Prenatal 1-Nitropyrene Exposure Causes Autism-Like Behavior Partially by Altering DNA Hydroxymethylation in Developing Brain.

Autism spectrum disorder (ASD) is a neurodevelopmental disorder, characterized by social communication disability and stereotypic behavior. This study aims to investigate the impact of prenatal exposure to 1-nitropyrene (1-NP), a key component of motor vehicle exhaust, on autism-like behaviors in a mouse model. Three-chamber test finds that prenatal 1-NP exposure causes autism-like behaviors during the weaning period. Patch clamp shows that inhibitory synaptic transmission is reduced in medial prefrontal cortex of 1-NP-exposed weaning pups. Immunofluorescence finds that prenatal 1-NP exposure reduces the number of prefrontal glutamate decarboxylase 67 (GAD67) positive interneurons in fetuses and weaning pups. Moreover, prenatal 1-NP exposure retards tangential migration of GAD67-positive interneurons and downregulates interneuron migration-related genes, such as Nrg1, Erbb4, and Sema3F, in fetal forebrain. Mechanistically, prenatal 1-NP exposure reduces hydroxymethylation of interneuron migration-related genes through inhibiting ten-eleven translocation (TET) activity in fetal forebrain. Supplement with alpha-ketoglutarate (α-KG), a cofactor of TET enzyme, reverses 1-NP-induced hypohydroxymethylation at specific sites of interneuron migration-related genes. Moreover, α-KG supplement alleviates 1-NP-induced migration retardation of interneurons in fetal forebrain. Finally, maternal α-KG supplement improves 1-NP-induced autism-like behaviors in weaning offspring. In conclusion, prenatal 1-NP exposure causes autism-like behavior partially by altering DNA hydroxymethylation of interneuron migration-related genes in developing brain.

Chronic exposure of female mice to selective serotonin reuptake inhibitors during lactation induces vocal behavior deficits in pre-weaned offspring.

Developmental factors for autism spectrum disorders (ASDs) have been an ongoing debate despite an increasing number of reports on genetic factors. Recent studies have suggested maternal intake of selective serotonin reuptake inhibitors (SSRIs) as a possible developmental factor elevating the risk for ASD in offspring. Here, we show that maternal exposure of mice to an SSRI, Fluoxetine (FLX), induces abnormal ultrasonic vocalizations (USVs), an indicator of ASD-related behavior. We tested the effect of FLX intake during pregnancy, lactation, or both. We found that the lactation and both conditions decreased the number of USVs emitted by offspring pups. An index for assessing the syllables' frequency modulation revealed that highly modulated syllables appeared to be inhibited only in both conditions. Furthermore, we found that the number of serotonergic neurons at adulthood was reduced in the progeny of mice treated with FLX in all conditions. In addition, maternal exposure to FLX through pregnancy and lactation induced a high death rate of early post-natal pups. These suggest that the maternal exposure to SSRIs affects early development of offsprings as well as the serotonergic system. Focusing on vocal communication, our results indicate that intake of an SSRI during lactation increases the risk of abnormal USVs in pups, and provides potential insights into the development of ASD.

Poly(I:C)-induced maternal immune activation causes elevated self-grooming in male rat offspring: Involvement of abnormal postpartum static nursing in dam.

Introduction: Maternal immune activation (MIA) is closely related to the onset of autism-like behaviors in offspring, but the mechanism remains unclear. Maternal behaviors can influence offspring's development and behaviors, as indicated in both human and animal studies. We hypothesized that abnormal maternal behaviors in MIA dams might be other factors leading to delayed development and abnormal behaviors in offspring. Methods: To verify our hypothesis, we analyzed poly(I:C)-induced MIA dam's postpartum maternal behavior and serum levels of several hormones related to maternal behavior. Pup's developmental milestones and early social communication were recorded and evaluated in infancy. Other behavioral tests, including three-chamber test, self-grooming test, open field test, novel object recognition test, rotarod test and maximum grip test, were performed in adolescence of pups. Results: Our results showed that MIA dams exhibit abnormal static nursing behavior but normal basic care and dynamic nursing behavior. The serum levels of testosterone and arginine vasopressin in MIA dams were significantly reduced compared with control dams. The developmental milestones, including pinna detachment, incisor eruption and eye opening, were significantly delayed in MIA offspring compared with control offspring, while the weight and early social communication showed no significant differences between the two groups. Behavioral tests performed in adolescence showed that only male MIA offspring display elevated self-grooming behaviors and reduced maximum grip. Discussion: In conclusion, MIA dams display abnormal postpartum static nursing behavior concomitantly with reduced serum levels of testosterone and arginine vasopressin, possibly involving in the pathogenesis of delayed development and elevated self-grooming in male offspring. These findings hint that improving dam's postpartum maternal behavior might be a potential regime to counteract delayed development and elevated self-grooming in male MIA offspring.

Food Allergy-Induced Autism-Like Behavior is Associated with Gut Microbiota and Brain mTOR Signaling.

Purpose: Food allergy-induced autism-like behavior has been increasing for decades, but the causal drivers of this association are unclear. We sought to test the association of gut microbiota and mammalian/mechanistic target of rapamycin (mTOR) signaling with cow's milk allergy (CMA)-induced autism pathogenesis. Methods: Mice were sensitized intragastrically with whey protein containing cholera toxin before sensitization on intraperitoneal injection with whey-containing alum, followed by intragastric allergen challenge to induce experimental CMA. The food allergic immune responses, ASD-like behavioral tests and changes in the mTOR signaling pathway and gut microbial community structure were performed. Results: CMA mice showed autism-like behavioral abnormalities and several distinct biomarkers. These include increased levels of 5-hydroxymethylcytosine (5-hmC) in the hypothalamus; c-Fos were predominantly located in the region of the lateral orbital prefrontal cortex (PFC), but not ventral; decreased serotonin 1A in amygdala and PFC. CMA mice exhibited a specific microbiota signature characterized by coordinate changes in the abundance of taxa of several bacterial genera, including the Lactobacillus. Interestingly, the changes were accompanied by promoted mTOR signaling in the brain of CMA mice. Conclusion: We found that disease-associated microbiota and mTOR activation may thus play a pathogenic role in the intestinal, immunological, and psychiatric Autism Spectrum Disorder (ASD)-like symptoms seen in CAM associated autism. However, this is only a preliminary study, and their mechanisms require further investigation.

MACF1, Involved in the 1p34.2p34.3 Microdeletion Syndrome, is Essential in Cortical Progenitor Polarity and Brain Integrity.

1p34.2p34.3 deletion syndrome is characterized by an increased risk for autism. Microtubule Actin Crosslinking Factor 1 (MACF1) is one candidate gene for this syndrome. It is unclear, however, how MACF1 deletion is linked to brain development and neurodevelopmental deficits. Here we report on Macf1 deletion in the developing mouse cerebral cortex, focusing on radial glia polarity and morphological integrity, as these are critical factors in brain formation. We found that deleting Macf1 during cortical development resulted in double cortex/subcortical band heterotopia as well as disrupted cortical lamination. Macf1-deleted radial progenitors showed increased proliferation rates compared to control cells but failed to remain confined within their defined proliferation zone in the developing brain. The overproliferation of Macf1-deleted radial progenitors was associated with elevated cell cycle speed and re-entry. Microtubule stability and actin polymerization along the apical ventricular area were decreased in the Macf1 mutant cortex. Correspondingly, there was a disconnection between radial glial fibers and the apical and pial surfaces. Finally, we observed that Macf1-mutant mice exhibited social deficits and aberrant emotional behaviors. Together, these results suggest that MACF1 plays a critical role in cortical progenitor proliferation and localization by promoting glial fiber stabilization and polarization. Our findings may provide insights into the pathogenic mechanism underlying the 1p34.2p34.3 deletion syndrome.

A preliminary study on abnormal brain function and autistic behavior in mice caused by dcf1 deletion.

Autism is one of the urgent problems in neuroscience. Early research in our laboratory found that dcf1 gene-deficient mice exhibited autistic behavior. Reviewing the literature, we know that the caudate putamen (CPu) brain region is closely related to the occurrence of autism. In this study, we observed that the electrical signal in the abnormal brain region of adult mice was enhanced by using field potential detection for the corresponding brain region. We then used retrovirus markers to track neurons in the CPu brain region and found that there are neural projections in the hippocampus-CPu brain region. Therefore, we selected DREADDs (Designer receptors exclusively activated by designer drugs) to inhibit the abnormal brain region of the mouse and found, through behavioral testing, that this can inhibit the autistic behavior of mice. This research provides new evidence for the understanding of the cause of autism and has accumulated new basis for the treatment of autism. It has theoretical significance and potential application value for the understanding and treatment of autism.

Perinatal Exposure to Diesel Exhaust-Origin Secondary Organic Aerosol Induces Autism-Like Behavior in Rats.

Autism spectrum disorder (ASD) is a neurodevelopmental disorder characterized by impaired social communication, poor social interactions, and repetitive behaviors. We aimed to examine autism-like behaviors and related gene expressions in rats exposed to diesel exhaust (DE)-origin secondary organic aerosol (DE-SOA) perinatally. Sprague-Dawley pregnant rats were exposed to clean air (control), DE, and DE-SOA in the exposure chamber from gestational day 14 to postnatal day 21. Behavioral phenotypes of ASD were investigated in 10~13-week-old offspring using a three-chambered social behavior test, social dominance tube test, and marble burying test. Prefrontal cortex was collected to examine molecular analyses including neurological and immunological markers and glutamate concentration, using RT-PCR and ELISA methods. DE-SOA-exposed male and female rats showed poor sociability and social novelty preference, socially dominant behavior, and increased repetitive behavior. Serotonin receptor (5-HT(5B)) and brain-derived neurotrophic factor (BDNF) mRNAs were downregulated whereas interleukin 1 ß (IL-ß) and heme oxygenase 1 (HO-1) mRNAs were upregulated in the prefrontal cortex of male and female rats exposed to DE-SOA. Glutamate concentration was also increased significantly in DE-SOA-exposed male and female rats. Our results indicate that perinatal exposure to DE-SOA may induce autism-like behavior by modulating molecules such as neurological and immunological markers in rats.

Postnatal AVP treatments prevent social deficit in adolescence of valproic acid-induced rat autism model.

Studies have shown that arginine-vasopressin (AVP) is an important neuropeptide regulating social behaviors. The present work aimed to detect changes in the AVP numbers and level in a valproic acid (VPA)-induced rat model of autism and the underlying mechanism of its pathogenesis. Our results indicated that infants exposed to VPA showed obviously impaired communication and repetitive behaviors with reduced number of AVP-ir cells in paraventricular nucleus (PVN) and cerebrospinal fluid (CSF). The postnatal subcutaneous injection of AVP can alleviate social preference deficits and stereotyped behaviors, accompanied with the increase of the AVP concentrations in the CSF. We concluded that AVP system was involved in etiology of VPA-induced autism-like symptoms and postnatal AVP treatment rescued the behavioral deficits,which could be a promising treatment for autism.

Autism-like behaviors and abnormality of glucose metabolism in offspring derived from aging males with epigenetically modified sperm.

Accumulating evidence from epidemiological studies of humans and genetic models in rodents has shown that offspring from males of advanced paternal age (APA) are susceptible to metabolic and neurological disorders. However, knowledge of molecular mechanism(s) underlying these metabolic and behavioral changes at the intergeneration and trans-generation levels from APA is limited. Here, we characterized changes on glucose and cholesterol metabolism, and also autism spectrum disorders (ASD)-like behaviors in 1st and 2nd generations from 12- and 18-month-old male mice, respectively. Whole Genome Bisulfite Sequencing (WGBS) of sperm from APA mice identified differentially methylated regions (DMRs) within the whole genome, and DMRs within promoter regions, suggesting that specific genes and relevant pathways might be associated with autism and aberrant glucose metabolism in the offspring from APA males. These results strongly suggest that epigenetic reprogramming induced by aging in male sperm may lead to high risks of aberrant glucose metabolism and the development of ASD behaviors in intergenerational and transgenerational offspring.

Berberine Ameliorates Prenatal Dihydrotestosterone Exposure-Induced Autism-Like Behavior by Suppression of Androgen Receptor.

Many epidemiology studies have shown that maternal polycystic ovary syndrome (PCOS) results in a greater risk of autism spectrum disorders (ASD) development, although the detailed mechanism remains unclear. In this study, we aimed to investigate the potential mechanism and provide a possible treatment for PCOS-mediated ASD through three experiments: Experiment 1: real-time PCR and western blots were employed to measure gene expression in human neurons, and the luciferase reporter assay and chromatin immunoprecipitation (ChIP) was used to map the responsive elements on related gene promoters. Experiment 2: pregnant dams were prenatally exposed to dihydrotestosterone (DHT), androgen receptor (AR) knockdown (shAR) in the amygdala, or berberine (BBR), and the subsequent male offspring were used for autism-like behavior (ALB) assay followed by biomedical analysis, including gene expression, oxidative stress, and mitochondrial function. Experiment 3: the male offspring from prenatal DHT exposed dams were postnatally treated by either shAR or BBR, and the offspring were used for ALB assay followed by biomedical analysis. Our findings showed that DHT treatment suppresses the expression of estrogen receptor ß (ERß) and superoxide dismutase 2 (SOD2) through AR-mediated hypermethylation on the ERß promoter, and BBR treatment suppresses AR expression through hypermethylation on the AR promoter. Prenatal DHT treatment induces ERß suppression, oxidative stress and mitochondria dysfunction in the amygdala with subsequent ALB behavior in male offspring, and AR knockdown partly diminishes this effect. Furthermore, both prenatal and postnatal treatment of BBR partly restores prenatal DHT exposure-mediated ALB. In conclusion, DHT suppresses ERß expression through the AR signaling pathway by hypermethylation on the ERß promoter, and BBR restores this effect through AR suppression. Prenatal DHT exposure induces ALB in offspring through AR-mediated ERß suppression, and both prenatal and postnatal treatment of BBR ameliorates this effect. We conclude that BBR ameliorates prenatal DHT exposure-induced ALB through AR suppression, this study may help elucidate the potential mechanism and identify a potential treatment through using BBR for PCOS-mediated ASD.

Gestational B-vitamin supplementation alleviates PM2.5-induced autism-like behavior and hippocampal neurodevelopmental impairment in mice offspring.

Gestational exposure to PM2.5 is a worldwide environmental issue associated with long-lasting behavior abnormalities and neurodevelopmental impairments in the hippocampus of offspring. PM2.5 may induce hippocampus injury and lead to autism-like behavior such as social communication deficits and stereotyped repetitive behavior in children through neuroinflammation and neurodegeneration. Here, we investigated the preventive effect of B-vitamin on PM2.5-induced deleterious effects by focusing on anti-inflammation, antioxidant, synaptic remodeling and neurodevelopment. Pregnant mice were randomly divided into three groups including control group (mice subject to PBS only), model group (mice subject to both 30 µL PM2.5 of 3.456 µg/µL and 10 mL/(kg·d) PBS), and intervention group (mice subject to both 30 µL PM2.5 of 3.456 µg/µL and 10 mL/(kg·d) B-vitamin supplementation (folic acid, vitamin B6 and vitamin B12 with concentrations at 0.06, 1.14 and 0.02 mg/mL, respectively)). In the current study B-vitamin significantly alleviated neurobehavioral impairment reflected in reduced social communication disorders, stereotyped repetitive behavior, along with learning and spatial memory impairment in PM2.5-stimulated mice offspring. Next, B-vitamin corrected synaptic loss and reduced mitochondrial damage in hippocampus of mice offspring, demonstrated by normalized synapse quantity, synaptic cleft, postsynaptic density (PSD) thickness and length of synaptic active area. Furthermore, significantly down-regulated expression of pro-inflammatory cytokines including NF-κB, TNF-α and IL-1ß, and lipid peroxidation were found. We observed elevated levels of oxidant-related genes (SOD, GSH and GSH-Px). Moreover, decreased cleaved caspase-3 and TUNEL-positive cells suggested inhibited PM2.5-induced apoptosis by B-vitamin. Furthermore, B-vitamin increased neurogenesis by increasing EdU-positive cells in the subgranular zone (SGZ) of offspring. Collectively, our results suggest that B-vitamin supplementation exerts preventive effect on autism-like behavior and neurodevelopmental impairment in hippocampus of mice offspring gestationally exposed to PM2.5, to which alleviated mitochondrial damage, increased anti-inflammatory and antioxidant capacity and synaptic efficiency, reduced neuronal apoptosis and improved hippocampal neurogenesis may contribute.

[Association between pregnancy-related anxiety of pregnant women and autism-like behavior in their offspring at 18 months of age].

Objective: To investigate the relationship of pregnancy-related anxiety of pregnant women in second/third trimesters and autism-like behaviors in their offspring at 18 months of age. Methods: Based on a prospective cohort study design, we evaluated the situation of pregnancy-related anxiety of women during second and third trimesters through a Pregnancy-Related Anxiety Questionnaire. Subjects under study were classified into three groups, 1) those with pregnancy- related anxiety during both trimesters, 2) those with pregnancy-related anxiety at one trimester and 3) those without pregnancy-related anxiety in either trimester. When their children were 18 months, autism-like behaviors (ALB) were evaluated, using the part A of Checklist for Autism in Toddlers-23, and then classified into three groups as non-ALB group, minor ALB group and major ALB group. Multi-nominal logistic Regression was used to analyze the relationship of pregnancy-related anxiety with autism-like behaviors. Results: Compared with non-ALB group, children whose mother with pregnancy-related anxiety during both trimesters presented significant higher risk on ALB than children whose mother without pregnancy-related anxiety in these two periods (relative risk, RR=2.43, 95% CI: 1.21-4.86, P=0.012), major factors as pregnant women's IQ and gestational diabetes mellitus, premature delivery and education levels of fosterers on these pregnant women were under control. Our results from the stratified analysis showed: when in the subgroup that mother was the main fosterer of the child, there was an significant increase of risk in children whose mothers with pregnancy-related anxiety during both trimesters (RR=4.22, 95%CI: 1.73-10.32, P=0.002). Conclusion: The association between pregnancy-related anxiety and autism-like behavior was not strong but influenced by the fosterer of the child.

Memantine rescues prenatal citalopram exposure-induced striatal and social abnormalities in mice.

Prenatal exposure to citalopram (CTM), an antidepressant drug, has been associated with altered behavior, including autism-like symptoms in both human and rodent offspring. However, the neurological basis underlying these abnormal behaviors is not well understood. Here, we examined behavioral, morphological, and biochemical alterations in the male and female offspring of C57BL/6 mouse mothers that had been exposed to CTM during the last trimester of gestation. We observed abnormal behavior such as anxiety, altered locomotion and disordered social interactions in 2-5 months old offspring with prenatal CTM exposure. Using Golgi-Cox staining, we found that CTM caused significantly reduced dendritic length and number of dendritic branches in striatal neurons, as well as altered subunit levels of N-methyl-d-aspartate receptors (NMDARs) and calcium/calmodulin-dependent protein kinase II (CaMKII). Memantine, a selective NMDAR antagonist, improved prenatal CTM-induced abnormal protein levels and social interaction deficits. These results highlight potential mechanisms underlying the abnormal behavior observed in children who are prenatally exposed to CTM.

Combined fetal inflammation and postnatal hypoxia causes myelin deficits and autism-like behavior in a rat model of diffuse white matter injury.

Diffuse white matter injury (WMI) is a serious problem in extremely preterm infants, and is associated with adverse neurodevelopmental outcome, including cognitive impairments and an increased risk of autism-spectrum disorders. Important risk factors include fetal or perinatal inflammatory insults and fluctuating cerebral oxygenation. However, the exact mechanisms underlying diffuse WMI are not fully understood and no treatment options are currently available. The use of clinically relevant animal models is crucial to advance knowledge on the pathophysiology of diffuse WMI, allowing the definition of novel therapeutic targets. In the present study, we developed a multiple-hit animal model of diffuse WMI by combining fetal inflammation and postnatal hypoxia in rats. We characterized the effects on white matter development and functional outcome by immunohistochemistry, MRI and behavioral paradigms. Combined fetal inflammation and postnatal hypoxia resulted in delayed cortical myelination, microglia activation and astrogliosis at P18, together with long-term changes in oligodendrocyte maturation as observed in 10 week old animals. Furthermore, rats with WMI showed impaired motor performance, increased anxiety and signs of autism-like behavior, i.e. reduced social play behavior and increased repetitive grooming. In conclusion, the combination of fetal inflammation and postnatal hypoxia in rats induces a pattern of brain injury and functional impairments that closely resembles the clinical situation of diffuse WMI. This animal model provides the opportunity to elucidate pathophysiological mechanisms underlying WMI, and can be used to develop novel treatment options for diffuse WMI in preterm infants.

Association between pregnancy-related anxiety of pregnant women and autism-like behavior in their offspring at 18 months of age / 中华流行病学杂志

Objective: To investigate the relationship of pregnancy-related anxiety of pregnant women in second/third trimesters and autism-like behaviors in their offspring at 18 months of age. Methods: Based on a prospective cohort study design, we evaluated the situation of pregnancy-related anxiety of women during second and third trimesters through a Pregnancy-Related Anxiety Questionnaire. Subjects under study were classified into three groups, 1) those with pregnancy- related anxiety during both trimesters, 2) those with pregnancy-related anxiety at one trimester and 3) those without pregnancy-related anxiety in either trimester. When their children were 18 months, autism-like behaviors (ALB) were evaluated, using the part A of Checklist for Autism in Toddlers-23, and then classified into three groups as non-ALB group, minor ALB group and major ALB group. Multi-nominal logistic Regression was used to analyze the relationship of pregnancy-related anxiety with autism-like behaviors. Results: Compared with non-ALB group, children whose mother with pregnancy-related anxiety during both trimesters presented significant higher risk on ALB than children whose mother without pregnancy-related anxiety in these two periods (relative risk, RR=2.43, 95% CI: 1.21-4.86, P=0.012), major factors as pregnant women's IQ and gestational diabetes mellitus, premature delivery and education levels of fosterers on these pregnant women were under control. Our results from the stratified analysis showed: when in the subgroup that mother was the main fosterer of the child, there was an significant increase of risk in children whose mothers with pregnancy-related anxiety during both trimesters (RR=4.22, 95%CI: 1.73-10.32, P=0.002). Conclusion: The association between pregnancy-related anxiety and autism-like behavior was not strong but influenced by the fosterer of the child.

Association between pregnancy-related anxiety of pregnant women and autism-like behavior in their offspring at 18 months of age / 中华流行病学杂志

Objective To investigate the relationship of pregnancy-related anxiety of pregnant women in second/third trimesters and autism-like behaviors in their offspring at 18 months of age.Methods Based on a prospective cohort study design,we evaluated the situation of pregnancy-related anxiety of women during second and third trimesters through a Pregnancy-Related Anxiety Questionnaire.Subjects under study were classified into three groups,1) those with pregnancy-related anxiety during both trimesters,2) those with pregnancy-related anxiety at one trimester and 3) those without pregnancy-related anxiety in either trimester.When their children were 18 months,autism-like behaviors (ALB) were evaluated,using the part A of Checklist for Autism in Toddlers-23,and then classified into three groups as non-ALB group,minor ALB group and major ALB group.Multi-nominal logistic Regression was used to analyze the relationship of pregnancy-related anxiety with autism-like behaviors.Results Compared with non-ALB group,children whose mother with pregnancy-related anxiety during both trimesters presented significant higher risk on ALB than children whose mother without pregnancy-related anxiety in these two periods (relative risk,RR=2.43,95％ CI:1.21-4.86,P=0.012),major factors as pregnant women's IQ and gestational diabetes mellitus,premature delivery and education levels of fosterers on these pregnant women were under control.Our results from the stratified analysis showed:when in the subgroup that mother was the main fosterer of the child,there was an significant increase of risk in children whose mothers with pregnancy-related anxiety during both trimesters (RR=4.22,95％ CI:1.73-10.32,P=0.002).Conclusion The association between pregnancy-related anxiety and autism-like behavior was not strong but influenced by the fosterer of the child.

Prenatal levonorgestrel exposure induces autism-like behavior in offspring through ERß suppression in the amygdala.

BACKGROUND: Autism spectrum disorder (ASD) is characterized by impairments in social communication and restricted or repetitive behaviors or interests. ASD is now diagnosed in more than one out of 100 children and is biased towards males by a ratio of at least 4:1. Many possible explanations and potential causative factors have been reported, such as genetics, sex, and environmental factors, although the detailed mechanisms of ASD remain unclear. METHODS: The dams were exposed through oral contraceptives to either vehicle control (VEH) alone, levonorgestrel (LNG) alone, ethinyl estradiol (EE) alone, or a combination of LNG/EE for 21 days during their pregnancy. The subsequent 10-week-old offspring were used for autism-like behavior testing, and the limbic tissues were isolated for analysis. In another experimental group, 8-week-old male offspring were treated by infusion of ERß overexpression/knockdown lentivirus in the amygdala, and the offspring were analyzed after 2 weeks. RESULTS: We show that prenatal exposure of either LNG alone or a LNG/EE combination, but not EE alone, results in suppression of ERß (estrogen receptor ß) and its target genes in the amygdala with autism-like behavior in male offspring, while there is a much smaller effect on female offspring. However, we find that there is no effect on the hippocampus and hypothalamus. Further investigation shows that ERß suppression is due to LNG-mediated altered methylation on the ERß promoter and results in tissue damage with oxidative stress and the dysfunction of mitochondria and fatty acid metabolism, which subsequently triggers autism-like behavior. Overexpression of ERß in the amygdala completely restores LNG-induced ERß suppression and autism-like behaviors in offspring, while ERß knockdown mimics this effect, indicating that ERß expression in the amygdala plays an important role in autism-like behavior development. CONCLUSIONS: We conclude that prenatal levonorgestrel exposure induces autism-like behavior in offspring through ERß suppression in the amygdala. To our knowledge, this is the first time the potential effect of oral contraceptives on the contribution of autism-like behavior in offspring has been discovered.