in peripheral blood mononuclear cells decrease to 34.2% in ASD patients (n = 121) compared to the typically developing group (n = 118), and the related Receiver Operating Characteristic curve shows good sensitivity and specificity with a calculated 84.1% of Area Under the Curve for ASD diagnosis. We conclude that maternal diabetes contributes to ALB in offspring through suppression of RORA and aromatase, RORA expression in PBMC could be a potential marker for ASD screening.

Hong Yu, Yanbin Niu, Guohua Jia et al. integrate in vitro, in vivo, and human experiments to examine a link between RORA expression on autism-like behavior. Their results suggest that maternal diabetes may contribute to autism-like behavior via RORA suppression.

Autism-Related Transcription Factors Underlying the Sex-Specific Effects of Prenatal Bisphenol A Exposure on Transcriptome-Interactome Profiles in the Offspring Prefrontal Cortex

Bisphenol A (BPA) is an environmental risk factor for autism spectrum disorder (ASD). BPA exposure dysregulates ASD-related genes in the hippocampus and neurological functions of offspring. However, whether prenatal BPA exposure has an impact on genes in the prefrontal cortex, another brain region highly implicated in ASD, and through what mechanisms have not been investigated. Here, we demonstrated that prenatal BPA exposure disrupts the transcriptome-interactome profiles of the prefrontal cortex of neonatal rats. Interestingly, the list of BPA-responsive genes was significantly enriched with known ASD candidate genes, as well as genes that were dysregulated in the postmortem brain tissues of ASD cases from multiple independent studies. Moreover, several differentially expressed genes in the offspring's prefrontal cortex were the targets of ASD-related transcription factors, including AR, ESR1, and RORA. The hypergeometric distribution analysis revealed that BPA may regulate the expression of such genes through these transcription factors in a sex-dependent manner. The molecular docking analysis of BPA and ASD-related transcription factors revealed novel potential targets of BPA, including RORA, SOX5, TCF4, and YY1. Our findings indicated that prenatal BPA exposure disrupts ASD-related genes in the offspring's prefrontal cortex and may increase the risk of ASD through sex-dependent molecular mechanisms, which should be investigated further.

Aromatase in the Human Brain

The aromatase cytochrome P450 (P450arom) enzyme, or estrogen synthase, which is coded by the CYP19A1 gene, is widely expressed in a subpopulation of excitatory and inhibitory neurons, astrocytes, and other cell types in the human brain. Experimental studies in laboratory animals indicate a prominent role of brain aromatization of androgens to estrogens in regulating different brain functions. However, the consequences of aromatase expression in the human brain remain poorly understood. Here, we summarize the current knowledge about aromatase expression in the human brain, abundant in the thalamus, amygdala, hypothalamus, cortex, and hippocampus and discuss its role in the regulation of sensory integration, body homeostasis, social behavior, cognition, language, and integrative functions. Since brain aromatase is affected by neurodegenerative conditions and may participate in sex-specific manifestations of autism spectrum disorders, major depressive disorder, multiple sclerosis, stroke, and Alzheimer's disease, we discuss future avenues for research and potential clinical and therapeutic implications of the expression of aromatase in the human brain.

Hyperandrogenism? Increased 17, 20-Lyase Activity? A Metanalysis and Systematic Review of Altered Androgens in Boys and Girls with Autism

Introduction: There is increasing evidence that steroid hormone levels and, especially, androgen levels are elevated in autism. An overactivity of 17, 20-lyase with a higher production of the testosterone precursors dehydroepiandrosterone (DHEA) and androstenedione/androstenediol seems especially present in autism. Methods: An encompassing literature analysis was performed, searching for altered androgens in children with autism and using preferred reporting items for systematic reviews and meta-analysis (PRISMA) guidelines. Included were all studies published before 31 March 2021 found using the following electronic databases: PubMed, Google Scholar, Cochrane Library, Scopus, and TRIP. Eight studies with boys and three studies with girls where steroid hormone measurements were performed from either plasma, urine, or saliva were found and analyzed. Analyses were performed for DHEA(-S/-C), androstenedione/androstenediol, and testosterone. Effect sizes were calculated for each parameter between mean concentrations for children with autism versus healthy controls. Results: Higher levels of androgens in autism were detected, with the majority of calculated effect sizes being larger than one. Conclusions: We found higher levels of the main testosterone precursors DHEA, androstenedione, and androstenediol, likely causing an additionally higher level of testosterone, and an increased 17, 20-lyase activity is therefore implied. Medications already used in PCOS such as metformin might be considered to treat hyperandrogenism in autism following further research.

The neuropathology of autism: A systematic review of post-mortem studies of autism and related disorders

Post-mortem studies allow for the direct investigation of brain tissue in those with autism and related disorders. Several review articles have focused on aspects of post-mortem abnormalities but none has brought together the entire post-mortem literature. Here, we systematically review the evidence from post-mortem studies of autism, and of related disorders that present with autistic features. The literature consists of a small body of studies with small sample sizes, but several remarkably consistent findings are evident. Cortical layering is largely undisturbed, but there are consistent reductions in minicolumn numbers and aberrant myelination. Transcriptomics repeatedly implicate abberant synaptic, metabolic, proliferation, apoptosis and immune pathways. Sufficient replicated evidence is available to implicate non-coding RNA, aberrant epigenetic profiles, GABAergic, glutamatergic and glial dysfunction in autism pathogenesis. Overall, the cerebellum and frontal cortex are most consistently implicated, sometimes revealing distinct region-specific alterations. The literature on related disorders such as Rett syndrome, Fragile X and copy number variations (CNVs) predisposing to autism is particularly small and inconclusive. Larger studies, matched for gender, developmental stage, co-morbidities and drug treatment are required.

Predicting the Risk Genes of Autism Spectrum Disorders

Autism spectrum disorder (ASD) refers to a wide spectrum of neurodevelopmental disorders that emerge during infancy and continue throughout a lifespan. Although substantial efforts have been made to develop therapeutic approaches, core symptoms persist lifelong in ASD patients. Identifying the brain temporospatial regions where the risk genes are expressed in ASD patients may help to improve the therapeutic strategies. Accordingly, this work aims to predict the risk genes of ASD and identify the temporospatial regions of the brain structures at different developmental time points for exploring the specificity of ASD gene expression in the brain that would help in possible ASD detection in the future. A dataset consisting of 13 developmental stages ranging from 8 weeks post-conception to 8 years from 26 brain structures was retrieved from the BrainSpan atlas. This work proposes a support vector machine–based risk gene prediction method ASD-Risk to distinguish the risk genes of ASD and non-ASD genes. ASD-Risk used an optimal feature selection algorithm called inheritable bi-objective combinatorial genetic algorithm to identify the brain temporospatial regions for prediction of the risk genes of ASD. ASD-Risk achieved a 10-fold cross-validation accuracy, sensitivity, specificity, area under a receiver operating characteristic curve, and a test accuracy of 81.83%, 0.84, 0.79, 0.84, and 72.27%, respectively. We prioritized the temporospatial features according to their contribution to the prediction accuracy. The top identified temporospatial regions of the brain for risk gene prediction included the posteroventral parietal cortex at 13 post-conception weeks feature. The identified temporospatial features would help to explore the risk genes that are specifically expressed in different brain regions of ASD patients.

Atrx Deletion in Neurons Leads to Sexually Dimorphic Dysregulation of miR-137 and Spatial Learning and Memory Deficits

ATRX gene mutations have been identified in syndromic and non-syndromic intellectual disabilities in humans. ATRX is known to maintain genomic stability in neuroprogenitor cells, but its function in differentiated neurons and memory processes remains largely unresolved. Here, we show that the deletion of neuronal Atrx in mice leads to distinct hippocampal structural defects, fewer presynaptic vesicles, and an enlarged postsynaptic area at CA1 apical dendrite-axon junctions. We identify male-specific impairments in long-term contextual memory and in synaptic gene expression, linked to altered miR-137 levels. We show that ATRX directly binds to the miR-137 locus and that the enrichment of the suppressive histone mark H3K27me3 is significantly reduced upon the loss of ATRX. We conclude that the ablation of ATRX in excitatory forebrain neurons leads to sexually dimorphic effects on miR-137 expression and on spatial memory, identifying a potential therapeutic target for neurological defects caused by ATRX dysfunction.

•

Loss of ATRX in neurons has sexually dimorphic effects on long-term spatial memory

•

Targeted deletion of neuronal ATRX in mice causes ultrastructural synaptic defects

•

ATRX null neurons show sex-specific changes in miR-137 and target synaptic transcripts

•

ATRX directly binds and suppresses miR-137 in males via enrichment of H3K27me3

Origin of Sex-Biased Mental Disorders: An Evolutionary Perspective

Sexual dimorphism or sex bias in diseases and mental disorders have two biological causes: sexual selection and sex hormones. We review the role of sexual selection theory and bring together decades of molecular studies on the variation and evolution of sex-biased genes and provide a theoretical basis for the causes of sex bias in disease and health. We present a Sexual Selection-Sex Hormone theory and show that male-driven evolution, including sexual selection, leads to: (1) increased male vulnerability due to negative pleiotropic effects associated with male-driven sexual selection and evolution; (2) increased rates of male-driven mutations and epimutations in response to early fitness gains and at the cost of late fitness; and (3) enhanced female immunity due to antagonistic responses to mutations that are beneficial to males but harmful to females, reducing female vulnerability to diseases and increasing the thresholds for disorders such as autism. Female-driven evolution, such as reproduction-related fluctuation in female sex hormones in association with stress and social condition, has been shown to be associated with increased risk of certain mental disorders such as major depression disorder in women. Bodies have history, cells have memories. An evolutionary framework, such as the Sexual Selection–Sex Hormone theory, provides a historical perspective for understanding how the differences in the sex-biased diseases and mental disorders have evolved over time. It has the potential to direct the development of novel preventive and treatment strategies.

Sex differences in the effects of prenatal bisphenol A exposure on autism-related genes and their relationships with the hippocampus functions

Our recent study has shown that prenatal exposure to bisphenol A (BPA) altered the expression of genes associated with autism spectrum disorder (ASD). In this study, we further investigated the effects of prenatal BPA exposure on ASD-related genes known to regulate neuronal viability, neuritogenesis, and learning/memory, and assessed these functions in the offspring of exposed pregnant rats. We found that prenatal BPA exposure increased neurite length, the number of primary neurites, and the number of neurite branches, but reduced the size of the hippocampal cell body in both sexes of the offspring. However, in utero exposure to BPA decreased the neuronal viability and the neuronal density in the hippocampus and impaired learning/memory only in the male offspring while the females were not affected. Interestingly, the expression of several ASD-related genes (e.g. Mief2, Eif3h, Cux1, and Atp8a1) in the hippocampus were dysregulated and showed a sex-specific correlation with neuronal viability, neuritogenesis, and/or learning/memory. The findings from this study suggest that prenatal BPA exposure disrupts ASD-related genes involved in neuronal viability, neuritogenesis, and learning/memory in a sex-dependent manner, and these genes may play an important role in the risk and the higher prevalence of ASD in males subjected to prenatal BPA exposure.

Are Steroid Hormones Dysregulated in Autistic Girls?

Evidence of altered cholesterol and steroid hormones in autism is increasing. However, as boys are more often affected, evidence mainly relates to autistic males, whereas evidence for affected autistic girls is sparse. Therefore, a comprehensive gas chromatography mass spectrometry-based steroid hormone metabolite analysis was conducted from autistic girls. Results show increased levels of several steroid hormones, especially in the class of androgens in autistic girls such as testosterone or androstenediol. The increase of the majority of steroid hormones in autistic girls is probably best explained multifactorially by a higher substrate provision in line with the previously developed cholesterol hypothesis of autism.

Nutritional and environmental contributions to Autism Spectrum Disorders: Focus on nutrigenomics as complementary therapy

The prevalence of autism spectrum disorders (ASD) has risen sharply in the last 30 years, posing a major public health concern and a big emotional and financial challenge for families. While the underlying causes remain to be fully elucidated, evidence shows moderate genetic heritability contribution, but heavy environmental influence. Over the last decades, modern lifestyle has deeply changed our eating, rest, and exercise habits, while exposure to air, water, and food chemical pollution has increased due to indiscriminate use of pesticides, food additives, adjuvants, and antibiotics. The result is a drastic change in the quality of our energy source input, and an overload for antioxidant and detoxification pathways that compromises normal metabolism and homeostasis. Current research shows high prevalence of food selectivity and/or food allergy among children with autism, resulting in essential micronutrient deficits that may trigger or aggravate physical and cognitive symptoms. Nutrigenomics is an emerging discipline that focuses on genotype-micronutrient interaction, and a useful approach to tailor low risk, personalized interventions through diet and micronutrient supplementation. Here, we review available literature addressing the role of micronutrients in the symptomatology of ASD, the metabolic pathways involved, and their therapeutic relevance. Personalized and supervised supplementation according to individual needs is suggested as a complement of traditional therapies to improve outcome both for children with autism and their families.

MiR-18a-downregulated RORA inhibits the proliferation and tumorigenesis of glioma using the TNF-α-mediated NF-κB signaling pathway

BACKGROUND

Glioma has a poor prognosis, and is the most common primary and lethal primary malignant tumor in the central nervous system. Retinoic acid receptor-related orphan receptor A (RORA) is a member of the ROR subfamily of orphan receptors and plays an anti-tumor role in several cancers.

METHODS

A cell viability assay, the Edu assay, neurosphere formation assay, and xenograft experiments were used to detect the proliferative abilities of glioma cell line, glioma stem cells (GSCs). Western blotting, ELISAs, and luciferase reporter assays were used to detect the presence of possible microRNAs.

FINDINGS

Our study found for the first time that RORA was expressed at low levels in gliomas, and was associated with a good prognosis. RORA overexpression inhibited the proliferation and tumorigenesis of glioma cell lines and GSCs via inhibiting the TNF-α mediated NF-κB signaling pathway. In addition, microRNA-18a had a promoting effect on gliomas, and was the possible reason for low RORA expression in gliomas.

INTERPRETATION

RORA may be a promising therapeutic target in the treatment of gliomas.

Identification of gender-related metabolic disturbances in autism spectrum disorders using urinary metabolomics

Autism spectrum disorders (ASD) are a highly heterogeneous group of neurodevelopmental disorders that are more commonly diagnosed in boys than in girls. The reasons for gender differences in ASD are unknown and no definitive current evidence can explain male predominance. Therefore, in search for laboratory biomarkers responsible for ASD, a comprehensive metabolomics study was performed by metabolic profiling of urine samples in 51 ASD subjects and 51 age- and sex-matched children with typical development. Orthogonal partial least-squares discriminant analysis (OPLS-DA) models with poor quality failed to perform the analysis based on gender in the ASD and control groups. OPLS-DA models based on single-sex samples, especially in female subjects, had better clustering between the ASD and control groups with an increase in the R² and Q² values compared with those in the whole group. Significantly increased levels of adenine, 2-Methylguanosine, creatinine, and 7alpha-hydroxytestololactone and a decrease in creatine were observed in the female ASD subjects. In particular, 7alpha-hydroxytestololactone, which has a structure similar to that of testolactone, was positively correlated with adenine (Pearson correlation coefficient, r = 0.738, p < 0.01), creatinine (r = 0.826, p < 0.01), and 2-Methylguanosine (r = 0.757, p < 0.01) and negatively correlated with creatine (r=-0.413, p < 0.05). A receiver operating characteristic curve analysis using the creatinine:creatine ratio yielded an area under the curve of 0.913 (95% CI: 0.806-1). These metabolites may be sex-related or sex-sensitive to an extent and can be valuable for identification of the molecular pathways involved in the gender bias in manifestation of ASD. The creatinine:creatine ratio has a potential to be a good predictor of ASD in the female subjects.

Genetic Causes and Modifiers of Autism Spectrum Disorder

Autism Spectrum Disorder (ASD) is one of the most prevalent neurodevelopmental disorders, affecting an estimated 1 in 59 children. ASD is highly genetically heterogeneous and may be caused by both inheritable and de novo gene variations. In the past decade, hundreds of genes have been identified that contribute to the serious deficits in communication, social cognition, and behavior that patients often experience. However, these only account for 10-20% of ASD cases, and patients with similar pathogenic variants may be diagnosed on very different levels of the spectrum. In this review, we will describe the genetic landscape of ASD and discuss how genetic modifiers such as copy number variation, single nucleotide polymorphisms, and epigenetic alterations likely play a key role in modulating the phenotypic spectrum of ASD patients. We also consider how genetic modifiers can alter convergent signaling pathways and lead to impaired neural circuitry formation. Lastly, we review sex-linked modifiers and clinical implications. Further understanding of these mechanisms is crucial for both comprehending ASD and for developing novel therapies.

A Bayesian framework that integrates multi-omics data and gene networks predicts risk genes from schizophrenia GWAS data

Genome-wide association studies (GWAS) have identified >100 schizophrenia (SCZ)-associated loci, but using these findings to illuminate disease biology remains a challenge. Here, we present integrative RIsk Gene Selector (iRIGS), a Bayesian framework that integrates multi-omics data and gene networks to infer risk genes in GWAS loci. By applying iRIGS to SCZ GWAS data, we predicted a set of high-confidence risk genes (HRGs), most of which are not the nearest genes to the GWAS index variants. HRGs account for a significantly enriched heritability estimated by stratified LD-score regression. Moreover, HRGs are predominantly expressed in brain tissues, especially prenatally, and are enriched for targets of approved drugs, suggesting opportunities to reposition existing drugs for SCZ. Thus, iRIGS can leverage accumulating functional genomics and GWAS data to advance understanding of SCZ etiology and potential therapeutics.

Variations in Genes Related to Sleep Patterns in Children With Autism Spectrum Disorder

Background:

Sleep disturbance is a frequent comorbidity in children with autism spectrum disorder (ASD), affecting an estimated 40–80% of cases. Previous reports have shown relationships between several circadian rhythm–related genes and sleep problems in ASD. The purpose of the present study was to relate variation in and around melatonin synthesis and suprachiasmatic nucleus genes to sleep problems in a large sample of children with ASD.

Method:

This secondary analysis used existing genotypic and phenotypic data for 2,065 children, aged 4–18 years, from the Simons Simplex Collection (SSC). Sleep problems were measured with the SSC Sleep Interview. Expression quantitative trait loci and single nucleotide polymorphisms in 25 circadian genes were chosen primarily for their impact on expression levels of target genes in the brain. Associations between variants and composite sleep problems, nighttime problems, daytime problems, and sleep duration problems were calculated using logistic regression analysis. Age, sex, nonverbal IQ, ASD severity, gastrointestinal distress, seizures, and ancestry were included as covariates. Transmission disequilibrium tests were performed to test for overtransmission of alleles in the same variants.

Results:

No significant associations or transmission disequilibrium were found between gene variants and sleep problems in this sample of children with ASD.

Conclusion:

Variation in expression of investigated genes in the melatonin synthesis and suprachiasmatic nucleus pathways did not have notable impacts on sleep problems in this large sample of children with ASD. Future research could explore translational and posttranslational effects of these genes or the effects of genes in other sleep-homeostasis pathways on sleep patterns.

Phenotypic subgrouping and multi-omics analyses reveal reduced diazepam-binding inhibitor (DBI) protein levels in autism spectrum disorder with severe language impairment

BACKGROUND

The mechanisms underlying autism spectrum disorder (ASD) remain unclear, and clinical biomarkers are not yet available for ASD. Differences in dysregulated proteins in ASD have shown little reproducibility, which is partly due to ASD heterogeneity. Recent studies have demonstrated that subgrouping ASD cases based on clinical phenotypes is useful for identifying candidate genes that are dysregulated in ASD subgroups. However, this strategy has not been employed in proteome profiling analyses to identify ASD biomarker proteins for specific subgroups.

METHODS

We therefore conducted a cluster analysis of the Autism Diagnostic Interview-Revised (ADI-R) scores from 85 individuals with ASD to predict subgroups and subsequently identified dysregulated genes by reanalyzing the transcriptome profiles of individuals with ASD and unaffected individuals. Proteome profiling of lymphoblastoid cell lines from these individuals was performed via 2D-gel electrophoresis, and then mass spectrometry. Disrupted proteins were identified and compared to the dysregulated transcripts and reported dysregulated proteins from previous proteome studies. Biological functions were predicted using the Ingenuity Pathway Analysis (IPA) program. Selected proteins were also analyzed by Western blotting.

RESULTS

The cluster analysis of ADI-R data revealed four ASD subgroups, including ASD with severe language impairment, and transcriptome profiling identified dysregulated genes in each subgroup. Screening via proteome analysis revealed 82 altered proteins in the ASD subgroup with severe language impairment. Eighteen of these proteins were further identified by nano-LC-MS/MS. Among these proteins, fourteen were predicted by IPA to be associated with neurological functions and inflammation. Among these proteins, diazepam-binding inhibitor (DBI) protein was confirmed by Western blot analysis to be expressed at significantly decreased levels in the ASD subgroup with severe language impairment, and the DBI expression levels were correlated with the scores of several ADI-R items.

CONCLUSIONS

By subgrouping individuals with ASD based on clinical phenotypes, and then performing an integrated transcriptome-proteome analysis, we identified DBI as a novel candidate protein for ASD with severe language impairment. The mechanisms of this protein and its potential use as an ASD biomarker warrant further study.

Sex-specific Behavioral Features of Rodent Models of Autism Spectrum Disorder

Sex is an important factor in understanding the clinical presentation, management, and developmental trajectory of children with neuropsychiatric disorders. While much is known about the clinical and neurobehavioral profiles of males with neuropsychiatric disorders, surprisingly little is known about females in this respect. Animal models may provide detailed mechanistic information about sex differences in autism spectrum disorder (ASD) in terms of manifestation, disease progression, and development of therapeutic options. This review aims to widen our understanding of the role of sex in autism spectrum disorder, by summarizing and comparing behavioral characteristics of animal models. Our current understanding of how differences emerge in boys and girls with neuropsychiatric disorders is limited: Information derived from animal studies will stimulate future research on the role of biological maturation rates, sex hormones, sex-selective protective (or aggravating) factors and psychosocial factors, which are essential to devise sex precision medicine and to improve diagnostic accuracy. Moreover, there is a strong need of novel strategies to elucidate the major mechanisms leading to sex-specific autism features, as well as novel models or methods to examine these sex differences.

Investigation of epigenetic regulatory networks associated with autism spectrum disorder (ASD) by integrated global LINE-1 methylation and gene expression profiling analyses

BACKGROUND

The exact cause and mechanisms underlying the pathobiology of autism spectrum disorder (ASD) remain unclear. Dysregulation of long interspersed element-1 (LINE-1) has been reported in the brains of ASD-like mutant mice and ASD brain tissues. However, the role and methylation of LINE-1 in individuals with ASD remain unclear. In this study, we aimed to investigate whether LINE-1 insertion is associated with differentially expressed genes (DEGs) and to assess LINE-1 methylation in ASD.

METHODS

To identify DEGs associated with LINE-1 in ASD, we reanalyzed previously published transcriptome profiles and overlapped them with the list of LINE-1-containing genes from the TranspoGene database. An Ingenuity Pathway Analysis (IPA) of DEGs associated with LINE-1 insertion was conducted. DNA methylation of LINE-1 was assessed via combined bisulfite restriction analysis (COBRA) of lymphoblastoid cell lines from ASD individuals and unaffected individuals, and the methylation levels were correlated with the expression levels of LINE-1 and two LINE-1-inserted DEGs, C1orf27 and ARMC8.

RESULTS

We found that LINE-1 insertion was significantly associated with DEGs in ASD. The IPA showed that LINE-1-inserted DEGs were associated with ASD-related mechanisms, including sex hormone receptor signaling and axon guidance signaling. Moreover, we observed that the LINE-1 methylation level was significantly reduced in lymphoblastoid cell lines from ASD individuals with severe language impairment and was inversely correlated with the transcript level. The methylation level of LINE-1 was also correlated with the expression of the LINE-1-inserted DEG C1orf27 but not ARMC8.

CONCLUSIONS

In ASD individuals with severe language impairment, LINE-1 methylation was reduced and correlated with the expression levels of LINE-1 and the LINE-1-inserted DEG C1orf27. Our findings highlight the association of LINE-1 with DEGs in ASD blood samples and warrant further investigation. The molecular mechanisms of LINE-1 and the effects of its methylation in ASD pathobiology deserve further study.

Are endocrine disrupting compounds environmental risk factors for autism spectrum disorder?

Recent research on the etiology of autism spectrum disorder (ASD) has shifted in part from a singular focus on genetic causes to the involvement of environmental factors and their gene interactions. This shift in focus is a result of the rapidly increasing prevalence of ASD coupled with the incomplete penetrance of this disorder in monozygotic twins. One such area of environmentally focused research is the association of exposures to endocrine disrupting compounds (EDCs) with elevated risk for ASD. EDCs are exogenous chemicals that can alter endogenous hormone activity and homeostasis, thus potentially disrupting the action of sex and other natural hormones at all stages of human development. Inasmuch as sex hormones play a fundamental role in brain development and sexual differentiation, exposure to EDCs in utero during critical stages of development can have lasting neurological and other physiological influences on the developing fetus and, ultimately, the child as well as adult. This review will focus on the possible contributions of EDCs to autism risk and pathogenesis by first discussing the influence of endogenous sex hormones on the autistic phenotype, followed by a review of documented human exposures to EDCs and associations with behaviors relevant to ASD. Mechanistic links between EDC exposures and aberrant neurodevelopment and behaviors are then considered, with emphasis on EDC-induced transcriptional profiles derived from animal and cellular studies. Finally, this review will discuss possible mechanisms through which EDC exposure can lead to persistent changes in gene expression and phenotype, which may in turn contribute to transgenerational inheritance of ASD.

Integrated genome-wide Alu methylation and transcriptome profiling analyses reveal novel epigenetic regulatory networks associated with autism spectrum disorder

Background

Alu elements are a group of repetitive elements that can influence gene expression through CpG residues and transcription factor binding. Altered gene expression and methylation profiles have been reported in various tissues and cell lines from individuals with autism spectrum disorder (ASD). However, the role of Alu elements in ASD remains unclear. We thus investigated whether Alu elements are associated with altered gene expression profiles in ASD.

Methods

We obtained five blood-based gene expression profiles from the Gene Expression Omnibus database and human Alu-inserted gene lists from the TranspoGene database. Differentially expressed genes (DEGs) in ASD were identified from each study and overlapped with the human Alu-inserted genes. The biological functions and networks of Alu-inserted DEGs were then predicted by Ingenuity Pathway Analysis (IPA). A combined bisulfite restriction analysis of lymphoblastoid cell lines (LCLs) derived from 36 ASD and 20 sex- and age-matched unaffected individuals was performed to assess the global DNA methylation levels within Alu elements, and the Alu expression levels were determined by quantitative RT-PCR.

Results

In ASD blood or blood-derived cells, 320 Alu-inserted genes were reproducibly differentially expressed. Biological function and pathway analysis showed that these genes were significantly associated with neurodevelopmental disorders and neurological functions involved in ASD etiology. Interestingly, estrogen receptor and androgen signaling pathways implicated in the sex bias of ASD, as well as IL-6 signaling and neuroinflammation signaling pathways, were also highlighted. Alu methylation was not significantly different between the ASD and sex- and age-matched control groups. However, significantly altered Alu methylation patterns were observed in ASD cases sub-grouped based on Autism Diagnostic Interview-Revised scores compared with matched controls. Quantitative RT-PCR analysis of Alu expression also showed significant differences between ASD subgroups. Interestingly, Alu expression was correlated with methylation status in one phenotypic ASD subgroup.

Conclusion

Alu methylation and expression were altered in LCLs from ASD subgroups. Our findings highlight the association of Alu elements with gene dysregulation in ASD blood samples and warrant further investigation. Moreover, the classification of ASD individuals into subgroups based on phenotypes may be beneficial and could provide insights into the still unknown etiology and the underlying mechanisms of ASD.

Electronic supplementary material

The online version of this article (10.1186/s13229-018-0213-9) contains supplementary material, which is available to authorized users.

Sex Differences in Autism Spectrum Disorder: a Review

PURPOSE OF REVIEW

Neurodevelopmental disorders disproportionately affect males. The mechanisms underlying male vulnerability or female protection are not known and remain understudied. Determining the processes involved is crucial to understanding the etiology and advancing treatment of neurodevelopmental disorders. Here, we review current findings and theories that contribute to male preponderance of neurodevelopmental disorders, with a focus on autism.

RECENT FINDINGS

Recent work on the biological basis of the male preponderance of autism and other neurodevelopmental disorders includes discussion of a higher genetic burden in females and sex-specific gene mutations or epigenetic changes that differentially confer risk to males or protection to females. Other mechanisms discussed are sex chromosome and sex hormone involvement. Specifically, fetal testosterone is involved in many aspects of development and may interact with neurotransmitter, neuropeptide, or immune pathways to contribute to male vulnerability. Finally, the possibilities of female underdiagnosis and a multi-hit hypothesis are discussed. This review highlights current theories of male bias in developmental disorders. Topics include environmental, genetic, and epigenetic mechanisms; theories of sex chromosomes, hormones, neuroendocrine, and immune function; underdiagnosis of females; and a multi-hit hypothesis.

Developmental neurogenetics and multimodal neuroimaging of sex differences in autism

Examining sex differences in the brain has been historically contentious but is nonetheless important for advancing mental health for both girls and boys. Unfortunately, females in biomedical research remain underrepresented in most mental health conditions including autism spectrum disorders (ASD), even though equal inclusion of females would improve treatment for girls and yield benefits to boys. This review examines sex differences in the relationship between neuroanatomy and neurogenetics of ASD. Recent findings reveal that girls diagnosed with ASD exhibit more intellectual and behavioral problems compared to their male counterparts, suggesting that girls may be less likely diagnosed in the absence of such problems or that they require a higher mutational load to meet the diagnostic criteria. Thus far, the female biased effect of chromosome 4, 5p15.33, 8p, 9p24.1, 11p12-13, 15q, and Xp22.3 and the male biased effect of 1p31.3, 5q12.3, 7q, 9q33.3, 11q13.4, 13q33.3, 16p11.2, 17q11-21, Xp22.33/Yp11.31, DRD1, NLGN3, MAOA, and SHANK1 deletion have been discovered in ASD. The SNPs of genes such as RYR2, UPP2, and the androgen receptor gene have been shown to have sex-biasing factors in both girls and boys diagnosed with ASD. These sex-related genetic factors may drive sex differences in the neuroanatomy of these girls and boys, including abnormal enlargement in temporal gray and white matter volumes, and atypical reduction in cerebellar gray matter volumes and corpus callosum fibers projecting to the anterior frontal cortex in ASD girls relative to boys. Such factors may also be responsible for the attenuation of brain sexual differentiation in adult men and women with ASD; however, much remains to be uncovered or replicated. Future research should leverage further the association between neuroanatomy and genetics in girls for an integrated and interdisciplinary understanding of ASD.